Characteristics and effects of inflammation in end-stage renal disease

Effect of Diet and Supplementation on Serum Vitamin C Concentration and Antioxidant Activity in Dialysis Patients

Loss of vitamin C, especially in conjunction with an inadequate supply, can lead to decreased plasma concentrations of vitamin C. This in turn can lead to overt or subclinical deficiency. The present study aimed to evaluate the effects of diet and supplementation on vitamin C concentrations and serum antioxidant activity (FRAP) in hemodialysis (HD) patients. Sixty-eight HD patients participated in the study. In all of them, the diet was initially determined, and they were divided into five groups according to the diet and supplementation used. Group 1 received an unchanged diet, considered by them to be optimal; in group 2, the standard diet used in HD patients was introduced; in group 3, a standard diet enriched with natural antioxidants was employed; in group 4, a standard diet as in group 2 was used, but enriched with supplements (vitamin C, vitamin E, Se, and Zn). In contrast, group 5 consisted of HD patients with coexisting diabetes. Vitamin C serum levels were determined by high-performance liquid chromatography HPLC and antioxidant activity by The Ferric Reducing Ability of Plasma FRAP. The study shows that a well-chosen diet can slow the build-up of malnutrition and increase antioxidant activity as measured by the FRAP method in the blood of hemodialysis patients. Vitamin C supplementation can improve antioxidant status in hemodialysis patients. * The results presented in this paper complement our study, which assessed the effect of diet on the activity of erythrocyte antioxidant enzymes: Catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px), but also on the concentrations of non-enzymatic antioxidants (tocopherols, carotenoids, and vitamin C) in hemodialysis patients. In the study, plasma malondialdehyde (MDA) concentrations were assessed as an indicator of oxidative damage.

High Neutrophil-to-Lymphocyte and Platelet-to-Lymphocyte Ratios Are Associated with a Higher Risk of Hemodialysis Vascular Access Failure

Our aim was to determine the predictive role of the preoperative neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) in vascular access malfunctioning in patients who had undergone their first native arterio-venous fistula (AVF) for hemodialysis. Methods: This was a single-center retrospective observational study. All patients who underwent the procedure of the creation of a first native AVF for hemodialysis from January 2019 to December 2020 were considered eligible to be part of this study. Reinterventions for AVF malfunctioning were registered and the population was subdivided into two groups with respect to AVF malfunctioning. ROC curves were obtained to find the appropriate cut-off values for the NLR and PLR. A multivariate analysis was used to identify the independent predictors for an AVF malfunction. Kaplan−Meier curves were used to evaluate the AVF patency rates. A total of 178 patients were enrolled in the study, of them 70% (n = 121) were male. The mean age was 67.5 ± 12 years. Reinterventions for AVF malfunctioning were performed on 102 patients (57.3%). An NLR > 4.21 and a PLR > 208.8 was selected as the cut-off for AVF malfunctioning. The study population was divided into two groups depending on the NLR and PLR values of the individual. For the NLR < 4.21 group, the AVF patency rates were 90.7%, 85.3%, and 84% at the 3-, 6-, and 12-month follow-up, respectively, and 77.5%, 65.8%, and 39.3% at 3, 6, and 12 months for the NLR > 4.21 group, respectively (p < 0.0001). For the PLR < 208.8 group, the patency rates were 85.6%, 76.7%, and 67.7% at the 3-, 6-, and 12-month follow-up. For the PLR > 208.28 group, the patency rates were 80.8%, 71.2%, and 50.7% for the 3-, 6-, and 12-month follow-up, respectively (p = 0.014). The multivariate analysis highlighted that diabetes mellitus, the neutrophil count, the lymphocyte count, and the NLR were independent risk factors for an AVF failure. In our experience, the NLR and PLR are useful markers for the stratification of vascular access failure in hemodialysis patients. The inexpensive nature and ready availability of the values of these biomarkers are two points of strength for everyday clinical practice.

Optimizing Decellularization Strategies for the Efficient Production of Whole Rat Kidney Scaffolds

BACKGROUND

Renal dysfunction remains a global issue, with chronic kidney disease being the 18th most leading cause of death, worldwide. The increased demands in kidney transplants, led the scientific society to seek alternative strategies, utilizing mostly the tissue engineering approaches. Unlike to perfusion decellularization of kidneys, we proposed alternative decellularization strategies to obtain acellular kidney scaffolds. The aim of this study was the evaluation of two different decellularization approaches for producing kidney bioscaffolds.

METHODS

Rat kidneys from Wistar rats, were submitted to decellularization, followed two different strategies. The decellularization solutions used in both approaches were the same and involved the use of 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate and sodium dodecyl sulfate buffers for 12 h each, followed by incubation in a serum medium. Both approaches involved 3 decellularization cycles. Histological analysis, biochemical and DNA quantification were performed. Cytotoxicity assay and repopulation of acellular kidneys were also applied.

RESULTS

Histological, biochemical and DNA quantification confirmed that the 2nd approach had the best outcome regarding the kidney composition and cell elimination. Acellular kidneys from both approaches were successfully recellularized.

CONCLUSION

Based on the above data, the production of kidney scaffolds with the proposed cost- effective decellularization approaches, was efficient.

Infectious Complications in Chronic Dialysis Patients

Surprisingly little formal research has examined the issue of major bacterial infections in chronic dialysis patients. This is a surprising situation, because uremia is a classic state of immune hyporesponsiveness, and infection rates are believed to be several times higher in dialysis populations than in age-matched segments of the general population. The present paper focuses on the clinical epidemiology of major bacterial infections in dialysis patients, associations between bacterial infections and cardiovascular disease, and interventions aimed at averting these infections.

Factors affecting TST level in patients undergoing dialysis: a multicenter study

INTRODUCTION

The risk of TB is increased in patients with chronic kidney disease (CKD) when compared with individuals with normal renal function. We aimed to determine tuberculin skin test (TST) response and the factors which might affect the response in patients with CKD undergoing dialysis in this study.

METHODS

The purified protein derivative solution was administered to the patients and the diameter of induration was measured. Additionally, the age, gender and smoking status of the patients were interrogated. Comorbidities were recorded both by patients' self-reports and data from the hospital files. The number of Bacille Calmette-Guerin (BCG) scars was recorded by checking both shoulders.

FINDINGS

The study was conducted with a total of 371 patients (194 men and 177 women). The mean age was 60.09 ± 15.88, TST was 6.99 ± 6.9, duration of dialysis was 4.44 ± 4.5 (3.8-0.1,24). A total of 229 patients have comorbodities (61.7%, the most frequent was hypertension). Logistic regression model was performed. Gender, vitamin D treatment and high parathormone (PTH) levels remained in the final stage of the analysis and vitamin D intake and PTH levels were detected to be statistically significant (P = 0.002, 0.007, respectively).

DISCUSSION

This study is the first study which showed a correlation between TST negativity and increased PTH levels and receiving vitamin D treatment. Starting from this point, it was concluded that PTH may suppress the immune system and especially cellular immunity.

Association of brain-derived neurotrophic factor and interleukin-6 serum levels with depressive and anxiety symptoms in hemodialysis patients

OBJECTIVE

This study assessed the possible association of serum brain-derived neurotrophic factor (BDNF) and interleukin-6 (IL-6) with depressive and anxiety symptoms in hemodialysis (HD) patients.

METHOD

An analytical cross-sectional study was conducted over 274 HD patients from March to October 2017. The Hospital Anxiety and Depression Scale (HADS) was utilized to evaluate depressive (HADS-D) and anxiety (HADS-A) symptoms. The HADS-D/A is a self-report instrument that has a maximum score of 21. Serum BDNF and IL-6 were measured using enzyme-linked immunosorbant assay (ELISA).

