Angiotensin-I-converting enzyme (ACE) insertion/deletion polymorphism in Mexican patients with coronary artery disease. Association with the disease but not with lipid levels

Angiotensin-converting enzyme gene D-allele and the severity of coronary artery disease

Coronary artery disease (CAD) is the first cause of morbidity and mortality worldwide. An important goal is to diagnose patients in early stages, in order to reduce acute cardiovascular events. The angiotensin-converting enzyme (ACE) is an important element for the cardiovascular system, through its actions on hydro-salin balance and vascular tone. ACE polymorphism consists of insertions (I)/deletions (D) and there are 3 genotypes: II, ID, DD. It is speculated that the DD genotype may be a genetic basis for severe CAD, while the II genotype may have a protective effect on the coronary arteries. The present study included 154 patients with acute coronary syndroms admitted to the Institute for Cardiovascular Disease 'George I.M. Georgescu', Iasi. The patients underwent coronary angiography in order to assess the severity of the lesions and the ACE genotypes were determined for each patient. The genotypes were correlated with the severity of the vessel-disease and the exposure to classic risk factors. It was concluded that the D-allele is associated with a greater risk for acute coronary events and severe coronary stenosis, especially when risk genotype and risk phenotype interact.

Relationship between angiotensin II receptor expression and cardiovascular risk factors in Mexican patients with coronary occlusive disease

The density of Angiotensin II (Ang) receptors on tissue surfaces is regulated by multiple hormones, cytokines and metabolic factors and is profoundly affected by various pathological conditions, such as age, diet and environmental conditions. The participation of several cardiovascular risk factors in the regulation of Angiotensin II receptor expression has been incompletely studied. We performed an ex-vivo study with human aortic postsurgical specimens to test the hypothesis that Ang AT1 and AT2 receptor expression in human aortic arteries is associated with the presence of cardiovascular risk factors. We included 31 Mexican patients with coronary artery disease. We evaluated Angiotensin II receptor expression by immunostaining and angiotensin converting enzyme insertion/deletion (ACE I/D) polymorphisms by polymerase chain reaction. AT1 and AT2 receptor expression was increased in the aortic segments from the cardiovascular patients compared with control arteries and in patients with the DD genotype. There was a correlation between increased AT1 receptor expression and the number of cardiovascular risk factors present in the patient. Furthermore, reduction of AT1 expression correlated with the number of drug combinations used in the patients. These correlations were not present with respect to AT2 receptor expression. We suggest that increased AT1 receptor expression is associated with the DD genotype. Thus the presence of several cardiovascular risk factors as well as DD genotype, induce AT1 expression increasing the probability to develop coronary occlusive disease.

An alternative method for genotyping of the ACE I/D polymorphism

The mistyping of the angiotensin I-converting enzyme insertion/deletion (ACE I/D) has been well documented, and new methods have been suggested here to improve the genotyping efficiency. Buccal cell samples were collected from 157 young Caucasians, and genotyped using previously known and newly developed PCR amplification genotyping techniques, as well as PCR-RFLP tests for three single nucleotide polymorphisms (rs4327, rs4341 and rs4343). Inconsistent genotyping results were found when using only the PCR amplification genotyping techniques across repeated attempts (8% to 45%), however, individual SNP genotyping was highly consistent (100%). Two SNPs (rs4341 and rs4343) were in complete LD and SNP rs4327 was in high LD with the ACE I/D. The ACE I/D was in HW equilibrium in the portion of the population with consistent genotyping results, whereas the three SNPs were not in HW equilibrium. The mistyping of ACE I/D by only PCR amplification can be improved using alternative methods.