Peritoneal Equilibration Test Research Articles

Peritoneal Equilibration Test and Patient Outcomes.

Although a peritoneal equilibration test yields data on three parameters (4-hour dialysate/plasma creatinine, 4- to 0-hour dialysate glucose, and 4-hour ultrafiltration volume), all studies have focused on the prognostic value of dialysate/plasma creatinine for patients undergoing peritoneal dialysis. Because dialysate 4- to 0-hour glucose and ultrafiltration volume may be superior in predicting daily ultrafiltration, the likely mechanism for the association of peritoneal equilibration test results with outcomes, we hypothesized that they are superior to dialysate/plasma creatinine for risk prediction. We examined unadjusted and adjusted associations of three peritoneal equilibration test parameters with all-cause mortality, technique failure, and hospitalization rate in 10,142 patients on peritoneal dialysis treated between January 1, 2007 and December 31, 2011 in 764 dialysis facilities operated by a single large dialysis organization in the United States, with a median follow-up period of 15.8 months; 87% were treated with automated peritoneal dialysis. Demographic and clinical parameters explained only 8% of the variability in dialysate/plasma creatinine. There was a linear association between dialysate/plasma creatinine and mortality (adjusted hazards ratio per 0.1 unit higher, 1.07; 95% confidence interval, 1.02 to 1.13) and hospitalization rate (adjusted incidence rate ratio per 0.1 unit higher, 1.05; 95% confidence interval, 1.03 to 1.06). Dialysate/plasma creatinine and dialysate glucose were highly correlated (r=-0.84) and yielded similar risk prediction. Ultrafiltration volume was inversely related with hospitalization rate but not with all-cause mortality. None of the parameters were associated with technique failure. Adding 4- to 0-hour dialysate glucose, ultrafiltration volume, or both did not result in any improvement in risk prediction with dialysate/plasma creatinine alone. This analysis from a large contemporary cohort treated primarily with automated peritoneal dialysis validates dialysate/plasma creatinine as a robust predictor of outcomes in patients treated with peritoneal dialysis.

Adecuación en diálisis peritoneal pediátrica. Del test de equilibrio peritoneal a las aquaporinas

An evaluation of the characteristics of peritoneal solute and water transport is essential to assess the suitability of prescribing dialysis in patients suffering from chronic renal disease. There are currently a series of models to perform this evaluation. The peritoneal equilibration test (PET) evaluates the peritoneal transport capacity, classifying the patients into four transport categories: high, high-average, low-average, and low. The short PET enables the same evaluation to be made in only 2hours, and has been validated in paediatric patients. On the other hand, the MiniPET provides additional information by evaluating the free water transport capacity by the ultra-small pores, and the Accelerated Peritoneal Examination Time (APEX) evaluates the time when the glucose and urea equilibration curves cross, and has been proposed as the optimum dwell time to achieve adequate ultrafiltration. An analysis is presented on the current information on these diagnostic methods as regards free water transport via aquaporins, which could be an important tool in optimising solute and water transport in patients on chronic peritoneal dialysis, particularly as regards the cardiovascular prognosis.

Association between Redox Status of Serum Albumin and Peritoneal Membrane Transport Properties in Patients on Peritoneal Dialysis

Background: Albumin, the most abundant protein in the extracellular fluid, displays an important antioxidant activity. Increased levels of oxidized albumin levels (high human non-mercaptoalbumin (HNA) level) have been reported in the serum of patients with end-stage renal disease. In this study, we attempted to identify the albumin redox status in the serum of patients on peritoneal dialysis (PD) and examined the relationship between these proteins and the transport type of the peritoneal membrane and other clinical and laboratory variables. Methods: We performed a cross-sectional study of a cohort of 80 patients with end-stage renal disease receiving PD. Peritoneal transport characteristics were identified and after peritoneal equilibration test patients were grouped as high (high(H)/high-average (HA) group, n = 31) or low (low (L)/low-average (LA) group, n = 49) transporters. The redox state of human serum albumin was measured using high-performance liquid chromatography. Results: The fraction of human mercaptoalbumin (HMA) showed significantly higher values in patients with high transport status than those with low transport status (f(HMA) 64.0 ± 5.4 and 52.7 ± 10.4%, respectively). Our data showed that the H/HA transport characteristic was associated with lower albumin (3.76 ± 0.48 vs. 4.00 ± 0.35, p < 0.05), and lower levels of advanced oxidized protein product (p = 0.008) when compared with the L/LA type. A correlation analysis showed that there was a positive correlation between dialysate/plasma (D/P) creatinine and f(HMA) levels (r = 0.511, p < 0.0001), as well as hemoglobin levels r = 0.231, p = 0.044 and a negative correlation between D/P creatinine and serum albumin, cholesterol and LDL levels (r = -0.236, p = 0.039; r = -0.237, p = 0.038; r = -0.272, p = 0.018, respectively). Conclusions: This study showed that higher serum levels of reduced albumin f(HMA) appear to be associated with high/high average peritoneal membrane transport characteristics in the incident PD patients.

