Current evidence on mesenchymal stem cell therapy for traumatic spinal cord injury: systematic review and meta-analysis

Background aims: The authors aim to analyze the evidence in the literature regarding the efficacy and safety of mesenchymal stem cell (MSC) therapy in human subjects with traumatic spinal cord injury (SCI) and identify its potential role in the management of SCI.

Methods: The authors conducted independent and duplicate searches of electronic databases, including PubMed, Embase and the Cochrane Library, until May 2020 for studies analyzing the efficacy and safety of stem cell therapy for SCI. American Spine Injury Association (ASIA) impairment scale (AIS) grade improvement, ASIA sensorimotor score, activities of daily living score, residual urine volume, bladder function improvement, somatosensory evoked potential (SSEP) improvement and adverse reactions were the outcomes analyzed. Analysis was performed in R platform using OpenMeta[Analyst] software.

Results: Nineteen studies involving 670 patients were included for analysis. On analysis, the intervention group showed statistically significant improvement in AIS grade (P < 0.001), ASIA sensory score (P < 0.017), light touch (P < 0.001), pinprick (P = 0.046), bladder function (P = 0.012), residual urine volume (P = 0.023) and SSEP (P = 0.002). However, no significant difference was noted in motor score (P = 0.193) or activities of daily living score (P = 0.161). Although the intervention group had a significant increase in complications (P < 0.001), no serious or permanent adverse events were reported. On subgroup analysis, low concentration of MSCs (<5 × 10⁷ cells) and initial AIS grade A presentation showed significantly better outcomes than their counterparts.

Conclusions: The authors' analysis establishes the efficacy and safety of MSC transplantation in terms of improvement in AIS grade, ASIA sensory score, bladder function and electrophysiological parameters like SSEP compared with controls, without major adverse events. However, further research is needed to standardize dose, timing, route and source of MSCs used for transplantation.