An Investigation Of The Relationship Among Low Testosterone, Metabolic Syndrome And Carotid Artery Disease And Of The Inflammatory Mechanism In Male Health Screening Population

Background and Objective:The prevalence and severity of cardiovascular disease were higher in man with low testosterone level than that with normal testosterone level. Low testosterone level is one of the risk factor for cardiovascular disease in man. In the diabetes or metabolic syndrome patients, testosterone level was found to correlate negatively with the carotid intima-media thickness and the severity of coronary heart disease. Testosterone supplementation in man has been shown to improve blood sugar, blood pressure and lipid profile, suggesting the protective role of testosterone on cardiovascular disease. The objective of this study was to find out the relationships among low testosterone, metabolic syndrome and cardiovascular disease in male.Method:All male subjects with health screening took carotid color Doppler ultrasonography examination in Huashan hospital, Pudong from August2012to February2013were selected. All the information was recorded including past history of smoking, alcohol consumption, hypertension, diabetes, as well as medication used. Height, weight, waist circumference, hip circumference, blood pressure were measured. Fasting venous blood samples were collected in the early morning. Plasma glucose, lipid profile were analyzed immediately. Plasma glucose was measured with glucose oxidase method, lipid profile (triglycerides, total cholesterol, high density lipoprotein, low density lipoprotein) with standard biochemical method. Seperated serum,kept in the-35℃refrigerator in eppendorf tube, was for the detection of total testosterone (TT), free testosterone (FT) and sex hormone binding globulin(SHBG) with immunochemical method. Aloka-alpha-10color Doppler ultrasonic diagnostic apparatus was used for evaluation of carotid artery intima-media thickness in6sites for each side, and totally12sites bilaterally. The definition of intima-media thickness is any site of carotid artery intima-media greater than or equal to1mm, and the plaque is defined as a localized protrusion of the internal part of the vessel wall into the lumen of50%of the surrounding IMT value. According to the results of carotid artery color Doppler ultrasound detection, all enrolled subjects were divided into three groups as follows:1) without intimal thickening or plaque formation (CA0group);2) with intimal thickening and without plaque formation (CA1group);3) with plaque formation only or accompanied by intimal thickening (CA2group). The combination of the latter two was defined as carotid artery disease group (CAd group). All the data was statistically analysed with SPSS17.0, t test and one-way ANOVA (LSD test) for the differences in clinical characteristics among groups, Pearson correlation analysis or spearman correlation analysis for the linear relationship of each index, multiple linear correlation analysis for the risk factors of carotid artery disease and metabolic syndrome.Result:118cases were collected.4cases were excluded (One case of Hyperthyroidism, one case of tumor, two cases of hormones using). A total of114cases were enrolled.1) The percentage of carotid artery disease was34.2%among114cases. The age, BMI, plasma glucose, HbAlc and triglyceride were significantly higher in the CAd group compared with those in the CAO group, while free testosterone and high density lipoprotein were significantly lower in CAd group (P<0.05) 2) IMT of CA2group and CA1group were significantly higher than CAo group (1.020±0.231mm、0.781+0.090mm、0.601±0.085mm respectively, all P<0.01). IMT in the CA2group was significantly higher than that in the CA; group (P<0.01).3) Free testosterone was negatively correlated with IMT (r=-0.208, P<0.05) and the severity of carotid artery disease (r=-0.297, P<0.01). Free testosterone was significantly lower in CA2group than in CA0group (72.47±17.65pg/ml vs83.77±18.51pg/ml respectively, P<0.01). There is no significantly difference between CA2group and CA1group or between CA1group and CAo group.4) The percentage of the metabolic syndrome was52.6%. Total testosterone, free testosterone is gradually reduced with the increase of the metabolic components. There is no correlation between SHBG and metabolic components. Compared with control group, total testosterone, free testosterone and SHBG were significant lower in metabolic syndrome group(all P<0.01).5) Total testosterone was significantly negatively correlated with waist circumference(r=-0.279, P<0.01), triglycerides(r=-0.219, P<0.05), systolic blood pressure (r=-0.247, P<0.01), diastolic blood pressure (r=-0.293, P<0.01) and blood glucose (r=-0.209, P<0.05);Free testosterone was significantly negatively correlated with waist circumference (r=-0.225, P<0.05), triglycerides (r=-0.259, P<0.01) and blood glucose (r=-0.359, P<0.01), while positively correlated with high-density lipoprotein (r=0.339, P<0.01);SHBG was negatively correlated with waist circumference (r=-0.254, P<0.01), triglycerides (r=-0.194, P<0.05)6) The severity of carotid artery disease was positively correlated with triglycerides (r=0.214, P<0.05) and blood