Bio

Clinical Focus


  • Plastic and Reconstructive Surgery

Academic Appointments


Professional Education


  • Medical Education:Columbia University (2001) NY
  • Internship:New York University Med Ctr (2002) NY
  • Residency:UCSF - General Surgery (2007) CA
  • Residency:UCLA (2009) CA
  • Fellowship:UCLA (2010) CA
  • Fellowship:Chang Gung Memorial Hospital (2011) Taiwan

Teaching

2013-14 Courses


Publications

Journal Articles


  • Isolation of human adipose-derived stromal cells using laser-assisted liposuction and their therapeutic potential in regenerative medicine. Stem cells translational medicine Chung, M. T., Zimmermann, A. S., Paik, K. J., Morrison, S. D., Hyun, J. S., Lo, D. D., McArdle, A., Montoro, D. T., Walmsley, G. G., Senarath-Yapa, K., Sorkin, M., Rennert, R., Chen, H., Chung, A. S., Vistnes, D., Gurtner, G. C., Longaker, M. T., Wan, D. C. 2013; 2 (10): 808-817

    Abstract

    Harvesting adipose-derived stromal cells (ASCs) for tissue engineering is frequently done through liposuction. However, several different techniques exist. Although third-generation ultrasound-assisted liposuction has been shown to not have a negative effect on ASCs, the impact of laser-assisted liposuction on the quality and differentiation potential of ASCs has not been studied. Therefore, ASCs were harvested from laser-assisted lipoaspirate and suction-assisted lipoaspirate. Next, in vitro parameters of cell yield, cell viability and proliferation, surface marker phenotype, osteogenic differentiation, and adipogenic differentiation were performed. Finally, in vivo bone formation was assessed using a critical-sized cranial defect in athymic nude mice. Although ASCs isolated from suction-assisted lipoaspirate and laser-assisted lipoaspirate both successfully underwent osteogenic and adipogenic differentiation, the cell yield, viability, proliferation, and frequency of ASCs (CD34(+)CD31(-)CD45(-)) in the stromal vascular fraction were all significantly less with laser-assisted liposuction in vitro (p < .05). In vivo, quantification of osseous healing by micro-computed tomography revealed significantly more healing with ASCs isolated from suction-assisted lipoaspirate relative to laser-assisted lipoaspirate at the 4-, 6-, and 8-week time points (p < .05). Therefore, as laser-assisted liposuction appears to negatively impact the biology of ASCs, cell harvest using suction-assisted liposuction is preferable for tissue-engineering purposes.

    View details for DOI 10.5966/sctm.2012-0183

    View details for PubMedID 24018794

  • Molecular analysis and differentiation capacity of adipose-derived stem cells from lymphedema tissue. Plastic and reconstructive surgery Levi, B., Glotzbach, J. P., Sorkin, M., Hyun, J., Januszyk, M., Wan, D. C., Li, S., Nelson, E. R., Longaker, M. T., Gurtner, G. C. 2013; 132 (3): 580-589

    Abstract

    Many breast cancer patients are plagued by the disabling complication of upper limb lymphedema after axillary surgery. Conservative treatments using massage and compression therapy do not offer a lasting relief, as they fail to address the chronic transformation of edema into excess adipose tissue. Liposuction to address the adipose nature of the lymphedema has provided an opportunity for a detailed analysis of the stromal fraction of lymphedema-associated fat to clarify the molecular mechanisms for this adipogenic transformation.Adipose-derived stem cells were harvested from human lipoaspirate of the upper extremity from age-matched patients with lymphedema (n = 3) or subcutaneous adipose tissue from control patients undergoing cosmetic procedures (n = 3). Immediately after harvest, adipose-derived stem cells were analyzed using single-cell transcriptional profiling techniques. Osteogenic, adipogenic, and vasculogenic gene expression and differentiation were assessed by quantitative real-time polymerase chain reaction and standard in vitro differentiation assays.Differential transcriptional clusters of adipose-derived stem cells were found between lymphedema and subcutaneous fat. Interestingly, lymphedema-associated stem cells had a much higher adipogenic gene expression and enhanced ability to undergo adipogenic differentiation. Conversely, they had lower vasculogenic gene expression and diminished capability to form tubules in vitro, whereas the osteogenic differentiation capacity was not significantly altered.Adipose-derived stem cells from extremities affected by lymphedema appear to exhibit transcriptional profiles similar to those of abdominal adipose-derived stem cells; however, their adipogenic differentiation potential is strongly increased and their vasculogenic capacity is compromised. These results suggest that the underlying pathophysiology of lymphedema drives adipose-derived stem cells toward adipogenic differentiation.

    View details for DOI 10.1097/PRS.0b013e31829ace13

    View details for PubMedID 23985633

  • Enhancing stem cell survival in vivo for tissue repair BIOTECHNOLOGY ADVANCES Hyun, J. S., Tran, M. C., Wong, V. W., Chung, M. T., Lo, D. D., Montoro, D. T., Wan, D. C., Longaker, M. T. 2013; 31 (5): 736-743

    Abstract

    The ability to use progenitor cells for regenerative medicine remains an evolving but elusive clinical goal. A serious obstacle towards widespread use of stem cells for tissue regeneration is the challenges that face these cells when they are placed in vivo into a wound for therapy. These environments are hypoxic, acidic, and have an upregulation of inflammatory mediators creating a region that is hostile towards cellular survival. Within this environment, the majority of progenitor cells undergo apoptosis prior to participating in lineage differentiation and cellular integration. In order to maximize the clinical utility of stem cells, strategies must be employed to increase the cell's ability to survive in vivo through manipulation of both the stem cell and the surrounding environment. This review focuses on current advances and techniques being used to increase in vivo stem cell survival for the purpose of tissue regeneration.

    View details for DOI 10.1016/j.biotechadv.2012.11.003

    View details for Web of Science ID 000322058900019

    View details for PubMedID 23153460

  • Enhancing in vivo survival of adipose-derived stromal cells through bcl-2 overexpression using a minicircle vector. Stem cells translational medicine Hyun, J., Grova, M., Nejadnik, H., Lo, D., Morrison, S., Montoro, D., Chung, M., Zimmermann, A., Walmsley, G. G., Lee, M., Daldrup-Link, H., Wan, D. C., Longaker, M. T. 2013; 2 (9): 690-702

    Abstract

    Tissue regeneration using progenitor cell-based therapy has the potential to aid in the healing of a diverse range of pathologies, ranging from short-gut syndrome to spinal cord lesions. However, there are numerous hurdles to be overcome prior to the widespread application of these cells in the clinical setting. One of the primary barriers to effective stem cell therapy is the hostile environment that progenitor cells encounter in the clinical injury wound setting. In order to promote cellular survival, stem cell differentiation, and participation in tissue regeneration, relevant cells and delivery scaffolds must be paired with strategies to prevent cell death to ensure that these cells can survive to form de novo tissue. The Bcl-2 protein is a prosurvival member of a family of proteins that regulate the mitochondrial pathway of apoptosis. Using several strategies to overexpress the Bcl-2 protein, we demonstrated a decrease in the mediators of apoptosis in vitro and in vivo. This was shown through the use of two different clinical tissue repair models. Cells overexpressing Bcl-2 not only survived within the wound environment at a statistically significantly higher rate than control cells, but also increased tissue regeneration. Finally, we used a nonintegrating minicircle technology to achieve this in a potentially clinically applicable strategy for stem cell therapy.

    View details for DOI 10.5966/sctm.2013-0035

    View details for PubMedID 23934910

  • Clonal precursor of bone, cartilage, and hematopoietic niche stromal cells PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Chan, C. K., Lindau, P., Jiang, W., Chen, J. Y., Zhang, L. F., Chen, C., Seita, J., Sahoo, D., Kim, J., Lee, A., Park, S., Nag, D., Gong, Y., Kulkarni, S., Luppen, C. A., Theologis, A. A., Wan, D. C., DeBoer, A., Seo, E. Y., Vincent-Tompkins, J. D., Loh, K., Walmsley, G. G., Kraft, D. L., Wu, J. C., Longaker, M. T., Weissman, I. L. 2013; 110 (31): 12643-12648

    Abstract

    Organs are composites of tissue types with diverse developmental origins, and they rely on distinct stem and progenitor cells to meet physiological demands for cellular production and homeostasis. How diverse stem cell activity is coordinated within organs is not well understood. Here we describe a lineage-restricted, self-renewing common skeletal progenitor (bone, cartilage, stromal progenitor; BCSP) isolated from limb bones and bone marrow tissue of fetal, neonatal, and adult mice. The BCSP clonally produces chondrocytes (cartilage-forming) and osteogenic (bone-forming) cells and at least three subsets of stromal cells that exhibit differential expression of cell surface markers, including CD105 (or endoglin), Thy1 [or CD90 (cluster of differentiation 90)], and 6C3 [ENPEP glutamyl aminopeptidase (aminopeptidase A)]. These three stromal subsets exhibit differential capacities to support hematopoietic (blood-forming) stem and progenitor cells. Although the 6C3-expressing subset demonstrates functional stem cell niche activity by maintaining primitive hematopoietic stem cell (HSC) renewal in vitro, the other stromal populations promote HSC differentiation to more committed lines of hematopoiesis, such as the B-cell lineage. Gene expression analysis and microscopic studies further reveal a microenvironment in which CD105-, Thy1-, and 6C3-expressing marrow stroma collaborate to provide cytokine signaling to HSCs and more committed hematopoietic progenitors. As a result, within the context of bone as a blood-forming organ, the BCSP plays a critical role in supporting hematopoiesis through its generation of diverse osteogenic and hematopoietic-promoting stroma, including HSC supportive 6C3(+) niche cells.

    View details for DOI 10.1073/pnas.1310212110

    View details for Web of Science ID 000322441500042

    View details for PubMedID 23858471

  • CD90 (Thy-1)-Positive Selection Enhances Osteogenic Capacity of Human Adipose-Derived Stromal Cells TISSUE ENGINEERING PART A Chung, M. T., Liu, C., Hyun, J. S., Lo, D. D., Montoro, D. T., Hasegawa, M., Li, S., Sorkin, M., Rennert, R., Keeney, M., Yang, F., Quarto, N., Longaker, M. T., Wan, D. C. 2013; 19 (7-8): 989-997

    Abstract

    Stem cell-based bone tissue engineering with adipose-derived stromal cells (ASCs) has shown great promise for revolutionizing treatment of large bone deficits. However, there is still a lack of consensus on cell surface markers identifying osteoprogenitors. Fluorescence-activated cell sorting has identified a subpopulation of CD105(low) cells with enhanced osteogenic differentiation. The purpose of the present study was to compare the ability of CD90 (Thy-1) to identify osteoprogenitors relative to CD(105).Unsorted cells, CD90(+), CD90(-), CD105(high), and CD105(low) cells were treated with an osteogenic differentiation medium. For evaluation of in vitro osteogenesis, alkaline phosphatase (ALP) staining and alizarin red staining were performed at 7 days and 14 days, respectively. RNA was harvested after 7 and 14 days of differentiation, and osteogenic gene expression was examined by quantitative real-time polymerase chain reaction. For evaluation of in vivo osteogenesis, critical-sized (4-mm) calvarial defects in nude mice were treated with the hydroxyapatite-poly(lactic-co-glycolic acid) scaffold seeded with the above-mentioned subpopulations. Healing was followed using micro-CT scans for 8 weeks. Calvaria were harvested at 8 weeks postoperatively, and sections were stained with Movat's Pentachrome.Transcriptional analysis revealed that the CD90(+) subpopulation was enriched for a more osteogenic subtype relative to the CD105(low) subpopulation. Staining at day 7 for ALP was greatest in the CD90(+) cells, followed by the CD105(low) cells. Staining at day 14 for alizarin red demonstrated the greatest amount of mineralized extracellular matrix in the CD90(+) cells, again followed by the CD105(low) cells. Quantification of in vivo healing at 2, 4, 6, and 8weeks postoperatively demonstrated increased bone formation in defects treated with CD90(+) ASCs relative to all other groups. On Movat's Pentachrome-stained sections, defects treated with CD90(+) cells showed the most robust bony regeneration. Defects treated with CD90(-) cells, CD105(high) cells, and CD105(low) cells demonstrated some bone formation, but to a lesser degree when compared with the CD90(+) group.While CD105(low) cells have previously been shown to possess an enhanced osteogenic potential, we found that CD90(+) cells are more capable of forming bone both in vitro and in vivo. These data therefore suggest that CD90 may be a more effective marker than CD105 to isolate a highly osteogenic subpopulation for bone tissue engineering.

    View details for DOI 10.1089/ten.tea.2012.0370

    View details for Web of Science ID 000315951500016

    View details for PubMedID 23216074

  • Simultaneous reconstruction of extensor mechanism in the free transfer of vascularized proximal interphalangeal joint. Techniques in hand & upper extremity surgery Lin, Y., Kao, D. S., Wan, D. C., Lien, S., Lin, C., Wei, F. 2013; 17 (1): 20-24

    Abstract

    From a recent systemic review, vascularized toe proximal interphalangeal joint (PIPJ) transfer achieved an average arc of motion (AOM) of merely 37 degrees for finger PIPJ reconstruction. Despite the technical refinement over the past 3 decades, the resulting active motion of the reconstructed joint remains unpredictable and often fraught with extension lag. The technique for vascularized toe PIPJ transfer at our institute has evolved over the years to its current state, with simultaneous extensor mechanism reconstruction being a major component. During the transfer, the quality of extensor tendons on the recipient finger and donor toe are carefully evaluated. If the central slip of finger extensor is destroyed but the quality of lateral bands is adequate, centralization of lateral bands overlying the transferred PIPJ is performed. If there is acceptable central slip remnant at the proximal phalanx level, modified Stack procedure is performed for central slip reconstruction while leaving the lateral bands in continuity. If both lateral bands are poor, modified Stack procedure is performed unless the central tendon of the toe is strong enough to extend the PIPJ. From November 2008 to October 2010, 7 joints were transferred with this modified technique. The average follow-up was 18.2 months. The average active AOM of the transferred PIPJ was 56.4 degrees. The average extension lag of the toe PIPJ was 10.7 and 16.4 degrees before and after the transfer, respectively. Simultaneous reconstruction of extensor mechanism decreases the extension lag without sacrificing AOM of the transferred PIPJ.

