Thrombin stimulates tissue plasminogen activator release from cultured human endothelial cells.

Abstract

Abstract. The effect of thrombin on the release of tissue plasminogen activator from endothelial cells was studied in primary cultures of human umbilical vein endothelial cells. Tissue plasminogen activator concentration in conditioned medium was measured by a two-site radioimmunometric assay. The addition of increasing concentrations (0.01 to 10 U/ml) of thrombin to confluent cultures produced a saturable, dose-dependent increase in the rate of release of tissue plasminogen activator. A sixfold increase in tissue plasminogen activator concentration (from 2 to 12 ng/ml) occurred after the addition of 1 U/ml thrombin (8 X l0-9 M) to cultures containing 5 X 104 cells/cm2. Enhanced release was not observed until 6 h after thrombin addition, reached a maximum rate of 1.3 ng/ml per h between 8 and 16 h, and then declined to 0.52 ng/ml per h after 16 h. The 6-h lag period before increased tPA release was reproducible and independent of thrombin concentration.

A Model Incorporating Some of the Mechanical and Biochemical Factors Underlying Clot Formation and Dissolution in Flowing Blood

“…We repeat this procedure for tPA generation by endothelial cells, be it constitutive (see control cells in Schrauwen et al (1994a,b), Schrauwen et al (1995), and data for first 6 h in Levin et al (1984)), or (rapid) induced by thrombin (Schrauwen et al, 1995;data in Booyse et al (1986) is the earliest record of this rapid release, but it is qualitative and cannot be reduced to a form that is usable), or induced by fibrin (Kaplan et al, 1989). We neglect the delayed activation of endothelial cells by thrombin which occurs after 6 h (Levin et al, 1984), since we will perform numerical simulations for less than 1 h (see section 'Procedure for Corroboration of Model with Experimental Data').…”

“…We neglect the delayed activation of endothelial cells by thrombin which occurs after 6 h (Levin et al, 1984), since we will perform numerical simulations for less than 1 h (see section 'Procedure for Corroboration of Model with Experimental Data'). Again,…”

“…G C tPA is obtained from the data in Levin et al (1984). Fibrin-induced tPA generation rate is dose dependent.…”

Antithrombotic, procoagulant, and fibrinolytic mechanisms in cerebral circulation: implications for brain injury and protection

“…For example, coordinated induction of both tPA and PAI-1 has been reported with thrombin or basic fibroblast growth factor (bFGF), whereas histamine, activated protein C, and phorbol ester induce tPA alone, and lipopolysaccharide (LPS), transforming growth factor-ß, interleukin-1 (IL-1), or tumor necrosis factor-alpha (TNF-alpha) induce PAI-1 alone. [33,56,76,[102][103][104][105] It has been shown that human systemic endothelial cells in vitro secrete more tPA when exposed to an arterial level of shear stress [26] and pulsatile stretch, [63] whereas PAI-1 secretion remains unaffected. It has been also demonstrated that tPA secretion and tPA mRNA are significantly upregulated after serial passages in culture, whereas the urokinase-type plasminogen activator gene that is normally not expressed in primary culture, becomes quite active at higher passage numbers.…”

Effect of notoginsenoside R1 on the synthesis of tissue-type plasminogen activator and plasminogen activator inhibitor-1 in cultured human umbilical vein endothelial cells.

“…Previous studies have shown that production of plasminogen activators and inhibitors in various cell types is modulated by several compounds; eg, TPA synthesis in ECs is increased by various stimuli, such as thrombin, 4 histamine, 5 butyrate, 6 retinoic acid, 78 and tumor-promoting agents like phorbol 12-myristate 13-acetate. 9 Factors that modulate PAI-1 expression in ECs include lipopolysaccharides, 10 thrombin, 11 interleukin-1, 12 tumor necrosis factor-a, 13 transforming growth factor-/}, basic fibroblast growth factor, 14 and EC growth supplement (ECGS) combined with heparin.…”