glucose (r=0.243, P<0.01), while negatively correlated with high density lipoprotein (r=-0.269, P<0.01)7) After adjustment for age, waist circumference, blood glucose, blood pressure and blood lipids, the severity of carotid artery disease had no significant correlation with free testosterone or total testosterone.8) After adjusting for age, smoking and alcohol consumption, free testosterone was independently associated with the metabolic syndrome (P=-0.062, P<0.01)Conclusion:1) This study suggested that low testosterone level is correlated with carotid artery disease, but after multiple linear regression analysis, testosterone was not an independent risk factor for male carotid artery disease, might be biased by the small sample size. 2) Low testosterone was correlated to components of metabolic syndrome. Multiple linear regression analysis showed that testosterone was an independent risk factor for the metabolic syndrome in males. Background and Objective:Our previous studies have shown that testosterone level was negatively correlated with components of metabolic syndrome and severity of carotid artery disease, suggesting the protective effect of testosterone on endothelial cells. Inflammatory reaction plays a most important role in the endothelial dysfunction. Chemerin, a newly discovered adipokine in2007, involves in the immune and inflammatory response, suggesting that chemerin might be a pro-inflammatory cytokines, but the relationship between chemerin and testosterone have not been reported. In addition, tumor necrosis factor a (TNFa), interleukin-6(IL-6), vascular cell adhesion molecule1(VCAM1), tissue factor pathway inhibitor1(TFPI-1) were inflammatory factors as well with close relation to the process of atherosclerosis. VCAM1and TFPI-1were synthesis and secretion by the endothelial cells, meanwhile, TNFa receptor, IL-6receptor and chemerin receptor were express in the surface of endothelial cells The objectives of our study were: 1) to explore the relationship between the inflammatory factors chemerin level and the severity of carotid artery disease in the male health screen population.2) to investigate the impact of testosterone on the gene transcription of inflammatory factors or inflammatory factor receptor in endothelial cell.Method:1) We selected male subjects who took health screen and carotid color doppler ultrasonography examination in Huashan Hospital, Pudong, as stated above, from August2012to February2013. Fasting blood samples were collected in the early morning and serum in eppendorf tube was stored in the-35℃refrigerator. Aloka-alpha-10color Doppler ultrasonic diagnostic apparatus was used for carotid ultrasound detection. The level of chemerin is determined by ELISA, and total testosterone, free testosterone and sex hormone binding globulin determined by Immune biochemical method. According to the criterial described above, all enrolled males were divided into CA0group, CA1group and CA2group, as well as the CAd group for the combination of CA1group and CA2group.2) Human umbilical endothelial cells passages3to8were cultured in vitro. The testosterone concentration of different intervention group was3×10-5mmol/1,3X10-6mmol/1,3×10-7mmol/1,3×10-8mmol/l and3×10-9mmol/1, and same amount of ethanol for the control, with triplicate and three runs for each. RNA was extracted after24h intervention, RT-PCR was for the detection of gene transcription of VCAM-1, TFPI-1, IL-6receptor(gp130), TNF alpha receptor and chemerin receptor. All the data was statistically analysed with SPSS17.0, t test and one-way ANOVA (LSD test) for the differences in clinical characteristics among groups, Pearson correlation analysis or spearman correlation analysis for the linear relationship of each index.Results:1) Chemerin level was positively correlated with the severity of carotid artery disease (r=0.23, P<0.05). Compare with CA0group, chemerin was significantly higher in CA2group (76.724±17.544ng/ml vs91.428±16.401ng/ml, P<0.05); there was no significant difference between other groups.2) Chemerin level was negatively correlated with total testosterone (r=-0.26, P<0.05)3) Compared with the control group, testosterone, with physiological dosage (3×10-7mmol/l) or beyond (3×10-6mol/1、3×10-5mmol/l), significantly inhibited gene expression of VCAM1. 4) Compared with the control group, testosterone, with physiological dosage (3×10-7mmol/1) or beyond (3×10-6mmol/l、3×10-5mmol/1), significantly upregulated gene expression of TFPI-1(all P<0.05).5) Testosterone beyond physical dosage (3×10-6mmol/1、3×10-5mol/l) significantly upregulated gp130gene transcripts.6) Gene expression of CMKLR1and TNFR1showed no significant change in groups.Conclusion:1) Chemerin level was significantly positively associated with the severity of carotid artery disease and negatively related with testosterone;2) Testosterone could decrease gene transcription of VCAM-1, increase gene transcription of TFPI-1in endothelial cells, suggesting that testosterone might play the protective role on the endothelial cells; The upregulation effect of gp130gene transcription by testosterone needs further study in the vascular disease; Testosterone showed no significant impact on chemerin receptor or TNFα receptor.