Microcarriers: a new approach to pancreatic islet cell culture

Free islet cell suspensions were prepared from isolated fetal rat islets using a modified enzyme dispersion technique. The islet cells were dispensed into a culture flask containing microcarriers (Cytodex) suspended in culture medium RPMI 1640 by a slowly rotating bar magnet. Microscopical examination of the beads showed that the islet cells attached and then progressively proliferated on the surface of the beads as a monolayer. A highly sustained release of insulin from the beads to the medium was observed during the 7 d culture period. The functional viability of the cultured islet cells was further demonstrated by the ability of batches of the cell-coated beads to synthesize insulin and to increase the insulin release in response to an acute challenge (16.7 mmol/l glucose plus 5 mmol/l theophylline). The results suggest that bead microcarriers may provide a new approach to monolayer islet cell culture providing functional monolayers, which can easily be transferred to different test systems and further manipulated.