Inflammatory syndrome in patients on hemodialysis

Citrate-Buffered Dialysis Solution (Citrasate) Allows Avoidance of Anticoagulation During Intermittent Hemodiafiltration-At the Cost of Decreased Performance and Systemic Biocompatibility

Reportedly, citrate-based dialysis solution enables heparin dose tapering or even complete exclusion, particularly in postdilution hemodiafiltration (HDF). The aim of the study was to verify this strategy in predilution setting and to assess its short-term safety, efficacy, and biocompatibility. Ten regular hemodialysis patients were assigned to predilution HDF on acetate- and citrate-based dialysis solutions (0.8 mmol/l trisodium citrate) at random order. Acetate HDF was performed using routine dose of heparin while citrate HDF was heparin free. Plasma calcium, thrombin-antithrombin complexes (TAT), and citrate levels were measured at 0, 30, 60, 120, and 240 min. Following each session, a semiquantitative dialyzer clotting score (DCT 1-5) was assessed and HDF adequacy was determined as spKt/V. Statistical relevance was tested by ANOVA with pP < 0.05 held significant, data are given as means ± standard deviations. All sessions were accomplished successfully, premature termination or circuit re-setting was not necessary. However, DCT was significantly higher in citrate-HDF compared to acetate-HDF regimen (3.4 ± 0.65 and 1.8 ± 0.79, respectively, P = 0.002) as well as TAT generation rate (increase per session by factor 11.0 ± 8.43 and 2.1 ± 1.26, respectively, P = 0.004 between regimens). Ionized calcium declined only by the end of citrate-HDF (from 1.09 ± 0.086 to 0.99 ± 0.030 mmol/L, P = 0.002) yet without accompanying clinical symptoms. Systemic citrate levels increased along the citrate-HDF session but stayed an order of magnitude below concentrations needed to establish citrate anticoagulation (peak at 0.276 ± 0.112 mmol/L). Dialysis adequacy estimated by spKt/V was found lower in citrate-HDF vs. acetate-HDF (1.48 ± 0.163 and 1.58 ± 0.165, respectively, P = 0.006). Although predilution HDF using citrate-based dialysate is feasible without heparin, both dialysis adequacy and biocompatibility is significantly compromised. Therefore, this approach can be adopted for a single procedure but is not acceptable on a regular basis.

Liberation From Renal Replacement Therapy After Cadaveric Liver Transplantation

Background

Renal failure requiring renal replacement therapy (RRT) is common in patients with end-stage liver disease (ESLD) and is associated with worse outcomes following liver transplantation (LT). We investigated the factors associated with liberation from posttransplant RRT and studied the impact of RRT on patient and graft outcomes.

Methods

A 5-year retrospective study of ESLD patients who received pretransplant RRT was conducted. Variables associated with liberation from RRT at 30 days and at 1-year posttransplant were analyzed. We used propensity matching to compare patient and graft outcomes in the study cohort to those of a control group who underwent LT but not pretransplant RRT.

Results

Sixty-four patients were included in the study. Twenty-four (38%) were liberated from RRT at 30 days posttransplant. Duration of pretransplant RRT (odds ratio [OR], 0.94; 95% confidence interval [CI], 0.89-0.98) and severe postreperfusion syndrome (OR, 0.26; 95% CI, 0.08-0.87) were significantly associated with continued RRT at 1-month posttransplant. At one year, 34 (53%) patients were liberated from RRT. Age was significantly associated with lack of liberation from RRT (OR, 0.933; 95% CI, 0.875-0.995). Compared with propensity matched controls, patients who received RRT pretransplant had worse graft and patient survival at 1 year (52% vs 82%; P = 0.01, and 53% vs 83%; P = 0.003, respectively).

Conclusions

In ESLD patients who received pretransplant RRT, one third were liberated from RRT at 1 month, and half at 1 year. Longer duration of pretransplant RRT, postreperfusion syndrome, and older age were associated with lower likelihood of liberation from RRT. Patients who required pretransplant RRT had worse graft and patient survivals compared to matched patients who did not require RRT. Patients who were liberated from RRT post-LT had similar outcomes to patients who never required pre-LT RRT.

Renal transplantation-related risk factors for the development of uterine adenomatoid tumors

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We analyzed the epidemiological factors for clinical manifestations of uterine adenomatoid tumors.

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Renal transplantation with immunosuppression therapy is risk factor for the development of uterine adenomatoid tumors.

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The length of time on dialysis is risk factor for the development of uterine adenomatoid tumors.

Lower C-reactive protein and better hemodialysis survival are associated with regular exercise activity: Longitudinal outcomes from the ACTIVE-ADIPOSE special study

Introduction Cross-sectional and longitudinal studies in the general population have shown that a physically active lifestyle may have anti-inflammatory properties, but evidence from studies conducted with maintenance hemodialysis (HD) patients is limited. Methods A multicenter prospective cohort of 755 HD participants aged 20-92 was evaluated in a USRDS special study 2009-2013. Kilocalories/week (kcal/week) of leisure time physical activity (LTPA) was estimated from the Minnesota Leisure Time Activity questionnaire. Predialysis serum samples were obtained concurrent with LTPA report date. Generalized estimating equations (GEE) examined association of participants' LTPA and log-normalized CRP across 24 months. Cox proportional hazards models investigated LTPA and survival over a median follow-up of 718 days. Findings Baseline median CRP concentration was lower for participants with 500+ kcal/week LTPA vs. those with <500 kcal/week LTPA (3.4 mg/L vs. 4.6 mg/L; P = 0.03). Participants who reported lower LTPA (<500 kcal/week) at both baseline and 12 months had a borderline significant increase in CRP concentration (within-group change 4.8 [1.9-10.4] to 5.8 [1.6-15.7]; P = 0.08). Lower LTPA was associated with higher log CRP over 24 months in adjusted GEE analyses (β coefficient = 0.16 [95% CI 0.02-0.31]; P = 0.03). 67/364 (18%) and 43/391 (11%) deaths occurred, respectively, among participants reporting <500 vs. 500+ kcal/week LTPA [adjusted mortality hazard ratio 1.63 (CI, 1.07, 2.47)]. Discussion The data suggest that increased estimated levels of LTPA, a physical activity/exercise opportunity widely applicable to HD patients, may be associated with lower CRP concentration as well as better survival outcome.

Detection of autonomic dysfunction in hemodialysis patients using the exercise treadmill test: the role of the chronotropic index, heart rate recovery, and R-R variability

OBJECTIVE

To evaluate the ability of different parameters of exercise treadmill test to detect autonomic dysfunction in hemodialysis patients.

METHODS

Cross-sectional study involving hemodialysis patients and a control group. Clinical examination, blood sampling, echocardiogram, 24-hour Holter, and exercise treadmill test were performed. A ramp treadmill protocol symptom-limited with active recovery was employed.

RESULTS

Forty-one hemodialysis patients and 41 controls concluded the study. There was significant difference between hemodialysis patients and controls in autonomic function parameters in 24h-Holter and exercise treadmill test. Probability of having autonomic dysfunction in hemodialysis patients compared to controls was 29.7 at the exercise treadmill test and 13.0 in the 24-hour Holter. Chronotropic index, heart rate recovery at the 1st min, and SDNN at exercise were used to develop an autonomic dysfunction score to grade autonomic dysfunction, in which, 83% of hemodialysis patients reached a scoring ≥2 in contrast to 20% of controls. Hemodialysis was independently associated with either altered chronotropic index or autonomic dysfunction scoring ≥2 in every tested model (OR=50.1, P=0.003; and OR=270.9, P=0.002, respectively, model 5).

CONCLUSION

The exercise treadmill test was feasible and useful to diagnose of the autonomic dysfunction in hemodialysis patients. Chronotropic index and autonomic dysfunction scoring ≥2 were the most effective parameters to differentiate between hemodialysis patients and controls suggesting that these variables portrays the best ability to detect autonomic dysfunction in this setting.

