Biomedical subjects

Tayfun Eyileten

Publications and source records attributed to Tayfun Eyileten.

8 recordsLinked to original sources

PubMed2006

Hyperbaric oxygen treatment augments the efficacy of a losartan regime in an experimental nephrotic syndrome model.

BACKGROUND/AIMS: Proteinuria is associated with oxidant stress and inflammation. Hyperbaric oxygen (HBO) treatment has anti-inflammatory and anti-oxidant effects. The aim of the study was to investigate the benefits of HBO treatment on an experimental nephrotic syndrome model. METHODS: 50 male Sprague-Dawley rats weighing 255 +/- 39 g were housed. Forty rats were injected 6 mg/kg adriamycin into tail veins under anesthesia to induce nephrosis, while 10 rats were spared as sham control. After the stabilization of proteinuria at the sixth week, the rats were treated for 6 weeks by losartan (n = 10, 30 mg/kg/day), HBO (n = 10, 2.8 atmosphere absolute, 90 min/day), HBO + losartan (n = 10) and vehicle (n = 10). Protein carbonyl (PCO), superoxide dismutase (SOD) and glutathione peroxidase (GPx) were analyzed from tissue specimens. Biochemical markers were studied from venous samples and 24-hour urine was collected for proteinuria. The surviving animals at 12 weeks (vehicle group (n = 6), HBO (n = 6), losartan (n = 8), HBO + losartan (n = 10) were sacrificed. Glomerular sclerosis, tubulointerstitial and blood vessel changes were determined by semiquantitative scoring. RESULTS: The PCO levels increased (p < 0.001), and the GPx and SOD levels decreased (p < 0.001 for both) in the nephrotic rats. In losartan and HBO groups GPx levels increased (p = 0.001, p = 0.002 respectively), but PCO and SOD levels did not change. The combination of HBO with losartan significantly increased the GPx and SOD levels (p = 0.001 for both) and decreased PCO levels (p = 0.005). HBO but not losartan significantly reduced proteinuria (p < 0.001). The combination of HBO and losartan reduced proteinuria better than the single losartan regime (p < 0.001). The effect of the combination was also noticed on the histological examination of the kidneys. The activities, appetites, weight gains, and improvement of edema were better in the HBO combined with losartan regime. CONCLUSIONS: These results indicate that the addition of HBO therapy to a conventional regime, angiotensin receptor blockers, has significant benefits in the management of proteinuria. Future clinical studies are needed to elucidate the role of HBO and other antioxidant strategies in the treatment of proteinuria.

Animals↗

PubMed2006

Asymptomatic kindred of patients with coronary events have increased peripheral T-cell activities.

T cells are involved in the pathogenesis of atherosclerosis. We aimed to search for any association between the peripheral T-cell activities and atherogenic risk factors in healthy subjects. Fifty male volunteers (age 22.0 +/- 2.4 years) were enrolled. No subject had any chronic disease or was under any drug treatment. Lymphocytes were isolated from heparinized venous blood and the proliferative responses to phytohemagglutinin (PHA) were measured from the amount of radioactive thymidine uptake by the lymphocyte DNA. T-cell activity responses of patients with a family history of coronary events were compared with others. The activity responses of smokers were compared with nonsmokers. Subjects with a positive family history of coronary events had higher PHA stimulated T-cell response and delta cpm (P < 0.05 for each). Total and low-density lipoprotein cholesterol levels of the subjects with a positive family history of cardiovascular events were positively correlated with the PHA-activated T-cell responses (P = 0.022, r = 0.604 and P = 0.015, r = 0.635, respectively). There was no significant difference between the T-cell activity responses of smokers and nonsmokers. No correlation was found between the biochemical parameters and T-cell activities in these groups. Peripheral T-cell activity responses to PHA are higher in the asymptomatic relatives of patients with coronary events. This may be a clue for the familial tendency of atherosclerotic diseases. Further follow-up studies are necessary to investigate the relationship.

Adult↗

PubMed2006

The determinants of endothelial dysfunction in CKD: oxidative stress and asymmetric dimethylarginine.

