Expression of endothelial leukocyte adhesion molecule-1 in septic but not traumatic/hypovolemic shock in the baboon

Baboons were subjected to septic or traumatic/hypovolemic shock and their tissues were examined for the de novo expression of endothelial leukocyte adhesion molecule 1 (ELAM-1), using immunohistochemical techniques. In animals with septic shock induced with live Escherichia coli, there was widespread expression of ELAM-1, recognized by monoclonal antibodies H4/18 or ENA-1 in most tissues examined with strong staining in the lung, liver, and kidneys. Endothelial leukocyte adhesion molecule 1 expression was evident in capillaries, venules, small veins, arterioles, and arteries. In contrast, baboons with traumatic/hypovolemic shock had minimal levels of focal ELAM expression in all organs studied. Similarly evidence of neutrophil activation, measured by granulocyte elastase levels in the plasma was much more pronounced in animals with septic shock. The study documents that lipopolysaccharide (LPS)- and cytokine-induced endothelial activation occurs in vivo in septic shock. Much higher levels of ELAM-1 expression and plasma granulocyte-elastase titer in septic shock, as contrasted with traumatic/hypovolemic shock, are consistent with the higher levels of circulating tumor necrosis factor, other cytokines, and LPS in sepsis.