title: β-cell mass and turnover in humans: effects of obesity and aging.
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.
  
  
  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.
authors.affiliation: Larry L. Hillblom Islet Research Center, University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, CA, USA.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Saisho
authors.forename: Alexandra E
authors.initials: AE
authors.lastname: Butler
authors.forename: Erica
authors.initials: E
authors.lastname: Manesso
authors.forename: David
authors.initials: D
authors.lastname: Elashoff
authors.forename: Robert A
authors.initials: RA
authors.lastname: Rizza
authors.forename: Peter C
authors.initials: PC
authors.lastname: Butler
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D005260:Female; D006801:Humans; D050417:Insulin-Secreting Cells / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology*; D010179:Pancreas / Q000166:cytology*; D055815:Young Adult