Every year ischemic stroke takes many lives and leaves millions of people with neurological deficits. Currently the only approved therapy is recombinant tissue plasminogen activator, which should be administered within a narrow time window of 4.5 hours. Stem cell therapy was first initiated in several preclinical studies with promising results and lately in some clinical trials. Our research consists of 2 systematic reviews where preclinical and clinical studies were pooled. We provide a systemic review of the evidence of efficacy of cell-based therapy in both preclinical and clinical setting.
After screening of databases, 76 studies were included in our systematic review of studies in rodent stroke models and 4 randomized clinical trials were used for the systematic review of studies in humans. After data extraction and assessment of study quality, the pooled effects were calculated using Revman5.
Stem cell therapy has a positive effect on behavior and histological outcome in rodent stroke models. These results are in line with previously conducted meta-analyses. This improvement in rodents is not translated into clinical trials in humans. Pooled study data of the randomized controlled clinical trials did show a significant improvement in neurologic outcome, but not in functional recovery.
Study quality is pointed out as one of the major reasons for failed translation of preclinical evidence to clinic. Large, well-designed preclinical trials are urgently needed. Good preclinical research is necessary to determine the optimal route of administration, the optimal cell dose and type and the most accurate administration time of the stem cells.