Publications (14)23.52 Total impact
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Article: Lower serum prohepcidin levels associated with lower iron and erythropoietn requirements in hemodialysis patients with chronic hepatitis C.
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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. · 2.18 Impact Factor -
Article: Outcome of patients with amyloidosis after renal transplantation: a single-center experience.
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ABSTRACT: The prognostic outcome of patients with amyloidosis who receive a kidney transplant is controversial. The aim of the study was to analyze the renal transplantation outcome of patients with amyloidosis compared to transplant recipients with other kidney diseases. Among 940 patients who had renal transplantation in our unit between 1983 and 2009, 44 patients with amyloidosis were compared regarding early and late complications and survival, retrospectively, with a control group of 41 consecutive patients with the same donor type and a matched renal transplantation date. The groups were similar regarding demographic parameters, HLA mismatch numbers and mean follow-up period. Groups were similar regarding early and late infectious and non-infectious complications, except recurrence of the primary disease, which was more common in the amyloidosis group. As the cause of graft loss, rejection (acute or chronic) was more common in the control group; whereas primary non-functioning graft, and death with a functioning graft were more common in the amyloidosis group. Patient survival rates at 1, 5, and 10 years were 87.6%, 78.1%, and 62.3 in the amyloidosis group; and 93.2%, 82.6%, and 69.3% in the control group. Graft survival rates at 1, 5 and 10 years were 87.6%, 75.4%, 56.4% in the amyloidosis group; and 93.2%, 80.3%, and 60.6% in the control group, respectively. These values did not show any statistical difference. The outcomes of renal transplantation in patients with amyloidosis are comparable with recipients whose primary problems are due to other kidney diseases; therefore, amyloidosis patients should be accepted as good candidates for transplantation.The International journal of artificial organs 05/2012; 35(6):444-9. · 1.86 Impact Factor -
Article: Reduction of uric acid levels with allopurinol treatment improves endothelial function in patients with chronic kidney disease.
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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. · 1.17 Impact Factor -
Article: Comparison of markers of appetite and inflammation between hemodialysis patients with and without failed renal transplants.
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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. · 1.57 Impact Factor -
Article: Effects of arteriovenous fistula on clinical, laboratory and echocardiographic findings in renal allograft recipients.
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ABSTRACT: Left ventricular hypertrophy (LVH) is frequently observed in patients with end-stage renal disease and renal allograft recipients, and is an independent and strong predictor of morbidity and mortality. Presence of a patent arteriovenous fistula (AVF) after renal transplantation may contribute to the persistent LVH. We investigated the clinical, laboratory, and echocardiographic findings in patients with renal transplants with or without AVF. A total of 130 renal transplant recipients were included in this study: 60 hemodialysis patients whose fistulas were still functional, 49 hemodialysis patients whose fistulas were spontaneous stopped or closed, and 21 peritoneal dialysis patients who had never had fistulas created. Laboratory parameters were measured and echocardiographic measurements were performed. There were no significant differences regarding smoking status, blood pressures, or NT-proBNP, hs-CRP, iPTH, and TSH levels between the study groups. Left atrial, right atrial diameters, left ventricle end-diastolic diameter, left ventricle end-systolic diameter, interventricular septum thickness (IVST), left ventricle mass index (LVMI), pulmonary artery pressure (PAP), and ejection fraction were similar in the three groups. In correlation analysis, PAP was significantly correlated with serum uric acid and NT-proBNP levels. Also, there were positive and moderate correlations between the serum uric acid and the IVST. Patent AVFs have not affected cardiovascular abnormalities such as LVH and LV mass index in patients with renal transplant. Hyperuricemia may be associated with increased PAP and high LVMI.The International journal of artificial organs 10/2011; 34(10):1024-30. · 1.86 Impact Factor -
Article: Serum uric acid level is associated with cardiac hypertrophy in renal transplant recipients.
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ABSTRACT: Serum uric acid (UA) level as a significant and independent risk factor for cardiovascular disease, and the link between this marker and left ventricular hypertrophy (LVH) in renal transplant recipients remains to be clarified. A total of 141 renal transplant recipients (83 men), between ages of 18 and 69 (mean age 37 ± 11), were included in this single center study. In addition to demographic, clinical, and laboratory parameters, serum UA concentrations were evaluated. LVH was determined by two-dimensional and M-mode echocardiography. Serum UA levels were significantly higher (6.14 ± 1.15 mg/dL) in patients with LVH (n = 54) when compared to patients (n = 87) who did not have this abnormality (5.29 ± 1.43 mg/dL) (p = 0.006). Serum UA levels were significantly correlated with septal wall thickness, LV posterior wall thickness, LV mass index (LVMI), and pulmonary arterial pressure. Multiple linear regression analysis revealed that UA predicted LVMI (r(2) = 0.150, β = 0.369, p = 0.001). However, serum creatinine (β = 0.060, p = 0.593) and age (β = 0.146, p = 0.175) were not predictors of LVMI. High serum UA levels are associated with LVH in renal transplant recipients, which underlines the importance of treating hyperuricemia.Clinical Transplantation 05/2011; 25(3):368-74. · 1.67 Impact Factor -
Article: Conversion to sirolimus in renal transplant recipients: a single-center experience.
