|Two weeks ago, one of my Parkinson’s patients told me that she had received “stem cell treatment” from a local “stem cell centre”. She was given some injections of “stem cells” into her shoulder muscles, which the centre claimed to be an effective treatment in improving the symptoms of Parkinson’s. Unfortunately, this lady’s physical condition did not get better, despite having spent RM 53,000 from her life’s savings.Three weeks ago, I received an email from another Malaysian Parkinson’s patient, whom I have known for a long time. He had stumbled upon a foreign website which claimed that its “stem cell” treatment had successfully improved the symptoms of some Parkinson’s patients. In order to support its claim, the testimony of the Parkinson’s patient was included in the website.These developments in “stem cell therapy” for Parkinson’s are valid reasons for concern, and thus the reason for this present article.
Parkinson’s is a brain disease which is characterized by death of brain cells in the certain parts of the brain which control body movement. In normal circumstances, these brain cells produce dopamine, a biochemical substance in the brain that is important for coordination of body movement. In Parkinson’s, the loss of these brain cells results in deficiency of dopamine, leading to symptoms such as tremor (uncontrollable trembling of hands), slowness of movement and body stiffness.
It is estimated that there are about 20000-25000 Parkinson’s patients in Malaysia. As most Parkinson’s patients are elderly people, the total number of Malaysian Parkinson’s patients is expected to rise sharply as the general population ages. Moreover, being an incurable and progressive illness, Parkinson’s results in relentless deterioration in physical disability. As such, Parkinson’s will become a major health burden in Malaysia very soon.
Cell therapy for Parkinson’s is not something new. Since 1987, aborted fetal brain tissues had been transplanted into the brains of Parkinson’s patients. The objective of cell therapy in Parkinson’s is to replenish the dying brain cells in patients, with the hope that the transplanted fetal brain cells will produce dopamine, and thus relieve the symptoms of Parkinson’s. Interestingly, the transplanted fetal brain cells have been shown to grow in the brains of Parkinson’s patients and lead to improvement in symptoms in some patients.
However, the initial excitement had died down when subsequent well-organized trials showed that the benefit of fetal brain tissue transplantation was not consistent, and might even lead to abnormal and uncontrollable body movement (Olanow CW et al, 2003; Freed CR et al, 2001). These studies showed that fetal tissue transplantation for Parkinson’s still has a very long way to go before it can be routinely recommended as one of the treatment options for Parkinson’s patients.
In view of the rather disappointing result of fetal tissue transplantation, and also the shortage of fetal tissue donors (related to ethical concerns), researchers have shifted their attention to stem cells.
Stem cells are “master” cells which can grow or transform into any type of type of cells of body tissue, e.g. blood, nerve, joints, muscles, etc. As such, stem cell treatment can potentially restore the function of organs in the body which are affected by various diseases, especially those which are incurable.
An advantage of stem cell is that it can be produced in large amounts and stored in the laboratory. In the case of fetal tissue transplantation, several fetuses are required for one patient.
There are several sources of stem cells. Embryonic stem cells (ESCs) are derived from early stage human fetus (a few days old) while adult stem cells (ASCs) are derived from adult tissues (e.g. skin). Induced pluripotent stem cells (IPSCs) are matured adult cells (e.g. skin) which are genetically “reprogrammed” to behave like “stem cells”. Unlike ASCs and IPSCs, there is a strong objection from religious groups who view ESCs therapy as a form of “killing”.
Nevertheless, regardless of the types of stem cells, the technique of stem cell treatment in Parkinson’s is highly complicated, and still at its infancy stage.
Many technical issues need to be resolved. Firstly, it is still uncertain which part of the brain is the most suitable place for injection of transplanted stem cells, in order to produce the optimal improvement of symptoms in Parkinson’s. What happens in the brains of Parkinson’s patients, which lead to the symptoms, is actually very complicated and not completely understood till today. Secondly, it can be difficult to ascertain that the transplanted stem cells will be capable of functioning in the same way as brain cells of Parkinson’s patients. Controlling the growth of the transplanted stem cells is also a challenge – in some cases, the transplanted stem cells have turned into tumors. Thirdly, the survival rate of the transplanted stem cells has not been satisfactory. Lastly, it has yet to be determined whether which type of stem cells (e.g. ESCs, ASCs) is the best for Parkinson’s patients.
Till today, there is no solid scientific evidence that stem cell treatment can be routinely recommended for Parkinson’s patients.
Nevertheless, some “stem cell centres” have prematurely recommended this treatment for Parkinson’s over the Internet. This has prompted the International Society for Stem Cell Research to issue a guideline (ISSCR 2008), which aimed to educate the general public on how to make decision when seeking stem cell treatments and also on the possibility of unproven stem cell treatment being marketed directly to patients.
Thus, the general public is advised to be cautious when contemplating stem cell treatment for Parkinson’s. I fully understand that most people who are suffering from an incurable illness would be tempted to try any treatment, regardless of whether it is scientifically proven to be effective or not. It is certainly the sufferers who feel the pain, and not the doctors or anyone else. I know that it is their sufferings or desperation which has strongly influenced their decision to seek an unproven treatment.
Nevertheless, I believe that the golden rule in medicine cannot be changed – that we should seek a specific treatment only when the benefit outweighs the risks. It is our duty as medical specialists to educate the general public on the best and safest treatment option which they should consider, in their best interest.
So, at this juncture, it is clear that stem cell treatment is still not ready for Parkinson’s.
How much longer do we have to wait? Nobody can be certain about the answer to this question. It can be 10 years, 15 years or more from now. We should be both hopeful and realistic.
Freed CR, Greene PE, Breeze RE, et al. Transplantation of embryonic dopamine neurons for severe Parkinson’s disease. N Engl J Med 2001; 344: 710–719.
International Society for Stem Cell Research. Guidelines for the clinical translation of stem cells. 2008.
Olanow CW, Goetz CG, Kordower JH, et al. A double-blind controlled trial of bilateral fetal nigral transplantation in Parkinson’s disease. Ann Neurol 2003; 54: 403–414.