RESULTS

Serum IL-6 was significantly higher in patients with depressive symptoms compared to normal (20.47 ± 4.27 pg/mL for HADS-D ≥11 versus 9.26 ± 1.59 pg/mL for HADS-D <7, p = 0.014). Multivariable regression analysis revealed that IL-6, education level, hypertension, and dialysis duration were significant predictors of HADS-D. Also, gender, education level, hypertension, and the number of dialysis sessions/week were significant predictors of HADS-A. Significant positive correlation was shown between HADS-D and IL-6 (r = 0.1729, p = 0.004).

CONCLUSION

Collectively, HD patients with depressive symptoms showed higher levels of IL-6, supporting previous findings that the circulating inflammatory mediator IL-6 can be used as a biomarker for prediction of depressive symptoms in HD patients. Further longitudinal or interventional studies are needed to further validate this association.

Effect of Infla-Kine supplementation on the gene expression of inflammatory markers in peripheral mononuclear cells and on C-reactive protein in blood

Background

Chronic inflammation is a predisposing factor to numerous degenerative diseases including cancer, heart failure and Alzheimer’s disease. Infla-Kine is a natural supplement comprised of a proprietary blend of Lactobacillus fermentum extract, burdock seed (arctigenin), zinc, alpha lipoic acid, papaya enzyme and an enhanced absorption bio-curcumin complex (BCM-95^®).

Methods

Infla-Kine was administered twice daily to 24 health volunteers for 4 weeks. Quantitative RT-PCR was used to assess mRNA transcripts of IL-1b, IL8, IL-6, NF-κB, and TNF-α from peripheral blood mononuclear cells (PBMC). C reactive protein (CRP) was measured from serum. Additionally, quality of life questionnaires were employed to assess general feeling of well-being. Assessments were made before treatment and at conclusion of treatment (4 weeks).

Results

As compared to pre-treatment, after 4 weeks, a statistically significant reduction of IL8, IL-6, NF-κB, and TNF-α transcripts was observed in PBMC. Furthermore, reduction of IL-1b transcript and serum CRP was observed but did not reach statistical significance. Quality of life improvements were most prevalent in muscle and joint pains.

Conclusions

Overall, our data demonstrate that twice daily administration of Infla-Kine for 4 weeks reduces inflammatory markers and quality of life in healthy volunteers.

A single center, open-label, randomized, parallel group study assessing the relationship between asymptomatic bacteriuria and inflammation in maintenance hemodialysis patients

INTRODUCTION

The significance of asymptomatic bacteriuria in maintenance hemodialysis (MHD) patients remains controversial. We hypothesized that the presence of asymptomatic bacteriuria as a sole clinical manifestation of urinary tract infection (UTI) in asymptomatic MHD patient may contribute to the chronic inflammatory response. Our aim was to explore the relationship between asymptomatic bacteriuria and elevated levels of inflammatory markers in MHD patients.

METHODS

A randomized open-label single center study of 114 MHD patients was conducted. Forty-six patients presented negative urine culture and 41 subjects were excluded due to different reasons. The remaining 27 patients (mean age of 71.5 ± 12.2 years, 63% men), fulfilling the criteria for having asymptomatic bacteriuria, were randomly assigned to either the treatment group (13 patients) or the observational group (14 subjects). The treatment group received 7 days of antibiotic treatment given according to bacteriogram sensitivity. After 3 months of follow-up all measurements of the study were repeated. The primary end point was change in inflammatory biomarkers from baseline by the end of the study.

FINDINGS

There were no statistically significant differences in white blood cell changes (P = 0.27), ferritin (P = 0.09), C-reactive protein (P = 0.90), and interleukin-6 (P = 0.14) levels between the groups from baseline to the end of study or at the end of the study. Analyzing cross-sectional data, asymptomatic bacteriuria was found to not be a predictor of higher levels of inflammatory parameters at baseline.

DISCUSSION

Asymptomatic bacteriuria is not a modifiable risk factor for chronic inflammation in the MHD population.

Optimizing haemodialysate composition

Survival and quality of life of dialysis patients are strictly dependent on the quality of the haemodialysis (HD) treatment. In this respect, dialysate composition, including water purity, plays a crucial role. A major aim of HD is to normalize predialysis plasma electrolyte and mineral concentrations, while minimizing wide swings in the patient's intradialytic plasma concentrations. Adequate sodium (Na) and water removal is critical for preventing intra- and interdialytic hypotension and pulmonary edema. Avoiding both hyper- and hypokalaemia prevents life-threatening cardiac arrhythmias. Optimal calcium (Ca) and magnesium (Mg) dialysate concentrations may protect the cardiovascular system and the bones, preventing extraskeletal calcifications, severe secondary hyperparathyroidism and adynamic bone disease. Adequate bicarbonate concentration [HCO₃⁻] maintains a stable pH in the body fluids for appropriate protein and membrane functioning and also protects the bones. An adequate dialysate glucose concentration prevents severe hyperglycaemia and life-threating hypoglycaemia, which can lead to severe cardiovascular complications and a worsening of diabetic comorbidities.

Reverse epidemiology in different stages of heart failure

BACKGROUND

In heart failure (HF), traditional cardiovascular risk factors (RF) as body mass index (BMI), total cholesterol (TC) and systolic blood pressure (SBP) are associated with better survival. It is unknown at which time point along the disease continuum the adverse impact of these RF ceases and may 'start to reverse'. We analyzed the distribution of RF and their association with survival across HF stages.

METHODS

We pooled data from four cohort studies from the German Competence Network HF. Employing ACC/AHA-criteria, patients were allocated to stage A (n=218), B (n=1324), C1 (i.e., New York Heart Association [NYHA] classes I & II; n=1134), and C2+D (NYHA III & IV; n=639).

RESULTS

With increasing HF severity median age increased (63/67/67/70 years), whereas the proportion of females (56/52/37/35%), median BMI (26.1/28.8/27.7/26.6 kg/m(2)), TC (212/204/191/172 mg/dl), and SBP (140/148/130/120 mmHg) decreased (P<0.001 for trend for all). In the total cohort, higher levels of all RF were associated with better survival, even after extensive adjustment for multiple confounders. If analyses were stratified, however, a higher RF burden predicted better survival only in clinically symptomatic patients: hazard ratio (HR) per +2 kg/m(2) BMI 0.91 (95% confidence interval 0.88; 0.95); per +10 mg/dl TC 0.93 (0.92; 0.95); per +5 mmHg SBP 0.94 (0.92; 0.95).

CONCLUSION

In this well-characterized sample of patients representing the entire HF continuum, reverse associations were only consistently observed in symptomatic HF stages. Our data indicate that the phenomenon of a "reverse epidemiology" in HF is subject to significant selection bias in less advanced disease.

Natural history of skeletal muscle mass changes in chronic kidney disease stage 4 and 5 patients: an observational study

Cross-sectional studies in dialysis demonstrate muscle wasting associated with loss of function, increased morbidity and mortality. The relative drivers are poorly understood. There is a paucity of data regarding interval change in muscle in pre-dialysis and dialysis-dependant patients. This study aimed to examine muscle and fat mass change and elucidate associations with muscle wasting in advanced CKD.

134 patients were studied (60 HD, 28 PD, 46 CKD 4–5) and followed up for two years. Groups were similar in age, sex and diabetes prevalence. Soft tissue cross-sectional area (CSA) was measured annually on 3 occasions by a standardised multi-slice CT thigh. Potential determinants of muscle and fat CSA were assessed. Functional ability was assessed by sit-to-stand testing.

