Effect of stem cell-based therapy for ischemic stroke treatment: A meta-analysis

Stroke is a major cause of death and long-term disability worldwide. Cell-based therapies improve neural functional recovery in pre-clinical studies, but clinical results require evaluation. We aimed to assess the effects of mesenchymal stem cells on ischemic stroke treatment. We searched the PubMed, Embase and Cochrane databases until July 2015 and selected the controlled trials using mesenchymal stem cells for ischemic stroke treatment compared with cell-free treatment. We assessed the results by meta-analysis using the error matrix approach, and we assessed the association of mesenchymal stem cell counts with treatment effect by dose-response meta-analysis. Seven trials were included. Manhattan plots revealed no obvious advantage of the application of stem cells to treat ischemic stroke. For the comprehensive evaluation index, stem cell treatment did not significantly reduce the mortality of ischemic stroke patients (relative risk (RR) 0.59, 95% confidence interval (CI) 0.29-1.19; ln(RR) 0.54, 95% CI -0.18 to 1.25, p=0.141). The National Institutes of Health Stroke Scale was also not significantly improved by stem cell treatment (standardized mean difference (SMD) 0.94, 95% CI -0.13 to 2.01, p=0.072). The European Stroke Scale was significantly improved using the stem cell treatment (SMD 1.15, 95% CI 0.37-1.92). The dose-response meta-analysis did not reveal a significant linear regression relationship between the number of stem cells and therapeutic effect, except regarding the National Institutes of Health Stroke Scale index. In conclusion, our assessments indicated no significant difference between stem cell and cell-free treatments. Further research is needed to discover more effective stem cell-based therapies for ischemic stroke treatment.