title: Change in β-cell mass in Japanese nondiabetic obese individuals.
abstract: OBJECTIVE
  The aim of this study was to clarify the change in β-cell mass in Japanese obese individuals.
  
  
  METHODS
  We obtained the pancreas at autopsy from 39 lean and 33 obese Japanese nondiabetic individuals (aged 47 ± 13 vs 47 ± 12 y, P = .83, body mass index 20.4 ± 1.6 vs 28.5 ± 3.9 kg/m(2), P < .01). Pancreatic sections were stained for insulin, and β-cell area (%BCA) was measured as the fraction of the β-cell area to the total pancreas area. β-Cell mass was then calculated as the product of %BCA and estimated pancreas weight. β-Cell replication and apoptosis were assessed by double staining for insulin and Ki67 and insulin and single-stranded DNA, respectively. The frequencies of insulin-positive duct cells and scattered β-cells were assessed as the surrogate markers of β-cell neogenesis. The α-cell area (%ACA) was also measured, and the %ACA to %BCA ratio was determined.
  
  
  RESULTS
  There was no increase in β-cell mass in obese individuals compared with lean individuals (0.6 ± 0.4 vs 0.7 ± 0.4 g, P = .12). β-Cell replication, β-cell neogenesis, and β-cell apoptosis were not significantly increased in the presence of obesity. There was no significant difference in %ACA to %BCA ratio between obese and lean individuals (0.91 ± 1.09 vs 0.75 ± 0.51, P = .47).
  
  
  CONCLUSIONS
  There was no increase in β-cell mass and no detectable change in β-cell turnover in Japanese obese individuals.
authors.affiliation: Department of Internal Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
authors.forename: Kinsei
authors.initials: K
authors.lastname: Kou
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Saisho
authors.forename: Seiji
authors.initials: S
authors.lastname: Satoh
authors.forename: Taketo
authors.initials: T
authors.lastname: Yamada
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Itoh
mesh_terms: D000328:Adult; D000368:Aged; D017209:Apoptosis / Q000502:physiology*; D044466:Asian People; D002455:Cell Division / Q000502:physiology; D048429:Cell Size; D005260:Female; D006801:Humans; D050417:Insulin-Secreting Cells / Q000473:pathology*; D007564:Japan; D008875:Middle Aged; D009765:Obesity / Q000473:pathology* / Q000503:physiopathology; D009929:Organ Size / Q000502:physiology; D010179:Pancreas / Q000473:pathology* / Q000503:physiopathology; D012189:Retrospective Studies