Lack of evidence for secretion of plasminogen activator inhibitor-1 by human subcutaneous adipose tissue in vivo

Circulating plasminogen activator inhibitor-1 (PAI-1) levels are elevated i n patients with coronary heart disease and may play an important role in at herothrombosis. Levels are also raised in obese, hypertriglyceridaemic, or insulin-resistant subjects, which predispose people to coronary heart disea se. It is unclear, though, which organ is responsible for PAI-1 secretion, either in health or disease. We measured arteriovenous differences across a subcutaneous adipose tissue bed in 25 subjects without coronary heart dise ase, which, combined with measures of adipose tissue blood flow, provides s ynthetic rates. There was no net increase in levels of PAI-1 activity (medi an change 0.23, interquartile range -0.59, 1.21 IU.L-1, p=0.30) or of PAI-1 antigen (mean change -0.01, SD+/-2.93 ng.mL(-1), p=0.98) in these subjects . Assuming homogeneous production of PAI-1 by all adipose tissue beds, the contribution of adipose tissue to PAI-1 activity is 3.1% (interquartile ran ge, -11.7, +7.0%) and to PAI-1 antigen 1.6% (Interquartile range -14.5, +7. 3 %). Arteriovenous difference of PAI-1 activity and antigen did not relate to measures of obesity, triglyceride, insulin, fatty acids, or circulating concentrations or adipose tissue production of tumour necrosis factor-alph a or interleukin-6. We conclude that, at least in healthy subjects, subcuta neous adipose tissue does not contribute significantly to circulating level s of PAI-1. (C) 1999 Elsevier Science Ltd. All rights reserved.