The "holy grail" of regenerative medicine would be stem cells that are pluripotent (able to become most or all of the 200 cell types in the body) that are also a genetic match to a patient. This would mean that a patient could be treated with cells that are flexible enough to become whatever cell type is needed but also would not require that the patient take drugs to prevent rejection like with other transplants.
As of now, there are two ways that scientist are looking to achieve this. Therapeutic cloning is the first. Therapeutic cloning would create a cloned embryo that would be a "genetic match" to the patient and then that cloned embryo would be destroyed for the embryonic stem cells inside. Unfortunately, this approach has all kinds of problems. First and foremost, it would create and destroy human life which is never justified even if the outcome is a proposed good. Secondly, this approach would require a multitude of human eggs which would put young women at risk of exploitation. Egg donation is an involved process that in some cases can cause infertility and, in rare cases, death. Thirdly, the cloned embryo would not truly be a genetic match to the patient because there would be DNA leftover from the woman who donated the egg. Finally, this approach opens the door to reproductive cloning, or cloning to produce children, which nearly everyone finds repugnant.
Induced pluripotent stem cells (iPS cells) are considered the alternative to cloning for embryonic-like stem cells. In this approach, scientist take a cell from the patient and "reprogram" it back to an embryonic-like state. These cells would be a genetic match to the patient and they appear to behave just like their embryonic brothers. No eggs, no embryos, no cloning, no creation or destruction of human life. Genetically matched pluripotent stem cells without all of the ethical issues.
In the past, this approach had one real problem. To "reprogram" the cell, researchers had to insert four genes into the DNA of the cell with viruses. Some of these viruses have been known to cause cancer and inserting and leaving genes in the genetic material of a cell that would be used for therapeutic reasons is never a good idea.
This week researchers have announced that they have overcome this problem. They used a system that inserts the four genes needed to reprogram the cell and then removes them. From the Washington Post:
In the new work, Nagy and his colleagues in Toronto and at the University of Edinburgh in Scotland instead used a sequence of DNA known as a transposon, which can insert itself into the genetic machinery of a cell. In this case, the researchers used a transposon called "piggyBac" to carry four genes that can transform mouse and human embryonic skin cells into iPS cells. After the conversion took place, the researchers removed the added DNA from the transformed cells using a specific enzyme.
"PiggyBac carries the four genes into the cells and reprograms the cells into stem cells. After they have reprogrammed the cells, they are no longer required, and in fact they are dangerous," Nagy said. "After they do their job they can be removed seamlessly, with no trace left behind. The ability for seamless removal opens up a huge possibility."
Scientists used embryonic skin cells for this study, but are confident that it will work in adult cells as well. This breakthrough naturally begs the question: Can we stop destroying human embryos for their biological material now?
Some scientists say that research into both iPS and embryonic stem cells is needed to see which will be better for treatment. But I say, why create and/or destroy human life when there are promising alternatives that do not? Why take more of the limited taxpayer dollars and divert them from iPS research to research on embryos, cloned or otherwise, when the ethics is such a huge issue?:
"Stem cell research that requires destroying embryos is going the way of the Model T," Richard M. Doerflinger of the U.S. Conference of Catholic Bishops said. "No administration that values science and medical progress over politics will want to divert funds now toward that increasingly obsolete and needlessly divisive approach."
I truly believe that the research into iPS cells would not be advancing at such an accelerated rate if there was not such a huge outcry all over the world against using human embryos for research. This moral outrage was called all kinds of ugly names. Those of us who expressed it were labeled religious fanatics with no compassion for the sick. I believe, in the end, it will be this unpopular moral argument against using human embryos for research that will be tipping point toward a better and more ethically sound treatment.