Objective To investigate if intraperitoneal and systemic interleukin-6 (IL-6) and soluble IL-6 receptor (sIL-6R) are related to each other and to peritoneal solute transport rate (PSTR). Design Longitudinal study in retrospectively selected patients. Setting Peritoneal dialysis (PD) unit of a university-based hospital. Patients and Methods 31 PD patients on treatment with conventional glucose-based solutions participated in a longitudinal study. IL-6 and sIL-6R were measured in plasma and overnight effluent, both at baseline and after 12 ± 2 months on PD. C-reactive protein (CRP) and serum albumin were used as surrogate markers of inflammation. PSTR of small solutes was evaluated using the dialysate-to-plasma ratio (D/P) of creatinine after a 4-hour dwell; PSTR of large solutes was evaluated using the 24-hour D/P ratio of albumin. Results D/P creat increased over time (0.67 ± 0.15 vs 0.80 ± 0.11, p < 0.0001) and correlated to D/P albumin only at the baseline evaluation. Patients with plasma IL-6 ≥median had higher ( p < 0.005) D/P creat at baseline [0.74 (0.62 – 0.87)] compared to patients with IL-6 < median [0.57 (0.47 – 0.66)]. Dialysate IL-6 at baseline was also higher ( p < 0.05) in patients with plasma IL-6 ≥median [24.7 (16.5 – 38.5) pg/mL] compared to patients with IL-6 < median [14.1 (10 – 25.7) pg/mL]. Neither CRP nor albumin changed over time on PD, although they were closely linked to plasma IL-6 levels. A strong positive correlation was found between D/P creat and dialysate IL-6 (rho = 0.77, p < 0.0001) at baseline, but not at 1 year. In contrast, there was a significant correlation between D/P creat and dialysate sIL-6R (rho = 0.39, p < 0.05) at 1 year, but not at baseline. At 1 year, 17 patients with increasing PSTR had higher increases in dialysate IL-6 (28 ± 26 vs –21 ± 78 pg/mL, p < 0.05) and levels of dialysate sIL-6R (693 ± 392 vs 394 ± 274 pg/mL, p = 0.05) compared to patients with stable PSTR ( n = 11). Patients who had peritonitis presented higher baseline serum IL-6 concentration (6.8 ± 1.0 pg/mL) compared with patients without peritonitis (4.0 ± 0.6 pg/mL, p < 0.05). Finally, both at baseline and after 1 year, there were significant correlations between plasma and dialysate IL-6 (rho = 0.46, p < 0.05, and rho = 0.40, p < 0.05) respectively. Conclusions These findings indicate that, ( 1 ) intraperitoneal and systemic inflammation increase in PD patients during the first year of therapy; ( 2 ) intraperitoneal and systemic inflammation may be interrelated and the IL-6 system may be the link; ( 3 ) the IL-6 system (both intraperitoneal and systemic) is associated with PSTR, particularly in the early phase of PD treatment, in which small and large solute transport are linked. Signs of a transition between acute and chronic inflammation were observed in the follow-up evaluation. Inflammation may, at least in part, be responsible for the development of a high PSTR, and this could be one reason for the high mortality in patients with high PSTR.

Initial fast transport was not associated with systemic inflammation and atherosclerosis. In a population with preserved RRF and absence of baseline serious co-morbidity, it was not predictive of worse prognosis. Other determinants of early peritoneal fast transport deserve investigation.

Biofilms are commonly associated with an increased risk of patient infection. In peritoneal dialysis (PD), catheter associated infection, especially peritonitis, remains a clinically relevant problem. Although the presence of a biofilm is recognized in relapsing, repeat, and catheter-related peritonitis, it remains poorly characterized. In this review, an update on the role of biofilms in PD infections is presented. The emerging concept that host cells and tissue associated biofilms, in addition to the biofilms on the catheters themselves, contribute to the recalcitrance of infections is discussed. Furthermore, the evidence of biofilms on PD catheters, their developmental stages, and the possible influence of the PD environment are reviewed. The focus is given to ex vivo and in vitro studies that contribute to the elucidation of the interplay between host, microbial, and dialysis factors. The key issues that are still to be answered and the challenges to clinical practice are discussed.

Peritonitis remains a common complication of peritoneal dialysis (PD). The aim of this study was to analyze, in a PD center, long-term temporal trends in peritonitis rates, microbiology and outcomes. We treated 588 cases of peritonitis that occurred during 11,833.6 months at risk. Y-set and twin-bag disconnecting systems were introduced in 1990, mupirocin at the exit site in 2000 and fluconazole prophylaxis in 2005. Vancomycin and ceftazidime were the empiric protocol. Global and 5-year cohort rates were expressed as episodes/patient-year (ep/p-y). A global peritonitis rate reduction was found from 1.02 to 0.47 ep/p-y (p = 0.008). Poisson analyses performed in each of the subgroups of Gram-positive and Gram-negative peritonitis revealed no significant changes over time. No case of vancomycin resistance was identified. There was a downward trend in peritonitis-related hospitalization over time to 0.11 ep/p-y (p ≤ 0.001). Trend analysis showed a favorable, but changing evolution, highlighting the importance of accurate longitudinal PD center registry data and quality control.