Body composition and survival in dialysis patients: results from an international cohort study

BACKGROUND AND OBJECTIVES

High body mass index appears protective in hemodialysis patients, but uncertainty prevails regarding which components of body composition, fat or lean body mass, are primarily associated with survival.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data between April 2006 and December 2012 were extracted from the Fresenius Medical Care Europe subset of the international MONitoring Dialysis Outcomes initiative. Fresenius Medical Care Europe archives a unique repository of predialysis body composition measurements determined by multifrequency bioimpedance (BCM Body Composition Monitor). The BCM Body Composition Monitor reports lean tissue indices (LTIs) and fat tissue indices (FTIs), which are the respective tissue masses normalized to height squared, relative to an age- and sex-matched healthy population. The relationship between LTI and FTI and all-cause mortality was studied by Kaplan-Meier analysis, multivariate Cox regression, and smoothing spline ANOVA logistic regression.

RESULTS

In 37,345 hemodialysis patients, median (25th-75th percentile) LTI and FTI were 12.2 (10.3-14.5) and 9.8 (6.6-12.4) kg/m(2), respectively. Median (25th-75th percentile) follow-up time was 266 (132-379) days; 3458 (9.2%) patients died during follow-up. Mortality was lowest with both LTI and FTI in the 10th-90th percentile (reference group) and significantly higher at the lower LTI and FTI extreme (hazard ratio [HR], 3.37; 95% confidence interval [95% CI], 2.94 to 3.87; P<0.001). Survival was best with LTI between 15 and 20 kg/m(2) and FTI between 4 and 15 kg/m(2) (probability of death during follow-up: <5%). When taking the relation between both compartments into account, the interaction was significant (P=0.01). Higher FTI appeared protective in patients with low LTI (HR, 3.37; 95% CI, 2.94 to 3.87; P<0.001 at low LTI-low FTI, decreasing to HR, 1.79; 95% CI, 1.47 to 2.17; P<0.001 at low LTI-high FTI).

CONCLUSIONS

This large international study indicates best survival in patients with both LTI and FTI in the 10th-90th percentiles of a healthy population. In analyses of body composition, both lean tissue and fat tissue compartments and also their relationship should be considered.

Decreased number of CD14+TLR4+ monocytes and their impaired cytokine responses to lipopolysaccharide in patients with chronic kidney disease

This study aimed to examine the number of circulating Toll-like receptor 4 (TLR4) + CD14+ monocytes in patients with different stages of chronic kidney disease (CKD), their responses to lipopolysaccharide (LPS), and to explore the potential association of the number of TLR4+CD14+ monocytes with clinical laboratory measures. The numbers of TLR4+CD14+, LPS-stimulated TNF-α+CD14+ and interleukin (IL)-6+CD14+ monocytes were determined by flow cytometry in 9 patients with stage 3 CKD, 11 with stage 4 CKD, 16 with stage 5 CKD, and 19 healthy controls (HCs). Their laboratory tests were performed by routine methods and the potential association among these measures was analyzed by Pearson's correlation analysis. The numbers of CD14+, CD14+TLR4+, LPSstimulated TNF-α+CD14+ and IL-6+CD14+ monocytes in patients with CKD were significantly less than those of HCs (all P<0.05), and were negatively associated with patient disease severity. The number of CD14+TLR4+ monocytes was positively correlated with estimated glomerular filtration rate (eGFR, P<0.001) and the levels of hematocrit (P<0.01), but negatively correlated with the levels of blood urine nitrogen, serum creatinine, and C-reactive protein (P<0.001 for all), in the CKD patients. Our data indicate that significant reduction in the number of TLR4+ monocytes and their impaired responses to LPS may be associated with the progression of CKD in Chinese patients.

Evaluation of a polynephron dialysis membrane considering new aspects of biocompatibility

PURPOSE

The biocompatibility of dialyzers may influence the inflammatory state of hemodialysis patients. This study compares the effect of a high-flux polynephron membrane with other high-flux membranes, helixone and polyamide, on some inflammation biomarkers based on the analysis of circulating mononuclear cells (MC).

METHODS

The study included 47 patients on hemodialysis with helixone and polyamide; 9 formed the control group, without changes in their dialyzers throughout the study, and 38 formed the intervention group, in which their dialyzers were replaced by polynephron. In both groups, blood samples were taken at the beginning of the study before and after hemodialysis session, and at the end of the study 4 months later. In each extraction, biochemical parameters were determined, and MC isolated using Ficoll gradient. Production of reactive oxygen species and the percentage of activated MC (CD14+CD16+) were measured by flow cytometry, and protein levels of heat-shock proteins (Hsp70/Hsp90) studied by Western blot.

RESULTS

After 1 hemodialysis session with different membranes, no significant differences were observed in the different parameters considered. After 4 months of dialysis with polynephron, a significant reduction in the percentage of CD14+CD16+ and in the β2-microglobulin reduction ratio were found, with respect to helixone and polyamide, without changes in the other parameters analyzed.

CONCLUSIONS

The use of polynephron for 4 months reduces the percentage of CD14+CD16+ compared to helixone and polyamide, suggesting a better profile regarding activation of the inflammatory response. These findings could be explained by a better biocompatibility or an increased reduction of medium-sized toxic molecules.

Pro-inflammatory cytokines and leukocyte oxidative burst in chronic kidney disease: culprits or innocent bystanders?

BACKGROUND

Pro-inflammatory cytokines are elevated in chronic kidney disease (CKD), a condition characterized by microinflammation with oxidative stress as key feature. However, their role in the inflammatory response at uraemic concentrations has not yet been defined. In this study, the contribution of cytokines on induction of leukocyte oxidative stress was investigated.

METHODS

Whole blood from healthy donors was incubated with 20-1400 pg/mL TNFα, 5-102.8 pg/mL IL-6, 20-400 pg/mL IL-1β and 75-1200 pg/mL IL-18 separately or in combination. Oxidative burst was measured, at baseline and after stimulation with fMLP (Phagoburst™). The effect of the TNFα blocker, adalimumab (Ada), was evaluated on TNFα-induced ROS production. Finally, the association between TNFα and the composite end point all-cause mortality or first cardiovascular event was analysed in a CKD population stage 4-5 (n = 121).

RESULTS

While interleukin (IL)-6, IL-1β and IL-18 alone induced no ROS activation of normal leukocytes, irrespective of concentrations, TNFα induced ROS activation at baseline (P < 0.01) and after fMLP stimulation (P < 0.05), but only at uraemic concentrations in the high range (400 and 1400 pg/mL). A similar pattern was observed with all cytokines in combination, but already at intermediate uraemic concentrations (all P < 0.05, except for monocytes after fMLP stimulation: n.s.), suggesting synergism between cytokines. ROS production induced by TNFα (400 pg/mL) and the cytokine combination was blocked with Ada. Uraemia-related oxidative stress in leukocytes of haemodialysis patients was however not blocked by Ada. In patients, TNFα was not associated to adverse events (HR: 1.52, 95% CI 0.81-2.85, P = 0.13).

CONCLUSION

Among several pro-inflammatory cytokines, TNFα alone was pro-oxidative but only at high-range uraemic concentrations. Adding a TNFα blocker, Ada, blocked this ROS production, but not the oxidative stress in blood samples from haemodialysis patients, suggesting that other uraemic toxins than TNFα are more crucial in this process. However, the lack of association between TNFα and mortality suggests that the role of TNFα-linked oxidative stress is limited.

