影响亚甲基四氢叶酸还原酶和甲硫氨酸合成酶还原酶基因多态性的因素分析

目的了解影响女性亚甲基四氢叶酸还原酶(MTHFR)C677T、A1298C位点和甲硫氨酸合成酶还原酶(MTRR)A66G位点基因多态性的因素。方法采用横断面调查研究方法,以湖北省内1 902例女性为对象,采集口腔黏膜上皮细胞,提取DNA,用实时荧光定量PCR技术检测MTHFR和MTRR基因,统计分析不同民族MTHFR和MTRR基因多态性的差异,与其他地区人群的MTHFR和MTRR基因多态性进行比较,并分析不同位点基因多态性之间的关联关系。结果 (1)湖北省汉族女性和少数民族女性在MTHFR C677T和MTRR基因多态性构成差异无统计学意义(P>0.05),而MTHFR A1298C位点基因多态性构成差异有统计学意义(P<0.05)。(2)MTHFR C677T位点的纯合突变基因型TT的频率从南到北呈上升趋势,MTHFR A1298C位点的纯合突变基因型CC的频率从南到北呈下降趋势,而MTRR A66G位点基因多态性在不同地区差异不大。(3)MTHFR C677T位点的纯合突变基因型TT的频率在A1298C位点的正常型、杂合型、纯合突变型中分别为15.9%、0.1%、0.0%,差异有统计学意义(P<0.01);MTHFR C677T位点的纯合突变基因型TT的频率在MTRR A66G位点的正常型、杂合型、纯合突变型中分别为9.4%、5.9%、0.7%,差异无统计学意义(P>0.05)。结论 MTHFR A1298C位点基因多态分布存在民族差异;而MTRR C677T、A1298C位点基因多态分布存在地区差异;同一基因不同位点的基因多态性有关联。     

亚甲基四氢叶酸还原酶基因多态性两种检测方法之比较

目的应用实时荧光PCR技术，建立一种快速、准确的检测亚甲基四氢叶酸还原酶（MTHFR（677C→T））基因多态性的方法。方法采用实时荧光PCR技术和聚合酶链反应-限制性片段长度多态性（PCR—RFLP）同时检测300例健康体检者MTHFR（677C→T）位点的基因多态性，并以测序佐证检测结果的准确性。结果用2种方法均检出CC、CT、TT3种基因型，基因型频率和等位基因频率2组间差异无统计学意义（基因型P〉0．05，等位基因P〉0．05）。结论实时荧光PCR法准确、快捷，适合临床对该基因位点的快速分型。     

Homocysteine, vitamin B12 and folate in vascular dementia and in Alzheimer disease.

The association between elevated plasma levels of homocysteine (Hcy) and nutritional status has been shown in Alzheimer disease (AD) patients and also in vascular dementia (VaD). Moreover, a previous study provided evidence that the relation between a high Hcy level and low vitamin B12 and folate levels in AD patients is due to biochemical damage, rather than a nutritional deficit. The purpose of this study was to investigate the relationship between plasma Hcy levels and vitamins involved in its metabolism in AD and VaD. Twenty-two VaD patients, 22 AD patients and 24 healthy subjects were studied for Hcy, vitamin B12, vitamin B6 and folate. All patients and control subjects were comparable for age, educational level, nutritional and socioeconomic status. None of them showed macrocytic anemia or impaired renal function. Hcy was significantly increased in VaD patients (26.0 +/- 6.58 micromol/l) as compared to controls (10.7 +/- 3.0 micromol/l) and AD patients (22.3 +/- 4.51 micromol/l; p<0.001); however, AD patients also showed increased levels of Hcy. Folates were significantly reduced in both VaD (10.8 +/- 2.81 nmol/l) and AD (10.0 +/- 2.72 nmol/l; p<0.001) patients, while vitamin B12 showed significantly reduced levels only in AD patients (392.1 +/- 65.32 pmol/l; p=0.02). Vitamin B6 was not significantly different in the three groups. Increased levels of Hcy associated with low vitamin B12 plasma levels were found only in AD patients. This observation led us to consider that vitamin B12 metabolism does not represent the direct consequence of the nutritional status and suggests that neuronal damage results in a functional vitamin B12 deficiency, as emphasized by recent reports. New therapeutic strategies are necessary, considering that available pharmaceutical forms of vitamin B12 are not utilized by neurons in oxidative stress conditions.     

