Genetic variation in fibrinogen; its relationship to fibrinogen levels and the risk of myocardial infarction and ischemic stroke

Summary.  Background: Confounding by common causes and reverse causation have been proposed as explanations for the association between high fibrinogen levels and cardiovascular disease. Genetic variants can alter fibrinogen characteristics and are not subject to these problems. Objectives: To determine the fibrinogen plasma levels for genotypic variants in fibrinogen-Aα (FGA Thr312Ala) and fibrinogen-Bβ (FGB − 455G/A), and whether these variants are associated with arterial thrombosis. Methods: Fibrinogen genotypes were determined in a population-based case–control study including women aged 18–50 years; 218 cases with myocardial infarction, 192 cases with ischemic stroke, and 769 healthy controls. Fibrinogen levels were determined in the control population. Results: The FGB − 455G/A variant increased plasma fibrinogen levels, whereas the FGA Thr312Ala variant lowered plasma fibrinogen levels, albeit to a modest extent. The risk of ischemic stroke was altered when the homozygote minor allele was compared with the homozygote major allele. The FGA Thr312Ala single-nucleotide polymorphism (SNP) was associated with a decrease in risk [odds ratio (OR) 0.43; 95% confidence interval (CI) 0.21–0.87], whereas the FGB − 455G/A SNP might have increased the risk (OR 1.76; 95% CI  0.7–4.03). The risk of myocardial infarction was not altered for either SNP (FGA Thr312Ala, OR 0.98, 95% CI  0.40–2.40; FGB − 455G/A, OR 0.98, 95% CI  0.40–2.40). Conclusions: With the genetic variations as markers of plasma fibrinogen levels alterations, thereby ruling out confounding and reverse causation, our results suggest that plasma fibrinogen levels could play a more pronounced role as risk factors for ischemic stroke than for myocardial infarction.     

ACE DD genotype: an independent predisposition factor to venous thromboembolism

BACKGROUND: The renin angiotensin system affects haemostasis through different mechanisms; data on the possible role of angiotensin-converting enzyme I/D polymorphism in the pathogenesis of deep venous thrombosis are conflicting, and no information is available regarding the A1166C polymorphism of the angiotensin type 1 receptor gene. In order to investigate this issue, angiotensin-converting enzyme and AT1R polymorphisms were genotyped in 336 consecutive venous thromboembolism patients and 378 controls. MATERIALS AND METHODS: Haemostasis-related risk factors have been evaluated by routine tests. Factor V Leiden, Factor II (G20210A), angiotensin-converting enzyme (I/D), and angiotensin type 1 receptor (A1166C) polymorphisms have been identified by molecular analysis. RESULTS: We documented a significant association between angiotensin-converting enzyme DD genotype and venous thromboembolism (OR=2.19 95%CI 1.51-3.17 adjusted for acquired and haemostasis-related risk factors, P<0.0001); in patients with haemostasis-related risk factors, angiotensin-converting enzyme DD genotype modified the risk of venous thromboembolism in hyperhomocysteinaemic and Factor V Leiden patients and was associated with the risk of recurrent venous thromboembolism (OR=1.83 95%CI 1.06-3.17 P=0.03). In patients without haemostasis-related risk factors the angiotensin-converting enzyme DD genotype was still an independent predictor of venous thromboembolism (OR=3.29 95%CI 2.17-4.98 adjusted for acquired risk factors, P<0.0001). No significant association between the angiotensin type 1 receptor CC genotype and venous thromboembolism was found. CONCLUSIONS: This study shows that angiotensin-converting enzyme DD genotype represents a susceptibility marker of thrombosis in subjects apparently without predisposing factors and traditional thrombophilic alterations, and increases the risk of venous thromboembolism in subjects in whom a thrombogenic condition occurs. Moreover, angiotensin-converting enzyme DD genotype may be considered a new predisposing factor to venous thromboembolism recurrence.     

