Should we abandon Embryonic Stem Cell Research?
April 2, 2009 by Ryan Ward
By Ryan Ward, Kevin Graham & Ian Clarke
Stem cells can be derived from many adult organs- for example the stem cells derived from the blood and the nervous system. These cells have tremendous capacity/potential to treat once incurable diseases. The best treatment for some forms of leukemia remains a bone marrow transplant from a healthy donor after completely erasing the patient’s bone marrow (and hopefully any leukemia cells). This technology has been around for many years, and is now being applied to other diseases such as multiple sclerosis and is based on using healthy adult stem cells to replenish the diseased blood of a patient. The same can be said for neural stem cells of the central or peripheral nervous system, though for clinical application these cells remain unproven. The idea here is that adult neural stem cells could be harvested from a patient, or donor, and used for the treatment of spinal cord injury, or neurological diseases such as Parkinson’s.
Due to the success/potential of these stem cell therapies, the idea that embryonic stem cell research is no longer required is being promoted in comments posted on this blog, and on many others that discuss stem cell research.
Critics argue that, all current stem cell based treatments use adult stem cells, demonstrating that embryonic stem cells aren’t needed for today’s therapies. More importantly, they advocate that even if adult stem cells are deficient in some way, there now exists reprogramming technology where mature cell types (like skin fibroblasts) can be changed to induced Pluripotent Stem (iPS) cells which behave in many ways like embryonic stem cells. Proponents of this position argue that this discovery means that iPS cells can be substituted for embryonic stem cells in any current or future therapy. Following the example above for the treatment of spinal cord injury or Parkinson’s disease, iPS cells can be made from the patient’s own skin cells, reprogrammed into neural stem cells, then potentially used for therapy. They state, accordingly, no embryonic stem cells need be used, ever, for research or therapeutic purposes, for any disease.
On the surface this is a reasonable argument, one which many people are inclined to support. But it comes with some significant concessions which undermine the basic premise of this argument.
The first is that current adult stem cell and iPS cell technologies are largely based on research using embryonic cells. For example, therapy utilizing adult blood stem cells (like bone marrow transplants) would not exist without understanding how the blood system develops and operates - work done with human embryonic tissue dating back as far as the 1800s. Similarly, iPS cells would not exist if not for our understanding of human embryonic stem cells, and the factors/techniques required to support their growth. So the first concession must be that embryonic stem cell research HAS had a major and beneficial impact on our current medical technologies, and without research using embryonic cells we would not have the knowledge needed to use adult stem cells or iPS cells in medicine.
The second concession has one of two components: either the belief that we currently know everything of value that we will ever know from embryonic stem cell research, or that iPS cells and embryonic stem cells are totally and completely equal, in every aspect. Fundamentally, there can be no other SCIENTIFIC argument for abandoning their study, unless there is there is nothing else to learn from their use, or something completely equivalent can be used as a substitute.
No reasonable argument can be made to suggest that there is nothing else that can be learned from studying embryonic stem cells, but what about the argument regarding the substitution of iPS cells?
Dr. Yamanaka is a world expert when it comes to iPS cell technology. His lab was the first to report the generation of iPS cells from both mouse and human skin cells. In his analysis of human iPS cells, he reported that the difference between skin cells and embryonic stem cells is, at least, a five-fold difference in the expression of ~6000 genes. This result means that dramatically changing the expression level of at least ~6000 genes is the difference between skin cells and embryonic stem cells. Interestingly, when the same analysis was applied to iPS cells and embryonic stem cells, they discovered that at least ~1200 genes showed five-fold differences in gene expression levels. This means that over 1000 genes expressed by iPS cells are expressed differently in embryonic stem cells. Clearly then, the anti-stem cell research position must concede that iPS cells are not identical to embryonic stem cells in their gene expression profile, and one might wonder in what other ways the two cell types differ. This is a fundamental principle in all scientific research. No experiment can be interpreted without the proper controls. The only way we will ever be able to understand the differences between iPS cells and embryonic stem cells is to use both types of cells and compare them to each other.
Adult stem cells are valuable for research and therapeutic purposes, and their clinical application must be pursued for every possible disease. iPS cells are a burgeoning and promising field and their use in medicine and research must be supported in every way, but they are not currently a substitute for embryonic stem cells. Further, the technologies that support the therapeutic application of adult stem cells and iPS cells are based largely on embryonic stem cell research, and it remains unknown which cell type will be most applicable for treating different types of disease.
