Stem cell therapies and neurological disorders of the brain: what is the truth?

24 Apr 2013
Roger Barker

There have been several claims that stem cells can already be used in patients affected by neurological disorders. What do we really know about these therapies and how should these claims be viewed?

There is a great deal of excitement about the possibility of using stem cells to treat currently incurable diseases of the brain - whether these be late onset neurodegenerative disorders like Parkinson’s disease (PD), younger onset inflammatory diseases such as multiple sclerosis or even conditions in which there is an inborn error of metabolism. Whilst this excitement is understandable, it is all too easy for it to spill over into unfounded optimism and with this, the premature translation of therapies to the clinic, where desperate patients and their families will often seek to try any new therapeutic intervention.

Replacing cells in the brain: What do we know about stem cell therapies for neurological disorders?

To begin with it is important to understand what stem cells we are talking about and what we’re trying to achieve by using them  disease conditions. For example in the world of haematology, stem cells transplants have been around for years as they can be used very effectively to replenish the bone marrow of patients who have been treated for a range of cancerous blood disorders. In this case, the idea is simple - you remove all the cells, including the malfunctioning and cancerous ones, and then rebuild the system using new unaffected stem cells. In the case of disorders of the brain this is one approach that is commonly adopted in research towards treatments:to use stem cells to replacethe neural (brain) cells that are already lost as part of disease process, such as the midbrain dopamine cells in PD. However, to do this you first of all have to show that:

  • your stem cells can make authentic replacement neurons of the type you want (nigral dopamine cells with PD; striatal DDARP-32 projection striatal neurons in Huntington’s Disease etc);
  • the properties of these stem-cell derived neurons can be reproducibly demonstrated in the laboratory (and ideally more than just one laboratory), both in the dish and in animal models of disease;
  • the neurons can survive long term in animal models of disease and have functional benefits to that animal; and
  • all of this can be done without evidence of cell overgrowth or transformation into malignant (cancerous) cells within the transplant.

To date the need to achieve all this has only been met in part for neurons derived from embryonic stem cells or iPS cells, and even then the data is not of a quality to merit clinical trials. The problem is that, whilst the cells that can be made in the lab look like the ones needed, they often lack certain vital characteristics. For example cells that look like the dopamine nigral cells needed to treat PD can be made, but they don’t display the proper fibre outgrowth and integration into the host neuronal networks that would be necessary for them to function in a brain. Without this, the cells lack true authenticity and cannot be expected to be able to help patients if transplanted.

In the case of other types of stem cells (e.g. mesenchymal stem cells) the evidence that they can form true neurons of the type needed for treatments is even more questionable.  It is no longer acceptable to say that cells are neurons because they “look like” them. They need to be shown to not only “look like neurons” but to have all the key properties of neurons and to function as neurons: they must be electrically excitable, release the appropriate neurotransmitter, have all the right genetic markers switched on, make neural structures like processes and synapses and have a functional effect in models of disease. At the moment, extravagant claims are made using cells such as mesenchymal stem cells, based only on very limited characteristics of the cells they produce. And these are claims that will allow for unsubstantiated clinical trials.

How else might stem cells be used in neurological disorders?

Of course stem cells do  not only have to be used to make replacement neurons for transplantation. They could be used in other ways, in particular as a supporter of diseased cells and a controlling or adjusting influence within the patient’s central nervous system. Indeed many cite this as a reason why some types of stem cells (e.g.mesenchymal stem cells) may be uniquely helpful in disease. For example, in multiple sclerosis such stem cells transplants may be of value not only in producing substances that support the survival or recovery of  damaged neurons, but through reducing inflammation. This may prove a valuable approach irrespective of any ability of such stem cells to turn into replacement neural cells. As such, much work has been done with stem cells of this type in the laboratory but at the present time it remains unproven that they work in any neurological condition.This is not to say that good quality research is not taking place in this area. Indeed, a number of properly funded, well formulated studies have been done in small numbers of patients to show that this approach is feasible and well tolerated.

