Oxidative stress and haemodialysis: role of inflammation and duration of dialysis treatment

Update on Hemodialysis-Induced Multiorgan Ischemia: Brains and Beyond

Hemodialysis is a life-saving treatment for patients with kidney failure. However, patients requiring hemodialysis have a 10-20 times higher risk of cardiovascular morbidity and mortality than that of the general population. Patients encounter complications such as episodic intradialytic hypotension, abnormal perfusion to critical organs (heart, brain, liver, and kidney), and damage to vulnerable vascular beds. Recurrent conventional hemodialysis exposes patients to multiple episodes of circulatory stress, exacerbating and being aggravated by microvascular endothelial dysfunction. This promulgates progressive injury that leads to irreversible multiorgan injury and the well-documented higher incidence of cardiovascular disease and premature death. This review aims to examine the underlying pathophysiology of hemodialysis-related vascular injury and consider a range of therapeutic approaches to improving outcomes set within this evolved rubric.‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬.

Assessment of amino-terminal C-type natriuretic peptide serum level and its correlation with high-density lipoprotein structure and function in patients with end stage renal disease before and after kidney transplantation

We aimed to investigate serum amino-terminal C-type natriuretic peptide (NT-proCNP) and its relationship with quantitative and qualitative HDL-parameters in patients with end-stage renal disease (ESRD) before, then 1 and 6 months after kidney transplantation (TX). Seventy patients (47 males, 23 females, mean age 51.7 ± 12.4 years) were enrolled in a prospective follow-up study. We examined serum creatinine, C-reactive protein, procalcitonin, fasting glucose and lipid parameters before, then 1 and 6 months after TX. High-density lipoprotein- (HDL)-associated paraoxonase-1 (PON1) paraoxonase and arylesterase activities were measured spectrophotometrically. Lipoprotein subfractions were determined by Lipoprint. NT-proCNP and oxidized low-density lipoprotein (oxLDL) levels were measured by ELISA. Mean NT-proCNP was 45.8 ± 21.9 pmol/L before renal transplantation and decreased markedly 1 month and 6 months after transplantation (5.3 ± 2.5 and 7.7 ± 4.9 pmol/L, respectively, P = 1 × 10-4). During the 6 months' follow-up, PON1 arylesterase, paraoxonase and salt-stimulated paraoxonase activities improved. NT-proCNP positively correlated with procalcitonin and creatinine and negatively with GFR, LDL-cholesterol (LDL-C) and HDL-cholesterol (HDL-C). There was a negative correlation between serum NT-proCNP and PON1 arylesterase activity. According to the multiple regression analysis, the best predicting variables of NT-proCNP were serum procalcitonin, creatinine and PON1 arylesterase activity. NT-proCNP might be a novel link between HDL dysfunction and impaired vascular function in ESRD, but not after kidney transplantation. Further studies in larger populations are needed to clarify the exact role of NT-proCNP in the risk prediction for cardiovascular comorbidities and complications in ESRD.

SOD1 is a novel prognostic biomarker of acute kidney injury following cardiothoracic surgery

BACKGROUND

Acute kidney injury (AKI) is a major burden among hospitalized and critical care patients. Among hospitalized patients that progress to severe AKI there is increased risk for morbidity, mortality, and the need for renal replacement therapy (RRT). As there are no specific treatments for AKI, the discovery of novel biomarkers that predict the progression of AKI may aid in timely implementation of supportive care to improve outcomes.

METHODS

We collected urine from 204 patients that developed Stage 1 AKI by AKIN criteria within 72 h following cardiothoracic surgery. Urine samples were collected at the time of the initial diagnosis of AKI and stored at -80° C. Among the 204 patients, 25 progressed to a composite primary outcome of Stage 3 AKI, requirement of RRT, or 30-day mortality. The remaining 179 patients did not progress beyond Stage 2 AKI and were considered controls. Urinary concentrations of SOD1 and SOD1 activity were measured following collection of all samples. Samples were thawed and urinary superoxide dismutase 1 (SOD1) concentrations were measured by sandwich ELISA and urinary SOD1 activity was measured through a commercially available colorimetric assay.

RESULTS

Urinary concentrations of SOD1 were significantly elevated (67.0 ± 10.1 VS 880.3 ± 228.8 ng/ml, p < 0.0001) in patients that progressed to severe AKI and were able to predict the progression to severe AKI (AUC - 0.85, p < 0.0001). Furthermore, total SOD activity also increased in the urine of patients that required RRT (77.6% VS 49.81% median inhibition, p < 0.01) and was able to predict the need for RRT (AUC: 0.83, p < 0.01).

CONCLUSION

These findings show that urinary SOD1 concentrations and SOD activity are novel prognostic biomarkers for severe AKI following cardiothoracic surgery.

The relationship of dietary antioxidant capacity with laboratory and anthropometric measurements in hemodialysis patients

Aim: Dietary antioxidant intake correlates with blood antioxidant content and protects against oxidative damage and related inflammatory complications. This study was conducted to examine the relationship between total antioxidant capacity of diet and effective factors with laboratory and anthropometric parameters in patients undergoing hemodialysis. Material and Method: The present case-control study consisted of 62 cases and 59 controls individuals who received hemodialysis treatment between the ages of 35-75. Dietary intake, sociodemographic data, medical history, and anthropometric measurements were collected from participants using a validated questionnaire. Results: Examining the association between dietary components and diet's total antioxidant capacity (dTAC) reveals a positive correlation between dietary protein (kg/avg), beta carotene (mcg/day), vitamin C (mg/day), vitamin E (mg/day), and polyunsaturated fatty acids (PUFA) (g/day) (p=0.002). The serum albumin, serum neutrophil to lymphocyte ratio and HDL-cholesterol have been reported to have a positive relationship with dTAC. And body mass ındex (BMI) and other anthropometric parameters were found to have a negative connection with dTAC (p=0.007). Conclusion: Total dietary antioxidant capacity is effective on anthropometric measurements and serum laboratory values. Increasing the antioxidant capacity of the diet in hemodialysis patients is important to prevent complications related to inflammation.

A Causal-Pathway Phenotype of Chronic Fatigue Syndrome due to Hemodialysis in Patients with End-Stage Renal Disease

BACKGROUND

End-stage renal disease (ESRD) is associated with fatigue and physiosomatic symptoms.

OBJECTIVE

The objective of this study is to delineate the associations between severity of fatigue and physio-somatic symptoms and glomerular filtration rate, inflammatory biomarkers, and Wnt/cateninpathway proteins.

METHODS

The Wnt-pathway related proteins β-catenin, Dickkopf-related protein 1 (DKK1), R-spondin- 1, and sclerostin were measured by ELISA technique in 60 ESRD patients and 30 controls. The Fibromyalgia and Chronic Fatigue Syndrome (FF) Rating Scale was used to assess the severity of FF symptoms.

RESULTS

ESRD is characterized by a significant increase in the total FF score, muscle tension, fatigue, sadness, sleep disorders, gastro-intestinal (GI) symptoms, and a flu-like malaise. The total-FF score was significantly correlated with serum levels of urea, creatinine, and copper (positively), and β-catenin, eGFR, hemoglobin, albumin, and zinc (inversely). The total-FF score was associated with the number of total dialysis and weekly dialysis sessions, and these dialysis characteristics were more important in predicting FF scores than eGFR measurements. Partial Least Squares analysis showed that the FF score comprised two factors that are differently associated with biomarkers: a) 43.0% of the variance in fatigue, GI symptoms, muscle tension, sadness, and insomnia is explained by hemoglobin, albumin, zinc, β-catenin, and R-spondin-1; and b) 22.3% of the variance in irritability, concentration and memory impairments by increased copper and cations/chloride ratio, and male sex.

CONCLUSION

ESRD patients show high levels of fatigue and physio-somatic symptoms associated with hemodialysis and mediated by dialysis-induced changes in inflammatory pathways, the Wnt/catenin pathway, and copper.

