Correlation of Serum Asprosin Levels With Normalized Protein Catabolic Rate in Patients Receiving Peritoneal Dialysis Treatment

Background Peritoneal dialysis patients are malnourished due to loss of protein in the dialysate and inadequate dialysis, although they take additional calories every day during treatment. Many parameters are used to assess nutritional status, with normalized protein catabolic rate (nPCR) being one of the most common. Asprosin, a novel adipokine secreted by adipose tissue, peaks during fasting and induces hepatic glucose release through the activation of the G-protein-cAMP-PKA pathway, which has been indicated to have a curative effect on chronic inflammation. In this study, we aimed to investigate the relationship between asprosin levels and nutritional parameters in patients receiving peritoneal dialysis treatment as well as to investigate the applicability of more practical tests. Methodology A total of 70 peritoneal dialysis patients, 35 female (59%) and 24 male (41%), were included in the study. The mean age of the patients was 53 ± 14 years (range = 18-80 years), and the median peritoneal dialysis duration was 31.5 months (range = 20-56.2 months). The most common etiologic cause was hypertension (37%). Patients over 18 years of age who had been receiving peritoneal dialysis treatment for at least 24 months were included in the study. The correlation between patients' nPCR levels and serum asprosin, body mass index, and lipids was evaluated. Results The correlation between the level of nPCR and the serum asprosin level, body mass index, and lipids was evaluated. Patients with nPCR <0.815 were considered malnourished, and factors affecting malnutrition were determined by univariate analysis. Among the factors affecting malnutrition according to univariate analysis, those with p-value <0.05 were analyzed by multivariate analysis. Low asprosin level was one of the independent factors affecting malnutrition in patients (Exp(B) = 0.944, 95% confidence interval (CI) = 0.896-0.994). Other independent factors affecting malnutrition were Kt/V (Exp(B) = 0.018, 95% CI = 0.001-0.550) and residual renal function (Exp(B) = -0.004, 95% CI = 0.993-0.999). Conclusions There is a need for more accessible tests and reliable parameters to evaluate dialysis and nutritional deficiency in peritoneal dialysis patients. One possible hormone that could serve as a guide is asprosin.

Nutritional predictors associated with malnutrition in continuous ambulatory peritoneal dialysis patients

BACKGROUND

Currently in China, out of the total dialysis population, approximately 20% represents continuous ambulatory peritoneal dialysis (CAPD) and almost half of CAPD patients was affected by malnutrition. This study aimed to investigate the association between nutritional predictors and malnutrition with 5.1 years of dialysis according to the subjective global assessment (SGA) in continuous ambulatory peritoneal dialysis (CAPD) patients.

METHODS

A cross-sectional study was conducted from April 2013 to May 2018 and included 70 CAPD patients. The relationship between anthropometric and biochemical parameters with malnutrition was assessed by multiple logistic regression analysis.

RESULTS

The prevalence of malnutrition in CAPD patients was 52.9%. Our result revealed a 7.05-fold increased odds of malnutrition for patients with protein equivalent of total nitrogen appearance normalized to body weight (nPNA) < 1.0 g/kg per day (d) versus patients with normal nPNA (confidence interval (CI) 1.33-37.34; p < 0.05). Patients whose normalized protein catabolic rate (nPCR) was <1.2 g/(kg/d) had a significant positive association with malnutrition versus patients with normal nPCR (adjusted odds ratio (OR) 7.99; p < 0.05). Patients with dietary protein intake (DPI) < 1.0 g/(kg/d) had a higher likelihood of malnutrition than those with normal DPI (OR 12.73; p < 0.05). CAPD patients with upper arm circumference (UAC) < 23.2 cm had a high risk of malnutrition versus patients with normal UAC (OR 12.99; p < 0.05).

CONCLUSIONS

Our study suggested a close association between nPNA, DPI, nPCR, and UAC and malnutrition in CAPD patients. Further studies can be warranted the use of these variables as predictors and a malnutrition consequence among Chinese CAPD patients.

Normalized Protein Catabolic Rate Is a Superior Nutritional Marker Associated With Dialysis Adequacy in Continuous Ambulatory Peritoneal Dialysis Patients

Introduction: Current knowledge of the relationship between normalized protein catabolic rate (nPCR) and dialysis adequacy is limited. Our study aimed to explore the potential relationship between nPCR and dialysis adequacy.

