Associations between circulating inflammatory markers and residual renal function in CRF patients

The importance of residual renal function in peritoneal dialysis

BACKGROUND

Peritoneal dialysis (PD) patients with preserved residual diuresis have a lower risk of death and complications. Here we analyzed associations between residual diuresis and presence of fluid overload and biomarkers of cardiac strain and nutrition in PD patients.

METHODS

Among 44 PD patients placed into three subgroups, depending on volume of residual diuresis (group A ≤ 500; group B 600-1900; and group C ≥ 2000 mL/day), we examined: overhydration (OH) assessed by bioimpedance analysis (BIA; yielding OH index OHBIA) and by clinical criteria (edema and hypertension); nutritional status (by subjective global assessment, SGA); metabolic status (electrolytes, serum lipid profile, CRP, and albumin); biomarkers of fluid overload and cardiac strain (N-terminal probrain natriuretic peptide, NT-proBNP, and troponin T, TnT); and, echocardiography and chest X-ray.

RESULTS

With increasing residual diuresis in group A, B and C, fewer patients had signs of overhydration defined as OHBIA > 1.1 L (75.0, 42.9 and 33.3 %) or peripheral edema (25.0, 21.4 and 0 %) and NT-proBNP (15199 ± 16150 vs. 5930 ± 9256 vs. 2600 ± 3907 pg/mL; p < 0.05) and TnT (0.15 ± 0.17 vs. 0.07 ± 0.09 vs. 0.04 ± 0.03 ng/mL; p < 0.05) were significantly lower. Significant differences were found also in ejection fraction, SGA, and total cholesterol, albumin and hemoglobin levels whereas blood pressures and serum CRP did not differ significantly.

CONCLUSION

Signs of OH and cardiac strain are common in PD patients, even in those with diuresis of 1000-2000 mL/day and with no clinical signs or symptoms, suggesting that even moderate decrease in residual renal function in PD patients associate with OH and other complications.

Association of E-selectin with hematological, hormonal levels and plasma proteins in children with end stage renal disease

Background:

Hypercoagulable state is a common serious problem in patients with end-stage renal disease (ESRD). ESRD patients are in a condition of chronic inflammation. An increased level of E-selectin, “a key adhesion molecule that regulates leukocyte bindings to endothelium at damaged sites,” accompanies the higher risk of inflammation in ESRD patients. We aimed to investigate the possible correlation among E-selectin as an adhesion molecule, coagulation factors, and inflammatory factors in children with ESRD.

Materials and Methods:

Thirty-five child patients with ESRD who had been on regular dialysis treatment were registered in our study. Nighteen sex- and age-matched healthy volunteers were used as the control group. Laboratory tests were requested for the evaluation of hematological and biochemical parameters, and parathyroid hormone (PTH), and for coagulation state; fibrinogen, protein C, and protein S were measured. The enzyme-linked immunosorbent assay (ELISA) (Biomerica, CA, and IDS, UK). for serum E-selectin assay was provided by R and D Systems (Abingdon, UK).

Results:

Hemoglubolin (Hb), blood urea nitrogen (BUN), creatinine, calcium, PTH, triglyceride (TG) concentrations in serum as well as E-selectin showed significant difference between the two study groups, as indeed was expected. Serum E-selectin was significantly higher (P value = 0.033) in dialysis patients than in healthy subjects. E-selectin was positively correlated only with phosphorus in ESRD children (r = 0.398, P = 0.018). No association was found for other parameters.

Conclusion:

Although in our study circulating E-selectin concentration “as an inflammatory maker” is independently positively associated with limited blood markers, for better evaluation, well-designed cohort studies should be examined in ESRD children.

[Chronic kidney failure and carotid atherosclerosis in diabetic patient]

INTRODUCTION

Chronic kidney failure is an independent risk factor of cardiovascular disease. Its association with carotid atherosclerosis remains controversial. The purpose of our study was to assess the factors associated with carotid atherosclerosis specially the components of chronic kidney disease.

METHODS

In a cross-sectional study, we enrolled type 1 or type 2 diabetic patients from the endocrinology an diabetology department of the military hospital of Rabat assigned in two groups according to the presence or absence of carotid atherosclerosis. Kidney function was assessed based on albuminuria and the estimated glomerular filtration rate calculated using the "modification of diet in renal disease" equation. A multiple logistic regression analysis was performed to identify independent factors associated with carotid atherosclerosis.

RESULTS

One hundred and six diabetic patients were enrolled including 96 type 2 diabetic patients. Age (P<0.001), diabetes duration (P=0.04), hypertension (P=0.002), peripheral arterial disease (P<0.001) and chronic kidney failure (P=0.001) were significantly associated with carotid atherosclerosis. After adjusting for age, hypertension, diabetes duration and peripheral arterial disease, chronic kidney failure was an independent factor associated with carotid atherosclerosis (OR: 5.46; 95%IC: 1.29-23.01; P=0.021).

CONCLUSION

Our data suggest that chronic kidney failure is associated with carotid atherosclerosis in diabetic patients independently of the common cardiovascular risk factors.

Changes in the inflammatory markers with advancing stages of diabetic nephropathy and the role of pentraxin-3

BACKGROUND

Immunological and inflammatory mechanisms have been shown to have role in both the development and progression of diabetic nephropathy (DNP). There is need for more specific markers for inflammation as the ones commonly used are influenced by many factors. Pentraxin-3 (PTX-3) seems to be a potential candidate. We aimed in our study to evaluate the changes of PTX-3 levels in different stages of DNP and its relationship with other inflammatory markers.

METHODS

This is a cross sectional study in which patients with DNP at different stages were involved. Patient were divided into three groups according to estimated glomerular filtration rate (eGFR), microalbuminuria and proteinuria levels: Group-1: eGFR >60 mL/min and microalbuminuria, Group-2: eGFR >60 mL/min and macroalbuminuria, Group-3: eGFR <60 mL/min and macroalbuminuria. Besides the routine biochemical parameters, levels of PTX-3, high sensitivity C-reactive protein (hsCRP), interleukin (IL)-1 and tumor necrosis factor (TNF)-α was measured. Groups were compared with each other regarding the study parameters and correlation of PTX-3 with other markers was evaluated.

RESULTS

The mean PTX-3 level in Group-2 (0.94 ± 0.26 ng/mL) and -3 (1.35 ± 1.55 ng/mL) were higher than in Group-1 (0.81 ± 0.25 ng/mL) (p = 0.009 and p = 0.012). There was a significant correlation of PTX-3 with proteinuria (r = 0.266, p = 0.016), microalbuminuria (r = 0.304, p = 0.014) and hypoalbuminemia (r = 0.197, p = 0.043). PTX-3 was not correlated with other markers of inflammation (IL-1, TNF-α and hsCRP) and diabetic metabolic parameters (hbA1c, C-peptide, insulin and HOMA-IR). PTX-3, IL-1 and TNF-α levels increased with the advancing stage of DNP while hsCRP level did not change.

CONCLUSION

PTX-3 that increases similar to other markers of inflammation (IL-1, TNF-α) is a better inflammatory marker than hsCRP. Furthermore, there is a relationship between PTX-3 and proteinuria independent from eGFR.

