Oxidative metabolism and urotensin-II levels among bipolar disorder patients in manic episode

Objective: According to the previous studies, it has been noted many times that oxidative balance is disrupted in bipolar disorder. However, we did not found any research investigating the Urotensin-II (U-II) levels and relationship between U-II levels and oxidative metabolism among bipolar disorder patients in the literature. In this study, we aimed to investigate the U-II levels, oxidative metabolism and relationship between U-II levels and oxidative metabolism among bipolar disorder patients in manic episode. Method: Fourty two patients diagnosed as bipolar disorder manic episode according to DSM-5 and 55 healthy controls enrolled into the study. Serum total antioxidant status (TAS), total oxidant status (TOS), nitric oxide (NO), U-II and oxidative stress index (OSI) measurements were done in biochemistry laboratory of Gaziantep University. Results: When TAS, TOS, OSI, NO and U-II levels were compared between bipolar disorder manic episode patients and control group; TAS, TOS, OSI, NO and U-II levels were significantly higher in the patient group than the control group (p = 0.003, p = 0.001, p = 0.001, p = 0.001 and p = 0.009 respectively). According to the correlation analysis, U-II levels were found to have a poor linear correlation in the positive direction with TOS and OSI (r = 0.326, p = 0.035 for TOS; and r = 0.369, p = 0.016 for OSI). Conclusion: TAS, TOS, OSI and NO levels were higher in bipolar disorder manic episode patients when compared with controls in concordance with many of the previously conducted studies. Another important finding of our study is the higher U-II levels in bipolar disorder manic episode patients than controls. In the earlier studies, data have been obtained about the effects of U-II on behavior, sleep, inflammatory system and oxidative metabolism and relevant hypotheses have been established. In the light of these studies in the literature, our study proposes that increased U-II levels could be a factor effecting the elevated oxidative stress and inflammation in patients with bipolar disorder manic episode. Keeping this in mind, one can assume that one of the reasons of behavioral and sleep disturbances seen in the clinical features of bipolar disorder manic episode could be the elevated U-II levels. Additionally, findings of increased NO and adrenomedullin levels from the cerebral blood flow studies may be indirectly associated with the effect of U-II. However, effects of U-II on human brain vessels, especially in the prefrontal cortex has not been studied yet. The association between cerebral blood flow and U-II should be the subject of further studies. Our study is the first one to examine U-II levels as well as relationship between U-II levels and oxidative parameters in manic episode of bipolar disorder, therefore it may significantly contribute to the literature.