Bio

Clinical Focus


  • Abdominal Transplant
  • Immunology
  • Wound Healing
  • General Surgery

Academic Appointments


Honors & Awards


  • Henry J. Kaiser Family Foundation Award for Excellence in Clinical Teaching, Stanford Medical School (2019)
  • Resident Teaching Award, Stanford Medical School (2018)
  • Holman Research Day, Best Basic/Translational Science Presentation, Department of Surgery, Stanford University (2017)
  • Surgical Honors Society, Loyola University Chicago, Stritch School of Medicine (2013)
  • Presidential Award Finalist, 2nd Place, Society for Leukocyte Biology (2012)
  • Alpha Sigma Nu, Loyola University Chicago (2011)
  • Julius Jacobson Award, International Union of Angiology (2008)

Professional Education


  • Residency:Stanford University General Surgery Residency (2019) CA
  • Medical Education:Loyola University Stritch School of Medicine (2014) IL
  • MD PhD, Loyola University Chicago, Stritch School of Medicine (2014)
  • BS, Pepperdine University, Physiological Psychology (2006)

Research & Scholarship

Projects


  • Circulating Cell Free DNA as an Early Diagnostic Marker of Acute Rejection following Liver and Kidney Transplant

    Location

    Stanford, CA

    Collaborators

    • Amy Gallo, Assistant Professor, Stanford Universuty
  • Utilization of TEG to decreased Peri-operative Transfusion Requirements in Transplant

    Location

    Stanford, CA

Publications

All Publications


  • Ureterostomy may be a superior alternative to ileal conduits in pediatric kidney transplantation Brubaker, A. L., Vuong, P., Stoltz, D. J., Grimm, P. C., Concepcion, W., Gallo, A. WILEY. 2019
  • Superior Hypertension Management in Pediatric Kidney Transplant Patients After Native Nephrectomy TRANSPLANTATION Brubaker, A. L., Stoltz, D. J., Chaudhuri, A., Maestretti, L., Grimm, P. C., Concepcion, W., Gallo, A. E. 2018; 102 (7): 1172?78
  • Superior Hypertension Management in Pediatric Kidney Transplant Patients After Native Nephrectomy. Transplantation Brubaker, A. L., Stoltz, D. J., Chaudhuri, A., Maestretti, L., Grimm, P. C., Concepcion, W., Gallo, A. E. 2018; 102 (7): 1172?78

    Abstract

    BACKGROUND: Native nephrectomy in pediatric kidney transplant recipients is performed for multiple indications. Posttransplant hypertension requiring medical management is common, and the effect of native nephrectomy on posttransplant hypertension is poorly studied. Our aim is to evaluate the impact of native nephrectomy on posttransplant hypertension.METHODS: One hundred thirty-six consecutive pediatric kidney transplant recipients from 2007 to 2012 were studied at a single institution and divided into 2 groups: no nephrectomy and native nephrectomy (unilateral and bilateral nephrectomy). Antihypertensive medication use was evaluated before nephrectomy/transplant, at discharge from transplant and at 1, 3, and 5 years posttransplant.RESULTS: In a bivariate analysis, nephrectomy was associated with a significant reduction in the percentage of patients requiring antihypertensive medication at the time of discharge (27.3%) and 1 year posttransplant (10.7%) as compared with patients without nephrectomy (71.7%, and 50%, respectively, P < 0.05). This trend toward reduction in antihypertensive medication in the nephrectomy group as compared with the no nephrectomy group persisted at 3 (18.6% versus 43.2%) and 5 years (19.7% versus 37.5%) posttransplant. Multivariable logistic regression demonstrated that patients without native nephrectomy had higher odds of requiring antihypertensive medication at the time of discharge (3.3) and 1 year (5.2) as compared with patients who underwent native nephrectomy (P = 0.036 and P = 0.013, respectively).CONCLUSIONS: Native nephrectomy reduces the odds of needing antihypertensive medication after transplant. The impact of native nephrectomy is crucial to the comprehensive management of pediatric transplant recipients where medication compliance is challenging and lifelong hypertension is known to negatively impact cardiovascular health.

