Currently there is no treatment for recovering human nerve function after injury to the brain or spinal cord because central nervous system neurons have a very limited capability of self-repair and regeneration.
Regeneration in the central nervous system requires neural activity, not just neuronal growth factors alone. Chemical neurotransmitters relay, amplify and modulate signals between a neuron and another cell.
Researcher Yadong Wang, assistant professor, Coulter Department of Biomedical Engineering, Georgia Tech and Emory University, reports that integrating neurotransmitters into biodegradable polymers results in a biomaterial that successfully promotes neurite growth, which is necessary for victims of central nervous system injury, stroke or certain neurodegenerative diseases to recover sensory, motor, cognitive or autonomic functions.
The researchers feel their technique has a potentially promising strategy for encouraging the regeneration of damaged central nervous system cells—or neurons. Wang, and graduate student Christiane Gumera, developed novel biodegradable polymers with flexible backbone that allowed neurotransmitters to be easily added as a side chain. In its current form, the polymer would be implanted via surgery to repair damaged central nerves.
The goal is to create a conduit for nerve regeneration that guides neurons to regenerate, but gradually degrades as the neurons regenerate so that it won’t constrict the nerves permanently. The researchers found that adding 70% acetylcholine to the polymer induced regenerative responses similar to laminin, a benchmark material for nerve culture. The 70% acetylcholine also led to a neurite growth rate of up to 0.7 millimeters per day (about half the thickness of a CD disc).
The researchers are currently investigating the mechanisms by which the neurons interact with these polymers. Since neurons that remain intact after severe injury have only a limited capacity to penetrate the scar tissue, these new findings in nerve regeneration could help compensate for the lost connections.
This approach is not limited to nerve regeneration. Researchers note that it can probably be used for other neurodegenerative disorders.