Effects of intravenous pulse methylprednisolone in neuromyelitis optica during the acute phase.

BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) is an anti-aquaporin 4 (anti-AQP4) autoantibodies-mediated idiopathic inflammatory demyelinating disease of the central nervous system. While intravenous pulse methylprednisolone (IVMP) is the recommended initial treatment option for acute onset NMOSD, its therapeutic mechanism remains unclear. We hypothesized that IVMP would reduce the expression of pro-inflammatory factors and increase the resolution of inflammation in patients with NMOSD. METHODS: Mendelian randomization (MR) analysis was used to screen meaningful inflammatory and resolution factors for inclusion. Three MR methods with inverse variance weighting (IVW) were primarily used to identify positive results. Interleukin (IL)-10, IL-1β, IL-6, C-X-C motif chemokine ligand 12 (CXCL12), and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) were screened from 41 inflammatory factors, and resolvin D1 (RvD1), maresin 1 (MaR1), and lipoxin A4 (LXA4) were screened from 6 resolution markers for inclusion. Subsequently, 12 patients with NMOSD were enrolled and treated with IVMP. Serum levels of the aforementioned inflammatory and resolution markers were measured by enzyme-linked immunosorbent assay before and after IVMP treatment. RESULTS: High levels of TRAIL, CXCL12, and IL-1β were associated with an increased risk of NMOSD (TRAIL: odds ratio [OR], 1.582; 95% confidence interval [CI], 1.003-2.495; CXCL12: OR, 3.610; 95% CI, 1.011-12.889; IL-1β: OR, 4.500; 95% CI, 1.129-17.927). High levels of RvD1, MaR1, and LXA4 were associated with a reduced risk of NMOSD (RvD1: OR, 0.725; 95% CI, 0.538-0.976; MaR1: OR, 0.985; 95% CI, 0.970-0.999; LXA4: OR, 0.849; 95% CI, 0.727-0.993). Among patients with NMOSD, serum levels of IL-6, CXCL12, and TRAIL significantly decreased following IVMP treatment, compared with pretreatment levels, while levels of IL-1β, LXA4, and MaR1 significantly increased after IVMP treatment (p < 0.05). A significant positive correlation was observed between CXCL12 levels and Expanded Disability Status Scale (EDSS) scores (r = 0.451, p < 0.05). CONCLUSION: Several systemic inflammatory regulators associated with the pathogenesis of NMOSD were identified. The protective roles of LXA4 and MaR1 may be indispensable components of glucocorticoid treatment. Therefore, the use of resolution markers may be a potential strategy for improving central nervous system injury in individuals with NMOSD.