    View details for DOI 10.1097/BTH.0b013e318272f918

    View details for PubMedID 23423230

  • Micro-Computed Tomography Evaluation of Human Fat Grafts in Nude Mice TISSUE ENGINEERING PART C-METHODS Chung, M. T., Hyun, J. S., Lo, D. D., Montoro, D. T., Hasegawa, M., Levi, B., Januszyk, M., Longaker, M. T., Wan, D. C. 2013; 19 (3): 227-232

    Abstract

    Although autologous fat grafting has revolutionized the field of soft tissue reconstruction and augmentation, long-term maintenance of fat grafts is unpredictable. Recent studies have reported survival rates of fat grafts to vary anywhere between 10% and 80% over time. The present study evaluated the long-term viability of human fat grafts in a murine model using a novel imaging technique allowing for in vivo volumetric analysis.Human fat grafts were prepared from lipoaspirate samples using the Coleman technique. Fat was injected subcutaneously into the scalp of 10 adult Crl:NU-Foxn1(nu) CD-1 male mice. Micro-computed tomography (CT) was performed immediately following injection and then weekly thereafter. Fat volume was rendered by reconstructing a three-dimensional (3D) surface through cubic-spline interpolation. Specimens were also harvested at various time points and sections were prepared and stained with hematoxylin and eosin (H&E), for macrophages using CD68 and for the cannabinoid receptor 1 (CB1). Finally, samples were explanted at 8- and 12-week time points to validate calculated micro-CT volumes.Weekly CT scanning demonstrated progressive volume loss over the time course. However, volumetric analysis at the 8- and 12-week time points stabilized, showing an average of 62.2% and 60.9% survival, respectively. Gross analysis showed the fat graft to be healthy and vascularized. H&E analysis and staining for CD68 showed minimal inflammatory reaction with viable adipocytes. Immunohistochemical staining with anti-human CB1 antibodies confirmed human origin of the adipocytes.Studies assessing the fate of autologous fat grafts in animals have focused on nonimaging modalities, including histological and biochemical analyses, which require euthanasia of the animals. In this study, we have demonstrated the ability to employ micro-CT for 3D reconstruction and volumetric analysis of human fat grafts in a mouse model. Importantly, this model provides a platform for subsequent study of fat manipulation and soft tissue engineering.

    View details for DOI 10.1089/ten.tec.2012.0371

    View details for Web of Science ID 000314179900006

    View details for PubMedID 22916732

  • Discussion: A Report of the ASPS Task Force on Regenerative Medicine: Opportunities for Plastic Surgery PLASTIC AND RECONSTRUCTIVE SURGERY McArdle, A., Lo, D. D., Hyun, J. S., Senarath-Yapa, K., Chung, M. T., Wan, D. C., Longaker, M. T. 2013; 131 (2): 400-403

    View details for DOI 10.1097/PRS.0b013e318278d88c

    View details for Web of Science ID 000314355700076

    View details for PubMedID 23358002

  • The Seed and the Soil Optimizing Stem Cells and Their Environment for Tissue Regeneration ANNALS OF PLASTIC SURGERY Hyun, J. S., Montoro, D. T., Lo, D. D., Flynn, R. A., Wong, V., Chung, M. T., Longaker, M. T., Wan, D. C. 2013; 70 (2): 235-239

    Abstract

    The potential for stem cells to serve as cellular building blocks for reconstruction of complex defects has prompted significant enthusiasm in the field of regenerative medicine. Clinical application, however, is still limited, as implantation of cells into hostile wound environments may greatly hinder their tissue forming capacity. To circumvent this obstacle, novel approaches have been developed to manipulate both the stem cell itself and its surrounding environmental niche. By understanding this paradigm of seed and soil optimization, innovative strategies may thus be developed to harness the true promise of stem cells for tissue regeneration.

    View details for DOI 10.1097/SAP.0b013e31826a18fb

    View details for Web of Science ID 000313964300024

    View details for PubMedID 23295233

  • Novel Application of Human Morphomics to Quantify Temporal Soft Tissues in Pierre Robin and Treacher Collins JOURNAL OF CRANIOFACIAL SURGERY Lisiecki, J., Wan, D. C., Wang, L., Zhang, P., Enchakalody, B., Zhang, X., Kasten, S. J., Wang, S. C., Buchman, S. R., Levi, B. 2013; 24 (1): 158-162

    Abstract

    Pierre Robin sequence (PR) and Treacher Collins syndrome (TC) are congenital disorders associated with multiple craniofacial abnormalities. The mandibular malformations linked with these maladies are closely associated with the form and function of the temporalis muscle. Despite these associations, a paucity of research has been directed at quantifying how these malformations affect the tissues of the temporal region. In this paper, we seek to quantify differences in the temporalis muscle and the temporal fat pad using a novel CT-derived analytic program to examine craniofacial morphomic indices within these patient groups in comparison to normal age-matched controls. We posit that the temporalis muscle and temporal fat pad, like other derivatives of the first branchial arch, are hypoplastic in patients with TC and PR compared to age-matched controls.High-throughput image analysis was used to reconstruct the 3-dimensional (3D) anatomy and quantify morphomic measures of the temporalis muscle and temporal fat pad in children with PR, TC, and age-matched controls. These steps were completed in a semi-automated method using algorithms programmed in MATLAB v13.0. The 3D reconstructions were analyzed in 3 children with PR (6 temporal regions), 3 children with TC (6 temporal regions), and a control group of 19 children (38 temporal regions). We also quantified the same measurements in a localized "core" sample in the area of greatest thickness, providing a more consistent sample of the tissue position. Relationships between the temporal muscle and fat pad values and craniofacial abnormality type were assessed using Wilcoxon nonparametric test using exact distribution, with a P value of less than 0.05 being deemed significant.The mean age of our patients was 6.0 years in PR and 4.5 years in TC cohorts. We were able to establish an automated methodology to quantify the temporalis muscle and temporal fat pad based on CT characteristics. Localized temporalis volume and localized temporalis area were significantly smaller in children with PR than in the control group. Total temporalis fat volume and localized temporalis area were significantly less in children with TC than in the control group. When compared to each other, the PR group had small morphomic values compared to TC group.There are significant morphomic differences in the temporalis muscle and the temporal fat pad in children with either PR or TC when compared to age-matched control group which can be measured from pre-existing CT scans. Specifically, both of these test groups show decreases in the morphomic measures of the temporalis region. The quantification of these changes corroborates and objectifies the clinical findings associated with these congenital deformities while simultaneously allowing for preoperative planning. Furthermore, this finding confirms that the hypoplasia seen in these patient populations is not only hypoplasia of the mandible but also of the surrounding functional matrix, which includes the temporalis muscle and temporal fat pad.

    View details for DOI 10.1097/SCS.0b013e3182646411

    View details for Web of Science ID 000314853300079

    View details for PubMedID 23348276

  • In vivo directed differentiation of pluripotent stem cells for skeletal regeneration PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Levi, B., Hyun, J. S., Montoro, D. T., Lo, D. D., Chan, C. K., Hu, S., Sun, N., Lee, M., Grova, M., Connolly, A. J., Wu, J. C., Gurtner, G. C., Weissman, I. L., Wan, D. C., Longaker, M. T. 2012; 109 (50): 20379-20384

    Abstract

    Pluripotent cells represent a powerful tool for tissue regeneration, but their clinical utility is limited by their propensity to form teratomas. Little is known about their interaction with the surrounding niche following implantation and how this may be applied to promote survival and functional engraftment. In this study, we evaluated the ability of an osteogenic microniche consisting of a hydroxyapatite-coated, bone morphogenetic protein-2-releasing poly-L-lactic acid scaffold placed within the context of a macroenvironmental skeletal defect to guide in vivo differentiation of both embryonic and induced pluripotent stem cells. In this setting, we found de novo bone formation and participation by implanted cells in skeletal regeneration without the formation of a teratoma. This finding suggests that local cues from both the implanted scaffold/cell micro- and surrounding macroniche may act in concert to promote cellular survival and the in vivo acquisition of a terminal cell fate, thereby allowing for functional engraftment of pluripotent cells into regenerating tissue.

    View details for DOI 10.1073/pnas.1218052109

    View details for Web of Science ID 000312605600055

    View details for PubMedID 23169671

  • Femtosecond plasma mediated laser ablation has advantages over mechanical osteotomy of cranial bone LASERS IN SURGERY AND MEDICINE Lo, D. D., Mackanos, M. A., Chung, M. T., Hyun, J. S., Montoro, D. T., Grova, M., Liu, C., Wang, J., Palanker, D., Connolly, A. J., Longaker, M. T., Contag, C. H., Wan, D. C. 2012; 44 (10): 805-814

    Abstract

    Although mechanical osteotomies are frequently made on the craniofacial skeleton, collateral thermal, and mechanical trauma to adjacent bone tissue causes cell death and may delay healing. The present study evaluated the use of plasma-mediated laser ablation using a femtosecond laser to circumvent thermal damage and improve bone regeneration.Critical-size circular calvarial defects were created with a trephine drill bit or with a Ti:Sapphire femtosecond pulsed laser. Healing was followed using micro-CT scans for 8 weeks. Calvaria were also harvested at various time points for histological analysis. Finally, scanning electron microscopy was used to analyze the microstructure of bone tissue treated with the Ti:Sapphire laser, and compared to that treated with the trephine bur.Laser-created defects healed significantly faster than those created mechanically at 2, 4, and 6 weeks post-surgery. However, at 8 weeks post-surgery, there was no significant difference. In the drill osteotomy treatment group, empty osteocyte lacunae were seen to extend 699?±?27?µm away from the edge of the defect. In marked contrast, empty osteocyte lacunae were seen to extend only 182?±?22?µm away from the edge of the laser-created craters. Significantly less ossification and formation of irregular woven bone was noted on histological analysis for drill defects.We demonstrate accelerated bone healing after femtosecond laser ablation in a calvarial defect model compared to traditional mechanical drilling techniques. Improved rates of early regeneration make plasma-mediated ablation of the craniofacial skeleton advantageous for applications to osteotomy.

    View details for DOI 10.1002/lsm.22098

    View details for Web of Science ID 000312941600004

    View details for PubMedID 23184427

  • Pierre Robin sequence and Treacher Collins hypoplastic mandible comparison using three-dimensional morphometric analysis. journal of craniofacial surgery Chung, M. T., Levi, B., Hyun, J. S., Lo, D. D., Montoro, D. T., Lisiecki, J., Bradley, J. P., Buchman, S. R., Longaker, M. T., Wan, D. C. 2012; 23 (7): 1959-1963

    Abstract

    Pierre Robin sequence and Treacher Collins syndrome are both associated with mandibular hypoplasia. It has been hypothesized, however, that the mandible may be differentially affected. The purpose of this study was to therefore compare mandibular morphology in children with Pierre Robin sequence with children with Treacher Collins syndrome using three-dimensional analysis of computed tomographic scans. A retrospective analysis was performed identifying children with Pierre Robin sequence and Treacher Collins syndrome undergoing computed tomography. Three-dimensional reconstruction was performed, and ramus height, mandibular body length, and gonial angle were measured. These were then compared with those in control children with normal mandibles and with the clinical norms corrected for age and sex based on previously published measurements. Mandibular body length was found to be significantly shorter for children with Pierre Robin sequence, whereas ramus height was significantly shorter for children with Treacher Collins syndrome. This resulted in distinctly different ramus height-mandibular body length ratios. In addition, the gonial angle was more obtuse in both the Pierre Robin sequence and Treacher Collins syndrome groups compared with the controls. Three-dimensional mandibular morphometric analysis in patients with Pierre Robin sequence and Treacher Collins syndrome thus revealed distinctly different patterns of mandibular hypoplasia relative to normal controls. These findings underscore distinct considerations that must be made in surgical planning for reconstruction.

    View details for DOI 10.1097/SCS.0b013e318258bcf1

    View details for PubMedID 23154353

  • Models of cranial suture biology. journal of craniofacial surgery Grova, M., Lo, D. D., Montoro, D., Hyun, J. S., Chung, M. T., Wan, D. C., Longaker, M. T. 2012; 23 (7): 1954-1958

    Abstract

    Craniosynostosis is a common congenital defect caused by premature fusion of cranial sutures. The severe morphologic abnormalities and cognitive deficits resulting from craniosynostosis and the potential morbidity of surgical correction espouse the need for a deeper understanding of the complex etiology for this condition. Work in animal models for the past 20 years has been pivotal in advancing our understanding of normal suture biology and elucidating pathologic disease mechanisms. This article provides an overview of milestone studies in suture development, embryonic origins, and signaling mechanisms from an array of animal models including transgenic mice, rats, rabbits, fetal sheep, zebrafish, and frogs. This work contributes to an ongoing effort toward continued development of novel treatment strategies.

    View details for DOI 10.1097/SCS.0b013e318258ba53

    View details for PubMedID 23154351

  • Craniosynostosis Molecular pathways and future pharmacologic therapy ORGANOGENESIS Senarath-Yapa, K., Chung, M. T., McArdle, A., Wong, V. W., Quarto, N., Longaker, M. T., Wan, D. C. 2012; 8 (4): 103-113

    View details for DOI 10.4161/org.23307

    View details for Web of Science ID 000314500600002

  • Regenerative Surgery: Tissue Engineering in General Surgical Practice WORLD JOURNAL OF SURGERY Wong, V. W., Wan, D. C., Gurtner, G. C., Longaker, M. T. 2012; 36 (10): 2288-2299

    Abstract

    Tissue engineering is a broad interdisciplinary field that aims to develop complex tissue and organ constructs through a combination of cell-, biomaterial-, and molecular-based approaches. This approach has the potential to transform the surgical treatment for diseases including trauma, cancer, and congenital malformations. A fundamental knowledge of key concepts in regenerative medicine is imperative for surgeons to maintain a leading role in developing and implementing these technologies. Researchers have started to elucidate the biologic mechanisms that maintain organ homeostasis throughout life, indicating that humans may have the latent capacity to regenerate complex tissues. By exploiting this intrinsic potential of the body, we can move even closer to developing functional, autologous replacement parts for a wide range of surgical diseases.

    View details for DOI 10.1007/s00268-012-1710-1

    View details for Web of Science ID 000309559800003

    View details for PubMedID 22777416

  • Autologous Fat Transplantation in the Craniofacial Patient: The UCLA Experience JOURNAL OF CRANIOFACIAL SURGERY Lim, A. A., Fan, K., Allam, K. A., Wan, D., Tabit, C., Liao, E., Kawamoto, H. K., Bradley, J. P. 2012; 23 (4): 1061-1066

    Abstract

    Patients with congenital craniofacial malformations present with complex challenges for reconstruction. Successful management requires individualized treatment often involving rebuilding the facial skeleton de novo, as well as correcting the overlying soft-tissue deficiencies in the final stages. At the University of California, Los Angeles (UCLA) Craniofacial Clinic, serial autologous fat transplantation performed during staged reconstruction is the preferred method.A total of 27 patients with a diagnosis of either craniofacial microsomia/Goldenhar (CM) (n = 19) or Treacher Collins syndrome (TC) (n = 8) were treated at the UCLA Craniofacial Clinic by autologous fat transfer between July 1999 and February 2009. Two-dimensional analysis was conducted on standardized preoperative and postoperative photographs to determine facial symmetry for every patient. Results was grouped based on pathology and analyzed by comparing adipocyte donor site (abdomen vs other).The mean ages at the time of first fat transfer were 17 years for the CM group and 15 years for the TC group. The average numbers of fat transfers per patient were 2.05 (CM) and 2.12 (TC). A mean of 3.74 procedures other than fat grafting was performed in each CM patient, whereas 4.38 other procedures were performed in each TC patient. In CM patients, less than 10.5 months between procedures resulted in improved symmetry. There was an average 6.63% improvement in facial symmetry in the CM group, and a 7.67% improvement in the TC group.Based on the UCLA experience, the durability of facial asymmetry and contour correction with fat transplantation is attainable in the craniofacial patient but may also require concomitant skeletal correction in the most severe cases.

