Etiology of the Protein-Energy Wasting Syndrome in Chronic Kidney Disease: A Consensus Statement From the International Society of Renal Nutrition and Metabolism (ISRNM)

Variables de la desnutrición en pacientes en diálisis

Introducción: El paciente en diálisis va a sufrir una desnutrición proteico-calórica, con diferentes factores implicados en su aparición, lo cual se asocia con una elevadísima morbilidad cardiovascular y mortalidad. Se ha estimado una prevalencia de desnutrición en la población en hemodiálisis del 18-75%, siendo por tanto, un problema de especial relevancia en este tipo de pacientes. Objetivo: Realizar una revisión bibliográfica de los artículos científicos existentes sobre las variables que intervienen en la desnutrición del paciente en diálisis. Metodología: Se ha realizado una revisión bibliográfica mediante las bases de datos PubMed, Scielo, Pro- Quest. La búsqueda se ha realizado con términos Mesh, con una antigüedad no mayor de 5 años y con distintas palabras clave. Resultados: Se han revisado 19 artículos. La mayoría de los artículos fueron estudios observacionales y de revisión. Los factores que se asocian con desnutrición son la edad, pérdida de masa muscular, baja actividad física y dieta pobre en micronutrientes. Otro factor muy importante, es la inflamación. En cuanto a los métodos diagnósticos, son variados y diferentes, debido a la gran cantidad de variables que influyen en la desnutrición. Conclusiones: La desnutrición en pacientes en diálisis depende de distintas variables y no solamente de la dieta. Los factores que se asocian con desnutrición son mayor edad, pérdida de masa muscular, baja actividad física y dieta pobre en micronutrientes. Además, habría que añadir el doble papel que juega la inflamación en este proceso, pues puede ser tanto consecuencia como factor predisponente a la desnutrición.

N-Terminal Pro-B-Type Natriuretic Peptide as a Biomarker for Loss of Muscle Mass in Prevalent Hemodialysis Patients

Protein-energy wasting (PEW) is common in hemodialysis (HD) patients. A recent study demonstrated that a high level of N-terminal pro-B-type natriuretic peptide (NT-proBNP) may be associated with PEW in those patients. This prospective study aimed to assess the association of NT-proBNP with body composition and muscle loss. A cohort of prevalent HD patients (n = 238) was examined. Blood samples were obtained at baseline to measure high-sensitive C-reactive protein (hsCRP), interleukin-6 (IL-6), adiponectin and NT-proBNP. Nutritional status and changes in muscle mass were assessed by subjective global assessment, percentage creatinine generation rate (%CGR), creatinine index (CI) and lean body mass (LBM) estimated by dual-energy X-ray absorptiometry (DXA). The %CGR and CI were calculated five times for one year, and DXA was performed at baseline and one year later. Cardiac function was estimated by ultrasonography at baseline. NT-proBNP was significantly higher in HD patients with PEW. High NT-proBNP was associated with cardiac dysfunction, increased levels of hsCRP and IL-6, and serially decreased levels of the indexes for muscle mass. Multiple regression analysis adjusted with confounders showed that NT-proBNP was an independent predictor for decrease in LBM and serial lower levels of %CGR and CI. In conclusion, the present study demonstrated a novel association between NT-proBNP and muscle loss. NT-proBNP may be an independent biomarker for malnutrition in HD patients, especially in patients with muscles loss, regardless of chronic inflammation, cardiac dysfunction, or overhydration.

Effects of a Novel Nutritional Formula Enriched With Eicosapentaenoic Acid and Docosahexaenoic Acid Specially Developed for Tube-Fed Hemodialysis Patients

OBJECTIVE

To evaluate the effects of a nutritional formula enriched with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in tube-fed bedridden hemodialysis patients.

DESIGN

A prospective, multicenter, single-arm study.

SETTING

Koyukai Memorial Hospital, Orimoto Hospital, and Chofu Hospital, Japan.

SUBJECTS

Eleven tube-fed bedridden hemodialysis patients.

INTERVENTION

Patients were fed a nutritional formula enriched with EPA and DHA for 12 weeks.

MAIN OUTCOME MEASURES

Body weight; body mass index (BMI); serum levels of total protein, albumin, prealbumin, total cholesterol, triglyceride, and C-reactive protein (CRP); serum fatty acid composition.

RESULTS

Body weight; BMI; and serum levels of total protein, albumin, total cholesterol, triglyceride, and CRP at 12 weeks were not significantly different from baseline levels. Serum prealbumin, EPA, and DHA levels significantly increased after 12 weeks of treatment.

CONCLUSIONS

A nutritional formula enriched with EPA and DHA may be beneficial for nutritional management in tube-fed bedridden hemodialysis patients.

Sarcopenia, obesity, and mortality in US adults with and without chronic kidney disease

Introduction

In predialysis chronic kidney disease (CKD), the association of muscle mass with mortality is poorly defined, and no study has examined outcomes related to the co-occurrence of low muscle mass and excess adiposity (sarcopenic obesity).

Methods

We examined abnormalities of muscle and fat mass in adult participants of the National Health and Nutrition Examination Survey 1999–2004. We determined whether associations of body composition with all-cause mortality differed between participants with CKD compared to those without.

Results

CKD modified the association of body composition with mortality (P = 0.01 for interaction). In participants without CKD, both sarcopenia and sarcopenic obesity were independently associated with increased mortality compared with normal body composition (hazard ratio [HR] = 1.44, 95% confidence interval [CI] = 1.07–1.93, and HR = 1.64, 95% CI = 1.26–2.13, respectively). These associations were not present among participants with CKD. Conversely, obese persons had the lowest adjusted risk of death, with an increased risk among those with sarcopenia (HR = 1.43, 95% CI = 1.05–1.95) but not sarcopenic-obesity (P = 0.003 for interaction by CKD status; HR = 1.21, 95% CI = 0.89–1.65), compared with obesity.

Discussion

Sarcopenia associates with increased mortality regardless of estimated glomerular filtration rate, but excess adiposity modifies this association among persons with CKD. Future studies of prognosis and weight loss and exercise interventions in CKD patients should consider muscle mass and adiposity together rather than in isolation.

Association of Fluid Status and Body Composition with Physical Function in Patients with Chronic Kidney Disease

Background

Impairment of physical function and abnormal body composition are the major presentations in patients with chronic kidney disease (CKD). The aim of this study is to investigate the relationship between body composition and physical function in CKD patients.

Methods

This cross-sectional study enrolled 172 of CKD stages 1–5 from February 2013 to September 2013. Handgrip strength (upper extremity muscle endurance), 30-second chair-stand test (lower extremity muscle endurance) and 2-minute step test (cardiorespiratory endurance) were used as indices of physical function. Body composition, including fluid status (extracellular water/total body water, ECW/TBW), lean tissue index (LTI), and fat tissue index (FTI), was measured using a bioimpedance spectroscopy method.

Results

All patients with high ECW/TBW had lower handgrip strength and 30-second chair-stand than those with low ECW/TBW (P<0.001 and P = 0.002). CKD patients with high FTI had lower handgrip strength and 30-second chair-stand than those with low FTI (P<0.001 and P = 0.002). These patients with low LTI had lower handgrip strength than those with high LTI (P = 0.04). In multivariate analysis, high ECW/TBW was positively associated with decreased handgrip strength (β = -41.17, P = 0.03) in CKD patients. High FTI was significantly correlated with decreased times of 30-second chair-stand (β = -0.13, P = 0.01). There was no significant relationship between body composition and 2-minute step test.

Conclusions

Our results show a significant association of impaired upper and lower extremity muscle endurance with high fluid status and fat tissue. Evaluation of body composition may assist in indentifying physical dysfunction earlier in CKD patients.

