The Correlation Between The Leptin Gene Promoter C2549A And Early Onset Coronary Heart Disease And GPIb On Platelet Membrane

ObgectiveTo study the association of polymorphism of leptin gene promoter C2549A with early onset cornorary disease,then to find out the risk gene of cornorary heart disease; to make clear the mechanism of hyperleptinemia; and to investigate the relationship of the polymorphism of leptin gene promoter C2549A and the activiation of the platelet.Methods1.Among the inpatients of Department of Cardiology in the first central hospital,selecting the male<55years old,the female<65years old, who had to underwent coronary angiography,according to the angiographic results, a total of200patients were included in the group of premature coronary heart disease,100persons with negative cornoray arteriograohy were included in normal control group. The two groups of subjects were surveyed the family history of coronary heart disease,measured the height,weight,waistline,hiplin, and were detected the Fasting lipid profile,FBG(fasting blood-glucose),insulin,blood pressure and serum leptin level.2.Measurement of serum leptin level adopting the method of ELISA.3. The percentage of positive platelet membrane GPIb and the average fluorescence intensity were quantified by flow cytometry.4. Genomic DNA was extracted from leukocyte separated from the fasting venous blood of the objects.Amplication and detection of the polymorphism of the C2549A clips of human leptin gene promoter was accomplished by polymerase chain reaction-Restriction fragment length polymorphism analysis and the sequencing technology.Analysising the constitute ratio of the C2549A genotypes of the Early onset coronary heart disease group and the normal control group. Comparing the serum leptin level and the percentage of positive platelet membrane GPIb and its average fluorescence intensity among the C2549A genotypes. Results1.Compared with the normal control group,the serum leptin level of the premature cornorary heart disease group was significantly higher. The percentage of positive platelet membrane GPIb and its average fluorescence intensity was markedly reduced(all p<0.05).2.The genotype distribution of the leptin gene promoter C2549A met The Hardy-Weingerg principal.The genotype frequencies of AA, AC and CC of the C2549A were32.5%,0.0%and17.5%in premature heart disease patients respectively, the percentage of the genotype frequencies of AA、AC and CCwere17.0%、46.0%and37.0%in the controls seperately.TheAand C allele frequencies in the early onset cornorary disease group were57.5%and42.5%seperately,which was40.0%and60.0%respectively in the normal control group, The A allele frequencies in the premature heart disease were siginificantly higher than that in the control group (all p<0.05)3.Compared with other genotypes,the serum leptin levels of the AA genotype persons increased both in the two groups of the permature cornorary heart disease and the normal control, difference was statistically significant(all p<0.05).4. The percentage of positive platelet membrane GPIb and the fluorescence intensity in subjects with AA homozygote were markedly lower than that of AC andCC genotype both in the heart disease and control groups (all p<0.05)5. Multiple logistic regression analysis showed that AA genotype of the C2549A was independently related to the occurrence of early onset cornorary disease(OR=2.015, p<0.05).Conclusion1. The polymorphism of promoter region C2549A of the leptin gene probablely has revelance to premature heart disease,the A allele may be the risk gene of premature coronary heart disease.2. The A allele of promoter region C2549A of the leptin gene probablely lead to the high level of the serum leptin,which maybe one of the molecular mechanisms of the hyperleptinemia. 3. Compared with other genotypes, the degree of platelet activation in the AA genotype group of the promoter region C2549A of the leptin gene significantly higher. The A allele of promoter region C2549A of the leptin gene may result in the activation of the platelet.