Vascular laminins in physiology and pathology

Review on vascular laminins. In the healthy vessel, basement membranes (BMs) are the main ECM structures found in the vessel wall, underlying endothelium and surrounding vascular smooth muscle cells. Laminin α4 and α5 chains are the major α chains occurring in endothelial BMs and in vascular smooth muscle BMs. In most cases, laminins α4 and α5 combine with laminin β1 and γ1 chains to form laminins-411 and -511 in endothelial BMs; however, there is also evidence for the expression of laminin β2 in several tissues suggesting the additional existence of laminins-421 and -521 in endothelial BMs. While laminin α2 does not occur in endothelial BMs it can occur in association with perivascular cells including smooth muscle BMs of large arteries, such as the aorta, but not of smaller arterioles. There is no laminin α1 in endothelial or smooth muscle BMs regardless of tissue or species.