Alaattin Yildiz

Istanbul Medical University, İstanbul, Istanbul, Turkey

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Publications (80)236.04 Total impact

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    Abdullah Ozkok, Alaattin Yildiz
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    ABSTRACT: Hepatitis C virus (HCV) infection is a systemic disorder which is often associated with a number of extrahepatic manifestations including glomerulopathies. Patients with HCV infection were found to have a higher risk of end-stage renal disease. HCV positivity has also been linked to lower graft and patient survivals after kidney transplantation. Various histological types of renal diseases are reported in association with HCV infection including membranoproliferative glomerulonephritis (MPGN), membranous nephropathy, focal segmental glomerulosclerosis, fibrillary glomerulonephritis, immunotactoid glomerulopathy, IgA nephropathy, renal thrombotic microangiopathy, vasculitic renal involvement and interstitial nephritis. The most common type of HCV associated glomerulopathy is type I MPGN associated with type II mixed cryoglobulinemia. Clinically, typical renal manifestations in HCV-infected patients include proteinuria, microscopic hematuria, hypertension, acute nephritis and nephrotic syndrome. Three approaches may be suggested for the treatment of HCV-associated glomerulopathies and cryoglobulinemic renal disease: (1) antiviral therapy to prevent the further direct damage of HCV on kidneys and synthesis of immune-complexes; (2) B-cell depletion therapy to prevent formation of immune-complexes and cryoglobulins; and (3) nonspecific immunosuppressive therapy targeting inflammatory cells to prevent the synthesis of immune-complexes and to treat cryoglobulin associated vasculitis. In patients with moderate proteinuria and stable renal functions, anti-HCV therapy is advised to be started as pegylated interferon-α plus ribavirin. However in patients with nephrotic-range proteinuria and/or progressive kidney injury and other serious extra-renal manifestations, immunosuppressive therapy with cyclophosphamide, rituximab, steroid pulses and plasmapheresis should be administrated.
    World journal of gastroenterology : WJG. 06/2014; 20(24):7544-7554.
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    ABSTRACT: Resistin is an adipocytokine, associated with insulin resistance and inflammation. The aim of this study is to evaluate the levels of serum resistin levels and other markers of inflammation in hemodialysis (HD) patients with failed renal allografts. Sixty-nine HD patients with failed renal allografts and 98 never transplanted (naive) HD patients and also 21 healthy controls were included in the study. Serum levels of various biochemical parameters as well as resistin, IL-6, TNF-α and hs-CRP as biochemical markers of inflammation, were measured. Serum resistin levels in patients with failed renal allografts (4.80 ± 2.06 ng/mL) were significantly higher than those of the naive HD patients (3.44 ± 1.48 ng/mL) and healthy controls (0.95 ± 0.38 ng/mL; p<0.001). Patients with failed transplants were also characterized by higher TNF-alpha levels (96.8 ± 131.3 pg/mL vs. 40.9 ± 25.4 pg/mL; p<0.001) and IL-6 levels (83.9 ± 150.9 pg/mL vs. 14.6 ± 14.4 pg/mL; p<0.001) as compared to naive HD patients. Serum hs-CRP levels in patients with failed renal allografts (9.33 ± 11.86 mg/L) were significantly higher than those of the naive HD patients (1.26 ± 1.71 mg/L) and healthy controls (2.12 ± 1.82 mg/L; p<0.001). Serum albumin levels in patients with failed transplants (3.84 ± 0.47 g/dL) were lower as compared to never transplanted HD patients (4.13 ± 0.33 g/dL) and healthy controls (4.53 ± 0.40 g/dL; p<0.001). There was a positive correlation between serum resistin and TNF-alpha levels (r = 0.486, p<0.001). Serum resistin levels are increased in HD patients with failed renal allografts very probably reflecting an allograft-induced chronic inflammatory state.
