Aterosclerose: Análise do polimorfismo T786C do gene eNOS.

Abstract

Coronary artery disease (CAD) is the most common form of cardiovascular disease. CAD is a multifactorial disease of complex etiology, influenced by genetic and environmental determinants. Atherosclerotic lesion is the most common abnormality found in the arteries resulting from two basic processes: cholesterol accumulation and the proliferation of smooth muscle cells in the tunica intima, thus developing on a substrate formed of these cells, leukocytes derived from blood and a variable amount of connective tissue forming a fibrous plaque that projects into the lumen modifying the middle tunica and leading to a series of circulatory complications. Nitric oxide (NO) produced by nitric oxide endothelial synthase (eNOS) is known to alter blood flow, altering processes involved in atherosclerosis, and is considered an important atheroprotective. One of the polymorphisms most studied is a SNP in the promoter region (T786C), often associated with the development of coronary disease. T786C is an important thymine to cytosine point mutation at codon-786 in the 50-flanking region of the eNOS gene, which could significantly reduce the activity of the gene promoter and serum nitric oxide level. This polymorphism significantly reduces the activity of the eNOS promoter gene. We collected 297 peripheral blood samples, from patients referred to the cardiology service and peripheral vascular surgery, of the Angiogyn Clinic in the city of Goiânia, with previous diagnosis of atherosclerotic disease based on clinical examination and confirmed by imaging methods (197 samples) and control group (100 samples). The collected samples were submitted to PCR to verify presence of polymorphisms. The results were compared using the Chi-Square test and Test G, with the aid of Bioestat software (version 5.3; biocistron.blogspot.com/). In the present study the frequency of the TC genotype was more frequent. In the control group, the higher frequency was observed in the TC genotype. This difference was not statistically significant. Making a relation between the TC/TT and CC genotypes in the case group; TC/TT and CC in the control group, we found that this difference is also not significant. No significant difference was found when genotypes (TT, TC and CC) were analyzed, associated with gender and smoking. The results were not significant because a traditional standard was used, where there is usually twice as many cases for the number of controls, and also because atherosclerosis is a very common disease. Several studies have indicated that when the n worked is double the control in relation to the number of cases, this would lead to a better epidemiological statistic. We can also conclude that there is a strong tendency of the T allele, in single dose or double dose, in association with atherosclerosis.