Clinical application of adult olfactory bulb ensheathing glia for nervous system repair.

The ability of adult olfactory bulb ensheathing glia (OB-OEG) to promote histological and functional neural repair has been broadly documented. Pre-clinical studies show that beneficial effects of adult OB-OEG are repeatable in the same type of spinal cord injury initially tested, in other spinal cord and CNS injury models, in different species and after the administration of these cells in different forms (either alone or in combination with other cells, drugs, products or devices). These studies demonstrate the reproducibility, robustness, fundamental nature and relevance of the findings. Therefore, the use of adult OB-OEG for spinal cord injury repair meets the scientific criteria established by the International Campaign for Cures of Spinal Cord Injury Paralysis (ICCP) for the translation to human application. Because there is so much heterogeneity in the way adult OEG is administered, each of these different OEG-based therapies must be individually categorized to determine whether they fulfill the requisites dictated by the consolidated regulatory body to be considered or not as a medicine. In the case they do, in Europe, they shall be subjected to the Regulatory European Framework for Advanced Therapy Medicinal Products and the European Clinical Trials Directive (Directives 2001/20/EC and 2009/120/EC). After a deep analysis of the European Regulation we have concluded that grafts consisting of suspensions of purified adult OEG, to be used for the promotion of axonal regeneration in the CNS, do not comply with the definition of Medicinal Product provided by the European Medicines Agency. In contrast, experimental therapies using OEG in combination with other cell types, drugs, products or devices, or genetically-modified OEG fall under the definitions of Medicinal Product. This article is part of a Special Issue entitled: Understanding olfactory ensheathing glia and their prospect for nervous system repair.