ABSTRACT

The vascular endothelium is comprised of a single endothelial cell monolayer with a thickness of 15 µm. The vascular endothelium can maintain the integrity of blood/tissue barrier, allowing important cellular processes such as nutrients permeability and impermeability to toxins. The endothelium also relays adaptive messages from the arterial wall to sustained pressures (vasoreactivity and haemostasis). The endothelium is considered a tight barrier; nevertheless, it handles a continuous fl ow of small molecules by transcytosis, a process by which various macromolecules, for example glucose, small peptides, high-density lipoprotein (HDL) are transported across the interior of the cells (Tuma and Hubbard 2003). An important feature of the endothelium is the presence of cholesterol-rich lipid microdomains, caveolae and rafts in the membrane which are relay points to throw up or to transmit messages from or to the vascular wall (Touyz 2006).