Functional and structural abnormalities of the kidney and urinary tract in severely malnourished children - A hospital based study

Objectives:

The association of malnutrition and systemic diseases like chronic kidney disease (CKD) is well known. Various urinary tract abnormalities may be associated with malnutrition. So objective of current study was to determine the frequency of functional and structural urinary tract abnormalities in severely malnourished children admitted in Nutritional Rehabilitation Unit (NRU) of a tertiary care facility, Karachi.

Methods:

This descriptive cases series of 78 children was conducted in NRU from October 2014 - March 2015. All newly admitted children aged 2-60 months, diagnosed as Severe Acute Malnutrition (SAM) were studied and children with known kidney and urinary tract disorders were excluded. Detailed history, examination and investigations like serum creatinine, ultrasound kidney and urinary tract in addition to routine tests for SAM, were done. A proforma was used to collect demographic data, clinical history, physical findings, and radio-imaging and biochemical investigations. Glomerular filtration rate (GFR) was calculated using Schwartz equation. Data was analyzed using descriptive statistics.

Results:

Among 78 children, male to female ratio was equal. Mean age was 18±15.53 months and majority (79.48%) of children were below 24 months. Majority (82%) of children with SAM had marasmus whereas 18% had edematous malnutrition. Out of 78, 57 (73%) children had either functional (80.7%) and or structural (19.3%) abnormalities whereas 21(36.84%) had normal functional and structural status. Most common functional abnormality was subnormal GFR (<90ml/min/1.73 m²) found in all 46 children. Functional abnormities were more common in children below 24 months. Other functional disorders were Bartter syndrome, renal tubular acidosis and urinary tract infection (UTI) found in two cases each. Common structural abnormalities were echogenic kidneys (n=4, 36%), hydronephrosis (n=3, 27%), hypoplastic kidneys (n=3, 27%) and calculi (n=1, 9%). Subnormal GFR was also found in all cases with structural abnormalities. UTI was observed exclusively in two children among 11 with structural abnormalities.

Conclusion:

A high frequency of functional abnormalities and noticeable proportion of structural abnormalities of urinary tract were detected in children with SAM. Current finding suggest that multicenter study at national level may be undertaken to generate better data about prevalence of renal diseases in SAM.

The role of E3 ubiquitin-ligases MuRF-1 and MAFbx in loss of skeletal muscle mass

The ubiquitin-proteasome system (UPS) is the main regulatory mechanism of protein degradation in skeletal muscle. The ubiquitin-ligase enzymes (E3s) have a central role in determining the selectivity and specificity of the UPS. Since their identification in 2001, the muscle specific E3s, muscle RING finger-1 (MuRF-1) and muscle atrophy F-box (MAFbx), have been shown to be implicated in the regulation of skeletal muscle atrophy in various pathological and physiological conditions. This review aims to explore the involvement of MuRF-1 and MAFbx in catabolism of skeletal muscle during various pathologies, such as cancer cachexia, sarcopenia of aging, chronic kidney disease (CKD), diabetes, and chronic obstructive pulmonary disease (COPD). In addition, the effects of various lifestyle and modifiable factors (e.g. nutrition, exercise, cigarette smoking, and alcohol) on MuRF-1 and MAFbx regulation will be discussed. Finally, evidence of potential strategies to protect against skeletal muscle wasting through inhibition of MuRF-1 and MAFbx expression will be explored.

Hypogonadism associated with muscle atrophy, physical inactivity and ESA hyporesponsiveness in men undergoing haemodialysis

BACKGROUND

Testosterone deficiency (hypogonadism) is common among men undergoing haemodialysis, but its clinical implications are not well characterized. Testosterone is an anabolic hormone that induces erythrocytosis and muscle synthesis. We hypothesized that testosterone deficiency would be associated with low muscle mass, physical inactivity and higher dosages of erythropoietin-stimulating agents (ESA).

METHODS

Single-center cross-sectional study of 57 male haemodialysis patients. None of the patients was undergoing testosterone replacement therapy. Total testosterone was measured in serum. Body composition (by bioelectrical impedance analysis) and physical activity (by the use of pedometers) were assessed. Patients with testosterone levels below the normal range were considered hypogonadal.

RESULTS

Mean testosterone level was 321±146ng/dL; 20 patients (35%) were hypogonadal. Hypogonadal patients were older and had lower mean arterial blood pressure, higher interleukin-6 levels, lower lean body mass and higher fat body mass. A negative association between testosterone and normalized ESA dose was found in uni- and multivariate regression analyses. Testosterone levels directly correlated with lean body mass regardless of confounders. Hypogonadal patients had lower physical activity than their counterparts [2753±1784 vs. 4291±3225steps/day (p=0.04)]. The relationship between testosterone and physical activity was independent of age, comorbidities and inflammatory markers, but dependent on the proportion of muscle mass.

CONCLUSION

Hypogonadism is common in our male haemodialysis population and is associated with higher ESA doses, reduced muscle mass and lower physical activity. The link between low testosterone levels and physical inactivity may conceivably relate to reduced muscle mass due to inadequate muscle protein synthesis.

The effects of resistance exercise and oral nutritional supplementation during hemodialysis on indicators of nutritional status and quality of life

BACKGROUND

Protein-energy wasting (PEW) is common in patients undergoing hemodialysis (HD). Studies have assessed the positive effect of oral nutritional supplementation (ONS) or resistance exercise (RE) on nutritional status (NS) markers in patients undergoing HD.

METHODS

The aim of this study was to assess the effect of ONS and RE on NS and the quality of life (QOL) of 36 patients undergoing HD. In a randomized clinical trial, patients were divided into the following two groups: a control group (ONS) that received a can of ONS during their HD sessions and an intervention group (ONS + RE) that received a can of ONS and underwent a 40-min session of RE during their HD sessions. Both interventions lasted 12 weeks. The patients' anthropometric, biochemical, dietetic and bioelectrical impedance measurements as well as their QOL, evaluated using the Kidney Disease Quality of Life Short Form, were recorded.

RESULTS

At baseline, 55.5% of patients presented with PEW according to International Society of Renal Nutrition and Metabolism criteria (20 patients). We found statistically significant changes from baseline in both groups, such as increases in body weight, body mass index, midarm circumference, midarm muscle circumference, triceps skinfold thickness, fat mass percentage, handgrip strength, phase angle and serum albumin. A decrease in the prevalence of PEW was observed in both groups at the end of the intervention. A delta comparison between groups showed no statistically significant differences in the anthropometric and biochemical parameters. No significant improvement was observed in QOL and body composition measured by bioimpedance vector analysis. Dietary energy and protein intake increased significantly during the study period for all patients.

CONCLUSION

Oral nutritional supplementation during HD improves NS. The addition of RE during HD does not seem to augment the acute anabolic effects of intradialytic ONS on NS.

Nutrition, vitamin D, and health outcomes in hemodialysis: time for a feeding frenzy?

PURPOSE OF REVIEW

The role of nutrition and nutritional supplementation in dialysis recently has been reinvigorated, with small clinical trials exploring surrogate outcomes and larger epidemiologic studies generating treatment hypotheses requiring further study. The present review focuses on major aspects of nutrition and outcomes in hemodialysis patients: protein and calorie intake and nutritional vitamin D supplementation.

RECENT FINDINGS

Building on data from small studies, two large, quasi-experimental cohort studies showed significant mortality benefits associated with oral nutritional supplements provided during dialysis, suggesting potential options for ameliorating the protein-energy wasting that is common in dialysis patients and associated with poor outcomes. Multiple cohort studies suggest, both in the general population and in dialysis, that higher 25(OH) vitamin D levels are associated with improved outcomes; however, no major mortality trials exist in dialysis, and the smaller, surrogate studies conducted to date have been disappointing, showing no consistent benefits in surrogate outcomes including inflammation and anemia, despite appropriate responses of vitamin D levels to repletion.

