缺血性心脑血管病患者血浆同型半胱氨酸水平及其代谢相关酶基因多态性分析

目的　了解缺血性心脑血管病患者血浆同型半胱氨酸 (Hcy)水平的变化 ,分析该变化与Hcy代谢相关酶基因变异的相关性。方法　用高效液相色谱结合荧光检测法测定 80名正常人 ,86例脑梗死 ,6 6例心肌梗死患者血浆总同型半胱氨酸 (tHcy)浓度 ,分析血浆tHcy水平与缺血性心脑血管疾病与胱硫醚 β 合成酶 (CBS)基因 844ins6 8、甲硫氨酸合成酶 (MS)基因A2 75 6G、亚甲基四氢叶酸还原酶(MTHFR)基因C6 77T三种Hcy代谢相关酶基因突变之间的相关性。结果　缺血性心脑血管病患者血浆tHcy水平 [脑梗死组 (19.5 9± 10 .6 5 ) μmol/L ,心肌梗死组 (2 1.13± 9.5 7) μmol/L]较正常对照组[(13.73± 4.78) μmol/L]显著升高 (P <0 .0 5 ) ;MTHFRC6 77T纯合突变者血浆tHcy水平无论在正常对照组或患者组均较野生型及杂合突变者明显升高 (P <0 .0 5 )。MSA2 75 6G ,CBS 844ins6 8基因突变者血浆tHcy水平差异无显著性。结论　高Hcy血症是缺血性心脑血管病的重要危险因子 ,MTHFRC6 77T纯合突变可能是导致血浆Hcy水平轻、中度增高的遗传决定簇。     

Folate status and homocysteine level in Italian patients aged under 60 on oral anticoagulant therapy

BACKGROUND: Folate deficiency occurs frequently and the related hyper-homocysteinaemia is considered a risk factor for thrombosis. We investigated folate status and homocysteine (Hcy) concentration in patients under 60 years on oral anticoagulant therapy (OAT) for previous venous or arterial thrombosis and in healthy blood donors. PATIENTS AND METHOD: Thirty-nine patients (mean age 35.2 years) on OAT for longer than 6 months and forty 44 healthy blood donors (mean age 36.0 years) were evaluated. Diet, serum folate (SF), red blood cell folate (RCF), homocysteinaemia, vitamin B12 levels and the mutation C677T of methylenetetrahydrofolate-reductase (MTHFR) gene were determined. RESULTS: The mean SF and Hcy concentrations were significantly higher in patients compared with blood donors (SF = 17.7 versus 10.5 nmol/L, P < 0.0001; Hcy = 11.7 versus 8.9 micromol/L, P = 0.009). Twelve out of 39 patients and 7 out of 44 blood donors were homozygous for the mutation C677T of MTHFR gene. Among the remaining subjects, non-homozygous for the mutation, the patients (27) had mean SF and Hcy levels significantly higher than the (37) blood donors (SF = 18.1 versus 10.8 nmol/L, P < 0.0001; Hcy = 10.3 versus 7.9 micromol/L P < 0.0006). CONCLUSION: Italian patients aged under 60 years on OAT and non-homozygous for the mutation C677T of MTHFR gene, had SF and Hcy concentrations significantly higher than the control group.     

H型高血压患者MTHFR C677T基因多态性及其与血压、HCY水平的关系

目的探讨H型高血压患者亚甲基四氢叶酸还原酶(MTHFR)基因C677T位点碱基的分布特征及其与血压、同型半胱氨酸(HCY)水平的关系。方法检测2019年1-8月该院收治的135例H型高血压患者(观察组)的收缩压、舒张压、HCY水平和MTHFR基因C677T位点碱基分布特征,并与134例非H型高血压者(对照组)比较。结果观察组MTHFR基因C677T位点TT纯合子突变频率较对照组高(P<0.01),T等位频率较对照组高(P<0.01)。TT纯合子突变型收缩压和HCY水平较CC型高(P<0.01)。观察组CC、CT和TT型HCY水平高于对照组(P<0.05);在观察组中,TT型HCY水平高于CC型(P<0.05),也高于CT型(P<0.05);在对照组中,TT型HCY水平高于CC型(P<0.05),TT型HCY水平与CT型比较,差异无统计学意义(P>0.05)。结论H型高血压患者MTHFR基因C677T位点TT纯合子突变频率高,MTHFR基因C677T位点碱基突变对收缩压和HCY水平有影响,MTHFR基因C677T碱基突变型携带者HCY和总胆固醇水平升高。     

