Mice Walk Again: Exploring an Alternative Approach to Spinal Cord Injuries
Historically, the medical approach for attempting to cure the incurable effects of tragic spinal cord injuries — such as in the case made famous by America’s classic super hero, Christopher Reeve — has been to affect regeneration of damaged nerves through stem cell therapy or by introducing growth factor proteins, like BDNF. Success with these applications has yet to be realized, as apparently the adult body’s resistance to re-growing its nerve centers is stronger than expected.
Recently, however, a team at Children’s Hospital Boston, lead by Zhigang He, has been developing an alternate approach to the problem. Instead of trying to force existing nerve fibers to regrow, or trying to introduce new cells to take their place, the group manipulates the communication in the cells to “turn off” an apparent gene that tells the neuron to stop growing. With the gene shut down, the neuron is free to generate and flourish as it sees fit.
They have found at least three proteins involved with the critical myelin coating of neuronal axons that actively work together to inhibit myelin growth. Blocking the proteins, either genetically or chemically, is being shown to promote the sprouting and regeneration of local structures in neuron networks.
The process is being tested in mice with spinal cord injuries by removing a special enzyme called PTEN that is activated in mature systems to limit cell growth. With the enzyme out of the picture, the cells think they are young again and start to grow. No controversial stems cells necessary, and no introduction of unnatural chemicals… just a process that involves removing a little key that is in the way. Of course, it would likely be important to be able to replace the key once the damaged cells have rejuvenated, otherwise a cancer-like state might be a drastic side effect.
Although this new therapy is far from ready for human trials, it is a wonderfully positive example of how significant advances in human improvement might come from looking at problems at a little different angle. These experimental mice are paving the way toward the coming acceleration in treatments for reversing many devastating human experiences, including widespread nervous system damage and degradation.
“Mice regain movement after spinal cord injury,” Scientific American Observations August 8, 2010
“PTEN deletion enhances the regenerative ability of adult corticospinal neurons,” Kai Lui, et al., Nature Neuroscience, August 8, 2010 Brief. Full article pdf.
“Spinal cord regeneration success in mice,” BBC News Health August 8, 2010 [