Inflammation as a cause of malnutrition, atherosclerotic cardiovascular disease, and poor outcome in hemodialysis patients

Dietary acid load and markers of malnutrition, inflammation, and oxidative stress in hemodialysis patients

Aims

The present study was conducted to examine the association between dietary acid load (DAL) and markers of inflammation, oxidative stress, and malnutrition in a group of Iranian hemodialysis (HD) patients.

Methods

This cross-sectional study was performed on individuals aged ≥18 years who were on HD at least 6 months before their enrollment in the study. A 4-day dietary recall was used for the evaluation of dietary intake. DAL was calculated using two methods including potential renal acid load (PRAL) and net endogenous acid production (NEAP). For assessing the malnutrition status, we used the subjective global assessment (SGA), dialysis malnutrition score (DMS), and malnutrition inflammation score (MIS). Fasting blood samples were collected from each participant to assess serum levels of high-sensitivity C-reactive protein (hs-CRP), soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular adhesion molecule-1 (sVCAM-1), sE-selectin, malondialdehyde (MDA), nitric oxide (NO), and endothelin-1.

Results

In total, 291 patients with a mean age of 57.73 ± 0.88 years and HD vintage of 4.27 ± 0.25 months were enrolled in the current study. Significant positive associations were observed between PRAL and hs-CRP (β = 1.77, 95% CI: 0.88, 2.65), sICAM-1 (β = 83.21, 95% CI: 10.39, 156.04), sVCAM-1 (β = 194.63, 95% CI: 74.68, 314.58), and sE-selectin (β = 6.66, 95% CI: 1.81, 11.50) among participants with the highest PRAL scores, compared to those with the lowest PRAL scores. NEAP was positively correlated with hs-CRP (β = 1.34, 95% CI: 0.46, 2.22), sICAM-1 (β = 88.83, 95% CI: 16.99, 160.67), and MDA (β = 0.35, 95% CI: 0.005, 0.71). Additionally, marginally significant higher odds of SGA (OR = 1.98, 95% CI: 0.95, 4.11) and DMS (OR = 1.94, 95% CI: 0.92, 4.05) were observed in individuals in the third tertile of PRAL vs. the first tertile of PRAL. NEAP had also a marginally significant positive correlation with DMS (OR = 2.01, 95% CI: 0.93, 4.31).

Conclusion

This study illustrates that higher consumption of acidic foods is correlated with markers of inflammation, oxidative stress, and malnutrition in HD patients.

The Role of Uremic Retention Solutes in the MIA Syndrome in Hemodialysis Subjects

INTRODUCTION

In chronic kidney disease (CKD), the high morbidity and mortality risk for cardiovascular disease (CVD) are not easily explained only on the basis of traditional factors. Among nontraditional ones involved in CKD, malnutrition, inflammation, and atherosclerosis/calcification have been described as the "MIA syndrome."

METHODS

In this pilot study, we evaluated the association between the variation in serum levels of 27 uremic retention solutes plus 6 indexes related to the MIA syndrome processes in a population of dialysis patients.

RESULTS

As expected, we found a direct correlation between serum albumin and both phosphate and total cholesterol (r = 0.54 and 0.37, respectively; p < 0.05). Moreover, total cholesterol and phosphate directly correlate (r = 0.40, p < 0.05). The relationship between malnutrition and inflammation is highlighted by the correlation of serum cholesterol levels with serum alpha-1 acid glycoprotein and IL-6 levels (r = -0.56, r = -0.39, respectively; p < 0.05). Moreover, the relation between inflammation and atherosclerosis/calcification is supported by the correlation of IL-6 with VEGF levels and vascular smooth muscle cell high-Pi in vitro calcification (r = 0.81, r = 0.66, respectively; p < 0.01).

CONCLUSION

We found significant correlations between several uremic retention solutes and malnutrition, inflammation, and atherosclerosis/calcification. Our findings support the hypothesis of a central role of the uremic milieu in the MIA syndrome and ultimately in the pathogenesis of CKD-specific CVD risk factors.

Non-Immunologic Causes of Late Death-Censored Kidney Graft Failure: A Personalized Approach

Despite continuous advances in surgical and immunosuppressive protocols, the long-term survival of transplanted kidneys is still far from being satisfactory. Antibody-mediated rejection, recurrent autoimmune diseases, and death with functioning graft are the most frequent causes of late-kidney allograft failure. However, in addition to these complications, a number of other non-immunologic events may impair the function of transplanted kidneys and directly or indirectly lead to their failure. In this narrative review, we will list and discuss the most important nonimmune causes of late death-censored kidney graft failure, including quality of the donated kidney, adherence to prescriptions, drug toxicities, arterial hypertension, dyslipidemia, new onset diabetes mellitus, hyperuricemia, and lifestyle of the renal transplant recipient. For each of these risk factors, we will report the etiopathogenesis and the potential consequences on graft function, keeping in mind that in many cases, two or more risk factors may negatively interact together.

Team Approach: Nutritional Assessment and Interventions in Elective Hip and Knee Arthroplasty

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Nutritional assessment is a critical element of routine preoperative assessment and should be approached by an interdisciplinary team that involves the primary care physician, dietitian, and orthopaedist.

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Patients should be stratified on the basis of their nutritional risk, which influences downstream optimization and deficiency reversal.

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The scientific literature indicates that nutritional supplementation affords protection against adverse outcomes and helps functional recovery, even among patients who are not at nutritional risk.

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Published investigations recommend a sufficient preoperative interval (at least 4 weeks) to ensure an adequate nutritional intervention in malnourished patients as opposed to regarding them as nonsurgical candidates.

Glasgow prognostic score can be a prognostic indicator after percutaneous coronary intervention: a two-center study in Japan

Glasgow prognostic score (GPS) has been used to evaluate inflammatory response and nutritional status. This study aimed to investigate the impact of nutritional status on cardiac prognosis by using GPS in patients after undergoing percutaneous coronary intervention (PCI). We included 862 patients who underwent PCI for stable angina pectoris between 2015 and 2018. We used the original cutoff values, which were an albumin (Alb) level of 3.5 g/dl and a C-reactive protein (CRP) level of 0.3 mg/dl. We categorized them into the three groups: originally defined GPS (od-GPS) 0 (high Alb and low CRP), 1 (low Alb or high CRP), and 2 (low Alb and high CRP). Major adverse clinical events (MACEs) included all-cause death, nonfatal myocardial infarction, revascularization, and hospitalization for heart failure. The median follow-up period was 398.5 days. During the follow-up, MACEs occurred in 136 patients. Od-GPS 2 had higher prevalence rates in terms of chronic kidney disease (CKD; 31.7% [229/722] vs. 44.9% [53/118] vs. 63.6% [14/22], p < 0.001), hemodialysis (6.4% [46/722] vs. 14.4% [17/118] vs. 31.8% [7/22], p < 0.001), and heart failure cases (HF; 9.1% [66/722] vs. 14.4% [17/118] vs. 27.3% [6/22], p = 0.007), with higher creatinine (1.17 ± 1.37 mg/dl vs. 1.89 ± 2.60 mg/dl vs. 3.49 ± 4.01 mg/dl, p < 0.001) and brain natriuretic peptide levels (104.1 ± 304.6 pg/ml vs. 242.4 ± 565.9 pg/ml vs. 668.1 ± 872.2 pg/ml, p < 0.001) and lower low-density lipoprotein cholesterol (101.5 ± 32.9 mg/dl vs. 98.2 ± 28.8 mg/dl vs. 77.1 ± 24.3 mg/dl, p = 0.002) than od-GPS 0 and 1.Od-GPS 2 (HR 2.42; 95% CI 1.16-5.02; p = 0.018), od-GPS 1 (HR 2.09; 95% CI 1.40-3.13; p < 0.001), diabetes (HR 1.41; 95% CI 1.00-1.99; p = 0.048), CKD (HR 2.10; 95% CI 1.49-2.96; p < 0.001), and HF (HR 1.64; 95% CI 1.05-2.56; p = 0.029) were independent predictors of MACEs. A scoring system using CRP and Alb levels with a milder definition than GPS suitably predicted the risk of MACEs in the patients who underwent PCI.

