Conventional Peritoneal Dialysis Solutions Research Articles

Predictors of encapsulated peritoneal sclerosis in patients undergoing peritoneal dialysis using neutral-pH dialysate.

Encapsulated peritoneal sclerosis (EPS) is a serious complication in patients undergoing peritoneal dialysis (PD). Neutral-pH dialysate is associated with less peritoneal damage and a lower incidence of EPS than conventional PD solution. However, monitoring for peritoneal damage and predicting EPS remain important during PD therapy. We measured the mesothelial cell area, dialysate-to-plasma ratio of creatinine after 4h, and concentrations of the potential biological markers effluent fibrin degradation products (eFDPs), cancer antigen-125, and interleukin-6 in the effluent dialysate from patients who had been undergoing PD therapy for > 5years in our hospital. These biomarkers were obtained from the drainage fluid of the final measurement of peritoneal equilibration testing before withdrawal from PD therapy. The concentrations of these potential biomarkers were measured in 39 patients who withdrew from PD therapy and were enrolled in the study. Three participants developed EPS after withdrawing PD. The dialysate-to-plasma ratio of creatinine, area of mesothelial cells, and interleukin-6 appearance rate in participants who developed EPS tended to be higher than those in patients who did not, but there were no significant differences. Significantly more eFDPs were in participants who developed EPS than in those who did not (138.5 ± 15.1 vs. 32.9 ± 7.4µg/mL, P = 0.002). There was no difference in the cancer antigen-125 appearance rate between the groups. A cut-off value of eFDPs ≥ 119.1µg/mL was optimal for predicting EPS (P = 0.006, specificity = 0.972, sensitivity = 1.000). This study shows that eFDPs may be a useful biological marker for predicting EPS in patients undergoing PD using neutral-pH dialysate.

#2490 Analyzing the morphology of mesothelial cells when exposed to peritoneal dialysis solutions

Abstract Background and Aims Glucose remains the predominant osmotic agent in peritoneal dialysis (PD), yet its prolonged use is associated with an inevitable decline in peritoneal filtration capacity. Persistent contact with glucose during dialysis can induce significant morphological and functional changes in the peritoneum. In this study, we explore the morphological alterations in mesothelial cells exposed to both conventional glucose-based PD solutions and an innovative biocompatible PD solution (XyloCore) containing L-carnitine and Xylitol. Method Met5A mesothelial cells were seeded and cultured on a polyester filter (with a pore size of 0.4 micrometers, Transwell, 12 well type, Millipore) utilizing a full medium. The impact of PD solutions, differentiating between glucose-based and XyloCore, was assessed on cells cultivated on transwells. These cells were exposed to PD solutions on the apical side and to culture medium on the basal side. The cells were then employed for proteomic and metabolomic assessments and were also fixed and scrutinized through scanning electron microscopy (SEM). Results Through unsupervised hierarchical clustering analysis, discernable proteomic distinctions emerged between wild-type (WT) cells (control) and cells exposed to either glucose-based PD solution or XyloCore. In SEM analysis, control cells exhibited a distinct flat epithelial appearance. Contrastingly, subjecting WT cells to treatment with a glucose-based PD solution induced significant alterations in cellular morphology. Notably, cells displayed elongated shapes, loosening of cell-cell contacts, and a consistent denuding of the culture surface. In contrast, XyloCore maintained a better cellular morphology and mitigated cell detachment. Conclusion Preserving the integrity of the mesothelial barrier is crucial for maintaining peritoneal ultrafiltration capacity. The findings suggest that glucose-based PD solutions trigger early morphological changes in cell shape and cell-cell contacts, likely stemming from alterations in cytoskeleton or adhesion molecules. The exploration of new osmotic agents in clinical practice holds paramount significance for the future of peritoneal dialysis.

The benefits of peritoneal dialysis (PD) solution with low-glucose degradation product in residual renal function and dialysis adequacy in PD patients: A meta-analysis.