A Comparison Between the Effects of Calcium Acetate and Sevelamer Carbonate on Progression of Aortic Vascular Calcification in Patients with Chronic Kidney Disease Stages 4 and 5

Background: Calcium-based and non-calcium-based phosphate binders are frequently used to treat hyperphosphatemia in patients with chronic kidney disease (CKD). Objectives: This study aimed to compare the effects of calcium acetate and sevelamer carbonate on the progression of aortic vascular calcification in patients with CKD stages 4 and 5. Methods: This was an open-label randomized prospective comparative study, in which the participants encompassed both male and female patients with ambulatory hyperphosphatemic CKD stages 4 and 5 aged above 18 years. One hundred fifty patients with CKD stages 4 and 5 were screened for Aortic vascular calcification using digital X-ray lumbar spine and multi-slice CT scan, of whom fifty patients with vascular calcification were selected and randomly assigned into two groups. The participants were then serially studied for the effects of phosphate binders on the progression of vascular calcification over one year. One group was prescribed calcium acetate, and the other group was prescribed sevelamer carbonate. Results: Fifty hyperphosphatemic CKD patients with a mean age of 57 years were randomly assigned into two groups. There was no statistically significant difference between the two groups; however, the patients assigned to the sevelamer group were older and higher aortic calcification index (ACI) (P = 0.035) and Kauppila scores (P = 0.04), and elevated serum calcium (P = 0.04), Ca X PO4 (P = 0.006), and vitamin D. In calcium acetate-treated patients, the mean ACI increased significantly during six months and one year; however, the increase was not significant in the sevelamer group. Serum cholesterol, serum triglycerides, serum iPTH level, and the inflammatory markers of atherosclerosis high sensitivity of C-reactive protein (hs-CRP), interleukin-6 (IL-6) (hs-CRP, IL-6) decreased significantly in the sevelamer group. Conclusions: The prevalence of vascular (abdominal aortic) calcification in pre-ESRD (CKD stage 4 and 5) patients was 75%. Abdominal aortic calcification increased significantly in calcium acetate-treated patients during six months and one year; however, the progression was not significant regarding sevelamer. Because of its pleiotropic properties, sevelamer is more effective and consistent in retarding the progression of vascular calcification than calcium acetate in patients with CKD stages 4 and 5.

SOD3 and IL-18 Predict the First Kidney Disease-Related Hospitalization or Death during the One-Year Follow-Up Period in Patients with End-Stage Renal Disease

End-stage renal disease (ESRD) patients experience oxidative stress due to excess exogenous or endogenous oxidants and insufficient antioxidants. Hence, oxidative stress and inflammation cause endothelial damage, contributing to vascular dysfunction and atherosclerosis. Therefore, ESRD patients suffer more cardiovascular and hospitalization events than healthy people. This study aims to test the correlations between ROS, SOD3, IL-2, IL-6, and IL-18 and the first kidney disease-related hospitalization or death events in ESRD patients undergoing regular hemodialysis. A total of 212 participants was enrolled, including 45 normal healthy adults and 167 ESRD patients on regular dialysis. Blood samples from all participants were collected for ROS, SOD3, IL-2, IL-6, and IL-18 measurement at the beginning of the study, and every kidney disease-related admission or death was recorded for the next year. Multivariate analysis was conducted by fitting a linear regression model, logistic regression model, and Cox proportional hazards model to estimate the adjusted effects of risk factors, prognostic factors, or predictors on continuous, binary, and survival outcome data. The results showed that plasma SOD3 and serum IL-18 were two strong predictors of the first kidney disease-related hospitalization or death. In the Cox proportional hazards models (run in R), higher IL-18 concentration (>69.054 pg/mL) was associated with a hazard ratio of 3.376 for the first kidney disease-related hospitalization or death (95% CI: 1.2644 to 9.012), while log(SOD3) < 4.723 and dialysis clearance (Kt/V; 1.11 < value < 1.869) had a hazard ratio = 0.2730 (95% CI: 0.1133 to 0.6576) for reducing future kidney disease-related hospitalization or death. Other markers, including body mass index (BMI), transferrin saturation, total iron binding capacity, and sodium and alkaline phosphate, were also found to be significant in our study. These results reveal the new predictors SOD3 and IL-18 for the medical care of end-stage renal disease patients.

Alexithymia, Phosphorus Levels, and Sleep Disorders in Patients on Hemodialysis

Alexithymia, or the inability to distinguish between bodily feelings and emotions, has been linked to poor sleep quality in some studies. Rare studies examined the associations between electrolyte phosphorus in patients on hemodialysis and their sleep quality, daytime sleepiness, and alexithymia with inflammatory factors. Hemodialysis is a treatment method for terminal renal patients that involves the diffusion of unwanted metabolic products through the dialyzer membrane. Our study aimed to examine whether there was a difference in phosphorus levels, inflammatory factors, and daytime sleepiness according to the hemodialysis patients’ levels of alexithymia. The study involved 170 HD patients that had been treated with chronic dialysis for more than three months. Prior to the hemodialysis procedure, laboratory findings were sampled. Respondents completed the Pittsburgh Sleep Quality Index, the Toronto Alexithymia Scale 26, and the Epworth Sleepiness Scale, and were questioned about depression. The results showed that alexithymic HD patients exhibited significantly higher leukocyte counts, lower predialysis phosphorus values, and more pronounced daily sleepiness than the alexithymia-free group (Mann−Whitney U test, p = 0.02, p = 0.005, and p < 0.001, respectively). We concluded that alexithymia was an independent predictor of high daytime sleepiness in HD patients (OR = 1.05, 95% CI 1.02 to 1.09).

Effect of Near-Infrared Blood Photobiomodulation on Red Blood Cell Damage from the Extracorporeal Circuit during Hemodialysis In Vitro

The contact of blood with the bioincompatible membranes of the dialyzer, which is part of the extracorporeal circuit during hemodialysis (HD), causes upregulation of various cellular and non-cellular processes, including massive generation and release of reactive oxygen species (ROS), (which is one of the primary causes of anemia in chronic renal failure). We hypothesize that near-infrared (NIR) radiation possesses antioxidant properties and is considered to protect the red blood cell (RBC) membrane by enhancing its resilience to negative pressures. Our experimental setup consisted of an HD machine equipped with a dialyzer with a polyamide membrane; whole bovine blood was examined in vitro in blood-treated circulation. Blood samples were taken at 0, 5, 15, and 30 min during the HD therapy. We also assessed osmotic fragility, hematocrit, hemolysis, and oxidative stress as a concentration of reactive thiobarbituric acid substances (TBARS). Our results have shown that RBC membrane peroxidation increased significantly after 30 min of circulation, whereas the TBARS level in NIR-treated blood remained relatively steady throughout the experiment. The osmotic fragility of NIR-irradiated samples during dialysis was decreased compared to control samples. Our studies confirm that in vitro, blood photobiomodulation using NIR light diminishes oxidative damage during HD and can be considered a simultaneous pretreatment strategy for HD.

Effect of Nigella Sativa Oil on Oxidative Stress, Inflammatory, and Glycemic Control Indices in Diabetic Hemodialysis Patients: A Randomized Double-Blind, Controlled Trial

Background and Aims

Diabetes is a leading cause of renal failure. High levels of oxidative stress and inflammation in patients with renal diabetes lead to various disorders and mortality. This study was performed to determine the effect of Nigella sativa (NS) supplementation on superoxide dismutase (SOD), malondialdehyde (MDA), total antioxidant capacity (TAC), high-sensitivity C-reactive protein (hs-CRP), glycosylated hemoglobin (HbA1c), fasting blood sugar (FBS), and insulin (INS) in patients with diabetes mellitus undergoing hemodialysis (HD).

Methods

In this randomized, double-blind, placebo-controlled clinical trial, a total of 46 diabetic HD patients were randomly divided into NS (n = 23) and placebo (n = 23) groups. NS group received 2 g/day of NS oil, and the placebo group received paraffin oil for 12 weeks. Serum levels of SOD, MDA, TAC, hs-CRP, HbA1C, FBS, and INS were measured before and after the study.

