Neural Stem Cells May Rewire the Immune Response After Spinal Cord Injury

Spinal cord injury sets off a chronic neuroinflammatory cascade in which persistently activated M1 macrophages create a hostile microenvironment that inhibits axonal regeneration and drives secondary tissue damage. A review published in Molecular Biology Reports argues that neural stem cells (NSCs) offer a promising therapeutic strategy not primarily by replacing lost neurons, but by reshaping the inflammatory landscape through immunomodulation.

The review synthesizes evidence on the molecular mechanisms by which NSCs reprogram the immune response after injury. According to the authors, NSCs suppress TLR4/NF-κB signaling, shifting macrophages from a neurotoxic M1 phenotype toward a pro-regenerative M2 phenotype. The cells also engage in reciprocal dialogue with T cells and microglia, creating a neurogenic niche, and they secrete neurotrophic factors that upregulate KCC2 and restore GABAergic inhibition. In addition, NSCs modulate purinergic signaling, a mechanism the authors link to attenuation of neuropathic pain.

However, the review is candid about the limits of the evidence base. Most studies provide correlative rather than causal evidence, and the widely used M1/M2 framework does not fully capture macrophage heterogeneity after spinal cord injury. In the chronic phase in particular, foam cells, pro-fibrotic phenotypes, and disease-associated subpopulations emerge that the simple binary classification fails to describe.

On the question of when to transplant, the review notes that the subacute window is generally associated with superior outcomes, but that optimal timing varies with injury severity, the animal model used, cell source, transplantation route, and cell dose. This variability complicates efforts to draw uniform clinical guidelines from the existing literature.

Clinical translation remains at an early stage. Phase I trials have established feasibility and short-term safety, but the review emphasizes that most of these trials lacked control groups and adequate sample sizes, leaving key questions about efficacy unanswered.

The authors also caution against assuming that neural cell transplantation is inherently safe. Reported adverse effects include allodynia, tumorigenicity, and immune-related complications, underscoring the need for careful monitoring as the field moves forward.

Looking ahead, the review identifies several priorities for future progress: adequately powered clinical trials with objective endpoints, biomarker development, refined immunomodulation strategies, and systematic monitoring for adverse effects. Until such studies are completed, the therapeutic promise of NSC immunomodulation in spinal cord injury remains a hypothesis supported by early-stage and largely preclinical evidence.

Subject of Research: Immunomodulatory mechanisms of neural stem cell therapy in spinal cord injury

Article Title: Molecular Mechanisms of Immunomodulation by Neural Stem Cells in Spinal Cord Injury: From Macrophage Polarization to Therapeutic Plasticity

Article References: Gholami, A. A., babaloo, H., Rahmatov, K., Ward, A., Kubaev, A., Otajonov, I., Xaitov, A., & Moghadam, F. M. (2026). Molecular Mechanisms of Immunomodulation by Neural Stem Cells in Spinal Cord Injury: From Macrophage Polarization to Therapeutic Plasticity. Molecular Biology Reports, 53(1), Article 1827. https://doi.org/10.1007/s11033-026-13070-5

Image Credits: AI Generated

DOI: 10.1007/s11033-026-13070-5

Keywords: spinal cord injury, neural stem cells, macrophage polarization, neuroinflammation, M1/M2 macrophages, TLR4/NF-kB signaling, neurotrophic factors, neuropathic pain, clinical translation, phase I trials, Molecular, Mechanisms