Ebru Gok Oguz

Is hepcidin‐25 a predictor of atherosclerosis in hemodialysis patients?

Atherosclerotic cardiovascular disease is an important cause of mortality and morbidity in hemodialysis patients. Iron accumulation in arterial wall macrophages is increased in atherosclerotic lesions. Hepcidin is a key hepatic hormone regulating iron balance. It inhibits iron release from macrophages and iron absorption from enterocytes by binding and inactivating the cellular iron exporter ferroportin. The aim of this study is to investigate the relation of hepcidin‐25, iron parameters, and atherosclerosis measured by carotid intima media thickness (CIMT) in hemodialysis patients. Eighty‐two hemodialysis patients were enrolled in this cross‐sectional study. Predialysis blood samples were centrifuged at 1500 g and 4°C for 10 minutes and stored at −80°C for the measurement of hepcidin‐25. DRG hepcidin enzyme‐linked immunosorbent assay kit was used for the measurement of hepcidin‐25. Ultrasonographical B‐mode imaging of bilateral carotid arteries was performed with a high‐resolution real‐time ultrasonography (Mindray DC7). Mean age of the study population was 57.90 ± 16.08 years and 43.9% were men. Total study population was grouped into two according to median value of hepcidin‐25. There was no difference between groups with respect to age, dialysis vintage, and C‐reactive protein. CIMT was found to be statistically significantly higher in low hepcidin‐25 group. In correlation analysis, CIMT was found to be correlated with age (P < 0.01, R = 0.33) and hepcidin‐25 (P < 0.01, R = 0.46). In linear regression analysis, age (β = 0.31) and hepcidin‐25 (β = 0.44) were found to be the determinants of CIMT in hemodialysis patients. Our results implicate that hepcidin may take part in pathophysiology of atherosclerosis and cardiovascular disease in hemodialysis patients.

The Effect of Hemodialysis on Cardiac Enzyme Levels and Echocardiographic Parameters

Background Cardiac troponins are specific and sensitive markers of myocardial damage. Troponin levels may increase without an obvious active cardiac disease in hemodialysis patients. In this study, we aimed to investigate the effect of a single hemodialysis session on echocardiographic parameters and cardiac enzyme levels, including cTn-I, creatine phosphokinase (CPK), and creatine kinase-MB (CK-MB). Patients and methods Forty patients under chronic hemodialysis treatment enrolled in this prospective study. All the patients had a physical examination and underwent echocardiography before and after hemodialysis. cTn-I, CPK and CK-MB levels were also determined before and after hemodialysis in all patients. Results Post-dialysis cTn-I levels were significantly higher compared to pre-dialysis levels (p = 0.03). cTn-I levels increased in 26 patients, did not change in 1 patient and decreased in 13 patients after hemodialysis when compared to the values determined before hemodialysis. There was no significant increase in CPK and CK-MB levels after dialysis. Statistically significant changes were detected in the end-systolic diameter of the left ventricle, end-diastolic diameter of left ventricle, ejection fraction, diameter of the left atrium, diameter of the right atrium, pulmonary artery pressure and end-diastolic diameter of the right ventricle. However, there was no significant relation between these echocardiographic changes and ultrafiltration volume, blood flow rate, age, and gender. Conclusions Hemodialysis leads to an increase in cTnI levels. However, the effect of increased cTnI levels on survival rates in hemodialysis patients with underlying coronary artery disease has not yet been determined. Prospective multi-center studies with large sample size are required to clarify this issue.

