Naslov
High salt diet affects the cerebral vascular reactivity – comparative studies in animals and humans

Autori
Drenjančević, Ines

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
FAME2023 Program, oral, poster abstracts / - , 2023, 70-70

Skup
FAME2023

Mjesto i datum
Mátraháza, Mađarska, 07.06.2023. - 09.06.2023

Vrsta sudjelovanja
Plenarno

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
High salt diet, microcirculation, oxidative stress, vasodilation

Sažetak
A numerous data confirmed that high salt (HS) diet had a deleterious effect on endothelium-dependent vascular reactivity, both in microcirculation and macrocirculation. HS diet physiologically suppresses renin-angiotensin system (RAS). Our results in middle cerebral arteries (MCA) of Sprague-Dawley rats on a HS diet have shown significantly impaired vasodilator responses to acetylcholine (AChID) and flow-induced dilation. The underlying mechanisms were increased vascular and systemic oxidative stress and decreased vascular production of NO, together with altered balance between vasoactive prostaglandins and eicosanoids, such as metabolites of COX1, 2 and epoxygenases. This was related to decreased expression of antioxidative defense systems. Scavenging of reactive oxygen species with TEMPOL restored NO production and vascular reactivity. Importantly, chronic low-dose ANG II supplementation in high salt fed rats restored FID of MCAs. ANG II changed the protein/gene expression of COXs, HIF-1α and VEGF and significantly increased GPx4 and EC-SOD antioxidative enzyme expression, decreased systemic oxidative stress, decreased superoxide/ROS levels and increased NO bioavailability in the vascular wall. Interestingly, similar was observed in our human studies: HS diet led to impaired peripheral microvascular and macrovascular reactivity in response to ACh and post-occlusive hyperemia. Plasma renin activity (PRA) and serum aldosterone level were significantly suppressed after HS diet and markers of oxidative stress were increased. Impaired AChID and increased salt intake, as well as impaired AChID and suppressed RAS were significantly positively correlated. Impaired vasorelaxation and increase in oxidative stress could have been prevented by concomitant intake of antioxidants together with HS diet. Furthermore, in healthy young humans on HS diet, cerebral blood flow in response to orthostatic test was preserved due to altered vascular reactivity of MCA, with increased cerebrovascular resistance and blunted baroreceptor sensitivity and sympathetic activity. Taken altogether, our results support conclusion that physiological levels of circulating ANG II are crucial to maintain the HIF-1α dependent mechanisms of endothelium-dependent vasodilation and vascular oxidative balance without affecting mean arterial pressure. Suppression of sympathetic activity during HS diet represents a physiological response. Funding: IP-MEFOS-2023 grant (PI_ Ines Drenjančević)

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

Napomena
Funding: IP-MEFOS-2023 grant (PI_ Ines Drenjančević)

Keynote lecture

POVEZANOST RADA