ROS-Induced DNA Damage Associates with Abundance of Mitochondrial DNA in White Blood Cells of the Untreated Schizophrenic Patients

OBJECTIVE: The aim of this study was (1) to examine the leukocyte mtDNA copy number (CN) in unmedicated (SZ (m−)) and medicated (SZ (m+)) male patients with paranoid schizophrenia (SZ) in comparison with the healthy male controls (HC) and (2) to compare the leukocyte mtDNA CN with the content of an oxidation marker 8-oxodG in lymphocytes of the SZ (m−) patients. METHODS: We evaluated leukocyte mtDNA CN of 110 subjects with SZ in comparison with 60 male HC by the method qPCR (ratio mtDNA/nDNA (gene B2M) was detected). SZ patients were divided into two subgroups. The patients of the subgroups SZ (m+) (N = 55) were treated with standard antipsychotic medications in the hospital. The patients of the subgroup SZ (m−) (N = 55) were not treated before venous blood was sampled. To evaluate oxidative DNA damage, we quantified the levels of 8-oxodG in lymphocytes (flow cytometry) of SZ (m−) patients (N = 55) and HC (N = 30). RESULTS: The leukocyte mtDNA CN showed no significant difference in SZ (m+) patients and HC. The mtDNA CN in the unmedicated subgroup SZ (m−) was significantly higher than that in the SZ (m+) subgroup or in HC group. The level of 8-oxodG in the subgroup SZ (m−) was significantly higher than that in HC group. CONCLUSION: The leukocytes of the unmedicated SZ male patients with acute psychosis contain more mtDNA than the leukocytes of the male SZ patients treated with antipsychotic medications or the healthy controls. MtDNA content positively correlates with the level of 8-oxodG in the unmedicated SZ patients.