Mitochondrial complex I and III mRNA levels in bipolar disorder

Studies that have focused on the mitochondrial electron transport chain indicate that bipolar disorder (BD) is associated with pathology in mitochondrial function. These pathological processes occur in the brain circuits that regulate affective functions, emotions, and motor behaviors. The present study aimed to determine the relationship between mitochondrial complex dysfunction and BD.

The BD group included 32 male patients diagnosed with first-episode manic BD. The control group included 35 sociodemographically matched healthy males. Messenger ribonucleic acid (mRNA) was isolated from peripheral blood samples obtained from the patients and control group, and the mRNA levels of the NDUFV1, NDUFV2, and NDUFS1 genes of mitochondrial complex I and the UQCR10 gene of mitochondrial complex III were investigated.

Significant differences were identified in complex I gene mRNA levels between the BD group (n = 32) and the control group (n = 35) for the following genes: NDUFV1 (P = 0.01), NDUFV2 (P < 0.01), and NDUFS1 (P = 0.02). The UQCR10 gene (complex III) mRNA level did not differ between the groups (P = 0.1). The mRNA levels of the four genes studied were lower at the 3-month follow-up; however, these differences were not significant (P > 0.05).

All of the BD patients were in manic episodes; thus, we were unable to separately compare these levels with those during depressive and euthymic episodes.

The mRNA levels of all of the genes representing the subunits of mitochondrial complex I (NDUFV1, NDUFV2, and NDUFS1) were significantly higher in the present study's BD patients during manic episodes than in the controls. With the data obtained from further research, biomarkers that could be used for the diagnosis and follow-up of neuropsychiatric disorders may be discovered.