The peritoneal effects of low-glucose degradation product (GDP)-containing peritoneal dialysis (PD) solutions have been extensively described. To systematically evaluate the efficacy and safety of low GDP solution for PD patients, specifically the effect on residual renal function (RRF) and dialysis adequacy, we conducted a meta-analysis of the published randomized controlled trials (RCTs). Different databases were searched for RCTs that compared low GDP-PD solutions with conventional PD solutions in the treatment of PD patients with continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD). The outcomes of RCTs should include RRF and may include small solute clear-ance, peritoneal transport status, nutritional status, and all-cause mortality. Seven studies (632 patients) were included. Compared with the conventional solution, low-GDP solution preserved RRF in PD patients over time (MD 0.66 mL/min, 95% CI 0.34 to 0.99; p<0.0001), particularly in one year of treatment (p<0.01), and improved weekly Kt/V (MD 0.11, 95% CI 0.05 to 0.17; p=0.0007) without an increased 4-hour D/Pcr (MD 0.00, 95% CI -0.02 to 0.02; p=1.00). Notably, the MD of RRF and urine volume between the two groups tended to decrease as time on PD progressed up to 24 months. Patients using low GDP PD solutions did not have an increased risk of all-cause mortality (MD 0.97, 95% CI 0.50 to 1.88; p=0.93). Our meta-analysis confirms that the low GDP PD solution preserves RRF, improves the dialysis adequacy without increasing the peritoneal solute transport rate and all-cause mortality. Further trials are needed to deter-mine whether this beneficial effect can affect long-term clinical outcomes.

P1130A CELLULAR MODEL OF HUMAN MESOTHELIUM TO STUDY OF WATER TRANSPORT DURING PERITONEAL DIALYSIS AND THE BIOCOMPATIBILITY OF INNOVATIVE GLUCOSE-SPARING SOLUTIONS.

Abstract Background and Aims The three pore model postulates that the endothelium of peritoneal capillaries is the major limiting barrier regulating water transport across peritoneal membrane during peritoneal dialysis (PD). We hypothesize that the mesothelium may represent an additional selective barrier to water diffusion in PD. We previously demonstrated that the water channel AQP1 is expressed in vivo by mesothelial cells. Here, we characterized an immortalized cell line of human mesothelium (HMC) to study the functional role of the water channel AQP1 in mediating water transport during PD and also to test the biocompatibility of glucose-sparing PD solutions (Xylocore), containing xylitol and L-carnitine as the main osmotic agents. Method Cells were grown onto porous cell culture inserts to achieve polarization. Polarization was demonstrated by expression of the tight junction markers Zo-1 and occludin. Transepithelial water transport was measured by TEA+-sensitive microelectrodes. HMC cell monolayers were exposed to PD solutions at the apical side for 8 hours. The biocompatibility of conventional versus innovative PD solutions was evaluated by MTT-test, measurement of transepithelial electrical resistance (TEER) and production of pro-inflammatory cytokines by by Luminex xMAP technology. Results HMC cells showed polarized expression of Na+/K+-ATPase and tight junctions markers but no endogenous expression of AQP1. HMC showed a low TEER (40Ω/cm2) compared to renal cells not expressing AQP1(1000Ω/cm2). However, the transepithelial water transport was comparable between the two cell types. Experiments in HMCs transfected with AQP1 cDNA, suggested that the water permeability of HMC was increased by two-fold in the presence of AQP1. Biocompatibility assays indicated that in conventional dialysis solutions glucose concentration decreased cell viability in a dose-dependent manner. Glucose concentration also strongly decreased the TEER, suggesting reduction of the barrier integrity, and increased pro-inflammatory cytokines production. Interestingly, substitution of part of the glucose with xylitol and L-carnitine minimized these effects. Conclusion These results suggest that the mesothelium may represent an additional selective barrier regulating water transport through the water channel AQP1 in PD. Importantly, we also demonstrate that the formulation of glucose-sparing PD solutions containing xylitol and L-carnitine better preserve mesothelial cells viability and may represent a useful means to prolong the dialysis life of patients undergoing peritoneal dialysis.

Vasculopathy plays an important role during the development and relapse of encapsulating peritoneal sclerosis with conventional peritoneal dialysis solutions.

Encapsulating peritoneal sclerosis (EPS) is an uncommon but life-threatening complication of peritoneal dialysis (PD) therapy. The causative factors of EPS remain unclear. Pathological studies of the peritoneum affected by EPS and relationships with clinical factors including PD solutions remain lacking. The objective of this study was to examine peritoneal samples from EPS patients and to identify the associations of peritoneal pathology with different clinical factors. Peritoneal specimens were obtained at the time of surgical enterolysis in Tsuchiya General Hospital from 1993 to 2016. A total of 223 PD patients were enrolled and analyzed. Tissues were fixed with formalin and processed with hematoxylin and eosin and Masson's trichrome staining, as well as immunohistochemical staining for CD31 and CD68. Evaluations could be made in 174 patients who received surgical enterolysis. Conventional or pH-neutral low-glucose degradation product PD solutions were utilized during PD treatment. The conventional PD solution group showed less angiogenesis (P = 0.013) but more severe vasculopathy, in the form of a lower ratio of luminal diameter to vessel diameter (L/V ratio) (P < 0.001) in association with longer PD treatment. Multivariate Cox proportional hazard models revealed that L/V ratio (per 0.1 increase, hazard ratio = 0.88, 95% confidence interval 0.77-0.99, P = 0.047) was significantly associated with a lower incidence of EPS relapse. In contrast, most of the cases in the pH-neutral solution group showed milder vasculopathy. The pathology of EPS differed between conventional and pH-neutral solution groups. Vasculopathy was related to the development and relapse of EPS in the conventional solution group.