Therapeutic C3 inhibitor Cp40 abrogates complement activation induced by modern hemodialysis filters

Approximately 350,000 individuals in the United States rely on maintenance hemodialysis treatment because of end-stage renal disease. Despite improvements in dialysis technology, the mortality rate for patients treated with maintenance dialysis is still exceptionally high, with a 5-year survival rate of only 35%. Many patients succumb to conditions resulting at least in part from the chronic induction of inflammation. Among the triggers of inflammation, the complement system is of particular importance, being a well-appreciated mediator of inflammatory processes that is involved in many pathologic states. Here we used a refined pre-clinical model of hemodialysis in cynomolgus monkeys to confirm that even modern, polymer-based hemodialysis filters activate complement and to evaluate the potential of Cp40, a peptidic C3 inhibitor, to attenuate hemodialysis-induced complement activation. Our data show marked induction of complement activation even after only a single session of hemodialysis. Importantly, complete inhibition of complement activation was achieved in response to two distinct Cp40 treatment regimens. Further, we show that application of Cp40 during hemodialysis resulted in increased levels of the anti-inflammatory cytokine IL-10, indicating that Cp40 may be a potent and cost-effective treatment option for attenuating chronic inflammatory conditions in dialysis-dependent patients.

Influence of Polysulphone-Derived Dialysis Membranes on the Interaction of Circulating Mononuclear Cells with the Endothelium

Purpose

Cardiovascular morbidity in hemodialysis (HD) patients may be influenced by the activation of circulating mononuclear cells (MCs) with subsequently increased endothelium interaction. The use of more biocompatible membranes would reduce this monocyte activation. We compare monocyte activation after using two different high-flux polymers, polysulphone and polyethersulphone.

Methods

The first part of the study was done with 10 patients who successively received dialysis for 2 weeks with polysulphone and polyethersulphone. The second part with 30 patients dialyzed for 3 months with polysulphone or polyethersulphone. Blood samples were taken before (pre-HD) and after (post-HD) the first HD session with each membrane to evaluate the effect of a single HD session. To assess acute and chronic effects of membranes, blood samples were taken pre-HD, after 2 weeks (first part of study) and after 3 months (second part of study). MCs were isolated from blood and then incubated with cultured human endothelial cells to evaluate MC adhesion, MC-dependent endothelial toxicity, and endothelial protein expressions of nitric oxide synthase and endothelin-converting enzyme-1 (ECE-1).

Results

One single HD session did not induce any changes. Dialysis for 2 weeks (first part of study) with polyethersulphone reduced MC adhesion to endothelium, cellular toxicity, and ECE-1 protein expression compared to polysulphone or basal conditions. Dialysis for 3 months (second part of study) increased MC adhesion to endothelium, whereas cellular toxicity was decreased with both dialyzers compared to the basal situation.

Conclusions

Although polyethersulphone HD decreased the interaction of MC with the endothelium in short-term experiments, both membranes were comparable in the long-term.

Pretransplant IgG reactivity to apoptotic cells correlates with late kidney allograft loss

Preexisting serum antibodies have long been associated with graft loss in transplant recipients. While most studies have focused on HLA-specific antibodies, the contribution of non-HLA-reactive antibodies has been largely overlooked. We have recently characterized mAbs secreted by B cell clones derived from kidney allograft recipients with rejection that bind to apoptotic cells. Here, we assessed the presence of such antibodies in pretransplant serum from 300 kidney transplant recipients and examined their contribution to the graft outcomes. Kaplan-Meier survival analysis revealed that patients with high pretransplant IgG reactivity to apoptotic cells had a significantly increased rate of late graft loss. The effect was only apparent after approximately 1 year posttransplant. Moreover, the association between pretransplant IgG reactivity to apoptotic cells and graft loss was still significant after excluding patients with high reactivity to HLA. This reactivity was almost exclusively mediated by IgG1 and IgG3 with complement fixing and activating properties. Overall, our findings support the view that IgG reactive to apoptotic cells contribute to presensitization. Taking these antibodies into consideration alongside anti-HLA antibodies during candidate evaluation would likely improve the transplant risk assessment.

Statins in chronic kidney disease and kidney transplantation

HMG-CoA reductase inhibitors (statins) have been shown to improve cardiovascular (CV) outcomes in the general population as well as in patients with cardiovascular disease (CVD). Statins' beneficial effects have been attributed to both cholesterol-lowering and cholesterol-independent "pleiotropic" properties. By their pleiotropic effects statins have been shown to reduce inflammation, alleviate oxidative stress, modify the immunologic responses, improve endothelial function and suppress platelet aggregation. Patients with chronic kidney disease (CKD) exhibit an enormous increase in CVD rates even from early CKD stages. As considerable differences exist in dyslipidemia characteristics and the pathogenesis of CVD in CKD, statins' CV benefits in CKD patients (including those with a kidney graft) should not be considered unequivocal. Indeed, accumulating clinical evidence suggests that statins exert diverse effects on dialysis and non-dialysis CKD patients. Therefore, it seems that statins improve CV outcomes in non-dialysis patients whereas exert little (if any) benefit in the dialysis population. It has also been proposed that dyslipidemia might play a causative role or even accelerate renal injury. Moreover, ample experimental evidence suggests that statins ameliorate renal damage. However, a high quality randomized controlled trial (RCT) and metaanalyses do not support a beneficial role of statins in renal outcomes in terms of proteinuria reduction or retardation of glomerular filtration rate (GFR) decline.

Relationship of galectin-3 to left ventricular geometry and hypertrophy in chronic hemodialysis patients

AIM AND BACKGROUND

Galectin-3 (Gal-3) is used to determine the prognosis of heart failure. Some studies revealed that Gal-3 promoted cardiac hypertrophy but there is no study in which the relationship between Gal-3 and left ventricular hypertrophy (LVH) geometry in patients without diastolic and systolic function impairment has been explored. The aim of the study was to analyze associations between plasma Gal-3 levels, LVH, and LV geometry in maintenance hemodialysis (HD) patients without systolic and diastolic dysfunction.

PATIENTS AND METHODS

The study group included 105 patients (53 women and 52 men)--with an average age of 58.2 ± 12.6 years, treated with HD for an average of 45 ± 32 months--and 60 healthy controls. The Gal-3 and other biochemical parameters were measured and color Doppler echocardiography was performed. For this study LVH was considered present when the LV mass index (LVMI) exceeded 95 g/m(2) in women and 115 g/m(2) in men. Left ventricular geometry was classified into the four groups on the basis of left ventricular mass and relative wall thickness (RWT).

RESULTS

Concentric hypertrophy (CH, 40.9 %, n = 43) was the commonest geometric pattern in our study. The Gal-3 levels in CH patients were not different from the patients with eccentric hypertrophy (EH). Plasma levels of Gal-3 correlated with LVMI (r = 0.617, p < 0.001), parathyroid hormone (PTH, r = 0.408, p < 0.001), uric acid (r = 0.281, p = 0.004), C-reactive protein (CRP, r = 0.412, p < 0.001), and RWT (r = 0.281, p = 0.004) but were inversely correlated with albumin (r = - 0.466, P < 0.001) in the whole group. Plasma levels of Gal-3 were associated with LVMI (r = 0.812, P < 0.001), RWT (r = 0.318, p = 0.001), and CRP(r = 0.381, p < 0.001) in maintenance hemodialysis patients.

CONCLUSION

The Gal-3 level is related to left ventricular hypertrophy and it is independent of left ventricle geometry. The relationship between LVH and Gal-3 might be direct or it may also be inflammation-related.