Resveratrol ameliorates renal injury in spontaneously hypertensive rats by inhibiting renal micro-inflammation

Micro-inflammation plays an important role in the pathogenesis of spontaneously hypertensive rat (SHR). In the present study, we investigated the therapeutic potential of resveratrol (RSV), a polyphenol with anti-fibrosis activity in hypertensive renal damage model. In SHR renal damage model, RSV treatment blunted the increase in urine albumin excretion, urinary β2-microglobulin (β2-MG), attenuated the decrease in creatinine clearance rate (CCR). The glomerular sclerosis index (1.54±0.33 compared with 0.36±0.07) and tubulointerstitial fibrosis (1.57±0.31 compared with 0.19±0.04) were significantly higher in SHRs compared with Wistar Kyoto rats (WKYs), which were significantly lower by RSV treatment. The increases in mesangium accumulation and the expression of renal collagen type I (Col I), fibronectin (Fn), plasminogen activator inhibitor-1 (PAI-1) and transforming growth factor-β1 (TGF-β1) in SHR were also reduced by RSV treatment. Nuclear factor κB (NF-κB) expression was increased in the cytoplasm and nuclei of the SHR kidneys, which was significantly decreased by RSV treatment. Furthermore, the protein level of IκB-α significantly decreased in the kidneys of the SHR when compared with the WKYs. RSV treatment partially restored the decreased IκB-α level. In SHR kidney, increased expression of interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein 1 (MCP-1) were observed. These changes were attenuated by RSV treatment. No changes in blood pressure were detected between SHR group and SHR + RSV group. Taken together, the present study demonstrated that RSV treatment may significantly attenuate renal damage in the SHR model of chronic kidney disease (CKD). The renal protective effect is associated with inhibition of IL-6, ICAM-1 and MCP-1 expression via the regulation of the nuclear translocation of NF-κB, which suggesting that micro-inflammation may be a potential therapeutic target of hypertensive renal damage.

Tumor necrosis factor α is a risk factor for infection in peritoneal dialysis patients

BACKGROUND/AIMS

It has been shown that circulating tumor necrosis factor α (TNF-α) is elevated in end stage renal disease patients; however, the relationship between TNF-α and the development of infection in these patients is unknown. In this study, we investigated the association of plasma TNF-α and interleukin 6 (IL-6) with infection in peritoneal dialysis (PD) patients. We also evaluated the association of their plasma levels with the production by peripheral blood mononuclear cells (PBMC), and with various clinical parameters.

METHODS

We enrolled 32 patients on maintenance PD and 10 healthy controls. Plasma and PBMC were isolated from blood. PBMC were stimulated with lipopolysaccharide in vitro.

RESULTS

Mean follow-up duration was 775 days. Six patients developed organ infections (five pneumonia and one liver abscess), and six patients developed PD peritonitis and eight developed exit site infection. Plasma TNF-α and IL-6 levels were significantly elevated in organ infections but not in peritonitis or in exit site infection. Plasma TNF-α was the only significant risk factor for organ infections and pneumonia in multivariate regression analysis. Patients with high plasma TNF-α levels showed a significantly greater cumulative hazard rate for organ infections compared to those with low TNF-α levels. Plasma TNF-α levels correlated with TNF-α production by PBMC and showed an inverse association with Kt/V.

CONCLUSIONS

This is the first study showing that plasma TNF-α is a significant risk factor for infection in PD patients.

Long-term effects of angiotensin II blockade with irbesartan on inflammatory markers in hemodialysis patients: A randomized double blind placebo controlled trial (SAFIR study)

INTRODUCTION

Low-grade chronic inflammation is common in hemodialysis (HD) patients. Previous studies suggest an anti-inflammatory effect of angiotensin II receptor blocker (ARB) treatment. The aim of this study was to compare the effect of ARB vs. placebo on plasma concentrations of inflammatory markers in HD patients.

METHODS

Adult HD patients were randomized for double-blind treatment with the ARB irbesartan 150-300 mg/day or placebo. At baseline, 1 week, 3, 6, 9, and 12 months plasma high sensitivity C-reactive protein (hsCRP), interleukin (IL)-1β, IL-6, IL-8, IL-18, and transforming growth factor-β (TGF-β) were measured using Luminex and enzyme-linked immunosorbent assay (ELISA) technology.

FINDINGS

Eighty-two patients were randomized (placebo/ARB: 41/41). The groups did not differ in initial levels of any of the inflammatory markers (placebo/ARB median(range)): hsCRP 3.3(0.2-23.4)/2.7(0.2-29.6) μg/mL; IL-1β 1.1(0.0-45.9)/1.1(0.0-7.2) pg/mL; IL-6 10(1-90)/12(1-84) pg/mL; IL-8 31(9-134)/34(5-192) pg/mL; IL-18 364(188-1343)/377(213-832) pg/mL; TGF-β 3.2(0.8-13.9)/3.6(1.3-3.8) ng/mL. Overall, there was no significant difference in hsCRP, IL-6, IL-8, and TGF-β between placebo and ARB-treated patients during the study period, and hsCRP, IL-6, IL-8, and TGF-β were relatively stable during the study period (P ≥ 0.18 in all tests for parallel curves, equal levels, and constant levels). The IL-1β level was slightly different in the two groups over time, but not significantly (P = 0.09 in test for parallel curves) and it was also relatively stable during the study period (P ≥ 0.49 in tests for equal levels and constant level). IL-18 was the only inflammatory marker which was not constant during the study period (P = 0.001 in test for constant level), but there was no significant difference between placebo and ARB-treated (P ≥ 0.51 in tests for parallel curves and equal levels).

DISCUSSION

Inflammatory biomarkers were neither acutely, nor in the long-term significantly affected by the ARB irbesartan. Our findings suggest that ARB treatment in HD patients does not offer protective anti-inflammatory effects.

The Association between Nutritional Markers and Biochemical Parameters and Residual Renal Function in Peritoneal Dialysis Patients

Residual renal function (RRF) is an important prognostic factor for peritoneal dialysis patients as it influences the quality of life and mortality. This study was conducted to explore the potential factors correlated with RRF. A cross-sectional study was conducted by recruiting 155 patients with residual GFR more than 1mL/min per 1.73m2 at the initiation of peritoneal dialysis. We collected the demographic characteristics, nutritional markers and biochemical parameters of all participants, and analyzed the correlation between these variables and residual GFR as well. The odds ratio of RRF loss associated with each of the nutritional markers and biochemical parameters were estimated by logistic regression model. The residual GFR was negatively correlated with serum phosphate (ORQ3 = 2.67, 95%CI: 1.03-6.92; ORQ4 = 3.45, 95%CI: 1.35-9.04), magnesium (ORQ4 = 3.77, 95%CI: 1.48-3.63), and creatinine (ORQ3 = 2.93, 95%CI: 1.09-7.88; ORQ4 = 8.64 95%CI: 2.79-26.78), while positively associated with normalized protein catabolic rate (ORQ3 = 0.24, 95%CI: 0.09-0.65; ORQ4 = 0.11, 95%CI: 0.03-0.35), 24 hours urine volume(ORQ1 = 22.87, 95%CI: 2.76-189.24; ORQ3 = 0.08, 95%CI: 0.02-0.28) and serum chlorine concentrations (ORQ1 = 5.34, 95%CI: 1.94-14.68; ORQ4 = 0.28, 95%CI: 0.09-0.85), respectively. Our study suggested that the nutritional markers and biochemical parameters, though not all, but at least in part were closely correlated with RRF in peritoneal dialysis patients.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Association between serum visfatin and carotid atherosclerosis in diabetic and non-diabetic patients on maintenance hemodialysis

Introduction

Adipose tissue releases bioactive factors termed adipokines. Visfatin is an adipokine that plays an active role promoting vascular inflammation and atherosclerosis. The purpose of this study was to determine the association between serum visfatin levels and carotid atherosclerosis in diabetic and non-diabetic patients on maintenance hemodialysis (HD) in order to clarify the role of serum visfatinas, a risk factor for cardiovascular complications in HD patients.

Methods

Forty patients on maintenance hemodialysis were enrolled in this case-control study in 2015. They were subdivided into two groups, i.e., a diabetic group (n = 20) and a non-diabetic group (n = 20). Twenty healthy subjects who were age and gender matched were included as a control group. Carotid Duplex studies were performed on all patients, and serum visfatin was determined by a competitive enzyme immunoassay.

