PLASMA-PROTEIN ENTRY AND RETENTION IN THE VASCULAR WALL - POSSIBLE FACTORS IN ATHEROGENESIS

Various experiments are described that relate to measuring the uptake of plasma proteins by the walls of various large blood vessels of the rabbit. The rate of uptake across the intimal surface is not uniform, there being punctate regions of elevated transport. In addition, the r ate of transport appears to be considerably higher across veins, pulmo nary vessels, and the ascending aorta than across more peripheral arte ries. Although larger proteins such as fibrinogen and low-density lipo protein are transported more slowly than smaller ones, they appear to be retained to a greater extent in the inner layers of arteries than i n pulmonary vessels and veins. Retention is greatly enhanced when coll ars are placed around the arteries and may be involved in the intimal hyperplasia that is seen in such vessels. Thus it appears that it may be the relative extent of entrapment of large atherogenic proteins tha t determines the appearance of lesions at different sites in the cardi ovascular system, in addition to the rates at which they exchange acro ss the blood-wall interface.