Higher peritoneal transport status is associated with higher mortality and technique failure in the Australian and New Zealand peritoneal dialysis patient populations

Inflammation and all-cause mortality in patients undergoing peritoneal dialysis

OBJECTIVE

This study aimed to evaluate inflammatory biomarkers in patients undergoing peritoneal dialysis and investigate their association with all-cause mortality or transfer to hemodialysis.

METHODS

This prospective cohort study included 43 patients undergoing peritoneal dialysis. Plasma levels of cytokines were measured using flow cytometry and capture enzyme-linked immunosorbent assay. Biomarkers were categorized based on their respective median values. Survival analysis was conducted using the Kaplan-Meier estimator, considering two outcomes: all-cause mortality and transfer to hemodialysis.

RESULTS

After adjusting for confounding factors, plasma levels above the median of the levels of CCL2 and plasma, as well as below the median of TNF-α, and the median of dialysate IL-17 levels, were associated with an increased risk of experiencing the specified outcomes after approximately 16 months of follow-up.

CONCLUSION

These findings suggest that inflammatory biomarkers may be a valuable tool for predicting all-cause mortality and transfer to hemodialysis in patients undergoing peritoneal dialysis.

The relationship between changes in peritoneal membrane solute transfer characteristics and cardiac remodeling in patients with peritoneal dialysis

INTRODUCTION

We aimed to determine the relationship between the dilatation of the heart chambers and the change in peritoneal membrane solute transfer characteristics (PMTC) in long-term peritoneal dialysis (PD) patients.

METHODS

This is a retrospective, single-center study including the follow-up of maintenance PD patients. According to the changes in PMTC from baseline to the last visit, patients were divided into three groups; stable (n = 11), increased (n = 41), and decreased transporters (n = 35).

RESULTS

Left atrium (LA) and Right ventricle (RV) dilatation were more prominent in the PMTC-decreased group compared to PMTC-increased and stable groups (p < 0.001 and p = 0.07, respectively). The Cox regression analysis showed that only decreased PMTC was associated with LA dilatation (HR 2.89 [CI 95%1.54, 5.45] p < 0.01) and RV dilatation (HR 3.01 [CI 95%1.40, 6.21] p < 0.01).

CONCLUSION

PD can be associated with unfavorable dynamic changes in cardiac structure and functions even at the subclinical level.

Survival and its relationship with the type of peritoneal solute transfer rate, in patients with chronic kidney disease incident on peritoneal dialysis therapy in RTS Colombia between the years 2007-2017

INTRODUCTION

In some studies, the peritoneal solute transfer rate (PSTR) through the peritoneal membrane has been related to an increased risk of mortality. It has been observed in the literature that those patients with rapid diffusion of solutes through the peritoneal membrane (high/fast transfer) and probably those with high average transfer characterized by the Peritoneal Equilibrium Test (PET) are associated with higher mortality compared to those patients who have a slow transfer rate. However, some authors have not documented this fact. In the present study, we want to evaluate the (etiological) relationship between the characteristics of peritoneal membrane transfer and mortality and survival of the technique in an incident population on peritoneal dialysis in RTS Colombia during the years 2007-2017 using a competing risk model.

MATERIALS AND METHODS

A retrospective cohort study was carried out at RTS Colombia in the period between 2007 and 2017. In total, there were 8170 incident patients older than 18 years, who had a Peritoneal Equilibration Test (PET) between 28 and 180 days from the start of therapy. Demographic, clinical, and laboratory variables were evaluated. The (etiological) relationship between the type of peritoneal solute transfer rate at the start of therapy and overall mortality and technique survival were analyzed using a competing risk model (cause-specific proportional hazard model described by Royston-Lambert).

RESULTS

Patients were classified into four categories based on the PET result: Slow/Low transfer (16.0%), low average (35.4%), high average (32.9%), and High/Fast transfer (15.7%). During follow-up, with a median of 730 days, 3025 (37.02%) patients died, 1079 (13.2%) were transferred to hemodialysis and 661 (8.1%) were transplanted. In the analysis of competing risks, adjusted for age, sex, presence of DM, HTA, body mass index, residual function, albumin, hemoglobin, phosphorus, and modality of PD at the start of therapy, we found cause-specific HR (HRce) for high/fast transfer was 1.13 (95% CI 0.98-1.30) p = 0.078, high average 1.08 (95% CI 0.96-1.22) p = 0.195, low average 1.09 (95% CI 0.96-1.22) p = 0.156 compared to the low/slow transfer rate. For technique survival, cause-specific HR for high/rapid transfer of 1.22 (95% CI 0.98-1.52) p = 0.66, high average HR was 1.10 (95% CI 0.91-1.33) p = 0.296, low average HR of 1.03 (95% CI 0.85-1.24) p = 0.733 compared with the low/slow transfer rate, adjusted for age, sex, DM, HTA, BMI, residual renal function, albumin, phosphorus, hemoglobin, and PD modality at start of therapy. Non-significant differences.

CONCLUSIONS

When evaluating the etiological relationship between the type of peritoneal solute transfer rate and overall mortality and survival of the technique using a competing risk model, we found no etiological relationship between the characteristics of peritoneal membrane transfer according to the classification given by Twardowski assessed at the start of peritoneal dialysis therapy and overall mortality or technique survival in adjusted models. The analysis will then be made from the prognostic model with the purpose of predicting the risk of mortality and survival of the technique using the risk subdistribution model (Fine & Gray).

Exploring the Role of Cell-Free Nucleic Acids and Peritoneal Dialysis: A Narrative Review

INTRODUCTION

Cell-free nucleic acids (cf-NAs) represent a promising biomarker of various pathological and physiological conditions. Since its discovery in 1948, cf-NAs gained prognostic value in oncology, immunology, and other relevant fields. In peritoneal dialysis (PD), blood purification is performed by exposing the peritoneal membrane. Relevant sections: Complications of PD such as acute peritonitis and peritoneal membrane aging are often critical in PD patient management. In this review, we focused on bacterial DNA, cell-free DNA, mitochondrial DNA (mtDNA), microRNA (miRNA), and their potential uses as biomarkers for monitoring PD and its complications. For instance, the isolation of bacterial DNA in early acute peritonitis allows bacterial identification and subsequent therapy implementation. Cell-free DNA in peritoneal dialysis effluent (PDE) represents a marker of stress of the peritoneal membrane in both acute and chronic PD complications. Moreover, miRNA are promising hallmarks of peritoneal membrane remodeling and aging, even before its manifestation. In this scenario, with multiple cytokines involved, mtDNA could be considered equally meaningful to determine tissue inflammation.

CONCLUSIONS

This review explores the relevance of cf-NAs in PD, demonstrating its promising role for both diagnosis and treatment. Further studies are necessary to implement the use of cf-NAs in PD clinical practice.

Differential expression and clinical significance of IGF2BP3 in peritoneal dialysate of patients with varying duration of peritoneal dialysis

This study aims to investigate the differential expression of insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) in the peritoneal dialysate among patients with different durations of peritoneal dialysis and its association with the angiogenic marker vascular* endothelial growth factor (VEGF), the fibronectin (FN), and various clinical indicators. A cohort of 122 peritoneal dialysis patients was categorized into short-term (≤1 year, n = 33), mid-term (>1 and ≤5 years, n = 55), and long-term (>5 years, n = 34) groups based on dialysis duration. We utilized enzyme-linked immunosorbent assay (ELISA) and western blot assays to quantify the levels of IGF2BP3, VEGF, and FN in the dialysate. Our findings showed a progressive increase in IGF2BP3 levels with the duration of PD, with the long-term group exhibiting significantly higher levels than both the short-term and mid-term groups (p < 0.001). A positive correlation between IGF2BP3 and VEGF (r = 0.386, p = 0.013), as well as between IGF2BP3 and FN (r = 0.340, p = 0.030), was observed. IGF2BP3 levels also correlated positively with serum creatinine, calcium, and phosphorus levels. In vitro analysis further confirmed that IGF2BP3 expression is enhanced in human peritoneal mesothelial cells under high-glucose conditions (p < 0.05). The study highlights the potential of IGF2BP3 in PD effluent as a biomarker for monitoring PF progression, with its expression significantly correlated with the duration of PD (Pearson r = 0.897, p < 0.001). In conclusion, our results underscore a correlation between elevated IGF2BP3 levels and PD duration, suggesting the clinical significance of IGF2BP3 as a biomarker for PF progression.

Role of endothelial hyaluronan in peritoneal membrane transport and disease conditions during peritoneal dialysis

Peritoneal membrane dysfunction in peritoneal dialysis (PD) is primarily attributed to angiogenesis; however, the integrity of vascular endothelial cells can affect peritoneal permeability. Hyaluronan, a component of the endothelial glycocalyx, is reportedly involved in preventing proteinuria in the normal glomerulus. One hypothesis suggests that development of encapsulating peritoneal sclerosis (EPS) is triggered by protein leakage due to vascular endothelial injury. We therefore investigated the effect of hyaluronan in the glycocalyx on peritoneal permeability and disease conditions. After hyaluronidase-mediated degradation of hyaluronan on the endothelial cells of mice, macromolecules, including albumin and β2 microglobulin, leaked into the dialysate. However, peritoneal transport of small solute molecules was not affected. Pathologically, hyaluronan expression was diminished; however, expression of vascular endothelial cadherin and heparan sulfate, a core protein of the glycocalyx, was preserved. Hyaluronan expression on endothelial cells was studied using 254 human peritoneal membrane samples. Hyaluronan expression decreased in patients undergoing long-term PD treatment and EPS patients treated with conventional solutions. Furthermore, the extent of hyaluronan loss correlated with the severity of vasculopathy. Hyaluronan on endothelial cells is involved in the peritoneal transport of macromolecules. Treatment strategies that preserve hyaluronan in the glycocalyx could prevent the leakage of macromolecules and subsequent related complications.

