Association Of PDE4D And IL-1 Gene Polymorphism With Ischemic Stroke In A Han Chinese Population

Cerebrovascular disease(CVD) is one of the three major causes of death, and it is harmful to human health. Ischemic stroke(IS) accounts for about 70%of all CVD. IS is currently considered as a kind of complex disease influenced by the interaction of genetic and environmental factors, while genetic factors may play an important role in the pathogenesis. At present, the candidate genes of IS obtained by association analysis mainly include:①inflammation-related genes;②lipid metabolism genes;③renin angiotensin system-related genes;④nitric oxide synthase gene. However, these studies in different countries, regions or ethnic origin can get few good replication, suggesting that such research may have great regional differences. Therefore, it is necessary to verify those candidate genes in different populations.Atherosclerosis is the important pathophysiological basis IS. Now, it has been confirmed that the inflammatory reaction was of great importance in the process of atherosclerosis. Therefore, this study based on the Han population in northern China, a region having high incidence of IS, and selected Phosphodiesterase 4D(PDE4D) and Interleukin-1(IL-1), two important components of genes regulating the inflammatory system. In this candidate genes case-control analysis, we mesured genotype and allele frequencies of four PDE4D gene's SNPs (SNP83,SNP87,SNP219,SNP220) and two IL-1 gene's SNPs (IL-1A-889,IL-1B-511) between case and control group, and evaluated the association between these two genes'SNPs and IS. Therefore, we may provide more molecular epidemiology data for comprehensively understanding the potential genetic mechanisms and more early molecular biological diagnosis indicators of IS.Materials and methodsA case-control design was introduced. According to the different causes, the patients were divided into two subgroups:the large vessel group (thrombotic cerebral infarction group) and the small vessel group(lacunar infarction group).The subjects of large vessel group were consecutively recruited from the patients of northern China region patients with a total number of 371 cases, male 240, female 141, aged 41-74 years old, Han ethnic, no consanguinity with each other, the small vessel group were consecutively recruited from northern China region patients with a total number of 302 cases, male183,female 119, aged 41-76 years old, Han ethnic, no consanguinity with each other. The controls matched by age, sex, and ethnic orign were recruited from the same geographic region, with a total of 371, male 247, female 124. The SNPs of PDE4D SNP83,87 and IL-1A-889,IL-1B-511 were genotyped by the technique of polymerase chain reaction and restriction fragment length polymorphism(PCR-RFLP). PDE4D SNP219,220 were genotyped by means of Matrix-assisted laser desorption /ionization time-of-flight mass spectrometry primer extension (MALDI-TOF-PEX)reaction. Genotyping results were confirmed by dideoxy termination squencing method. SPSS 13.0 statistical software was used for data processing. Continuous variables were expressed as mean±SE and were assessed by One-Way ANOVA. Genotype and allele frequencies were calculated for control group and each of the patient groups. Univariate comparisons of allele and genotype distributions were analyzed by x2 test. The x2 goodness of fit test was used to test for deviation of genotype distribution from Hardy-Weinberg equilibrium. Conditional Logistic Regression was used for adjusting for IS traditional risk factors of IS. The influence of PDE4D and IL-1 gene polymorphisms on IS was indicated by odds ratio(OR) and 95% confidence interval(CI) with P<0.05 as significant criteria. Haplotype-based analysis was infered by using SHEsis online-software.Results1. The genotype frequencies of all SNPs conformed to the expectations of Hardy-Weinberg equilibrium(P>0.05). It was suggested that the selected samples could represent the population and were suitable for genetic analysis.2. PDE4D gene SNPs frequencies distributions among the large vessel and control group:SNP83CC genotype and C allele frequencies of the case group were higher than the control group(CC:P=0.001; OR= 1.788; 95%CI:1.280-2.497;C:P=0.003; OR= 1.368;95%CI:1.115-1.678); SNP219 AA genotyp and A allele frequencies of the large vessels group were higher than the control group(P=0.029; OR= 1.444; 95%CI: 1.037-2.010; A:P=0.048; OR= 1.228;95%CI:1.001-1.505), and after conditional logistic regression the differece was still significant(SNP83:OR= 1.479; 95%CI: 1.024-2.135; P=0.037; SNP219:P=0.046; OR=1.567; 95%CI:1.008-2.436).3. PDE4D gene SNPs'frequencies distributions among the small vessel and control group:Significant differences of all the frequencies were not observed between these two groups.4.PDE4D gene haplotypes'frequencies among the large vessel and control group: The frequencies of the haplotype built by SNP83 and SNP87 were normal among the patients and the controls; Among the haplotypes built by SNP219 and SNP220, AA's frequency of the case group was higher than the control group(P=0.013;OR=1.296; 95%CI:1.056-1.591), while the frequency of GA in the case group was lower than the control group(P=0.005; OR=0.650; 95%CI:0.482-0.878).5.PDE4D gene haplotypes'frequencies among the small vessel and control group: the frequencies of CT and TT in the control group were higher than those in the case group(CT:P=0.014;OR=0.637; 95%CI:0.444-0.913;TT:P=0.004; OR=0.662; 95%CI: 0.528-0.830),while the frequency of TC in the case group was higher than which in the control group(P=0.002;OR=1.861; 95%CI:1.391-2.490).6.IL-1SNPs'frequencies distributions among the cases and controls:the T allele's frequency of IL-1A-889 of the case group was higher than the control group (P=0.024; OR= 1.277;95%CI:1.033-1.577), and after conditional logistic regression the difference was still significant(P=0.034; OR=1.913; 95%CI:1.621-2.375). All the frequencies of genotypes and alleles of IL-1B-511 between the two groups had no significant differences.Conclusions1. PDE4D SNP83 might be associated with the risk of thrombotic cerebral infarction in northern han Chinese.2. The haplotypes built by PDE4D SNP83 and SNP87 might have no association With thrombotic cerebral infarction. The haplotype AA built by SNP219 and SNP220 might be at-risk haplotype of thrombotic cerebral infarction, meanwhile, GA might be be protective haplotype.3.The haplotype TC built by PDE4D SNP83 and SNP87 might be at-risk haplotype of lacunar infarction.4.The haplotype CT and TT built by PDE4D SNP83 and SNP87 might be protective haplotypes of lacunar infarction.5.PDE4D gene might be associated with the risk of lacunar infarction in northern han Chinese.6.Although t he result of our study supports the conclusion of deCODE, there still be some difference because of the difference of regions and ethnics.7. IL-1A-889 T allele might be associated with thrombotic cerebral infarction in northern han Chinese, but it need to be tested by larger studies.8. IL-1B-511 might have no association with IS in northern han Chinese.9. The association between IL-1 polymorphism and IS might be affected by the difference of regions,ethnics and nationalities.