Guidance cue netrin-1 and the regulation of inflammation in acute and chronic kidney disease

Acute kidney injury (AKI) is a common problem in the hospital setting and intensive care unit. Despite improved understanding, there are no effective therapies available to treat AKI. A large body of evidence strongly suggests that ischemia reperfusion injury is an inflammatory disease mediated by both adaptive and innate immune systems. Cell migration also plays an important role in embryonic development and inflammation, and this process is highly regulated to ensure tissue homeostasis. One such paradigm exists in the developing nervous system, where neuronal migration is mediated by a balance between chemoattractive and chemorepulsive signals. The ability of the guidance molecule netrin-1 to repulse or abolish attraction of neuronal cells expressing the UNC5B receptor makes it an attractive candidate for the regulation of inflammatory cell migration. Recent identification of netrin-1 as regulators of immune cell migration has led to a large number of studies looking into how netrin-1 controls inflammation and inflammatory cell migration. This review will focus on recent advances in understanding netrin-1 mediated regulation of inflammation during acute and chronic kidney disease and whether netrin-1 and its receptor activation can be used to treat acute and chronic kidney disease.

Strategies for the preservation of residual renal function in pediatric dialysis patients

In adults with end-stage renal disease (ESRD), the preservation of residual renal function (RRF) has been shown to be associated with decreased mortality and improved control of complications of chronic kidney disease. However, less is known on the benefits of RRF in the pediatric dialysis population. The purpose of this article is to review the clinical significance of RRF and to discuss strategies for the preservation of RRF in children with ESRD.

Invariant natural killer T cells are depleted in renal impairment and recover after kidney transplantation

BACKGROUND

Altered immune function in patients with renal failure results in both susceptibility to infection and increased inflammatory response. Invariant natural killer T (iNKT) cells are a conserved, immunoregulatory T lymphocyte subset that responds to lipid antigens with near-immediate cytokine production and cytotoxicity. iNKT cells are required for the antibacterial host response. Whether renal failure and renal replacement therapy alter iNKT cell abundance or phenotype has not been investigated.

METHODS

iNKT cells were studied by flow cytometry in the peripheral blood of patients with acute renal failure, chronic haemo- and peritoneal dialysis (PD), chronic kidney disease and after renal transplantation.

RESULTS

A very marked reduction in iNKT lymphocytes was found in acute renal failure before the first haemodialysis (HD) session. iNKT cells were depleted in end-stage renal disease patients receiving either HD or PD. iNKT cell depletion was accentuated after an HD session. Lesser degrees were observed in patients with non-dialysis-dependent chronic kidney disease. CD56 and CD161 NK cell marker expression was decreased in renal impairment. CD56(+) and CD161(+) iNKT cells produced more interferon-γ than negative cells of the same donor. Within the first year after kidney transplantation, the decrease in iNKT cells and their NK cell markers was reverted.

CONCLUSIONS

We describe for the first time that iNKT lymphocytes are reduced in end-stage renal disease and further depleted by HD. iNKT cells are important for early host response including activation of other immune cells and their depletion may contribute to immune dysfunction in renal disease.

Resistance to erythropoiesis-stimulating agents is associated with arterial microcalcification in early hemodialysis patients

The aim of this study was to evaluate the relationship between arterial microcalcification (AMiC) and erythropoiesis-stimulating agents (ESA) hyporesponsiveness in hemodialysis patients. The presence of AMiC was confirmed by pathologic examination of von Kossa-stained arterial specimens acquired during vascular access surgery. We assessed the ESA hyporesponsiveness index (EHRI), defined as the weekly ESA dose per kilogram body weight divided by the hemoglobin level. AMiC was detected in 33 (40.2%) of 82 patients. Patients with diabetes had a higher incidence of AMiC than patients without diabetes. The serum levels of albumin and cholesterol were higher in patients without AMiC than in patients with AMiC. The serum levels of intact parathyroid hormone were lower in patients with AMiC than in patients without AMiC. The serum levels of phosphate and calcium-phosphorus product did not differ between the two groups. The mean EHRI value was higher in patients with AMiC than in patients without AMiC. In multivariate analyses, ESA hyporesponsiveness and diabetes showed a significant association with AMiC. In conclusion, ESA hyporesponsiveness may be a clinical relevant parameters related to AMiC in hemodialysis patients.

Protein-bound uremic toxins: new culprits of cardiovascular events in chronic kidney disease patients

Chronic kidney disease (CKD) has been considered a major risk factor for cardiovascular diseases. Although great advances have recently been made in the pathophysiology and treatment of cardiovascular diseases, CKD remains a major global health problem. Moreover, the occurrence rates of cardiovascular events among CKD patients increase even in cases in which patients undergo hemodialysis, and the mechanisms underlying the so-called “cardiorenal syndrome” are not clearly understood. Recently, small-molecule uremic toxins have been associated with cardiovascular mortality in CKD and/or dialysis patients. These toxins range from small uncharged solutes to large protein-bound structures. In this review, we focused on protein-bound uremic toxins, such as indoxyl sulfate and p-cresyl sulfate, which are poorly removed by current dialysis techniques. Several studies have demonstrated that protein-bound uremic toxins, especially indoxyl sulfate, induce vascular inflammation, endothelial dysfunction, and vascular calcification, which may explain the relatively poor prognosis of CKD and dialysis patients. The aim of this review is to provide novel insights into the effects of indoxyl sulfate and p-cresyl sulfate on the pathogenesis of atherosclerosis.

The prognostic value of time needed on dialysis in patients with delayed graft function

INTRODUCTION

We hypothesize that in patients with delayed graft function (DGF), the need for a longer time needed on dialysis (TND) post-kidney transplant is associated with poorer long-term function and an increase in complications.

METHODS

This was a retrospective chart review involving collaboration between Western University (WU) Renal Transplant Program of London, Ontario and the Saskatchewan renal transplant program (SRTP). A total of 774 patients (567 WU and 207 SRTP) received kidney transplants between 2004 and 2011, of which 83 patients with deceased donor transplants (59 WU and 24 SRTP) developed DGF, defined as the need for dialysis in the first week posttransplant.

RESULTS

Patients with DGF were divided into three groups depending on TND [group 1: <7 days (n = 52), group 2: 7-14 days (n = 13) and group 3 (n = 18): >14 days]. The creatinine clearance (CrCl) at 30 days (42.5, 33.8, 20.0 cc/min; P < 0.001) and 1 year (56.7, 49.2, 37.3 cc/min, P = 0.031) were significantly different between the three groups. Multivariate regression analysis identified length of TND posttransplant (β = -0.5, P < 0.001) and donation after cardiac death (DCD) donor (β = 19.5, P < 0.001) as the most significant predictors of CrCl at 1 year in these patients with DGF. DCD kidneys with DGF had a higher CrCl at 1 year and fewer readmissions in the first year compared with non-DCD kidneys with DGF.

DISCUSSION

Our study suggests that increased TND is associated with worse CrCl at 1 year. The data also support the hypothesis of a different mechanism for DGF in DCD and non-DCD kidneys.

Anti-inflammatory profile of paricalcitol in hemodialysis patients: a prospective, open-label, pilot study

Inflammation is a strong predictor of increased morbidity and mortality in hemodialysis (HD) patients. Paricalcitol, a selective vitamin D receptor activator used for prevention and treatment of secondary hyperparathyroidism, has shown anti-inflammatory properties in experimental studies, although clinical data are scarce. In an open-label, prospective, single center, pilot study, 25 stable HD patients, previously receiving calcitriol, completed 12 weeks of therapy with oral paricalcitol. Serum and peripheral blood mononuclear cell (PBMC) expression profiles of inflammatory cytokines were analyzed. Serum interleukin (IL)-1, IL-10, and IL-18 did not change, unlike high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), and IL-6, which experienced a significant mean percent decrease of 14.3%, 4.7%, and 5%, respectively. There was a significant reduction in the TNF-α/IL-10 and the IL-6/IL-10 ratios (P < .05). Serum intact parathyroid hormone concentration experienced a mild but significant reduction. In addition, expression levels of TNF-α and IL-6 decreased by 19.1% (P < .01) and 17.5% (P < .001), respectively, whereas expression of IL-10 increased by 17.7% (P < .01) after treatment. In conclusion, paricalcitol administration to HD patients is associated with a beneficial effect on the inflammatory cytokine serum and gene expression profile of PBMC. This effect may contribute to the survival benefits of paricalcitol observed in clinical studies.