The Peritoneal Membrane and Its Role in Peritoneal Dialysis

A healthy and functional peritoneal membrane is key to achieving sufficient ultrafiltration and restoring fluid balance, a major component of high-quality prescription in patients treated with peritoneal dialysis (PD). Variability in membrane function at the start of PD or changes over time on treatment influence dialysis prescription and outcomes, and dysfunction of the peritoneal membrane contributes to fluid overload and associated complications. In this review, we summarize the current knowledge about the structure, function, and pathophysiology of the peritoneal membrane with a focus on clinical implications for patient-centered care. We also discuss the molecular and genetic mechanisms of solute and water transport across the peritoneal membrane, including the role of aquaporin water channels in crystalloid versus colloid osmosis; why and how to assess membrane function using peritoneal equilibration tests; the etiologies of membrane dysfunction and their specific management; and the effect of genetic variation on membrane function and outcomes in patients treated with PD. This review also identifies the gaps in current knowledge and perspectives for future research to improve our understanding of the peritoneal membrane and, ultimately, the care of patients treated with PD.

Identification of Genes Associated with Decreasing Abundance of Monocytes in Long-Term Peritoneal Dialysis Patients

Purpose

Chronic kidney disease (CKD) will become an end-stage renal disease (ESRD) at stage 5. Peritoneal dialysis (PD) is required for renal replacement therapy. This study aims to identify monocytes-related genes in peritoneal cells from long-term PD (LPD) patients and short-term PD (SPD) patients.

Methods

Bulk RNA-seq data (GSE125498 dataset) and ScRNA-seq data (GSE130888) were downloaded to identify differentially expressed genes, monocytes-related genes, and monocytes marker genes in LPD patients. Immune infiltration was analyzed in the GSE125498 dataset. Core genes associated with monocytes changes were screened out, followed by functional analysis and expression validation using RT-PCR.

Results

Monocytes are the most abundant immune cell in PD. The number of monocytes was remarkably decreased in LPD compared with SPD. A total of 16 up-regulated core genes negatively correlated with the abundance of monocytes were obtained in LPD. The expression of 16 core genes was lower in monocyte clusters than that in other cell clusters. In addition, LCK, CD3G, CD3E, CD3D, and LAT were involved in the signaling pathways of Th1 and Th2 cell differentiation, T cell receptor signaling pathway, and Th17 cell differentiation. CD2 was involved in hematopoietic cell lineage signaling pathway.

Conclusion

Identification of monocytes related-genes and related signaling pathways could be helpful in understanding the molecular mechanism of monocytes changes during PD.

The centre-calculated cutoff value is better for identifying fast peritoneal solute transfer of patients on peritoneal dialysis than the traditional value: a retrospective cohort study

Background

The mean 4-h dialysate to plasma ratio of creatinine (4-h D/Pcr) is a vital cutoff value for recognizing the fast peritoneal solute transfer rate (PSTR) in patients on peritoneal dialysis (PD); however, it shows a noticeable centre effect. We aimed to investigate our centre-calculated cutoff value (CCV) of 4-h D/Pcr and compare it with the traditional cutoff value (TCV) (0.65).

Methods

In this study, we enrolled incident PD patients at our centre from 2008 to 2019, and divided them into fast or non-fast PSTR groups according to baseline 4-h D/Pcr-based CCV or TCV. We compared the efficiency of the fast PSTR recognized by two cutoff values in predicting mortality, ultrafiltration (UF) insufficiency and technical survival.

Results

In total, 1905 patients were enrolled, with a mean 4-h D/Pcr of 0.71 ± 0.11. Compared with TCV (0.65), CCV (0.71) showed superiority in predicting mortality of PD patients [hazard ratio (HR) 1.27, 95% confidence interval (CI) 1.02-1.59 vs HR 1.24, 95% CI 0.97-1.59]. The odds ratio (OR) of the fast PSTR in centre classification was slightly higher than traditional classification in predicting UF insufficiency (OR 1.67, 95% CI 1.25-2.24 vs OR 1.60, 95% CI 1.15-2.22). Additionally, the restricted cubic splines 4-h D/Pcr has an S-shaped association with mortality and UF insufficiency, and the inflection points of 4-h D/Pcr were 0.71 (equal to CCV).

Conclusions

The CCV of 4-h D/Pcr for identifying fast PSTR was 0.71. It was superior to TCV in predicting mortality and UF insufficiency.

Changes in erythropoiesis-stimulating agent responsiveness after transfer to combined therapy with peritoneal dialysis and hemodialysis for patients on peritoneal dialysis: A prospective multicenter study in Japan

INTRODUCTION

Inadequate dialysis and fluid overload are corrected after starting combined therapy with peritoneal dialysis (PD) and hemodialysis (HD). However, the effects on anemia management has not been elucidated.

METHODS

We conducted a prospective, multicenter, observational cohort study of 40 PD patients (age, 60 ± 10 years; male, 88%; median PD duration, 28 months) starting combined therapy and investigated changes in several clinical parameters, including erythropoiesis-stimulating agent (ESA) resistance index (ERI).

RESULTS

ERI decreased significantly during 6 months after switching to combined therapy (from 11.8 [IQR 8.0-20.4] units/week/kg/(g/dL) to 7.8 [IQR 3.9-18.6] units/week/kg/(g/dL), p = 0.047). Body weight, urinary volume, serum creatinine and the dialysate-to-plasma creatinine ratio (D/P Cr) decreased, whereas hemoglobin and serum albumin increased. In subgroup analysis, the changes in ERI were not affected by cause for starting combined therapy, PD holiday and D/P Cr.

CONCLUSION

Although detailed mechanism was unclear, ESA responsiveness improved after switching from PD alone to combined therapy.

Metabolomic profiling of overnight peritoneal dialysis effluents predicts the peritoneal equilibration test type

This study primarily aimed to evaluate whether peritoneal equilibration test (PET) results can be predicted through the metabolomic analysis of overnight peritoneal dialysis (PD) effluents. From a total of 125 patients, overnight PD effluents on the day of the first PET after PD initiation were analyzed. A modified 4.25% dextrose PET was performed, and the PET type was categorized according to the dialysate-to-plasma creatinine ratio at the 4-h dwell time during the PET as follows: high, high average, low average, or low transporter. Nuclear magnetic resonance (NMR)-based metabolomics was used to analyze the effluents and identify the metabolites. The predictive performances derived from the orthogonal projection to latent structure discriminant analysis (OPLS-DA) modeling of the NMR spectrum were estimated by calculating the area under the curve (AUC) using receiver operating characteristic curve analysis. The OPLS-DA score plot indicated significant metabolite differences between high and low PET types. The relative concentrations of alanine and creatinine were greater in the high transporter type than in the low transporter type. The relative concentrations of glucose and lactate were greater in the low transporter type than in the high transporter type. The AUC of a composite of four metabolites was 0.975 in distinguish between high and low PET types. Measured PET results correlated well with the total NMR metabolic profile of overnight PD effluents.

A retrospective study of baseline peritoneal transport character and left ventricular hypertrophy in incident peritoneal dialysis patients: interrelationship and prognostic impacts

BACKGROUND

Left ventricular hypertrophy is associated with adverse outcomes among peritoneal dialysis patients. The aim of this study was to evaluate the prognostic impact of baseline left ventricular hypertrophy and its relationship with baseline peritoneal transfer characteristics in peritoneal dialysis patients.

METHODS

We enrolled 151 incident peritoneal dialysis patients to perform a multicentric retrospective cohort study since January 1, 2017 to January 31, 2021. Patients were grouped based on baseline dialysate-to-plasma creatinine ratio at 4 h as follows: low (<0.50), low average (0.5-0.64), high average (0.65-0.80) and high (≥0.81). Echocardiography and clinic data were recorded yearly. The Cox proportional hazards models and competing risk model were used to evaluate patients' survival. Generalized linear mixed models were performed to explore risk factors associated with left ventricular hypertrophy.

RESULTS

During a median follow-up period of 33 months (range, 16-48 months), 21 (13.9%) patients died, including 16 (10.60%) cardiovascular deaths. Controlling the competing risks of switching to hemodialysis, kidney transplantation and loss to follow-up, baseline left ventricular hypertrophy was an independent risk factor for all-cause mortality (subdistribution hazard ratio, 2.645; 95% confidence interval, 1.156-6.056; p = 0.021). Baseline high and high average transport status were positively related to left ventricular mass index and left atrium diameter 2 years after PD initiation.

CONCLUSION

Baseline fast peritoneal solute transport rate may be an effect factor for aggravating left ventricular hypertrophy which predicted poor outcomes for peritoneal dialysis patients. The findings offered important ideas for further prospective intervention study.

Gene polymorphisms of VEGF and KDR are associated with initial fast peritoneal solute transfer rate in peritoneal dialysis

Background

Peritoneal dialysis (PD) is an effective and successful renal replacement therapy. The baseline peritoneal solute transfer rate (PSTR) is related to local membrane inflammation and may be partially genetically determined. Herein, we focused on vascular endothelial growth factor (VEGF) and its receptor, kinase insert domain containing receptor (KDR).

Methods

This study recruited 200 PD patients from Renji Hospital in Shanghai, China. We analysed the association between the polymorphisms of VEGF and KDR and the 4-hour dialysate-to-plasma ratio for creatinine (4 h D/P Cr), which was measured between one and three months after initiating PD.