SUMMARY

Nutritional interventions are attractive options for improving outcomes in dialysis patients. Nutritional protein supplements have considerable promise, but require further study, preferably in a large, generalizable pragmatic trial. Small nutritional vitamin D supplementation trials in dialysis have had disappointing results. In the absence of new data, there appears to be no role for routine assessment or repletion of 25(OH) vitamin D deficiency or insufficiency in dialysis.

Serum adiponectin and protein-energy wasting in predialysis chronic kidney disease

OBJECTIVE

Adiponectin (ADPN) has antiatherogenic, anti-inflammatory, and insulin-sensitizing effects. Serum ADPN levels are increased in patients with chronic kidney diseases (CKD), and higher ADPN is paradoxically a predictor of mortality in these patients. The aim of this study was to determine the association between serum ADPN levels and protein-energy wasting (PEW) in predialysis CKD.

METHOD

We examined serum ADPN concentrations and PEW in 1303 patients from the KNOW-CKD (KoreaN Cohort Study for Outcome in Patients With Chronic Kidney Disease) study. PEW was defined as the presence of three or more of the following four indicators: serum albumin <3.8 g/dL, body mass index <23 kg/m², urine creatinine excretion (UCE) below the lower quartile, and daily dietary protein intake <0.6 g/kg. We analyzed the association between PEW and ADPN using a multivariate regression model after adjustment for socioeconomic factors, comorbidities, and laboratory findings.

RESULTS

Among 1303 predialysis CKD patients, 72 (5.5%) had PEW. In multivariate logistic regression analysis, higher ADPN level was associated with PEW (odds ratio, 1.04; 95% confidence interval [CI], 1.01-1.08 by 1 μg/mL ADPN). The highest ADPN quartile was associated with PEW in comparison with the lowest quartile (odds ratio, 10.54; 95% CI, 1.28-86.74). In multiple linear regression with PEW indicators, ADPN was more strongly associated with UCE (β = -2.21; 95% CI, -4.13 to -0.28; R² = 0.67).

CONCLUSION

High ADPN is independently associated with PEW. Among PEW indicators, serum ADPN is closely associated with UCE as an indirect measure of muscle mass.

Abbreviated Steady State Intervals for Measuring Resting Energy Expenditure in Patients on Maintenance Hemodialysis

BACKGROUND

Indirect calorimetry requires a steady state (SS) protocol to determine measured resting energy expenditure (mREE). Achieving stringent criteria for an SS interval may be difficult for patients on maintenance hemodialysis (MHD), as they may become uncomfortable because of the test itself or their health status. The study aim was to explore if a shortened SS interval was within acceptable limits for bias and precision.

MATERIALS AND METHODS

For this cross-sectional secondary analysis, adults (N = 125) who received MHD thrice weekly were enrolled. The indirect calorimetry test was performed for a length of total time ≤30 consecutive minutes. SS was evaluated in accordance with intervals of 10, 5, 4, 3, and 2 minutes. The mREE at the 10-minute SS was compared with the mREE at 5, 4, 3, and 2 minutes, via t tests and Bland-Altman analysis, to determine degree of bias and level of agreement. The a priori alpha level was set at ≤0.5.

RESULTS

The sample was primarily male, African American, and non-Hispanic, with a mean ± SD age of 55.4 ± 12.2 years, who reported being on MHD for an average of 62.4 ± 74.3 months. None of the mREE measures were significantly different from that of the 10-minute SS interval. Seventy-two percent of the participants were able to achieve SS at the 10-minute interval, 83.2% at 5 minutes, 87.2% at 4 minutes, and 89.6% for both 3 and 2 minutes.

CONCLUSION

For patients on MHD, an abbreviated SS interval of <10 minutes (eg, 5 minutes) yielded valid mREE measurements.

High Dose Omega-3 Fatty Acid Administration and Skeletal Muscle Protein Turnover in Maintenance Hemodialysis Patients

BACKGROUND AND OBJECTIVES

Protein energy wasting and systemic inflammation are prevalent in maintenance hemodialysis (MHD) patients. Omega-3 (ω-3) fatty acids have anti-inflammatory properties and have been shown to improve protein homeostasis. We hypothesized that administration of high-dose (2.9 g/d) ω-3 would be associated with decreased muscle protein breakdown in MHD patients with systemic inflammation.

DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS

This is a substudy from a randomized, placebo-controlled study (NCT00655525). Patients were recruited between September 2008 and June 2011. Primary inclusion criteria included signs of chronic inflammation (average C-reactive protein of ≥5 mg/L over three consecutive measurements), lack of active infectious or inflammatory disease, no hospitalization within 1 month prior to the study, and not receiving steroids (>5 mg/d) and/or immunosuppressive agents. The primary outcomes were forearm muscle and whole body protein breakdown and synthesis before and after the intervention. The patients received ω-3 (n=11) versus placebo (n=9) for 12 weeks. Analysis of covariance was used to compare outcome variables at 12 weeks. Models were adjusted for a propensity score that was derived from age, sex, race, baseline high sensitivity C-reactive protein, diabetes mellitus, and fat mass because the groups were not balanced for several characteristics.

RESULTS

Compared with placebo, ω-3 supplementation was significantly associated with decreased muscle protein breakdown at 12 weeks (-31, [interquartile range, -98--13] versus 26 [interquartile range, 13-87] µg/100 ml per min; P=0.01), which remained significant after multivariate adjustment (-46, [95% confidence interval, -102 to -1] µg/100 ml per min). ω-3 Supplementation resulted in decreased forearm muscle protein synthesis while the rate in the placebo group increased; however, there is no longer a statistically significant difference in skeletal muscle protein synthesis or in net protein balance after multivariate adjustment. There was no statistically significant effect of ω-3 supplementation on whole body protein synthesis or breakdown.

CONCLUSIONS

High-dose ω-3 supplementation over 12 weeks in MHD patients with systemic inflammation was associated with attenuation of forearm muscle protein breakdown but did not influence skeletal muscle protein synthesis, skeletal muscle net protein balance or any component of the whole-body protein balance. These results should be interpreted cautiously given the imbalance in the two groups and the short duration of the intervention.

Intradialytic aerobic cycling exercise alleviates inflammation and improves endothelial progenitor cell count and bone density in hemodialysis patients

Inflammation, endothelial dysfunction, and mineral bone disease are critical factors contributing to morbidity and mortality in hemodialysis (HD) patients. Physical exercise alleviates inflammation and increases bone density. Here, we investigated the effects of intradialytic aerobic cycling exercise on HD patients. Forty end-stage renal disease patients undergoing HD were randomly assigned to either an exercise or control group. The patients in the exercise group performed a cycling program consisting of a 5-minute warm-up, 20 minutes of cycling at the desired workload, and a 5-minute cool down during 3 HD sessions per week for 3 months. Biochemical markers, inflammatory cytokines, nutritional status, the serum endothelial progenitor cell (EPC) count, bone mineral density, and functional capacity were analyzed. After 3 months of exercise, the patients in the exercise group showed significant improvements in serum albumin levels, the body mass index, inflammatory cytokine levels, and the number of cells positive for CD133, CD34, and kinase insert domain-conjugating receptor. Compared with the exercise group, the patients in the control group showed a loss of bone density at the femoral neck and no increases in EPCs. The patients in the exercise group also had a significantly greater 6-minute walk distance after completing the exercise program. Furthermore, the number of EPCs significantly correlated with the 6-minute walk distance both before and after the 3-month program. Intradialytic aerobic cycling exercise programs can effectively alleviate inflammation and improve nutrition, bone mineral density, and exercise tolerance in HD patients.