You might ask yourself the following questions: What if in the 1800s we had abandoned the research which revealed how the blood system develops; would we currently have the knowledge to perform bone marrow transplants for the treatment of leukemia? Or would we be dependent on radiation and chemotherapy which, all too often, fail to cure the disease? Similarly, if we forsake embryonic stem cell research today, what future therapies might never have the opportunity develop in the next 100 years? Of course time will tell, but one fact is certain: if we abandon the research, we will never find ways of using it for therapeutic purposes.
Comments
4 Responses to “Should we abandon Embryonic Stem Cell Research?”
Got something to say?
By using this site you agree to the Connecting for Kids terms of use. Click here to review the Terms of Use guidelines for this site.
Rett Syndrome and induced Pluripotent Stem cells goes “Green”
June 17, 2009 by Aaron Cheung
Stem cell researchers at The Hospital for Sick Children have now devised a method, reported in the scientific journal Nature Methods, that will facilitate the generation of induced Pluripotent Stem (iPS) cells. I have previously blogged about the promise of iPS cells (see related articles). iPS cells are cells which have been reprogrammed from a differentiated somatic cell (such as your skin cells) to a pluripotent stem cell (like an embryonic stem cell, only that you don’t need to use embryos!). The generation of iPS cells is inherently very rare which occurs at a frequency of about 0.01% meaning you can generate about one iPS cell line out of hundred thousand cells. Out of which, many lines fail to satisfy the different rigorous tests necessary to be given the prestigious name of “iPS cell”.
A group led by Dr. James Ellis, and lead author Dr. Akitsu Hotta, at The Hospital for Sick Children has generated a reporter, named EOS, that will facilitate the generation of iPS cells for both mouse and human. The reporter has DNA elements (called promoters) that will drive the expression of a fluorescent protein (GFP) and an antibiotic resistance gene (puromycin) that will only turn on in pluripotent stem cells, but remain off in differentiated cells. Therefore, scientists can now generate iPS cells from different sources and the iPS cells will literally “light up with a green colour” once reprogramming has been achieved. Furthermore, by adding puromycin to your culture, it will keep the iPS cells in a pluripotent state as iPS cells will normally spontaneously differentiate.
To demonstrate the applicability of EOS, Ellis also derived iPS cells from patients who have a neurodevelopmental disorder called Rett Syndrome. Rett Syndrome is an Autism Spectrum Disorder which affects almost exclusively females at an incidence of 1 in 10,000 and is one of the leading causes of mental retardation in girls. These Rett Syndrome iPS cells were green when placed under a fluorescent microscope and Ellis demonstrated that neurons can be generated from these Rett Syndrome iPS cells, the cell type affected in Rett Syndrome.
In conclusion, the EOS reporter will facilitate the generation of iPS and will be particularly useful for new labs going into this rapidly developing field. Furthermore, Rett Syndrome iPS cells that were also generated in this study will be invaluable for future drug screens that may be beneficial to those with Rett Syndrome.
Article:
Hotta, A. et al. Isolation of human iPS cells using EOS lentiviral vectors to select for pluripotency. Nature Methods 6, 370–376 (2009).
Related articles:
Breakthrough of 2008 – Reprogramming
A New Era for Disease Modeling and Drug Screening
Some of our experts
Stem Cell Origins
Cancer stem cells
Stem Cells and the Nervous System
i have a grandson with hurler disease and in north carolina duke u. hospital they did to my grandkid a transplant ,the kid only he would last less than 10 years ,and now he going to live all a full live, thank to the transplant and the doctor and the hospital,to me the stem cell transpant does work , thank you very much felix a proud granpa.
Embryonic stem cell research has taught us an incredible amount and we have much more to learn from them. Unfortunately, embryonics have overshadowed the advances of adult stem cell treatments.