5,10-Methylenetetrahydrofolate reductase 677C-->T and 1298A-->C mutations are genetic determinants of elevated homocysteine

BACKGROUND: Methylenetetrahydrofolate reductase (MTHFR) is one of the main regulatory enzymes of homocysteine metabolism. Elevated plasma total homocysteine (tHcy) is a major risk for cardiovascular disease. A common 677C-->T mutation in the MTHFR gene results in decreased enzymic activity, and contributes to increased plasma tHcy, in association with low plasma folate. A recently described 1298A-->C mutation in the MTHFR gene clearly reduces MTHFR activity (although to a lesser extent than the 677C-->T) but its effect on plasma tHcy levels is not yet clear. AIM: To investigate the frequency of these two MTHFR polymorphisms in a Portuguese population, and to correlate the MTHFR genotype with the biochemical phenotype at the level of homocysteine and folate concentrations. DESIGN: Prospective population survey. METHODS: We studied 117 healthy volunteers (71 females, 46 males). The 677C-->T and 1298A-->C mutations were screened by PCR-RFLP. Levels of plasma tHcy and folate, and red blood cell folate, were determined. RESULTS: The allele frequencies of the 677C-->T and 1298A-->C mutations were 0.33 and 0.28, respectively. Homozygotes for the 677C-->T mutation had significantly elevated plasma tHcy and RBC folate levels and significantly lowered plasma folate concentrations than subjects without the mutation. The 1298A-->C mutation showed a significant effect on plasma tHcy, but not on plasma folate or RBC folate levels. DISCUSSION: The observed 677T allele frequency is not consistent with the idea of a north-south gradient as previously suggested. The 1298A-->C mutation is common in Portugal. Both MTHFR mutations showed effects on plasma tHcy levels.     

颈动脉粥样硬化超声表现与同型半胱氨酸及MTHFR基因多态性的相关性

目的 探讨颈动脉粥样硬化超声表现与血浆同型半胱氨酸(Hcy)及MTHFR C677T基因多态性之间的相关性。方法 143例颈动脉粥样硬化患者作为动脉硬化组,再进一步细分为内膜增厚亚组(75例)与斑块亚组(68例),选择91名无颈动脉内膜增厚及斑块形成者作为对照组。对所有研究对象均进行血浆Hcy及MTHFR C677T基因多态性检测。结果 MTHFR C677T基因CC、CT及TT型血浆Hcy水平依次逐渐升高,各组间差异有统计学意义(P<0.05)。血浆Hcy是颈动脉粥样硬化的独立危险因素(P<0.05),而MTHFR C677T基因多态性未进入回归方程。结论 血浆Hcy升高是颈动脉粥样硬化的独立危险因素;MTHFR C677T基因多态性在颈动脉粥样硬化与正常人群中分布不同,并与血浆Hcy水平相关,但不是颈动脉粥样硬化的独立危险因素。     

