脑血管病患者血浆同型半胱氨酸水平及MTHFR基因多态性分析

Analysis between Plasma Homocysteine Level and the Gene Polymorphism of MTHFR in Cerebrovascular Disease Patients

目的探讨血浆同型半胱氨酸(homocysteine Hcy)水平与脑血管病的关系及其水平升高的遗传和营养因素。方法对130例脑梗死和77例脑出血患者及65例正常对照者采用高效液相色谱(HPLC)法检测血浆Hcy水平、放射免疫法测定叶酸、VitB_(12)水平,运用多聚酶链反应-限制性内切酶片段长度多态性技术(PCR-RFLP)分析亚甲基四氢叶酸还原酶(methylenetetra-hydrofolate reductase MTHFR)基因多态性,并加以对照分析。结果脑梗死组、脑出血组血浆Hcy水平分别为19.87±11.67μmol/L、20.15±10.12 μmol/L.均显著高于对照组11.41±3.28 μmol/L(P<0.01);而脑梗死组与脑出血组间无显著差异(P>0.05)。MTHFR 有三种基因型,脑梗死组、脑出血组和对照组 C/C 型基因频率分别为0.39、0.46、0.53,C/T 型分别为0.35、0.31、0.30,T/T 型分别为0.26、0.23、0.17,T 等位基因频率分别为0.43、0.39、0.32,各基因型及等位基因频率无显著差异(P>0.05)。各组中 T/T 基因型血浆 Hcy 水平与 C/C 型比较差异有显著性(P<0.01),而病例组中C/T型血浆Hcy水平与C/C型相比亦有显著差异(P<0.01)。脑梗死组与脑出血组叶酸、VitB_(12)水平显著低于正常对照组(P<0.01)。结论血浆 Hcy 水平升高是脑血管病的主要危险因素。MTHFR基因677位点碱基 C→T突变可能是血浆Hcy水平升高的主要影响因素,但与脑血管病的直接关系有待进一步研究,而叶酸VitB_(12)与Hcy水平也有关联。

Objective To investigate the relationship between plasma homocysteine level and cerebrovascular disease as well as the genetic and nutritional factors of elevated plasma homocysteine(Hcy)level.Methods 130 patients with cerebral infarction,77 patients with cerebral bleeding and 65 healthy controls were analysed in the study. Their plasma total Hcy levels were measured by high-performance liquid chromatography(HPLC)method,the level of folate and VitB_(12)was measured using radioimmunoassay and methylenetetrahydrofolate reductase(MTHFR)geno- type was measured by polymerase chain reaction and restriction fragment length polymorphism(PCR-RFLP). Results The plasma Hcy level in cerebral infarction patients was 19.87±11.67μmol/L and in cerebral bleeding patients,20.15±10.12μmol/L;both were markedly higher than that of the controls 11.41±3.28μmol/L(P< 0.01);however,there were no significant difference between them(P>0.05).There were 3 kinds of genotypes. The frequencies of C/C genotype in cerebral infarction patients,cerebral bleeding patients and the controls were 0.39,0.46,0.53 respectively;C/T genotype was 0.35,0.31,0.30;T/T genotype was 0.26,0.23,0.17;frequen- cies of T allele were 0.43,0.39,0.32.Neither the genotype nor the allele frequency was markedly different between patients and control subjects.The plasma Hcy levels were the highest in each group with T/T genotype.Furthermore the Hcy level elevated could also be seen in two disease groups with C/T genotype.The folate and vitB_(12)levels of pa- tients were obviously lower than that of the control group.Conclusion The higher plasma Hcy level may be a main risk factor for cerebrovascular disease and is related to the CT mutation at locus 677 of MTHFR gene and folate level. However,further study of the direct relationship between MTHFR gene and cerebravascular disease should be made.