Association Of Catechol-o-methyltransferase Gene Polymorphism And Methylation With Smoking And Carotid Atherosclerosis

Objective To study the relationship between smoking and the polymorphism and methylation of COMT rs4680,and to explore the relationship between the methylation of COMT gene and carotid atherosclerosis.Method A total of 130 middle-aged and elderly males admitted to the health department of our hospital from June 2018 to November 2019 were selected,including 64 in the smoking group and 66 in the control group.According to the results of carotid ultrasound,the smoking population was divided into a smoking hardening group(38 cases),smoking non-sclerosing group(26 cases).Scale data and 5ml venous blood samples were collected from all subjects.Genomic DNA from blood samples of all subjects was extracted to detect the genotype of COMT rs4680.At the same time,Illumina Hiseq platform was used to conduct high-throughput sequencing in 2×150bp double-end sequencing mode,and the genomic methylation levels of all subjects were detected.SPSS22.0 was used for statistical processing,and shapiro-wilk's was used for normality test.For normal (?) ± s)is used for analysis;For the skewed distribution data,the median(quartile spacing)was used for analysis by mann-whitney rank sum test.The qualitative data were expressed by frequency(frequency),and the fit test of the qualitative data and the Hardy-Weinberg genetic equilibrium law was analyzed by chi-square test.P<0.05 was considered statistically significant.Results 1.There was no significant difference in age and education between the smoking group and the control group(P>,0.05).2.Hardy-weinberg software verified that the COMT genotype and allele frequency distribution were consistent with HWE rule(P>,0.05).The frequency distribution of COMT genotype in 130 subjects was 55.4% for GG genotype,33.8% for GA genotype and 10.8% for AA genotype.Allele G was 72.3% and allele A was 26.7%.The results showed that there was no significant difference in the distribution of COMT rs4680 genotype and allele frequency between the smoking group and the control group(P>,0.05).3.The mean methylation degree of the 32 CpG sites of COMT gene in the smoking group was higher than that in the control group,and the difference was statistically significant(P<0.05).The methylation status of 32 CpG sites of COMT gene in smoking group and control group was analyzed.The methylation levels of CpG62 and CpG81 in the smoking group were higher than those in the control group,and the difference was statistically significant(P<0.05).Further analysis showed that the methylation degree of CpG32,CpG35,CpG37,CpG39,CpG51,CpG70,CpG83,CpG89,CpG94,CpG114,CpG119,CpG121,CpG126,CpG147,CpG154,CpG158,CpG164,CpG170,Cp G185,CpG190,CpG196,CpG205,CpG211 and CpG214 in the smoking group was higher than that in the control group.The methylation levels of Cp G66,CpG124 and CpG131 in the smoking group were lower than those in the control group,but the difference was not statistically significant(P>,0.05).4.Linear regression analysis of the COMT gene polymorphism site and methylation fragment site showed that there was no significant correlation between rs4680 polymorphism and COMT methylation(P>,0.05).5.The sclerosis of non smoking group and non smoking group of hardening COMT gene in 32 CpG loci degree of methylation analysis,non smoking sclerosis group CpG COMT gene loci average degree of methylation was(0.0092 + 0.0033)%,not smoking not sclerosis group the CpG COMT gene loci of the average degree of methylation was(0.0087 + 0.0027)%,two groups of CpG COMT gene loci average degree of methylation differences have no statistical significance(P > 0.05).The CpG62 and CpG81 loci of COMT genes in the non-smoking group and the non-smoking group showed that the mean methylation degree of CpG62 in the non-smoking group was(0.0068±0.0039)%,and that of CpG62 in the non-smoking non-hardening group was(0.0072±0.0030)%.The mean methylation degree of CpG81 in the non-smoking group was(0.0102±0.0046)%,while that in the non-smoking and non-smoking group was(0.0099±0.0041)%.There was no statistically significant difference in the methylation degree of CpG62 and CpG81 between the two groups(P>0.05).Conclusion 1.In this study,COMT gene and its 32 methylation sites were detected in middle-aged and elderly people,and it was found that the methylation of COMT gene was related to smoking,and the methylation levels of CpG62 and CpG81 in smokers were higher than those in non-smokers,which had not been reported in other studies.2.The present study did not find a correlation between COMT rs4680 polymorphism and smoking,nor between COMT rs4680 methylation and carotid atherosclerosis,and the sample size could be expanded for further study.