Gülcan Güntaş Korkmaz

The association of oxidative stress markers with conventional risk factors in the metabolic syndrome

BACKGROUND AND AIMS The metabolic syndrome (MetS) is a common and complex disorder that consists of various abnormalities, including dyslipidemia, obesity, hypertension and hyperglycemia. We investigated the relationships between the levels of advanced protein oxidation products (AOPPs), the total antioxidant capacity (TAC) and the pro-oxidant-antioxidant balance (PAB) in MetS patients. METHODS A total of 55 patients (37 women, 18 men) with MetS and 20 healthy controls (14 women, 6 men) with a body mass index (BMI) less than 25 kg/m(2) were enrolled in the study. Colorimetric methods were used to determine the levels of AOPPs, the TAC, and the PAB. RESULTS AOPP, TAC, and PAB values were significantly higher in patients with MetS than in control subjects (p<0.001, p=0.050, and p<0.001, respectively). A positive correlation was observed between the AOPP levels and the glucose, triglyceride, insulin and HOMA-IR levels. PAB values also exhibited significant positive correlations with diastolic blood pressure and fibrinogen levels. Logistic regression analysis revealed that higher serum PAB values were positively and independently associated with the MetS (odds ratio: 1.110; 95% confidence interval: 1.006-1.224; P<0.37). CONCLUSIONS Increased AOPP levels and higher PAB values are likely to be a result of oxidative stress, a condition in which an imbalance occurs between the production and inactivation of reactive oxygen species. In addition, it appears that serum PAB values may accurately reflect the levels of oxidative stress in MetS patients.

Oxidative damage parameters in renal tissues of aged and young rats based on gender

Purpose Aging is characterized by a gradual functional decrease of all systems including the kidneys. Growing evidence links altered lipid protein redox-homeostasis with renal dysfunction. The effect of sexual dimorphism on the lipid protein redox-homeostasis mechanisms in the aging kidney is obscure. In the current study, we aimed to investigate redox homeostasis as it related to sexual dimorphism on protein oxidation and lipid peroxidation parameters, as protein carbonyl (PCO), total thiol (T-SH), advanced oxidation protein products (AOPP), malondialdehyde, glutathione (GSH), and superoxide dismutase (SOD) activity, as potential aging biomarkers, which may contribute to an analysis of the free radical theory of aging. Materials and methods The study was carried out with 16 naturally aged rats (24 months old; eight males and eight females) and their corresponding young rat groups as controls (6 months old; eight males and eight females). All of the aforementioned parameters (PCO, T-SH, AOPP, MDA, GSH, SOD) were measured manually instead of automated devices or ELISA kits. Results PCO, AOPP, and malondialdehyde levels in aged rats were significantly higher in the older rat group than in the younger rat group, whereas SOD activities were significantly lower in old rats. T-SH levels were not significantly different in male groups; however, T-SH levels were lower in the aged female group than in the young female control group. In addition, GSH levels were significantly different between the aged rat group and the corresponding young control group for both genders. Conclusion With respect to PCO and AOPP, impaired redox homeostasis is substantially more prominent in males than females. The decrease of G-SH levels in male groups could be attributed to stabilizing the redox status of protein thiol groups by the depletion of the GSH groups. Considering the results, the renal tissue proteins and lipids in different genders may have different susceptibilities to oxidative damage.

Total antioxidant status and markers of oxidative stress in subjects with normal or impaired glucose regulation (IFG, IGT) in diabetic patients