However these careful and thorough trials get lost in the mass of other studies which have appeared on the web (rarely in scientific peer reviewed papers) claiming remarkable benefits from stem cell therapies in a wide variety of disorders (including, but not restricted to neurological disorders). These studies often involve private clinics where the pre-clinical (i.e. laboratory) data supporting the use of their cells is lacking, leading to clinical trials which lack rigour and credibility.

"Any experimental therapy has to follow a well established route if it is to be recognised as being of value"

How can safe and effective treatments be developed?

The development and translation to the clinic of any experimental therapy has to follow a well established route if it is to be recognised as being of value. First it must be shown in the laboratory that the approach works and HOW it works before it can even be considered for clinical use. If it can be shown pre-clinically to be safe and effective, then it next needs to be tested in a small number of patients in a properly funded phase I clinical trial, where the primary aim is to check that the therapy is well tolerated and safe, though it may be possible to observe some sign of an effect. Patients entering such studies should not have to pay to be a part of the research and it should be funded through appropriate research funds, not public health structures. If such a study shows the therapy to be safe with some suggestion of a possible effect, then a bigger funded phase II study can be undertaken to see if that effect can be better quantified and more information gained on safety. Again this should be properly funded and not rely on patients being able to afford it. Only then can a proper trial be done to see whether the therapy really has benefits over what else is out there for that condition. And then, and only then, can the more definitive studies be planned, the outcome of which will determine if the treatment should become more mainline medical therapy. All of this takes many years and should evolve outside of any funding from patients or national healthcare systems. For many patients waiting for this process to be completed is not a luxury they can afford, as they have the incurable condition for which these therapies are being developed. They are desperate to try anything and it is this vulnerability that is exploited by many clinics around the globe offering unproven stem cells therapies. As a result, many patients are exposing themselves to treatments that have no basis for effect and which also have the potential to kill them.

The truth of therapies today

So what is the truth of stem cell therapies for neurological diseases? The truth is that the field is moving forward every year and small, well thought out clinical trials are being planned and undertaken, but to date none have shown  a level of effectiveness that gives hope they may be useful as mainline therapies in 2013. With time, progress will be made, but it is only by following the well established methods of translation from the laboratory to the clinic that this can happen. If such approaches are abandoned in the rush to get to clinic, then there is a very real risk that the whole field will be derailed by a disastrous result of an ill thought out treatment. If this were to happen then those therapies being developed using sound scientific principles and which promise to be of a great use in the future, will instead be lost forever as the unproven, commercially driven cells of today confuse and kill the field.

Related links


Lead image of neuron Copyright 2005 Nicolas P. Rougier, released under the GNU General Public Licence.

Stem cells


My child (1 year and 8 months old) is sufferenig from cerebral palsy. He doesn't smile and he can't Identify anything. Is there any sort of a solution for this. Thanx a lot.

Your enquiry about cerebral palsy


Thank you for you for getting in touch, I'm sorry to hear about your child's condition.

EuroStemCell are an online information service and are not directly involved in treatments. We can't give you spefic advice about treatments but we can point you to some of our online fact sheets:

I hope this is helpful. If you ave further questions, do get in touch via our contact form:

Best wishes,


dementia problem

My father is diagnosed with dementia because of few cerebral brain attrophies attrophy in cerebellum is shown ..should we go for stem cell therapy or not ??

Your enquiry about dementia

Dear Sanjeev,

Thank you for your comment, I'm sorry to hear of your father's illness.

EuroStemCell are not directly involved in any research or treatments. Unfortunately we are unable to give specific advice about treatments or clinics.

Stem cell therapies are generally at an early stage of research and development. You may be interested in our fact sheet 'What disease and conditions can be treated with stem cells?', as it gives a good overview of treatments which are currently proven and available.

If you would like more information, please get in touch via our contact form:

Best wishes,


stemcell treatment

Hi there, I reccently had neurosurgery for epilepsy and i woke up with Homonymous Hemianopia, Do you think Stem cell treatment could possibly get my vision back?

Your enquiry about hemianopia

Dear Brenton,

Thank you for commenting, I am sorry to hear of your condition.

