Stem Cells: Embryonic vs. Non-Embryonic

The vagueness of the term “stem cell research” is one of the biggest problems in the ongoing stem cell debate. Writers, debaters, scientists, public figures and politicians should differentiate between “embryonic stem cell research” and “non-embryonic stem cell research” in order to keep the meanings clear.

What is the truth behind the claims of embryonic versus non-embryonic stem cells? The Aug. 7 issue of Time magazine attempted to answer this question, but it overlooked some key points in this politically charged debate.

First, researchers do not yet know which form of stem cells—embryonic or non-embryonic—will offer the most success in treating cancer, Parkinson’s, juvenile diabetes, Alzheimer’s, heart disease or spinal-cord injuries. Most likely, different types of cells and treatments will be needed for each condition. Well-documented research has revealed that there may be benefits of one form of stem cell over the other.

For instance it has been clearly demonstrated that non-embryonic stem cells (non-ESCs)—which include umbilical-cord cells, placental derived cells, as well as adult stem cells found in places such as blood, bone marrow, skin and breast—do not cause cancer in humans. Also, if non-ESCs are obtained from the patient or from a family member donor with a matching tissue type, the risk of immune rejection of the non-ESCs can be virtually eliminated.

By contrast, research has shown that embryonic stem cells (ESCs), which are derived from embryos that are destroyed in the process, have great potential to produce cancer in humans. Also, with ESCs it is necessary to employ techniques to avoid immune rejection of ESCs. One technique, called somatic cell nuclear transfer, is being attempted worldwide to produce customized ESCs. As Time pointed out in a related article in the Aug. 7 issue, somatic cell nuclear transfer is a “term researchers use to avoid the more incendiary word cloning, even though it is the same technology that created Dolly the sheep.” For this the embryo used as the source of ESCs is created in the lab by removing the nucleus from a patient’s normal somatic cell (for example, a skin cell) and using it (or the whole skin cell) to replace the nucleus that has been taken from a donated human egg. The egg which now has the nucleus from the patient is then allowed to grow in the lab until it becomes an embryo (at this point capable of becoming a human clone). This embryo is then destroyed to obtain the customized ESCs which are grown up in large numbers for therapeutic treatment for the patient. Theoretically, through this technique, these customized ESCs would not be rejected by the patient’s immune system.

Since the public’s knowledge of stem cell research may be limited, the public speaker or writer should consider educating the audience about the basics of stem cell research. Educating the audience is important because some people or organizations prey on the audience’s ignorance by failing to address essential facts. The Time article is a perfect example. When it discussed alternative uses for frozen embryos leftover from in vitro fertilization (IVF), it totally ignored the fact that many of these “snowflake babies” have been adopted, implanted into foster mothers who later have given birth to healthy human beings. Instead, Time emphasized that the leftovers “would otherwise be thrown away,” “otherwise be wasted,” or because “they come from infertile couples may mean they are not typical, and the process of freezing and thawing is hard on delicate cells.”

Another example was Time’s statement that, “Stem cells have shown a dismaying talent for turning into tumors.” This implies that all stem cells tend to produce tumors, but it should be made clear that only ESC have this problem. Throughout the article it is clear that for the sake of knowledge alone, we should be willing to destroy human embryos. This is defended even though the Time article cites a study indicating “at best only a couple hundred cell (useful) lines might be derived from (400,000) leftover IVF embryos.” The article also points out that a limited human egg supply will greatly restrict the utility of somatic cell nuclear transfer approaches “even if the technique for cloning embryos could be perfected.”

To date, non-ESC have shown much more utility in the clinic than untested ESC, something only mentioned later in the Time article and under the heading, “The Promise and Pitfalls of Adult Cells.” The research is certainly not complete, yet the dogmatic statement is made: “While not as flexible as embryonic cells, cord and placental cells have proved more valuable than scientists initially hoped.” No one knows yet whether non-ESC will be more useful or elastic than ESC. Time misleads the reader, though, by implying that research of non-ESC is not very useful and by stating, without any examples, that, “Many of these claims were overblown.”

In stem cell research discussions, it is only wise to be both specific and thorough while acknowledging the inherent worth of biological resources that can give rise to new life, whether cellular or whole human beings. We don’t want to look back in a few decades and realize we missed some great opportunities to treat people with our current capabilities and to build on this knowledge without putting too much of our resources and hopes in unproven technology. The expansion of proven technology may also help in our quest to keep scientific undertakings from outdistancing our ability to appropriately address ethical issues.

Durwood B. Ray

Durwood B. Ray

Dr. Durwood B. Ray is a fellow for medical ethics at The Center for Vision & Values as well as a professor of biology at the College.

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