Background: STEMI (ST-elevation myocardial infarction) is one of the most severe forms of coronary artery disease, known to significantly contribute to DNA damage. There are very few publications in this field in the literature. In our study, we examined the association between four polymorphisms in repair enzymes (LIG4 Thr9Ile, XRCC6 promoter C-57G, XPA -4A/G, OGG1 Ser326Cys) involved in three distinct DNA repair mechanisms (NHEJ (non-homologous end joining), NER (nucleotide excision repair), and BER (base excision repair), and their impact on the risk of STEMI. Methods & Results: This study involved 185 patients diagnosed with STEMI and included 100 healthy controls. The genotyping of SNPs was conducted through the PCR-RFLP (Polymerase chain reaction-restriction fragment length polymorphism) method for the following variants: XRCC6 (rs2267437), XPA (rs1800975), LIG4 ( rs1805388), and OGG1 (rs1052133). No significant differences were observed in the genotype distributions of the XRCC6 and OGG1 variations between the control and patient groups. On the other hand, our findings indicate that individuals carrying the mutant G allele for XPA polymorphism and the mutant Tallele for LIG4 polymorphism are susceptible to STEMI. Conclusions: Our findings demonstrate the significance of NHEJ and NER DNA repair processes in the pathogenesis of STEMI, as evidenced by the observed relationship between LIG4 and XPA polymorphisms.

Background The role of DNA damage in the progression of coronary artery disease (CAD) is widely recognized. Among the factors that determine the extent of DNA damage, genetic factors may be one of the determining factors in the pathogenesis of CAD. Methods & Results In our research, we investigated the expression levels of BRCA1 and PARP1, which are involved in the DNA repair process, as well as the regulators of gene expression for these molecules, namely miR-21-5p, miR-193b-3p, and miR-484, in lymphocyte samples collected from 55 patients with CAD and 55 healthy controls. The fold changes of BRCA1, PARP1, miR-21-5p, miR-193b-3p and miR-484 expression levels in the patient group, as determined by the 2−ΔΔCT calculation, were found to be 0.353, 0.332, 0.734, 0.876, and 1.231, respectively. In the patient group, a statistically significant negative correlation was observed only between PARP1 and miR-21 (r=-0.66, p=0.0001). ConclusionsThe expression levels in molecules related to the DNA repair systems of CAD patients are clearly related to the pathogenesis of the disease, and considering this situation, measures to be taken would be beneficial.