The β fibrinogen gene G-455-A polymorphism is a risk factor for Legg–Perthes disease

Summary  Legg–Perthes disease is a pediatric hip disorder characterized by avascular necrosis of the femoral head. The etiology of Legg–Perthes disease may involve repeated interruptions of the blood supply to the proximal femur. Thus, the role of thrombosis in Legg–Perthes disease is of interest. The focus of this analysis is an evaluation of the relationship between Legg–Perthes disease and the β fibrinogen gene G-455-A polymorphism in 55 cases of Legg–Perthes disease and 56 age, race, and gender-matched healthy controls. Parents of subjects completed a questionnaire about their child's lifestyle and medical history. Blood was obtained for plasma and DNA analysis. Study subjects were predominantly white (93%), male (77%) and under age 16 (70%). Cases were more likely to be exposed to passive smoke than were controls (odds ratio 5.6, 95% confidence interval 2.0–12.0). Assuming a dominant genetic model, individuals who possessed either the G/A or A/A genotype were over three times more likely to have Legg–Perthes disease compared to those without the polymorphism (odds ratio 3.4, 95% confidence interval 1.5–7.8). Separate analyzes by smoke exposure revealed that the excess risk of the G-455-A polymorphism occurred in those exposed (odds ratio 7.0) as opposed to those unexposed to passive smoke (odds ratio 1.9). Although this difference in the odds ratios is not statistically significant ( P  = 0.2), it suggests a possible interactive effect of cigarette smoke and the b fibrinogen gene G-455-A polymorphism in the risk of developing Legg–Perthes disease.     

β-纤维蛋白原-455G/A基因多态性与新疆哈萨克族冠心病的关系

目的分析β纤维蛋白原(FGB)基因启动子区-455 bp位点多态性与新疆哈萨克族冠心病(CHD)的关系。方法采用聚合酶链式反应-限制性片段长度多态性分析法检测新疆哈萨克族220例CHD患者和200例正常对照者的FGB基因启动子区-455 bp位点多态性,并测定血浆纤维蛋白原(Fg)水平。结果①CHD组GA/AA基因型及A等位基因含量均高于对照组,差异有统计学意义(P均<0.05);②CHD组各基因型的Fg水平均高于对照组同种基因型,在CHD和对照组中,不同基因型Fg水平,以AA基因型为最高,GG基因型为最低,组间比较差异均有统计学意义(P<0.05)。结论β纤维蛋白原基因启动子区-455 bp位点多态性与新疆哈萨克族CHD有关,A等位基因是CHD的易感危险因素,可能通过影响Fg水平与CHD产生联系。     

Genetic variations observed in arterial and venous thromboembolism--relevance for therapy, risk prevention and prognosis.

We undertook genetic and biochemical assays in patients with arterial (n = 146) and venous (n = 199) thromboembolism and survivors of pulmonary embolism (n = 58) to study causation and gene-life style interactions. In the clinical material from North Western Russia, factor V Leiden was found to be a risk factor in venous thrombosis (OR = 3.6), while the methylenetetrahydrofolate reductase (MTHFR) C677T mutation was a significant variable in both venous (p = 0.03) and arterial thrombosis (p = 0.004). Homocysteine levels were determined (n = 84) and hyperhomocysteinemia correlated with the T allele of the MTHFR gene, and with smoking and coffee consumption. Vitamin supplementation reduced homocysteine levels dependent on MTHFR genotype (36% TT, 25% CT, 22% CC). In pulmonary embolism patients, frequency of the -455G/A beta-fibrinogen dimorphism was studied. Carriers of this allele were significantly underrepresented (p < 0.02) among pulmonary embolism survivors (34.5%) compared to controls (56.7%). Additionally, -455AA homozygotes were found in 11.7% controls but only 1.7% of pulmonary embolism patients (p = 0.006). In venous and arterial thrombosis cases, MTHFR and homocysteine data led to effective dietary supplementation with a reduced risk of disease progression. Results from the pulmonary embolism study may indicate that screening tests for the -455G/A beta-fibrinogen genetic variation could be of prognostic value, and may point the way for novel anticoagulation strategies.     

