OXIDIZED LOW-DENSITY-LIPOPROTEIN TRIGGERS PROGRAMMED DEATH OF ENDOTHELIAL-CELLS

Incubation of bovine aortic as well as human umbilical vein endothelia l cells with either oxidized or native low-density-lipoprotein in the presence of trace amounts of copper induced morphological changes of t he cells and chromatin fragmentation characteristic for programmed cel l death. Shrinkage of cells was evident after 6 to 8 hours of incubati on and clearly preceded release of lactate dehydrogenase as a marker o f cell permeability. Condensation of nuclear chromatin and internucleo somal cleavage was demonstrated by Hoechst staining and gel electropho resis, respectively. Thus, by inducing active death of endothelial cel ls oxidized low-density-lipoprotein might negatively influence tissue homeostasis of the endothelium and thereby promote the development of atherosclerotic plaques.