RESUMO
OBJECTIVE: ß-Cell turnover and its potential to permit ß-cell regeneration in adult primates are unknown. Our aims were 1) to measure ß-cell turnover in adult nonhuman primates; 2) to establish the relative contribution of ß-cell replication and formation of new ß-cells from other precursors (defined thus as ß-cell neogenesis); and 3) to establish whether there is an adaptive increase in ß-cell formation (attempted regeneration) in streptozotocin (STZ)-induced diabetes in adult nonhuman primates. RESEARCH DESIGN AND METHODS: Adult (aged 7 years) vervet monkeys were administered STZ (45-55 mg/kg, n = 7) or saline (n = 9). Pancreas was obtained from each animal twice, first by open surgical biopsy and then by euthanasia. ß-Cell turnover was evaluated by applying a mathematic model to measured replication and apoptosis rates. RESULTS: ß-Cell turnover is present in adult nonhuman primates (3.3 ± 0.9 mg/month), mostly (~80%) derived from ß-cell neogenesis. ß-Cell formation was minimal in STZ-induced diabetes. Despite marked hyperglycemia, ß-cell apoptosis was not increased in monkeys administered STZ. CONCLUSIONS: There is ongoing ß-cell turnover in adult nonhuman primates that cannot be accounted for by ß-cell replication. There is no evidence of ß-cell regeneration in monkeys administered STZ. Hyperglycemia does not induce ß-cell apoptosis in nonhuman primates in vivo.
