Physiological testosterone stimulates tissue plasminogen activator and tissue factor pathway inhibitor and inhibits plasminogen activator inhibitor type 1 release in endothelial cells (1).(Clinical report)

Abstract: There is a striking gender difference in atherosclerotic vascular disease. For decades, testosterone was considered detrimental to the cardiovascular system. Recent studies, however, have presented some alternative results. The aim of this study was to evaluate the effect of testosterone, using physiological and supraphysiological concentrations, on antigen and mRNA levels of tissue plasminogen activator (tPA), plasminogen activator inhibitor type 1 (PAI-1), and tissue factor pathway inhibitor (TFPI) released by human umbilical vein endothelial cells and to investigate the cellular mechanism. Cells within 2-3 passages were cultured in 25 [cm.sup.2] flasks or plated onto 96-well plates with a density of about 1 x [10.sup.5] cells/mL as recommended. The cells were incubated in the presence or absence of testosterone (3, 30, 3 x [10.sup.3], 3 x [10.sup.4] nmol/L) for 48 h. Levels of tPA, PAI-1, and TFPI antigen were assayed with ELISA kits. Reverse transcriptase PCR was carried out to detect tPA, PAI-1, and TFPI mRNA levels. Cells were incubated in androgen-receptor antagonist (flutamide 10 [micro]mol/L) or aromatase inhibitor (aminoglutethimide 50 [micro]mol/L) for 3 h, and then the experiments were repeated. Testosterone at a physiologic concentration (30 nmol/L) increased the antigen levels of tPA and TFPI significantly (P < 0.05). However, tPA and TFPI levels were markedly reduced (P < 0.05) at a larger dose (3 x [10.sup.4] nmol/L). On the other hand, PAI-1 antigen levels decreased significantly at the testosterone concentrations ranging from 3 to 3 x [10.sup.4] nmol/L (P < 0.05). The change in the levels of tPA and TFPI were reflected in the corresponding change in mRNA levels. Flutamide attenuated the effect of testosterone at physiological concentration (30 nmol/L). The results demonstrated that testosterone at physiological concentrations may have a beneficial influence on the haemostatic system through enhancement of anticoagulant activity, resulting from stimulation of TFPI and tPA expression and inhibition of PAI-1 secretion by the endothelium.

Key words: coronary heart disease (CHD), testosterone, tissue plasminogen activator (tPA), plasminogen activator inhibitor type 1 (PAI-1), tissue factor pathway inhibitor (TFPI), human umbilical vein endothelial cell (HUVEC).

Resume : Il existe une difference de genre importante relativement a l'atherosclerose vasculaire. Depuis des decennies, la testosterone a ete consideree dommageable pour le systeme cardiovasculaire. Des etudes recentes, cependant, ont presente quelques resultats differents. Le but de cette etude etait d'evaluer l'effet de la testosterone en concentrations physiologiques et supra-physiologiques sur la quantite de tPA, de PAI-1 et de TFP1 liberes et d'ARNm produit par les cellules endotheliales du cordon ombilical (HUVEC) et d'investiguer le mecanisme cellulaire qui en est responsable. Les cellules de moins de 2-3 passages ont ete cultivees dans des flacons de 25 [cm.sup.2] ou ensemencees dans des plaques a 96 puits a une densite d'environ 1 x [10.sup.5] cellules/mL, tel que recommande. Les cellules ont ete incubees en presence ou en absence de testosterone (3, 30, 3 x [10.sup.3], 3 x [10.sup.4] nmol/L) pendant 48 heures. Les quantites de tPA, de PAI-1 et de TFP1 ont ete mesurees a l'aide de trousses ELISA. Une RT-PCR a ete realisee pour mesurer la quantite d'ARNm de tPA, de PAI-1 et de TFP1. Les cellules ont ete incubees avec un antagoniste du recepteur des androgenes (flutamide 10 [micro]mol/L) ou un inhibiteur d'aromatase (Aminoglutethimide 50 [micro]mol/L) pendant 3 heures et les experiences ont ete repetees. Une concentration physiologique de testosterone (30 nmol/L) a augmente les quantites de tPA et de TFP1 de facon significative (P < 0.05). Cependant, la quantite de tPA et de TFP1 etait fortement reduite (P < 0.05) a plus forte dose (3 x [10.sup.4] nmol/L). En revanche, les quantites de PAI-1 ont diminue de facon significative a des concentrations de testosterone allant de 3 a 3 x [10.sup.4] nmol/L (P < …