Production of reactive oxygen species by blood platelets in patients with schizophrenia after stimulation with platelet activating factor

Generation of reactive oxygen species (ROS) and lipid peroxidation in blood platelets were determined in patients with paranoid schizophrenia (acc. to DSM-IV) during exacerbation of psychotic symptoms and in healthy volunteers. Measurements of chemiluminescence emitted by blood platelets (PAF-stimulated and non-stimulated) were performed in an automatic luminescence analyzer (Berthold LB 950) according to the method described by Krol et al. (1990). Measurements of lipid peroxidation in blood platelets was performed by measuring the concentration of thobarbituric acid-reactive substances (TBARS) according to the method described by Rice-Evans. Our results suggest, that persons with schizophrenia exhibit a significantly higher production of reactive oxygen species and a significantly higher level of TBARS than in healthy persons. There was a significant difference between PAF-stimulated platelet chemiluminescence in patients with schizophrenia as compared with healthy persons (p=0.03). The results of this study suggest, that persons with schizophrenia during exacerbation of psychotic symptoms experience an increased production of reactive oxygen species, leading to greater oxidative stress and an altered response to PAF stimulation. In patients with schizophrenia, altered platelet response to PAF stimulation may be due to the changes of the platelet PAF receptor activity (desensitization), to an altered NMDA receptor (stimulation) and to a disturbed platelet activation mediated by secondary events associated with oxidative stress.