The changes of arterial elasticity in normotensive salt sensitive subjects under salt-loading

Abstract

Background Salt sensitivity is implicated as a risk factor for cardiovascular disease. We hypothesized that salt loading would influence the arterial elasticity which could reflect endothelium function. The aim of the study was to investigate the different changes of arterial elasticity under high salt dietary intervention between salt sensitive subjects and non-salt sensitive subjects. Methods A 7-day low-sodium (51.3 mmol sodium/day) followed by a 7-day high-sodium (307.8 mmol sodium/day) dietary intervention was conducted among 31 normotensive subjects. BP measurements were obtained at a baseline examination and following the low-sodium and high-sodium interventions using a random-zero sphygmomanometer. Salt sensitivity was defined as the absolute changes in mean arterial pressure (MAP) from baseline to low-sodium and high-sodium interventions. The arterial elasticity was determined by CVProfilor DO-2020 and expressed as elasticity indexes (C(1)—large artery and C(2)—small artery). Results There were 10 subjects recognized as salt sensitive. During low salt intervention, there were no differences in BP and in large and small arterial elasticity indices between salt sensitive subjects and non-salt sensitive subjects (C1: 14.3±1.17 (SS) vs 14.4±0.81 (NSS); C2: 5.2±0.7 (SS) vs 5.4±0.7 (NSS)). After the 7-day high-sodium dietary intervention, the changes of large artery elasticity (C(1)) in salt sensitive subjects were significantly reduced (2.45±0.45 (SS) vs 0.87±0.78 (NSS) ml mm Hg (−1)x 10, P=0.004), but the small artery elasticity (C(2)) was not found to have significant changes neither in salt sensitive subjects nor in salt insensitive subjects (4.7±2.4 (SS) vs 5.4±2.1 (NSS) ml mm Hg (−1)x 100, P=0. 41). Conclusions Our study indicates that short-term salt loading could reduce the large artery elasticity in salt sensitive subjects, but not in non-salt sensitive subjects. Further study is needed to confirm that long-term high salt can reduce both arterial elasticities (C1 and C2).