What are they?

Most of the cells in our body have specialised to have a specific function, for example liver cells have specialised to store proteins and to modify and excrete substances in the body. Neurons are electrically excitable cells in the nervous system which transmit messages from the brain to the rest of the body.

Stem cells are different because they are early precursor cells which can reproduce themselves, and they have the potential to specialise and become other cells, like cells in muscle, blood or the brain.

Embryonic stem cells are from part of the early 4 - 5 day embryo or the 5 - 10 week foetus. They are pluripotent, which means they can give rise to all types of cells of the body.

Adult stem cells are can be found in some parts of the body like bone marrow, brain, and retina of the eye. Also, umbilical cord blood is a source of blood-forming stem cells, similar to the cells obtained from bone marrow. Adult stem cells are multipotent, capable of turning into a limited number of cell types. Some research suggests these are not as effective as embryonic stem cells when used for research purposes.
 

What do they do?

Stem cells might be able to repair or replace damaged tissue in the body. The most realistic aim for stem cells would be the repair of MS damage in the central nervous system through re-growth of myelin and protection of nerve fibres. Stem cells might also be used to replace the immune system (thought to mis-fire in MS) and in that way prevent further damage in MS.  

Do they work?

Research into adult stem cells being used to repair myelin is being carried out at the MS Society funded Cambridge Centre for Myelin Repair and the Edinburgh Translational Research Centre.

More information about the MS Society Cambridge Centre for Myelin Repair

Stem cells might also be able to replace the immune system (thought to mis-fire in MS) and in that way prevent the damage in MS. Some work has been carried out using bone marrow (stem cells) to replace the immune system in a multi-centre European initiative (ASTIMS trial). These studies are in phase III clinical trials and will last at least 6 years involving 30 people with MS.

They involve using strong drugs (the same as those used in chemotherapy) to knock out the body’s immune system and then the person’s bone marrow is replaced (using the persons own preserved bone marrow stem cells) in order to replace the immune system. Since the immune system is mis-functioning, it is hoped this should prevent further MS damage. The results of this trial are expected in 2010-2011.

Another trial which has begun at Bristol's Frenchay Hospital will test bone marrow stem cell therapy with a group of six MS patients. The aim of the trial, conducted by North Bristol NHS Trust and the University of Bristol, is to find out what effects, good or bad, it has on people with MS, and their disability. This is a small early stage trial.

Another trial beginning soon at the University of Cambridge will assess the safety of a bone marrow stem cell transplant as a treatment for optic neuritis in people with MS.
 

Should I take it?

There are several risks associated with stem cells which must be overcome before they can be used as a treatment. For example, in cells which have unlimited capacity for self-renewal and growth, there is a risk of tumour formation.

Stem cell transplant treatment is controversial because of significant side effects and even death and clinical trials are continuing in people with very severe forms of MS for whom there are few treatment options. It is important to note that these trials are conducted in fully controlled scientific and clinical settings with a high regard for patient safety and with full medical resources at hand. Also, importantly, the people with MS are not asked to pay large, or any, sums of money to be involved in the trials. Any stem cell treatments which are offered under different terms, outside of a clinical trial should be regarded with concern. Anyone considering stem cell treatment for MS should consult their GP, neurologist or MS nurse as a matter of urgency.

While stem cell research holds exciting possibilities it is still in very early stages. There is some way to go before these cells are fully understood and used to treat MS.