title: Platelets in the Alzheimer's disease brain: do they play a role in cerebral amyloid angiopathy?
abstract: Alzheimer's disease (AD) is characterized by extracellular beta-amyloid plaques and intracellular tau tangles. AD-related pathology is often accompanied by vascular changes. The predominant vascular lesions in AD are cerebral amyloid angiopathy (CAA) and arteriosclerosis. Platelets circulate along the vessel wall responding immediately to vascular injury. The aim of the present study was to explore the presence and migration of platelets (thrombocytes) to sites of small vascular bleedings and/or to beta-amyloid plaques in the brain. We infused fluorescently labeled red PKH26 mouse platelets into transgenic Alzheimer mice overexpressing APP with Swedish/Dutch/Iowa mutations (APP_SDI) and explored if platelets migrate into the brain. Further we studied whether platelets accumulate in the vicinity of β-amyloid plaques. Our animal data shows that infused platelets are found in the liver and partly in the lung, while in the brain platelets were visible to a minor degree. In mice, we did not observe a significant association of platelets with beta-amyloid plaques or vessels. In the brain of Alzheimer postmortem patients platelets could be detected by immunohistochemistry for CD41 and CD62P, but the majority was found in vessels with or without beta-amyloid load, and only a few single platelets migrated deeper into the brain. Our findings suggest that platelets do not migrate into the brains of Alzheimer disease but are concentrated in brain vessels.
authors.forename: Kathrin M
authors.initials: KM
authors.lastname: Kniewallner
authors.forename: Daniela
authors.initials: D
authors.lastname: Ehrlich
authors.forename: Andreas
authors.initials: A
authors.lastname: Kiefer
authors.forename: Josef
authors.initials: J
authors.lastname: Marksteiner
authors.affiliation: Deparment of Psychiatry and Psychotherapy, Anichstr. 35, A-6020 Innsbruck, Austria. christian.humpel@i-med.ac.at.
authors.forename: Christian
authors.initials: C
authors.lastname: Humpel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000235:genetics / Q000473:pathology*; D016564:Amyloid beta-Protein Precursor / Q000235:genetics; D000818:Animals; D001792:Blood Platelets / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D016657:Cerebral Amyloid Angiopathy / Q000175:diagnosis / Q000473:pathology*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics; D004195:Disease Models, Animal; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009930:Organic Chemicals / Q000378:metabolism; D019007:P-Selectin / Q000378:metabolism; D040201:Platelet Membrane Glycoprotein IIb / Q000378:metabolism
chemical_list: D016564:Amyloid beta-Protein Precursor; C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D009930:Organic Chemicals; D019007:P-Selectin; C070080:PKH 26; D040201:Platelet Membrane Glycoprotein IIb