POOR NUTRITIONAL STATUS AND INFLAMMATION: Novel Approaches in an Integrated Therapy of Inflammatory-Associated Wasting in End-Stage Renal Disease

Development and external validation of a perioperative clinical model for predicting myocardial injury after major abdominal surgery: A retrospective cohort study

Purpose

We aimed to develop and validate a predictive model for myocardial injury in individuals undergoing major abdominal surgery.

Methods

This multicenter retrospective cohort analysis included 3546 patients aged ≥45 years who underwent major abdominal surgeries at two Chinese tertiary hospitals. The primary outcome was myocardial injury after noncardiac surgery (MINS), defined as prognostically relevant myocardial injury due to ischemia that occurs during or within 30 days after noncardiac surgery. The LASSO algorithm and logistic regression were used to construct a predictive model for postoperative MINS in the development cohort, and the performance of this prediction model was validated in an external independent cohort.

Results

A total of 3546 patients were included in our study. MINS manifested in 338 (9.53 %) patients after surgery. The definitive predictive model for MINS was developed by incorporating age, American Society of Anesthesiologists (ASA) classification, preoperative hemoglobin concentration, preoperative serum ALB concentration, blood loss, total infusion volume, and operation time. The area under the curve (AUC) of our model was 0.838 and 0.821 in the derivation and validation cohorts, respectively.

Conclusions

Preoperative hemoglobin levels, preoperative serum ALB concentrations, infusion volume, and blood loss are independent predictors of MINS. Our predictive model can prove valuable in identifying patients at moderate-to-high risk prior to non-cardiac surgery.

Skeletal Muscle Injury in Chronic Kidney Disease-From Histologic Changes to Molecular Mechanisms and to Novel Therapies

Chronic kidney disease (CKD) is associated with significant reductions in lean body mass and in the mass of various tissues, including skeletal muscle, which causes fatigue and contributes to high mortality rates. In CKD, the cellular protein turnover is imbalanced, with protein degradation outweighing protein synthesis, leading to a loss of protein and cell mass, which impairs tissue function. As CKD itself, skeletal muscle wasting, or sarcopenia, can have various origins and causes, and both CKD and sarcopenia share common risk factors, such as diabetes, obesity, and age. While these pathologies together with reduced physical performance and malnutrition contribute to muscle loss, they cannot explain all features of CKD-associated sarcopenia. Metabolic acidosis, systemic inflammation, insulin resistance and the accumulation of uremic toxins have been identified as additional factors that occur in CKD and that can contribute to sarcopenia. Here, we discuss the elevation of systemic phosphate levels, also called hyperphosphatemia, and the imbalance in the endocrine regulators of phosphate metabolism as another CKD-associated pathology that can directly and indirectly harm skeletal muscle tissue. To identify causes, affected cell types, and the mechanisms of sarcopenia and thereby novel targets for therapeutic interventions, it is important to first characterize the precise pathologic changes on molecular, cellular, and histologic levels, and to do so in CKD patients as well as in animal models of CKD, which we describe here in detail. We also discuss the currently known pathomechanisms and therapeutic approaches of CKD-associated sarcopenia, as well as the effects of hyperphosphatemia and the novel drug targets it could provide to protect skeletal muscle in CKD.

Dietary Patterns and Perceptions in Older Adults With Chronic Kidney Disease in the Canadian Frailty Observation and Interventions Trial (CanFIT): A Mixed-Methods Study

Background:

People living with chronic kidney disease (CKD) have identified diet as an important aspect of their life and care. Understanding current consumption patterns in this population, and how they relate to patient perspectives of dietary recommendations, may help identify and design potential dietary intervention strategies in CKD.

Objective:

To investigate the dietary intake patterns of people with advanced-stage CKD, as well as subjective perspectives regarding dietary recommendations from participants and their caregivers.

Design:

Mixed-methods study with a sequential explanatory design.

Setting:

Manitoba, Canada.

Participants:

Individuals with late-stage CKD (CKD stages G4-G5, including dialysis) participating in the Canadian Frailty Observation and Interventions Trial (CanFIT).

Methods:

First, quantitative data were collected via a cross-sectional dietary assessment, using three 24-hour dietary recalls, a 36-question short diet questionnaire (SDQ), and a Nutrition Quality of Life (NQoL) tool (n = 59). Second, qualitative data were collected during 2 focus groups (n₁ = 12 and n₂ = 7) held with a subsample of individuals who had completed the dietary surveys, along with their caregivers. Focus groups explored topics related to diet and CKD; transcribed data were analyzed thematically. In the interpretation stage, the qualitative findings were combined with the quantitative results to help explain the latter and reach a deeper understanding of the subjective experiences of adults with CKD.

Results:

Quantitatively, nearly all (48/51; 94%) participants (mean age 70.8 ± 10.8 years) reported energy intakes below recommendations and most (86%) did not achieve recommended fiber intake. In addition, 15/21 (71%) of patients on dialysis had low protein intake. Qualitatively, 2 themes were identified: (1) Lacking/Needing dietary guidance—incomplete “information overload,” and (2) Experiencing difficulty in adapting to restrictions. Within the former theme, participants spoke of getting too much information at once, often at the wrong time. Within the latter theme, participants spoke of a loss of appetite, and cheating on their dietary recommendations.

Limitations:

Potential recall bias recalling dietary patterns, small sample size limiting generalizability, self-selection bias.

