Molecular analysis of the estrogen receptor alpha gene in men with coronary artery disease: association with disease status

Background : The vasoprotective effects of estrogens are known to be mediated by their respective estrogen receptors (ER) alpha (ERα) and beta (ERβ), which are present on the vascular wall. The amino-terminal part of the ERα appears to be important; genetic alterations in this region have been associated with arterial hypertension. This region has not been studied in atherosclerotic disease. In the present study, we examined the association between coronary artery disease (CAD) and alterations of the NH 2 -terminal part of ERα coding region. Methods : Genomic DNA was isolated from 50 healthy men and 40 men with CAD confirmed by coronary angiography. The coding sequences of exons 1 and 2 were amplified by polymerase chain reaction (PCR) and analyzed by either denaturing gradient gel electrophoresis (DGGE) or single stranded conformational polymorphism (SSCP), or both, sequencing and restriction fragment length polymorphism (RFLP), as appropriate. In the same subjects, biochemical and vascular parameters were also determined by using the appropriate methodology. Results : In exon 1, the codon 10 polymorphism was detected in both patients and healthy men either in heterozygous or homozygous form. The codon 87 polymorphism was detected mainly in homozygous form and only five individuals were heterozygotes. No mutations were found in exon 2. Statistical analysis of the allele distribution for either codon 10 or 87 between patients and healthy men showed no significant difference. In patients, the biochemical parameters were not statistically significantly different between ERα codon 10 genotypes or alleles. However, there was a clear effect of the TCT/TCT genotype and TCT allele on the vascular parameters whereas the right internal carotid artery (RICA) intima-media thickness was significantly associated with TCT/TCT genotype and TCT allele. Conclusions : We conclude that ERα genotypes play no role in the incidence of CAD disease, however, ERα codon 10 may be a genetic factor controlling some vessels' angiographic complications.