    View details for DOI 10.1097/SCS.0b013e31824e695b

    View details for Web of Science ID 000306710200069

    View details for PubMedID 22777454

  • Fat Grafting Versus Adipose-Derived Stem Cell Therapy: Distinguishing Indications, Techniques, and Outcomes AESTHETIC PLASTIC SURGERY Tabit, C. J., Slack, G. C., Fan, K., Wan, D. C., Bradley, J. P. 2012; 36 (3): 704-713

    Abstract

    With adipose-derived stem cells (ASCs) at the forefront of research and potential clinical applications, it is important that clinicians be able to distinguish them from the fat grafting currently used clinically and to understand how the two approaches relate to one another. At times, there has been confusion in clinically considering the two therapies to be the same. This report is aimed at distinguishing clearly between fat grafting and ASC therapy with regard to the indications, harvesting, processing, application techniques, outcomes, and complications. Findings have shown that autologous fat transfer, a widely used procedure for soft tissue augmentation, is beneficial for reconstructive and cosmetic procedures used to treat patients with volume loss due to disease, trauma, congenital defects, or the natural process of aging. On the other hand, ASCs have been identified as an ideal source of cells for regenerative medicine, with the potential to serve as soft tissue therapy for irradiated, scarred, or chronic wounds. Recent advances in tissue engineering suggest that the supplementation of fat grafts with ASCs isolated in the stromal vascular fraction may increase the longevity and quality of the fat graft. Research suggests that ASC supplementation may be a great clinical tool in the future, but more data should be acquired before clinical applications.

    View details for DOI 10.1007/s00266-011-9835-4

    View details for Web of Science ID 000304203800034

    View details for PubMedID 22069062

  • Craniofacial Reconstruction With Induced Pluripotent Stem Cells JOURNAL OF CRANIOFACIAL SURGERY Wan, D. C., Wong, V. W., Longaker, M. T. 2012; 23 (3): 623-626

    View details for DOI 10.1097/SCS.0b013e318252f41b

    View details for Web of Science ID 000304479600041

    View details for PubMedID 22627398

  • Rethinking the Blastema PLASTIC AND RECONSTRUCTIVE SURGERY Hyun, J. S., Chung, M. T., Wong, V. W., Montoro, D., Longaker, M. T., Wan, D. C. 2012; 129 (5): 1097-1103

    Abstract

    The phenomenon of tissue regeneration has been well documented across many species. Although some possess the capacity to completely restore an entire amputated limb, others are limited to just the distal digit tip. Initiation of limb regeneration has been described to start with the formation of a blastema, the composition of which has long been thought to consist of undifferentiated pluripotent cells derived through the process of dedifferentiation. Competing theories have been proposed, however, including cellular contributions through transdifferentiation and tissue-specific stem cells. Recent studies have now begun to shed light on this controversy, demonstrating tissue resident stem cells to be an evolutionarily conserved measure for limb regeneration.

    View details for DOI 10.1097/PRS.0b013e31824a2c49

    View details for Web of Science ID 000303497300059

    View details for PubMedID 22544093

  • Training the Contemporary Surgeon-Scientist PLASTIC AND RECONSTRUCTIVE SURGERY Wan, D. C., Wang, K. C., Longaker, M. T. 2012; 129 (4): 1023-1025

    View details for DOI 10.1097/PRS.0b013e31824421e8

    View details for Web of Science ID 000302227100076

    View details for PubMedID 22456371

  • The commissure-based triangular flap for lip revision following reconstruction of a through-and-through defect JOURNAL OF PLASTIC RECONSTRUCTIVE AND AESTHETIC SURGERY Tsao, C., Wan, D. C., Chen, W., Kao, D. S., Levi, B. 2012; 65 (2): 271-273

    View details for DOI 10.1016/j.bjps.2011.08.007

    View details for Web of Science ID 000299111100028

    View details for PubMedID 21945062

  • Stem Cells: Update and Impact on Craniofacial Surgery JOURNAL OF CRANIOFACIAL SURGERY Levi, B., Glotzbach, J. P., Wong, V. W., Nelson, E. R., Hyun, J., Wan, D. C., Gurtner, G. C., Longaker, M. T. 2012; 23 (1): 319-322

    View details for DOI 10.1097/SCS.0b013e318241dbaf

    View details for Web of Science ID 000300234900099

    View details for PubMedID 22337434

  • Cranial Suture Biology: From Pathways to Patient Care JOURNAL OF CRANIOFACIAL SURGERY Levi, B., Wan, D. C., Wong, V. W., Nelson, E., Hyun, J., Longaker, M. T. 2012; 23 (1): 13-19

    Abstract

    Craniosynostosis describes the premature pathologic partial or complete fusion of 1 or more of the cranial sutures. Over the past few decades, research on craniosynostosis has progressed from gross description of deformities to an understanding of some of the molecular etiologies behind premature suture fusion. Studies on patients with syndromic craniosynostosis have resulted in the identification of several genes, molecular events, and deformational forces involved in abnormal growth and development of the cranial vault. Conservation of craniofacial development and sequence homology between humans and other species have also led to insightful discoveries in cranial suture development. In this review, we discuss the development of the cranial vault and explain the basic science behind craniosynostosis in humans as well as in animal models and how these studies may lead to future advances in craniosynostosis treatments.

    View details for DOI 10.1097/SCS.0b013e318240c6c0

    View details for Web of Science ID 000300234900033

    View details for PubMedID 22337368

  • Open Reduction and Internal Fixation of Mandibular Angle Fractures Using Temporary Kirschner Wire Fixation PLASTIC AND RECONSTRUCTIVE SURGERY Perry, A. D., Wan, D. C., Shih, H., Tanna, N., Bradley, J. P. 2012; 129 (1): 192E-194E

    View details for DOI 10.1097/PRS.0b013e3182365ceb

    View details for Web of Science ID 000298857100047

    View details for PubMedID 22186559

  • Repair of a critical-sized calvarial defect model using adipose-derived stromal cells harvested from lipoaspirate. Journal of visualized experiments : JoVE Lo, D. D., Hyun, J. S., Chung, M. T., Montoro, D. T., Zimmermann, A., Grova, M. M., Lee, M., Wan, D. C., Longaker, M. T. 2012

    Abstract

    Craniofacial skeletal repair and regeneration offers the promise of de novo tissue formation through a cell-based approach utilizing stem cells. Adipose-derived stromal cells (ASCs) have proven to be an abundant source of multipotent stem cells capable of undergoing osteogenic, chondrogenic, adipogenic, and myogenic differentiation. Many studies have explored the osteogenic potential of these cells in vivo with the use of various scaffolding biomaterials for cellular delivery. It has been demonstrated that by utilizing an osteoconductive, hydroxyapatite-coated poly(lactic-co-glycolic acid) (HA-PLGA) scaffold seeded with ASCs, a critical-sized calvarial defect, a defect that is defined by its inability to undergo spontaneous healing over the lifetime of the animal, can be effectively show robust osseous regeneration. This in vivo model demonstrates the basis of translational approaches aimed to regenerate the bone tissue - the cellular component and biological matrix. This method serves as a model for the ultimate clinical application of a progenitor cell towards the repair of a specific tissue defect.

    View details for DOI 10.3791/4221

    View details for PubMedID 23149856

  • Craniosynostosis: Molecular pathways and future pharmacologic therapy. Organogenesis Senarath-Yapa, K., Chung, M. T., McArdle, A., Wong, V. W., Quarto, N., Longaker, M. T., Wan, D. C. 2012; 8 (4)

    Abstract

    Craniosynostosis describes the premature fusion of one or more cranial sutures and can lead to dramatic manifestations in terms of appearance and functional impairment. Contemporary approaches for this condition are primarily surgical and are associated with considerable morbidity and mortality. The additional post-operative problems of suture refusion and bony relapse may also necessitate repeated surgeries with their own attendant risks. Therefore, a need exists to not only optimize current strategies but also to develop novel biological therapies which could obviate the need for surgery and potentially treat or even prevent premature suture fusion. Clinical studies of patients with syndromic craniosynostosis have provided some useful insights into the important signaling pathways and molecular events guiding suture fate. Furthermore, the highly conserved nature of craniofacial development between humans and other species have permitted more focused and step-wise elucidation of the molecular underpinnings of craniosynostosis. This review will describe the clinical manifestations of craniosynostosis, reflect on our understanding of syndromic and non-syndromic craniosynostoses and outline the different approaches that have been adopted in our laboratory and elsewhere to better understand the pathogenesis of premature suture fusion. Finally, we will assess to what extent our improved understanding of the pathogenesis of craniosynostosis, achieved through laboratory-based and clinical studies, have made the possibility of a non-surgical pharmacological approach both realistic and tangible.

    View details for PubMedID 23249483

  • Paramedian Mandibular Cleft: Revisiting the Tessier Classification JOURNAL OF CRANIOFACIAL SURGERY Tanna, N., Wan, D. C., Perry, A. D., Kawamoto, H. K., Bradley, J. P. 2012; 23 (1): E38-E40

    Abstract

    Mandibular clefts are extremely rare, with less than 100 cases reported in the literature. Almost universally, these isolated cases of lower facial clefting have been noted to occur through the midline of the lip and/or mandible. The defect can vary, ranging from mild notching of the lower lip or mandibular alveolus to complete mandibular cleavage. The authors present a rare case of a paramedian mandibular cleft in a patient who also had Goldenhar syndrome and Tessier number 2/12 cleft. With its presentation, the authors revisit the Tessier classification of craniofacial clefts and the embryogenesis of lower facial clefts.

    View details for DOI 10.1097/SCS.0b013e318241db58

    View details for Web of Science ID 000300234900017

    View details for PubMedID 22337459

  • Correction of Hypertelorbitism: Evaluation of Relapse on Long-Term Follow-Up JOURNAL OF CRANIOFACIAL SURGERY Wan, D. C., Levi, B., Kawamoto, H., Tanna, N., Tabit, C., do Amaral, C. R., Bradley, J. P. 2012; 23 (1): 113-117

    Abstract

    Hypertelorbitism has been associated with a variety of congenital deformities. Appropriate timing for surgical correction remains controversial. We present our long-term experience of 33 patients with hypertelorbitism undergoing facial bipartition or orbital box osteotomy.Patients with hypertelorbitism treated with either facial bipartition or orbital box osteotomy and repositioning who had long-term follow-up were studied (n=33). Age at the time of first surgery, preoperative interdacryon distance, and immediate postoperative interdacryon distance were recorded. Relapse was determined on postoperative follow-up, and the need for secondary correction was noted. Physician satisfaction score (range, 0-4) was also assessed.Patients had a mean total follow-up of 14.0 years. With regard to age at the time of initial procedure, patients younger than 6 years were all noted to have relapse, and 83% underwent revision surgery. In patients 6 years or older, only 11% had relapse and required a second operation. Yet, satisfaction scores were similar (3.2 versus 3.5). With regard to the severity of hypertelorbitism, there was no relapse noted among patients with mild hypertelorbitism (interorbital distance [IOD], 30-34 mm). Among those with moderate hypertelorbitism (IOD, 35-40 mm), 29.4% developed relapse. By contrast, all patients with severe hypertelorbitism (IOD, >40 mm) were noted to have relapse requiring repeat correction. Satisfaction scores were similar (3.4 versus 3.3 versus 3.1).Relapse after surgery for hypertelorbitism is related to the age of the patient at correction and the preoperative severity. When possible, surgical repositioning of the orbits should be delayed until later childhood.

    View details for DOI 10.1097/SCS.0b013e318240fa84

    View details for Web of Science ID 000300234900050

    View details for PubMedID 22337385

  • Nonintegrating Knockdown and Customized Scaffold Design Enhances Human Adipose-Derived Stem Cells in Skeletal Repair STEM CELLS Levi, B., Hyun, J. S., Nelson, E. R., Li, S., Montoro, D. T., Wan, D. C., Jia, F. J., Glotzbach, J. C., James, A. W., Lee, M., Huang, M., Quarto, N., Gurtner, G. C., Wu, J. C., Longaker, M. T. 2011; 29 (12): 2018-2029

    Abstract

    An urgent need exists in clinical medicine for suitable alternatives to available techniques for bone tissue repair. Human adipose-derived stem cells (hASCs) represent a readily available, autogenous cell source with well-documented in vivo osteogenic potential. In this article, we manipulated Noggin expression levels in hASCs using lentiviral and nonintegrating minicircle short hairpin ribonucleic acid (shRNA) methodologies in vitro and in vivo to enhance hASC osteogenesis. Human ASCs with Noggin knockdown showed significantly increased bone morphogenetic protein (BMP) signaling and osteogenic differentiation both in vitro and in vivo, and when placed onto a BMP-releasing scaffold embedded with lentiviral Noggin shRNA particles, hASCs more rapidly healed mouse calvarial defects. This study therefore suggests that genetic targeting of hASCs combined with custom scaffold design can optimize hASCs for skeletal regenerative medicine.

    View details for DOI 10.1002/stem.757

    View details for Web of Science ID 000297220000012

    View details for PubMedID 21997852

  • CD105 Protein Depletion Enhances Human Adipose-derived Stromal Cell Osteogenesis through Reduction of Transforming Growth Factor beta 1 (TGF-beta 1) Signaling JOURNAL OF BIOLOGICAL CHEMISTRY Levi, B., Wan, D. C., Glotzbach, J. P., Hyun, J., Januszyk, M., Montoro, D., Sorkin, M., James, A. W., Nelson, E. R., Li, S., Quarto, N., Lee, M., Gurtner, G. C., Longaker, M. T. 2011; 286 (45): 39497-39509

    Abstract

    Clinically available sources of bone for repair and reconstruction are limited by the accessibility of autologous grafts, infectious risks of cadaveric materials, and durability of synthetic substitutes. Cell-based approaches for skeletal regeneration can potentially fill this need, and adipose tissue represents a promising source for development of such therapies. Here, we enriched for an osteogenic subpopulation of cells derived from human subcutaneous adipose tissue utilizing microfluidic-based single cell transcriptional analysis and fluorescence-activated cell sorting (FACS). Statistical analysis of single cell transcriptional profiles demonstrated that low expression of endoglin (CD105) correlated with a subgroup of adipose-derived cells with increased osteogenic gene expression. FACS-sorted CD105(low) cells demonstrated significantly enhanced in vitro osteogenic differentiation and in vivo bone regeneration when compared with either CD105(high) or unsorted cells. Evaluation of the endoglin pathway suggested that enhanced osteogenesis among CD105(low) adipose-derived cells is likely due to identification of a subpopulation with lower TGF-?1/Smad2 signaling. These findings thus highlight a potential avenue to promote osteogenesis in adipose-derived mesenchymal cells for skeletal regeneration.

