Peritoneal Equilibration Test Research Articles

Baseline Peritoneal Membrane Transport Characteristics Are Associated with Peritonitis Risk in Incident Peritoneal Dialysis Patients.

The peritoneal equilibration test (PET) is a semi-quantitative measurement that characterizes the rate of transfer of solutes and the water transfer rate across the peritoneum in patients treated with peritoneal dialysis (PD). The results of the PET are used to maximize daily peritoneal ultrafiltration and solute clearances. Previous studies have shown that high transport status is associated with ultrafiltration failure, malnutrition, and reduced survival; however, the way in which peritoneum transport characteristics affect peritonitis risk is unknown. In the current cohort study, we recruited 898 incident-PD patients and used intention-to-treat analysis to test if baseline PET affected the subsequent 3-year peritonitis rate. Among all recruited PD patients, 308 (34.2%) developed peritonitis within three years. Multivariate Cox regression analysis showed that the high-transport group has the greatest peritonitis risk (HR 1.98, 95% CI: 1.08–3.62) even after an adjustment for demographics, comorbid diseases, and biochemical measurements. We concluded that a baseline high peritoneal membrane transport rate is an independent risk factor for peritonitis in incident PD patients.

L’assorbimento del glucosio in dialisi peritoneale: strumenti utili per il team multidisciplinare

Dialysis patients are often affected by protein energy wasting and the maintenance of an optimal nutritional state is a difficult goal to achieve. Moreover protein energy wasting is one of the strongest risk factors for mortality in chronic dialysis patients. To estimate glucose absorption in peritoneal dialysis is essential to determine patient’s dietary energy requirements and to prevent possible metabolic complications. The currently accepted methods of estimating glucose absorption are two. The first one is based on the average glucose absorption of continuous ambulatory peritoneal dialysis (CAPD) and is calculated with the Grodstein et al. formula. The second one is based on the Peritoneal equilibration test curves (D/D0 formula, Bodnar et al.) and takes into account transport characteristics. None of the two formulas perfectly calculated the absolute glucose absorption, even if the D/D0 is much closer to the true value, compared to Grodstein et al. formula. In this paper we described the multidisciplinary management experience of peritoneal dialysis patients, with a focus on the estimation of the patient’s energy requirements. Analyzing glucose absorption in a systematic way and monitoring the changes in glucose absorption during the time could significantly contribute to adjusting nutritional treatment. However it is always necessary to critically evaluate the results obtained by both formulas.

Peritoneal dialysis care during the COVID-19 pandemic, Thailand.

ProblemThe coronavirus disease 2019 (COVID-19) pandemic could affect health service provision of less urgent interventions, such as peritoneal dialysis for chronic kidney disease patients.ApproachTo assess how peritoneal dialysis centres in Thailand adapted their provision of care, we invited medical directors and peritoneal dialysis managers to respond to an online survey on 1 July 2021. We asked whether they had modified or deferred their training, catheter insertion or removal, intravenous supplements, follow-up and home visits, and workload.Local settingPatients needing dialysis receive peritoneal dialysis free of charge in Thailand. As of 31 December 2020, 240 peritoneal dialysis centres in Thailand have provided care to 32 284 patients.Relevant changesAt 24.6% (29/118) of centres, educational sessions for patients were modified. Catheter insertion continued at 71.9% (82/114) of centres. Few facilities (19.7%; 23/117) continued to perform peritoneal equilibration tests as usual. On-site intravenous injections were mostly transferred to health centres close to the patients’ homes. Most centres reduced their outpatient follow-up visits (51.7%; 61/118) and stopped visiting patients at home (66.9%; 79/118). Peritoneal dialysis nurses reported an increased workload at 62.7% (74/118) of centres, and in many instances (66.1%; 78/118) were providing nursing care to COVID-19 patients and administering COVID-19 vaccines.Lessons learntHealth-care providers altered clinical care activities to protect their patients from COVID-19. However, further evidence is needed on the consequences of such alteration in care. To prepare for future pandemics, actors need to explore nonconventional peritoneal dialysis care as well as financial and nonfinancial incentive mechanisms for such care.

