IMPAIRED LEUKOCYTE ROLLING, ADHESION AND TRANSENDOTHELIAL MIGRATION FOLLOWING CUPROPHANE HEMODIALYSIS

In this study, we investigated how different steps in the extravasatio n process of leucocytes, i.e. rolling, adhesion and transendothelial m igration, are affected by haemodialysis with cuprophane membranes. Hum an leucocytes obtained from whole blood prior to clinical haemodialysi s and from the afferent blood line (post-dialyser) 15 min after the in itiation of dialysis were injected into the mesenteric microcirculatio n of urethane anaesthetized rabbits and analysed for their ability to roll in the microvessels by use of intravital fluorescence microscopy. Moreover, neutrophils from the two leucocyte populations were compare d with respect to chemoattractant-induced adhesion and transmigration across confluent monolayers of bovine aortic endothelial cells. Our re sults show that, as compared with pre-dialysis leucocytes, 15 min of c uprophane haemodialysis impaired leucocyte rolling by 78 +/- 7%, reduc ed N-formyl-methionyl-leucyl-phenylalanin (fMLP)-induced adhesion by 3 4 +/- 9%, and abolished transendothelial migration. These findings dem onstrate that intradialytical activation of leucocytes during cupropha ne haemodialysis severely affects leucocyte functions that are critica l in the extravasation process of these cells at inflammatory tissue s ites, and thus may help explain the increased susceptibility to infect ions observed in patients on chronic haemodialysis.