Stem cell therapies are generally at an early stage of research and development. A lot of research is underway to develop treatments for various types of eye conditions, but few proven therapies are available. You may find the following information useful:

If you would like more information, feel free to get in touch via our contact form: 

Best wishes,

Barbara Melville

Hi I am 14 years old and I


I am 14 years old and I wanted to learn more about stem cells and I found your site. I just want to thank you because of your good informations. I want to know if we get the gen that is the factor of building neurons out of the embryo from uterus, can we make neurons separately in laboratory?  I think if we could do that, when someone needs neurons we can make them with that person's gen combined with the embryo gens and the neurons will be produce for that person and then we can replace the new cells instead of old ones.


Your enquiry about neurons


Thank you for commenting. We're glad you're enjoying using the site!

 Embryonic stem cells come from a cluster of cells – called a blastocyst - at the very beginning of embryonic development, before implantation in the uterus. For fertility treatments blastocysts are produced in the laboratory, and if they are not used for a pregnancy they can (in some countries) be donated for research. There’s more information about where embryonic stem cells come from, and what they can do in our fact sheet: and on our embryonic stem cells topic page:

Embryonic stem cells have the potential to develop into any of the cell types found in the body; red blood cells, liver cells, muscle cells and even neurons. Different genes will determine which cells the embryonic stem cells will differentiate into. By knowing which genes determine which cells are created, scientists can take embryonic stem cells in the lab and turn them into different cell types, such as neurons. You can learn more about this in the short film “From embryo to brain cell”

As for the replacement of neurons in patients, there is still a lot to be done, but it’s an area that many researchers are working on. You can find out more about progress in different disease areas in our neurological disorders topic page:

I hope this information is of some use. If you would like more information, please get in touch via our contact form:

Best wishes,

Barbara Melville

Stem cell treatment

hi there my boy is almost one year old. the doctors say that he has a little bit of brain damage and because of this he is blind.we are awaiting the mri scan.

Would he be eligeble for clinical trails or maybe someone can give a doctor i can phone maybe a hospital any thing please.

We live in south africa if there is any information please.

thank you very much


your reply

Dear Lize, Thank you very much for your comment, I am sorry to hear of your son's condition. I recommend you read our article on stem cells and neurological disorders: If you would like more information, do not hesitate to get in touch via our contact form: Sincerely, EuroStemCell.

Brain stem cell


I want to ask about stem cell for brain damages such as brain idema , will be useful in this situation? Where can I found a center or hospital which can help us with stem cell treatment ?! 

Hello, and thank you for your

Hello, and thank you for your enquiry. In general, stem cell therapies are still at an early stage of development and more research needs to be done before they can be used for brain repair. You might find some useful information in our factsheets and the FAQ: What diseases and conditions can be treated with stem cells. I'd also recommend the ISSCR website A Closer Look At Stem Cell Treatments. Unfortunately, we are not able to offer advice on specific clinics or treatments.

If you have further questions, please feel free to get in touch with us using our enquiry form

All the best, Christele

about stem cell is usefull for physicall challenged patients








Your question about stem cells for physical conditions

Thanks for getting in touch, I'm sorry to hear that someone you care about in unable to speak or move. 

I'm very sorry to tell you, but there are no stem cell therapies available to treat this type of condition at the moment. Have you seen our information on 'What diseases and conditions can be treated with stem cells?' You can read it here: It gives a good overview of what stem cell treatments are currently proven and available.

If you have further questions, please do get in touch by email using our Contact form at and we will do our best to provide a more detailled response.With best wishes to you and your loved one,Emma

Stem Cells

thank you for the information ; I would appreciate if there are some seminar during the months of July or August in Europe

Your question about seminars in Europe


Thanks for your comment. Whenever we hear of conferences or seminars in the stem cell field, we add them to our Events calendar. There are lots of relevant events listed there so click on the link and take a look around. You'll see a number of conferences listed in July and August, and event organisers do upload details of their events here as they become available so keep an eye out for updates.

I hope that helps,