Perlecan is a large multidomain proteoglycan that binds to and cross-links many extracellular matrix (ECM) components and cell-surface molecules.Perlecan is synthesized by both vascular endothelial and smooth muscle cells and deposited in the extracellular matrix. Perlecan is highly conserved across species and the available data indicate that it has evolved from ancient ancestors by gene duplication and exon shuffling.Perlecan is a key component of the vascular extracellular matrix, here it interacts with a variety of other matrix components and helps to maintain the endothelial barrier function. Perlecan is a potent inhibitor of smooth muscle cell proliferation and is thus thought to help maintain vascular homeostasis. Perlecan can also promote growth factor activity and thus stimulate endothelial growth and re-generation.