Synergistic interaction of high blood pressure and cerebral beta-amyloid on tau pathology.

ABSTRACT

BACKGROUND: Hypertension has been associated with Alzheimer's disease (AD) dementia as well as vascular dementia. However, the underlying neuropathological changes that link hypertension to AD remain poorly understood. In our study, we examined the relationships of a history of hypertension and high current blood pressure (BP) with in vivo AD pathologies including ß-amyloid (Aß) and tau and also investigated whether a history of hypertension and current BP respectively affect the association between Aß and tau deposition. METHODS: This cross-sectional study was conducted as part of the Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer's Disease, a prospective cohort study. Cognitively normal older adults who underwent both Aß and tau positron emission tomography (PET) (i.e., [11C]-Pittsburgh compound B and [18F] AV-1451 PET) were selected. History of hypertension and current BP were evaluated and cerebral Aß and tau deposition measured by PET were used as main outcomes. Generalized linear regression models were used to estimate associations. RESULTS: A total of 68 cognitively normal older adults (mean [SD] age, 71.5 [7.4] years; 40 women [59%]) were included in the study. Neither a history of hypertension nor the current BP exhibited a direct association with Aß or tau deposition. However, the synergistic interaction effects of high current systolic (ß, 0.359; SE, 0.141; p = 0.014) and diastolic (ß, 0.696; SE, 0.158; p < 0.001) BP state with Aß deposition on tau deposition were significant, whereas there was no such effect for a history of hypertension (ß, 0.186; SE, 0.152; p = 0.224). CONCLUSIONS: The findings suggest that high current BP, but not a history of hypertension, synergistically modulate the relationship between cerebral Aß and tau deposition in late-life. In terms of AD prevention, the results support the importance of strict BP control in cognitively normal older adults with hypertension.