    View details for DOI 10.1074/jbc.M111.256529

    View details for Web of Science ID 000296759800067

    View details for PubMedID 21949130

  • Palatogenesis Engineering, pathways and pathologies ORGANOGENESIS Levi, B., Brugman, S., Wong, V. W., Grova, M., Longaker, M. T., Wan, D. C. 2011; 7 (4): 242-254

    Abstract

    Cleft palate represents the second most common birth defect and carries substantial physiologic and social challenges for affected patients, as they often require multiple surgical interventions during their lifetime. A number of genes have been identified to be associated with the cleft palate phenotype, but etiology in the majority of cases remains elusive. In order to better understand cleft palate and both surgical and potential tissue engineering approaches for repair, we have performed an in-depth literature review into cleft palate development in humans and mice, as well as into molecular pathways underlying these pathologic developments. We summarize the multitude of pathways underlying cleft palate development, with the transforming growth factor beta superfamily being the most commonly studied. Furthermore, while the majority of cleft palate studies are performed using a mouse model, studies focusing on tissue engineering have also focused heavily on mouse models. A paucity of human randomized controlled studies exists for cleft palate repair, and so far, tissue engineering approaches are limited. In this review, we discuss the development of the palate, explain the basic science behind normal and pathologic palate development in humans as well as mouse models and elaborate on how these studies may lead to future advances in palatal tissue engineering and cleft palate treatments.

    View details for DOI 10.4161/org.7.4.17926

    View details for Web of Science ID 000299593000002

    View details for PubMedID 21964245

  • Distraction Osteogenesis of Costocartilaginous Rib Grafts and Treatment Algorithm for Severely Hypoplastic Mandibles PLASTIC AND RECONSTRUCTIVE SURGERY Wan, D. C., Taub, P. J., Allam, K. A., Perry, A., Tabit, C. J., Kawamoto, H. K., Bradley, J. P. 2011; 127 (5): 2005-2013

    Abstract

    In craniofacial microsomia, patients with severely hypoplastic mandibles (Pruzansky type III) require replacement of the ramus and condyle unit. Autogenous costocartilaginous rib graft and distraction osteogenesis are the most important techniques used, but long-term results need to be looked at to determine optimal management.Of the 485 patients with craniofacial microsomia and mandibular abnormality identified by the authors' craniofacial multidisciplinary clinic, 31 patients were identified with Pruzansky type III mandibles who underwent treatment and were available for study. Patients primarily had either costocartilaginous grafts or mandibular distraction after molar extraction. Outcomes assessed rib failure, undergrowth, or overgrowth. Reoperation included regrafting for graft failure, rib distraction for undergrowth, and mandibular setback for overgrowth. Details surrounding complications for each modality including osteotomy site were recorded.For primary mandibular reconstruction, 27 patients underwent costocartilaginous rib graft surgery (30 grafts, three bilateral) at 9.9 ± 4.1 years; four patients underwent mandibular distraction at 7.4 ± 2.3 years. Rib graft failure in seven of 30 cases (23 percent) required regrafting. Undergrowth in 17 cases (57 percent) required rib distraction. Overgrowth in three cases (10 percent) required correction at the time of orthognathic correction. For rib graft distraction, osteotomy site locations included native mandible (25 percent), rib-mandible junction (19 percent), and rib graft (56 percent). The rib-mandible junction site had graft-related complications (100 percent) that the other sites did not.For the severely hypoplastic mandibles (Pruzansky type III), costocartilaginous grafts are an accepted modality. However, when rib graft growth is insufficient, secondary distraction should be performed within the native mandible or rib graft and not at the rib graft-mandible junction site.

    View details for DOI 10.1097/PRS.0b013e31820cf4d6

    View details for Web of Science ID 000290148100032

    View details for PubMedID 21532427

  • Treatment of Apert Syndrome: A Long-Term Follow-Up Study PLASTIC AND RECONSTRUCTIVE SURGERY Allam, K. A., Wan, D. C., Khwanngern, K., Kawamoto, H. K., Tanna, N., Perry, A., Bradley, J. P. 2011; 127 (4): 1601-1611

    Abstract

    Patients with Apert syndrome have severe malformations of the skull and face requiring multiple complex reconstructive procedures. The authors present a long-term follow-up study reporting both surgical results and psychosocial status of patients with Apert syndrome.A retrospective study was performed identifying patients with Apert syndrome treated between 1975 and 2009. All surgical procedures were recorded and a review of psychosocial and educational status was obtained when patients reached adulthood.A total of 31 patients with Apert syndrome were identified; nine with long-term follow-up had complete records for evaluation. The average patient age was 30.4 years. Primary procedures performed included strip craniectomy and fronto-orbital advancement. Monobloc osteotomy and facial bipartition were performed in eight patients, and all underwent surgical orthognathic correction. Multiple auxiliary procedures were also performed to achieve better facial symmetry. Mean follow-up after frontofacial advancement was 22.5 years. Psychosocial evaluation demonstrated good integration of patients into mainstream life.This report presents one of the longest available follow-up studies for surgical correction of patients with Apert syndrome. Although multiple reconstructive procedures were necessary, they play an important role in enhancing the psychosocial condition of the patients, helping them integrate into mainstream life.

    View details for DOI 10.1097/PRS.0b013e31820a64b6

    View details for Web of Science ID 000288840200025

    View details for PubMedID 21187805

  • Acute Skeletal Injury Is Necessary for Human Adipose-Derived Stromal Cell-Mediated Calvarial Regeneration PLASTIC AND RECONSTRUCTIVE SURGERY Levi, B., James, A. W., Nelson, E. R., Peng, M., Wan, D. C., Commons, G. W., Lee, M., Wu, B., Longaker, M. T. 2011; 127 (3): 1118-1129

    Abstract

    Studies have demonstrated that human adipose-derived stromal cells (ASCs) are able to repair acute calvarial injuries. The more clinically relevant repair of an established skeletal defect, however, has not been addressed. The authors sought to determine whether human ASCs could heal chronic (established) calvarial defects.Critical-sized (4 mm) mouse parietal defects were created. Human ASCs were engrafted either immediately postoperatively (acute defect) or 8 weeks following defect creation (established defect). Methods of analysis included microcomputer tomography scans, histology, and in situ hybridization. Finally, human ASCs were treated in vitro with platelet-rich plasma to simulate an acute wound environment; proliferation and osteogenic differentiation were assessed (alkaline phosphatase, alizarin red, and quantitative reverse transcriptase polymerase chain reaction).Nearly complete osseous healing was observed when calvarial defects were immediately engrafted with human ASCs. In contrast, when human ASCs were engrafted into established defects, little bone formation occurred. Histological analysis affirmed findings by microcomputer tomography, showing more robust staining for alkaline phosphatase and picrosirius red in an acute than in an established human ASC-engrafted defect. In situ hybridization and quantitative reverse transcriptase polymerase chain reaction showed an increase in bone morphogenetic protein (BMP) expression (BMP-2, BMP-4, and BMP-7) acutely following calvarial defect creation. Finally, in vitro treatment of human ASCs with platelet-rich plasma enhanced osteogenic differentiation and increased BMP-2 expression.Although human ASCs can be utilized to heal an acute mouse calvarial defect, they do not enhance healing of an established (or chronic) defect. Endogenous BMP signaling activated after injury may explain these differences in healing. Platelet-rich plasma enhances osteogenic differentiation of human ASCs in vitro and may prove a promising therapy for future skeletal tissue engineering efforts.

    View details for DOI 10.1097/PRS.0b013e318205f274

    View details for Web of Science ID 000287680200012

    View details for PubMedID 21364415

  • The Spectrum of Median Craniofacial Dysplasia PLASTIC AND RECONSTRUCTIVE SURGERY Allam, K. A., Wan, D. C., Kawamoto, H. K., Bradley, J. P., Sedano, H. O., Saied, S. 2011; 127 (2): 812-821

    Abstract

    Given the multiple permutations in craniofacial malformations, classification of median craniofacial dysplasia or midline Tessier no. 0 to 14 clefts has been difficult and disjointed. In this review, the authors present a summary of normal embryology, prior terminology, and their proposed new classification system. Median craniofacial dysplasia has tissue agenesis and holoprosencephaly at one end (the hypoplasias), frontonasal hyperplasia and excessive tissue (the hyperplasias) at the other end, and abnormal splitting or clefting and normal tissue volume (dysraphia) occupying the middle portion of the spectrum. These three distinct subclassifications have different forms of anomalies within their groups.

    View details for DOI 10.1097/PRS.0b013e318200aa08

    View details for Web of Science ID 000286928100040

    View details for PubMedID 21285785

  • Quality of Innervation in Sensate Medial Plantar Flaps for Heel Reconstruction PLASTIC AND RECONSTRUCTIVE SURGERY Wan, D. C., Gabbay, J., Levi, B., Boyd, J. B., Granzow, J. W. 2011; 127 (2): 723-730

    Abstract

    Reconstruction of the heel represents a difficult challenge for surgeons, given the demand for thick, durable skin capable of withstanding both pressure and shear. The authors describe the use of a sensate medial plantar flap for heel reconstruction in three patients and document the long-term retention of sensation compared with the contralateral uninjured heel and corresponding donor site.A medial plantar flap was harvested to include the branch of the medial plantar nerve to the instep to preserve innervation. Sharp pain, light and deep pressure, vibration, cold temperature, and static and dynamic two-point discrimination were examined between 6 months and 1 year after surgery.Sharp pain, vibration, and deep pressure sensation were present equally in the medial plantar flap, contralateral heel, and contralateral instep. Cold perception, light pressure, and static two-point and dynamic two-point discrimination were significantly less in the normal contralateral heel when compared with the heel reconstructed by the innervated flap. There were no significant differences in sensation between the medial plantar flap and the contralateral instep.The medial plantar flap is capable of providing durable, sensate coverage of plantar hindfoot defects with minimal donor-site morbidity. Furthermore, that sensation remains identical to that of the instep donor site and superior to that of the normal heel pad.

    View details for DOI 10.1097/PRS.0b013e3181fed76d

    View details for Web of Science ID 000286928100029

    View details for PubMedID 20966816

  • Differential Expression of Sclerostin in Adult and Juvenile Mouse Calvariae PLASTIC AND RECONSTRUCTIVE SURGERY Kwan, M. D., Quarto, N., Gupta, D. M., Slater, B. J., Wan, D. C., Longaker, M. T. 2011; 127 (2): 595-602

    Abstract

    An understanding of the molecular mechanisms controlling bone formation is central to skeletal tissue engineering efforts. The observation that immature animals are able to heal calvarial defects while adult animals are not has proven to be a useful tool for examining these mechanisms. Thus, the authors compared expression of sclerostin, a bone inhibitor, between the calvariae of juvenile and adult mice.Parietal bone was harvested from juvenile (6-day-old; n = 20) and adult (60-day-old; n = 20) mice. Sclerostin transcript and protein levels were compared between the parietal bone of juvenile and adult mice using polymerase chain reaction, Western blotting, and immunohistochemistry. Finally, osteoblasts from the parietal bone of juvenile and adult mice were harvested and cultured under osteogenic differentiation conditions with and without recombinant sclerostin (200 ng/ml). Terminal osteogenic differentiation was assessed at 21 days with alizarin red staining.Polymerase chain reaction, Western blot analysis, and immunohistochemistry all confirmed greater expression of sclerostin in the parietal bone of adult mice when compared with that of juvenile mice. Osteoblasts, whether from juvenile or adult parietal bones, demonstrated reduced capacity for osteogenic differentiation when exposed to recombinant sclerostin.Given the role of sclerostin in inhibiting bone formation, the authors' findings suggest that differences in expression levels of sclerostin may play a role in the differential regenerative capacity of calvariae from juvenile and adult animals. These findings suggest it as a potential target to abrogate in future tissue engineering studies.

    View details for DOI 10.1097/PRS.0b013e3181fed60d

    View details for Web of Science ID 000286928100014

    View details for PubMedID 21285764

  • Salvage of the Crucified Chin PLASTIC AND RECONSTRUCTIVE SURGERY Wan, D. C., Longaker, M. T., Allam, K. A., Perry, A., Kawamoto, H. K. 2011; 127 (1): 352-354

    View details for DOI 10.1097/PRS.0b013e3181fad3d6

    View details for Web of Science ID 000285992100048

    View details for PubMedID 21200230

  • Correction of Large Facial Encephalocele With Bilateral Rare Craniofacial Clefts JOURNAL OF CRANIOFACIAL SURGERY Wan, D. C., Lazareff, J. A., Jarrahy, R., Bradley, J. P. 2011; 22 (1): 338-342

    Abstract

    Treatment of Tessier number 3, 11 craniofacial clefts represent a surgical challenge with complex bone and soft tissue deficits of the lip, cheek, medial orbit, and forehead. The severity of the presenting defect will ultimately determine the number of reconstructive stages required as well as the timing of each stage. Initial surgery in infancy is aimed at functional correction. We present the case of a patient with an expanding fronto-orbital encephalocele, a right number 3, 11 cleft and a left number 3, 10 cleft. The initial procedure repaired the encephalocele and reconstructed the supraorbital and forehead regions. Subsequent surgeries corrected the bilateral facial clefts with cleft lip repair, rotation of the forehead and nasal unit, cheek advancement, and a lower eyelid transposition flap.