内皮细胞蛋白C受体基因6936A/G多态性和深静脉血栓形成相关性研究

目的 通过病例对照研究,了解内皮细胞蛋白C受体(EPCR)基因6936A/G多态性和深静脉血栓形成(DVT)的相关性,进一步了解EPCR在DVT形成中的重要性.方法 用ELISA法检测65例DVT患者和71名健康体检者的外周血血浆可溶性EPCR(sEPCR)水平;提取血细胞中的DNA,PCR扩增后将目的 片段EPCR基因直接测序,分析EPCR基因第6936位点的多态性.结果 ①正常对照组中,AG基因型组血浆sEPCR水平[(0.97±0.32)ng/L]明显高于AA基因型组[(0.61±0.24)ng/L](P＜0.01);DVT患者组中AG基因型组[(0.87±0.21)ng/L]亦明显高于AA基因型组[(0.50±0.18)ng/L](P＜0.01).②DVT组的血浆sEPCR水平[(0.68±0.32)ng/L]明显高于正常对照组[(0.54±0.22)ng/L](P＜0.05).③EPCR基因6936位点AG基因型分布频率DVT组高于正常对照组(P＜0.05).④AG基因型患DVT的危险性较AA基因型高(OR=2.75,95%可信区间为1.04～7.30)(P＜0.05).结论 血浆sEPCR水平与EPCR基因6936A/G多态性有关.DVT患者血浆sEPCR水平较正常人增高.EPCR基因6936 AG基因型者可能患DVT的风险高.     

A common mutation (G-455--> A) in the beta-fibrinogen promoter is an independent predictor of plasma fibrinogen, but not of ischemic heart disease. A study of 9,127 individuals based on the Copenhagen City Heart Study.

A common mutation (G-455--> A) in the promoter region of the beta-fibrinogen gene has been associated with elevated plasma fibrinogen levels. Whether fibrinogen genotype affects plasma fibrinogen levels and risk of ischemic heart disease in the general population has not been studied. We investigated the association between fibrinogen genotype, plasma fibrinogen levels, and ischemic heart disease in a general population sample (n = 9,127). The A-allele (relative frequency, 0.20) was associated with elevated plasma fibrinogen levels in both genders (P < 0.001). While the effect of the A-allele on fibrinogen level was additive in men, the effect was dominant in postmenopausal women. The A-allele raising effect appeared to be two- to threefold greater in individuals with ischemic heart disease than in those without. An increase of 1 SD in plasma fibrinogen increased the odds ratio for ischemic heart disease by approximately 20% (P < 0.01 for women and < 0.005 for men). However, the frequency of the A-allele was similar in those with and without ischemic heart disease, and genotype was not a predictor of disease. These results demonstrate that the (G-455--> A) mutation in the promoter region of the beta-fibrinogen gene is associated with an increase in plasma fibrinogen in both genders in the general population. This increase does not appear to cause ischemic heart disease.     

Protein C -1641 AA is associated with decreased survival and more organ dysfunction in severe sepsis

OBJECTIVE: Protein C contains an A/G polymorphism at position -1641 and a C/T polymorphism at -1654 associated with risk of deep venous thrombosis. We tested the hypothesis that these polymorphisms are associated with altered outcome in patients having severe sepsis, in which protein C is a central molecule. DESIGN: Prospective cohorts, gene-association study. SETTING: Tertiary care medical/surgical intensive care unit. PATIENTS: We first recruited a derivation cohort of patients having severe sepsis (n = 62). A second replication cohort was similarly defined but larger (n = 402). We tested for biological plausibility in a third cohort of post-cardiopulmonary bypass patients (n = 61). INTERVENTIONS: Patients were genotyped at protein C -1641 and -1654. MEASUREMENTS AND MAIN RESULTS: The primary outcome variable was survival in cohorts 1 and 2 and postoperative serum interleukin-6 concentration in cohort 3. Severity of individual organ dysfunctions and systemic inflammation were secondary outcome variables. In the first derivation cohort, the protein C -1641 AA genotype was associated with decreased 28-day survival (p < .05). This finding was confirmed in the much larger replication cohort of patients having severe sepsis (p = .028). In addition, the protein C -1641 AA genotype was associated with significantly more organ dysfunction and more clinical evidence of systemic inflammation (p < .05). Furthermore, the -1641 AA genotype was associated with increased serum interleukin-6 at 4 and 24 hrs after cardiopulmonary bypass (p = .024). There was no association of -1654 A/G with phenotype in any cohort. CONCLUSIONS: Protein C -1641 AA genotype is associated with decreased survival, more organ dysfunction, and more systemic inflammation in patients having severe sepsis and with increased interleukin-6 levels after cardiopulmonary bypass surgery.     

