Association of a 5178C→A (Leu237Met) polymorphism in the mitochondrial DNA with a low prevalence of myocardial infarction in Japanese individuals

Because mitochondria are the major sources of reactive oxygen species (ROS) in cells, certain alterations in mitochondrial functions can lead to metabolic perturbation in vascular endothelial cells and smooth muscle cells, resulting in vascular dysfunction. We previously demonstrated that a C→A transversion in mitochondrial DNA (mtDNA) at nucleotide 5178 of the NADH dehydrogenase subunit 2 (ND2) gene, which results in a Leu→Met substitution at amino acid 237, was found more frequently in Japanese centenarians than in controls. We also demonstrated that this Mt5178C→A polymorphism has anti-atherosclerotic effects in diabetic subjects. We have now examined whether the Mt5178C→A (Leu237Met) polymorphism in the mitochondrial ND2 gene is associated with a low prevalence of myocardial infarction (MI) in a case-control study. The genotype of ND2 gene was determined either with a polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) or a colorimetry-based allele-specific DNA probe assay. Multivariate logistic regression analysis with adjustment for age, gender, body mass index, smoking status, hypertension, diabetes mellitus, hypercholesterolemia, and hyperuricemia revealed that the frequency of the Mt5178A genotype was significantly higher in controls than in subjects with MI. These results suggest that the 5178A genotype of mitochondrial ND2 gene polymorphism is protective against MI; and this effect would explain, at least in part, its contribution to longevity.