Abstract Background. We investigated the ischemia-modified albumin (IMA), advanced oxidation protein products (AOPPs), prooxidants–antioxidants balance (PAB), and ferric reducing antioxidant power (FRAP) concentrations in patients with impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and diabetes mellitus (DM) and compared the results to those of normoglycemic individuals at baseline and 2 hours after glucose loading. Methods. An oral glucose tolerance test was performed on age-matched subjects (n = 110) with a body mass index (BMI) < 27 kg/m2. Subjects were categorized as normoglycemic (n = 35), IFG (n = 25), IGT (n = 30) and DM (n = 20) according to the WHO criteria. The IMA, AOPP, PAB, FRAP concentrations were determined by colorimetric methods. Results. At baseline, the AOPP concentrations were significantly higher in subjects with IFG and DM compared to normoglycemic subjects (p < 0.01 for all cases). The IFG, IGT and DM patients had a significantly higher IMA at baseline when compared with the normoglycemic individuals (p < 0.001 for all cases). The IMA in IFG subjects was significantly elevated (p < 0.05), while in DM patients, the IMA was significantly decreased (p < 0.001) after glucose loading with respect to baseline concentrations. Following glucose loading, the PAB was significantly decreased from baseline concentrations in normoglycemic individuals (p < 0.001) and in the IFG (p < 0.001) and IGT (p < 0.001) patients. Conclusion. In subjects with impaired glucose metabolism, the hyperglycemia is associated with increased IMA, AOPP and PAB concentrations. Increased IMA in subjects with IFG and decreased FRAP concentrations in subjects with IGT after glucose loading suggests that an increase in glucose concentrations can lead to tissue damage by increasing oxidative stress.

The role of pentraxin 3 as diagnostic value in classification of patients with heart failure

OBJECTIVE Pentraxin 3 (PTX3) is a new inflammatory marker that is the prototype of the long pentraxin group, while C-reactive protein (CRP) is the short pentraxin group. The aim of the present study was to investigate the clinical significance of plasma PTX3 and CRP levels in heart failure (HF). MATERIALS AND METHODS The study included 22 male and 37 female patients with HF, and 23 healthy volunteers as the control group. Patients were divided into 4 groups (class I, II, III and IV) according to New York Heart Association functional class. RESULTS Plasma PTX3 and CRP levels were significantly elevated in HF patients compared to healthy controls. Comparing PTX3 levels in patient groups, statistically significant difference was found between class-I and class-II, class-III and class-IV patients (p=0.009, p=0.001, p<0.001, respectively). There was a positive correlation between PTX3 and CRP levels (r=0.369, p=0.004). In receiver-operating characteristic (ROC) curves, area under the curve (AUC) values for PTX3 and CRP were 0.928 (p=0.001) and 0.834 (p=0.001), respectively. CONCLUSIONS Plasma PTX3 levels are elevated in HF and might be used as diagnostic value in classification of patients with HF. It is still debated whether inflammation may be just a cause or a consequence of the disease. Therefore further work is needed to better understand in large populations of patients with HF.

The role of feed regulating peptides on weight loss in patients with pulmonary tuberculosis.

PURPOSE Malnutrition is a prominent feature of tuberculosis (TB). The aim of our study was to explore the function of plasma regulatory proteins in pulmonary TB and to investigate the relationship between these parameters and loss of body weight. METHODS Plasma levels of fasting insulin, leptin, ghrelin, adiponectin and orexin-A were measured in 23 pulmonary TB patients, 39 patients with pulmonary sarcoidosis, 22 patients with different diffuse interstitial lung diseases and 21 healthy patients serving as controls. RESULT Plasma leptin (p<0.001) and orexin-A (p<0.01) levels were significantly decreased in TB patients compared with those of the other study subjects. TB patients also had higher levels of plasma ghrelin compared with those of the other study subjects, while sarcoidosis patients had higher plasma adiponectin levels than the other study subjects. Glucose levels were similar in all groups, yet, insulin and Homeostasis Model of Assessment-Insulin Resistance (HOMA-IR) levels were significantly higher in the TB group compared to the other study groups. There was no correlation between leptin, ghrelin, adiponectin and orexin-A and other parameters. CONCLUSIONS These data suggest that leptin and orexin-A levels have effects on weight loss in patients with pulmonary tuberculosis. Particularly, leptin may play a role in the early immune response to pulmonary TB and prolonged inflammation may further suppress leptin production. Measurement of HOMA-IR can indeed be used as a marker for the risk of activated TB. Further clinical studies are needed to better understand the role of feed regulating proteins in pulmonary tuberculosis.