The online version of the journal Nature publishes an article today about a potential breakthrough in the treatment of spinal cord patients. While I do not have access to the full article, medicalnewstoday.com provides an overview of the research work. The highlight is that the researchers from Case Western Reserve University School of Medicine were able to restore breathing in rodents with spinal cord injuries.
This research provides optimism for similar success in humans (clinical trials with humans are hopefully forthcoming). In the recently released studies, the scientists combined “…an old technology a peripheral nerve graft, and a new technology an enzyme” to be able to restore 80-100% of breathing function in the rodents.
Using a graft from the sciatic nerve, surgeons have been able to restore function to damaged peripheral nerves in the arms or legs for 100 years. But, they’ve had little or no success in using a graft on the spinal cord. Nearly 20 years ago, [Jerry Silver, professor of neurosciences at Case Western Reserve and senior author,] found that after a spinal injury, a structural component of cartilage, called chondroitin sulfate proteoglycans, was present and involved in the scarring that prevents axons from regenerating and reconnecting. Silver knew that the bacteria Proteus vulgaris produced an enzyme called Chondroitinase ABC, which could break down such structures. In previous testing, he found that the enzyme clips the inhibitory sugary branches of proteoglycans, essentially opening routes for nerves to grow through.
In this study, the researchers used a section of peripheral nerve to bridge a spinal cord injury at the second cervical level, which had paralyzed one-half of the diaphragm. They then injected Chondroitinase ABC. The enzyme opens passageways through scar tissue formed at the insertion site and promotes neuron growth and plasticity. Within the graft, Schwann cells, which provide structural support and protection to peripheral nerves, guide and support the long-distance regeneration of the severed spinal nerves. Nearly 3,000 severed nerves entered the bridge and 400 to 500 nerves grew out the other side, near disconnected motor neurons that control the diaphragm. There, Chondroitinase ABC prevented scarring from blocking continued growth and reinnervation.
“All the nerves hook up with interneurons and somehow unwanted activities are filtered out but signals for breathing come through,” Silver said. “The spinal cord is smart.”
Three months after the procedure, tests recording nerve and muscle activity showed that 80 to more than 100 percent of breathing function was restored. Breathing function was maintained at the same levels six months after treatment”
This could be life-changing for those spinal cord injury patients who currently need ventilators to survive. If human studies prove the efficacy of such treatment, patients would have the hope of being able to breath on their own again. Not only would this dramatically improve these patients’ quality of life, but it would also provide a dramatically improved outcome for these patients. Currently, “[r]estoration of breathing is the top desire of people with upper spinal cord injuries. Respiratory infections, which attack through the ventilators they rely on, are their top killer.”
The BBC is reporting that “[r]esearchers hope to begin trials in humans. They are also investigating whether bladder function can be restored, which can be lost when the lower spine is damaged.”
The CDC’s most recent statistics, which are a few years old, suggest that there are currently about 200,000 people in the United States who are living with spinal cord injuries. This number increases by approximately 12,000-20,000 new patients annually. If some portion of these individuals could be provided hope for breathing on their own and or regaining bladder function, their lives could be dramatically improved.