Results

Compared to baseline values, SOD, TAC, and INS levels increased, whereas MDA, hs-CRP, HbA1c, and FBS significantly decreased. After adjusting for covariates using the ANCOVA test, changes in the concentrations of SOD (p = .040), MDA (p = .025), TAC (p=<.001), hs-CRP (p = .017), HbA1c (p = .014), and FBS (p = .027) were statistically significant compared to the placebo group. Intergroup changes in INS were not significant. Additionally, there were no notable side effects during the research.

Conclusions

This study found that NS supplementation significantly enhanced the levels of SOD, MDA, TAC, hs-CRP, HbA1c, and FBS in diabetic HD patients.

Relative leucocyte telomere length is associated with incident end-stage kidney disease and rapid decline of kidney function in type 2 diabetes: analysis from the Hong Kong Diabetes Register

AIMS/HYPOTHESIS

Few large-scale prospective studies have investigated associations between relative leucocyte telomere length (rLTL) and kidney dysfunction in individuals with type 2 diabetes. We examined relationships between rLTL and incident end-stage kidney disease (ESKD) and the slope of eGFR decline in Chinese individuals with type 2 diabetes.

METHODS

We studied 4085 Chinese individuals with type 2 diabetes observed between 1995 and 2007 in the Hong Kong Diabetes Register with stored baseline DNA and available follow-up data. rLTL was measured using quantitative PCR. ESKD was diagnosed based on the ICD-9 code and eGFR.

RESULTS

In this cohort (mean ± SD age 54.3 ± 12.6 years) followed up for 14.1 ± 5.3 years, 564 individuals developed incident ESKD and had shorter rLTL at baseline (4.2 ± 1.2 vs 4.7 ± 1.2, p < 0.001) than the non-progressors (n = 3521). On Cox regression analysis, each ∆∆Ct decrease in rLTL was associated with an increased risk of incident ESKD (HR 1.21 [95% CI 1.13, 1.30], p < 0.001); the association remained significant after adjusting for baseline age, sex, HbA1c, lipids, renal function and other risk factors (HR 1.11 [95% CI 1.03, 1.19], p = 0.007). Shorter rLTL at baseline was associated with rapid decline in eGFR (>4% per year) during follow-up (unadjusted OR 1.22 [95% CI 1.15, 1.30], p < 0.001; adjusted OR 1.09 [95% CI 1.01, 1.17], p = 0.024).

CONCLUSIONS/INTERPRETATION

rLTL is independently associated with incident ESKD and rapid eGFR loss in individuals with type 2 diabetes. Telomere length may be a useful biomarker for the progression of kidney function and ESKD in type 2 diabetes.

Reactive Oxygen Species and Their Involvement in Red Blood Cell Damage in Chronic Kidney Disease

Reactive oxygen species (ROS) released in cells are signaling molecules but can also modify signaling proteins. Red blood cells perform a major role in maintaining the balance of the redox in the blood. The main cytosolic protein of RBC is hemoglobin (Hb), which accounts for 95-97%. Most other proteins are involved in protecting the blood cell from oxidative stress. Hemoglobin is a major factor in initiating oxidative stress within the erythrocyte. RBCs can also be damaged by exogenous oxidants. Hb autoxidation leads to the generation of a superoxide radical, of which the catalyzed or spontaneous dismutation produces hydrogen peroxide. Both oxidants induce hemichrome formation, heme degradation, and release of free iron which is a catalyst for free radical reactions. To maintain the redox balance, appropriate antioxidants are present in the cytosol, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and peroxiredoxin 2 (PRDX2), as well as low molecular weight antioxidants: glutathione, ascorbic acid, lipoic acid, α-tocopherol, β-carotene, and others. Redox imbalance leads to oxidative stress and may be associated with overproduction of ROS and/or insufficient capacity of the antioxidant system. Oxidative stress performs a key role in CKD as evidenced by the high level of markers associated with oxidative damage to proteins, lipids, and DNA in vivo. In addition to the overproduction of ROS, a reduced antioxidant capacity is observed, associated with a decrease in the activity of SOD, GPx, PRDX2, and low molecular weight antioxidants. In addition, hemodialysis is accompanied by oxidative stress in which low-biocompatibility dialysis membranes activate phagocytic cells, especially neutrophils and monocytes, leading to a respiratory burst. This review shows the production of ROS under normal conditions and CKD and its impact on disease progression. Oxidative damage to red blood cells (RBCs) in CKD and their contribution to cardiovascular disease are also discussed.

Seasonal variations in nutritional status and oxidative stress in patients on hemodialysis: Are they related?

OBJECTIVE

Seasonal variations in body composition and parameters that reflect nutritional status are well established in patients on hemodialysis (HD). However, to our knowledge, no study has assessed the changes in oxidative stress (OS). The aims of this study were to assess seasonal variations in OS, body composition, and other nutritional parameters.

METHODS

Seasonal variations in fat tissue mass (FTM), fat tissue index (FTI), adipose tissue mass (ATM), lean tissue mass (LTM), lean tissue index (LTI), body cell mass (BCM), overhydration (OH) volume, and OS (blood levels of derivatives of reactive oxygen metabolites [d-ROMs], thiobarbituric reactive substances, plasma protein reduced thiol content [THIOLS], and ferric reducing ability of plasma) were assessed in 45 patients on HD, 70 y of age (60.5-76.5 y).

RESULTS

FTM (P < 0.001), FTI (P < 0.001), and ATM (P < 0.001) significantly increased, whereas LTI (P < 0.001), LTM (P < 0.001), BCM (P < 0.001), and OH volume (P = 0.004) significantly decreased over the season. Additionally, significant seasonal variations in the levels of d-ROMs (P = 0.02) and THIOLS (P = 0.02) were found. Levels of d-ROMs were found to be a significant predictor of LTM and BCM (β = -0.57; 95% confidence interval [CI], -1.08 to -0.06; P = 0.03; β = -0.04; 95% CI, -0.075 to -0.006; P = 0.02). Furthermore, hip circumference was found to be the most significant predictor of the level of d-ROMs (β = 2.66; 95% CI; 0.28-5.04; P = 0.03) and waist-to-height ratio (β = 251; 95% CI, 16.6-477.2; P = 0.03) and serum prealbumin levels of THIOLS (β = 263; 95% CI, 6.8-521.1; P = 0.04).

CONCLUSION

These results suggest seasonal variations in OS in patients on HD and a possible interaction between OS and nutritional status in these patients.

Plasma Protein Carbonyls as Biomarkers of Oxidative Stress in Chronic Kidney Disease, Dialysis, and Transplantation

Accumulating evidence indicates that oxidative stress plays a role in the pathophysiology of chronic kidney disease (CKD) and its progression; during renal replacement therapy, oxidative stress-derived oxidative damage also contributes to the development of CKD systemic complications, such as cardiovascular disease, hypertension, atherosclerosis, inflammation, anaemia, and impaired host defence. The main mechanism underlying these events is the retention of uremic toxins, which act as a substrate for oxidative processes and elicit the activation of inflammatory pathways targeting endothelial and immune cells. Due to the growing worldwide spread of CKD, there is an overwhelming need to find oxidative damage biomarkers that are easy to measure in biological fluids of subjects with CKD and patients undergoing renal replacement therapy (haemodialysis, peritoneal dialysis, and kidney transplantation), in order to overcome limitations of invasive monitoring of CKD progression. Several studies investigated biomarkers of protein oxidative damage in CKD, including plasma protein carbonyls (PCO), the most frequently used biomarker of protein damage. This review provides an up-to-date overview on advances concerning the correlation between plasma protein carbonylation in CKD progression (from stage 1 to stage 5) and the possibility that haemodialysis, peritoneal dialysis, and kidney transplantation improve plasma PCO levels. Despite the fact that the role of plasma PCO in CKD is often underestimated in clinical practice, emerging evidence highlights that plasma PCO can serve as good biomarkers of oxidative stress in CKD and substitutive therapies. Whether plasma PCO levels merely serve as biomarkers of CKD-related oxidative stress or whether they are associated with the pathogenesis of CKD complications deserves further evaluation.

Oxidative stress accelerates the carotid atherosclerosis process in patients with chronic kidney disease

INTRODUCTION

The atherosclerosis process is highly accelerated in patients with chronic kidney disease (CKD). Oxidative stress is considered as one of the pro-atherogenic factors involved in accelerating the atherosclerosis process of the carotid artery. The aim of the present study was to determine the relationship between oxidative stress markers and the progression of carotid atherosclerosis in CKD patients.