Conclusion:

Despite the reported lifestyle changes made by individuals with CKD, which negatively impacted their lives, many had suboptimal nutrition, especially in terms of energy and fiber. In addition, those on dialysis were not eating enough protein, which could be due to changing dietary recommendations as CKD progresses. Qualitative findings provided additional insight into how requisite CKD-dietary changes were perceived and how participants coped with these changes. The timing and delivery of the dietary education within CKD care in Manitoba may not be working for people with CKD as they progress through the disease.

Impact of Cafeteria Service Discontinuation at a Dialysis Facility on Medium-Term Nutritional Status of Elderly Patients Undergoing Hemodialysis

Despite evident lifestyle changes due to measures against the coronavirus disease 2019 (COVID-19) outbreak, few reports focus on the effects of eating-behavior changes on the nutritional status of elderly patients undergoing hemodialysis (HD). Thus, we examined dry-weight reduction, the simplest indicator of malnutrition among patients undergoing dialysis, and its association with the discontinuation of cafeteria services at a dialysis facility as per COVID-19 measures. This retrospective study included elderly patients (aged ≥ 65 years) undergoing HD at the Nagasaki Renal Center between December 2020 and October 2021. We collected nutrition-related data and patient characteristics and evaluated the association between the service discontinuation and dry-weight reduction 10 months after the discontinuation using multivariable logistic regression. This study included 204 patients, 79 of which were cafeteria users. During the observation period, cafeteria users showed significant dry-weight reduction; however, this was not observed among non-users. Multivariable logistic regression analysis indicated a close association between dry-weight reduction and the service discontinuation. That is, the dietary services cancelation caused dry-weight reduction in patients who relied on the cafeteria. As elderly patients undergoing HD are vulnerable to changes in their eating environment, alternative nutritional management methods need to be considered.

Muscle-Bone Crosstalk in Chronic Kidney Disease: The Potential Modulatory Effects of Exercise

Chronic kidney disease (CKD) is a prevalent worldwide public burden that increasingly compromises overall health as the disease progresses. Two of the most negatively affected tissues are bone and skeletal muscle, with CKD negatively impacting their structure, function and activity, impairing the quality of life of these patients and contributing to morbidity and mortality. Whereas skeletal health in this population has conventionally been associated with bone and mineral disorders, sarcopenia has been observed to impact skeletal muscle health in CKD. Indeed, bone and muscle tissues are linked anatomically and physiologically, and together regulate functional and metabolic mechanisms. With the initial crosstalk between the skeleton and muscle proposed to explain bone formation through muscle contraction, it is now understood that this communication occurs through the interaction of myokines and osteokines, with the skeletal muscle secretome playing a pivotal role in the regulation of bone activity. Regular exercise has been reported to be beneficial to overall health. Also, the positive regulatory effect that exercise has been proposed to have on bone and muscle anatomical, functional, and metabolic activity has led to the proposal of regular physical exercise as a therapeutic strategy for muscle and bone-related disorders. The detection of bone- and muscle-derived cytokine secretion following physical exercise has strengthened the idea of a cross communication between these organs. Hence, this review presents an overview of the impact of CKD in bone and skeletal muscle, and narrates how these tissues intrinsically communicate with each other, with focus on the potential effect of exercise in the modulation of this intercommunication.

Identifying and Managing Malnutrition Stemming from Different Causes

Protein–energy malnutrition (PEM) is highly prevalent among peritoneal dialysis (PD) patients and is a strong predictor of morbidity and mortality. A wide range of factors can lead to PEM and associated wasting (PEM/W) in PD patients, but persistent inflammation and the presence of diabetes have been identified as the two main reasons. An important body of literature has been reporting studies of methods suitable for detecting malnutrition in its early phase so that appropriate intervention can be provided. Although assessment of nutrition status has been substantially improved, no definitive single method of assessing nutrition status has been decided. Rather, several different markers of nutrition should be evaluated together. Because of the complexity of treating malnutrition in PD patients, nontraditional strategies such as appetite stimulants, anti-inflammatory diets, and anti-inflammatory pharmacologic agents are recommended to be combined with more traditional forms of nutritional support, so as to provide a better chance of recovery. The present review briefly discusses the causes of PEM/W, the methods most commonly used to identify the condition, and the new management strategies available.

Ultrasound assessment of muscle mass in response to exercise training in chronic kidney disease: a comparison with MRI

BACKGROUND

Chronic kidney disease (CKD) is a catabolic condition associated with muscle wasting and dysfunction, which associates with morbidity and mortality. There is a need for simple techniques capable of monitoring changes in muscle size with disease progression and in response to interventions aiming to increase muscle mass and function. Ultrasound is one such technique; however, it is unknown how well changes in muscle cross-sectional area (CSA) measured using ultrasound relate to changes in whole muscle volume measured using magnetic resonance imaging. We tested whether rectus femoris CSA (RF-CSA) could be used as a valid indication of changes in quadriceps muscle volume as a single measure of muscle size and following a 12 week exercise intervention that resulted in muscle hypertrophy.

METHODS

Secondary analysis of data was collected from the ExTra CKD study (ISRCTN 36489137). Quadriceps muscle size was assessed from 36 patients with non-dialysis CKD before and after 12 weeks of supervised exercise that resulted in muscle hypertrophy.

