FUNCTIONAL-STUDIES OF RAT, PORCINE, AND HUMAN PANCREATIC-ISLETS CULTURED IN 10 COMMERCIALLY AVAILABLE MEDIA

There have been no extensive studies investigating the effect of tissu e culture media on the in vitro functional characteristics of rat, por cine and human Islets of Langerhans. We therefore aimed to compare ten commercially available tissue culture media on the basis of their abi lity to maintain islet viability. Following isolation, islets were cul tured free-floating in the ten media (RPMI 1640-11mM glucose (control) , RPMI 1640-2.2mM glucose, Dulbecco's MEM, TCM 199, CMRL 1066, Iscove' s MEM, Waymouth's MEM, Serum-Free medium, Ex-cell 300, Ham's F-12) and viability was assessed after 24 hr, 3 days, and 7 days on the basis o f macroscopic appearance, cell membrane integrity, and insulin secreti on in response to glucose stimulation both by dynamic incubation and b y perifusion. Each islet species demonstrated physiological insulin re lease characteristics in all media-however, it was possible to disting uish between the media by comparing the stimulation indices calculated from the insulin release studies. Significantly higher stimulation in dices were produced in Iscove's MEM for rat islets, in Ham's F-12 for porcine islets and in CMRL 1066 for human islets. Over the entire cult ure period a significant deterioration in function was observed in all species cultured in the control media, although this was reversed whe n islets were cultured in the optimal media. Furthermore, in the case of porcine and human islets a significant improvement in function over the seven-day period was noted in the optimal media. In conclusion, o f the commercially available media, the optimal tissue culture medium for rat islets is Iscove's MEM, for porcine islets is Ham's F-12, and for human islets is CMRL 1066.