Bio

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Journal Articles


  • Optimization of an Injectable Tendon Hydrogel: The Effects of Platelet-Rich Plasma and Adipose-Derived Stem Cells on Tendon Healing In Vivo TISSUE ENGINEERING PART A Chiou, G. J., Crowe, C., McGoldrick, R., Hui, K., Pham, H., Chang, J. 2015; 21 (9-10): 1579-1586

    Abstract

    Acute and chronic tendon injuries would benefit from stronger and more expeditious healing. We hypothesize that supplementation of a biocompatible tendon hydrogel with platelet-rich plasma (PRP) and adipose-derived stem cells (ASCs) would augment the tendon healing process.Using 55 Wistar rats, a full-thickness defect was created within the midsubstance of each Achilles tendon with the addition of one of five experimental conditions: (i) saline control (50-?L), (ii) tendon hydrogel (50-?L), (iii) tendon hydrogel (45-?L)+PRP (5-?L), (iv) tendon hydrogel (45-?L)+210(6)-ASCs/mL in phosphate buffered saline (5-?L), and (v) tendon hydrogel (45-?L)+210(6)-ASCs/mL in PRP (5-?L). Hydrogel was developed from decellularized, human cadaveric tendons. Fresh rat PRP was obtained per Amable et al.'s technique, and green fluorescent protein/luciferase-positive rat ASCs were utilized. Rats were sacrificed at weeks 1, 2, 4, and 8 after injury. Real-time in vivo bioluminescence imaging of groups with ASCs was performed. Upon sacrifice, Achilles tendons underwent biomechanical and histological evaluation. Comparisons across groups were analyzed using the two-sample Z-test for proportions and the Student's t-test for independent samples. Significance was set at p<0.05.(i) Bioluminescence imaging demonstrated that total photon flux was significantly increased for hydrogel+PRP+ASCs, versus hydrogel+ASCs for each postoperative day imaged (p<0.03). (ii) Mean ultimate failure load (UFL) was increased for hydrogel augmented with PRP and/or ASCs versus hydrogel alone at week 2 (p<0.03). By week 4, hydrogel alone reached a similar mean UFL to hydrogel augmented with PRP and/or ASCs (p>0.3). However, at week 8, hydrogel with PRP and ASCs demonstrated increased strength over other groups (p<0.05), except for hydrogel with PRP (p=0.25). (iii) Upon histological analysis, Hematoxylin and Eosin staining showed increased extracellular matrix formation in groups containing PRP and increased cellularity in groups containing ASCs. Groups containing both PRP and ASCs demonstrated both of these characteristics.PRP and ASCs are easily accessible bioactive products that have potentiating effects on tendon hydrogel. Augmentation with these two factors encourages earlier mechanical strength and functional restoration. Thus, biochemically, tendon hydrogel augmented with PRP and/or ASCs, serves as a promising therapeutic modality for augmenting the tendon healing process after injury.

    View details for DOI 10.1089/ten.tea.2014.0490

    View details for Web of Science ID 000353952300010

    View details for PubMedID 25625433

  • Tendon regeneration with a novel tendon hydrogel: in vitro effects of platelet-rich plasma on rat adipose-derived stem cells. Plastic and reconstructive surgery Crowe, C. S., Chiou, G., McGoldrick, R., Hui, K., Pham, H., Chang, J. 2015; 135 (6): 981e-9e

    Abstract

    Tendon hydrogel is a promising new injectable substance that has been shown to improve repair strength after tendon injury. This study assesses the capacity of platelet-rich plasma to stimulate proliferation and migration of rat adipose-derived stem cells in tendon hydrogel in vitro.To assess proliferation, adipose-derived stem cells were exposed to plasma, plasma supplemented with growth factors, or platelet-rich plasma in culture medium and tendon hydrogel. To assess migration, adipose-derived stem cells were plated onto tendon hydrogel -coated wells and covered with medium containing plasma, plasma supplemented with growth factors, platelet-rich plasma, or bovine serum albumin. Migration from cell-seeded to cell-free zones was assessed at 12-hour intervals.Platelet-rich plasma augmented proliferation to a greater extent compared with plasma and plasma supplemented with growth factors (10%: optical density, 1.18 versus 0.75 versus 0.98, respectively). Platelet-rich plasma was superior to plasma in tendon hydrogel (10%: optical density, 1.19 versus 0.85) but did not augment proliferation to the extent that plasma supplemented with growth factors did (10%: optical density, 1.19 versus 1.56). Platelet-rich plasma enhanced the migration of adipose-derived stem cells compared with serum-free medium (bovine serum albumin) (36 hours: platelet-rich plasma, 1.88; plasma, 1.51; plasma plus growth factor, 1.80; bovine serum albumin, 1.43).Tendon healing is mediated by migration of cells to the injured area and cellular proliferation at that site. Tendon hydrogel supplemented with platelet-rich plasma stimulates these processes. Future studies will evaluate this combination's ability to stimulate healing in chronic tendon injuries in vivo.