88 patients completed follow-up (40 HD, 16 PD, 32 CKD). There was a significant difference in percentage change in muscle CSA (MCSA) over year 1, dependant on treatment modality (χ² = 6.46; p = 0.039). Muscle loss was most pronounced in pre-dialysis patients. Muscle loss during year 1 was partially reversed in year 2 in 39%. Incident dialysis patients significantly lost MCSA during the year which they commenced dialysis, but not the subsequent year. Baseline MCSA, change in MCSA during year 1 and dialysis modality predicted year 2 change in MCSA (adjusted R² = 0.77, p<0.001). There was no correlation between muscle or fat CSA change and any other factors. MCSA correlated with functional testing, although MCSA change correlated poorly with change in functional ability.

These data demonstrate marked variability in MCSA over 2 years. Loss of MCSA in both pre-dialysis and established dialysis patients is reversible. Factors previously cross-sectionally shown to correlate with MCSA did not correlate with wasting progression. The higher rate of muscle loss in undialysed CKD patients, and its reversal after dialysis commencement, suggests that conventional indicators may not result in optimal timing of dialysis initiation.

Accumulation of retained nonfunctional arteriovenous grafts correlates with severity of inflammation in asymptomatic ESRD patients

BACKGROUND

The contribution of multiple retained nonfunctional arteriovenous grafts (AVGs) to the burden of chronic inflammation in chronic hemodialysis patients has not been well studied. Here, we sought to evaluate the association between plasma levels of C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha) and albumin and the number of retained nonfunctional AVGs.

METHODS

This cross-sectional study enrolled 91 prevalent patients undergoing in-center hemodialysis without evidence of infection or inflammation. A baseline blood sample was obtained at study enrollment. A general linear model (GLM) was used to compare levels of biomarkers of systemic inflammation across groups defined by the number of retained, nonfunctional AVGs.

RESULTS

A total of 43 patients had one or more retained thrombosed AVG and had significantly greater plasma log-CRP levels compared with patients without a previous AVG (P= 0.036), regardless of the current AV access type. Using a GLM, we found that for every additional retained thrombosed AVG, plasma log-CRP, log-IL-6 and TNF-alpha concentrations increased significantly by 0.30 mg/L (P= 0.011), 0.18 pg/mL (P= 0.046) and 0.72 pg/mL (P= 0.046), respectively, following adjustment.

CONCLUSIONS

Hence, the severity of inflammation increases with the number of retained nonfunctional AVG's, suggesting that AVG accumulation may contribute to the cardiovascular morbidity and mortality associated with chronic inflammation in asymptomatic end-stage renal disease (ESRD) patients. Further study is indicated to determine whether patients with one or more thrombosed, retained AVG may benefit from periodic screening with CRP monitoring to identify those patients who may benefit from AVG resection.

Renalase protects against ischemic AKI

Elevated levels of plasma catecholamines accompany ischemic AKI, possibly contributing the inflammatory response. Renalase, an amine oxidase secreted by the proximal tubule, degrades circulating catecholamines and reduces myocardial necrosis, suggesting that it may protect against renal ischemia reperfusion injury. Here, mice subjected to renal ischemia reperfusion injury had significantly lower levels of renalase in the plasma and kidney compared with sham-operated mice. Consistent with this, plasma NE levels increased significantly after renal ischemia reperfusion injury. Furthermore, renal tubular inflammation, necrosis, and apoptosis were more severe and plasma catecholamine levels were higher in renalase-deficient mice subjected to renal ischemia reperfusion compared with wild-type mice. Administration of recombinant human renalase reduced plasma catecholamine levels and ameliorated ischemic AKI in wild-type mice. Taken together, these data suggest that renalase protects against ischemic AKI by reducing renal tubular necrosis, apoptosis, and inflammation, and that plasma renalase might be a biomarker for AKI. Recombinant renalase therapy may have potential for the prevention and treatment of AKI.

Hypoxia and oxidative stress markers in pediatric patients undergoing hemodialysis: cross section study

Background

Tissue injury due to hypoxia and/or free radicals is common in a variety of disease processes. This cross-sectional study aimed to investigate effect of chronic kidney diseases (CKD) and hemodialysis (HD) on hypoxia and oxidative stress biomarkers.

Methods

Forty pediatric patients with CKD on HD and 20 healthy children were recruited. Plasma hypoxia induced factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) were measured by specific ELISA kits while, total antioxidant capacity (TAC), total peroxide (TPX), pyruvate and lactate by enzymatic/chemical colorimetric methods. Oxidative stress index (OSI) and lactate/pyruvate (L/P) ratio were calculated.

Results

TAC was significantly lower while TPX, OSI and VEGF were higher in patients at before- and after-dialysis session than controls. Lactate and HIF-1α levels were significantly higher at before-dialysis session than controls. Before dialysis, TAC and L/P ratio were lower than after-dialysis. In before-dialysis session, VEGF correlated positively with pyruvate, HIF-1α and OSI correlated positively with TPX, but, negatively with TAC. In after-dialysis session, HIF-1α correlated negatively with TPX and OSI; while, OSI correlated positively with TPX.

Conclusions

CKD patients succumb considerable tissue hypoxia with oxidative stress. Hemodialysis ameliorated hypoxia but lowered antioxidants as evidenced by decreased levels of HIF-1α and TAC at before- compared to after-dialysis levels.

Hepatic ischemic preconditioning provides protection against distant renal ischemia and reperfusion injury in mice

We previously demonstrated that there are acute and delayed phases of renal protection against renal ischemia and reperfusion (IR) injury with renal ischemic preconditioning (IPC). This study assessed whether hepatic IPC could also reduce distant renal IR injury through the blood stream-mediated supply of reactive oxygen species (ROS). Male C57BL/6 mice were randomly divided into four groups: group I, sham operated including right nephrectomy; group II (IR), left renal ischemia for 30 min and reperfusion injury; group III (IPC-IR), hepatic ischemia for 10 min followed by 10 min of reperfusion before left renal IR injury; group IV (MPG - IPC + IR), pretreated with 100 mg/kg N-(2-mercaptopropionyl)-glycine (MPG) 15 min before hepatic IPC and left renal IR injury. Renal function, histopathologic findings, proinflammatory cytokines, and cytoprotective proteins were evaluated 15 min or 24 hr after reperfusion. Hepatic IPC attenuated the expression of proinflammatory cytokines, tumor necrosis factor α, intercellular adhesion molecule 1, and induced inducible nitric-oxide synthase, and the phosphorylation of Akt in the murine kidney. Renal function was better preserved in mice with hepatic IPC (group III) than groups II or IV. Hepatic IPC protects against distant renal IR injury through the blood stream-delivery of hepatic IPC-induced ROS, by inducing cytoprotective proteins, and by inhibiting inflammatory reactions.

Prognostic factors and a prognostic index for cats with acute kidney injury

BACKGROUND

The clinical manifestations of acute kidney injury (AKI) range from mild to fatal in cats; however, prognosis factors have been rarely studied.

HYPOTHESIS/OBJECTIVES

To find the clinical factors significantly correlated with the outcome among cats with AKI and to develop a simple prognostic index.

ANIMALS

Seventy cats with AKI were recruited.

METHODS

Demographic and clinicopathological data obtained from 70 cats with AKI were retrospectively collected. Student's t-test or Mann-Whitney U-test and Pearson chi-square test or Fisher's exact were applied to determine the factors associated with survival in cats with AKI. Using logistic regression, the statistically significant factors associated with prognosis were identified and a new prediction model was generated.