    View details for PubMedID 29953422

  • Donor-derived Cell-free DNA Predicts Biopsy-proven Acute Cellular Rejection in Pediatric Kidney Transplant Recipients. Stoltz, D., Brubaker, A., Grskovic, M., Woodward, R., Gallo, A. WILEY-BLACKWELL. 2017: 18
  • Experimental Approaches to Tissue Injury and Repair in Advanced Age IMMUNOSENESCENCE: METHODS AND PROTOCOLS Brubaker, A. L., Carter, S. R., Kovacs, E. J., Shaw, A. C. 2015; 1343: 35?51

    Abstract

    Cutaneous wound healing is a complex physiological process. This process can be altered by multiple physiological and pathological factors. Multiple pathophysiological disturbances act to impair resolution of cutaneous wound injury, including obesity, diabetes, peripheral vascular disease, and advanced age. As our longevity increases without a concomitant increase in healthy living years, it is plausible to assume that problematic wound closure will continue to consume a large portion of our health care resources. Furthermore, advanced age is associated with numerous alterations in the innate and adaptive immune responses that complicate outcomes following cutaneous injury, trauma, or infection. Thus, models that examine the impact of advanced age on cutaneous wound repair will be of great benefit to the development of potential therapeutics that target age-related aberrancies in tissue repair. Herein, we detail two animal models of tissue injury, excisional wound injury and burn injury, that can be used to evaluate wound healing in the context of advanced age. We also describe modifications of these methods to examine wound infection following either excisional or burn injury. Lastly, we discuss methods of subsequent tissue analysis following injury. Models described below can be further adapted to genetically engineered murine strains to study the effects of aging and other co-morbidities on wound healing.

    View details for PubMedID 26420707

  • Episodic Binge Ethanol Exposure ImpairsMurine Macrophage Infiltration and DelaysWound Closure by Promoting Defects in Early Innate Immune Responses ALCOHOLISM-CLINICAL AND EXPERIMENTAL RESEARCH Curtis, B. J., Hlavin, S., Brubaker, A. L., Kovacs, E. J., Radek, K. A. 2014; 38 (5): 1347-1355

    Abstract

    Exacerbation of cutaneous wound infections and delayed wound closure are frequent complications seen in alcohol exposed subjects who sustain injuries. We previously reported that acute alcohol exposure alters the early dermal inflammatory phase of wound healing and also several parameters of the proliferative wound healing phase in wounds from ethanol (EtOH)-treated mice for several days or weeks after EtOH exposure. Hence, it is likely that the cumulative defects arising in the early phases of the wound healing process directly contribute to the increased complications observed in intoxicated patients at the time of injury.C57BL/6 mice were given intraperitoneal EtOH (2.2 g/kg body weight) or vehicle (saline) EtOH using our episodic binge EtOH exposure protocol (3 days EtOH, 4 days off, 3 days EtOH) to yield a blood alcohol concentration (BAC) of 300 mg/dl at the time of wounding. Mice were subjected to six 3 mm full-thickness dorsal wounds and immediately treated topically with 10 ?l of sterile saline (control) or diluted Staphylococcus aureus corresponding to 1 10(4) CFU/wound. Wounds were harvested at 24 hours post injury to evaluate wound area, neutrophil and macrophage accumulation, and the protein levels of cytokines, interleukin-6 (IL-6), IL-1?, and IL-10, and chemokines, macrophage inflammatory protein-2 (MIP-2) and MIP-1?, monocyte chemotactic protein-1 (MCP-1), and keratinocyte-derived chemokine (KC). The abundance and localization of cathelicidin-related antimicrobial peptide (CRAMP) and the kallikrein epidermal proteases (KLK5 and KLK7) were also determined.Compared to control mice, EtOH-treated mice exhibited delayed wound closure, decreased macrophage accumulation, and impaired production of MIP-1?. Furthermore, skin from EtOH-treated mice demonstrated a reduction in the abundance of epidermal CRAMP and KLK7.These findings suggest that EtOH exposure hinders several distinct components of the innate immune response, including phagocyte recruitment and chemokine/cytokine and AMP production. Together, these effects likely contribute to delayed wound closure and enhanced infection severity observed in intoxicated patients.

