Authors: Henry E. Young, Ioannis J. Limnios, Frank Lochner, George McCommon, Lee Anne Cope and Asa C. Black Jr.
This study was designed to test the hypothesis that decellularized pancreatic matrices seeded with adult-derived endogenous stem cells and donor islets provide an optimal environment for islets to secrete insulin in response to a glucose challenge. Adult animals were euthanized following the guidelines of Fort Valley State University-IACUC and Mercer University-IACUC. Adult porcine pancreases were decellularized using a mixture of detergents. Adult rat pancreatic islets were obtained by lipase digestion followed by Ficoll gradient sedimentation. Control cultures consisted of decellularized matrices, clonal populations of naïve adult totipotent and pluripotent stem cell populations, and rat islets, all cultured individually. Experimental groups consisted of islets co-cultured with clonal populations of pluripotent stem cells and totipotent stem cells seeded on decellularized matrices. Control and experimental cultures were challenged with the insulin secretagogue glucose. The control and culture media were removed and stored at -20oC until assayed using a RIA specific for rat insulin. The culture media, containing bovine insulin, were assayed using a RIA specific for rat insulin. No detectable levels of insulin (bovine, rat, human, or porcine) were noted in media only, the stem cell populations or the decellularized matrices, respectively. Native pancreatic islets secreted nanogram quantities of insulin per nanogram of DNA. Pancreatic islets co-cultured with naïve stem cells and matrices demonstrated increased insulin secretion in the range of milligram quantities of insulin per nanogram of DNA, i.e., a 250-fold increase in insulin secretion in response compared to pancreatic islets alone. These studies suggest that native islets in combination with decellularized matrices and adult-derived pluripotent and totipotent stem cells could provide more tissue for pancreatic islet transplants than donor islets alone.
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