Formation of pseudoislets from human pancreatic cultures.

We have successfully developed a technique for culturing human islet cells obtained from the cadaveric pancreata of children. Within 24-48 h of in vitro culture, collagenase-digested human pancreatic tissue formed epithelioid monolayers. Scattered within these monolayers were insulin-positive cells, as detected by immunocytochemical and dithizone staining. Treatment of the beta cell-containing epithelioid-cell monolayers with EDTA resulted in the formation of spherical cellular clusters, i.e., pseudoislets. These pseudoislets differed from isolated islets of Langerhans in that they showed a more peripheral distribution of insulin-positive cells. Our studies have demonstrated that insulin-positive cells can be detected in monolayers obtained from human pancreata 3-4 weeks after culture. When exposed to varying concentrations of glucose, these cells secreted insulin. The development of this in vitro technique for culturing human pancreatic islet tissue could provide a model for systematically studying in vitro islet function.