OBJECTIVE: The peritoneal solute transport rate (PSTR) often increases, especially for small solutes, during long-term peritoneal dialysis (PD) treatment. Although the mechanism by which PSTR increases in PD patients is not known, it is likely that an increased PSTR reflects an increased surface area of the peritoneal capillary and post-capillary venules (microvessels), but this has not previously been investigated. The aim of this study was to clarify the relationship between PSTR and peritoneal microvessel alterations in biopsy specimens of peritoneum obtained from PD patients after various times on PD, and the possible contribution of the duration of PD in relation to these alterations. DESIGN: Tissue from the parietal peritoneum was obtained from 22 PD patients (age 48.5 +/- 9.0 years, duration of PD 66.3 +/- 46.6 months, incidence of peritonitis 0.3/patient-year).The patients were subdivided into three groups according to duration of PD: zero months (group 0, n = 4), less than 60 months (group I, n = 7), and more than 60 months (group II; n = 11). METHODS: For each specimen, the relative microvessel area (RVA) calculated as total area of microvessels/total area of peritoneal field, and the relative microvessel number (RVN), calculated as number of microvessels/total area of peritoneal field, were determined. The ratio RVA/RVN was used to assess the average area of microvessels. The PSTR was evaluated for creatinine, glucose, beta2-microglobulin, and albumin using the peritoneal equilibration test. RESULTS: The dialysate-to-plasma concentration ratio (D/P) for creatinine showed a significant positive correlation with both RVA (rho = 0.77, p < 0.001) and RVA/RVN (rho = 0.51, p = 0.01), but not with RVN. The D/P for beta2-microglobulin correlated with RVA (rho = 0.51, p = 0.015) but not with RVN or RVA/RVN. No differences were found between the three groups in the values for RVN, whereas there was an apparent significant increase in RVA with time on PD (p < 0.001 for group 0 vs both groups I and II). Furthermore, in high transporters, RVA tended to be higher in group II than in group I. CONCLUSIONS: The present study demonstrates for the first time that an increased peritoneal solute transport rate (for both creatinine and beta2-microglobulin) is associated with an increased surface area of peritoneal microvessels, especially in patients on long-term PD treatment. This indicates that increased vascularization and/or dilatation of peritoneal microvessels may play a key role in the development of a high PSTR.

This article has been cited by other articles:

				R. T. Krediet, M. M. Zweers, R. van Westrhenen, A. Zegwaard, and D. G. Struijk Effects of reducing the lactate and glucose content of PD solutions on the peritoneum. Is the future GLAD? NDT Plus, October 1, 2008; 1(suppl_4): iv56 - iv62. [Abstract] [Full Text] [PDF]

				A. M. Sherif, M. Nakayama, Y. Maruyama, H. Yoshida, H. Yamamoto, K. Yokoyama, and M. Kawakami Quantitative assessment of the peritoneal vessel density and vasculopathy in CAPD patients Nephrol. Dial. Transplant., June 1, 2006; 21(6): 1675 - 1681. [Abstract] [Full Text] [PDF]

				M. F. Flessner The transport barrier in intraperitoneal therapy Am J Physiol Renal Physiol, March 1, 2005; 288(3): F433 - F442. [Abstract] [Full Text] [PDF]

				S. Ogata, T. Naito, N. Yorioka, K. Kiribayashi, M. Kuratsune, and N. Kohno Effect of lactate and bicarbonate on human peritoneal mesothelial cells, fibroblasts and vascular endothelial cells, and the role of basic fibroblast growth factor Nephrol. Dial. Transplant., November 1, 2004; 19(11): 2831 - 2837. [Abstract] [Full Text] [PDF]

				J. A. Sjoland, R. Smith Pedersen, J. Jespersen, and J. Gram Intraperitoneal heparin reduces peritoneal permeability and increases ultrafiltration in peritoneal dialysis patients Nephrol. Dial. Transplant., May 1, 2004; 19(5): 1264 - 1268. [Abstract] [Full Text] [PDF]

Copyright © 2003 by Multimed Inc.