Update on Peritoneal Dialysis: Core Curriculum 2016

Update on Peritoneal Dialysis: Core Curriculum 2016

Vascular endothelial growth factor receptor-3 is a novel target to improve net ultrafiltration in methylglyoxal-induced peritoneal injury

Appropriate fluid balance is important for good clinical outcomes and survival in patients on peritoneal dialysis. We recently reported that lymphangiogenesis associated with fibrosis developed in the peritoneal cavity via the transforming growth factor-β1-vascular endothelial growth factor-C (VEGF-C) pathway. We investigated whether VEGF receptor-3 (VEGFR-3), the receptor for VEGF-C and -D, might be a new target to improve net ultrafiltration by using adenovirus-expressing soluble VEGFR-3 (Adeno-sVEGFR-3) in rodent models of peritoneal injury induced by methylglyoxal (MGO). We demonstrated that lymphangiogenesis developed in these MGO models, especially in the diaphragm, indicating that lymphangiogenesis is a common feature in the peritoneal cavity with inflammation and fibrosis. In MGO models, VEGF-D was significantly increased in the diaphragm; however, VEGF-C was not significantly upregulated. Adeno-sVEGFR-3, which was detected on day 50 after administration via tail vein injections, successfully suppressed lymphangiogenesis in the diaphragm and parietal peritoneum in mouse MGO models without significant effects on fibrosis, inflammation, or neoangiogenesis. Drained volume in the peritoneal equilibration test using a 7.5% icodextrin peritoneal dialysis solution (the 7.5% icodextrin peritoneal equilibration test) was improved by Adeno-sVEGFR-3 on day 22 (P<0.05) and day 50 after reduction of inflammation (P<0.01), indicating that the 7.5% icodextrin peritoneal equilibration test identifies changes in lymphangiogenesis. The solute transport rate was not affected by suppression of lymphangiogenesis. In human peritoneal dialysis patients, the dialysate to plasma ratio of creatinine positively correlated with the dialysate VEGF-D concentration (P<0.001). VEGF-D mRNA was significantly higher in the peritoneal membranes of patients with ultrafiltration failure, indicating that VEGF-D is involved in the development of lymphangiogenesis in peritoneal dialysis patients. These results indicate that VEGFR-3 is a new target to improve net ultrafiltration by suppressing lymphatic absorption and that the 7.5% icodextrin peritoneal equilibration test is useful for estimation of lymphatic absorption.

Ionic conductivity of peritoneal dialysate: a new, easy and fast method of assessing peritoneal membrane function in patients undergoing peritoneal dialysis.

Peritoneal membrane function can be assessed using the peritoneal equilibration test (PET) and similar tests, but these are almost always complicated to use, require a considerable amount of working time and their results cannot always be easily interpreted. Ionic conductivity is a measure of the ability of an electrolyte solution to conduct electricity. We tested the hypothesis that the ionic conductivity of peritoneal dialysate can be used to evaluate peritoneal membrane function in peritoneal dialysis patients. We measured the ionic conductivity and classic biochemical parameters of peritoneal dialysate in 69 patients during a modified PET and compared their ability to evaluate peritoneal membrane function and to diagnose ultrafiltration failure (UFF). Ionic conductivity was correlated well with classical parameters of peritoneal transport as glucose reabsorption of glucose (D/D0: r(2) = 0.62, P < 0.0001) and creatinine transport (D/PCreat: r(2) = 0.72, P < 0.0001). Twelve patients (17%) experienced UFF and, in them, the ionic conductivity area under the receiver-operating characteristic curve was 0.91 (95% confidence interval: 0.81-0.96) with sensitivity of 1.00 and specificity of 0.84 at a cut-off value of 12.75 mS/cm. These findings indicate that the ionic conductivity of peritoneal dialysate can be used as a new screening tool to evaluate peritoneal membrane function.

