engleski

7-day Salt Loading Impairs Microvascular Endothelium-Dependent Vasodilation Without Changes in Blood Pressure, Body Composition and Fluid Status in Healthy Young Humans

Objectives: We aimed to assess whether a 7-day high-salt (HS) diet affects endothelium- dependent and/or endothelium-independent microvascular function in the absence of changes in arterial blood pressure, and to determine whether such microvascular changes are associated with changes in body composition and fluid status in healthy young humans. Materials and Methods: Fifty-three young healthy individuals (twenty-eight women and twenty-five men) were assigned to a 7-day low- salt (LS) diet (<3.5 g salt/day) followed by a 7-day HS diet (~14 g salt/day). Skin microvascular blood flow in response to iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) was assessed by laser Doppler flowmetry, and blood pressure (BP), heart rate (HR), plasma renin activity (PRA), serum aldosterone, serum and 24h-urine sodium, potassium, urea and creatinine levels, together with body composition and fluid status measurement with a four-terminal portable impedance analyzer were measured before and after diet protocols. Results: BP, HR, body composition and fluid status were unchanged, and PRA and serum aldosterone level were significantly suppressed after HS diet. ACh- induced dilation (AChID) was significantly impaired, while SNP-induced dilation (SNPID) was not affected by HS diet. Impaired AChID and increased salt intake, as well as impaired AChID and suppressed renin- angiotensin system were significantly positively correlated. Changes in body composition and fluid status parameters were not associated with impaired AChID. Conclusion: 7-day HS diet impairs microvascular reactivity by affecting its endothelium- dependent vasodilation in young healthy individuals. Changes are independent of BP, body composition changes or fluid retention, but are the consequences of the unique effect of HS on endothelial function.

high-salt diet ; microcirculation ; endothelium ; body composition ; renin-angiotensin system

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