    View details for DOI 10.1097/SCS.0b013e3181f7e0fb

    View details for Web of Science ID 000286195600080

    View details for PubMedID 21239931

  • Deformational Plagiocephaly: A Look Into the Future JOURNAL OF CRANIOFACIAL SURGERY Levi, B., Wan, D. C., Longaker, M. T., Habal, M. B. 2011; 22 (1): 3-5

    View details for DOI 10.1097/SCS.0b013e3181fb7ee5

    View details for Web of Science ID 000286195600002

    View details for PubMedID 21239916

  • Gradual Orbital Contraction after Facial Bipartition: Correction of Wide No. 0 to 14 Craniofacial Cleft PLASTIC AND RECONSTRUCTIVE SURGERY Wan, D. C., Tanna, N., Allam, K. A., Perry, A., Bradley, J. P. 2010; 126 (6): 2109-2112

    View details for DOI 10.1097/PRS.0b013e3181f44802

    View details for Web of Science ID 000284832400060

    View details for PubMedID 21124151

  • Depot-Specific Variation in the Osteogenic and Adipogenic Potential of Human Adipose-Derived Stromal Cells PLASTIC AND RECONSTRUCTIVE SURGERY Levi, B., James, A. W., Glotzbach, J. P., Wan, D. C., Commons, G. W., Longaker, M. T. 2010; 126 (3): 822-834

    Abstract

    Adipose-derived stromal cells hold promise for use in tissue regeneration. However, multiple facets of their biology remain unclear. The authors examined the variations in osteogenesis and adipogenesis in adipose-derived stromal cells between subcutaneous fat depots and potential molecular causes.Adipose-derived stromal cells were isolated from human patients from subcutaneous fat depots, including arm, flank, thigh, and abdomen (n = 5 patients). Osteogenic and adipogenic differentiation was performed (alkaline phosphatase, alizarin red, and oil red O staining, and quantitative real-time polymerase chain reaction). Co-cultures were established to assess the paracrine effect of human adipose-derived stromal cells on mouse osteoblasts. Finally, HOX gene expression was analyzed by quantitative real-time polymerase chain reaction.Subcutaneous fat depots retain markedly different osteogenic and adipogenic potentials. Osteogenesis was most robust in adipose-derived stromal cells from the flank and thigh, as compared with those from the arm and abdomen (p < 0.05 by all markers examined). This was accompanied by elevations of BMP4 and BMPR1B (p < 0.05 by all markers examined). The osteogenic advantage of cells from the flank and thigh was again observed when analyzing the paracrine effects of these cells. Conversely, those cells isolated from the flank had a lesser ability to undergo adipogenic differentiation. Adipose-associated HOX genes were less expressed in flank-derived adipose-derived stromal cells.Variations exist between fat depots in terms of adipose-derived stromal cell osteogenic and adipogenic differentiation. Differences in HOX expression and bone morphogenetic protein signaling may underlie these observations. This study indicates that the choice of fat depot derivation of adipose-derived stromal cells may be an important one for future efforts in tissue engineering.

    View details for DOI 10.1097/PRS.0b013e3181e5f892

    View details for Web of Science ID 000281606700011

    View details for PubMedID 20811215

  • Inclusion of Mesh in Donor-Site Repair of Free TRAM and Muscle-Sparing Free TRAM Flaps Yields Rates of Abdominal Complications Comparable to Those of DIEP Flap Reconstruction PLASTIC AND RECONSTRUCTIVE SURGERY Wan, D. C., Tseng, C. Y., Anderson-Dam, J., Dalio, A. L., Crisera, C. A., Festekjian, J. H. 2010; 126 (2): 367-374

    Abstract

    Pedicled and free transverse rectus abdominis musculocutaneous (TRAM) flaps remain popular for autologous breast reconstruction, but the incidence of abdominal donor-site bulge and hernia is significantly greater when compared with deep inferior epigastric artery perforator (DIEP) flap reconstruction. Mesh repair after muscle harvest, however, may reduce the complication rate to that observed with perforator flaps alone.A retrospective review of all free flap breast reconstructions at the University of California, Los Angeles Medical Center from 2002 to 2007 was performed. Abdominal bulge and hernia were noted for patients undergoing free TRAM and muscle-sparing free TRAM flap reconstructions and were compared with those observed following DIEP flap reconstructions.A total of 275 free TRAM plus muscle-sparing free TRAM flaps and 200 DIEP flaps were performed. Among patients with free and muscle-sparing free TRAM flaps, 11.3 percent were found to have postoperative abdominal bulge or hernia. Only 3.5 percent of DIEP flap patients had abdominal complications. Incorporating mesh into the rectus fascia repair significantly reduced the abdominal complications reported to 5.1 percent. Of the 86 free and muscle-sparing free TRAM flaps that were bilateral, 12.8 percent had hernias/bulges. Use of mesh with bilateral free and muscle-sparing free TRAM flaps reduced the complication rate to 3.7 percent.Incorporating mesh into rectus fascia repair in free and muscle-sparing free TRAM flap cases significantly reduces the rate of postoperative abdominal complications to levels equivalent to those for DIEP flap reconstructions. The authors advocate deciding intraoperatively between DIEP and muscle-sparing free TRAM flap dissections based on ease of dissection and whichever offers optimal safety and flap perfusion. Routine use of mesh in donor-site repair will decrease postoperative abdominal morbidity in unilateral and bilateral cases.

    View details for DOI 10.1097/PRS.0b013e3181de1b7e

    View details for Web of Science ID 000280143800004

    View details for PubMedID 20679822

  • Regulation of Human Adipose-Derived Stromal Cell Osteogenic Differentiation by Insulin-Like Growth Factor-1 and Platelet-Derived Growth Factor-alpha PLASTIC AND RECONSTRUCTIVE SURGERY Levi, B., James, A. W., Wan, D. C., Glotzbach, J. P., Commons, G. W., Longaker, M. T. 2010; 126 (1): 41-52

    Abstract

    Human adipose-derived stromal cells possess a great potential for tissue engineering purposes. The authors' laboratory is interested in harnessing human adipose-derived stromal cells for skeletal tissue regeneration and identifying those factors that enhance human adipose-derived stromal cell osteogenic differentiation. The authors hypothesized that insulin-like growth factor (IGF) and platelet-derived growth factor (PDGF) would stimulate human adipose-derived stromal cell osteogenesis and that IGF would stimulate adipogenesis.Adipose-derived stromal cells were harvested from human lipoaspirate. Previously, a microarray analysis examined gene expression throughout osteogenic differentiation. In a candidate fashion, the authors added recombinant IGF-1 and PDGF-alpha individually and in combination. Osteogenesis and adipogenesis were assessed by alkaline phosphatase, alizarin red, and oil red O staining, and quantitative real-time polymerase chain reaction (RUNX2, ALP, OCN, IGF1, PPARG, LPL, AP2, and GCP1). Finally, intersection between IGF and PDGF signaling pathways was evaluated.IGF-1 was observed to increase osteogenic differentiation by all markers (p < 0.01). However, PDGF-alpha when added alone primarily did not affect osteogenic markers. PDGF-alpha positively regulated transcription of IGF1. Addition of PDGF-alpha in combination with or before IGF-1 enhanced osteogenesis more than either alone. IGF-1 increased whereas PDGF-alpha diminished human adipose-derived stromal cell adipogenesis.IGF signaling significantly increased osteogenesis in human adipose-derived stromal cells and may be used for tissue-engineering purposes. The combination of PDGF and IGF may be more beneficial than either alone in driving adipose-derived stromal cell osteogenesis. Future in vivo applications will focus on the combination of adipose-derived stromal cells, biomimetic scaffolds, and recombinant IGF.

    View details for DOI 10.1097/PRS.0b013e3181da8858

    View details for Web of Science ID 000279097500006

    View details for PubMedID 20220555

  • Origin Matters: Differences in Embryonic Tissue Origin and Wnt Signaling Determine the Osteogenic Potential and Healing Capacity of Frontal and Parietal Calvarial Bones JOURNAL OF BONE AND MINERAL RESEARCH Quarto, N., Wan, D. C., Kwan, M. D., Panetta, N. J., Li, S., Longaker, M. T. 2010; 25 (7): 1680-1694

    Abstract

    Calvarial bones arise from two embryonic tissues, namely, the neural crest and the mesoderm. In this study we have addressed the important question of whether disparate embryonic tissue origins impart variable osteogenic potential and regenerative capacity to calvarial bones, as well as what the underlying molecular mechanism(s). Thus, by performing in vitro and in vivo studies, we have investigated whether differences exist between neural crest-derived frontal and paraxial mesodermal-derived parietal bone. Of interest, our data indicate that calvarial bone osteoblasts of neural crest origin have superior potential for osteogenic differentiation. Furthermore, neural crest-derived frontal bone displays a superior capacity to undergo osseous healing compared with calvarial bone of paraxial mesoderm origin. Our study identified both in vitro and in vivo enhanced endogenous canonical Wnt signaling in frontal bone compared with parietal bone. In addition, we demonstrate that constitutive activation of canonical Wnt signaling in paraxial mesodermal-derived parietal osteoblasts mimics the osteogenic potential of frontal osteoblasts, whereas knockdown of canonical Wnt signaling dramatically impairs the greater osteogenic potential of neural crest-derived frontal osteoblasts. Moreover, fibroblast growth factor 2 (FGF-2) treatment induces phosphorylation of GSK-3beta and increases the nuclear levels of beta-catenin in osteoblasts, suggesting that enhanced activation of Wnt signaling might be mediated by FGF. Taken together, our data provide compelling evidence that indeed embryonic tissue origin makes a difference and that active canonical Wnt signaling plays a major role in contributing to the superior intrinsic osteogenic potential and tissue regeneration observed in neural crest-derived frontal bone.

    View details for DOI 10.1359/jbmr.091116

    View details for Web of Science ID 000280395900023

    View details for PubMedID 19929441

  • Elucidating Mechanisms of Osteogenesis in Human Adipose-Derived Stromal Cells via Microarray Analysis JOURNAL OF CRANIOFACIAL SURGERY Lee, J., Gupta, D., Panetta, N. J., Levi, B., James, A. W., Wan, D., Commons, G. W., Longaker, M. T. 2010; 21 (4): 1136-1141

    Abstract

    The osteogenic potential of human adipose-derived stromal cells (hASCs), the ease of cell procurement, and the shortcomings of conventional skeletal reconstruction call for further analysis of the molecular mechanisms governing hASC osteogenic differentiation. We have examined the expression profile of the human transcriptome during osteogenic differentiation of ASCs using microarray. Subsequently, we analyzed those genes related to osteogenesis that have not been previously studied about hASCs. We have preliminarily assessed the role of IGFBP3, TGF-B3, TNC, CTGF, DKK-1, and PDGFRB in hASC osteogenic differentiation.We compared the expression profile of undifferentiated hASCs to that of hASCs treated with osteogenic differentiation medium for 1, 3, or 7 days using the Human Exonic Evidence-Based Oligonucleotide chip. Genes significantly overexpress or underexpressed were validated with quantitative reverse transcription-polymerase chain reaction. The osteogenic capability of ASCs was verified by Alizarin Red staining.IGFBP3, TGF-B3, TNC, CTGF, and PDGFRB were all upregulated in early osteogenesis, and TGF-B3, TNC, and PDGFRB were upregulated in late osteogenesis by microarray and quantitative reverse transcription analysis. In contrast, DKK-1 was downregulated in early and late osteogenesis. Alizarin Red staining showed a significant increase in mineralization in hASCs, even after 1 day in osteogenic differentiation medium.Factors that commit hASCs to an osteogenic pathway remain largely unknown. We have described 6 genes that play key roles in hASC osteogenic differentiation. We plan to further exploit these data via in vitro treatment of hASCs with these soluble cytokines and in vivo translation using a nude mouse calvarial defect model.

    View details for DOI 10.1097/SCS.0b013e3181e488d6

    View details for Web of Science ID 000280149100044

    View details for PubMedID 20613589

  • Amelioration of Acquired Nasopharyngeal Stenosis, with Bilateral Z-Pharyngoplasty ANNALS OF PLASTIC SURGERY Wan, D. C., Kumar, A., Head, C. S., Katchikian, H., Bradley, J. P. 2010; 64 (6): 747-750

    Abstract

    Nasopharyngeal stenosis as a postoperative complication following pharyngeal surgery (tonsillectomy/adenoidectomy) is rare and may be difficult to treat. All patients with severe nasopharyngeal stenosis treated at UCLA with a bilateral Z-pharyngoplasty procedure from 1999 to 2006 were studied (n = 6). Degree of pharyngeal stenosis preoperatively and following a bilateral Z-pharyngoplasty was graded 0-4 based on (1) symptomatology (snoring, hyponasal speech, difficulty with nasal breathing, difficulty breathing during exercise, obstructive sleep apnea, daytime fatigue, anosmia, rhinorrea, dysphagia, or difficulty in blowing nose) and (2) measurement of stricture at the time of direct nasolaryngoscopy. Nasopharyngeal stenosis after pharyngeal surgery (adenotonsillectomy--67%, uvuloplasty--17%, pharyngoplasty--17%) failed to be alleviated by a mean of 2.3 procedures (kenalog injection or scar excision) and required corrective bilateral Z-pharyngoplasty a mean of 9.2 months after the original surgery. Symptomatic grading of the nasopharyngeal stenosis improved from a mean score of 3.3 (severe stenosis) preoperatively to a score of 0.2 (minimal to no stenosis) in follow-up. Endoscopic stricture measurement improved from 6.1 x 6.3 mm preoperatively to 28.1 x 39.3 mm in follow-up. Bilateral Z-pharyngoplasty was effective in alleviating severe postsurgical nasopharyngeal stenosis.

    View details for DOI 10.1097/SAP.0b013e3181a73009

    View details for Web of Science ID 000278116900012

    View details for PubMedID 20489403

  • Marjolin Ulcer in Hidradenitis Suppurativa Case Reports ANNALS OF PLASTIC SURGERY Grewal, N. S., Wan, D. C., Roostaeian, J., Rubayi, S. R. 2010; 64 (3): 315-317

    Abstract

    Hidradenitis suppurativa is a chronic, recurrent, inflammatory disease of apocrine gland-bearing skin areas. Long-standing low-grade infection and chronic abscess formation result in ulcers, fistulas, and progressive scars. A rare complication is the development of squamous cell carcinoma, known as Marjolin ulcer. We report 3 cases in which squamous cell carcinoma developed despite medical treatments and local excisions. Because of the poor prognosis associated with squamous cell carcinoma, we advocate wide excision of hidradenitis suppurativa lesions when other treatments have failed.

