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

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 beta-amyloid (A beta) and tau and also investigated whether a history of hypertension and current BP respectively affect the association between A beta 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 A beta and tau positron emission tomography (PET) (i.e., [C-11]-Pittsburgh compound B and [F-18] AV-1451 PET) were selected. History of hypertension and current BP were evaluated and cerebral A beta 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 A beta or tau deposition. However, the synergistic interaction effects of high current systolic (beta, 0.359; SE, 0.141; p = 0.014) and diastolic (beta, 0.696; SE, 0.158; p < 0.001) BP state with A beta deposition on tau deposition were significant, whereas there was no such effect for a history of hypertension (beta, 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 A beta 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.

Automated summary

This study found a synergistic interaction between high current blood pressure and beta-amyloid and tau deposition in late-life, but no association with a history of hypertension. This suggests that strict blood pressure control is important for the prevention of Alzheimer's disease in cognitively normal older adults with hypertension.