Associations of rDNA copy numbers and global DNA methylation with myocardial infarction

Alterations in ribosomal DNA copy number (rDNA-CN) and global DNA methylation have been associated with genomic instability and various diseases. However, their relevance in myocardial infarction (MI) has not been fully investigated.

We measured rDNA-CN and global DNA methylation in blood samples from MI patients (n = 100) and healthy controls (n = 109) using Droplet Digital PCR (ddPCR) and ELISA, respectively. Logistic regression was used to assess associations with MI, before and after adjustment for age and sex. Correlations of rDNA CN and global DNA methylation with age were also evaluated. Discriminatory performance was assessed using receiver operating characteristic (ROC) curve analysis.

rDNA-CN was associated with MI in the unadjusted analysis (OR=0.991, p < 0.001), but the effect was no longer significant after adjusting for age and sex (OR=0.992, p = 0.06). In contrast, global DNA methylation remained significantly associated with MI after adjustment (OR=1.61, p < 0.001). Global DNA methylation also demonstrated strong discriminative ability for MI (AUC = 0.97).

Global DNA methylation was independently associated with MI after the adjustments, whereas rDNA-CN was not. These findings suggest that global DNA methylation may represent a potential biomarker; however, further validation in larger, well-characterized populations is warranted.