Association between pre-dialysis peritoneal microvascular density and baseline peritoneal solute transport status

Objective To evaluate the relationship between pre-dialysis peritoneal microvascular density and baseline peritoneal solute transport status by immunohistochemical staining, and to investigate the morphological bases for the evaluation of baseline solute transport status. Methods Non-diabetic patients newly treated with continuous ambulatory peritoneal dialysis (CAPD) in the Peritoneal Dialysis Unit of Renal Department, Beijing Friendship Hospital were enrolled in this study. Parietal peritoneal biopsies were obtained during implanting peritoneal dialytic catheters. Peritoneal microvascular density (MVD) was evaluated by anti-CD34 antibody staining. After commencing CAPD for 4-6 weeks, a standard peritoneal equilibration test (PET) was performed, and the dialysate-to-plasma concentration ratio for creatinine at 4 hours (D/Pcr) was determined. The 24-hour peritoneal protein excretion (PPE) was assayed. Result Thirty-two CAPD patients without the history of peritonitis were included, and were divided into two groups based on D/Pcr: group H with the D/Pcr 0.65 (n=19), and group L with the D/Pcr ≤ 0.65 (n=13). After corrections for body surface area, residual renal function, mean arterial pressure, administration of antihypertensive agents, prescription of 2.5% glucose-base peritoneal dialysate, hemoglobin, CRP and serum albumin, MVD was significantly higher in group H than in group L (P=0.001). MVD showed significant correlation with D/Pcr (p=0.035), but not with PPE (P=0.683). Conclusion In non-diabetic CAPD patients, pre-dialysis peritoneal microvascular density is positively correlated with baseline peritoneal small solute transport rate, but not with 24-hour peritoneal protein excretion. The later is possibly restricted by peritoneal inherent permeability.