The inflammatory state is a risk factor for cardiovascular disease and graft fibrosis in kidney transplantation

Several factors, such as donor brain death, ischemia-reperfusion injury, rejection, infection, and chronic allograft dysfunction, may induce an inflammatory state in kidney transplantation. Furthermore, inflammatory cells, cytokines, growth factors, complement and coagulation cascade create an unbalanced interaction with innate and adaptive immunity, which are both heavily involved in atherogenesis. The crosstalk between inflammation and thrombosis may lead to a prothrombotic state and impaired fibrinolysis in kidney transplant recipients increasing the risk of cardiovascular disease. Inflammation is also associated with elevated levels of fibroblast growth factor 23 and low levels of Klotho, which contribute to major adverse cardiovascular events. Hyperuricemia, glucose intolerance, arterial hypertension, dyslipidemia, and physical inactivity may create a condition called metaflammation that concurs in atherogenesis. Another major consequence of the inflammatory state is the development of chronic hypoxia that through the mediation of interleukins 1 and 6, angiotensin II, and transforming growth factor beta can result in excessive accumulation of extracellular matrix, which can disrupt and replace functional parenchyma, leading to interstitial fibrosis and chronic allograft dysfunction. Lifestyle and regular physical activity may reduce inflammation. Several drugs have been proposed to control the graft inflammatory state, including low-dose aspirin, statins, renin-angiotensin inhibitors, xanthine-oxidase inhibitors, vitamin D supplements, and interleukin-6 blockade. However, no prospective controlled trial with these measures has been conducted in kidney transplantation.

Peridialytic serum cytokine levels and their relationship with postdialysis fatigue and recovery in patients on chronic haemodialysis - A preliminary study

BACKGROUND

The aetiology of postdialysis fatigue (PDF), an intermittent but debilitating fatigue occurring after haemodialysis (HD) treatment, is still unclear. In other inflammatory diseases, increasing evidence points toward the involvement of the immune system in the onset of fatigue symptoms. Altered serum levels of inflammatory cytokines have also been shown in HD patients. Therefore, we investigated whether pre- and postdialysis serum levels of pro- and anti-inflammatory cytokines (i.e. IL-1β, IL-6, TNF-α and IL-10) or their intradialytic changes (if any) were related to PDF or the time HD patients reported needing to recover from HD treatment (TIRD).

METHODS

Serum levels of IL-1β, IL-6, TNF-α and IL-10 were measured immediately before and after HD in 45 patients using commercially available kits on an ELLA™ automated immunoassay system. The presence and severity of PDF as well as TIRD duration were assessed by self-report measures.

KEY RESULTS

Seventy-four percent of patients reported PDF, with a median PDF severity index of 3.30 [IQR: 3.00-4.30] on a scale from 1 to 5. Median TIRD was 120 min [IQR: 60-480]. PDF severity correlated strongly with TIRD, r_s = 0.85, p < 0.001. Only predialysis levels of IL-10 significantly and positively correlated with PDF severity (r_s = 0.43, p = 0.003).

CONCLUSION

Findings of the present study do not support the involvement of the immune system in the onset of PDF or the time patients needed to recover from HD treatment. A positive, but counterintuitive relationship was found between predialysis levels of anti-inflammatory IL-10 and PDF severity, which warrants further research.

Intradialytic Nutrition and Hemodialysis Prescriptions: A Personalized Stepwise Approach

Dialysis and nutrition are two sides of the same coin—dialysis depurates metabolic waste that is typically produced by food intake. Hence, dietetic restrictions are commonly imposed in order to limit potassium and phosphate and avoid fluid overload. Conversely, malnutrition is a major challenge and, albeit to differing degrees, all nutritional markers are associated with survival. Dialysis-related malnutrition has a multifactorial origin related to uremic syndrome and comorbidities but also to dialysis treatment. Both an insufficient dialysis dose and excessive removal are contributing factors. It is thus not surprising that dialysis alone, without proper nutritional management, often fails to be effective in combatting malnutrition. While composite indexes can be used to identify patients with poor prognosis, none is fully satisfactory, and the definitions of malnutrition and protein energy wasting are still controversial. Furthermore, most nutritional markers and interventions were assessed in hemodialysis patients, while hemodiafiltration and peritoneal dialysis have been less extensively studied. The significant loss of albumin in these two dialysis modalities makes it extremely difficult to interpret common markers and scores. Despite these problems, hemodialysis sessions represent a valuable opportunity to monitor nutritional status and prescribe nutritional interventions, and several approaches have been tried. In this concept paper, we review the current evidence on intradialytic nutrition and propose an algorithm for adapting nutritional interventions to individual patients.

Impact of Periodontal Inflammation on Nutrition and Inflammation Markers in Hemodialysis Patients

Background: Malnutrition-inflammation complex syndrome (MICS) is a common and usually concurrent condition occurring in patients undergoing hemodialysis (HD), with a pathogenesis linked to biological and in situ environmental traditional risk factors. Periodontitis, one of the major types of infection-driven inflammation, often co-occurs in the in the hemodialysis population and correlates with markers of malnutrition and inflammation, such as albumin, creatinine, and C-reactive protein. Aim: The present study aimed to determine whether the periodontal inflammatory status parameters correlate with the albumin, creatinine, and C-reactive protein serum concentrations in HD patients, and investigate whether periodontal treatment improves these markers of nutritional and systemic inflammation. Materials and Methods: The serum creatinine, albumin, and C-reactive Protein (CRP) levels were measured at baseline and after non-surgical periodontal treatment, at 3 months and 6 months. Results: At 3 months, a significant correlation between plaque index and C-reactive protein (p = 0.012), bleeding on probing and C-reactive protein (p < 0.0019), and clinical attachment level and C-reactive protein (p = 0.022) was found. No significant correlation was found between clinical periodontal parameters and nutrition markers at each time. Conclusions: Our results confirmed the association between C-reactive protein serum concentration and periodontal inflammatory status, but further research is necessary to identify the contributing role of periodontitis on the onset and progression of MICS.

Interleukin-1β Gene (IL1B) Polymorphism and Risk of Developing Diabetic Nephropathy

Objective: Cytokines play an important role in the pathogenesis of type 2 diabetes (T2DM) and its complications. The aim of the study was to evaluate an association of the -511 (C/T) polymorphism in the IL1B gene with diabetic nephropathy (DN). Methods: The study population included 860 patients with T2DM (506 with diabetic nephropathy and 354 without nephropathy) as well as 505 healthy individuals. Genomic DNA was genotyped for the IL1B -511 (C/T) polymorphism using PCR-RFLP technique. Results: The IL1B -511 C/T polymorphism was genotyped in 860 T2DM patients with or without DN and 505 healthy individuals. The average age of patients was 65.3 years in DN+ and 62.2 years in DN- subgroups. The genotype distribution did not differ significantly between patients and controls. Only a tendency to a slight increase of T allele frequency was observed in patient group. Genotype and allele frequencies of -511 C/T polymorphism were compared in patients with DN and those without it. The minor allele (T) and homozygote TT frequencies were significantly different between subgroups. The T allele was more frequent in DN+ patients, with odds ratio 1.45 (95% CI 1.2-1.8), p = 0.0003. The TT genotype frequency was also higher in DN+, with OR 1.76 (96% CI 1.1-2.7), p = 0.01. Conclusion: In a studied population the -511 C/T polymorphism in the IL1B gene is associated with diabetic nephropathy in dialyzed T2DM patients. Further studies are required to confirm the clinical significance of this finding.

Selected Phytoestrogens Distinguish Roles of ERα Transactivation and Ligand Binding for Anti-Inflammatory Activity

Estrogen receptor α (ERα) is a ligand-activated transcriptional activator that is also involved vascular inflammation and atherosclerosis. Whether different ligands may affect this activity has not been explored. We screened a panel of phytoestrogens for their role in ERα binding and transcriptional transcription, and correlated the findings to anti-inflammatory activities in vascular endothelial cells stably expressing either a wild-type or mutant form of ERα deficient in its membrane association. Taxifolin and silymarin were "high binders" for ERα ligand binding; quercetin and curcumin were "high activators" for ERα transactivation. Using these phytoestrogens as functional probes, we found, in endothelial cells expressing wild-type ERα, the ERα high activator, but not the ERα high binder, promoted ERα nuclear translocation, estrogen response element (ERE) reporter activity, and the downstream gene expression. In endothelial cells expressing membrane association-deficient mutant ERα, the ERα nuclear translocation was significantly enhanced by taxifolin and silymarin, which still failed to activate ERα. Inflammation response was examined using the systemic or vascular inflammation inducers lipopolysaccharide or oxidized low-density lipoprotein. In both cases, only the ERα high activator inhibited nuclear translocation of nuclear factor κB, JNK, and p38, and the production of inflammatory cytokines IL-1β and TNFα. We confirm a threshold nuclear accumulation of ERα is necessary for its transactivation. The anti-inflammatory activity of phytoestrogens is highly dependent on ERα transactivation, less so on the ligand binding, and independent of its membrane association. A pre-examination of phytoestrogens for their mode of ERα interaction could facilitate their development as better targeted receptor modifiers.