Fibroblast growth factor-23 and interleukin-6 are risk factors for left ventricular hypertrophy in peritoneal dialysis patients

BACKGROUND

Left ventricular hypertrophy (LVH) is a major risk factor for cardiovascular death in dialysis patients. Fibroblast growth factor-23 (FGF-23) and interleukin-6 (IL-6) were thought to be related to cardiovascular diseases (CVDs) in dialysis.

METHODS

To determine the relationship between FGF-23, IL-6 and LVH in continuous ambulatory peritoneal dialysis (CAPD) patients, serum FGF-23 and IL-6 levels as well as standard laboratory parameters were assessed in 62 CAPD patients and 30 healthy controls. LVH was determined by echocardiography in dialysis patients.

RESULTS

Serum FGF-23 and IL-6 levels were significantly higher in CAPD patients than in healthy controls, whereas both were higher in patients with LVH than in patients without LVH. FGF-23 was found to be positively associated with left ventricle mass index (LVMI) and serum phosphate. IL-6 level was positively associated with LVMI and negatively correlated with serum albumin and hemoglobin. Serum FGF-23 level was positively correlated with IL-6 level.

CONCLUSION

FGF-23 and IL-6 are independent risk factors for LVH in CAPD patients and both collaborated in causing LVH in CAPD.

Lanthanum Carbonate Modulates Inflammatory Profile in Hemodialysis Patients: Relationship with Fibroblast Growth Factor-23

Elevated fibroblast growth factor 23 (FGF-23) is independently associated with increased inflammatory markers in chronic kidney disease. Lanthanum carbonate (LaCa) reduces FGF-23. We studied the effects of LaCa on inflammatory profile of hemodialysis patients, and the relationship with changes in FGF-23. This prospective study was performed under habitual clinical practice conditions. Twenty-six hemodialysis patients with serum phosphate > 5 mg/dl receiving calcium-based phosphate binders were switched to LaCa. Ten patients with phosphate ≤ 5 mg/dl under calcium-based phosphate binders were enrolled as a control group for comparison. Serum calcium, phosphorus, calcium-phosphate product (CaxP), intact parathyroid hormone and the inflammatory profile [including serum high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-10, as well as mRNA expression levels of TNF-α and IL-6 in peripheral blood mononuclear cells] were analyzed. Serum FGF-23 significantly decreased in patients switched to LaCa (P< 0.01), with a concomitant reduction in serum hsCRP (-10.9%, P < 0.01), TNF-α (-6.7%, P < 0.05) and IL-6 (-8.1%, P < 0.01). mRNA expression levels of TNF-α and IL-6 in PBMC also decreased by 7.8% (P< 0.05) and 10.3% (P< 0.01), respectively. Multivariate regression analysis demonstrated that variations in FGF-23 were the only independent determinant of the changes in serum and mRNA expression levels of inflammatory parameters. In conclusion, LaCa posses anti-inflammatory actions, which are significant and independently associated with the reduction of FGF-23. FGF-23 may regulate inflammatory cytokine gene expression at the transcriptional level. Whether these effects have influence on clinical outcomes warrants consideration.

Association of response to hepatitis B vaccination and survival in dialysis patients

Background

The status of immunocompromised patients is well recognized in end stage renal disease (ESRD). As described recently, this acquired immune dysfunction in the uremic milieu may be one of the main pathogenic factors for mortality in ESRD. The aim of this study was to determine the relationship between the immune response following a hepatitis B vaccination (HBV vaccination) and the survival of maintenance dialysis patients.

Methods

A total of 156 patients (103 on hemodialysis and 53 on continuous ambulatory peritoneal dialysis) were recruited. After receiving a full dose of the HBV vaccination, all patients were followed up for to 5 years to evaluate the association of patient survival, cause of mortality, and immune response.

Results

The response rate to the hepatitis B vaccination was 70.5%. There was no significant association between the immune response and the 5-year survival rate (p =0.600) or between the post-vaccination anti-HBs titers and the 5-year survival rate (p = 0.201). The logistic prediction model with the coefficient as non-response following HBV vaccination, diabetes mellitus, old age, and low albumin level could significantly predict infection-cause mortality (sensitivity = 0.842, specificity = 0.937).

Conclusion

There was no significant association between the immune response to HBV vaccination and the 5-year survival rate. However, non-response following HBV vaccination might be associated with infection-cause mortality in dialysis patients.

Plasma protein characteristics of long-term hemodialysis survivors

Hemodialysis (HD) patients are under recurrent circulatory stress, and hemodialysis has a high mortality rate. The characteristics of plasma proteomes in patients surviving long-term HD remain obscure, as well as the potential biomarkers in predicting prognoses. This study reports the proteome analyses of patient plasma from non-diabetic long-term HD (LHD, dialysis vintage 14.9±4.1 years, n = 6) and the age/sex/uremic etiology-comparable short-term HD (SHD, dialysis vintage 5.3±2.9 years, n = 6) using 2-DE and mass spectrometry. In addition, a 4-year longitudinal follow-up of 60 non-diabetic HD patients was subsequently conducted to analyze the baseline plasma proteins by ELISA in predicting prognosis. Compared to the SHD, the LHD survivors had increased plasma vitamin D binding proteins (DBP) and decreased clusterin, apolipoprotein A-IV, haptoglobin, hemopexin, complement factors B and H, and altered isoforms of α1-antitrypsin and fibrinogen gamma. During the 45.7±15 months for follow-up of the 60 HD patient cases, 16 patients died. Kaplan-Meier analysis demonstrated that HD patients with the lowest tertile of the baseline plasma DBP level have a significantly higher mortality rate. Multivariate Cox regression analysis further indicated that DBP is an independent predictor of mortality. In summary, the altered plasma proteins in LHD implicated accelerated atherosclerosis, defective antioxidative activity, increased inflammation/infection, and organ dysfunction. Furthermore, lower baseline plasma DBP in HD patients is related to mortality. The results suggest that the proteomic approach could help discover the potential biomarker in HD prognoses.

Supplementation of Emblica Officinalis (Amla) Extract Reduces Oxidative Stress in Uremic Patients

Emblica Officinalis (also known as Amla or Indian Gooseberry), a natural, traditional and functional food in Asia, has physiological benefits such as hepato-, cyto- and radio- protection, as well as hypolipidemic effects. In addition, Amla often functions as a potent antioxidant due to the high level of ascorbic acid (ranging from 1,100 to 1,700 mg/100 g of fruit) in its fruit. The aim of this study was to determine whether supplementation with Amla extract could reduce oxidative stress in patients with uremia. The findings show that supplementation with Amla extract for 4 months reduced the plasma oxidative marker, 8-iso-prostaglandin, (M0 vs. M4 = 1415 ± 1234 pg/ml vs. 750 ± 496 pg/ml, p < 0.05) and increased plasma total antioxidant status (TAS) (M0 vs. M4 = 2.32 ± 0.14 mM vs. 2.55 ± 0.24 mM, p < 0.05) in uremic patients. On the other hand, there were no significant differences observed in liver function (GOP and GPT), renal function (creatinine, blood urea nitrogen and uric acid), diabetic index (plasma glucose and adiponectin) and atherogenic index (LDL/HDL ratio, total cholesterol and homocysteine) in patients treated with Amla for 4 months. Our data suggest that Amla supplementation may increase plasma antioxidant power and decrease oxidative stress in uremic patients. However, Amla extract did not influence hepatic or renal function, or diabetic and atherogenic indices in uremic patients.

