Associations Between Several Lipid-related Gene Polpmorphisms And Serum Lipids And Ischemic Heart And Cerebrovascular Diseases

Part ⅠASSOCIATION OF ACAT-1RS1044925SNP AND SERUMLIPID LEVELS AND ISCHEMIC HEART ANDCEREBROVASCULAR DISEASESBackground: Acyl-coenzyme A: cholesterol acyltransferase (ACAT) is akey enzyme in cellular cholesterol homeostasis, involved in the cholesterolmetabolish, thus play an important role in serum lipid levels and the progress ofatherosclerosis.The associations between ACAT-1gene and serum lipid levelsand atherosclerosis were mainly present in animal models, but few in humans.Determining the association between ACAT-1gene polymorphism and humanatherosclerosis related diseases help to understand the role of ACAT-1inatherosclerosis, and provide an important guiding value for drug development ofACAT inhibitors.Objective: The aim of the present paper was to explore the associationbetween the ACAT-1rs1044925Single Nucleotide Polymorphism (SNP) and serum lipid levels, and whether this SNP is associated with the susceptibility ofCoronary Heart Disease (CHD) and Ischemic Stroke (IS).Method: The genotypes of the ACAT-1rs1044925SNP were determined inall of the enrolled subjects by polymerase chain reaction-restriction fragmentlength polymorphism (PCR-RFLP). The epidemiological survey and serum lipidmeasures were carried out in all of the subjects. Depending on the differentresearch subjects, the study were divided into three stages: the first stage wascarried out in626Guangxi Bai Ku Yao subjects and624Guangxi Han subjects,the differences in serum lipid levels between the two populations, and thediffereces in genotypic and allelic frequencies between the two population weredetermined. Then the associations between ACAT-1rs1044925SNP and serumlipid levels were determined. The second stage was carried out in476hyperlipemia and345normal lipids subjects in Guangxi Han, the associationsbetween ACAT-1rs1044925SNP and serum lipid lipid were determined in thetwo groups. The third stage, the differeces in the genotypic and allelicfrequencies between the cases (CHD,587; IS,555) and588healthy controlswere determined, and then to estimate the risk of rs1044925SNP for the CHDand IS.Results:1. The levels of serum total cholesterol (TC), high-densitylipoprotein cholesterol (HDL-C), apolipoprotein (Apo) A1and ApoB weresignificant lower in Bai Ku Yao than in Han (P <0.01for all). The A and Callele frequency was79.0%and21.0%in Guangxi Bai Ku Yao, and87.3%and12.7%in Guangxi Han Chinese(P <0.001); respectively. The AA, AC and CCgenotype frequency was63.3%,31.5%and5.2%in Bai Ku Yao, and75.6%,23.2%and1.1%in Han (P <0.001); respectively. The TC, low-densitylipoprotein cholesterol (LDL-C) and ApoB levels in Bai Ku Yao but not in Han were different between the AA and AC/CC genotypes in females but not in males(P <0.05for all). The C allele carriers had lower serum TC, LDL-C and ApoBlevels than those without the C allele carriers. The correlations between theserum lipid levels and environmental factors were also different between the twopopulations.2. There was no significant difference in the genotypic and allelicfrequencies of ACAT-1rs1044925SNP between the normolipidemia andhyperlipidemia. The serum TC, HDL-C and Apo A1levels in hyperlipidemicsubjects were significantly different between the AA and AC/CC genotypes inmales but not in females (P <0.05-0.01), the C allele carriers had higher serumTC, HDL-C and ApoA1levels than the C allele noncarriers. The association ofAC/CC genotypes and increased serum HDL-C and ApoA1levels inhyperlipidemia was mainly present in the male subjects withhypercholesterolemia, but not in those with hypertriglyceridemia. There were nosignificant differences in serum lipid levels between the AA and AC/CCgenotypes in the normolipidemic subjects.3. In the case-control study, the genotypic and allelic frequenciesof rs1044925SNP were significantly different between the CHD patients andcontrols (P=0.015) and borderline different between the IS patients andcontrols (P=0.05). The AC/CC genotypes and C allele were associated with adecreased risk of CHD and IS (CHD: P=0.014for AC/CC vs. AA, P=0.022for C vs. A; IS: P=0.014for AC/CC vs. AA; P=0.017for C vs. A). TheAC/CC genotypes in the healthy controls, but not in CHD or IS patients, wereassociated with an increased serum HDL-C concentration.Conclusion: The serum lipid levels and the genotypic and allelicfrequencies distribution were significantly