MICS, an easily ignored contributor to arterial calcification in CKD patients

In chronic kidney disease (CKD), simultaneous mineral and skeleton changes are prevalent, known as CKD-mineral bone disorder (CKD-MBD). Arterial calcification (AC) is a clinically important complication of CKD-MBD. It can increase arterial stiffness, which leads to severe cardiovascular events. However, current treatments have little effect on regression of AC, as its mechanisms are still unclear. There are multiple risk factors of AC, among which Malnutrition-Inflammation Complex Syndrome (MICS) is a new and crucial one. MICS, a combined syndrome of malnutrition and inflammation, generally begins at the early stage of CKD and becomes obvious in end-stage renal disease (ESRD). It was linked to reverse epidemiology and associated with increased cardiovascular mortality in ESRD patients. Recent data suggest that MICS can trigger CKD-MBD and accelerate the course of AC. In this present review, we summarize the recent understanding about the aggravating effects of MICS on AC and discuss the possible underlying mechanisms. A series of findings indicate that targeting MICS will provide a potential strategy for treating AC in CKD.

Reduction of carbamylated albumin by extended hemodialysis

Introduction Among conventional hemodialysis (CHD) patients, carbamylated serum albumin (C-Alb) correlates with urea and amino acid deficiencies and is associated with mortality. We postulated that reduction of C-Alb by intensive HD may correlate with improvements in protein metabolism and cardiac function. Methods One-year observational study of in-center nocturnal extended hemodialysis (EHD) patients and CHD control subjects. Thirty-three patients receiving 4-hour CHD who converted to 8-hour EHD were enrolled, along with 20 controls on CHD. Serum C-Alb, biochemistries, and cardiac MRI parameters were measured before and after 12 months of EHD. Findings EHD was associated with reduction of C-Alb (average EHD change -3.20 mmol/mol [95% CI -4.23, -2.17] compared to +0.21 [95% CI -1.11, 1.54] change in CHD controls, P < 0.001). EHD was also associated with increases in average essential amino acids (in standardized units) compared to CHD (+0.38 [0.08, 0.68 95%CI]) vs. -0.12 [-0.50, 0.27, 95% CI], P = 0.047). Subjects who reduced C-Alb more than 25% were found to have reduced left ventricular mass, increased urea reduction ratio, and increased serum albumin compared to nonresponders, and % change in C-Alb significantly correlated with % change in left ventricular mass. Discussion EHD was associated with reduction of C-Alb as compared to CHD, and reduction of C-Alb by EHD correlates with reduction of urea. Additional studies are needed to test whether reduction of C-Alb by EHD also correlates with improved clinical outcomes.

Astragalus polysaccharides decrease muscle wasting through Akt/mTOR, ubiquitin proteasome and autophagy signalling in 5/6 nephrectomised rats

ETHNOPHARMACOLOGICAL RELEVANCE

Existing evidences suggest that Radix Astragali and its polysaccharides composition (APS) can improve muscle mass, but the mechanisms need more research.

AIM OF THE STUDY

In this study, we aimed to examine the effects of APS on muscle wasting at molecular level in 5/6 nephrectomised rats.

MATERIALS AND METHODS

We performed 5/6 nephrectomy or sham operation in 160 6-week-old Sprague-Dawley rats, and feed animals with or without 2% APS for 155 days. After treatment, we compared the change of weight, muscle fibre, protein metabolism, pro-inflammatory factors (TNF-α, IL-15, CRP) and oxidative factors (MDA, SOD) among each group. In addition, we detected the Akt/mTOR, ubiquitin proteasome, autophagy signalling and AA transporters in vivo and in vitro.

RESULTS

Data in vivo show 2% APS could alleviate weight loss and improve protein metabolism in nephrectomised rats. The levels of serum pro-inflammatory factors and oxidative factors were restored by APS treatment. In molecular levels, APS restored Akt/mTOR, MAFbx, MuRF1, Atg7, LC3B-II/LC3B-I and SLC38A2 which changed in nephrectomised rats. Data in vitro show the optimal dose of APS is 0.2mg/mL, and SLC38A2 siRNA attenuated the effects of 0.2mg/mL APS on atrophy and autophagy.

CONCLUSIONS

Our results suggested APS could improve muscle wasting through Akt/mTOR, ubiquitin proteasome and autophagy signalling, and SLC38A2 may be one of potential targets.

Comparison of Intradialytic Parenteral Nutrition with Glucose or Amino Acid Mixtures in Maintenance Hemodialysis Patients

Many long-term maintenance hemodialysis patients have symptoms of protein-energy wasting caused by malnutrition. Each session of hemodialysis removes about 10 to 12 g of amino acids and 200 to 480 kcal of energy. Patients receiving hemodialysis for chronic kidney disease may be undernourished for energy, protein consumption, or both. Non-diabetic hemodialysis patients were randomized to three treatment groups: oral supplementation, oral supplementation plus high-concentration glucose solution (250 mL containing 50% glucose) and these two interventions plus 8.5% amino acids solution. The post-treatment energy status of the glucose group was significantly higher than its baseline level, whereas the control group’s status was significantly lower. The glucose group had significantly higher concentrations of asparagine, glutamine, glycine, alanine, and lysine after treatment. All treatment groups had significantly increased hemoglobin levels but significantly decreased transferrin levels after treatment compared to baseline. After treatment, the amino acid group had significantly higher albumin level compared to the glucose group (p = 0.001) and significantly higher prealbumin level compared to the control group (p = 0.017). In conclusion, long-term intervention with high-concentration glucose solution at each hemodialysis session is a simple and cheap method that replenished energy stores lost during hemodialysis of non-diabetic patients.

Dialysis modality and nutritional status are associated with variability of inflammatory markers

BACKGROUND

Inflammation is a common feature in dialysis patients and is associated with cardiovascular complications and poor outcome. Measuring the variability of inflammatory markers may help in understanding underlying factors triggering inflammation. Whether the inflammatory pattern in hemodialysis (HD) and peritoneal dialysis (PD) patients differs has scarcely been studied. Here we explored factors associated with the magnitude and variability of inflammation markers in HD and PD patients.

METHODS

In two 3-month, prospective cohort studies comprising 228 prevalent HD and 80 prevalent PD patients, interleukin-6 (IL-6) and high-sensitivity C-reactive protein (CRP) were measured in blood samples drawn each month and every week, respectively. Information on comorbidity, protein-energy wasting (PEW) and medications was gathered at baseline, and information on symptoms potentially related to inflammation was gathered weekly. A mixed-effect model was used for multivariate analysis of factors linked to CRP and IL-6 variation.

RESULTS

IL-6 and CRP levels were higher and showed higher variability in HD versus PD patients [median IL-6 8.3 (interquartile range, IQR, 5.3-14.5) versus 6.7 (IQR 4.2-10.0) pg/mL, P < 0.001 and median CRP 6.1 (IQR 2.5-14.0) versus 5.4 (IQR 1.6-9.0) mg/L, P < 0.001). PEW predicted increased inflammation variability after correcting for age, sex, dialysis vintage, modality and comorbidity. Increased comorbidity predicted IL-6, but not CRP, variability.

CONCLUSIONS

Circulating concentrations as well as variability of IL-6 and CRP levels were higher in HD as compared with PD patients. In HD and PD patients, short-term variability of IL-6 and CRP levels associated strongly with PEW, while comorbidity was related to IL-6 but not to CRP variability.

Hidden Obesity in Dialysis Patients: Clinical Implications

While body-mass index (BMI) is used to diagnose obesity in the general population, its application in the end-stage renal disease (ESRD) population is fraught with difficulty. A major limitation is its inability to distinguish muscle mass from fat mass, thereby leading to misclassification of individuals with poor muscle mass but excess adipose tissue as non-obese (i.e. BMI <30 kg/m(2) ). As muscle wasting is common among ESRD patients, this is an important problem. A substantial proportion of ESRD patients have levels of BMI in the normal range, yet excess adiposity based on other measures. The importance of this "hidden" obesity remains to be determined, but it must be recognized in order for obesity interventions to be appropriately targeted and tested in the ESRD population.