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ABSTRACT: Maintenance immunosuppression with calcineurin inhibitors (CNI) following renal transplantation is associated with nephrotoxicity and accelerated graft loss. Sirolimus (SRL) is a nonnephrotoxic immunosuppressive agent. We retrospectively analyzed our experience with kidney transplant recipients who were converted from CNI to SRL. A total of 58 renal transplant recipients were converted from CNI to SRL. SRL was started at a dose of 0.075 mg/kg and, at the same time, CNI dose was reduced by 50% daily for 3 days. SRL trough levels were targeted between 8 and 12 ng/mL. When target trough levels were achieved, CNI was withdrawn. The main indications for switching were posttransplant malignancies (n = 32) and chronic allograft nephropathy (CAN) (n = 10). The mean time from transplantation to conversion was 84 +/- 71 months. Mean serum creatinine level was 1.63 +/- 0.52 mg/dL before conversion. Serum creatinine levels at the 1, 3, 6 months, and 1, 2, 3 years after conversion were 1.64 +/- 0.58 mg/dL (P = 0.67), 1.52 +/- 0.53 mg/dL (P = 0.414), 1.62 +/- 0.62 mg/dL (P = 0.734), and 1.48 +/- 0.58 mg/dL (P = 0.065), 1.58 +/- 0.53 mg/dL (P = 0.854), 1.88 +/- 0.77 mg/dL (P = 0.083), respectively. Daily proteinuria levels increased from 0.04 +/- 0.11 g/day at baseline to 0.55 +/- 1.33 g/day (P = 0.037) after conversion, in the responders group. In the nonresponders group, baseline proteinuria was 0.13 +/- 0.25 g/day, and increased to 1.44 +/- 2.44 g/day after conversion (P = 0.008). SRL was discontinued in 16 patients (31%) because of the occurrence of severe side effects. The proportion of patients remaining on SRL therapy over time was 43.1% at 1 year, 15.5% at 2 years after conversion, and 10.3% at 3 years after conversion. SRL conversion may be very useful in patients suffering from neoplasia; however, frequent side effects related with this intervention should be considered, and routine conversion from CNI to SRL to reduce nephrotoxicity should be discouraged.Artificial Organs 08/2010; 34(8):E230-7. · 2.00 Impact Factor -
Article: Does pregnancy increase graft loss in female renal allograft recipients?
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ABSTRACT: Although many transplanted women who were previously infertile can conceive during the posttransplant period, maternal and fetal complications are likely. We evaluated the effect of pregnancy after renal transplantation in this study. We retrospectively evaluated female renal transplant recipients who became pregnant. Age- and transplantation time-matched nonpregnant patients were used as a control group. We analyzed data regarding the demographic features of the pregnant patients, their serum creatinine levels before pregnancy, during pregnancy and during the postpartum period until now, immunosuppressive drugs, complications during pregnancy and fetal complications. In total 57 patients were included in this study. We divided the transplanted patients into two groups: 22 deliveries in 19 patients (delivery group) and 38 nonpregnant patients (control group). The mean follow-up durations and ages of transplantation were similar in the two groups. There was no significant difference in the mean serum creatinine values of the two groups (p = 0.42). Regarding immunosuppressive drugs, there was no significant difference between the two groups (p = 0.23). The frequencies of chronic hypertension, proteinuria, use of erythropoietin, and urinary tract infection were not statistically significantly different between the two groups (p = 0.31, 0.59, 0.36, 0.28, respectively). There were also no significant differences noted in graft and patient survival between the groups (p = 0.577). Female transplant recipients who have stable creatinine levels, insignificant proteinuria, and normal blood pressure or controlled hypertension may become pregnant, and they can have successful pregnancies. Their graft functions and survivals are not affected by gestation.Clinical and Experimental Nephrology 06/2010; 14(3):244-7. · 1.37 Impact Factor -
Article: Coronary artery calcification and coronary flow velocity in haemodialysis patients.
