For the first time, stem cell scientists have derived stem cells from cloned human embryos that were made from adult cells. This brings them closer to developing patient-specific lines of cells that can be used to treat a whole host of human maladies, but at a cost. This research was described in the April 17th online edition of the journal Cell Stem Cell.
In May of last year, Shoukhrat Mitalipov from the Oregon Health and Science University, reported the derivation of human embryonic stem cells from cloned human embryos. However, these cloned were made using cells that came from infants. Miltalipov worked out a new protocol for cloning human embryos by using nonhuman primate embryos, in particular those from a Rhesus monkey.
In this study, the donor cells came from two men, a 35-year-old and a 75-year-old. By using the protocol developed by Mitalipov and his group, Robert Lanza, Young Gie Chung, and Dong Ryul Lee and their colleagues made personalized embryonic stem cells from these two men.
Stem cell biologist Paul Knoepfler, an associate professor at the University of California at Davis who runs the widely read Stem Cell Blog, called the new research “exciting, important, and technically convincing.” He continued: “In theory you could use those stem cells to produce almost any kind of cell and give it back to a person as a therapy.”
In their paper, Young Gie Chung from the Research Institute for Stem Cell Research for CHA Health Systems in Los Angeles, Robert Lanza from Advanced Cell Technology in Marlborough, Mass., and their co-authors pointed out the potential promise of this technology for new regenerative therapies. However, their work is also an important discovery for human cloning, since it shows that age-associated changes are not necessarily an impediment to SCNT-based nuclear reprogramming of human cells.
Even though it was the intent of Chung and others to gestate these cloned embryos to form cloned children, this work could be the first step toward creating a baby with the same genetic makeup as a donor. Thus, this technology presents a so-called “dual-use dilemma.”
Marcy Darnovsky, executive director of the Berkeley, Calif.-based Center for Genetics and Society, explained that many technologies developed for good can be used in ways that the inventor may not have intended and may not like.
“This and every technical advance in cloning human tissue raises the possibility that somebody will use it to clone a human being, and that is a prospect everyone is against,” Darnovsky said.
This paper represents a collaboration between members of academic laboratories and industry. Funding for this work came from a private medical foundation and South Korea’s Ministry of Science.
Technically, the somatic-cell nuclear transfer protocols used in paper are still somewhat inefficient. Chung’s team had to attempt 39 times to produce only two blastocyst-stage embryos. Their first attempts were complete failures, but when they modified the Mitalipov protocol and activated the cloned embryos 2 hours after fusion rather than 30 minutes after fusion, the embryos grew successfully.
“We have reaffirmed that it is possible to generate patient-specific stem cells using [this] technology,” Chung said.
Shoukhrat Mitalipov, director of the Center for Embryonic Cell and Gene Therapy at Oregon Health & Science University, who developed the method that Chung’s group built upon, said that this work involves eggs that have not been fertilized.
“There will always be opposition to embryonic research, but the potential benefits are huge,” Mitalipov said.
Yes, there will be opposition to destructive research on embryos because they are the youngest among us. No they do not have the right to vote, drive a car, or buy a hunting license, but they have the right to not be harmed. To deny them that right because they cannot presently exercise particular capacities assumes that the embryo undergoes essential changes as it develops. But human embryos develop into the kinds of entities they become because of their intrinsic human nature that drives them to do so. Yes development is a progressive program that causes the embryo to acquire new structures and capabilities that it previously did not have, but what kind of entity can develop into a human adult that is not itself human? It takes a human embryo to make a human fetus, which makes a human new-born baby, which makes a human toddler, and do on. This continuum or development and change occurs throughout or lives and this continuum begins at the end of fertilization.
Cloned embryos begin this continuum at the completion of somatic cell nuclear transfer (SCNT). SCNT works as a stand-in for fertilization, but the result is still the same – a human embryo. It also should have the right not to be harmed, but instead she is being produced solely for the purpose of being dismembered. Is this the way we should treat the smallest and most defenseless among us? surely not. All this talk about, “well we did not form a fully human being” is a crock. Yes you did. You formed a fully formed human embryo. We were all human embryos at one time and these embryos developed into you and me. We were inarticulate and incapable at the time, but we gained those capacities over time. Again, how can something that gives rise to a human child not be human? The embryo is a human being, but it is a very young human being. Youth should not disqualify it from being able to live.
Seventeen years ago, when Ian Wilmut from the Roslin Institute in Edinburgh, Scotland announced news about the birth of the first sheep cloned from somatic cells named Dolly, several legislators called for a ban on human cloning. Several countries took measures to limit or outlaw such work, but in the United States. The cloning issue was obfuscated by dividing it into “reproductive cloning” for the purposes of making cloned children, and “therapeutic cloning” for the development of new therapies. Unfortunately, this dichotomy is slightly disingenuous since the techniques for both of these procedures are exactly the same except that reproductive cloning uses a surrogate mother to gestate the cloned embryo and bring her to term. Both of these procedures produce human embryos, but one uses them to make a baby and the other destroys them before they can do so.
President George W. Bush tried to split the difference by restricting federal funding for stem cell research that harms to a human embryo. This led to talk of Bush’s “embryonic stem cell ban,” which was inaccurate and was used unfairly used to paint Bush as an idiot. However, some 15 states have laws addressing human cloning, and about half of them ban both reproductive and therapeutic cloning.
Embryonic stem cell research has typically used embryos that are left over from the fertility industry. However, some religious groups such as the U.S. Conference of Catholic Bishops and others as well objected to this, since it destroys a very young human being.
However, about seven years ago, Shinya Yamanaka and his colleagues discovered a way to make induced pluripotent stem cells from mature adult cells. Genetic engineering techniques could convert ordinary cells into pluripotent stem cells without the need for human eggs. While this technique did not present the same ethical issues, some induced pluripotent stem cells lines contain significant genetic abnormalities and there is still debate over how safe these cells are for clinical use.
The research conducted by Mitalipov and Chung provides a second way of producing pluripotent cells through laboratory techniques that is, in my view, far less ethical and will almost certainly also have unintended consequences as well.