In vivo visualization of hemodialysis-induced alterations in leukocyte-endothelial interactions.
BACKGROUND
The 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.


METHODS
Cuprophan 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.


RESULTS
Extracorporeal 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.


CONCLUSIONS
The 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.
Van Teijlingen
M E
ME
Laboratory for Physiology and Department of Nephrology, Institute for Cardiovascular Research (ICaR-VU), Vrije Universiteit, Amsterdam, The Netherlands. me.van_teijlingen.physiol@med.vu.nl
Borgdorff
P
P
Van Wijhe
M H
MH
Van Lambalgen
T A
TA
Wee
P M
PM
Tangelder
G J
GJ
D000818:Animals; D001672:Biocompatible Materials; D002448:Cell Adhesion; D002482:Cellulose / Q000031:analogs & derivatives; D003167:Complement Activation; D004730:Endothelium, Vascular / Q000502:physiology*; D004867:Equipment Design; D005112:Extracorporeal Circulation; D007958:Leukocyte Count; D007962:Leukocytes / Q000166:cytology / Q000502:physiology*; D007970:Leukopenia / Q000209:etiology; D011817:Rabbits; D006435:Renal Dialysis / Q000009:adverse effects / Q000295:instrumentation; D013152:Splanchnic Circulation
D001672:Biocompatible Materials; D002482:Cellulose; C009865:cuprammonium cellulose