AMI is associated with polymorphisms in the NOS3 and FGB but not in PAI-1 genes in young adults

BACKGROUND: We investigated the relationship between NOS3, FGB and PAI-1 polymorphisms and endothelial dysfunction and risk factors for acute myocardial infarction (AMI) in young adults. METHODS: Endothelial function was measured by response to flow mediated vasodilation (FMV) and induced by nitrate (FMN). Biochemical parameters were measured by standard enzymatic methods and plasma total nitrate was analyzed by the NOA system. NOS3 (T-786C, G894T and intron 4A/B STR), FGB (C-148T and G-455A) and PAI-1 (4G/5G) polymorphisms were determined by PCR-RFLP. RESULTS: Concentrations of total and LDL cholesterol, apo B, triglycerides, nitrate, PAI-1 and fibrinogen were higher and apo AI, HDL cholesterol and FMV were lower in AMI patients than in controls (p<0.001). PAI-1 (p<0.001) but not nitrate was higher in AMI patients with low response to FMV. NOS3 T-786C and FGB C-148T polymorphisms were associated with AMI (p<0.050). NOS3 T-786C was also related to hypertension (p=0.049). NOS3 intron 4A/B STR was associated with increased concentrations of total cholesterol and apo B. NOS3-786TT/894GT haplotype was associated with increased FMV (p=0.018) than the other haplotypes. CONCLUSIONS: Our data suggest NOS3 and FGB polymorphisms are associated with AMI. NOS3 is also related to hypertension, endothelial dysfunction and variation on serum cholesterol in young adults with AMI.     

Role for mitochondrial uncoupling protein-2 (UCP2) in hyperhomocysteinemia and venous thrombosis risk?

BACKGROUND: Hyperhomocysteinemia has been associated with an increased risk of venous thrombosis, which might be mediated through an oxidative stress dependent mechanism. The function of uncoupling protein-2 (UCP2) is still under debate, but it has been suggested to play a role in reduction of mitochondrial reactive oxygen species. In the present study, we investigated whether the 45 bp deletion/insertion (del/ ins) polymorphism in the UCP2 gene is associated with elevated homocysteine levels and whether it might be associated with an increased risk of recurrent venous thrombosis (RVT). METHODS: The 45 bp del/ins polymorphism in the UCP2 gene was genotyped by PCR analysis in 161 RVT cases and 386 controls of Caucasian origin in which fasting- and post-load homocysteine levels were previously determined. Statistical analysis was performed to assess whether the UCP2 45 bp del/ins polymorphism was associated with plasma total homocysteine levels and venous thrombosis risk. RESULTS: Post-load homocysteine levels were positively associated with UCP2 45 bp ins/ins genotype (P = 0.02). None of the UCP2 45 bp ins/del genotypes were associated with fasting plasma homocysteine levels. The frequency of the UCP2 45 bp ins/ins genotype was 12.4% in RVT cases compared to 8.3% in controls, which resulted in an odds ratio of 1.8 (95% CI 1.0-3.4). CONCLUSIONS: The results of our study show that the common 45 bp del/ins polymorphism in the UCP2 gene is associated with hyperhomocysteinemia, which might increase the risk of venous thrombosis. However, the mechanism is not fully understood and additional studies should be performed to confirm our findings.     

