Fat cell enlargement as an independent marker of insulin resistance in non-diabetic subjects

To examine whether fat cell size in human adipose tissue is independently related to insulin action and adipokine levels, fat cells were prepared from abdominal subcutaneous biopsies of 49 type 2 diabetic and 83 non-diabetic subjects and from omental biopsies of 37 non-diabetic subjects. Insulin sensitivity in vivo was assessed with euglycaemic-hyperinsulinaemic clamps. Fat cell enlargement was associated with insulin resistance independently of BMI in non-diabetic patients, but not in diabetic patients. Subcutaneous fat cell size correlated positively with plasma levels of leptin in both groups, but with none of the other adipokines. In non-diabetic subjects, omental fat cell size was negatively correlated with insulin action in subcutaneous, but not omental, fat cells in vitro. The results suggest that once a type 2 diabetes phenotype is established, other factors than fat cell size modulate insulin resistance.

Abstract