Results

The CC genotype in VEGF rs3025039 and the AA genotype in KDR rs2071559 were both positively associated with a fast baseline PSTR (VEGF rs3025039 CC vs. TT + TC: 0.65 ± 0.12 vs. 0.61 ± 0.11; P = 0.029; KDR rs2071559 AA vs. GA + GG: 0.65 ± 0.12 vs. 0.62 ± 0.12; P = 0.039).

Conclusion

Baseline PSTR was partly determined by VEGF and KDR gene polymorphisms.

Glycoprotein 96 in Peritoneal Dialysis Effluent-Derived Extracellular Vesicles: A Tool for Evaluating Peritoneal Transport Properties and Inflammatory Status

Background

Extracellular vesicles (EVs) from peritoneal dialysis effluent (PDE), containing molecules such as proteins and microRNAs (miRNAs), may be potential biological markers to monitor peritoneal function or injury. Peritoneal inflammation is an important determinant of peritoneal solute transport rate (PSTR). Thus, the aim of this study is to determine whether the specific proteins capable of evaluating the PSTR could be found in PDE-EVs, and explore the underlying mechanism for the association between PSTR and peritoneal inflammation.

Methods

Sixty patients undergoing peritoneal dialysis (PD) were divided into two groups: high/high average transport (H/A) group (PET >0.65) and low/low average transport (L/A) group (PET <0.65). EVs derived from PDE (PDE-EVs) were isolated by ultracentrifugation. Proteomic analysis was performed to explore the differentially expressed proteins and identify the potential biomarkers in PDE-EVs from the two groups, and we focused on glycoprotein 96 (GP96) as it could be involved in the inflammatory process. The expression of GP96 in PDE-EVs and inflammatory cytokines was quantified by real-time PCR and enzyme-linked immunosorbent assay. The infiltration of macrophages and neutrophils into the peritoneum was detected using immunohistochemistry in a PD rat model.

Results

The expression of PDE-EVs-GP96 was significantly higher in the H/A group, and was positively correlated with the PSTR and the level of the inflammatory factor interleukin (IL)-6. GP96-enriched EVs enhanced the secretion of proinflammatory cytokines IL-1β, IL-6, tumor necrosis factor (TNF)-α, and IL-8 in macrophages, which was reversed by a pharmacological GP96-specific inhibitor (PU-WS13). The GP96 inhibitor also reduced local peritoneal inflammation by decreasing the infiltration of inflammatory cells and levels of proinflammatory cytokines (IL-6 and TNF-α) and chemokines (CCL2, CXCL1, and CXCL2) in a PD rat model.

Conclusions

PDE-EVs-GP96 is a new promising tool to evaluate the status of peritoneal inflammation and PSTR, and the mechanism may be related to affecting the inflammatory properties of macrophages.

Increased risk of modality failure with higher serum uric acid level in continuous ambulatory peritoneal dialysis patients: a prospective cohort study

BACKGROUND

Peritoneal dialysis (PD) is one of the most important kidney replacement therapies for patients with end-stage kidney disease (ESKD). PD technique failure can lead to an escalated cost and increased infectious and cardiovascular risk, up and including to death. The accumulation of uric acid (UA) was associated with adverse outcomes in ESKD patients. However, the relationship between serum UA and technique failure is little explored.

METHODS

Here, a total of 266 continuous ambulatory peritoneal dialysis (CAPD) patients (age, 41.8 ± 12.6 years; 125 males) were enrolled and followed up for 31.7 months. Serum UA levels were examined at baseline and each visit. Subjects were divided into three groups according to their baseline serum UA concentrations. Multivariable Cox regression models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of PD technique failure.

RESULTS

The level of serum UA increased gradually as time prolonged. During the follow-up period, 77 (28.9%) patients occurred PD technique failure, of which 56 (21.1%) transferred to hemodialysis (HD) and 21 (7.9%) died. Compared to the lowest UA tertile, after adjusting for potential confounders, HRs of technique failure in tertile 2 and tertile 3 were 1.82 (95% CI: 0.95-3.49) and 2.03 (95% CI: 1.05-3.92), respectively, and p for trend was 0.043. Adjusted HRs of all-cause technique failure, transferring to HD and mortality with each 1 mg/dL increase in serum UA were 1.20 (95% CI: 1.03-1.40, p = 0.019), 1.22 (95% CI: 1.01-1.48, p = 0.039), and 1.25 (95% CI: 0.94-1.67, p = 0.128), respectively.

CONCLUSION

Higher serum UA level predicted higher risk of technique failure in CAPD patients.

Peritoneal transport status and first episode of peritonitis: a large cohort study

BACKGROUND

Peritonitis is one of the most serious complications of peritoneal dialysis (PD). This study aimed to explore the relationship between peritoneal transport status and the first episode of peritonitis, as well as the prognosis of patients undergoing continuous ambulatory peritoneal dialysis (CAPD).

METHOD

A retrospective cohort study was conducted, analyzing data of CAPD patients from 1st January 2009, to 31st December 2017. Baseline data within 3 months after PD catheter placement was recorded. Cox multivariate regression analysis was performed to determine the risk factors for the first episode of peritonitis, technique failure and overall mortality.

RESULTS

A total of 591 patients were included in our analysis, with a mean follow-up visit of 49 months (range: 27-75months). There were 174 (29.4%) patients who had experienced at least one episode of peritonitis. Multivariate Cox regression analysis revealed that a higher peritoneal transport status (high and high-average) (HR 1.872, 95%CI 1.349-2.599, p = 0.006) and hypoalbuminemia (HR 0.932,95% CI 0.896, 0.969, p = 0.004) were independent risk factors for the occurrence of the first episode of peritonitis. In addition, factors including gender (male) (HR 1.409, 95%CI 1.103, 1.800, p = 0.010), low serum albumin (HR 0.965, 95%CI 0.938, 0.993, p = 0.015) and the place of residence (rural) (HR 1.324, 95%CI 1.037, 1.691, p = 0.024) were independent predictors of technique failure. Furthermore, low serum albumin levels (HR 0.938, 95%CI 0.895, 0.984, p = 0.008) and age (>65years) (HR 1.059, 95%CI 1.042, 1.076, p < 0.001) were significantly associated with the risk of overall mortality of PD patients.

CONCLUSIONS

Baseline hypoalbuminemia and a higher peritoneal transport status are risk factors for the first episode of peritonitis. Factors including male gender, hypoalbuminemia, and residing in rural areas are associated with technique failure, while hypoalbuminemia and age (>65years) are predictors of the overall mortality in PD patients. Nevertheless, the peritoneal transport status does not predict technique failure or overall mortality of PD patients.

A genome-wide association study suggests correlations of common genetic variants with peritoneal solute transfer rates in patients with kidney failure receiving peritoneal dialysis

Movement of solutes across the peritoneum allows for the use of peritoneal dialysis to treat kidney failure. However, there is a large inter-individual variability in the peritoneal solute transfer rate (PSTR). Here, we tested the hypothesis that common genetic variants are associated with variability in PSTR. Of the 3561 participants from 69 centers in six countries, 2850 with complete data were included in a genome-wide association study. PSTR was defined as the four-hour dialysate/plasma creatinine ratio from the first peritoneal equilibration test after starting PD. Heritability of PSTR was estimated using genomic-restricted maximum-likelihood analysis, and the association of PSTR with a genome-wide polygenic risk score was also tested. The mean four-hour dialysate/plasma creatinine ratio in participants was 0.70. In 2212 participants of European ancestry, no signal reached genome-wide significance but 23 single nucleotide variants at four loci demonstrated suggestive associations with PSTR. Meta-analysis of ancestry-stratified regressions in 2850 participants revealed five single-nucleotide variants at four loci with suggestive correlations with PSTR. Association across ancestry strata was consistent for rs28644184 at the KDM2B locus. The estimated heritability of PSTR was 19%, and a permuted model polygenic risk score was significantly associated with PSTR. Thus, this genome-wide association study of patients receiving peritoneal dialysis bolsters evidence for a genetic contribution to inter-individual variability in PSTR.

Traduction des Recommandations de l'ISPD pour l'évaluation du dysfonctionnement de la membrane péritonéale chez l'adulte

Informations concernant cette traductionDans le cadre d’un accord de partenariat entre l’ISPD et le RDPLF, le RDPLF est le traducteur français officiel des recommandations de l’ISPD. La traduction ne donne lieu à aucune compensation financière de la part de chaque société et le RDPLF s’est engagé à traduire fidèlement le texte original sous la responsabilité de deux néphrologues connus pour leur expertise dans le domaine. Avant publication le texte a été soumis à l’accord de l’ISPD. La traduction est disponible sur le site de l’ISPD et dans le Bulletin de la Dialyse à Domicile.Le texte est, comme l’original, libremement téléchargeable sous licence copyright CC By 4.0https://creativecommons.org/licenses/by/4.0/Cette traduction est destinée à aider les professionnels de la communauté francophone à prendre connaissance des recommandations de l’ISPD dans leur langue maternelle. Toute référence dans un article doit se faire au texte original en accès libre :Peritoneal Dialysis International https://doi.org/10.1177/0896860820982218 Dans les articles rédigés pour des revues françaises, conserver la référence à la version originale anglaise ci dessus, mais ajouter «version française  https://doi.org/10.25796/bdd.v4i3.62673"»TraducteursDr Christian Verger, néphrologue, président du RDPLFRDPLF, 30 rue Sere Depoin, 95300 Pontoise – FranceProfesseur Max Dratwa, néphrologueHôpital Universitaire Brugmann – Bruxelles – Belgique

The Effect of Far-Infrared Therapy on the Peritoneal Membrane Transport Characteristics of Uremic Patients Undergoing Peritoneal Dialysis: An Open-Prospective Proof-of-Concept Study

Long-term peritoneal dialysis (PD) can lead to detrimental changes in peritoneal membrane function, which may be related to the accumulation of glucose degradation products. A previous study demonstrated that 6 months of far-infrared (FIR) therapy may decrease glucose degradation products in PD dialysate. Due to limited literature on this matter, this study aims to investigate the effect of FIR therapy on the peritoneal membrane transport characteristics of PD patients. Patients were grouped according to baseline peritoneal transport status: lower transporters (low and low-average) and higher transporters (high-average and high). Both groups underwent 40 min of FIR therapy twice daily for 1 year. In lower transporters, FIR therapy increased weekly dialysate creatinine clearance (6.91 L/wk/1.73 m²; p = 0.04) and D/P creatinine (0.05; p = 0.01). In higher transporters, FIR therapy decreased D/P creatinine (−0.05; p = 0.01) and increased D/D0 glucose (0.05; p = 0.006). Fifty percent of high transporter patients shifted to high-average status after FIR therapy. FIR therapy may decrease D/P creatinine for patients in the higher transporter group and cause high transporters to shift to high-average status, which suggests the potential of FIR therapy in improving peritoneal membrane function in PD patients.

