Abstract
BACKGROUND: Depressive/anxiety disorders are the most common types of mental illnesses in the world. The present study was the first to explore the association between plasma microRNAs (miRNAs) and depression/anxiety in primary care patients. RESULTS: In total, 169 patients (aged 20-64 years) from 16 primary health centers were enrolled in the present study. The healthy controls were consisted of 52 individuals. We first performed miRNA screening of plasma samples from 11 patients using a Serum/Plasma Focus microRNA Panel comprising 179 miRNA primer sets. Six miRNAs were differentially expressed and were then validated by quantitative real-time (qRT)-PCR in the entire study cohort. The mean plasma miR-144-5p level in the depression/anxiety patients increased significantly compared to baseline (p < 0.0001) after the 8-week follow-up. No significant associations were found between the differentially expressed miRNAs and a change in the Montgomery-Åsberg Depression Rating Scale (MADRS-S) score after the follow-up. In linear regression analysis, the plasma miR-144-5p expression level was inversely related to the depression score (MADRS-S) (β = -0.02, p < 0.01), after adjustment for sex and age, at baseline. In addition, plasma miR-144-5p levels at baseline in the depression/anxiety patients were significantly lower compared with the healthy controls (p < 0.001). CONCLUSIONS: Our findings show that plasma miR-144-5p levels are associated with depressive symptoms. Although confirmatory analyses are required, plasma miRNA-144-5p is a potential peripheral biomarker for pathologic processes related to depression.