Don W. Powell, M.D.
Director, Division of Gastroenterology and Hepatology
Don W. Powell, M.D.
Director, Division of Gastroenterology and Hepatologyh
Program Director, General Clinical Research Center
Professor, Internal Medicine
Professor, Neuroscience and Cell Biology
University of Texas Medical Branch
301 University Blvd.
Galveston, TX 77555-0764
Dr. Powell is currently the Director of the UTMB Institute for Translational Sciences-Clinical Research Center and Director of the Division of Gastroenterology and Hepatology in the Department of Internal Medicine at The University of Texas Medical Branch (UTMB) in Galveston, where he is the Bassel and Frances Blanton Distinguished Professor of Internal Medicine and Professor, Neuroscience and Cell biology. He directs the NASA Flight Analog Research unit as part of his Clinical Research Center responsibilities. Dr. Powell stepped down from the Chair of Internal Medicine at UTMB in 2002, a position he held for 11 years and he served as Associate Dean for Research from 2002-2006.
Dr. Powell earned his medical degree from the Medical College of Alabama, Birmingham. He completed his residency training at Peter Bent Brigham Hospital in Boston and at Yale-New Haven Community Hospital and completed a Special National Institutes of Health Fellowship in Physiology at Yale University School of Medicine. He was a member of the faculty at University of North Carolina for 20 years, where he was Professor of Medicine and the Chief of the Division of Digestive Diseases and Nutrition and Director the NIH-funded Center for Gastrointestinal Biology and Disease.
He has been funded by the NIH for research in gastrointestinal science for over 40 years. He has served on Study Sections, Councils and Advisory Committees at the NIH, and the editorial boards of numerous medical and scientific journals. He was an Associate Editor of the Cecil Textbook of Medicine, the Yamada Textbook of Gastroenterology, now in its 5th edition, and a new 1st edition text: Principles of Clinical Gastroenterology. He has authored and co-authored over 200 peer-reviewed journal articles, textbooks and chapters, teaching aids, reviews, and editorials. He has been named in numerous issues of Who's Who and named to Best Doctors in America, America's Top Doctors, etc. many times from 1979 to 2011.
Dr. Powell served on the Boards of Directors of the American Board of Internal Medicine (ABIM) from 1996 to 2000 and the Alpha Omega Alpha Honorary Medical Society for 1999 to present. In 1993-1994 he served as President of the American Gastroenterological Association (AGA). In 2001, he was given the AGA Friedenwald Medal in recognition of lifetime achievement in gastroenterology and he received the AGA Mentors Research Scholar Award in 2005. He was honored as a Master of the American College of Physicians in 1999 and was named the Texas Chapter Laureate in 2009. In 2002, he received the John P. McGovern, M.D. Award in Oslerian Medicine from UTMB, and was elected as a Fellow in the American Association for the Advancement of Science (AAAS) in 2003. A scholarship in the UTMB Nursing School and a named lecture has been established by grateful patients to honor Dr. Powell and in 2009 the annual Don W. Powell Lecture was established by the AGA Institute.
Dr. Powell has been awarded NIH funding for over 40years to study mechanisms of intestinal electrolyte transport and, at present, his interest has turned to the immune system control of these processes, COX-2 gene regulation, immunology of mesenchymal cells and colon cancer microenvironment.
Research in the lab focuses upon the biology of intestinal myofibroblasts (IMF), also called instetinal stromal cells.. These cells are members of a family of phenotypically-related cells that include glomerular mesangial cells, renal and pulmonary interstitial fibroblasts and hepatic and pancreatic stellate cells. Located at the interface between the epithelium and lamina propria, IMF modulate information transfer between these tissue compartments and play a pivotal role in immunology, physiology, development, and carcinogenesis of the gastrointestinal tract. These cells are likely to play an important role in the etiology of colon cancer, inflammatory bowel disease (IBD) and immune tolerance. Ongoing projects involve:
- Regulation of cyclooxygenase-2 (COX-2) gene expression in IMFs. This NIH funded research combines biochemical, molecular biological, and histochemical approaches to understand signaling pathways that regulate COX-2 in IMFs. This research is significant since COX-2 expression is observed in IMF during the early stages of colorectal carcinogenesis and the chemopreventive effects of nonsteroidal anti-inflammatory drugs derive from their ability to inhibit synthesis of COX-derived prostaglandins.