RESULTS

The overall case fatality rate was 64% (45/70). The results showed that nonsurviving cats had significantly lower levels of PCV, WBC, RBC, LDH and albumin, a lower albumin/globulin ratio, lower blood glucose, and a reduced body temperature, as well as being older. Serum urea and creatinine concentrations were not statistically significant as prognostic factors, but a decrease in these 2 variables in 3 days was significantly related to a reduction in death. A summary prognostic index including body temperature and LDH and albumin concentrations had area under the receiver-operating characteristic curve (AUROC) for predicting death of 0.86 (P < .05) and a cut-off value of 0.82, a sensitivity of 77% and a specificity of 90%.

CONCLUSIONS

The prognosis in cats with AKI is quite different from that found for human and dogs.

Chronic kidney disease and risk for presenting with acute myocardial infarction versus stable exertional angina in adults with coronary heart disease

OBJECTIVES

The aim of this study was to examine whether kidney dysfunction is associated with the type of clinical presentation of coronary heart disease (CHD).

BACKGROUND

Reduced kidney function increases the risk for developing CHD, but it is not known whether it also influences the acuity of clinical presentation, which has important prognostic implications.

METHODS

A case-control study was conducted of subjects whose first clinical presentation of CHD was either acute myocardial infarction or stable exertional angina between October 2001 and December 2003. Estimated glomerular filtration rate (eGFR) before the incident event was calculated using calibrated serum creatinine and the abbreviated MDRD (Modification of Diet in Renal Disease) equation. Patient characteristics and use of medications were ascertained from self-report and health plan databases. Multivariable logistic regression was used to examine the association of reduced eGFR and CHD presentation.

RESULTS

A total of 803 adults with incident acute myocardial infarctions and 419 adults with incident stable exertional angina who had baseline eGFRs ≤130 ml/min/1.73 m(2) were studied. Mean eGFR was lower in subjects with acute myocardial infarctions compared with those with stable angina. Compared with eGFR of 90 to 130 ml/min/1.73 m(2), a strong, graded, independent association was found between reduced eGFR and presenting with acute myocardial infarction, with adjusted odds ratios of 1.36 (95% confidence interval: 0.99 to 1.86) for eGFR 60 to 89 ml/min/1.73 m(2), 1.55 (95% confidence interval: 0.92 to 2.62) for eGFR 45 to 59 ml/min/1.73 m(2), and 3.82 (95% confidence interval: 1.55 to 9.46) for eGFR <45 ml/min/1.73 m(2) (p < 0.001 for trend).

CONCLUSIONS

An eGFR <45 ml/min/1.73 m(2) is a strong, independent predictor of presenting with acute myocardial infarction versus stable angina as the initial manifestation of CHD.

HDL-associated enzymes and proteins in hemodialysis patients

OBJECTIVES

To evaluate HDL-associated proteins and enzymes and their relation with lipoprotein profile and inflammatory markers in chronic renal patients on hemodialysis.

DESIGN AND METHODS

We studied 53 patients under hemodialysis and 32 healthy subjects as controls. We compared plasma lipids, Apoprotein-AI and hs-CRP, as a marker of chronic inflammation. We evaluated proteins and enzymes associated to HDL, involved in several points of lipoprotein metabolism: CETP, paraoxonase and LpPLA2 activities. Hepatic lipase was measured in postheparin plasma.

RESULTS

Patients showed higher triglycerides and lower LDL-, HDL- and total-cholesterol than controls (p<0.05). Also, in comparison with controls, Apoprotein-AI, paraoxonase and hepatic lipase were lower, while CETP was higher (p<0.03). LpPLA2 did not show changes between groups.

CONCLUSION

Beyond plasma lipid-lipoprotein profile, other factors could contribute to induce a pro-oxidative and pro-inflammatory status. The protective role of HDL does not only depend on its concentration, but also on its functionality.

IL-6 levels, nutritional status, and mortality in prevalent hemodialysis patients

BACKGROUND AND OBJECTIVES

The influence of serum IL-6 levels on nutritional status in chronic hemodialysis (HD) patients remains to be elucidated. The present report describes a prospective longitudinal study of IL-6 levels and nutritional parameters to determine whether high IL-6 levels are independently associated with nutritional status over time in a cohort of prevalent hemodialysis patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

85 clinically stable hemodialysis patients (37.6% women), with a mean age of 66.5 ± 10.6 years, were studied after exclusion of patients with BMI < 20 kg/m(2) and/or serum albumin <35 g/L. IL-6, dietary energy and protein intake, and biochemical markers of nutrition and body composition (anthropometry and bioimpedance analysis) were measured at baseline and at 6, 12, 18, and 24 months following enrollment. Observation of this cohort was continued over 2 additional years.

RESULTS

IL-6 levels increased with time in both unadjusted (linear estimate: 2.57 ± 0.44 pg/ml per 2 yrs; P = 0.001) and adjusted models (linear estimate: 2.35 ± 0.57 pg/ml per 2 yrs; P = 0.049). Significant reductions of daily energy intake, laboratory markers (albumin, transferrin, cholesterol, creatinine), and body composition (fat mass) with higher IL-6 levels were observed over the duration of the longitudinal observation period. However, none of the studied parameters were associated with changes in IL-6 levels over time (IL-6-by-time interactions were NS). Furthermore, cumulative incidences of survival were correlated with the baseline serum IL-6 levels (P = 0.004 by log-rank test). Finally, for each pg/ml increase in IL-6 level, the hazard ratio for death from all causes was 1.06 (95% CI 1.01 to 1.10) after adjustment for demographic and clinical parameters.

CONCLUSIONS

Our results suggest that higher serum IL-6 levels are associated with all-cause mortality without additional changes in clinical and laboratory markers of nutritional status in clinically stable HD patients.

Detection of iron deposition in dermal fibrocytes is a useful tool for histologic diagnosis of nephrogenic systemic fibrosis

Nephrogenic systemic fibrosis (NSF) is a fibrotic disease that presents with a history of renal dysfunction. The differential diagnosis generally includes scleromyxedema, systemic sclerosis, and morphea. Especially, scleromyxedema can be extremely difficult to distinguish microscopically. Although the fibrocytes in NSF are often positive for CD34 and procollagen-I, this is not specific for NSF. We identified positive iron staining in the skin of a patient with NSF and investigated whether this was a specific feature among 9 patients with NSF reported in Japan. We found that 6 of 9 patients showed positive iron staining in the dermal fibrocytes. The amount of iron deposition seemed to have no correlation with the degree of fibrosis or duration of the skin lesions but correlated with apparent history of the use of gadolinium-based contrast agents. As controls, skin biopsies from patients with scleromyxedema, morphea, and systemic sclerosis were evaluated by iron staining. None of these control patients showed iron deposition, indicating that positive iron staining may be specific to NSF and can be a useful tool for NSF diagnosis.

Effect of pretransplant dialysis modality and duration on long-term outcomes of children receiving renal transplants

BACKGROUND

Adults receiving preemptive renal transplants have better allograft survival. Our study investigated differences in graft and patient survival based on need for, and duration of, pretransplant dialysis in pediatric renal transplant recipients.

METHODS

Data on pediatric kidney transplants from January 1995 to December 2000 from the Organ Procurement and Transplantation Network were included. Multivariable Cox proportional hazards analysis was performed to determine the effect of pretransplant dialysis on graft and patient survival.