A cellular model of human mesothelium to study the physiology of water transport during peritoneal dialysis and the biocompatibility of innovative glucose‐sparing solutions.

The three pore model postulates that the endothelium of peritoneal capillaries is the major limiting barrier regulating water transport across peritoneal membrane during peritoneal dialysis (PD).We hypothesize that the mesothelium may represent an additional selective barrier to water diffusion in PD.We characterized an immortalized cell line of human mesothelium (HMC) to study the functional role of the water channel AQP1 expressed in vivo by mesothelial cells and also to test the biocompatibility of glucose‐sparing PD solutions containing xylitol and carnitine as the main osmotic agents.Transepithelial water transport was measured by TEA+‐sensitive microelectrodes. The biocompatibility of conventional versus innovative PD solutions was evaluated by MTT‐test, measurement of transepithelial electrical resistance (TEER) and production of pro‐inflammatory cytokines.HMCs showed polarized expression of Na+/K+‐ATPase and tight junctions markers but no endogenous expression of AQP1.HMC showed a low TEER compared to renal cells not expressing AQP1. However, the transepithelial water transport was comparable between the two cell types.Experiments in HMCs transfected with AQP1 cDNA, suggest that the water permeability of HMC is strictly dependent of the presence of AQP1.Biocompatibility assays indicate that conventional dialysis solutions with high glucose significantly reduce both cell viability and TEER, and increase pro‐inflammatory cytokines production.Interestingly, innovative PD solutions minimize these effects. These results suggest that the mesothelium may represent an additional selective barrier regulating water transport in PD. Importantly, we also demonstrated that the formulation of glucose‐sparing PD solutions containing xylitol and carnitine better preserve mesothelial cells viability and may represent a useful means to prolong the dialysis life of patients undergoing peritoneal dialysis.Support or Funding InformationApulian Region NATURe project Code: XUANRO4

Removal of Protein-Bound Uremic Toxins by Liposome-Supported Peritoneal Dialysis.

Background:Protein-bound uremic toxins (PBUTs) are poorly cleared by peritoneal dialysis (PD). This study aimed to enhance PBUT removal in PD by adding a binder to the peritoneal dialysate and to evaluate the feasibility and efficacy of liposome-supported PD (LSPD) to increase the removal of PBUTs compared with albumin PD.Methods:Removal of p-cresyl sulfate (PCS), indoxyl sulfate (IS), and indole-3-acetic acid (3-IAA) was first evaluated in an in vitro PD model using artificial plasma preloaded with test solutes. Male Sprague-Dawley rats (n = 24) were then subjected to 5/6 nephrectomy and fed for 16 weeks to establish end-stage renal failure, after which they were treated with either conventional glucose-based PD, albumin-based PD, or liposome-based PD. Removal of PBUTs and small water-soluble solutes was determined during a 6-hour PD dwell.Results:In vitro experiments showed that adding albumin as a toxin binder to the dialysate markedly increased the removal of PCS, IS, and 3-IAA compared with the control. The uptake capacity of liposomes was comparable with that of albumin for PCS and 3-IAA, though slightly inferior for IS. In vivo PD in uremic rats demonstrated that LSPD resulted in higher intraperitoneal concentrations and more total mass removal for PBUTs than the conventional glucose-based PD, which was comparable with albumin PD.Conclusions:Supplementing conventional glucose-based PD solutions with a binder could efficiently increase the removal of PBUTs. This preliminary study suggested that LSPD may be a promising alternative to albumin PD for increasing PBUT removal in the development of next-generation PD solutions for PD patients.

