by Dr. David Fleischacker
Only adult stem cells work in adult tissues. Embryonic stem cells work in embryos, not mature organisms.
The Term “Stem Cell”
Unfortunately, the technical language that develops within a discipline does not always suggest what it should, especially when it is used in the general public. I think this is the case with the use of “stem cell” for both Embryonic and Adult stem cells. The term itself is not a problem, since stem cell suggests an originating cell. To that degree, the language is fine. Both embryonic stem cells and adult stem cells are origins of more mature types. However, in people’s minds, the use of the term suggests a greater relationship between the two types of stem cells than actually exists.
The relationship I believe that has been created for the political arena is that embryonic stem cells could be directly inserted into the same locations as any adult stem cell, and they will do the same thing as those adult stem cells. It is like a one stop solution, since embryonic stem cells are sold as cells which can become any type of cell in the body. However, this one stop solution simply is not true. Embryonic stem cells are designed to work properly at the beginning stages of the organism, not at its mature stage. Conversely, the adult stem cells work properly at the mature stage, not at the beginning stages. Swapping adult stem cells with embryonic stem cells does not work therapeutically for all kinds of genetic, biochemical, and organic reasons.
The Developmental Relationship between Embryonic Stem Cells and Adult Stem Cells
There is of course a relationship between embryonic and adult stem cells, one that is developmental. Stems cells of any type have a relation of finality to the mature types into which they emerge. In Embryonic stem cells, one is speaking of cells that exist early on in the life of the organism which then unfold into all of the various cells types of a mature organism, which includes adult stem cells. As this unfolding takes place, a variety of genetic, biochemical, and organic changes take place (one might be surprised that genetic changes take place. This refers to the actual packaging of the DNA molecules which causes shifts of the actual genes that can be transcribed). Adult stem cells in contrast maintain and heal the various organic systems in the body, and thus have significant differences in the genetic and biochemical schemes that are operative. In short, there are a variety of developmental stages between embryonic and adult stem cells. These stages effect a series of developmental shifts with all the accompanying changes that take place in the genetics and biochemistry of the cells.
Adult Stem Cell Therapy. There is NO Embryonic Stem Cell Therapy.
Thus, theoretically, embryonic stem cells can lead to the creation of adult stem cells, and then potential therapies from diseases that are treatable by healthy adult stem cells. But this is the key, one cannot simply use an embryonic stem cell directly in an adult without problems. ONLY adult stem cells can be used in adult tissues (and ones that would not be rejected as “foreign” cells by the immune system).
In embryonic stem cell therapies used in animal experiments, many of the troubles found are related to control of cell division and maturation. In these experiments on animals, embryonic stems cells sometimes function in the right way in adult tissues, at least in part, however they lack the rather nuanced schemes for equilibrium. What happens when equilibrium schemes fail to work properly? One of the results in these animal experiments is cancer (cancer is uncontrolled cell growth). Unfortunately, when we read of the healing successes that occur in these animal experiments that result from embryonic stem cells, the conclusion is not added in, namely that the animal then died of cancer.
The medical point thus is simple to make. For embryonic stem cells to be of medical use, they have to be “developed” into adult stem cells so that they operate properly within adult tissue systems. There is no magic to this. However, there are no such therapies derived from embryonic research yet, because little is still known about how embryonic stems cells develop into adult stem cells, and even less about creating treatments from the knowledge of these stages. In contrast, adult stems cells are already adult stem cells. They can be used in adult tissues, because that is where they are derived (as long as the standard problems of rejection by the immune system are resolved). Thus, there is no magical reason why over 100 types of human stem cell therapies exist in this world which are derived from adult stem cell research, NOT embryonic stem cell research. In fact, not a single human therapy has been developed from embryonic stem cell research. There is no magical reason to this either.
So, if you have some hope that embryonic stem cell research will prove more medically valuable, it simply is not true. Only adult stem cells work properly in adult tissues. It is a simple fact already known in the stem cell community. And it is much easier to develop therapies from adult stem cells than from embryonic, and thus, the likelihood of eventually creating embryonic stem cell therapies is minimal.
And of course, this simply addresses the direct pragmatic outcomes of stem cell research. It does not address the ethics of the means, especially when the means on the one side is the destruction of an embryonic child. That, is a topic for another blog. People might be willing to kill others for medical benefits, others might be willing to kill for scientific benefits. But killing human life for scientific or medical benefit necessarily proceeds from a hardened heart.