迟发性阿尔茨海默病的肿瘤坏死因子-αG-308A基因多态性研究

目的 探讨迟发性阿尔茨海默病的肿瘤坏死因子-α G-308A基因多态性.方法 将57例迟发性阿尔茨海默病患者设为研究组,抽取52例健康志愿者设为对照组,采用聚合酶链反应、限制性片段长度多态性方法检测两组肿瘤坏死因子-α G-308A多态性. 结果 两组脂蛋白E-4等位基因分布显著不同（χ2=19.39,P〈0.01）,脂蛋白E-4等位基因携带者罹患迟发性阿尔茨海默病风险很高（OR=2.49,95%CI 1.53-4.07,P〈0.01）;肿瘤坏死因子-αAA基因与脂蛋白E-4等位基因的交互作用致迟发性阿尔茨海默病风险增高（χ2=6.34,P〈0.05）;研究组脂蛋白E-4等位基因非携带者中,AA、AG基因型频率,A-等位基因频率显著高于对照组（χ2=5.26、4.58,P〈0.05）. 结论 肿瘤坏死因子-α G-308A基因多态性可能增加迟发性阿尔茨海默病发病风险,同时这种多态性与脂蛋白E-4等位基因状态有关.     

Prospective study of the A455V polymorphism in the thrombomodulin gene, plasma thrombomodulin, and incidence of venous thromboembolism: the LITE Study

Summary.  Plasma thrombomodulin (soluble TM; sTM) is considered to be a marker of endothelial injury, but a recent report indicated that the relationship of sTM with thrombosis is complex. Venous thromboembolic events were identified in adults in two longitudinal cohort studies, the Atherosclerosis Risk in Communities Study and the Cardiovascular Health Study, totaling 21 690 participants. After 8 years of follow-up, sTM was measured in baseline plasma of 305 participants who developed venous thrombosis and 607 who did not. Thrombomodulin A455V genotype was determined in 302 cases and 626 controls. There was no difference in the prevalence of the three TM genotypes between cases and controls and no difference in age-adjusted mean values of sTM by genotype. There were no associations of age-adjusted sTM or TMA455V genotype with overall venous thromboembolism or with thrombosis in any subtype of venous thromboembolism.     

血小板反应素-1基因G1678A多态性与急性冠脉综合征的相关性

目的 探讨血小板反应素-1(thrombospondin-1,TSP-1)基困G1678A(Ala523Thr)多态性与中国汉族人群急性冠脉综合征(ACS)的可能关系.方法 采用病例对照研究,病例均选自2003年11月至2006年5月在江苏大学附属武进医院等4家医院住院的患者,其中ACS患者412例,病例均符合2002年AHA/ACC关于ACS诊断指南的诊断指标;同期选择年龄、性别相匹配的经相关检查排除冠心病者319例为对照.应用聚合酶链反应.限制性片段长度多态性(PCR-RFLP)方法检测TSP-1 G1678A多态性.结果 ACS患者TSP-1 G1678A多态性从基因型频率(49.5%)明显高于对照组(40.4%),两组差异有统计学意义(P=0.015).GA和GG基因型在ACS组和对照组的分布差异无统计学意义(GA:39.3%vs.46.1%,P=0.070;GG:11.2%vs.13.5%,P=0.340).A等位基因频率在ACS组和对照组分别为69.2%、63.5%(P=0.022).多元logistic回归分析显示,TSP-1基因AA基因型与ACS的发生具有显著相关性(OR=1.52;95%CI:1.11～2.08;P=0.010).结论 TSP-1基因G1678A多态性与中国汉族人群ACS密切相关,从基因型可能是ACS遗传易感性的基因标记之一.     

