Study On Association Of Single Nucleotide Polymorphism Of Transforming Growth Factor-β1 Gene+869T/C Locus With Atrial Fibrillation

BackgroundAtrial fibrillation(AF) is the most common clinical arrhythmia,caused by stroke,heart failure and an important cause of death,the population incidence increases with age,but its pathogenesis is still unclear.Therefore,in the early stages of diagnosis and treatment of atrial fibrillation,the prevention of refractory atrial fibrillation and the occurrence of cardiovascular events of great significance.At present,the fibrosis in the role of cardiovascular disease is becoming a research hotspot.Science fibrosis is an important component of change in the vast majority of heart disease.Domestic and international studies have shown that cytokines in the development process of fibrotic diseases plays an important role,especially transforming growth factor-β,is considered a key fibrogenic cytokine-induced,are the strongest promoting agent in extracellular matrix deposition.TGF-β1 is one of the first to be aware of the TGF-βisoforms in the fibrotic process,TGF-β1 enable extracellular matrix protein over-expression,so that the heart of the organization, structure,shape change.These changes affect ventricular contractility,valvular function,electric impulse conduction.Studies have shown that fibrosis is maintenance and development of the basic pathophysiology in atrial fibrillation, TGF-β1 plays a very important role in the occurrence and control aspects of atrial fibrosis,and can be used as a new target in the treatment of atrial fibrillation.With the progress of genone sequencing,comprehensive and in-depth understanding of individual and inter-group variation,or genone polymorphism has become possible, and increasingly shows its importance.Therefore,further study of the relation in TGF-β1 gene polymorphisms and atrial fibrillation,in order for TGF-β1 gene therapy in atrial fibrillation diseases such as fibrosis,research and development of new therapeutic drugs of fibrosis,and slow down or prevent the fiber of further development and eventual capture of atrial fibrosis and other diseases is of great significance.Objective:We utilized the case-control study methods and the application of modern molecular biology methods in TGF-β1 gene +869T/C SNP detection,to understand the relevance of TGF-β1 gene +869T/C SNP and atrial fibrillation of Southern China Han population,and thereby to explore the role of the genetic factors in the incidence of atrial fibrillation of Southern China Han population at the molecular level.Subjects:All subjects are from September 2006～November 2008 Guangdong Province, total of 212 cases.Atrial fibrillation group inclusion criteria:(1) atrial fibrillation confirmed by the surface ECG or Holter monitoring.(2) age≤75 years old,body mass index(BMI)≤28.(3)excluded the following diseases:isolated atrial fibrillation,Wolff-Parkinson-White syndrome,valvular heart disease,congenital heart disease,pulmonary disease,cardiomyopathy,myocarditis,thyroid dysfunction, liver disease,chest after major surgery,pericarditis,diabetes,blood disease, electrolyte disorders,thromboembolic disease,connective tissue diseases and autoimmune diseases.(4) All patients had no long-term drinking habits,as women are pregnancy or oral contraceptives history;liver function,blood sugar,chest, abdominal B-(including the liver,gallbladder,spleen,pancreas,renal and adrenal), such as inspection normal.Control group selection criteria:Asked by history or ECG and Holter monitoring has never been confirmed that atrial fibrillation occurred more than meet the healthy standard.The above study are in southern China Han population(non-kinship),and has been informed consent.Based on the above criteria,a total of 103 cases of selected patients with atrial fibrillation,the average age at onset of(62.13±6.79) years old.One of 59 cases of male,female 44 cases,49 cases of hypertension,54 cases of patients with coronary heart disease(36 cases at the same time suffering from hypertension and coronary heart disease);selected 109 cases of healthy controls,average age(61.64±7.63) years old,one of 64 cases of male,female 45 cases,51 cases of hypertension,58 cases of patients with coronary heart disease(42 cases at the same time suffering from hypertension and coronary heart disease);Methods:Both groups were set up observation of clinical data form,a detailed record of the age,sex,height,weight,smoking,such as the general situation of patients;TC, TG,HDL-C,LDL-C,left atrial diameter,LVEF,such