Platelet Enzymes of Glutathione Metabolism in Patients with Late-Onset Schizophrenic Spectrum Disorders

Abstract

Background: basing on the hypothesis that oxidative stress participates in schizophrenia pathogenesis, the authors suggested that the activities of glutathione reductase (GR) and glutathione-S-transferase (GST), the enzymes metabolizing the central antioxidant glutathione, are altered in patients with schizophrenia spectrum disorders.Objective: determination of activity of platelet glutathione reductase (GR) and glutathione-S-transferase (GST) in patients with late-onset schizophrenic spectrum disorders (LOS - spectrum psychoses) and evaluation of their possible connection to clinical indicators.Patients and methods: 28 female in-patients aged 45–86 years with LOS-spectrum psychoses were examined: schizophrenia (n = 16), schizoaffective disorder (n = 6), chronic delusional disorder (n = 6). A control group of women of the same age range without mental and neurological diseases was recruited. Platelet GR and GST activities in patients were determined before and after the course of pharmacotherapy, and in the control group - only once.Results: assessment of the patients’ symptoms’ severity using PANSS, HAMD, and MMSE was carried out before and after the course of pharmacotherapy (at the 28th day of the therapy course). The efficacy of therapy was determined by the change in the PANSS and HAMD total score. While the GR activity did not differ significantly in patients and in the control group, GST activity was found substantially and significantly reduced in patients (before and after the course of therapy) compared with the control group, although GST activity in patients did not significantly change during their treatment. In both cases (GR and GST), three patients were observed among the patients with enzymatic activity exceeding > 1.5 times the medians in the group. After the course of treatment, the activity of enzymes decreased to a level within the range of control values or values for other patients.Conclusion: the results of a pilot study indicate the promise of determining the activity of GR and GST in a group of patients with LOS-spectrum endogenous psychoses to distinguish among them subgroups with glutathione metabolism abnormalities that correlate with clinical and pathopsychological features.