Instillations of low pH lactate buffer, a high glucose concentration and glucose degradation products contribute differently and often cumulatively to peritoneal injury in vivo.

Background. Chronic exposure to conventional peritoneal dialysis fluid (PDF) is associated with functional and structural alterations of the peritoneal membrane.

We show that PD fluid-induced cellular and morphological alterations of the peritoneal membrane are generally reversible.

Both uraemia and PD fluid exposure result in pathological alterations of the peritoneum. However, uraemia did not induce major additive effects to PD fluid-induced injury. These results substantially contribute to the understanding of the pathobiology of the peritoneum under PD conditions.

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 μ) and collecting (diameter 26 – 40 μ) 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.