The prognosis and risk factors of baseline high peritoneal transporters on patients with peritoneal dialysis

The relationship between baseline high peritoneal solute transport rate (PSTR) and the prognosis of peritoneal dialysis (PD) patients remains unclear. The present study combined clinical data and basic experiments to investigate the impact of baseline PSTR and the underlying molecular mechanisms. A total of 204 incident CAPD patients from four PD centres in Shanghai between 1 January 2014 and 30 September 2020 were grouped based on a peritoneal equilibration test after the first month of dialysis. Analysed with multivariate Cox and logistic regression models, baseline high PSTR was a significant risk factor for technique failure (AHR 5.70; 95% CI 1.581 to 20.548 p = 0.008). Baseline hyperuricemia was an independent predictor of mortality (AHR 1.006 95%CI 1.003 to 1.008, p < 0.001) and baseline high PSTR (AOR 1.007; 95%CI 1.003 to 1.012; p = 0.020). Since uric acid was closely related to high PSTR and adverse prognosis, the in vitro experiments were performed to explore the underlying mechanisms of which uric acid affected peritoneum. We found hyperuricemia induced epithelial‐to‐mesenchymal transition (EMT) of cultured human peritoneal mesothelial cells by activating TGF‐β1/Smad3 signalling pathway and nuclear transcription factors. Conclusively, high baseline PSTR induced by hyperuricaemia through EMT was an important reason of poor outcomes in CAPD patients.

Risk factors for mortality in patients undergoing peritoneal dialysis: a systematic review and meta-analysis

Aim

Inconsistent investigations of the risk factors for all-cause mortality in patients undergoing peritoneal dialysis (PD) were reported. The present meta-analysis aimed to assess the impact of some clinical characteristics on the risk of mortality in PD patients.

Methods

PubMed and Embase were systematically searched for studies evaluating the risk factors for all-cause mortality in PD patients. Hazard ratio (HR) and 95% confidence interval (CI) were derived using a random-effect or fixed-effect model considering the heterogeneity across studies.

Result

A total of 26 studies were included in this meta-analysis in accordance with the inclusion and exclusion criteria. Age, primary cardiovascular diseases, diabetes mellitus, and high level of alkaline phosphatase showed significant positive associations with elevated risk of all-cause and cardiovascular mortality in PD patients, while hemoglobin acted as a benefit factor. Furthermore, early onset of peritonitis, high peritoneal transport status, elevated body mass index and high-sensitivity C-reactive protein could also considerably increase the risk of all-cause mortality. The absolute serum level of magnesium, potassium, and uric acid required to improve survival in PD patients should be verified further.

Conclusions

Multiple factors could affect the risk of mortality in PD patients.

Associations between dialysate interleukin-6 and Tie-2 and peritoneal solute transport rate and outcomes for patients undergoing peritoneal dialysis: A prospective cohort study

Objectives

We designed this prospective observational study to clarify the associations between dialysate IL-6, a marker of ongoing peritoneal inflammation, Tie2, an important factor in angiogenesis in the peritoneum, and a high peritoneal solute transport rate (PSTR) in patients undergoing peritoneal dialysis (PD) and to investigate their outcome predictive roles.

Methods

A total of 60 stable continuous ambulatory peritoneal dialysis (CAPD) patients from a single center in China were analyzed in this prospective study. We measured dialysate levels of IL-6 and Tie-2 using ELISAs. Our primary study endpoint was all-cause mortality with 10 years' follow-up.

Results

For the evaluation of PSTR, we used the Dialysis/Plasma creatinine (D/Pcr) ratio. We subdivided the patients into two groups for statistical evaluation: low and low average D/Pcr (<0.64; L/A), and high and high average D/Pcr (≥0.65; H/A) transporters. The mean levels of dialysates IL-6 (21.71 ± 8.88 pg/mL) and Tie-2 (1.23 ± 0.43 ng/mL) were significantly higher in the H/A (high and high average, group than those in the L/A group (13.94 ± 5.43 pg/mL, p<0.001 and 0.95 ± 0.43 ng/mL, p=0.019; respectively). Moreover, IL-6 and Tie-2 were positively correlated with D/Pcr (r=0.366, p=0.004 and r=0.402, p=0.001; respectively). Both dialysates IL-6 and Tie-2 were independent determinants of a high peritoneal solute transport rate. After follow-up for 42.65±18.08 months, 30 patients (50.0%) had died. An increased D/Pcr increased the risk of all-cause mortality in patients with CAPD (p=0.018), but the dialysates IL-6 and Tie2 were not independent predictors of all-cause mortality (p>0.05).

Conclusion

Our results suggest that patients undergoing CAPD have a high peritoneal solute transport status with local peritoneal inflammation and angiogenesis. Increased D/Pcr is a relative risk factor for mortality and technique failure in patients undergoing CAPD.

A Uremic Goat Model Created by Subtotal Renal Artery Embolization and Gentamicin

A large animal model of (end-stage) kidney disease (ESKD) is needed for the preclinical testing of novel renal replacement therapies. This study aimed to create stable uremia via subtotal renal artery embolization in goats and induce a temporary further decline in kidney function by administration of gentamicin. Renal artery embolization was performed in five Dutch white goats by infusing polyvinyl alcohol particles in branches of the renal artery, aiming for the embolization of ~80% of one kidney and complete embolization of the contralateral kidney. Gentamicin was administered to temporarily further increase the plasma concentrations of uremic toxins. After initial acute kidney injury, urea and creatinine plasma concentrations stabilized 1.5 ± 0.7 months post-embolization and remained elevated (12 ± 1.4 vs. 5.6 ± 0.8 mmol/L and 174 ± 45 vs. 65 ± 5.6 µmol/L, resp.) during follow-up (16 ± 6 months). Gentamicin induced temporary acute-on-chronic kidney injury with a variable increase in plasma concentrations of small solutes (urea 29 ± 15 mmol/L, creatinine 841 ± 584 µmol/L, phosphate 2.2 ± 0.3 mmol/L and potassium 5.0 ± 0.6 mmol/L) and protein-bound uremic toxins representative of patients with ESKD. A uremic goat model characterized by stable moderate uremia was established via subtotal renal artery embolization with the induction of temporary severe acute-on-chronic kidney injury by the administration of gentamicin, allowing preclinical in vivo validation of novel renal replacement technologies.

ISPD recommendations for the evaluation of peritoneal membrane dysfunction in adults: Classification, measurement, interpretation and rationale for intervention

Lay summary

Peritoneal dialysis (PD) uses the peritoneal membrane for dialysis. The peritoneal membrane is a thin layer of tissue that lines the abdomen. The lining is used as a filter to help remove extra fluid and poisonous waste from the blood. Everybody is unique. What is normal for one person’s membrane may be very different from another person’s. The kidney care team wants to provide each person with the best dialysis prescription for them and to do this they must evaluate the person’s peritoneal lining. Sometimes dialysis treatment itself can cause the membrane to change after some years. This means more assessments (evaluations) will be needed to determine whether the person’s peritoneal membrane has changed. Changes in the membrane may require changes to the dialysis prescription. This is needed to achieve the best dialysis outcomes. A key tool for these assessments is the peritoneal equilibration test (PET). It is a simple, standardized and reproducible tool. This tool is used to measure the peritoneal function soon after the start of dialysis. The goal is to understand how well the peritoneal membrane works at the start of dialysis. Later on in treatment, the PET helps to monitor changes in peritoneal function. If there are changes between assessments causing problems, the PET data may explain the cause of the dysfunction. This may be used to change the dialysis prescription to achieve the best outcomes. The most common problem with the peritoneal membrane occurs when fluid is not removed as well as it should be. This happens when toxins (poisons) in the blood cross the membrane more quickly than they should. This is referred to as a fast peritoneal solute transfer rate (PSTR). Since more efficient fluid removal is associated with better outcomes, developing a personal PD prescription based on the person’s PSTR is critically important. A less common problem happens when the membrane fails to work properly (also called membrane dysfunction) because the peritoneal membrane is less efficient, either at the start of treatment or developing after some years. If membrane dysfunction gets worse over time, then this is associated with progressive damage, scarring and thickening of the membrane. This problem can be identified through another change of the PET. It is called reduced ‘sodium dip’. Membrane dysfunction of this type is more difficult to treat and has many implications for the individual. If the damage is major, the person may need to stop PD. They would need to begin haemodialysis treatment (also spelled hemodialysis). This is a very important and emotional decision for individuals with kidney failure. Any decision that involves stopping PD therapy or transitioning to haemodialysis therapy should be made jointly between the clinical team, the person on dialysis and a caregiver, if requested. Although evidence is lacking about how often tests should be performed to determine peritoneal function, it seems reasonable to repeat them whenever there is difficulty in removing the amount of fluid necessary for maintaining the health and well-being of the individual. Whether routine evaluation of membrane function is associated with better outcomes has not been studied. Further research is needed to answer this important question as national policies in many parts of the world and the COVID-19 has placed a greater emphasis and new incentives encouraging the greater adoption of home dialysis therapies, especially PD. For Chinese and Spanish Translation of the Lay Summary, see Online Supplement Appendix 1.