Association between patterns of nucleotide variation across the three fibrinogen genes and plasma fibrinogen levels: the Coronary Artery Risk Development in Young Adults (CARDIA) study

BACKGROUND: Previous genotype-phenotype association studies of fibrinogen have been limited by incomplete knowledge of genomic sequence variation within and between major ethnic groups in FGB, FGA, and FGG. METHODS: We characterized the linkage disequilibrium patterns and haplotype structure across the human fibrinogen gene locus in European- and African-American populations. We analyzed the association between common polymorphisms in the fibrinogen genes and circulating levels of both 'functional' fibrinogen (measured by the Clauss clotting rate method) and total fibrinogen (measured by immunonephelometry) in a large, multi-center, bi-racial cohort of young US adults. RESULTS: A common haplotype tagged by the A minor allele of the well-studied FGB-455 G/A promoter polymorphism (FGB 1437) was confirmed to be strongly associated with increased plasma fibrinogen levels. Two non-coding variants specific to African-American chromosomes, FGA 3845 A and FGG 5729 G, were each associated with lower plasma fibrinogen levels. In European-Americans, a common haplotype tagged by FGA Thr312Ala and several other variant alleles across the fibrinogen gene locus was strongly associated with decreased fibrinogen levels as measured by functional assay, but not by immunoassay. Overall, common polymorphisms within the three fibrinogen genes explain < 2% of the variability in plasma fibrinogen concentration. CONCLUSIONS: In young adults, fibrinogen multi-locus genotypes are associated with plasma fibrinogen levels. The specific single nucleotide polymorphism and haplotype patterns for these associations differ according to population and also according to phenotypic assay. It is likely that a substantial proportion of the heritable component of plasma fibrinogen concentration is due to genetic variation outside the three fibrinogen genes.     

老年高血压病患者心房颤动易感性与C-反应蛋白-717A/G多态性的关系

目的探讨C-反应蛋白（CRP）-717A/G多态性与老年高血压病患者心房颤动易感性的关系。方法选择75例合并心房颤动（房颤组）及94例无心房颤动（对照组）的老年高血压病患者,聚合酶链反应-限制性片段长度多态性（PCR-RFLP）方法检测CRP-717A/G基因型,比较两组基因型及等位基因频率分布,以及各基因型对血脂参数、高敏C反应蛋白（hs-CRP）的影响。结果房颤组hs-CRP水平（P=0.000 0）及左心房直径（P=0.000 0）均显著高于对照组,房颤组AA基因型频率（P=0.025 3）及A等位基因频率也显著高于对照组（P=0.028 0）。无论是房颤组抑或对照组,均未发现CRP-717A/G多态性对各临床参数有影响。结论老年高血压病合并房颤患者hs-CRP水平显著升高,CRP-717 A等位基因与房颤易感性相关。     