Results

HD patients showed a highly significant increase in serum visfatin, urea, creatinine, Ca×Ph, K, fasting glucose, triglycerides, LDL levels, and a significant decrease in eGFR, Na, HDL, and Hb compared to the control group. Also, serum visfatin levels showed a highly significant increase in the diabetic HD group compared to both the non-diabetic HD and control groups. Serum visfatin showed a highly significant increase in non-diabetic HD patients compared to the control group. Carotid intima-media thickness (IMT) showed a highly significant increase in HD group compared to the control group. Serum visfatin correlated positively with serum urea, creatinine, glucose, and IMT, but it was negatively correlated with eGFR, Na, and HDL

Conclusion

We concluded that serum visfatin is increased in HD patients with and without diabetes. Moreover, its association with IMT may be involved in the pathogenesis of atherosclerosis in CRF patients.

Oxidative stress during erythropoietin hyporesponsiveness anemia at end stage renal disease: Molecular and biochemical studies

Inflammation and oxidative stress are two faces of one coin in end stage renal disease patients (ESRD) on maintenance hemodialysis. Their interconnection induces anemia complicated with erythropoietin hyporesponsiveness. The biochemical bases behind the resistance to erythropoietin therapy with frequent hemoglobinemia, oxidative stress and iron status have not been fully understood. Here two equal groups (40 patients each) of responders and non-responders to recombinant human erythropoietin therapy (higher than 300 IU/kg/wk of epoetin) were investigated. Hematological and biochemical analyses of collected blood and serum samples were performed along with serum electrophoretic protein footprinting. The leukocytic DNA fragmentation was used to evaluate the degree of oxidative insult. The good responders showed lower erythrocyte malondialdehyde (E-MDA) level and less DNA fragmentation of circulating leukocytes than poor responders with elevated hemoglobin, albumin, A/G ratio, total iron, and ferritin levels. Contrariwise, lower erythrocyte superoxide dismutase (E-SOD) and catalase activities in EPO poor responder group were noticed. Neither other serum constituents nor electrophoretic protein pattern showed any difference between the two groups. There were higher levels of inflammatory markers, interleukin-6 (IL6) and C-reactive protein (CRP) in EPO poor responder than good responder. The negative correlations between Hb and both IL6 and CRP levels in the present data remotely indicate a positive correlation between inflammatory markers and severity of anemia. A direct correlation between Hb and antioxidant enzymes (E-SOD and catalase) was noticed, while inverse correlation with E-MDA was recorded. The study proved that oral supplementation of vitamin C to ESRD patients might mitigate the previously elevated serum MDA level in these patients.

Therapeutics targeting persistent inflammation in chronic kidney disease

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

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

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

Interleukin-6 and interleukin-10 as acute kidney injury biomarkers in pediatric cardiac surgery

BACKGROUND

Children undergoing cardiac surgery may exhibit a pronounced inflammatory response to cardiopulmonary bypass (CPB). Inflammation is recognized as an important pathophysiologic process leading to acute kidney injury (AKI). The aim of this study was to evaluate the association of the inflammatory cytokines interleukin (IL)-6 and IL-10 with AKI and other adverse outcomes in children after CPB surgery.

METHODS

This is a sub-study of the Translational Research Investigating Biomarker Endpoints in AKI (TRIBE-AKI) cohort, including 106 children ranging in age from 1 month to 18 years undergoing CPB. Plasma IL-6 and IL-10 concentrations were measured preoperatively and postoperatively [day 1 (within 6 h after surgery) and day 3].

RESULTS

Stage 2/3 AKI, defined by at least a doubling of the baseline serum creatinine concentration or dialysis, was diagnosed in 24 (23%) patients. The preoperative IL-6 concentration was significantly higher in patients with stage 2/3 AKI [median 2.6 pg/mL, interquartile range (IQR) 2.6 0.6-4.9 pg/mL] than in those without stage 2/3 AKI (median 0.6 pg/mL, IQR 0.6-2.2 pg/mL) (p = 0.03). After adjustment for clinical and demographic variables, the highest preoperative IL-6 tertile was associated with a sixfold increased risk for stage 2/3 AKI compared with the lowest tertile (adjusted odds ratio 6.41, 95 % confidence interval 1.16-35.35). IL-6 and IL-10 levels increased significantly after surgery, peaking postoperatively on day 1. First postoperative IL-6 and IL-10 measurements did not significantly differ between patients with stage 2/3 AKI and those without stage 2/3 AKI. The elevated IL-6 level on day 3 was associated with longer hospital stay (p = 0.0001).

CONCLUSIONS

Preoperative plasma IL-6 concentration is associated with the development of stage 2/3 AKI and may be prognostic of resource utilization.

Low Serum Bicarbonate Predicts Residual Renal Function Loss in Peritoneal Dialysis Patients

Low residual renal function (RRF) and serum bicarbonate are associated with adverse outcomes in peritoneal dialysis (PD) patients. However, a relationship between the 2 has not yet been determined in these patients. Therefore, this study aimed to investigate whether low serum bicarbonate has a deteriorating effect on RRF in PD patients.This prospective observational study included a total of 405 incident patients who started PD between January 2000 and December 2005. We determined risk factors for complete loss of RRF using competing risk methods and evaluated the effects of time-averaged serum bicarbonate (TA-Bic) on the decline of RRF over the first 3 years of dialysis treatment using generalized linear mixed models.During the first 3 years of dialysis, 95 (23.5%) patients became anuric. The mean time until patients became anuric was 20.8 ± 9.0 months. After adjusting for multiple potentially confounding covariates, an increase in TA-Bic level was associated with a significantly decreased risk of loss of RRF (hazard ratio per 1 mEq/L increase, 0.84; 0.75-0.93; P = 0.002), and in comparison to TA-Bic ≥ 24 mEq/L, TA-Bic < 24 mEq/L conferred a 2.62-fold higher risk of becoming anuric. Furthermore, the rate of RRF decline estimated by generalized linear mixed models was significantly greater in patients with TA-Bic < 24 mEq/L compared with those with TA-Bic ≥ 24 mEq/L (-0.16 vs -0.11 mL/min/mo/1.73 m, P < 0.001).In this study, a clear association was found between low serum bicarbonate and loss of RRF in PD patients. Nevertheless, whether correction of metabolic acidosis for this indication provides additional protection for preserving RRF in these patients is unknown. Future interventional studies should more appropriately address this question.

The role of klotho on vascular calcification and endothelial function in chronic kidney disease

Recent insights into novel roles of klotho in vascular biology make this primarily kidney-derived protein a possible candidate to form a link between chronic kidney disease and cardiovascular morbidity and mortality. Typical features of vascular dysfunction or structural abnormalities in the arterial wall are exacerbated in klotho-deficient states. Reported klotho functions include inhibition of local phosphate transport in vascular cells, phenotypic switches of vascular cellular elements into bone-forming cells, attenuation of matrix mineralization and calcification, and also preservation of endothelial functional properties and viability. To a large extent these insights rely on animal models of kidney or cardiovascular diseases. In this review the current state of knowledge on these issues is summarized, and we aim to provide a possible new perspective on cardiovascular disease in chronic kidney disease.

Uremic Toxins Induce ET-1 Release by Human Proximal Tubule Cells, which Regulates Organic Cation Uptake Time-Dependently

In renal failure, the systemic accumulation of uremic waste products is strongly associated with the development of a chronic inflammatory state. Here, the effect of cationic uremic toxins on the release of inflammatory cytokines and endothelin-1 (ET-1) was investigated in conditionally immortalized proximal tubule epithelial cells (ciPTEC). Additionally, we examined the effects of ET-1 on the cellular uptake mediated by organic cation transporters (OCTs).

Exposure of ciPTEC to cationic uremic toxins initiated production of the inflammatory cytokines IL-6 (117 ± 3%, p < 0.001), IL-8 (122 ± 3%, p < 0.001), and ET-1 (134 ± 5%, p < 0.001). This was accompanied by a down-regulation of OCT mediated 4-(4-(dimethylamino)styryl)-N-methylpyridinium-iodide (ASP⁺) uptake in ciPTEC at 30 min (23 ± 4%, p < 0.001), which restored within 60 min of incubation. Exposure to ET-1 for 24 h increased the ASP⁺ uptake significantly (20 ± 5%, p < 0.001). These effects could be blocked by BQ-788, indicating activation of an ET-B-receptor-mediated signaling pathway. Downstream the receptor, iNOS inhibition by (N(G)‐monomethyl‐l‐arginine) l-NMMA acetate or aminoguanidine, as well as protein kinase C activation, ameliorated the short-term effects.