- IMF as novel immune regulators. This research combines immunological, molecular biological, and histochemical approaches to understand how IMF interact with immune cells to modulate intestinal inflammation and tolerance to dietary and bacterial antigens present in the intestinal lumen. In collaboration with the laboratory of Dr. Victor Reyes (Microbiology and Immunology) and Dr. Iryna Pinchuck in the Division of Gastroenterology and Hepatology of the Department of Internal Medicine, experiments are being conducted to undersatand how these stromal cells promote mucosal tolerance and how they drive the various classes of T helper cells in inflammatory bowel diseases. . Knowledge derived from these studies will be used to determine defects associated with IMF in IBD and celiac disease.
- IMFs form the stem cell niche for the intestinal epithelium by secreting factors (Wnts, BMPs, various antagonists) and matrix molecules that control stem cell growth. Their role in development and colon cancer is a new area of research in this laboratory.
- Kosinski C, Li VSW, Chan ASY, Zhang J, Ho C, Tsui WY, Chan TL, Mifflin RC, Powell DW, Yuen ST, Leung SY, Chen X. Gene expression patterns of human colon tops and basal crypts and BMP antagonists as in stinal stem cell niche factors. Proc Nat Acad Sci 104:15418-15423, 2007.
- Pinchuk IV, Saada JI, Beswick EJ, Boya G, Qui SM, Mifflin RC, Reyes VE, Powell DW. PD-1 ligand expression by human colonic myofibroblasts/fibroblasts regulates CD4+T cell activity. Gastroenterology 135;1228-1237,2008
- Francoeur C, Bouatrouss Y, Seltana A, Pinchuk IV, Vachon PH, Powell DW, Sawan B, Seidman EG, Bealulieu JF. Degeneration of the pericryptal myofibroblast sheath by proinflammatory cytokines in inflammatory bowel diseases. Gastroenterology 136;268-277, 2009.
- Kosinski C, Stange DE, Xu C, Chan AS, Ho C, Yuen ST, Mifflin RC, Powell DW, Clevers H, Leung SY, Chen X. Indian Hedgehog regulates intestinal stem cell fate through epithelial mesenchymal interactions during development. Gastroenterology 139-893-903, 2010.
- Mittal S, Mifflin R, Powell DW. Cancer stem cells: the other face of Janus. Am J Med Sci. 338:107-12.2009
- Pinchuk IV, Mifflin RC, Saada JI, Powell DW. Intestinal mesenchymal cells. Current Gastroenterol Reports 12: 310-318, 2010.
- Powell DW, Pinchuk IV, Saada JI, Chen X, Mifflin RC. Mesenchymal cells of the intestinal lamina propria. Annu Rev Physiol, 73:213-237, 2011.
- Mifflin RC, Pinchuk IV, Saada JI, Powell DW. Intestinal myofibroblasts: Targets for stem cell therapy. Am J Physiol: Gastrointest and Liver. 2011, In Press.
- Pinchuk IV, Beswick EJ, Saada J, Boya G, Schmidtt D, Raju GS, Brenmoehl J, Rogler G, Reyes VE, Powell DW. Human Colonic Myofibroblasts Promote Expansion of CD4+CD25 Foxp3+Regulatory T Cells. Gastroenterology 2011, In Press
His clinical expertise lies in inflammatory bowel and diarrheal diseases.
- Yamada T, Alpers DH, Kaplowitz N, Kalloo A, Owyang C, Powell DW (eds). Principles of Clinical Gastroenterology 1st Edition, Wiley-Blackwell Publishing, Oxford, UK, 2008.
- Yamada T, Alpers DH, Kaplowitz N, Kalloo A, Owyang C, Powell DW (eds). Textbook of Gastroenterology 5th Edition, Wiley-Blackwell Publishing, Oxford, UK, 2009.
- Yamada T, Alpers DH, Kaplowitz N, Kalloo A, Owyang C, Powell DW (eds). Atlas of Gastroenterology 4th Edition, Wiley-Blackwell Publishing, Oxford, UK, 2009.
- Powell DW. Approach to the patient with diarrhea. In: Yamada T, Alpers DH, Kalloo A, Kaplowitz N, Owyang C, Powell DW (eds), Atlas of Gastroenterology, 4th Edition, Wiley-Blackwell Publishing, Oxford, UK, 34-55, 2009.
- Singal A, Reddy N, Powell DW. Chapter 21, Diarrhea related to non-neoplastic endocrine diseases In: Diarrhea Diagnostic and Therapeutic Advances, Editors: S. Guandalini, H Vaziri, Humana Press, 357-378, 2011.
- Reddy N, Singal A, Powell DW. Chapter 22, Alcohol related diarrhea. In: Diarrhea and Therapeutic Advances, Editors: S Guandalini, H Vaziri, Humana Press, 379-392, 2011