适龄期孕妇复发性流产与亚甲基四氢叶酸还原酶、纤溶酶原激活物抑制物1基因多态性及血清叶酸浓度关系的研究

目的:探讨适龄期妇女复发性流产（recurrent spontaneous abortion, RSA）与叶酸代谢基因亚甲基四氢叶酸还原酶（methylene Tetrahydrofolate Reductase, MTHFR）、纤溶酶原激活物抑制物1（plasminogen activator inhibitor-1...     

The common 'thermolabile' variant of methylene tetrahydrofolate reductase is a major determinant of mild hyperhomocysteinaemia

Mild hyperhomocysteinaemia is a major risk factor for vascular disease and neural tube defects (NTDs), conferring an approximately three-fold relative risk for each condition. It has several possible causes: heterozygosity for rare loss of function mutations in the genes for 5,10-methylene tetrahydrofolate reductase (MTHFR) or cystathionine-&bgr;-synthase (CBS); dietary insufficiency of vitamin co-factors B6, B12 or folates; or homozygosity for a common 'thermolabile' mutation in the MTHFR gene which has also been associated with vascular disease and NTDs. We quantified the contribution of the thermolabile mutation to the hyperhomocysteinaemic phenotype in a working male population (625 individuals). Serum folate and vitamin B12 concentrations were also measured and their relationship with homocysteine status and MTHFR genotype assessed. The homozygous thermolabile genotype occurred in 48.4, 35.5, and 23.4% for the top 5, 10 and 20% of individuals repectively) ranked by plasma homocysteine levels, compared with a frequency of 11.5% in the study population as a whole establishing that the mutation is a major determinant of homocystein levels at the upper end of the range. Serum folate concentrations also varied with genotype, being lowest in thermolabile homozygotes. The MTHFR thermolabile genotype should be considered when population studies are designed to determine the effective homocysteine-lowering dose of dietary folate supplements, and when prophylactic doses of folate are recommended for individuals.      

青年缺血性脑血管疾病独立危险因子与N5及N10-亚甲基四氢叶酸还原酶基因突变的关系

背景:血浆同型半胱氨酸浓度升高是动脉粥样硬化性血栓性脑梗死的独立危险因素,同型半胱氨酸在转硫化和再甲基化过程中的代谢酶N5,N10-亚甲基四氢叶酸还原酶(methylenetetrahydrofolatereductase,MTHFR)基因突变可致血浆同型半胱氨酸浓度升高。目的:探讨同型半胱氨酸血症、同型半胱氨酸代谢关键酶MTHFR基因突变与青年缺血性脑血管疾病的关系。设计:病例-对照观察。单位:吉林大学中日联谊医院神经内科。对象:于2003-04/2004-12吉林大学中日联谊医院神经内科收治发病2d内住院的青年脑梗死患者100例,为病例组,男73例,女27例;年龄27～45岁,平均(42±5)岁。对照组100例为同期健康体检者,男70例,女30例;年龄18～45岁,平均(39±4)岁。方法:以高效液相色谱法测定受试者空腹血浆同型半胱氨酸,采用聚合酶链反应-限制性内切酶片段长度多态性分析和扩增阻滞突变体系法,对MTHFR基因C677T位点和A1298C位点进行检测。主要观察指标:MTHFRC677T和A1298C基因检测,血浆同型半胱氨酸浓度与MTHFR基因型的关系。结果:纳入患者100例和正常对照100例,均进入结果分析。①MTHFRC677T和A1298C基因检测:MTHFRC677T基因检测病例组和对照组基因型分布、纯合子频率和等位基因频率差异均显著(P<0.01)。而MTHFRA1298C基因检测病例组和对照组基因型分布、纯合子频率和等位基因频率差异均无显著性(P>0.05)。②血浆同型半胱氨酸浓度与MTHFR基因型的关系:MTHFRC677T和A1298C各基因型间血浆同型半胱氨酸浓度差异有显著性(P<0.001)。2个位点突变结果LSD-t检验显示纯合子与杂合子,纯合子与野生型血浆同型半胱氨酸浓度均数差有统计学意义(P<0.05)。MTHFRC677T和A1298C杂合子与野生型血浆同型半胱氨酸浓度均数差无统计学意义(P>0.05)。结论:MTHFRC677T和A1298C突变均导致血浆同型半胱氨酸浓度明显增高。MTHFRC677T多态性位点是青年缺血性脑血管疾病的独立危险因子。MTHFRA1298C基因突变与青年缺血性脑血管疾病发病无相关性。     

