Heme-a the heme prosthetic group of cytochrome c oxidase is increased in Alzheimer’s disease

摘要

Heme-a, is the heme prosthetic group of cytochrome c oxidase (COX), the terminal complex of the mitochondrial electron transport chain. We measured heme-a levels in postmortem brain tissue from nine patients diagnosed with dementia: Alzheimer’s disease (AD) was the primary diagnosis in five, AD/Diffuse Lewy body disease (DLBD) was diagnosed in two, DLBD was diagnosed in one, and DLBD (severe)/AD (mild) was diagnosed in one. Eight non-demented patients who died from non-neurological causes served as controls. When the primary diagnosis was AD (AD and AD/DLBD), levels of cerebral heme-a were increased almost two-fold on a protein basis compared to controls (p<0.001). Using perfused and unperfused rats we showed that measured levels of cerebral heme-a were unaffected by the presence of blood in brain tissue. In mice we showed that levels of cerebral heme-a were unaffected by 24 hours of storage at 4°C prior to freezing. These animal studies suggest that increased levels of cerebral heme-a in AD were not due to blood in postmortem brain or variation in postmortem interval.