    View details for DOI 10.1111/acer.12369

    View details for Web of Science ID 000334657200020

    View details for PubMedID 24689549

    View details for PubMedCentralID PMC4001884

  • The Role of Aryl Hydrocarbon Receptor in Interleukin-23-Dependent Restoration of Interleukin-22 Following Ethanol Exposure and Burn Injury ANNALS OF SURGERY Rendon, J. L., Li, X., Brubaker, A. L., Kovacs, E. J., Gamelli, R. L., Choudhry, M. A. 2014; 259 (3): 582-590

    Abstract

    T-helper (Th)-17 lymphocytes play a crucial role in maintenance and regulation of gut immunity. Our laboratory has demonstrated that acute ethanol (EtOH) exposure before burn injury results in intestinal T cell suppression and enhanced bacterial translocation.To extend these studies, we examined the effects of EtOH exposure and burn injury on Th17 responses within intestinal lymphoid Peyer's patches (PP). We further investigated whether restitution of interleukin (IL)-23 enhances PP cell IL-17 and IL-22 after EtOH and burn injury.Male mice, approximately 25 g, were gavaged with EtOH (2.9 mg/kg) before receiving an approximately 12.5% total body surface area full thickness burn. One day postinjury, PP mixed cells were cultured in the presence of plate-bound anti-CD3/soluble anti-CD28 in the presence or absence of IL-23 for 48 hours. Supernatants were harvested for IL-17 and IL-22 levels.When combined with EtOH intoxication, burn injury significantly decreased IL-17 and IL-22, as compared with sham injury. IL-23 treatment successfully increased levels of IL-22 but not IL-17. This restoration was prevented when PP cells were treated with CH-223191, an aryl hydrocarbon receptor inhibitor. To further delineate the mechanism of differential IL-17 and IL-22 suppression, PP cells were treated with phorbol 12-myristate 13-acetate (PMA) and ionomycin, which signal via protein kinase C (PKC) and calcium flux. Treatment with PMA and ionomycin significantly prevented the decrease in IL-17 but not IL-22 after EtOH exposure and burn injury.These findings suggest that IL-23-mediated restoration of IL-22 is aryl hydrocarbon receptor dependent, whereas IL-17 requires activation of protein kinase C and intracellular calcium signaling.

    View details for DOI 10.1097/SLA.0b013e3182a626f2

    View details for Web of Science ID 000336248000042

    View details for PubMedID 23989051

    View details for PubMedCentralID PMC3925750

  • G-CSF ENHANCES RESOLUTION OF STAPHYLOCOCCUS AUREUS WOUND INFECTION IN AN AGE-DEPENDENT MANNER SHOCK Brubaker, A. L., Kovacs, E. J. 2013; 40 (4): 327-333

    Abstract

    This study tested the hypothesis that heightened bacterial colonization and delayed wound closure in aged mice could be attenuated by granulocyte colony-stimulating factor (G-CSF) treatment. Previously, we reported that aged mice had elevated bacterial levels, protracted wound closure, and reduced wound neutrophil accumulation after Staphylococcus aureus wound infection relative to young mice. In aseptic wound models, G-CSF treatment improved wound closure in aged mice to rates observed in young mice. Given these data, our objective was to determine if G-CSF could restore age-associated differences in wound bacterial burden and closure by increasing wound neutrophil recruitment. Young (3- to 4-month) and aged (18- to 20-month) BALB/c mice received three dorsal subcutaneous injections of G-CSF (250 ng/50 ?L per injection) or saline control (50 ?L per injection) 30 min after wound infection. Mice were killed at days 3 and 7 after wound infection, and bacterial colonization, wound size, wound leukocyte accumulation, and peripheral blood were evaluated. At days 3 and 7 after wound infection, bacterial colonization was significantly reduced in G-CSF-treated aged mice to levels observed in saline-treated young animals. Wound size was reduced in G-CSF-treated aged animals, with no effect on wound size in G-CSF-treated young mice. Local G-CSF treatment significantly enhanced neutrophil wound accumulation in aged mice, whereas there was no G-CSF-induced change in young mice. These data demonstrate that G-CSF enhances bacterial clearance and wound closure in an age-dependent manner. Moreover, G-CSF may be of therapeutic potential in the setting of postoperative wound infection or chronic nonhealing wounds in elderly patients.