青年缺血性脑血管疾病独立危险因子与N5及N10-亚甲基四氢叶酸还原酶基因突变的关系

背景：血浆同型半胱氨酸浓度升高是动脉粥样硬化性血栓性脑梗死的独立危险因素，同型半胱氨酸在转硫化和再甲基化过程中的代谢酶Ns，N10-亚甲基四氢叶酸还原酶（methylene tetrahydrofolate reduetase，MTHFR）基因突变可致血浆同型半胱氨酸浓度升高。 目的：探讨同型半胱氨酸血症、同型半胱氨酸代谢关键酶MTHFR基因突变与青年缺血性脑血管疾病的关系。 设计：病例-对照观察。 单位：吉林大学中丑联谊医院神经内科。 对象：于2003-04／2004-12吉林大学中丑联谊医院神经内科收治发病2d内住院的青年脑梗死患者100例，为病例组，男73例，女27例；年龄27-45岁，平均（42&;#177;5）岁。对照组100例为同期健康体检者：男70例，女30例；年龄18～45岁，平均（39&;#177;4）岁。 方法：以高效液相色谱法测定受试者空腹血浆同型半胱氨酸，采用聚合酶链反应-限制性内切酶片段长度多态性分析和扩增阻滞突变体系法，对MTHFR基因C677T位点和A1298C位点进行检测。 主要观察指标：MTHFRC677T和A1298C基因检测，血浆同型半胱氨酸浓度与MTHFR基因型的关系。 结果：纳入患者100例和正常对照100例，均进入结果分析。④MTHFRC677T和A1298C基因检测：MTHFR C677T基因检测病例组和对照组基因型分布、纯合子频率和等位基因频率差异均显著（P〈0．01）。而MTHFR A1298C基因检测病例组和对照组基因型分布、纯合子频率和等位基因频率差异均无显著性（P〉0．05）。②血浆同型半胱氨酸浓度与MTHFR基因型的关系：MTHFR C677T和A1298C各基因型问血浆同型半胱氨酸浓度差异有显著性（P〈0．001）。2个位点突变结果LSD-t检验显示纯合子与杂合子，纯合子与野生型血浆同型半胱氨酸浓度均数差有统计学意义（P〈0．05）。MTHFR C677T和A1298C杂合子与野生型血浆同型半胱氨酸浓度均数差无统计学意义（P〉0．05）。 结论：MTHFR C677T和A1298C突变均导致血浆同型半胱氨酸浓度明显增高。MTHFR C677T多态性位点是青年缺血性脑血管疾病的独立危险因子。MTHFR A1298C基因突变与青年缺血性脑血管疾病发病无相关性。     

亚甲基四氢叶酸还原酶基因多态性及血浆同型半胱氨酸水平与脑血管病的关系

目的探讨亚甲基四氢叶酸还原酶(MTHFR)基因多态性及同型半胱氨酸(Hcy)水平与脑血管病的关系.方法应用聚合酶链反应-限制性片断长度多态性(PCR-RFLP)技术分析223例脑血管病患者及100名正常对照者的MTHFR基因多态性,同时应用高效液相色谱法(HPLC)测定其血浆Hcy水平.结果 MTHFR基因677位T等位基因携带频率脑血管病组(48.9%)显著高于正常对照组(30.5%,P<0.05),在脑出血患者组(53.3%)与脑梗死患者组(47.2%)之间差异无显著性(P>0.05);脑血管病组血浆Hcy水平[(20.01±8.89) μmol/L]显著高于对照组[(9.12±3.19) μmol/L,P<0.05],而脑出血患者组[(21.71±7.72) μmol/L]与脑梗死患者组[(19.35±8.51) μmol/L]间差异无显著性(P>0.05);各组中MTHFR TT型、TC型血浆Hcy浓度明显高于CC型.结论 MTHFR C677T突变可引起血浆Hcy水平升高,从而增加患脑血管病的危险度.     

