Direct attenuation of plasminogen activator inhibitor type-1 expression in human adipose tissue by thiazolidinediones.

Adipose tissue produces substantial amounts of plasminogen activator inhibitor type-1 (PAI-1), an established cardiovascular risk factor. This study evaluated PAI-1 expression in human adipose tissue in response to thiazolidinediones, insulin sensitising drugs activating peroxisome proliferator-activated receptor-gamma (PPAR-gamma). Troglitazone, rosiglitazone, and ciglitazone significantly reduced PAI-1 protein expression in human preadipocytes under basal conditions and after stimulation of the cells with TGF-beta. Pioglitazone had no effect. In human adipocytes all four thiazolidinediones significantly attenuated PAI-1 expression. Signalling appeared to be mediated via PPAR-gamma and effects reflected, at least in part, changes in transcription. Accordingly, patients with insulin resistance may benefit from treatment with thiazolidinediones with respect to diminution of PAI-1 expression in adipose tissue and consequent potential reduction of cardiovascular risk.