Microglia, amyloid and dementia in Alzheimer disease - A correlative study

To elucidate the role of microglia in Alzheimer's disease, a clinicopathological study was performed involving 26 cases, the mental status of which had been studied pre mortem by the Blessed test score (BTS). We measured the volume density of CD 68 immunoreactive (IR) microglia, congophilic plaques and AP deposits, and the numerical density of neurofibrillary tangles (NFT) in a sample of Area 9 (middle frontal gyrus). Dementia was significantly correlated only with the volume density of A beta deposits and the numerical density of NFT. The volume densities of microglia and congophilic plaques were strongly correlated. With the intellectual status used as a time scale, IR microglia and amyloid deposits appealed almost simultaneously at an early stage in the pathological cascade and decreased, whereas A beta and NFT were still accumulating. The intellectual deficit seemed to be more significantly related to the latter two lesions than to the microglia-amyloid complex, that was visible at an earlier stage (around BTS = 15). (C) 2000 Elsevier Science Inc. All rights reserved.