亚甲基四氢叶酸还原酶基因多态性及血浆同型半胱氨酸水平与脑血管病的关系

目的探讨亚甲基四氢叶酸还原酶(MTHFR)基因多态性及同型半胱氨酸(Hcy)水平与脑血管病的关系。方法应用聚合酶链反应-限制性片断长度多态性(PCR-RFLP)技术分析223例脑血管病患者及100名正常对照者的MTHFR基因多态性,同时应用高效液相色谱法(HPLC)测定其血浆Hcy水平。结果MTHFR基因677位T等位基因携带频率脑血管病组(48.9%)显著高于正常对照组(30.5%,P<0.05),在脑出血患者组(53.3%)与脑梗死患者组(47.2%)之间差异无显著性(P>0.05);脑血管病组血浆Hcy水平[(20.01±8.89)μmol/L]显著高于对照组[(9.12±3.19)μmol/L,P<0.05],而脑出血患者组[(21.71±7.72)μmol/L]与脑梗死患者组[(19.35±8.51)μmol/L]间差异无显著性(P>0.05);各组中MTHFR TT型、TC型血浆Hcy浓度明显高于CC型。结论MTHFR C677T突变可引起血浆Hcy水平升高,从而增加患脑血管病的危险度。     

RANTES promoter genotype is associated with diabetic nephropathy in type 2 diabetic subjects

OBJECTIVE: To evaluate the effect of RANTES gene promoter polymorphism and RANTES receptor (CCR5 gene) promoter polymorphism on diabetic nephropathy in Japanese type 2 diabetic subjects. RESEARCH DESIGN AND METHODS: A total 616 Japanese subjects with type 2 diabetes were recruited. Polymorphisms of -28 C/G and -403 G/A in the RANTES gene promoter region, and of 59029 G/A in the CCR5 gene promoter region were detected by PCR-RFLP (restriction fragment length polymorphism). The association of these genotypes with nephropathy was analyzed. RESULTS: While the RANTES -403 genotype showed no association with nephropathy, the frequency of the -28G allele was significantly higher in the DN2 group (urinary albuminuria-to-creatinine ratio [ACR] >or=300 mg/g creatinine, serum creatinine <2.0 mg/dl) than in the DN0 (ACR <30 mg/g creatinine) and DN1 (ACR >or=30 mg/g creatinine and <300 mg/g creatinine) groups. The frequency of a RANTES -28G-positive genotype (C/G or G/G) was higher in the DN2 group than in the DN0 and DN1 groups (34% vs. 25 and 20%, P = 0.0268, chi(2) = 4.905), and the frequency of a CCR5 59029 A-positive genotype (G/A or A/A) was higher in the DN1 and DN2 groups than in the DN0 group (84 and 85% vs. 76%, P = 0.0123, chi(2) = 6.269). Discriminant analysis showed that the RANTES -28G-positive genotype and CCR5 59029A-positive genotype were independently associated with nephropathy. The percentage of macroalbuminuria was twofold higher in the subjects having -28G or 59029A and threefold higher in the subjects having -28G and 59029A than in the subjects without -28G and 59029A. CONCLUSIONS: The RANTES promoter -28G genotype and CCR5 promoter 59029A genotype may be independent risk factors for diabetic nephropathy in patients with type 2 diabetes and may have an additive effect on nephropathy.     

