engleski

ACUTE HIGH SALT INTAKE IS ASSOCIATED WITH IMPAIRED MICRO- AND MACROVASCULAR REACTIVITY IN YOUNG HEALTHY INDIVIDUALS

Objective The aim of our study was to elucidate the effect of acute salt loading on vascular function in both micro- and macrocirculation by using in vivo and in vitro methods in young healthy individuals. Design and Methods Young healthy women were subjected to HS diet (intake of 11.2 g of salt/day) for 7 days. Blood pressure (BP) and heart rate, just as plasma renin activity (PRA), plasma aldosterone and both plasma and 24h urine sodium, potassium, urea and creatinine levels were measured before and after diet protocol. Microvascular reactivity of forearm skin microcirculation was assessed by laser Doppler flowmetry (LDF). Brachial artery flow-mediated dilation (FMD) and nitroglycerin (NTG ; 0.4 mg) dilation were measured with ultrasound imaging. Pulse wave velocity (PWV) was determined using a semiautomatic device. In one group of participants subcutaneous fat tissue biopsies were obtained and resistance arteries from biopsies were cannulated for vascular reactivity measurements in response to flow (FID ; pressure gradient Δ10-Δ100cmH2O) and in response to acetylcholine (AChID ; ACh 10-9-10- 4 M). Results Changes in 24h urinary sodium, PRA and plasma aldosterone levels confirmed subjects conformed to the diet guidelines. There was no change in BP and PWV before and after HS diet protocol. HS diet caused significant impairment in forearm skin microvascular reactivity. Brachial artery FMD was reduced after HS diet and endothelium- independent responses to NTG were similar before and after HS diet. While HS diet did not change baseline FID and AchID of isolated resistance arteries, the mechanisms of endothelium dependent dilation were significantly modified by HS diet protocol. Conclusions One week of acute HS loading: 1) significantly impairs in vivo measured both microvascular and macrovascular reactivity without change in BP and arterial stiffnes and 2) changes mechanisms of endothelium dependent vasodilation of isolated resistance arteries in young healthy individuals.

high salt diet; laser doppler flowmetry; flow mediated dilation

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