Sarcopenia and Physical Inactivity in Patients With Chronic Kidney Disease

Sarcopenia and physical inactivity synergistically progress in patients with chronic kidney disease (CKD) and are strong predictors of mortality in this population. Exercise training and essential amino acids and vitamin D supplements may contribute to improving sarcopenia and physical inactivity in CKD patients.

Validating Appetite Assessment Tools Among Patients Receiving Hemodialysis

OBJECTIVE

To test the performance of appetite assessment tools among patients receiving hemodialysis (HD).

DESIGN

Cross-sectional.

SUBJECTS

Two hundred twenty-one patients receiving HD enrolled in seven dialysis facilities in Northern California.

INTERVENTION

We assessed 5 appetite assessment tools (self-assessment of appetite, subjective assessment of appetite, visual analog scale [VAS], Functional Assessment of Anorexia/Cachexia Therapy [FAACT] score, and the Anorexia Questionnaire [AQ]).

MAIN OUTCOME MEASURES

Reported food intake, normalized protein catabolic rate, and change in body weight were used as criterion measures, and we assessed associations among the appetite tools and biomarkers associated with nutrition and inflammation. Patients were asked to report their appetite and the percentage of food eaten (from 0% to 100%) during the last meal compared to usual intake.

RESULTS

Fifty-eight (26%) patients reported food intake ≤ 50% (defined as poor appetite). The prevalence of anorexia was 12% by self-assessment of appetite, 6% by subjective assessment of appetite, 24% by VAS, 17% by FAACT score, and 12% by AQ. All the tools were significantly associated with food intake ≤ 50% (P < .001), except self-assessment of appetite. The FAACT score and the VAS had the strongest association with food intake ≤ 50% (C-statistic 0.80 and 0.76). Patients with food intake ≤ 50% reported weight loss more frequently than patients without low intake (36% vs 22%) and weight gain less frequently (19% vs 35%; P = .03). Normalized protein catabolic rate was lower among anorexic patients based on the VAS (1.1 ± 0.3 vs 1.2 ± 0.3, P = .03). Ln interleukin-6 correlated inversely with food intake (P = .03), but neither interleukin-6 nor C-reactive protein correlated with any of the appetite tools. Furthermore, only the self-assessment of appetite was significantly associated with serum albumin (P = .02), prealbumin (P = .02) and adiponectin concentrations (P = .03).

CONCLUSIONS

Alternative appetite assessment tools yielded widely different estimates of the prevalence of anorexia in HD. When considering self-reported food intake as the criterion standard for anorexia, the FAACT score and VAS discriminated patients reasonably well.

Relationship between the target dose for hemodialysis adequacy and nutritional assessment

BACKGROUND

Some studies have shown an increased relative risk of death for patients with higher levels of Kt/V, which may be associated with marked malnutrition.

OBJECTIVE

The aim of this study was to investigate the relationship between the target dose for hemodialysis adequacy, as measured by Kt/V, and various nutritional parameters in hemodialysis patients.

DESIGN

Cross-sectional.

SETTINGS

Sakarya University Faculty of Medicine, Turkey between February 2014 and March 2014.

PATIENTS AND METHODS

For consecutive patients who met criteria, the following were recorded: nutritional status, dialysis malnutrition score (DMS), the geriatric nutritional risk index (GNRI), serum albumin level, anthropometric measurements, and bioelectrical impedance analysis. Patients were classified into two groups according to the target hemodialysis dose for single-pool Kt/V: patients with spKt/V >=1.4 and patients with spKt/V < 1.4.

MAIN OUTCOME MEASURE(S)

Association of hemodialysis adequacy by nutritional assessment.

RESULTS

The prevalence of malnutrition in 286 patients with target dose hemodialysis (spKt/V >=1.4) was significantly higher according to body mass index (BMI), DMS, and GDRI (P=.001, P=.006, and P=.004, respectively) compared with patients with a lower target dose (spKt/V < 1.4). BMI, biceps skinfolds, mid-arm circumference, calf circumference, fat free mass, and total body water were statistically significantly lower in patients at a higher target dose (spKt/V >= 1.4) (P < .001, P=.034, P=.010, P < .001, P < .001, and P < .001 respectively).

CONCLUSIONS

Malnutrition was more frequent in chronic hemodialysis patients who received the target hemodialysis. Evaluation of nutritional status in patients at the target hemodialysis dose should be considered.

LIMITATIONS

Data collected from a single region; small sample size; cross-sectional design is disadvantageous.

Dietary Quality and Adherence to Dietary Recommendations in Patients Undergoing Hemodialysis

BACKGROUND

The multiple dietary restrictions recommended to hemodialysis patients may be difficult to achieve and, at the same time, may result in nutritional deficiencies rendering a poor dietary quality. We here assess the dietary quality and adherence to renal-specific guideline recommendations among hemodialysis patients from a single center in Canary Islands, Spain.

METHODS

Cross-sectional study, including 91 patients undergoing maintenance hemodialysis. Clinical data and 3-day dietary records were collected. We compared patient's reported nutrients intake with guideline recommendations. We also evaluated their alignment with current American Heart Association dietary guidelines for cardiovascular prevention.

RESULTS

Seventy-seven percent and 50% of patients consumed less than the recommended daily energy and protein, respectively. Although half of the patients met the recommendations for dietary fat intake, this was accounted by an excess of saturated fat in 92% of them. Only 22% consumed sufficient fiber. A very small proportion of patients (less than 50%) met the requirements for vitamins and other micronutrients. Insufficient dietary intake was observed in most patients for all vitamins except for cobalamin. Similarly, inadequate dietary intake was observed for many minerals, by both excess (phosphorus, calcium, sodium, and potassium) and defect (magnesium). Most patients met the recommendations for iron and zinc in their diets.

CONCLUSIONS

A large proportion of hemodialysis patients at our center did not meet current renal-specific dietary recommendations. The quality of the diet was considered poor and proatherogenic according to American Heart Association guidelines.

Therapeutics targeting persistent inflammation in chronic kidney disease

Systemic inflammation is a condition intrinsically linked to chronic kidney disease (CKD) and its other typical sequelae, such as acquired immune dysfunction, protein-energy wasting (PEW), and accelerated vascular aging that promote premature cardiovascular disease (CVD) and infections, the two leading causes of death in CKD patients. Inflammation is a major contributor to complications in CKD, and inflammatory markers, such as C-reactive protein and pro- and anti-inflammatory cytokines, correlate with underlying causes and consequences of the inflamed uremic phenotype, such as oxidative stress, endothelial dysfunction, CVD, PEW, and infections, and are sensitive and independent predictors of outcome in CKD. Therefore, inflammation appears to be a logical target for potential preventive and therapeutic interventions in patients with CKD. Putative anti-inflammatory therapy strategies aiming at preventing complications and improving outcomes in CKD span over several areas: (1) dealing with the source of inflammation (such as cardiovascular, gastrointestinal or periodontal disease and depression); (2) providing nonspecific immune modulatory effects by promoting healthy dietary habits and other lifestyle changes; (3) promoting increased use of recognized pharmacologic interventions that have pleiotropic effects; and, (4) introducing novel targeted anticytokine interventions. This review provides a brief update on inflammatory biomarkers and possible therapeutic approaches targeting inflammation and the uremic inflammatory milieu in patients with CKD.