MATERIAL AND METHODS

The study was conducted on 162 patients with CKD and 40 controls, and the disease stage was scored between 2 and 5D. Blood samples were taken and advanced oxidative protein product, myeloperoxidases, malondialdehyde, nitric oxide, glutathione, and oxidised low-density lipoprotein were measured. Furthermore, we studied the correlations between these biomarkers and clinical and para-clinical cardiovascular complications.

RESULTS

The average age of patients was 56.5 years. The oxidative stress markers average ± SD levels in CKD groups compared to the control were as follows: advanced oxidation protein product (61.89 ±1.4 vs. 26.65 ±1.05 µmol/l), myeloperoxidase (59.89 ±1.98 vs. 38.45 ±1.98 UI/ml), malondialdehyde (6.1 ±0.12 vs. 3.26 ±0.03 µmol/l), nitric oxide (65.82 ±1.06 vs. 52.19 ±2.1 µmol/l), glutathione (52.21 ±1.3 vs. 89.4 ±2.6 IU/ml), and oxLDL (15.57 ±1.07 vs. 1.72 ±0.82 µmol/l). While the glutathione level decreased significantly in advanced CKD stage (p < 0.05), the concentrations of all the other biomarkers increased significantly in accordance with CKD score (p < 0.05).

CONCLUSIONS

Cardiovascular diseases, mainly atherosclerosis, can be diagnosed indirectly by measuring oxidative stress markers. Furthermore, theses markers can be used to predict the progression of CKD, for better management of the disease.

Prognostic Value of Inflammation Parameters in Patients With Non-ST Elevation Acute Coronary Syndromes

Inflammation parameters can predict the severity of coronary artery disease and predict long-term mortality. However, there is no study in which these parameters were evaluated together. We compared the prognostic values of inflammation parameters in predicting long-term mortality in patients with non-ST elevation acute coronary syndrome (NSTE-ACS). Consecutive patients with NSTE-ACS (n = 170) were included in the study. Monocyte/high-density lipoprotein cholesterol (HDL-C) ratio (MHR), lymphocyte/monocyte ratio (LMR), neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), total cholesterol/HDL-C ratio (TC/HDL-C), triglyceride /HDL-C ratio (TG/HDL-C), total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index, and ischemia-modified albumin (IMA) were measured. Total antioxidant status and TOS variables were significant independent predictors of mortality. When 1.17 value is taken as a cutoff point of TAS values, the sensitivity (70.0%) and specificity (77.39%) values calculated for this value indicate that TAS variable has a predictive value on mortality. Monocyte/high-density lipoprotein cholesterol ratio, LMR, NLR, PLR, TC/HDL-C, TG/HDL-C, TOS, and IMA levels could not be used alone in the diagnosis, severity assessment, and predicting future mortality of NSTE-ACS. Only TAS levels had a predictive value on mortality.

Prediction of Serum Creatinine in Hemodialysis Patients Using a Kernel Approach for Longitudinal Data

Objectives

Longitudinal data are prevalent in clinical research; due to their correlated nature, special analysis must be used for this type of data. Creatinine is an important marker in predicting end-stage renal disease, and it is recorded longitudinally. This study compared the prediction performance of linear regression (LR), linear mixed-effects model (LMM), least-squares support vector regression (LS-SVR), and mixed-effects least-squares support vector regression (MLS-SVR) methods to predict serum creatinine as a longitudinal outcome.

Methods

We used a longitudinal dataset of hemodialysis patients in Hamadan city between 2013 and 2016. To evaluate the performance of the methods in serum creatinine prediction, the data was divided into two sets of training and testing samples. Then LR, LMM, LS-SVR, and MLS-SVR were fitted. The prediction performance was assessed and compared in terms of mean squared error (MSE), mean absolute error (MAE), mean absolute prediction error (MAPE), and determination coefficient (R²). Variable importance was calculated using the best model to select the most important predictors.

Results

The MLS-SVR outperformed the other methods in terms of the least prediction error; MSE = 1.280, MAE = 0.833, and MAPE = 0.129 for the training set and MSE = 3.275, MAE = 1.319, and MAPE = 0.159 for the testing set. Also, the MLS-SVR had the highest R², 0.805 and 0.654 for both the training and testing samples, respectively. Blood urea nitrogen was the most important factor in the prediction of creatinine.

Conclusions

The MLS-SVR achieved the best serum creatinine prediction performance in comparison to LR, LMM, and LS-SVR.

Chronic Inflammation in Peritoneal Dialysis: The Search for the Holy Grail?

Mortality and morbidity in chronic kidney disease (CKD) patients are unacceptably high. The annual mortality rate due to cardiovascular disease (CVD) is approximately 9%, which, for the middle-aged person, is at least 10- to 20-fold higher than for the general population. Classic risk factors for CVD are highly prevalent in CKD patients, but they cannot fully account for the excessive rate of CVD in this population. Instead, it has become increasingly clear that nontraditional risk factors, such as systemic inflammation, may play a key role in the development of atherosclerosis. It is well established that inflammatory markers are very powerful predictors of high CVD morbidity and mortality not only in the general population, but particularly in CKD patients. Signs of a sustained low-grade inflammation, such as increased levels of C-reactive protein (CRP), are present in the majority of stage 5 CKD patients, even in patients in clinically stable condition, and they are also commonly observed after the initiation of dialysis therapy. Dialysis therapy — hemodialysis as well as peritoneal dialysis (PD) — may itself contribute to systemic inflammation. Local intraperitoneal inflammation can also occur in patients treated with PD. These local effects may result in a low-grade inflammation, caused by the bioincompatibility of conventional glucose-based dialysis fluids, to intense inflammation associated with peritonitis. Given these circumstances, it is reasonable to hypothesize that strategies aiming to reduce inflammation are potentially important and novel, and could serve to reduce CVD, thereby lowering morbidity and mortality in patients with CKD. In this review we provide information supporting the hypothesis that systemic inflammation is tightly linked to the most common complications of CKD patients, in particular those on PD, and that local inflammation in PD may contribute to various related complications. The aims of this review are to discuss the reasons that make inflammation an attractive target for intervention in CKD, the particular aspects of the inflammation–CVD axis during PD treatment that are likely involved, and possible means for the detection and management of chronic inflammation in PD patients.

Significance of 5-S-Cysteinyldopa as a Marker for Melanoma

Melanoma is one of the most lethal and malignant cancers and its incidence is increasing worldwide, and Japan is not an exception. Although there are numerous therapeutic options for melanoma, the prognosis is still poor once it has metastasized. The main concern after removal of a primary melanoma is whether it has metastasized, and early detection of metastatic melanoma would be effective in improving the prognosis of patients. Thus, it is very important to identify reliable methods to detect metastases as early as possible. Although many prognostic biomarkers (mainly for metastases) of melanoma have been reported, there are very few effective for an early diagnosis. Serum and urinary biomarkers for melanoma diagnosis have especially received great interest because of the relative ease of sample collection and handling. Several serum and urinary biomarkers appear to have significant potential both as prognostic indicators and as targets for future therapeutic methods, but still there are no efficient serum and urinary biomarkers for early detection, accurate diagnosis and prognosis, efficient monitoring of the disease and reliable prediction of survival and recurrence. Levels of 5-S-cysteinyldopa (5SCD) in the serum or urine as biomarkers of melanoma have been found to be significantly elevated earlier and to reflect melanoma progression better than physical examinations, laboratory tests and imaging techniques, such as scintigraphy and echography. With recent developments in the treatment of melanoma, studies reporting combinations of 5SCD levels and new applications for the treatment of melanoma are gradually increasing. This review summarizes the usefulness of 5SCD, the most widely used and well-known melanoma marker in the serum and urine, compares 5SCD and other useful markers, and finally its application to other fields.

