Cerebrovascular stiffness and flow dynamics in the presence of amyloid and tau biomarkers

INTRODUCTION: This work investigated the relationship between cerebrovascular disease (CVD) markers and Alzheimer's disease (AD) biomarkers of amyloid beta deposition, and neurofibrillary tau tangles in subjects spanning the AD clinical spectrum. METHODS: A total of 136 subjects participated in this study. Four groups were established based on AD biomarker positivity from positron emission tomography (amyloid [A] and tau [T]) and clinical diagnosis (cognitively normal [CN] and impaired [IM]). CVD markers were derived from structural and quantitative magnetic resonance imaging data. RESULTS: Transcapillary pulse wave delay was significantly longer in controls compared to AT biomarker–confirmed groups (A+/T–/CN P < .001, A+/T+/CN P < .001, A+/T+/IM P = .003). Intracranial low‐frequency oscillations were diminished in AT biomarker–confirmed groups both CN and impaired (A+/T–/CN P = .039, A+/T+/CN P = .007, A+/T+/IM P = .011). A significantly higher presence of microhemorrhages was measured in A+/T+/CN compared to controls (P = .006). DISCUSSION: Cerebrovascular markers indicate increased vessel stiffness and reduced vasomotion in AT biomarker–positive subjects during preclinical AD.