育龄女性MTHFR、MTRR基因多态性分布以及与血清叶酸和同型半胱氨酸水平的相关性研究

目的探讨叶酸代谢关键酶基因5,10-亚甲基四氢叶酸还原酶(MTHFR)C677T、A1298C和甲硫氨酸合成酶还原酶(MTRR)A66G多态性在育龄女性中的分布特征,并分析不同遗传特征对外周血叶酸和同型半胱氨酸(Hcy)水平的影响。方法选取2018年3月至2020年1月在上海计生所医院妇科就诊的汉族育龄女性2 651例,根据知情同意原则,采集口腔黏膜上皮脱落细胞,抽提基因组DNA,使用荧光定量PCR方法检测MTHFR C677T、A1298C和MTRR A66G基因多态性,采用化学发光法检测外周血叶酸水平,循环酶法检测血清Hcy水平。结果 (1)MTHFR C677TCC、CT、TT的基因型频率分别为33.2%、47.9%、18.9%,C、T等位基因频率分别为57.1%、42.9%;MTHFR A1298C AA、AC、CC的基因型频率分别为66.6%、30.5%、2.9%,A、C等位基因频率分别为81.8%、18.2%;MTRR A66G AA、AG、GG的基因型频率分别为56.4%、36.9%、6.8%,A、G等位基因频率分别为74.8%、25.2%。(2)MTHFR C677T和A1298C两位点连锁有7种组合,频率最高的是CT/AA(31.9%),没有CT/CC和TT/CC组合。两位点间存在完全连锁不平衡(D′=0.984,R2=0.161)。(3)MTHFR C677T不同基因型的叶酸和Hcy水平差异有统计学意义(P<0.05)。TT基因型的叶酸水平低于CC基因型,TT基因型的Hcy水平高于CC基因型。经单因素Logistic回归分析发现,MTHFR C677T TT基因型发生高Hcy血症的危险性是CC基因型的9.97倍(95%CI:3.81~26.05)。MTHFR A1298C和MTRR A66G不同基因型与血清叶酸及Hcy水平差异无统计学意义(P>0.05)。(4)经单因素回归分析,Hcy水平与叶酸水平呈负相关(R2=0.061,P<0.05),叶酸水平可解释Hcy水平个体差异的6.1%。结论获取了上海市汉族育龄女性MTHFR和MTRR基因多态性的群体遗传学特征,血清Hcy水平与MTHFR C677T基因多态性以及血清叶酸水平有关。筛查MTHFR和MTRR基因多态性并监测Hcy水平对围生期保健有重要的指导意义。     

MTHFR基因多态性和同型半胱氨酸在冠心病脑梗死和糖尿病中的分析

目的探讨冠心病、脑梗死、糖尿病患者亚甲基四氢叶酸还原酶（MTHFR）和血浆同型半胱氨酸（Hcy）的关系,对三个病种的MTHFR基因型进行分析。方法收集120例冠心病,214例脑梗死,112例糖尿病患者及98例健康体检者标本,采用聚合酶链式反应-限制性片段长度多态性（PCR-RFLP）技术检测MTHFRC677T基因,采用酶循环法检测血浆Hcy,比较四组MTHFRC677T基因多态性及血浆Hcy的差异。结果（1）MTHFR基因型在冠心病,脑梗死和糖尿病组与健康对照组间差异无统计学意义（P＝0．670）;（2）MTHFR基因频率在冠心病,脑梗死和糖尿病组与健康对照组间差异无统计学意义（P＝0．721）;（3）冠心病组和脑梗死组的MTHFR基因TT型患者的Hcy水平远远高于CC型和CT型患者（F＝6．212,P＝0．003;F＝44． 362,P＝0．000）。结论不同病种间MTHFR基因型和基因频率差异无统计学意义,但冠心病组和脑梗死组MTHFR基因TT型患者Hcy水平则远远高于CC型和CT型患者,差异有统计学意义。     

Methylenetetrahydrofolate reductase gene polymorphisms in Burkina Faso: impact on plasma fasting homocysteine and after methionine loading test