The role of icodextrin in peritoneal dialysis: protocol for a systematic review and meta-analysis

BackgroundPrevious meta-analyses have found several advantages of icodextrin compared with glucose in the application of peritoneal dialysis (PD), such as an improvement of peritoneal ultrafiltration during the long dwell and a reduction in episodes of uncontrolled fluid overload. However, the effect of icodextrin on patient-relevant outcomes remains unclear. This review aims to evaluate the benefits and harms of icodextrin in comparison with conventional glucose PD solution in patients with end-stage kidney disease receiving PD.MethodsRandomized controlled trials of icodextrin comparing with conventional glucose solution in patients with end-stage kidney disease who received PD will be deemed eligible. We will conduct systematic searches in MEDLINE, EMBASE, CENTRAL, Ichushi-Web, Chinese and Japanese databases, and in clinical trials registries (ClinicalTrials.gov, International Clinical Trials Registry Platform Search Portal (ICTRP), EU Clinical Trials Register, Japan Registries Network (JPRN), China’s Clinical Trial Registry (ChiCTR)). Furthermore, we will check conference proceedings and search references from relevant studies manually. Relevant pharmaceutical companies, authors, and experts will be contacted in an effort to identify further studies. We will not apply any limitations regarding language, publication status, and publication date when searching for eligible studies. The selection of studies, data extraction, and risk of bias assessment will be carried out by two independent reviewers. Data synthesis will be performed using RevMan 5 software with either a fixed effects model or random-effects model, depending on the presence of heterogeneity. For the assessment of statistical heterogeneity, I2 will be calculated. Sources of clinical heterogeneity will be evaluated through subgroup analyses. If there are ten or more studies included in the meta-analysis, we will investigate the publication bias using funnel plots and Egger’s test. The quality of the body of evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system.DiscussionWe assume that our systematic review will be more comprehensive compared to those published previously due to contacting the relevant pharmaceutical companies and a systematic search of published and unpublished non-English studies from China, Taiwan, and Japan.Systematic review registrationPROSPERO CRD42018096951

Biocompatible dialysis fluids for peritoneal dialysis.

Biocompatible peritoneal dialysis (PD) solutions, including neutral pH, low glucose degradation product (GDP) solutions and icodextrin, have previously been shown to favourably influence some patient-level outcomes, albeit based on generally sub-optimal quality studies. Several additional randomised controlled trials (RCT) evaluating biocompatible solutions in PD patients have been published recently. This is an update of a review first published in 2014. This review aimed to look at the benefits and harms of biocompatible PD solutions in comparison to standard PD solutions in patients receiving PD. The Cochrane Kidney and Transplant Specialised Register was searched up to 12 February 2018 through contact with the Information Specialist using search terms relevant to this review. Studies in the Specialised Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register Search Portal and ClinicalTrials.gov. All RCTs and quasi-RCTs in adults and children comparing the effects of biocompatible PD solutions (neutral pH, lactate-buffered, low GDP; neutral pH, bicarbonate(± lactate)-buffered, low GDP; glucose polymer (icodextrin)) in PD were included. Studies of amino acid-based solutions were excluded. Two authors extracted data on study quality and outcomes. Summary effect estimates were obtained using a random-effects model, and results were expressed as risk ratios and 95% confidence intervals (CI) for categorical variables, and mean differences (MD) or standardised mean differences (SMD) and 95% CI for continuous variables. This review update included 42 eligible studies (3262 participants), including six new studies (543 participants). Overall, 29 studies (1971 participants) compared neutral pH, low GDP PD solution with conventional PD solution, and 13 studies (1291 participants) compared icodextrin with conventional PD solution. Risk of bias was assessed as high for sequence generation in three studies, allocation concealment in three studies, attrition bias in 21 studies, and selective outcome reporting bias in 16 studies.Neutral pH, low GDP versus conventional glucose PD solutionUse of neutral pH, low GDP PD solutions improved residual renal function (RRF) preservation (15 studies, 835 participants: SMD 0.19, 95% CI 0.05 to 0.33; high certainty evidence). This approximated to a mean difference in glomerular filtration rate of 0.54 mL/min/1.73 m2 (95% CI 0.14 to 0.93). Better preservation of RRF was evident at all follow-up durations with progressively greater preservation observed with increasing follow up duration. Neutral pH, low GDP PD solution use also improved residual urine volume preservation (11 studies, 791 participants: MD 114.37 mL/day, 95% CI 47.09 to 181.65; high certainty evidence). In low certainty evidence, neutral pH, low GDP solutions may make little or no difference to 4-hour peritoneal ultrafiltration (9 studies, 414 participants: SMD -0.42, 95% CI -0.74 to -0.10) which approximated to a mean difference in peritoneal ultrafiltration of 69.72 mL (16.60 to 122.00 mL) lower, and may increase dialysate:plasma creatinine ratio (10 studies, 746 participants: MD 0.01, 95% CI 0.00 to 0.03), technique failure or death compared with conventional PD solutions. It is uncertain whether neutral pH, low GDP PD solution use led to any differences in peritonitis occurrence, hospitalisation, adverse events (6 studies, 519 participants) or inflow pain (1 study, 58 participants: RR 0.51, 95% CI 0.24 to 1.08).Glucose polymer (icodextrin) versus conventional glucose PD solutionIn moderate certainty evidence, icodextrin probably reduced episodes of uncontrolled fluid overload (2 studies, 100 participants: RR 0.30, 95% CI 0.15 to 0.59) and augmented peritoneal ultrafiltration (4 studies, 102 participants: MD 448.54 mL/d, 95% CI 289.28 to 607.80) without compromising RRF (4 studies, 114 participants: SMD 0.12, 95% CI -0.26 to 0.49; low certainty evidence) which approximated to a mean creatinine clearance of 0.30 mL/min/1.73m2 higher (0.65 lower to 1.23 higher) or urine output (3 studies, 69 participants: MD -88.88 mL/d, 95% CI -356.88 to 179.12; low certainty evidence). It is uncertain whether icodextrin use led to any differences in adverse events (5 studies, 816 participants) technique failure or death. This updated review strengthens evidence that neutral pH, low GDP PD solution improves RRF and urine volume preservation with high certainty. These effects may be related to increased peritoneal solute transport and reduced peritoneal ultrafiltration, although the evidence for these outcomes is of low certainty due to significant heterogeneity and suboptimal methodological quality. Icodextrin prescription increased peritoneal ultrafiltration and mitigated uncontrolled fluid overload with moderate certainty. The effects of either neutral pH, low GDP solution or icodextrin on peritonitis, technique survival and patient survival remain uncertain and require further high quality, adequately powered RCTs.

