Gabby Kulikowski
Dr. Kollmeier
A&P 1
December 17, 2013
Extra Credit: CNS nerve repair
For years, many have thought that nerve repair in the Central Nervous System was impossible, but studies have shown that by the use of different methods, the nerves can be regenerated over time. Some have used cell adhesion molecules and some have used biodegradable engineered scaffolds seeded with Schwann cells.
All of the injuries that would cause damage to the nerves of the CNS are spinal cord injuries. It is said by Restorative Neurology & Neuroscience that “Reconstruction of the lesion site, remodelling, and regeneration of axons require the interactions of cell adhesion molecules (CAMs) on neighbouring cells or with the extracellular matrix (ECM) to regulate cell survival, position, and the formation of new synapses, and to guide regenerating axons.” (2) The subdivision of CAMs is the L1 CAM, which is expressed in the axons of nerves during cell growth, helps with the regeneration because the axons form around the lesion site to upgrade the L1. The L1 CAM assists so much in the regeneration of nerves in “retinal ganglion cells, neurons in the thalamic reticular nerves, substantia nigra neurons, and neurons in brain stem and cerebellar deep nuclei.” (2) The L1 allows for the gradual repair of the nerve that was damaged because of its significant presence in the axon body and the growth of an axon. Allowing for the axon to grow is a major contribution to neuronal regeneration after injury to the CNS.
Another method that has allowed for neuronal regeneration after injury is biodegradable engineered scaffolds with Schwann cells. In the past, in order to regenerate damaged nerves in the CNS tissue transplantation and peripheral nerve grafting were used, but that would sometimes lead to immunoglobulin problems associated with disease and donor shortages. As stated by Neurochemistry International, “Biomaterial scaffold creates substrate within which cells are instructed to form a tissue or an organ in a highly controlled way… a scaffold is to direct cell behavior such as migration, proliferation, differentiation, maintenance of phenotype, and apoptosis by facilitating sensing and responding to the environment via cell–matrix and cell–cell communications. Therefore, having such abilities provides scaffolds seeded with a special type of cell as an important part of tissue engineering and regenerative medicine which spinal cord regeneration is an example of.” (1) These biomaterial scaffolds were seeded with Schwann cells and carried out in an experiment. Biodegradables can also be implanted as a structural scaffold and used for repair because they promote growth of the axon. (1) Implantation will work but the implant must be compatible with the nervous system that is receiving it. With the help of Schwann cells, the biomaterial scaffold will also promote growth in the axon. It has been proven that “Schwann cells also are capable of re-organizing the glial scar” of an injury to the CNS and reattach axons to the spinal cord where they were lost. (1) The best choice with the use of Schwann cells is to use a synthetic and natural polymer (biomaterial) to regenerate the spinal cord injuries.
Axonal growth when dealing with spinal cord injuries is crucial. If there is no axonal growth, then it is impossible to repair damaged nerves. When applying neuronal regeneration, other factors that promote axonal repair must come into the picture. Those factors such as cellular adhesion molecules (CAMs) and biodegradable scaffolds seeded with Schwann cells are more than beneficial to the repair of the CNS. Not only do they promote the growth of axons, but they also restore the nerve damage that occurs in spinal cord injuries.
LITERATURE CITED
1. Tabesh H, Amoabediny G, Nik NS, et al. The role of biodegradable engineered scaffolds seeded with schwann cells for spinal cord regeneration. Neurochem Int. 2009;54(2):73-83. doi: http://dx.doi.org.ezproxy.rowan.edu/10.1016/j.neuint.2008.11.002.
2. Zhang Y, Yeh J, Richardson PM, Bo X. Cell adhesion molecules of the immunoglobin superfamily in axonal regeneration and neural repair. Restorative Neurology and Neuroscience. March 1, 2008(26):81-82-96.