These results indicate that uremia results in the release of cytokines and ET-1 from human proximal tubule cells, in vitro. Furthermore, ET-1 exposure was found to regulate proximal tubular OCT transport activity in a differential, time-dependent, fashion.

An intradialytic increase in serum interleukin-6 levels is associated with an increased mortality in hemodialysis patients

BACKGROUND

The inflammatory marker interleukin-6 (IL-6) increases early in the inflammatory cascade. The aim of this study was to evaluate whether an increase in serum IL-6 levels during a hemodialysis (HD) session is associated with mortality.

METHODS

57 adult patients treated with HD for more than 1 month were prospectively studied over a 3-year follow-up period. Demographic and clinical data were collected and blood samples were drawn before and after a midweek HD session. Events of death and censoring were recorded.

RESULTS

During the 3-year follow-up, 50.8% of the patients died. In univariate Cox regression analysis, an increase in IL-6 levels during HD was associated with an increased mortality (HR 1.41 per pg/ml; 95% CI 1.06 to 1.88; P = .017). In multivariate Cox models, the only independent predictors of all-cause mortality were: an increase in IL-6 levels during dialysis (HR 1.46 per pg/ml; 95% CI 1.08 to 1.98; P = .014), higher baseline C-reactive protein (CRP) levels and older age. When predictors of an increase in serum IL-6 levels during HD were introduced into the model, mortality was still significantly associated with IL-6 elevation during dialysis (HR 1.47 per pg/ml, 95% CI 1.01 to 2.14; P = .045).

CONCLUSIONS

A rise in serum IL-6 levels during a single HD session is associated with a higher mortality among HD patients, independent of predialysis CRP or IL-6 levels. The results may imply the presence of an intradialytic inflammatory response that affects survival in HD patients.

Clinical impact of kidney function on presepsin levels

OBJECTIVE

Presepsin is highlighted as a diagnostic and prognostic marker of sepsis. Little information is available regarding the accurate association between presepsin levels and the degree of kidney function. We analyzed presepsin levels in patients with a glomerular filtration rate (GFR) in the categories G1 to G5, evaluated via inulin renal clearance test, and receiving hemodialysis (HD).

METHODS

Patients who were not receiving HD were included if they had undergone inulin renal clearance measurements for the accurate measurement of GFR (measured GFR), and patients who were receiving hemodialysis (HD) were included if they had anuria. Exclusion criteria were infection, cancer, liver disease, autoimmune disorders, or steroid or immunosuppressant use. GFR category was defined as follows; G1: GFR ≥ 90 ml/min/1.73 m2, G2: GFR = 60 to 90 ml/min/1.73 m2, G3: GFR = 30 to 60 ml/min/1.73 m2, G4: GFR = 15 to 30 ml/min/1.73 m2, G5: GFR ≤ 15 ml/min/1.73 m2.

RESULTS

Seventy-one patients were included. The median (IQR) presepsin values of patients in each GFR category were as follows: G1 + G2: 69.8 (60.8-85.9) pg/ml; G3: 107.0 (68.7-150.0) pg/ml; G4: 171.0 (117.0-200.0) pg/ml; G5: 251.0 (213.0-297.5) pg/ml; and HD: 1160.0 (1070.0-1400.0) pg/ml. The log-transformed presepsin values, excluding patients receiving HD, inversely correlated with the measured GFR (Pearson's correlation coefficient = -0.687, P < 0.001). The multivariate analysis revealed that measured GFR and hemoglobin levels significantly correlated with elevated presepsin levels.

CONCLUSION

Presepsin levels were markedly high in patients receiving HD, similar to values seen in patients with severe sepsis or septic shock. In patients who were not receiving HD, presepsin levels increased as GFR decreased. Thus, the evaluation of presepsin levels in patients with chronic kidney disease requires further consideration, and a different cutoff value is needed for diagnosing sepsis in such patients.

Inflammation is associated to volume status in peritoneal dialysis patients

AIM

The aim of this study is to investigate whether there is a relationship between inflammation and volume status in patients underwent peritoneal dialysis (PD).

PATIENTS AND METHOD

This cross-sectional study included 159 PD patients. The median duration of PD was 17 (range, 1-151) months. All patients were examined using bioelectrical impedance analysis to estimate the ratio of extracellular water to total body water (ECW/TBW), which was used to assess their volume status. The patients were categorized as having one of the following three volume statuses: hypervolemic (above +2 SD from the mean, which was obtained from healthy controls), normovolemic (between +2 SD and -2 SD), or hypovolemic (below -2 SD from the mean). Five patients with hypovolemia were excluded from the study. Fifty-six patients were hypervolemic whereas 98 patients were euvolemic. High-sensitive C-reactive protein (hs-CRP) levels were measured to evaluate inflammation in all patients.

RESULTS

hs-CRP value levels were significantly higher in hypervolemic patients compared with euvolemic patients [7.1 (3.1-44.0) mg/L vs. 4.3 (3.1-39.6), p: 0.015, respectively]. Left ventricular hypertrophy was more frequent in hypervolemic patients compared with euvolemic patients (53.6% vs. 30.6%, p: 0.004, respectively). ECW/TBW ratio positively correlated with hs-CRP (r: 0.166, p: 0.039). Gender, hs-CRP, and residual Kt/V urea were found to be independent risk factors for hypervolemia in multivariate analysis.

CONCLUSION

Inflammation is associated with hypervolemia in PD patients. Residual renal functions play an important role to maintain euvolemia in PD patients.

Monocyte and plasma expression of TAM ligand and receptor in renal failure: Links to unregulated immunity and chronic inflammation

Chronic inflammation is increased in patients with chronic kidney disease (CKD) and contributes to cardiovascular morbidity and mortality. Specific immune mechanisms and pathways that drive and maintain chronic inflammation in CKD are not well described. The TAM ligands (Gas6 and protein S) and receptors (Axl and Mer) have been recently recognized as playing a prominent role in immune regulation. The receptors exist in both soluble and cell-bound forms; the soluble receptors (sAxl and sMer) are believed to compete with the bound receptors and thus inhibit their function. In this study, we determined the expression of cell-bound and soluble TAM proteins in patients with CKD. CKD patients had significantly lower expression of Mer in monocytes, yet increased expression of soluble TAM receptors sAxl and sMer in plasma compared to controls. The metalloproteinase ADAM 17, responsible for cleavage of Mer to its soluble form, was increased in patient monocytes. Elevated levels of soluble TAM receptors were more evident in patients with progressive renal failure. These observations suggest that functional deficiency of TAM receptor-mediated regulation of inflammation may contribute to chronic inflammation in patients with CKD.

Chronic kidney disease influences multiple systems: describing the relationship between oxidative stress, inflammation, kidney damage, and concomitant disease

Chronic kidney disease (CKD) is characterized by increased levels of oxidative stress and inflammation. Oxidative stress and inflammation promote renal injury via damage to molecular components of the kidney. Unfortunately, relationships between inflammation and oxidative stress are cyclical in that the inflammatory processes that exist to repair radical-mediated damage may be a source of additional free radicals, resulting in further damage to renal tissue. Oxidative stress and inflammation also have the ability to become systemic, serving to injure tissues distal to the site of original insult. This review describes select mediators in the exacerbatory relationship between oxidative stress, inflammation, and CKD. This review also discusses oxidative stress, inflammation, and CKD as they pertain to the development and progression of common CKD-associated comorbidities. Lastly, the utility of several widely accessible and cost-effective lifestyle interventions and their ability to reduce oxidative stress and inflammation are discussed and recommendations for future research are provided.