Key recommendations

Guideline 1:

A pathophysiological taxonomy: A pathophysiological classification of membrane dysfunction, which provides mechanistic links to functional characteristics, should be used when prescribing individualized dialysis or when planning modality transfer (e.g. to automated peritoneal dialysis (PD) or haemodialysis) in the context of shared and informed decision-making with the person on PD, taking individual circumstances and treatment goals into account. (practice point)

Guideline 2a:

Identification of fast peritoneal solute transfer rate (PSTR): It is recommended that the PSTR is determined from a 4-h peritoneal equilibration test (PET), using either 2.5%/2.27% or 4.25%/3.86% dextrose/glucose concentration and creatinine as the index solute. (practice point) This should be done early in the course dialysis treatment (between 6 weeks and 12 weeks) (GRADE 1A) and subsequently when clinically indicated. (practice point)

Guideline 2b:

Clinical implications and mitigation of fast solute transfer: A faster PSTR is associated with lower survival on PD. (GRADE 1A) This risk is in part due to the lower ultrafiltration (UF) and increased net fluid reabsorption that occurs when the PSTR is above the average value. The resulting lower net UF can be avoided by shortening glucose-based exchanges, using a polyglucose solution (icodextrin), and/or prescribing higher glucose concentrations. (GRADE 1A) Compared to glucose, use of icodextrin can translate into improved fluid status and fewer episodes of fluid overload. (GRADE 1A) Use of automated PD and icodextrin may mitigate the mortality risk associated with fast PSTR. (practice point)

Guideline 3:

Recognizing low UF capacity: This is easy to measure and a valuable screening test. Insufficient UF should be suspected when either (a) the net UF from a 4-h PET is <400 ml (3.86% glucose/4.25% dextrose) or <100 ml (2.27% glucose /2.5% dextrose), (GRADE 1B) and/or (b) the daily UF is insufficient to maintain adequate fluid status. (practice point) Besides membrane dysfunction, low UF capacity can also result from mechanical problems, leaks or increased fluid absorption across the peritoneal membrane not explained by fast PSTR.

Guideline 4a:

Diagnosing intrinsic membrane dysfunction (manifesting as low osmotic conductance to glucose) as a cause of UF insufficiency: When insufficient UF is suspected, the 4-h PET should be supplemented by measurement of the sodium dip at 1 h using a 3.86% glucose/4.25% dextrose exchange for diagnostic purposes. A sodium dip ≤5 mmol/L and/or a sodium sieving ratio ≤0.03 at 1 h indicates UF insufficiency. (GRADE 2B)

Guideline 4b:

Clinical implications of intrinsic membrane dysfunction (de novo or acquired): in the absence of residual kidney function, this is likely to necessitate the use of hypertonic glucose exchanges and possible transfer to haemodialysis. Acquired membrane injury, especially in the context of prolonged time on treatment, should prompt discussions about the risk of encapsulating peritoneal sclerosis. (practice point)

Guideline 5:

Additional membrane function tests: measures of peritoneal protein loss, intraperitoneal pressure and more complex tests that estimate osmotic conductance and ‘lymphatic’ reabsorption are not recommended for routine clinical practice but remain valuable research methods. (practice point)

Guideline 6:

Socioeconomic considerations: When resource constraints prevent the use of routine tests, consideration of membrane function should still be part of the clinical management and may be inferred from the daily UF in response to the prescription. (practice point)

Evaluation of a system for sorbent-assisted peritoneal dialysis in a uremic pig model

A system for sorbent-assisted peritoneal dialysis (SAPD) has been developed that continuously recirculates dialysate via a tidal mode using a single-lumen peritoneal catheter with the regeneration of spent dialysate by means of sorbents. SAPD treatment may improve plasma clearance by the maintenance of a high plasma-to-dialysate concentration gradient and by increasing the mass transfer area coefficient (MTAC) of solutes. The system is designed for daily 8-hr treatment (12 kg, nighttime system). A wearable system (2.3 kg, daytime system) may further enhance the clearance of phosphate and organic waste solutes during the day. Uremic pigs (n = 3) were treated with the day- (n = 3) and nighttime system (n = 15) for 4-8 hr per treatment. Plasma clearance (Cl), MTAC, and total mass transport (MT) of urea, creatinine, phosphate, and potassium were compared with a static dwell (n = 28). Cl, MTAC, and MT of urea, creatinine, phosphate, and potassium were low in the pig as compared to humans due to the pig's low peritoneal transport status and could be enhanced only to a limited extent by SAPD treatment compared with a static dwell (nighttime system: Cl urea: ×1.5 (p = .029), Cl creatinine: ×1.7 (p = .054), Cl phosphate: ×1.5 (p = .158), Cl potassium: ×1.6 (p = .011); daytime system: Cl creatinine: ×2.7 (p = .040), Cl phosphate: ×2.2 (p = .039)). Sorbent-assisted peritoneal dialysis treatment in a uremic pig model is safe and enhances small solute clearance as compared to a static dwell. Future studies in humans or animal species with higher peritoneal transport should elucidate whether our SAPD system enhances clearance to a clinically relevant extent as compared to conventional PD.

Maximizing the Success of Peritoneal Dialysis in High Transporters

This article reviews the current understanding of high transport status in the peritoneal dialysis population and emphasizes survival can be improved for high transporters. To address the current state of knowledge on high peritoneal membrane transport, the negative impact of an increased peritoneal solute transport rate is first discussed. The potential downside of high transport status, notably on survival outcomes (as supported by registry data and meta-analysis), is highlighted. Based on recent advances and clinical studies, ways of maximizing the success of peritoneal dialysis treatment in high transporters are discussed, and management strategies are proposed.

What is the Optimal Fat Mass in Peritoneal Dialysis Patients?

The prevalence of obesity in peritoneal dialysis (PD) populations has risen dramatically since the mid-1980s. This epidemic has been driven by the increased prevalence of obesity in the general population, the increased risk of progression of chronic kidney disease to end-stage renal failure (ESRF) in obese subjects, the reduced probability of listing obese dialysis patients for renal transplantation, a paradoxical enhanced survival in at least some obese populations on dialysis as compared with non-obese ESRF patients, and a possible adipogenic effect of excessive peritoneal glucose absorption in PD. Although obesity has consistently been associated with improved outcomes in hemodialysis, conflicting results have been seen in PD. In general, an elevated body mass index (BMI) has been associated with a neutral or deleterious impact on PD outcomes, and the relationship appears to be explained predominantly by fat mass. Risk is also elevated in patients with a low BMI, such that the “optimal BMI” appears to lie between 20 kg/m2 and 25 kg/m2. The mechanisms underpinning the harmful effect of obesity appear to include increased peritonitis rate, proinflammatory effects, and a more rapid decline of residual renal function in obese patients. No proof exists that weight reduction engenders an improvement in outcome in PD patients, but the available studies suggest that cautious weight reduction is advisable. A few studies have demonstrated that clinically important and sustained weight reduction can be successfully achieved through a combination of individual meal plans, regular exercise, and substitution of icodextrin for dextrose in the once-daily long dwell.

Immune Dysfunction in Dialysis Patients—Prevention and Treatment Strategies

Immune dysfunction, resulting in infection or inflammation, or both, is closely associated with poor clinical outcome in end-stage renal disease patients. So far, no single measure can effectively address this condition, because many factors, such as uremia per se and dialysis treatment are involved in the pathogenesis. Our review focuses on currently available treatments and prevention options, and identifies future research needs.

APD or CAPD: one glove does not fit all

The use of Automated Peritoneal Dialysis (APD) in its various forms has increased over the past few years mainly in developed countries. This could be attributed to improved cycler design, apparent lifestyle benefits and the ability to achieve adequacy and ultrafiltration targets. However, the dilemma of choosing the superior modality between APD and Continuous Ambulatory Peritoneal Dialysis (CAPD) has not yet been resolved. When it comes to fast transporters and assisted PD, APD is certainly considered the most suitable Peritoneal Dialysis (PD) modality. Improved patients’ compliance, lower intraperitoneal pressure and possibly lower incidence of peritonitis have been also associated with APD. However, concerns regarding increased cost, a more rapid decline in residual renal function, inadequate sodium removal and disturbed sleep are APD’s setbacks. Besides APD superiority over CAPD in fast transporters, the other medical advantages of APD still remain controversial. In any case, APD should be readily available for all patients starting PD and the most important indication for its implementation remains patient’s choice.

Excessive salt intake increases peritoneal solute transport rate via local tonicity-responsive enhancer binding protein in subtotal nephrectomized mice

BACKGROUND

High peritoneal transport is associated with high mortality and technical failure in peritoneal dialysis (PD). Baseline peritoneal solute transport rate (PSTR) as measured by the peritoneal equilibration test (PET) within 6 months after PD initiation varies between patients. Sodium is reported to be stored in the skin or muscle of dialysis patients. This study investigated whether excessive salt intake in uremic mice caused peritoneal alterations without exposure to PD fluid.

