Spinal cord injuries can result in severe neurological dysfunction, including motor, sensory, and autonomic paralysis, and up until now there has been no cure or effective treatment for such injuries.
But the first human trial based on Nobel Prize winning induced pluripotent stem cells (IPSC) technology, is due to start in Japan, giving hope to hundreds of thousands of paralysed patients, that there might be light at the end of their tunnel.
What is the spinal cord
The spinal cord is responsible for relaying signals up and down the body from the brain to the nervous system. The spinal cord is a bundle of nerves contained in the spinal canal, which is cocooned in the spinal column (not to be confused with the spinal cord – they are two very separate entities).
The spinal cord itself has a protective sheath wrapped around it which acts as insulation whilst allowing nerve signals from the brain to travel even faster to where they need to go.
The spinal column is divided into five distinct sections:
- Cervical spinal cord
- Thoracic spinal cord
- Lumbar spinal cord
- Sacral spinal nerves
- Coccygeal spinal nerves
The site of the spinal cord injury will determine the severity of the injury and injuries are classified as either:
- Incomplete – An incomplete spinal cord injury is where the spinal cord is either partially severally or slightly damaged, allowing the injured person to retain some function or feeling below the site of the injury.
- Complete – A complete spinal cord injury is where the spinal cord is completely severed, thus eliminating the chances for any nerve signals to be transmitted below the site of the injury.
The higher up the spinal cord the injury occurs, the more function and feeling will be lost. It is estimated that approximately every year there are between 8 to 246 cases per million incidences of spinal cord injuries worldwide.
How can stem cells could cure paralysis
Stem cell therapy is amongst the most exciting ongoing research for people with spinal cord injuries, in modern medicine. Because whilst the research is still in its infancy, legitimate trials are showing promising results.
According to the Journal of the American Academy of Orthopedic Surgeons, there are different stem cells which have varying abilities to restore certain functions.
Stem cells are self-renewing cells that can differentiate into one or more specific cell types. For people with spinal cord injuries, stem cells could prevent further cell death, stimulate cell growth from the existing cells and even replace the injured cells, restoring the communication channels between the body and the brain.
Until recently, stem cell research has involved looking at:
- Mesenchymal stem cells. These cells are typically harvested from bone marrow and can be used to prevent inflammatory responses to injury that cause cell death.
- Peripheral nervous system stem cells. These cells secrete nerve growth factor that encourage cell growth and can act as temporary replacement cells.
- Embryonic stem cells. Although research into these is somewhat controversial, embryonic stem cells are resilient. Many of the animal studies that have been carried out show these stem cells limit the inflammatory response and encourage cell growth.
- Induced pluripotent stem cells. These stem cells are derived from adult skin cells. They are the newest stem cells to be researched. Early studies have shown these cells can offer similar benefits to embryonic stem cells, but without any of the ethical issues.
It is research into these induced pluripotent stem cells that the team in Japan are currently laying down the groundwork for. They are planning to conduct a first-in-human study of an induced pluripotent stem cell-based intervention, for subacute spinal cord injury.
Not only that, but it is the first such therapy to look into treating this kind of injury, that has ever received government approval for sale to patients.
However there are concerns by those who work in the field, but aren’t working on this particular project, that the evidence to support the suggestion that the treatment works, is insufficient. They state that the approval for the research was based on a small, poorly designed clinical trial.
Like the majority of scientific breakthroughs that have gone before, there will always be naysayers – we used to think the world was flat and the sun orbited Earth, that the body was composed of four humours and an imbalance in those made us sick.
Those theories were disproved, and look how far we’ve come since then. Now imagine if we could make a paralysed person walk again. It will happen. But for now, let’s celebrate and support this team for trying.
Because whilst there have been multiple attempts to develop stem cell transplantation approaches with the aim to regenerate damaged spinal cords before, this multicentre team is planning the first that might actually work, and be ethical to boot.