Associations Between Peritoneal Glucose Exposure, Glucose Degradation Product Exposure, and Peritoneal Membrane Transport Characteristics in Peritoneal Dialysis Patients: Secondary Analysis of the balANZ Trial.

Glucose is the most commonly used osmotic medium in peritoneal dialysis (PD) solutions, and its use has been associated with both local and systemic adverse effects. Previous, single-center, observational cohort studies have reported conflicting findings regarding whether a relationship exists between peritoneal glucose exposure and peritoneal small solute transport rate. In this secondary analysis of the balANZ multicenter, multinational, randomized controlled trial of a neutral pH, ultra-low glucose degradation product (biocompatible) versus conventional PD solutions over a 2-year period, the relationship between time varying peritoneal glucose exposure and change in peritoneal solute transport rate, (measured as dialysate to plasma creatinine ratio at 4 hours [D:PCr4h]), was evaluated using multivariable, multilevel linear regression. Baseline peritoneal glucose exposure was also assessed as either a continuous or categorical variable. The study included 165 patients (age 58.1 ± 14.2 years, 55% male, 33% diabetic). Peritoneal glucose exposure increased over time (coefficient 1.49, 95% confidence interval [CI] 1.07 - 1.92 and was not significantly associated with change in D:PCr4h (coefficient 0.00004, 95% CI -0.0001 - 0.0002, p = 0.68). Similar results were found when peritoneal glucose exposure was examined as a baseline continuous or categorical variable. A significant 2-way interaction was observed with PD solution type, whereby a progressive increase in D:PCr4h was seen in the patients receiving conventional PD solution, but not in those receiving biocompatible solution. Increases in peritoneal solute transport rate in PD patients over time were not associated with peritoneal glucose exposure, although a strong and positive association with PD solution glucose degradation product content was identified. Peritoneal glucose exposure may be a less important consideration than peritoneal glucose degradation product exposure with respect to peritoneal membrane function over time.

Is the peritoneal dialysis biocompatibility hypothesis dead?

The peritoneal dialysis (PD) biocompatibility hypothesis is that conventional PD solutions with high levels of glucose degradation products (GDPs), glucose and lactate, and low pH cause morphological and functional damage to the peritoneal membrane and that this damage may be attenuated by biocompatible solutions. Functional findings from randomized trials have not supported this hypothesis, and now new data from a large European pediatric peritoneal biopsy study provide a morphologic correlate for this. The implications are discussed.

