title: Plasma beta amyloid and impaired CO2-induced cerebral vasomotor reactivity.
abstract: Amyloid beta (Abeta) may disturb cerebral autoregulation by damaging the wall of small cerebral blood vessels and by direct negative vasoactive properties. We assessed whether previous and concurrent plasma Abeta(1-40) and Abeta(1-42) levels were associated with an impaired CO2-induced cerebral vasomotor response. In the longitudinal population-based Rotterdam Study we measured plasma Abeta levels and cerebral vasomotor reactivity to hypercapnia with transcranial Doppler ultrasonography (TCD) in 441 people, aged 60-90 years. We performed age and sex adjusted logistic regression analysis. Plasma Abeta levels assessed on average 6.5-year before TCD were linearly associated with an impaired CO2-induced cerebral vasomotor response (odds ratio 1.48 (95%CI 1.19;1.84) per standard deviation increase in Abeta(1-40), and 1.36 (95%CI 1.09;1.70) per standard deviation increase in Abeta(1-42)). Such an association was not present for Abeta assessed concurrently with the TCD measurement. Persons whose plasma Abeta(1-40) levels had decreased in the 6.5-year period preceding TCD measurements were more likely to have an impaired CO2-induced vasomotor reactivity. Overall our observations are most compatible with plasma Abeta levels representing vascular Abeta deposits years later resulting in impaired CO2-induced vasomotor reactivity.
authors.affiliation: Department of Epidemiology and Biostatistics, Erasmus MC, Erasmus University Medical Center, PO Box 1738, 3000 Rotterdam, The Netherlands.
authors.forename: Ewoud J
authors.initials: EJ
authors.lastname: van Dijk
authors.forename: Niels D
authors.initials: ND
authors.lastname: Prins
authors.forename: Albert
authors.initials: A
authors.lastname: Hofman
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: van Duijn
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Koudstaal
authors.forename: Monique M B
authors.initials: MM
authors.lastname: Breteler
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016229:Amyloid beta-Peptides / Q000097:blood*; D001921:Brain / Q000098:blood supply* / Q000378:metabolism*; D002245:Carbon Dioxide / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D017585:Ultrasonography, Doppler, Transcranial; D014666:Vasomotor System / Q000378:metabolism* / Q000503:physiopathology
chemical_list: D016229:Amyloid beta-Peptides; D002245:Carbon Dioxide