Book of Abstracts - New Frontiers 2022

Abstracts of poster presentations

HIGH CONCENTRATION OF URIC ACID DID NOT AFFECT ENDOTHELIAL FUNCTION OF VARIOUS - SMALL, MEDIUM-SIZED AND LARGE ARTERIES FROM AGED WKY RATS P. Balis 1 , A. Berenyiova 1 , J. Radosinska 2,3 , M. Kvandova 4 , I. Bernatova 1 , M. Kluknavsky 1 , A. Puzserova 1 1 Centre of Experimental Medicine, Slovak Academy of Sciences, Institute of Normal and Pathological Physiology, Bratislava, Slovakia; 2 Institute of Physiology, Faculty of Medicine, Comenius University, Bratislava, Slovakia; 3 Centre of Experimental Medicine, Slovak Academy of Sciences, Institute for Heart Research, Bratislava, Slovakia; 4 Center for Cardiology, Department of Cardiology 1-Molecular Cardiology, University Medical Center, Johannes Gutenberg University, Mainz, Germany Aim: The long-term increase in uric acid (UA) concentration represents a new cardiovascular risk factor constantly attracting scientific attention. It is however still not clear whether UA is a causative risk factor in endothelial dysfunction, an inert marker, or an endothelium-protective molecule concerning its antioxidant properties. Nevertheless, the minority of studies have been conducted to investigate its effect on vascular endothelium-dependent relaxation. Therefore, in our in vitro study, we focused on the effect of high concentrations of UA on arterial endothelial function of old normotensive rats. Methods and results: For the study, male Wistar-Kyoto (WKY) rats were used. The acute effect of UA was analyzed by vascular reactivity measurements, using in vitro isometric tension studies by wire myograph - small mesenteric arteries (SMAs) and femoral arteries (FAs), and using organ chamber - aorta. Endothelium-dependent vasorelaxation using acetylcholine (ACh) test was determined before and after 1 hour incubation of isolated arteries with UA: 600 µmol/l (arteries from 68 -week- old rats) and 1200 µmol/l (57-week-old). 20-week-old WKY were used as the corresponding control to aged animals. Impaired endothelial function was determined in FAs and aortas from old (57- and 68-weeks) WKY as compared with arteries from young 20-weeksold rats. On the other hand, we did not observe any acute effects of high concentrations of UA on endothelial function. ACh-induced vasorelaxation and pD2 values in the condition of high concentration of UA were not changed as compared to vasorelaxations before incubations. Conclusion: Acute exposure of the resistant SMAs, FAs, and aortas isolated from aged WKY rats to a high concentration of UA did not provoke changes in endothelial function. Thus, the role of UA in the worsening of the endothelial dysfunction of aged rats is not supported by our data. Therefore, further studies are needed to determine whether hyperuricemia per se is causally associated with endothelial dysfunction.

Keywords: uric acide, vasorelaxation, hyperuricemia, old normotensive rats

Funding:Supported by the grants VEGA 2/0190/17, 2/0158/20, 2/0153/21, and APVV-16-0263.

70