Baseline higher peritoneal transport had been associated with worse nutritional status of incident continuous ambulatory peritoneal dialysis patients in Southern China: a 1-year prospective study.

The aim of the present study was to investigate the relationship between baseline peritoneal transport types and nutritional status in Chinese continuous ambulatory peritoneal dialysis (CAPD) patients. In the present single-centre, prospective study, incident CAPD patients were included from 15 April 2010 to 31 December 2011 and were followed up for 12 months. According to the results of baseline peritoneal equilibration test, patients were divided into lower peritoneal transport group (lower transporters) and higher peritoneal transport group (higher transporters). Nutritional status was evaluated by both subjective global assessment (SGA) and protein-energy wasting (PEW) score. The body composition parameters were assessed by body impedance analysis. A total of 283 CAPD patients were included in the study, of which 171 (60.4 %) were males with a mean age of 47.0 (sd 14.9) years. Compared with lower transporters (n 92), higher transporters (n 181) had lower levels of serum albumin (37.1 (sd 4.3) v. 39.6 (sd 4.3) g/l, P< 0.001), serum pre-albumin (356 (sd 99) v. 384 (sd 90) mg/l, P= 0.035), phase angle (6.15 (sd 0.39) v. 6.27 (sd 0.47)°, P< 0.05) and higher rate of malnutrition defined by SGA (52.5 v. 25.0%, P< 0.001) and PEW score (37.0 v. 14.1 %, P< 0.001) at 1-year of follow-up. Baseline higher peritoneal transport, analysed by multivariate binary logistic regressions, was independently associated with malnutrition (SGA mild to moderate and severe malnutrition: OR 3.43, 95% CI 1.69, 6.96, P< 0.01; PEW: OR 2.40, 95% CI 1.08, 5.31, P= 0.03). It was concluded that baseline higher peritoneal transport was independently associated with worse nutritional status of CAPD patients in Southern China.

Utilidad de la prueba de equilibrio peritoneal (PET) por volumen para estimar el tipo de peritoneo en los niños con diálisis peritoneal crónica

La prueba de equilibrio peritoneal (PET, por sus siglas en inglés) es el método convencional para conocer la permeabilidad de la membrana peritoneal y prescribir el tratamiento dialítico, identificando el tipo de transporte peritoneal por medio del volumen de drenado y la ultrafiltración neta. Para ello, se estudiaron 33 pacientes menores de 16 años con insuficiencia renal crónica (IRC), mediante PET estándar y por volumen drenado. El resultado será que en la PET el volumen promedio infundido fue de 1470 ml ± 450 ml, el drenado de 1720 ml ± 545.2 ml y el ultrafiltrado (UF) neto de 249.4 ml ± 147 ml. Con base en el UF neto y al índice de diálisis y en plasma (D/P) creatinina, el 45% al 36% tuvieron un transporte peritoneal alto. La UF durante el PET de 4 h fue de 275.8 ml ± 126.8 ml. El UF neto de la PET y la estancia de 4 h correlacionaron significativamente (p &lt; 0.05). Se concluye que, de acuerdo con el volumen de drenado, es posible conocer las características de transporte del peritoneo.

In Vivo Measurement of Site-Specific Peritoneal Solute Transport Using a Fiber-Optic-based Fluorescence Photobleaching Technique

Fluorescence recovery after photobleaching (FRAP) is a well-established method commonly used to measure the diffusion of fluorescent solutes and biomolecules in living cells or tissues. Here a fiber-optic-based FRAP (f-FRAP) system was developed, and validated using macromolecules in water and agarose gels of different concentrations. We applied f-FRAP to measure the site-specific diffusion of fluorescein (NaFluo) in peritoneal membranes (PMs) on the liver, cecum, and kidney of a living rat during peritoneal dialysis. Diffusion of fluorescein in PM varied in a time-dependent manner according to the type of organ (<TEX>$D_{PM\;on\;Liver}/D_{NaFluo}=0.199{\pm}0.085$</TEX>, <TEX>$D_{PM\;on\;Cecum}/D_{NaFluo}=0.292{\pm}0.151$</TEX>, <TEX>$D_{PM\;on\;Kidney}/D_{NaFluo}=0.218{\pm}0.110$</TEX>). The proposed method allows direct quantitative measurement of the three-dimensional diffusion in local PM in vivo, which was previously inaccessible by peritoneal function test methods such as peritoneal equilibration test (PET) and standardized PM assessment (SPA). f-FRAP is promising for local and dynamic assessments of peritoneal pathophysiology and the mass transport properties of PMs, presumed to be affected by variation of tissue structures over different organs and functional changes of the PM with years of peritoneal dialysis.