Prospective analysis of mortality,morbidity, and risk factors in elderly diabetic subjects: Nagano study

OBJECTIVE: To clarify mortality and morbidity of intensively managed elderly diabetic individuals and to explore factors predicting mortality and diabetes-related end points. RESEARCH DESIGN AND METHODS: A total of 390 elderly (>or=65 years of age) outpatients with type 2 diabetes ( 173 men and 217 women, mean age 73.0 years) were analyzed. The mean HbA(1c) upon entry was 6.8% (332 receiving oral hypoglycemics and/or insulin) and blood pressure upon entry was 136/74 mmHg (219 receiving antihypertensive drugs). The patients have been followed-up for 3 years with HbA(1c) <7.0% and blood pressure <145/80 mmHg as targets, with mortality and an aggregate of fatal and nonfatal diabetes-related events as end points. Mortality rate and causes of mortality, as well as risk factors for mortality and morbidity, were determined. RESULTS: The mortality rate, 2.9% per year, was comparable to that of the age- and sex-matched general population. Stroke was a leading cause of mortality after malignancy. By the univariate Cox proportional hazards model, only high serum creatinine and prior stroke were highly significant and strong risks for both end points. In those without prior stroke and receiving antihypertensive agents, the incidence of the diabetes-related end point based on their systolic blood pressure (SBP) quartile was U-shaped, with the nadir at the 3rd (SBP, 137-147 mmHg) and the peak at the 1st (SBP 相似文献   

Homocysteine and diabetic macroangiopathy

Moderate hyperhomocysteinemia is one of risk factors for arteriosclerotic disease. In diabetic patients, hyperhomocysteinemia is an independent risk factor for macroangiopathy and mortality. Homocysteinemia is also associated with diabetic microangiopathy, silent stroke, and cognitive impairment. However, excluding those with nephropathy or microangiopathy, plasma homocysteine is lower in diabetic patients than non-diabetic controls. Oral treatment with folic acid, vitamin B12 and B6 reduces plasma homocysteine concentration about by 30%. The vitamin treatment for reduction of hyperhomocysteinemia improves endothelial dysfunction and retards carotid atherosclerosis. Few randomized control trials have showed a positive effect of the vitamin treatment on prevention from stroke and ischemic heart disease. Further prospective intervention studies are necessary to address the issue whether lowering homocysteine does prevent the development and progression of diabetic macroangiopathy.     

Opposite impact of Methylene tetrahydrofolate reductase C677T and Methylene tetrahydrofolate reductase A1298C gene polymorphisms on systemic inflammation

Background

Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms have been found to be related with many diseases. Systemic inflammation is now considered as a major predisposition factor for diseases including diabetes mellitus (DM), coronary arterial disease (CAD), stroke, and cancer. This study aimed to investigate whether systemic inflammation is a possible underlying pathogenesis for MTHFR gene polymorphism‐related disease.

Methods

A total of 292 patients were enrolled, and single nucleotide polymorphisms for MTHFR C667T and A1298C were genotyped. Systemic inflammation markers, neutrophil‐to‐lymphocyte ratio (NLR), and platelet‐to‐lymphocyte ratio (PLR) were collected.

Results

In our study population, MTHFR 677 variants had significant higher NLR level than MTHFR 677 wild type (3.77 ± 0.26 vs 3.06 ± 0.18, P = .028). Logistic regression analysis showed that MTHFR 677 variants were significantly associated with increased NLR level. MTHFR 1298 variants showed the opposite effects which tended to have lower level of NLR (3.21 ± 0.16 vs 3.79 ± 0.34, P = .087) and PLR (137.0 ± 4.8 vs 157.7 ± 9.4, P = .052) than MTHFR 1298 wild type. General linear model showed that there was no statistically significant interaction between MTHFR C667T and A1298C gene polymorphism on NLR or PLR.

Conclusions

This study indicates that MTHFR C677T and MTHFR A1298C gene polymorphisms have opposite effect on systemic inflammation, and systemic inflammation may contribute to the pathogenesis for diseases associated with MTHFR C667T gene polymorphism.

     