血管紧张素原基因部分多态性指标与原发性高血压的发病风险:社区病例对照

背景:血管紧张素原基因是第一个被发现的原发性高血压候选基因,T174M5和M235T多态均位于AGT基因第二外显子,且存在连锁不平衡。启动子区域A-6G和G-217A位点多态对其基因表达起重要调节作用,且血管紧张素原基因的表达产物与血压水平的维持密切相关。目的:探讨血管紧张素原基因A-6G,T174M和G-217A位点多态性与中国汉族人群原发性高血压发病风险的关系。设计:整群抽样,病例-对照分析。单位:南京医科大学第一附属医院老年医学科与心血管科,国家人类基因组南方研究中心,江苏省东台市人民医院心血管科。对象:实验于2005-09/10在江苏省东台市农村完成。①263例实验对象均来自江苏省盐城市东台县农村,其中原发性高血压组177例为未经药物治疗的原发性高血压患者,高血压的诊断参照1999年WHO/ISH高血压诊断标准(收缩压≥140mmHg和/或舒张压≥90mmHg);正常对照组86例。②纳入标准:实验对象为汉族;长期居住本地非外来人口;能清楚回答问题;经病史、临床症状、体征及辅助检查确诊;统一问卷面访调查资料完整。③排除标准:原发性高血压组排除继发性高血压,正常对照组排除高血压家族史,同时两组人群均排除肝、肾慢性疾病和糖尿病。方法:采集外周静脉血3mL,用FlexiGeneDNAKit(250)提取人外周血中DNA。应用primer3软件进行引物设计,并排除引物序列中的多态位点。多重聚合酶链反应扩增后,取3μL反应产物用琼脂糖凝胶电泳检测扩增结果,扩增成功的聚合酶链反应产物用QIAquickPCRPurifica-tionKit纯化,纯化后的产物用DNaseⅠ片段化,片段化的酶切产物以脱氧核苷酸末端转移酶进行荧光素标记。每个单核苷酸多态各设计2条等位基因特异性探针和1条错配探针,芯片用OmniGridTM100点样仪制备,每个探针重复3次,形成3个阵列。杂交液95℃变性10min后,立即置于冰上冷切,取10μL杂交液加入到芯片矩阵上,50℃杂交2h,然后洗涤,甩干。GenePix4000B共聚焦激光扫描仪进行芯片扫描,利用GenePixPro提取得到每条探针的荧光信号强度值,通过计算每个单核苷酸多态的等位基因分数判断基因型。主要观察指标:①两组血管紧张素原基因各多态位点基因型分布频率的比较。②血管紧张素原基因A-6G和T174M位点多态性与原发性高血压发病风险的相关分析。③两组血管紧张素原基因A-6G,T174M和G-217A位点多态性对血压的影响。结果:按意向处理分析,263例实验对象均进入结果分析。①血管紧张素原基因A-6G位点AA,AG,GG基因型(P=0.014)以及A,G等位基因频率(P=0.004,OR=0.44)差异明显;T174M位点CC,CT,TT基因型(P=0.031)以及C,T等位基因频率(P=0.014,OR=0.55)差异有显著性意义;未发现G-217A位点GG,AG,AA基因型(P=0.722)以及G,A等位基因频率(P=0.403,OR=0.80)有明显差异。②携带A-6G多态AA基因型和T174M多态CC基因型的个体发生原发性高血压的风险分别减少57%(95%可信区间=0.23～0.82,P=0.010)和56%(95%可信区间=0.25～0.79,P=0.006)。③两组血管紧张素原基因A-6G,T174M和G-217A位点各基因型的收缩压、舒张压和平均动脉压的差异均无显著性意义(F=0.100～2.911,P均>0.05)。结论:血管紧张素原基因A-6G位点AA基因型和T174M位点CC基因型可能会减少中国汉族人群原发性高血压发病风险,未发现G-217A多态基因型与其有显著相关性。     

Low-density lipoprotein receptor-related protein 1 polymorphism 663 C > T affects clotting factor VIII activity and increases the risk of venous thromboembolism

BACKGROUND: Clotting factor (F) VIII is an independent risk factor for primary and recurrent venous thromboembolism (VTE). The causes for high plasma FVIII levels are not fully understood, but an involvement of genetic factors has been demonstrated. A multifunctional endocytic receptor, low-density lipoprotein receptor-related protein 1 (LRP1), mediates cellular uptake and subsequent degradation of FVIII and may contribute to variations in FVIII levels. OBJECTIVE: We assessed the association of a genetic variation of LRP1 (663C > T) with basal FVIII levels and the risk of venous thrombosis in a group of high-risk patients and in healthy controls. PATIENTS AND METHODS: One hundred and fifty-two patients with a history of recurrent VTE (median age 56 years, 47% women) were compared with 198 age- and sex-matched controls (median age 53 years, 50% women). The LRP1 663C > T genotype was analyzed by mutagenic separated polymerase chain reaction assay and heterozygosity was confirmed by sequence analysis. RESULTS: LRP1 663C > T genotype distribution differed significantly between patients (663CC n = 138, 663CT n = 14) and controls (663CC n = 190, 663CT n = 8; P = 0.048). In multivariable linear regression analysis including LRP1 663C > T, ABO blood group, von Willebrand factor antigen, C-reactive protein and age, LRP1 663CT was independently associated with FVIII activity (P = 0.02). LRP1 663CT was also associated with increased odds for VTE following adjustment for blood group O, FV Leiden and the prothrombin variation 20210G > A in multivariate analysis (odds ratio 3.3, 95% CI 1.3-8.5). CONCLUSIONS: According to our data the LRP1 663C > T polymorphism influences plasma FVIII levels independently of blood group, C-reactive protein and von Willebrand factor and is significantly associated with the risk of VTE.     

