Yusuf Turkoz

Serum levels of TNF-alpha, sIL-2R, IL-6, and IL-8 are increased and associated with elevated lipid peroxidation in patients with Behçet's disease.

AIM: Behçets disease (BD) is asystemic immunoinflammatory disorder and the aetiopathogenesis is to be specified. Cytokines play a role in immune response and in many inflammatory diseases. The aim of this case-control study is to investigate serum pro-inflammatory cytokine tumour necrosis factor (TNF)-alpha, interleukin-1beta (IL-1beta), soluble IL-2 receptor (sIL-2R), IL-6, and chemokine IL-8 levels in patients with BD. We also determined the end product of lipid peroxidation (malondialdehyde (MDA)) in BD patients as an index for oxidative stress. METHODS: A total of 37 patients (19 men, 18 women) with BD (active, n = 17; inactive, n = 20) and 20 age-matched and sex-matched healthy control subjects (11 men, nine women) included in this cross-sectional, blinded study. Serum TNF-alpha, IL-1beta, sIL-2R, IL-6 and IL-8 levels were determined by a spectrophotometer technique using the immulite chemiluminescent immunometric assay. Lipid peroxidation was evaluated by Wasowicz et aL The levels of cytokines and lipid peroxidation in the active period were compared with the inactive period of the disease. Results are expressed as mean +/- standard error. RESULTS: IL-1beta levels were below the detection limits of the assay (< 5 pg/ml) in all samples. Mean levels of MDA (8.1+/-0.7 micromol/l), sIL-2R (800+/-38 U/ml), IL-6 (12.6+/-1.1 pg/ml), IL-8 (7.2+/-0.4 pg/ml), and TNF-alpha (7.9+/-0.5 pg/ml) in active BD patients were significantly higher than those in inactive patients (4.3+/-0.5 micromol/l, p < 0.01; 447+/-16 U/ml, p < 0.001; 8.3+/-0.6 pg/ml, p = 0.006; 5.3+/-0.1 pg/ml, p < 0.001; and 5.1 0.2 pg/ml, p < 0.001; respectively) or control subjects (2.1+/-0.2 micromol/l, p < 0.001; 446+/-20 U/ml, p < 0.001; 6.4+/-0.2 pg/ml, p < 0.001; 5.4+/-0.1 pg/ml, p < 0.001; and 4.7+/-0.1 pg/ml, p < 0.001, respectively). On the contrary, only the mean IL-6 level was significantly different between inactive BD and control subjects (p = 0.02). All acute phase reactants were significantly higher in active BD than in inactive period (for each, p < 0.01). Conclusions: High levels of sIL-2R, IL-6, IL-8 and TNF-alpha indicate the activation of immune system in BD. Serum sIL-2R, IL-6, IL-8 and TNF-alpha seem to be related to disease activity. Increased lipid peroxidation suggests oxidative stress in BD and therefore tissue damage in such patients. Amelioration of clinical manifestations would be envisaged by targeting these cytokines, chemokines and lipid peroxidation with pharmacological agents.

Central nervous system protection by resveratrol in streptozotocin-induced diabetic rats

The objective of the present study was to investigate the possible neuroprotective effect of resveratrol against streptozotocin-induced hyperglycaemia in the rat brain and medulla spinalis. Thirty adult male Wistar rats were divided into three groups as follows: control group, streptozotocin-induced diabetic-untreated group, and streptozotocin-induced diabetic resveratrol-treated group. Diabetes was induced by a single injection of streptozotocin (STZ) (60 mg/kg body weight). Three days after streptozotocin injection, resveratrol (10 mg/kg) was injected intraperiteonally daily over 6 weeks to the rats in the treatment group. Six weeks later, seven rats from each group were killed and the brain stem and cervical spinal cord were removed. The hippocampus, cortex, cerebellum, brain stem and spinal cord were dissected for biochemical studies (lipid peroxidation measuring malondialdehyde [MDA], xanthine oxidase [XO], nitric oxide [NO] and glutathione). MDA, XO and NO levels in hippocampus, cortex, cerebellum, brain stem and spinal cord in the streptozotocin-induced diabetic-untreated group increased significantly. Treatment with resveratrol significantly reduced MDA, XO and NO production and increased glutathione levels when compared to the streptozotocin-induced diabetic-untreated group. This study demonstrates that resveratrol is a potent neuroprotective agent against diabetic oxidative damage.

