PANDER (PANcreatic DERived factor, FAM3B), a newly discovered secreted cytokine, is specifically expressed at high levels in the islets of Langerhans of the endocrine pancreas. To evaluate the role of PANDER in ␤-cell function, we investigated the effects of PANDER on rat, mouse, and human pancreatic islets; the ␤-TC3 cell line; and the ␣-TC cell line. PANDER protein was present in ␣-and ␤-cells of pancreatic islets, insulinsecreting ␤-TC3 cells, and glucagon-secreting ␣-TC cells. PANDER induced islet cell death in rat and human islets. Culture of ␤-TC3 cells with recombinant PANDER had a dose-dependent inhibitory effect on cell viability. This effect was also time-dependent. PANDER caused apoptosis of ␤-cells as assessed by electron microscopy, annexin V fluorescent staining, and flow-cytometric terminal deoxynucleotidyl transferase-mediated dUTP nickend labeling assay. PANDER did not affect cytosolic Ca 2؉ levels or nitric oxide levels. However, PANDER activated caspase-3. Hence, PANDER may have a role in the process of pancreatic ␤-cell apoptosis.

Rapamycin (sirolimus) is a macrolide fungicide with immunosuppressant properties that is used in human islet transplantation. Little is known about the effects of rapamycin on MIN-6 cells and islets. Rapamycin had a dose-dependent, time-dependent, and glucose-independent deleterious effect on MIN-6 cell viability. At day 1, using the MTT method, 0.01 nmol/l rapamycin reduced cell viability to 83 ؎ 6% of control (P < 0.05). Using the calcein AM method, at day 2, 10 nmol/l rapamycin caused a reduction in cell viability to 73 ؎ 5% of control (P < 0.001). Furthermore, 10 and 100 nmol/l rapamycin caused apoptosis in MIN-6 cells as assessed by the transferase-mediated dUTP nick-end labeling assay. Compared with control, there was a 3.1 ؎ 0.6-fold increase (P < 0.01) in apoptosis in MIN-6 cells treated with 10 nmol/l rapamycin. A supra-therapeutic rapamycin concentration of 100 nmol/l significantly impaired glucose-and carbachol-stimulated insulin secretion in rat islets and had a deleterious effect on the viability of rat and human islets, causing apoptosis of both ␣-and ␤-cells.

This report confirms the efficacy of the Edmonton immunosuppressive regimen and indicates that insulin independence can often be achieved by a single transplant of sufficient islet mass.

Recent improvements in isolated islet transplantation indicate that this therapy may ultimately prove applicable to patients with type I diabetes. An obstacle preventing widespread application of islet transplantation is an insufficient supply of cadaveric pancreata. Non-heart-beating donors (NHBDs) are generally not deemed suitable for whole-organ pancreas donation and could provide a significant source of pancreata for islet transplantation. Isolated pancreatic islets prepared from 10 NHBDs were compared with those procured from 10 brain-dead donors (BDDs). The success of the isolation for the two groups was analyzed for preparation purity, quality, and recovered islet mass. The function of NHBD and BDD islets was evaluated using in vitro and in vivo assays. On the basis of the results of this analysis, an NHBD isolated islet allograft was performed in a type I diabetic. The recovery of islets from NHBDs was comparable to that of control BDDs. In vitro assessment of NHBD islet function revealed function-equivalent BDD islets, and NHBD islets transplanted to non-obese diabetic-severe combined immunodeficient (NOD-SCID) mice efficiently reversed diabetes. Transplantation of 446,320 islet equivalents (IEq) (8,500 IEq/kg of recipient body weight) from a single NHBD successfully reversed the diabetes of a type I diabetic recipient. Normally functioning pancreatic islets can be isolated successfully from NHBDs. A single donor transplant from an NHBD resulted in a state of stable insulin independence in a type I diabetic recipient. These results indicate that NHBDs may provide an as yet untapped source of pancreatic tissue for preparation of isolated islets for clinical transplantation.