Relationship Between Estrogen Receptor Gene Polymorphism And Coronary Heart Disease

Relationship Between Estrogen Receptor Gene Polymorphism and Coronary Heart Disease Abstract Background: The cardiovascular protective mechanism of estrogen has always considered to be mediated by its indirect effect on lipid metabolism. However, recent studies have revealed that the beneficial effects of estrogen cannot be completely explained by alteration in serum lipid levels. Statistic analysis shows that 5O~?5% of the cardiovascular protective effect of estrogen is mediated by non-lipid effects. Many experiments have proved the existence of estrogen receptors in animal and human cardiovascular systems. The protective effects of estrogen mediated by estrogen receptor have been gradually regarded as a significant mechanism. A lot of fundamental experiments and clinical research have demonstrated the ER-mediated effects play a considerable role in cardiovascular protection of estrogen. The estrogen receptor gene presently has three most frequent polymorphisms, PvuII, Xba I and BstU I polymorphisms. Pvu II and Xba I polymorphisms are located in intron 1 which contains enhancer, promoter and other regulatory sequences. Therefore, these two polymorphisms may affect the expression and function of estrogen receptor. Because of this, the research for estrogen receptor polymorphisms is mainly focused on these two types. Now, by studying the relationship between diseases closely associated with estrogen-estrogen receptor and PvuII polymorphism, researchers have proved that PvuI I polymorphism is correlated to the expression and function of estrogen receptor. On this basis, we suggest that estrogen receptor gene polymorphism can probably affect cardiovascular protective effect mediated by estrogen receptor by altering the expression of estrogen receptor. Objective: To investigate into the relationship between estrogen receptor gene and coronary heart disease. Methods: By polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), we analyzed ER gene polymorphism in 84 CHD patients(male=70, female= 14) and 61 control individuals(male=48, female=l 3), and compared distribution of ER genotype in CHD group and -5- control group, and that in different CHD clinical situation, as well as that in 7 patients who suffered from restenosis after PTCA+stent. Based upon this, we compared clinical indexes associated with CHD of the three ER genotypes, including prevalence rate of hypertension and diabetes mellitus, BMI, serum lipid and concentration of fibrinogen. Results: 1. Distribution of the three ER genotypes: (j) There was a significant difference between CHD group and control group in distribution of the three ER genotypes and allele frequency. The proportions of PP genotype and P allele frequency were higher in CHD group than that in control group. @) There was a significant difference between SA (Stable Angina) group and ACS (Acute coronary syndromes) group in distribution of the three ER genotypes and allele frequency. The proportions of PP genotype and P allele frequency were higher in ACS group than that in SA group. @) Of the 7 patients suffering from restenosis after PTCA+stent, 4 (57.14%) were PP, 2(28.57%) were Pp, and 1(14.29%) was pp. 2. A comparison of clinical indexes associated with CHD in the three ER genoty...