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Publications (6)6.69 Total impact

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    ABSTRACT: The mechanism of testosterone inducing the tissue factor pathway inhibitor (TFPI) in protecting against thrombosis is unknown. We aimed to elucidate the mechanisms involved in the induction by observing, in human umbilical vein endothelial cells (HUVECs), the phosphorylation of mitogen-activated protein kinases (MAPKs), a major cell signaling system. The level of testosterone regulating several signaling pathways, including extracellular signal-regulated kinases 1/2 (ERK1/2), c-Jun-N-terminal kinase (JNK), and p38 MAPK, was measured by western blot in HUVECs. ELISA and quantitative real-time reverse transcriptase-PCR were used to analyze TFPI expression after blocking ERK1/2 (with PD98059) or JNK (with SP600125) pathway in HUVECs. Testosterone-induced a rapid phosphorylation of ERK1/2, JNK and p38 MAPK in HUVECs, which could not be inhibited by androgen receptor antagonist flutamide. Blocking ERK1/2 or JNK pathway could significantly impair testosterone-induced TFPI at both translational and transcriptional levels in HUVECs. Testosterone at a physiological concentration may help to prevent thrombosis development by stimulating TFPI expression in HUVECs, partly through the ERK1/2 and JNK MAPK pathway.
    Blood coagulation & fibrinolysis: an international journal in haemostasis and thrombosis 05/2010; 21(5):420-4. · 1.25 Impact Factor
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    ABSTRACT: We have observed earlier that testosterone at physiological concentrations can stimulate tissue factor pathway inhibitor (TFPI) gene expression through the androgen receptor in endothelial cells. This study further investigated the impact of testosterone on TFPI levels in response to inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha). Cultured human umbilical vein endothelial cells were incubated in the presence or absence of testosterone or TNF-alpha. TFPI protein and mRNA levels were assessed by enzyme-linked immunosorbent assay and quantitative real-time reverse transcription polymerase chain reaction. To study the cellular mechanism of testosterone's action, nuclear factor-kappa B (NF-kappaB) translocation was confirmed by electrophoretic mobility shift assays. We found that after NF-kappaB was activated by TNF-alpha, TFPI protein levels declined significantly by 37.3% compared with controls (P < 0.001), and the mRNA levels of TFPI also decreased greatly (P < 0.001). A concentration of 30 nmol L(-1) testosterone increased the secretion of TFPI compared with the TNF-alpha-treated group. NF-kappaB DNA-binding activity was significantly suppressed by testosterone (P < 0.05). This suggests that physiological testosterone concentrations may exert their antithrombotic effects on TFPI expression during inflammation by downregulating NF-kappaB activity.
    Asian Journal of Andrology 01/2009; 11(2):266-71. · 2.53 Impact Factor
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    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(2) flasks or plated onto 96-well plates with a density of about 1 x 10(5) cells/mL as recommended. The cells were incubated in the presence or absence of testosterone (3, 30, 3 x 10(3), 3 x 10(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 micromol/L) or aromatase inhibitor (aminoglutethimide 50 micromol/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(4) nmol/L). On the other hand, PAI-1 antigen levels decreased significantly at the testosterone concentrations ranging from 3 to 3 x 10(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.
