Optimizing olfactory ensheathing cell transplantation for spinal cord injury repair.

Cell transplantation constitutes an important avenue for development of new treatments for spinal cord injury. These therapies are aimed at supporting neural repair and/or replacing lost cells at the injury site. To date, various cell types have been trialled with most studies focussing on different types of stem cells or glial cells. Here, we review commonly used cell transplantation approaches for SCI repair, with focus on transplantation of olfactory ensheathing cells (OECs), the glial cells of the primary olfactory nervous system. OECs are promising candidates for promotion of neural repair as they support the continuous regeneration of the olfactory nerve that occurs throughout life. Furthermore, OECs can be accessed from the nasal mucosa (olfactory neuroepithelium) at the roof of the nasal cavity and can be autologously transplanted. OEC transplantation has been trialled in many animal models of SCI, as well as in human clinical trials. Whilst several studies have been promising, outcomes are variable and the method needs improvement to enhance aspects such as cell survival, integration and migration. As a case study, we include the approaches used by our team (the Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University) to address the current problems with OEC transplantation and discuss how the therapeutic potential of OEC transplantation can be improved. Our approach includes discovery research to improve our knowledge of OEC biology, identifying natural and synthetic compounds to stimulate the neural repair properties of OECs, and designing three-dimensional cell constructs to create stable and transplantable cell structures.