BACKGROUND: Oxidative stress is related to endothelial dysfunction (ED) and cardiovascular outcomes in patients with chronic kidney disease. Increased asymmetric dimethylarginine (ADMA) levels are among the main causes of ED. We aim to investigate any association between ED and ADMA levels, as well as levels of oxidative stress markers, in patients with chronic kidney disease. METHODS: One hundred fifty-nine patients without diabetes with chronic kidney disease were studied. Staging was performed according to glomerular filtration rate, determined as stages 1 to 5 according to the Kidney Disease Outcomes Quality Initiative (n = 30, 33, 28, 32, and 36, respectively). The control group consisted of 30 healthy subjects. Oxidative stress markers (plasma malondialdehyde [MDA], erythrocyte superoxide dismutase [SOD], glutathione peroxidase [GSH-Px]), trace elements (erythrocyte zinc [EZn], erythrocyte copper [ECu]), plasma selenium (Se), and serum ADMA were studied. Brachial artery endothelium-dependent vasodilatation (FMD) was calculated for all. RESULTS: FMD, SOD, GSH-Px, EZn, ECu, and Se values were lower, whereas MDA and ADMA levels were higher in patients than controls. Glomerular filtration rate correlated negatively with MDA and ADMA levels and positively with FMD, SOD, and GSH-Px values. These parameters were significantly different among patients with stages 2, 3, 4, and 5 (hemodialysis group; P < 0.001 for all). Regression analysis showed that ADMA (beta = -0.228; P < 0.01), SOD (beta = 0.405; P < 0.001), and oxidized low-density lipoprotein levels (beta = -0.428; P < 0.001) were related independently to FMD, whereas glomerular filtration rate was not involved in the model. CONCLUSION: The present results imply that FMD, oxidative stress, and ADMA levels all are associated with stage of chronic kidney disease. Additionally, levels of oxidative stress markers and ADMA independently determine endothelial function.

Adult↗

PubMed2006

Plasma adiponectin and insulin resistance in new onset hypertension.

OBJECTIVE: The data related to association among hypertension, insulin resistance, and plasma adiponectin concentration is controversial. We aimed to evaluate the relationships among these factors in a young hypertensive group who had no confounding factors. DESIGN AND METHODS: Thirty newly diagnosed and formerly untreated hypertensive males (mean age 23.4 +/- 4.0 yr; body mass index: 24.9 +/- 2.2 kg/m2), and 60 healthy control subjects (mean age 22.5 +/- 3.2 yr; body mass index: 24.6 +/- 1.6 kg/m2) were enrolled. Insulin resistance was calculated by homeostasis model assessment (HOMA). RESULTS: The two groups were similar in terms of age, body mass index, fasting glucose, total cholesterol, HDL and LDL cholesterol, adiponectin, insulin, HOMA, and hsCRP levels. Mean triglyceride levels in hypertensive patients were significantly higher than the controls (p = 0.02). CONCLUSIONS: These results indicate that young, newly diagnosed, uncomplicated patients with hypertension have similar plasma adiponectin levels and insulin sensitivities when compared to healthy controls. We suggest that high blood pressure itself may not be associated with insulin resistance or low adiponectin levels in patients with new onset, uncomplicated hypertension.

Adiponectin↗

PubMed2005

Endothelial functions improve with decrease in asymmetric dimethylarginine (ADMA) levels after renal transplantation.

BACKGROUND: Chronic kidney disease (CKD) is associated with increased cardiovascular events. The relationships between the markers of inflammation and endothelial dysfunction were investigated both before and after living donor kidney transplantation. METHODS: Twenty-seven renal transplant patients were studied. Eleven patients (six male, five female) were on cyclosporine A, whereas 16 patients (nine male, seven female) were treated with tacrolimus based regimes. Twenty-seven subjects (12 males, 15 females) were studied as controls. Plasma adiponectin, high sensitive C reactive protein (hsCRP), Asymetric dimethyl arginine (ADMA) levels were studied before transplantation and on days 1, 3, 7, 14, and 28. The brachial artery flow mediated dilatation (FMD) was studied before transplantation and on the 28th day. RESULTS: Serum hsCRP and ADMA levels decreased significantly from the first posttransplantation day on each measurement (P<0.001 for all) while the decrement of plasma adiponectin started in the third day (P<0.001 for all). The FMD was lower in the patients than the control group (P<0.001) and improved significantly in the 28th day of transplantation (P<0.001). CONCLUSIONS: The results indicate that ADMA is associated with FMD in CKD both before and after kidney transplantation. Endothelial functions improve at the very beginning of the posttransplantation period with accompanying reduction in ADMA and hsCRP levels.

Adult↗

PubMed2005

Assessment of oxidative stress in the early posttransplant period: comparison of cyclosporine A and tacrolimus-based regimens.

