The scientific and ethical debate regarding the use of stem cells in medical research has been raging for over a decade. With President Obama reversing the previous administration’s limits on federal funding for embryonic stem cell research, this debate can only intensify in the months and years upcoming.
What Is a Stem Cell?
At the heart of this debate is something called a stem cell. Simply put, stem cells are the types of cells from which all the different tissues of the body are derived. To understand this, just picture what happens when a sperm fertilizes an egg. There is initially one cell; that cell divides into two cells; those two become four; and so on. From these first few cells, over 200 different tissue types in the body are made. These initial cells are called stem cells, and they have the ability to change into the various tissues required as the embryo develops. This process of stem cells turning into more specialized tissue is called differentiation.
As stem cells mature, they become more specialized. As a result of this process, the number of different tissues into which a stem cell can transform becomes limited. That is, after a certain point a stem cell may no longer be able to give rise to nerve cells or skin cells but may be able to produce blood cells or pancreatic cells. This loss of ability to differentiate is one of the key arguments in the debate over stem cell research.
Embryonic Stem Cells and Adult Stem Cells
The two primary types of stem cells involved in this field of research are embryonic stem cells and adult stem cells. Embryonic stem cells are derived from embryos (typically four to five days old). A ball of cells called a blastocyst is disrupted, and the embryonic cells are harvested. These cells grow rapidly and have the potential to transform into any cell type in the body.
Adult stem cells are found in virtually every tissue in the body. However, they are found in relatively small numbers in these tissues. Generally, they only make the cells specific to the area in which they are located. These cells grow less rapidly in laboratory culture than embryonic stem cells (but this is not the disadvantage it appears to be—embryonic stem cells can grow so rapidly that they can be difficult to control). Theoretically, adult stem cells have less potential to produce all the needed cell types required for adequate medical research.
Problems with Embryonic Stem Cells and Benefits of Adult Stem Cells
Proponents of embryonic stem cell research claim that these cells are superior to adult stem cells, and our research efforts should be concentrated in this arena. Are these claims of superiority valid?
First of all, in the last few years, researchers have succeeded in producing virtually every tissue type from adult stem cells. In fact, according to the National Institutes of Health, “A number of experiments have suggested that certain adult stem cell types are pluripotent.”1 So, it is apparent that the claim that embryonic stem cells can produce more tissue types is not true.
Also often overlooked is the problem of tissue rejection. When a patient gets an organ transplant there is always a concern the recipient’s body will reject the donated organ. The same concern exists in therapy with embryonic stem cells. These cells are, in fact, foreign to the recipient’s body and can cause rejection. This would not be the case with adult stem cell therapy, as the patient would be receiving his or her own cells back. These transformed cells would be recognized as “self” and should not induce rejection.
In some studies, embryonic stem cells have been found to produce tumors. This has not been a problem with adult stem cell therapy.
The claim of therapeutic benefit for embryonic stem cells is not borne out by the many years of research with adult stem cells. At present over 70 diseases have been treated with adult stem cell therapy. In fact, blood forming stem cells have been used in transplants for over 30 years.2 In contrast, the track record for the use of embryonic stem cells in clinical applications demonstrates no successes: “However, to date, no approved medical treatments have been derived from embryonic stem cell research.”3
Embryos Are Human Beings
The overriding objection to embryonic stem cell research is that in order to obtain these cells, a human life must be terminated. Embryonic stem cells are obtained by disrupting a blastocyst, which is what the embryo is called four to five days after fertilization. While there are many arguments claiming this is not immoral, one must ask the question, “Is it just to kill one person to save another?” Given the absence of success with embryonic stem cell research, perhaps the better question is, ”Is it just to kill one person in the hope of saving another?”
Life begins at conception (here defined as the moment the sperm and egg unite), and, thus, the embryo at day one is a precious human life. The origin of the stem cells we use for research is vitally important (my colleague, Dr. Georgia Purdom, has written an excellent article on the subject). It is curious that in our society some people are so concerned that we pursue this research to help the sick because it is the “humanitarian” thing to do, and yet they deny the humanity of those destroyed to do so.
I am certain that President Obama’s concern for the sick and dying is genuine. However, with this decision the defenseless unborn are put in harm’s way on only the faint promise of benefit. Research with adult stem cells is showing great potential. Would it not be better to use our present resources (as scarce as they are right now) on technology that has already shown such promise?