Decreased Activity of Erythrocyte Catalase and Glutathione Peroxidase in Patients with Schizophrenia.

Background and Objectives: Catalase and glutathione peroxidase (GPx) are important antioxidant enzymes that break down hydrogen peroxide (H2O2) in order to control its intracellular concentration, thus enabling its physiological role and preventing toxic effects. A lack or disruption of their function leads to the accumulation of hydrogen peroxide and the occurrence of oxidative stress. Accumulating studies have shown that the activities of key antioxidant enzymes are impaired in patients with schizophrenia. Since the published results are contradictory, and our previous studies found significantly higher erythrocyte superoxide dismutase (SOD) activity in patients with schizophrenia, the aim of this study was to determine the activity of enzymes that degrade hydrogen peroxide in the same group of patients, as well as to examine their dependence on clinical symptoms, therapy, and parameters associated with this disease. Materials and Methods: Catalase and GPx activities were determined in the erythrocytes of 68 inpatients with schizophrenia and 59 age- and gender-matched healthy controls. The clinical assessment of patients was performed by using the Positive and Negative Syndrome Scale (PANSS). The catalase activity was measured by the kinetic spectrophotometric method, while the GPx activity was determined by the commercially available Ransel test. Results: Erythrocyte catalase and GPx activities were significantly lower (p < 0.001 and p < 0.01, respectively) in subjects with schizophrenia than they were in healthy individuals. Lower catalase activity does not depend on heredity, disease onset, the number of episodes, or disease duration, while GPx activity showed significant changes in patients who had more than one episode and in those who had been suffering from the disease for over a year. Significantly lower catalase activity was noted in the PANSS(+/−) group in comparison with the PANSS(+) and PANSS(−) groups. The lowest catalase activity was found in subjects who were simultaneously treated with first- and second-generation antipsychotics; this was significantly lower than it was in those who received only one class of antipsychotics. Conclusion: These results indicate the presence of oxidative stress in the first years of clinically manifested schizophrenia and its dependence on the number of psychotic episodes, illness duration, predominant symptomatology, and antipsychotic medication.

Diagnostic Accuracy of Brain-derived Neurotrophic Factor and Nitric Oxide in Patients with Schizophrenia: A pilot study.

BACKGROUND: Brain-derived neurotrophic factor (BDNF) and nitric oxide (NO) play multiple roles in the developing and adult CNS. Since BDNF and NO metabolisms are dysregulated in schizophrenia, we measured these markers simultaneously in the blood of schizophrenics and assessed their diagnostic accuracy. METHODS: Thirty-eight patients with schizophrenia classified according to demographic characteristics, symptomatologyand therapy and 39 age- and gender-matched healthy controls were enrolled. BDNF was determined by the ELISA technique while the concentration of nitrite/nitrate ([Formula: see text]) was measured by the colorimetric method. RESULTS: Serum BDNF levels were significantly lower (20.38±3.73 ng/mL, P = 1.339E-05), whilst plasma [Formula: see text] concentrations were significantly higher (84.3 (72-121) µmol/L, P=4.357E-08) in patients with schizophrenia than in healthy controls (25.65±4.32 ng/mL; 60.9 (50-76) µmol/L, respectively). The lowest value of BDNF (18.14±3.26 ng/mL) and the highest [Formula: see text] concentration (115.3 (80-138) µmol/L) were found in patients treated with second-generation antipsychotics (SGA). The patients diseased before the age of 24 and the patients suffering for up to one year had significantly lower serum BDNF levels than those diseased after the age of 24 and the patients who were ill longer than one year. Both BDNF and [Formula: see text] showed good diagnostic accuracy, but BDNF had better ROC curve characteristics, especially in patients with negative symptomatology. CONCLUSIONS: BDNF and nitrite/nitrate showed inverse changes in schizophrenic patients. The most pronounced changes were found in patients treated with second-generation antipsychotics. Although BDNF is not specific of schizophrenia, it may be a clinically useful biomarker for the diagnosis of patients expressing predominantly negative symptoms.

Influence of dialysis modality and membrane flux on insomnia severity in haemodialysis patients.

AIM: Insomnia is an important problem in dialysis patients. A greater prevalence of insomnia in chronic kidney disease compared with non-renal patients suggests a role for uraemic toxins in contributing to insomnia. The aim of this study was to examine if dialysis modality and membrane permeability is associated with the frequency and severity of insomnia in haemodialysis patients. METHODS: In our cross-sectional study, we evaluated 122 patients who were divided into three groups: on-line haemodiafiltration, high flux haemodialysis and low flux haemodialysis. The frequency and severity of insomnia was evaluated with the Insomnia Severity Index. RESULTS: Insomnia was present in 47.5% of all patients. The majority of patients who reported insomnia were receiving low flux haemodialysis (80%), followed by patients on high flux haemodialysis (43.6%) and haemodiafiltration (20.9%). Patients using low flux membranes, had a significantly higher Insomnia Severity Index (11.9 ± 6.6) compared with patients receiving high flux haemodialysis (6.8 ± 6.3) and haemodiafiltration (5.2 ± 7.0). The insomnia severity index did not differ between patients receiving high flux haemodialysis compared with on-line haemodiafiltration. CONCLUSION: This study indicates that different haemodialysis modalities are associated with insomnia and suggests a potential benefit of using high flux membranes.

