Numata Miwako, Nakayama Masaaki, Nimura Satoshi, Kawakami Makio, Lindholm Bengt, Kawaguchi Yoshindo
Division of Kidney and Hypertension, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan.
Perit Dial Int. 2003 Mar-Apr;23(2):116-22.
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.
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).
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.
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.
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.
在长期腹膜透析（PD）治疗期间，腹膜溶质转运率（PSTR）常常升高，尤其是对于小分子溶质。虽然PD患者中PSTR升高的机制尚不清楚，但PSTR升高可能反映了腹膜毛细血管和毛细血管后微静脉（微血管）表面积增加，不过此前尚未对此进行研究。本研究的目的是阐明PD不同时间后从PD患者获取的腹膜活检标本中PSTR与腹膜微血管改变之间的关系，以及PD持续时间与这些改变的可能关联。
从22例PD患者（年龄48.5±9.0岁，PD持续时间66.3±46.6个月，腹膜炎发生率0.3/患者年）获取壁层腹膜组织。根据PD持续时间将患者分为三组：0个月（0组，n = 4）、少于60个月（I组，n = 7）和多于60个月（II组，n = 11）。
对于每个标本，测定以微血管总面积/腹膜视野总面积计算的相对微血管面积（RVA），以及以微血管数量/腹膜视野总面积计算的相对微血管数量（RVN）。RVA/RVN比值用于评估微血管的平均面积。使用腹膜平衡试验评估肌酐、葡萄糖、β2-微球蛋白和白蛋白的PSTR。
肌酐的透析液与血浆浓度比值（D/P）与RVA（ρ = 0.77，p < 0.001）和RVA/RVN（ρ = 0.51，p = 0.01）均呈显著正相关，但与RVN无关。β2-微球蛋白的D/P与RVA（ρ = 0.51，p = 0.015）相关，但与RVN或RVA/RVN无关。三组之间RVN值无差异，而随着PD时间延长，RVA明显显著增加（0组与I组和II组相比，p < 0.001）。此外，在高转运者中，II组的RVA往往高于I组。
本研究首次表明，腹膜溶质转运率升高（对于肌酐和β2-微球蛋白而言）与腹膜微血管表面积增加有关，尤其是在长期接受PD治疗的患者中。这表明腹膜微血管血管化增加和/或扩张可能在高PSTR的发生中起关键作用。
