Sunday, 26 October 2014

Reversing Paralysis - Spinal Cord Regeneration

This week (in the UK) there has been a very interesting story in the news - A man in Poland has been able to walk after surgery to repair his spinal cord. He had been paralysed from the chest down after a knife attack in 2010.

You can read the news story here:

This was featured in the BBC Panorama program, which you can watch on the BBC iPlayer until Oct 2015:

I watched the program after hearing about the story on the news, with a thought that this may yield a treatment for HSP. Here is my take on the story (as presented on Panorama).

Researchers had identified that the olfactory system (sense of smell) was the only system in the human body where nerves were continually regenerated throughout life. In all other systems nerves, once damaged, do not re-grow.

Much research has been done over many years to identify if the olfactory cells could be used to encourage re-growth in other nerve systems, with work being undertaken at UCL (University College London) -  Professor Geoffrey Raisman featured on the program. They had undertaken research with mice which had shown potential. Olfactory ensheathing cells (OECs) were shown to regenerate the olfactory nerves, and the research involved extracting these cells and transplanting them to examine if they would regenerate other nerves.

The research had concluded that the cells needed to be extracted from the olfactory bulb, which is located in the brain. This means that very invasive surgery is needed to extract them - the program didnt go into the details of the cell extraction.

A team in Poland, led by Dr Pawel Tabakow of Wroclaw Medical University, was keen to take this further. Darek Fidyka had been paralysed from the chest down after a knife attack in 2010. He volunteered to undergo the surgery to extract the cells from his olfactory bulbs. These cells were then grown in the lab for a couple of weeks before being injected into the spinal cord at the injury site.

The story showed the operation to implant the cells into the spinal cord. The damage site was bigger than expected from the various MRI scans - half an inch (10-15mm) rather than a nice clean slice. There was a small section of cord which was intact, but most of it had gone in the attack. The view was that whilst the cells would encourage nerve re-growth they would not bridge this gap, so a section of nerve from the ankle was inserted to form a bridge. Some cells were injected into the section of the cord which remained, but most were injected into the spinal cord either side of the bridge. They were only able to extract a very small amount of these cells, which remained a small amount even after 2 weeks growth in the lab. It was quite amazing to see the surgery.

The surgery was undertaken in 2012. After a few months intense physiotherapy there was some activity, and this developed over the next two years such that there was muscle re-growth, control from the brain and the brain was receiving feedback - i.e. there was re-establishment of 2-way communication through the spinal cord. Darek was also able to regain some bladder, bowel and sexual function again. After two years he was able to walk again and is able to drive.

This is one example. The research had been conducted to demonstrate that the surgery and cell implants had done the job, although there is still some scepticism. The next steps for this research is to repeat the process in a few more patients which give a much more robust dataset to demonstrate that it works.

The story mentioned that the results were published, so that the scientific community can scrutinise them. That article (or at least an abstract for it) can be found here:

My take on the key points are:

  • Invasive surgery is needed to extract the cells
  • Invasive survey is needed to inject the cells into the spine
  • The procedure was shown to work at a small site where there was relatively clean damage of the cord
  • Other sections of nerve can be used to act as a bridge to replace missing parts of the spinal cord
  • It is a long and hard process getting movement back
  • The repair seemed to have benefits in other lower body functions

So the question I consider is: how likely is it, given that our spasticity is like paralysis, that this kind of treatment could be used for HSP?

My understanding is that the degeneration of the nerves in HSP is along the nerves rather than across them, and they degenerate from the end, rather than at a place mid-way along the spinal cord. The main problem, from my limited understanding, is that in HSP the nerves degenerate from the end, so I suspect that even if a long piece of nerve could be used to bridge over the degenerated area of the spinal column the issue will be that the join between the upper motor neurons and lower motor neurons would still be missing. So my suspicion is that unless a "bridge" can be created between upper and lower motor neurons, this is unlikely to help people with HSP in the short term.

However, the program was keen to point out that this effectively showed proof of concept, and that the researchers were keen to share their knowledge. This may mean that the technique or the knowledge may be used to help understanding or provide new ideas for treatment. The comparison was made in the programme with antibiotics - we take these as a given now, but re-wind about a hundred years (to 1928) and Alexander Flemming first discovered the antibiotic effects of Penicillin. Now we have many many more antibiotics which are much more powerful than Penicillin, but that was the starting point. Perhaps that kind of path can follow from this process.

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