RESULTS

Of 3606 transplants, 28% were preemptive, 38% followed pretransplant hemodialysis (HD), and 34% peritoneal dialysis (PD). The 1-year acute rejection rate was lowest for the preemptive group (36%) compared with the HD (45.5%; P=0.0002) and PD (44.2%; P=0.0008) groups. On multivariable analysis, an increased relative risk of graft failure was seen with, among other variables, deceased donor transplantation and acute rejection within the first year, but not with pretransplant dialysis. When analyzed separately by donor source, pretransplant dialysis had no effect on graft survival for deceased donor graft recipients, whereas for living donor recipients, the use and duration of pretransplant HD adversely affected pediatric renal graft survival in a linear manner. No such effect was seen with pretransplant PD.

CONCLUSIONS

There is a linear increase in the risk of graft failure with the use of and increasing duration of pretransplant HD for living donor grafts. This indicates another reason to minimize the need for and duration of pretransplant HD in children with chronic kidney disease.

Upregulation of surrogate markers of inflammation and thrombogenesis in patients with ESRD: pathophysiologic and therapeutic implications

Patients with end-stage renal disease (ESRD) undergoing regular hemodialysis have high annual mortality rate of around 15%. The most predominant cause of death is cardiovascular, which is not entirely explainable with conventional cardiac risk factors present in these patients. It has been postulated that ESRD is a chronic inflammatory and hypercoagulable condition with marked elevation of several markers that may explain this high mortality. In the current study, patients with ESRD on a stable regimen of hemodialysis were studied for the inflammatory and thrombogenesis markers to explain this phenomenon. The parameters studied were of thrombogenesis-thrombin-antithrombin III complex (TAT), prothrombin fragment (F1.2), D-dimer, and fibrinopeptide A (FPA) and inflammation-CD40 ligand, myeloperoxidase (MPO), tumor necrosis factor α (TNF-α), monocyte chemotactic protein-1 (MCP-1), and nitric oxide (NO), and compared to control group comprised of 100 healthy volunteers. Our study shows that ESRD patients exhibit activation of the coagulation and inflammatory processes.

Impact of proteinuria and glomerular filtration rate on risk of thromboembolism in atrial fibrillation: the anticoagulation and risk factors in atrial fibrillation (ATRIA) study

BACKGROUND

Atrial fibrillation (AF) substantially increases the risk of ischemic stroke, but this risk varies among individual patients with AF. Existing risk stratification schemes have limited predictive ability. Chronic kidney disease is a major cardiovascular risk factor, but whether it independently increases the risk for ischemic stroke in persons with AF is unknown.

METHODS AND RESULTS

We examined how chronic kidney disease (reduced glomerular filtration rate or proteinuria) affects the risk of thromboembolism off anticoagulation in patients with AF. We estimated glomerular filtration rate using the Modification of Diet in Renal Disease equation and proteinuria from urine dipstick results found in laboratory databases. Patient characteristics, warfarin use, and thromboembolic events were ascertained from clinical databases, with validation of thromboembolism by chart review. During 33,165 person-years off anticoagulation among 10,908 patients with AF, we observed 676 incident thromboembolic events. After adjustment for known risk factors for stroke and other confounders, proteinuria increased the risk of thromboembolism by 54% (relative risk, 1.54; 95% CI, 1.29 to 1.85), and there was a graded, increased risk of stroke associated with a progressively lower level of estimated glomerular filtration rate compared with a rate > or =60 mL x min(-1) x 1.73 m(-2): relative risk of 1.16 (95% CI, 0.95 to 1.40) for estimated glomerular filtration rate of 45 to 59 mL x min(-1) x 1.73 m(-2) and 1.39 (95% CI, 1.13 to 1.71) for estimated glomerular filtration rate <45 mL x min(-1) x 1.73 m(-2) (P=0.0082 for trend).

CONCLUSIONS

Chronic kidney disease increases the risk of thromboembolism in AF independently of other risk factors. Knowing the level of kidney function and the presence of proteinuria may improve risk stratification for decision making about the use of antithrombotic therapy for stroke prevention in AF.

Oxidative stress in children on hemodialysis: value of autoantibodies against oxidized low-density lipoprotein

The principal causes of morbidity and mortality in children with chronic renal failure on maintenance hemodialysis are cardiovascular complications. Recently, it has been suggested that oxidative stress, chronic inflammation and malnutrition are risk factors for cardiovascular disease. However, to date, biomarkers of oxidative stress have not been well studied in children. The aim of this study was to investigate the relationship between oxidative stress and cardiovascular risk factors in children on hemodialysis therapy. Twenty-eight hemodialysis patients (13 females, 15 males; mean age 15.1 +/- 2.5 years) and 20 healthy children (13 females, seven males; mean age 14.3 +/- 2.7 years) were included in the study. Levels of antibodies to oxidized low-density lipoprotein (oLABs), high sensitivity C-reactive protein (hs-CRP), albumin, prealbumin, transferrin, and ferritin were measured. Antibodies to oxidized low-density lipoprotein (LDL) in hemodialysis patients were lower than those in the controls (P < 0.05). The patients with lower oLAB titers had higher levels of hs-CRP and ratio of erythropoietin to hematocrit (EPO/Htc), and lower levels of albumin, prealbumin, apolipoprotein A-1 (ApoA(1)), and high-density lipoprotein (P < 0.05). Antibodies to oxidized LDL in hemodialysis patients with dyslipidemia were lower than those of patients with normal lipid profile (P < 0,05). This study showed that children treated by hemodialysis are exposed to oxidative stress and chronic inflammation. We suggest that oLAB levels are decreased in children on hemodialysis as a result of severe oxidative stress and that these antibodies are related to inflammation, anemia, malnutrition and dyslipidemia.

Glucose in the dialysate: historical perspective and possible implications?

Hemodialysate solutions often contain high concentrations of glucose (up to 200 mg/dL). The historical reasons for the addition of glucose to the dialysate included: (1) aid in performance of ultrafiltration and (2) minimization of nutritional (caloric) losses during dialysis. However, recent experimental evidence supports the fact that exposure to high levels of glucose may be pro-inflammatory. Given the high morbidity and mortality associated with dialysis and its linkage to chronic inflammation, the routine use of glucose in the dialysate may warrant reexamination. This review examines the utility of glucose in the dialysate and discusses the potential implications on chronic inflammation in patients with end-stage renal disease. While there is currently no evidence for a casual relationship between dialysate glucose concentration and the chronic inflammation seen in ESRD, this possibility is explored.

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.

Infections in patients with chronic kidney disease

There has been a notable lack of research activity regarding major infections in patients with advanced chronic kidney disease. To an outsider, this might seem unexpected, because uremia has long been considered a state of immune hyporesponsiveness and rates of major bacterial infection, like septicemia and pneumonia, are known to be orders of magnitude more likely in dialysis populations than in the general population. This article reviews recent literature on the topic, focusing predominantly on the clinical epidemiology of major bacterial infections in dialysis patients, the links between bacterial infections and cardiovascular disease, and randomized trials of interventions designed to prevent these infections.

