Protein and energy intake, nitrogen balance and nitrogen losses in patients treated with continuous ambulatory peritoneal dialysis

Protein and energy intake, nitrogen balance and nitrogen losses in patients treated with continuous ambulatory peritoneal dialysis. The aim of this investigation was to analyze factors which influence the dietary protein intake (DPI), the energy intake and the utilization of ingested protein, and to determine the relationship between various types of nitrogen losses in stable continuous ambulatory peritoneal dialysis (CAPD) patients. We performed 23 nitrogen balance (NB) studies of 6 to 11 days duration in 12 CAPD patients. One study was performed in all patients 3.4 ± 1.2 months after starting CAPD (early studies). The study was then repeated in nine patients after 12.1 ± 2.6 months, and two of these patients were studied again after 16 and 24 months, respectively (late studies). Before each NB study, the dietary intakes prior to the study were assessed in diaries and interviews. During a few days preceding the NB periods and during the NB periods each patient received an individualized diet composed so as to resemble the patients' spontaneously chosen diet regarding DPI and dietary energy intake (DEI). Total nitrogen, protein, urea and creatinine were analyzed in the dialysate and urine collected daily. Total nitrogen was also analyzed in the feces, collected over the whole NB period. Total nitrogen appearance (TNA), non-protein nitrogen appearance (NPNA) and urea nitrogen appearance (UNA) were calculated by correcting total nitrogen output, non-protein nitrogen output, that is, TNA minus the total protein losses (PL) and urea nitrogen output for changes in total body urea nitrogen. Glucose was determined in the collected dialysate and the daily glucose absorption was calculated. DPI varied between 0.62 and 2.09 g/kg/day, DEI between 21 and 42 kcal/kg/day and the peritoneal energy (glucose) intake (PEI) between 4 and 13 kcal/kg/day. DPI (but not DEI) correlated with Kt/Vurea and Kt/VCr and with total and renal clearances for urea and creatinine. NB (not corrected for “unmeasured” nitrogen losses) was positive in most studies, and it correlated with DPI and the total energy intake (TEI) in the early studies, but only with TEI in the late studies. DPI correlated with TNA, NPNA, UNA, non-protein-non-urea nitrogen loss and fecal nitrogen loss. UNA was highly correlated with TNA and NPNA (r = 0.95). We used data from 33 NB studies in CAPD patients (our present data combined with data from the literature) to calculate regression equations describing the relationship between TNA and NPNA, respectively, and UNA. Equations were derived by which the protein equivalent of TNA (PNA), that is, 6.25 TNA, and the protein equivalent of NPNA (PNPNA), that is, 6.25 NPNA, may be calculated from UNA which is directly measured. In stable CAPD patients, who are not strongly catabolic or anabolic, PNA may be used to estimate DPI and PNPNA may be used to estimate the net protein intake (DPI – PL)

High peritoneal residual volume decreases the efficiency of peritoneal dialysis

High peritoneal residual volume decreases the efficiency of peritoneal dialysis.BackgroundWide variation in peritoneal residual volume (PRV) is a common clinical observation. High PRV has been used in both continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis to minimize the time of a dry peritoneal cavity and to achieve better dialysis. However, the impact of PRV on peritoneal transport is not well established. In this study, we investigated the effect of PRV on peritoneal transport characteristics.MethodsPeritoneal effluents were collected in 32 male Sprague-Dawley rats after a five-hour dwell with 1.36% glucose solution. Forty-eight hours later, a four hour dwell using 25ml of 3.86% glucose solution and frequent dialysate and blood sampling was done in each rat with 125I-albumin as a volume marker. Before the infusion of the 3.86% glucose solution, 0 (control), 3, 6, or 12ml (8 rats in each group) of autologous effluent (serving as PRV) was infused to the peritoneal cavity.ResultsAfter subtracting the PRV, the net ultrafiltration was significantly lower in the PRV groups as compared with the control group: 13.4 ± 0.5, 12.0 ± 1.0, 11.7 ± 1.7, and 8.9 ± 0.4ml for 0, 3, 6, and 12ml PRV groups, respectively (P < 0.001). The lower net ultrafiltration associated with higher PRV was due to (a) a significantly lower transcapillary ultrafiltration rate (Qu) caused by a lower osmotic gradient, and (b) a significantly higher peritoneal fluid absorption rate (KE) caused by an increased intraperitoneal hydrostatic pressure. No significant differences were found in the diffusive mass transport coefficient for small solutes (glucose, urea, sodium, and potassium) and total protein, although the dialysate over plasma concentration ratios values were higher in the high-PRV groups. The sodium removal was significantly lower in the PRV groups as compared with the control group (P < 0.01).ConclusionOur results suggest that a high PRV may decrease net ultrafiltration through decreasing the Qu, which is caused by a decreased dialysate osmolality, and increasing the KE caused by an increased intraperitoneal hydrostatic pressure. The high volume of PRV also decreased the solute diffusion gradient and decreased peritoneal small solute clearances, particularly for sodium. Therefore, a high PRV may compromise the efficiency of dialysis with a glucose solution

