title: Neurological cholinesterases in the normal brain and in Alzheimer's disease: relationship to plaques, tangles, and patterns of selective vulnerability.
abstract: Butyrylcholinesterase (BChE) and an altered form of acetylcholinesterase (AChE) accumulate in the plaques and tangles of Alzheimer's disease (AD). The sources for these plaque- and tangle-bound cholinesterases have not been identified. We now report that AChE and BChE activities with pH preferences and inhibitor selectivities identical to those of plaque- and tangle-bound cholinesterases are found in the astrocytes and oligodendrocytes of control and AD brains. These glial-type cholinesterases are selectively inhibited by indolamines and protease inhibitors. In control brains glial-type cholinesterases appear confined to the intracellular space, whereas in patients with AD they decorate plaques and tangles as well. In control and AD brains AChE-positive glia are distributed throughout the cortical layers and subcortical white matter, whereas BChE-positive glia reach high densities only in the deep cortical layers and white matter. In non-AD control brains, the ratio of BChE to AChE glia was higher in entorhinal and inferotemporal cortex, two regions with a high susceptibility to the pathology of AD, than in primary somatosensory and visual cortex, two areas with a relatively lower susceptibility to the disease process. There was no age-related differences in the density or distribution of cholinesterase-positive glia. In comparison with age-matched control specimens, AD brains had a significantly higher density of BChE glia and a lower density of AChE glia in entorhinal and inferotemporal regions but not in the primary somatosensory or visual areas. These results suggest that glia constitute a likely source for the cholinesterase activity of plaques and tangles and that a high ratio of BChE- to AChE-positive glia may play a permissive or causative role in the neuropathology of AD.
authors.affiliation: Bullard and Denny-Brown Laboratories, Department of Neurology, Beth Israel Hospital, Boston, MA 02215.
authors.forename: C I
authors.initials: CI
authors.lastname: Wright
authors.forename: C
authors.initials: C
authors.lastname: Geula
authors.forename: M M
authors.initials: MM
authors.lastname: Mesulam
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis / Q000378:metabolism*; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000201:enzymology* / Q000473:pathology*; D001921:Brain / Q000201:enzymology* / Q000473:pathology*; D002091:Butyrylcholinesterase / Q000032:analysis / Q000378:metabolism*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016874:Neurofibrillary Tangles / Q000201:enzymology* / Q000473:pathology; D009457:Neuroglia / Q000201:enzymology* / Q000473:pathology; D012016:Reference Values
chemical_list: D002800:Cholinesterase Inhibitors; D000110:Acetylcholinesterase; D002091:Butyrylcholinesterase