Is peritoneal dialysis an effective treatment for cardiorenal syndrome with decompensated heart failure? A single center experience

Introduction and Objectives: ultrafiltration techniques have shown promise in the treatment of diuretic-resistant heart failure (HF). The aim of this study was to describe a center experience in treating refractory HF with peritoneal dialysis (PD). Methods: we performed a retrospective study of 14 patients presenting symptoms and signs of refractory congestive HF despite optimal pharmacological therapy, all excluded as candidates for heart transplantation. Baseline characteristics, laboratory data, Charlson score, and transthoracic doppler-echocardiogram results were collected. PD adequacy was evaluated through peritoneal equilibrium test results. Results: 12 patients were males and 2 females, with a median age of 72.13 years. The mean following time was 52.5 months. Symptoms of HF improved in 5 patients, with an upgrade of New York Heart Association (NYHA) Functional Classification and improvement in ejection fraction. NHYA remained the same in 6 PD treated individuals, despite and improvement of absolute ejection fraction. At the beginning of PD, the mean Charlson Score value was 5.7 ± 2.3, which reduced to 5.3 ± 2.6 by the end of observation time (p<0.01; r=0.984). Six patients presented one episode of decompensated heart failure needing hospitalization, with a median length of stay of 2 days. During the observation period 2 patients died, 1 from an acute hemorrhagic stroke and the other with a septic shock. Discussion: PD treatment in refractory HF seems to be effective since it improves quality of life and functional class.

Effluent N-terminal expressed in renal cell carcinoma/mesothelin predicts increased peritoneal permeability in patients undergoing peritoneal dialysis.

We investigated whether N-terminal and C-terminal products of expressed in renal cell carcinoma/mesothelin (N-ERC and C-ERC) in peritoneal effluent can predict peritoneal permeability in patients undergoing peritoneal dialysis (PD). Thirty-seven peritoneal effluent samples were obtained from 26 PD patients. High transport status was determined by the peritoneal equilibration test as a dialysate/plasma ratio of creatinine (D/P Cr) ≥ 0.81. Effluent cancer antigen 125 (CA125) was used as a reference. Effluent N-ERC concentration was better correlated with D/P Cr than effluent C-ERC or CA125 concentration. In multivariate analyses, effluent N-ERC and C-ERC, but not CA125, were significant predictors of high transport status after adjusting for age, PD duration, and residual renal Kt/V. ROC analysis showed that effluent N-ERC was the best predictor of high transport status among those three biomarkers. Effluent N-ERC predicts increased peritoneal permeability in patients undergoing PD.

Association between the appendicular lean mass index or handgrip strength and bone mineral density in patients undergoing peritoneal dialysis.

Background: Few studies have investigated the association between muscle mass and bone mineral density (BMD) in patients undergoing peritoneal dialysis (PD). We aimed to investigate the association between muscle mass or strength and BMD in patients undergoing PD.Methods: The data of all prevalent PD cases at a tertiary medical center between September 2017 and November 2020 were collected. Among all patients, 199 patients undergoing PD were finally analyzed. Baseline measurements including handgrip strength (HGS), appendicular lean mass (ALM) index, and BMD were obtained during a peritoneal membrane equilibration test. Patients with a T-score of ≤ -2.5 were categorized into the low BMD group.Results: The number of male patients was 113 (56.8%). Significant differences were observed in various indices, such as BMD, body composition parameters, and laboratory findings, between male and female patients. There was a stronger association between BMD and ALM index than between BMD and HGS in male patients (r = 0.432 and P < 0.001). The association between BMD and HGS was more definitive in female patients than in male patients (r = 0.357 and P = 0.001). Univariate and mutivariate linear regression and AUROC analyses showed similar trends those obtained in correlation analyses.Conclusion: The present study demonstrated that BMD is associated with the ALM index in male patients and with HGS in female patients undergoing PD.