Early vascular ageing and cellular senescence in chronic kidney disease

Chronic kidney disease (CKD) is a clinical model of premature ageing characterized by progressive vascular dis- ease, systemic inflammation, muscle wasting and frailty. The predominant early vascular ageing (EVA) process mediated by medial vascular calcification (VC) results in a marked discrepancy between chronological and bio- logical vascular age in CKD. Though the exact underlying mechanisms of VC and EVA are not fully elucidated, ac- cumulating evidence indicates that cellular senescence - and subsequent chronic inflammation through the senescence-associated secretary phenotype (SASP) - plays a fundamental role in its initiation and progression. In this review, we discuss the pathophysiological links between senescence and the EVA process in CKD, with focus on cellular senescence and media VC, and potential anti-ageing therapeutic strategies of senolytic drugs targeting cellular senescence and EVA in CKD.Swedish Research Council (grant no 2009-1068)European Union‘s Horizon 2020 research and innovation Program, Marie Skłodowska-Curie (grant agreement No 722609)International Network for Training on Risks of Vascular Intimal Calcification and roads to Regression of Cardiovascular Disease (INTRICARE)Baxter HealthcarePublishe

Hyaluronan prevents the decreased net ultrafiltration caused by increased peritoneal dialysate fill volume

Hyaluronan prevents the decreased net ultrafiltration caused by increased peritoneal dialysate fill volume. In the present study, we investigated (1) the effect of an increase in dialysate fill volume on peritoneal fluid and solute transport using a 1.36% glucose solution, and (2) the effect of intraperitoneal administration of hyaluronan on peritoneal transport characteristics when different fill volumes were used. A four-hour dwell study with frequent dialysate and blood sampling was performed in 26 male Sprague-Dawley rats with 131I albumin as the intraperitoneal volume marker. Each rat was injected intraperitoneally with 25ml (group Con25, N = 6) or 40ml (group Con40, N = 7) of 1.36% glucose dialysis solution alone or 25ml (group HA25, N = 6) or 40ml (Group HA40, N = 7) of 1.36% glucose dialysis solution with 0.01% hyaluronan. The peritoneal transport of fluid, glucose, urea, and total protein as well as the intraperitoneal hydrostatic pressure (IPP) with different fill volumes were evaluated. We found that IPP and peritoneal fluid absorption rate significantly increased with the increase in fill volume (P < 0.01), and therefore the net ultrafiltration volume was significantly lower in the Con40 group compared to the Con25 group despite a higher transcapillary ultrafiltration rate in the Con40 group. The addition of hyaluronan to dialysate significantly (P < 0.01) decreased the peritoneal fluid absorption rate (by 22% in HA25 vs. Con25 and by 29% in HA40 vs. Con40) and thus significantly increased the net peritoneal fluid removal. The diffusive mass transport coefficients for glucose, urea and total protein did not differ between the Con25 and Con40 groups or between the two hyaluronan groups as compared to their respective control groups. The peritoneal clearance of urea increased significantly in the high fill volume group (by 58% in Con40 vs. Con25) and in the two hyaluronan groups (by 21% in HA25 vs. Con25 and by 16% in HA40 vs. Con40). We conclude that: (1) An increase in dialysate fill volume using 1.36% glucose dialysis solution results in higher intraperitoneal hydrostatic pressure and higher peritoneal fluid absorption rate, and therefore lower net ultrafiltration. (2) Intraperitoneal addition of hyaluronan significantly decreases the peritoneal fluid absorption rate, and the decreasing effect is even more marked when a high fill volume is used. (3) Small solute clearances increase markedly with increases in fill volume, and then further increase by adding hyaluronan to the dialysate due to the increase in drainage volume. Thus, intraperitoneal administration of hyaluronan during a single peritoneal dialysis exchange may significantly increase the peritoneal fluid and solute removal by decreasing peritoneal fluid absorption, and may thereby prevent the decreased net ultrafiltration caused by an increase in dialysate fill volume