In Burkina Faso the levels of plasma homocysteine (Hcy) are lower and the methionine loading tests suggest a more effective Hcy metabolism. The polymorphisms of methylenetetrahydrofolate reductase (MTHFR) showed a relevant difference in the allele frequencies of T MTHFR-677 in young and in old subjects, while the allele frequency of C MTHFR-1298 was comparable in young and old subjects. The aim of this paper was to study the impact of the MTHFR polymorphisms on plasma fasting Hcy and after methionine loading in Burkina Faso. The young subjects with CC MTHFR-677 genotype had levels of Hcy significantly lower than CT and TT subjects. The level of Hcy in subjects who had AA, AC and CC MTHFR-1298 genotypes were comparable. The levels of Hcy after the methionine loading test were significantly higher in CT and TT MTHFR-677 genotype. These results suggest that the genetic situation in Burkina Faso is different from that of other Western countries and this guarantees the maintenance of lower plasma levels of Hcy in young and old Africans. The elevated levels of plasma Hcy in old subjects compared to young subjects, against the low prevalence of the T allele in elderly subjects, is discussed.     

妊娠高血压综合征患者MTHFR基因C677T多态性与Hcy及肾功能指标的相关性研究

目的探讨妊娠高血压综合征(简称妊高征)患者5,10-亚甲基四氢叶酸还原酶(MTHFR)基因C677T多态性与同型半胱氨酸(Hcy)、肾功能指标的相关性。方法纳入妊高征患者86例(疾病组,根据疾病严重程度,进一步分为妊娠高血压组、轻度子痫前期组、重度子痫前期组3个亚组),同时纳入健康妊娠女性200例(正常妊娠组)和健康非妊娠女性150例(健康对照组),采集研究对象的血液标本进行Hcy、尿酸(UA)、肌酐(Cr)及尿素氮(BUN)水平检测,并进行分析。此外,对86例妊高征患者的MTHFR基因进行测序,利用Chromas软件对测序结果跟健康人群进行比对,找出多态性位点进行分析。结果与健康对照组、正常妊娠组相比,疾病组Hcy、UA、Cr及BUN水平均明显升高(P<0.05),且以上指标在重度子痫前期组明显升高(P<0.05)。MTHFR C677T基因型与Hcy具有相关性(P<0.05),Hcy在TT基因型患者中的水平高于CC基因型和CT基因型患者(P<0.05)。结论Hcy及肾功能指标可作为妊高征辅助诊断及病情监测的重要指标,MTHFR基因C677T多态性的检测可为妊高征患者病情严重程度及预后判断提供一定依据,为发现妊高征高危人群提供新思路。     

急性淋巴细胞白血病患儿亚甲基四氢叶酸还原酶基因多态性与甲氨蝶呤动态血药浓度相关性的研究

目的本研究旨在探讨亚甲基四氢叶酸还原酶(MTHFR)C677T、A1298C基因多态性对急性淋巴细胞白血病(ALL)患儿使用大剂量甲氨蝶呤(HD-MTX)化疗期间的MTX动态血药浓度的相关关系。方法 35例ALL患儿外周血,提取基因DNA,应用PCR-RFLP方法检测MTHFR C677T、A1298C基因型;应用荧光偏振免疫分析法(FPIA)24h、48h、72h监测患儿外周血中甲氨蝶呤动态血药浓度。结果 MTHFR C677T各基因型间24 h MTX浓度有差异(P0.05),携带CT型者明显高于携带CC型和TT型者;MTHFR C677T各基因型48 h、72 h的MTX浓度未见差异。MTHFR A1298C各基因型24 h、48 h7、2 h的MTX浓度未见差异(P0.05)。结论 MTHFR C677T基因多态性影响ALL患儿HD-MTX化疗期间MTX血药浓度,提示在HD-MTX治疗时可根据检测MTHFR C677T基因型进行个体化治疗。     

C677T and A1298C polymorphisms of the methylenetetrahydrofolate reductase gene: incidence and effect of combined genotypes on plasma fasting and post-methionine load homocysteine in vascular disease