Erythropoiesis-stimulating agent hyporesponsiveness

Approximately 5-10% of patients with chronic kidney disease demonstrate hyporesponsiveness to erythropoiesis-stimulating agents (ESA), defined as a continued need for greater than 300 IU/kg per week erythropoietin or 1.5 mug/kg per week darbepoetin administered by the subcutaneous route. Such hyporesponsiveness contributes significantly to morbidity, mortality and health-care economic burden in chronic kidney disease and represents an important diagnostic and management challenge. The commonest causes of ESA resistance are non-compliance, absolute or functional iron deficiency and inflammation. It is widely accepted that maintaining adequate iron stores, ideally by administering iron parenterally, is the most important strategy for reducing the requirements for, and enhancing the efficacy of ESA. There have been recent epidemiologic studies linking parenteral iron therapy to an increased risk of infection and atherosclerosis, although other investigations have refuted this. Inflammatory ESA hyporesponsiveness has been reported to be improved by a number of interventions, including the use of biocompatible membranes, ultrapure dialysate, transplant nephrectomy, ascorbic acid therapy, vitamin E supplementation, statins and oxpentifylline administration. Other variably well-established causes of ESA hyporesponsiveness include inadequate dialysis, hyperparathyroidism, nutrient deficiencies (vitamin B12, folate, vitamin C, carnitine), angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, aluminium overload, antibody-mediated pure red cell aplasia, primary bone marrow disorders, myelosuppressive agents, haemoglobinopathies, haemolysis and hypersplenism. This paper reviews the causes of ESA hyporesponsiveness and the clinical evidence for proposed therapeutic interventions. A practical algorithm for approaching the investigation and management of patients with ESA hyporesponsiveness is also provided.

New insights into nephrogenic systemic fibrosis

Nephrogenic systemic fibrosis is a new disorder reported almost exclusively in patients who have renal insufficiency and are exposed to contrast media formulated with gadolinium. High morbidity and mortality are associated with this severely disabling and painful condition. The acute phase begins upon exposure to gadolinium contrast media, characterized by a systemic inflammatory response involving iron mobilization, and then as a progressive, chronic phase in which fibrosis develops. Proposed is a unifying model of cumulative risk factors in which the interplay of systemic inflammation and stimulated hematopoietic environment associated with hyperparathyroidism and erythropoietin may tie to a common pathogenic mechanism of fibrogenesis. Because there are no uniformly effective interventions to treat nephrogenic systemic fibrosis other than successful renal transplantation, prevention by avoiding gadolinium contrast media in patients with chronic kidney disease is vital. On the basis of suspected pathogenesis, it is also reasonable to limit erythropoietin and iron therapy to dosages ensuring recommended targets and adequately control hyperparathyroidism. Herein is reviewed what is currently known about this subject.

Obese sarcopenia in patients with end-stage renal disease is associated with inflammation and increased mortality

BACKGROUND

Adipose tissue in overweight patients with end-stage renal disease (ESRD) is a source of proinflammatory mediators, which could contribute to protein-energy wasting (PEW), cardiovascular disease, and increased mortality. Overweight in ESRD patients, however, is reported to be associated with better survival.

OBJECTIVE

We investigated the associations between overweight [body mass index (BMI; in kg/m2) > 25], inflammation, PEW, and mortality in ESRD patients starting dialysis.

DESIGN

In 328 ESRD patients (age: 53 +/- 12 y; 201 men), inflammatory biomarkers, nutritional status, and dual-energy X-ray absorptiometry data were analyzed close to the start of treatment. We compared clinical and laboratory data in patients in 3 BMI groups, with and without PEW.

RESULTS

The prevalence of PEW was high in patients in all 3 BMI groups. PEW was associated with both high fat body mass index (FBMI) and low lean body mass index (LBMI). Both PEW and high BMI were associated with inflammation. The highest concentrations of inflammatory mediators and the highest FBMI were seen in overweight patients with PEW. BMI as such did not predict clinical outcome; however, for each BMI group, the presence of PEW was associated with increased mortality. With BMI 20-25 as the reference group, BMI < 20 did not predict mortality, overweight (BMI > 25) was associated with a survival advantage, and low FBMI was found to be an independent predictor of mortality.

CONCLUSIONS

PEW is common in overweight ESRD patients and is associated with high FBMI, low LBMI, and inflammation. PEW was a predictor of mortality in both obese and nonobese sarcopenia patients. BMI as such, however, was a poor predictor of mortality, but after adjustment for various confounders, including PEW, a high BMI and a high FBMI were associated with survival advantage.

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.

Cell Therapy in Kidney Disease: Cautious Optimism … But Optimism Nonetheless

The recently discovered therapeutic potential of stem or progenitor cells has initiated development of novel treatments in a number of diseases—treatments that could not only improve patients’ quality of life, but also halt or even prevent disease progression. Hypertension; fluctuations in glycemia, electrolytes, nutrient levels, and circulating volume; and frequent infections and the associated inflammation all greatly impair the endothelium in patients undergoing peritoneal dialysis. As our understanding of the regulatory function of the endothelium advances, focus is increasingly being placed on endothelial repair in acute and chronic renal failure and after renal transplantation. The potential of progenitor cells to repair damaged endothelium and to reduce inflammation in patients with renal failure remains unexamined; however, a successful cell therapy could reduce morbidity and mortality in kidney disease.

Important contributions have been made in identifying progenitor cell populations in the kidney, and further investigations into the relationships of these cells with the pathophysiology of the disease are underway. As the kidney disease field prepares for the first human trials of progenitor cell therapies, we deemed it important to review representative original research, and to share our perspectives and lessons learned from clinical trials of progenitor cell–based therapies that have commenced in patients with cardiovascular disease.

Endothelial function predicts the development of renal damage after combined nephrectomy and myocardial infarction

It was demonstrated that individual renal endothelial dilatory function of the healthy rat predicts susceptibility to subsequent renal damage induced by 5/6 nephrectomy. In addition, it is reported that myocardial infarction (MI) that was performed upon unilateral nephrectomy (UNx) induced highly variable renal damage. Therefore, whether the variability in renal damage after MI could be explained by the variation in individual renal endothelial function before the induction of injury was studied. Endothelium-dependent relaxation to acetylcholine was investigated in vitro in small arteries that were isolated from the extirpated kidney at UNx. MI was induced 1 wk after UNx by ligation of the left coronary artery. Proteinuria and systolic BP were evaluated weekly for 16 wk thereafter using metabolic cages and the tail-cuff method, respectively. Upon termination of the study, focal glomerulosclerosis was evaluated by histology as an additional marker of renal damage. After MI, nephrectomized male Wistar rats (n = 15) gradually developed variable proteinuria, ranging from 20 to 507 mg/24 h at week 16, with an average systolic BP of 131 +/- 7 mmHg. The individual renal endothelial function of the healthy rats predicted the extent of renal damage in terms of proteinuria (r = -0.62, P = 0.008) and focal glomerulosclerosis (r = -0.70, P = 0.003). The individual level of renal endothelial function in the healthy rat is able to predict the severity of renal damage that is induced by MI. Further exploration of the underlying mechanisms may lead to discovery of preventive renoprotective therapies.

Ischemic preconditioning provides both acute and delayed protection against renal ischemia and reperfusion injury in mice

Acute as well as delayed ischemic preconditioning (IPC) provides protection against cardiac and neuronal ischemia reperfusion (IR) injury. This study determined whether delayed preconditioning occurs in the kidney and further elucidated the mechanisms of renal IPC in mice. Mice were subjected to IPC (four cycles of 5 min of ischemia and reperfusion) and then to 30 min of renal ischemia either 15 min (acute IPC) or 24 h (delayed IPC) later. Both acute and delayed renal IPC provided powerful protection against renal IR injury. Inhibition of Akt but not extracellular signal-regulated kinase phosphorylation prevented the protection that was afforded by acute IPC. Neither extracellular signal-regulated kinase nor Akt inhibition prevented protection that was afforded by delayed renal IPC. Pretreatment with an antioxidant, N-(2-mercaptopropionyl)-glycine, to scavenge free radicals prevented the protection that was provided by acute but not delayed renal IPC. Inhibition of protein kinase C or pertussis toxin-sensitive G-proteins attenuated protection from both acute and delayed renal IPC. Delayed renal IPC increased inducible nitric oxide synthase (iNOS) as well as heat-shock protein 27 synthesis, and the renal protective effects of delayed preconditioning were attenuated by a selective inhibitor of iNOS (l-N(6)[1-iminoethyl]lysine). Moreover, delayed IPC was not observed in iNOS knockout mice. Both acute and delayed IPC were independent of A(1) adenosine receptors (AR) as a selective A(1)AR antagonist failed to block preconditioning and acute and delayed preconditioning occurred in mice that lacked A(1)AR. Therefore, this study demonstrated that acute or delayed IPC provides renal protection against IR injury in mice but involves distinct signaling pathways.

