【作者】 吴晓本；

【导师】 徐成伟；

【作者基本信息】 山东大学 ， 临床检验诊断学， 2009， 硕士

【摘要】 目的:通过对TAFI编码区(CPB2基因)2个单核苷酸多态性位点(505A/G,1040C/T)基因亚型分布与2型糖尿病(T2DM)发病及病程进展的相关性进行检测与分析,同时测定T2DM患者血浆中凝血酶激活的纤溶抑制物(TAFI)的抗原含量(TAFI:Ag)及其活性水平(TAFI:Act),以探究T2DM患者体内TAFI浓度与凝血-纤溶紊乱的相关性以及505A/G,1040C/T的分布差异,为揭示TAFI在T2DM发病及病程进展中的作用机理提供实验基础。方法:T2DM组患者的诊断均参照并符合1999年WHO专家委员会修订的诊断标准,组根据尿白蛋白排泄量与尿肌酐的比值(ACRs)将T2DM患者进一步分为初期T2DM患者及后期T2DM患者。研究个体包括157例T2DM患者和140例对照组个体。157例T2DM患者中男90例,女67例,39岁～80岁,平均(54.8±9.9)岁。对照组含男75例,女65例,42～83岁,平均(57.1±11.2)岁,其中病例组年龄、性别构成、体重指数(BMI)等与对照组相比较差异均无统计学意义。应用聚合酶链反应-限制性内切酶片段长度多态性(PCR-RFLP)分析技术检测157例T2DM患者(T2DM组)和140例正常对照者(对照组)的TAFI505A/G、1040C/T两位点的多态性。同时应用ELISA及发色底物法分别检测患者和对照组个体血浆中的TAFI∶Ag及TAFI∶Act活性水平。结果:本研究中CPB2基因的2个单核苷酸多态性位点为505A/G、1040C/T,其中505A/G多态性位点病例组及对照组中各基因型的分布差异无统计学意义,但在1040C/T位点T2DM组T等位基因的频率较对照组明显下降(15.6%对25.4%,P＜0.05),这主要由于病例组T/T纯合子型比例显著下降所致(P＜0.05,OR 0.33,95%CI 0.12～0.91),但这种显著性差异只呈现在初期T2DM组(P＜0.05,OR 0.20,95%CI 0.0～4-0.94)。初期T2DM患者血浆中TAFI:Ag与TAFI:Act水平分别为(119.82±35.53)%和(46.31±8.47)μg/ml,后期D2DM组患者血浆中TAFI:Ag与TAFI:Act水平分别为(130.52±46.39)%和(55.92±12.58)μg/ml,对照组个体血浆中TAFI抗原与活性水平分别为(85.2±25.24)%和(26.92±10.78)μg/ml,经方差分析,初、后期T2DM患者间TAFI:Ag与TAFI:Act差异无统计学意义(p＞0.05),T2DM组与对照组比较,TAFI:Ag与TAFI:Act均升高,差异具有统计学意义(p＜0.05)。结论:①TAFI1040C/T多态性位点与T2DM患病危险度存在关联;②T等位基因可能在T2DM早期病情进展中起保护性作用;③TAFI作为凝血与纤溶的调节因子,在T2DM患者体内的高凝血倾向中发挥重要作用,同时提示TAFI抑制物有望成为溶栓治疗的新途径。更多还原

【Abstract】 Objective: Based on the role of TAFI(thrombin activated fibrinolysis inhibitor) in balancing between the fibrinolysis and coagulation and no studies thus far have investigated the contribution of the TAFI genetic polymorphisms to type 2 diabetes mellitus(T2DM), we investigated the possible association of the TAFI activity-related two polymorphisms(505A/G、1040C/T) with increased risk of T2DM. At the same time we also carried out as a pilot study to examine the antigen and activity of TAFI in both patients and control groups.Methods: We studied the two allele frequencies of the 505A/G and 1040C/T polymorphisms which result in two amino acid substitutions: Ala for Thr at position 147 and Ile for Thr at position 325 in 157 type 2 T2DM patients and 140 healthy controls matched by age, gender, ethnicity and body mass index (BMI), using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) typing analysis. In addition, the TAFI-Ag and TAFI-Act were determined by enzyme link immunosorbent assay (ELISA) and chromogenic assay, respectively.Results: No significant differences of TAFI levels appeared between patients and controls at 505A/G. At 1040C/T ,the detected frequency for the T allele in the patients’ group was significantly smaller in comparison to that of the control group (15.6% versus25.4%, respectively: P <0.05). This difference was due to the relative decrease of T/T homozygotes in the group of patients, in comparison to controls (P < 0.05, OR 0.33, 95%CI 0.12-0.91).The same pattern of significance was also observed between controls and the subgroups of patients with initial stages of T2DM categorized by the urine albumin excretion (UAEμg/ml)-to-creatinine (mg/ml) ratios (ACRs) while no significant difference was observed between controls and patients with latter stage of T2DM.Plasma TAFI:Ag and TAFI:Act were (119.82±35.53)% and (46.31±8.47)μg/ml in initial T2DM group, (130.52±46.39)% and (55.92±12.58)μg/ml in latter T2DM group, both being significantly higher than those of control group[TAFI:Ag(85.2±25.24)% and TAFI:Act(26.92±10.78)μg/ml].Conclusion: This study clearly indicates that at 1040C/T the frequency for the T allele is strongly associated with increased risk for T2DM in a subset of the general population. These results are in accordance to previous studies of constitutive expression and secretion of TAFI in T2DM, implying that the T allele confers protection against the onset of T2DM only in homozygosity, It may function as a recessive trait. It may be due to either unidentified properties of the 1040C/T polymorphism or of a strong linkage disequilibrium undefined between this polymorphism and another genetic locus.更多还原