Research Summary

Dr. Andrew Posselt, a bariatric and transplant surgeon, is director of the Pancreatic Islet Transplantation Program at UCSF Medical Center. He specializes in adult and pediatric kidney, liver and pancreas transplantation, laparoscopic and open (traditional) bariatric surgery, robotic surgery and performed the first robotic donor nephrectomy at UCSF in May, 2023.

In addition to caring for patients, Posselt conducts research on pancreatic islet cell transplantation, a procedure that can allow people with type 1 diabetes to discontinue insulin therapy. He also investigates mechanisms by which a transplant recipient's body rejects or tolerates tissue from a donor who isn't genetically identical, and he studies the metabolic and biochemical consequences of bariatric surgery.

Posselt earned his medical degree and a doctorate in immunology from the University of Pennsylvania. He completed residencies in internal medicine and general surgery as well as a transplant fellowship at UCSF, before joining the staff in 2003.

Posselt is a member of several professional and honorary societies, and has given presentations on transplant issues related to patient care and research. At UCSF, he supervises residents and fellows in transplant services and general surgery.

Research Funding

  • July 14, 2021 - May 31, 2024 - Vertical Sleeve Gastrectomy for Treatment of NASH: a pilot randomized control , Co-Principal Investigator . Sponsor: NIH, Sponsor Award ID: R01DK128325
  • May 1, 2014 - April 30, 2021 - Treatment of Type I Diabetes by Islet Transplantation into the Gastric Submucosa , Principal Investigator . Sponsor: NIH, Sponsor Award ID: R01DK098581
  • September 30, 2009 - July 31, 2013 - "Advancing Islet Transplant for Type 1 Diabetes Care" , Principal Investigator . Sponsor: NIH, Sponsor Award ID: U01DK085531
  • September 21, 2009 - June 30, 2012 - Effect of Obesity on Long-Term Clinical Outcomes after Kidney Donation , Principal Investigator . Sponsor: NIH, Sponsor Award ID: R21DK078702

Education

PhD, 1993 - Immunology, University of Pennsylvania
M.D., 1993 - School of Medicine, University of Pennsylvania
Residency, - Internal Medicine, University of California, San Francisco