Single peritoneal dialysis centre observations of treatment adequacy, anemia treatment, inflammation, mineral bone disease, and peritonitis rate – In patients undergoing continuous ambulatory peritoneal dialysis versus automated peritoneal dialysis

Purpose: Peritoneal dialysis was introduced to our centre in 1998. The aim of our retrospective analysis was to evaluate the difference in treatment adequacy, erythropoietin requirements, serum haemoglobin, serum C–reactive protein (CRP) and serum intact parathyroid hormone (i–PTH) levels, and episodes of peritonitis in patients switching from continuous ambulatory peritoneal dialysis (CAPD) to automated peritoneal dialysis (APD). We introduce peritoneal dialysis as a method of treatment for end–stage renal disease and the results of a retros-pective analysis.&#x0D; Methods: From May 1998 to December 2013, we retrospectively reviewed 12 patients (9 males and 3 females; mean age, 52.8±11.7 years) who switched from CAPD to APD. According to the peritoneal equilibration test, 75% of the patients were high transporters. We compared thetwo periods regarding peritoneal treatment adequacy number (Kt/V), erythropoietin requirements, serum haemoglobin, and CRP and i–PTH levels. We analysed the episodes of peritonitis during the CAPD and APD periods.&#x0D; Results: The average time spent on CAPD was 747.1±1028.2 days, and the average time spent on APD was 1300.0±1042.0 days. For the CAPD period, the mean Kt/V was 2.13±0.43, the mean haemoglobin value was 117.8±6.2 g/l, the mean erythropoietin requirement was 5290.1±4641.4 IU/week, the mean CRP value was 8.7±9.3 mg/l, and the mean i–PTH value was 580.2±445.9 pg/ml. For the APD period, the mean Kt/V was 2.24±0.35, the mean haemoglobin value was 117.1±8.6 g/l, the mean erythropoietin requirement was 4829.9±4976.6 IU/week, the mean CRP value was 9.1±8.3 mg/l, and the mean i–PTH value was 550.5±400.0 pg/ml. When comparing the two treatment modalities with a paired samples test, we found no significant differences regarding time spent (p=0.273), Kt/V (p=0.159), haemoglobin concentration (p=0.804), erythropoietin requirements (p=0.303), and CRP (p=0.886) and i–PTH levels (p=0.802). Further, no difference in the rate of peritonitis episodes between both modalities was found.&#x0D; Conclusion: Both peritoneal dialysis modalities are equal with respect to treatment adequacy, erythropoietin requirements, serum haemoglobin concentration, CRP and i–PTH levels, and peritonitis episodes.

Influencia del volumen peritoneal residual en los resultados de la prueba de equilibrio peritoneal. Estudio prospectivo

BackgroundCategorization of the capacity of ultrafiltration during a peritoneal equilibration test (PET) is a usual step during the monitoring of peritoneal transport characteristics of peritoneal dialysis (PD) patients. Quantifying the peritoneal residual volume (Vr) after the dwell preceding the PET (Vrpre) and at the end of the test (Vrpost) could help to improve the accuracy of the estimation of this variable. MethodFollowing a prospective design, we calculated Vrpre and Vrpost in 116 patients, incident or prevalent on DP, who underwent one or two (n=27) PET with 3.86/4.25% glucose-based PD solutions and complete drainage at 60min. We evaluated the consistency of Vr by comparing Vrpre and Vrpost, as also these two parameters in repeated tests. We scrutinized potential associations between demographic and clinical factors, on one side, and the amount of Vr on the other, as also the impact of correcting ultrafiltration during PET for Vr on the categorization of the capacity of ultrafiltration. ResultsAs a mean, Vrpost was larger than Vrpre. Consequently, correction of ultrafiltration for Vr resulted in significantly higher values than those obtained according to the standard procedure (494 vs 449mL, p<0.0005). We disclosed marked inconsistencies for different estimations of Vr in the same patients (Vrpre vs Vrpost and repeated PET studies). Moreover, no demographic or clinical variable was able to predict the amount of Vr. We observed a significant deviation (>200mL) between both methods of estimation of the capacity of utrafiltration in only 12.9% of the patients. However, 21.1% of the patients categorized as cases of ultrafiltration failure according to the standard procedure did not maintain this condition after correction for Vr. ConclusionsCorrection for Vr of the capacity of ultrafiltration during a PET carries, as a mean, a minor impact on the categorization of this parameter. However, the results of the test can be significantly affected in 12.9% of the cases. We have been unable to detect demographic or clinical predictors of Vr, which suggests a random component for the mechanics of single peritoneal exchanges. We suggest that Vr should be estimated at the time of categorizing the capacity of ultrafiltration, whenever inconsistencies during serial PET studies are detected.

