The effects of cholesterol (CHO) and
cholesterol autooxidation derivatives (CAD) on the
endocytosis of cationized ferritin (CF) by endothelial
cells have been investigated. The effect of both
substances on the activity of lysosomal enzymes
dipeptidyl peptidase 1 (DPP 1) and dipeptidyl
peptidase 11 (DPP 11) was also studied. Treatment of
rats with CAD induced striking alterations in the
ultrastructure of endothelial cells and makes it
impossible to analyze the effect of this toxin on
endocytosis processes. In contrast, CHO-treated cells
displayed a good ultrastructural preservation and
showed an increased ability to endocyte ferritin, as
compared with controls. Both DPPI and DPP 11
activities increased after 3 weeks of CAD or CHO
treatment. Our results indicate that although CHO
damage endothelial cells, the most important effects
could be attributed to CAD which usually
accompanies CHO-supplemented diets