The Associations of Plant Protein Intake With All-Cause Mortality in CKD

BACKGROUND

Plant protein intake is associated with lower production of uremic toxins and lower serum phosphorus levels. Therefore, at a given total protein intake, a higher proportion of dietary protein from plant sources might be associated with lower mortality in chronic kidney disease.

STUDY DESIGN

Observational study.

SETTINGS & PARTICIPANTS

14,866 NHANES III participants 20 years or older without missing data for plant and animal protein intake and mortality.

PREDICTORS

Plant protein to total protein ratio and total plant protein intake. Patients were stratified by estimated glomerular filtration rate (eGFR)<60 or ≥60mL/min/1.73m(2).

OUTCOMES

All-cause mortality.

MEASUREMENTS

Plant and total protein intakes were estimated from 24-hour dietary recalls. Mortality was ascertained by probabilistic linkage with National Death Index records through December 31, 2000.

RESULTS

Mean values for plant protein intake and plant protein to total protein ratio were 24.6±13.2 (SD) g/d and 33.0% ± 14.0%, respectively. The prevalence of eGFRs<60mL/min/1.73m(2) was 4.9%. There were 2,163 deaths over an average follow-up of 8.4 years. Adjusted for demographics, smoking, alcohol use, comorbid conditions, body mass index, calorie and total protein intake, and physical inactivity, each 33% increase in plant protein to total protein ratio was not associated with mortality (HR, 0.88; 95% CI, 0.74-1.04) in the eGFR≥60mL/min/1.73m(2) subpopulation, but was associated with lower mortality risk (HR, 0.77; 95% CI, 0.61-0.96) in the eGFR<60mL/min/1.73m(2) subpopulation. In sensitivity analyses, results were similar in those with eGFR<60mL/min/1.73m(2) defined by serum cystatin C level.

LIMITATIONS

Whether results are related to plant protein itself or to other factors associated with more plant-based diets is difficult to establish.

CONCLUSIONS

A diet with a higher proportion of protein from plant sources is associated with lower mortality in those with eGFR<60mL/min/1.73m(2). Future studies are warranted to determine the causal role of plant protein intake in reducing mortality in those with eGFR<60mL/min/1.73m(2).

[Sarcopenia or uremic myopathy in CKD patients]

Often underestimated or misunderstood in chronic renal failure (CRF), muscle wasting is nevertheless common and concerns about 50% of dialysis patients. The consequences of this myopathy on quality of life and outcomes of patients are unfavorable, identical to those observed in sarcopenia in elderly subjects with sarcopenia. The similarities between the two situations also concern the symptoms, the underlying muscle damages and the pathogenic mechanisms and may be partly explained by the frequently high age of ESRD patients. Skeletal muscle involvement should be systematically investigated in the IRC patient as in the elderly with sarcopenia to propose as early as possible a treatment of which physical activity and nutritional interventions are the mainstay.

A cohort study of insulin-like growth factor 1 and mortality in haemodialysis patients

Background

Protein-energy wasting (PEW) is highly prevalent in haemodialysis (HD) patients and associated with increased mortality and cardiovascular disease (CVD). Insulin-like growth factor 1 (IGF-1) correlates to markers of PEW and CVD. Disturbances in the growth hormone axis in end-stage renal disease (ESRD) could have an impact on survival through increased PEW and CVD.

Methods

A cohort of 265 incident HD patients (median age 68 years, 59% males) was followed for 3 years. Subjects were categorized according to IGF-1 levels at dialysis initiation. Outcome and comorbidity data were retrieved from national registers. The Kaplan–Meier diagram and Cox proportional hazards model were used for the analysis of survival.

Results

Patients with IGF-1 levels in the lowest tertile were characterized by female sex, low creatinine, hypoalbuminemia and high C-reactive protein (CRP) levels. IGF-1 levels within the lowest tertile were associated with increased mortality [hazard ratio (HR) 2.4, 95% confidence interval (CI) 1.7–3.4]. This association persisted when corrected for demographic factors (age, sex) and comorbidities (diabetes mellitus, CVD, heart failure) in multivariable analysis. Including high-sensitivity C-reactive protein (hs-CRP) and serum creatinine in the model had a small effect on the magnitude of the hazard. When serum albumin was added to the model, the HR declined from 2.2 to 1.6, but remained significant (P = 0.02).

Conclusion

Low IGF-1 levels associate with increased mortality in HD, independent of biomarkers of inflammation (hs-CRP) and PEW (creatinine, albumin). Serum albumin modulates the relationship between IGF-1 levels and mortality, indicating shared pathophysiological pathways with IGF-1.

[The Experience of Fluid Management in Hemodialysis Patients]

PURPOSE

The purpose of this study was to explore the experience of fluid management in hemodialysis patients by describing how they manage fluid intake and what affects fluid management.

METHODS

Purposive sampling yielded 11 patients who have received hemodialysis for one year or longer in one general hospital. Data were collected through in-depth interviews and analysed using Giorgi's phenomenological method. Data collection and analysis were performed concurrently.

RESULTS

The findings regarding how hemodialysis patients manage fluid intake were classified into four constituents: 'recognizing the need for fluid control', 'observing the status of fluid accumulation', 'controlling fluid intake and output', 'getting used to fluid management'. The factors that affect fluid management of hemodialysis patients were revealed as 'willpower', 'change in the mindset', 'support system', and 'emotional state'.

CONCLUSION

The study results show that hemodialysis patients manage fluid intake through food and exercise as well as interpersonal relationships. These findings suggest that strategies in the development of nursing interventions for hemodialysis patients should be directed at assisting them in familiarization with fluid management based on an understanding of their sociocultural contexts.

Examining the robustness of the obesity paradox in maintenance hemodialysis patients: a marginal structural model analysis

BACKGROUND

The inverse association between body mass index (BMI) and mortality observed in patients treated with maintenance hemodialysis (MHD), also known as the obesity paradox, may be a result of residual confounding. Marginal structural model (MSM) analysis, a technique that accounts for time-varying confounders, may be more appropriate to investigate this association. We hypothesize that after applying MSM, the inverse association between BMI and mortality in MHD patients is attenuated.

METHODS

We examined the associations between BMI and all-cause mortality among 123 624 adult MHD patients treated during 2001-6. We examined baseline and time-varying BMI using Cox proportional hazards models and MSM while considering baseline and time-varying covariates, including demographics, comorbidities and markers of malnutrition and inflammation.

RESULTS

The patients included 45% women and 32% African Americans with a mean age of 61(SD 15) years. In all models, BMI showed a linear incremental inverse association with mortality. Compared with the reference (BMI 25 to <27.5 kg/m(2)), a BMI of <18 kg/m(2) was associated with a 3.2-fold higher death risk [hazard ratio (HR) 3.17 (95% CI 3.05-3.29)], and mortality risks declined with increasing BMI with the greatest survival advantage of 31% lower risk [HR 0.69 (95% CI 0.64-0.75)] observed with a BMI of 40 to <45 kg/m(2).

CONCLUSIONS

The linear inverse relationship between BMI and mortality is robust across models including MSM analyses that more completely account for time-varying confounders and biases.

Hypoalbuminaemia in haemodialysis patients at Parirenyatwa group of hospitals and Chitungwiza central hospital

Introduction

Haemodialysis is one of the widely used methods in end stage renal disease. However it has a negative impact on the quality of life of the renal patients. Hypoalbuminaemia occur in haemodialysis patients and it correlates strongly with mortality and morbidity. We sought out to determine the prevalence of hypoalbuminaemia among haemodialysis patients at Parirenyatwa group of hospitals and Chitungwiza central hospital.

Methods

A questionnaire was administered on haemodialysis patients at Parirenyatwa Group of Hospitals and Chitungwiza Central Hospital who consented to participate in the study. Pre dialysis serum samples collected from the patients were used for albumin analysis. The serum from the patients was analysed for serum albumin levels using the Mindray BS120 chemistry analyser using the bromocresol green method.

