because cultured human endothelial cells are relatively resistant to the direct cytotoxic actions of endotoxin , it is possible that many of the systemic effects of endotoxin may be caused by stimulation of endothelial cells to produce biologically active mediators which could then act on targets such as smooth muscle cells , fibroblasts , and leukocytes .
C0014257
endothelial
C0225336
endothelial cells