    View details for DOI 10.1097/SAP.0b013e3181a7302a

    View details for Web of Science ID 000275061800013

    View details for PubMedID 20179481

  • Human Adipose-Derived Stromal Cells Respond to and Elaborate Bone Morphogenetic Protein-2 during In Vitro Osteogenic Differentiation PLASTIC AND RECONSTRUCTIVE SURGERY Panetta, N. J., Gupta, D. M., Lee, J. K., Wan, D. C., Commons, G. W., Longaker, M. T. 2010; 125 (2): 483-493

    Abstract

    Interest in the potential application of adipose-derived stromal cells in cell-mediated tissue engineering of bone and other mesenchymal-derived tissues is growing. This study aimed to investigate the hypothesis that human adipose-derived stromal cells respond to and elaborate bone morphogenetic protein (BMP) 2, which could represent an important target of molecular manipulation to enhance the osteogenic potential of human adipose-derived stromal cells.Human adipose-derived stromal cells were differentiated for 10 days toward the osteogenic lineage in osteogenic differentiation media alone or supplemented with recombinant human BMP2 (rhBMP2). Alizarin red staining was quantified by spectrophotometry. Gene expression analyses were performed using quantitative real-time polymerase chain reaction. BMP2 levels in conditioned media were titered by enzyme-linked immunosorbent assay daily during osteogenic differentiation. Human adipose-derived stromal cells were cultured in complete or partially (50 percent) changed osteogenic differentiation media, or unchanged osteogenic differentiation media, to assay for pro-osteogenic secreted factors. In addition, human adipose-derived stromal cells were cultured in osteogenic differentiation media supplemented with BMP2/BMP4-neutralizing antibody.Exogenous rhBMP2 significantly augmented the in vitro osteogenic potential of human adipose-derived stromal cells in a dose-dependent fashion, and significantly increased transcript levels of RUNX2 and osteocalcin. BMP2, BMP4, BMPR1B, and SMAD1/5 expression was significantly increased during differentiation. Enzyme-linked immunosorbent assay demonstrated significantly increased BMP2 elaboration during differentiation. Culture in conditioned osteogenic differentiation media led to significantly increased matrix mineralization. Mineralization was significantly decreased when osteogenic differentiation media was supplemented with a BMP2/BMP4-neutralizing antibody.These data strongly support that BMP signaling is dynamic and important during normal in vitro osteogenic differentiation of human adipose-derived stromal cells. Thus, BMP2 may be used to enhance the osteogenic differentiation of human adipose-derived stromal cells for bone tissue engineering. Future studies will examine the effect of rhBMP2 on osteogenic differentiation of human adipose-derived stromal cells in vivo.

    View details for DOI 10.1097/PRS.0b013e3181c82d75

    View details for Web of Science ID 000274741700008

    View details for PubMedID 20124834

  • Craniofacial surgery, from past pioneers to future promise. Journal of maxillofacial and oral surgery Wan, D. C., Kwan, M. D., Kumar, A., Bradley, J. P., Longaker, M. T. 2009; 8 (4): 348-356

    Abstract

    As a surgical subspecialty devoted to restoration of normal facial and calvarial anatomy, craniofacial surgeons must navigate the balance between pathologic states of bone excess and bone deficit. While current techniques employed take root in lessons learned from the success and failure of early pioneers, craniofacial surgery continues to evolve, and novel modalities will undoubtedly arise integrating past and present experiences with future promise to effectively treat craniofacial disorders.This review provides an overview of current approaches in craniofacial surgery for treating states of bone excess and deficit, recent advances in our understanding of the molecular and cellular processes underlying craniosynostosis, a pathological state of bone excess, and current research efforts in cellular-based therapies for bone regeneration.The surgical treatment of bone excess and deficit has evolved to improve both the functional and morphological outcomes of affected patients. Recent progress in elucidating the molecular and cellular mechanisms governing bone formation will be instrumental for developing improved therapies for the treatment of pathological states of bone excess and deficit.While significant advances have been achieved in craniofacial surgery, improved strategies for addressing states of bone excess and bone deficit in the craniofacial region are needed. Investigations on the biomolecular events involved in craniosynostosis and cellular-based bone tissue engineering may soon be added to the armamentarium of surgeons treating craniofacial dysmorphologies.

    View details for DOI 10.1007/s12663-009-0084-x

    View details for PubMedID 23139542

  • Tissue Harvest by Means of Suction-Assisted or Third-Generation Ultrasound-Assisted Lipoaspiration Has No Effect on Osteogenic Potential of Human Adipose-Derived Stromal Cells PLASTIC AND RECONSTRUCTIVE SURGERY Panetta, N. J., Gupta, D. M., Kwan, M. D., Wan, D. C., Commons, G. W., Longaker, M. T. 2009; 124 (1): 65-73

    Abstract

    Human adipose-derived stromal cells readily undergo osteogenic differentiation in vitro and in vivo. Thus, interest in their potential role in skeletal tissue engineering continues to escalate. Very little is known regarding the effects that energy delivered by means of third-generation ultrasound-assisted lipoaspiration may have on the osteogenic potential of these cells. The authors investigated whether differences in adipose-derived stromal cell yield, and the in vitro proliferation and osteogenic potential of these cells obtained by suction-assisted lipoaspiration or third-generation ultrasound-assisted lipoaspiration, exist.Adipose-derived stromal cells were harvested from lipoaspiration specimens of patients undergoing elective suction-assisted lipoaspiration and third-generation ultrasound-assisted lipoaspiration. Harvested cells were seeded to evaluate proliferative capacity and in vitro osteogenic potential. Alkaline phosphatase and alizarin red staining were performed to evaluate early and terminal osteogenic differentiation, respectively. Quantitative real-time polymerase chain reaction analysis was used to examine osteogenic gene expression patterns of RUNX2/CFBA1 (early differentiation) and osteocalcin (late differentiation).No significant differences in the proliferative capacity (n = 3), alkaline phosphatase staining (n = 3), or extracellular matrix mineralization (n = 3) of suction-assisted lipoaspiration- or third-generation ultrasound-assisted lipoaspiration-derived cells were appreciated. Transcript levels of markers of early and terminal osteogenic differentiation were not significantly different (n = 3).These findings suggest that exposure of adipose-derived stromal cells to ultrasound energy during tissue harvest by means of third-generation ultrasound-assisted lipoaspiration does not impart a negative consequence toward their proliferative capacity or osteogenic potential. Thus, the cells harvested using third-generation ultrasound-assisted lipoaspiration are comparable to those obtained by means of suction-assisted lipoaspiration for use in the study of osteogenic differentiation and skeletal tissue engineering.

    View details for DOI 10.1097/PRS.0b013e3181ab10cd

    View details for Web of Science ID 000267895000011

    View details for PubMedID 19568046

  • Craniofacial Autologous Fat Transfer JOURNAL OF CRANIOFACIAL SURGERY Wan, D. C., Lim, A. T., Longaker, M. T. 2009; 20 (2): 273-274

    View details for DOI 10.1097/SCS.0b013e31819921d3

    View details for Web of Science ID 000264570300003

    View details for PubMedID 19305242

  • Taz is a transcriptional modulator of human adipose-derived stromal cell differentiation towards the osteogenic lineage CRANIOFACIAL SURGERY 13: PROCEEDINGS OF THE THIRTEEN CONGRESS OF THE INTERNATIONAL SOCIETY OF CRANIOFACIAL SURGERY AND PARIS DISTRACTION SYMPOSIUM Gupta, D. M., Panetta, N. J., Vial, I. N., Lee, J. K., Wan, D. C., Gurtner, G. C., Longaker, M. T. 2009: 87-89
  • Human adipose-derived stromal cells elaborate and respond to bone morphogenetic protein-2 (bmp-2) during in vitro osteogenic differentiation CRANIOFACIAL SURGERY 13: PROCEEDINGS OF THE THIRTEEN CONGRESS OF THE INTERNATIONAL SOCIETY OF CRANIOFACIAL SURGERY AND PARIS DISTRACTION SYMPOSIUM Gupta, D. M., Panetta, N. J., Wan, D. C., Commons, G. W., Longaker, M. T. 2009: 79-81
  • Tissue-harvest procedure has no effect on adipose-derived stromal cell-mediated bone tissue engineering in vitro CRANIOFACIAL SURGERY 13: PROCEEDINGS OF THE THIRTEEN CONGRESS OF THE INTERNATIONAL SOCIETY OF CRANIOFACIAL SURGERY AND PARIS DISTRACTION SYMPOSIUM Panetta, N. J., Gupta, D. M., Kwan, M. D., Wan, D. C., Commons, G. W., Longaker, M. T. 2009: 163-165
  • Global age-dependent differences in gene expression in response to calvarial injuryd JOURNAL OF CRANIOFACIAL SURGERY Wan, D. C., Kwan, M. D., Gupta, D. M., Wang, Z., Slater, B. J., Panetta, N. J., Morrell, N. T., Longaker, M. T. 2008; 19 (5): 1292-1301

    Abstract

    Children less than 2 years of age are capable of healing large calvarial defects, whereas adults have been found to lack this endogenous ability. In this study, we used microarray analysis to compare genomewide expression patterns during active regeneration after injury with calvaria in skeletally immature and mature mice. Parietal bone defects were created in 6-day-old (juvenile) and 60-day-old (adult) mice using a 4-mm trephine bit (n = 20 mice per age group). The calvarial disc was removed, leaving the underlying dura mater intact. Two weeks after injury, the region of regeneration with the underlying dura mater was harvested, and RNA was extracted for microarray analysis. The 25 most differentially upregulated genes in juvenile regenerates compared with adults were listed, as well as selected bone-related genes. In addition, QRT-PCR confirmation of specific genes was performed for validation. Juvenile regenerates expressed significantly greater amounts of BMP-2, -4, -7, as well as FGF-2 and its receptor FGFR-1. Various other growth factors were also noted to be upregulated, including IGF-2 and Ptn. This corresponded with the increased expression of markers for osteogenic differentiation of Sparc and Oc. Markers of osteoclast activity, Acp5, Ctsk, and Mmp2, were noted to be greater in juvenile regenerates compared with adults. The observation of Mmp14 upregulation, however, highlights the importance of balanced osteoclast-mediated bone resorption for ultimate healing. The 2 most differentially regulated genes, transthyretin (Ttr) and prostaglandin D2 synthase (Ptgds), highlight the potential role of retinoic acid signaling and the prostaglandin axis on skeletal regeneration. These findings underscore the multitude of biomolecular mechanisms at play, allowing juvenile calvaria to heal after injury. The identification of various growth factors and cytokines involved also suggests novel therapeutic strategies for tissue-engineering purposes.

    View details for Web of Science ID 000259503400015

    View details for PubMedID 18812854

  • Microarray analysis of the role of regional dura mater in cranial suture fate PLASTIC AND RECONSTRUCTIVE SURGERY Kwan, M. D., Wan, D. C., Wang, Z., Gupta, D. M., Slater, B. J., Longaker, M. T. 2008; 122 (2): 389-399

    Abstract

    Craniosynostosis, the premature fusion of cranial sutures, results in serious neurologic and morphologic abnormalities when left untreated. Surgical excision of the fused sutures and remodeling of the skull remains the standard therapy. Development of novel, minimally invasive therapies for craniosynostosis will undoubtedly be dependent on a more thorough understanding of the molecular mechanisms underlying this abnormality. Significant evidence suggests the influence of regional dura mater on the behavior of the overlying suture complex. The mouse model has been instrumental in investigating this observation because of the natural juxtaposition of the posterior frontal suture, which fuses early in life, with the other cranial sutures, which remain patent.The authors used microarray analysis to compare genomic changes in the dura mater underlying the posterior frontal and sagittal sutures of mice. Suture-associated dura mater was harvested from mice before (postnatal day 5), during (postnatal day 10), and after (postnatal day 20) posterior frontal suture fusion (n = 20 mice for each of the three time points).Microarray results confirmed differential regulation of genes involved in paracrine signaling, extracellular matrix, and bone remodeling between the dura mater underlying the fusing posterior frontal suture and the patent sagittal suture.These data confirm global differences in gene expression between regional dura mater underlying fusing and patent sutures. These results provide further insight into potential molecular mechanisms that may play a role in cranial suture biology.

    View details for DOI 10.1097/PRS.0b013e31817d6244

    View details for Web of Science ID 000258136900008

    View details for PubMedID 18626354

  • Dissecting the influence of regional dura mater on cranial suture biology PLASTIC AND RECONSTRUCTIVE SURGERY Slater, B. J., Kwan, M. D., Gupta, D. M., Amasha, R. R., Wan, D. C., Longaker, M. T. 2008; 122 (1): 77-84

    Abstract

    Craniosynostosis is a relatively common developmental disorder that leads to a number of serious consequences. Previous studies have shown the influence of dura mater on the overlying cranial suture. This study was conducted to determine the role of regional dura mater versus the intrinsic nature of the suture in directing the overlying suture's fate.The authors examined the effect of regional dura mater on the fate and morphology of the posterofrontal and coronal sutures. In 8-day-old Sprague-Dawley rats, calvarial disks, consisting of the posterofrontal and coronal sutures, were excised and placed in one of three positions: (1) native position (control group), (2) rotated 45 degrees, or (3) rotated 90 degrees (n = 5 animals per group). The animals were euthanized 1 month postoperatively, and the sutures were analyzed histologically.The control group revealed normal suture morphology (n = 5). In the 45-degree rotation group, which placed the posterofrontal and coronal sutures over non-suture-associated dura mater, the posterofrontal sutures fused with thin morphology, and the coronal sutures remained patent (n = 5). In the 90-degree rotation group, the posterofrontal sutures, which were positioned over coronal suture-associated dura mater, were found to be fused with thinner morphology. The coronal sutures of the 90-degree rotation group, which were placed over posterofrontal suture-associated dura mater, remained patent but had acquired a posterofrontal-like morphology (n = 5).This study further elucidates variations in the biology of dura mater, depending on its location. Furthermore, these results illustrate the interplay between regional dura mater and the inherent characteristics of the suture complex in determining suture biology.

    View details for DOI 10.1097/PRS.0b013e318177478c

    View details for Web of Science ID 000257104300008

    View details for PubMedID 18594389

  • Testicular carcinoma presenting as cutaneous nasal metastasis: Case report and review of the literature BRITISH JOURNAL OF ORAL & MAXILLOFACIAL SURGERY Gleizal, A., Torossian, J. M., Wan, D. C., Beziat, J. 2008; 46 (5): 416-418

    Abstract

    Testicular choriocarcinoma is a highly malignant germ cell neoplasm, which metastasises to lungs, and brain. Spread to the skin, however, is rare, with only 11 cases reported to our knowledge. This is the second reported case of a skin metastasis of choriocarcinoma to the head and neck, and the third in which a cutaneous metastasis was the first finding at initial presentation. A review of published reports showed that it had been described as individual firm, reddish or violaceous subcutaneous nodules with typical histological features.