Results

A total of 60 patients were recruited from the two hospitals. The Mean albumin concentration for the entire group was 33.6g/L SD (6.1 g/L). The mean albumin in males was 33.6 g/L, SD (5.9) and in female 33.6, SD (6.6 g/L) and this was not statistically significantly different (p = 0.988). The prevalence of hypoalbuminaemia was 76.7%.

Conclusion

Hypoalbuminaemia in 76.7% of haemodialysis patients studied is a cause of concern thus monitoring of haemodialysis patients albumin is necessary since its decreased levels has been associated with increased morbidity and mortality.

Ratio of Dietary n-6/n-3 Polyunsaturated Fatty Acids Independently Related to Muscle Mass Decline in Hemodialysis Patients

Background

n-3 polyunsaturated fatty acids (PUFAs) might be useful nutritional strategy for treating patients with sarcopenia. We evaluated the effect of the intake of dietary n-3 PUFAs on the skeletal muscle mass (SMM), appendicular skeletal muscle mass (ASM), and its determinants in patients receiving standard hemodialysis (HD) treatment for the management of end stage renal disease.

Methods

In this cross-sectional study, data of 111 HD patients were analyzed. Anthropometric and bioelectrical impedance measurements used to estimate the muscle mass were performed the day of dialysis immediately after the dialysis session. Routine laboratory and 3-day dietary data were also collected. The cutoff value of adequate intake (AI) for both n-3 PUFAs and alpha-linolenic acid (ALA) was 1.6 g/day and 1.1 g/day for men and women, respectively.

Results

The mean age, mean dietary n-3 PUFAs intake, ALA intake, ratio of n-6/n-3 PUFAs intake, SMM, and ASM of patients were 61.4 ± 10.4 years, 2.0 ± 1.3 g/day, 1.5 ± 1.0 g/day, 9.5 ± 6.7 g/day, 23.9 ± 5.5 kg, and 17.5 ± 4.5 kg, respectively. A higher SMM and ASM significantly observed in patients who achieved an AI of n-3 PUFAs. Similar trends appeared to be observed among those patients who achieved the AI of ALA, but the difference was not significantly, except for ASM (P = 0.047). No relevant differences in demographics, laboratory and nutritional parameters were observed, regardless of whether the patients achieved an AI of n-3 PUFAs. Multivariate analysis showed that the BMI and equilibrated Kt/V were independent determinants of the muscle mass. Moreover, the ratio of n-6/n-3 PUFAs was an independent risk determinant of reduced ASM in HD patients.

Conclusion

Patients with an AI of n-3 PUFAs had better total-body SMM and ASM. A higher dietary ratio of n-6/n-3 PUFAs seemed to be associated with a reduced muscle mass in HD patients.

Effect of a low-protein diet supplemented with keto-acids on autophagy and inflammation in 5/6 nephrectomized rats

The present study demonstrated that autophagy/mitophagy was increased and inflammation was aggravated in skeletal muscle in chronic kidney disease (CKD) rats. A low-protein diet (LPD) supplemented with ketoacids (KA) improved the loss in muscle mass and blocked the activation of autophagy/mitophagy and inflammation in those rats.

Ketoacids (KA) are known to preserve muscle mass among patients with chronic kidney disease (CKD) on a low-protein diet (LPD). The present study was to compare the effects of KA supplemented diet therapy in autophagy and inflammation in CKD rats' skeletal muscle. Rats with 5/6 nephrectomy were randomly divided into three groups and fed with either 11 g/kg/day protein [normal-protein diet (NPD)], 3 g/kg/day protein (LPD) or 3 g/kg/day protein which including 5% protein plus 1% KA (LPD + KA) for 24 weeks. Sham-operated rats with NPD intake were used as control. LPD could improve body weight, gastrocnemius muscle mass, as well as gastrocnemius muscle cross-sectional area, with the effect being more obvious in the LPD + KA group. The autophagy marker LC3 (microtubule-associated protein 1 light chain 3), p62, Parkin and PTEN induced putative kinase 1 (PINK1) were significantly attenuate in LPD + KA group than LPD group. LPD + KA group had the lower total mtDNA (mitochondiral DNA) and cytosol mtDNA, NACHT-PYD-containing protein 3 (NALP3) inflammasome than LPD group, but its reactive oxygen species (ROS), caspase-1 and apoptosis-associated speck-like protein containing a CARD (ASC) level was higher. Immunoblotting showed IL-1β (interleukin-1-beta) was lower in LPD and LPD + KA group than the NPD group, but IL-18 showed no significant difference among control and CKD group; toll-like receptor signalling-dependent IL-6 was higher in LPD + KA group than LPD group, but tumor necrosis factor-α (TNF-α) was not significantly changed between LPD + KA and LPD group. Systematic changes of the four cytokines were different from that of the tissue. Although LPD + KA could further ameliorate-activated autophagy than LPD, its effect on the activated inflammation state in CKD was not distinctly. Further study is still required to explore the method of ameliorating inflammation to provide new therapeutic approaches for CKD protein energy wasting (PEW).

C-reactive Protein: Repeated Measurements will Improve Dialysis Patient Care

Systemic inflammation is a common feature in the uremic phenotype and associates with poor outcomes. The awareness regarding the importance of inflammation assessment in chronic kidney disease (CKD) patients has risen in recent years, and despite the development of novel biomarkers, C-reactive protein (CRP) is still the most measured inflammatory parameter. Notwithstanding, the possible weak points of CRP determination, this biomarker has demonstrated being useful both for guidance in clinical practice and for risk estimation. In addition, regular determination of CRP among dialysis patients has been associated with better outcomes in different dialysis facilities. Because persistent inflammation may be a silent reflection of various pathophysiologic alterations in CKD, it is crucial that inflammatory markers are regularly monitored and therapeutic attempts be made to target this inflammation.

Assessing protein energy wasting in a Malaysian haemodialysis population using self-reported appetite rating: a cross-sectional study

BACKGROUND

Poor appetite could be indicative of protein energy wasting (PEW) and experts recommend assessing appetite in dialysis patients. Our study aims to determine the relationship between PEW and appetite in haemodialysis (HD) patients.

METHODS

HD patients (n=205) self-rated their appetite on a scale of 1 to 5 as very good (1), good (2), fair (3), poor (4) or very poor (5). Nutritional markers were compared against appetite ratings. Using logistic regression analysis associations between dichotomized appetite with PEW diagnosis were determined as per the International Society of Renal Nutrition and Metabolism (ISRNM) criteria and alternate objective measures. Data was adjusted for socioeconomic and demographic characteristics.

RESULTS

Poorer appetite ratings were significantly associated with lower income (P = 0.021), lower measurements (P < 0.05) for mid-arm muscle circumference, mid-arm muscle area and lean tissue mass (LTM), serum urea (P = 0.007) and creatinine (P = 0.005). The highest hsCRP (P = 0.016) levels occurred in patients reporting the poorest appetite. Serum albumin did not differ significantly across appetite ratings. Poor oral intake represented by underreporting (EI/BMR < 1.2) was evident for all appetite ratings. PEW was prevalent irrespective of appetite ratings (very good: 17.6 %, good: 40.2 %, fair: 42.3 % and poor: 83.3 %). After dichotomizing appetite ratings into normal and diminished categories, there was a marginal positive association between diminished appetite and overall PEW diagnosis (OR adj: 1.71; 95 % CI: 0.94-3.10, P = 0.079). Amongst individual ISRNM criteria, only BMI < 23 kg/m2 was positively associated with diminished appetite (OR adj: 2.17; 95 % CI: 1.18-3.99). However, patients reporting diminished appetite were more likely to have lower LTM (OR adj: 2.86; 95 % CI: 1.31-6.24) and fat mass (OR adj: 1.91; 95 % CI: 1.03-3.53), lower levels of serum urea (OR adj: 2.74; 95 % CI: 1.49-5.06) and creatinine (OR adj: 1.99; 95 % CI: 1.01-3.92), higher Dialysis Malnutrition Score (OR adj: 2.75; 95 % CI: 1.50-5.03), Malnutrition Inflammation Score (OR adj: 2.15; 95 % CI: 1.17-3.94), and poorer physical (OR adj: 3.49; 95 % CI: 1.89-6.47) and mental (OR adj: 5.75; 95 % CI: 3.02-10.95) scores.

