Extracellular matrix and smooth muscle cells

The arterial wall is a highly organised structure of cells and extracellular matrix (ECM) (see review by Adizugel et al. [1]). The ECM is synthesized by the VSMCs within the arterial wall, which then interact with the ECM through cell-matrix contacts. Many different forms of ECM are present in the arterial wall including both collagenous and non-collagenous proteins. In the intima, endothelial cells sit upon a layer of basement membrane composed of laminin, nidogen, perlecan, fibronectin and type IV collagen. In the media, VSMCs are surrounded by basement membrane, which is in turn embedded in fibrillar collagens type I, III and V, collagen type XVIII, fibronectin, and glycoproteins including proteoglycans and cartilage oligomeric matrix protein (COMP, thrombospondin 5) [2, 3].