Rosiglitazone, a Peroxisome Proliferator-Activated Receptor (PPAR)-γ Agonist, Attenuates Inflammation Via NF-κB Inhibition in Lipopolysaccharide-Induced Peritonitis.

We assessed the anti-inflammatory effect of peroxisome proliferator-activated receptor (PPAR)-γ agonist, rosiglitazone, in a lipopolysaccharide (LPS)-induced peritonitis rat model. LPS was intraperitoneally injected into rats to establish peritonitis model. Male Sprague-Dawley (SD) rats were assigned to normal saline (the solvent of LPS), LPS, rosiglitazone plus LPS, and rosiglitazone alone. A simple peritoneal equilibrium test was performed with 20ml 4.25% peritoneal dialysis fluid. We measured the leukocyte count in dialysate and ultrafiltration volume. Peritoneal membrane histochemical staining was performed, and peritoneal thickness was assessed. CD40 and intercellular adhesion molecule-1 messenger RNA (ICAM-1 mRNA) levels in rat visceral peritoneum were detected by reverse transcription (RT)-PCR. IL-6 in rat peritoneal dialysis effluent was measured using enzyme-linked immunosorbent assay. The phosphorylation of NF-κB-p65 and IκBα was analyzed by Western blot. LPS administration resulted in increased peritoneal thickness and decreased ultrafiltration volume. Rosiglitazone pretreatment significantly decreased peritoneal thickness. In addition to CD40 and ICAM-1 mRNA expression, the IL-6, p-p65, and p-IκBα protein expressions were enhanced in LPS-administered animals. Rosiglitazone pretreatment significantly decreased ICAM-1 mRNA upregulation, secretion of IL-6 protein, and phosphorylation of NF-κB-p65 and IκBα without decreasing CD40 mRNA expression. Rosiglitazone has a protective effect in peritonitis, simultaneously decreasing NF-κB phosphorylation, suggesting that NF-κB signaling pathway mediated peritoneal inflammation induced by LPS. PPAR-γ might be considered a potential therapeutic target against peritonitis.

Influence of Peritoneal Transport Characteristics on Nutritional Status and Clinical Outcome in Chinese Diabetic Nephropathy Patients on Peritoneal Dialysis

Background:High peritoneal transport status was previously thought to be a poor prognostic factor in peritoneal dialysis (PD) patients. However, its effect on diabetic nephropathy PD patients is unclear in consideration of the adverse impact of diabetes itself. The purpose of this study was to investigate the influence of peritoneal transport characteristics on nutritional status and clinical outcome in diabetic nephropathy patients on PD.Methods:One hundred and two diabetic nephropathy patients on PD were enrolled in this observational cohort study. According to the initial peritoneal equilibration test result, patients were divided into two groups: Higher transport group (HT, including high and high average transport) and lower transport group (LT, including low and low-average transport). Demographic characteristics, biochemical data, dialysis adequacy, and nutritional status were evaluated. Clinical outcomes were compared. Risk factors for death-censored technique failure and mortality were analyzed.Results:Compared with LT group (n = 37), serum albumin was significantly lower and the incidence of malnutrition by subjective global assessment was significantly higher in HT group (n = 65) (P < 0.05). Kaplan–Meier analyses showed that death-censored technique failure and mortality were significantly increased in HT group compared with that in LT group. On multivariate Cox analyses, higher peritoneal transport status and lower residual renal function (RRF) were independent predictors of death-censored technique failure when adjusted for serum albumin and total weekly urea clearance (Kt/V). Independent predictors of mortality were advanced age, anemia, hypoalbuminemia, and lower RRF, but not higher peritoneal transport status.Conclusions:Higher peritoneal transport status has an adverse influence on nutrition for diabetic nephropathy patients on PD. Higher peritoneal transport status is a significant independent risk factor for death-censored technique failure, but not for mortality in diabetic nephropathy patients on PD.