Increased Nitric Oxide Production in the Spermatic Vein of Patients with Varicocele

Objective: To define the level of nitric oxide (NO) in the spermatic vein of patients with varicocele and its relation with male infertility.Materials and Methods: Following physical and color Doppler ultrasonographic examination, whole blood samples were drawn from a peripheral vein and a dilated varicocele vein from fourteen patients with clinically palpable varicocele (G2–3) before ligation. NO levels in the serum were determined as total nitrite by Greiss reaction and results were compared with Mann–Whitney U test.Results: NO levels in the internal spermatic vein were 36.05 ± 8.92 μmol/l, compared to 19.41 ± 4.12 μmol/l in the peripheral vein and the difference was statistically significant (p < 0.01).Conclusion: In view of our results, increased NO levels in the dilated varicocele vein might be responsible for spermatozoa dysfunction.

Nitric oxide and lipid peroxidation are increased and associated with decreased antioxidant enzyme activities in patients with age-related macular degeneration

Background: Nitric oxide (NO), hydroxyl radical (OH.), superoxide anion (O2−) and hydrogen peroxide (H2O2) are free-radicals released in oxidative stress. Superoxide dismutase (SOD), glutathione peroxidase (GSHPx) and catalase (CAT) are antioxidant enzymes, mediating defense against oxidative stress. Excess NO and/or defective antioxidants cause lipid peroxidation, cellular dysfunction and death. Age-related maculopathy (ARM) or degeneration (ARMD) is the leading cause of irreversible blindness in developed countries. The etiology is unclear and the molecular factors contributing this disease remain to be specified. Aims: This multicenter, double-blind, cross-sectional study aimed to investigate plasma NO and lipid peroxidation levels with relation to antioxidant enzyme activities in erythrocyte and plasma of patients with ARMD compared with healthy control subjects. Methods: NO, lipid peroxidation (measured as plasma malondialdehyde [MDA] levels) and the catalytic activity of SOD, GSHPx and CAT were measured in a group of 41 patients with maculopathy (19 men, 22 women; 67.12 ± 3.70 years) and compared with 25 age- and sex-matched healthy control subjects without maculopathy (12 men, 13 women; 68.04 ± 3.02 years). NO and MDA levels were measured in plasma, CAT in red blood cells (RBCs), and SOD and GSHPx in both plasma and RBCs. Color fundus photographs were used to assess the presence of maculopathy, and the patients were divided into two groups using clinical examination and grading of photographs; early-ARM (n = 22) and late-ARMD (n = 19). Results: All patients with maculopathy had significantly (p<0.001) higher plasma NO levels over control subjects (mean ± SD, 48.58 ± 8.81 vs. 28.22 ± 3.39 μmol/l). Plasma MDA levels in patients and control subjects were 4.99 ± 1.00 and 2.16 ± 0.24 μmol/l, respectively, and the difference was significant (p<0.001). On the other hand, SOD and GSHPx activities were significantly lower in both RBCs and plasma of patients with maculopathy than in control subjects (RBCs-SOD, 3509.30 ± 478.22 vs. 5033.30 ± 363.98 U/g Hb, p<0.001; plasma-SOD, 560.95 ± 52.52 vs. 704.76 ± 24.59 U/g protein, p<.001; RBCs-GSHPx, 663.43 ± 41.74 vs. 748.80 ± 25.50 U/g Hb, p<0.001; plasma-GSHPx, 98.26 ± 15.67 vs. 131.80 ± 8.73 U/g protein, p<0.001). RBCs-CAT levels were not different between groups (131.68 ± 12.89 vs. 133.00 ± 13.29 k/g Hb, p=0.811). Late-ARMD patients had significantly lower antioxidant enzyme levels and higher MDA levels when compared with early-ARM patients (for each, p<0.001). In addition, plasma NO and MDA levels were negatively correlated with SOD and GSHPx activities. Conclusions: This study demonstrated for the first time that NO, the most abundant free-radical in the body, might be implicated in the pathophysiology of ARMD in association with decreased antioxidant enzymes and increased lipid peroxidation status.

Vascular endothelial growth factor levels are increased and associated with disease activity in patients with Behçet's syndrome.

Background/aims  Vascular endothelial growth factor (VEGF) is a cytokine participating in inflammation with potent endothelial cell effects. It is produced by macrophages, neutrophils and vascular endothelial cells and can alter vessel permeability. Behçets syndrome is a systemic inflammatory disorder with unknown etiology. Vascular endothelial dysfunction is one of the prominent features of the disease. We previously demonstrated the possible involvement of proinflammatory cytokines [tumor necrosis factor (TNF)‐α, soluble interleukin‐2 receptor (sIL‐2R), interleukin (IL)‐6 and IL‐8], nitric oxide (NO) and adrenomedullin in the etiopathogenesis of Behçets syndrome. Since VEGF expression is induced by these cytokines and VEGF itself is a potent stimulator of NO production with endothelial cell effects, this study aimed to investigate whether VEGF was affected during the course of Behçets syndrome. We also assessed the possible involvement of VEGF in ocular Behçets syndrome or in disease activity.

