Affiliations: Experimental and Regenerative Neuroscience (EaRN),
School of Anatomy and Human Biology (M309), The University of Western
Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
Abstract: The olfactory nerve differs from cranial nerves III-XII in that it
contains a specialised type of glial cell, called 'olfactory ensheathing cell'
(OEC), rather than Schwann cells. In addition, functional neurogenesis persists
postnatally in the olfactory system, i.e. the primary olfactory pathway
continuously rebuilds itself throughout adult life. The presence of OECs in the
olfactory nerve is thought to be critical to this continuous growth process.
Because of this intrinsic capacity for self-repair, the mammalian olfactory
system has proved as a useful model in neuroregeneration studies. In addition,
OECs have been used in transplantation studies to promote pathway regeneration
elsewhere in the nervous system. Here, we have reviewed the parameters that
allow for repair within the primary olfactory pathway and the role that OECs
are thought to play in this process. We conclude that, in addition to intrinsic
growth potential, the presence of an aligned substrate to the target structure
is a fundamental prerequisite for appropriate restoration of connectivity with
the olfactory bulb. Hence, strategies to promote regrowth of injured nerve
pathways should incorporate usage of aligned, oriented substrates of OECs or
other cellular conduits with additional intervention to boost neuronal cell
body responses to injury and/or neutralisation of putative inhibitors.