新疆维汉民族亚甲基四氢叶酸还原酶基因多态性及血浆同型半胱氨酸与冠状动脉粥样硬化性心脏病的关系

目的:分析新疆维汉民族亚甲基四氢叶酸还原酶基因C677T多态性及其与同型半胱氨酸水平、冠状动脉粥样硬化性心脏病之间的关系,以期为冠心病的预防和优化康复治疗提供理论依据。方法:收集2004-09/2005-10在新疆医科大学第一附属医院心内科住院并行冠状动脉造影术的320例维汉民族患者,按冠状动脉造影结果分为冠状动脉粥样硬化性心脏病组(n=189)与对照组(n=131),应用聚合酶链反应-限制性内切酶长度多态性方法检测亚甲基四氢叶酸还原酶基因C677T多态性,用荧光偏振免疫分析法测定血浆同型半胱氨酸水平,并分析同型半胱氨酸及亚甲基四氢叶酸还原酶基因C677T多态性与冠心病的关联性。结果:320例全部进入结果分析。①维汉民族冠状动脉粥样硬化性心脏病组和对照组亚甲基四氢叶酸还原酶C677TCC、CT、TT3种基因型分布(维吾尔族,χ2=9.561,P=0.008;汉族,χ2=10.618,P=0.005)和等位基因频率分布(维吾尔族,χ2=4.857,P=0.028;汉族,χ2=5.158,P=0.023)差异有统计学意义;但冠状动脉粥样硬化性心脏病组和对照组内维汉不同民族基因型分布和等位基因频率分布差异无统计学意义(P>0.05)。②维汉民族冠状动脉粥样硬化性心脏病组和对照组中,亚甲基四氢叶酸还原酶C677T各基因型之间血浆同型半胱氨酸水平的差异均有统计学意义(P<0.05)。其中TT基因型的血浆同型半胱氨酸水平均高于同组同民族CT和CC型者;CT基因型与CC基因型之间血浆同型半胱氨酸水平的差异无统计学意义P>0.05)。③经多因素非条件Logistic回归分析显示,亚甲基四氢叶酸还原酶C677T基因突变(OR=1.478)、同型半胱氨酸(OR=1.057)等因素是冠状动脉粥样硬化性心脏病的危险因素。结论:①同型半胱氨酸代谢关键酶基因亚甲基四氢叶酸还原酶C677T存在多态性,无民族差异。②亚甲基四氢叶酸还原酶C677T可导致血浆同型半胱氨酸明显增高。③亚甲基四氢叶酸还原酶C677T多态性和同型半胱氨酸是新疆维汉民族冠状动脉粥样硬化性心脏病发病的独立危险因素。     

Homocysteine, vascular dementia and Alzheimer's disease.

There is some evidence from recent observational studies that hyperhomocysteinemia is a risk factor for cognitive dysfunction, including Alzheimer's disease and vascular dementia. There are only a few intervention studies, and the results are disappointing for such a frequent disease. Prospective double-blind and placebo-controlled intervention studies are not available. If homocysteine-lowering therapy will be in the running for the prevention and treatment of dementia, we must be able to diagnose the disease at a preclinical stage (i.e. 5 or 10 or 20 years before the disease becomes clinically overt for Alzheimer's disease). At the moment, there are insufficient data to support a vitamin B12, B6 or folate therapy in the prevention or treatment of patients with dementia.     

Homocysteine, vitamin B 12 and folate in Alzheimer's and vascular dementias: the paradoxical effect of the superimposed type II diabetes mellitus condition

BACKGROUND: Increased concentration of plasmatic homocysteine (tHcy) and decreased vitamin B 12 (B12) and folate (FOL) are associated with Alzheimer's (AD) and vascular (VaD) dementias, with type II diabetes mellitus (DM), and reported as risk factors of these diseases. METHODS: The sample (n=122; males=60; mean age=73+/-7 years) comprised AD and VaD patients without DM, with a concomitant DM (AD+DM, VaD+DM), DM alone and controls (CTR), resulting in 6 groups. tHcy, B12 and FOL were determined in duplicate. RESULTS: The one-way ANOVA yielded significant differences between groups for all variables: tHcy p<10(-12); B12 p<10(-3); FOL p<10(-4). Significance for comparisons between groups was set at alpha=0.05, using the Bonferroni's statistic. The comparisons: DM vs. CTR, AD+DM vs. AD, VaD+DM vs. VaD, and DM demented vs. DM non-demented resulted significant for all variables, except for B12 in 2 comparisons. CONCLUSIONS: In demented and control subjects, tHcy and FOL exhibit extreme differences, not so marked between DM and controls. Demented patients with concomitant diabetes are closer to controls than their non-diabetic counterparts. Diabetes affects tHcy and FOL values, which are changed with opposite sign to non-demented. These results suggests a paradoxical phenomenon when diabetes is superimposed to dementias.