Book of Abstracts - New Frontiers 2022

Abstracts of poster presentations

THE EFFECT OF PERIVASCULAR ADIPOSE TISSUE IN INTERACTION WITH ENDOGENOUS AND EXOGENOUS HYDROGEN SULFIDE IN VASOACTIVE RESPONSES OF ISOLATED THORACIC AORTA IN NORMOTENSIVE AND SPONTANEOUSLY HYPERTENSIVE RATS

S. Golas, S. Cacanyiova, A. Berenyiova

Institute of Normal and Pathological Physiology, Center of Experimental Medicine, Bratislava, Slovakia

Perivascular adipose tissue (PVAT) plays an important role in the regulation of cardiovascular system. One of the crucial substances produced by PVAT is hydrogen sulfide (H 2 S) with biphasic vasomotor effect on cardiovascular system. The aim of this study was to evaluate the mutual relationship between PVAT and exogenous and endogenous H 2 S in the vasoactive responses of thoracic aorta (TA) isolated from adult normotensive (Wistar) rats and spontaneous hypertensive rats (SHRs). The changes in isometric tension were evaluated after application of exogenous acetylcholine (Ach), noradrenaline (NA) and exogenous H 2 S donor (Na 2 S) in TA with preserved or denuded PVAT. To inhibit the endogenous H 2 S production, the inhibitor of cystathionine γ lyase, propargylglycine, was used. Regardless of the strain, PVAT revealed anti-contractile effect on the vasoconstrictor responses induced by exogenous NA. In both, Wistar and SHRs, PVAT worsened the endothelial-dependent vasorelaxant response induced by Ach. In Wistar rats, H 2 S produced by the vascular wall as well as PVAT did not participate on the vasoactive response induced by exogenous NA and Ach. However, in SHR, H 2 S produced by both, the vascular wall and PVAT had a pro-contractile effect on the vasoconstrictor response induced by exogenous NA. On the other hand, even if H 2 S produced by PVAT did not contribute to endothelium-dependent vasorelaxant responses, H 2 S produced by the vascular wall had a pro-relaxant effect in SHR. In the SHRs, regardless of the presence of PVAT, we confirmed an increased maximal vasorelaxant phase of the Na 2 S-induced response compared with that in the Wistar rats. In Wistar rats, PVAT did not affect the biphasic vasoactive response induced by H 2 S; however, in SHRs, the rings with PVAT revealed significantly increased vasorelaxation induced by exogenous H 2 S. We confirmed that although PVAT of TA in SHRs aggravated endothelial function, it revealed an anticontractile effect mediated by the release of unknown factors and an increased vasorelaxant response to H 2 S donors. Endogenously produced H 2 S manifested a dual effect depending on the type of signaling pathway triggered. H 2 S produced by PVAT, and the vascular wall had pro contractile effects and could contribute to pathological changes in essential hypertension. However, H 2 S produced by the vascular wall had a pro-relaxation effect and could represent a form of vasoactive compensatory mechanism to balance impaired vascular tone regulation.

Keywords: Perivascular adipose tissue, H 2 S, SHR

Funding: This study was supported by grant APVV-20-0421

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