Volume-Based Peritoneal Dialysis Prescription Guide to Achieve Adequacy Targets

♦ The use of automated and continuous ambulatory peritoneal dialysis (APD and CAPD) prescriptions (Rxs) to achieve adequate uremic toxin and fluid removal targets is important for attaining optimal patient outcomes. One approach for predicting such Rxs is the use of kinetic modeling. ♦ Demographic data and peritoneal membrane characteristics derived from a peritoneal equilibration test (PET) were available from 1,005 patients in North American centers who participated in a national adequacy initiative in 1999. Twelve patient subgroups were identified according to peritoneal membrane transport type and tertiles of total body water, assumed equal to urea distribution volume (Vurea). Each patient was then modeled using PD Adequest 2.0 to be treated by 12 CAPD and 34 APD Rxs using both glucose and icodextrin solutions to achieve adequacy targets of weekly urea Kt/V of 1.7 and 1 L of daily ultrafiltration (UF). Residual kidney function (RKF) was assumed to be 0, 2, 4, and 6 mL/min. Feasible peritoneal dialysis (PD) Rxs were identified where: 1) the 95% confidence limit achieved the goal of meeting the targets for urea Kt/V, daily UF, and both in 85%, 75%, and 70% of patients, respectively; 2) average PD solution dextrose concentration was < 2.5%; and 3) the number of daytime exchanges was minimized. ♦ Feasible PD Rxs were similar when RKF was ≥ 2 mL/min, allowing condensed recommendations based on RKF ≥ 2 mL/min or < 2 mL/min. Individuals with lower or slower membrane transport required relatively greater 24-h solution volumes to achieve adequacy targets when RKF fell below 2 mL/min. With increasing Vurea, there was disproportionately greater dependence on RKF to achieve targets. While multiple Rxs achieving urea Kt/V and daily UF goals were identified for all membrane transport types, use of icodextrin in the long dwell reduced the need for a midday exchange in APD, glucose exposure, required fill and 24-h dwell volumes, irrespective of RKF and Vurea. While these benefits were most notable in high and high-average transporters, similar results were also seen in low and low-average transporters. ♦ Kinetic modeling identified multiple APD and CAPD Rxs that achieved adequate uremic solute and fluid removal for patients, irrespective of RKF and Vurea. Use of icodextrin rather than glucose in the long dwell reduced the complexity of the PD regimen, total glucose exposure, and 24-h total treatment solution volumes. Irrespective of modeling, adequacy of any PD prescription should be based upon individual clinical evaluation both for volume and solute removal.

Low molecular weight heparin (LMWH) improves peritoneal function and inhibits peritoneal fibrosis possibly through suppression of HIF-1α, VEGF and TGF-β1.

BackgroundPeritoneal fibrosis is the major cause of ultrafiltration failure, and intraperitoneal administration of Low Molecular Weight Heparin (LMWH) was reported to protect peritoneal function. But the exact mechanism of its influence on peritoneal structure and function is still unknown.MethodsA fibrosis model of rat was established by intraperitoneal (IP) administration of PD fluid and Erythromycin Lactobionate. Fifty-two rats were randomly divided into 6 groups: (1) normal control group (CON, n = 6); (2) normal saline group (NS, n = 10); (3) high-glucose group (GLU, n = 10); (4) heparin group (HEP, n = 6); (5) low dose LMWH group (LLMWH, n = 10); (6) high dose LMWH group (HLMWH, n = 10). Two hour peritoneal equilibration test was performed after 28 days of intervention. The peritoneum, mesentery and omentum were harvested, and evaluated by Hematoxylin-Eosin and Masson Trichrome staining. The expressions of HIF-1α, VEGF and TGF-β1 in parietal peritoneum were detected by IHC and RT-PCR (Reverse Transcriptase Polymerase Chain Reaction).ResultsCompared with group CON and NS, ultrafiltration volume and D2/D0 glucose in group GLU decreased significantly, D/Purea (Dialysate-Plasma ratio of urea), D/Palb (Dialysate-Plasma ratio of albumin), peritoneal thickness, neoangiogenesis and inflammatory reaction increased significantly (all P<0.05). Administration of heparin and LMWH markedly alleviated these above pathological changes. The protein and mRNA levels of HIF-1α, VEGF and TGF-β1 increased significantly in group GLU, and decreased significantly after administration of LMWH in a dose-dependent manner.ConclusionsLMWH ameliorates peritoneal function and inhibits peritoneal fibrosis, possibly through suppression of HIF-1α, VEGF and TGF-β1.