    View details for DOI 10.1016/j.bjoms.2007.10.006

    View details for Web of Science ID 000257639900019

    View details for PubMedID 18155815

  • Molecular mechanisms of FGF-2 inhibitory activity in the osteogenic context of mouse adipose-derived stem cells (mASCs) BONE Quarto, N., Wan, D. C., Longaker, M. T. 2008; 42 (6): 1040-1052

    Abstract

    Adipose-derived adult stem cells (ASCs), like their bone-marrow derived counterparts, possess the ability to differentiate down osteogenic, chondrogenic, adipogenic, and myogenic pathways. For bone differentiation of mouse ASCs (mASCs), retinoic-acid mediated upregulation of BMPR-IB has been found to be necessary. Interestingly, our previous work has also shown Fibroblast Growth Factor-2 (FGF-2) to strongly inhibit this osteogenic differentiation, even in the presence of retinoic acid. In this report, we investigated the molecular mechanisms underlying FGF-2 mediated osteogenic inhibition, demonstrating that addition of exogenous FGF-2 to mASCs antagonizes upregulation of BMPR-IB gene expression in response to retinoic acid. In addition, constitutive expression of BMPR-IB, but not BMPR-IA or BMPR-II, was found to counteract the inhibitory effects of FGF-2. Finally, p53(-/-) mASCs and human ASCs, both of which express high levels of endogenous BMPR-IB, underwent normal osteogenic differentiation even in the presence of FGF-2. Collectively, our data therefore indicate that FGF-2 antagonizes the response of mASCs to retinoic acid and also suggest that threshold levels of BMPR-IB may play a crucial role both in counteracting the inhibitory role of FGF-2 and in promoting osteogenic differentiation of ASCs in the absence of retinoic acid. Moreover, the present study also indicates that differences exist between mouse and human ASCs in relationship to FGF-2 activity in the osteogenic context.

    View details for DOI 10.1016/j.bone.2008.01.026

    View details for Web of Science ID 000256330000006

    View details for PubMedID 18420480

  • Cell-based therapies for skeletal regenerative medicine HUMAN MOLECULAR GENETICS Kwan, M. D., Slater, B. J., Wan, D. C., Longaker, M. T. 2008; 17: R93-R98

    Abstract

    Skeletal deficits represent a substantial biomedical burden on the US healthcare system. Current strategies for reconstructing bony defects are fraught with inadequacies. Cell-based therapies for skeletal regeneration offer a paradigm shift that may provide alternative solutions. Substantial work has identified a host of cellular sources that possess the potential for osteogenic differentiation. Significant efforts have been devoted toward characterizing the role of postnatal cellular sources that are relatively abundant and easily accessible. Among these, the potential of using adipose-derived stromal cells for skeletal regeneration has garnered much interest. Integral to these efforts directed at characterizing cellular sources are studies that seek to understand the factors that initiate and regulate osteogenic differentiation of progenitor cells. Specifically, focus has been directed on elucidating the role of bone morphogenetic protein and fibroblast growth factor signaling in regulating osteogenic differentiation of osteoprogenitor cells. Concurrent studies in the field of scaffold design have also helped to advance the potential for cell-based therapies.

    View details for DOI 10.1093/hmg/ddn071

    View details for Web of Science ID 000258261600015

    View details for PubMedID 18632703

  • Cranial Sutures: A Brief Review PLASTIC AND RECONSTRUCTIVE SURGERY Slater, B. J., Lenton, K. A., Kwan, M. D., Gupta, D. M., Wan, D. C., Longaker, M. T. 2008; 121 (4): 170E-178E

    Abstract

    Craniosynostosis, or the premature fusion of one or more cranial sutures, is a relatively common congenital defect that causes a number of morphologic and functional abnormalities. With advances in genetics and molecular biology, research of craniosynostosis has progressed from describing gross abnormalities to understanding the molecular interactions that underlie these cranial deformities. Animal models have been extremely valuable in improving our comprehension of human craniofacial morphogenesis, primarily by human genetic linkage analysis and the development of knock-out animals. This article provides a brief review of perisutural tissue interactions, embryonic origins, signaling molecules and their receptors, and transcription factors in maintaining the delicate balance between proliferation and differentiation of cells within the suture complex that determines suture fate. Finally, this article discusses the potential implications for developing novel therapies for craniosynostosis.

    View details for DOI 10.1097/01.prs.0000304441.99483.97

    View details for Web of Science ID 000207666900003

    View details for PubMedID 18349596

  • Myoplasty for congenital macrostomia CLEFT PALATE-CRANIOFACIAL JOURNAL Gleizal, A., Wan, D. C., Kwan, M. D., Beziat, J. 2008; 45 (2): 179-186

    Abstract

    To describe the different myoplasty techniques that could be used for limited commissural reconstruction.Twelve cases of congenital macrostomia are reported, with different cleft lengths and termination sites. For each case, an orbicular myoplasty was performed, and in the case of extension to the area of the tragus or tonsillar pillars, a masseteric myoplasty or pharyngoplasty was performed. Functional and aesthetic results were analyzed.Functional results were excellent, with normal phonation, facial expression, and deglutition in the case of posterior extension. Aesthetic results were good, with only two cases of skin fasciculation during facial movement.Myoplasty in macrostomia could be limited to an orbicular reorientation in the case of a short cleft or can include a masseteric myoplasty or pharnygoplasty should the cleft extend further. Analyzing 90 reported cases of congenital macrostomia in the world literature, an important point has emerged. In some cases, the cleft could continue sagittally to the tonsillar pillars or laterally, distal to the anterior border of the masseter, to the region of the tragus. Repair in these cases requires reconstruction of the tonsillar pillars and masseteric repair in addition to orbicular removal. No reports in the world literature have referred to these other myoplasties that could be necessary, even if such pathology is very rare. In addition, no classification of congenital macrostomia was found in the world literature. We therefore propose a surgical classification of macrostomia relative to the nature of myoplasty required.

    View details for DOI 10.1597/05-190.1

    View details for Web of Science ID 000254373500009

    View details for PubMedID 18333640

  • Current treatment of craniosynostosis and future therapeutic directions. Frontiers of oral biology Wan, D. C., Kwan, M. D., Lorenz, H. P., Longaker, M. T. 2008; 12: 209-230

    Abstract

    Normal craniofacial development is contingent upon coordinated growth between the brain and overlying calvaria. Craniosynostosis, the premature fusion of one or more cranial sutures, perturbs this natural framework, resulting in dramatic dysmorphology of the skull and face along with a multitude of associated functional abnormalities. Traditional approaches to the treatment of craniosynostosis have employed complex surgical remodeling of the skull vault and facial deformities all aimed at increasing the amount of intracranial volume and restoring a more normal craniofacial appearance. Significant morbidity and mortality, however, have plagued these procedures, driving dramatic evolution in our approach towards the treatment of pathologically fused sutures. Recent clinical and genetic studies have identified multiple forms of human craniosynostosis, each associated with mutations within various cytokine signaling pathways. Knowledge garnered from these investigations bear promise for the future development of alternative strategies to enhance or perhaps even replace contemporary approaches for the treatment of craniosynostosis.

    View details for DOI 10.1159/0000115043

    View details for PubMedID 18391503

  • Applications of an athymic nude mouse model of nonhealing critical-sized calvarial defects JOURNAL OF CRANIOFACIAL SURGERY Gupta, D. M., Kwan, M. D., Slater, B. J., Wan, D. C., Longaker, M. T. 2008; 19 (1): 192-197

    Abstract

    Calvarial bone defects are a common clinical scenario in craniofacial surgery. Numerous approaches are used to reconstruct skull defects, and each possesses its own inherent disadvantages. This fact underscores the opportunity to develop a novel method to repair osseous defects in craniofacial surgery. Recent literature strongly suggests that cell-based therapies in the form of regenerative medicine may be a developing paradigm in reconstructive surgery. Although numerous studies have probed osteoprogenitor cells from mice, few have explored the biology of human cells in the setting of osteogenesis in an equally rigorous manner. This study proposes a nude mouse model of critical-sized calvarial defects to study the in vivo biology of human osteoprogenitor cells. Critical-sized 4.0-mm calvarial defects were created in nude mice (n = 15) with a custom trephine drill bit outfitted to a dental drill handpiece. During the craniotomy, the dura mater was spared from injury. Gross inspection, routine histology, and micro-computed tomographic scanning were performed at 2, 4, 8, and 16 weeks postoperatively. There was no calvarial healing in any of the animals by 16 weeks. The dura mater remained intact in all subjects. Gross, histologic, and radiographic assays confirmed these findings. Although several studies have implanted human osteoprogenitor cells in vivo in various animal models, few have documented the appropriate controls or conditions necessary to support the potential to translate benchtop findings into clinical applications. We propose in this study that the nude mouse critical-sized calvarial defect model will be valuable with increasing investigations with human osteoprogenitor cells.

    View details for Web of Science ID 000252619900032

    View details for PubMedID 18216688

  • Noggin suppression enhances in vitro osteogenesis and accelerates in vivo bone formation JOURNAL OF BIOLOGICAL CHEMISTRY Wan, D. C., Pomerantz, J. H., Brunet, L. J., Kim, J., Chou, Y., Wu, B. M., Harland, R., Blau, H. M., Longaker, M. T. 2007; 282 (36): 26450-26459

    Abstract

    Several investigations have demonstrated a precise balance to exist between bone morphogenetic protein (BMP) agonists and antagonists, dictating BMP signaling and osteogenesis. We report a novel approach to manipulate BMP activity through a down-regulation of the potent BMP antagonist Noggin, and examined the effects on the bone forming capacity of osteoblasts. Reduction of noggin enhanced BMP signaling and in vitro osteoblast bone formation, as demonstrated by both gene expression profiles and histological staining. The effects of noggin suppression on in vivo bone formation were also investigated using critical-sized calvarial defects in mice repaired with noggin-suppressed osteoblasts. Radiographic and histological analyses revealed significantly more bone regeneration at 2 and 4 weeks post-injury. These findings strongly support the concept of enhanced osteogenesis through a down-regulation in Noggin and suggest a novel approach to clinically accelerate bone formation, potentially allowing for earlier mobilization of patients following skeletal injury or surgical resection.

    View details for DOI 10.1074/jbc.M703282200

    View details for Web of Science ID 000249239600050

    View details for PubMedID 17609215

  • Refining retinoic acid stimulation for osteogenic differentiation of murine adipose-derived adult stromal cells TISSUE ENGINEERING Wan, D. C., Siedhoff, M. T., Kwan, M. D., Nacamuli, R. P., Wu, B. M., Longaker, M. T. 2007; 13 (7): 1623-1631

    Abstract

    Murine adipose-derived adult stromal cells (ADAS) seeded onto appropriate scaffolds and pre-incubated with retinoic acid have been shown to generate in vivo bone rapidly. Prompt resorption ensues, however, as a result of osteoclastogenesis, likely secondary to retinoic acid carryover. In this study, we determined the effects of abbreviated retinoic acid exposure on ADAS osteogenic differentiation. Histological staining and gene expression analysis revealed that longer retinoic acid exposure resulted in better in vitro bone differentiation. However, significant osteogenesis was observed in ADAS after just 15 days of retinoic acid supplementation, suggesting that continual culture with retinoic acid is unnecessary for initiation of the osteogenic program. This was confirmed using ADAS pre-incubated in monolayer with an abbreviated 15 days of retinoic acid exposure before implantation into critical-sized calvarial defects. Similar rates of regeneration were observed between ADAS exposed to for 15 days or for a full 25-day course of retinoic acid before defect repair. Furthermore, by limiting retinoic acid exposure to ADAS in monolayer without scaffold, accelerated bone formation was observed without concomitant osteoclastic resorption. These data suggest that skeletal regeneration may be improved by modulating retinoic acid exposure before implantation, markedly accelerating the repair of bone defects using ADAS.

    View details for DOI 10.1089/ten.2006.0283

    View details for Web of Science ID 000248035500022

    View details for PubMedID 17518707

  • Re: Differential effects of FGFR2 mutation in ophthalniologic findings in Apert syndrome. Discussion JOURNAL OF CRANIOFACIAL SURGERY Kwan, M. D., Wan, D. C., Lorenz, H. P., Longaker, M. T. 2007; 18 (2): 459-460

    View details for Web of Science ID 000245424400039

    View details for PubMedID 17414305

  • Osteogenic differentiation of mouse adipose-derived stromal cells requires retinoic acid and bone morphogenetic protein type IB signaling CRANIOFACIAL SURGERY: PROCEEDINGS OF THE TWELFTH INTERNATIONAL CONGRESS OF THE INTERNATIONAL SOCIETY OF CRANIOFACIAL SURGERY Wan, D. C., Shi, Y. Y., Nacamull, R. P., Quarto, N., Kwan, M. D., Gupta, D. M., Slater, B. J., LYONS, K. M., Longaker, M. T. 2007: 45-47
  • Bilateral macrostomia as an isolated pathology CLEFT PALATE-CRANIOFACIAL JOURNAL Gleizal, A., Wan, D. C., Picard, A., Lavis, J., Vazquez, M., Beziat, J. 2007; 44 (1): 58-61

    Abstract

    Congenital macrostomia is a lateral orofacial cleft between the maxillary and mandibular components of the first branchial arch. Bilateral macrostomia is a poorly characterized malformation, with only 14 cases reported in the literature. The purpose of this study was to compare our experience with the world literature.A retrospective analysis of 20 cases of bilateral congenital macrostomia was conducted; 6 cases were drawn from 2 maxillofacial surgery units and 14 cases from the world literature. Cases of bilateral congenital macrostomia were compared with cases of unilateral forms using a review of the literature post-1954. Among the six cases identified from the two maxillofacial surgery units, three were treated with linear sutures and three with Z-plasty. Subsequent aesthetic and functional results were analyzed.Compared to unilateral forms, bilateral macrostomia is more often isolated without ear or skin deformities. Moreover, there are a greater proportion of larger defects among cases with bilateral macrostomia when compared to unilateral macrostomia. Alimentation, phonation, and mouth opening were always normal. The two sides were always symmetric. Only one case presented with the complication of skin contractions during lip movement.The etiopathogenesis of bilateral macrostomia is unclear. Although over 50% of the reported cases of bilateral macrostomia are isolated, this condition presents a therapeutic challenge. In the case of bilateral forms, the surgeon must define the commissure position without a normal side. Repair thus requires extraoral landmarks and normal measurements.

