Morphology, yield and function were studied in cultured islet-like cell clusters (ICC) from 140 human fetal pancreata obtained after abortions of different types performed at 11-23 weeks of gestation (12 by hysterotomy, 75 by mechanical dilation and extraction, and 53 induced with prostaglandin). After collagenase digestion and culture in medium supplemented with 10% human serum, up to 2000 free-floating ICC were formed from a single pancreas. Randomly scattered insulin- and glucagon-immunoreactive cells were found in the medullary part of the ICC. More than 100 ICC developed in 100% of the hysterotomies and 87% of the mechanical abortions, but in only 53% of the prostaglandin-induced abortions. Insulin and glucagon levels in the culture medium decreased rapidly during the first 7 days of culture, but then remained stable for at least 31 days. The hysterotomy-derived ICC responded to 10 mmol/l theophylline plus 20 mmol/l glucose by a 12.2 +/- 3.1 (SEM, N = 7) fold increase in insulin release, as compared with a 5.4 +/- 0.9 fold response of the prostaglandin ICC (N = 16; P less than 0.02). Despite the low proportion of B-cells, (pro)insulin biosynthesis accounted for 10% of the total protein biosynthesis in low (2 mmol/l) glucose. In conclusion, the yield and viability of the ICC were clearly better, if prostaglandin had not been used for the induction of the abortion.
PIP: The morphology, yield, and functional integrity of islet-like cell clusters (ICC) from 140 human fetal pancreata obtained after abortions performed at 11-23 weeks of gestation were examined. The culture method developed for this study was based on the formation of numerous ICC from collagenase-digested fetal pancreata after culture in medium supplemented with human serum. 12 of the abortions were performed by hysterotomy, 75 by mechanical dilatation and extraction, and 53 were induced by prostaglandin. Up to 2000 free-floating ICC were formed from a single pancreas. More than 100 ICC per pancreas were isolated from 100% of the fetuses from hysterotomies and 87% of the fetuses from mechanical abortions, but from only 53% of the tissues from prostaglandin-induced abortions. Insulin and glucagon levels in the culture medium decreased rapidly during the 1st 7 days of culture, but then remained stable for at least 31 days despite the decrease in the number of ICC. Stimulation of the ICC with glucose and theophylline promptly released insulin. Insulin release was stimulated 12.2-fold in hysterotomy-derived ICC, 6.5-fold in ICC from mechanical abortions, and 5.4-fold in ICC from prostaglandin-induced abortions. Despite the low proportion of B cells, insulin biosynthesis accounted for 10% of the total protein biosynthesis in low glucose. This finding suggests that the nonendocrine cells of the ICC were less active and viable than the endocrine ones. Overall, this study demonstrates a clear correlation between the morphologic and functional characteristics of cultured fetal tissue, with the number of ICC reflecting the degree of tissue viability.