Aorta Remodelling Associated with Calcitonin Gene Related Peptide Concentration in Rats with Arterial Hypertension

Abstract

Long-term hypertension in arteries leads to remodelling of the arterial wall. We focused on morphological changes in the wall of the subrenal aorta in rats suffering from arterial hypertension and chronic renal failure induced by 5/6 nephrectomy (NX). We quantified the area of the profile of the arterial lumen, the volume fraction of elastin and smooth muscle cells (SMC) in the tunica media, the thickness of the intima-media, the length density of elastin lamellae, the lamellar unit thickness and the lamellar number. Calcitonin gene related peptide (CGRP) was assayed in extracts of aortic tissue and in plasma. Ten days after the subtotal nephrectomy, the structure of the aorta of NX rats did not differ compared to control animals. Pronounced structural changes were observed ten weeks after 5/6 nephrectomy. The area of the lumen profile, the elastin volume fraction and the elastin lamellar number in the tunica media were all significantly higher (p < 0.001) in NX than in control animals. The SMC volume fraction in the tunica media and the lamellar unit thickness were lower (p < 0.001) in NX than in control animals. The CGRP concentration was significantly higher (p < 0.05) in the aortas and in plasma of NX rats both ten days and ten weeks after operation when compared to sham operated animals. Our study demonstrated intensive remodelling of the aorta over the course of 10 weeks following induction of chronic renal failure. This was associated with a long-term increase in calcitonin gene related pep tide concentrations in the plasma and aorta.