Under the microscope: What can stem cell science do for MS?
What are stem cells?
Most cells in our body carry out very specific roles. For example, red blood cells carry oxygen around the body, while nerve cells send messages to each other. These are called specialised cells.
Stem cells are different because they aren’t specialised. This means they have the potential to become lots of different types of cell. They’re really important during development, and can also repair damage and replace cells as we age.
Haematopoietic stem cell transplantation (HSCT) to reset the immune system
HSCT aims to replace the misfiring immune system with a normally functioning one. This is done with chemotherapy which kills off the old immune system. New haematopoietic stem cells, which make all our blood, cells, including immune cells, are then given to the patient.
Clinicians in London and Sheffield, often working closely with international colleagues, are currently exploring this approach with considerable success.
While still not a ‘routine’ treatment, our increasing understanding of the potential benefits and clinical risks of HSCT mean it is available on the NHS for those who could benefit.
Experimental mesenchymal stem cell therapy (MSCT) to limit the damage
Animal research suggests that mesenchymal stem cells can help protect the nerves from immune attacks, and may also be able to promote myelin repair. We think they do this by releasing chemical factors that benefit other cells.
As a therapy MSCT is still early on in its development. But large phase 2 clinical trials are underway. These include the international MESEMS study, the UK arm of which is being run by Professor Paolo Muraro at Imperial College London. The ‘Actimus’ trial in Bristol is testing MSCT for people with primary and secondary progressive MS. Both trials are fully recruited and due to report in 2019.
Over the next few years we expect to know whether MSCT can have a lasting effect and make a genuine difference for people with MS.
Neural stem cells to promote myelin repair
Neural stem cells live in the brain and produce nerve cells and myelin-making cells, called oligodendrocytes.
Researchers in Cambridge are looking at whether injecting neural stems into the central nervous system could be an effective way to increase myelin repair. Although this is one of the earliest suggested uses of stem cells for MS, it’s still the most experimental and the furthest from the clinic.
Perhaps the most exciting prospect is kick-starting our own neural stem cells to help the brain repair itself. Researchers are studying how neural stem cells promote myelin repair so that they can find drugs that can boost this process. One such drug (bexarotene) is now in clinical trial.
Stem cells as a research tool
As well as investigating adult stem cells, researchers are now able to make embryonic-like stem cells in the laboratory, known as induced pluripotent stem cells. This amazing technology is helping our scientists study MS in live human tissue.
This blog was adapted from articles that first appeared in Research Matters magazine. We are particularly indebted to Neurologist Professor Neil Scolding, from the University of Bristol, for his expert insight into the use of stem cells for MS.