    The International journal of artificial organs 04/2014; · 1.76 Impact Factor
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    ABSTRACT: Conversion from calcineurin inhibitor (CNI) to mTOR inhibitors may reduce and even halt the progression of chronic allograft dysfunction (CAD) which is the most important cause of renal allograft loss. We aimed to investigate the effects of conversion from CNI to everolimus on parameters of fibrosis, inflammation, glomerulotubular damage and vascular functions in renal transplant recipients. Fifteen stable renal transplant recipients who were under CNI treatment (male/female 13/2, mean age 41 ± 10 years) were enrolled and switched to everolimus. Serum and urinary transforming growth factor-β (TGF-β), urinary neutrophil gelatinase-associated lipocalin (NGAL) and monocyte chemoattractant protein-1 (MCP-1) were measured as markers of fibrosis, tubular damage and inflammation. As parameters of vascular functions, pulse wave velocity (PWV), augmentation index (AIx), serum asymmetric dimethyl-arginine and fibroblast growth factor-23 (FGF-23) were measured. All these measurements were repeated at the 3rd month of conversion. Estimated GFR (52 ± 7-57 ± 11 ml/min/l.73 m(2), p = 0.02) (was increased after conversion to everolimus. However, serum uric acid levels were significantly decreased (6.21 ± 1.21-5.50 ± 1.39 mg/dL, p = 0.01). Serum TGF-β levels (8727 ± 2897-1943 ± 365 pg/mL, p = 0.03) and urinary NGAL levels (26 ± 10-12 ± 2 ng/mg creatinine, p = 0.05) were significantly decreased. However, urinary MCP-1, FGF-23, PWV and AIx did not change. Urinary TGF-β was associated with urinary NGAL (r = 0.62, p = 0.01), urinary MCP-1 (r = 0.68, p = 0.005) and proteinuria (r = 0.50, p = 0.05). Conversion from CNI to everolimus resulted in significant decreases of serum TGF-β and urinary NGAL which may represent less fibrosis and tubular damage. Association of urinary TGF-β with NGAL and MCP-1 suggests that tubular damage, fibrosis and inflammation may act together for progression of CAD.
    Clinical and Experimental Nephrology 02/2014; · 1.25 Impact Factor
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    ABSTRACT: Disordered mineral metabolism is implicated in the pathogenesis of vascular calcification in hemodialysis (HD) patients. Fibroblast growth factor 23 (FGF-23) is the main regulator of phosphate metabolism. In this prospective study, we aimed to investigate the association of serum FGF-23 with progression of coronary artery calcification in HD patients. Seventy-four HD patients(36 male/38 female,mean age:52 +/- 14 years) were included. Serum FGF-23 levels were measured by ELISA. Coronary artery calcification score(CACS) was measured twice with one year interval. Patients were grouped as progressive (PG)(36 patients-48%) and non-progressive (NPG). Age, serum phosphorus, baseline and first year CACS were found to be significantly higher in the PG compared to NPG group. Serum FGF-23 levels were significantly higher in PG [155 (80--468) vs 147 (82--234), p = 0.04]. Patients were divided into two groups according to baseline CACS (low group, CACS <= 30; high group, CACS > 30). Serum FGF-23 levels were significantly correlated with the progression of CACS (DeltaCACS) in the low baseline CACS group (r = 0.51, p = 0.006), but this association was not found in high baseline CACS group (r = 0.11, p = 0.44). In logistic regression analysis for predicting the PG patients; serum FGF-23, phosphorus levels and baseline CACS were retained as significant factors in the model. Serum FGF-23 was found to be related to progression of CACS independent of serum phosphorus levels. FGF-23 may play a major role in the progression of vascular calcification especially at the early stages of calcification process in HD patients.
    BMC Nephrology 11/2013; 14(1):241. · 1.64 Impact Factor
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    ABSTRACT: QT dispersion (QTd) was shown to be an independent predictor of mortality in hemodialysis (HD) patients. It may be hypothesized that coronary artery calcification is related to QTd in HD patients because widespread calcification may also involve the cardiac conducting system in these patients. In this study, we aimed to investigate the relationships of corrected QTd (QTcd) with coronary artery calcification score (CACS), carotid plaque score (CPS) and possible influence of these parameters on survival of HD patients. Seventy-two HD patients (33 male, 39 female) were enrolled into the study. Mean age of the patients was 44 ± 12 years. Mean follow-up duration was 77 ± 24 months. CACS was determined by computed tomography. QTcd values were calculated as the difference of maximum and minimum QT intervals. Left ventricular mass index (LVMI) and CPS were measured by echocardiography. QTcd was significantly correlated with CACS (r = 0.233, p = 0.049), CPS (r = 0.354, p = 0.003) and LVMI (p = 0.011, r = 0.299). CPS was found to be significantly higher in the group with high QTcd (>60 ms) [2 (1-4) versus 0 (0-1), p = 0.02]. CACS was significantly correlated with age (r = 0.44, p < 0.001), LVMI (r = 0.52, p < 0.001) and CPS (r = 0.32, p = 0.003). In Kaplan-Meier analysis, survival of patients with high QTcd was significantly lower than the patients with low QTcd. In Cox regression analysis for predicting mortality, age, serum albumin and QTcd were found to be the independent predictors of mortality. QTcd independently predicted mortality, and it was significantly associated with coronary artery calcification, left ventricular hypertrophy and atherosclerosis in HD patients.