Patients receiving maintenance dialysis have more severe functionally significant skeletal muscle wasting than patients with dialysis-independent chronic kidney disease

BACKGROUND

Chronic renal replacement therapy patients exhibit reduction in skeletal muscle function as a result of a combination of metabolic effects and muscle fibre size reduction. The aim of this study was to compare muscle mass with function in patients with chronic kidney disease (CKD) at stages 4 and 5 on haemodialysis (HD) and peritoneal dialysis (PD), and investigate the associations of muscle wasting in a cross-sectional cohort.

METHODS

We studied 134 patients (60 HD, 28 PD and 46 CKD 4). The three groups were well matched for age, sex, diabetes and dialysis vintage. Cross-sectional area (CSA) of muscle and fat was measured from a standardized multi-slice CT scan of a 6 cm long section of thigh. CSA of soft tissue was taken from appropriate fat and muscle densities. Functional assessment was by the sit-to-stand 60 test, assessing both the number of sit-to-stands possible under controlled conditions in 60 s (STS 60), and the time taken to perform five sit-to-stand movements (STS 5). Data were collected on a wide range of potential determinants of muscle CSA.

RESULTS

There were no significant differences in haemoglobin between males or females or between any of the groups studied. Serum phosphate and calcium-phosphate product were higher in HD patients as compared to CKD4 patients, but there were no differences in these variables when comparing PD patients with either CKD4 or HD patients. Muscle CSA correlated well with objective functional assessments in males (STS 60 R = 0.52, P<0.0001) and females (R = 0.41, P = 0.004), and STS performance was reduced in dialysed patients as compared with CKD 4. Univariate analysis demonstrated that muscle CSA was associated with serum albumin concentration (R = 0.49, P<0.0001), age (R = -0.35, P = 0.005) and C-reactive protein (R = -0.34, P = 0.004). Creatinine clearance, dialysis adequacy, dialysis vintage and time-averaged serum bicarbonate, calcium and phosphate concentrations were not correlated with muscle CSA.

CONCLUSION

In conclusion, patients with dialysis-treated CKD 5 exhibited more functionally significant muscle wasting than patients with CKD 4. This may be amenable to modification with targeted exercise or amelioration of factors associated with observed differences in muscle mass.

Silent Cerebral White Matter Lesions and Their Relationship With Vascular Risk Factors in Middle-Aged Predialysis Patients With CKD

BACKGROUND

Silent cerebral white matter lesions are observed on magnetic resonance imaging (MRI) scans in elderly people, and they are related to vascular risk factors, particularly hypertension. No data on the prevalence and risk factors of white matter lesions in patients with chronic kidney disease (CKD) are available. The aim is to analyze the prevalence of white matter lesions and their determinants in this population.

METHODS

We studied 52 patients without diabetes with CKD (stage 3 or 4) aged 30 to 60 years (average, 49 years) and a group of 32 normotensive control subjects. MRI studies were performed and subcortical and periventricular white matter lesions were evaluated by using semiquantitative measures. Patients were classified into 2 groups depending on the presence or absence of white matter lesions. Echocardiographic studies and measures of markers of systemic inflammation (C-reactive protein and interleukin 6) also were performed.

RESULTS

White matter lesions were more prevalent in patients with CKD than controls (33% versus 6%; P = 0.008). Patients with CKD who had white matter lesions were older; had a greater history of cardiovascular disease and vascular nephropathy as a primary cause of renal disease and greater levels of systolic blood pressure, pulse pressure, left ventricular mass index, and C-reactive protein; and were administered more antihypertensive drugs than patients with CKD without white matter lesions. Stage and duration of CKD were not related to the presence of white matter lesions. After adjusting for several factors, only vascular nephropathy (odds ratio, 15.6; 95% confidence interval, 1.27 to 191.54; P = 0.03) independently predicted an increased risk for white matter lesions.

CONCLUSION

One third of middle-aged patients with CKD have silent cerebral white matter lesions. Vascular nephropathy seems to be the most important factor related to the presence of these lesions, suggesting that white matter lesions reflect ischemic brain damage caused by generalized vascular damage.

Prealbumin, mortality, and cause-specific hospitalization in hemodialysis patients

BACKGROUND

Prealbumin (transthyretin) is a hepatic secretory protein thought to be important in the evaluation of nutritional deficiency and nutrition support. Prior studies have suggested that the serum prealbumin concentration is independently associated with mortality in hemodialysis patients, even with adjustment for serum albumin and other nutritional parameters.

METHODS

To determine whether prealbumin was independently associated with mortality and morbidity (cause-specific hospitalization) in hemodialysis patients, we analyzed data on 7815 hemodialysis patients with at least one determination of serum prealbumin during the last three months of 1997. Unadjusted, case mix-adjusted, and multivariable-adjusted relative risks of death were calculated for categories of serum prealbumin using proportional hazards regression. We also determined whether the prealbumin concentration was associated with all-cause, cardiovascular, infection-related, and vascular access-related hospitalization.

RESULTS

The relative risk (RR) of death was inversely related to the serum prealbumin concentration. Relative to prealbumin > or =40 mg/dL, the adjusted RRs of death were 2.41, 1.85, 1.49, and 1.23 for prealbumin <15, 15-20, 20-25, and 25-30 mg/dL, respectively. The adjusted RRs of hospitalization due to infection were 2.97, 1.95, 1.81, and 1.61 for prealbumin <15, 15-20, 20-25, and 25-30 mg/dL, respectively. The adjusted RRs of vascular access-related hospitalization were 0.48, 0.52, 0.58, and 0.71 for prealbumin <15, 15-20, 20-25, and 25-30 mg/dL, respectively. While serum albumin was strongly associated with mortality and all-cause hospitalization, it was not associated with hospitalization due to infection, and lower levels were associated with higher rather than lower rates of vascular access-related hospitalization.

CONCLUSION

In hemodialysis patients, lower prealbumin concentrations were associated with mortality and hospitalization due to infection, independent of serum albumin and other clinical characteristics. Higher prealbumin concentrations were associated with vascular access-related hospitalization. In light of these findings, more intensive study into the determinants and biological actions of prealbumin (transthyretin) in end-stage renal disease is warranted.

Relationship between chronic inflammation and cardiovascular risk factors in children on maintenance hemodialysis

Cardiovascular disease is one of the most important causes of morbidity and mortality in children with end-stage renal failure. Chronic inflammation and malnutrition have been suggested to be risk factors for cardiovascular disease. However, to date, biomarkers of inflammation have not been well studied in children. The aim of this study was to investigate the relation between chronic inflammation and cardiovascular risk factors in children on hemodialysis therapy. Twenty-seven patients on hemodialysis (14 girls, 13 boys) of mean age 15.3 +/- 2.4 years and 20 healthy children (13 girls, 7 boys) of mean age 14.3 +/- 2.7 years were included the study. C-reactive protein (CRP), albumin, prealbumin, transferrin, ferritin, and fibrinogen were measured as the markers of inflammation. The levels of CRP, ferritin, and erythrocyte sedimentation rate among hemodialysis patients were significantly higher than those of control subjects (P < .001 for all). Albumin and transferrin levels were found to be lower than those of control group (P = .02 and P < .001, respectively). CRP levels were negatively correlated with albumin, prealbumin, apoprotein A1, HDL, and hemoglobin levels, and positively correlated with erythropoietin/Htc ratios. This study suggests that hemodialyzed children are exposed to chronic inflammation. In addition, CRP may be an indicator of chronic inflammation related to cardiovascular risk factors, such as malnutrition, dyslipidemia, and anemia. In conclusion, we suggest that the risk of cardiovascular disease could be reduced by defining markers of chronic inflammation and malnutrition in hemodialyzed children and by taking necessary measures at an early stage.

