Adipose Tissue Expandability and Type 2 Diabetes

Adipose tissue (AT) expands in response to excessive energy intake by hyperplasia or hypertrophy. While hyperplasia is associated with preservation of insulin sensitivity, hypertrophic AT exerts a number of metabolic defects. The mechanisms by which hyperplasia is suppressed at the expense of AT hypertrophy remain unknown, but it is expected that the hypertrophy of adipocytes is primarily driven by insufficient recruitment and differentiation of available preadipocytes. The limitation of hyperplasia occurs already in non-obese healthy subjects who are genetically predisposed to Type 2 Diabetes. Using these and control subjects, the LIMEX project aims to analyze the mechanisms of AT expandability. The project will combine in vivo characterization of AT and in vitro studies on human preadipocytes derived from AT biopsies obtained during clinical study. In vitro, proliferation, adipogenesis and lipogenesis of adipose cells will be monitored and these properties will be related to the degree of AT hypertrophy in vivo, insulin sensitivity and genetic predisposition to metabolic complications.

Inclusion criteria

• healthy non-obese men
• subject has genetic predisposition for T2DM- i.e. two first-degree relatives (parents, siblings) or one first-degree relative and two second-degree relatives with type 2 diabetes (grandparents, uncle, aunt) diagnosed with T2DM OR
• subject without any family history of T2DM.

Exclusion criteria

• any prior history of obesity
• elevated triglyceride concentration (above 1.7 mmol/l)
• hypertension
• thyroid or other endocrine disease
• smoking
• drug abuse