Dysfunctional high-density lipoproteins in children with chronic kidney disease

OBJECTIVES

Our aim was to determine if chronic kidney disease (CKD) occurring in childhood impairs the normally vasoprotective functions of high-density lipoproteins (HDLs).

MATERIALS AND METHODS

HDLs were isolated from children with end-stage renal disease on dialysis (ESRD), children with moderate CKD and controls with normal kidney function. Macrophage response to HDLs was studied as expression of inflammatory markers (MCP-1, TNF-α, IL-1β) and chemotaxis. Human umbilical vein endothelial cells were used for expression of adhesion molecules (ICAM-1, VCAM-1, E-selectin) and adhesion. Cellular proliferation, apoptosis, and necrosis of endothelial cells were measured by MTS/PMS reagent-based assay, flow cytometry, and ELISA. Cholesterol efflux was assessed by gas chromatographic measurements of cholesterol in macrophages exposed to HDLs.

RESULTS

Compared with HDL(Control), HDL(CKD) and HDL(ESRD) heightened the cytokine response and disrupted macrophage chemotaxis. HDL(Control) reduced endothelial expression of ICAM-1, VCAM-1, E-selectin, whereas HDL(CKD) and HDL(ESRD) were less effective and showed reduced capacity to protect endothelial cells against monocyte adhesion. Compared with a dramatically enhanced endothelial proliferation following injurious stimulus by HDL(Control), neither HDL(CKD) nor HDL(ESRD) caused proliferative effects. HDLs of all three groups were equally protective against apoptosis assessed by flow cytometry and cleaved caspase-3 activity. Compared to HDL(Control), HDL(CKD) and HDL(ESRD) trended toward reduced capacity as cholesterol acceptors.

CONCLUSION

CKD in children impairs HDL function. Even in the absence of long-standing and concomitant risk factors, CKD alters specific HDL functions linked to control of inflammation and endothelial responses.

Association between renal function, erectile function and coronary artery disease: detection with coronary angiography

Purpose

Many patients admitted for acute myocardial infarction (AMI) have chronic renal insufficiency and erectile dysfunction (ED). This study aimed to evaluate the relationship between ED and the glomerular filtration rate (GFR) in patients with coronary artery disease.

Materials and Methods

We studied 183 patients undergoing coronary angiography owing to AMI. The GFR was calculated and the International Index of Erectile Function-5 (IIEF-5) was used to evaluate ED. The relations between erectile function, GFR, and the number of occluded coronary arteries were evaluated.

Results

Of 183 patients with a mean age of 55.2±11.16 years who underwent coronary angiography owing to AMI, 100 (54.64%) had ED. The ED rate was 45.36% (44/97) in patients with single-vessel disease, 64.5% (31/48) in patients with two-vessel disease, and 65.7% (25/38) in patients with three-vessel disease. The ED rate in patients with single-vessel disease was significantly lower than in the other groups (p<0.001). The mean IIEF scores were 24.2±4.3, 20.4±4.9, and 20.5±4.2 in the three groups, respectively (p<0.001). Mean GFRs were similar in patients with single-vessel disease, two-vessel disease, and three-vessel disease (128.2±46.8, 130.8±70.9, and 110.8±44.6, respectively, p=0.171). The GFR was significantly lower in the presence of ED only for single-vessel disease (p=0.001).

Conclusions

This study confirmed that the presence and severity of ED are linked to the number of occluded vessels as documented by coronary angiography. The presence of ED and reduced GFR are associated with single-vessel coronary artery disease. This relationship can be used to predict the likelihood of coronary artery disease.

Cardiac, Inflammatory and Metabolic Parameters: Hemodialysis versus Peritoneal Dialysis

INTRODUCTION

Mortality in dialysis patients is higher than in the general population, and cardiovascular disease represents the leading cause of death. Hypertension and volume overload are important risk factors for the development of left ventricular hypertrophy (LVH) in hemodialysis (HD) and peritoneal dialysis (PD) patients. Other factors are mainly represented by hyperparathyroidism, vascular calcification, arterial stiffness and inflammation. The aim of this study was to compare blood pressure (BP) and metabolic parameters with cardiovascular changes [cardiothoracic ratio (CTR), aortic arch calcification (AAC) and LV mass index (LVMI)] between PD and HD patients.

MATERIALS AND METHODS

45 patients (23 HD and 22 PD patients) were enrolled. BP measurements, echocardiography and chest X-ray were performed in each patient to determine the LVMI and to evaluate the CTR and AAC. Inflammatory indexes, intact parathyroid hormone (iPTH) and arterial blood gas analysis were also evaluated.

RESULTS

LVMI was higher in PD than HD patients (139 ŷ 19 vs. 104 ŷ 22; p = 0.04). In PD patients, a significant correlation between iPTH, C-reactive protein and the presence of LVH was observed (r = 0.70, p = 0.04; r = 0.70, p = 0.03, respectively). The CTR was increased in PD patients as compared to HD patients, while no significant differences in cardiac calcifications were determined.

CONCLUSIONS

Our data indicate that HD patients present more effective BP control than PD patients. Adequate fluid and metabolic control are necessary to assess the adequacy of BP, which is strongly correlated with the increase in LVMI and with the increased CTR in dialysis patients. PD is a home therapy and allows a better quality of life, but PD patients may present a further increased cardiovascular risk if not adequately monitored.

Intersection of cardiovascular disease and kidney disease: atrial fibrillation

PURPOSE OF REVIEW

Atrial fibrillation is the most common sustained arrhythmia in patients with kidney disease. The purpose of this review is to describe the burden of atrial fibrillation in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD), postulate possible mechanisms to explain this burden of disease, understand the clinical consequences of atrial fibrillation and review the treatment options for atrial fibrillation specific to patients with kidney disease.

RECENT FINDINGS

Recent literature has revealed that the clinical multiorgan impact of atrial fibrillation in patients with CKD and ESRD is substantial. Although novel oral anticoagulants to treat atrial fibrillation and prevent associated complications have been tested in large trials in the general population, there is a paucity of data on the efficacy and safety of these agents in patients with advanced CKD and ESRD.

SUMMARY

Atrial fibrillation is a significant comorbidity in patients with CKD and ESRD with important prognostic implications. More research is needed to understand the mechanisms that contribute to the disproportionate burden of this arrhythmia in patients with kidney disease and in to treatment options specific to this population of high-risk patients.

The progress of inflammation and oxidative stress in patients with chronic kidney disease

BACKGROUND

The variations and their correlation of inflammation and oxidative stress in chronic kidney disease (CKD) have not been thoroughly understood.

MATERIALS AND METHODS

Biomarkers of inflammation and oxidative stress were measured in a cohort of 176 patients with CKD ranging from stage 1 to 5 and 67 healthy controls. Correlation analysis in levels between inflammation and oxidative stress was also performed with estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease (MDRD) formula. Concentrations of serum creatinine (Scr), hs-CRP (hypersensitive C reactive protein) and MDA (malondialdehyde) of these participants were measured again after 12 month follow-up.

RESULTS

In the present study, with the development of CKD, serum levels of hs-CRP, interleukin-6 (IL-6) and MDA were significantly increased, and the serum levels of SOD (superoxide dismutase) and GSH-PX (glutathione peroxidase) were significantly decreased in these participants. eGFR was inversely associated with MDA and positively with SOD and GSH-PX when adjusting for age and hypertension therapy. IL-6 and hs-CRP were positively correlated with MDA, and negatively associated with SOD and GSH-PX. Notably, after 12-month follow-up, the increase in Scr was positively associated with the increase in hs-CRP (p < 0.01) and MDA (p < 0.05), respectively.

CONCLUSIONS

Inflammation and oxidative stress interacted with each other and played pivotal roles in the development of CKD. Variation in eGFR was parallel with the changes of oxidative stress and inflammation when CKD developing.

