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Vascular alterations in PDAPP mice after anti‐Aβ immunotherapy: Implications for amyloid‐related imaging abnormalities
Author(s) -
Zago Wagner,
Schroeter Sally,
Guido Teresa,
Khan Karen,
Seubert Peter,
Yednock Ted,
Schenk Dale,
Gregg Keith M.,
Games Dora,
Bard Frédérique,
Kinney Gene G.
Publication year - 2013
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2012.11.010
Subject(s) - pathology , medicine , vascular permeability , immunotherapy , context (archaeology) , vascular disease , positron emission tomography , antibody , immunology , immune system , biology , nuclear medicine , paleontology
Background Clinical studies of β‐amyloid (Aβ) immunotherapy in Alzheimer's disease (AD) patients have demonstrated reduction of central Aβ plaque by positron emission tomography (PET) imaging and the appearance of amyloid‐related imaging abnormalities (ARIA). To better understand the relationship between ARIA and the pathophysiology of AD, we undertook a series of studies in PDAPP mice evaluating vascular alterations in the context of central Aβ pathology and after anti‐Aβ immunotherapy. Methods We analyzed PDAPP mice treated with either 3 mg/kg/week of 3D6, the murine form of bapineuzumab, or isotype control antibodies for periods ranging from 1 to 36 weeks and evaluated the vascular alterations in the context of Aβ pathology and after anti‐Aβ immunotherapy. The number of mice in each treatment group ranged from 26 to 39 and a total of 345 animals were analyzed. Results The central vasculature displayed morphological abnormalities associated with vascular Aβ deposits. Treatment with 3D6 antibody induced clearance of vascular Aβ that was spatially and temporally associated with a transient increase in microhemorrhage and in capillary Aβ deposition. Microhemorrhage resolved over a time period that was associated with a recovery of vascular morphology and a decrease in capillary Aβ accumulation. Conclusions These data suggest that vascular leakage events, such as microhemorrhage, may be related to the removal of vascular Aβ. With continued treatment, this initial susceptibility period is followed by restoration of vascular morphology and reduced vulnerability to further vascular leakage events. The data collectively suggested a vascular amyloid clearance model of ARIA, which accounts for the currently known risk factors for the incidence of ARIA in clinical studies.