different between the Guangxi Bai Ku Yao and Han population. The rs1044925SNP is associated with serum lipidlevels in sex-specific and ethinic-specific manner. Which suggestting that thediffereces in the serum lipids levels between the two populations attributed tothe differeces in the genotypes of ACAT-1rs1044925SNP. In the males withhypercholesterolemia, ACAT-1rs1044925SNP AC/CC genotypes wereassociated with increased of serum HDL-C levels, suggesting that the ACAT-1rs1044925SNP might influence the cellular cholesterol efflux, and indirectlymodulate serum HDL-C concentrations in hypercholesterolemia. The ACAT-1gene rs1044925SNP AC/CC genotype was associated with decreased risk ofCHD and IS, which may attribute to the effects on serum lipid levels. Part ⅡASSOCIATION OF SCARB1RS5888SNP AND SERUM LIPIDLEVELS AND ISCHEMIC HEART ANDCEREBROVASCULAR DISEASESBackground: The scavenger receptor class B type1(SCARB1) wasdescribed as the first functionally active HDL receptor capable of facilitating theselective uptake of HDL-C, thus play an important role in reverse cholesteroltransport, it was also described associatied with serum lipid levels andatherosclerosis. CHD and IS were the leading causes of mortality and morbidityin the world, Both CHD and IS shared the common pathophysiologymechanisms: atherosclerosis. Dyslipidemia such as elevated serum levels of TC,triglyceride (TG), LDL-C, and apolipoprotein (Apo) B, or low levels ofhigh-density lipoprotein cholesterol (HDL-C) and ApoA1is one of the mostimportant modifiable risk factors for CHD and IS. The studies on theassociations between SCARB1SNP and serum lipid levels and atherosclerosiswere poor.Objective: The present study was undertaken to detect the associationsbetween rs5888SNP and serum lipid levels in Guangxi general populations, andthe risk of rs5888SNP for CHD and IS.Methods: The genotypes of the SCARB1rs5888SNP were determined inall of the enrolled subjects by PCR-RFLP. The epidemiological survey and theblood lipid measurement were carried out in all enrolled subjects. The study wasdivided into three stages: the first stage was carried out in598Guangxi Bai KuYao subjects and585Guangxi Han subjects, the differences in serum lipidlevels and the differeces in genotypic and allelic frequencies between the twopopulations were determined. Then the association between SCARB1rs5888and serum lipid levels was determined. The second stage was carried carried in801Guangxi Mulao subjects and807Guangxi Han subjects, the differences inserum lipid levels and genotypic and allelic frequencies between the twopopulations were determined. Then the association between SCARB1rs5888SNP and serum lipid levels was determined. The third stage, the differeces in thegenotypic and allelic frequencies between the cases (CHD,601; IS,533) and582healthy controls were determined. Then estimate the risks of rs1044925SNP for the CHD and IS.Results:1. The TC, HDL-C, LDL-C, Apo A1levels were lower butApoB level was higher in Bai Ku Yao than in Han (P <0.05-0.001). Thefrequencies of C and T alleles were78.3%and21.7%in Bai Ku Yao, and73.7%and26.3%in Han (P <0.01); The frequencies of CC, CT and TT genotypes were60.0%,36.6%and3.4%in Bai Ku Yao, and54.2%,39.0%and6.8%in Han (P <0.01). The subjects with TT genotype in both Bai Ku Yao and Han had lowerserum HDL-C and ApoA1levels than these subjects with CC/CT genotypes (P <0.05for all). Subgroup analyses showed that the subjects with TT genotype inBai Ku Yao had lower HDL-C and ApoA1levels in males than the subjects withCC/CT genotypes (P <0.05for all), and the T allele carriers had higher TC,LDL-C and ApoB levels in females than the T allele noncarriers (P <0.05forall). The participants with TT genotype in Han also had a lower tendency ofHDL-C and ApoA1levels in males than the participants with CC/CT genotype,but the difference did not reach statistically significant (P=0.063and P=0.086;respectively). Serum lipid parameters were also correlated with severalenvironmental factors，but these correlations were different between the twopopulations. 