| Part1The Relationship between Estradiol/Testosterone ratio and Coronary Heart Disease Risk Factors in Postmenopausal WomenBackgroud and Objective:The most significant chracactor of coronary heart disease (CHD) is sex differences. However, threre were increasing controversy on the relationship between single estrogen or androgen and the risk factor f CHD. Meanwhile, there has been no study on the role of the E2/T ratio in women with CHD. This study aimed to evaluate the association among the ratio of sex hormones and known risk factors of atherosclerosis in postmenopausal women with CHD.Methods:114controls and124postmenopausal women with CHD were selected for this study. Serum levels of estradiol, testosterone, aromatase, sex hormone-binding globulin(SHBG), lipid-lipoprotein profile and high-sensitivity C-reactive protein were determined.Results:Compared with the control, the E2/T ratio decreased from5.35±2.78to3.88±2.51(P<0.0001). Multiple linear regression analysis showed that the E2/T ratio was negatively associated with total cholesterol, low-density lipoprotein cholesterol (LDL) and the atherogenic index of plasma, but positively associated with high-density lipoprotein cholesterol (HDL) and HDL/LDL (for all, P<0.0001). We found that there was a negative correlation between the E2/T ratio and aromatase (r=-0.192, P=0.032) and a positive correlation between aromatase and SHBG (r=0.938, P<0.0001).Conclusions:The balance of the serum E2/T ratio was broken in the women with CHD, and an imbalanced E2/T ratio showed a strong association with cardiovascular risk factors in postmenopausal women with CHD, which suggests that maintenance of the balance of serum estradiol and testosterone levels may be critical in the treatment and prevention of CHD. Part2The Synergetic Effect of Estradiol and Testosterone on the Impact of Apoptosis in Human Umbilical Vein Endothelial CellsBackgroud and Objective:The basic researches have demonstrated that both estradiol and testosterone can enhance the production of nitric oxide, inhibit the expression of adhering molecular and chemokine, having the protective effect on vascular endothelial cells. Previous research has figure out that there was a positive association between the decreasing estradiol/testosterone ratio and cardiovascular risk factors. Therefore, in the second part, we plan to find out the influence in the endothelial cells under different estradiol/testosterone ratios. In this part, we aimed to explore the best estradiol/testosterone ratios which can significant restore the apoptosis of endothelial cells inducing by CRP, furthermore, find out the mechanism of this effect.Methods:We chose HUVECs as the main subject in the second part of the study. After inducing by CRP, we give different doses and ratios of estradiol and testosterone to restore the effect of apoptosis. Using MTT to analyze the ratio of inhibition of proliferation, and western blot to detect the apoptosis-related protein and cell signaling protein.Results:The result from MTT showed that when treated5×10-8mol/L E2combined with10mol/L-8T (E2/T=5:), the inhibition rate of cell proliferation is significant higher than other groups. Compared with controls, after inducing by CRP, the expression of cleaved caspase3, cleaved PARP and Bax was much higher, however, when we treated5×10-8mol/LE2combined with10-mol/L8T, the expression of above apoptosis related protein was decreased. For the concentration of NO, compared with control, the level of NO was significant lower in CRP group, as well as E2group and T group. But the the level of NO in E2combined with T group had no difference with controls. Meanwhile, E2combined with T group can significantly decreased the phosphorylation of AKT. And when we treated with the inhibition of PI3K, the anti-apoptosis effect of E2combined with T group was gone. Conclusion:This part of research explored the he best estradiol/testosterone ratios which can significant restore the apoptosis of endothelial cells inducing by CRP, that is5x10-8mol/LE2combined with10-8mol/LT (E2/T=5:1). E2combined with T have strong effect of anti-endothelial apoptosis inducing by CRP, enhance the releasing of NO, protecting the function of endothelial cell. What’s more, all the protection effect of E2combined with T is better than E2or T alone. Part3The Synergetic Effect of Estradiol and Testosterone on the Protective Effect on the Early Stage of AtherosclerosisBackgroud and Objective:An increasing number of clinical trials using estrogen replacement therapy for coronary heart disease (CHD) in postmenopausal women failed to demonstrate a reduced rate of coronary heart disease events. Latest research has demonstrated that the estradiol/testosterone ratio, rather than the absolute levels of testosterone, was crucial in modulating the effect of testosterone on atherosclerosis in females. Estradiol replacement alone results in a testosterone deficiency, and causes an imbalance in the physiologic E2/T ratio. Testosterone replacement with estradiol replacement can also have a complementary effect. Thus, we hypothesized that a physiologic dosage of estradiol combined with testosterone may become a new therapeutic strategy in postmenopausal women with CHD. In this study, we aimed to verify the appropriate E2/T ratio in mice with early stage atherosclerosis to investigate whether the appropriate E2/T ratio has beneficial effects on the prevention of the development of atherosclerosis and to give us a theoretical basis for the hypothesis.Methods:We established a maouse model in early stage of atherosclerosis, giving estradiol (1μg/d), testosterone (7μg/d) or estradiol combined testosterone (1μg/d E2+7μg/dT), respectively. Using red O staining and immunohistochemical to analyze the construction of aortic sinus, Transmission electron microscopy to detect the endothelial injury and ELISAto test the serum level of TNF-αand IL-6.Results:In the in vivo study, we verified the beneficial effects of the defined appropriate E2/T ratio in mice with early stage atherosclerosis. We found that replacement therapy with the defined appropriate E2/T ratio had beneficial effects of reducing the lipid lesions, reducing the formation of foam cells, reducing endothelial injury, modulating the coagulation system function and inhibiting inflammation and was significantly more effective than either estradiol or testosterone supplementation alone. Conclusion:The present study demonstrated that estradiol and testosterone have a synergistic effect on early stage atherosclerosis, and replacement therapy with the defined appropriate E2/T ratio can significantly suppress the development of atherosclerosis. Further studies are warranted to delineate the potential mechanisms and to explore the possible therapeutic application of combined E2and T replacement in an appropriate ration in postmenopausal women with CHD. |
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