    International Urology and Nephrology 09/2013; · 1.33 Impact Factor
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    ABSTRACT: Introduction: Endothelial progenitor cells (EPC), bone marrow derived cells, are considered to have a pivotal role in maintaining the integrity and repair of the endothelium. Endothelial dysfunction, atherosclerosis and inflammation are implicated for increased CV mortality in uremia. In this study, we aimed to investigate the possible association of EPC with inflammation, endothelial dysfunction and atherosclerosis in chronic hemodialysis (HD) patients. Patients and methods: 67 HD patients (male/female: 30/37, mean age: 58 ± 15 years) and 22 healthy controls (male/female: 13/9; mean age: 48 ± 8 years) were included. EPC were cultivated in the fibronectin-covered culture dishes and counted. Also EPC markers were studied by flow cytometry using anti-CD34, anti-CD133 and anti-vascular endothelial growth factor receptor 2 (VEGFR-2) antibodies. Serum levels of IL-6, TNF-α, intercellular cell adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM) and asymmetric dimethyl-arginine (ADMA) were measured by ELISA method. Endothelial function was investigated by measuring flow-mediated dilatation (FMD) of the brachial artery. Carotid intima-media thickness (CIMT) and ratio (CIMR) were also examined. Results: EPC number was decreased in HD patients when compared to controls (63.7 ± 8.9 vs. 101.5 ± 19.6/ high power field, p < 0.001). Also CD34+ cell count was significantly lower in the HD group (2.26 ± 3.52 vs. 6.03 ± 4.73%, p < 0.0001). EPC number was significantly inversely correlated with serum TNF-α levels in HD patients(r: -0.453, p < 0.001) and also in the control group (r = -0.509, p = 0.044). There was an inverse association between VEGFR-2+/CD34+cell count and serum IL-6 levels (r: -0.364, p = 0.006) in HD patients. However, EPC count was not related to FMD and CIMT/CIMR. In HD patients, there was a positive correlation between serum IL-6 levels with CIMT (r = 0.358, p = 0.01) and CIMR was positively correlated with serum ICAM (r = 0.430, p = 0.002). Conclusion: EPC number was decreased in uremia and was associated with inflammation. TNF-α might have specific inhibitory actions on EPC in both HD patients and healthy controls. No relationship was present between EPC and endothelial dysfunction/atherosclerosis.
    Clinical nephrology 08/2012; · 1.29 Impact Factor
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    ABSTRACT: BACKGROUND: Patients with chronic HCV infection have increased liver iron. Recently identified protein hepcidin synthesized in the liver, is thought to be a key regulator for iron homeostasis and is induced by infection and inflammation. It was previously reported lower erythropoietin and iron supplementation requirement in HD patients with HCV infection. We investigated the association of prohepcidin with inflammation and iron parameters in HD patients with and without chronic HCV infection. METHODS: Sixty patients (27 male, 33 female, mean age 50 +/-15 years) on chronic HD were included. Parameters related to iron metabolism (ferritin, serum iron and total iron binding capacity (TIBC)), inflammation (hs-CRP, TNF-alpha and IL-6) and prohepcidin levels were measured. The response to treatment (erythropoiesis-stimulating agent (ESA) resistance index) was assessed from the ratio of the weekly erythropoietin (rhuEPO) dose to hemoglobin (Hb) per unit weight. RESULTS: Serum prohepcidin levels of HCV positive patients (135+/-25 ng/mL) were significantly lower than HCV negative patients [148+/-18 ng/mL, (p=0.025)]. Serum IL-6 levels of HCV positive patients were also significantly lower than HCV negative patients (p=0.016). Serum prohepcidin levels was positively correlated with ferritin (r=0.405, p=0.001) and IL-6 (r=0.271, p=0.050) levels in HD patients. In the HCV positive group, serum prohepcidin levels significantly correlated with ferritin levels (r=0.514 p=0.004). In the HCV negative group, serum prohepcidin levels significantly correlated with serum IL-6 levels (r=0.418, p=0.027). In multiple regression analysis performed to predict prohepcidin in HCV positive patients, serum ferritin was found to be an independent variable (r=0.28, p=0.008). CONCLUSIONS: HCV positive HD patients have low levels of serum prohepcidin and IL-6 which might account for iron accumulation and/or lower iron and rhuEPO requirement in these patients.
