Ex Vivo Analysis of an Association of Mechanical Strength of Dilated Ascending Aorta with Tissue Matrix Metalloproteinases and Cytokines

Abstract

We analyzed the associations of the mechanical strength of dilated ascending aorta wall (intraoperative samples from 30 patients with non-syndromic aneurysms) with tissue MMPs and the cytokine system. Some samples were stretched to break on an Instron 3343 testing machine and the tensile strength was calculated; others were homogenized and the concentrations of MMP-1, MMP-2, MMP-7, their inhibitors (TIMP-1 and TIMP-2), and pro- and anti-inflammatory cytokines were determined by ELISA. Direct correlations between aortic tensile strength and concentrations of IL-10 (r=0.46), TNFα (r=0.60), and vessel diameter (r=0.67) and an inverse correlation with patient's age (r=-0.59) were revealed. Compensatory mechanisms supporting the strength of the ascending aortic aneurysm are possible. No associations of MMP-1, MMP-7, TIMP-1, and TIMP-2 with tensile strength and aortic diameter were found.

Keywords: ascending aortic aneurysm; cytokines; interleukins; mechanical strength; metalloproteinases.