Presence of galectin-3 in peritoneal dialysate. Does it have a role in the peritoneal membrane inflammatory process?

Peritoneal dialysis (PD) causes structural and functional changes in the peritoneal membrane, which are attributed to local inflammatory process. This study assessed the presence of galectin-3 (Gal-3), a known inflammatory modulator, in dialysate effluent and correlated its levels with markers of inflammatory process. Gal-3 levels in serum and dialysate effluent were measured in prevalent PD patients on morning visits (n= 27) or during peritoneal equilibration tests (PET, n= 16), it association with clinical and laboratory parameters, including dialysate/plasma creatinine (D/P creatinine) and interleukin-6 (IL-6) levels was analysed. Gal-3 levels in dialysate effluent correlated with D/P creatinine (0.663, p= 0.005) and dialysate effluent IL-6 levels (0.674, p= 0.002), but not with serum Gal-3 levels or dialysis vintage. Patients who were high transporters had higher Gal-3 levels in dialysate effluent, as compared to lower transporters. In multivariate regression analysis, dialysate IL-6 level was the strongest predictor of dialysate Gal-3 levels. This study found Gal-3 in dialysate effluent correlated with D/P creatinine and dialysate IL-6 levels. These findings may imply that Gal-3 has a role in the intraperitoneal inflammatory process. However, this needs to be investigated further.

An exploratory study of the relationship between systemic microcirculatory function and small solute transport in incident peritoneal dialysis patients.

The peritoneal capillary endothelium is widely considered to be the most influential structure in dictating the rate of small solute transport (SST) during peritoneal dialysis (PD). PD patients are at significant risk of systemic microcirculatory dysfunction. The relationship between peritoneal and systemic microcirculations in patients new to PD has not been well studied. We hypothesised that for patients on PD for less than 6 months, dysfunction in the systemic microcirculation would be reflected in the rate of SST. We recruited 29 patients to a cross-sectional, observational study. Rate of SST was measured using a standard peritoneal equilibration test. Laser Doppler Flowmetry was used to measure response to physical and pharmacological challenge (post-occlusive hyperaemic response and iontophoretic application of vasodilators) in the cutaneous microcirculation. Sidestream Darkfield imaging was used to assess sublingual microvascular density, flow and endothelial barrier properties. We found no moderate or strong correlations between any of the measures of systemic microcirculatory function and rate of SST or albumin clearance. There was however a significant correlation between dialysate interleukin-6 concentrations and both SST (rs = 0.758 p ≤ 0.0001) and albumin clearance (rs = 0.53, p = 0.01). In this study, systemic microvascular dysfunction did not significantly influence the rate of SST even early in patients PD careers. In conclusion, this study demonstrates that intraperitoneal factors particularly inflammation have a far greater impact on rate of SST than systemic factors.

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.

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.

The Ratio of Dialysate NGAL to Plasm NGAL (NGAL D/P) Can Reflect Peritoneal Transport in CAPD Patients

Methods: 20 CAPD anuria patients without peritonitis in our peritoneal dialysis center were recruited from July 2016 to July 2018. These patients were divided into high-transport peritoneum group and non-high transport peritoneum group according to peritoneal transport type. Patients from both groups received the same dialysis solutions and dialysis modality. Peritoneal transport type, serum C-reactive protein, peritoneal equilibrium test results, dialysate NGAL, plasm NGAL, the ratio of dialysate NGAL to plasm NGAL (D/P NGAL) from both groups were recorded. Spearman’s correlation coefficient was employed to examine the relations between variables. Receiver operating characteristic (ROC) curve analysis was used to calculate the area under the curve (AUC) for ratio of dialysate NGAL to plasm NGAL (D/P NGAL) and peritoneal creatinine to serum creatinine (D/P creatinine).