RESULTS

Strong positive correlations were observed between RF-CSA and quadriceps volume at baseline (r² = 0.815, CI 0.661 to 0.903; P < 0.001) and following 12 week exercise (r² = 0.845, CI 0.700 to 0.923; P < 0.001). A moderate positive association was also observed between changes in RF-CSA and quadriceps following exercise training (rho = 0.441, CI 0.085 to 0.697; P = 0.015). Bland-Altman analysis revealed a small bias (bias 0.6% ± 12.5) between the mean percentage changes in RF-CSA and quadriceps volume but wide limits of agreement from -24 to 25.

CONCLUSIONS

Rectus femoris CSA appears to be a reliable index of total quadriceps volume as a simple measure of muscle size, both as a single observation and in response to exercise training in non-dialysis CKD patients.

Plasma gelsolin level predicts acute kidney injury after cardiopulmonary bypass in infants and young children

BACKGROUND

Acute kidney injury (AKI) after cardiopulmonary bypass (CPB) is a common complication especially in pediatric population. Plasma gelsolin (pGSN) is an anti-inflammatory factor through binding with actin and pro-inflammatory cytokines in circulation. Decrease in pGSN has been reported in some pathologic conditions. The purpose of the study was to determine the alterations of pGSN level in infants and young children after CPB and the role of pGSN as a predictor for the morbidity and severity of post-CPB AKI.

METHODS

Sixty-seven infants and young children at age ≤ 3 years old undergoing CPB were prospectively enrolled. PGSN levels were measured during peri-operative period with enzyme-linked immuno-sorbent assay and normalized with plasma total protein concentration. Other clinical characteristics of the patients were also recorded.

RESULTS

In patients developing AKI, the normalized pGSN (pGSN_N) levels significantly decreased at 6 h post-operation and remained low for 24 h post-operation as compared to the patients with non-AKI. PGSN_N at 6 h post-operation combining with CPB time presents an excellent predictive value for AKI.

CONCLUSIONS

Decreased pGSN_N identifies post-CPB AKI in the patients ≤ 3 years old, and is associated with adverse clinical outcomes. The findings suggest that circulating GSN in post-CPB patients may have beneficial effects on diminishing inflammatory responses.

Malnutrition, inflamation and atherosclerosis (MIA syndrome) in patients with end stage renal disease on maintenance hemodialysis (a single centre experience)

BACKGROUND

Inflammation and malnutrition play an important role in endothelial dysfunction, atherosclerosis and excessive cardiovascular morbidity and mortality in ESRD patients AIM OF THE STUDY: The primary objective is to determine the prevalence of inflammation, malnutrition and atherosclerosis in patients on maintenance haemodialysis. Secondary objective was to determine the association for atherosclerosis with inflammation and malnutrition.

PATIENT AND METHODS

One hundred and one adult patients with end stage renal disease on maintenance haemodialysis who are met with the exclusion criteria were enrolled in this cross sectional study from haemodialysis unit of Baghdad teaching hospital over the period of July/2015 - June 2016. All patients were thoroughly examined and many variables were evaluated (age, gender, blood pressure, diabetes mellitus, serum lipid profile, smoking habits, serum albumin, CRP, calcium, Phosphate, Parathyroid hormone and haemoglobin measurements). All patients underwent a carotid Doppler ultrasound study.

RESULTS

Atherosclerosis was present in 65.3%: 58.4% of patients had malnutrition and 43.6% had inflammation. The association for atherosclerosis and high CRP and low serum albumin is strong and independent of other atherosclerosis risk factors. There is significant inverse and independent correlation between CRP and albumin.

CONCLUSION

Inflammation (high serum CRP) and malnutrition (low serum albumin) in patients on haemodialysis are significantly associated with carotid atherosclerosis. Inflammation was more prevalent in the malnourished patients than in those with normal nutritional status.

Precedent fluctuation of serum hs-CRP to albumin ratios and mortality risk of clinically stable hemodialysis patients

Background

A high sensitivity C-reactive protein to albumin ratio (hs-CRP/Alb) predicts mortality risk in patients with acute kidney injury. However, it varies dynamically. This study was conducted to evaluate whether a variation of this marker was associated with long-term outcome in clinically stable hemodialysis (HD) patients.

Methods

hs-CRP/Alb was checked bimonthly in 284 clinically stable HD outpatients throughout all of 2008. Based on the “slope” of trend equation derived from 5–6 hs-CRP/alb ratios for each patient, the total number of patients was divided into quartiles—Group 1: β≦ −0.13, n = 71; group 2: β>-0.13≦0.003; n = 71, group 3: β>0.003≦0.20; and group 4: β>0.20, n = 71. The observation period was from January 1, 2009 to August 31, 2012.

Results

Group 1+4 showed a worse long-term survival (p = 0.04) and a longer 5-year hospitalization stay than Group 2+3 (38.7±44.4 vs. 16.7±22.4 days, p<0.001). Group 1+4 were associated with older age (OR = 1.03, 95% CI = 1.01–1.05) and a high prevalence of congestive heart failure (OR = 2.02, 95% CI = 1.00–4.11). Standard deviation (SD) of hs-CRP/Alb was associated with male sex (β = 0.17, p = 0.003), higher Davies co-morbidity score (β = 0.16, p = 0.03), and baseline hs-CRP (β = 0.39, p<0.001). Patients with lower baseline and stable trend of hs-CRP/Alb had a better prognosis. By multivariate Cox proportional methods, SD of hs-CRP/alb (HR: 1.05, 95% CI: 1.01–1.08) rather than baseline hs-CRP/Alb was an independent predictive factor for long-term mortality after adjusting for sex and HD vintage.