BACKGROUND: Moderately increased plasma concentrations of total homocysteine (tHcy) have been shown to be an important risk factor for vascular diseases. Two common polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene, the thermolabile C677T and a more recently reported A1298C polymorphism, may contribute to hyperhomocysteinemia. METHODS: Using PCR and restriction fragment length polymorphism analysis, we studied the prevalence of the C677T and A1298C MTHFR genotypes and the combined effect of these polymorphisms on plasma tHcy concentrations, as measured by HPLC with fluorometric detection, both fasting and post-methionine load (PML), in 1238 individuals. RESULTS: The prevalences of the C677T and A1298C genotypes did not differ significantly in 772 individuals with documented coronary artery disease (CAD), 137 individuals with deep-vein thrombosis (DVT), and 329 individuals without documented vascular disease. Individuals homozygous for the 677T allele had significantly increased fasting tHcy, particularly in the presence of low folate, compared with individuals homozygous for the wild-type allele. Neither the 1298AC nor the 1298CC genotype was associated with significantly increased fasting or PML tHcy concentrations irrespective of serum folate. Of the nine combined MTHFR genotypes, six were present in >10% of the population. Of these, the difference in mean fasting tHcy reached statistical significance (P<0.005) only in individuals with the 677TT/1298AA genotype compared with individuals with the wild-type 677CC/1298AA genotype. Differences in mean fasting tHcy did not reach statistical significance in individuals heterozygous for both MTHFR variants. We detected two 677CT/1298CC and three 677TT/1298AC individuals; only one, an 677TT/1298AC individual, had increased tHcy (both fasting and PML). No individuals had the 677TT/1298CC genotype. CONCLUSIONS: The prevalences of the C677T and A1298C polymorphisms did not differ among individuals with CAD, DVT, or those without documented vascular disease. In contrast to the C677T polymorphism, the A1298C polymorphism is not associated with increased fasting tHcy. Although the two polymorphisms usually exist in trans configuration, crossover may occur rarely to form recombinant chromosomes.     

The Relationship Between Homocysteine and Genes of Folate-Related Enzymes in Migraine Patients

(Headache 2010;50:99‐168) Background.— It has been suggested that homocysteine (Hcy) and the 5′‐10′‐methylenetetrahydrofolate reductase (MTHFR) C677T variant are implicated in the pathogenesis of migraine. Homocysteine has the potential to damage endothelium and accelerate atherosclerosis. Genetic factors such as the MTHFR C677T polymorphism, and other polymorphisms in folate‐related genes associated with high homocysteine levels, may contribute to increasing this vascular risk. Results.— We recruited 427 migraine patients (199 without aura [MO]; 228 with aura [MA]), and 310 controls in a neurologic clinic. Hcy levels and 6 polymorphisms corresponding to 6 folate‐related genes, including the MTHFR C677T variant, were determined in all migraine participants and in a subset of 155 controls. We found higher sex‐adjusted Hcy levels in MA (mean: 11.02 µM) than MO patients (9.86 µM; P = .005 for the difference). Hcy levels higher than 12.0 µM doubled the risk for MA (OR = 2.145; 95% confidence intervals [CI] = 1.3‐3.4; P = .001), and those higher than 15.0 µM incurred a 6‐fold increase (OR = 5.95; 95% CI = 2.1‐20.0, P < .001). The number of MTHFR 677T alleles was the best genetic predictor of Hcy levels (r² = 0.06; P = 6.2e‐6; corrected for genetic variants analyzed) and this effect remained significant after correction for other confounding factors. Using multi‐dimensionality reduction approaches, we observed significant epigenetic interaction among some of the folate‐related genetic variants to predict higher Hcy levels, and also among higher Hcy levels and folate‐related genetic variants to predict the end‐diagnosis of MA only among migraineurs. In controls, Hcy levels and the number of MTHFR 677T alleles were found to be intermediate between those observed in MA and MO patients. Conclusion.— Our results suggest that MA patients have higher Hcy levels. We also observed complex epigenetic interaction among folate‐related enzymes, sex, and Hcy levels predicting MA phenotype. Nevertheless, genetic factors explained only a minor proportion of the variance for both Hcy plasma levels and for predicting MA phenotype. Determination of MTHFR C677T polymorphisms and Hcy levels may be useful to identify patients with a high risk of suffering from MA.     