Interleukin 18 as a new inflammatory mediator in left ventricular hypertrophy in children with end-stage renal disease

Left ventricular hypertrophy (LVH) represents an important determinant of increased cardiovascular morbidity and mortality (CV) in end-stage renal disease (ESRD) patients. The role of inflammatory markers in pathogenesis of LVH in children with ESRD is not fully described. The aim of this study is to evaluate relation of some inflammatory markers [as hs C-reactive protein (hsCRP) and interleukin (IL) 18] with LVH in children with ESRD on regular hemodialysis (HD). This is a cross-sectional study performed on 50 children on regular HD. Demographic data were recorded. Echocardiography was performed at baseline to determine those with LVH. Biochemical parameters: hemoglobin (HB), hsCRP, IL 18, phosphorus, calcium, serum albumin, and lipid profile were evaluated and correlated with LVH. Data were analyzed using Student's t-test, and logistic regression to determine the relationship between LVH and other variables. LVH was present in 33 (66%) participants. Mean left ventricular mass index was 56.88 ± 22.23 g/m.^2.7 Concentric remodeling, concentric hypertrophy, and eccentric hypertrophy were present in 4%, 22%, and 44% of the participants. In univariate analysis, children with LVH had significantly lower levels of HB and serum albumin but higher levels of hsCRP, and IL 18 compared to those without LVH. On multivariate analysis: only hsCRP, and IL 18 were significantly associated with LVH. This study shows that elevated hsCRP and IL-18 are independent determinants of LVH in HD children. Understanding the role of inflammatory molecules in the pathogenesis of LVH in ESRD is important for prediction of high-risk group and implementation of targeted anti-inflammatory therapies.

Evaluation of Electrolyte Concentration and Pro-Inflammatory and Oxidative Status in Dogs with Advanced Chronic Kidney Disease under Dietary Treatment

An integrated study on the effect of renal diet on mineral metabolism, fibroblast growth factor 23 (FGF-23), total antioxidant capacity, and inflammatory markers has not been performed previously. In this study, we evaluated the effects of renal diet on mineral metabolism, oxidative stress and inflammation in dogs with stage 3 or 4 of chronic kidney disease (CKD). Body condition score (BCS), muscle condition score (MCS), serum biochemical profile, ionized calcium (i-Ca), total calcium (t-Ca), phosphorus (P), urea, creatinine, parathyroid hormone (PTH), FGF-23, interleukin 6 (IL-6), interleukin 10 (IL-10), tumor necrosis factor alpha (TNF-α) and total antioxidant capacity (TAC) were measured at baseline (T0) and after 6 months of dietary treatment (T6). Serum urea, P, t-Ca, i-Ca, PTH, FGF-23, IL-6, IL-10, TNF-α and TAC measurements did not differ between T0 and T6. Serum creatinine (SCr) was increased at T6 and serum PTH concentrations were positively correlated with serum SCr and urea. i-Ca was negatively correlated with urea and serum phosphorus was positively correlated with FGF-23. Urea and creatinine were positively correlated. The combination of renal diet and support treatment over 6 months in dogs with CKD stage 3 or 4 was effective in controlling uremia, acid–base balance, blood pressure, total antioxidant capacity, and inflammatory cytokine levels and in maintaining BCS and MCS.

Oxidative Stress in Hemodialysis Pediatric Patients

BACKGROUND:

Oxidative stress may play a role in complications of hemodialysis patients as atherosclerosis, thrombosis, and inflammation.

AIM:

The aim of the study was to evaluate the oxidative stress in hemodialysis pediatric patients through measurement of oxidative stress enzymes as paraoxanase activity (PON), arylesterase activity (ASA), superoxide dismutase (SOD) and also non-enzymatic antioxidant vitamins as vitamins A, C and E levels.

METHODS:

The study included 50 hemodialysis pediatric patients with mean age 11.4 ± 5.4 years and 30 normal children of matched sex and age as a control group. Assessment of oxidative stresses was done using ELIZA technique.

RESULTS:

SOD, ASA, and vitamin C were significantly lower among hemodialysis patients in comparison to control group (p = 0.004, 0.004, > 0.001 respectively).

CONCLUSION:

The study concluded that oxidative stress was common finding in hemodialysis pediatric patients which may play a role in complications encountered among these patients.

Oxidative Imbalance and Kidney Damage: New Study Perspectives from Animal Models to Hospitalized Patients

Chronic kidney disease (CKD) is a major public health problem worldwide and affects both elderly and young subjects. Its main consequences include the loss of renal function, leading to end-stage renal disease, an increased risk of cardiovascular disease, a significant increase in morbidity and mortality, and a decrease in health-related quality of life. This review arose in significant part from work in the authors' laboratory, complemented by literature data, and was based on a translational approach: we studied the role of many CKD risk factors, such as hypertension, obesity, and oxidative stress/inflammation. The aim was to identify new molecular mechanisms of kidney damage to prevent it through successful behavior modifications. For this purpose, in our studies, both human and animal models were used. In the animal models, we analyzed the mechanisms of renal damage induced by hypertension (spontaneously hypertensive rats) and obesity (cafeteria diet-fed rats), showing that redox disequilibrium in plasma and tissue is extremely important in renal alteration in terms of both oxidative damage (lipid peroxidation, altered expression antioxidant enzymes) and apoptotic pathway (intrinsic/extrinsic) activation. In hemodialysis patients, we explored the correlation between the global oxidative balance and both inflammatory markers and cardiovascular risk, showing a strong correlation between the oxidative index and the blood levels of C-reactive protein and previous cardiovascular events. This multilevel approach allowed us to individually and synergistically analyze some aspects of the complex pathogenic mechanisms of CKD in order to clarify the role of the new amplified risk factors for CKD and to prepare an effective personalized prevention plan by acting on both modifiable and nonmodifiable risk factors.

Oxidative Status before and after Renal Replacement Therapy: Differences between Conventional High Flux Hemodialysis and on-Line Hemodiafiltration

Hemodialysis patients experience high oxidative stress because of systemic inflammation and depletion of antioxidants. Little is known about the global oxidative status during dialysis or whether it is linked to the type of dialysis. We investigated the oxidative status before (pre-) and after (post-) one dialysis session in patients subjected to high-flux dialysis (HFD) or on-line hemodiafiltration (OL-HDF). We analyzed carbonyls, oxidized LDL (oxLDL), 8-hydroxy-2′-deoxyguanosine, and xanthine oxidase (XOD) activity as oxidative markers, and total antioxidant capacity (TAC), catalase, and superoxide dismutase activities as measures of antioxidant defense. Indices of oxidative damage (OxyScore) and antioxidant defense (AntioxyScore) were computed and combined into a global DialysisOxyScore. Both dialysis modalities cleared all markers (p < 0.01) except carbonyls, which were unchanged, and oxLDL, which increased post-dialysis (p < 0.01). OxyScore increased post-dialysis (p < 0.001), whereas AntioxyScore decreased (p < 0.001). XOD and catalase activities decreased post-dialysis after OL-HDF (p < 0.01), and catalase activity was higher after OL-HDF than after HFD (p < 0.05). TAC decreased in both dialysis modalities (p < 0.01), but remained higher in OL-HDF than in HFD post-dialysis (p < 0.05), resulting in a lower overall DialysisOxyScore (p < 0.05). Thus, patients on OL-HDF maintain higher levels of antioxidant defense, which might balance the elevated oxidative stress during dialysis, although further longitudinal studies are needed.

Arterial "inflammaging" drives vascular calcification in children on dialysis

Children on dialysis have a cardiovascular mortality risk equivalent to older adults in the general population, and rapidly develop medial vascular calcification, an age-associated pathology. We hypothesized that premature vascular ageing contributes to calcification in children with advanced chronic kidney disease (CKD). Vessels from children with Stage 5 CKD with and without dialysis had evidence of increased oxidative DNA damage. The senescence markers p16 and p21 were also increased in vessels from children on dialysis. Treatment of vessel rings ex vivo with calcifying media increased oxidative DNA damage in vessels from children with Stage 5 CKD, but not in those from healthy controls. Vascular smooth muscle cells cultured from children on dialysis exhibited persistent DNA damage, impaired DNA damage repair, and accelerated senescence. Under calcifying conditions vascular smooth muscle cells from children on dialysis showed increased osteogenic differentiation and calcification. These changes correlated with activation of the senescence-associated secretory phenotype (SASP), an inflammatory phenotype characterized by the secretion of proinflammatory cytokines and growth factors. Blockade of ataxia-telangiectasia mutated (ATM)-mediated DNA damage signaling reduced both inflammation and calcification. Clinically, children on dialysis had elevated circulating levels of osteogenic SASP factors that correlated with increased vascular stiffness and coronary artery calcification. These data imply that dysregulated mineral metabolism drives vascular "inflammaging" by promoting oxidative DNA damage, premature senescence, and activation of a pro-inflammatory SASP. Drugs that target DNA damage signaling or eliminate senescent cells may have the potential to prevent vascular calcification in patients with advanced CKD.

