It is well accepted that high-salt (HS) intake is an essential risk factor in development and progression of hypertension. Results of some recent studies suggest that some of the deleterious effects of a HS diet are independent of elevated blood pressure (BP) and may occur in normotensive individuals and are associated with impaired endothelial function. However, the effects of acute salt loading on endothelial function and vascular reactivity in young healthy individuals are still scarce and inconsistent. The purpose of present study is to determine whether one week of HS intake affects microvascular reactivity in young healthy subjects without changes in BP. In addition, the investigators sought to evaluate if potential HS diet-induced microvascular dysfunction is associated with changes in oxidative stress level and/or with modification of immunological response in young healthy subjects.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
50
Intake of less than 2.3 g of salt per day for 7 days.
Intake of 11.2 g of salt per day for 7 days.
Faculty of Medicine Osijek, Laboratory for Clinical and Sport Physiology
Osijek, Croatia
RECRUITINGmicrovascular reactivity
Cutaneous microvascular blood flow will be measured by Laser Doppler Flowmetry in response to vascular occlusion (post occlusive reactive hyperemia- PORH) and in response to iontophoresis of acetylcholine (ACh) (endothelium dependent vasodilation) before and after diet protocols.
Time frame: two weeks after starting the protocol
oxidative stress
As direct indicator of oxidative stress, byproducts of lipid peroxidation - TBARS method (Thiobarbituric Acid Reactive Substances) with malondialdehyde (MDA) as standard (µM MDA) will be measured before and after LS and HS diet protocol (spectrophotometric method).
Time frame: two weeks after starting the protocol
modification of immunological response by high salt diet
Activated monocytes/macrophages and neutrophils will be measured by flow cytometry, with distinction of subpopulation of monocytes/macrophages (classical/nonclassical), their activation and the expression of the integrin LFA-1 (lymphocyte function-associated antigen 1) and VLA-4 (Very Late Antigen-4) - ligands VCAM-1 (vascular cell adhesion molecule 1 ) and ICAM-1 (vascular cell adhesion molecule 1).
Time frame: two weeks after starting the protocol
antioxidant capacity
As an indicator of antioxidant capacity, the ferric reducing ability of plasma - the FRAP assay (Ferric reducing ability of plasma) with Trolox used as standard (mM Trolox) will be measured before and after LS and HS diet protocol (spectrophotometric method).
Time frame: two weeks after starting the protocol
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