β-Cell Mass and Turnover in Humans

Abstract

OBJECTIVE We sought to establish β-cell mass, β-cell apoptosis, and β-cell replication in humans in response to obesity and advanced age. RESEARCH DESIGN AND METHODS We examined human autopsy pancreas from 167 nondiabetic individuals 20–102 years of age. The effect of obesity on β-cell mass was examined in 53 lean and 61 obese subjects, and the effect of aging was examined in 106 lean subjects. RESULTS β-Cell mass is increased by ∼50% with obesity (from 0.8 to 1.2 g). With advanced aging, the exocrine pancreas undergoes atrophy but β-cell mass is remarkably preserved. There is minimal β-cell replication or apoptosis in lean humans throughout life with no detectable changes with obesity or advanced age. CONCLUSIONS β-Cell mass in human obesity increases by ∼50% by an increase in β-cell number, the source of which is unknown. β-Cell mass is well preserved in humans with advanced aging.