Methods: In this cross-sectional study, we analyzed the association of nPCR with peritoneal dialysis adequacy in 266 continuous ambulatory peritoneal dialysis (CAPD) patients (mean age 48.6 ± 13.1 years; 50.8% male). The patients were divided into two groups: a dialysis inadequacy group (total weekly Kt/V urea < 1.70) and a dialysis adequacy group (total weekly Kt/V urea≥1.70). We then analyzed the correlation between dialysis adequacy and the patients' primary cause of end-stage renal disease, nutritional and inflammatory markers, and biochemical parameters. Multivariable logistic regression analysis was also used to identify risk factors for inadequate dialysis.

Results: We observed a significantly higher level of nPCR (0.98 ± 0.22 vs. 0.79 ± 0.18 g/kg/day, p < 0.001) in the dialysis adequacy group, whereas we observed no significant differences among other nutritional markers such as albumin, prealbumin, and transferrin. Correlation analyses revealed that dialysis adequacy was positively associated with residual glomerular filtration rate (rGFR), hemoglobin, serum calcium, and body mass index (BMI), while dialysis adequacy was negatively associated with leak-protein, uric acid, high-sensitivity C-reactive protein, interleukin-6, and serum phosphorus. Furthermore, a logistic regression analysis revealed that gender (male), nPCR <0.815 g/kg/day, higher weight, and rGFR <2.43 mL/min/1.73 m² were independent risk factors for inadequate dialysis.

Conclusion: Nutritional status is closely associated with dialysis adequacy. Among common nutritional markers, nPCR may be superior for predicting CAPD dialysis adequacy. Gender (male), nPCR <0.815 g/kg/day, higher weight, and rGFR <2.43 mL/min/1.73 m² are independent risk factors for dialysis inadequacy in CAPD patients.

Overnight Mesothelial Cell Exfoliation: A Magic Tool for Predicting Future Ultrafiltration Failure in Patients on Continuous Ambulatory Peritoneal Dialysis

⋄ Background

Continuous exposure of the peritoneal membrane to dialysis solutions during long-term dialysis results in mesothelial cell loss, peritoneal membrane damage, and thereby, ultrafiltration (UF) failure, a major determinant of mortality in patients on continuous ambulatory peritoneal dialysis (CAPD). Unfortunately, none of tests available today can predict long-term UF decline. Here, we propose a new tool to predict such a change.

⋄

Mesothelial cells from 8-hour overnight effluents (1.36% glucose dialysis solution) were harvested, co-stained with cytokeratin (a mesothelial marker) and TUNEL (an apoptotic marker), and were counted using flow cytometry in 48 patients recently started on CAPD. Adequacy of dialysis, UF, nutrition status, dialysate cancer antigen 125 (CA125), and a peritoneal equilibration test (3.86% glucose peritoneal dialysis solution) were simultaneously assessed and were reevaluated 1 year later.

⋄ Results

The numbers of total and apoptotic mesothelial cells were 0.19 ± 0.19 million and 0.08 ± 0.12 million cells per bag, respectively. Both numbers correlated well with the levels of end dialysate–to–initial dialysate (D/D0) glucose, dialysate-to-plasma (D/P) creatinine, and sodium dipping. Notably, the counts of cells of both types in patients with diabetes or with high or high-average transport were significantly greater than the equivalent counts in nondiabetic patients or those with low or low-average transport. A cutoff of 0.06 million total mesothelial cells per bag had sensitivity of 1 and a specificity of 0.75 in predicting a further decline in D/D0 glucose and a sensitivity of 0.86 and a specificity of 0.63 to predict a further decline in UF over a 1-year period. In contrast, dialysate CA125 and other measured parameters had low predictive values.

⋄ Conclusions

The greater the loss of exfoliated cells, the worse the expected decline in UF. The ability of a count of mesothelial cells to predict a future decline in UF warrants further investigation in clinical practice.

Are Three Exchanges Suitable for Asian Patients on Peritoneal Dialysis?

