Blood Pressure Level Is Associated With Changes In Plasma A Beta(1-40) And A Beta(1-42) Levels: A Cross-Sectional Study Conducted In The Suburbs Of Xi'An, China

Objectives: Amyloid-beta (A beta) deposition in the brain is the hallmark of Alzheimer's disease (AD) pathology. Hypertension is a risk factor for AD, but the effects of hypertension on A beta deposition are not fully determined. Considering peripheral A beta closely relates to A beta deposition in the brain, we investigated the relationships between blood pressure (BP) level and plasma A beta concentrations.Methods: One-thousand and sixty-nine participants (age above 45) from a village in the suburbs of Xi'an, China were enrolled. Questionnaires and validated Chinese versions of the Mini-Mental State Examination (MMSE) were used to collect information about vascular risk factors and assess cognition function. The apolipoprotein E (ApoE) genotype was detected using PCR and sequencing. Plasma A beta levels were measured using ELISA. The associations between BP and plasma A beta levels were analyzed by using multivariate linear regression.Results: Plasma A beta(1-40) level was higher in high BP group than that in normal BP group (53.34 +/- 8.50 pg/ml vs. 51.98 +/- 8.96 pg/ml, P = 0.013), in high SBP group than that in normal SBP group (53.68 +/- 8.69 pg/ml vs. 51.88 +/- 8.80 pg/ml, P = 0.001) and in high MABP group than that in normal MABP group (54.05 +/- 8.78 pg/ml vs. 52.04 +/- 8.75 pg/ml, P = 0.001). After controlling for the confounding factors, SBP (b = 0.078, P < 0.001), DBP (b = 0.090, P = 0.008) and MABP (b = 0.104, P < 0.001) correlated with plasma A beta(1-40) level positively in ApoE epsilon 4 non-carriers, but not ApoE epsilon 4 carriers.Conclusions: Elevated BP levels were associated with increased plasma A beta(1-40) levels in middle-aged and elderly ApoE epsilon 4 non-carriers.