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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. · 3.40 Impact Factor -
Article: Outcomes of renal transplants from spousal donors: 25 years of experience at our center.
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ABSTRACT: Objectives: Many transplantation teams have attempted renal transplants from living unrelated kidney donors, as well as from cadaveric and living related kidney donors. In this study, we evaluated the results for renal transplants from spousal donors at our center. Methods: We retrospectively analyzed renal transplant patients from spousal donors from 1983 to 2008. A total of 25 patients who underwent a cadaveric donor renal transplant from 1983 to 2008 were also studied as a control group. Patients were evaluated regarding patient and graft survival at 1 and 5 years of follow-up. Acute rejection, delayed graft function, infections, and late complications were recorded. Results: Thirty-eight male, spousal transplant recipients (group 1), 21 female, spousal transplant recipients (group 2), and 25 cadaveric donor transplant recipients were included this study. Graft survival rates were 96% in group 1 and 100% in group 2 (p=0.76) at 1-year follow-up. Patient survival rates in group 1 and 2 were both 100% at 1-year follow-up. Graft survival rates were 80% in group 1 and 100% in group 2 (p=0.12) at 5-year follow-up. Patient survival rates were 90% in group 1 and 100% in group 2 (p=0.56) at 5-year follow-up. Acute rejection rates were 10% (group 1) and 33% (group 2) (p=0.03); delayed graft function rates were 0% (group 1) and 10% (group 2) (p=0.05); infection rates were 16% (group 1) and 5% (group 2) (p=0.21) as early period posttransplant complications. Conclusion: Results for transplants between spouses in our groups were comparable to those previously reported in the literature. Acute rejection rates were mildly higher in female recipients than in the male recipients due to pre-sensitization arising from previous pregnancies; however, long-term patient and graft survival rates were not significantly different between female and male recipients.The International journal of artificial organs 01/2010; 33(1):40-44. · 1.86 Impact Factor -
Article: Endothelial dysfunction in hemodialysis patients with failed renal transplants.
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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. · 1.67 Impact Factor -
Article: Effect of pre-transplant dialysis modality on kidney transplantation outcome.
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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. · 2.10 Impact Factor -
Article: Plasma ghrelin levels are associated with coronary microvascular and endothelial dysfunction in peritoneal dialysis patients.
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ABSTRACT: Cardiovascular (CV) disease is the main cause of death in peritoneal dialysis (PD) patients, and endothelial dysfunction (ED) is an early sign of vascular pathology. Ghrelin, a gastric peptide with CV actions, has been shown to inhibit proatherogenic changes in experimental models. However, another peptide hormone, leptin, may mediate deleterious effects on the CV system. The aim of this study is to evaluate the relationship between plasma ghrelin and leptin levels, and their association with coronary microvascular and endothelial functions in PD patients. Twenty-four (14 females and 10 males; mean age 44 +/- 12 yr) nondiabetic PD patients, between 18 and 70 years of age, were enrolled. In addition to demographic, clinical, and laboratory parameters, plasma concentrations of ghrelin and leptin were evaluated. Endothelial functions of the coronary arteries were determined by coronary flow reserve (CFR) measurement using transthoracic Doppler echocardiography (TTDE). A CFR value of < 2 was used as an evidence for ED. When the study group was divided according to CFR measurements as CFR < 2 and >or= 2, there were no significant differences considering age, gender, etiology of renal disease, body mass index (BMI), duration of dialysis, PD modality, PD solution type, history of peritonitis, mean arterial pressure, ejection fraction, and biochemical parameters between the two subgroups. Plasma ghrelin levels (129.4 +/- 82.1 pg/mL) in patients with CFR >or= 2 were significantly higher than those in patients with CFR< 2 (63.3 +/- 35.8 pg/mL) (p = 0.03). However, no significant differences in plasma leptin levels were found between these groups [31.39 +/- 37.81 ng/mL vs. 63.95 +/- 72.83 ng/mL (p = 0.28)]. No correlation existed between plasma ghrelin levels and age, BMI, duration of dialysis, mean arterial pressure, ejection fraction, plasma leptin levels, and biochemical parameters. Decreased plasma ghrelin levels may contribute to the development of atherosclerosis in PD patients by causing ED.Renal Failure 01/2009; 31(9):807-13. · 0.82 Impact Factor -
Article: Focal segmental glomerulosclerosis associated with Good's syndrome
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2012
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Haseki Training and Research Hospital
İstanbul, Istanbul, Turkey
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2009–2012
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Istanbul University
- Department of Nephrology
İstanbul, Istanbul, Turkey
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