Overhydration May Be the Missing Link between Peritoneal Protein Clearance and Mortality

Introduction: Peritoneal protein loss (PPL) has been associated with mortality. Inflammation was assumed a putative cause with malnutrition as a consequence. Hydrostatic convection is a major drive for microvascular protein transport, but most studies in peritoneal dialysis (PD) patients overlooked this mechanism. An association between peritoneal protein clearance (PPCl) and venous congestion has been reported recently. The aim of this study was to explore the importance of fluid overload in PPCl in PD. Methods: Sixty-seven prevalent PD patients were assessed with peritoneal equilibration test and multifrequency bioelectrical impedance assessment (BIA). PPL and PPCl were calculated from simultaneously obtained 24-h peritoneal effluent. Results: PPL averaged 5.2 g/24 h. It was higher in patients on continuous treatment than in those without a long dwell. Significant associations between PPCl and BIA parameters of overhydration were found in both univariable and multivariable analyses. Lean mass index, partly dependent on hydration status, was associated with PPCl in univariable but not in multivariable analysis. A multiple linear model identified extracellular water excess and higher D/P creatinine as predictors of higher PPCl, independent of PD duration, type of PD, age, gender, albumin, cardiovascular disease, C-reactive protein, or lean mass index. Conclusions: The uni- and multivariable strong associations between fluid overload and PPCl support the importance of hydrostatic pressure-induced convection for PPCl. Also, peritoneal small solute transport was associated with PPCl. Both are amenable by adjusted dialysis prescription, especially focused on fluid status and avoidance of overhydration. The assumption of an association with inflammation and malnutrition was not confirmed.

Effluent Osteopontin levels reflect the peritoneal solute transport rate.

Long-term peritoneal dialysis (PD) is accompanied by low-grade intraperitoneal inflammation and may eventually lead to peritoneal membrane injury with a high solute transport rate and ultrafiltration failure. Osteopontin (OPN) is highly expressed through the stimulation of pro-inflammatory cytokines in many cell types. This study aimed to investigate the potential of OPN as a new indicator of peritoneal deterioration. One hundred nine continuous ambulatory PD patients were analyzed. The levels of OPN and IL-6 in peritoneal effluents or serum were analyzed by ELISA kits. The mean effluent OPN concentration was 2.39 ± 1.87 ng/mL. The OPN levels in drained dialysate were correlated with D/P Cr (p < 0.0001, R = 0.54) and D/D0 glucose (p < 0.0001, R = 0.39). Logistic regression analysis showed that the OPN levels in peritoneal effluents were an independent predictive factor for the increased peritoneal solute transport rate (PSTR) obtained by the peritoneal equilibration test (p < 0.001). The area under the receiver operating characteristic curve of OPN was 0.84 (95% CI: 0.75–0.92) in predicting the increased PSTR with a sensitivity of 86% and a specificity of 67%. The joint utilization of effluent OPN with age, effluent IL-6, and serum albumin further increased the specificity (81%). Thus, OPN may be a useful indicator of peritoneal deterioration in patients with PD.

MO710GALECTIN-3, IS IT A NEW PLAYER IN PERITONEAL INFLAMMATION AMONG PATIENTS UNDERGOING PERITONEAL DIALYSIS?

Abstract Background and Aims Peritoneal dialysis (PD) is a common used method for renal replacement therapy. Prolonged PD treatment causes structural and functional changes in the peritoneal membrane which are attributed to local inflammatory process in the peritoneal cavity. Galectin-3 (Gal-3) is a galactoside-binding lectin with pro-inflammatory and pro-fibrotic effects. The aim of this study was to assess correlation between Gal-3 serum and dialysate effluent levels with peritoneal membrane transport characteristics. Method Gal-3 levels in serum and dialysate effluent were measured simultaneously in prevalent PD patients in morning visit or during peritoneal equilibration test (PET). Gal-3 levels were correlated with clinical and laboratory parameters. Interlukin (IL) -6 levels were measured in dialysate effluent. Gal-3 mRNA and protein expression were evaluated after exposure of primary endothelial cell culture to several dialysate solutions. Results 37 PD patients were included in the study; mean age was 65.7±13.1 years, mean dialysis vintage was 17.5±13 months. Gal-3 levels in dialysate effluent correlated with peritoneal equilibration test (PET) results (0.663, p=0.005) and effluent IL-6 levels (0.674, p=0.002) but not with serum Gal-3 levels or dialysis vintage. Patients with high PET results had higher effluent Gal-3 levels as compared average low PET results. In multivariate regression analysis effluent IL-6 level was the most dominant predictor of effluent Gal-3 levels. Gal-3 mRNA and protein expression in primary endothelial cell culture were not affected by stimulation with dialysate solutions. Conclusion Our study demonstrated presence of Gal-3 within the dialysate effluent in PD patients. Gal-3 levels correlated with peritoneal membrane transport characteristics and effluent IL-6 levels suggesting a role in the inflammatory process within the peritoneal cavity.