Apoptotic cell-free DNA promotes inflammation in haemodialysis patients

BACKGROUND

A proinflammatory environment characterized by the continuous activation of the innate immune system is thought to contribute to the markedly elevated mortality in haemodialysis (HD) patients with end-stage renal disease (ESRD). The presence of circulating cell-free DNA (cfDNA) has been demonstrated as biomarker in many pathologies.

METHODS

We evaluated the occurrence of cfDNA in HD patients and its functional relevance for innate immunity and inflammation.

RESULTS

Here, we found that cfDNA was enhanced in the plasma of ESRD patients after HD compared to healthy controls. Functionally, cfDNA selectively stimulated the production of the proinflammatory cytokine interleukin (IL)-6 by human monocytes, whereas tumour necrosis factor-α or IL-10 was not induced. Conversely, plasma from HD patients, but not from healthy controls or DNase I-treated HD plasma, induced IL-6 production from monocytes.

CONCLUSION

We provide the first evidence that cfDNA has selective immunostimulatory effects on human monocytes. This process may contribute to the proinflammatory milieu observed in HD patients.

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.

Effect of phosphate binders on serum inflammatory profile, soluble CD14, and endotoxin levels in hemodialysis patients

BACKGROUND AND OBJECTIVES

Hyperphosphatemia and subclinical endotoxemia are important sources of inflammation in HD. Proinflammatory cytokines are strong correlates of soluble CD14 (sCD14) concentrations, an independent predictor of mortality in this population. We evaluated the effects of calcium acetate and sevelamer hydrochloride on serum inflammatory profile, endotoxin concentrations, and sCD14 levels in HD patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Prospective, randomized, open-label, parallel design trial. Fifty-nine stable HD patients, 30 receiving sevelamer, and 29 receiving calcium acetate were evaluated. Serum levels of inflammatory parameters (high-sensitivity C-reactive protein [hs-CRP], TNF-α, interleukin (IL)-1, -6, -10, and -18), as well as endotoxin and sCD14 concentrations, were measured at baseline and after 3 months of therapy.

RESULTS

Serum IL-6 increased in patients receiving calcium acetate, whereas hs-CRP and IL-6 significantly decreased in subjects treated with sevelamer, with IL-10 experiencing a trend to increase (P = 0.052). Serum endotoxin and sCD14 levels did not change after treatment with calcium acetate. However, these parameters decreased by 22.6% and 15.2%, respectively (P < 0.01), in patients receiving sevelamer. Multiple regression analysis showed that variation in serum endotoxin concentrations was the strongest factor associated with IL-6 change, whereas the only variables independently associated with changes in sCD14 levels were the variations in serum IL-6 and endotoxin concentrations.

CONCLUSIONS

Administration of the noncalcium phosphate binder sevelamer to maintenance HD patients is associated with a significant decrease in hs-CRP, IL-6, serum endotoxin levels and sCD14 concentrations.

Association of low glomerular filtration rate with the incidence of stroke in patients following complete coronary revascularization

BACKGROUND

Low glomerular filtration rate (GFR) is associated with a worse outcome after coronary revascularization. Recently, a new specific equation to calculate the estimated GFR (eGFR) in Japanese populations has been reported, and it might be more accurate than the previously used equations. However, the relationship between a low GFR defined using the new equation for the Japanese population and the incidence of stroke following complete coronary revascularization is not yet known.

METHODS AND RESULTS

Consecutive patients who underwent complete coronary revascularization (percutaneous coronary intervention and bypass surgery) between 1984 and 1992 were enrolled. Patients on dialysis were excluded. Enrolled patients were divided into 2 groups: the preserved GFR group and the low GFR group. Low GFR was defined as eGFR<60 ml·min⁻¹·1.73 m⁻². The incidence of fatal and non-fatal stroke was compared between the groups. Among the 1,809 patients that were enrolled, 321 were placed in the low GFR group. During follow up (mean, 11.4 [2.9] years), there were 127 (7.0%) stroke events. Multivariable analysis using a Cox proportional hazards regression model revealed that the incidence of stroke was significantly higher in the low GFR group than in the preserved GFR group (hazard ratio, 1.66; 95% confidence interval, 1.10-2.48; P = 0.008).

CONCLUSIONS

Low GFR, defined as eGFR <60 ml·min⁻¹·1.73 m⁻², using a new specific equation for the Japanese population was associated with an increased risk of fatal and non-fatal stroke over a 10-year period after complete coronary revascularization.

Bio-incompatibility and Th2 polarization during regular dialysis treatment

Long-term hemodialysis treatment results in chronic monocyte activation with cytokine release. It generates Treg induction with potential immune dysfunction and associated clinical complications. Recent immunological data and preliminary clinical evidence suggest that synthetic polymers and vitamin E coated membranes are associated with a significant improvement in hemodialysis tolerance when compared to cellulose membranes. The aim of this review is to update cytokine release, T-cell polarization, and its clinical impact in patients under extracorporeal hemodialysis comparing traditional cellulose to synthetic/vitamin E coated membranes.

Proteomic profiling of blood-dialyzer interactome reveals involvement of lectin complement pathway in hemodialysis-induced inflammatory response

PURPOSE

dialysis-induced inflammatory response including leukocyte and complement activation is considered a significant cofactor of chronic morbidity in long-term hemodialysis (HD) patients. The aim of this study was to provide better insight into its molecular background.

EXPERIMENTAL DESIGN

in 16 patients, basic biocompatibility markers, i.e. leukocyte counts and C5a levels, were monitored during HD on a polysulfone membrane. Proteins adsorbed to dialyzers were eluted and separated by 2-DE. Selected proteins were identified by MS; ficolin-2 plasma levels were assessed. Data are given as medians (quartile ranges).

RESULTS

in total, 7.2 (34.7) mg proteins were retrieved from dialyzer eluates and were resolved into 217 protein spots. The proteins most enriched in eluates (and hence selectively adsorbed) were those involved in complement activation (C3c, ficolin-2, mannan-binding lectin serine proteases, properdin) and cell adhesion (actin, caldesmon, tropomyosin, vitronectin, vinculin). A significant decrease of plasma ficolin-2 (41% [4.7], p<0.001) was evidenced during one HD session, associated with leukopenia (r=0.73, p=0.001) and C5a production (r=-0.62, p=0.01) at 15 min.

CONCLUSIONS AND CLINICAL RELEVANCE

ficolin-2 adsorption to polysulfone dialyzer initiates the lectin pathway of complement activation, mediates dialysis-induced leukopenia, and results in a significant depletion of ficolin-2, an essential component of innate immunity.

Proinflammatory cytokines, hepatocyte growth factor and adipokines in peritoneal dialysis patients

Chronic inflammation is a well-recognized complication in dialysis patients and a potential role of the adipose tissue as an important tissue of origin contributing to inflammation has been proposed. Stable peritoneal dialysis (PD) patients were enrolled to investigate the relationship between serum levels of proinflammatory cytokines and adipokines. Our results revealed that there was a strong association between high sensitivity C-reactive protein and interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-alpha) but not with IL-10 and IL-18. IL-6 correlated with TNF-alpha, IL-10, and IL-18. No association was found between IL-10 and IL-18. Adiponectin was positively correlated with all proinflammatory cytokines, except IL-10. No significant association was found between resistin and proinflammatory cytokines. Hepatocyte growth factor (HGF) was directly related to proinflammatory cytokines but not with adipokines. The presence of residual kidney function (RKF) affected IL-6, TNF-alpha, and HGF levels. The peritoneal transport property did not influence inflammatory cytokine and adipokine levels. In conclusion, there was a close relationship between proinflammatory cytokines and adipokines. HGF correlated with proinflammatory cytokines but not with adipokines. The PD-related factors such as RKF, peritoneal property and dialysis glucose load affected levels of proinflammatory cytokines. Body mass index was an important determinant of leptin and adiponectin in PD patients.

