Olfactory-ensheathing cell transplantation for peripheral nerve repair: update on recent developments

A number of important advances have been made using transplantation of olfactory-ensheathing cells (OECs) to provide therapeutic effects with regard to peripheral nerve repair. In vivo studies have focused on transplanting OECs to stimulate axonal regeneration and sprouting, increase remyelination, confer neuroprotection, enhance neovascularization and replace lost cells. OECs support axonal regeneration and remyelination with appropriate formation of axonal nodes of Ranvier with improvement of nerve conduction velocity. Current work using gene profiling and proteomics is identifying potential therapeutic differences between OECs harvested from nasal mucosa and the olfactory bulb and genes that OECs express that may be conducive to neural repair. OECs derived from nasal mucosa are of clinical interest since the cells could potentially be harvested from a patient and used for autotransplantation. Various nerve scaffolds and materials have been used for nerve repair and recent studies have examined OECs in combination with various supportive materials, including nanoparticles and scaffolds for peripheral nerve substance defects. This review will discuss the use of OECs in nerve repair and nerve defect injuries with specific emphasis on differences between OECs derived from the olfactory bulb and the olfactory mucosa.