    BMC Nephrology 07/2012; 13(1):56. · 1.64 Impact Factor
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    ABSTRACT: Vascular calcification is associated with increased cardiovascular mortality in chronic hemodialysis patients. This prospective study investigated the relationship between serum osteoprotegerin, receptor activator of NF-κB ligand, inflammatory markers, and progression of coronary artery calcification score. Seventy-eight hemodialysis patients were enrolled. Serum IL-1β, IL-6, TNF-α, osteoprotegerin, receptor activator of NF-κB, fetuin A, and bone alkaline phosphatase were measured by ELISA. Coronary artery calcification score was measured two times with 1-year intervals, and patients were classified as progressive or nonprogressive. Baseline and first-year serum osteoprotegerin levels were significantly higher in the progressive than nonprogressive group (17.39±9.67 versus 12.90±6.59 pmol/L, P=0.02; 35.17±18.35 versus 24±11.65 pmol/L, P=0.002, respectively). The ratio of serum osteoprotegerin to receptor activator of NF-κB ligand at 1 year was significantly higher in the progressive group (0.26 [0.15-0.46] versus 0.18 [0.12-0.28], P=0.004). Serum osteoprotegerin levels were significantly correlated with coronary artery calcification score at both baseline (r=0.36, P=0.001) and 1 year (r=0.36, P=0.001). Importantly, progression in coronary artery calcification score significantly correlated with change in serum osteoprotegerin levels (r=0.39, P=0.001). In addition, serum receptor activator of NF-κB ligand levels were significantly inversely correlated with coronary artery calcification scores at both baseline (r=-0.29, P=0.01) and 1 year (r=-0.29, P=0.001). In linear regression analysis for predicting coronary artery calcification score progression, only baseline coronary artery calcification score and change in osteoprotegerin were retained as significant factors in the model. Baseline coronary artery calcification score and serum osteoprotegerin levels were significantly associated with progression of coronary artery calcification score in hemodialysis patients.
    Clinical Journal of the American Society of Nephrology 04/2012; 7(6):965-73. · 5.07 Impact Factor
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    ABSTRACT: Endothelial dysfunction (ED) is a key event in the development of atherosclerotic cardiovascular disease (CVD) in patients with chronic kidney disease (CKD). Association of hyperuricemia with CVD has been previously reported in the nonuremic population. In this prospective study, we aimed to evaluate the effects of treatment of hyperuricemia with allopurinol on ED and changes in the serum reactive oxygen species in patients with CKD. In this study, 19 (13 male) hyperuricemic (UA > 7 mg/dl) nondiabetic CKD patients without any comorbidity, aged < 60 years with creatinine clearance (CrCl) between 20 and 60 ml/min were evaluated. Endothelial functions were assessed by ischemia-induced forearm vasodilatation method (EDD). Oxidative stress was evaluated by measuring the serum oxidized LDL (ox-LDL), advanced oxidation protein products (AOPP) and nitrotyrosine (NT) levels. After measuring all these tests at baseline, allopurinol therapy was commenced for 8 weeks. After 8 weeks of allopurinol treatment, all measurements were repeated. Then, allopurinol treatment was ceased and same measurements were also repeated 8 weeks after ceasing of the treatment. Serum creatinine, total cholesterol, albumin, hs-CRP, CrCl and proteinuria levels of the patients were similar among three study periods. After allopurinol therapy, the mean serum UA and NT levels significantly reduced as compared to baseline. At the 8th week after cessation of allopurinol treatment, serum UA levels were significantly increased. After allopurinol therapy, EDD value increased from 5.42 ± 8.3% at baseline to 11.37 ± 9% (p < 0.001). At the 8th week after ceasing allopurinol treatment, EDD returned to baseline values (5.96 ± 8%, p < 0.001). Treatment of hyperuricemia with allopurinol improve ED in patients with CKD. However, mechanism responsible for this beneficial effect seems to be apart from antioxidant effects of allopurinol.
