title: Interleukin-1 expression in different plaque types in Alzheimer's disease: significance in plaque evolution.
abstract: The histologically apparent polymorphism of plaques containing beta-amyloid in Alzheimer's disease is thought to represent different stages in plaque evolution. beta-amyloid-immunopositive plaques were classified according to the pattern of beta-amyloid distribution (diffuse vs dense-core) and the presence or absence of dystrophic beta-amyloid precursor protein-immunopositive (beta-APP+) neurites (neuritic vs non-neuritic). The potential contribution of microglia-derived interleukin-1 (IL-1), an immune response cytokine that induces synthesis and processing of beta-APP, to the possible sequential development of these plaque types was examined through determination of the number of IL-1 alpha+ microglia associated with each of four identified plaque types. Diffuse non-neuritic plaques had the least dense and most widely dispersed beta-amyloid, did not exhibit beta-APP+ dystrophic neurites, but most (78%) contained activated IL-1 alpha+ microglia (2 +/- 0.2/plaque; mean +/- SEM). Diffuse neuritic plaques had more dense, but still widely dispersed beta-amyloid, displayed a profusion of beta-APP+ dystrophic neurites, and had the greatest numbers of associated activated IL-1 alpha+ microglia (7 +/- 0.8/plaque). Dense-core neuritic plaques had both compact and diffuse beta-amyloid and had fewer IL-1 alpha+ microglia (4 +/- 0.4/plaque). Dense-core, non-neuritic plaques had compact beta-amyloid, lacked associated diffuse beta-amyloid, and were devoid of both IL-1 alpha+ microglia and beta-APP+ dystrophic neurites. These results suggest an important immunological component in the evolution of amyloid-containing plaques in Alzheimer's disease and further suggest that IL-1-expressing cells are necessary to initiate dystrophic neurite formation in diffuse beta-amyloid deposits.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Arkansas Children's Hospital Research Center, Little Rock 72202-3591.
authors.forename: W S
authors.initials: WS
authors.lastname: Griffin
authors.forename: J G
authors.initials: JG
authors.lastname: Sheng
authors.forename: G W
authors.initials: GW
authors.lastname: Roberts
authors.forename: R E
authors.initials: RE
authors.lastname: Mrak
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000276:immunology / Q000473:pathology*; D001344:Autopsy; D006801:Humans; D007150:Immunohistochemistry; D007375:Interleukin-1 / Q000032:analysis*; D008875:Middle Aged; D013702:Temporal Lobe / Q000276:immunology / Q000473:pathology*
chemical_list: D007375:Interleukin-1