Endothelin-converting enzyme-1b C-338A polymorphism is associated with the increased risk of coronary artery disease in Chinese population

BACKGROUND: Endothelin-converting enzyme-1 (ECE-1), the key enzyme responsible for endothelin-1 generation, has been linked to coronary artery disease (CAD). Recently, a genetic polymorphism (ECE-1b C-338A) located in ECE-1 gene promoter was identified. However, it is unclear whether this polymorphism is associated with the risk of CAD. METHODS: We conducted a study with CAD patients and controls matched by age and sex to examine the prevalence of ECE-1b C-338A polymorphism in CAD. RESULTS: The frequencies of ECE-1b-338CC, CA, and AA genotypes in cases (40.1%, 42.2%, and 17.7%) were significantly different from those of controls (50.6%, 40.5%, and 8.9%, chi2=9.989, P=0.007). Subjects with the variant genotypes (CA+ AA) had a 58% increased risk of CAD relative to CC carriers (adjusted OR=1.58, 95% CI=1.07-2.32). Furthermore, the adjusted OR of AA genotype for CAD was 2.33 (95% CI=1.25-4.35). In stratified analyses, the A allele was significantly associated with increased risk of CAD in female (adjusted OR=2.86, 95% CI=1.40-5.84) and subjects with age >or= 64 y (adjusted OR=2.96, 95% CI=1.73-5.08). Moreover, the frequency of patients with variant genotypes increased gradually from single- to triple-vessel disease although without statistical significance (P=0.069 for trend). CONCLUSION: Our results suggested that ECE-1b-338C to A variant might be associated with increased risk of CAD in Chinese population.     

血管紧张素原基因多态性与血管性认知障碍关系的研究

目的 探讨血管紧张素原(AGT)基因G-6A和M235T多态性与血管性认知障碍(VCI)的关系.方法 采用随机对照研究,聚合酶链反应(PCR)方法检测VCI组(67例)、正常对照组(71例)AGT基因G-6A和M235T多态性.结果 VCI组AGT基因M235TT等位基因频率0.73,TT基因型频率0.52,与对照组(0.68,0.45)比较差异无统计学意义(P0.05),TT基因型对VCI的比数比为0.544(95%CI为0.208～1.424,P0.05).VCI组AGT基因G-6 A等位基因频率0.69,AA基因型频率0.48,与对照组(0.63,0.39)比较差异无统计学意义(P0.05),AA基因型对VCI的比数比为0.602(95%CI为0.252～1.738.P0.05).结论 脑梗死伴血管性认知障碍患者与AGT基因G-6A和M235T多态性无关,AGT基因这两个位点多态性未参与发病.     

湖北汉族人群APOC3-455T》C基因多态性与MS的相关性

目的 探讨载脂蛋白C3(APOC3)-455T>C基因多态性与湖北汉族人群代谢综合征(MS)及血脂的关系.方法 采集226例MS患者和258名健康者(对照组)血液用聚合酶链反应限制性片段长度多态性(PCR-RFLP)分析APOC3-455T>C基因多态性的分布,并检测其血脂和血糖水平.结果 -455C等位基因在MS与对照组中的分布频率不同,差异有统计学意义(P<0.05).两组中C等位基因携带者三酰甘油(TG)水平比TT纯合子者高(P<0.05),而高密度脂蛋白胆固醇(HDL-C)水平比TT纯合子者低.APOC3等位基因是MS独立影响因子(OR=1.987,P=0.038).结论 POC3-455T>C基因多态性与血脂水平特别是TG及HDL-C有关,APOC3-455C等位基因可能为MS的危险因素.