Brexanolone infusion produces sustained anti-inflammatory and neurotrophic effects in patients with postpartum depression that predict symptom improvement.
📄 Abstract
Postpartum depression (PPD) is linked to neuroimmune dysregulation. Brexanolone, an intravenous formulation of the neurosteroid allopregnanolone and the first FDA-approved treatment for PPD, produces rapid and sustained antidepressant effects. However, its long-term mechanisms of action remain unclear. This study evaluated brexanolone's prolonged impact on two groups of biomarkers in whole blood: inflammatory mediators and growth/differentiation/neurotrophic factors. Whole blood was also maintained in culture (4 h) and subjected to lipopolysaccharide (LPS) stimulation of the TLR4 inflammatory pathway. Ten individuals with moderate-to-severe PPD received brexanolone and were assessed before, and at 6 h, ~7, and ~30 days post-infusion. BDNF significantly increased and remained elevated through 30 days, representing a sustained neurotrophic response. In contrast, inflammatory mediators CCL11, IL-6, TNF-α, and IL-18 showed rapid reductions by 6 h. TNF-α suppression lasted up to 7 days, while CCL11 and IL-6 remained suppressed through 30 days. These changes were associated with reductions in Hamilton Depression Rating Scale (HAM-D) scores over time. LPS-stimulated whole blood cultures revealed suppression of TLR4-induced CCL11, IL-1β, IL-6, IL-8, IL-18, TNF-α, HMGB1, and MIP-1β at 6 h. IL-8, IL-18, and TNF-α remained suppressed through 7 days, while IL-1β and CCL11 remained suppressed through 30 days, aligning with sustained HAM-D score improvements. Biomarker × time interactions suggested dynamic regulation of inflammatory and neurotrophic pathways. Given the small sample size, these findings should be interpreted as a pilot study, but they indicate that brexanolone promotes both rapid and sustained anti-inflammatory and neurotrophic effects supporting lasting symptom remission in PPD.