The Obesity Paradox in Kidney Disease: How to Reconcile it with Obesity Management

Obesity, a risk factor for de novo chronic kidney disease (CKD), confers survival advantages in advanced CKD. This so-called obesity paradox is the archetype of the reverse epidemiology of cardiovascular risks, in addition to the lipid, blood pressure, adiponectin, homocysteine, and uric acid paradoxes. These paradoxical phenomena are in sharp contradistinction to the known epidemiology of cardiovascular risks in the general population. In addition to advanced CKD, the obesity paradox has also been observed in heart failure, chronic obstructive lung disease, liver cirrhosis, and metastatic cancer, as well as in the elderly. These are populations in whom protein-energy wasting and inflammation are strong predictors of early death. Both larger muscle mass and higher body fat provide longevity in these patients, whereas thinner body habitus and weight loss are associated with higher mortality. Muscle mass appears to be superior to body fat in conferring an even greater survival. The obesity paradox may be the result of a time discrepancy between competing risk factors, i.e., overnutrition as the long-term killer versus undernutrition as the short-term killer. Hemodynamic stability of obesity, lipoprotein defense against circulating endotoxins, protective cytokine profiles, toxin sequestration of fat mass, and antioxidation of muscle may play important roles. Despite claims that obesity paradox is a statistical fallacy and a result of residual confounding, the consistency of data and other causality clues suggest a high biologic plausibility. Examining the causes and consequences of the obesity paradox may help discover important pathophysiologic mechanisms leading to improved outcomes in patients with CKD.

New Insight into Atherosclerosis in Hemodialysis Patients: Overexpression of Scavenger Receptor and Macrophage Colony-Stimulating Factor Genes

BACKGROUND

Scavenger receptors (SRs) play a pivotal role in atherogenesis. The mechanism of atherosclerosis, which is specific to hemodialysis (HD) patients, was studied on the basis of SR gene expressions.

METHODS

The gene expressions of SR type A (SR-A) and CD36 were studied in peripheral monocytes by real-time reverse transcription polymerase chain reaction. Data were compared between HD (n = 30) and age-matched control subjects (n = 10). Serum levels of macrophage colony-stimulating factor (M-CSF) were measured with enzyme-linked immunosorbent assay to test its role in SR expression. The statistical differences and associations between two continuous variables were assessed using the Mann-Whitney U test and Pearson's correlation coefficient, respectively.

RESULTS

The relative quantities of SR mRNAs were significantly greater in HD patients than in controls [median (interquartile range): SR-A, 1.67 (0.96-2.76) vs. 0.90 (0.60-1.04), p = 0.0060; CD36, 1.09 (0.88-1.74) vs. 0.74 (0.64-0.99), p = 0.0255]. The serum concentration of M-CSF was significantly higher in HD patients than in controls [1, 121 (999-1,342) vs. 176 (155-202) pg/ml, p < 0.0001]. In addition, the relative quantity of M-CSF mRNA was significantly greater in HD patients than in controls [0.79 (0.42-1.53) vs. 0.42 (0.28-0.66), p = 0.0392]. The serum M-CSF levels were positively correlated with both the relative quantity of SR-A mRNA (r² = 0.1681, p = 0.0086) and that of CD36 mRNA (r² = 0.1202, p = 0.0284) in all subjects (n = 40).

CONCLUSION

HD patients are predisposed to atherosclerosis as a consequence of their enhanced monocyte SR expressions. SRs and M-CSF are potential therapeutic targets for atherosclerosis in this high-risk population.

Unexpected Normal Colloid Osmotic Pressure in Clinical States with Low Serum Albumin

BACKGROUND

In clinical states associated with systemic oxidative stress (OS) and inflammation such as chronic kidney disease (CKD), oxidative modifications of serum albumin impair its quantification, resulting in apparent hypoalbuminemia. As the maintenance of oncotic pressure/colloid osmotic pressure (COP) is a major function of albumin, this study examined the impact of albumin oxidation on COP, both in-vivo and in-vitro.

METHODS

Patients with proteinuria and patients on chronic hemodialysis (HD) with systemic inflammation and OS were enrolled. Blood samples were collected from 134 subjects: 32 healthy controls (HC), proteinuric patients with high (n = 17) and low (n = 31) systemic inflammation and from 54 patients on chronic hemodialysis (HD) with the highest levels of OS and inflammation.

RESULTS

In-vitro oxidized albumin showed significantly higher COP values than non-oxidized albumin at identical albumin levels. In vivo, in hypoalbuminemic HD patients with the highest OS and inflammation, COP values were also higher than expected for the low albumin levels. The contribution to COP by other prevalent plasma proteins, such as fibrinogen and immunoglobulins was negligible. We imply that the calculation of COP based on albumin levels should be revisited in face of OS and inflammation. Hence, in hypoalbuminemic proteinuric patients with systemic OS and inflammation the assumption of low COP should be verified by its measurements.

Role of cytokine gene polymorphisms in acute and chronic kidney disease following liver transplantation

PURPOSE

Development of renal dysfunction, including acute kidney injury (AKI) and chronic kidney disease (CKD), after liver transplantation (LT) remains a critical issue adversely affecting patient survival in both the short and long term. Previous reports have suggested that inflammatory and antiinflammatory cytokines and their functionally relevant gene polymorphisms may play critical roles in the development of AKI and CKD. However, the involvement of these cytokines and their gene polymorphisms in renal deterioration following LT remains unclear.

METHODS

We examined 62 recipients who underwent LT at Nagoya University between 2004 and 2009 and who had survived for at least 1 year. The following gene polymorphisms in recipients were analyzed: tumor necrosis factor-A (TNFA) T-1031C, interleukin-2 (IL2) T-330G, IL10 C-819T, IL13 C-1111T, transforming growth factor-B (TGFB) T29C, and IL4 T-33C.

RESULTS

Thirteen patients (21 %) developed AKI within 4 weeks after LT. Of the investigated gene polymorphisms, the IL4 -33 T/T genotype was significantly associated with higher incidence of AKI compared with the other two genotypes [hazard ratio (HR) = 5.48, 95 % confidence interval (CI) 1.18-25.52, p = 0.03]. On the other hand, 16 patients (26 %) had developed CKD at median follow-up of 9.2 years after LT. We showed the lack of association between investigated gene polymorphisms in recipients and CKD development.

CONCLUSIONS

The IL4 -33 T/T genotype might be a risk factor for AKI in LT, and this might contribute to earlier withdrawal of immunosuppressive agents to minimize renal toxicity. In contrast, none of the investigated cytokine gene polymorphisms were associated with CKD.

Predictive value of echocardiography and its relation to Kt/V and anthropometric parameters in hemodialysis patients

BACKGROUND

In order to evaluate the predictive value of echocardiograph parameters for mortality of hemodialysis patients and their relation to Kt/V and anthropometry, a prospective, single center study was analyzed post-hoc.

METHODS

This analysis encompassed 106 patients on maintenance hemodialysis monitored for 108 months from 1996 to 2004. spKt/V was calculated using the Daugirdas formula. Anthropometric measurements included mid-arm muscle measurements (MAMC) and percentage of body fat (%fat). Echocardiography included the estimations of left ventricular wall thickness, dimensions and volumes (EDV, ESV), systolic LV function (ejection fraction - EFLV, fractional shortening - VCF, stroke volume - SV) and diastolic LV function (E/A, VTI-A wave of transmitral flow velocity), left atrial diameter, as well as assessment of clinical and biochemical parameters. The Cox proportional hazard model was used to estimate predictive values of echocardiograph parameters.

RESULTS

Kt/V correlated significantly with left ventricular systolic and diastolic volumes and function, septal and posterior wall thickness and left atrium dimension. MAMC and %fat also correlated with many echocardiograph parameters. Multivariate Cox regression selected age [HR 1.07; CI (1.03-1.12); p < 0.01], albumin [HR 0.88; CI (0.79-0.97); p < 0.05] and left atrium dimension - binary [values > 4 cm were marked as "1" and others "0" - HR 3.76; CI (1.56-9.03); p < 0.01] as independent predictors of death.