CONCLUSIONS

A graded but non-significant increase in the proportion of PEW patients occurred as appetite became poorer. However, after dichotomization, a positive but marginally significant association was observed between diminished appetite and PEW diagnosis.

Relationship between Stage of Chronic Kidney Disease and Sarcopenia in Korean Aged 40 Years and Older Using the Korea National Health and Nutrition Examination Surveys (KNHANES IV-2, 3, and V-1, 2), 2008-2011

Background

Protein-energy wasting is common in patients with end-stage kidney disease. However, few studies have examined the relationship between early stages of chronic kidney disease (CKD) and sarcopenia.

Methods

We conducted a cross-sectional study based on data in the Korea National Health and Nutrition Examination Survey, 2008–2011. In total, 11,625 subjects aged 40 years or older who underwent dual-energy X-ray absorptiometry were analyzed. Sarcopenia was defined based on values of appendicular skeletal muscle mass as a percentage of body weight (ASM/Wt) two standard deviations below the gender-specific mean for young adults. Estimated glomerular filtration rates (eGFR) were calculated using the CKD-EPI equation.

Results

Mean age, body mass index (BMI), and HOMA-IR were higher and caloric intake, physical activity, and vitamin D level were lower in the sarcopenia groups in both men and women. As the stage of CKD increased, the prevalence of sarcopenia increased, even in the early stages of CKD (normal and CKD1, 2, and 3-5: 2.6%, 5.6%, and 18.1% in men and 5.3%, 7.1%, and 12.6% in women, respectively; p < 0.001). In addition, a correlation analysis showed that GFR and ASM/Wt had significant correlations in both men and women. Logistic regression analyses, after adjusting for age, BMI, caloric intake, log(physical activity), vitamin D level, and log(HOMA-IR), showed that the odds ratio for sarcopenia with respect to CKD 3–5 was 1.93 (95% CI = 1.02–3.68) in men but was not statistically significant in women.

Conclusions

The prevalence of sarcopenia was higher in elderly Korean patients with even mildly reduced kidney function. Stage of CKD was associated with an increased prevalence of sarcopenia in men but not women. Thus, we should evaluate the risk of sarcopenia and work to prevent it, even in patients with early CKD.

Indoxyl sulfate suppresses hepatic fetuin-A expression via the aryl hydrocarbon receptor in HepG2 cells

BACKGROUND

Fetuin-A is a liver-derived circulating protein that has potent calcification-inhibitory activity. Uraemic patients exhibit decreased serum fetuin-A levels, increased vascular calcification and elevated cardiovascular mortality. Because the mechanisms for fetuin-A deficiency are unknown, we hypothesized that some uraemic toxins suppressed hepatic fetuin-A production, which resulted in accelerated vascular calcification and poor outcome. Among these potential candidates, indoxyl sulfate (IS) has highly toxic properties.

METHODS

We examined the direct effects of IS on hepatic fetuin-A expression using the human hepatoma HepG2 cell line.

RESULTS

IS, but not p-cresyl sulfate, suppressed the mRNA and protein expression of fetuin-A in a dose- and time-dependent manner. As reported previously, IS stimulated p38 MAPK phosphorylation and reactive oxygen species (ROS) production, although the knockdown of p38 and inhibition of ROS generation had no effect on IS-induced fetuin-A suppression. Then, because IS is a potent endogenous ligand of the aryl hydrocarbon receptor (AhR), we assessed whether IS suppresses fetuin-A production via AhR. The knockdown of AhR prevented IS-induced fetuin-A suppression. However, some attention should be paid to no effect of IS on fetuin-A expression in mouse and human primary cultured hepatocytes.

CONCLUSIONS

These findings suggest that IS could suppress hepatic fetuin-A expression by activating AhR, suggesting a relationship between uraemia and fetuin-A deficiency.

Taste genetics and gastrointestinal symptoms experienced in chronic kidney disease

BACKGROUND/OBJECTIVES

It is unknown what causes uraemic symptoms in renal disease. Chronic kidney disease (CKD) patients are known to have increased levels of urea, sodium, potassium and phosphate in their saliva compared with those without renal disease. The present cross-sectional study investigated associations between known genetic traits of taste and self-reported upper gastrointestinal (GI) symptoms experienced in CKD patients with the changes in saliva composition found in renal failure.

SUBJECTS/METHODS

Fifty-six CKD patients (35 males, 21 females, age 67±14 years), with stages 4 and 5 renal failure, selected from a tertiary hospital renal outpatient clinic participated in this study. Subjects answered a questionnaire to assess upper GI symptoms and tested for the genetic taste recognition thresholds of thiourea, phenylthiocarbamide and sodium benzoate. Saliva samples were collected to determine biochemical composition. Possible associations between genetic taste variations, saliva composition and upper GI symptoms were investigated.

RESULTS

Of the 56 patients enroled, 29 (52%) reported major upper GI uraemic symptoms, whereas 27 (48%) had no symptoms or only minor complaints of dry mouth. There was a strong association between the symptomatic burden a patient experienced and the genetic ability to taste thiourea (P<0.0003). Uraemic symptoms of taste changes (P<0.004) and nausea (P<0.002) were found to be related to a patient's genetic ability to taste thiourea.

CONCLUSIONS

This study provides evidence that the genetic ability to taste thiourea as bitter, in combination with the increase in active compounds found in CKD patient's saliva, impacts on the uraemic upper GI symptoms experienced.

Evaluation of Nutritional Biochemical Parameters in Haemodialysis Patients over a Ten-year Period

AIM

Protein-energy malnutrition as well as systemic inflammation and metabolic disorders are common in patients with chronic kidney failure, who require renal replacement therapy (haemodialysis). Such malnutrition is a factor that significantly contributes to their morbidity and mortality. This study evaluated the nutritional status of haemodialysis patients by assessing biochemical and anthropometric parameters in order to determine whether these patients suffered disorders reflecting nutritional deterioration directly related to time on haemodialysis.

SUBJECTS AND METHOD

This research comprised 90 patients of both genders with chronic kidney failure, who regularly received haemodialysis at our unit over a period of ten years. The patients' blood was tested quarterly for plasma albumin, total cholesterol and total proteins, and tested monthly for transferrin. The patients' weight, height and body mass index (BMI) were monitored. Body mass index was calculated using the formula: weight (kg)/height (m2 ) and classified in one of the following categories defined in the World Health Organization (WHO) Global Database on Body Mass Index: (i) underweight [BMI < 18.50], (ii) normal [BMI 18.50 - 24.99], (iii) overweight [BMI 25 - 29.99], (iv) obese [BMI > 30].

RESULTS

In the ten-year period of the study, the patients experienced a substantial decline in their biochemical parameters. Nevertheless, their BMI did not show any significant changes despite the patients' state of malnutrition.

CONCLUSIONS

The prevalence of malnutrition in haemodialysis patients was evident. Nevertheless, the BMI of the subjects did not correspond to the biochemical parameters measured. Consequently, the results showed that the nutritional deterioration of these patients was mainly reflected in their biochemical parameters rather than in their anthropometric measurements.