METHODS

Sham-operated (Sham) and subtotal nephrectomized (Nx) mice were randomly given tap water or 1% sodium chloride (NaCl)-containing water for 8 weeks. PET was then performed to evaluate peritoneal function. Human mesothelial cell line Met-5A was used for in vitro studies.

RESULTS

We observed higher PSTR in Nx mice with 1% NaCl-containing drinking water (Nx + salt) compared with those with tap water (Nx + water), along with enhanced angiogenesis and inflammation in the peritoneum. Blockade of interleukin (IL)-6 signaling rescued peritoneal transport function in Nx + salt mice. In cultured Met-5A, additional NaCl in the medium upregulated IL-6 as well as vascular endothelial growth factor-A, associated with increased expression and nuclear translocation of tonicity-responsive enhancer binding protein (TonEBP). Knockdown of TonEBP lowered the induction caused by high tonicity. Peritoneal TonEBP expression was higher in Nx + salt mice, while removal of high-salt diet lowered TonEBP level and improved peritoneal transport function.

CONCLUSIONS

Excessive dietary salt intake caused peritoneal membrane functional and structural changes under uremic status. TonEBP regulated hypertonicity-related inflammatory changes and might play a crucial role in high baseline peritoneal transport.

Contribution of Early Failure to Outcome on Peritoneal Dialysis

Background

The technique failure rate on peritoneal dialysis (PD) remains high despite technical progress. There are no data concerning the contribution of early failure to outcome on PD.

Aim

To analyze the importance of early treatment failure in PD and to compare early with late failures with respect to reasons and predictors of risk for failure.

Methods

We performed a retrospective study of all patients admitted for PD from October 1983 to June 2005. The end point was PD failure-free survival. Differences between reasons for failure with respect to early (within 6 months) and late failure were analyzed. Multivariate associations of baseline covariates with early and late failure were investigated.

Results

We included 279 patients. 153 (55%) patients experienced PD failure: 97 (63%) of them had technique failure; 56 (37%) patients died due to non-PD-related causes. 29% ( n = 44) of all PD failures and 40% ( n = 39) of all technique failures occurred within 6 months. Catheter and psychosocial problems contributed more often to early than to late failure, whereas infections, leakages, and hernias contributed equally to early and late failure. Death was the predominant reason for late failure. Female sex was a risk factor for early failure and older age a risk factor for late failure. Higher cholesterol levels were associated with a decreased risk for both early and late failure.

Conclusion

The contribution of early failure to outcome on PD is important, as one third of all PD failures and 40% of all technique failures may occur within the first 6 months, as shown in our study. Due to the retrospective nature and the single-center character, the results cannot be generalized. However, it is important to enhance recognition of patients at high risk for early PD failure prior to initiation of PD, in order to avoid unnecessary surgical interventions and medical complications, and for rational resource allocation.

High Peritoneal Permeability is Not Associated with Higher Mortality or Technique Failure in Patients on Automated Peritoneal Dialysis

Background

Patients on continuous ambulatory peritoneal dialysis (CAPD) who have high small-molecule peritoneal transport have increased mortality.

Objective

To investigate the impact of baseline peritoneal transport characteristics on patient and technique survival in incident peritoneal dialysis (PD) patients, most of whom are on automated PD (APD), with the use of icodextrin.

Design

Retrospective observational cohort study.

Setting

A single PD unit.

Patients and Methods

193 new patients that began PD between January 2000 and September 2004, and had an initial peritoneal equilibration test within 6 months of commencement of PD. Patients were divided into low (L), low average (LA), high average (HA), and high (H) peritoneal transport groups. Death-censored technique failure and patient survival were examined.

Results

Of the 193 patients, 151 (78.1%) were on APD or on APD with icodextrin or on CAPD with icodextrin. At the end of 1, 3, and 5 years, patient survival was 91%, 82%, and 67% in LA group; 95%, 77%, and 69% in HA group; and 96%, 71%, and 71% in H group. Technique survival was 100%, 90%, and 77% in LA group; 96%, 84%, and 72% in HA group; and 92%, 87%, and 77% in H group. High peritoneal permeability did not predict worse patient survival or technique failure, while age, diabetes, a lower glomerular filtration rate, and high body mass index (≥ 30 kg/m2) were independent predictors of death.

Conclusion

This study suggests that higher peritoneal transport is not a significant independent risk factor for either mortality or death-censored technique failure. The favorable outcome for high transporters in this study may be due to improved management of volume status by the increased use of APD and the use of icodextrin-based dialysis fluid.

The Behavior of the Type of Peritoneal Transport in the Inflammatory and Oxidative Status in Adults Under Peritoneal Dialysis

Peritoneal dialysis (PD) is an alternative for managing the end-stage renal disease (ESRD). The peritoneal membrane (PM) is not just a membrane that passively responds to diffusion and convection. The characteristics of PM result in the peritoneal equilibrium test (PET) and with this test is possible to obtain the type of peritoneal transport (PT). The patient on PD can be classified in different types of PT as; Low, Low Average, High Average, and High. The aim of the study was to compare the inflammatory cytokines, oxidants, antioxidants, and oxidative DNA damage markers in the different types of PT. A cross-sectional analytical study of 77 adult PD patients was performed. Levels of lipoperoxides (LPO) were higher in all types of PT vs. healthy volunteer controls (HC) (p < 0.0001). Nitric oxide (NO) levels were found significantly down-regulated in all types of PT (p < 0.0001). The activity of the superoxide dismutase enzyme (SOD) was found to be significantly increased in all types of PT vs. the HC (p < 0.0001). The levels of the DNA repair enzyme were found to be decreased in all types of PT. The levels of the pro-inflammatory cytokines TNF-α, IL-6, the marker of oxidative DNA damage, 8-IP and the total antioxidant capacity (TAC) were all significantly decreased, contrary to the levels in HC, possibly by the clearance in the dialysis fluid in all types of PT or due to down-regulation of their expression. In conclusion, we found significant changes in markers of inflammation, oxidative stress, and oxidative damage to DNA in all types of PT; Low, low average, high average, and high PT in the values of D/P creatinine at 4 h compared to HC.

Connective tissue growth factor is correlated with peritoneal lymphangiogenesis

Lymphatic absorption in the peritoneal cavity may contribute to ultrafiltration failure in peritoneal dialysis (PD). Lymphatic vessels develop during PD-related peritoneal fibrosis. Connective tissue growth factor (CTGF, also called CCN2) is an important determinant of fibrotic tissue remodeling, but little is known about its possible involvement in lymphangiogenesis. In this study, we investigated the relationship between CTGF and peritoneal lymphangiogenesis. A positive correlation was observed between vascular endothelial growth factor-C (VEGF-C), a major lymphangiogenic growth factor, and the CTGF concentration in human PD effluents. CTGF expression was positively correlated with expression of lymphatic markers and VEGF-C in human peritoneal biopsies. We found a positive correlation between the increase in CTGF and the increase in VEGF-C in cultured human peritoneal mesothelial cells (HPMCs) treated with transforming growth factor-β1 (TGF-β1). The diaphragm is a central player in peritoneal lymphatic absorption. CTGF expression was also correlated with expression of VEGF-C and lymphatics in a rat diaphragmatic fibrosis model induced by chlorhexidine gluconate (CG). Furthermore, CTGF gene deletion reduced VEGF-C expression and peritoneal lymphangiogenesis in the mouse CG model. Inhibition of CTGF also reduced VEGF-C upregulation in HPMCs treated with TGF-β1. Our results suggest a close relationship between CTGF and PD-associated lymphangiogenesis.

Dialysate cell-free mitochondrial DNA fragments as a marker of intraperitoneal inflammation and peritoneal solute transport rate in peritoneal dialysis

BACKGROUND

Mitochondrial DNA (mtDNA) released into extracellular subsequent to cell injury and death can promote inflammation in patients and animal models. However, the effects of peritoneal dialysate cell-free mtDNA on intraperitoneal inflammation and peritoneal solute transport rate (PSTR) in peritoneal dialysis (PD) patients remain unclear.

METHODS

We select the incident patients who began PD therapy between January 1, 2009, and December 30, 2010. Peritoneal dialysate was collected at the time of peritoneal equilibration test. The cell-free mtDNA, IL-6, IL-17A, TNF-α and IFN-γ were measured. All patients were followed till December 2017. The results were compared with PSTR and patient survival.

RESULTS

One hundred and eighty-nine patients were included in the study. The average age was 47.1 ± 13.5 years, 55.6% of the patients were males. The average PSTR was 0.66 ± 0.12, the median dialysate mtDNA levels were 4325 copies/ul. The median concentrations of IL-6, IL-17A, TNF-α and IFN-γ were 25.9, 10.8, 25.8 and 17.9 pg/ml, respectively. We found that dialysate mtDNA was significantly correlated with PSTR (r = 0.461, P < 0.001), IL-6 (r = 0.568, P < 0.001), TNF-α (r = 0.454, P < 0.001) and IFN-γ (r = 0.203, P = 0.005). After adjustment for multiple covariates, dialysate mtDNA levels were independently correlated with IL-6 and PSTR. Dialysate mtDNA levels were not associated with patient survival.

CONCLUSIONS

We found that dialysate mtDNA levels correlated with the degree of intraperitoneal inflammatory status in PD patients. Peritoneal effluent mtDNA was an independent determinant of PSTR but did not affect patient survival.