Selected Publications

  1. Downs EM, Eaton A, Witkowski P, Wijkstrom M, Walsh M, Trikudanathan G, Singh VK, Schwarzenberg SJ, Pruett TL, Posselt A, Naziruddin B, Nathan JD, Mokshagundam SP, Morgan K, Lara LF, Gardner TB, Freeman ML, Ellery K, Chinnakotla S, Beilman GJ, Adams D, Ahmad S, Abu-El-Haija M, Bellin MD. Nutritional Risks in Patients Undergoing Total Pancreatectomy Islet AutoTransplantation in the POST Consortium. J Gastrointest Surg. 2023 Sep; 27(9):1893-1902.  View on PubMed
  2. Wisel SA, Posselt AM, Szot GL, Nunez M, Santos-Parker K, Gardner JM, Worner G, Roll GR, Syed S, Kelly Y, Ward C, Tavakol M, Johnson K, Masharani U, Stock PG. A Multi-Modal Approach to Islet and Pancreas Transplantation With Calcineurin-Sparing Immunosuppression Maintains Long-Term Insulin Independence in Patients With Type I Diabetes. Transpl Int. 2023; 36:11367.  View on PubMed
  3. Wu KC, Cao S, Weaver CM, King NJ, Patel S, Kim TY, Black DM, Kingman H, Shafer MM, Rogers SJ, Stewart L, Carter JT, Posselt AM, Schafer AL. Intestinal Calcium Absorption Decreases After Laparoscopic Sleeve Gastrectomy Despite Optimization of Vitamin D Status. J Clin Endocrinol Metab. 2023 01 17; 108(2):351-360.  View on PubMed
  4. Santandreu AG, Taheri-Tehrani P, Feinberg B, Torres A, Blaha C, Shaheen R, Moyer J, Wright N, Szot GL, Fissell WH, Vartanian S, Posselt A, Roy S. Characterization of human islet function in a convection-driven intravascular bioartificial pancreas. Bioeng Transl Med. 2023 Mar; 8(2):e10444.  View on PubMed
  5. Wu KC, Cao S, Weaver CM, King NJ, Patel S, Kingman H, Sellmeyer DE, McCauley K, Li D, Lynch SV, Kim TY, Black DM, Shafer MM, Özçam M, Lin DL, Rogers SJ, Stewart L, Carter JT, Posselt AM, Schafer AL. Prebiotic to Improve Calcium Absorption in Postmenopausal Women After Gastric Bypass: A Randomized Controlled Trial. J Clin Endocrinol Metab. 2022 03 24; 107(4):1053-1064.  View on PubMed
  6. Witkowski P, Philipson LH, Buse JB, Robertson RP, Alejandro R, Bellin MD, Kandeel F, Baidal D, Gaglia JL, Posselt AM, Anteby R, Bachul PJ, Al-Salmay Y, Jayant K, Perez-Gutierrez A, Barth RN, Fung JJ, Ricordi C. Islets Transplantation at a Crossroads - Need for Urgent Regulatory Update in the United States: Perspective Presented During the Scientific Sessions 2021 at the American Diabetes Association Congress. Front Endocrinol (Lausanne). 2021; 12:789526.  View on PubMed
  7. Meier RPH, Kelly Y, Yamaguchi S, Braun HJ, Lunow-Luke T, Adelmann D, Niemann C, Maluf DG, Dietch ZC, Stock PG, Kang SM, Feng S, Posselt AM, Gardner JM, Syed SM, Hirose R, Freise CE, Ascher NL, Roberts JP, Roll GR. Advantages and Limitations of Clinical Scores for Donation After Circulatory Death Liver Transplantation. Front Surg. 2021; 8:808733.  View on PubMed
  8. Nathan JD, Yang Y, Eaton A, Witkowski P, Wijkstrom M, Walsh M, Trikudanathan G, Singh VK, Schwarzenberg SJ, Pruett TL, Posselt A, Naziruddin B, Mokshagundam SP, Morgan K, Lara LF, Kirchner V, He J, Gardner TB, Freeman ML, Ellery K, Conwell DL, Chinnakotla S, Beilman GJ, Ahmad S, Abu-El-Haija M, Hodges JS, Bellin MD. Surgical approach and short-term outcomes in adults and children undergoing total pancreatectomy with islet autotransplantation: A report from the Prospective Observational Study of TPIAT. Pancreatology. 2022 Jan; 22(1):1-8.  View on PubMed
  9. Ku E, McCulloch CE, Roll GR, Posselt A, Grimes BA, Johansen KL. Bariatric surgery prior to transplantation and risk of early hospital re-admission, graft failure, or death following kidney transplantation. Am J Transplant. 2021 11; 21(11):3750-3757.  View on PubMed
  10. Lara LF, Wastvedt S, Hodges JS, Witkowski P, Wijkstrom M, Walsh RM, Singh VK, Schwarzenberg SJ, Pruett TL, Posselt A, Naziruddin B, Nathan JD, Morgan KA, Mitchell R, Kirchner VA, Mokshagundam SL, Hatipoglu B, Gardner TB, Freeman ML, Chinnakotla S, Beilman GJ, Abu-El-Haija M, Conwell DL, Bellin MD, POST study consortium. The Association of Smoking and Alcohol Abuse on Anxiety and Depression in Patients With Recurrent Acute or Chronic Pancreatitis Undergoing Total Pancreatectomy and Islet Autotransplantation: A Report From the Prospective Observational Study of TPIAT Cohort. Pancreas. 2021 07 01; 50(6):852-858.  View on PubMed