    Clinical nephrology 04/2012; 77(4):275-82. · 1.29 Impact Factor
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    Yasar Caliskan, Alaattin Yildiz
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    ABSTRACT: Due to organ shortage and difficulties for availability of cadaveric donors, living donor transplantation is an important choice for having allograft. Live donor surgery is elective and easier to organize prior to starting dialysis thereby permitting preemptive transplantation as compared to cadaveric transplantation. Because of superior results with living kidney transplantation, efforts including the usage of "Medically complex living donors" are made to increase the availability of organs for donation. The term "Complex living donor" is probably preferred for all suboptimal donors where decision-making is a problem due to lack of sound medical data or consensus guidelines. Donors with advanced age, obesity, asymptomatic microhematuria, proteinuria, hypertension, renal stone disease, history of malignancy and with chronic viral infections consist of this complex living donors. This medical complex living donors requires careful evaluation for future renal risk. In this review we would like to present the major issues in the evaluation process of medically complex living kidney donor.
    Journal of Transplantation 01/2012; 2012:450471.
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    ABSTRACT: The survival of patients returning to hemodialysis (HD) following kidney transplant failure is unfavorable. However, the factors responsible for this poor outcome are largely unknown; chronic inflammation due to failed allograft and malnutrition may contribute to morbidity and mortality. We aim to compare the markers of appetite and malnutrition, and their relation with inflammation in HD patients with and without previous kidney transplantation. Fifty-six patients with failed renal allografts at least 3 months on dialysis (31 men, 25 women; mean age, 46 ± 9 years) and 77 HD patients who never underwent a transplant (43 men, 34 women; mean age, 50 ± 15 years) were included in the study. The appetite and diet assessment tool (ADAT) was used to determine the self reported appetite of patients. Serum concentrations of ghrelin, leptin, insulin like growth factor 1 (IGF-1), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and high-sensitivity C-reactive protein (hs-CRP) were measured. Associations among these variables were analyzed. There were no significant differences considering age, gender or duration of renal replacement therapy between the 2 groups. The scores from Appetite and Diet Assessment Tool were significantly higher in the failed-transplant group. Serum ghrelin levels were significantly higher and serum albumin levels were significantly lower in the failed-transplant group. Serum leptin levels were similar between 2 groups. In addition, hs-CRP, IL-6, and TNF-α levels, which were used as inflammatory parameters, were significantly higher in the failed-transplant group. Elevated serum ghrelin levels and inflammation may cause diminished appetite and malnutrition in patients with failed renal allografts, and higher levels of this hormone seem to be associated with inflammation caused by retained failed allografts.
    Journal of Renal Nutrition 11/2011; 22(2):258-67. · 1.75 Impact Factor
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    ABSTRACT: Pulse pressure (PP) has been reported as an independent predictor of cardiovascular mortality in hemodialysis patients. In this study, we aimed to investigate association of PP with echocardiographic and vascular structural changes such as atherosclerosis and arterial calcifications in HD patients. In this cross-sectional study, 108 chronic hemodialysis patients (49 male, 59 female, mean age: 46 ± 13 years) were included. Biochemical analyses, echocardiographic and high-resolution carotid Doppler examinations were done. Aortic wall and coronary artery calcifications were measured with electron beam computed tomography. The degree of carotid artery stenosis was measured at four different sites (communis, bulbus, interna and externa) in both carotid arteries. PP was strongly correlated with systolic (r: 0.82) and diastolic (r: 0.33) blood pressure, left ventricular mass index (r: 0.58), left ventricle end diastolic diameter (r: 0.38) and weakly correlated with aortic wall calcification score (r: 0.26) and carotid plaque score (r: 0.27), but not with coronary artery calcification score. Patients with carotid plaque had higher PP than patients without plaque (50 ± 16 mmHg versus 44 ± 14 mmHg, P = 0.05). Patients were divided into three groups according to aortic wall calcification score. PP was significantly higher in patients with higher aortic wall calcification (54 ± 16 mmHg) than patients with lower aortic wall calcification (44 ± 15 mmHg, P = 0.04). However, on multivariate linear regression analysis for predicting PP, the only significant factor retained was left ventricle end diastolic diameter. PP was weakly associated with large vessel calcification and atherosclerosis in hemodialysis patients. The bulk of the effect on PP seems to be due to hypervolemia.
    International Urology and Nephrology 07/2011; 44(4):1203-10. · 1.33 Impact Factor
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    ABSTRACT: Hemodialysis patients have extremely increased cardiovascular mortality. Vascular calcification, inflammation, and low serum fetuin-A levels are implicated for increased mortality. In this study, relationship between coronary artery calcification, inflammation, and serum fetuin-A levels were investigated. Seventy-eight hemodialysis patients (38 male, 40 female, mean age: 52±14.5 years) were included. All patients were on dialysis for more than 6 months. Coronary artery calcium scores (CACS) are determined by electron-beam computed tomography. Serum CRP, IL-1β, IL-6, TNF-α, and serum fetuin-A levels were measured. Mean CACS value was 488.5±94.5. Serum fetuin-A levels were negatively correlated with CACS (r:-0.30, P=0.009). Patients are divided into two groups according to total CACS value; group 1 (CACS<10), group 2 (CACS≥10). There was a statistically significance difference in fetuin-A levels between CACS group 1 and group 2 (P=0.001). In this study, serum fetuin-A levels were associated with total CACS. This Fetuin-A may play a role in increased mortality in this group of patients via facilitating CAC.