Conclusion

Clinically stable HD patients with a fluctuating variation of hs-CRP/Alb are characterized by old age, and more co-morbidity, and they tend to have longer subsequent hospitalization stay and higher mortality risk.

Comparison of markers of appetite and inflammation between hemodialysis patients with and without failed renal transplants

OBJECTIVE

The survival of patients returning to hemodialysis (HD) following kidney transplant failure is unfavorable. However, the factors responsible for this poor outcome are largely unknown; chronic inflammation due to failed allograft and malnutrition may contribute to morbidity and mortality. We aim to compare the markers of appetite and malnutrition, and their relation with inflammation in HD patients with and without previous kidney transplantation.

METHODS

Fifty-six patients with failed renal allografts at least 3 months on dialysis (31 men, 25 women; mean age, 46 ± 9 years) and 77 HD patients who never underwent a transplant (43 men, 34 women; mean age, 50 ± 15 years) were included in the study. The appetite and diet assessment tool (ADAT) was used to determine the self reported appetite of patients. Serum concentrations of ghrelin, leptin, insulin like growth factor 1 (IGF-1), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and high-sensitivity C-reactive protein (hs-CRP) were measured. Associations among these variables were analyzed.

RESULTS

There were no significant differences considering age, gender or duration of renal replacement therapy between the 2 groups. The scores from Appetite and Diet Assessment Tool were significantly higher in the failed-transplant group. Serum ghrelin levels were significantly higher and serum albumin levels were significantly lower in the failed-transplant group. Serum leptin levels were similar between 2 groups. In addition, hs-CRP, IL-6, and TNF-α levels, which were used as inflammatory parameters, were significantly higher in the failed-transplant group.

CONCLUSIONS

Elevated serum ghrelin levels and inflammation may cause diminished appetite and malnutrition in patients with failed renal allografts, and higher levels of this hormone seem to be associated with inflammation caused by retained failed allografts.

Relationship Between Erythropoietin Responsiveness, Insulin Resistance, and Malnutrition-Inflammation-Atherosclerosis (Mia) Syndrome in Hemodialysis Patients with Diabetes

Background

This study aimed to explore the relationship between recombinant human erythropoietin (EPO) responsiveness, insulin resistance, and malnutrition-inflammation-atherosclerosis (MIA) syndrome in hemodialysis patients.

Methods

This was an observational cohort study in hemodialysis patients. Adipokines, inflammatory cytokines, and required EPO dosage were measured in diabetes (DM; n=58) and non-diabetes (non-DM; n=58) groups over 48 weeks. Furthermore, the EPO responsiveness index (required EPO dosage divided by hemoglobin) was evaluated with or without MIA syndrome in both groups.

Results

The DM group had significantly higher plasma leptin, interleukin-6 (IL-6), and high sensitivity C-reactive protein (hs-CRP) levels but lower plasma high molecular weight (HMW) adiponectin levels compared to the non-DM group. Although hemoglobin levels were not significantly different, required EPO dosage was significantly higher in the DM group than in the non-DM group, particularly in the presence of MIA syndrome. The DM group with MIA syndrome had significantly higher plasma leptin, IL-6, and hs-CRP levels but lower plasma HMW adiponectin levels compared to the non-DM group with MIA syndrome. There was also a significant association between EPO dosage and homeostasis model assessment for insulin resistance (HOMA-IR), hs-CRP, IL-6, tumor necrosis factor α, leptin, and HMW adiponectin levels in DM patients with MIA syndrome.

Conclusion

Diabetic hemodialysis patients with MIA syndrome have a lower response to EPO and a higher resistance to insulin. This fact may explain the poor outcome of these patients and demonstrate the importance of diagnosis and therapeutic management.

Which components of malnutrition-inflammation-atherosclerosis syndrome are more common in haemodialysis patients with diabetic nephropathy?

AIM

Malnutrition-inflammation-atherosclerosis syndrome (MIA) in haemodialysis (HD) patients is a common clinical condition characterized by increased mortality rate. The aim of this study was to analyze the frequency of MIA components in a selected population of HD patients with and without diabetic nephropathy.

METHODS

The frequency of MIA components was analysed in 49 patients with an over 10-year history of diabetes before initiation of HD (DM group) and 49 non-diabetic HD patients (non-DM group).

RESULTS

The chance for occurrence of atherosclerosis (odds ratio = 3.26) was markedly higher in DM than non-DM subjects. The most frequent MIA component in DM and non-DM subjects was atherosclerosis (67.3% and 40.8%, respectively). Atherosclerosis frequently coexisted with inflammation in both groups (51.5% in DM and 20.0% in non-DM) and less frequently with malnutrition. The frequency of inflammation was only slightly higher in DM, while of malnutrition was similar. Patients with atherosclerosis in the DM group had significantly higher serum concentrations of interleukin-6 than the ones in the non-DM group: 11 (6-24) versus 5 (2-9) pg/mL, respectively (P = 0.002).

CONCLUSIONS

We can conclude that: (i) atherosclerosis is more common in HD patients with diabetic nephropathy; and (ii) this fact may explain the poor outcome of these patients and indicates the challenge in diagnostic and therapeutic management.

