Transplantation of human umbilical cord mesenchymal stem cells optimized with IFN-γ is a potential procedure for modification of motor impairment in multiple sclerosis cases: a preclinical systematic review and meta-analysis study.

Stem cells transplantation (SCT) is known as a newfound strategy for multiple sclerosis (MS) treatment. Human umbilical cord mesenchymal stem cells (hUCMSCs) contain various regenerative features. Experimental autoimmune encephalomyelitis (EAE) is a laboratory model of MS. This meta-analysis study was conducted to assess the overall therapeutic effects of hUCMSCs on reduction of clinical score (CS) and restoration of active movement in EAE-induced animals. For comprehensive searching (in various English and Persian databases until May 1, 2024), the main keywords of "Experimental Autoimmune Encephalomyelitis", "Multiple Sclerosis", "Human", "Umbilical Cord", "Mesenchymal", and "Stem Cell" were hired. Collected data were transferred to the citation manager software (EndNote x8) and duplicate papers were merged. Primary and secondary screenings were applied (according to the inclusion and exclusion criteria) and eligible studies were prepared for data collection. CS of two phases of peak and recovery of EAE were extracted as the difference in means and various analyses including heterogeneity, publication bias, funnel plot, and sensitivity index were reported. Meta-analysis was applied by CMA software (v.2), P <0.05 was considered a significant level, and the confidence interval (CI) was determined 95% (95% CI). Six eligible high-quality (approved by ARRIVE checklist) papers were gathered. The difference in means of peak and recovery phases were -0.775 (-1.325 to -0.225; P =0.006; I 2 =90.417%) and -1.230 (-1.759 to -0.700; P <0.001; I 2 =93.402%), respectively. The overall therapeutic effects of SCT of hUCMSCs on the EAE cases was -1.011 (95% CI=-1.392 to -0.629; P =0.001). hUCMSCs transplantation through the intravenous route to the animal MS model (EAE) seems a considerably effective procedure for the alleviation of motor defects in both phases of peak and recovery.