Is mitochondrial DNA depletion involved in Alzheimer's disease?

Several studies have suggested that mitochondrial metabolism disturbances a nd mitochondrial DNA (mtDNA) abnormalities may contribute to the progressio n of the pathology of Alzheimer's disease (AD). In this study we have inves tigated whether the amount of mtDNA is modified in different brain regions (cerebellum, hippocampus and frontal cortex) of confirmed AD necropsies and in blood of living AD patients. We used a real-time PCR method to analyse the mtDNA relative abundance in brain regions from 12 AD and seven controls and from a group of blood samples (17 living AD patients and 11 controls). MtDNA from blood samples together with hippocampus and cerebellum brain ar eas did not show differences between controls and AD. However, AD patients showed a 28% decrease in the amount of mtDNA in the frontal cortex when com pared to controls for this specific area. Since frontal cortex is a severel y affected region in AD, our results support the hypothesis that mitochondr ial defects may play a role in the pathogenesis of AD.