Inflammation and oxidative stress in end-stage renal disease patients treated with hemodialysis or peritoneal dialysis

PURPOSE

The impact of different dialysis modalities on oxidative stress and inflammation and the factors implicated in this interrelationship have not been adequately studied. This study was designed to comparatively evaluate the effect of hemodialysis (HD) and peritoneal dialysis (PD) on oxidative stress and inflammatory biomarkers and to search for associated factors.

METHODS

We studied 20 HD, 11 PD patients and 11 healthy controls. Calculations were based on total antioxidant capacity (TAC) and superoxide dismutase (SOD), by spectrophotometry, as oxidative stress biomarkers; and high sensitivity CRP (hs-CRP), Interleukin-6 (IL-6) and Tumor Necrosis Factor-alpha (TNF-alpha), by ELISA, as inflammation biomarkers.

RESULTS

HD and PD patients showed significantly increased levels of TA C, SOD and hs-CRP compared to healthy controls. No significant difference was observed in TNF-alpha and IL-6. Compared to HD patients, PD patients showed TNF-alpha levels that were increased, although non-significantly, and significantly higher homocysteine (Hcy). No differences were observed for IL-6, hs-CRP, TA C and SOD. In HD patients, significant positive correlations were found between intact parathyroid hormone (iPTH) and TNF-alpha, and between uric acid (UA) and TAC. Beta2-microglobulin (Beta2M) was negatively correlated with TAC, total cholesterol (TC) positively with TNF-alpha and negatively with SOD, and triglycerides (TG) correlated positively with TNF-alpha. In PD patients, TG correlated positively with TNF-alpha, HDL-cholesterol negatively with TNF-alpha, LDL-cholesterol negatively with SOD, and Beta2M negatively with SOD.

CONCLUSIONS

HD and PD patients show similar degrees of inflammation and oxidative stress activation. Factors such as UA, iPTH, Beta2M and lipid profile correlate to oxidative stress and inflammatory biomarkers in both HD and PD patients.

Sevelamer and the bone-vascular axis in chronic kidney disease: bone turnover, inflammation, and calcification regulation

Hyperphosphatemia is a central characteristic feature of chronic kidney disease-mineral and bone disorder (CKD-MBD). Phosphorus excess is an independent cardiovascular risk factor for morbidity and mortality in patients with advanced CKD. Over the past 40 years, hyperphosphatemia has been a central therapeutic issue in advanced CKD. Mainstays of hyperphosphatemia treatment are reduction of dietary phosphorus, use of phosphate binders, and optimized phosphorus removal via dialysis. Currently, several phosphate binders are approved for use (aluminum, calcium, lanthanum, sevelamer); all share a common functionality in that they bind phosphorus and reduce the amount absorbed in the gastrointestinal lumen. Over the last decade, nephrologists have debated the relative tolerability and efficacy of these agents, especially the potential for vascular calcification and cardiovascular risk reduction. Recent research has focused on the question of whether a metal-free, calcium-free, and non-absorbed binder, such as sevelamer, offers advantages over other binder types. Most notable may be the potential benefit of reducing calcium load. In addition, sevelamer has several additional pleiotropic effects that may extend its basic indication, some of which may help attenuate vascular calcification. These include effects on bone turnover and the link between abnormal vascular processes and bone metabolism (the so-called 'bone-vascular axis'), as well as lipid metabolism, and systemic inflammatory mediators such as fetuin-A. We review the evidence for these pleiotropic effects, and suggest these may help in some way to improve the substantial disease burden in the CKD-MBD population.

Metabolic syndrome predicts mortality in non-diabetic patients on continuous ambulatory peritoneal dialysis

BACKGROUND

Metabolic syndrome is associated with higher morbidity and mortality in the general population, but the corresponding effects in patients on dialysis have not been clearly defined. In this study, we prospectively investigated the effect of metabolic syndrome and its individual components on outcome in non-diabetic peritoneal dialysis (PD) patients. Method. The study subjects included 106 stable non-diabetic PD patients who had been on PD for >3 months. We measured baseline characteristics, blood pressure, fasting blood glucose, lipid profiles and high-sensitivity CRP (hsCRP), and defined metabolic syndrome using the modified National Cholesterol Education Program (Adult Treatment Panel III) criteria. Mortality, technical failure and hospitalization were evaluated during the follow-up period.

RESULTS

Metabolic syndrome was present in 50 patients (47.2%), and these showed higher baseline hsCRP levels (0.67; 95% CI: 0.50-0.94 versus 1.78 mg/dl; 95% CI: 1.21-2.57; P < 0.001). Patients with metabolic syndrome experienced significantly lower 5-year survival rates than patients without (90% versus 67%, P = 0.02), although these groups did not differ in peritonitis rates, technical failure or hospitalization. A Cox proportional hazards analysis identified the following as predictors of mortality: metabolic syndrome (RR: 3.39; 95% CI: 1.16-9.94; P = 0.02), baseline albumin (RR: 0.06; 95% CI: 0.01-0.30; P = 0.001) and baseline hsCRP levels (RR: 1.14; 95% CI: 1.07-1.22; P < 0.001).

CONCLUSION

Metabolic syndrome is prevalent and is a risk factor influencing long-term survival in non-diabetic PD patients.

Antioxidant enzymes show adaptation to oxidative stress in athletes and increased stress in hemodialysis patients

The aim of the study is to compare oxidative stress in hemodialysis patients in controls and in rowers. The patients are a model of decreased antioxidant capacity, and the athletes (rowers) are a model of the highest antioxidant capacity due to their chronic adaptation to demanding training. Thirty-five subjects participated in the study, 9 patients with end-stage renal disease treated by hemodialysis, 12 healthy young subjects from the normal population, and 14 rowers. The antioxidant enzymes catalase, superoxide dismutase, and glutathione peroxidase, as well as non-transferrin-bound iron as a promoter of free radical damage, were determined. Blood analysis was taken in dialysis patients in the morning, before the dialysis procedure. There was significantly higher activity of catalase in dialysis patients (catalase 4.26 +/- 0.35 mkat/g Hb) compared to the controls (catalase 2.73 +/- 0.38 mkat/g Hb) and rowers (catalase 1.71 +/- 0.30 mkat/g Hb). Superoxide dismutase activity was significantly lower (10.42 +/- 1.46 microkat/g Hb) than in the controls (11.94 +/- 1.18 microkat/g Hb) and rowers (14.09 +/- 0.92 microkat/g Hb). There was no significant differences between glutathione peroxidase activities in the three groups. Superoxide dismutase and Se were higher in rowers than in dialysis patients (P < 0.05). The concentrations of both non-transferrin-bound iron and ferritin were significantly higher in dialysis patients. Hemodialysis patients might have increased oxidative stress, which is characterized by significantly higher erythrocyte enzyme activity of catalase and lower activity of superoxide dismutase. Top rowers had increased superoxide dismutase and glutathione peroxidase, perhaps because of adaptation during training, which was not the case in dialysis patients and controls.

Microcirculatory changes and skeletal muscle oxygenation measured at rest by non-infrared spectroscopy in patients with and without diabetes undergoing haemodialysis

Introduction

Haemodialysis has direct and indirect effects on skin and muscle microcirculatory regulation that are severe enough to worsen tolerance to physical exercise and muscle asthenia in patients undergoing dialysis, thus compromising patients' quality of life and increasing the risk of mortality. In diabetes these circumstances are further complicated, leading to an approximately sixfold increase in the incidence of critical limb ischaemia and amputation. Our aim in this study was to investigate in vivo whether haemodialysis induces major changes in skeletal muscle oxygenation and blood flow, microvascular compliance and tissue metabolic rate in patients with and without diabetes.

