Quantitative neurohistological features of frontotemporal degeneration

Frontotemporal degeneration (FTD) is a neurodegenerative condition that has been principally associated with frontal lobe dementia. in this study, we compared neuropathological abnormalities in frontal, hippocampal, and calca rine cortices from patients assigned a diagnosis of FTD, normal elderly and Alzheimer's disease (AD). Densities of Nissl-stained neurons and lesions w hich were immunolabeled for tau, beta -amyloid (A beta), alpha- and beta -s ynuclein, ubiquitin, glial fibrillary acidic protein (GFAP) and CD68 antige n were determined using computer assisted, non-biased quantitative microsco py. We found that FTD frontal and hippocampal regions exhibited marked neur on loss, abundant ubiquitin-immunoreactive (ir) dystrophic neurites, GFAP-i r astrocytes, and CD68-ir microglia, while calcarine cortex was spared. No alpha- or beta -synuclein-ir lesions were observed, and neither the density of tau-ir neurofibrillary tangles nor that of A beta -ir plaques in FTD ex ceeded normal controls. In addition, there were no neuropathological differ ences between FTD subjects who presented clinically with a frontal lobe dem entia versus an AD-like dementia. These findings indicate that FTD is a cat egory of neurodegnerative dementias with varying clinical presentations tha t is characterized by the progressive degeneration of select populations of cortical neurons. The molecular neurodegenerative mechanisms that lead to FTD remain to be elucidated. (C) 2000 Elsevier Science Inc. All rights rese rved.