Folate status and homocysteine level in Italian patients aged under 60 on oral anticoagulant therapy

BACKGROUND. Folate deficiency occurs frequently and the related hyper-homocysteinaemia is considered a risk factor for thrombosis. We investigated folate status and homocysteine (Hcy) concentration in patients under 60 years on oral anticoagulant therapy (OAT) for previous venous or arterial thrombosis and in healthy blood donors. PATIENTS AND METHOD. Thirty-nine patients (mean age 35.2 years) on OAT for longer than 6 months and forty 44 healthy blood donors (mean age 36.0 years) were evaluated. Diet, serum folate (SF), red blood cell folate (RCF), homocysteinaemia, vitamin B12 levels and the mutation C677T of methylenetetrahydrofolate-reductase (MTHFR) gene were determined. RESULTS. The mean SF and Hcy concentrations were significantly higher in patients compared with blood donors (SF &#114 = &#114 17.7 versus 10.5 &#114 nmol/L, P &#114 < &#114 0.0001; Hcy &#114 = &#114 11.7 versus 8.9 &#114 &#55 mol/L, P &#114 = &#114 0.009). Twelve out of 39 patients and 7 out of 44 blood donors were homozygous for the mutation C677T of MTHFR gene. Among the remaining subjects, non-homozygous for the mutation, the patients (27) had mean SF and Hcy levels significantly higher than the (37) blood donors (SF &#114 = &#114 18.1 versus 10.8 &#114 nmol/L, P &#114 < &#114 0.0001; Hcy &#114 = &#114 10.3 versus 7.9 &#114 &#55 mol/L, P &#114 < &#114 0.0006). CONCLUSION. Italian patients aged under 60 years on OAT and non-homozygous for the mutation C677T of MTHFR gene, had SF and Hcy concentrations significantly higher than the control group.     

桂东南地区2型糖尿病肾病与 MTHFR 基因 C677T 多态性的相关性

目的：研究亚甲基四氢叶酸还原酶（MTHFR）基因多态性与2型糖尿病肾病（DN）的关系。方法应用聚合酶链反应-限制性片段长度多态性的方法,检测桂东南地区2型糖尿病患者163例 MTHFR 基因 C677T 多态性,其中 DN 82例、单纯糖尿病（DM）81例和健康对照组（CON）77例。同时检测血清同型半胱氨酸（Hcy）水平,并比较各组间 MTHFR 基因型频率、等位基因频率和 Hcy 水平。结果DN 组 MTHFR 基因纯合基因型（TT）、杂合基因型（CT）及 T 等位基因频率（分别为4．9％、37．8％和23．8％）均明显高于 DM 组（分别为2．5％、28．4％和16．7％）和 CON 组（分别为0．0％、29．8％和14．9％）,基因型和等位基因频率分布差异均有统计学意义（P ＜0．05）,而 DM 组和 CON 组之间的分布差异无统计学意义（P ＞0．05）。单因素 Logistic 回归分析结果显示,MTHFR 基因型 C677T 多态性与 DN 的发生密切相关（OR 值及其95％CI 分别为1．660、1．038和2．655）。携带T 等位基因患者血中 Hcy 水平显著高于未携带 T 等位基因患者,差异有统计学意义（P ＜0．01）。结论MTHFR 基因 C677T 多态性与桂东南地区2型糖尿病患者 DN 相关,MTHFR T 等位基因可能是该地区 DN 的易感基因。     

Factor V Leiden, pregnancy complications and adverse outcomes: the Hordaland Homocysteine Study