    View details for DOI 10.1097/SHK.0b013e3182a43651

    View details for Web of Science ID 000330246300011

    View details for PubMedID 23856924

    View details for PubMedCentralID PMC3792575

  • Reduced Neutrophil Chemotaxis and Infiltration Contributes to Delayed Resolution of Cutaneous Wound Infection with Advanced Age JOURNAL OF IMMUNOLOGY Brubaker, A. L., Rendon, J. L., Ramirez, L., Choudhry, M. A., Kovacs, E. J. 2013; 190 (4): 1746-1757

    Abstract

    Advanced age is associated with alterations in innate and adaptive immune responses, which contribute to an increased risk of infection in elderly patients. Coupled with this immune dysfunction, elderly patients demonstrate impaired wound healing with elevated rates of wound dehiscence and chronic wounds. To evaluate how advanced age alters the host immune response to cutaneous wound infection, we developed a murine model of cutaneous Staphylococcus aureus wound infection in young (3-4 mo) and aged (18-20 mo) BALB/c mice. Aged mice exhibit increased bacterial colonization and delayed wound closure over time compared with young mice. These differences were not attributed to alterations in wound neutrophil or macrophage TLR2 or Fc?RIII expression, or age-related changes in phagocytic potential and bactericidal activity. To evaluate the role of chemotaxis in our model, we first examined in vivo chemotaxis in the absence of wound injury to KC, a neutrophil chemokine. In response to a s.c. injection of KC, aged mice recruited fewer neutrophils at increasing doses of KC compared with young mice. This paralleled our model of wound infection, where diminished neutrophil and macrophage recruitment was observed in aged mice relative to young mice despite equivalent levels of KC, MIP-2, and MCP-1 chemokine levels at the wound site. This reduced leukocyte accumulation was also associated with lower levels of ICAM-1 in wounds from aged mice at early time points. These age-mediated defects in early neutrophil recruitment may alter the dynamics of the inflammatory phase of wound healing, impacting macrophage recruitment, bacterial clearance, and wound closure.

    View details for DOI 10.4049/jimmunol.1201213

    View details for Web of Science ID 000314825400038

    View details for PubMedID 23319733

    View details for PubMedCentralID PMC3563860

  • The aging lung. Clinical interventions in aging Lowery, E. M., Brubaker, A. L., Kuhlmann, E., Kovacs, E. J. 2013; 8: 1489-1496

    Abstract

    There are many age-associated changes in the respiratory and pulmonary immune system. These changes include decreases in the volume of the thoracic cavity, reduced lung volumes, and alterations in the muscles that aid respiration. Muscle function on a cellular level in the aging population is less efficient. The elderly population has less pulmonary reserve, and cough strength is decreased in the elderly population due to anatomic changes and muscle atrophy. Clearance of particles from the lung through the mucociliary elevator is decreased and associated with ciliary dysfunction. Many complex changes in immunity with aging contribute to increased susceptibility to infections including a less robust immune response from both the innate and adaptive immune systems. Considering all of these age-related changes to the lungs, pulmonary disease has significant consequences for the aging population. Chronic lower respiratory tract disease is the third leading cause of death in people aged 65 years and older. With a large and growing aging population, it is critical to understand how the body changes with age and how this impacts the entire respiratory system. Understanding the aging process in the lung is necessary in order to provide optimal care to our aging population. This review focuses on the nonpathologic aging process in the lung, including structural changes, changes in muscle function, and pulmonary immunologic function, with special consideration of obstructive lung disease in the elderly.