Schizophrenia is associated with increased levels of serum Fas and FasL.

BACKGROUND: A growing body of evidence suggests that the apoptotic process is dysregulated in schizophrenia. However, only a few studies have evaluated apoptotic markers in vivo in patients or their cell cultures. METHODS: Serum concentrations of Fas receptor (Fas/APO-1) and Fas ligand (FasL) were measured by ELISA techniques. The differences were tested according to the patients' demographic, clinical and drug treatment characteristics. The clinical accuracy of the examined markers was assessed using receiver operating characteristic (ROC) curve analysis. RESULTS: In this case-controlled study both sFas/APO-1 and FasL were significantly higher in the patients with schizophrenia than in the controls. An increase in apoptotic markers was independent of the symptomatology, drug treatment, heredity, the first onset of the disease, the duration of the psychotic disease as well as the tobacco abuse. A significant negative correlation between the duration of the disease and sFasL concentration was found. At the same time, a significant positive correlation was found between sFasL and lymphocyte caspase-3 activity. ROC curve analysis showed that sFasL was the most strongly associated with the presence of schizophrenia. CONCLUSIONS: We can conclude that the extrinsic apoptotic pathway is dysregulated in schizophrenia and sFasL may be a clinically useful disease predictor.

Influence of dialysis modality and membrane flux on quality of life in hemodialysis patients.

BACKGROUND: The quality of life in patients undergoing hemodialysis is significantly disturbed. There are data that hemodiafiltration (HDF) may be more effective than conventional hemodialysis in the removal of uremic toxins and may reduce frequency and severity of intradialytic and postdialysis adverse symptoms in patients. Also, some researchers suggest advantages of using high-flux membranes compared with low-flux. OBJECTIVE: The aim of this study was to examine whether hemodialysis modality and membrane flux, independent of membrane biocompatibility, make differences in quality of life in patients. METHODS: In our cross-sectional study, we evaluated 124 patients who were divided, based on therapy, into three groups: online HDF, high-flux hemodialysis, and low-flux hemodialysis. Data were collected using the Short Form-36 questionnaire combined with special questionnaire, which included demographic and clinically related questions. RESULTS: Health-related quality of life was better in patients on HDF compared with patients on hemodialysis, especially compared with low-flux hemodialysis patients in most of the scales and in both dimensions: physical component scale and mental component scale. There were no statistically significant differences in Short Form-36 domains between high-flux hemodialysis and low-flux hemodialysis. CONCLUSION: Our data suggest the potential advantages of HDF with regard to influence on quality of life, which is sufficient to justify further research in prospective and longitudinal study design.

Plasma nitrite/nitrate concentrations in patients with schizophrenia.

BACKGROUND: Nitric oxide (NO) is known to be a signaling molecule with many physiogical functions including apoptotic process regulation. Since apoptosis may contribute to the pathophysiology of schizophrenia, this study was undertaken to determine the plasma concentrations of NO in schizophrenics. METHODS: Nitrite/nitrate (NO(2)(-)/NO(3)(-)) concentrations were measured in plasma from 40 patients with schizophrenia, and 36 age- and gender-matched healthy persons using a colorimetric test. RESULTS: Plasma NO(2)(-)/NO(3)(-) concentrations were significantly higher in patients with schizophrenia (102.8+/-34.7 micromol/L, p<0.0001) than in controls (69.2+/-13.2 micromol/L). Also, mean NO(2)(-)/NO(3)(-) values in female patients and controls were significantly higher (118.2+/-44.7 micromol/L, p<0.001; 74.8+/-16.1 micromol/L, p<0.05, respectively) compared to males (94.7+/-25.3 micromol/L, 67.6+/-10.8 micromol/L). Significant correlation was seen between plasma NO(2)(-)/NO(3)(-) concentrations and heredity, number of episodes and peripheral blood mononuclear cell (PBMC) caspase-3 activity, which was significantly higher in patients than in controls (p<0.05). There was no significant difference in NO(2)(-)/NO(3)(-) concentrations between patients with different Positive and Negative Syndrome Scale (PANSS) scores or between patients treated with haloperidol (97.2+/-31.2 micromol/L) and those treated with other atypical antipsychotic drugs (109.8+/-33.7 micromol/L). Both parameters showed no significant differences between smokers and non-smokers. CONCLUSIONS: This study showed that plasma NO(2)(-)/NO(3)(-) concentrations were significantly increased in patients with schizophrenia, being significantly higher in female than male patients, and showing a significant correlation with heredity, number of episodes and PBMC caspase-3 activity. These results suggest that NO could be considered an inducer or regulator of apoptosis in patients with schizophrenia.