CONCLUSION

Left atrium dimension was the most important predictor of mortality among the echocardiograph parameters. Many of these parameters were related to Kt/V and anthropometric measurements and could be the combined consequence of hypervolemia and hypertension.

Obesity, metabolic health, and the risk of end-stage renal disease

Obesity is associated with chronic kidney disease progression. Whether metabolic risk factors modify this association is unclear. Here we examined associations of body mass index (BMI) and metabolic health with risk of end-stage renal disease (ESRD) in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study. Among 21,840 participants eligible for analysis, 247 developed ESRD (mean follow-up of 6.3 years). Metabolic health significantly modified the association of BMI with ESRD. In models stratified by the presence or absence of the metabolic syndrome and adjusted for demographic, lifestyle, and clinical factors, higher BMI was associated with lower risk of ESRD in those without (hazard ratio per 5 kg/m2 increase in BMI 0.70, 95% CI 0.52, 0.95) but not those with (hazard ratio, 1.06) the metabolic syndrome. In models stratified by weight and metabolic health, compared with normal weight (BMI 18.5-24.9 kg/m2) participants without the metabolic syndrome the overweight individuals (BMI 25-29.9) and obese individuals (BMI of 30 or more) with the metabolic syndrome had greater risk of ESRD (hazard ratios of 2.03 and 2.29, respectively), whereas obesity without the metabolic syndrome was associated with lower risk of ESRD (hazard ratio 0.47). Thus, higher BMI is associated with lower ESRD risk in those without but not those with the metabolic syndrome.

Insulin resistance and left ventricular mass in non-diabetic hemodialysis patients

BACKGROUND

Insulin resistance (IR) is frequently recognized in patients with uremia, and it is thought that IR has a basic role in the pathogenesis of cardiovascular disease.

OBJECTIVE

To evaluate the effect of IR on cardiovascular risk in non-diabetic patients receiving hemodialysis (HD).

METHODS

We performed a cross-sectional observational study that comprised 186 non-diabetic patients receiving HD (95 men; mean [SD] age, 46.4 [10.8] years; age range, 35-60 years) who had been receiving HD for 7.3 (3.5) years. Demographic variables and laboratory values were recorded. Insulin resistance was determined using the Homeostatic Model Assessment (HOMA), and the left ventricular mass index (LVMI) was calculated via echocardiography.

RESULTS

According to HOMA-IR levels, patients were categorized as having IR (HOMA-IR score ≥2.5; n = 53) or not having IR (HOMA-IR score <2.5; n = 133). Insulin resistance was determined in 28.4% of study patients. Compared with the non-IR group, the IR group had been receiving HD longer; had greater body mass index; and had higher serum creatinine, uric acid, triglyceride, insulin, and C-reactive protein concentrations, leukocyte count, and LVMI (P < 0.05). Patients with increased LVMI had significantly higher body mass index, systolic blood pressure, serum cholesterol and C-reactive protein concentrations, and HOMA score. At multivariate analysis, systolic blood pressure (β = 0.22; P = 0.03) and HOMA score (β = 0.26; P = 0.01) affected LVMI.

CONCLUSIONS

Insulin resistance and hypertension are independent risk factors for left ventricular hypertrophy in non-diabetic patients with uremia who are receiving HD. Further studies are needed to indicate the benefits of improving IR for cardiovascular mortality in this subgroup of patients with uremia.

Transcription factor 7-like 2 (TCF7L2) gene polymorphism and clinical phenotype in end-stage renal disease patients

Variants of the transcription factor 7-like 2 gene (TCF7L2) have been associated with type 2 diabetes and cardiovascular disease in different populations. Here we investigated the potential association of the rs7903146 polymorphism in the TCF7L2 gene with clinical profile of end-stage renal disease (ESRD) patients. We examined a cohort of 1065 ESRD patients with diabetic and non-diabetic renal disease. The control group consisted of 924 healthy individuals. All subjects were genotyped for the rs7903146 single nucleotide polymorphism by polymerase chain reaction. The genotype distribution and allele frequencies were significantly different between ESRD patients and controls (p < 0.01). The OR for the TT genotype was 2.81 (95 % CI 2.08–3.79). Genotype and allele frequencies were compared between subgroups of patients with different clinical phenotypes. The frequency of the T allele was significantly higher in patients with diabetic nephropathy versus non-diabetic renal disease (p = 0.007, OR 1.70, 95 % CI 1.36–2.11). The statistically significant differences were demonstrated between patients with and without cardiovascular disease, with the OR for T allele 1.57 (95 % CI 1.31–1.90). The odds ratio for TT genotype was 2.38 (95 % CI 1.62–3.51). In our study the T allele of the rs7903146 SNP in the TCF7L2 gene confers the risk of developing diabetic nephropathy. We described for the first time a strong relationship between the TCF7L2 gene variant rs7903146 and cardiovascular disease in end-stage renal disease patients.

Effect of different hemodialyzers on serum levels of interleukin-6, interleukin-10 and interleukin-18

BACKGROUND

The blood and membrane contact during dialysis may elicit an immune reaction. The current study looked at the impact of different dialyzers on blood levels of cytokines.

METHODS

During the first month, randomly selected patients were treated with one dialyzer (PF-170H) and then crossed over to another dialyzer (FLX-18GW) during the next month. Pre- and postdialysis blood samples were assayed for interleukin (IL)-6, IL-10 and IL-18.

RESULTS

A significant drop of postdialysis systolic blood pressure (pre vs. post 156.4 ± 31.8 vs. 143.1 ± 24.8 mm Hg, p = 0.014) and diastolic pressure (80.7 ± 12.7 vs. 73.4 ± 10.9 mm Hg, p = 0.002) were found when patients were dialyzed with PF-170H. A significant increase of postdialysis IL-18 levels was found in both groups (pre vs. post 605.5 ± 278.6 vs. 690.6 ± 315.3 pg/ml, p = 0.016, for PF-170H and 556.4 ± 231.0 vs. 647.3 ± 282.6 pg/ml, p = 0.067, for FLX-18GW). There was a positive correlation between IL-6 and IL-10 levels (p < 0.0001).

CONCLUSION

We demonstrated a significant increase of postdialysis serum IL-18 level when either dialyzer was used. There is a strong correlation between serum levels of IL-6 and IL-10.

Blood monocyte count may be a predictor of vascular access failure in hemodialysis patients

It has been reported that an increase in the counts of white blood cells (WBC) and their subpopulations is an independent predictor of atherosclerotic events and mortality. On the other hand, vascular access (VA) stenosis is caused by a progressive development of neointimal hyperplasia. We examined the relationship between VA failure and counts of peripheral WBC and their subpopulations in hemodialysis (HD) patients. The study population consisted of 82 patients undergoing regular HD. Twenty-two patients, who were unstable, were excluded from the study. After one year, we examined the relationship between VA failure and the counts of peripheral WBC and their subpopulations. In the follow-up period, 21 patients had complicated VA failure. The counts of WBC, neutrophils, lymphocytes, eosinophils, and basophils did not show a significant difference, but a monocyte count of ≥ 400/μL was shown to indicate a high probability of VA failure. Logistic regression analysis revealed that monocyte count was an independent risk factor of VA failure. The peripheral blood monocyte count may be a predictor of VA failure in HD patients.

Obesity paradox in end-stage kidney disease patients

In the general population, obesity is associated with increased cardiovascular risk and decreased survival. In patients with end-stage renal disease (ESRD), however, an "obesity paradox" or "reverse epidemiology" (to include lipid and hypertension paradoxes) has been consistently reported, i.e. a higher body mass index (BMI) is paradoxically associated with better survival. This survival advantage of large body size is relatively consistent for hemodialysis patients across racial and regional differences, although published results are mixed for peritoneal dialysis patients. Recent data indicate that both higher skeletal muscle mass and increased total body fat are protective, although there are mixed data on visceral (intra-abdominal) fat. The obesity paradox in ESRD is unlikely to be due to residual confounding alone and has biologic plausibility. Possible causes of the obesity paradox include protein-energy wasting and inflammation, time discrepancy among competitive risk factors (undernutrition versus overnutrition), hemodynamic stability, alteration of circulatory cytokines, sequestration of uremic toxin in adipose tissue, and endotoxin-lipoprotein interaction. The obesity paradox may have significant clinical implications in the management of ESRD patients especially if obese dialysis patients are forced to lose weight upon transplant wait-listing. Well-designed studies exploring the causes and consequences of the reverse epidemiology of cardiovascular risk factors, including the obesity paradox, among ESRD patients could provide more information on mechanisms. These could include controlled trials of nutritional and pharmacologic interventions to examine whether gain in lean body mass or even body fat can improve survival and quality of life in these patients.

