Premature Coronary Artery Disease, Association with Relative Blood Number of Mitochondrial DNA Copies in Mexican Population—Results of GEA Study

Abstract

The mitochondrial DNA copy number (mtDNA-CN) is considered an indirect indicator of the number of mitochondria and of mitochondrial dysfunction; its decrease may indirectly reflect mitochondrial DNA (mtDNA) alterations. A reduction in mtDNA-CN is associated with the development of cardiovascular diseases, including coronary artery disease (CAD). The study evaluates the association of relative blood mtDNA-CN with premature CAD (pCAD) and cardiometabolic factors among Mexican individuals from the GEA (Genetics of Atherosclerotic Disease) Mexican cohort. Relative blood mtDNA-CN was quantified by real-time PCR in 835 patients with pCAD and 896 control subjects (defined as a coronary artery calcium score of zero, assessed by computed tomography). Associations were evaluated using logistic regression (odds ratio [95% confidence interval]) adjusted for potential confounders. Compared with controls, patients with pCAD exhibited significantly lower relative blood mtDNA-CN (5.6 [3.5–9.8] vs. 9.1 [5.1–13.2]. p < 0.001). Similar results were observed in the sex-stratified analysis. Specifically, relative blood mtDNA-CN in women (6.2 [3.8–9.9]) and men (5.5 [3.4–9.7]) with pCAD was lower than that in women (9.5 [6.3–13.7]) and men (8.2 [5.5–12.5]) from the control group (p < 0.001). After adjusting for age, sex, body mass index, smoking status, LDL-cholesterol, type 2 diabetes mellitus, hypertension and physical activity, higher relative blood mtDNA-CN showed a negative association with pCAD (0.903 [0.881–0.927], p = 4.96 × 10−15). This association remained significant in men (0.894 [0.866–0.922], p = 2.90 × 10−12) and women (0.917 [0.876–0.960], p = 2.1 × 10−4). Among patients with pCAD, an inverse correlation was observed between relative blood mtDNA-CN and total abdominal fat (p = 0.001), visceral fat (p = 0.015), and subcutaneous fat (p = 0.004). Overall, our results show that reduced relative blood mtDNA-CN is associated with pCAD, which could be indicative of mitochondrial alterations. Furthermore, the inverse correlation between relative blood mtDNA-CN and total, visceral, and subcutaneous abdominal fat suggests a link between mitochondrial dysfunction and abdominal adiposity in patients with pCAD. These findings support that decreased relative blood mtDNA-CN may serve as a marker associated with the presence of pCAD and for adipose tissue alterations in Mexican women and men.