Local and Remote Growth Factor Effects after Primate Spinal Cord Injury

The Journal of Neuroscience, 2010 · DOI: 10.1523/JNEUROSCI.1924-10.2010 · Published: July 21, 2010

Simple Explanation

This study investigates how growth factors affect nerve cells after spinal cord injury in primates, focusing on both local effects at the injury site and remote effects in the brain. The researchers found that delivering brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) to the injury site promoted axonal growth locally and reduced atrophy of motor neurons in the brain. This suggests that injured nerve systems can respond to growth signals over long distances, potentially paving the way for therapies that enhance axonal plasticity and regeneration.

Study Duration

6 Months

Participants

15 adult rhesus primates

Evidence Level

Not specified

Key Findings

1
Neurotrophic factors (BDNF and NT-3) administered at the site of spinal cord injury in primates promoted regeneration of axons into the local lesion site.
2
The same neurotrophic factors ameliorated distant, corticospinal neuronal atrophy in the motor cortex, suggesting a remote protective effect.
3
Rodent models indicated that BDNF, rather than NT-3, was primarily responsible for the remote protection of corticospinal neurons in the brain.

Research Summary

The study examined the local and remote neuronal responses to neurotrophic factor-secreting cell grafts placed within sites of right C7 hemisection lesions in the rhesus macaque. Six months after gene delivery of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) into C7 lesion sites, local effects on axonal growth, and remote effects reflected in significant reductions in axotomy-induced atrophy of large pyramidal neurons within the primary motor cortex were found. Injured neural systems retain the ability to respond to growth signals over the extended distances of the primate CNS, promoting local axonal growth and preventing lesion-induced neuronal degeneration at a distance.

Practical Implications

Therapeutic Potential

Spinally administered growth factors could “prime” neurons to respond to experimental therapies promoting axonal plasticity or regeneration.

Understanding SCI

The study provides insights into the mechanisms of neuronal responses to spinal cord injury over extended distances in primate systems.

Drug Development

Findings may inform the development of more effective therapies for spinal cord injury by targeting both local and remote effects.

Study Limitations

1
Limited number of experimental subjects and control groups in primate studies.
2
Functional outcomes after growth factor administration are a subject of ongoing experiments and not fully addressed in this report.
3
Study focuses primarily on anatomical outcomes rather than detailed functional analyses.

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