Spontaneous regeneration of cholecystokinergic reticulospinal axons after a complete spinal cord injury in sea lampreys

Computational and Structural Biotechnology Journal, 2024 · DOI: https://doi.org/10.1016/j.csbj.2023.12.014 · Published: December 19, 2023

Spinal Cord Injury Regenerative Medicine Neurology

Simple Explanation

Lampreys can recover swimming ability after spinal cord injury due to the regeneration of nerve fibers. This study focuses on a specific type of nerve fiber, those that use cholecystokinin (CCK), a signaling molecule. The researchers found that these CCK-using nerve fibers do regenerate after spinal cord injury in lampreys. These fibers also form connections that appear functional, indicated by the presence of synaptic vesicle markers. Furthermore, the extent of regeneration of CCK fibers correlated with improved swimming performance, suggesting that these fibers play a role in the recovery of movement.

Study Duration

10 Weeks

Participants

29 Mature larval sea lampreys

Evidence Level

Not specified

Key Findings

1
CCKergic axons partially regenerate after complete SCI in lampreys, reaching approximately 81% of the axonal profiles seen in uninjured controls by 10 weeks post-injury.
2
Regenerated CCKergic axons show a preference for reinnervation in the lateral regions of the spinal cord, indicating plasticity in the regeneration process.
3
Regenerated CCKergic axons exhibit colocalization with synaptic vesicle marker SV2, suggesting the formation of functional synaptic connections.

Research Summary

This study investigates the spontaneous regeneration of CCKergic descending axons in larval lampreys following a complete SCI. The research demonstrates the partial regeneration of CCKergic axons, with a preference for regeneration in lateral spinal cord regions. The degree of CCKergic reinnervation correlated with improved swimming performance, suggesting a potential role in locomotor recovery.

Practical Implications

Understanding Axon Regeneration

Provides insights into the mechanisms of spontaneous axon regeneration in lampreys, which could inform strategies for promoting regeneration in mammals.

Targeted Therapies

Highlights the potential for targeting specific neuropeptidergic systems, like the CCKergic system, to enhance locomotor recovery after SCI.

Spinal Cord Plasticity

Demonstrates the plasticity of the spinal cord in directing axon regeneration to specific regions, which could be exploited for more effective recovery strategies.

Study Limitations

1
The study is conducted in lampreys, which have a remarkable capacity for spontaneous regeneration that is not observed in mammals, limiting direct translation.
2
The regeneration of CCKergic axons is only partial, and the factors limiting complete regeneration are not fully elucidated.
3
The study establishes a correlation between CCKergic reinnervation and improved swimming performance, but does not demonstrate a direct causal relationship.

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