Phenomenal growth in continuous ambulatory peritoneal dialysis (CAPD) has occurred in the developing countries of Asia. In many regions in Asia, neither governments nor insurance companies fully cover treatment expenses for dialysis. Hence, patients in developing countries such as India, Bangladesh, Pakistan, and Nepal use just three 2-L exchanges daily. Typical practice in many centers is to do daytime CAPD with a dry night. Most of our Indian patients who are on three exchanges per day showed a Kt/V of 1.67 and 2-year survival rate of 60% with a normalized protein equivalent of nitrogen appearance of 0.73 – 0.80 g/kg daily. Vegetarians had a lower protein consumption rate and lower serum albumin levels. Peritoneal membrane characteristics vary among high, high average, and low average in various regions of Asia. The prevalence of diabetic nephropathy, with its associated comorbid conditions, as a major cause of end-stage renal disease in the Indian subcontinent explains the differences in the CAPD mortality rates between India and various Asian countries. Given the financial constraints in countries in Asia, small-volume dialysis of 6 L daily may be an acceptable compromise in some patient populations with a smaller body size and significant residual renal function; however, dialysis dose should be individualized according to the needs of each patient.

Dialysis adequacy in Chinese anuric peritoneal dialysis patients

PURPOSE

We aimed in this study to explore how lower-protein diet would affect dialysis adequacy in anuric peritoneal dialysis (PD) patients.

METHODS

Patients' demographic features were collected, namely age, gender, weight, height, underlying renal disease, and time on PD. Urea kinetic model was used to assess solute clearance. A consecutive 3-day dietary record was collected to evaluate dietary protein intake (DPI), and normalized protein nitrogen appearance (nPNA) was also calculated to reflect protein intake. Blood samples were collected to measure hemoglobin and biochemistry. Patient's nutritional status was assessed by biochemistry, handgrip strength, and subjective global assessment (SGA). Body fluid distribution was measured by body composition monitor.

RESULTS

Patients were 60.8 ± 14.92 years old, and the time on PD was 40.15 ± 22.90 months. Daily prescribed dialysis dose was 7,178 ± 1,326 mL. Kt/V was 1.6 ± 0.32. DPI was 0.8 ± 0.25 g/kg/day. nPNA was 0.9 ± 0.21 g/kg/day. Serum albumin was 39.42 ± 4.83 g/L. Prevalence of malnutrition (assessed by SGA) was 20.2 %. Serum phosphate and serum bicarbonate were 1.68 ± 0.47 and 27.16 ± 3.49 mmol/L, respectively. Systolic blood pressure and diastolic blood pressure were 123.4 ± 20.0 and 74.2 ± 12.6 mmHg, respectively. Patients with nPNA less than 0.6 had significantly lower serum albumin concentrations than the average, and patients with nPNA more than 1.2 g/kg/day had significantly higher levels of serum phosphate and serum urea than the average.

CONCLUSIONS

Our study suggested that anuric PD patients could achieve adequate dialysis even under lower solute clearance. And lower-protein diet contributed largely to adequate dialysis in these patients.

Impact of a genetic polymorphism of the interleukin-1 receptor antagonist on technique survival in peritoneal dialysis patients

BACKGROUND/AIMS

There is a clear association between one allele of the interleukin-1 receptor-antagonist gene (IL-1RN) and inflammatory diseases in which IL-1 is implicated. We evaluated patient survival and technique survival of peritoneal dialysis (PD) patients, while analyzing independent risk factors, in a PD program. We also tested the association between IL-1RN polymorphism, patient survival and technique survival.

METHODS

We retrospectively evaluated 129 Japanese CAPD patients undergoing initial treatment in eight centers in Japan. Using PCR, IL-1RN genotype and allele frequencies were determined, and clinical and biochemical variables were recorded at the start of PD. The relation of patient survival or technique survival with IL-1RN polymorphism and those variables was analyzed with a multivariate Cox's proportional-hazard model.

RESULTS

The frequencies of IL-1RN*1/IL-1RN*1 and IL-1RN*1/IL-1RN*2 genotypes were 84.5 and 15.5%, respectively. Median patient survival was 37.0 months, and overall patient survival was 92.8 and 87.9% at 2 and 5 years, respectively. Age, cardiovascular disease and serum albumin were found to be independent predictors of patient survival. Median technique survival was 32 months. PD failure occurred in 37 patients, with technique survival rates of 92.0 and 72.7% at 2 and 5 years, respectively. Serum albumin, peritonitis and the presence of the IL-1RN*2 genotype were found to be independent predictors of technique survival.

CONCLUSION

Serum albumin was the strongest predictive factor for mortality and technique failure in PD. Technique failure was also affected by IL-1RN polymorphism in this patient population.