Community-acquired hypernatremia in elderly and very elderly patients admitted to the hospital: Clinical characteristics and outcomes

Summary Background The clinical features, outcome and cost burden of community-acquired hypernatremia (CAH) in elderly and very elderly patients are not well known. Our aim was to investigate the etiologies, reasons for admission, clinical courses, outcomes, complications, and cost assessments of the elderly patients with CAH. Material/Methods We conducted a retrospective study in our tertiary hospital. Elderly and very elderly patients evaluated in the emergency department (ED) from January 1, 2010 to December 31, 2010 (n=4960) were included. Totally, 102 patients older than 65 years and diagnosed with CAH were evaluated. The patients were divided into 2 main groups according to their age: elderly (65–74 years old) (group 1) (n=38), and very elderly (>74 years) (group 2) (n=64). Results Our overall observed prevalence of CAH was 2.0% (n=102, 102/4960). In particular, the prevalences of CAH in group 1 and group 2 were 1.0% (38/3651) and 4.8% (64/1309), respectively (p<0.001). Totally, 62 patients had been treated by renin-angiotensin system (RAS) blockers (ie, ACE-inhibitors). Alzheimer’s disease had been diagnosed in 46.1% of the subjects. The mean Katz scores at the time of admission were 2.4±1.9 and 1.1±1.0 in group 1 and 2, respectively (p<0.001). The mean cost was higher in group 2 than in group 1 (2407.13±734.54 USD, and 2141.12±1387.14 USD, respectively) (p<0.01). The need for intensive care was significantly greater in group 2 as compared to group 1. Conclusions The important determinants of “CAH” in elderly subjects are accompanying Alzheimer’s disease, oral intake impairment, and concomitant treatment with RAS blockers.

Lack of nephrotoxicity of gadopentetate dimeglumine-enhanced non-vascular MRI and MRI without contrast agent in patients at high-risk for acute kidney injury.

Background Gadolinium chelates (GCs) have been traditionally considered as non-nephrotoxic magnetic resonance imaging (MRI) contrast materials. However, it has been suggested in some recent articles that GCs may have a nephrotoxic potential, but most of these reports are retrospective. However, the evaluated contrast agents, their doses, and the tests used to determine the kidney function were not consistent across studies. We aimed to investigate the effect of magnetic field and an MRI contrast agent, gadopentetate dimeglumine (GD), on renal functions in patients at high risk for acute kidney injury (AKI). Material/Methods We designed a prospective case-control study with 2 age- and sex-matched groups of patients at high-risk for AKI (n=72 for each group). Patients in Group 1 received a fixed dose of (0.2 mmol/kg) GD-enhanced non-vascular MRI and patients in Group 2 received MRI without GD. Before the MRI and at 6, 24, 72, and 168 hours after the MRI, biochemical tests, estimated glomerular filtration rate (eGFR), albumin/creatinine ratio in spot urine, and early AKI biomarkers (cystatin C, N-Acetyl-Glucosaminidase [NAG], Neutrophil gelatinase-associated lipocalin [NGAL]) were measured. Results Serum creatinine, albumin/creatinine ratio, and eGFR were not different between Group 1 and 2 (p>0.05). There were no significant changes in renal function tests and AKI biomarkers (Δserum creatinine, Δalbumin/creatinine ratio, ΔGFR, Δcystatin C, ΔNAG, and ΔNGAL) for either groups 6, 24, 72, and 168 hours after the procedures (p>0.05). Conclusions MRI without contrast agent and non-vascular contrast-enhanced (GD, 0.2 mmol/kg) MRI are not nephrotoxic procedures for patients at high risk for AKI.

Increased serum renalase in hemodialysis patients: is it related to left ventricular hypertrophy?