An international Delphi survey helped develop consensus-based core outcome domains for trials in peritoneal dialysis

Shared decision-making about clinical care options in end-stage kidney disease is limited by inconsistencies in the reporting of outcomes and the omission of patient-important outcomes in trials. Here we generated a consensus-based prioritized list of outcomes to be reported during trials in peritoneal dialysis (PD). In an international, online, three-round Delphi survey, patients/caregivers and health professionals rated the importance of outcomes using a 9-point Likert scale (with 7-9 indicating critical importance) and provided comments. Using a Best-Worst Scale (BWS), the relative importance of outcomes was estimated. Comments were analyzed thematically. In total, 873 participants (207 patients/caregivers and 666 health professionals) from 68 countries completed round one, 629 completed round two and 530 completed round three. The top outcomes were PD-related infection, membrane function, peritoneal dialysis failure, cardiovascular disease, death, catheter complications, and the ability to do usual activities. Compared with health professionals, patients/caregivers gave higher priority to six outcomes: blood pressure (mean difference, 0.4), fatigue (0.3), membrane function (0.3), impact on family/friends (0.1), peritoneal thickening (0.1) and usual activities (0.1). Four themes were identified that underpinned the reasons for ratings: contributing to treatment longevity, preserving quality of life, escalating morbidity, and irrelevant and futile information and treatment. Patients/caregivers and health professionals gave highest priority to clinical outcomes. In contrast to health professionals, patients/caregivers gave higher priority to lifestyle-related outcomes including the impact on family/friends and usual activities. Thus, prioritization will inform a core outcome set to improve the consistency and relevance of outcomes for trials in PD.

Predictors of outcomes in patients on peritoneal dialysis: A 2-year nationwide cohort study

There has been no nationwide study of prognostic factors and outcomes in patients on peritoneal dialysis (PD) in Japan. We conducted a cohort study using data from the nationwide registry of the Japanese Society for Dialysis Therapy. We followed 8,954 prevalent PD patients for 2 years, 2014–2015. Cox proportional hazards regression analysis was used to determine factors that were independently associated with patient survival. Survival rates were compared between patients with and without diabetes after adjusting for potential confounders. During the 2-year study period, 893 (10.0%) of 8,954 patients died, 148 (1.6%) underwent kidney transplantation, and 2,637 (29.4%) were switched to hemodialysis; 5,276 (58.9%) patients were alive at the end of the study period. After multivariate adjustment, older age, longer duration of dialysis, presence of diabetes, cardiovascular comorbidity, use of 2.5% glucose dialysate, higher C-reactive protein and phosphate levels, and a lower serum albumin level were independently associated with increased hazard ratios for all-cause mortality. A combination of PD and hemodialysis was associated with a lower mortality rate. The new-onset cardiovascular event rate was significantly higher in the diabetes group than in the non-diabetes group (P < 0.0001). After adjusting for all variables, the hazard ratio was 1.509 (95% confidence interval 1.029–2.189, P = 0.036) in the diabetes group. Diabetes, older age, longer duration of dialysis, cardiovascular comorbidity, and inflammation were predictors of mortality in patients on PD.

Membrane transport status does not predict peritonitis risk in patients on peritoneal dialysis

AIM

The aim of this study is to determine whether peritoneal membrane transport status (MTS) is associated with peritonitis or poor peritoneal dialysis-related outcomes.

METHODS

This retrospective cohort study analysed data of incident adult patients on peritoneal dialysis in Western Sydney between 1 October 2003 and 31 December 2012. Only patients who underwent peritoneal equilibration and adequacy tests within 6 months of commencement were included. Kaplan-Meier survival curves for time until first peritonitis and time until composite endpoint of peritonitis, death or technique failure, censored for transplant, were constructed.

RESULTS

About 397 patients, mean age 58.8(+/-2SD29) years, body mass index (BMI) 26.6(+/-5) kg/m² and serum albumin 35.4(+/-5) g/L were included. About 59.2% had high/high-average peritoneal MTS; 45.8% were past and current smokers; 51.9% developed at least one episode of peritonitis; 7.6% changed to haemodialysis; 6.3% underwent transplantation; 8.8% died; and 25.4% remained free of the aforementioned events over a mean follow-up period of 22.5 months (range 0-115 months). Peritoneal MTS was not associated with time to first peritonitis (p = 0.67) or composite endpoint of peritonitis, death or technique failure (p = 0.12). Smoking and hypoalbuminaemia independently predicted time to first peritonitis. Past and current smokers had a hazard ratio of 1.38 (95% CI 1.03-1.86) for shorter time to first peritonitis, significant after adjustment for serum albumin (p = 0.033). Serum albumin <32 g/L had a hazard ratio of 1.74 (95% CI 1.13-2.67) for shorter time to first peritonitis, significant after adjusting for smoking (p = 0.012).

CONCLUSION

Smoking and hypoalbuminaemia, but not MTS, were associated with shorter time to first peritonitis and composite endpoint of peritonitis, death and technique failure.

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

BACKGROUND

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.

METHODS

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:PCr_4h]), was evaluated using multivariable, multilevel linear regression. Baseline peritoneal glucose exposure was also assessed as either a continuous or categorical variable.

RESULTS

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:PCr_4h (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:PCr_4h was seen in the patients receiving conventional PD solution, but not in those receiving biocompatible solution.

CONCLUSIONS

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.

Regimen-related Mortality Risk in Patients Undergoing Peritoneal Dialysis Using Hypertonic Glucose Solution: A Retrospective Cohort Study

OBJECTIVES

The main purpose of this study was to quantify the risk of mortality linked to various regimens of hypertonic peritoneal dialysis (PD) solution.

METHODS

A retrospective cohort study of patients using home-based PD was carried out. The prescribed regimen of glucose-based PD solution for all patients, determined on the basis of their individual conditions, was extracted from their medical chart records. The primary outcome was death. The treatment regimens were categorized into 3 groups according to the type of PD solution used: original PD (1.5% glucose), shuffle PD (1.5 and 2.5% glucose), and serialized PD (2.5 and 4.5% glucose). Multivariate analysis (using the Weibull model) was applied to comprehensively examine survival probabilities related to the explanatory variable, while adjusting for other potential confounders.

RESULTS

Of 300 consecutive patients, 38% died over a median follow-up time of 30 months (interquartile range: 15-46 months). Multivariate analysis showed that a treatment regimen with continued higher-strength PD solution (serialized PD) resulted in a lower survival rate than when the conventional strength solution was used (adjusted hazard ratio, 2.6; 95% confidence interval, 1.6 to 4.6, p<0.01). Five interrelated risk factors (age, length of time on PD, hemoglobin levels, albumin levels, and oliguria) were significant predictors contributing to the outcome.

CONCLUSIONS

Frequent exposure to high levels of glucose PD solution significantly contributed to a 2-fold higher rate of death, especially when hypertonic glucose was prescribed continuously.

Different patterns of inflammatory and angiogenic factors are associated with peritoneal small solute transport and peritoneal protein clearance in peritoneal dialysis patients

Background

Both peritoneal small solute transport and peritoneal protein clearance are closely linked to outcomes in peritoneal dialysis (PD) patients. However, the associated factors of these two components are not fully understood so far. This study aimed to investigate the association between a panel of systemic and peritoneal inflammatory and angiogenic factors and peritoneal solute transport properties.

Methods

Stable PD patients in PD center of Renji Hospital, School of Medicine, Shanghai Jiao Tong University were enrolled in present study. Serum and overnight effluent markers including angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), sTie-2, VEGF, IL-6 and IL-10 were determined. Mass transfer area coefficient of creatinine (MTACcr) and peritoneal protein clearance (Prcl) were calculated. Multivariable linear regression was used to examine the association between these markers and MTACcr as well as Prcl.

Results

A total of 320 patients were enrolled in present study, which consisted of 166 (51.9%) males with a mean age of 56.8 ± 14.2 years and a median PD duration of 32.5 (9.0–56.3) months. Multiple regression analyses showed that BSA, history glucose exposure, dialysate IL-6 AR and dialysate Ang-1 AR were independent associated factors of MTACcr, while BSA and serum Ang-1 were independent associated factors of Prcl.

Conclusions

MTACcr representing peritoneal small-solute transport and Prcl representing peritoneal large molecular transport are associated with slightly different panels of inflammatory and angiogenic factors.

The Complement System in Dialysis: A Forgotten Story?

Significant advances have lead to a greater understanding of the role of the complement system within nephrology. The success of the first clinically approved complement inhibitor has created renewed appreciation of complement-targeting therapeutics. Several clinical trials are currently underway to evaluate the therapeutic potential of complement inhibition in renal diseases and kidney transplantation. Although, complement has been known to be activated during dialysis for over four decades, this area of research has been neglected in recent years. Despite significant progress in biocompatibility of hemodialysis (HD) membranes and peritoneal dialysis (PD) fluids, complement activation remains an undesired effect and relevant issue. Short-term effects of complement activation include promoting inflammation and coagulation. In addition, long-term complications of dialysis, such as infection, fibrosis and cardiovascular events, are linked to the complement system. These results suggest that interventions targeting the complement system in dialysis could improve biocompatibility, dialysis efficacy, and long-term outcome. Combined with the clinical availability to safely target complement in patients, the question is not if we should inhibit complement in dialysis, but when and how. The purpose of this review is to summarize previous findings and provide a comprehensive overview of the role of the complement system in both HD and PD.

Long-Term Peritoneal Dialysis Experience in Portugal

Peritoneal dialysis (PD) penetration varies widely. Since the beginning of this therapy, indications have changed and outcomes have improved. In Portugal, PD still remains clearly underutilized.

The results of a 20 year PD programme were evaluated: 312 cumulative patients, 48±16 years, 27% >60 years old, 27% diabetic, 59% with prior hemodialysis (HD). The main reason for admission was vascular access failure (48.7%). Admission due to patient preference has increased significantly between first and second decades of the programme (33% vs 47% (P<0.001)); 98 patients (31.4%) were treated with automated PD but this prescription increased to 43% of the active patients.

