Nogo receptor decoy promotes recovery and corticospinal growth in non-human primate spinal cord injury

Brain, 2020 · DOI: 10.1093/brain/awaa116 · Published: May 6, 2020

Spinal Cord Injury Research Methodology & Design Regenerative Medicine & Stem Cells

Simple Explanation

After a spinal cord injury, the ability of nerve cells to regrow and reconnect is limited by certain inhibitory molecules. This study tested a 'decoy' molecule that blocks these inhibitors. The decoy molecule (NgR1-Fc) was given to monkeys with spinal cord injuries. Researchers found that it was safe and seemed to help the monkeys regain some movement. The treatment also appeared to encourage the growth of nerve fibers in the injured area, suggesting a potential way to promote recovery after spinal cord injury.

Study Duration

4 months treatment, 7-12 months post-injury observation

Participants

16 adult female African green monkeys

Evidence Level

Level II; Experimental study in non-human primates

Key Findings

1
NgR1-Fc (AXER-204) administration showed no preclinical toxicological issues in healthy animals or safety concerns in spinal cord injury animals.
2
Treatment with NgR1-Fc led to significant improvements in both forelimb and hindlimb use in monkeys with cervical spinal cord injuries.
3
NgR1-Fc treatment resulted in a 2–3-fold increase in corticospinal axon density in the cervical cord below the level of the injury compared to the control group.

Research Summary

This study investigated the safety and efficacy of NgR1-Fc (AXER-204), a Nogo receptor decoy, in treating spinal cord injury in non-human primates. The results indicated that NgR1-Fc is safe for administration and shows promise in promoting functional recovery. Monkeys treated with NgR1-Fc demonstrated improved use of both forelimbs and hindlimbs, suggesting enhanced motor function after spinal cord injury. This functional improvement was correlated with increased corticospinal axon density below the injury site. The study provides crucial preclinical support for clinical trials of AXER-204 as a potential therapeutic intervention for chronic spinal cord injury, demonstrating both safety and efficacy in a relevant animal model.

Practical Implications

Clinical Trials for SCI

The findings support the advancement of AXER-204 into clinical trials for individuals with chronic spinal cord injuries, offering a potential therapeutic option.

Targeted Rehabilitation Strategies

The study suggests that combining NgR1-Fc treatment with rehabilitation strategies could further enhance functional recovery by promoting axonal growth and neural plasticity.

Future Research Directions

Further research could explore the potential benefits of NgR1-Fc treatment in conjunction with other therapeutic interventions, such as cell transplantation or electrical stimulation, to maximize recovery outcomes after SCI.

Study Limitations

1
The causative role of increased CST axon sprouting for improved function was not definitively demonstrated.
2
Only a single dose level of NgR1-Fc was tested, leaving open the question of optimal dosing strategies.
3
The study used continuous minipump infusion of NgR1-Fc, while intended clinical use will involve repeated bolus administration.

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