The mass transport of the arterial wall: effect of mechanical stresses and vasoactive agents, including nitrates.

Arteriosclerosis is a slowly progressing disease. It is important, therefore, to seek means of delaying its progress both in pre-symptomatic patients and in patients with circulatory disorders. Various features of the disease, among them the focal distribution of the lesions, imply that changes in blood composition cannot alone account for its occurrence and that a contribution must come from the arterial wall, possibly from its mass transport properties. We review recent findings concerning arterial wall mass transport. Movement of material occurs right across the arterial wall from the lumen to the adventitial lymph and it appears that the media may act as a barrier to the efflux of material from the wall. Work currently in progress suggests that among factors which influence arterial wall mass transport are the level of arterial blood pressure, endothelial permeability and the tone of the medial smooth muscle. Further fundamental study is needed but consideration would now seem justified as to whether the progression of arteriosclerosis might be influenced by pharmacological agents which affect the wall mass transport.