FC 099DECLINING PERITONEAL HOST DEFENCES REVEALED BY EX-VIVO CYTOKINE RELEASE ASSAY OF PERITONEAL DIALYSIS EFFLUENT CELLS

Abstract Background and Aims Infectious complications occur in a significant proportion of PD patients, limiting long-term applicability. Reduced peritoneal immune-competence, caused by the continuous exposure to PD-fluids, has been described as a therapy-related pathomechanisms, prompting the need for a tool to assess the functional peritoneal immune status. We established an ex-vivo stimulation assay to test host defence mechanisms in only 9ml of PD-effluent. The aim of this study was to analyse basal inflammation and immune-competence in the general PD population at routine conditions to evaluate the assay as surrogate parameter of immune competence and linking it to PD vintage and clinical outcome parameters. Method 147 of 284 (51.8%) adult and paediatric PD patients treated between April 2013 and September 2020 at the local Department of Nephrology were included in the analysis. The study was approved by the local ethics committee and was conducted in accordance with the Declaration of Helsinki. Patients were exclusively treated with neutral pH/multi-chamber PD fluids during the glucose dwells. The majority of the 558 included PD-effluent samples were obtained during standard 4-hours peritoneal equilibration tests (PET) with 3.86% glucose containing PDF. Samples from the pre-PET dwell and at PET time points 1-hour and 4-hours were collected and immediately processed. Additional effluent samples were obtained during unscheduled hospitalization and in the event of an acute peritonitis. Effluent samples were collected directly from the drainage bags into standard 9 ml additive-free sample tubes. For ex-vivo stimulation, 100 ng/ml toll-like receptor (TLR) 4 agonist LPS and TLR2 agonist Pam3Cys were added to the effluent in the 9 ml collection tubes in duplicates and incubated at 37°C for 24h. Unstimulated samples kept in parallel were used as controls. IL-6 and TNF-α concentrations were measured with ELISA in the supernatants. Results Ex-vivo stimulation of peritoneal cells significantly increased the IL-6 and TNF-α release compared to unstimulated controls and resulted in a dwell-time dependent increase, with a significant lower cytokine released at the 1h PET time point. To assess local inflammation IL-6 levels of crude effluent were determined. IL-6 concentrations remained stable over time on PD. Interestingly, we were able to show higher IL-6 levels in CAPD patients in comparison to APD. As chronic exposure to PD-fluids has been shown to dampen the peritoneal immune competence, consecutive peritoneal effluent bags, obtained from patients were analysed. In this subcohort of 183 4h-PET effluents we found a decline in cytokine secretion with time on PD (IL-6 r=-0.27, p=0.00015, TNFa r=-0.25, p=0.00071). In a subgroup the ex-vivo cytokine release of effluent samples from patients with an acute peritonitis was assessed. IL-6 levels of acute peritonitis effluent samples did not differ from the stimulated IL-6 levels of effluent samples without acute peritonitis (2.45 pg/mL vs 2.31 pg/mL, p=0.85, t-test) suggesting that the assay seemingly represents the in-vivo host-defence cytokine release accurately. Conclusion The study provides evidence of a correlation of declining local host defence and duration of PD-therapy. It supports the hypothesis of PD duration-dependent progressive impairment of the ability of the peritoneal immune cells to secrete cytokines in response to a pathogenic stimulus and thereby dampening the global peritoneal immuno-competence. This suggests the utility of this clinically feasible ex-vivo induced cytokine-release assay in peritoneal effluent as a surrogate of the functional peritoneal immune competence. Future analyses need to evaluate the assay as a tool to predict common clinical outcomes and define reference values to facilitate stratification of patient populations, clinical staging and to guide novel therapeutic interventions.