Hemodialysis central venous catheters as a source of inflammation and its implications

The mortality rate for end-stage renal disease patients is six times higher than in the general population. Hemodialysis central venous catheter (CVC) utilization has increased by 50% between 1998 and 2004 and data from the United States Renal Data System suggest that 81% of the patients initiate hemodialysis through a CVC. There is evidence that the two observations are linked in both an obvious way (catheter-related sepsis) as well as in a less obvious manner-chronic inflammation. Inflammation is highly prevalent in chronic hemodialysis (CHD) patients and is consistently associated with poor outcomes. Some of the most important consequences of inflammation in CHD include, but are not limited to, cardiovascular disease, uremic protein-energy wasting, erythropoietin hyporesponsiveness, and increased hospitalization and death rates. Use of CVC has been long suspected to play a role in the inflammatory response in CHD patients. Recent studies have shown that the presence of CVCs is associated with higher levels of C-reactive protein (CRP), lower serum albumin values, and lower hemoglobin values. Furthermore, there are data showing that CRP levels decrease following CVC removal. Accordingly, avoidance of CVC represents an effective strategy to limit the inflammatory response in CHD patients and potentially prevent its devastating consequences.

Analysis of the association of polymorphism in the osteoprotegerin gene with susceptibility to chronic kidney disease and periodontitis

BACKGROUND AND OBJECTIVE

Chronic kidney disease (CKD) is a complex disorder, which results in several complications involving disturbance of mineral metabolism. Periodontal disease is an infectious disease that appears to be an important cause of systemic inflammation in CKD patients. Periodontal disease is characterized by clinical attachment loss (CAL) caused by alveolar bone resorption around teeth, which may lead to tooth loss. Osteoprotegerin (OPG) is a key regulator of osteoclastogenesis. Polymorphisms are the main source of genetic variation, and single nucleotide polymorphisms (SNPs) have been reported as major modulators of disease susceptibility. The aim of this study was to investigate the association of a polymorphism located at position -223 in the untranslated region of the OPG gene, previously known as -950, with susceptibility to CKD and periodontal disease.

MATERIAL AND METHODS

A sample of 224 subjects without and with CKD (in hemodialysis) was divided into groups with and without periodontal disease. The OPG polymorphism was analyzed by polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

No association was found between the studied OPG polymorphism and susceptibility to CKD or periodontal disease.

CONCLUSION

It was concluded that polymorphism OPG-223 (C/T) was not associated with CKD and periodontal disease in a Brazilian population. Studies on other polymorphisms in this and other genes of the host response could help to clarify the involvement of bone metabolism mediators in the susceptibility to CKD and periodontal disease.

Serum CRP levels in pre-dialysis patients

BACKGROUND

An elevated serum C-reactive protein (CRP) is strongly associated with morbidity and mortality in dialysis patients. However, the significance of high CRP levels in pre-dialysis patients has not been studied extensively. The aim of this study was to determine the prevalence of elevated serum CRP in pre-dialysis patients and to analyze its correlation with renal function and other inflammatory and nutritional factors.

METHODS

In a cross-sectional study, 100 pre-dialysis patients who had been visited in two outpatient nephrology clinics from 2005 until 2006 and had the serum creatinine >/= 1.5 mg/dL for at least three months were studied. Demographic characteristics, medications, GFR, hemoglobin, as well as inflammatory and nutritional parameters (CRP, Albumin, Fibrinogen, Transferin, Ferritin, TG, Chol, LDL, and HDL) were measured and compared between the patients in regard to the CRP level.

RESULTS

The mean of serum CRP level was 5.7 +/- 5.1mg/L; elevated level were reported in 17 patients (17%). Serum CRP levels was significantly correlated with GFR, albumin, fibrinogen, transferring, and ferritin.

CONCLUSION

Similar to the dialysis population, we found that serum CRP was elevated in pre-dialysis patients. In addition, a positive correlation between serum CRP levels and several inflammatory factors was found. CRP serum level was also negatively correlated with GFR, the indicator of renal function.

Cytokine dysregulation in chronic kidney disease: how can we treat it?

As the kidney is the major site for elimination of many cytokines, the delicate equilibrium of pro-inflammatory cytokines and their inhibitors is clearly dysregulated in chronic kidney disease (CKD) patients. The consequences of the altered immune response in uremia lead to a state of persistent inflammation which is highly prevalent among CKD patients and is linked to complications such as the development of protein-energy wasting and atherosclerotic vascular disease. The present review aims at reviewing this complex orchestration of uremic cytokines beyond the well-studied interleukin-6 and tumor necrosis factor-alpha. Finally, we update our current understanding on anti-inflammatory treatment strategies in CKD patients, including nutritional and lifestyle measurements, pharmacological intervention and specific anticytokine strategies targeting the dialytic procedure.

A proposed nomenclature and diagnostic criteria for protein-energy wasting in acute and chronic kidney disease

The recent research findings concerning syndromes of muscle wasting, malnutrition, and inflammation in individuals with chronic kidney disease (CKD) or acute kidney injury (AKI) have led to a need for new terminology. To address this need, the International Society of Renal Nutrition and Metabolism (ISRNM) convened an expert panel to review and develop standard terminologies and definitions related to wasting, cachexia, malnutrition, and inflammation in CKD and AKI. The ISRNM expert panel recommends the term 'protein-energy wasting' for loss of body protein mass and fuel reserves. 'Kidney disease wasting' refers to the occurrence of protein-energy wasting in CKD or AKI regardless of the cause. Cachexia is a severe form of protein-energy wasting that occurs infrequently in kidney disease. Protein-energy wasting is diagnosed if three characteristics are present (low serum levels of albumin, transthyretin, or cholesterol), reduced body mass (low or reduced body or fat mass or weight loss with reduced intake of protein and energy), and reduced muscle mass (muscle wasting or sarcopenia, reduced mid-arm muscle circumference). The kidney disease wasting is divided into two main categories of CKD- and AKI-associated protein-energy wasting. Measures of chronic inflammation or other developing tests can be useful clues for the existence of protein-energy wasting but do not define protein-energy wasting. Clinical staging and potential treatment strategies for protein-energy wasting are to be developed in the future.

