Comparison of plasma MicroRNA levels in drug naive, first episode depressed patients and healthy controls.

Major depression is the most common psychiatric disorder. The diagnosis of depression depends on a patient's subjective complaints, and the nature of the heterogeneous disorder. Thus, there is no known biomarker for depression to date. Previous research has indicated that microRNAs are dysregulated in bipolar disorder and schizophrenia. We aimed to investigate microRNA dysregulation in plasma samples of patients with major depression. Venous blood samples of 50 depressed patients and 41 healthy controls were collected and the quantification of microRNAs was established using qRT-PCR. We found miR-320a significantly downregulated and miR-451a significantly upregulated in depressed patients. We also found miR-17-5p and miR-223-3p upregulated, but not as significantly as miR-451a. Merging our results with previous published data shows that the blood miR-320 family may be a potential microRNA family dysregulated in major depression. Research should be performed on miR-320-related pathways and their relationship to depression. Additionally, miR-451a could serve as a candidate biomarker for depression based on the acting mechanism of ketamine. Studies targeting miR-451a levels before and after treatment could be helpful.