[Arterial ageing of aorta and atherosclerosis--with special reference to elastin]

Ageing of the arterial wall is defined as the age-related structural and functional changes in arteries. These changes include distension of the lumen, kinking of the artery, and rigidity of the arterial wall. Distension of the arterial luminal diameter with hardening of the arterial wall causes chronic ischemia in peripheral tissues, leading to age-related deterioration of the organs. The ensuing pathological modification in blood circulation is mainly linked to the decrease in the elastic recoil of the arteries and to the increasing difficulty of pumping systolic blood volume towards the periphery. This results in increased systolic blood pressure in the elderly and an increasing load on the ageing heart. Age-related changes in elastic arteries are characterized as degenerative changes in the SMCs of the media associated with depositions of collagen fibers and the fragmentation of elastic fibers. Data obtained from in vivo experiments indicate that the susceptibility of aged arteries to atherogenic stimuli might be related to intrinsic cellular changes with age. Substances that can regulate the function of vascular wall cells may be continuously present in the vessel walls, perhaps as components of super-extracellular matrix complexes. One type of substance is the functional domain structure of extracellular matrix molecules exposed to specific receptors or binding proteins on the surface of the cells. The role of extracellular matrices, especially elastin, on cultured vascular cells has been discussed.