COMPLEX TECHNOLOGICAL AND BIOLOGICAL RESEARCH OF SOLUTIONS FOR PERITONEAL DIALYSIS

Objective: The purpose of our work was to conduct technological, analytical, and biological investigations and stability studies of peritoneal dialysis (PD) solutions containing glucose and sodium lactate in single-chamber containers.Methods: Different formulations of PD solutions were prepared and sterilized at a temperature of 121 °C during 15 m. UV-spectrophotometric determination was performed using purified water as a blank. The spectra of the solutions were run in the range of 220 to 400 nm for the identification of an absorption maximum (λmax) and measuring the absorbance at 228-230 nm and λmaxbefore and after heat sterilization. λmax of the most PD solutions after sterilization was found in the range of 273 to 281 nm. The potentiometric determination was done for pH measuring PD solutions before and after sterilization. Alternative analytical procedure of direct argent metric method was employed for fast measuring content of chloride ions. Viability of Vero cells was evaluated using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) test, neutral red (NR) uptake assay, and sulforhodamine B (SRB) test.Results: The results showed that the absorbance of the most laboratory batches of PD solutions augments significantly with increasing an autoclave heating time to the sterilization temperature and time of its cooling after sterilization. The longer these parameters, the higher is the absorbance at 228-230 and 273-281 nm indicating 3,4-dideoxyglucoson-3-en (3,4-DGE) and 5-hydroxymethylfurfural (5-HMF) contents, respectively. Glucose degradation is practically absent at short terms of heating and cooling an autoclave while sterilized samples are preserved sterile. Stability studies showed a significant decrease in the absorbance at 228-230 nm during storage with the achievement of a nadir and the following weak increase; an elevation or decrease in the absorption maximum; a substantial decline in the pH of the solution after sterilization and an insignificant pH decrease during storage. The viability of kidney cells was the highest in the SRB test and the lowest one was in the MTT test.Conclusion: The influence of sterilization regimes on the quality of conventional PD solutions and their stability during storage were studied. The highest cytotoxicity was detected in the MTT test, and the lowest one was done in the SRB test, indicating the largest vulnerability of mitochondria under the influence of PD solutions compared to the membranes permeability, functioning of kidney cell lysosomes and the ability of cells to synthesize proteins. Our studies could be useful in the context of planning development of PD solutions with the purpose of authorization and domestic manufacture of these solutions in low-and-middle-income countries.

"Biocompatible" Neutral pH Low-GDP Peritoneal Dialysis Solutions: Much Ado About Nothing?

Adverse outcomes in peritoneal dialysis (PD), including PD related infections, the loss of residual kidney function (RKF), and longitudinal, deleterious changes in peritoneal membrane function continue to limit the long-term success of PD therapy. The observation that these deleterious changes occur upon exposure to conventional glucose-based PD solutions fuels the search for a more biocompatible PD solution. The development of a novel PD solution with a neutral pH, and lower in glucose degradation products (GDPs) compared to its conventional predecessors has been labeled a "biocompatible" solution. While considerable evidence in support of these novel solutions' biocompatibility has emerged from cell culture and animal studies, the clinical benefits as compared to conventional PD solutions are less clear. Neutral pH low GDP (NpHLGDP) PD solutions appear to be effective in reducing infusion pain, but their effects on other clinical endpoints including peritoneal membrane function, preservation of RKF, PD-related infections, and technique and patient survival are less clear. The literature is limited by studies characterized by relatively few patients, short follow-up time, heterogeneity with regards to the novel PD solution type under study, and the different patient populations under study. Nonetheless, the search for a more biocompatible PD solution continues with emerging data on promising non glucose-based solutions.

Hyperbranched polyglycerol is superior to glucose for long-term preservation of peritoneal membrane in a rat model of chronic peritoneal dialysis.

