Regional variation in plasminogen activator inhibitor-1 expression in adipose tissue from obese individuals

High plasma plasminogen activator inhibitor-1 (PAI-1) activity is a frequen t finding in obesity and adipose tissue has recently been suggested to be a sourer of circulating PAI-1 in humans. In the present study, differences i n adipose tissue gene expression and protein secretion rate of PAI-1 betwee n subcutaneous and visceral adipose tissue was analysed in specimens obtain ed from 22 obese individuals. The secretion rate of PAI-1 was two-fold high er in subcutaneous adipose tissue than in visceral adipose tissue (292 +/- 50 vs 138 +/- 24 ng PAI-1/10(7) cells, P < 0,05), In accordance with the se cretion data, subcutaneous adipose tissue contained about three-fold higher levels of PAI-1 mRNA than visceral adipose tissue (2.43 +/- 0.37 vs 0.81 /- 0.12 attomole PAI-1 mRNA/mu g total RNA, P<0,001). PAI-1 secretion from subcutaneous but not from visceral adipose tissue correlated significantly with cell size (r = 0.43, P < 0.05). In summary, subcutaneous adipose tissu e secreted greater amounts of PAI-1 and had a higher PAI-1 gene expression than visceral adipose tissue from the same obese individuals. Bearing in mi nd that subcutaneous adipose tissue is the largest fat depot these finding may be important for the coagulation abnormalities associated with obesity.