Papers by Mehmet Buyukbakkal
Türk Nefroloji Diyaliz ve Transplantasyon Dergisi, 2012
Turkish Nephrology Dialysis Transplantation, 2017
Nephrology Dialysis Transplantation, 2014
Introduction and Aims: Premature cardiovascular disease limits the quality and length of life on ... more Introduction and Aims: Premature cardiovascular disease limits the quality and length of life on long-term haemodialysis. The epidemiology of cardiovascular events in this context needs to be better defined and more effective management strategies developed. Adjudicated cardiovascular event data collected during the Evaluation of Cinacalcet HCl Therapy to Lower Cardiovascular Events (EVOLVE) Trial were used to define the frequency of fatal and non-fatal cardiovascular events attributable to atherosclerotic and non-atherosclerotic mechanisms. The risk factors for these events and the impact of assignment to treatment with cinacalcet or placebo were evaluated. Methods: A multicenter, global, randomized, double-blind, placebo-controlled clinical trial assessing mortality and non-fatal cardiovascular events in 3883 patients on haemodialysis with secondary hyperparathyroidism (median parathyroid hormone concentration 693 pg/mL (10%, 90% range 363 to 1694 pg/mL). The post hoc outcome meas...
Nephrology Dialysis Transplantation, 2013
Introduction and Aims: High permeability in peritoneal dialysis (PD) patients had been reported t... more Introduction and Aims: High permeability in peritoneal dialysis (PD) patients had been reported to be associated with increased mortality. Cardiovascular disease is the most important cause of morbidity and mortality in patients with end-stage renal disease. The inflammation is thought to take part in development of atherosclerosis. The aim of this study is to investigate the relationship of peritoneal permeability type with carotid intima media thickness (CIMT) in PD patients. Methods: Based on the standard peritoneal equilibration test, 56 PD patients (28 male/ 28 female) were divided in two transporter groups: LOW (Low+Low average) and HIGH (High+High average) permeability. C-reactive protein (CRP) was measured as a marker of inflammation and CIMT was evaluated by high-resolution B-mode ultrasonography. Results: 21 patients were LOW and 35 were HIGH transporters. Mean CRP level was significantly higher in the HIGH permeability group compared to LOW group (1.62 ±1.7mg/L vs. 0.84±1.00mg/L respectively, p=0.006). CIMT was higher in the HIGH group but this difference did not reach statistical significance (0.81±0.16 vs. 0.74±0.16, p=0.16). Conclusions: CRP, an indicator of inflammation, was found to be higher in the high transporter group. Also CIMT was found to be higher in high transporter group although it was not statistically significant. One of the causes of increased mortality rate in this group of patients may be explained by inflammation and atherosclerosis.
Nephrology Dialysis Transplantation, 2016
Renal Failure, 2016
Objective: Depression and anxiety are prevalent affective disorders in peritoneal dialysis (PD) p... more 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.
Hemodialysis International, 2015
Atherosclerotic cardiovascular disease is an important cause of mortality and morbidity in hemodi... more 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 &amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01, R = 0.33) and hepcidin-25 (P &amp;amp;amp;amp;amp;amp;amp;amp;lt; 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.
Renal Failure, 2015
Atherosclerotic cardiovascular disease is one of the major causes of mortality and morbidity in p... more Atherosclerotic cardiovascular disease is one of the major causes of mortality and morbidity in peritoneal dialysis (PD) patients. S100A12 is an endogenous receptor ligand of advanced glycation end-products. It was shown to contribute to the development of atherosclerosis in animal models. The aim of this study was to evaluate the relationship between S100A12 levels and carotid atherosclerosis in PD patients. A cross-sectional study was performed in 56 PD patients and 20 control subjects. Plasma S100A12 levels were measured from all participants beside routine laboratory evaluation. All subjects underwent high-resolution B-mode ultrasonography to determine carotid intima media thickness (CIMT). S100A12 levels were compared between patient and control groups. Correlation analyses of S100A12 with other laboratory values and CIMT were also performed. Plasma S100A12 levels were higher in PD patients compared with control subjects (129.5 ± 167.2 ng/mL vs. 48.5 ± 30.3 ng/mL, respectively, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). In the patient group, CIMT was found to be positively correlated with age (r = 0.354; p = 0.007), CRP level (r = 0.269; p = 0.045), and S100A12 (r = 0.293; p = 0.028) level while it was found to be negatively correlated with hemoglobin concentration (r = -0.264; p = 0.049). In the linear regression analysis, the model, including CRP, S100A12, age, and Hgb, was found to be significant (F: 4.177, p: 0.005). When the parameters are analyzed age and S100A12 were found to be independent determinants of CIMT (β = 0.308, p = 0.018 and β = 0.248, p = 0.049, respectively). This study suggests that an elevated plasma S100A12 level was closely associated with atherosclerosis. With aging elevated plasma S100A12 may show a powerful proatherogenic potential in patients undergoing PD.
Renal Failure, 2015
Abstract Background: Cardiovascular disease (CVD) is the most important cause of morbidity and mo... more Abstract Background: Cardiovascular disease (CVD) is the most important cause of morbidity and mortality in patients with end stage renal disease (ESRD). Apelin expressed in endothelial and other tissues including brain and kidney is an adipocytokine defined recently and is emerging an important mediator of cardiovascular homeostasis. The aim of this study was to test whether apelin levels might be associated with carotid artery atherosclerosis and left ventricular mass index (LVMI) in peritoneal dialysis patients. Patients and methods: Fifty peritoneal dialysis patients (25 female, mean age 41.4 ± 11.9 years, mean dialysis vintage 65.0 ± 35.4 months) and 18 healthy individuals (9 female, mean age 41.7 ± 6.8 years) were included in this cross-sectional study. Serum apelin 12 levels, echocardiographic findings and carotid intima media thickness (CIMT) were recorded as well as clinical and laboratory data. Results: There were no differences between the patient and the control groups with regard to demographic characteristics. In patient group, LVMI, CIMT, CRP and apelin levels were elevated compared to control group. However there was no association between apelin, LVMI and CIMT. There was a positive correlation between apelin and CRP, which was not statistically significant. When patients were divided into two groups according to the mean serum apelin levels, LVMI, CIMT and CRP were higher in the high apelin group but this difference did not reach statistical significance. Conclusion: We observed an increased inflammation and CVD risk in peritoneal dialysis patients. However, serum apelin levels seem not to be associated with cardiovascular risk in this group of patients.
Turkish Nephrology Dialysis Transplantation, 2012
Nefrología, 2015
Fibroblast growth factor 23 (FGF-23) is a phosphorus-regulating hormone. In chronic kidney diseas... more 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). 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). 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). 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.
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Papers by Mehmet Buyukbakkal