Correlation of hemochromatosis gene mutations and cardiovascular disease in hemodialysis patients

BACKGROUND AND OBJECTIVES

Cardiovascular disease (CVD) is a major cause of death in hemodialysis (HD) patients. Hemochromatosis (HFE) gene mutations are reported to be associated with CVD. The present study aims to investigate the association of HFE gene polymorphism with CVD in HD patients.

DESIGN AND SETTINGS

Cross-sectional case-control.

METHODS

C282Y/H63D mutations of HFE gene were evaluated in 560 HD patients and 480 healthy controls from 4 HD centers in North China. The results obtained from this evaluation process were correlated with biochemical parameters including iron status (serum iron, ferritin, and transferrin concentration), cardiovascular disease, and inflammation marker CRP, IL-6, TNF-a.

RESULTS

No C282Y mutations were detected in HD patients or healthy controls in this study. The genotype of H63D heterozygous mutation was similar in HD patients with CVD, HD patients without CVD, and controls. H63D homozygous mutation was 7.4% (19/257), 3.1% (9/303), and 1.0% (5/480) for the 3 groups, respectively. Compound heterozygosity was not found in this study. The relative risk for CVD in HD patients with H63D homozygous mutation was 2.59 (95% CI: 1.15-5.84). H63D homozygous mutation had significantly higher serum ferritin concentrations compared with wild-type individuals. Moreover, HD patients had significantly higher levels of inflammatory biomarkers such as CRP, IL-6, and TNF-a. The multivariate logistic regression analysis revealed that H63D mutation instead of ferritin level was an independent risk factor of CVD for HD patients.

CONCLUSIONS

Our study demonstrates for the first time that there was an association between H63D homozygous mutations and CVD in HD patients. Elevated serum CRP, IL-6, and TNF-a levels were also related to CVD in HD patients.

Circulating levels of inflammation-associated miR-155 and endothelial-enriched miR-126 in patients with end-stage renal disease

Circulating microRNAs (miRNAs) may represent a potential noninvasive molecular biomarker for various pathological conditions. Moreover, the detection of circulating miRNAs can provide important novel disease-related information. In particular, inflammation-associated miR-155 and endothelial-enriched miR-126 are reported to be associated with vascular homeostasis. Vascular damage is a common event described in end-stage renal disease (ESRD). We hypothesized that miR-155 and miR-126 may be detectable in the circulation and serve as potential biomarkers for risk stratification. In this study, we assessed miR-155 and miR-126 in the plasma of 30 ESRD patients and 20 healthy controls using real-time quantification RT-PCR. The circulating levels of miR-155 and miR-126 were significantly reduced in patients with ESRD compared to healthy controls. However, there was no significant difference of circulating miR-155 and miR-126 levels between prehemodialysis and posthemodialysis patients. Furthermore, both circulating miR-126 and miR-155 correlated positively with estimated glomerular filtration rate (miR-126: r = 0.383, P = 0.037; miR-155: r = 0.494, P = 0.006) and hemoglobin (miR-126: r = 0.515, P = 0.004; miR-155: r = 0.598, P < 0.001) and correlated inversely with phosphate level (miR-126: r = -0.675, P < 0.001; miR-155: r = -0.399, P = 0.029). Pearson's correlation was used to compare circulating levels of miRNAs with clinical parameters. These results suggested that circulating miR-155 and miR-126 might be involved in the development of ESRD. Further studies are needed to demonstrate the role of circulating miR-155 and miR-126 as candidate biomarkers for risk estimation.

Interleukin-6 -634 C/G and -174 G/C polymorphisms in Korean patients undergoing hemodialysis

BACKGROUND/AIMS

Chronic inflammatory status is a possible risk factor for vascular access dysfunction in hemodialysis (HD) patients, but susceptibility differences appear among individuals. Interleukin (IL)-6 is a well-known inflammatory cytokine with various polymorphisms. We examined whether IL-6 polymorphisms are associated with vascular access dysfunction in HD patients.

METHODS

A total of 80 HD patients (including 42 diabetic patients) were enrolled. Polymorphisms in the IL-6 gene promoter (-634 C/G and -174 G/C) were studied using restriction length polymorphism polymerase chain reaction analysis. Vascular access patency was compared between the patient groups with respect to IL-6 polymorphisms. An additional 89 healthy individuals were enrolled in the control group. Plasma IL-6 levels were determined by enzyme-linked immunosorbent assay.

RESULTS

The GG genotype and G allele at position -634 in the IL-6 promoter were more frequently observed in HD patients than in controls. Furthermore, the distribution of the -634 polymorphism differed according to vascular access patency in non-diabetic HD patients. However, the G allele was not a significant risk factor for early access failure. No significant association appeared between the IL-6 -634 C/G polymorphism and plasma IL-6 levels. The C allele of the IL-6 -174 G/C polymorphism was not detected in our study population.

CONCLUSIONS

The IL-6 -634 G allele appears with greater frequently in patients with end-stage renal disease and may be associated with vascular access dysfunction in non-diabetic HD patients.

Tumor Necrosis Factor-α Gene Polymorphism Correlates with Cardiovascular Disease in Patients with End-Stage Renal Disease

BACKGROUND AND OBJECTIVE

Tumor necrosis factor-alpha (TNFalpha) is a potent proinflammatory cytokine. Through its effects on lipid metabolism and endothelial function, TNFalpha is involved in cardiovascular disease (CVD). We have studied two polymorphisms in the promoter region of the TNFalpha gene (TNF -308G/A and TNF -238G/A) in end-stage renal disease (ESRD) patients with and without CVD. The aim was to assess the association of these polymorphisms with ESRD and cardiovascular comorbidity in hemodialyzed patients.

METHODS

A total of 603 patients with ESRD treated with hemodialysis (382 patients with CVD) and 325 healthy control subjects were genotyped for the TNF -308G/A and TNF -238G/A ploymorphisms by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) procedure.

RESULTS

The A allele of the TNF -308 polymorphism was more frequent in the ESRD group than in control individuals. The odds ratio (OR) for the risk allele was 2.05 (95% CI 1.48, 2.84). In the subgroup of ESRD patients with CVD, the OR was 5.76 (95% CI 3.67, 9.03) relative to ESRD patients without CVD. There was no association observed between the TNF -238 polymorphism and renal failure or CVD in ESRD patients.

CONCLUSION

Our results demonstrate for the first time that the A allele of the TNF -308 polymorphism is associated with CVD in hemodialyzed ESRD patients. If confirmed in prospective studies, it may be a predictor of increased susceptibility to CVD in these patients.

The intercellular adhesion molecule-1 (ICAM-1) gene polymorphism K469E in end-stage renal disease patients with cardiovascular disease

The intercellular adhesion molecule-1 (ICAM-1) mediates interaction of activated endothelial cells with leukocytes. It plays an important role in the pathogenesis of atherosclerosis. A functionally important polymorphism of the ICAM-1 gene, K469E, has been described. We investigated whether this polymorphism influences the risk of CVD in end-stage renal disease (ESRD) patients. The groups of 1016 ESRD patients and 824 healthy individuals were genotyped by PCR and allele specific oligonucleotide technique. The T allele of the K469E polymorphism was significantly more frequent in ESRD CVD+ patients than CVD- and controls (OR 2.26, 95% CI 1.87-2.72 and 1.82, 95% CI 1.55-2.11, respectively). The TT genotype was also more frequent in CVD+ patients (OR 9.90, 95% CI 6.17-15.88 vs. CVD- subgroup). When patients were stratified according to clinical outcome of CVD, there was a tendency towards higher frequencies of the T allele and TT genotype in patients with myocardial infarction (OR for T allele 1, 57, 95% CI 1.12-2.18 vs. patients without MI). In the multivariate regression analysis the carrier status of T allele of K469E was an independent risk factor of susceptibility to CVD. Our data suggest that the ICAM-1 K469E polymorphism is associated with CVD in ESRD patients.

Impact of cytokine genotype on cardiovascular surrogate markers in hemodialysis patients

BACKGROUND/AIMS

Cytokine gene polymorphisms have been implicated as potential genetic risk factors for cardiovascular diseases (CVDs). Atherosclerosis and left ventricular hypertrophy (LVH) are surrogate markers for CVDs in uremic patients. The aim of this study was to assess the role of cytokine gene polymorphisms in carotid intima-media thickness (CIMT) and left ventricular mass index (LVMI) progression in nondiabetic hemodialysis (HD) patients.