    View details for DOI 10.1097/PRS.0000000000001268

    View details for PubMedID 26017614

  • Tissue engineering in flexor tendon surgery: current state and future advances JOURNAL OF HAND SURGERY-EUROPEAN VOLUME Galvez, M. G., Crowe, C., Farnebo, S., Chang, J. 2014; 39 (1): 71-78
  • In Vitro Characteristics of Porcine Tendon Hydrogel for Tendon Regeneration. Annals of plastic surgery Crowe, C. S., Chiou, G., McGoldrick, R., Hui, K., Pham, H., Hollenbeck, E., Chang, J. 2014

    Abstract

    Previous work has characterized the development of a human tendon hydrogel capable of improving mechanical strength after tendon injury. Animal tendon hydrogel has not yet been described, but would prove beneficial due to the cost and ethical concerns associated with the use of human cadaveric tendon. This study details the manufacture and assesses the biocompatibility of porcine tendon hydrogel seeded with human adipoderived stem cells (ASCs).Porcine tendon was dissected from surrounding connective and muscle tissue and decellularized via 0.2% sodium dodecyl sulfate and 0.2% sodium dodecyl sulfate/ethylenediaminetetraacetic acid wash solutions before lyophilization. Tendon was milled and reconstituted by previously described methods. Decellularization was confirmed by hematoxylin-eosin staining, SYTO Green 11 nucleic acid dye, and DNeasy assay. The protein composition of milled tendon matrix before and after digestion was identified by mass spectrometry. Rheological properties were determined using an ARG2 rheometer. Biocompatibility was assessed by live/dead assay. The proliferation of human ASCs seeded in porcine and human hydrogel was measured by MTS assay. All experimental conditions were performed in triplicate.Decellularization of porcine tendon was successful. Mass spectrometry showed that collagen composes one third of milled porcine tendon before and after pepsin digestion. Rheology demonstrated that porcine hydrogel maintains a fluid consistency over a range of temperatures, unlike human hydrogel, which tends to solidify. Live/dead staining revealed that human ASCs survive in hydrogel 7 days after seeding and retain spindle-like morphology. MTS assay at day 3 and day 5 showed that human ASC proliferation was marginally greater in human hydrogel.After reconstitution and digestion, porcine hydrogel was capable of supporting growth of human ASCs. The minimal difference in proliferative capacity suggests that porcine tendon hydrogel may be an effective and viable alternative to human hydrogel for the enhancement of tendon healing.

    View details for DOI 10.1097/SAP.0000000000000361

    View details for PubMedID 25305229

  • Comparative effectiveness of bariatric surgery for cardiac risk factor improvement JOURNAL OF THE AMERICAN COLLEGE OF SURGEONS Morton, J. M., Crowe, C., Leva, N., Rivas, H. 2013; 217 (3): S15-S16
  • "Click" and Olefin Metathesis Chemistry in Water at Room Temperature Enabled by Biodegradable Micelles. Journal of chemical education Lipshutz, B. H., Bo?kovi?, Z., Crowe, C. S., Davis, V. K., Whittemore, H. C., Vosburg, D. A., Wenzel, A. G. 2013; 90 (11)

    Abstract

    The two laboratory reactions focus on teaching several concepts associated with green chemistry. Each uses a commercial, nontoxic, and biodegradable surfactant, TPGS-750-M, to promote organic reactions within the lipophilic cores of nanoscale micelles in water. These experiments are based on work by K. Barry Sharpless (an azide-alkyne "click" reaction) and Robert Grubbs (an olefin cross-metathesis reaction); both are suitable for an undergraduate organic laboratory. The copper-catalyzed azide-alkyne [3+2] cycloaddition of benzyl azide and 4-tolylacetylene is very rapid: the triazole product is readily isolated by filtration and is characterized by thin-layer chromatography and melting point analysis. The ruthenium-catalyzed olefin cross-metathesis reaction of benzyl acrylate with 1-hexene is readily monitored by thin-layer chromatography and gas chromatography. The metathesis experiment comparatively evaluates the efficacy of a TPGS-750-M/water medium relative to a traditional reaction performed in dichloromethane (a common solvent used for olefin metathesis).

    View details for DOI 10.1021/ed300893u

    View details for PubMedID 24324282

  • CuH-Catalyzed Enantioselective 1,2-Reductions of alpha,beta-Unsaturated Ketones JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Moser, R., Boskovic, Z. V., Crowe, C. S., Lipshutz, B. H. 2010; 132 (23): 7852-?

    Abstract

    The first study on a general technology for arriving at valued nonracemic allylic alcohols using asymmetric ligand-accelerated catalysis by copper hydride is described.

    View details for DOI 10.1021/ja102689e

    View details for Web of Science ID 000278717700015

    View details for PubMedID 20481528

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