MO714MEAN PLATELET VOLUME / PLATELET COUNT RATIO IN PERITONEAL DIALYSIS: ASSOCIATION TO PERITONEAL TRANSPORT STATUS

Abstract Background and Aims Mean platelet volume volume (MPV) is gaining scientific interest with regard to cardiovascular risk stratification. The MPV/platelet count ratio seems to be more specific than mean platelet volume alone as a surrogate parameter for platelet activation. The MPV/platelet ratio might be of interest in peritoneal dialysis (PD) as the distribution and integrity of endothelial – platelet interaction in the abdominal space determines its function. The aim of the study was to evaluate the associations between MPV/platelet ratio and peritoneal transport status. Method In 123 PD patients (median age 65 years) MPV and platelet count were measured together with anthropometric patient data and peritoneal function at catheter placement and after 6 months during the first peritoneal equilibration test (PET). MPV and platelet count were determined with a fully-automated hematological analyzer. Correlation analysis was performed. Results The MPV/platelet ratio decreased significantly from 3.99% at placement to 3.50% at the first PET (median values, Wilcoxon test p&amp;lt;0.001). Neither anthropometric data, nor creatinine clearance, nor BUN clearance, nor Kt/V (renal, peritoneal, total), nor erythrocyte sedimentation rate, nor C reactive protein were associated to MPV/platelet ratio. Only D/P urea and D/P creatinine were significantly correlated to MPV/platelet ratio (D/P urea r=0.223, p=0.01; D/P creatinine r=0.199, p=0.03). Slow transporters presented a significantly lower MPV/platelet ratio than average transporters (median values, 3.49% versus 3.83%, Mann-Whitney test p=0.03). Conclusion Peritoneal dialysis is reducing significantly the MPV/platelet ratio. Differences in MPV/platelet ratio are reflected in the peritoneal transport status at 6 months after dialysis start. The reduction of the MPV/platelet ratio might respect a reduced platelet and endothelial activation even in the abdominal space.

MO687FREE WATER TRANSPORT AND ABSOLUTE DIP OF DIALYSATE SODIUM CONCENTRATION: EARLY CLINICAL PARAMETERS FOR PERITONEAL FIBROSIS IN PD PATIENTS?

Abstract Background and Aims Reduction of peritoneal salt and water removal is an important cause of shortened patient and technique survival in peritoneal dialysis (PD). The aim of this study was to longitudinally analyze changes in fluid and solute transport parameters in PD patients during the first year of treatment, using peritoneal equilibration test (PET). Method Retrospective observational study of incident PD patients who underwent 4-hour 3.86% glucose PET with additional measurement of ultrafiltration at 1 hour, 1 month after PD initiation and 12 months later. Parameters of peritoneal transport such as dialysate-to-plasma ratio of creatinine (D/Pcreat), ultrafiltration at 1 and 4 hours, small-pore ultrafiltration (SPUF), free water transport (FWT), sodium removal and absolute dip of dialysate sodium concentration (ΔDNa) at 1 hour (as an expression of sodium sieving), were calculated. Serum cancer antigen 125 (CA-125) was also assessed. Clinical, analytical and demographic data were analyzed. Statistical analysis was performed using SPSS (Version 23 for Mac OSX). Results The average age of 16 incident PD patients was 58.69 ± 8.51 years, 10 (62.5%) were male and 5 (31.8%) were diabetic. Ten patients (62.5%) were on automated peritoneal dialysis (APD). One month after PD initiation, membrane characteristics were: D/P = 0.684 ± 0.589, total UF at 4h = 0.696 ± 0.283L, UF at 1h = 0.487 ± 0.162L, SPUF = 0.303 ± 0.359L, FWT = 0.207 ± 0.738L, %FWT = 51.855 ± 11.828%, sodium removal = 38.048 ± 16.087mmol/L and ΔDNa = 11.125 ± 3.34mmol/L. Average serum CA-125 was 51.206 ± 22.6U/mL. A paired sample t-test was performed to compare these parameters 1 and 12 months after PD initiation and revealed a statistically significant increase of 0.11± 0.196L (p=0.042) on SPUF and 18.607 ± 7.1mmol/L (p=0.019) on sodium removal. ΔDNa showed a decrease of 2.5 ± 0.743mmol/L (p=0.005) and % FWT of 11.782 ± 12.831% (p=0.002). FWT also showed a decrease of 0.168 ± 0.019L, total UF at 4h of 0.206 ± 0.142L and UF at 1h of 0.114 ± 0.243L, however did not reach statistical significance. D/Pcreat remained stable. CA-125 showed a mild decrease of 3.644 ± 22.364U/mL although not statistically significant. Pearson correlation revealed a positive correlation between the variation of total UF at 4h and the variation of FWT (r=0.553, p=0.026) and ΔDNa (r=0.503, p=0.047), but not with SPUF, sodium removal, D/Pcreat or CA-125, during the study follow-up period. Conclusion The reduction of FWT through aquaporins and, particularly, the reduction of ΔDNa as a sodium sieving measure, appear to be the first functional changes in peritoneal membrane, suggesting that fibrosis may begin soon after PD initiation. Our results indicate that FWT and ΔDNa can be used to access fibrotic peritoneal alterations earlier than other conventional parameters such as D/Pcreat.