METHODS

About 102 nondiabetic patients on maintenance HD were included in this study. Patients were followed up for 2 years. Genetic polymorphisms of TNF-alpha (-308 G/A, -238A/G) and IL-10 (-1082 A/G, -819 C/T, -592 A/C) were determined by polymerase chain reaction. Biochemical parameters and inflammatory markers and ambulatory blood pressure (BP) measurements were determined during the study period. CIMT and LVMI were also determined at baseline and after the first and second year.

RESULTS

Cardiovascular risk factors did not differ between TNF-alpha -308 high-/low-producer genotype groups. However, CIMT and LVMI progression were detected at higher levels in patients with high-producer genotypes (AA+AG) than in patients with the low-producer genotype (GG) during the study period. The TNF-alpha -308 G/A polymorphism was closely associated with C-reactive protein (CRP), a marker of systemic inflammation in the study population. Analysis also showed that the combination of high production of TNF-alpha and low production of IL-10 was associated with higher average IMT and LVMI progression and elevated average CRP levels compared with a combination of low production of TNF-alpha and high production of IL-10.

CONCLUSION

Polymorphisms in inflammatory genes may represent an additional factor affecting inflammation and CVD progression in nondiabetic HD patients.

Conventional, but not high-purity, dialysate-induced monocyte apoptosis is mediated by activation of PKC-delta and inflammatory factors release

BACKGROUND

Use of conventional dialysate (CD) (powdered sodium bicarbonate dissolved manually with reverse osmosis water before dialysis) is common in Chinese haemodialysis (HD) centres. However, this preparation carries the risk of degradation and contamination, potentially negatively impacting host defense. Commercially available high-purity dialysate (HPD) may decrease inflammation and improve nutritional status in HD patients. However, whether HPD affects immune cells is unclear. The purpose of this study was to investigate the in vitro effect of these dialysates on apoptosis in U937 monocytes and its possible mechanism.

METHODS

Following incubation with two different types of dialysate, U937 cell apoptosis was measured by flow cytometry. Cell morphological changes were observed by Hoechst 33258 fluorescence staining. The expression of protein kinase C-δ (PKC-δ) was assayed by RT-polymerase chain reaction and western blot. Cytokine levels in U937 cells after exposure to CD or HPD for an indicated time were assayed by commercial enzyme-linked immunosorbent assay.

RESULTS

CD contained more bacteria (66 ± 6 CFU/mL) than HPD (7 ± 3 CFU/mL) while there was no difference in endotoxin levels. Compared with cells exposed to HPD and phosphate-buffered saline (PBS), U937 monocytes experienced more apoptosis when exposed to CD for 24 and 48 h, while there was no significant difference between HPD and PBS. Expressions of PKC-δ mRNA and protein in U937 cells were enhanced following exposure to CD for 24 and 48 h, with increased proteolytic cleavage of PKC-δ which could be inhibited by rottlerin, a specific inhibitor of PKC-δ. Moreover, the cultured supernatant in CD-exposed cells contained significantly higher levels of interleukin-6 (4.09 ± 0.36 vs 2.73 ± 0.38 pg/mL, P < 0.01, 24 h; 4.28 ± 0.32 vs 2.83 ± 0.32 pg/mL, P < 0.01, 48 h) and tumour necrosis factor α (3.45 ± 0.79 vs 2.44 ± 0.39 pg/mL, P < 0.05, 24 h; 4.60 ± 0.57 vs 2.50 ± 0.37 pg/mL, P < 0.01, 48 h) than those of HPD.

CONCLUSION

CD, but not HPD, contained more bacterial contamination, increased monocyte apoptosis in a PKC-δ-dependent manner and induced more cell inflammation. These findings suggest that impurity of dialysis fluid may be an important determinant of the elevated inflammation seen in CD-treated patients.

Complement receptor 1 gene polymorphism and cardiovascular disease in dialyzed end-stage renal disease patients

Inflammation plays an important role in cardiovascular disease (CVD). The complement system is a critical component of innate and acquired immunity. We investigated whether the polymorphisms in the complement receptor 1 (CR1) gene are associated with CVD in end-stage renal disease (ESRD) patients. The study groups of 1200 patients with ESRD, 360 patients with type 2 diabetes and 924 healthy individuals were genotyped. The GG genotype of the C5507G polymorphism was significantly more frequent in ESRD patients with CVD than in patients without CVD and controls (odds ratio [OR] = 3.44, 95% confidence interval [CI] = 2.23-5.3, and OR = 5.46, 95% CI = 3.72-8.0, respectively). The GG genotype was observed in 62% of patients with a history of myocardial infarction. The frequency of the G allele was also higher in patients with CVD (OR = 2.24, 95% CI = 1.93-2.61 vs controls, and OR = 1.97, 95% CI = 1.63-2.36 vs patients without CVD). In the multivariate logistic regression analysis the carrier status of G allele of C5507G polymorphism was an independent risk factor of CVD in ESRD patients (p < 0.001). In conclusion, our results suggest strong association between the CR1 gene polymorphism and CVD in ESRD patients.

C-reactive Protein Is a Strong Predictor of Mortality in Hemodialysis Patients

BACKGROUND

To establish the baseline cutoff value of C-reactive protein (CRP) that would predict increased overall and cardiovascular mortality in patients with end-stage renal disease (ESRD).

METHODS

A cohort of 270 prevalent hemodialysis patients treated at Rijeka University Hospital was eligible for the study. Monthly CRP measurements were performed for three consecutive months. Only the patients with CRP values varying <20% were included (n=256). During the follow-up, 24 patients were transplanted and therefore excluded from the analysis. The CRP cutoff point of 6.2 mg/L was established by Receiver Operating Characteristic curve. The patients were divided into four groups according to their CRP values. Group 1 included 80 (34.5%) patients with CRP <3.0 mg/L, group 2 included 23 (9.9%) patients with CRP 3.0-6.1 mg/L, group 3 consisted of 18 (7.7%) patients with CRP 6.2-10.0 mg/L, and group 4 included 111 (47.9%) patients with CRP >10.0 mg/L. The survival was evaluated by Kaplan-Meier curve.

RESULTS

During the two-year follow-up, 59 patients died. The major cause of death was cardiovascular disease (64%). Significantly higher overall and cardiovascular mortality was observed in group 3 when compared with groups 1 and 2 (chi2=11.97; P < 0.001) and in group 4 when compared with groups 1 and 2 (chi2=14.40; P<0.001). Compared with survivors, non-survivors had a higher median CRP value (19.0 [1.5-99.7] mg/L vs. 2.3 [0.1-49.1] mg/L, respectively; P<0.001).

CONCLUSION

Serum concentration of CRP above 6.2 mg/L is a strong predictor of overall and cardiovascular mortality in patients with ESRD.

Effects of zinc supplementation on serum zinc and C-reactive protein concentrations in hemodialysis patients

OBJECTIVE

We examined the effects of zinc supplementation on serum zinc and C-reactive protein concentrations in hemodialysis patients.

DESIGN

This was a randomized, double-blinded, placebo-controlled clinical trial.

SETTING

This study was conducted at the Shahid Faghihi and Namazi Dialysis Centers in Shiraz, Iran.

PATIENTS

Fifty-five hemodialysis patients (32 men and 23 women) participated after meeting the following criteria: zinc deficiency, treated for a minimum of 6 months; no record of hospitalizations in the preceding 3 months; and hemodialysis treatment 2 to 3 times per week.

INTERVENTION

Patients were randomly divided into two groups. The zinc supplementation group (n=28) received a 220-mg zinc sulfate capsule, and the control group (n=27) received a placebo capsule (220 mg corn starch), for 42 days.

MAIN OUTCOME MEASURES

Fasting, predialysis serum samples were collected on days 0 and 42 to determine serum zinc and C-reactive protein levels.

RESULTS

After supplementation, subjects in the zinc-supplemented group showed significant increases in serum zinc concentrations, from 57.4+/-2.4 microg/dL SEM on day 0 to 88.4+/-4.8 microg/dL SEM on day 42. Serum C-reactive protein concentrations were initially high among subjects in the control (15.1+/-3.9 mg/L SEM) and zinc-supplemented (13.5+/-3.8 mg/L SEM) groups. Serum C-reactive protein concentrations in the control group increased throughout the study period, but did not reach statistical significance. A progressive decrease in serum C-reactive protein concentrations was observed in the zinc-supplemented group from the beginning (13.5+/-3.8mg/L SEM) to the end (10.5+/-3.5mg/L SEM) of the study, but this event was not significant.