The Fast Peritoneal Equilibration Test First and Second Hour Results

Abstract Introduction. The Peritoneal Equilibration Test (PET) is employed to assess peritoneal membrane transport function. The purpose of the test is to determine the optimal peritoneal dialysis regimen. The performance of the test, which is conducted over 4 hours, is time consuming both for the nurses and the patient. There have been studies to validate an approved short version of the original PET protocol, and all have yielded different results. We evaluated the concordance between the 1-hour, 2-hour and 4-hour (classical) test results of the fast PET. Methods. The study included 32 patients (20 males and 12 females). The patients underwent the 4-hour fast PET test, and the dialysate-to-plasma ratio of creatinine concentration (D/Pcrea) was determined. The standard deviation was added to or subtracted from the mean D/Pcrea ratios at hours 1, 2, and 4 to determine transport groups. Results. The mean age of the patients was 51.4±16.7 years. Mean D/Pcrea ratios at hours 1, 2, and 4 were 0.41±0.07, 0.54±0.10, and 0.69+0.12, respectively. There was a strong correlation between the 4-hour D/Pcrea ratio and 1-hour (r=0.756, p&lt;0.001) and 2-hour (r=0.867, p&lt;0.001) D/Pcrea ratios. Seventeen patients (53%) were in the same transport group at hours 1, 2, and 4. Eighteen patients (56%) at 1 hour and 24 patients (75%) at 2 hours fell into the same transport group at 4 hours. The patients that fell into different transport groups at different time points showed a shift to a lower or higher transport group. Conclusions. Two-hour fast PET gives promising results for clinical assessment purposes.

Interstitial Fibrosis Restricts Osmotic Water Transport in Encapsulating Peritoneal Sclerosis.

Encapsulating peritoneal sclerosis (EPS) is a rare but severe complication of peritoneal dialysis (PD) characterized by extensive fibrosis of the peritoneum. Changes in peritoneal water transport may precede EPS, but the mechanisms and potential predictive value of that transport defect are unknown. Among 234 patients with ESRD who initiated PD at our institution over a 20-year period, 7 subsequently developed EPS. We evaluated changes in peritoneal transport over time on PD in these 7 patients and in 28 matched controls using 3.86% glucose peritoneal equilibration tests. Compared with long-term PD controls, patients with EPS showed early loss of ultrafiltration capacity and sodium sieving before the onset of overt EPS. Multivariate analysis revealed that loss of sodium sieving was the most powerful predictor of EPS. Compared with long-term PD control and uremic peritoneum, EPS peritoneum showed thicker submesothelial fibrosis, with increased collagen density and a greater amount of thick collagen fibers. Reduced osmotic conductance strongly correlated with the degree of peritoneal fibrosis, but not with vasculopathy. Peritoneal fibrosis was paralleled by an excessive upregulation of vascular endothelial growth factor and endothelial nitric oxide synthase, but the expression of endothelial aquaporin-1 water channels was unaltered. Our findings suggest that an early and disproportionate reduction in osmotic conductance during the course of PD is an independent predictor of EPS. This functional change is linked to specific alterations of the collagen matrix in the peritoneal membrane of patients with EPS, thereby validating the serial three-pore membrane/fiber matrix and distributed models of peritoneal transport.

Expression of aquaporin-1 in human peritoneum and its effect on peritoneal dialysis patients with the different peritoneal transport characteristics

Objective To investigate the expression of aquaporin-1 (AQP1) in human peritoneum and its effect on peritoneal dialysis (PD) patients with the different peritoneal transport characteristics. Methods Peritoneal biopsies were obtained from the PD patients (n=30) at catheter insertion. Western blot and immunohistochemical staining were used to investigate AQP1 expression in peritoneal tissues. After catheter insertion, 4 week, peritoneal equilibrium test (PET) was used to decide peritoneal transport characteristics. Results Western blot revealed a major band at 28 kDa band. The expression of AQP1 index was 1.49±0.67 in the normal subjects, and 1.61±0.76 in the PD patients, and there was no significant difference. Positive deposition was distributed in mesothelial cells, endothelial cells of capillaries, and small veins. The index of AQP1 expression in endothelial cells of capillaries in normal subjects and PD patients were 2.12±0.18, and 2.50±0.81, respectively, and no significant difference was found. The index of AQP1 expression in mesothelial cells of capillaries in normal subjects and PD patients were 1.95±0.67, and 2.23±1.07, respectively, and no significant difference was found. Among PD patients, the level of AQP1 was significantly different. Conclusions The expression of AQP1 was different in the PD patients with different peritoneal transport characteristics. In the high and high average transport groups, the level of AQP1 was lower; the low transport group was higher. It reveals that AQP1 plays a role in the pathogenesis of transcellular water transport. Key words: Aquaporins/biosynthesis; Peritoneal dialysis; Peritoneum/metabolism; Immunohistochemistry; Blotting, Western

