In vivo visualization of hemodialysis-induced alterations in leukocyte–endothelial interactions

Abstract

In vivo visualization of hemodialysis-induced alterations in leukocyte–endothelial interactions.BackgroundThe aim of this study was to develop a model for hemodialysis (HD) in small animals using conventional dialysis equipment that would allow the intravital microscopic observation of leukocyte–endothelial interactions in vivo.MethodsCuprophan dialyzers were adapted to obtain a similar ratio of membrane area to blood volume as in clinical HD. A silicone ring was inserted into the dialyzer's inlet to limit the number of blood-perfused capillaries. Rabbits were dialyzed for one hour without a dialysate flow.ResultsExtracorporeal circulation with the cuprophan dialyzer resulted in a transient leukopenia and complement activation. At the nadir of leukopenia, leukocytes that rolled along the venular wall were scarcely observed, whereas rolling was abundant (54 ± 9 per min) prior to extracorporeal circulation. The adhesion of leukocytes to the vascular endothelium was not induced. After 60 minutes, rolling of leukocytes was still reduced by 73 ± 5.5%, despite the full recovery of circulating leukocyte counts. Extracorporeal circulation without a dialyzer also tended to reduce leukocyte rolling, although systemic leukocyte counts were not affected.ConclusionsThe use of adapted conventional cuprophan hemodialyzers in rabbits yielded a transient leukopenia similar to that in clinical HD. Using intravital microscopy, we demonstrated impairment of leukocyte–endothelial interactions. In addition, our data indicate that tissues, in which leukocytes can roll and adhere, are not automatically sites of leukocyte sequestration during HD-induced leukopenia