Olfactory Ensheathing Cells Do Not Exhibit Unique Migratory or Axonal Growth-Promoting Properties after Spinal Cord Injury

The Journal of Neuroscience, 2006 · DOI: 10.1523/JNEUROSCI.3264-06.2006 · Published: October 25, 2006

Spinal Cord Injury Regenerative Medicine Neurology

Simple Explanation

This study investigates whether olfactory ensheathing cells (OECs) have unique properties that promote migration and axonal growth after spinal cord injury (SCI). The study found that OECs do not exhibit unique migratory properties when grafted to the spinal cord. The research indicates that OECs do not show a detectable difference in promoting axon growth into a SCI site compared with bone marrow stromal cells (MSCs) or fibroblasts. Control injections of MSCs or fibroblasts also dispersed into the lesion cavity. Furthermore, OECs do not support the bridging of corticospinal axons beyond a dorsal column lesion. The study suggests that the observed cell tracts may be due to passive spreading from pressure injections rather than active migration.

Study Duration

1 month

Participants

66 adult female Fischer 344 rats

Evidence Level

Not specified

Key Findings

1
OECs do not exhibit significant migratory properties when grafted to the spinal cord after SCI.
2
OECs do not show a detectable difference in promoting axon growth into a SCI site compared with MSCs or fibroblasts.
3
OECs do not support the bridging of corticospinal axons beyond a dorsal column lesion.

Research Summary

The study aimed to understand the mechanisms of OEC migration and axonal guidance after SCI by injecting lamina propria OECs near SCI sites. The findings indicate that OECs form cell tracts that displace host astrocytes but do not preferentially support the extension of long tract axons, including corticospinal axons. The research suggests that OECs do not have unique migratory properties or enhanced axonal growth-promoting capabilities compared to MSCs or fibroblasts in the context of spinal cord injury.

Practical Implications

Re-evaluation of OEC Therapy

The study challenges the assumption that OECs have unique regenerative properties for spinal cord injury, suggesting a need to re-evaluate their therapeutic potential.

Alternative Cell Therapies

The findings suggest that other cell types, such as MSCs or fibroblasts, may be equally effective as OECs in promoting axonal growth into a lesion site.

Understanding Cell Tract Formation

The research highlights the importance of considering the pressure injection phenomenon and the longitudinal orientation of white matter tracts when studying cell migration in the spinal cord.

Study Limitations

1
The study focused on a specific cervical spinal cord dorsal column wire-knife lesion model, which may not be representative of all SCI types.
2
The study used a rat model, and the results may not be directly applicable to human SCI.
3
The study assessed axon growth based on the density of neurofilament-labeled axons and anterograde tracing with BDA and CTB, which may not fully capture the functional aspects of axonal regeneration.

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