    Indian Journal of Nephrology 04/2011; 21(2):90-4.
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    ABSTRACT: Decreased coronary flow reserve (CFR) is a marker of endothelial dysfunction, coronary artery calcification and inflammation, well-known cardiovascular risk factors in haemodialysis (HD) patients. In this study, we aimed to investigate the correlation of coronary artery calcification scores (CACS) with CFR in HD patients. Sixty-four end-stage renal failure patients were enrolled in this study (38 males, 26 females). Thirty-nine healthy subjects (22 males, 17 females) were included in the control group. Biochemical parameters and acute-phase inflammation marker [high-sensitivity C-reactive protein (hs-CRP)] of patients were recorded before dialysis. The CACS were measured by electron beam computerized tomography method. CFR recordings were performed by trans-thoracic Doppler echocardiography. The relationship between CACS and CFR was evaluated. The mean CACS was 281 +/- 589 and 29 patients had CACS < 10. Patients with CACS > 10 had significantly lower CFR values compared to patients with CACS < 10 (1.56 +/- 0.38 vs 1.84 +/- 0.53, P = 0.024). However, there was no difference in hs-CRP values between the groups. CFR was negatively correlated with CACS (r = -0.276, P = 0.030). In multiple stepwise regression analysis, CACS was found to be an independent variable for predicting CFR (P = 0.048). During a follow-up of 18 months, 10 patients had experience of cardiovascular events. Patients with CACS > 10 had significantly higher event rate [34.5% (10/29) vs 0% (0/24)] compared to those with CACS < 10 (P = 0.001). Patients who developed cardiovascular events had significantly higher mean CACS and lower CFR values than the remaining group (P = 0.019 and P = 0.039). All of four patients who died during follow-up were in the CFR < 2 and CACS > 10 groups. CACS was associated with CFR in HD patients. However, we did not find any association of inflammation with CACS and CFR. This association between CFR and CACS might indicate two different (anatomical and functional) aspects of the common pathophysiology of the arterial system in HD patients.
    Nephrology Dialysis Transplantation 02/2010; 25(8):2685-90. · 3.37 Impact Factor
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    ABSTRACT: Endothelial dysfunction (ED) is a common precursor and denominator of cardiovascular events including development of atherosclerosis. In this cross-sectional study, we aimed to investigate ED, measured by coronary flow reserve (CFR) in hemodialysis (nHD) patients who were never transplanted and patients with failed renal transplants restarting hemodialysis (fTx-HD). Forty nHD (24 males, mean age 39 ± 9 yr) and 43 fTx-HD patients (27 males, mean age 36 ± 9 yr) were included in the study. Clinical and biochemical parameters, including high-sensitive C-reactive protein (hs-CRP) levels were determined. Also, CFR measurements were used to evaluate ED. There were no significant differences regarding age, gender, smoking status, systolic and diastolic blood pressure levels, mean duration of HD treatment as well as Kt/V((urea)) values between the two groups. Time spent on dialysis in the nHD group and dialysis duration following failure of renal allograft in the fTx-HD group were similar. Serum creatinine, hemoglobin, hematocrit, calcium and phosphorus levels were similar between the two groups as well. When compared to nHD group, serum total cholesterol (139 ± 3 vs. 154 ± 3 mg/dL, p = 0.045), serum albumin (3.8 ± 0.3 g/dL vs. 4.1 ± 0.2 g/dL, p < 0.0001) and CFR (1.60 ± 0.2 vs. 1.75 ± 0.3, p = 0.028) levels were significantly lower, while serum hs-CRP levels (11 ± 15 mg/L vs. 3 ± 4 mg/L, p = 0.001) were significantly higher in the fTx-HD group. Serum hs-CRP negatively correlated (r = -0254, p = 0.021), while serum albumin positively correlated (r = 0402, p = 0.001) with CFR values. ED is more prominent in fTx-HD than the nHD patients. Inflammation, caused by failed renal allograft can be responsible for this abnormality.