Abstract Introduction: Left ventricular hypertrophy (LVH) is one of the most common cardiac abnormalities in patients with end stage renal disease (ESRD). Hypertension, diabetes, increased body mass index, gender, age, anemia, and hyperparathyroidism have been described as risk factors for LVH in patients on dialysis. However, there may be other risk factors which have not been described yet. Recent studies show that renalase is associated with cardiovascular events. The aim of this study was to reveal the relation between renalase, LVH in patients under hemodialysis (HD) treatment. Methods: The study included 50 HD patients and 35 healthy controls. Serum renalase levels and left ventricle mass index (LVMI) were measured in all participants and the relation between these variables was examined. Findings: LVMI was positively correlated with dialysis vintage and C-reactive protein (CRP) (r = 0.387, p = 0.005 and r = 0.597, p < 0.001, respectively) and was negatively correlated with residual diuresis and hemoglobin levels (r = −0.324, p = 0.022 and r = −0.499, p < 0.001, respectively). There was no significant association of renalase with LVMI in the HD patients (r = 0.263, p = 0.065). Serum renalase levels were significantly higher in HD patients (212 ± 127 ng/mL) compared to controls (116 ± 67 ng/mL) (p < 0.001). Renalase was positively correlated with serum creatinine and dialysis vintage (r = 0.677, p < 0.001 and r = 0.625, p < 0.001, respectively). Discussion: In our study, LVMI was correlated with dialysis vintage, residual diuresis, CRP, and hemoglobin. LVMI tends to correlate with renalase and this correlation may be significant in studies with more patient numbers. The main parameters affecting renalase levels are dialysis vintage and serum creatinine.

Increased serum renalase in peritoneal dialysis patients: Is it related to cardiovascular disease risk?

BACKGROUND Renalase, with possible monoamine oxidase activity, is implicated in degradation of catecholamines; which suggests novel mechanisms of cardiovascular complications in patients with chronic kidney diseases. Epicardial adipose tissue (EAT) has been found to correlate with cardiovascular diseases (CVD) in dialysis patients. The present study aimed to evaluate the association of serum renalase levels with EAT thickness and other CVD risk factors in peritoneal dialysis (PD) patients. METHODS The study included 40 PD patients and 40 healthy controls. All subjects underwent blood pressure and anthropometric measurements. Serum renalase was assessed by using a commercially available assay. Transthoracic echocardiography was used to measure EAT thickness and left ventricular mass index (LVMI) in all subjects. RESULTS The median serum renalase level was significantly higher in the PD patients than in the control group [176.5 (100-278.3) vs 122 (53.3-170.0)ng/ml] (p=0.001). Renalase was positively correlated with C-reactive protein (r=0.705, p<0.001) and negatively correlated with RRF (r=-0.511, p=0.021). No correlation was observed between renalase and EAT thickness or LVMI. There was a strong correlation between EAT thickness and LVMI in both the PD patients and the controls (r=0.848, p<0.001 and r=0.640, p<0.001 respectively). CONCLUSIONS This study indicates that renalase is associated with CRP and residual renal function but not with EAT thickness as CVD risk factors in PD patients.

Fibroblast growth factor is associated to left ventricular mass index, anemia and low values of transferrin saturation

BACKGROUND Fibroblast growth factor 23 (FGF-23) is a phosphorus-regulating hormone. In chronic kidney disease (CKD), circulating FGF-23 levels are markedly elevated and independently associated with mortality. Left ventricular hypertrophy (LVH) is a potent risk factor for mortality in CKD, and FGFs have been implicated in the pathogenesis of myocardial hypertrophy. In addition, the effect of anemia on CV disease and LVH is well known in CKD. A relation between iron and FGF-23 metabolism is mentioned in a few studies. The aim of this study was to test the association of FGF-23 levels with echocardiographic (ECHO) and iron parameters in peritoneal dialysis patients (PD). METHODS In this cross-sectional study, 61 subjects with PD (29 women and 32 men, mean age: 46.9±13.3 years, mean PD vintage: 69.5±39 months) underwent echocardiograms to assess left ventricular mass index (LVMI). Medical treatments and average values of the basic laboratory results of the last 6 months for all patients were recorded. Serum FGF-23 concentrations were measured using intact FGF-23 (iFGF-23) human enzyme-linked immunosorbent assay (ELİSA) kit. According to the median levels of serum FGF-23 the patients were grouped into two (FGF-23 high and low groups). RESULTS Significant positive correlation was recorded between serum FGF-23 levels and LVMI (P=0.023). There was also significant difference in terms of hemoglobin (12.1±2 versus 11.0±2, P=0.017), transferrin saturation (TSAT) (24.9±16.8 versus 19.5±10.8, P=0.042) between low and high FGF-23 group. Also in linear regression analysis the negative relation between FGF-23 and hemoglobin is persisted (r=0.199, P=0.045). CONCLUSIONS FGF-23 is associated with LVMI, anemia and low TSAT in patients with PD. Whether increased FGF-23 is a marker or a potential mechanism of myocardial hypertrophy and anemia in patients with end-stage renal disease (ESRD) requires further study.

