Opioid Signaling in Multiple Sclerosis: Emerging Targets for Repair.

Multiple sclerosis (MS) is a chronic immune-mediated disorder of the central nervous system (CNS) characterized by persistent inflammation, demyelination, and progressive neurodegeneration, driven largely by aberrant activation of T and B lymphocytes that infiltrate the CNS and cause myelin and axonal damage, leading to neurological impairment. Although current therapies broadly suppress immune activity and reduce relapse rates, their effects on neurodegenerative processes remain limited. Also, the safety profile of disease-modifying therapies (DMTs) may become problematic, especially in older patients with comorbidities and/or advanced disability. Emerging data suggest that opioid signaling may exert immunomodulatory, remyelinating, and neuroprotective effects, representing a novel and underexplored therapeutic avenue. Given that current MS therapies primarily target inflammation but fail to promote myelin repair or prevent neurodegeneration, opioid signaling emerges as a novel and underexplored pathway with potential benefits for immunomodulation and remyelination, as well as possible neuroprotective effects. Despite concerns about classical opioid-related adverse effects, accumulating evidence shows that opioid-mediated interventions have been associated with reduced inflammatory activity, attenuation of demyelination, and enhanced neuronal survival and have shown therapeutic benefit in MS. Although current findings are largely preclinical, they provide a compelling rationale for further investigation of the opioid system as a potential adjunctive or novel therapeutic strategy.