2. Serum Apo B level was higher in Mulao than in Han, the genotypicfrequency was also different between the two groups. Serum HDL-C levels inMulao were different among the genotypes, the subjects with TT genotype hadlower HDL-C levels than the subjects with CC/CT genotype in females (P <0.05). For the Han population, serum TG, HDL-C, ApoA1, ApoB levels and theratio of ApoA1to ApoB in males were different among the genotypes, the Tallele carriers had lower serum HDL-C, ApoA1levels and ApoA1/ApoB ratioand higher serum ApoB levels than the T allele noncarriers (P <0.05for all), thesubjects with TT genotype had higher serum TG levels than the subjects withCC/CT genotypes. Serum lipid parameters were also influenced bygenotype-environmental interactions in Han but not in Mulao populations.3. The genotypic frequencies of SCARB1rs5888SNP were differentbetween CHD patients and controls, the subjects with TT genotype had high riskof CHD (OR=1.76, P=0.038for TT vs. CC; and OR=1.75, P=0.036for TTvs. CC/CT). There was no significant association between genotypes and therisk of IS. Further analysis showed that the subjects with TT genotype in thetotal population had lower levels of HDL-C than the subjects with CC/CTgenotypes (P <0.05), the subjects with TT genotype in controls but not in CHDor IS patients had higher levels of serum LDL-C and ApoB than those with CCgenotype (P <0.05for each).Conclusion: the serum lipid levels and genotypic and allelic frequencieswere significant different between Guangxi Bai Ku Yao and Han, as well asGuangxi Mulao and Han. The SCARB1rs5888SNP was associatied with serumlipid levels, the differeces in serum lipid levels between groups may attributed tothe differeces in the distribution of rs5888SNP genotypes. The SCARB1rs5888SNP is associated with reduced serum HDL-C levels were present in three populations, while SCARB1rs5888SNP is associated with increased serum TC,LDL-C and ApoB in ethnic-specific and sex-specific manner. SCARB1rs5888SNP TT genotype is associated with increased risk of CHD, which mayattributed to the influences of the genotype on serum HDL-C. Part ⅢASSOCIATIONS BETWEEN MADD-FOLH1GENEPOLYMORPHISMS AND SERUM LIPID LEVELS ANDCORONARY HEART DISEASE AND ISCHEMIC STROKEBackground: Recent Genome Wide Association Study (GWAS) studieshave found some new genes that influence blood lipid levels. Compared with thetraditional lipid genes, these newly found genes had been considered nosignificant relationship with lipid metabolism, and its mechanism in lipidmetabolism is not known to human. MAP-kinase activating deathdomainprovided (MADD)-Folate hydrolase1(FOLH1) is a gene region that wasfound be associated with serum HDL-C levels, while the lipids andatherosclerosis are closely linked.Objective: The aim of the present study was performed to explore therelationships between several gene polymorphisms within the MADD-FOLH1area and serum lipid levels, and the gene-environmental interactions on serumlipid levels, to further explore its relationships with coronary heart disease (CHD)and ischemic stroke (IS).Methods: Take SNP reported in the literature combined with functionalSNP selection strategy, selected six SNPs including the rs7395662loci reportedin GWAS associated with lipids, as well as five in exons or promoter region ofrs326214, rs326217, rs1051006, rs3736101, rs7120118in MADD-FOLH1area,The genotypes of SNPs were detected using Snpshot genotyping technique, allof the subjects completed epidemiological investigation, blood lipid levels andother biochemical measures. The present research was carried out in three steps:the first step was carried out in the596normal controls, the difference in lipidlevels between the genotypes of the six SNPs were detected. The second step was carried out in the case group (CHD,584; and IS,555) and596healthycontrols, the differeces in the genotypic frequency between cases and controlsgroup were detected. Further estimates the risk of the genotypes for CHD and IS.The third step is the use the material of the first and second steps, factorialanalysis was used to determine if there are interactions between genes andsmoking, alcohol consumption and body mass index (BMI) on serum lipid levels,using logistic regression analysis to determine whether the interactions betweengenes and the environment factors influences the risk of the disease.Result:1. There were significant differeces in serum TG, HDL-C andApoA1levels between rs7395662genotypes, the subjects with GG genotypehad higher levels of TG than these with AA/AG genotypes, subjects with Gallele had lower serum HDL-C, ApoA1levels than thses without G allele. Thereare differences in serum HDL-C levels between the genotypes of rs326214SNP,the subjects with AA genotype had lower serum HDL-C levels. The remainingfour SNPs were not associated with lipid levels. There are significantassociations of