A total of 376 Tenckhoff catheters were surgically implanted, recently by the Popovich-Moncrief technique (77 catheters): the cumulative survival was 82%, 64% and 50% at 1, 3 and 5 years, respectively. A better catheter survival was found in the last decade (85.7%, 69.6%, 54.8% versus 77.3%, 55.5%, 40.2%, at 1, 3 and 5 years, respectively (P=0.007).

The patient and technique cumulative survivals were 91, 74, 55% and 85, 67, 41%, at 1, 3, and 5 years, respectively.

The main drop-out was to hemodialysis (35.8%), followed by death (23.7%), and transplantation (21.5%). Peritonitis and access-related infections caused 35% of the transfer to HD. Cardiovascular events caused 58% of deaths. The median PD retention was 35.5 months. The rate of peritonitis has decreased to one episode /30 patient months. Hospital admission has also decreased to 4.8 days/patient year.

This is a first report on long-term PD experience in Portugal. It has been an effective modality of renal replacement therapy, reflected by the growing patient preference in our PD programme. Experience, knowledge and new technical solutions have improved the outcomes.

Renal Association Clinical Practice Guideline on peritoneal dialysis in adults and children

These guidelines cover all aspects of the care of patients who are treated with peritoneal dialysis. This includes equipment and resources, preparation for peritoneal dialysis, and adequacy of dialysis (both in terms of removing waste products and fluid), preventing and treating infections. There is also a section on diagnosis and treatment of encapsulating peritoneal sclerosis, a rare but serious complication of peritoneal dialysis where fibrotic (scar) tissue forms around the intestine. The guidelines include recommendations for infants and children, for whom peritoneal dialysis is recommended over haemodialysis.Immediately after the introduction there is a statement of all the recommendations. These recommendations are written in a language that we think should be understandable by many patients, relatives, carers and other interested people. Consequently we have not reworded or restated them in this lay summary. They are graded 1 or 2 depending on the strength of the recommendation by the authors, and A-D depending on the quality of the evidence that the recommendation is based on.

Alteration of membrane complement regulators is associated with transporter status in patients on peritoneal dialysis

Introduction

A growing body of evidence from animal models and cell culture studies indicate an important role of a local regulatory complement system (CS) in peritoneal injury during peritoneal dialysis (PD). We investigated the expression of the local regulatory CS (reflected by CD46,CD55,CD59) in the peritoneal tissue of patients with different membrane function characteristics.

Patients and methods

Biopsies from the parietal peritoneum were taken from 24 patients on PD, 22 uremic patients prior to PD. PD patients were grouped according to the dialysate-to-plasma ratio of creatinine (D/P Cre) and ratio of dialysate glucose at 4 hours versus dialysate glucose at time zero (D/D0 glucose) into low or low-average peritoneal transport status (L/LA) and high-average or high-transport status (HA/H) groups. CD46, CD55, and CD59 RNA expression were analyzed by real-time polymerase chain reaction (RT-PCR). Further localization of membrane complement regulators (CRegs) and semiquantitatively analysis was done by immunohistochemistry (IHC).

Results

CD46 and CD59 expression were similar in all groups. CD55 expression was significantly decreased in the HA/H group compared to the L/LA group and to uremic controls (p < 0.05 and p = 0.05, respectively). No statistically significant differences in CD46, CD55, and CD55 expression were detected when considering the history of peritonitis. There was no statistically significant correlation between PD duration and the expressions of CD46, CD55, and CD59. IHC revealed strong CD46, CD55, and CD59 expression in mesothelial cells. CD55 and CD59 were additionally detected in the vasculature. Using IHC, CD46 was lower in PD patients compared to uremic controls (p>0.05), but there was no difference between the L/LA compared to the H/HA group. Moreover IHC confirmed decreased expression of CD55 in the HA/H group compared to the L/LA group and uremic controls (p<0.0001 and p = 0.0001, respectively).

Conclusion

CD55 expression is decreased in patients with fast transporter membrane function, whereas peritonitis and PD duration do not appear to alter CReg expression.

IL-6 promotes epithelial-to-mesenchymal transition of human peritoneal mesothelial cells possibly through the JAK2/STAT3 signaling pathway

Long-term peritoneal dialysis (PD) therapy results in functional and structural alteration of the peritoneal membrane, including epithelial-to-mesenchymal transition (EMT). Interleukin 6 (IL-6) is a local pleiotropic cytokine, hypothesized to play an important role in EMT. This study was designed to investigate the role of IL-6 in EMT and peritoneal membrane dysfunction in long-term PD patients by assessing the level of IL-6 in dialysate and exploring the relationship between IL-6, the related signaling pathway JAK2/STAT3, and EMT, using in vitro cellular and molecular techniques. Plasma and dialysate levels of IL-6 were significantly higher in PD ultrafiltration failure patients compared with patients without ultrafiltration failure and were negatively correlated with measures of PD adequacy. In vitro IL-6 treatment changed human peritoneal mesothelial cell phenotype from a typical cobblestone-like to a fibroblast-like appearance and increased cell viability. IL-6 treatment increased α-smooth muscle actin and vascular endothelial growth factor expression but decreased E-cadherin expression. IL-6 treatment activated the JAK/STAT signaling pathway. However, the JAK2/STAT3 inhibitor WP1066 prevented IL-6-induced activation of the JAK2/STAT3 pathway and EMT. We conclude that IL-6 promotes the EMT process, possibly by activating the JAK2/STAT3 signaling pathway. IL-6 may serve as a novel therapeutic target for preventing EMT, and preservation of the peritoneal membrane may arise from these studies.

Interleukin-6 trans-signalling induces vascular endothelial growth factor synthesis partly via Janus kinases-STAT3 pathway in human mesothelial cells

AIMS

Interleukin-6 (IL-6) is a vital inflammatory factor in the peritoneal cavity of peritoneal dialysis (PD) patients. Because intraperitoneal inflammation is closely associated with angiogenesis, we sought to explore the effect of IL-6 on vascular endothelial growth factor (VEGF) synthesis and its transduction pathway in mesothelial cells.

METHODS

Human mesothelial cells (Met-5A) were incubated with different concentrations of glucose and mannitol, and the effect of glucose and mannitol on the expression of IL-6 was determined. Then, the cells were stimulated by IL-6 with or without two soluble receptors of IL-6 (sIL-6R or sgp130), and VEGF synthesis was detected. Finally, the cells were incubated with IL-6/sIL-6R combined with or without the inhibitor of Janus kinases (JAK) AG490. The phosphorylation of the signal transducer and activator of transcription 3 (STAT3) and its intracellular translocation were examined.

RESULTS

1. High glucose and mannitol could upregulate IL-6 mRNA expression and IL-6 secretion in mesothelial cells significantly, and there was no difference of its effect between high glucose and mannitol. 2. Met-5A was a cell line with a single IL-6 receptor. The IL-6/sIL-6R complex induced VEGF synthesis of mesothelial cells, which was alleviated by sgp130 or AG490. IL-6 trans-signalling could induce the phosphorylation of STAT3, which is recruited to the cellular nucleus of Met-5A cells.

CONCLUSION

The present study might provide evidence that high glucose upregulates IL-6 synthesis in Met-5A cells, to some extent, depending on its osmolality and that IL-6 trans-signalling could induce VEGF synthesis partly dependent on the JAK/STAT3 pathway.

The Current State of Peritoneal Dialysis

Technical innovations in peritoneal dialysis (PD), now used widely for the long-term treatment of ESRD, have significantly reduced therapy-related complications, allowing patients to be maintained on PD for longer periods. Indeed, the survival rate for patients treated with PD is now equivalent to that with in-center hemodialysis. In parallel, changes in public policy have spurred an unprecedented expansion in the use of PD in many parts of the world. Meanwhile, our improved understanding of the molecular mechanisms involved in solute and water transport across the peritoneum and of the pathobiology of structural and functional changes in the peritoneum with long-term PD has provided new targets for improving efficiency and for intervention. As with hemodialysis, almost half of all deaths on PD occur because of cardiovascular events, and there is great interest in identifying modality-specific factors contributing to these events. Notably, tremendous progress has been made in developing interventions that substantially reduce the risk of PD-related peritonitis. Yet the gains have been unequal among individual centers, primarily because of unequal clinical application of knowledge gained from research. The work to date has further highlighted the areas in need of innovation as we continue to strive to improve the health and outcomes of patients treated with PD.

Possible role of IL-6 and TIE2 gene polymorphisms in predicting the initial high transport status in patients with peritoneal dialysis: an observational study

OBJECTIVES

The aim of this study was to investigate the effect of interleukin (IL)-6 and TIE2 gene polymorphisms on baseline peritoneal transport property.

DESIGN

An observational study.

SETTING

Renji Hospital in Shanghai, China.

PARTICIPANTS

This study included 220 patients with continuous ambulatory peritoneal dialysis (PD).

OUTCOME MEASURES

Patients were divided into 2 groups based on the results of an initial peritoneal equilibration test performed within 3 months of starting PD therapy: group 1 consisted of low/low average transporters (n=123), and group 2 consisted of high/high average transporters (n=97). We genotyped TIE2 and IL-6 polymorphisms and analysed their effects on baseline transport status.

RESULTS

The genotype AT in IL-6 Rs13306435 and the genotype CC in TIE2 Rs639225 were both negatively associated with a higher initial peritoneal transport status (IL-6 Rs13306435: OR=0.408, 95% CI 0.227 to 0.736; TIE2 Rs639225: OR=0.188, 95% CI 0.044 to 0.806).

CONCLUSIONS

IL-6 and TIE2 polymorphisms are associated with baseline peritoneal transport property.