Mitochondrial abnormalities in Alzheimer brain: mechanistic implications.
Reductions in cerebral metabolism sufficient to impair cognition in normal individuals also occur in Alzheimer's disease (AD). The degree of clinical disability in AD correlates closely to the magnitude of the reduction in brain metabolism. Therefore, we tested whether impairments in tricarboxylic acid (TCA) cycle enzymes of mitochondria correlate with disability. Brains were from patients with autopsy-confirmed AD and clinical dementia ratings (CDRs) before death. Significant (p < 0.01) decreases occurred in the activities of the pyruvate dehydrogenase complex (-41%), isocitrate dehydrogenase (-27%), and the alpha-ketoglutarate dehydrogenase complex (-57%). Activities of succinate dehydrogenase (complex II) (+44%) and malate dehydrogenase (+54%) were increased (p < 0.01). Activities of the other four TCA cycle enzymes were unchanged. All of the changes in TCA cycle activities correlated with the clinical state (p < 0.01), suggesting a coordinated mitochondrial alteration. The highest correlation was with pyruvate dehydrogenase complex (r = 0.77, r2= 0.59). Measures to improve TCA cycle metabolism might benefit AD patients.
Bubber
Parvesh
P
Weill Medical College of Cornell University at Burke Medical Research Institute, White Plains, NY 10605, USA.
Haroutunian
Vahram
V
Fisch
Gene
G
Blass
John P
JP
Gibson
Gary E
GE
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology; D000544:Alzheimer Disease / Q000201:enzymology / Q000473:pathology* / Q000503:physiopathology; D000818:Animals; D001921:Brain / Q000201:enzymology / Q000473:pathology* / Q000503:physiopathology; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D002952:Citric Acid Cycle / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D008928:Mitochondria / Q000201:enzymology / Q000473:pathology*; D058225:Plaque, Amyloid / Q000473:pathology; D011180:Postmortem Changes; D017397:Prefrontal Cortex / Q000201:enzymology / Q000473:pathology; D011569:Psychiatric Status Rating Scales; D011768:Pyruvate Dehydrogenase Complex / Q000378:metabolism
D011768:Pyruvate Dehydrogenase Complex; D002795:Choline O-Acetyltransferase