    Clinical Transplantation 11/2009; 24(5):678-84. · 1.63 Impact Factor
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    ABSTRACT: The survival of patients returning to hemodialysis (HD) following kidney transplant failure is unfavorable. However, the factors responsible for this poor outcome are largely unknown; chronic inflammation due to failed allograft and malnutrition may contribute to morbidity and mortality. We aimed to compare the nutritional status and its relation with inflammation in patients on HD with and without previous kidney transplantation. Forty-three patients with failed renal allografts (27 males; mean age 36±9 yr) and 40 never transplanted HD patients (24 males; mean age 39±9 yr) were included in the study. Body weight, triceps (TSF), biceps (BSF), subscapular (SSSF), and suprailiac skinfold thicknesses (SISF); mid-arm, mid-arm muscle, hip and waist circumferences; as well as body mass indices (BMIs) were determined as anthropometric parameters. Moreover, biochemical markers of nutritional status, including serum cholesterol and albumin as well as high-sensitive C-reactive protein (hs-CRP), as a marker of inflammation, were measured. Associations among these variables were analyzed. There were no significant differences considering age, gender or duration of renal replacement therapy between the two groups. The TSF (p<0.0001), BSF (p=0.005), SSSF (p=0.001), SISF (p<0.0001) skinfold thicknesses; mid-arm (p=0.003) and mid-arm muscle circumferences (p=0.037) and BMIs (p=0.001) of the patients with failed renal allografts were significantly lower than those of the never transplanted HD patients. Waist circumference was significantly lower as well (p=0.028). Patients with failed transplants were characterized by lower serum albumin (p<0.0001) and higher hs-CRP levels (p=0.001) as compared with never transplanted HD patients. This study confirms the concept that retained failed allografts may induce chronic inflammation in chronic HD patients which may result in a worse nutritional status.
    Clinical Transplantation 09/2009; 24(4):481-7. · 1.63 Impact Factor
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    ABSTRACT: Hepatitis C virus (HCV) infection is associated with increased levels of inflammatory markers and is also a significant risk factor for the development of Type 2 diabetes mellitus (DM) in the general population. In attempt to address this issue in chronic hemodialysis (HD) patients, we evaluated the relation of HCV infection with inflammatory markers, endothelial dysfunction, insulin resistance and atherosclerosis. In a cohort of 72 HD patients (36 (50%) had a positive HCV EIA test and 36 (50%) had a negative anti-HCV test), we examined HCV antibody status, insulin resistance (HOMA-IR) and beta-cell function (HOMA-beta), serum inflammatory parameters (high sensitive C-reactive protein (CRP), fibrinogen and procalcitonin), and performed echocardiography, high-resolution brachial artery ultrasound and B-mode carotid Doppler examination to assess the vascular functions and atherosclerosis. There were no differences in age, gender, body mass index (BMI), primary disease, duration of dialysis, smoking status, laboratory parameters except glucose, total cholesterol and LDL cholesterol between anti-HCV-positive and anti-HCV-negative groups. The serum concentrations of glucose, total cholesterol and LDL cholesterol were significantly lower in the anti-HCV-positive patients than anti-HCV-negative patients (p = 0.04, p = 0.02, p = 0.01, respectively). There were no significant differences in inflammatory parameters, total insulin secretion (HOMA-beta, p = 0.76) and insulin resistance (HOMA-R, p = 0.91) between anti-HCV-positive and negative patients. The intima media thickness, carotid plaque score and brachial artery endothelium-dependent dilatation did not differ significantly between the two groups (p = 0.44, 0.45, and 0.17, respectively). HCV infection was not related to atherosclerosis and insulin resistance in hemodialysis patients. Since hemodialysis patients had a large number of uremia-related cardiovascular risk factors, the effect of HCV infection could disappear in this group of patients.
