Increased leukocyte rolling in newly formed mesenteric vessels in the rat during peritoneal dialysis.
OBJECTIVE
Long-term peritoneal dialysis (PD) is associated with the development of functional and structural alterations of the peritoneal membrane. The present study reports the effects of chronic exposure to PD fluid on mesenteric leukocyte-endothelium interactions, using intravital video microscopy.


METHODS
Rats (n = 7) received 10 mL lactate-buffered 3.86% glucose-containing PD fluid daily during a 5-week period via a subcutaneously implanted mini access port that was connected via a catheter to the peritoneal cavity. In a first control group (n = 8), catheters were implanted but no fluid was instilled; a second control group (n = 8) remained untreated. The number of rolling and adherent leukocytes as well as blood flow and other fluid dynamic variables were analyzed in mesenteric postcapillary (diameter 10-25 mu) and collecting (diameter 26-40 mu) venules. Neovascularization was semiquantitatively assessed after inspection of video images and by light and electron microscopy. Using FITC-labeled albumin, microvascular leakage was examined.


RESULTS
Rats exposed to PD fluid showed a more than twofold increase in the number of rolling leukocytes (p < 0.01); the number of adherent leukocytes was not changed. Furthermore, exposure to PD fluid induced severe neovascularization in rat mesentery. No microvascular leakage was observed in the various groups. The observed differences could not be explained by differences in systemic or local hemodynamic parameters or peripheral leukocyte counts, but is most likely associated with new vessel formation.


CONCLUSIONS
Exposure of rat peritoneal membrane to conventional PD fluid for 5 weeks affected local leukocyte-endothelium interactions. In addition, severe angiogenesis was induced, whereas microvascular permeability remained unaltered.
Zareie
Mohammad
M
Department of Molecular Cell Biology, VU University Medical Center, Amsterdam, The Netherlands.
van Lambalgen
Anton A
AA
De Vriese
An S
AS
van Gelderop
Edwin
E
Lameire
Norbert
N
ter Wee
Piet M
PM
Beelen
Robert H J
RH
van den Born
Jacob
J
Tangelder
Geert-Jan
GJ
D000818:Animals; D002199:Capillary Permeability / Q000187:drug effects / Q000502:physiology; D015314:Dialysis Solutions / Q000493:pharmacokinetics / Q000494:pharmacology*; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000503:physiopathology / Q000648:ultrastructure; D036904:Leukocyte Rolling / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000503:physiopathology / Q000648:ultrastructure; D018919:Neovascularization, Physiologic / Q000187:drug effects* / Q000502:physiology; D010530:Peritoneal Dialysis; D010537:Peritoneum / Q000187:drug effects / Q000503:physiopathology / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D015314:Dialysis Solutions