Chapter 22: Transplantation of olfactory ensheathing cells for peripheral nerve regeneration

Peripheral nerve injury is a common clinical problem, and the development of novel strategies to enhance peripheral nerve regeneration is important. Traumatic events, including motor vehicle accidents, sports-related injuries, violence, and falls, lead to significant numbers of peripheral nerve lesions. Traumatic nerve injuries are often associated with life-threatening injuries, which must be treated first. During the delay in nerve repair, the transected nerves undergo Wallerian degeneration. Therefore, delay before surgical treatment is critical, but care must also be taken to ensure that nerve reapposition is performed in a manner that will result in a therapeutic benefit. Peripheral nerve repair after transection injury combined with transplantation of myelin-forming glia cells, for example, Schwann cells (SCs) or olfactory ensheathing cells (OECs), may facilitate the regenerative process. Cell-based therapies are being considered in clinical trials for a number of neurological diseases, including multiple sclerosis, spinal cord injury, Parkinson's disease, and stroke. The rationale is that transplanted cells may provide neuroprotection by production of chemokines and neurotrophins or could serve as a replacement therapy. A number of cells derived from adult peripheral tissues for cell therapies are also being actively investigated. These cells include SCs from peripheral nerve, olfactory OECs from the olfactory system, and stromal cells from bone marrow (mesenchymal stem cells, MSCs). In principle, these cells could be derived autologously, and used acutely or expanded in culture and used for cell-based therapies. Here, we review experimental work demonstrating the potential of one of these cells, the OEC, as an experimental tool for promoting recovery in peripheral nerve injury.