BACKGROUND: The factor V Leiden (FVL) mutation is the most common cause of inherited thrombophilia in Caucasian populations, and women with this variant allele are at increased risk for pregnancy complications. AIM: To examine whether the FVL allele is associated with pregnancy complications and adverse outcomes in a population-based study, and to identify potential factors that interact with the FVL genotype. DESIGN: Retrospective cohort study in a geographically-defined area. METHODS: Polymorphisms of factor V 1691G-->A, methylenetetrahydrofolate reductase (MTHFR) 677C --> T and 1298A --> C and plasma levels of total homocysteine, folate and vitamin B(12) were determined in blood samples collected in 1992-1993 from 5874 women aged 40-42 years, and linked with 14 474 pregnancies in the same women, recorded in the Medical Birth Registry of Norway, 1967-1996. RESULTS: The allelic frequency of FVL was 3.7% (6.9% heterozygotes, 0.3% homozygotes). Maternal FVL mutation was associated with significantly higher risks of pre-eclampsia (OR 1.63, 95%CI 1.15-2.30), pre-eclampsia at <37 weeks (OR 2.76, 1.34-5.70), low birth weight (OR 1.34, 95%CI 1.03-1.74) and stillbirth (OR 2.20, 95%CI 1.45-3.36). The presence of a variant allele for the 677C --> T MTHFR polymorphism strengthened the association between FVL and stillbirth (OR 3.34, 95%CI 1.95-5.73) (p(interaction) = 0.034). DISCUSSION: FVL mutation is a significant risk factor for pregnancy complications and adverse outcomes, and MTHFR 677CT/TT genotype can further enhance the risk of stillbirth.     

同型半胱氨酸及C677T基因多态性与妊娠期糖尿病关系分析

目的探讨同型半胱氨酸(Hcy)及亚甲基四氢叶酸还原酶(MTHFR)基因C677T位点多态性与妊娠期糖尿病(GDM)的相关性。方法以91例GDM孕妇为GDM组,123例正常妊娠孕妇为对照组,检测MTHFR C677T基因多态性及血清Hcy、血糖水平。结果 GDM组Hcy水平高于对照组,Hcy水平与空腹血糖水平呈正相关(P0.05)。GDM组与对照组MTHFR C677T多态性基因CC、CT、TT分布频率比较差异有统计学意义(P0.05)。GDM组TT型基因携带者Hcy水平高于CC型基因携带者(P0.05)。结论 Hcy与GDM的发生、发展密切相关。MTHFR C677T基因多态性可能通过影响Hcy水平而影响GDM的发生、发展。     

Erythrocyte membrane acetylcholinesterase activity in subjects with MTHFR 677C-->T genotype.

BACKGROUND: Increased homocysteine (Hcy) blood levels are correlated with vascular and neurological problems. AIM: The aim of the present study was to investigate erythrocyte membrane acetylcholinesterase (AChE) activity in subjects with the MTHFR C677T genotype in relation to Hcy. METHODS: Blood was obtained from 22 individuals with the MTHFR C677T genotype before and after folic acid supplementation and once from controls (n = 30). Plasma folate, vitamin B(12) and total antioxidant status (TAS) were measured with commercial kits, Hcy by a HPLC method and membrane enzyme activity spectrophotometrically. RESULTS: In MTHFR C677T carriers, AChE activity was significantly higher (4.20 +/- 0.12 x mg protein) and decreased to normal levels (3.14 +/- 0.10 x mg protein; p < 0.001) after therapy. TAS differed slightly before and after treatment. Hcy levels were significantly higher before (22.4 +/- 2.8 microM) compared to after (12.1 +/- 2.0 microM; p < 0.001) therapy and compared to controls (10.5 +/- 2.5 micromol/L; p < 0.001). In an in vitro study, incubation of Hcy-activated membrane AChE from controls with phenylalanine resulted in restoration of activity, but failed to reverse the stimulated enzyme from hyperhomocysteinaemic MTHFR C677T subjects before therapy. Alanine incubation protected the enzyme from Hcy activation in controls. CONCLUSIONS: Increased membrane AChE activity may be due to high Hcy levels. In vitro, phenylalanine reversed the Hcy activation of the membrane enzyme from controls and alanine protected it from Hcy action.     