    View details for DOI 10.2147/CIA.S51152

    View details for PubMedID 24235821

    View details for PubMedCentralID PMC3825547

  • Elevated mortality and prolonged intestinal cell death following combined radiation and burn in a mouse model Carter, S. R., Zahs, A., Palmer, J. L., Brubaker, A. L., Wang, L., Ramirez, L., Choudhry, M. A., Yong, S. L., Gamelli, R. L., Kovacs, E. J. ELSEVIER SCIENCE INC. 2012: S19
  • Dysregulation of neutrophil CXCR2 and pulmonary endothelial icam-1 promotes age-related pulmonary inflammation. Aging and disease Nomellini, V., Brubaker, A. L., Mahbub, S., Palmer, J. L., Gomez, C. R., Kovacs, E. J. 2012; 3 (3): 234-247

    Abstract

    We have previously demonstrated that aging is associated with prolonged pulmonary inflammation in a murine model of thermal injury. To further investigate these observations, we examined lung congestion, markers of neutrophil chemotaxis and adhesion, and lung endothelia responses in young and aged mice following burn injury. Analysis of lung tissue and bronchoalveolar lavage fluid 24 hours after injury revealed that more neutrophils accumulated in the lungs of aged mice (p<0.05), but did not migrate into the alveoli. We then sought to determine if accumulation of neutrophils in the lungs of aged mice was due to differences in the peripheral neutrophil pool or local changes within the lung. Following burn injury, aged mice developed a pronounced peripheral blood neutrophilia (p<0.05) in comparison to their younger counterparts. In aged animals, there was a reduced frequency and mean fluorescent intensity of neutrophil CXCR2 expression (p<0.05). Interestingly, in uninjured aged mice, peripheral blood neutrophils demonstrated elevated chemokinesis, or hyperchemokinesis, (p<0.05), but showed a minimal chemotatic response to KC. To determine if age impacts neutrophil adhesion molecules, we assessed CD62L and CD11b expression on peripheral blood neutrophils. No age-dependent difference in the frequency or mean fluorescent intensity of CD62L or CD11b was observed post-burn trauma. Examination of pulmonary vasculature adhesion molecules which interact with neutrophil selectins and integrins revealed that intracellular adhesion molecule-1 (ICAM-1) was elevated in aged mice at 24 hours after burn as compared to young mice (p<0.05). Overall, our data suggests that age-associated pulmonary congestion observed following burn injury may be due to differences in lung endothelial adhesion responses that are compounded by elevated numbers of hyperchemokinetic circulating neutrophils in aged mice.

    View details for PubMedID 22724082

    View details for PubMedCentralID PMC3375080

  • Increased bacterial colonization and delayed wound closure in aged mice is associated with altered leukocyte recruitment Brubaker, A., Rendon, J., Choudhry, M., Kovacs, E. AMER ASSOC IMMUNOLOGISTS. 2012
  • An improved cell isolation method for flow cytometric and functional analyses of cutaneous wound leukocytes JOURNAL OF IMMUNOLOGICAL METHODS Brubaker, A. L., Schneider, D. F., Palmer, J. L., Faunce, D. E., Kovacs, E. J. 2011; 373 (1-2): 161-166

    Abstract

    Isolation of leukocytes from full-thickness excisional wounds has proven to be a difficult process that results in poor cell yield and holds significant limitations for functional assays. Given the increased interest in the isolation, characterization and functional measurements of wound-derived cell populations, herein we describe a method for preparing wound cell suspensions with an improved yield that enables both phenotypic and functional assessments.

    View details for DOI 10.1016/j.jim.2011.08.013

    View details for Web of Science ID 000297395400017

    View details for PubMedID 21889511

    View details for PubMedCentralID PMC3195830

  • Age-related Dysregulation of Inflammation and Innate Immunity: Lessons Learned from Rodent Models. Aging and disease Brubaker, A. L., Palmer, J. L., Kovacs, E. J. 2011; 2 (5): 346-360

    Abstract

    In the elderly patient population, it has become increasingly evident that immune dysregulation is a contributing factor to age-related pathologies and their associated morbidity and mortality. In particular, elderly subjects are plagued by poor responses to infectious challenge and immunization and are at heightened risk for the development of autoimmune, neuroinflammatory and tumor-associated pathologies. Rodent models of aging and age-related disorders have been utilized to better describe how innate immune cell dysfunction contributes to these clinical scenarios. As the elderly population continues to increase in size, use of these aging rodent models to study immune dysregulation may translate into increased healthy living years for these individuals.

