Background and purpose: Erythropoietin (EPO) was explored regarding its suitability as a candidate stroke drug in animal experimental studies. We performed a meta-analysis to obtain an overall impression of the efficacy of EPO in published animal experimental stroke studies and for potential guidance of future clinical studies.
Methods: By electronic and manual searches of the literature, we identified studies describing the efficacy of EPO in experimental focal cerebral ischemia. Data on study quality, EPO dose, time of administration, and outcome measured as infarct volume or functional deficit were extracted. Data from all studies were pooled by means of a meta-analysis.
Results: Sixteen studies were included in the meta-analysis. When administered after the onset of ischemia, EPO and its analogues reduced infarct size by 32% and improved neurobehavioral deficits significantly. A meta-regression suggests higher doses of EPO to be associated with smaller infarct volumes. When administered earlier than 6 hours EPO was more effective compared to a later treatment initiation. Both hematopoietic and nonhematopoietic EPO analogues showed efficacy in experimental stroke.
Conclusions: In conclusion, this analysis further strengthens confidence in the efficacy of EPO and its analogues in stroke therapy. Nonhematopoietic EPO analogues which are known to have less systemic adverse effects compared to EPO are also promising candidate stroke drugs. Further experimental studies are required that evaluate the safety of a combination of EPO with thrombolysis and whether EPO is also effective in animals with comorbidity.