Efficacy and Safety of Bone Marrow Stem Cell Therapy versus Umbilical Cord Blood Infusions in Patients With Ischemic Stroke: A Systematic Review and Frequentist Network Meta-Analysis

Introduction: Stem cell therapy, including bone marrow stem cell (BMSC) therapy and umbilical cord blood (UCB) infusions, shows promise for treating acute and subacute ischemic strokes. This systematic review and network meta-analysis (NMA) compares the efficacy and safety of BMSC therapy, UCB infusions, and control interventions (sham, placebo, or no treatment) in randomized controlled trials (RCTs), evaluating functional recovery, stroke-related disability, and overall clinical outcome to determine optimal therapeutic approaches.

Methods: We conducted a comprehensive search in MEDLINE, Embase, Scopus and Web of Science to identify RCTs of BMSC therapy and UCB infusions in acute and subacute ischemic stroke patients. Extracted outcomes included the National Institutes of Health Stroke Scale (NIHSS), Modified Rankin Score (mRS), and Barthel Index for Activities of Daily Living (BI). A frequentist network meta-analysis (NMA) was performed using R studio’s meta package with the random-effects model to assess the relative efficacy and safety across interventions. Results were synthesized as mean differences (MD ± SD) with 95% confidence intervals (CI).

Results: 7 RCTs with a total of 496 patients were included. 66.7% had an acute ischemic stroke while 33.3% had a subacute ischemic stroke. 17.2% were assigned to UCB infusions, while 82.8% underwent BMSC therapy. Analysis showed no statistically significant differences in mRS (MD= -0.20, 95% CI: -0.74 to 0.35, p= 0.47 in BMSC and MD= 0.00, 95% CI: -1.91 to 1.91, p= 1.00 for UCB) nor NIHSS (MD= -0.68, 95% CI: -2.05 to 0.69, p= 0.3327 in BMSC and MD= -0.10, 95% CI: -3.12 to 2.92, p= 0.95 for UCB) between the three arms​​. These findings, confirmed through pairwise meta-analysis, suggest no substantial superiority of either intervention over controls.

Conclusion : Neither BMSC nor UCBI significantly improved functional neurological outcomes, such as NIHSS. However, further in-depth RCTs are needed to explore why these promising therapies failed to show positive results.