    Biochemistry and Cell Biology 04/2007; 85(2):246-51. · 2.92 Impact Factor
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    ABSTRACT: To investigate the relationship between homocysteine (Hcy) and the fibrinolytic system in acute myocardial infarction (AMI) and human umbilical vein endothelial cells (HUVEC). Cultured HUVEC was divided into 10 groups (0, 10, 50, 200, 500 micromol/L Hcy with or without 15 micromol/L of folic acid). There were 53 patients of acute myocardial infarction (AMI) and 48 healthy controls. The plasminogen activator inhibitor-1 (PAI-1) and activator of plasminogen (tPA) antigen levels in HUVEC's supernatant and plasma were measured with Elisa kit. Concentration of plasma Hcy was measured by reverse-phase high-performance liquid chromatography with precolumn derivatization and fluorometric detection in the patients and healthy controls. Total RNA was extracted using the guanidinium isothiocyanate method. The semi-quantification of PAI-1 and tPA mRNA in HUVEC was carried out by reverse transcriptase-polymerase chain reaction (RT-PCR). (1) PAI-1 mRNA and secreted protein levels were both significantly enhanced by Hcy at the concentration of 500 micromol/L, compared with the control group (P < 0.05). (2) The tPA mRNA and antigen levels were decreased significantly at concentration of 500 micromol/L of Hcy, compared with that of 10 micromol/L Hcy (P < 0.05), but compared with the control group (0 micromol/L), the tPA mRNA and antigen levels of 10 micromol/L of Hcy were much higher (P < 0.05). (3) The addition of folic acid reduced PAI-1 but increased tPA at both mRNA and protein levels, which were both obvious at concentrations of 500 micromol/L Hcy, compared with only Hcy group (P < 0.05). (4) Hcy, tPA, and PAI-1 antigen levels were increased in AMI group. Hcy is a independent risk factor of AMI (P < 0.05). There weren't significant correlation between Hcy and tPA or Hcy and PAI-1 in both groups (P > 0.05), although the coefficient correlation was higher in patients than in controls. These results suggested that hyperhomo-cysteinemia increased the incidence of thrombotic disease, which may be caused by decreasing the activity of fibrinolytic system, whereas, folic acid may be protective against the toxic action of Hcy.
    Zhonghua xin xue guan bing za zhi [Chinese journal of cardiovascular diseases] 09/2005; 33(9):810-4.
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    ABSTRACT: In order to elucidate the relationship between homocysteine (Hcy) and the fibrinolytic system, we examined the effect of Hcy on tissue- type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) gene expression in human umbilical vein endothelial cells (HUVEC) in vitro. Total RNA was extracted from HUVEC exposed to physical and pathological concentrations of Hcy (0, 10, 50, 200, 500 micromol/L ) for 24 hours, using the guanidinium isothiocyanate method. The semi-quantification of tPA and PAI-1 mRNA in HUVEC was carried out by reverse transcriptase-polymerase chain reaction (RT-PCR). PAI-1 mRNA levels was enhanced by Hcy at concentrations of 500 micromol/L of Hcy, compared with that of 0 micromol/L Hcy (P < 0.05). The mRNA expression of tPA, however, was significantly decreased at concentrations of 500 micromol/L Hcy, compared with that of 10 micromol/L Hcy (P < 0.05), but compared with the control group, the tPA level of 10 micromol/L Hcy was much higher (P < 0.05). Hyperhomocysteinemia increases the incidence of cardio cerebral vascular disease, which may be caused by decreasing the activity of fibrinolytic system, whereas, the physiological concentration of Hcy may be decreased the incidence by enhancing the activity of fibrinolytic system.
    Zhongguo ying yong sheng li xue za zhi = Zhongguo yingyong shenglixue zazhi = Chinese journal of applied physiology 11/2004; 20(4):363-6.
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    ABSTRACT: To investigate the influences of testosterone with varied concentrations on the functions of HUVEC. Human umbilical vein endothelial cells within 2-3 passages were cultured with testosterone (3 x 10(-10) to 3 x 10(-8), 3 x 10(-6), 3 x 10(-5) mol/ L), and the control confluent cells were cultured in the same medium without steroid. MTT experiment was repeated for 7 days to investigate each groups' cell proliferation. The values of NO were tested as recommended. The tPA and PAI-1 antigen levels were as- sayed with ELISA Kits. Testosterone at physiologic or lower concentrations (3 x 10(-10) to 3 x 10(-8) mol/L ) had no adverse effect on A490 and NO level, meanwhile, stimulated the secretion of tPA (P < 0.01). However, tPA levels markedly reduced at larger dose (3 x 10(-6) to 3 x 10(-5) mol/L). On the other hand, PAI-1 antigen levels decreased significantly at the testosterone concentrations ranging from 3 x 10(-10) to 3 x 10(-5) mol/L (P < 0.05). Testosterone at physiologically relevant concentrations affectively decreased PAI-1, while increased tPA levels, which suggested that testosterone might have beneficial effects on the Human umbilical vein endothelial cells and cardiovascular system to prevent athemscelrosis.
    Zhongguo ying yong sheng li xue za zhi = Zhongguo yingyong shenglixue zazhi = Chinese journal of applied physiology 11/2004; 20(4):338-41.