  11. Witkowski P, Odorico J, Pyda J, Anteby R, Stratta RJ, Schrope BA, Hardy MA, Buse J, Leventhal JR, Cui W, Hussein S, Niederhaus S, Gaglia J, Desai CS, Wijkstrom M, Kandeel F, Bachul PJ, Becker YT, Wang LJ, Robertson RP, Olaitan OK, Kozlowski T, Abrams PL, Josephson MA, Andreoni KA, Harland RC, Kandaswamy R, Posselt AM, Szot GL, Ricordi C. Arguments against the Requirement of a Biological License Application for Human Pancreatic Islets: The Position Statement of the Islets for US Collaborative Presented during the FDA Advisory Committee Meeting. J Clin Med. 2021 Jun 29; 10(13).  View on PubMed
  12. Witkowski P, Wijkstrom M, Bachul PJ, Morgan KA, Levy M, Onaca N, Chaidarun SS, Gardner T, Shapiro AMJ, Posselt A, Ahmad SA, Daffonchio L, Ruffini PA, Bellin MD. Targeting CXCR1/2 in the first multicenter, double-blinded, randomized trial in autologous islet transplant recipients. Am J Transplant. 2021 11; 21(11):3714-3724.  View on PubMed
  13. Sharpton SR, Terrault NA, Tavakol MM, Posselt AM. Sleeve gastrectomy prior to liver transplantation is superior to medical weight loss in reducing posttransplant metabolic complications. Am J Transplant. 2021 10; 21(10):3324-3332.  View on PubMed
  14. Desai CS, Szempruch KR, Vonderau JS, Chetboun M, Pattou F, Coates T, De Paep DL, Hawthorne WJ, Khan KM, de Koning EJP, Naziruddin B, Posselt A, Schrope BA, Wijkstrom M, Witkowski P, Shapiro AMJ. Anticoagulation practices in total pancreatectomy with autologous islet cell transplant patients: an international survey of clinical programs. Transpl Int. 2021 03; 34(3):593-595.  View on PubMed
  15. Vasu S, Yang JM, Hodges J, Abu-El-Haija MA, Adams DB, Balamurugan AN, Beilman GJ, Chinnakotla S, Conwell DL, Freeman ML, Gardner TB, Hatipoglu B, Kirchner V, Lara LF, Morgan KA, Nathan JD, Posselt A, Pruett TL, Schwarzenberg SJ, Singh VK, Wijkstrom M, Witkowski P, Naziruddin B, Bellin MD. Circulating miRNA in Patients Undergoing Total Pancreatectomy and Islet Autotransplantation. Cell Transplant. 2021 Jan-Dec; 30:963689721999330.  View on PubMed
  16. Trikudanathan G, Elmunzer BJ, Yang Y, Abu-El-Haija M, Adams D, Ahmad S, Balamurugan AN, Beilman GJ, Chinnakotla S, Conwell DL, Freeman ML, Gardner TB, Hatipoglu B, Hodges JS, Kirchner V, Lara LF, Long-Simpson L, Mitchell R, Morgan K, Nathan JD, Naziruddin B, Posselt A, Pruett TL, Schwarzenberg SJ, Singh VK, Smith K, Wijkstrom M, Witkowski P, Bellin MD. Preoperative ERCP has no impact on islet yield following total pancreatectomy and islet autotransplantation (TPIAT): Results from the Prospective Observational Study of TPIAT (POST) cohort. Pancreatology. 2021 Jan; 21(1):275-281.  View on PubMed
  17. Syed SM, Gardner J, Roll G, Webber A, Mehta N, Shoji J, Adelmann D, Niemann C, Braun HJ, Mello A, Yao F, Posselt A, Kang SM, Hirose R, Roberts J, Feng S, Ascher N, Stock P, Freise C. COVID-19 and Abdominal Transplant: A Stepwise Approach to Practice During Pandemic Conditions. Transplantation. 2020 11; 104(11):2215-2220.  View on PubMed
  18. Markmann JF, Rickels MR, Eggerman TL, Bridges ND, Lafontant DE, Qidwai J, Foster E, Clarke WR, Kamoun M, Alejandro R, Bellin MD, Chaloner K, Czarniecki CW, Goldstein JS, Hering BJ, Hunsicker LG, Kaufman DB, Korsgren O, Larsen CP, Luo X, Naji A, Oberholzer J, Posselt AM, Ricordi C, Senior PA, Shapiro AMJ, Stock PG, Turgeon NA. Phase 3 trial of human islet-after-kidney transplantation in type 1 diabetes. Am J Transplant. 2021 04; 21(4):1477-1492.  View on PubMed
  19. Wisneski AD, Carter J, Nakakura EK, Posselt A, Rogers SJ, Cello JP, Arain M, Kirkwood KS, Hirose K, Stewart L, Corvera CU. Ampullary stenosis and choledocholithiasis post Roux-En-Y gastric bypass: challenges of biliary access and intervention. HPB (Oxford). 2020 10; 22(10):1496-1503.  View on PubMed
  20. Roll GR, Posselt AM, Freise J, Baird J, Syed S, Mo Kang S, Hirose R, Szot GL, Zarinsefat A, Feng S, Worner G, Sarwal M, Stock PG. Long-term follow-up of beta cell replacement therapy in 10 HIV-infected patients with renal failure secondary to type 1 diabetes mellitus. Am J Transplant. 2020 08; 20(8):2091-2100.  View on PubMed

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