Oxidative Balance and Inflammation in Hemodialysis Patients: Biomarkers of Cardiovascular Risk?

During chronic kidney disease, the progressive deterioration of renal function induces several biological/clinical dysfunctions, including enhancement of synthesis of inflammation/oxidative stress mediators. Impaired renal function is an independent cardiovascular risk factor; indeed, cardiovascular complications dominate the landscape of both chronic kidney disease and end-stage renal disease. The aim of this study is to explore the correlation between the global oxidative balance in hemodialysis patients and both inflammatory markers and cardiovascular events. Using photometric tests, this study explored plasmatic oxidative balance in 97 hemodialysis patients compared to a healthy population. In the hemodialysis patients, we showed that oxidative stress values were significantly lower than in controls while effectiveness in the antioxidant barrier was significantly increased in the hemodialysis group. Furthermore, we highlighted a strong correlation between oxidative index and blood levels of C-reactive protein. When patients were divided into two groups based on previous cardiovascular events, we found that subjects with previous cardiovascular events had higher values of both oxidative stress and antioxidant barrier than patients without cardiovascular events. Our results indicated that in hemodialysis patients, the clinical and prognostic significance of oxidative status is very different from general population. As cardiovascular complications represent a strong negative factor for survival of hemodialysis patients, the research of new cardiovascular risk biomarkers in these patients takes on particular importance in order to translate them into clinical practice/primary care.

Application of liquisolid technology for promoting the renoprotective efficacy of walnut extracts in chronic renal failure rat model

Chronic renal failure (CRF) is among the major health problems that could lead to increased morbidity and mortality among population. 'Nutraceuticals' is an emerging field for natural agents from plant foods that could reduce the progression of such disease. Many newly developed drugs are having bioavailability problems owing to their water insolubility. Liquisolid technique is one of the promising technological approaches to increase solubility and hence, drug absorption. The aim of the present research is to prepare and evaluate the renoprotective effect of the walnut extracts liquisolid formulations in CRF rat model. Saturation solubility study claimed PEG 400 and Tween 20 as good solubilizers for walnut extracts, thus chosen for preparation. The angle of slide was determined for the carrier; microcrystalline cellulose and coating material; silicon dioxide and liquid load factor was evaluated. Eight liquisolid systems were prepared employing 25% and 50% of liquid medication. Their flow and compressibility parameters showed good properties. Dissolution study was more in favor of formulations prepared using PEG 400. Of these, formulation F8 comprising carrier/coat ratio (10:1) and 50% liquid medication, showing superior dissolution properties was selected to perform stability and in-vivo evaluations. Two CRF induced rat groups received F8 at two oral doses (50 and 100 mg/kg). Biochemical and nutritional parameters were compared with both normal and CRF control rats. Results showed improvement of renal function, oxidative stress, antioxidant and inflammatory biomarkers as well as increased appetite and body weight gain on administration of both doses of walnut liquisolid formulation, F8.

Oxidized Low-Density Lipoprotein Serum Concentrations and Cardiovascular Morbidity in End Stage of Renal Disease

Introduction: Oxidized low-density lipoprotein (ox-LDL) is considered a main biomarker of oxidative stress, a common characteristic in end stage renal disease. We examined the relationship between ox-LDL serum concentrations and cardiovascular disease in permanent hemodiafiltration therapy patients. Methods: Ox-LDL values were measured by ELISA and were corrected for LDL-cholesterol (LDL-C) in 96 participants and in 45 healthy control subjects. We performed chi-square tests and adjusted models for the role of ox-LDL on cardiovascular morbidity including coronary artery disease, left ventricular hypertrophy, systolic, diastolic dysfunction and peripheral arterial disease. Results: ox-LDL/LDL-C values were significantly higher in patients than in control group (p = 0.02), due to increased ox-LDL serum levels rather than to low LDL-C. The unadjusted relationship between high ox-LDL/LDL-C and low ejection fraction was found significant (x2 = 9.04, p = 0.003), although the association with the other cardiovascular manifestations was found non-significant. In the adjusted model for the prediction of systolic cardiac dysfunction, high ox-LDL/LDL-C, old age and non-administration of vitamin D supplementation during dialysis session were found to be significant predictors after adjustment to the confounder. Moreover, the association between systolic cardiac dysfunction and non-administration of vitamin D derivatives during dialysis sessions was found significant (x2 = 6.9, p = 0.008). Conclusions: This study showed a significant association between high ox-LDL and systolic cardiac dysfunction in permanent hemodiafiltration therapy patients. This relationship seems to be influenced by aging and pharmaceutical therapy during dialysis sessions, including vitamin D derivatives.

Oxidized Low-Density Lipoprotein Serum Concentrations and Cardiovascular Morbidity in End Stage of Renal Disease

INTRODUCTION

Oxidized low-density lipoprotein (ox-LDL) is considered a main biomarker of oxidative stress, a common characteristic in end stage renal disease. We examined the relationship between ox-LDL serum concentrations and cardiovascular disease in permanent hemodiafiltration therapy patients.

METHODS

Ox-LDL values were measured by ELISA and were corrected for LDL-cholesterol (LDL-C) in 96 participants and in 45 healthy control subjects. We performed chi-square tests and adjusted models for the role of ox-LDL on cardiovascular morbidity including coronary artery disease, left ventricular hypertrophy, systolic, diastolic dysfunction and peripheral arterial disease.

RESULTS

ox-LDL/LDL-C values were significantly higher in patients than in control group (p = 0.02), due to increased ox-LDL serum levels rather than to low LDL-C. The unadjusted relationship between high ox-LDL/LDL-C and low ejection fraction was found significant (x² = 9.04, p = 0.003), although the association with the other cardiovascular manifestations was found non-significant. In the adjusted model for the prediction of systolic cardiac dysfunction, high ox-LDL/LDL-C, old age and non-administration of vitamin D supplementation during dialysis session were found to be significant predictors after adjustment to the confounder. Moreover, the association between systolic cardiac dysfunction and non-administration of vitamin D derivatives during dialysis sessions was found significant (x² = 6.9, p = 0.008).

CONCLUSIONS

This study showed a significant association between high ox-LDL and systolic cardiac dysfunction in permanent hemodiafiltration therapy patients. This relationship seems to be influenced by aging and pharmaceutical therapy during dialysis sessions, including vitamin D derivatives.

Elevated Neutrophil Gelatinase Lipocalin Levels Are Associated With Increased Oxidative Stress in Hemodialysis Patients

BACKGROUND

Administration of intravenous iron is an essential treatment of anemia in hemodialysis patients, but it may lead to oxidative stress and increased morbidity and mortality. There is evidence that neutrophil gelatinase-associated lipocalin (NGAL) is protective against oxidative stress and thus the aim of the present study was to investigate the relationship between plasma NGAL and advanced oxidative protein products (AOPP) in hemodialysis patients treated with intravenous iron.

METHODS

In a prospective study, 47 hemodialysis patients (mean age 63 years, SD = 13.6; 40% women) were enrolled from two separate hospitals. Oxidative stress was induced by an intravenous administration of 100 mg iron saccharate 0.5 h after the start of dialysis. Blood samples were drawn at the beginning of the dialysis, 0.5 h after iron administration and at the end of dialysis. NGAL levels were measured from the first blood sample, AOPP levels were measured from all blood samples.