BackgroundReplacing glucose with a better biocompatible osmotic agent in peritoneal dialysis (PD) solutions is needed in PD clinic. We previously demonstrated the potential of hyperbranched polyglycerol (HPG) as a replacement for glucose. This study further investigated the long-term effects of chronic exposure to HPG as compared to a glucose-based conventional PD solution on peritoneal membrane (PM) structure and function in rats.MethodsAdult male Wistar rats received once-daily intraperitoneal injection of 10 mL of HPG solution (1 kDa, HPG 6%) compared to Physioneal™ 40 (PYS, glucose 2.27%) or electrolyte solution (Control) for 3 months. The overall health conditions were determined by blood chemistry analysis. The PM function was determined by ultrafiltration, and its injury by histological and transcriptome-based pathway analyses.ResultsHere, we showed that there was no difference in the blood chemistry between rats receiving the HPG and the Control, while PYS increased serum alkaline phosphatase, globulin and creatinine and decreased serum albumin. Unlike PYS, HPG did not significantly attenuate PM function, which was associated with smaller change in both the structure and the angiogenesis of the PM and less cells expressing vascular endothelial growth factor, α-smooth muscle actin and MAC387 (macrophage marker). The pathway analysis revealed that there were more inflammatory signaling pathways functioning in the PM of PYS group than those of HPG or Control, which included the signaling for cytokine production in both macrophages and T cells, interleukin (IL)-6, IL-10, Toll-like receptors, triggering receptor expressed on myeloid cells 1 and high mobility group box 1.ConclusionsThe results from this experimental study indicate the superiority of HPG to glucose in the preservation of the peritoneum function and structure during the long-term PD treatment, suggesting the potential of HPG as a novel osmotic agent for PD.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-016-1098-z) contains supplementary material, which is available to authorized users.

Supplementation with high-dose trans-resveratrol improves ultrafiltration in peritoneal dialysis patients: a prospective, randomized, double-blind study

Background Ultrafiltration (UF) failure mostly contributes to technical failure in peritoneal dialysis (PD) patients, and one of its responsible factors is peritoneal angiogenesis. Resveratrol has been proposed to have an angiogenesis-ameliorating effect on tumor patients. We hypothesize trans-resveratrol has beneficial effects on angiogenesis-related markers in PD patients. Methods In this prospective, randomized, and double-blind trial, 72 patients were randomly assigned to 12-week treatment of low-dose or high-dose (150 or 450 mg/d) trans-resveratrol or a placebo. Visits were scheduled at 0, 4, 8, and 12 weeks after treatment. Clinical indices including 24-hour UF volume, UF rate, 24-hour urine volume, residual renal function, and dialysis adequacy (kt/v) were measured. Angiogenesis markers including vascular endothelial growth factor (VEGF), fetal liver kinase-1 (Flk-1), angiopoietin-2 (Ang-2), tyrosine kinase 2 (Tie-2), and thrombospondin-1 (Tsp-1) in peritoneal effluent were also assessed by enzyme-linked immunosorbent assay. Results Finally, 64 out of 72 patients were analyzed, 18 in the high-dose group, 22 in the low-dose group, and 24 in the placebo group. Over the 12-week period, patients in the high-dose group [mean change from baseline (95% CI): 171.4 (141.3-201.5) (mL), p = 0.003 (Net UF); 11.3(10.5-12.1) (mL/h), p = 0.02 (UF rate)] or the low-dose group [mean change from baseline (95% CI: 98.1 (49.5-146.7) (mL), p = 0.007 (Net UF); 6.5 (4.4-8.6) (mL/h), p = 0.04 (UF rate)] versus the placebo group had a significantly greater improvement in mean net UF volume and UF rate. The appearance rates of VEGF, Flk-1, and Ang-2 were more significantly reduced (appearance rates of Tie-2 and Tsp-1 increased) in the high-dose group versus the placebo group, but not in the low-dose group. Conclusion Supplementation with trans-resveratrol is beneficial to improve ultrafiltration in PD patients, and high-dose supplementation may improve ultrafiltration by ameliorating angiogenesis induced by conventional lactate-buffered PD solutions.

Update on Peritoneal Dialysis: Core Curriculum 2016

Update on Peritoneal Dialysis: Core Curriculum 2016

Effect of Neutral-pH, Low-Glucose Degradation Product Peritoneal Dialysis Solutions on Residual Renal Function, Urine Volume, and Ultrafiltration: A Systematic Review and Meta-Analysis.