Association between Vitamin D Receptor Gene Polymorphisms and Susceptibility to Chronic Kidney Disease and Periodontitis

BACKGROUND/AIMS

Chronic kidney disease (CKD) and periodontitis (PD) are serious public-health concerns. Vitamin D is a fat-soluble steroid hormone that interacts with its nuclear receptor (VDR) to regulate a variety of biological processes, such as bone metabolism, immune response modulation and transcription of several genes involved in CKD and PD disease mechanisms. The aim of this work was to investigate the association between polymorphisms in the VDR gene and end-stage renal disease (ESRD) and PD.

METHODS

222 subjects with and without ESRD (in hemodialysis) were divided into groups with and without PD. Polymorphisms TaqI and BsmI in the VDR gene were analyzed by PCR restriction fragment length polymorphism. The significance of differences in allele, genotype and haplotype frequencies between groups was assessed by the chi2 test (p value <0.05) and odds ratio (OR).

RESULTS

Allele G was associated with protection against ESRD: groups without versus with ESRD (GG) x (GA+AA): OR = 2.5, 95% CI = 1.4-4.6, p = 0.00; (G x A): OR = 1.5, 95% CI = 1.0-2.3, p = 0.02; (TG + CG) x (TA + CA): OR = 1.5, 95% CI = 1.0-2.3, p = 0.02. No association was observed between the study polymorphisms and susceptibility to or protection against PD.

CONCLUSION

Allele G of the VDR BsmI polymorphism was associated with protection against ESRD.

Quotidian hemodialysis and inflammation associated with chronic kidney disease

The mortality rate of chronic dialysis patients in the United States is 24% per year per the 2006 United States Renal Data System. Although there have been marked improvements in dialysis technology, cardiovascular disease is the principal cause of mortality in end-stage renal disease patients. Inflammation and left ventricular hypertrophy both contribute to atherosclerosis. Hemodialysis 3 times a week is the most commonly used form of dialysis in the United States. The multicenter hemodialysis (HEMO) study hypothesized that an increase in dialysis dose and use of high-flux membranes would improve mortality and decrease morbidity. This study failed to show decreases in mortality. In other studies, however, there appears to be improved morbidity with more frequent dialysis including daily nocturnal hemodialysis and short-daily hemodialysis. The more frequent dialysis may have some beneficial effect on the inflammatory process that occurs in end-stage renal disease.

Inflammation as the key interface of the medical and nutrition universes: a provocative examination of the future of clinical nutrition and medicine

There has been tremendous interest in inflammation by researchers, the medical community, and the lay public. Modulation of injury response is felt to represent a tenuous balance of pro- and anti-inflammatory cytokines. Adverse outcomes may result from severe, sustained, or repeated bouts of inflammation. A critical observation is that nutrition support alone is inadequate to prevent muscle loss during active inflammation. It is necessary to take inflammation into consideration in conducting appropriate nutrition assessment, intervention, and monitoring. A host of medical conditions are actually inflammatory states that have important implications for nutrition care. Multifaceted interventions that may include anti-inflammatory diets, glycemic control, physical activity, appetite stimulants, anabolic agents, anti-inflammatory agents, anticytokines, and probiotics, will be necessary to blunt undesirable aspects of inflammatory response to preserve body cell mass and vital organ functions. Nutrition practitioners can seize this opportunity to be a part of the future medical team that brings highly individualized patient care to the bedside.

Inflammation in end-stage renal disease: the hidden enemy

Cardiovascular disease (CVD) remains the major cause of morbidity and mortality in end-stage renal disease (ESRD) patients. As traditional risk factors cannot alone explain the unacceptable high prevalence and incidence of CVD in this high-risk population, inflammation (interrelated to insulin resistance, oxidative stress, wasting and endothelial dysfunction) has been suggested to be a significant contributor. Indeed, several different inflammatory biomarkers, such as high sensitivity C-reactive protein (hs-CRP), have been shown to independently predict mortality in ESRD patients. As CRP is so strongly associated with vascular disease it has been suggested that this hepatic-derived protein is not only a marker, but also a mediator, of vascular disease. Although in vitro data from studies on endothelial cells, monocytes-macrophages and smooth muscle cells support a direct role for CRP in atherogenesis, data from studies performed in vivo have been controversial. The causes of the highly prevalent state of inflammation in ESRD are multiple, including inflammatory signals associated with the dialysis procedure, decreased renal function, volume overload, comorbidity and intercurrent clinical events. As the prevalence of inflammation varies considerably between continents and races, dietary and/or genetic factors may have an impact on inflammation in ESRD. Elevated CRP in dialysis patients could be evaluated at three different levels: (i) national/regional level; (ii) dialysis unit level; and (iii) individual patient level.

Why don't fistulas mature?

