Hemodialysis-induced upregulation of granulocyte adhesion molecules CD11b/CD18 is independent from 5-lipoxygenase activity.
ABSTRACT Hemodialysis with new cuprophane membranes upregulates expression of granulocyte adhesion molecules and activates 5-lipoxygenase as reflected by the enhanced generation of leukotriene B4 (LTB4). We assessed the role of 5-lipoxygenase activity in hemodialysis-induced upregulation of the granulocyte adhesion molecules, CD11b and CD18, and granulocyte adhesion to human umbilical vein endothelial cells in an ex vivo dialysis model. 5-Lipoxygenase was effectively inhibited by preincubation of human whole blood with the specific inhibitor, BAY X1005. Dialysis with new cuprophane but not with new acrylonitrile membranes significantly upregulated expression of CD11b and CD18 by 6-fold and 4-fold, respectively. Inhibition of 5-lipoxygenase did not affect the expression of CD11b and CD18 during dialysis with either of the two membranes. In contrast to the enhanced expression of CD11b and CD18, adhesion of granulocytes to human umbilical vein endothelial cells did not increase during dialysis, nor was it affected by BAY X1005. These data indicate that ex vivo dialysis with cuprophane membranes upregulates expression of CD11b and CD18 on granulocytes independent of the activation of 5-lipoxygenase.