Mutation of a 5,10-methylenetetrahydrofolate reductase gene in systemic lupus erythematosis and antiphospholipid syndrome

AIM: To study prevalence of mutation C677T in gene 5.10-MTHFR in systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) as well as in persons free of symptoms of systemic diseases of the connective tissue. MATERIAL AND METHODS: 85 patients participating in the study were divided into three groups: those with SLE (n = 17), with SLE + APS (n = 42), with primary APS (n = 26). The control group consisted of 30 persons without SLE or APS. 55% of the examinees had thrombotic complications of different location. The diagnosis of the mutation was made using DNA isolated from the peripheral blood with standard methods and polymerase chain reaction. Allele (homozygous or heterozygous) condition of the mutation was confirmed by means of allele-specific primers. RESULTS: Mutation C677T in MTHFR gene was found in 40 of 85 patients (47%); 11(27.5%) had a homozygous variant, 29(72.5%)--heterozygous. C677T mutation occurred in 5 of 17 SLE patients (29%), it was in all the cases heterozygous. In primary and secondary APS mutation was detected in 51.5% (35 of 68 patients). Recurrent thrombosis occurred more frequently in patients with mutation MTHFR. Three and more episodes of thrombosis were registered in 17 of 40 patients with mutation C677T against 9 of 44 patients without the mutations (p = 0.04). CONCLUSION: Relationship between elevated blood levels of APL and MTHFR mutation points to the fact that this genetic marker is an additional thrombogenic factor in APS. Mutation C677T in MTHFR gene in APS patients correlates with recurrent thrombosis.     

MTHFR基因型与晚期肾脏病/肾移植受者血浆高半胱氨酸水平及心血管病发生率的关系

目的 探讨血浆高半胱氨酸(Hcy)在肾脏病患者发生心血管疾患中的影响。方法 采用荧光偏振免疫分析、DNA基因型别分析等技术,对50例晚期肾脏病患者及肾移植受者进行了Hcy水平、N5,N10-亚甲基四氢叶酸还原酶(MTHFR)基因多态性分布测定及相关分析,并与肾病综合征患者及正常人进行对照。结果 (1)受检人群中Hcy水平较正常人及肾病综合征患者组明显升高;(2)受检人群中MTHFR的TT突变机率较正常人及肾病综合征组明显升高;(3)TT基因型与Hcy水平升高及心血管疾患的发生机率密切相关。结论 血浆中的Hcy可能是晚期肾脏病患者和肾移植受者体内的一种重要毒性物质。受检人群中MTHFR的高频率TT突变可能与血浆Hcy的水平升高有关。     

Predictors of vitamin B6 and folate concentrations in older persons: the InCHIANTI study

BACKGROUND: Low dietary intake and low serum concentrations of vitamin B6 and/or folate are associated with increased risk of vascular events, possibly because of their association with inflammation, which plays a crucial role in the pathogenesis of cardiovascular diseases. METHODS: Using data from 1320 participants in the population-based InCHIANTI study (586 men and 734 women; median age, 69 years; range, 21-102 years) for whom complete data on folate, vitamin B6, inflammatory markers, 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T sequence variant, and important covariates were available, we evaluated the association of inflammatory markers with circulating concentrations of vitamin B6 and folate, independently of dietary vitamin intake, circulating vitamin concentrations, and MTHFR C677T sequence variant. RESULTS: According to multiple linear regression analysis, C-reactive protein and interleukin-6 receptor were strongly and negatively associated with circulating vitamin B6 but not with folate concentrations, independent of age, sex, serum creatinine, serum albumin, total energy intake, smoking history, dietary nutrient intake, and circulating homocysteine and vitamin concentrations. Serum folate concentrations were related to MTHFR 677 TT genotype in persons with folate intake in the lowest tertile (< 221.2 microg/day). Vitamin C and retinol intakes were strongly and positively associated with serum folate concentrations independent of age, sex, serum creatinine, serum albumin, total energy intake, smoking history, homocysteine plasma concentrations, dietary nutrient intakes, serum vitamin B6 and vitamin B12 concentrations, and MTHFR C677T sequence variant. CONCLUSIONS: Low serum vitamin B6, but not serum folate, concentrations are independent correlates of the proinflammatory state, and both are influenced by antioxidant reserves.