title: Subcutaneous adipose cell size and distribution: relationship to insulin resistance and body fat.
abstract: OBJECTIVE
  Metabolic heterogeneity among obese individuals may be attributable to differences in adipose cell size. We sought to clarify this by quantifying adipose cell size distribution, body fat, and insulin-mediated glucose uptake in overweight to moderately-obese individuals.
  
  
  METHODS
  A total of 148 healthy nondiabetic subjects with BMI 25-38 kg/m2 underwent subcutaneous adipose tissue biopsies and quantification of insulin-mediated glucose uptake with steady-state plasma glucose (SSPG) concentrations during the modified insulin suppression test. Cell size distributions were obtained with Beckman Coulter Multisizer. Primary endpoints included % small adipose cells and diameter of large adipose cells. Cell-size and metabolic parameters were compared by regression for the whole group, according to insulin-resistant (IR) and insulin-sensitive (IS) subgroups, and by body fat quintile.
  
  
  RESULTS
  Both large and small adipose cells were present in nearly equal proportions. Percent small cells was associated with SSPG (r = 0.26, P = 0.003). Compared to BMI-matched IS individuals, IR counterparts demonstrated fewer, but larger large adipose cells, and a greater proportion of small-to-large adipose cells. Diameter of the large adipose cells was associated with % body fat (r = 0.26, P = 0.014), female sex (r = 0.21, P = 0.036), and SSPG (r = 0.20, P = 0.012). In the highest versus lowest % body fat quintile, adipose cell size increased by only 7%, whereas adipose cell number increased by 74%.
  
  
  CONCLUSIONS
  Recruitment of adipose cells is required for expansion of body fat mass beyond BMI of 25 kg/m2 . Insulin resistance is associated with accumulation of small adipose cells and enlargement of large adipose cells. These data support the notion that impaired adipogenesis may underlie insulin resistance.
authors.affiliation: Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: T
authors.initials: T
authors.lastname: McLaughlin
authors.forename: C
authors.initials: C
authors.lastname: Lamendola
authors.forename: N
authors.initials: N
authors.lastname: Coghlan
authors.forename: T C
authors.initials: TC
authors.lastname: Liu
authors.forename: K
authors.initials: K
authors.lastname: Lerner
authors.forename: A
authors.initials: A
authors.lastname: Sherman
authors.forename: S W
authors.initials: SW
authors.lastname: Cushman
mesh_terms: D017667:Adipocytes / Q000166:cytology*; D050156:Adipogenesis; D000328:Adult; D001706:Biopsy; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D048429:Cell Size; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000378:metabolism; D050177:Overweight / Q000378:metabolism; D050151:Subcutaneous Fat / Q000166:cytology* / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism
chemical_list: D001786:Blood Glucose; D007328:Insulin; D014280:Triglycerides