Effect of duloxetine on changes in serum proinflammatory cytokine levels in patients with major depressive disorder.

ABSTRACT

OBJECTIVE: Accumulating evidence supports the idea that inflammation may contribute to the pathophysiology of major depressive disorder (MDD). Duloxetine, a serotonin-norepinephrine reuptake inhibitor, exhibits anti-inflammatory effects both in vitro and in vivo. In this study, we investigated the impact of duloxetine on changes in serum proinflammatory cytokine levels among individuals diagnosed with MDD. METHODS: A cohort of 23 drug-naïve individuals diagnosed with MDD and 23 healthy controls were included in this study. The severity of depressive symptoms was evaluated using the 24-item Hamilton Depression Scale (HAMD-24). A panel of 7 proinflammatory cytokines, including interleukin-1ß (IL-1ß), IL-2, IL-6, IL-8, IL-12, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ), were quantified using multiplex Luminex assays. The levels of serum cytokines in healthy controls and patients with MDD were compared at baseline. All patients received duloxetine at a dosage range of 40-60 mg/day for a duration of 4 weeks. The HAMD-24 scores and serum cytokine levels were compared before and after duloxetine treatment. RESULTS: Compared with healthy controls, patients with MDD had significantly greater levels of IL-2, IL-6, IL-8, IL-12, TNF-α, and IFN-γ (P < 0.05). Moreover, there was a significant decrease in HAMD-24 scores observed pre- and post-treatment (t = 13.161, P < 0.001). Furthermore, after 4 weeks of treatment, the serum levels of IL-8 (t = 3.605, P = 0.002), IL-12 (t = 2.559, P = 0.018), and IFN-γ (t = 3.567, P = 0.002) decreased significantly. However, there were no significant differences in other cytokines, including IL-1ß, IL-2, IL-6, and TNF-α, before and after treatment (P > 0.05). CONCLUSIONS: These findings present compelling evidence, potentially for the first time, indicating that duloxetine treatment may effectively reduce the serum concentrations of IL-8, IL-12, and IFN-γ in individuals diagnosed with MDD. However, the precise mechanisms underlying this effect remain unclear and warrant further investigation.