CSF biomarker and PIB-PET-derived beta-amyloid signature predicts metabolic, gray matter, and cognitive changes in nondemented subjects.
Beta-amyloid (Aβ) is a histopathological hallmark of Alzheimer's disease dementia, but high levels of Aβ in the brain can also be found in a substantial proportion of nondemented subjects. Here we investigated which 2-year rate of brain and cognitive changes are present in nondemented subjects with high and low Aβ levels, as assessed with cerebrospinal fluid and molecular positron emission tomography (PET)-based biomarkers of Aβ. In subjects with mild cognitive impairment, increased brain Aβ levels were associated with significantly faster cognitive decline, progression of gray matter atrophy within temporal and parietal brain regions, and a trend for a faster decline in parietal Fludeoxyglucose (FDG)-PET metabolism. Changes in gray matter and FDG-PET mediated the association between Aβ and cognitive decline. In contrast, elderly cognitively healthy controls (HC) with high Aβ levels showed only a faster medial temporal lobe and precuneus volume decline compared with HC with low Aβ. In conclusion, the current results suggest not only that both functional and volumetric brain changes are associated with high Aβ years before the onset of dementia but also that HC with substantial Aβ levels show higher Aβ pathology resistance, lack other pathologies that condition neurotoxic effects of Aβ, or accumulated Aβ for a shorter time period.
Department of Radiology, University of California, San Francisco, 94143, USA. michael.ewers@ucsf.edu
Michael
M
Ewers
Philip
P
Insel
William J
WJ
Jagust
Leslie
L
Shaw
John Q
JQ
Trojanowski
Paul
P
Aisen
Ronald C
RC
Petersen
Norbert
N
Schuff
Michael W
MW
Weiner
D000368:Aged; D000369:Aged, 80 and over; D016229:Amyloid beta-Peptides / Q000032:analysis / Q000134:cerebrospinal fluid*; D000814:Aniline Compounds; D015415:Biomarkers / Q000032:analysis / Q000134:cerebrospinal fluid*; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology*; D060825:Cognitive Dysfunction / Q000134:cerebrospinal fluid / Q000000981:diagnostic imaging / Q000473:pathology; D042241:Early Diagnosis; D006801:Humans; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D013844:Thiazoles
C475519:2-(4'-(methylamino)phenyl)-6-hydroxybenzothiazole; D016229:Amyloid beta-Peptides; D000814:Aniline Compounds; D015415:Biomarkers; D019275:Radiopharmaceuticals; D013844:Thiazoles