Primary cultures of human endothelial cells are susceptible to low doses of shiga toxins and undergo apoptosis

Various endothelial cells, with the exception of these from human microvasc ulatures, have been known to resist Shiga toxins (Stxs) in vitro. However, freshly prepared primary cultures of human endothelial cells from the umbil ical vein and artery and the saphenous vein were shown to be killed by a ve ry low dose of Stxs. This cytotoxicity of Stxs involves apoptosis, which se ems to be caused by a mechanism distinct from the well-known action of Stxs to inhibit protein synthesis, since the blockade of protein synthesis by c ycloheximide could not induce apoptosis or enhance the effect of Stxs, Pass aged human endothelial cells have been found to be highly resistant to Stxs , which is consistent with previous reports, and not to show any evidence o f apoptosis even when they are killed by a high dose of Stxs.