Does the MRI or MRI contrast medium gadopentetate dimeglumine change the oxidant and antioxidant status in humans

Background It has become evident that gadolinium-based contrast agents (GBCA) may have nephrotoxic potential. Oxidative stress is one of the most important pathways in the pathogenesis of iodinated contrast-induced nephropathy. Purpose To investigate the effects of static magnetic fields and gadopentetate dimeglumine (Magnevist®) on oxidant/antioxidant status via measurement of total antioxidant capacity (TAC), total oxidant status (TOS), and serum malondialdehide (MDA). Material and Methods Two age- and sex-matched groups of patients not under oxidative stress conditions that underwent magnetic resonance imaging (MRI) were recruited to this study. While contrast-enhanced (Magnevist®, 0.2 mmol/kg) MRI was performed in group 1, MRI without GBCA was performed in group 2. Fasting blood glucose, C-reactive protein, serum creatinine, liver enzymes, uric acid, and lipid parameters were examined in all patients. Peripheral venous blood samples in order to determine TAC, TOS, and MDA were collected before and 6, 24, and 72 h after the MRI procedures. The TOS:TAC ratio was used as the oxidative stress index (OSI). Patients were followed up to 72 h. Results There were no significant changes in serum TAC, TOS, and MDA levels (Δserum TAC, Δserum TOS, and ΔMDA) in either group 6, 24, or 72 h after the procedures (P > 0.05). Furthermore, OSI did not change after the procedures in either group (P > 0.05). Conclusion Magnetic field and gadopentetate dimeglumine (Magnevist®) do not change the oxidant or antioxidant status at a dose of 0.2 mmol/kg.

Serum apelin is associated with affective disorders in peritoneal dialysis patients

Abstract Objective: Depression and anxiety are prevalent affective disorders in peritoneal dialysis (PD) patients. Recent research has proposed a potential role of apelinergic system in pathogenesis of depression. The present study aimed to evaluate the frequency of depression and anxiety and their potential relation with serum apelin levels among PD patients. Methods: A total of 40 PD patients were enrolled into the study. Depressive symptoms and anxiety were assessed with the Beck’s Depression Inventory and the Beck’s Anxiety Inventory. Serum apelin-12 levels were measured by immunoenzymatic assays using commercially available ELISA kit for standard human apelin. Results: Of the patients, 16 (40%) had depression, 20 (50%) had anxiety. The patients with depression and anxiety had a significantly longer time on dialysis (p < 0.001 for both), significantly higher serum apelin (p < 0.001 for both) and C-reactive protein levels (p < 0.001 for both) than those without depression and anxiety. In multivariate analysis, serum apelin was the only parameter associated independently with depression and anxiety scores. Conclusions: A substantial number of PD patients had depression and anxiety. Increased levels of serum apelin may constitute a significant independent predictor of development of depression and anxiety in PD patients.

Development of High-Output Heart Failure after Correction of Central Venous Occlusion: A Case Report

Abstract Temporary or permanent central venous catheter (CVC) insertion has been performed frequently for hemodialysis treatment. One of the most important long-term complications of CVC is the central venous occlusion (CVO). Treatment of CVO consists of percutaneous angioplasty (PTA), PTA and stent implantation, or surgical procedure for resistant occlusions. Clinical outcome and long-term results of the revascularization procedures are well documented. However, there is no clear information about acute medical complications of the procedures. High-output heart failure (HOHF) is associated with several diseases including chronic anemia, psoriasis, systemic arteriovenous fistula, sepsis, hypercapnia, multiple myeloma, and hyperthyroidism. Herein, we report a case of chronic kidney disease with CVO that developed acute HOHF immediately after the revascularization procedure (PTA and stenting).