Evaluation of Olfactory Ensheathing and Schwann Cells after Implantation into a Dorsal Injury of Adult Rat Spinal Cord

Abstract

Olfactory ensheathing cells (OECs) and Schwann cells (SCs) obtained from adult transgenic rats expressing alkaline phosphatase (AP) were studied following implantation into intact spinal cord and after dorsal column crush (DCC) injury, either within the lesion or near the lesion borders. We observed no evidence of migration of AP OECs or AP SCs after lesion site injections, with most cells remaining in or nearby the injection/lesion site. Acute injection of either cell type outside of the lesion site resulted in the presence of cells in the lesion even two hours after injection. However, after a 2-week delay between DCC injury and cell injection, only OECs injected 2.5-mm outside of a DCC lesion entered the lesion, while SCs did not pass a region of increased astroglial immunoreactivity. GFAP-immunoreactivity also revealed differences in the astroglial scar at the lesion border with openings apparent in this region only in the OEC group. SCs induced greater ingrowth of CGRP-positive axons within the lesion, two weeks post-injury. Equivalent numbers of GAP-43-positive axons grew within the lesion after SC or OEC implantation. These findings show that, although there is no active migration for either cell type, both OECs and SCs are able to support axonal regrowth and/or sprouting into the lesion. The openings in the astroglial boundary at the lesion site may give OECs a potential advantage over SCs in promoting axonal growth through the astroglial scar.

The Migration of Olfactory Ensheathing Cells during Development and Regeneration

“…Schwann cells enwrap and myelinate individual axons after transplantation [69] but do not integrate well within the central nervous system [70,71]. OECs on the other hand wrap up groups of unmyelinated axons and can integrate well in both the peripheral nervous system and central nervous system since they are naturally present in the primary olfactory nervous system at the peripheral-central nervous system interface.…”

Astrocyte-Produced Ephrins Inhibit Schwann Cell Migration via VAV2 Signaling

“…One of the main problems is that the cells show very limited migration from the site of implantation and do not intermingle with host astrocytes (Sims and Gilmore, 1994;Sims et al, 1998;Fraher, 1999;Lakatos et al, 2000;Andrews and Stelzner, 2007). Interfaces between Schwann cell and astrocyte territory are characterized by a sharp boundary of reactive astrocytes expressing, among other molecules, inhibitory chondroitin sulfate proteoglycans (CSPGs) (Geller and Fawcett, 2002;Silver and Miller, 2004).…”

The Immunohistochemical Characterization of Human Fetal Olfactory Bulb and Olfactory Ensheathing Cells in Culture as a Source for Clinical CNS Restoration

“…More and more literature reviews give us more and more hope that OEC transplantation to be one of the most promising therapeutic strategies (Barnett and Riddell, 2007;Sasaki et al, 2007;Bauchet et al, 2008;Bunge, 2008;Radtke et al, 2008;Richter and Roskams, 2008;Kawaja et al, 2009); OECs have been successfully transplanted in acute (Resnick et al, 2003;Polentes et al, 2004;Collazos-Castro et al, 2005;Lopez-Vales et al, 2006;Andrews and Stelzner, 2007;Sasaki et al, 2007) and chronic (Andrews and Stelzner, 2004;Lopez-Vales et al, 2007) models of rodent spinal cord injury. Data obtained using various injury models support the view that OEC transplants can reduce cavitation, increase axonal sprouting and regeneration, and a moderate degree of functional motoric recovery (Li et al, 1997;Ramon-Cueto et al, 2000;Collazos-Castro et al, 2005;Lopez-Vales et al, 2007;Sasaki et al, 2007).…”