Cell Biology of Vessels

The vascular system comprises large-, medium- and small-sized vessels, classified as arteries or veins. This system is extremely diverse in structure, architecture and physiology. The vascular wall is composed of three layers: intima, media and adventitia. The intima layer is mainly formed by a monolayer of endothelial cells, which are important to the regulation of vascular smooth cell relaxation and contraction by the production of endothelial-derived relaxing and constricting factors. The media layer is mostly composed by vascular smooth muscle cells that play a major role in changes of vascular diameter and maintenance of vascular tone. In the adventitia, the perivascular adipose tissue has been described as an important regulator of vascular function and inflammation. In this chapter, we will describe the phenotype of endothelial cells, vascular smooth muscle cells and perivascular adipose tissue, focusing on their role to maintain vascular tone and integrity in health and disease.