Fistula maturation requires a compliant and responsive vasculature capable of dilating in response to the increased velocity of blood flowing into the newly created low-resistance circuit. Successful maturation to a high volume flow circuit capable of sustaining hemodialysis typically occurs within the first few weeks after creation. Failure to achieve maturation within 4-8 weeks should prompt a search for reversible etiologies; however, an accepted definition of maturation, particularly for patients not yet on dialysis remains elusive. The most commonly identified etiology is neointimal hyperplasia typically occurring in the juxta-anastomotic vein. However, failed maturation has also been reported secondary to impaired arterial and venous dilation and accessory veins. The exact frequency of each of these etiologies is unclear. Understanding the etiologies of impaired fistula maturation will focus future studies of targeted interventions to improve the rate of fistula maturation and increase the number of dialysis patients with a functioning autogenous fistula.

Recent advances in understanding the malnutrition-inflammation-cachexia syndrome in chronic kidney disease patients: What is next?

Several recent clinical trials using single modalities to correct the conventional cardiovascular risk factors in patients with chronic kidney disease (CKD) or to improve dialysis dose and techniques in maintenance dialysis patients have failed despite the high rate of cardiovascular mortality in these individuals. Protein-energy malnutrition and inflammation, two relatively common and concurrent conditions in CKD patients, have been implicated as the main cause of poor short-term survival in this population. The "malnutrition-inflammation-cachexia syndrome" (MICS) appears to be the main cause of worsening atherosclerotic cardiovascular disease in the CKD population. The MICS is associated with low serum cholesterol and homocysteine levels and leads to "cachexia in slow motion." Hence a reverse epidemiology of cardiovascular risk factors is observed in dialysis patients with a paradoxical association of obesity, hypercholesterolemia, and hyperhomocysteinemia with better survival. Correction of MICS can potentially ameliorate the cardiovascular epidemic in CKD patients. Because MICS is multifactorial, its correction will require an integral approach rather than a single intervention. The ongoing obsession with conventional cardiovascular risk factors largely reflecting overnutrition in a population that suffers from the short-term consequences of undernutrition and excessive inflammation may well be fruitless. Clinical trials focusing on the causes and consequences of MICS and its modulation using nutritional interventions may be the key to improving survival in these individuals.

Analysis of cardiovascular disease and kidney outcomes in multidisciplinary chronic kidney disease clinics: complex disease requires complex care models

PURPOSE OF REVIEW

Chronic kidney disease is recognized as being highly prevalent in the population, and associated with morbidity and mortality relative to the general population. The complexity of patients and the multiplicity of interventions required to maintain health has forced clinicians to develop different models of healthcare delivery. This publication reviews the current literature on specific interventions to reduce progression of chronic kidney disease and cardiovascular disease, and studies the examination of outcomes of patients exposed to different healthcare delivery models. Specifically we examine the rationale and outcomes of those seen in multidisciplinary clinics.

RECENT FINDINGS

Current evidence supports the use of rennin-angiotensin system blockers, reduction of blood pressure and proteinuria and phosphate control. Additional less robust studies support the need for attention to anemia, hyperparathryoidism, and other more "kidney specific" risk factors. The attendance of identified chronic kidney disease patients at multidisciplinary clinics appears to improve survival once dialysis is started. Despite aggressive management, not all patients are able to meet clinical targets associated with improved outcomes.

SUMMARY

The recognition of the complexity of chronic kidney disease care and the need to develop and test models of care in addition to the single interventions is a challenge for both researchers and clinicians. Current data support the use of multidisciplinary clinics in improving outcomes of referred patients. Future research will help to refine and define appropriate care models for this growing chronic kidney disease population.

IL-10, IL-6, and TNF-alpha: central factors in the altered cytokine network of uremia--the good, the bad, and the ugly

It has been increasingly apparent that wasting and cardiovascular disease (CVD) is associated with a persistent systemic inflammatory response in end-stage renal disease (ESRD) patients. The reasons for the increased risk of inflammation in ESRD patients appear to be complex, including non-dialysis as well as dialysis-related factors. The combination of an impaired immune response coupled with persistent immune stimulation may have a role in the low-grade systemic inflammation and altered cytokine balance that characterizes the uremic state and which may translate into increased risk for vascular disease. The accelerated atherosclerotic process of ESRD may involve several interrelated processes, such as oxidative stress, endothelial dysfunction, and vascular calcification, in a milieu of constant low-grade inflammation with impaired function of neutrophils and T cells, as well as a dysregulated cytokine network. Although a large number of pro- and anti-inflammatory cytokines are of importance, available data suggest that the anti-inflammatory cytokine interleukin (IL)-10 and the mainly proinflammatory cytokines IL-6 and tumor necrosis factor-alpha (TNF-alpha) may play important roles in the development of Th imbalance, CVD and wasting in the uremic milieu. Given the strong association between proinflammatory cytokines and complications common in ESRD, such as vascular calcification and wasting, the potential role of both general and targeted anticytokine treatment strategies in ESRD patients needs further evaluation.

Multinutrient Oral Supplements and Tube Feeding in Maintenance Dialysis: A Systematic Review and Meta-Analysis

BACKGROUND

This systematic review aims to determine the potential benefits of enteral multinutrient support (oral or tube) in patients with chronic kidney disease (CKD) receiving maintenance dialysis.

METHODS

Studies of multinutrient oral supplements and enteral tube feeding that involved comparisons of nutritional support versus routine care (ie, usual diet), disease-specific formulae (with adapted macronutrient and micronutrient composition for use in maintenance dialysis patients) versus standard formulae, and enteral tube feeding versus parenteral nutrition are included in this review. The outcome measures sought were clinical (quality of life, complications, and mortality), biochemical (albumin and electrolyte levels), and nutritional (dietary intake and anthropometry). Meta-analyses were performed when possible.