CONCLUSION

Zinc supplementation intake may cause an increase in serum zinc concentrations, leading to a decrease of inflammation in hemodialysis patients.

Cytokine (IL-10 -1082 and -819) and chemokine receptor (CCR2 and CCR5) gene polymorphism in North Indian patients with end-stage renal disease

End-stage renal disease (ESRD) is associated with the inflammatory state characterized by infiltrating macrophages/lymphocytes, a major source of cytokines and chemokines. This study examined the role of genetic polymorphisms in cytokine, IL-10, and chemokine receptors, CCR2 and CCR5, with susceptibility to ESRD. Polymorphisms in IL-10 (-1082 G/A, PCR-RFLP; -819 C/T, ARMS-PCR), CCR2 (Val/Ile, PCR-RFLP), and CCR5Delta32 were detected in 184 ESRD patients and 180 controls. Our results demonstrated a significant difference in genotype frequencies of IL-10 -1082G/A (p<0.001), IL-10 -819C/T (p=0.007), and CCR2Val/Ile (p=0.033) between ESRD patients and controls. However, only low-producing genotype AA of IL-10 -1082G/A showed significantly threefold higher risk for all ESRD patients (odds ratio [OR]=3.164, 95%CI=1.74-5.72) as well as patients with only inflammatory causes of renal diseases (OR=2.979, 95%CI=1.61-5.52). No risk was seen in variant genotype of other genes. The genotypic frequencies of CCR5Delta32 were comparable in patients and controls (p=0.203). In haplotype analysis, A-T haplotype (low producer) of IL-10 showed 1.7-fold risk (p>0.05). No risk was seen for CCR2 and CCR5 haplotypes. The AA genotype of IL-10 -1082G/A polymorphism was associated with increased susceptibility to ESRD. This study implies the basis for defined antiinflammatory approaches to impede renal disease progression.

Circulating bacterial-derived DNA fragments and markers of inflammation in chronic hemodialysis patients

BACKGROUND AND OBJECTIVES

Bacterial-derived DNA fragments (BDNAs) have been shown to be present in dialysis fluid, to pass through dialyzer membranes, and to induce IL-6 (IL-6) in mononuclear cells. The present study aimed at assessing the eventual presence of BDNAs in the blood of hemodialysis (HD) patients and if this is associated with markers of chronic inflammation.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Fifty-eight HD patients and 30 controls were included in the study. A blood sample was collected from a peripheral vein and from the central venous catheter (CVC) or the arteriovenous fistula (AVF) and examined for presence of BDNAs by 16S rRNA gene PCR amplification, bacterial growth, and measurement of C-reactive protein and IL-6. Thirty minutes after the start of HD, a sample of dialysis fluid was collected before the entry into and at the exit of the dialyzer and examined for presence of BDNAs.

RESULTS

Controls had negative blood cultures and absence of blood BDNAs. All HD patients had negative blood cultures, but in 12 (20.7%), BDNAs were present in the whole blood. In five of the latter, BDNAs were also found in the dialysis fluid. C-reactive protein serum levels (mg/L) were significantly higher in patients with than in those without BDNAs. Likewise, IL-6 serum levels (pg/ml) were significantly higher in patients with BDNA than in those without.

CONCLUSIONS

Circulating BDNAs are associated with higher levels of C-reactive protein and IL-6 in HD patients.

Nutritional and anti-inflammatory interventions in chronic heart failure

Currently, there are 5 million individuals with chronic heart failure (CHF) in the United States who have poor clinical outcomes, including high death rates. Observational studies have indicated a reverse epidemiology of traditional cardiovascular risk factors in CHF; in contrast to trends seen in the general population, obesity and hypercholesterolemia are associated with improved survival. The temporal discordance between the overnutrition (long-term killer) and undernutrition (short-term killer) not only can explain some of the observed paradoxes but also may indicate that malnutrition, inflammation, and oxidative stress may play a role that results in protein-energy wasting contributing to poor survival in CHF. Diminished appetite or anorexia and nutritional deficiencies may be both a cause and a consequence of this so-called malnutrition-inflammation-cachexia (MIC) or wasting syndrome in CHF. Neurohumoral activation, insulin resistance, cytokine activation, and survival selection-resultant genetic polymorphisms also may contribute to the prominent inflammatory and oxidative characteristics of this population. In patients with CHF and wasting, nutritional strategies including amino acid supplementation may represent a promising therapeutic approach, especially if the provision of additional amino acids, protein, and energy includes nutrients with anti-inflammatory and antioxidant properties. Regardless of the etiology of anorexia, appetite-stimulating agents, especially those with anti-inflammatory properties such as megesterol acetate or pentoxyphylline, may be appropriate adjuncts to dietary supplementation. Understanding the factors that modulate MIC and body wasting and their associations with clinical outcomes in CHF may lead to the development of nutritional strategies that alter the pathophysiology of CHF and improve outcomes.

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 of interleukin (IL)-4 intron-3 and IL-6 -174 G/C gene polymorphism with susceptibility to end-stage renal disease

Earlier studies suggest that end-stage renal disease (ESRD) is associated with inflammatory state and have become a major cause of morbidity and mortality worldwide. This study speculated the role of interleukins (IL)-2, -4, and -6 cytokines gene polymorphism with risk of susceptibility to ESRD. Polymorphism in IL-2 (-330 T/G, polymerase chain reaction [PCR]-restriction fragment length polymorphism), IL-4 (intron-3, variable number of tandem repeat, variable number tandem repeats analysis), and IL-6 (-174 G/C, amplification refractory mutation system, i.e. ARMS-PCR) were genotyped in 193 ESRD patients and 180 controls. Significant difference was observed in genotype frequencies of IL-4 and IL-6 between ESRD patients and control group (p<0.001 and p=0.032, respectively). Patients had higher frequency of homozygous B2B2 genotype (IL-4) than controls (62.7% vs 46.7) and GG genotype of IL-6 (73.1% vs 60.6%). The genotypic frequencies of IL-2 were comparable in patients and controls (p=0.102). Significant association of IL-4 was also observed in patients with glomerulonephritis (p=0.001). Combination of low IL-4 and high IL-6 genotypes were significantly associated with ESRD showing the highest risk, i.e. >threefolds risk (odds ratio=3.48, 95%CI=1.88-6.42; p < 0.001) among the four possible combinations taking high IL-4 and low IL-6 as reference. Our study suggests that polymorphism in IL-4 and IL-6 may be associated with susceptibility to ESRD. Further, combined analysis implicated a higher risk in ESRD patients with low IL-4 and high IL-6 producing genotypes. This study provided the basis for defined anti-inflammatory approaches to limit renal disease progression.

The kidney disease wasting: Inflammation, oxidative stress, and diet-gene interaction

The 350,000 maintenance hemodialysis (MHD) patients in the United States have an unacceptably high mortality rate of >20%/year. Almost half of all deaths are assumed to be cardiovascular. Markers of kidney disease wasting (KDW) such as hypoalbuminemia, anorexia, body weight and fat loss, rather than traditional cardiovascular risk factors, appear to be the strongest predictors of early death in these patients. The KDW is closely related to oxidative stress (SOX). Such SOX markers as serum myeloperoxidase are associated with pro-inflammatory cytokines and poor survival in MHD patients. Identifying the conditions that modulate the KDW/SOX-axis may be the key to improving outcomes in MHD patients. Dysfunctional lipoproteins such as a higher ratio of the high-density lipoprotein inflammatory index (HII) may engender or aggravate the KDW, whereas functionally intact or larger lipoprotein pools, as in hypercholesterolemia and obesity, may mitigate the KDW in MHD patients. Hence, a reverse epidemiology or "bad-gone-good" phenomenon may be observed. Diet and gene and their complex interaction may lead to higher proportions of pro-inflammatory or oxidative lipoproteins such as HII, resulting in the aggravation of the SOX and inflammatory processes, endothelial dysfunction, and subsequent atherosclerotic cardiovascular disease and death in MHD patients. Understanding the factors that modulate the KDW/SOX complex and their associations with genetic polymorphism, nutrition, and outcomes in MHD patients may lead to developing more effective strategies to improve outcomes in this and the 20 to 30 million Americans with chronic disease states such as individuals with chronic heart failure, advanced age, malignancies, AIDS, or cachexia.