    View details for Web of Science ID 000243465200008

    View details for PubMedID 17214527

  • Applications of an Athymic nude mouse model of nonhealing critical-sized calvarial defects CRANIOFACIAL SURGERY: PROCEEDINGS OF THE TWELFTH INTERNATIONAL CONGRESS OF THE INTERNATIONAL SOCIETY OF CRANIOFACIAL SURGERY Gupta, D. M., Kwan, M. D., Slater, B. J., Wan, D. C., Longaker, M. T. 2007: 53-55
  • Gene expression differences between the dura mater of fusing and patent sutures in the mouse model CRANIOFACIAL SURGERY: PROCEEDINGS OF THE TWELFTH INTERNATIONAL CONGRESS OF THE INTERNATIONAL SOCIETY OF CRANIOFACIAL SURGERY Kwan, M. D., Wan, D. C., Wang, Z., Gupta, D. M., Slater, B. J., Beck, D., Longaker, M. T. 2007: 21-24
  • Noggin suppression enhances in vivo bone formation CRANIOFACIAL SURGERY: PROCEEDINGS OF THE TWELFTH INTERNATIONAL CONGRESS OF THE INTERNATIONAL SOCIETY OF CRANIOFACIAL SURGERY Wan, D. C., Pomerantz, J. H., Brunet, L. J., Kim, J., Chou, Y., Kwan, M. D., Slater, B. J., Gupta, D. M., Wu, B. M., Harland, R. M., Blau, H. M., Longaker, M. T. 2007: 49-52
  • Differential expression of sclerostin between juvenile and adult mice CRANIOFACIAL SURGERY: PROCEEDINGS OF THE TWELFTH INTERNATIONAL CONGRESS OF THE INTERNATIONAL SOCIETY OF CRANIOFACIAL SURGERY Kwan, M. D., Gupta, D. M., Slater, B. J., Wan, D. C., Quarto, N., Longaker, M. T. 2007: 17-19
  • Geometric morphometric analysis identifies craniofacial deformity in the noggin mutant CRANIOFACIAL SURGERY: PROCEEDINGS OF THE TWELFTH INTERNATIONAL CONGRESS OF THE INTERNATIONAL SOCIETY OF CRANIOFACIAL SURGERY Gupta, D. M., Young, N. M., Wan, D. C., Kwan, M. D., Slater, B. J., Brunet, L. J., Harland, R. M., Helms, J. A., Longaker, M. T. 2007: 13-15
  • Microarray analysis of differential gene expression between juvenile and adult calvarial defects CRANIOFACIAL SURGERY: PROCEEDINGS OF THE TWELFTH INTERNATIONAL CONGRESS OF THE INTERNATIONAL SOCIETY OF CRANIOFACIAL SURGERY Wan, D. C., Kwan, M. D., Wang, Z., Slater, B. J., Gupta, D. M., Longaker, M. T. 2007: 61-63
  • Refining retinoic acid stimulation of murine adipose-derived stromal cells accelerates in vivo bone formation CRANIOFACIAL SURGERY: PROCEEDINGS OF THE TWELFTH INTERNATIONAL CONGRESS OF THE INTERNATIONAL SOCIETY OF CRANIOFACIAL SURGERY Wan, D. C., Siedhoff, M. T., Kwan, M. D., Nacamuli, R. P., Slater, B. J., Gupta, D. M., Wu, B. M., Longaker, M. T. 2007: 57-59
  • Rotation of cranial sutures to determine the role of regional dura mater on cranial suture fate CRANIOFACIAL SURGERY: PROCEEDINGS OF THE TWELFTH INTERNATIONAL CONGRESS OF THE INTERNATIONAL SOCIETY OF CRANIOFACIAL SURGERY Slater, B. J., Kwan, M. D., Gupta, D. M., Amasha, R. R., Wan, D. C., Longaker, M. T. 2007: 65-67
  • Differential gene expression between juvenile and adult dura mater: A window into what genes play a role in the regeneration of membranous bone PLASTIC AND RECONSTRUCTIVE SURGERY Wan, D. C., Aalami, O. O., Wang, Z., Nacamuli, R. P., Lorget, F., Derynck, R., Longaker, M. T. 2006; 118 (4): 851-861

    Abstract

    Although reossification of large calvarial defects is possible in children, adults lack this tissue engineering capacity. In this study, the authors compared the differences in gene expression between juvenile and adult dura mater using a mouse cDNA microarray with 42,000 unique elements.Non-suture-associated parietal bone was harvested from 6-day-old and 60-day-old mice. The dura mater was carefully dissected from the calvarial disk and snap-frozen. RNA was extracted from pooled dura mater for microarray analysis. The 25 most differentially expressed genes were listed, as were selected bone-related genes. In addition, quantitative real-time reverse-transcriptase polymerase chain reaction confirmation of selected genes-BMP-2, BMP-4, and BMP-7; and osteopontin (OP), osteocalcin (OC), and FGFR-1-was performed.Juvenile dura mater expressed significantly greater amounts of BMP-2 and OP. Minimal difference in OC expression was observed between juvenile and adult dura mater. Extracellular matrix proteins (Col3a1, 5a1, 6a1, and fibronectin 1), osteoblast differentiation markers (Runx2/Cbfa1, Itm2a, and FGFR-1), and the growth factor Ptn were among other genes with greater expression in juvenile dura mater. Markers of osteoclasts (Acp5, MMP9, Ctsk) and the multiple candidate gene Ntrk2 were also expressed at higher levels in the juvenile dura mater.These findings suggest a more differentiated osteoprogenitor population to exist along with a greater presence of osteoclasts in the juvenile dura mater relative to adults. In addition to establishing a baseline difference in gene expression between juvenile and adult dura mater, new genes potentially critical to the regenerative potential of juvenile calvaria were identified.

    View details for DOI 10.1097/01.prs.0000232366.23897.2b

    View details for Web of Science ID 000240700100004

    View details for PubMedID 16980845

  • Osteogenic differentiation of mouse adipose-derived adult stromal cells requires retinoic acid and bone morphogenetic protein receptor type IB signaling PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Wan, D. C., Shi, Y., Nacamuli, R. P., Quarto, N., Lyons, K. M., Longaker, M. T. 2006; 103 (33): 12335-12340

    Abstract

    Although the multilineage potential of human adipose-derived adult stromal cells (ADAS) has been well described, few published studies have investigated the biological and molecular mechanisms underlying osteogenic differentiation of mouse ADAS. We report here that significant osteogenesis, as determined by gene expression and histological analysis, is induced only when mouse ADAS are cultured in the presence of retinoic acid with or without recombinant human bone morphogenetic protein (BMP)-2 supplementation. Furthermore, a dynamic expression profile for the BMP receptor (BMPR) isoform IB was observed, with dramatic up-regulation during osteogenesis. Western blot analysis revealed that retinoic acid enhanced levels of BMPR-IB protein during the first 7 days of osteogenic differentiation and that RNAi-mediated suppression of BMPR-IB dramatically impaired the ability of ADAS to form bone in vitro. In contrast, absence of BMPR-IA did not significantly diminish ADAS osteogenesis. Our data therefore demonstrate that the osteogenic commitment of multipotent mouse ADAS requires retinoic acid, which enhances expression of the critical BMPR-IB isoform.

    View details for DOI 10.1073/pnas.0604849103

    View details for Web of Science ID 000239867500026

    View details for PubMedID 16894153

  • Craniofacial bone tissue engineering. Dental clinics of North America Wan, D. C., Nacamuli, R. P., Longaker, M. T. 2006; 50 (2): 175-?

    Abstract

    Repair and reconstruction of the craniofacial skeleton represents a significant biomedical burden, with thousands of procedures per-formed annually secondary to injuries and congenital malformations. Given the multitude of current approaches, the need for more effective strategies to repair these bone deficits is apparent. This article explores two major modalities for craniofacial bone tissue engineering: distraction osteogenesis and cellular based therapies. Current understanding of the guiding principles for each of these modalities is elaborated on along with the knowledge gained from clinical and investigative studies. By laying this foundation, future directions for craniofacial distraction and cell-based bone engineering have emerged with great promise for the advancement of clinical practice.

    View details for PubMedID 16530056

  • The ISCFS: A body for clinical, educational, and research innovation JOURNAL OF CRANIOFACIAL SURGERY Longaker, M. T., Wan, D. C. 2006; 17 (2): 215-216

    View details for Web of Science ID 000236747300002

    View details for PubMedID 16633164

  • Murine models of mandibular distraction osteogenesis: Towards defining the mechanical environment and the role of angiogenesis PROCEEDINGS OF THE 5TH INTERNATIONAL CONGRESS OF MAXILLOFACIAL AND CRANIOFACIAL DISTRACTION Kwan, M. D., Wan, D. C., Loboa, E. G., Fang, T. D., Longaker, M. T. 2006: 1-4
  • Mechanisms of osteogenic differentiation of mouse adipose-derived mesenchymal cells CRANIOFACIAL SURGERY Shi, Y. Y., Nacamuli, R. P., Salim, A., Quarto, N., LYONS, K. M., Wan, D. C., Cowan, C. M., Helms, J. A., Longaker, M. T. 2005: 63-65
  • Embryologic tissue derivation affects post-natal calvarial healing CRANIOFACIAL SURGERY Wan, D. C., Shi, Y. Y., Siedhoff, M. T., Nacamuli, R. P., Longaker, M. T. 2005: 11-13
  • Distinct biologic properties of FACS-sorted murine adipose-derived mesenchymal cells CRANIOFACIAL SURGERY Siedhoff, M. T., Nacamuli, R. P., Wan, D. C., Shi, Y. Y., Bhattacharya, D., Weissman, I. L., Longaker, M. T. 2005: 55-57
  • Noggin suppression enhances osteogenesis of murine osteoblasts CRANIOFACIAL SURGERY Wan, D. C., Pomerants, J. H., Nacamuli, R. P., Kim, J. B., Blau, H. M., Longaker, M. T. 2005: 3-5
  • Determining the most effective time course of retinoic acid priming for murine adipose-derived mesenchymal cell osteogenesis CRANIOFACIAL SURGERY Siedhoff, M. T., Nacamuli, R. P., Wan, D. C., Shi, Y. Y., Longaker, M. T. 2005: 51-53
  • Identifying optimal retinoic acid dose for adipose-derived mesenchymal cell osteogenesis CRANIOFACIAL SURGERY Wan, D. C., Shi, Y. Y., Siedhoff, M. T., Nacamuli, R. P., Longaker, M. T. 2005: 59-61
  • Quantitative transcriptional analysis of fusing and nonfusing cranial suture complexes in mice CRANIOFACIAL SURGERY Nacamuli, R. P., Song, H. M., Fang, T. D., Fong, K. D., Mathy, J. A., Shi, Y. Y., Salim, A., Wan, D. C., Longaker, M. T. 2005: 277-279
  • Cranial suture biology CURRENT TOPICS IN DEVELOPMENTAL BIOLOGY, VOL 66 Lenton, K. A., Nacamuli, R. P., Wan, D. C., Helms, J. A., Longaker, M. T. 2005; 66: 287-?

    View details for Web of Science ID 000228212000009

    View details for PubMedID 15797457

  • New developments in pediatric plastic surgery research CLINICS IN PLASTIC SURGERY Nacamuli, R. P., Wan, D. C., Lenton, K. A., Longaker, M. T. 2005; 32 (1): 123-?

    Abstract

    Pediatric plastic surgery research is a rapidly expanding field. Unique in many ways, researchers in this field stand at the union of multiple scientific specialties, including biomedical engineering, tissue engineering, polymer science, molecular biology, developmental biology, and genetics. The goal of this scientific effort is to translate research advances into improved treatments for children with congenital and acquired defects. Although the last decade has seen a dramatic acceleration in research related to pediatric plastic surgery, the next 10 years will no doubt lead to novel treatment strategies with improved clinical outcomes.

    View details for DOI 10.1016/j.cps.2004.10.003

    View details for Web of Science ID 000226935600013

    View details for PubMedID 15636770

Conference Proceedings


  • Craniofacial Microsomia Soft-Tissue Reconstruction Comparison: Inframammary Extended Circumflex Scapular Flap versus Serial Fat Grafting Tanna, N., Wan, D. C., Kawamoto, H. K., Bradley, J. P. LIPPINCOTT WILLIAMS & WILKINS. 2011: 802-811

    Abstract

    The authors investigated the use of serial autologous fat grafting to restore soft-tissue contour in craniofacial microsomia patients.Patients with moderate to severe craniofacial microsomia were divided into two groups. Microvascular free flap patients had reconstruction with inframammary extended circumflex scapular flaps at skeletal maturity (n = 10). Alternatively, patients had fat grafting during multiple staged operations for mandible and ear reconstruction (n = 21). Sex, age, severity of deformity [determined by OMENS (orbital deformity, mandibular hypoplasia, ear deformity, nerve involvement, and soft-tissue deficiency) classification], number of procedures, operative times, and augmentation volumes were recorded. A digital three-dimensional photogrammetry system was used to determine "final fat take" and symmetry (affected side versus unaffected side). Physician and patient satisfaction were elicited.Microvascular free flap and fat grafting groups had similar OMENS scores, 2.4 and 2.3, and similar mean prereconstruction symmetry scores, 74 percent and 75 percent, respectively. Although the mean number of procedures was less for the microvascular free flap group versus the fat grafting group (2.2 versus 4.3), the combined surgical time was greater for the microvascular free flap group. The complication rate for the microvascular free flap group was 12 percent and that for the fat grafting group was 5 percent. The mean microvascular free flap volume implanted was 131 cc, with a final measured volume of 106 cc. Mean fat grafting volume injected per case was 33 cc, with total fat injections of 146 cc and a final measured volume of 121 cc. There was a mean fat loss of 25 cc and 83 percent fat take. Symmetry score was 121 percent for the microvascular free flap group and 99 percent for the fat grafting group. No statistically significant difference in patient or physician satisfaction was noted.Serial fat grafting provided a useful alternative to microvascular free tissue transfer after skeletal reconstruction.

    View details for DOI 10.1097/PRS.0b013e3181fed6e4

    View details for Web of Science ID 000286928100039

    View details for PubMedID 21285784

  • Highlights of the proceedings from the 12th International Congress of the International Society of Craniofacial Surgery: ISCFS 2007. Wan, D. C., Kwan, M. D., Bradley, J. P. 2008: 551-554

    View details for DOI 10.1097/SCS.0b013e3181642654

    View details for PubMedID 18362757

  • Geometric morphometric analysis of craniofacial deformity in the noggin mutant Gupta, D. M., Young, N. M., Wan, D. C., Brunet, L. J., Harland, R. M., Helms, J. A., Longaker, M. T. ELSEVIER SCIENCE INC. 2007: S60-S60
  • Differential expression of sclerostin in the calvaria of young and adult mice Kwan, M. D., Slater, B., Deepak, G., Wan, D., Longaker, M. T. ELSEVIER SCIENCE INC. 2007: S59-S59
  • BMP antagonism via noggin in adult dura mater Kwan, M. D., Wan, D., Longaker, M. ELSEVIER SCIENCE INC. 2006: S55-S55
  • Fluorescence-activated cell sorting with CD105 identifies osteoprogenitors within mouse and human-derived AMCs Wan, D. C., Kwan, M., Nacamuli, R., Tataria, M., Longaker, M. ELSEVIER SCIENCE INC. 2006: S42-S42
  • Noggin suppression enhances osteogenesis of murine osteoblasts Wan, D. C., Pomerantz, J., Nacamuli, R., Siedhoff, M., Blau, H., Longaker, M. T. ELSEVIER SCIENCE INC. 2005: S62-S62

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