Effects of Aortic Stenosis on Renal Renin, Angiotensin Receptor, Endothelin and NOS Gene Expression in Rats

Abstract

Background/Aims: Published data regarding the effects of common cardiovascular diseases, i.e. aortic stenosis on renal regulation of major vasoconstrictive (renin, endothelins) and vasodilatory systems (NO) are controversial. Therefore we aimed to evaluate the effects of chronic aortic stenosis on the renal renin-angiotensin, endothelin and NO systems. Methods: Experimental supravalvular aortic stenosis was induced by using silver clips with a 0.6 mm internal diameter on the ascending aorta of weanling rats. Renal endothelin-1 (ET-1), endothelin-3 (ET-3), renin, AT_1a, AT_1b, eNOS, and bNOS gene expression were assessed by RNase protection assay. Results: Renal renin gene expression increased twofold in rats with aortic stenosis. In contrast, renal ET-1, ET-3, eNOS, bNOS, and AT_1a, AT_1b gene expression were unchanged in rats with aortic stenosis. Conclusion: Our study demonstrates that in rats with severe experimental supravalvular aortic stenosis only renal renin gene expression is stimulated. This contrasts with severe heart failure where endothelins and NO synthases are also upregulated. Different patterns of regulation of renal vasoactive mediators may be of importance for the extent of the renal impairment associated with aortic stenosis, and may be correlated with the severity of congestive heart failure.