RESULTS

Our results showed that higher NGAL and AOPP levels at the beginning of the dialysis, prior to iron administration, significantly predicted higher levels of AOPP toward the end of dialysis, (β = 0.355, SE = 0.054, P = 0.035; β = 0.297, SE = 0.159, P = 0.043, respectively).

CONCLUSIONS

Our results suggest that higher level of NGAL is a risk factor for oxidative stress, as measured by AOPP levels, in dialysis patients receiving intravenous iron. Our findings could identify dialysis patients who are at higher risk from iron supplementation via measurement of NGAL levels.

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

BACKGROUND

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

PATIENT AND METHODS

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

RESULTS

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

CONCLUSION

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

Impact of blood urea nitrogen to creatinine ratio on mortality and morbidity in hemodialysis patients: The Q-Cohort Study

The association between blood urea nitrogen to creatinine ratio (UCR) and survival is uncertain in hemodialysis patients. We examined the influence of UCR on mortality and morbidity in hemodialysis patients. A total of 3,401 hemodialysis patients were prospectively followed for 4 years. The association between UCR with overall survival was analyzed using a Cox regression model. During a 4-year follow-up period, 545 patients died from any cause and 582 experienced MACE, 392 with coronary heart disease (CHD), 114 with infection-related death, 77 with hemorrhagic stroke, 141 with ischemic stroke, and 107 with cancer death. Every 1 increase in UCR level was significantly associated with an increased risk for all-cause mortality (hazard ratio [HR] 1.07; 95% confidence interval [CI] 1.03–1.12), CHD (HR 1.08; 95% CI 1.02–1.14), and infection-related death (HR 1.11; 95% CI 1.02–1.21). There was no evidence of a significant association between UCR and death from cancer, and incidence of stroke. A high UCR was significantly associated with an increased risk for all-cause mortality, infection-related death and incidence of CHD in hemodialysis patients.

Oxidative Stress in Hemodialysis Patients: A Review of the Literature

Hemodialysis (HD) patients are at high risk for all-cause mortality and cardiovascular events. In addition to traditional risk factors, excessive oxidative stress (OS) and chronic inflammation emerge as novel and major contributors to accelerated atherosclerosis and elevated mortality. OS is defined as the imbalance between antioxidant defense mechanisms and oxidant products, the latter overwhelming the former. OS appears in early stages of chronic kidney disease (CKD), advances along with worsening of renal failure, and is further exacerbated by the HD process per se. HD patients manifest excessive OS status due to retention of a plethora of toxins, subsidized under uremia, nutrition lacking antioxidants and turn-over of antioxidants, loss of antioxidants during renal replacement therapy, and leukocyte activation that leads to accumulation of oxidative products. Duration of dialysis therapy, iron infusion, anemia, presence of central venous catheter, and bioincompatible dialyzers are several factors triggering the development of OS. Antioxidant supplementation may take an overall protective role, even at early stages of CKD, to halt the deterioration of kidney function and antagonize systemic inflammation. Unfortunately, clinical studies have not yielded unequivocal positive outcomes when antioxidants have been administered to hemodialysis patients, likely due to their heterogeneous clinical conditions and underlying risk profile.

Naturally Occurring Compounds: New Potential Weapons against Oxidative Stress in Chronic Kidney Disease

Oxidative stress is a well-described imbalance between the production of reactive oxygen species (ROS) and the antioxidant defense system of cells and tissues. The overproduction of free radicals damages all components of the cell (proteins, lipids, nucleic acids) and modifies their physiological functions. As widely described, this condition is a biochemical hallmark of chronic kidney disease (CKD) and may dramatically influence the progression of renal impairment and the onset/development of major systemic comorbidities including cardiovascular diseases. This state is exacerbated by exposure of the body to uremic toxins and dialysis, a treatment that, although necessary to ensure patients' survival, exposes cells to non-physiological contact with extracorporeal circuits and membranes with consequent mitochondrial and anti-redox cellular system alterations. Therefore, it is undeniable that counteracting oxidative stress machinery is a major pharmacological target in medicine/nephrology. As a consequence, in recent years several new naturally occurring compounds, administered alone or integrated with classical therapies and an appropriate lifestyle, have been proposed as therapeutic tools for CKD patients. In this paper, we reviewed the recent literature regarding the "pioneering" in vivo testing of these agents and their inclusion in small clinical trials performed in patients affected by CKD.

C-reactive protein variability is associated with vascular access outcome in hemodialysis patients

BACKGROUND

Hemodialysis (HD) vascular access failure is one of the most important causes of morbidity and contributes to the cost of dialysis care. There is paucity of data evaluating long-term monitoring of C-reactive protein (CRP) on outcome of HD vascular access.

METHODS

We conducted a retrospective study to investigate whether variability of serum CRP level was associated with vascular access failure rate over a 7-year period. A total of 318 HD patients were included. Their demographic data, co-morbidities and biochemical data were reviewed and collected. Serum high-sensitivity CRP (hs-CRP) level was measured every 6 months. Patients were divided into three groups according to their serial hs-CRP levels. Patients with their hs-CRP below 2 mg/L were defined as low group (n=65, 20.4%) and those with higher than 4 mg/L were defined as high (n=39, 12.3%). The rest were classified as fluctuated hs-CRP group (n=214, 67.3%). Treatment of vascular access failure includes angioplasty and access re-creation.

RESULTS

Their body mass index, indicators of dialysis adequacy and serum albumin and hs-CRP levels differed significantly among three groups. The annual vascular access failure rate was significantly higher in fluctuated hs-CRP group than in high hs-CRP group (0.41 vs 0.36, P=.037). Serum albumin was a significant associate of vascular access failure. Kaplan-Meier survival analysis indicated patients with high or fluctuated hs-CRP had shorter free interval of vascular access failure than low hs-CRP group.

CONCLUSIONS

HD patients with fluctuated hs-CRP levels were associated with increased vascular access failure.

Oxidative stress and cardiac dysfunction in children with chronic renal failure on regular hemodialysis

OBJECTIVE

The objective of this study was to evaluate cardiac function in children with end-stage renal disease (ESRD) on regular hemodialysis using speckle tracking echocardiography (STE) and correlate results with plasma glutathione level as a marker of oxidative stress.

METHODS

The study involved 30 children with ESRD and 30 healthy controls. The plasma glutathione and C-reactive protein (CRP) levels were measured, and cardiac function was evaluated using conventional echocardiography and STE.

RESULTS

Plasma glutathione levels were significantly lower and CRP significantly higher in patients than in controls. Children with ESRD had significant systolic and diastolic cardiac dysfunctions detected by STE compared with controls. Conventional echocardiography failed to detect these dysfunctions. There was significant increase in left-ventricular relative wall thickness (LV-RWT) in patients, especially those with hypertension, compared with the control group. There was also significant impairment of LV and right-ventricular (RV) global longitudinal strain (GLS) and torsion; however, LV-GLS was significantly better in hypertensive than in normotensive patients. The degree of impairment in GLS and cardiac torsion negatively correlated with plasma glutathione levels.

CONCLUSION

Significant oxidative stress was present in children with ESRD and was correlated with the degree of cardiac dysfunction detected early using the new cardiac imaging modality, STE.

Red blood cell abnormalities and the pathogenesis of anemia in end-stage renal disease

Anemia is the most common hematologic complication in end-stage renal disease (ESRD). It is ascribed to decreased erythropoietin production, shortened red blood cell (RBC) lifespan, and inflammation. Uremic toxins severely affect RBC lifespan; however, the implicated molecular pathways are poorly understood. Moreover, current management of anemia in ESRD is controversial due to the "anemia paradox" phenomenon, which underlines the need for a more individualized approach to therapy. RBCs imprint the adverse effects of uremic, inflammatory, and oxidative stresses in a context of structural and functional deterioration that is associated with RBC removal signaling and morbidity risk. RBCs circulate in hostile plasma by raising elegant homeostatic defenses. Variability in primary defect, co-morbidity, and therapeutic approaches add complexity to the pathophysiological background of the anemic ESRD patient. Several blood components have been suggested as biomarkers of anemia-related morbidity and mortality risk in ESRD. However, a holistic view of blood cell and plasma modifications through integrated omics approaches and high-throughput studies might assist the development of new diagnostic tests and therapies that will target the underlying pathophysiologic processes of ESRD anemia.