Serum homocysteine level is increased and correlated with endothelin-1 and nitric oxide in Behçet's disease.

Background/aims: Behçets disease (BD) is a systemic inflammatory vasculitis of young adults with unknown aetiology, characterised by endothelial dysfunction and occlusion in both deep venous and retinal circulation. Ocular involvement occurs in 70% of cases and is characterised by periphlebitis, periarteritis, vascular occlusion, and thrombosis leading to blindness despite vigorous treatment. Endothelin-1 (ET-1) is a vasoconstricting peptide while nitric oxide (NO) is a relaxing molecule and both are released by endothelium for blood flow regulation. Homocysteinaemia is a newly defined term connected to the increased risk of atherothrombotic and atherosclerotic systemic and retinal vascular occlusive diseases, and its role in the course of BD has not been previously described. The authors aimed to detect serum total homocysteine (tHcy), ET-1, and NO in BD and to assess if tHcy, ET-1, and NO are associated with ocular BD or disease activity. Methods: 43 consecutive patients with ocular (n = 27) or non-ocular (n = 16) BD (36.95 (SD 9.80) years, 22 male, 21 female) satisfying international criteria, and 25 age and sex matched healthy control subjects (37.88 (8.73) years, 13 male, 12 female) without a history of systemic or retinal venous thrombosis were included in this study. Patients were examined by two ophthalmologists with an interest in BD. Serum tHcy, ET-1, and NO concentrations were measured in both groups. Hyperhomocysteinaemia was defined as a tHcy level above the 95th percentile in the control group. Patients were divided into active and inactive period by acute phase reactants including α1 antitrypsin, α2 macroglobulin, erythrocyte sedimentation rate, and neutrophil count. Results: The overall mean serum tHcy, ET-1, and NO levels were significantly higher in patients with BD than in control subjects (tHcy = 15.83 (4.44) v 7.96 (2.66) ng/ml, p <0.001; ET-1 = 17.47 (4.33) v 5.74 (2.34) μmol/ml, p <0.001; NO = 37.60 (10.31) v 27.08 (7.76) μmol/l, p <0.001). Serum tHcy, ET-1, and NO levels were significantly higher in active patients than in inactive patients and control subjects. In addition, among patients with ocular BD, the mean tHcy levels were significantly increased and correlated with ET-1 and NO levels when compared with non-ocular disease and control subjects. All acute phase reactant levels were significantly higher in active period than in inactive stage and controls. Conclusions: Elevated tHcy may be responsible for the endothelial damage in BD and may be an additional risk factor for the development of retinal vascular occlusive disease, contributing to the poor visual outcome in these patients. Assessment of tHcy may be important in the investigation and management of patients with BD, especially with ocular disease.

Comparative neuroprotective effect of sodium channel blockers after experimental spinal cord injury.

Spinal cord injury (SCI) results in loss of function below the lesion. Secondary injury following the primary impact includes a number of biochemical and cellular alterations leading to tissue necrosis and cell death. Influx of Na(+) ions into cells has been postulated to be a key early event in the pathogenesis of secondary traumatic and ischemic central nervous system injury. Previous studies have shown that some voltage-sensitive sodium channel blockers provide powerful neuroprotection. The purpose of the present study was to compare the neuroprotective effect of three sodium channel blockers-mexiletine, phenytoin and riluzole--after SCI. Ninety rats were randomly and blindly divided into five groups of 18 rats each: sham-operated group, trauma group (bolus injection of 1 mL physiological saline intraperiteonally [i.p.]), mexiletine treatment group (80 mg/kg, i.p.), phenytoin treatment group (200 mg/kg, i.p.) and riluzole treatment group (8 mg/kg, i.p.). Twenty-four hours after injury, the rats were killed for determination of spinal cord water content and malondialdehyde (MDA) levels. Motor function scores of six rats from each group were evaluated weekly for six weeks. Then the rats were killed for histopathological assessment. Although all the treatment groups revealed significantly lower MDA levels and spinal cord edema than the trauma group (p<0.05), the riluzole and mexiletine treatment groups were better than the phenytoin treatment group. In the chronic stage, riluzole and mexiletine treatment achieved better results for neurobehavioral and histopathological recovery than phenytoin treatment. In conclusion, all the tested Na(+) blockers had a neuroprotective effect after SCI; riluzole and mexiletine were superior to phenytoin.

