Chitosan implants for nerve regeneration

Artificial nerve conduits are used for peripheral nerve damage, but still have some disadvantages compared to autologous cells, such as lack of neurotrophic factors. In the presented study, a nerve conduit made of chitosan, collagen and Schwann cells is used to repair damage to the sciatic nerve of mice, thus providing a simpler alternative to the complex autologous nerve transplantation.

 

 

 

 

 

 

 

 

Takeya, H., Itai, S., Kimura, H. et al. Schwann cell-encapsulated chitosan-collagen hydrogel nerve conduit promotes peripheral nerve regeneration in rodent sciatic nerve defect models. Sci Rep 13, 11932 (2023). https://doi.org/10.1038/s41598-023-39141-2

Nerve tubes made from chitosan, collagen and Schwann cells help regenerate sciatic nerves in mice

When peripheral nerves are severed, most attempts are made to repair this damage without tension. In the case of larger gaps between the nerve endings, this is not easily possible, which is why autologous nerve transplants are used. However, these are very costly because the body's own cells have to be removed, propagated and re-implanted. Artificial nerve conduits are an alternative, but these lead to slower and poorer nerve regeneration due to the absence of fibrin, neurotrophic factors, and glial cells.

Schwann cells are a type of glial cells that help nerve fiber guidance during regeneration through band-like structures known as Büngner's bands. They also help to mitigate the disadvantages of artificial nerve tubes by secreting various messenger compounds.

To introduce the glial cells missing in previous nerve conduits, chitosan was used in the presented study. Chitosan can stimulate wound healing, which has been shown in numerous publications. Specifically for neurons, chitosan oligomers are known to promote axon regeneration. In addition, chitosan nerve conduits have already been successfully tested in clinical trials. The constructs used here consisted of an outer chitosan hydrogel layer and an inner collagen layer with enclosed Schwann cells. The collagen layer served mainly for stability. Since the degradation rate of the artificial tubes is also important for healing, chitosan is suitable because degradation can be very easily controlled via the degree of deacetylation, the size of the polymers as well as the concentration. You can find different chitosan specifications in our shop. In addition to these tubes, autologous implants as well as chitosan and Schwann cells were used individually to repair damage to the sciatic nerve of mice.

Results:

• the combination of chitosan and Schwann cells promotes axon regrowth, remyelination and restores motor abilities
• chitosan and Schwann cells individually promoted healing significantly less
• the artificial conduits still lead to worse regeneration than autologous cells, but are easier to produce
• due to the manufacturing method, the size of the tubes can be easily adjusted depending on the nerve
• ideal cell type for nerve regeneration is not yet known, but chitosan can help to introduce different cell types

Conclusion: In the presented study, chitosan and Schwann cells were successfully used to regenerate sciatic nerves from mice. Chitosan is well suited for artificial nerve tubes due to its adaptable decomposition rate and regenerative effects, and works particularly well in combination with cells.

Link to article: https://www.nature.com/articles/s41598-023-39141-2