Methods

The study included 20 consecutive patients with and without diabetes undergoing haemodialysis at Sant Andrea University Hospital, Rome from March to April 2007. Near-infrared spectroscopy (NIRS) quantitative measurements of tissue haemoglobin concentrations in oxygenated [HbO₂] and deoxygenated forms [HHb] were obtained in the calf once hourly for 4 hours during dialysis. Consecutive venous occlusions allowed one to obtain muscular blood flow (mBF), microvascular compliance and muscle oxygen consumption (mVO₂). The tissue oxygen saturation (StO₂) and content (CtO₂) as well as the microvascular bed volume were derived from the haemoglobin concentration. Nonparametric tests were used to compare data within each group and among the groups and with a group of 22 matched healthy controls.

Results

The total haemoglobin concentration and [HHb] increased significantly during dialysis in patients without and with diabetes. Only in patients with diabetes, dialysis involved a [HbO₂], CtO₂ and increase but left mVO₂ unchanged. Multiple regression StO₂ analysis disclosed a significant direct correlation of StO₂ with HbO₂ and an inverse correlation with mVO₂. Dialysis increased mBF only in diabetic patients. Microvascular compliance decreased rapidly and significantly during the first hour of dialysis in both groups.

Conclusions

Our NIRS findings suggest that haemodialysis in subjects at rest brings about major changes in skeletal muscle oxygenation, blood flow, microvascular compliance and tissue metabolic rate. These changes differ in patients with and without diabetes. In all patients haemodialysis induces changes in tissue haemoglobin concentrations and microvascular compliance, whereas in patients with diabetes it alters tissue blood flow, tissue oxygenation (CtO₂, [HbO₂]) and the metabolic rate (mVO₂). In these patients the mVO₂ is correlated to the blood supply. The effects of haemodialysis on cell damage remain to be clarified. The absence of StO₂ changes is probably linked to an opposite [HbO₂] and mVO₂ pattern.

Upregulation of monocyte/macrophage HGFIN (Gpnmb/Osteoactivin) expression in end-stage renal disease

BACKGROUND AND OBJECTIVES

Hematopoietic growth factor-inducible neurokinin 1 (HGFIN), also known as Gpnmb and osteoactivin, is a transmembrane glycoprotein that is expressed in numerous cells, including osteoclasts, macrophages, and dendritic cells. It serves as an osteoblast differentiation factor, participates in bone mineralization, and functions as a negative regulator of inflammation in macrophages. Although measurable at low levels in monocytes, monocyte-to-macrophage transformation causes substantial increase in HGFIN expression. HGFIN is involved in systemic inflammation, bone demineralization, and soft tissue vascular calcification.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We explored HGFIN expression in monocytes and monocyte-derived macrophages in 21 stable hemodialysis patients and 22 control subjects.

RESULTS

Dialysis patients exhibited marked upregulation of colony-stimulating factor and IL-6 and significant downregulation of IL-10 in intact monocytes and transformed macrophages. HGFIN expression in intact monocytes was negligible in control subjects but conspicuously elevated (8.6-fold) in dialysis patients. As expected, in vitro monocyte-to-macrophage transformation resulted in marked upregulation of HGFIN in cells obtained from both groups but much more so in dialysis patients (17.5-fold higher). Upregulation of HGFIN and inflammatory cytokines in the uremic monocyte-derived macrophages occurred when grown in the presence of either normal or uremic serum, suggesting the enduring effect of the in vivo uremic milieu on monocyte/macrophage phenotype and function.

CONCLUSIONS

Uremic macrophages exhibit increased HGFIN gene and protein expression and heightened expression of proinflammatory and a suppressed expression of anti-inflammatory cytokines. Further studies are needed to determine the role of heightened monocyte/macrophage HGFIN expression in the pathogenesis of ESRD-induced inflammation and vascular and soft tissue calcification.

Association of white blood cell count with metabolic syndrome in patients undergoing peritoneal dialysis

Metabolic syndrome is associated with an increased risk of diabetes and cardiovascular disease. Although some data suggest that the prevalence of metabolic syndrome is higher in patients undergoing peritoneal dialysis (PD), the factors related to this increased risk are not well elucidated. We therefore examined whether peripheral white blood cell (WBC) count is correlated with the risk of metabolic syndrome in nondiabetic PD patients. We enrolled 104 nondiabetic PD patients without current infections or chronic inflammatory diseases. Complete blood cell count, anthropometry, blood pressure, fasting glucose, insulin, and lipid profiles were measured. Metabolic syndrome was defined in accordance with the National Cholesterol Education Program (Adult Treatment Panel III) criteria. Metabolic syndrome was present in 49 patients (47.1%). Patients with metabolic syndrome had a higher WBC count and high-sensitivity C-reactive protein level. As the number of metabolic syndrome components increased, WBC count increased significantly. White blood cell count was significantly positively correlated with body mass index, insulin, homeostasis model assessment of insulin resistance, and triglyceride and negatively correlated with high-density lipoprotein cholesterol. The risk of metabolic syndrome increased significantly with a higher WBC count, resulting in an adjusted odds ratio of 1.65 (per 10(3)/muL increase, P = .002). These findings demonstrate that metabolic syndrome is prevalent among nondiabetic PD patients and that WBC count is strongly associated with metabolic syndrome and its components.

Specific adsorption of some complement activation proteins to polysulfone dialysis membranes during hemodialysis

Dialyser bioincompatibility is an important factor contributing to complications of hemodialysis with well known systemic consequences. Here we studied the local processes that occur on dialysis membranes by eluting proteins adsorbed to the polysulfone dialyser membranes of 5 patients after 3 consecutive routine maintenance hemodialysis sessions. At the end of each procedure, a plasma sample was also collected. These eluates and their accompanying plasma samples were separated by 2-dimensional gel electrophoresis; all proteins that were present in all patients were analyzed by tandem mass spectrometry; and a ratio of the relative spot intensity of the eluate to plasma was calculated. Of 153 proteins detected, 84 were found in all patients, 57 of which were successfully identified by mass spectrometry as 38 components of 23 unique proteins. In 10 spots the relative eluate intensity differed significantly from that in the plasma, implying preferential adsorption. These proteins included ficolin-2, clusterin, complement C3c fragment, and apolipoprotein A1. Our finding of a selective binding of ficolin-2 to polysulfone membranes suggests a possible role of the lectin complement pathway in blood-dialyser interactions.

Chemiluminescent analysis of plasma antioxidant capacity in uremic patients undergoing hemodialysis

OBJECTIVE

Hemodialysis is a common therapeutic strategy for patients with end stage renal failure. During the hemodialytic process, the neutrophils are activated (neutrophil burst) due to the hemoincompatibility induced by hemodialysis. As a result, the activated neutrophils release reactive oxygen species (ROS), such as hydrogen peroxide, singlet oxygen, and hypochlorite, into the bloodstream and cause oxidative damage.

METHODS

This study investigated the antioxidant alteration of plasma in uremic patients undergoing hemodialysis by chemiluminescent analysis. The antioxidant capacities of plasma in scavenging hydrogen peroxide, singlet oxygen, and hypochlorite were investigated in this experiment. In addition, investigation of the ferric-reducing ability of plasma (FRAP) would be covered in this study as well.

RESULTS

This study found that after hemodialysis, the antioxidant capacities of plasma in scavenging hydrogen peroxide, singlet oxygen, and hypochlorite decreases 7.9%, 18.8%, and 18.9%, respectively. Moreover, the FRAP is reduced by 56%. We speculate that the loss of dialyzable solutes (such as uremic solutes and antioxidants with small molecular weight) in plasma resulted in its decrease in antioxidant capacity.

CONCLUSION

We therefore suggest that the supplement of antioxidants with small molecular weight is capable of regaining antioxidant defense in plasma and preventing oxidative damage induced by hemodialysis.