There is a grim fairy tale going on in the US today derived from the love/hate relationship with embryonic stem cell TREATMENT research. You can view the 6 part series here: http://repairstemcell.wordpress.com/2009/03/30/a-grim-fairy-tale-americas-doomed-love-affair-with-embryonic-stem-cell-research-intro-the-romance-is-an-illusion/
The US is waking up to the fact that embryonic stem cells will produce no cures for 7-12 years if then and adult stem cells have been treating people around the world for up to 10 years successfully.
http://repairstemcell.wordpress.com/2009/04/03/oz-oprah-michael-j-fox-and-embryonic-stem-cell-research/
Both will continue, in addition to iPSC and epSPC research, and will do so accompanied by the hysteria, controversy, misinformation and confusion that they have been surrounded by for the past 10 years. My only hope is that the uneven focus on embryonic research does not continue to overshadow the successes of adult stem cells, thereby depriving more millions of Americans from receiving treatments that are available to them just a plane trip away.
In response to the comment by David Granovsky;
I would like to point out that the purpose of this forum is to provide information about all types of stem cell research, and to offer an honest appraisal of the current status of research and treatment technologies. Throughout the forum we have attempted to make clear that medical treatments using stem cells, adult or embryonic, are for the most part in the early stages of research, or in the rare occasion in early clinical trials.
I agree with David that research into all types of stem cells (embryonic, adult and induced pluripotent stem cells) has yielded a vast amount of knowledge about basic developmental biology, and offered the hope of treating debilitating disease in the future. However, the remaining content of David’s comment, in particular the information contained in the links, is full of misleading information.
It is difficult for me to determine the purpose of spreading this misinformation, which in some cases is encouraging patients to make decisions that might endanger their health, so thus I was considering deleting the comment outright. Instead of deleting the comment though I will encourage readers to link to the pages that David suggests as they are excellent examples of the type of pseudo-scientific web sites that exist that use a basic understanding of stem cell research to attempt to fool the reader into believing data or interpretations that are wholly unsupported by medical research.
The “six-part series” is a rather clumsy attempt to use widely known limitations of embryonic stem cell treatment (immune rejection, possible tumor formation) in combination with typical conspiracy theory (follow the money to the Big Pharma companies) to discredit embryonic research as a whole. Although the flaws in this argument are too numerous to fully recount and I think quite evident, I would like to point out a few things. Any treatment that does eventually come from an embryonic stem cell source will have to address the problems of immune rejection and uncontrolled cellular growth. However, the problem of controlling cellular growth is common to both embryonic and iPS cells and quite possibly adult human stem cells as well. The field of stem cell research is in fact centered around isolating stem cells and learning how they grow and divide in order to exert some control over these processes.
The author of the “six-part series” provides a link to his personal website (http://repairstemcells.org/Home.aspx). In an earlier post (December 15th, Principles of Responsible Translational Stem Cell Research) I detailed the disturbing trend of direct to patient marketing of stem cell therapies. I would encourage readers to read that post before linking to the repairstemcells.org site. The post discusses the issue of untested treatments being offered in foreign countries, often for great sums of money, with little or no scientific evidence to validate their claims. These websites prey upon the vulnerabilities of people that are desperate to relieve the suffering that can come from debilitating disease. This website is a very good example of this. The website is very professional and in some ways convincing in its “medical authority”. Two facts though should quickly alert the reader to evaluate the information extremely critically. First, the “research papers” that support the treatments being offered are not in fact research papers. They are not peer-reviewed clinical trials, but rather slick marketing tools produced by the vendor of the medical services. Secondly, the true purpose of these websites is evident when you attempt to get specific treatment information about a particular disease and are informed of the $10 000 - $24 000 or greater USD cost for these services.
I would encourage readers to critically evaluate any website or marketing tool that claims stem cell therapies, from any cellular source, are widely available for the treatment of many diseases. In truth, stem cell treatment is currently used clinically in a very limited set of circumstances, including the use of blood stem cells to repopulate the immune system after treatment of some forms of leukemia. Stem cell researchers are working hard, on all avenues of stem cell research (embryonic, iPS, and adult), and we remain optimistic that the knowledge we gain will be applied to human health issues in the future, but in the meantime talk to a trusted medical professional about treatment options that are properly tested and available today.
Lets let scientists decide which stem cells work best for which disease, not the religious right opponents of embryonic stem cell research.
I have had PD for 13 years and there are no successsful adult stem cell treatments for Parkinson’s. In fact, Dennis Turner’s PD returned 5 years ago after his supposed reprieve.
Lets not judge the research until it has been done, please!!!