The importance of ultrasonographic measurement of peritoneal wall thickness in pediatric chronic peritoneal dialysis patients

Loss of peritoneal function due to peritoneal fibrosing syndrome (PFS) is a major factor leading to treatment failure in chronic peritoneal dialysis (PD) patients. Although the precise biologic mechanisms responsible for these changes have not been defined, the general assumption is that alterations in peritoneal function are related to structural changes in the peritoneal membrane. Studies of the peritoneal membrane by non-invasive ultrasonography (US) in chronic PD patients are limited. The aim of the present study is to assess the relationship between functional parameters of peritoneum and peritoneal thickness measured by US in children treated by chronic PD. We recruited two groups of patients: 23 subjects (13 females, 10 males) on chronic PD (patient group) and 26 (7 females, 19 males) on predialysis out-patient follow-up (creatinine clearance: 20–60 mL/min/1.73 m2) (control group). Age, sex, weight, height, body mass index (BMI), chronic PD duration, episodes of peritonitis and the results of peritoneal equilibration test (PET) were recorded. Hemoglobin (Hb), blood pressure (BP), left ventricular mass index (LVMI) and renal osteodystrophy (ROD) parameters were also obtained. The thickness of the parietal peritoneum was measured by trans-abdominal US in all children. Statistical analyses were performed by using Student's t and Pearson's correlation tests. Mean peritoneal thickness in chronic PD patients (1028.26 ± 157.26 μm) was significantly higher than control patients (786.52 ± 132.33). Mean peritoneal thickness was significantly correlated with mean body height (R2 = 0.93, p < 0.05), BMI (R2 = 0.25, p < 0.05), chronic PD duration (R2 = 0.64, p < 0.05), episodes of peritonitis (R2 = 0.93, p < 0.05), D/Pcreatinine (R2 = 0.76, p < 0.05) and D4/D0glucose (R2 = 0.81, p < 0.05). No correlation was found between peritoneal thickness and Hb, BP, LVMI and ROD parameters. In conclusion, ultrasonographic measurement of peritoneal membrane thickness is a simple and non-invasive method in chronic PD children. This diagnostic tool likely enables to assess peritoneal structure and function in these patients.

Effluent Tenascin-C Levels Reflect Peritoneal Deterioration in Peritoneal Dialysis: MAJOR IN PD Study

Peritoneal deterioration causing structural changes and functional decline is a major complication of peritoneal dialysis (PD). The aim of this study was to explore effluent biomarkers reflecting peritoneal deterioration. In an animal study, rats were intraperitoneally administered with PD fluids adding 20 mM methylglyoxal (MGO) or 20 mM formaldehyde (FA) every day for 21 days. In the MGO-treated rats, tenascin-C (TN-C) levels in the peritoneal effluents were remarkably high and a cluster of TN-C-positive mesothelial cells with epithelial-to-mesenchymal transition- (EMT-) like change excessively proliferated at the peritoneal surface, but not in the FA-treated rats. Effluent matrix metalloproteinase-2 (MMP-2) levels increased in both the MGO- and FA-treated rats. In a clinical study at 18 centers between 2006 and 2013, effluent TN-C and MMP-2 levels were quantified in 182 PD patients with end-stage renal disease. Peritoneal function was estimated using the peritoneal equilibration test (PET). From the PET results, the D/P Cr ratio was correlated with effluent levels of TN-C (ρ = 0.57, p < 0.001) and MMP-2 (ρ = 0.73, p < 0.001). We suggest that TN-C in the effluents may be a diagnostic marker for peritoneal deterioration with EMT-like change in mesothelial cells in PD.