Study of the incidence of dialysis in São Paulo, the largest Brazilian city

OBJECTIVES: Chronic kidney disease is a major public health problem worldwide. In Brazil, approximately 100,000 patients (January 2012) receive renal replacement therapy. Nevertheless, data on dialysis incidence in the Brazilian population are scarce. This study aims to analyze the incidence of patients starting dialysis therapy in São Paulo City, the largest Brazilian metropolis. METHOD: This cohort study analyzed data from 9,994 patients starting hemodialysis or peritoneal dialysis funded by the Brazilian Public Health System during a 5-year period (2007-2011). Patient data for this study (recorded as electronic files) were obtained from the São Paulo City's Dialysis Regulatory Bureau, which regulates the allocation of patients requiring dialytic therapy. RESULTS: The dialysis incidence rates were 178, 174, 170, 185 and 188 per million population for the years 2007, 2008, 2009, 2010 and 2011, respectively. The incidence rates increased with age. Hypertension and diabetes were the main etiologies diagnosed. Hemodialysis was the chosen dialysis modality in the majority of patients (92.6%), whereas the percentage of patients referred for peritoneal dialysis decreased from 10.1% to 5.5%. CONCLUSION: The incidence of patients starting renal replacement therapy from 2007-2011 in São Paulo was stable but higher than the projected incidence for the entire country. The authors emphasize the need for further studies of the incidence of dialysis in the Brazilian population and for the creation of a Brazilian registry of dialysis patients, which would be a valuable tool for developing healthcare policies and renal replacement therapy strategies

Peritonitis: Episode Sequence, Microbiological Variation, Risk Factors and Clinical Outcomes in a North China Peritoneal Dialysis Center

Background/Aims: This study investigated peritonitis episodes with regard to time sequence, microbiological variation, factors associated with peritonitis and clinical outcomes in peritoneal dialysis (PD) patients. Methods: This single-center cohort study enrolled all incident patients who met the inclusion criteria at our center from June 1, 2012 to June 30, 2015 and who were followed until June, 2017. Clinical, biochemical characteristics and detailed data on peritonitis episodes, and hospitalizations were recorded. Results: A total of 218 episodes of peritonitis corresponding to a rate of 0.27 episode per patient-year were recorded. Gram positive bacteria, identified in 115 (52.8%) episodes, were the most common pathogens. The occurrence of enterococcus peritonitis increased from 15.1% of the first to 27.3% of the later episodes. Multivariate logistic regression showed that the presence of cardiovascular disease (CVD, odds ratio [OR] 2.177, 95% confidence interval [95%CI] 1.214–3.903, P=0.009), age≤ 55 (OR 2.282, 95%CI 1.062–4.906, P=0.035), non-independent operator (OR 0.440, 95%CI 0.206–0.938, P=0.034), lower values of potassium (OR=0.671,95%CI 0.472–0.954, P=0.026) and higher values of calcium-phosphate product (OR 1.410, 95%CI 1.065–1.868, P=0.017) were associated with peritonitis. Besides CVD (risk ratio [RR] 2.591, 95%CI 1.893–3.543, P&#x3c; 0.001) and non-independent operator (RR 0.583, 95%CI 0.439–0.776, P&#x3c; 0.001), a lower level of education (RR 0.641, 95%CI 0.487–0.842, P=0.001) was associated with higher peritonitis rates in log-linear analysis. Spearman analyses indicated that the time to the 1st episode was negatively related to the peritonitis rate (r=-0.291, P=0.001). Time-dependent Cox regression showed no association between the time to the 1st episode and patient survival (P=0.151). Patients with a high peritonitis rate (HPR) demonstrated worse technique survival (P&#x3c; 0.001). Conclusion: The present study has revealed several center-based features and modifiable risk factors for peritonitis. The presence of CVD and the need for assistance with PD operation not only increased the odds of peritonitis but were also associated with more peritonitis episodes. Time to first peritonitis was related to the peritonitis rate but not associated with patient survival. Patients with HPR had worse technique survival