T-cell ageing in end-stage renal disease patients: Assessment and clinical relevance

End-stage renal disease (ESRD) patients have a defective T-cell-mediated immune system which is related to excessive premature ageing of the T-cell compartment. This is likely to be caused by the uremia-associated pro-inflammatory milieu, created by loss of renal function. Therefore, ESRD patients are highly susceptible for infections, have an increased risk for virus-associated cancers, respond poorly to vaccination and have an increased risk for atherosclerotic diseases. Three ageing parameters can be used to assess an immunological T-cell age. First, thymic output can be determined by assessing the T-cell receptor excision circles-content together with CD31 expression within the naïve T cells. Second, the telomere length of T cells and third the T-cell differentiation status are also indicators of T-cell ageing. Analyses based on these parameters in ESRD patients revealed that the immunological T-cell age is increased by on average 20 years compared to the chronological age. After kidney transplantation (KTx) the aged T-cell phenotype persists although the pro-inflammatory milieu is diminished. This might be explained by epigenetic modifications at hematopoietic stem cells level. Assessment of an immunological T-cell age could be an important tool to identify KTx recipients who are at risk for allograft rejection or to prevent over-immunosuppression.

Effect of anti-tumor necrosis factor alpha treatment of rheumatoid arthritis and chronic kidney disease

Although chronic kidney disease (CKD) may constitute a chronic inflammatory state indicated by elevated inflammatory mediators such as tumor necrosis factor alpha (TNF-α), the impact of anti-TNF-α therapy on progression of CKD in patients with rheumatoid arthritis (RA) is unclear. Seventy patients with RA and CKD were retrospectively analyzed. Outcomes were evaluated using the difference in the annual change of estimated glomerular filtration rate (eGFR) between patients treated with anti-TNF-α or without. Anti-TNF-α therapy significantly decreased disease activity score (DAS) 28 from 5.32 ± 0.78 to 3.59 ± 0.85 (p < 0.001). There was a tendency toward stabilization of eGFR after a mean of 2.9 ± 1.1 years from 50.3 ± 8.4 ml/min/1.73 m(2) to 54.5 ± 16.0 ml/min/1.73 m(2) in patients received anti-TNF-α therapy along with decreased DAS28 (p = 0.084). Conversely, eGFR decreased significantly in patients not receiving anti-TNF-α therapy after a mean of 2.8 ± 1.7 years from 52.6 ± 7.5 ml/min/1.73 m(2) to 46.5 ± 11.5 ml/min/1.73 m(2) (p = 0.041) without significant DAS28 change (p = 0.078). The annual change of eGFR was significantly different between patients treated with anti-TNF-α drugs and without (2.0 ± 7.0 ml/min/1.73 m(2)/year vs. -1.9 ± 4.0 ml/min/1.73 m(2)/year; difference in mean vs. -3.9 ± 7.3 ml/min/1.73 m(2)/year; p = 0.006). Use of anti-TNF-α drugs was significantly associated with positive annual change of eGFR in multivariate logistic regression analysis (p = 0.019). Among patients with RA and CKD, treatment with anti-TNF-α drugs was associated with less renal function decline. Anti-TNF-α drugs may be beneficial for managing RA combined with CKD.

The association between dialysis modality and the risk for dialysis technique and non-dialysis technique-related infections

BACKGROUND

Infections are a major cause of morbidity and mortality among dialysis patients. Dialysis modality has been hypothesized to be a potential immunomodulatory factor. The objective of this study was to determine the influence of the first dialysis modality on the risk for infections on dialysis.

METHODS

Our study was conducted utilizing the Netherlands Cooperative Study on the Adequacy of Dialysis (NECOSAD) cohort of incident dialysis patients. Medical records of all patients from two tertiary care university hospitals and three regional hospitals were reviewed using pre-specified criteria. Information about infections was collected from the start of dialysis until death, modality switch, study withdrawal, kidney transplantation or at the end of the study. Age-standardized incidence rates for infections were calculated. Poisson regression analysis was used to calculate adjusted incidence rate ratios (IRRs).

RESULTS

In total, 452 patients, of whom 285 started with haemodialysis (HD) and 167 with peritoneal dialysis (PD), were included. The median follow-up time on the first dialysis modality was similar for HD and PD, 1.8 and 2.0 dialysis years, respectively. During the first 6 months, the age-standardized infection incidence rate was higher on HD compared with PD patients (P = 0.02). Overall, PD patients had a higher infection risk [adjusted IRR: 1.65, 95% confidence interval (CI): 1.34-2.03], which could be attributed to a 4-fold increased risk for dialysis technique-related infections. The risk for non-dialysis technique-related infections was lower in PD patients (adjusted IRR: 0.56, 95% CI: 0.40-0.79).

CONCLUSIONS

Overall, PD patients carry a higher risk for infections. Interestingly, the risk for non-dialysis technique-related infections was higher in HD patients. The links between dialysis modality and the immune system are expected to explain this difference, but future studies are needed to test these assumptions.

Cross-talk between endothelin-1 and mineral metabolism in hemodialysis patients: a cross-sectional study

Background:

Endotheline-1 (ET-1), an endothelial mediator, influences on mineral metabolism; especially vascular calcification in uremic patients.

Objectives:

The aim of the present study was to evaluate of ET-1, high-sensitivity C-reactive protein (hs-CRP) and mineral metabolites as the main factors for vascular calcification and inflammation in hemodialysis (HD) patients.

Patients and Methods:

In this cross-sectional study, 46 chronic stable HD patients were selected from nephrology departments of Tabriz University of Medical Sciences affiliated hospitals and classified based on phosphorus (P), Ca-P product (Ca × P) and intact Parathyroid Hormone (iPTH) levels. We evaluated fasting serum ET-1and hs-CRP levels by the standard methods and compared with 46 healthy control subjects.

Results:

The levels of serum hs-CRP and ET-1 were significantly higher in the patient’s group compared with controls (4.40 ± 1.26 vs. 1.38 ± 1.61, P < 0.0001, and 2.31 ± 0.87 vs. 0.75 ± 0.48, P < 0.0001, respectively) and with regard to Ca × P product cut-off point (3.99 ± 0.78 vs. 5.33 ± 1.64, P < 0.0001, and 2 ± 0.73 vs. 3.04 ± 0.73, P < 0.0001 respectively). ET-1 was correlated significantly with hs-CRP level (r = 0.776, P < 0.0001). Serum P, Ca × P and iPTH levels directly and Ca indirectly were correlated with serum ET-1 in HD patients (r = 0.932, P < 0.0001, r = 0.766, P < 0.0001, r = 0.514, P < 0.0001, r = -0.538, P < 0.0001 respectively). Multiple regression analysis demonstrated that serum P were independently associated with ET-1 levels (β = 0.932, P < 0.0001).

Conclusions:

Serum P and iPTH levels were independently associated with ET-1 and those may play a role in development of endothelial dysfunction in chronic kidney disease.

Association between depression and inflammatory/anti-inflammatory cytokines in chronic kidney disease and end-stage renal disease patients: a review of literature

Depression is a common psychiatric disorder in patients with advanced chronic kidney diseases (CKDs). Strong correlation has been reported between depression and patients' morbidity and mortality among dialysis patients. On the contrary, chronic inflammation may be a major contributor to morbidity and mortality in these patients. Elevated plasma levels of proinflammatory cytokines, especially C-reactive protein and interleukin (IL)-6, have been correlated with cardiovascular events, hospitalization, and all-cause and cardiovascular-associated mortality in dialysis patients. Studies suggested that inflammation-mediated atherosclerotic cardiovascular diseases are the possible reasons for depression-induced mortality among patients without renal diseases. Several studies found significant elevations in circulating levels of proinflammatory cytokines, particularly IL-6 and tumor necrosis factor-α, in patients with major depression. Furthermore, depressive mood and behaviors, including sadness and suicidal ideation, were observed in patients who received repeated injections of recombinant cytokines. A thorough literature review indicates that while depressive symptoms and elevated inflammatory cytokine levels coexist in CKD and dialysis patients, their association is uncertain. Depression seems to be more associated with elevated serum levels of IL-6 than other cytokines in these patients. Further studies are needed to clarify the possibility of a causal relationship between inflammation and depressive symptoms in CKD and dialysis patients.