Interleukin-1beta and receptor antagonist (IL-1Ra) gene polymorphisms and the prediction of the risk of end-stage renal disease

Cytokines play an important role in the pathogenesis of kidney disease and its progression to end-stage renal disease (ESRD). Inflammation is regulated by the genes of the interleukin 1 (IL-1) gene cluster. Therefore, it was hypothesized that a polymorphism in this gene cluster may be associated with the risk of ESRD. Polymorphisms in the IL-1 gene cluster were examined in a cohort of 222 ESRD patients and 206 controls of similar ethnicity. These individuals were genotyped for IL-1 beta (promoter -511 and exon-5 +3953) genes and a variable number of tandem repeats (VNTR) in the IL-1 receptor antagonist gene (IL-1Ra). There was significant difference in genotype frequencies between ESRD patients and control group for IL-1beta (promoter region and exon-5) and IL-1Ra gene polymorphism (p < 0.001, 0.006 and < 0.001, respectively). A significant difference was observed in IL-1Ra for 1/1 (410/410) and 1/2 (410/240) genotypes, and the risk for ESRD was higher in those carrying the 1/1 genotype (p = 0.014, OR = 1.692, and p < 0.001, OR = 0.163). Also identified was a novel, rare allele of a single copy of 86 bp in ESRD patients as compared with the controls. The haplotype 'T-E2-1' frequency distribution between patients and controls revealed greater than threefold risk (p = 0.001, OR = 3.572, 95% CI = 1.589-8.032). Genetic linkage between the IL-1beta promoter region and exon-5 and between the IL-1beta promoter and IL-1Ra of IL-1 gene demonstrated a strong association among the variants in controls (D' = 0.42, p < 0.001, and D' = 0.39, p=0.001). Thus, the three polymorphisms within the IL-1 cluster are associated with ESRD. This finding is perhaps one of the strongest associations between genotype and ESRD reported, and it suggests that the IL-1 gene cluster affects the risk of development of ESRD.

New insights on inflammation in chronic kidney disease–genetic and non-genetic factors

Cardiovascular disease (CVD) remains the major cause of morbidity and mortality in chronic kidney disease (CKD). As traditional risk factors cannot alone explain the unacceptable high prevalence and incidence of CVD in this population, inflammation (which is 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 (CRP) has been shown to independently predict mortality in CKD patients. The causes of the highly prevalent state of inflammation in CKD are multiple and include factors such as volume overload, co-morbidity, intercurrent clinical events, the dialysis procedure per se as well as genetic factors. Indeed, multiple cytokine DNA polymorphisms may affect the inflammatory state, the clinical phenotype as well as outcome in this patient population.

Protecting the endothelium: a new focus for management of chronic kidney disease

It is being increasingly recognized that cardiovascular disease (CVD) and its complications are the most important cause of morbidity and mortality in patients with chronic kidney disease (CKD) and dialysis patients. If outcomes for these patients are to be improved, therapeutic strategies at all stages of CKD will have to target the etiologies and mechanisms that lead to CVD. In this review, we focus on the central role of endothelial dysfunction as the critical precursor of CVD. We argue that a better understanding of endothelial dysfunction by nephrologists and dialysis physicians is necessary if there is to be success in limiting the CVD epidemic that kills and maims our patients. The extensive studies to explain the high prevalence of vascular disease in patients with CKD have shown the close relationship among endothelial dysfunction, inflammation, and atherosclerosis. The pathogenesis starts with endothelial cell injury from any of many possible causes, and strategies to reduce the burden of CVD in uremic and dialysis patients must be directed at restoring normal endothelial function or, at the least, preventing aggravation of endothelial damage. At the center of the exploration of endothelial dysfunction and atherosclerosis are oxidative stress and inflammation. Of these, which is the chicken and which is the egg is unknown, but in the setting of uremia, endothelial injury because of free radical, oxidative stress is likely to precede inflammation. The issues raised here are highly complex and most renal practitioners may not have been adequately exposed to the background research underlying current thinking of the pathogenesis of vascular disease. Clearly, progress in management of CVD in patients with CKD will require collaboration with experts in the research and treatment of vascular disease. Nephrologists seeking optimum outcomes for patients with CKD will need to become "endotheliologists" or, at the least, subscribe to a mission "to protect the endothelium."

Effect of Intravenous Ascorbic Acid in Hemodialysis Patients With EPO-Hyporesponsive Anemia and Hyperferritinemia

BACKGROUND

Although erythropoietin (EPO)-hyporesponsive anemia in hemodialysis patients most commonly results from iron deficiency, the contributory role of chronic inflammation and oxidative stress in its pathogenesis is poorly understood. We conducted an open-label prospective study to assess the effect of vitamin C, an antioxidant, on EPO-hyporesponsive anemia in hemodialysis patients with unexplained hyperferritinemia.

METHODS

Forty-six of 262 patients in an inner-city hemodialysis center met the inclusion criteria (administration of intravenous iron and EPO for > or = 6 months at a dose > or = 450 U/kg/wk, average 3-month hemoglobin [Hb] level < or = 11.0 g/dL [< or = 110 g/L], ferritin level > or = 500 ng/mL (microg/L), and transferrin saturation [TSAT] < or = 50%). Patients were excluded if they had a clear explanation for the EPO hyporesponsiveness. Four patients refused to participate. The remaining patients were randomly assigned; 20 patients to receive standard care and 300 mg of intravenous vitamin C with each dialysis session (group 1) and 22 patients to receive standard care only (group 2). Study duration was 6 months. During the study, 1 patient from group 1 was removed (upper gastrointestinal bleeding) from final analysis. Monthly assessment included Hb level, mean corpuscular volume, iron level, iron-binding capacity, ferritin level, TSAT, and Hb content in reticulocytes. In addition, biointact parathyroid hormone, aluminum, C-reactive protein (CRP), and liver enzymes were measured every 3 months.

RESULTS

Age, sex, race, and time on dialysis therapy were similar in both groups. At 6 months, Hb levels significantly increased from 9.3 to 10.5 g/dL (93.0 to 105.0 g/L) in group 1, but not group 2 (9.3 to 9.6 g/dL [93.0 to 96.0 g/L]; P = 0.0001). Similarly, TSAT increased from 28.9% to 37.3% in group 1, but not group 2 (28.7% to 29.3%; P = 0.0001). EPO dose (477 to 429 versus 474 to 447 U/kg/wk), iron-binding capacity (216 to 194 versus 218 to 257 microg/dL [38.7 to 34.7 versus 39 to 46 micromol/L]), and CRP level (2.8 to 0.9 versus 2.8 to 2.2 mg/dL) decreased significantly in group 1, but not in controls. Changes in Hb content in reticulocytes and ferritin level also were statistically significant in group 1. There was no change in biointact parathyroid hormone levels. Although serum iron levels and intravenous iron doses changed within each group, changes were equal between the 2 groups.

CONCLUSION

In hemodialysis patients with refractory anemia and hyperferritinemia, vitamin C improved responsiveness to EPO, either by augmenting iron mobilization from its tissue stores or through antioxidant effects.

Gene Polymorphism Association Studies in Dialysis: The Nutrition-Inflammation Axis

Although traditional risk factors for cardiovascular disease are common in dialysis patients, they alone cannot explain the unacceptably high prevalence of vascular disease in this patient group. Much recent interest has therefore focused on the role of various nontraditional cardiovascular risk factors, such as inflammation, wasting, obesity, vascular calcification, and oxidative stress. In addition, genetic factors such as single nucleotide polymorphisms (SNPs) may significantly influence the immune response, the levels of inflammatory markers and body composition, as well as the prevalence of vascular calcification in this patient group. While genetic variations in the tumor necrosis factor (TNF)-alpha-308 and interleukin (IL)-10 -1082 SNPs seem to be consistently associated with adverse clinical outcome in end-stage renal disease (ESRD) patients, the results regarding genetic variations in the IL-6 gene have been conflicting. To elucidate the respective role of DNA polymorphisms in the IL-6 and C-reactive protein (CRP) genes, as well as genes that encode vascular calcification inhibitors (such as fetuin-A, matrix Gla protein, and osteoprotegerin), sufficiently powered studies are needed in which both the protein product and the specific phenotype are determined. In addition, polymorphisms in genes related to body composition may be excellent candidates for analysis in the ESRD population, since nutritional parameters are strongly associated with adverse events in these patients. It seems conceivable that in the future, prognostic or predictive multigene DNA assays (which allow a simultaneous and rapid assessment of multiple genetic variants) will provide nephrologists with a more precise approach for the identification of "high-risk" ESRD patients and the development of accurate individualized treatment strategies.