BACKGROUND: Oxidative stress is one of the leading causes of cardiovascular morbidity and mortality in chronic kidney disease. Although it is clear that many metabolic abnormalities improve, the effects of kidney transplantation on oxidative state are obscure. METHODS: Twenty-three kidney transplant patients were included in the study. Eleven patients (mean age 27.9+/- 9.1 years) were treated with cyclosporine A (CsA) whereas 12 patients (mean age 22.4 +/- 3.4 years) were treated with tacrolimus. Twenty-three healthy subjects served as controls. None of the patients or controls suffered from diabetes mellitus or an acute infection at the time of the study. Plasma malondialdehyde (MDA), plasma selenium (Se), erythrocyte glutathione peroxidase (GSH-Px), erythrocyte superoxide dismutase (SOD), erythrocyte Zn (EZn), and erythrocyte Cu (ECu) levels were studied before and in the 1st, 3rd, 7th, 14th and 28th days after the transplantation. RESULTS: The GSH-Px, SOD, ECu, EZn and selenium levels were lower and MDA levels were higher in patients than controls before transplantation (p < 0.001 for all). MDA levels decreased and SOD, GSH-Px, ECu, EZn levels increased in parallel to the decrement of serum creatinine levels following the renal transplantation. No difference was found among the patients regarding the treatment regime. CONCLUSION: The study data suggest that the improvement in oxidative state parameters begins at the first day of renal transplantation and continues at the 28th posttransplant day in living donor transplantations.

Adult↗

PubMed2005

Blockade of the renin-angiotensin system increases plasma adiponectin levels in type-2 diabetic patients with proteinuria.

BACKGROUND/AIMS: Adiponectin seems to be an important modulator for metabolic and vascular diseases. A case study was designed to measure plasma adiponectin levels and to investigate the effects of angiotensin-converting enzyme inhibitors on adiponectin levels in type-2 diabetic patients with proteinuria. METHODS: Forty-nine patients (28 males, 21 females) and 23 healthy volunteers (13 males, 10 females) were included in the case study. Patients with proteinuria were treated with 5 mg/day ramipril (n = 21) for 4 weeks. RESULTS: Adiponectin levels of patients were significantly lower than those of healthy volunteers (p < 0.001). There were significant negative correlations between adiponectin concentrations and insulin levels as well as the homeostasis model assessment (HOMA) index in the patient group (r = -0.655, p < 0.001; r = -0.469, p = 0.001, respectively). There was also a significant negative correlation between plasma adiponectin concentrations and the degree of proteinuria (r = -0.912, p < 0.001). Plasma adiponectin levels in patients with proteinuria (n = 21; 4.81 +/- 3.17 microg/ml) were significantly lower than those without proteinuria (n = 28; 10.25 +/- 2.03 microg/ml; p < 0.001). After the treatment period, adiponectin levels significantly increased (p < 0.001) and proteinuria, plasma insulin, and HOMA indexes significantly decreased in the treatment group (p < 0.001, p < 0.001, p = 0.002, respectively). CONCLUSIONS: The results suggest that adiponectin is inversely correlated with proteinuria and treatment with ramipril both corrects proteinuria and increases the low adiponectin levels in diabetic patients.

Adiponectin↗

PubMed2004

Peroxisome proliferator-activated receptor gamma (PPAR-gamma) agonist increases plasma adiponectin levels in type 2 diabetic patients with proteinuria.

Adiponectin appears to be an important modulator for metabolic and vascular diseases. A case-controlled study was designed to measure plasma adiponectin levels and investigate the effects of rosiglitazone on adiponectin levels in type 2 diabetic patients with proteinuria. Sixty-four patients (mean age, 46.1+/-4.6 yr; 30 male, 34 female) and 26 healthy volunteers (mean age, 45.3+/-4.8 yr; 14 male, 12 female) were included. Patients with proteinuria were treated with 4-mg/d rosiglitazone (n=21, 10 males, 11 females) for 4 wk. Adiponectin levels in patients were significantly lower than those of controls (p<0.001). There were significant negative correlations between adiponectin concentrations and insulin levels as well as homeostasis model assessment (HOMA) index in patient's group (r=- 0.538, p<0.001; r=- 0.393, p=0.001, respectively). There was also a significant negative correlation between plasma adiponectin concentrations and the degree of proteinuria (r=- 0.526, p=0.002). Plasma adiponectin levels in patients with proteinuria (n=31; 3.91+/-2.57 microg/mL) were significantly lower than those without proteinuria (n=33; 10.15+/-1.97 microg/mL) (p<0.001). After the treatment period, adiponectin levels significantly increased (p<0.001) and proteinuria, plasma insulin, and HOMA indexes significantly decreased in treatment group (p<0.001, p<0.001, p<0.001, respectively). The results suggest that adiponectin is inversely correlated with proteinuria and treatment with peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonist rosiglitazone both corrects proteinuria and increases the low adiponectin levels in diabetic patients.

Adipocytes↗