Subcutaneous abdominal, but not femoral fat expression of plasminogen activator inhibitor-1 (PAI-1) is related to plasma PAI-1 levels and insulin resistance and decreases after weight loss

Aims/hypothesis. Abdominal fat produces plasminogen activator inhibitor-1 ( PAI-1) and could contribute to increased plasma PAI-1 values in human obesi ty associated with insulin resistance. Femoral fat, which is not associated with insulin resistance, is thought to be metabolically different from the abdominal fat. This study aimed to assess PAI- I expression in these two f at territories in obese and lean subjects and to determine if concomitant c hanges of plasma and adipose tissue PAI- I values occur after weight reduct ion. Methods. In 24 obese and 16 lean subjects. PAI- I expression in abdominal a nd femoral subcutaneous fat, plasma PAI-1, insulin, triglyceride concentrat ions and insulin resistance were determined at the start of the study and i n obese subjects after a 3-month weight reduction programme as well. Results. PAI-1 mRNA content in the abdominal subcutaneous fat was higher in obese than in lean subjects and positively correlated with plasma PAI- I v alues (p < 0.01) and markers of insulin resistance (p < 0.05). In 18 obese subjects, re-examined after successful dieting, PAI-1 mRNA content decrease d in the abdominal subcutaneous fat along with plasma PAI-1. However, the a bsolute changes of these two variables were not associated. In contrast, PA I-I mRNA content in the femoral subcutaneous fat did not differ between lea n and obese subjects, was not associated with plasma PAI-1 values or with m arkers of insulin resistance, and did not change after weight loss. Conclusion/interpretation. Only the abdominal, but not the femoral subcutan eous fat PAI- I expression is a potential contributor to increases in plasm a PAI-1 in obesity. Both plasma and abdominal subcutaneous fat PAI-1 values decreased significantly after weight reduction, although their absolute ch anges were not associated.