rs7395662SNP and serum TG and HDL-C levels afterBonferroni correction.2. The genotypic and allelic frequencies of rs7395662SNP are significantdifferences between the control group and CHD group, and the control groupand IS. Genotypic and allelic frequencies of the remaining five sites were notsignificant different between the control group and the case groups. AfterBonferroni correction, the associations between the rs7395662genotypes andthe risk of CHD remains significant: Codominant Model: GG vs. AA (OR=0.78,95%CI:0.66-0.92, P=0.0068); Recessive model: the GG vs. AA/GA(OR=0.63,95%CI:0.46-0.86, P=0.0038); Log-additive model: G vs. A (OR=0.78,95%CI:0.66-0.92, P=0.003). After Bonferroni correction, the associations between the rs7395662genotypes and the risk of IS risk remainssignificant: Dominant Model: GA/GG vs. AA (OR=0.70,95%CI:0.55-0.89, P=0.0039); Log-additive model: G vs. A (OR=0.78,95%CI:0.66-0.91, P=0.0024). rs1051006, rs326214, rs326217, rs3736101, rs7120118was not foundassociated with the risk of CHD and IS, but there is linkage disequilibriumbetween them, these five loci haplotype analysis found: compared withhaplotype A-G-T-G-C, G-G-T-G-C had1.59times higher risk of coronary heartdisease (P=0.026), but the difference in the overall P value was not significant(P=0.099). In IS group, compared with A-G-T-G-C, G-A-T-G-C has1.95times the risk of ischemic stroke (P=0.039), but the difference in the overall Pvalue was not significant (P=0.13).3. Interactions between genotypes of the six SNPs and smoking, alcoholconsumption and BMI on blood lipids were detected, after Bonferroni correctionstill makes sense to have: rs7395662SNP interacted with alcohol on serum TGand HDL-C levels, stratified analysis shows the effect of genotype on TG levelswere present in nodrinkers, the subjects with GG genotype has a high TG levelsthan these with AA/AG genotypes. The influence of rs7395662genotype onserum HDL-C levels mainly present in the drinking group, the subjects with AAgenotypes have higher HDL-C levels than these with AG/GG genotypes. Thers7395662genotypes interacted with smoking on serum TG levels, subjects withGG genotype had higher TG levels than these with AA/AG genotypes mainlypresent in smokers.The genotypes of rs326214SNP and rs326217SNPinteracted with alcohol consumption on serum TG, the impact of genotype onserum TG mainly in drinkers, homozygous mutant had high serum TG levelscompared to wild-type homozygotes and heterozygotes. The rs3736101genotype interacted with smoking, alcohol consumption on serum HDL-C levels, the impact of genotype on serum HDL-C levels mainly in smokers or drinkers,compared with wild-type genotype carrying, the mutant had higher HDL-Clevels. The rs7120118interacted with alcohol consumption on serum TG levels,stratified analysis shows the associations of the genotypes and serum TG levelswere not found in drinkers or nodrinkers. The rs1051006SNP interacted withBMI on serum LDL-C, in subjects with BMI <24, no differences in serumLDL-C levels between genotypes, while in subjects with BMI≥24, subjectswith GG genotype had lower serum LDL-C levels than these with AA/AGgenotypes.4. The interaction between rs3736101SNP genotype and alcohol on CHDwas detected, individuals with GA/AA genotype have a higher risk of CHD thanindividuals with the GG genotype in nodrinkers, but this risk did not reachstatistical significance (OR=1.6895%CI:0.99-2.86). In the drinkers, thesubjects with GA/AA genotypes had reduced risk of CHD compared to subjectswith GG genotype (OR=0.33,95%CI:0.12-0.89). The remaining5SNP wasnot found interacted with the environment factors on CHD and IS.5. The interactions between haplotypes and drinking on the risk for CHDwere detected (P for interaction=0.00041), but the interactions betweenhaplotypes and drinking on the IS risk did not rearch statistical significance (P=0.061)Conclusion: FOLH1rs7395662SNP is associated with serum TG, HDL-Cand ApoA1levels, also associated with the risk of CHD and IS, the impact ofthis SNP on disease may not through by serum lipids. The remaining five SNPwas not significant associated with serum lipid levels, but haplotype analysismay show its haplotype was associated with IS and CHD. Genotypes interactedwith smoking, drinking and BMI on blood lipid levels, and the interaction between genotype and alcohol on lipid may also lead to changes in the risk ofdisease. Haplotype interacted with alcohol consumption have an impact on therisk of disease...