Peritoneal Dialysis in Western Countries

Background: Peritoneal dialysis (PD) for the treatment of end-stage renal failure was introduced in the 1960s. Nowadays it has evolved to an established therapy that is complementary to hemodialysis (HD), representing 11% of all patients treated worldwide with dialysis. Despite good clinical outcomes and similar results in patient survival between PD and HD, the penetration of PD is decreasing in the Western world. Summary: First the major events in the history of the development of PD are described. Then important insights into the physiology of peritoneal transport are discussed and linked to the changes in time observed in biopsies of the peritoneal membrane. Furthermore, the developments in peritoneal access, more biocompatible dialysate solutions, automated PD at home, the establishment of parameters for dialysis adequacy and strategies to prevent infectious complications are mentioned. Finally non-medical issues responsible for the declining penetration in the Western world are analyzed. Key Messages: Only after introduction of the concept of continuous ambulatory PD by Moncrief and Popovich has this treatment evolved in time to a renal replacement therapy. Of all structures present in the peritoneal membrane, the capillary endothelium offers the rate-limiting hindrance for solute and water transport for the diffusive and convective transport of solutes and osmosis. The functional and anatomical changes in the peritoneal membrane in time can be monitored by the peritoneal equilibrium test. Peritonitis incidence decreased by introduction of the Y-set and prophylaxis using mupirocin on the exit site. The decrease in the proportion of patients treated with PD in the Western world can be explained by non-medical issues such as inadequate predialysis patient education, physician experience and training, ease of HD initiation, overcapacity of in-center HD, lack of adequate infrastructure for PD treatment, costs and reimbursement issues of the treatment. Facts from East and West: (1) PD is cheaper than HD and provides a better quality of life worldwide, but its prevalence is significantly lower than that of HD in all countries, with the exception of Hong Kong. Allowing reimbursement of PD but not HD has permitted to increase the use of PD over HD in many Asian countries like Hong Kong, Vietnam, Taiwan, Thailand, as well as in New Zealand and Australia over the last years. In the Western world, however, HD is still promoted, and the proportion of patients treated with PD decreases. Japan remains an exception in Asia where PD penetration is very low. Lack of adequate education of practitioners and information of patients might as well be reasons for the low penetration of PD in both the East and West. (2) Patient survival of PD varies between and within countries but is globally similar to HD. (3) Peritonitis remains the main cause of morbidity in PD patients. South Asian countries face specific issues such as high tuberculosis and mycobacterial infections, which are rare in developed Asian and Western countries. The infection rate is affected by climatic and socio-economic factors and is higher in hot, humid and rural areas. (4) Nevertheless, the promotion of a PD-first policy might be beneficial particularly for remote populations in emerging countries where the end-stage renal disease rate is increasing dramatically.

Increased peritoneal permeability at peritoneal dialysis initiation is a potential cardiovascular risk in patients using biocompatible peritoneal dialysis solution.

BackgroundCardiovascular disease is a frequent cause of death in peritoneal dialysis patients. Biocompatible peritoneal dialysis solutions with neutral pH have been anticipated to reduce cardiovascular disease more than conventional peritoneal dialysis solutions with low pH, but it remains unclear which factors at peritoneal dialysis initiation increase cardiovascular risk in patients using biocompatible peritoneal dialysis solutions. This study was undertaken to investigate which clinical factors at peritoneal dialysis initiation, including peritoneal transport status, are associated with cardiovascular event in patients using biocompatible peritoneal dialysis solution.MethodsThis retrospective cohort study of peritoneal dialysis patients using biocompatible solutions with neutral pH assessed relations of clinical parameters at peritoneal dialysis initiation to cardiovascular event during the subsequent five years.ResultsOf 102 patients who started peritoneal dialysis, cardiovascular event occurred in 18. Age, history of cardiovascular disease before peritoneal dialysis initiation, hemoglobin, serum albumin, C-reactive protein, peritoneal permeability defined by the ratio of dialysate to plasma creatinine concentration at 4 hr (D/Pcre) in peritoneal equilibration test (PET), number of patients in each PET category defined by D/Pcre, and peritoneal protein clearance significantly differed between patients with and without cardiovascular event. For patients divided according to PET category using Kaplan–Meier method, the group of high average to high peritoneal transporters exhibited significantly high incidence of cardiovascular event and mortality compared with the groups of low and low-average peritoneal transporters (Log rank; p = 0.0003 and 0.005, respectively). A Cox proportional hazards model showed independent association of PET category classification with cardiovascular event.ConclusionsPeritoneal permeability expressed as PET category at peritoneal dialysis initiation is an independent cardiovascular risk factor in peritoneal dialysis patients using biocompatible peritoneal dialysis solution with neutral pH. Greater peritoneal permeability at peritoneal dialysis initiation might reflect subclinical vascular disorders.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2369-15-173) contains supplementary material, which is available to authorized users.