Amyloid and Tau Pathology are Associated with Cerebral Blood Flow in a Mixed Sample of Nondemented Older Adults with and without Vascular Risk Factors for Alzheimer’s Disease

Abstract

Alzheimer's disease (AD) is the leading cause of dementia in individuals over 65 in the U.S. Prevalence is projected to double by 2050, but current treatments cannot stop the progression of AD. Treatments administered before severe cognitive decline may be effective; identification of biomarkers for preclinical/prodromal stages of AD is therefore imperative. Cerebral blood flow (CBF) is a potential early biomarker for AD; generally, older adults with AD have decreased CBF compared to normally aging peers. Characterization should include the relationship between CBF and AD risk factors and pathologies. We assessed the relationships between CBF quantified by arterial spin labeled MRI, hypertension, APOE ε4, and amyloid and tau PET in 78 older adults: cognitively normal, subjective cognitive decline, and mild cognitive impairment. Decreased regional CBF was associated with increased tau pathology, and the relationship between CBF and amyloid pathology differed by hypertension status. Our findings suggest a complex relationship between risk factors, AD pathologies, and CBF that warrants future studies of CBF as a potential early biomarker for AD.