Transport in rat vessel walls. II. Macromolecular leakage and focal spot size growth in rat arteries and veins

Transendothelial lipid transport into and spread in the subendothelial intima of large arteries, and subsequent lipid accumulation, appear to start plaque formation. We experimentally examine transendothelial horseradish peroxidase (HRP) transport in vessels that are usually, e.g., pulmonary artery (PA), or almost always, e.g., inferior vena cava (IVC), atherosclerosis resistant vs. disease prone, e.g., aorta, vessels. In these vessels, HRP traverses the endothelium at isolated, focal spots, rather than uniformly, for short circulation times. For femoral vein HRP introduction, PA spots have 30-s radii [∼53.2 μm (SD10.4); compare aorta: 54.6 μm (SD8.75)] and grow quickly from 30 s to 1 min (40%, P 0.05). This trend resembles the aorta, suggesting the PA has a similarly sparse intima. With carotid artery (CA) HRP introduction, the 30-s spot (132.86 ± 37.32 μm) is far larger than the PAs, grows little (∼28%, P < 0.05) from 30 to 60 s, and is much flatter than the artery...