MO688CALCIUM PHOSPHATE PRODUCT IN PERITONEAL DIALYSIS: A RISK FACTOR FOR TYPE I MEMBRANE FAILURE?

Abstract Background and Aims Type I membrane failure (T1MF), increased transport status with ultrafiltration, and solute removal inadequacy are among the most challenging issues in peritoneal dialysis (PD) continuity. Although quite common, the causes of T1MF are not fully understood. This study aims to identify risk factors associated with T1MF. Method This is a retrospective, single site, cohort study of incident adult peritoneal dialysis patients sampled between January 2000 and January 2020. Patients were classified as “increased transporters” who had two or more categories of a rise in peritoneal equilibration test (PET), and “stable transporters” who had had a rise of 1 or no categories from their baseline during follow-up. The four-hour dialysate/plasma creatinine ratio was used to classify PET categories. The study endpoint was five years for stable transporters, and at the time of two category rise in the PET test for increased transporters. Results Baseline demographics, diabetes frequency, residual renal function (RRF), non-phosphate baseline laboratory, parathormone levels, and PD modalities were similar between the increased transporters (n=48) and the stable transporters (n=93). Significantly more patients were using renin-angiotensin-aldosterone system (RAAS) blockers in stable transporters and high-glucose dialysates in increased transporters (p=0.03 and p&amp;lt;0.01). Icodextrin, calcitriol, calcium-based phosphate binder use, and the number of peritonitis episodes were similar between the groups. Increased transporters reached the endpoint in 3.9(±0.7) years. Increased transporters had a higher baseline phosphate than stable transporters (p=0.02). The frequency of patients with an RRF and groups’ mean RRF in ml were similar at the endpoint (p=0.37, p=0.13). Increased transporters had a significantly higher baseline and endpoint CaXP than stable transporters (p&amp;lt;0.01 and p=0.02). Baseline weekly peritoneal Kt/V and peritoneal creatinine clearance (PCrCl) were similar at baseline. Increased transporters had significantly lower endpoint peritoneal Kt/V and insignificantly lower endpoint PCrCl than stable transporters (p&amp;lt;0.01 and p=0.05). ΔUF was negative for increased transporters and positive for stable transporters. Age, diabetes, peritonitis episodes, RAAS blocker use, and PD modality were insignificant in Cox regression analysis. A CaXP of &amp;gt;55 was related to 2.51-fold, and high-glucose dialysates were associated with a 2.93-fold increased risk for a rise in transport status (p=0.01 and p&amp;lt;0.01). Mean follow-up was 7.0 (±3.9) years for stable transporters and 5.6 (±2.0) years for increased transporters. Technical survival was significantly higher in stable transporters (p=0.03). Conclusion Our study revealed a CaXP of &amp;gt;55 is a risk factor for a significant increase in transport status, presumably due to peritoneal calcification. The peritoneal Kt/V, PCrCl, and UF rates declined accordingly. The high-glucose dialysates are associated with a high risk in analyses. However, it is not possible to determine whether these solutions are the cause or the result of Type I membrane failure.