Dental Pulp Progenitor Cells: Potential for Spinal Cord Injury Repair?

Clinical trials have recently commenced using embryonic stem cells as a replacement therapy for spinal cord injury. Due to ethical issues, however, alternative stem cell sources are sought-for. Multipotent progenitor cells can be isolated from various dental tissues, including the pulp. Their relative ease of access and high proliferative rates make dental progenitor cells an area of research interest as an alternative to embryonic stem cells for tissue engineering purposes. Electric fields influence the migration of many cell types, including endogenous neuronal progenitors (Meng, X. et al., 2011, Experimental Neurology, 227(1)) and can promote spinal cord regeneration. Objectives: This study aims to investigate the potential of dental pulp progenitor cells as a cell replacement therapy for spinal cord injury in combination with electrostimulation. Methods: Dental pulp was removed from murine incisors and enzymatically digested to a cellular suspension. Following selection by preferential adherence to fibronectin, heterogenous and clonal populations were expanded in vitro and characterised for multipotency markers using RT-PCR and immunocytochemistry techniques. The migratory response of these cells to an applied electric field was analysed by time-lapse recording. Results: Isolated pulp cells express various stem cell markers including the mesenchymal markers CD90 & SCA1, the neuronal precursor markers nestin & musashi and the neural crest marker SOX10. Pulp cells demonstrate a directed migratory response towards the cathode under the influence of an electric field. Conclusion: Cells expressing markers associated with endogenous central nervous system precursors can be isolated from the dental pulp. Furthermore, a directed migratory reponse to an electric field, which is known to influence spinal cord regeneration, is demonstrated. The dental pulp may, therefore, provide a suitable alternative source of progenitor cells for repair and regeneration following spinal cord injury. This study is funded by a Royal Society URF award and ERC starting grant to BS (no:243261)