Enhancement of pancreatic islet cell monolayer growth by endothelial cell matrix and insulin

The roles of glucose and insulin in the promotion of DNA synthesis in pancreatic islet cell monolayers were assessed using a variety of in vitro conditions. Several substrates including collagen, poly-l-lysine, Matrigel, and the extracellular matrix produced by cultured bovine endothelial cells (BCEM) were compared for their ability to promote monolayer growth. Islets grown on BCEM in combination with medium RPMI 1640 supplemented with 22.2 mM glucose or 10 micrograms/ml insulin gave the best results as determined by new DNA synthesis. The new-form monolayers were free of contaminating fibroblasts. These results suggest that insulin is critical to pancreatic islet growth when the cells are attached to biocompatible matrices.