Overproduction of reactive oxygen species in end-stage renal disease patients: a potential component of hemodialysis-associated inflammation

During the past decade, hemodialysis (HD)-induced inflammation has been linked to the development of long-term morbidity in end-stage renal disease (ESRD) patients on regular renal replacement therapy. Because interleukins and anaphylatoxins produced during HD sessions are potent activators for nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, an example of an enzyme that is responsible for overproduction of reactive oxygen species (ROS), this may constitute a link between leukocyte activation and cell or organ toxicity. Oxidative stress, which results from an imbalance between oxidant production and antioxidant defense mechanisms, has been documented in ESRD patients using lipid and/or protein oxidative markers. Characterization of HD-induced oxidative stress has included identification of potential activators for NADPH oxidase. Uremia per se could prime phagocyte oxidative burst. HD, far from improving the oxidative status, results in an enhancement of ROS owing to hemoincompatibility of the dialysis system, hemoreactivity of the membrane, and trace amounts of endotoxins in the dialysate. In addition, the HD process is associated with an impairment in antioxidant mechanisms. The resulting oxidative stress has been implicated in long-term complications including anemia, amyloidosis, accelerated atherosclerosis, and malnutrition. Prevention of oxidative stress in HD might focus on improving the hemocompatibility of the dialysis system, supplementation of deficient patients with antioxidants, and modulation of NADPH oxidase by pharmacologic approaches.

Predictive value of pretransplant inflammatory markers in renal allograft survival and rejection in children

Pretransplant (pre-Tx) inflammation has been associated with acute rejection (AR) in adult Tx recipients. Our study was performed to determine whether a single pre-Tx serum C-reactive protein (CRP), Neopterin (Neo), and IL-12 determination could predict outcome in pediatric renal Tx recipients. Pre-Tx sera from 51 children transplanted between 1985 and 2000 were analyzed for serum CRP, Neo, and IL-12 for correlation with Tx-related variables. Endpoints were graft loss and AR. Kaplan-Meier and log-rank statistics were used to compare rejection-free and overall graft survival at different quartiles for each marker. Cox regression analysis was performed to determine the independent effects of various pre-Tx variables on the endpoints. The mean age of the children at Tx was 11 years. The mean CRP, Neo, and IL-12 were 1.3 mg/L, 1.78 ng/mL and 123 pg/mL, respectively. At last-follow-up (mean 4.9 years after Tx), 50% of the children had experienced AR and 29% had lost their grafts. The mean CRP, Neo, and IL-12 were not different between the patients with versus without AR or graft loss (P > .4 for all). Neither rejection-free survival nor graft survival was affected by CRP, Neo, or IL-12 quartiles (log-rank test). Cox regression analysis demonstrated no predictive value of any marker on the outcomes. Unlike adults, a single pre-Tx determination of inflammatory markers was not predictive of AR or graft loss in children. The pathogenesis of AR may be different in children with a lesser contribution of alloantigen-independent factors such as chronic infections.

Assessment of pretransplant inflammation in pediatric renal allograft recipients

Pretransplant (Tx) inflammation is linked to adverse outcomes in adult Tx recipients but no such data exist for children. Our study evaluated the predictive value of three pre-Tx inflammatory markers: serum C-reactive protein (CRP), Neopterin (Neo) and interleukin (IL) 12, in determining outcome. Pre-Tx serum on 51 children (mean age 11 years) transplanted between 1985 and 2000 was analyzed. Data on other variables were abstracted from patient records. Primary end-points were graft survival and acute rejection (AR). Kaplan-Meier and log-rank statistics compared endpoints in patients at different quartiles for each marker. Cox regression analysis was used to determine the independent effect of the markers on the end-points. The mean CRP, Neo, and IL-12 were 1.3 mg/l, 1.78 ng/ml, and 123 pg/ml, respectively. The mean CRP, Neo, and IL-12 were not different between the patients with and without AR or graft loss (P > 0.4 for all). Neither rejection-free survival nor graft survival was affected by CRP, Neo, or IL-12 quartiles. Cox-regression analysis demonstrated no predictive value of any marker on outcome. Unlike adults, a single pre-Tx determination of inflammatory markers was not predictive of AR or graft loss in children, indicating that the pathogenesis of AR may be different in children.

Vascular Access in Hemodialysis: Issues, Management, and Emerging Concepts

This article (1) identifies the types of hemodialysis access, (2) summarizes the clinical standard of care for dialysis access grafts and fistulae, (3) describes the pathology and pathogenesis of venous stenosis in dialysis access grafts and fistulae, (4) tabulates avail-able therapies for hemodialysis vascular access dysfunction and speculates on the rea-sons for the lack of effective therapies, and (5) discusses the development and application of novel therapeutic interventions for this difficult clinical problem. The possibility that dialysis access grafts and fistulae could be the ideal clinical model for testing novel local therapies to block neointimal hyperplasia is discussed.

Megestrol Acetate in a Moderate Dose for the Treatment of Malnutrition-Inflammation Complex in Maintenance Dialysis Patients

BACKGROUND

Malnutrition-inflammation complex syndrome and anorexia, common conditions in maintenance dialysis patients, are strongly associated with higher mortality and hospitalization and lower quality of life (QoL) in this population. Megestrol acetate, 800 mg/day, has been shown to increase appetite and food intake and to mitigate inflammation in cachectic AIDS and cancer patients, leading to weight gain, but it is also associated with side effects at this dose.

METHODS

We evaluated the efficacy of the oral solution of megestrol acetate in half of its conventional dose in improving the nutritional state and inflammation in 10 hypoalbuminemic dialysis patients (albumin < 3.7 g/dL). Six women and 4 men, ages 60.2 years, took 400 mg of megestrol acetate solution daily for 16 weeks. Anthropometry, dual energy x-ray absorptiometry, 24-hour diet recalls, and biochemical measurements of nutrition and inflammation, including serum C-reactive protein and leptin, were performed.

RESULTS

At the end of the 16 weeks of intervention, weight and body mass index increased by 9%, body fat proportion by 31%, and triceps skinfold by 40% (P < .01). Serum albumin increased from 3.0 to 3.3 g/dL and continued to increase significantly to 3.6 g/dL after 3 months postintervention (P = .03). Serum leptin increased from 5.2 to 10.7 ng/mL (P = .09). Daily protein and energy intake increased progressively up to 27% to 42% by the end of the trial (P < or = .01). In 8 patients without acute infection, serum C-reactive protein declined from 1.24 to 0.78 mg/L (P = .06). QoL and appetite were reported to be improved. No major side effects were observed, and all 10 patients completed the 16 weeks of daily intake of megestrol acetate without interruption.

CONCLUSIONS

Megestrol acetate oral solution in half of its conventional dose is safe and improves the nutritional state, inflammation, and anorexia in maintenance dialysis patients. Larger-scale placebo-controlled randomized studies are needed to confirm the beneficial effects of 400 mg/day of megestrol acetate in dialysis patients.