as check indicators;as well as hypertension,coronary heart disease,diabetes and other medical history.All subjects taken fasting venous blood,EDTA anticoagulant,using Po Biology Engineering(Dalian) Co.,Ltd.Blood Genomic DNA Extraction Kit extract genomic DNA.The detection of TGF-β1 genotypes utilized sequence specific primer polymerase chain reaction.Statistical analysis: SPSS13.0 statistical software was used.Measurement data which meet the normal distribution of mean±standard deviation,the count data of said frequency. Balance of genetic testing utilize Hardy-Weinberg law of balance,to compare the groups of count data utilize testing X~2.Compared the groups of normal distribution measurement data by homogeneity of variance test,homogeneity of variance compared using by one-way ANOVA,multiple comparisons between groups using LSD method;two-sample comparison between the mean homogeneity from using an independent samples t test,variance from the use of irregular t 'test.Skew the distribution of measurement data into normal data processing,such as non-appropriate way into the use of non-parametric test,comparing the two groups using Wilcoxon rank sum test,multi-group by Kruskal-Wallis H test.Single-variable logistic regression analysis to explore the relationship between gene polymorphism and atrial fibrillation occurred,calculated odds ratio(odds ratio,OR) and 95% confidence interval(95%CI).Standard testα=0.05.Results:1.TGF-β1 gene +869T/C locus SNP exists in Southern China Han population, and three kinds of genotype existed.2%agarose gel electrophoresis analysis of the results:TGF-β1 gene +869T/C locus PCR amplification products,1 for the TT genotype,2 for the TC genotype,3 for the CC genotype.2.Atrial fibrillation and control groups between the age,sex,body mass index (BMI),smoking,hypertension,coronary heart disease,HDL-C,LDL-C,TG,TC was no significant difference.The value of P is 0.627,0.833,0.772,0.194,0.909,0.731,0.412,0.587,0.753,0.327.While the atrial fibrillation group and the control group between the LVEF,left atrial diameter were significantly different.The value of P is 0.000,0.000.3.Atrial fibrillation group TGF-β1 gene +869T/C locus TT,TC and CC-type frequency distribution compared with the control group the differences were significant(χ~2 = 8.772,P＜0.05).Atrial fibrillation group TGF-β1 gene +869T/C locus the distribution of CC-type frequency higher than control group.Atrial fibrillation group TGF-β1 gene +869T/C locus allele frequency distribution compared with the control group is significant difference(χ~2 = 8.967,P＜0.05). Atrial fibrillation group TGF-β1 gene +869T/C locus the distribution of C allele frequency higher than control group.4.Univariate logistic regression analysis the relationship between TGF-β1 gene +869T/C SNP and atrial fibrillation,in terms of relative TT genotypes,TC + CC genotype and homozygous mutant CC type,a significant increase the risk of atrial fibrillation,OR value(95%CI) were 1.862(1.013～3.421),3.043(1.421～6.518),P values were 0.045,0.004.The OR values(95%CI) of TC hybrid is 1.430(0.744 2.749),P = 0.284.The relative risk of TGF-β1 gene +869T/C locus C allele gene in atrial fibrillation,in terms of relative T allele,the patients carrying C allele significantly increased the risk of atrial fibrillation,OR value(95%CI) to 1.797 (1.223～2.642),P = 0.003.5.The variance F value of three genotypes in left atrial diameter analysis is 5.186,P value is 0.006.There is statistical significance of analysis of variance in left atrial diameter between the two genotypes compared using LSD-t test,the level of left atrial diameter between TT and TC,CC genotype exist significant difference,P were 0.009 and 0.013,there was no significant difference between TC and CC genotype in the level of left atrial diameter,P was 0.967.Conclusion:1.TGF-β1 +869T/C gene polymorphism exists in Southern China Han population.2.There is a clear correlation between TGF-β1 gene +869T/C SNP and the incidence of atrial fibrillation in Southern China Han population,T alleles are atrial fibrillation occurred in the protection of genetic,C allele are atrial fibrillation susceptibility gene.3.There is a clear correlation between TGF-β1 gene +869 T / C locus SNP and the size of left atrial diameter:TT＜TC＜CC.4.The possible impact of TGF-β1 gene +869T/C SNP on the occurrence of atrial fibrillation mechanisms:can promote a high degree of TGF-β1 expression and the promotion of left atrial structural remodeling,thus increasing the risk of the incidence of atrial fibrillation.