Supplementation of islet culture medium with insulin may have a beneficialeffect on islet secretory function

Recent reports suggest that apoptosis resulting from the disruption of the normal cell-matrix relationship (anoikis) during islet isolation could lead to a loss of islet tissue in culture. Insulin is known to have a role in c ell growth and survival, and this study was undertaken to assess any benefi cial effect on islets by supplementing the islet culture medium with insuli n. Human and porcine islets were cultured in medium supplemented with 0, 10 , 100, and 1,000 ng.mL(-1) insulin. Secretory function was assessed by peri fusion at days 1 and 8. The results demonstrated a significant variation in stimulation index between isolations for human islets, but there was no ef fect relating to the concentration of insulin in the medium or time in cult ure. For porcine islets, there was a significant (p < 0.001) improvement in secretory function for islets cultured in 10 and 100 ng.mL(-1) insulin, re lative to 0 and 1,000 ng.mL(-1) insulin. There was no interisolation variat ion or effect of time in culture. In conclusion, the secretory function of porcine islets benefited from the addition of 10 to 100 ng.mL(-1) insulin t o the culture medium, but interisolation variation in human islet secretory function did not allow any specific effect of the insulin to be determined .