BackgroundReduced free water transport (FWT) through ultrasmall pores contributes to net ultrafiltration failure (UFF) and should be seen as a sign of more severe functional deterioration of the peritoneal membrane. The modified peritoneal equilibration test (PET), measuring the dip in dialysate Na concentration, estimates only FWT. Our aim was to simultaneously quantify small-solute transport, FWT, and small-pore ultrafiltration (SPUF) during a single PET procedure.MethodsWe performed a 4-hour, 3.86% glucose PET, with additional measurement of ultrafiltration (UF) at 60 minutes, in 70 peritoneal dialysis patients (mean age: 50 ± 16 years; 61% women; PD vintage: 26 ± 23 months). We calculated the dialysate-to-plasma ratios (D/P) of creatinine and Na at 0 and 60 minutes, and the Na dip (DipD/PNa60,), the delta dialysate Na 0–60 (ΔDNa0–60), FWT, and SPUF.ResultsSodium sieving (as measured by ΔDNa0–60) correlated strongly with the corrected DipD/PNa60, ( r = 0.85, p < 0.0001) and the corrected FWT ( r = 0.41, p = 0.005). Total UF showed better correlation with FWT than with indirect measurements of Na sieving ( r = 0.46, p < 0.0001 for FWT; r = 0.360, p < 0.0001 for DipD/PNa60,). Corrected FWT fraction was 0.45 ± 0.16. A negative correlation was found between time on PD and both total UF and FWT ( r = -0.253, p = 0.035 and r = -0.272, p = 0.023 respectively). The 11 patients (15.7%) diagnosed with UFF had lower FWT (89 mL vs 164 mL, p < 0.05) and higher D/P creatinine (0.75 vs 0.70, p < 0.05) than did the group with normal UF. The SPUF correlated positively with FWT in the normal UF group, but negatively in UFF patients ( r = -0.709, p = 0.015). Among UFF patients on PD for a longer period, 44.4% had a FWT percentage below 45%.ConclusionsMeasurement of FWT and SPUF is feasible by simultaneous quantification during a modified 3.86% glucose PET, and FWT is a decisive parameter for detecting causes of UFF in addition to increased effective capillary surface.

Background and objectives Insulin resistance has been associated with cardiovascular disease in peritoneal dialysis patients. Few studies have addressed the impact of fast transport status or dialysis prescription on insulin resistance. The aim of this study was to test whether insulin resistance is associated with obesity parameters, peritoneal transport rate, and glucose absorption.Design, setting, participants, & measurements Insulin resistance was evaluated with homeostasis model assessment method (HOMA-IR), additionally corrected by adiponectin (HOMA-AD). Enrolled patients were prevalent nondiabetics attending at Santo António Hospital Peritoneal Dialysis Unit, who were free of hospitalization or infectious events in the previous 3 months (51 patients aged 50.4615.9 years, 59% women). Leptin, adiponectin, insulin-like growth factor-binding protein 1 (IGFBP-1), and daily glucose absorption were also measured. Lean tissue index, fat tissue index (FTI), and relative fat mass (rel.FM) were assessed using multifrequency bioimpedance. Patients were categorized according to dialysate to plasma creatinine ratio at 4 hours, 3.86% peritoneal equilibration test, and obesity parameters.Results Obesity was present in 49% of patients according to rel.FM. HOMA-IR correlated better with FTI than with body mass index. Significant correlations were found in obese, but not in nonobese patients, between HOMA-IR and leptin, leptin/adiponectin ratio (LAR), and IGFBP-1. HOMA-IR correlated with HOMA-AD, but did not correlate with glucose absorption or transport rate. There were no significant differences in insulin resistance indices, glucose absorption, and body composition parameters between fast and nonfast transporters. A total of 18 patients (35.3%) who had insulin resistance presented with higher LAR and rel. FM (7.3 [12.3, interquartile range] versus 0.7 [1.4, interquartile range], P,0.001, and 39.4610.1% versus 27.2611.5%, P=0.002, respectively), lower IGFBP-1 (8.267.2 versus 21.0616.3 ng/ml, P=0.002), but similar glucose absorption and small-solute transport compared with patients without insulin resistance. FTI and LAR were independent correlates of HOMA-IR in multivariate analysis adjusted for glucose absorption and small-solute transport (r=0.82, P,0.001).Conclusions Insulin resistance in nondiabetic peritoneal dialysis patients is associated with obesity and LAR independent of glucose absorption and small-solute transport status. Fast transport status was not associated with higher likelihood of obesity or insulin resistance.

Our experience documented improved PD clinical outcomes with the MP method of catheter implantation while assuring timely access management and logistic advantages.

Peritoneal dialysis maintenance without increasing volume status, nor major deleterious corporal composition trends, is feasible under careful therapy strategies. Longitudinal application of BIA may be a useful clinical tool to evaluate adequacy beyond Kt/V.