Investigation of serum USP9X and HMGB1 levels in schizophrenia patients during remission and psychotic flare-up periods compared to healthy controls

In our study, the relationship between HMGB1 levels, which is one of the late mediators of inflammation, and USP9X levels implicated in the etiopathogenesis of neurodevelopmental disorders, in schizophrenia patients during two different periods of the disease, namely acute psychotic flare-up and remission periods, was investigated and compared with healthy controls. Written informed consents were obtained from the patients and healthy controls with the approval of our hospital's ethics committee. A total of 53 patients in remission phase, 53 patients undergoing treatment for acute psychotic flare-up, and 53 healthy controls, diagnosed with schizophrenia according to DSM-5 diagnostic criteria and voluntarily agreeing to participate, were included in our study. Venous blood samples were collected from all participants after a 12-hour fasting period, between 08:00-10:00 in the morning, to measure serum HMGB1 and USP9X levels. The values of the participants were measured using the ELISA method at the Gaziantep University Biochemistry Laboratory. SPSS version 22.0 for Windows and MedCalc version 19.8 software packages were used for the analyses. P<0.05 was considered statistically significant. When the patient and control groups were compared in terms of HMGB1 and USP9X values, a statistically significant difference was found (p<0.05 for both). There was a weak positive correlation between HMGB1 levels and the PANSS Negative subscale, and a weak negative correlation between USP9X levels and the Trail Making Test Part A scores (p=0.032, r=0.75; p=0.029, r=0.309, respectively). As far as we know, there is no study in the literature that combines the inflammatory and neurodevelopmental theories of schizophrenia. Our study is important in terms of contributing to the literature as it is the first study to evaluate both the inflammatory and neurodevelopmental theories together. This is also the first study to clinically measure USP9X in schizophrenia. We believe that understanding the etiology and pathophysiology of schizophrenia, objectively assessing the severity of the disease, and developing new treatment methods will be important in the context of HMGB1 and USP9X.