Tissue plasminogen activator (T-PA) and plasminogen activator inhibitor (PAI-1) levels in the conditioned medium of cultured porcine brain microvascular endothelial cells.

Vascular endothelial cells are known to produce tissue plasminogen activator (t-PA) and plasminogen activator inhibitor 1 (PAI-1). However, the release kinetics of these substances by brain microvascular endothelial cells (BMEC) is less well known. BMEC prepared from porcine brains using enzymatic digestion and percoll gradient separation was exposed to culture medium containing thrombin (1.0IU/ml), histamine (10 mumol/ml), and TN-alpha (500, 1000, 2000U/ml). The supernatant obtained at respective time points was subjected to ELISA for t-PA, PAI-1 and t-PA-PAI-1 complex. The value of these substances were significantly higher than those of the controls at respective time points. It also proved that t-PA and PAI-1 production by BMEC increases in a parallel fashion. The present study suggests that t-PA production by BMEC cultured under given stimulation increases, however, it is accompanied by concomitant PAI-1 production.