Significant Association Between Low Mitochondrial DNA Content in Peripheral Blood Leukocytes and Ischemic Stroke

BACKGROUND Cumulative evidence has shown that low mitochondrial DNA (mtDNA) content is related to elevated oxidative stress and atherosclerosis, which play important roles in ischemic stroke. The objective of this study was to explore the association between mtDNA content in peripheral blood leukocytes and ischemic stroke. METHODS AND RESULTS A total of 350 patients with first-ever ischemic stroke and 350 healthy controls were recruited in this case-control study. The mtDNA content in peripheral blood leukocytes was determined by quantitative real-time polymerase chain reaction. The levels of oxidized glutathione, reduced glutathione, and 8-hydroxy-2'-deoxyguanosine were measured by ELISA kits. Multivariate logistic regression models were used to analyze the relationship between mtDNA content in peripheral blood leukocytes and ischemic stroke. Our results show that mtDNA content of patients with ischemic stroke was notably lower compared with controls. A significant association was found between low mtDNA content and ischemic stroke. Furthermore, significant interactions were identified between low mtDNA and proven risk factors in patients with ischemic stroke. The levels of oxidized glutathione and 8-hydroxy-2'-deoxyguanosine were significantly greater in patients with ischemic stroke compared with controls. CONCLUSIONS Our results demonstrate that low mtDNA content in peripheral blood leukocytes is associated with ischemic stroke. The relationship of low mtDNA content and ischemic stroke was particularly notable in individuals who had low mtDNA content combined with diabetes mellitus, metabolic syndrome, or cigarette smoking. Oxidative stress may be one of the contributory factors to decreased mtDNA content in patients with ischemic stroke.