Disturbances in Bone Largely Predict Aortic Calcification in an Alternative Rat Model Developed to Study Both Vascular and Bone Pathology in Chronic Kidney Disease

Because current rat models used to study chronic kidney disease (CKD)-related vascular calcification show consistent but excessive vascular calcification and chaotic, immeasurable, bone mineralization due to excessive bone turnover, they are not suited to study the bone-vascular axis in one and the same animal. Because vascular calcification and bone mineralization are closely related to each other, an animal model in which both pathologies can be studied concomitantly is highly needed. CKD-related vascular calcification in rats was induced by a 0.25% adenine/low vitamin K diet. To follow vascular calcification and bone pathology over time, rats were killed at weeks 4, 8, 10, 11, and 12. Both static and dynamic bone parameters were measured. Vascular calcification was quantified by histomorphometry and measurement of the arterial calcium content. Stable, severe CKD was induced along with hyperphosphatemia, hypocalcemia as well as increased serum PTH and FGF23. Calcification in the aorta and peripheral arteries was present from week 8 of CKD onward. Four and 8 weeks after CKD, static and dynamic bone parameters were measurable in all animals, thereby presenting typical features of hyperparathyroid bone disease. Multiple regression analysis showed that the eroded perimeter and mineral apposition rate in the bone were strong predictors for aortic calcification. This rat model presents a stable CKD, moderate vascular calcification, and quantifiable bone pathology after 8 weeks of CKD and is the first model that lends itself to study these main complications simultaneously in CKD in mechanistic and intervention studies.

Mitochondria: a new therapeutic target in chronic kidney disease

Cellular metabolic changes during chronic kidney disease (CKD) may induce higher production of oxygen radicals that play a significant role in the progression of renal damage and in the onset of important comorbidities. This condition seems to be in part related to dysfunctional mitochondria that cause an increased electron "leakage" from the respiratory chain during oxidative phosphorylation with a consequent generation of reactive oxygen species (ROS). ROS are highly active molecules that may oxidize proteins, lipids and nucleic acids with a consequent damage of cells and tissues. To mitigate this mitochondria-related functional impairment, a variety of agents (including endogenous and food derived antioxidants, natural plants extracts, mitochondria-targeted molecules) combined with conventional therapies could be employed. However, although the anti-oxidant properties of these substances are well known, their use in clinical practice has been only partially investigated. Additionally, for their correct utilization is extremely important to understand their effects, to identify the correct target of intervention and to minimize adverse effects. Therefore, in this manuscript, we reviewed the characteristics of the available mitochondria-targeted anti-oxidant compounds that could be employed routinely in our nephrology, internal medicine and renal transplant centers. Nevertheless, large clinical trials are needed to provide more definitive information about their use and to assess their overall efficacy or toxicity.

The bacterial colonization in tunneled cuffed dialysis catheter and its effects on residual renal function in incident hemodialysis patients

BACKGROUND

The bacterial colonization of hemodialysis catheter occurs frequently and reaches to the catheter-related bloodstream infections (CRBSIs). We hypothesized bacterial colonization promotes inflammation and that might be associated with renal outcome. The aim of this study was to investigate the colonization status for tunneled cuffed dialysis catheter (TCC) and the factors for contributing to the catheter colonization and explore whether bacterial colonization would be related with declining of residual renal function (RRF).

METHODS

115 patients who received TCC removal operation and underwent catheter tip culture from January 2005 to June 2014 were enrolled. The follow-up data such as urine output (UO), time to anuria and patients' survival were collected from the patients or their family members by telephone in June, 2014.

RESULTS

There were nineteen patients (16.5 %, 19/115) with positive tip culture (colonization group). In the analysis of demographic and biochemical parameters, there were no significant differences between both groups. Fifty of all the subjects responded to the telephone survey and ten patients (20.0 %, 10/50) belonged to colonization group. The monthly decreasing rate of UO was significantly more rapid in colonization group (p = 0.001). The survival analysis showed that colonization group had worse estimated anuria-free survival than non-colonization group (p < 0.001). In multivariate cox regression, bacterial colonization of TCC was an independent factor influencing the loss of RRF (HR 4.29, 95 % CI: 1.905-9.683, p ≤ 0.001).

CONCLUSIONS

Bacterial colonization of TCC was associated with rapid loss of RRF.

New insights in molecular mechanisms involved in chronic kidney disease using high-resolution plasma proteome analysis

BACKGROUND

The reduced glomerular filtration rate in the advanced stages of chronic kidney disease (CKD) leads to plasma accumulation of uraemic retention solutes including proteins. It has been hypothesized that these changes may, at least in part, be responsible for CKD-associated morbidity and mortality. However, most studies focused on the role of individual proteins, while a holistic, large-scale, integrative approach may generate significant additional insight.

METHODS

In a discovery study, we analysed the plasma proteome of patients with stage 2-3 CKD (n = 14) and stage 5 CKD with haemodialysis (HD) (n = 15), using high-resolution LC-MS/MS analysis. Selected results were validated in a cohort of 40 patients with different CKD stages with or without HD, using ELISA.

RESULTS

Of a total of 2054 detected proteins, 127 displayed lower, while 206 displayed higher abundance in the plasma of patients on HD. Molecular pathway analysis confirmed the modification of known processes involved in CKD complications, including decreased haemostasis and increased inflammation, complement activation and vascular damage. In addition, we identified the plasma increase during CKD progression of lysozyme C and leucine-rich alpha-2 glycoprotein, two proteins related to vascular damage and heart failure. High level of leucine-rich alpha-2 glycoprotein was associated with higher mortality in stage 5 CKD patients on HD.

CONCLUSIONS

This study provides for the first time a comprehensive assessment of CKD plasma proteome, contributing to new knowledge and potential markers of CKD. These results will serve as a basis for future studies investigating the relevance of these molecules in CKD associated morbidity and mortality.

Changes in the conformational state of hemoglobin in hemodialysed patients with chronic renal failure

The aim of this study was to evaluate the properties of internal components of erythrocytes in chronic renal failure (CRF) patients undergoing hemodialysis (HD) in comparison to control subjects. For investigation of conformational state of hemoglobin and nonheme proteins (NHP) the maleimide spin label (MSL) in electron paramagnetic resonance (EPR) was applied. The studies were performed using MSL in whole cells and hemolysate as well as proteins separated by ion exchange chromatography and checked by electrophoresis. Additionally the level of –SH groups in hemolysate and isolated internal proteins of CRF erythrocytes was determined using 4,4′-dithiodipyridine. All measurements were performed before and after hemodialysis. Oxidative stress accompanying CRF/hemodialysed patients caused a significant decrease in the mobility of internal components inside erythrocytes indicated by MSL (P < 0.02). The significant decrease in mobility of spin labeled HbA_1c and HbA both before and after HD (P < 0.0002) as well as in nonheme proteins before hemodialysis (P < 0.05) versus control was indicated. Decrease in mobility of internal components of erythrocytes was accompanied by loss of thiols before and after hemodialysis versus control in NHP (P < 0.05), HbA_1c (P < 0.0002), and HbA (P < 0.0005). These findings showed oxidative influence of hemodialysis on hemoglobins and internal nonheme proteins in erythrocytes of CRF patients.

Hemodialysis-associated cardiomyopathy: a newly defined disease entity

Cardiovascular disease is the most common cause of the greatly elevated rates of mortality characteristic of patients undergoing maintenance hemodialysis. This article is an attempt to describe the complex and evolving features of cardiac disease routinely encountered in HD patients. Furthermore, by trying to appreciate the pathophysiological drivers, and the crucial interaction with the HD treatment itself, this article seeks to define cardiac disease in this setting (HD-associated cardiomyopathy) as a unique and complex entity. By understanding the phenotype and basis of HD-associated cardiomyopathy, we can develop an evolved understanding of the dominant processes involved in its development and offer up dialysis-based interventions specifically designed to mitigate the cumulative ischemic insults consequent to conventional HD treatment. This article explores the justification of this approach and recent evidence of its efficacy.