Stem Cell Therapies as an Emerging Paradigm in Stroke (STEPS): bridging basic and clinical science for cellular and neurogenic factor therapy in treating stroke.

Investigators developing cellular therapy for stroke face many challenges. Preclinical models used for cellular therapy studies should be relevant to human stroke and predictive of benefit despite differences in stroke size, cerebrovascular anatomy, immune status, and neurological responses. Translating preclinical testing to human trials is compounded by consideration of delivery method and translation of dosing with cell survival. Many issues must be approached in designing clinical trials of cellular therapy for stroke, including appropriate outcome measures, controlling for confounding factors such as rehabilitation therapy, and possible surrogate outcomes using imaging such as MRI and newer imaging techniques. It is also important to establish standardized clinical protocols and clinical database registries in advance of early proof-of-concept studies. Investigators must adopt a standardized nomenclature and characterization schema for cell products to accurately define potency and determine clinical outcome from early proof-of-concept studies. The Stem Cell Therapies as an Emerging Paradigm in Stroke (STEPS) meeting was organized to bring together clinical and basic researchers with industry and regulatory representatives to assess the critical issues in the field and to create a framework to guide future investigations.