摘要Olfactory ensheathing cells (OECs) are crucial players in the continuous regeneration of the olfactory nervous system that occurs through out life and are thought to have unique growth-promoting properties. For this reason, OEC transplantation has been thoroughly explored for the poten-tial to promote neural repair after both central and peripheral nervous system injuries. Numerous studies have shown that OEC transplantation is safe and can promote recovery after spinal cord injury (SCI), both in animal models and in human clinical trials. To date, a variety of injury types and time-points after injury, as well as different delivery methods, have been tested. Outcomes have been encouraging (in rodent models including, for example, restoration of locomotion, breathing and climb-ing ability along with induction of axonal sprouting and some axonal regeneration) but highly variable (Barnett and Riddell, 2007; Gomez et al., 2018). In their natural environment of the primary olfactory nervous system (the olfactory nerve and outer layer of the olfactory bulb), OECs provide structural support for olfactory axons and secrete a range of growth and guidance factors as well as basement membrane components. OECs also phagocytose debris arising from degenerating axons (Ekberg and St John, 2014). In the injured spinal cord, OECs (in addition to these functions) also exhibit a unique capacity for migration into scar tissue and for integration with astrocytes (Barnett and Riddell, 2007; Gomez et al., 2018). For these neural repair effects to occur, it is essential that the transplanted cells survive over time. The key factor for success is thus that the OECs must not only arrive at the right place within the injury site, but must also over time integrate and interact with the injured tissue. To date, many studies do not report on OEC survival and it is thus not well known how many of the transplanted cells survive over time. A recent review (Reshamwala et al., 2019) focused specifically on OEC survival after transplantation in rodent models of SCI over the last 10 years, constituting the first published review article that specifically addresses the link between cell survival and SCI repair. The review an-alyzed how different studies have determined cell survival, assessed the methodologies used throughout the studies (injury model, method of cell delivery, identification of OECs after transplantation) as well as the in-terrelationship between cell survival and functional/structural outcomes. The review confirmed that cell survival has not often been discussed or quantified in the published animal trials; the reason being that it is difficult to track the cells after transplantation. OECs do not express any characterized cell-specific markers that definitively identify them from other glial cells. Thus, establishment of a panel of markers labeling OECs is essential.