Investigation of proline and prolidase and hipoxia i̇nducible factor 1ALPHA, vascular endothelial growth factor, tumor necrosis factor-alpha, interleukin-1, transforming growth factor-beta, nuclear factor kappabeta levels in schizophrenia

Aim: The aim of this study was to investigate the levels of proline, prolidase, HIF-1α, VEGF, TGF-Β, NF-kB, IL-1 and TNF-α in schizophrenia patients who were hospitalized or admitted to the outpatient clinic and to compare with healthy controls. Materials and Methods: Study group was consisted of 48 patients aged between 18-65, diagnosed with schizophrenia according to DSM-5 criteria and treated in Dicle University Hospital Psychiatry clinic between October 2018 and July 2019. 41 healthy subjects who were matched in terms of age, gender, education level and smoking status were included in the study. Study population were divided into 2 groups. Group-1: 48 subjects with schizophrenia Group-2: 41 healthy subjects. Venous blood samples were collected from the participants after at least 8 hours of fasting. Proline, prolidase, HIF-1α, VEGF, TGF-Β, NF-kB, IL-1 and TNF-α levels were studied by ELISA method in the laboratory. Statistical Package for Social Sciences for Windows" (SPSS Inc; Chicago, IL, USA) version 24.0 software were used to analyse the findings. Results: In our study, we found that proline, prolidase, HIF-1α, VEGF, TGF-Β, NF-kB, IL-1 and TNF-α levels were lower in schizophrenia patients compared to control group. The difference VEGF and TNF-α values between the two groups was statistically significant (p=0,048; p=0,045), but there was no significant difference in terms of other biochemical parameters. There was a high positive correlation between all biochemical parameters (p<0,001). In addition, we found that prolidase and proline levels were negatively correlated with the number of hospitalizations and total length of hospitalization. Conclusion: Prolidase enzyme and proline play an important role in the pathogenesis of schizophrenia by affecting inflammatory fates and growth factors through NF-kB and HIF-1α. In order to fully elucidate the role of prolidase in the pathogenesis of schizophrenia, large scale studies are needed to evaluate its effects on the brain pathways. Key words: schizophrenia, proline, prolidase, inflammation, growth factors