Inflammation and myocardial damage markers influence loss of residual renal function in peritoneal dialysis patients

BACKGROUND

Residual renal function (RRF) has been identified as the most important component in dialysis adequacy and has a strong effect on clinical outcomes. This justifies any effort in understanding the mechanism behind the preservation or decline in RRF. The aim of this study was to analyze the possible association of components of cardio-renal syndrome with the rate of decline in RRF.

METHODS

A retrospective cohort study was performed in a group of prevalent adult patients on continuous ambulatory peritoneal dialysis (CAPD). Patients were analyzed at baseline and after a 30-month follow-up. Evaluations included measurements of residual renal function, dialysis adequacy parameters, cardiovascular comorbidity, and measurements of biochemical markers of cardiovascular disease (CVD) and inflammation, as well as resting electrocardiography.

RESULTS

We included 129 patients in the study who were divided into groups according to loss of RRF, considering the cut-off point as 100 mL/day of 24 h urine volume. At baseline, there were no differences between groups: patients who lost RRF showed low values of 24 h urine volume, higher levels of systolic blood pressure, N-terminal pro-brain natriuretic peptide (NT-proBNP), C-reactive protein (CRP), IL-6, and low values of serum albumin. In the multivariate analysis, age, albumin, CRP, and NT-proBNP were significant risk factors for the loss of RRF.

CONCLUSIONS

Data indicate a close relationship between heart and kidney function where chronic kidney disease (CKD) affects and is an effect of, heart function, indicative of a bi-directional influence that leads to a vicious cycle, promoting deleterious effects on both systems.

Impact of renal dysfunction on long-term outcomes of elderly patients with acute coronary syndrome: a longitudinal, prospective observational study

Background

This study investigated the impact of renal dysfunction (RD) on long-term outcomes in elderly patients with acute coronary syndrome (ACS), and evaluated prognostic factors in elderly patients with ACS and RD.

Methods

This longitudinal prospective study included 184 consecutive patients who were admitted with ACS between January 2009 and January 2010 and also had RD. Patients were divided into five groups according to their estimated glomerular filtration rate (eGFR): 1) eGFR ≥ 90 mL/min/1.73 m² with evidence of kidney damage, 2) 60 ≤ eGFR < 90 mL/min/1.73 m², 3) 30 ≤ eGFR < 60 mL/min/1.73 m², 4) 15 ≤ eGFR < 30 mL/min/1.73 m², and 5) eGFR < 15 mL/min/1.73 m². The primary endpoints were death and complications during hospitalization. The secondary endpoint was any major adverse cardiac event (MACE) during follow-up.

Results

The mean follow-up period was 502.2 ± 203.6 days. The mean patient age was 73.7 ± 9.4 years, and 61.4% of the patients were men. Severe RD (eGFR < 30 mL/min/1.73 m²) was an independent predictor of MACE. Severe RD was associated with a low hemoglobin level, low left ventricular ejection fraction, and high levels of high-sensitivity C-reactive protein, N-terminal pro-B-type natriuretic peptide, and cystatin C. Survival was significantly poorer in patients with severe RD than in patients with mild RD.

Conclusions

Among patients with ACS, severe RD was associated with advanced age, diabetes, hypertension, and cardiac dysfunction. Severe RD was an independent risk factor for MACE, and was associated with poor prognosis.

Clinical causes of inflammation in peritoneal dialysis patients

Inflammation at both systemic and local intraperitoneal levels commonly affects peritoneal dialysis (PD) patients. Interest in inflammatory markers as targets of therapeutic intervention has been considerable as they are recognised as predictors of poor clinical outcomes. However, prior to embarking on strategies to reduce inflammatory burden, it is of paramount importance to define the underlying processes that drive the chronic active inflammatory status. The present review aims to comprehensively describe clinical causes of inflammation in PD patients to which potential future strategies may be targeted.

Acute kidney injury in rats with or without pre-existing chronic kidney disease: cytokine/chemokine response

AIM

Evidence suggests the possibility that pre-existing chronic kidney (CKD) disease may result in a more severe outcome of acute kidney injury (AKI). The aim of this study was to examine whether CKD enhances the inflammatory response in the kidney, as well as other organs, in response to AKI in rats.

METHODS

CKD was induced by 5/6 nephrectomy (Nx) and AKI by intestinal ischaemia and reperfusion (IIR).

RESULTS

For 6 weeks following Nx there was a progressive increase in serum creatinine with associated development of albuminuria. The increment in creatinine above baseline determination 90 min following IIR was comparable in 5/6 Nx and in the sham 5/6 Nx. Similarly, increased levels of serum alanine transaminase and histomorphological changes in the lungs were observed in the rats exposed to IIR compared with those exposed to sham IIR, with no additional significant impact of 5/6 Nx. In kidney tissue the levels of cytokines/chemokines were equally elevated regardless of exposure to sham IIR or IIR. In lung and liver tissue the levels of cytokines/chemokines were equally elevated in the rats that were exposed to IIR, regardless of exposure to sham Nx or Nx.

CONCLUSION

We conclude that the immediate severity of AKI induced by IIR in rats with CKD is similar to that induced in rats without CKD. However, the impact of Nx on the cytokine/chemokine response after AKI is not uniform in kidney, lung or liver tissue.

Baseline serum interleukin-6 predicts cardiovascular events in incident peritoneal dialysis patients

BACKGROUND

The utility of local and systemic interleukin 6 (IL-6) as a prognostic marker in incident peritoneal dialysis (PD) patients remains to be fully defined. The present study aimed to explore the capacity of systemic IL-6 concentrations to predict cardiovascular events (CVEs) and mortality in PD patients, and to evaluate the influence of neutral-pH PD solutions low in glucose degradation products (GDPs) on systemic IL-6.

METHODS

The study included 175 incident participants from the balANZ trial with at least one stored serum sample. A composite CVE score was used as the primary clinical outcome measure. Multilevel linear regression and Poisson regression models were fitted to describe, respectively, the trend of serum IL-6 over time and its ability to predict composite CVE.

RESULTS

A significant increase in serum IL-6 from baseline to 24 months was observed in the study population (mean difference: 1.68 pg/mL; p = 0.006). The type of PD solution received by patients exerted no significant effect on serum IL-6 (p = 0.12). Composite CVE was significantly and independently associated with baseline serum IL-6 (incidence rate ratio per picogram per milliliter: 1.06; 95% confidence interval: 1.02 to 1.10; p = 0.003).

CONCLUSIONS

Baseline serum IL-6 was a significant independent predictor of composite CVE. Serum IL-6 concentrations increased with increasing PD duration and were not significantly modified with the use of biocompatible fluid over the study period. The present study is the first to link systemic IL-6 concentrations with CVE outcomes in incident PD patients.

Different peptic ulcer bleeding risk in chronic kidney disease and end-stage renal disease patients receiving different dialysis

BACKGROUND

End stage renal disease (ESRD) patients receiving hemodialysis (HD) have a higher risk of peptic ulcer bleeding (PUB).

AIMS

Whether ESRD patients receiving peritoneal dialysis (PD) also carries a higher risk of PUB has not been studied.

METHODS

This was a cohort study using Taiwan's National Health Insurance research database, whereby 11,408 patients, including 2,239 PD, 2,328 HD, 2,267 chronic kidney disease (CKD) and 4,574 controls with age-sex matching were recruited. The log-rank test was used to analyze differences in accumulated PUB-free survival rates between groups. Cox proportional hazard regression was performed to evaluate independent risk factors for PUB in all the enrollees.

