engleski

Role of oxidative stress in inflammatory response induced by a 7-day high-salt diet in salt- resistant healthy individuals

Objective: Earlier studies of our research group demonstrated that oxidative disbalance has the pivotal role in short-term HS diet-induced impairment of endothelial and microvascular function in healthy individuals. This study aimed to investigate the effect of a 7-day high-salt (HS) diet on systemic inflammatory response in salt-resistant healthy individuals, and to test the specific role of oxidative stress in the observed changes. Methods: 30 young healthy individuals adhered to a 7-day low-salt (LS) diet (3.5 g salt/day) followed by a 7-day high-salt (HS) diet (~14.7 g salt/day) protocol. Biomarkers of oxidative stress and antioxidative defence (TBARS, 8-iso- PGF2α, FRAP), serum pro- and anti-inflammatory cytokines (INFγ, TNF-α, IL-6, IL-9, IL-17A, IL-23, IL-10, IL-21, IL-22, TGF-β1), as well as frequencies of peripheral blood Th17 and regulatory T cells (Treg) were measured before and after 7-day HS diet protocol. Results: Short-term HS diet significantly increased serum level of pro-inflammatory cytokines INF-γ, TNF-α, IL-9 and IL-17A level, but also of anti-inflammatory cytokines IL-10 and TGF- β1. A 7-day HS diet led to an increase in biomarkers of oxidative stress (TBARS and 8-iso- PGF2α), and to a decrease of FRAP, which is a biomarker of plasma antioxidant capacity. Frequencies of Th17 and Treg cells were not significantly changed following the HS diet. However, a negative correlation was found between TBARS, as a marker of oxidative stress, and Treg cells, a specialized subpopulation of anti- inflammatory T cells. Conclusions: The present study provided evidence that acute salt-loading induces changes in the immune status of young healthy individuals, manifested as an initial activation of IL-17- secreting Th17 cells, but also a concomitant anti- inflammatory response, potentially mediated by an IL-10 and TGFβ1-secreting Treg cells. Also, a 7- day HS diet increases oxidative stress and reduces antioxidant capacity. Negative correlation between TBARS and Treg cells frequency, suggests the modulatory role of oxidative stress in inflammatory responses induced by HS diet. Still, mechanisms of the suggesting role warrants further studies.

high-salt diet ; oxidative stress ; inflammation

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