Extracellular matrix proteins in aortic stenosis

Maiko Matsui, Rihab Bouchareb

Extracellular Matrix Proteins (ECM) are the major protein component of the aortic valve. ECM proteins ensure the normal function of the valve by sensing and transducing mechanical stress signals to the Interstitial Valve Cells (VICs). The fibrosa, spongiosa, and ventricularis are the three layers making up the aortic valve. Each layer in the AV has a distinguished ECM composition. Indeed, the fibrosa is mainly composed of collagen type I and III. In contrast, the spongiosa is composed of Proteoglycans (PGs) and Glycosaminoglycan (GAG). Finally the ventricularis is composed of elastin. A disturbance in the ECM matrix may subsequently affect valve cell signaling and promote valve calcification. The use of proteomic approaches have helped to identify differences in expression levels of ECM proteins in the different layers of the aortic valve. This review will discuss the role of changes in the composition of ECM proteins in aortic stenosis and explore the latest findings regarding the ECM network in valvular heart disease.