    View details for PubMedID 22396887

  • Neutrophils and natural killer T cells as negative regulators of wound healing. Expert review of dermatology Brubaker, A. L., Schneider, D. F., Kovacs, E. J. 2011; 6 (1): 5-8

    View details for PubMedID 21442028

  • Aging of the Innate Immune System: An Update. Current immunology reviews Mahbub, S., Brubaker, A. L., Kovacs, E. J. 2011; 7 (1): 104-115

    Abstract

    The relationship between advanced age and immunologic deficits is becoming an area of rapidly advancing research. Many of the clinical hurdles in the elderly population result from dysregulation of the immune system leading to the inability of the elderly to swiftly combat infection and to the increased incidence of chronic disease states and autoimmune conditions. Herein, we address the crucial alterations in the innate immune system that occur with advancing age. Specifically, we discuss how the effects of advanced age may lead to functional changes in the neutrophil, macrophage, dendritic cell, natural killer cell, and natural killer T cell populations in human and murine models that translate into aberrant innate immune responses. Furthermore, we elucidate how these changes may contribute to documented deficits in adaptive immunity as well as the pathological conditions and the increased morbidity and mortality seen in the elderly population.

    View details for PubMedID 21461315

  • Impact of aging on dermal wound healing Brubaker, A. L., Mahbub, S., Deburghgrave, C., Kovacs, E. J. FEDERATION AMER SOC EXP BIOL. 2010
  • Neutralization of Unfractionated Heparin and Low Molecular Weight Heparin by Novel Salicylamide Derivatives Jeske, W., Brubaker, A., Liu, D., Young, T., Hoppensteadt, D., Iqbal, O., Fareed, J., Walenga, J., Bakhos, M. FEDERATION AMER SOC EXP BIOL. 2008
  • Differentiating low-molecular-weight heparins based on chemical, biological, and pharmacologic properties: Implications for the development of generic versions of low-molecular-weight heparins SEMINARS IN THROMBOSIS AND HEMOSTASIS Jeske, W. P., Walenga, J. M., Hoppensteadt, D. A., Vandenberg, C., Brubaker, A., Adiguzel, C., Bakhos, M., Fareed, J. 2008; 34 (1): 74-85

    Abstract

    Low-molecular-weight heparins (LMWHs) are polypharmacologic drugs used to treat thrombotic and cardiovascular disorders. These drugs are manufactured using different chemical and enzymatic methods, resulting in products with distinct chemical and pharmacologic profiles. Generic LMWHs have been introduced in Asia and South America, and several generic suppliers are seeking regulatory approval in the United States and the European Union. For simple small-molecule drugs, generic drugs have the same chemical structure, potency, and bioavailability as the innovator drug. Applying this definition to complex biological products such as the LMWHs has proved difficult. One major issue is defining appropriate criteria to demonstrate bioequivalence; pharmacopoeial specifications alone appear to be inadequate. Whereas available generic versions of LMWHs exhibit similar molecular and pharmacopoeial profiles, marked differences in their biological and pharmacologic behavior have been noted. Preliminary studies have demonstrated differences in terms of anti-Xa activity and tissue factor pathway inhibitor release after subcutaneous administration, as well as antiplatelet and profibrinolytic effects. The current data emphasize the need to consider multiple functional parameters when defining bioequivalence of biologic drugs with complex structures and activities and also underscore the importance of further pharmacologic studies involving animal models and human clinical trials. The U.S. Food and Drug Administration and the European Medicine Evaluation Agency are currently developing guidelines for the acceptance of biosimilar agents including LMWHs. Until such guidelines are complete, generic interchange may not be feasible.

    View details for DOI 10.1055/s-2008-1066026

    View details for Web of Science ID 000255122700007

    View details for PubMedID 18393144

  • In vitro characterization of the neutralization of unfractionated heparin and low molecular weight heparin by novel salicylamide derivatives Jeske, W., Brubaker, A., Liu, D., Youmg, T., Hoppensteadt, D., Iqbal, O., Fareed, J., Walenga, J. M., Bakhos, M. AMER SOC HEMATOLOGY. 2007: 553A

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