    Clinical nephrology 03/2009; 71(2):147-57. · 1.29 Impact Factor
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    ABSTRACT: The effect of pre-transplant dialysis modality on early graft function is a matter of debate. Although some authors deny the existence of a significant influence, others suggest that peritoneal dialysis (PD) affects early graft function favorably, possibly by contributing to a more physiologic water balance. In the present study, we evaluated the influence of pre-transplant dialysis modality on early and late graft function. We studied 745 patients who underwent a first renal transplantation during 1983-2006, comparing the records of 44 PD patients [26 male; mean age: 26 +/- 9 years (range: 8-56 years)] who received 36 living related and 8 cadaveric renal transplantations with those of a control group of 44 consecutive hemodialysis (HD) patients [26 male; mean age: 27 +/- 11 years (range: 7-49 years)] for the index cases. The groups showed no significant differences in donor type, human leukocyte antigen matching, immunosuppressive protocols, and duration of dialysis. Also, neither group differed significantly with regard to incidence of delayed graft function, acute tubular necrosis, wound infection, systemic viral and bacterial infections, or acute rejection in the early post-transplant period. In the late post-transplant period, incidences of chronic rejection, graft failure, and malignancies were also similar. During the follow-up period, 3 patients in the PD group experienced acute rejection, 2 developed cytomegalovirus (CMV) disease, and 5 developed various other infections. In the HD group, 4 patients experienced acute rejection, 1 developed CMV disease, and 8 experienced other infections. Five patients in the PD group and one in the HD group died with functioning grafts (p = 0.09). No differences were noted between the groups in the incidences of post-transplant cardiovascular complications, malignancies, and diabetes mellitus. In the PD group, 33 patients with functioning grafts are still being followed, 6 have returned to dialysis, and 5 have died. In the HD group, 38 patients with functioning grafts are still being followed, 5 have returned to dialysis, and 1 has died. As a pre-transplant dialysis modality, neither HD nor PD affects the outcome of renal transplantation.
    Peritoneal dialysis international: journal of the International Society for Peritoneal Dialysis 02/2009; 29 Suppl 2:S117-22. · 2.21 Impact Factor
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    ABSTRACT: Non-convulsive status epilepticus (NCSE): a condition that may be associated with different levels of altered consciousness without any apparent motor signs. There are published reports that it may be associated with antibiotic use patients with renal failure. This is a retrospective analysis of our 12 NCSE (2 men, 10 women, a mean age: 58.4 +/- 17.5 range of 29-85 years) patients with renal failure who have used antibiotics. Twelve patients were receiving a total of 19 antibiotics including mainly beta-lactams. The mean duration of time between start of antibiotic treatment and NCSE was 8.0 (3-21) days. In all of the patients, neurological symptoms were slowly progressive and consisted of depression of consciousness and/or disorientation. Diazepam administration resulted in marked reduction or completely disappears of epileptic activity. Four of 12 patients (33%) died, but none of were associated with NCSE but primarily associated with infection developed secondary to the preexisting disease and with congestive heart failure which patients already had. Antibiotics, especially beta-lactams could be neurotoxic and may cause of NCSE. NCSE should be considered in patients with unexplained loss of consciousness; EEG must be a part of investigations in patients with uraemia receiving antibiotics.
    Clinical and Experimental Nephrology 01/2009; 13(2):138-44. · 1.25 Impact Factor
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    ABSTRACT: Background. In previous studies, the oral and dental health statuses were compared in hemodialysis (HD) and peritoneal dialysis (PD) patients without taking into account the effect of educational levels on oral health. Hence we aimed to make a comparison of these parameters based upon the subjects educational levels. Patients and Methods. 76 PD (33 males, 43 females-mean age: 44 +/- 12 years) and 100 HD (56 males, 44 females-mean age: 46 +/- 14 years) patients were included. The number of decayed, missing and filled teeth were detected, DMFT index was calculated and plaque index (PI) values were assessed. Results. Significantly higher numbers of filled teeth (P < .001) and lower PI values (P < .01) in the PD group were detected with higher educational levels, whereas no significance was detected in the HD group. Higher DMFT index values were assessed in the lower educated and high school levels in PD than HD patients (P < .05). Higher numbers of filled teeth (P < .05) were detected in the secondary school level in PD patients. This difference was even more significant in the high school level (P < .001). Conclusion. We assume that PD patients, who were found to be in a higher educational level, are more caring for their oral health as compared to HD patients.
    International Journal of Dentistry 01/2009; 2009:159767.

Publication Stats

823 Citations
236.04 Total Impact Points

Institutions

  • 2014
    • Istanbul Medical University
      İstanbul, Istanbul, Turkey
  • 1996–2013
    • Istanbul University
      • • Department of Nephrology
      • • Faculty of Dentistry
      • • Department of Family Medicine (Istanbul Medical Faculty)
      • • Department of Infectious Diseases
      İstanbul, Istanbul, Turkey
  • 2006–2011
    • Selcuk University
      • Division of Nephrology
      Konya, Konya, Turkey
  • 2009
    • Haseki Training and Research Hospital
      İstanbul, Istanbul, Turkey
  • 2004
    • Vanderbilt University
      • Department of Internal Medicine
      Nashville, MI, United States