RESULTS

This review of 18 studies (5 randomized controlled trials [RCTs], 13 non-RCTs) suggests that enteral nutritional support increased total (energy and protein) intake and increased serum albumin concentration by 0.23 g/dL (2.3 g/L; 95% confidence interval, 0.037 to 0.418 g/dL [0.37 to 4.18 g/L]; 1 RCT, 2 non-RCTs), with little effect on electrolyte status (serum phosphate and potassium). Few studies reported clinical outcome, and there was insufficient information to compare disease-specific versus standard formulae or enteral versus parenteral nutrition.

CONCLUSION

This systematic review suggests that enteral multinutrient support significantly increases serum albumin concentrations and improves total dietary intake. This may improve clinical outcome, especially in malnourished patients, but insufficient published data exist to examine this. Additional research is required to investigate clinical, economic, and nutritional consequences of using oral supplements and tube feeding (using standard or disease-specific feeds) in patients with CKD receiving maintenance dialysis.

Kidney insufficiency and nutrient-based modulation of inflammation

PURPOSE OF REVIEW

Patients with chronic kidney disease have a high cardiovascular mortality rate. Despite recent advances in dialysis techniques, over 20% of US dialysis patients die every year. Protein-energy malnutrition and inflammation are common and usually concurrent in chronic kidney disease patients, and have been implicated as the main cause of high mortality. We reviewed the pathophysiology of the malnutrition-inflammation complex syndrome and its potential modulation by dietary and other nutritional interventions in chronic kidney disease patients.

RECENT FINDINGS

The malnutrition-inflammation complex syndrome is a main cause of the atherosclerotic cardiovascular disease epidemic in chronic kidney disease. This may be by virtue of the syndrome's inflammatory components. Malnutrition and inflammation lead to weight loss over time, i.e. cachexia in slow motion, and result in decreased serum cholesterol and homocysteine levels. A 'reverse epidemiology' of cardiovascular risk factors is observed in chronic kidney disease, in that obesity, hypercholesterolemia and hyperhomocysteinemia are paradoxically associated with better survival. Among the possible etiologies of the malnutrition-inflammation complex syndrome, anorexia, low nutrient intake and oxidative stress are theoretically amenable to dietary modulation; however, the bulk of findings are epidemiological.

SUMMARY

There is no consensus as to how to correct the malnutrition-inflammation complex syndrome in chronic kidney disease patients. Because the malnutrition-inflammation complex syndrome is multifactorial, its correction probably requires a battery of simultaneous interventions, rather than one single modality. Clinical trials focusing on the syndrome are currently non-existent and are therefore urgently required to improve poor clinical outcome in chronic kidney disease patients.

End-stage renal disease--not an equal opportunity disease: the role of genetic polymorphisms

Despite several decades of development in renal replacement therapy, end-stage renal disease (ESRD) patients continue to have markedly increased morbidity and mortality especially caused by cardiovascular disease (CVD). This shows that current strategies, e.g. the focus on dialysis adequacy, to improve the clinical outcome in ESRD patients have to be complemented by novel approaches. Although traditional risk factors are common in dialysis patients they cannot alone explain the unacceptably high prevalence of CVD in this patient group. Much recent interest has therefore focused on the role of various nontraditional cardiovascular risk factors, such as inflammation, vascular calcification and oxidative stress. Recent studies show that genetic factors, such as DNA single nucleotide polymorphisms, may significantly influence the immune response, the levels of inflammatory markers, as well as the prevalence of atherosclerosis in this patient group. To elucidate the respective roles of DNA polymorphisms in genes that encode inflammatory markers (such as IL-10, IL-6 and TNF-alpha) and other factors that may affect the development of atherosclerosis (such as apolipoprotein E, transforming growth factor and fetuin-A), sufficiently powered studies are needed in which genotype, the protein product and the specific phenotype all are analysed in relation to outcome. The recent developments in the field of genetics have opened up entirely new possibilities to understand the impact of genotype on disease development and progress and thus offer new options and strategies for treatment. It seems conceivable that in the near future, prognostic or predictive multigene DNA assays will provide the nephrological community with a more precise approach for the identification of "high-risk" ESRD patients and the development of accurate individual treatment strategies. For this purpose, integrative studies on genotype-phenotype associations and impact on clinical outcome are needed.

Role of interleukin-1beta in the development of malnutrition in chronic renal failure patients

Protein-energy malnutrition and wasting are common among patients with end-stage renal disease (ESRD) and these complications are strongly associated with poor survival in these patients. Whereas both under- and overweight predict in increased mortality risk in the general population, a high body mass index is associated with better outcome in ESRD patients. Circulating levels of pro-inflammatory cytokines are markedly elevated in uremia and also predictor of a poor clinical outcome in ESRD patients. Interleukin-1beta (IL-1beta), which is a major pro-inflammatory cytokine, may further amplify inflammation and lead to malnutrition, through inducing anorexia, and muscle wasting due to increased protein breakdown. Several clinical studies have shown that the circulating level of IL-1beta may affect nutritional status, especially body composition. Several IL-1 gene cluster polymorphisms were reported, and they may affect the prevalence of cytokine-mediated diseases. Although a number of factors are related to malnutrition and wasting in ESRD, pro-inflammatory cytokines, such as IL-1beta, may play an important role. This could in part be due to genetic factors. Further research, especially regarding the IL-1 gene cluster polymorphisms, is necessary to determine this hypothesis.