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Novel Mechanism for Buffering Dietary Salt in Humans: Effects of Salt Loading on Skin Sodium, Vascular Endothelial Growth Factor C, and Blood Pressure.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Selvarajah, Viknesh 
Mäki-Petäjä, Kaisa M 
Pedro, Liliana 
Bruggraber, Sylvaine FA 
Burling, Keith 

Abstract

High dietary sodium intake triggers increased blood pressure (BP). Animal studies show that dietary salt loading results in dermal Na+ accumulation and lymphangiogenesis mediated by VEGF-C (vascular endothelial growth factor C), both attenuating the rise in BP. Our objective was to determine whether these mechanisms function in humans. We assessed skin electrolytes, BP, and plasma VEGF-C in 48 healthy participants randomized to placebo (70 mmol sodium/d) and slow sodium (200 mmol/d) for 7 days. Skin Na+ and K+ concentrations were measured in mg/g of wet tissue and expressed as the ratio Na+:K+ to correct for variability in sample hydration. Skin Na+:K+ increased between placebo and slow sodium phases (2.91±0.08 versus 3.12±0.09; P=0.01). In post hoc analysis, there was a suggestion of a sex-specific effect, with a significant increase in skin Na+:K+ in men (2.59±0.09 versus 2.88±0.12; P=0.008) but not women (3.23±0.10 versus 3.36±0.12; P=0.31). Women showed a significant increase in 24-hour mean BP with salt loading (93±1 versus 91±1 mm Hg; P<0.001) while men did not (96±2 versus 96±2 mm Hg; P=0.91). Skin Na+:K+ correlated with BP, stroke volume, and peripheral vascular resistance in men but not in women. No change was noted in plasma VEGF-C. These findings suggest that the skin may buffer dietary Na+, reducing the hemodynamic consequences of increased salt, and this may be influenced by sex.

Description

Keywords

blood pressure, skin, sodium, stroke volume, vascular endothelial growth factor C, Adult, Blood Pressure, Diet, Sodium-Restricted, Double-Blind Method, England, Female, Hemodynamics, Humans, Hypertension, Male, Middle Aged, Potassium, Renal Elimination, Sex Factors, Skin, Sodium, Sodium Chloride, Vascular Endothelial Growth Factor C, Water-Electrolyte Balance

Journal Title

Hypertension

Conference Name

Journal ISSN

0194-911X
1524-4563

Volume Title

70

Publisher

Sponsorship
British Heart Foundation (None)
Department of Health (via National Institute for Health Research (NIHR)) (NF-SI-0515-10093)
NIHR Clinical Research Network Eastern (via Cambridge University Hospitals NHS Foundation Trust (CUH)) (CRN 2017/18)