Early atherogenesis in White Carneau pigeons. I. Leukocyte margination and endothelial alterations at the celiac bifurcation.

The addition of 0.2% or more cholesterol to the diet of young White Carneau pigeons produced atherosclerotic lesions within 10 weeks in a 2-sq mm area of the lower thoracic aorta. Concurrent with lesion development, a shift in the shape of endothelial cells from fusiform to polygonal was noted. This shift changed the ratio of endothelial cell width to length from 0.34 in pigeons receiving a control diet to 0.50 in pigeons receiving cholesterol. In contrast, endothelial cells in an atherosclerosis-resistant region 6 cm superior to the test region retained their fusiform shape despite the addition of cholesterol to the pigeon's diet. Cholesterol diets also increased adherence of leukocytes to the luminal surface of the aorta. This was most prevalent at the edge of large lesions (2430 +/- 180 cells/sq mm) and over small lesions (2240 +/- 150 cells/sq mm). Leukocyte adherence was also increased in the central region of large lesions (960 +/- 140 cells/sq mm). In addition, leukocyte activation, as evidence by crawling or spreading cells, was increased almost twofold over small lesions and the edge of large lesions when compared with adherent cells over nonlesion areas.