RESULTS

During the 7-year follow-up, PD and CKD patients had a significantly higher rate of PUB than matched controls. The risk of PUB between PD and CKD was not significantly different. Moreover, patients receiving HD carried a higher risk of PUB than those receiving PD, with CKD and controls (p all <0.05, by log-rank test). Cox proportional hazard regression analysis showed that CKD (HR 3.99, 95 % CI 2.24-7.13), PD (HR 3.71, 95 % CI 2.00-6.87) and HD (HR 11.96, 95 % CI 7.04-20.31) were independently associated with an increased risk of PUB. Being elderly, male, having hypertension, diabetes, cirrhosis, and nonsteroidal anti-inflammatory drugs and steroid use were other independent risk factors of PUB in all enrollees.

CONCLUSIONS

Patients with CKD and ESRD receiving PD or HD carried a higher risk for PUB. They should be screened for risk factors for PUB and receive some protective measures to prevent PUB.

Determination of oxidative stress and cellular inflammation in patients with diabetic nephropathy and non-diabetic nephropathy being administered hemodialysis treatment due to chronic renal failure

OBJECTIVES

We aimed to evaluate oxidative stress [8-hydroxydeoxyguanosine (8-OHdG), malondialdehyde (MDA)] endothelial damage [asymmetric dimethylarginine (ADMA)] and markers of cellular inflammation [interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), neopterin (NP) and high-sensitivity C-reactive protein (hsCRP)] in patients with diabetic nephropathy (DN) and non-diabetic nephropathy who were being administered hemodialysis treatment because of chronic renal failure.

METHODS

In determining 8-OHdG, IL-6 and TNF-α levels, Enzyme-Linked Immuno-Sorbent Assay method was used. Serum MDA, ADMA and NP levels were determined by using high performance liquid chromatography (HPLC). And hs-CRP values were measured with nephelometric method.

RESULTS

Serum 8-OHdG and MDA levels were found statistically to have increased when compared with those of the control group in patients groups after dialysis. However, serum ADMA and neopterin levels were observed statistically to have decreased when compared with those of the control group in patients groups after dialysis. But, decreases on ADMA and neopterin levels are still much higher than those of control. IL-6 and TNF-α levels were found to have increased when compared with those of control group in patients groups before dialysis.

CONCLUSION

The oxidative stress in patients with DN, who were being treated with hemodialysis due to chronic renal failure, was higher than that of non-DN patients who were being treated with hemodialysis. In contrast with this, inflammation occurring in non-DN patients was found to have been higher than that of in patients with DN.

Impaired renal growth hormone JAK/STAT5 signaling in chronic kidney disease

BACKGROUND

Treatment with recombinant human growth hormone (GH) is the standard therapy for short stature in children with chronic kidney disease (CKD). However, concerns have been raised on the potential renal fibrogenic effects of GH. There is no information regarding the renal GH receptor (GHR)-JAK-STAT signaling pathway in CKD.

METHODS

Subtotal nephrectomized (CKD) and pair-fed sham-operated control (C) juvenile rats were treated with subcutaneous GH or saline for 2 weeks. A single intravenous GH bolus or vehicle was provided prior to euthanasia.

RESULTS

Reduced body weight in CKD was improved with GH therapy. The remnant kidney showed glomerular hypertrophy and early interstitial fibrosis without inflammatory infiltration. Treatment of CKD rats with GH did not worsen renal function or fibrosis. Kidney GHR mRNA and protein levels were reduced and basal phosphorylation of JAK2 and STAT5 was significantly impaired. However, intravenous GH administration prior to sacrifice normalized STAT5 phosphorylation. Basal renal IL6 mRNA and phosphorylation of its downstream signaling molecule STAT3 were increased as was the product of its action, the suppressor of cytokine signaling 3 (SOCS3) mRNA.

CONCLUSIONS

Despite known unaltered circulating GH levels, remnant kidneys of uremic growth retarded juvenile rats show impaired basal signaling along the GH-activated JAK2/STAT5 signaling pathway. This may well be a consequence of the reduced GHR level and the inhibitory effect of the increase in IL-6-mediated SOCS3 expression. This renal GH insensitivity, if present in humans, may protect against the potential adverse renal effects of GH administration in CKD patients.

Serum concentrations of p-cresyl sulfate and indoxyl sulfate, but not inflammatory markers, increase in incident peritoneal dialysis patients in parallel with loss of residual renal function

BACKGROUND

High serum concentrations of the protein-bound uremic retention solutes p-cresyl sulfate (PCS) and indoxyl sulfate (IndS) and inflammation are associated with increased cardiovascular morbidity and mortality in chronic kidney disease. Renal clearance contributes to up to 80% of the total clearance of PCS and IndS in peritoneal dialysis (PD) patients. Cross-sectional studies evaluating the impact of residual renal function (RRF) on serum concentrations of PCS, IndS, and circulating inflammatory markers have yielded conflicting results. ♢

METHODS

To clarify this issue, we carried out a prospective observational cohort study in incident PD patients (n = 35; 19 men; mean age: 55 ± 17 years). Midday blood samples were collected and analyzed for total serum PCS, IndS, C-reactive protein, and high-sensitivity interleukin 6. Peritoneal and renal clearances were calculated from urine and dialysate collections, and RRF was calculated as the mean of renal urea nitrogen and creatinine clearances. Patients were assessed 1, 6, 12, and 24 months after PD start. Differences between time points were analyzed using linear mixed models (LMMs). ♢

RESULTS

Residual renal function declined significantly over time (LMM p < 0.0001). Peritoneal clearances of both toxins tended to increase, but did not compensate for the declining renal clearances. Serum concentrations of PCS and IndS increased significantly over time (LMM p = 0.01; p = 0.0009). In contrast, total mass removal of both toxins remained stable. Circulating inflammatory markers did not change over time. ♢

CONCLUSIONS

Our data indicate that serum concentrations of PCS and IndS, but not inflammatory markers, increase in incident PD patients in parallel with loss of RRF.

Mediators of inflammation and their effect on resident renal cells: implications in lupus nephritis

Lupus nephritis affects up to 70% of patients with systemic lupus erythematosus and is a major cause of morbidity and mortality. It is characterized by a breakdown of immune tolerance, production of autoantibodies, and deposition of immune complexes within the kidney parenchyma, resulting in local inflammation and subsequent organ damage. To date, numerous mediators of inflammation have been implicated in the development and progression of lupus nephritis, and these include cytokines, chemokines, and glycosaminoglycans. Of these, type I interferons (IFNs) can increase both gene and protein expression of cytokines and chemokines associated with lupus susceptibility, and interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and hyaluronan have been shown to elicit both pro- and anti-inflammatory effects on infiltrating and resident renal cells depending on the status of their microenvironment. Expression of IL-6, TNF-α, type I IFNs, and hyaluronan are increased in the kidneys of patients and mice with active lupus nephritis and have been shown to contribute to disease pathogenesis. There is also evidence that despite clinical remission, ongoing inflammatory processes may occur within the glomerular and tubulointerstitial compartments of the kidney, which further promote kidney injury. In this review, we provide an overview of the synthesis and putative roles of IL-6, TNF-α, IFN-α, and hyaluronan in the pathogenesis of lupus nephritis focusing on their effects on human mesangial cells and proximal renal tubular epithelial cells.

Novel biomarkers for the progression of diabetic nephropathy: soluble TNF receptors

Despite 2 decades of advances in therapy of diabetic patients, the prevalence of diabetic nephropathy among patients with diabetes has not decreased. However, large-scale multicenter studies have achieved great success in terms of the reduction of albuminuria, suggesting that albuminuria might not be an accurate surrogate marker for slowing the rate of renal function decline. It is important to be able to identify individuals at high risk for renal function decline, or ultimately, end-stage kidney disease (ESKD) and its associated cardiovascular disease (CVD). More sensitive early biomarkers, other than albuminuria and the estimated glomerular filtration rate (eGFR), should be required. Recently, serum concentrations of soluble tumor necrosis factor (TNF), receptor 1 (TNFR1), and TNFR2 have predicted future GFR loss and ESKD in patients of a wide variety of stages and both types of diabetes. Longitudinal interventional studies are needed to validate these biomarkers in a broad range of populations prior to implementation in routine diabetes management.