Neutral-pH, low-glucose degradation products solutions were developed in an attempt to lessen the adverse effects of conventional peritoneal dialysis solutions. A systematic review was performed evaluating the effect of these solutions on residual renal function, urine volume, peritoneal ultrafiltration, and peritoneal small-solute transport (dialysate to plasma creatinine ratio) over time. Multiple electronic databases were searched from January of 1995 to January of 2013. Randomized trials reporting on any of four prespecified outcomes were selected by consensus among multiple reviewers. Eleven trials of 643 patients were included. Trials were generally of poor quality. The meta-analysis was performed using a random effects model. The use of neutral-pH, low-glucose degradation products solutions resulted in better preserved residual renal function at various study durations, including >1 year (combined analysis: 11 studies; 643 patients; standardized mean difference =0.17 ml/min; 95% confidence interval, 0.01 to 0.32), and greater urine volumes (eight studies; 598 patients; mean difference =128 ml/d; 95% confidence interval, 58 to 198). There was no significant difference in peritoneal ultrafiltration (seven studies; 571 patients; mean difference =-110; 95% confidence interval, -312 to 91) or dialysate to plasma creatinine ratio (six studies; 432 patients; mean difference =0.03; 95% confidence interval, 0.00 to 0.06). The use of neutral-pH, low-glucose degradation products solutions results in better preservation of residual renal function and greater urine volumes. The effect on residual renal function occurred early and persisted beyond 12 months. Additional studies are required to evaluate the use of neutral-pH, low-glucose degradation products solutions on hard clinical outcomes.

Effect of Neutral pH and Low-Glucose Degradation Product-Containing Peritoneal Dialysis Solution on Residual Renal Function in Peritoneal Dialysis Patients: A Meta-Analysis

Background: Glucose degradation products (GDPs) in peritoneal dialysis (PD) solution (PDS) have been shown to inflict damage to the kidney, which is the major organ for advanced glycosylation end product elimination. Hence, this study investigated whether new PDSs with neutral pH and low-GDPs have a beneficial effect on the preservation of residual renal function (RRF) among PD patients. Methods: Randomized controlled trials examining the effect of neutral pH and low-GDP PDSs on RRF in PD patients >18 years old compared with conventional PDSs were selected. The modality of PD treatment was continuous ambulatory PD. The primary outcome variable was mean RRF value. Weekly Kt/V, urine volume, peritoneal ultrafiltration, blood pressure and all-cause mortality of PD patients were measured as secondary outcome variables. Results: We identified 6 randomized controlled trials and found that patients using low-GDP PDSs had a much slower rate of RRF loss compared with patients using conventional PDSs [mean difference (MD) = 0.45, 95% confidence intervals (CI) 0.10-0.80, p = 0.01]. In addition, weekly Kt/V was markedly improved in the low-GDP PDS group (MD = 0.13, 95% CI 0.06-0.21, p = 0.0005), and urine volume was increased (MD = 110.34, 95% CI 8.58-212.10, p = 0.03). No significant differences were observed between the two groups with respect to peritoneal ultrafiltration, blood pressure and risk of all-cause mortality. Conclusion: Our meta-analysis demonstrates a significant benefit of using low-GDP PDSs for RRF preservation in PD patients. Further trials are needed to determine whether this beneficial effect can affect long-term clinical outcomes.

Utility of Urinary Biomarkers in Predicting Loss of Residual Renal Function: The BAL Anz Trial

The ability of urinary biomarkers to predict residual renal function (RRF) decline in peritoneal dialysis (PD) patients has not been defined. The present study aimed to explore the utility of established biomarkers from kidney injury models for predicting loss of RRF in incident PD patients, and to evaluate the impact on RRF of using neutral-pH PD solution low in glucose degradation products. The study included 50 randomly selected participants from the balANZ trial who had completed 24 months of follow-up. A change in glomerular filtration rate (GFR) was used as the primary clinical outcome measure. In a mixed-effects general linear model, baseline measurements of 18 novel urinary biomarkers and albumin were used to predict GFR change. The model was further used to evaluate the impact of biocompatible PD solution on RRF, adjusted for each biomarker. Baseline albuminuria was not a useful predictor of change in RRF in PD patients (p = 0.84). Only clusterin was a significant predictor of GFR decline in the whole population (p = 0.04, adjusted for baseline GFR and albuminuria). However, the relationship was no longer apparent when albuminuria was removed from the model (p = 0.31). When the effect of the administered PD solutions was examined using a model adjusted for PD solution type, baseline albuminuria, and GFR, higher baseline urinary concentrations of trefoil factor 3 (TFF3, p = 0.02), kidney injury molecule 1 (KIM-1, p = 0.04), and interferon γ-induced protein 10 (IP-10, p = 0.03) were associated with more rapid decline of RRF in patients receiving conventional PD solution compared with biocompatible PD solution. Higher urinary levels of kidney injury biomarkers (TFF3, KIM-1, IP-10) at baseline predicted significantly slower RRF decline in patients receiving biocompatible PD solutions. Findings from the present investigation should help to guide future studies to validate the utility of urinary biomarkers as tools to predict RRF decline in PD patients.

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.