Stimulated release of the beta-amyloid protein of Alzheimer's disease by normal human platelets.
The circulatory system is a potential source of the beta-amyloid protein (A beta) of ageing and Alzheimer's disease (AD), platelets accounting for the bulk of A beta immunoreactivity detectable in blood. Evidence for the release of A beta by platelets, however, has not been reported. Platelets from normal donors were therefore stimulated with collagen to establish if A beta immunoreactive material is released on activation. For comparison, the release of the platelet monoamines, serotonin (5-HT) adrenaline (Adr) and noradrenaline (NA) was also measured. Like the monoamines, collagen-induced A beta release was concentration-dependent, maximal stimulated release exceeding basal efflux by 184%. Collagen EC50 values for A beta release were similar to those for Adr and NA (3.6 +/- 0.6, 3.4 +/- 0.6 and 3.3 +/- 0.2 microg/ml collagen, respectively) but not 5-HT (9.8 +/- 1.9 microg/ml). These data provide the first evidence that platelets release A beta immunoreactive material on stimulation and may indicate that A beta, Adr and NA reside in the same subcellular compartment.
Smith
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Department of Medicine, University College London Medical School, Sir Jules Thorn Institute, The Middlesex Hospital, UK.
D000328:Adult; D000544:Alzheimer Disease / Q000097:blood*; D016229:Amyloid beta-Peptides / Q000097:blood*; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D003094:Collagen / Q000494:pharmacology*; D004837:Epinephrine / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D012016:Reference Values; D012701:Serotonin / Q000097:blood; D013268:Stimulation, Chemical
D016229:Amyloid beta-Peptides; D012701:Serotonin; D003094:Collagen; D009638:Norepinephrine; D004837:Epinephrine