Adipocyte morphology and implications for metabolic derangements in acquired obesity

Int J Obes (Lond). 2014 Nov;38(11):1423-31. doi: 10.1038/ijo.2014.31. Epub 2014 Feb 19.


Background: Adipocyte size and number have been suggested to predict the development of metabolic complications in obesity. However, the genetic and environmental determinants behind this phenomenon remain unclear.

Methods: We studied this question in rare-weight discordant (intra-pair difference (Δ) body mass index (BMI) 3-10 kg m(-2), n=15) and concordant (ΔBMI 0-2 kg m(-)(2), n=5) young adult (22-35 years) monozygotic twin pairs identified from 10 birth cohorts of Finnish twins (n=5 500 pairs). Subcutaneous abdominal adipocyte size from surgical biopsies was measured under a light microscope. Adipocyte number was calculated from cell size and total body fat (D × A).

Results: The concordant pairs were remarkably similar for adipocyte size and number (intra-class correlations 0.91-0.92, P<0.01), suggesting a strong genetic control of these measures. In the discordant pairs, the obese co-twins (BMI 30.6 ± 0.9 kg m(-2)) had significantly larger adipocytes (volume 547 ± 59 pl), than the lean co-twins (24.9 ± 0.9 kg m(-)(2); 356 ± 34 pl, P<0.001). In 8/15 pairs, the obese co-twins had less adipocytes than their co-twins. These hypoplastic obese twins had significantly higher liver fat (spectroscopy), homeostatic model assessment-index, C-reactive protein and low-density lipoprotein cholesterol than their lean co-twins. Hyperplastic obesity was observed in the rest (7/15) of the pairs, obese and lean co-twins having similar metabolic measures. In all pairs, Δadipocyte volume correlated positively and Δcell number correlated negatively with Δhomeostatic model assessment-index and Δlow-density lipoprotein, independent of Δbody fat. Transcripts most significantly correlating with Δadipocyte volume were related to a reduced mitochondrial function, membrane modifications, to DNA damage and cell death.

Conclusions: Together, hypertrophy and hypoplasia in acquired obesity are related to metabolic dysfunction, possibly through disturbances in mitochondrial function and increased cell death within the adipose tissue.

Publication types

  • Research Support, Non-U.S. Gov't
  • Twin Study

MeSH terms

  • Adipocytes / metabolism*
  • Adipose Tissue / metabolism*
  • Adult
  • Body Mass Index
  • Body Weight
  • Energy Metabolism
  • Female
  • Finland / epidemiology
  • Gene Expression
  • Gene-Environment Interaction
  • Genetic Predisposition to Disease
  • Humans
  • Longitudinal Studies
  • Male
  • Metabolome*
  • Obesity / complications
  • Obesity / genetics
  • Obesity / metabolism*
  • Twins, Monozygotic*