Decreased nitric oxide production in primary open-angle glaucoma

Purpose Raised intraocular pressure (IOP) is the major risk factor responsible for optic nerve damage in primary open-angle glaucoma (POAG). The trabecular meshwork acts as a valve in aqueous outflow and relaxes with nitric oxide (NO) agonists. Since NO is synthesized by endothelium and smooth muscle elsewhere in the body, this study investigated the NO levels in the aqueous humor of patients with POAG compared with cataract patients. Materials and Methods Aqueous humor samples were taken by paracentesis from 16 consecutive patients with POAG (9 male and 7 female; mean age 69.0 ± 3.4 yrs) and 14 age and sex-matched controls with cataract (8 male and 6 female; mean age 66.7 ± 4.1 yrs) during elective surgery. As an indicator for NO, aqueous total nitrite levels (end - product of NO) were measured by Greiss reaction. The Mann-Whitney U test was used for statistical analysis and P <0.05 was considered significant. Results The mean age and sex in two groups were comparable. The mean aqueous humor NO levels were significantly (P = 0.001) lower in patients with glaucoma (72.72 ± 11.21 μmol/L) than in patients with cataract and no glaucoma (86.92 ± 11.23 μmol/L). Conclusions Decreased NO production in patients with POAG indicates that NO-producing cells may be lost as the disease progresses. The control of NO levels in the eye might be a therapeutic target in glaucoma.

Effects of resveratrol and methylprednisolone on biochemical, neurobehavioral and histopathological recovery after experimental spinal cord injury

AbstractAim:To investigate the neuroprotective effect of resveratrol in an experimental spinal cord injury (SCI) model in rats.Methods:Male Wistar albino rats weighing 200–250 g were randomized into six groups. Weight-drop trauma was performed for SCI. Group 1 underwent laminectomy alone. Group 2 underwent laminectomy followed by SCI. Groups 3, 4, 5, and 6 underwent laminectomy followed by SCI and received resveratrol (100 mg/kg), methylprednisolone (MP) (30 mg/kg), resveratrol (100 mg/kg) plus MP (30 mg/kg), and ethanol (2%), respectively. The rats were divided into two subgroups for biochemical analysis (killed at 24 h after surgery) and for neurobehavioral and histopathological evaluation (killed at 6 weeks after surgery). Posttraumatic neurological recovery after surgery was recorded weekly.Results:Groups 3 and 5 revealed significantly lower malondialdehyde, nitric oxide, xanthine oxidase, and higher glutathione levels than group 4 (P<0.05). Neurological recovery rates were significantly better in groups 3 and 5 than group 4 (P<0.05). When spinal trauma size ratios were compared, there was no significant difference between treatment groups.Conclusion:Resveratrol treatment revealed better biochemical recovery in the acute stage of trauma than MP treatment. Although resveratrol and combined treatment revealed better neurobehavioral recovery than MP treatment; resveratrol, MP, and combined treatment modalities improved histopathological recovery at the same level in the final stage of the experiment. Future studies involving different doses of resveratrol and different doses combinations with MP could promise better results as each drug has a different anti-oxidative mechanism of action.

The attenuation of vasospasm by using a sod mimetic after experimental subarachnoidal haemorrhage in rats.

Background. Delayed cerebral vasoconstriction and brain ischemia, are critical problems in the management of a patient affected by rupture of an intracranial aneurysm. Overexpression of Cu–Zn superoxide dismutase (Cu–Zn SOD) can reduce the extent of cerebral vasospasm. We, therefore investigated if vasospasm, can be prevented by a novel, stable, and cell permeable SOD mimetic, MnTBAP [Mn(III) tetrakis (4-benzoic acid) porphyrin] which permeates the biological membranes and scavenges superoxide anions and peroxynitrite.Methods. 28 rats (225–250 g) were divided equally into four groups: group 1: control; group 2: SAH only; group 3: SAH plus placebo; and group 4: SAH plus MnTBAP. We used a double haemorrhage method to produce SAH. Starting six hours after SAH, 5 mg/kg MnTBAP (Calbiochem, Darmstadt-Germany; Cat. No 475870)) or an equal volume of 0.9% saline (37 °C) was administered by intraperitoneal injection twice daily for 5 days to groups 4 and 3 respectively. MnTBAP or 0.9% saline injections were continued up to fifth day after SAH and rats were sacrificied on the fifth day. Brain sections at the level of the pons were examined by light microscopy. Planimetric measurements were made for the cross-sectional areas of the lumen and the vessel wall (intima plus media) of the basilar artery by a micrometer.Finding. Administration of MnTBAP significantly attenuated the vasoconstriction of the basilar artery in group 4 compared with the groups 2 and 3 (p<0.001).Interpretation. These results suggest that this SOD mimetic (MnTBAP) attenuates delayed cerebral vasoconstriction following experimental SAH and that superoxide anions have a role in the pathogenesis of vasospasm after SAH.