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April 3, 2007

CONTACT: Karen Kreeger
(215) 349-5658
karen.kreeger@uphs.upenn.edu


Penn Study Points to New Direction for Pancreas Cell Regeneration
Implications for Diabetes, Other Pancreatic Disorders

(PHILADELPHIA) –Replacing faulty or missing cells with new insulin-making cells has been the object of diabetes research for the last decade. Past studies in tissue culture have suggested that one type of pancreas cell could be coaxed to transform into insulin-producing islet cells.

Now, researchers at the University of Pennsylvania School of Medicine have demonstrated that these pancreatic acinar cells do not become insulin-producing cells in an animal model. However, they did show that injured pancreatic cells readily regenerate back into healthy acinar cells, which has implications for treating cancer and inflammation of the pancreas. This study appears in the April issue of The Journal of Clinical Investigation. The research also holds promise for new techniques for pancreas cell manipulation.

The pancreas is made up of two compartments with different functions: the islet compartment of insulin-producing beta cells and the much larger exocrine compartment composed of duct cells and acinar cells that make and deliver enzymes to the intestine for digestion. Diabetes is caused by the failure of the beta cells to make insulin, whereas pancreatic cancer usually originates from the exocrine compartment. Under certain conditions in tissue culture, acinar cells can synthesize insulin as well as amylase, a digestion enzyme.

“These findings have the potential to change the emphasis in diabetic research as far as regenerating the pancreas is concerned,” says lead author Doris Stoffers, MD, PhD, Assistant Professor of Medicine.

Evidence from Stoffers’ group and other groups is pointing to the beta cell itself as the most promising source for generating new beta cells. The focus of research is now shifting toward the direct stimulation of islet cell growth in live animals. In contrast, once acinar cells are removed from the organism and placed into culture, they may have greater potential to change into other cell types, including beta cells. As a result, Stoffers’ animal model and technical approach is currently being used by other groups in the United States, Europe, and China to determine conditions under which acinar cells can take on the features of duct cells and beta cells.

The Penn team engineered mice with a special marker that permanently and selectively labels only pancreatic acinar cells. The mice were then subjected to pancreatic injury by chemicals or surgery. The pancreas was allowed to heal or regenerate itself, and the specific acinar cell marker was followed microscopically in thin slices of pancreatic tissue. “It is very clear that the acinar and islet compartments remain separate during regeneration in a live animal,” says Stoffers.

“Although our work shows that acinar cells do not contribute to the insulin-producing compartment of the pancreas in an animal model, it is possible that other strategies might be successful in generating the islet cells,” says Stoffers. Ongoing research is examining whether acinar cells from the mice used in this study can be induced to make insulin in tissue culture. “The hope is that these acinar cells would continue to make insulin after being transplanted back into the mouse,” says Stoffers.

The American Diabetes Association and the National Institute of Diabetes and Digestive and Kidney Diseases funded the research.

Coauthors of the study are Biva M. Desai, Jennifer Oliver-Krasinski, Diva D. De Leon, Cyrus Farzad, and Nankang Hong, all from Penn along with Steven D. Leach, from the Johns Hopkins University School of Medicine.

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PENN Medicine is a $2.9 billion enterprise dedicated to the related missions of medical education, biomedical research, and high-quality patient care. PENN Medicine consists of the University of Pennsylvania School of Medicine (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System.

Penn's School of Medicine is ranked #2 in the nation for receipt of NIH research funds; and ranked #3 in the nation in U.S. News & World Report's most recent ranking of top research-oriented medical schools. Supporting 1,400 fulltime faculty and 700 students, the School of Medicine is recognized worldwide for its superior education and training of the next generation of physician-scientists and leaders of academic medicine.

The University of Pennsylvania Health System includes three hospitals, all of which have received numerous national patient-care honors [Hospital of the University of Pennsylvania; Pennsylvania Hospital, the nation's first hospital; and Penn Presbyterian Medical Center]; a faculty practice plan; a primary-care provider network; two multispecialty satellite facilities; and home care and hospice.


This release is available online at
http://www.uphs.upenn.edu/news/News_Releases/apr07/pancreas-cell-regeneration.html