Plasma amyloid precursor protein is decreased in Alzheimer's disease.
Alzheimer's disease is characterized by amyloid deposits whose major protein component is beta A4. beta A4 is a product of the amyloid precursor protein (APP). APP was assayed in partially purified plasma samples from 16 sporadic Alzheimer's disease patients, 12 age-matched controls, 15 Down's syndrome individuals aged 19-36 years and 8 young to middle-aged controls (22-51 years). 14 of the 16 Alzheimer's disease patients had decreased plasma APP when compared with age-matched controls. 14 of the 15 Down's syndrome individuals had similar levels of APP when compared with age-matched and elderly non-demented controls by immunoblotting, whereas one had levels of APP less than controls. Taken together with results from a previous report (Lancet 1992; 340: 453-454), the decreased plasma APP levels mirror the changes observed with cerebrospinal fluid APP levels in Alzheimer's disease.
Martins
R N
RN
University Department of Surgery, Hollywood Repatriation General Hospital, Nedlands, Perth, Australia.
Muir
J
J
Brooks
W S
WS
Creasey
H
H
Montgomery
P
P
Sellers
P
P
Broe
G A
GA
D000328:Adult; D000544:Alzheimer Disease / Q000097:blood / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000097:blood / Q000378:metabolism*; D001792:Blood Platelets / Q000378:metabolism; D015153:Blotting, Western; D001923:Brain Chemistry / Q000502:physiology; D004314:Down Syndrome / Q000097:blood; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008875:Middle Aged
D016564:Amyloid beta-Protein Precursor