By Dr. Mindy Aisen
The field of stem cell research offers enormous promise for the treatment of human disease. Stem cells are “undifferentiated” cells; they have the potential to develop into virtually any specialized type of cell in the body. So theoretically, stem cells might be used to regenerate human tissue or organs damaged by disease. There is hope that some day stem cells may provide effective restorative therapy for many human conditions, including those caused by damage the nervous system such as stroke, Parkinson’s Disease, spinal cord injury and cerebral palsy. At the present time, however, the field of stem cell research is in its infancy, and there are few effective uses of this type of therapy.
Stem cells can be derived in several ways. Embryonic stem cells (removed from early stage embryos) can be maintained in the laboratory and coaxed into differentiating into various cell types. Fetal cord blood contains human stem cells that can also be grown in the laboratory or frozen for later use. A recent technique for generating human stem cells involves obtaining cells from skin biopsies and “deprogramming” them into stem cells that can then be differentiated into various human cell types. The adult human brain contains viable neural stem cells; it may be possible to use medications to stimulate these natural stem cells into regenerating damaged brain tissue.
Stem cell scientists are currently working on the optimal conditions to maintain stem cells in the laboratory, the precise methods necessary to convert stem cells into the specific cells that might reconstitute damaged human tissues, and the techniques required to direct such cells to function effectively together. At the present time, much work remains to be done before the practical application of stem cells to the treatment of human disease becomes feasible.
In cerebral palsy, brain tissue is damaged at a very early stage of development: in utero, at or around the time of birth, or up until the age of 2 years. The brain is, of course, the most incredibly complex of all human organs. The brain consists of many different cell types interacting in a precisely organized fashion to produce the different aspects of thought and behavior in different brain regions. Before stem cells can be used to repair damaged brain tissue in cerebral palsy or any other brain disorder, scientists will have to discover how to turn stem cells into various specific types of brain cells, and induce them to form the precise connections and organization necessary for meaningful brain function. It is likely that stem cells converted into brain cells will have to be implanted in the precise areas that they are needed in order to provide effective treatment.
Specific Types of Approaches: Cord Blood Infusions
It is extremely unlikely that the administration of stem cells by peripheral infusion of cord blood can effectively treat cerebral palsy. Such cells have not been “taught” to form the necessary types of brain cells, and they will not be able to enter the brain, because there is an anatomic and physiological barrier which prevents certain medications and cells from reaching the brain, known as the blood brain barrier.
How can one explain the reports of improvements in the symptoms of cerebral palsy (CP) following cord blood infusions? Medicine is filled with such “anecdotal” reports of improvements when novel treatments are applied to chronic conditions. The symptoms of all chronic conditions fluctuate, and subjective factors, including the optimistic expectations that accompany novel therapies, often seem to alleviate disease manifestations. But in almost all cases, the underlying disease remains unchanged, and there is no meaningful long-term benefit. Indeed, in most cases, the risk of harm outweighs the chance of benefit when unproven novel therapies are used.
CPIRF strongly supports research into the use of stem cells to treat CP. But at present, CPIRF, in consultation with leading stem cell scientists, has reached the firm conclusion that use of cord blood or other forms of stem cell treatments for CP is inadvisable. Basic and applied research into various approaches to stem cell neural regeneration therapy must be vigorously pursued, and CPIRF will continue to fund such efforts. But at present, administration of cord blood to people with CP offers no meaningful chance of benefit.
Furthermore, the long term risks of cord blood infusions have not been studied, receiving infusions in other countries from donated cord blood may have significant risk and certainly present substantial financial strain for the families of those being treated.
We strongly endorse an organized scientifically rigorous initiative focused on rapidly identifying the most effective methods for using stem cell treatments to help repair the damaged brains of children and adults with developmental brain conditions.
Hello Dr. Aisen
Given encouraging results being conducted at Duke University (Dr. Kurtzberg) and numerous other published (granted, non scientific journal) results of individuals with CP and brain trauma having received autologous (one’s own) stem cell transplants, have you considered clarifying your position on stem cell transplants? Your write-up of December 2008 seems to specifically address allogenic (foreign cell) transplants but not autologous (one’s own cell) transplants.
Your position discusses allogenic transplants where of course there may be rejection risks. However, what are the risks of an autologous transplant? There is strong evidence that autologous transplants seem to have been beneficial for some patients. What is not known, is whether this is a statistical minority or majority of patients being treated. But, so what? If the risks of autologous transplant are negligible, even if a minority of transplants were an evident success, wouldn’t it be valuable for parents to consider this?
I’d be grateful for your thoughts.
Kind regards,
Eugenio Ramirez
I don’t understand the hesitation to use stem cells as a treatment for people with cp. These individuals, and their families suffer enormously, and not enough is being done to improve quality of life. It seems you have to meet a certain criteria in the US to even be considered for an exam, yet countries around the world are moving beyond the mental block that seems to prevent progress in America, and success is being reported in every case. I have 3 grandchildren with different levels of cp. The 9 year old is the most severe, not sitting, non-verbal, etc. However, very aware of his surroundings, and what is happening. I am preparing to get stem cell treatment this summer for all 3 of the children. We are not necessarily looking for a cure, but quality of life. I don’t see any reason not to go forward. I wonder if some of this uncertainty being spread is to keep things as they have been. Comfortable. You go to therapy, physical,speech, occupational. Wheelchairs, standers, braces, etc. are continued purchases. No one gets better, and everyone keeps their income. The thing that saddens me the most is the fact that I am going to have to travel outside the US to get the treatment that my grandchildren deserve. The money that I could be spending here, is going to be spent in another country. Time is not on our side. I can’t wait on the US to get through 30 more years of testing. Every day I wait is another day they are denied. Thank God, and the websites this treatment is available to those who don’t meet the guidelines in the US.