Ethical Embryonic Stem Cell Research?
Ethical New Stem Cell Approach?
Excerpted from "New Stem Cell Approach Reported." By Malcolm Ritter. Associated Press.
September 22, 2006--Scientists say they have created a stem cell line from a human embryo that had stopped developing naturally, and so was considered dead. Using such embryos might ease ethical concerns about creating such cells, they suggested. One expert said the technique makes harvesting stem cells no more ethically troublesome than organ donation. But others said it still carries scientific and ethical problems.
Scientists want to use human embryonic stem cells to study diseases and create transplant tissue for treating illnesses such as diabetes and Parkinson's disease. Such cells are taken from human embryos that are a few days old, and the harvesting process destroys the embryo. That raises ethical objections. The new work, published online Thursday by the journal Stem Cells, comes from Miodrag Stojkovic of the Prince Felipe Research Center in Valencia, Spain, with colleagues there and in England. They studied embryos donated by an in vitro fertilization clinic with consent of the patients. Part of the work focused on 132 "arrested" embryos, those that had stopped dividing for 24 or 48 hours after reaching various stages of development.
Thirteen of these embryos had developed more than the others, reaching 16 to 24 cells before cell division stopped. Scientists were able to create a stem cell line from just one of these embryos. These stem cells performed normally on a series of tests, Stojkovic said in a telephone interview. He said he did not know whether the result indicated a solution to ethical concerns about embryonic stem cells. The point of the research was to show that such embryos provide an additional source of the cells beyond healthy embryos, rather than to set up any kind of a competition, he said. Both sources should be used, he said. Full Article
CMDA Executive Director Dave Stevens, MD comments: "It would be great to find an ethical source of embryonic stem cells to use to better understand human cell development, though using them for therapy is unlikely for many years. Has Dr. Stojkovic done that?
The big question is whether blastomeres at this stage of development are totipotent (capable of developing into a complete organism or differentiating into any of its cells or tissues) or pleuropotent (capable of differentiating into one of many cell types). Can they develop into a complete human being or are they too differentiated? If they are totipotent, sacrificing a blastomere is morally equivalent to sacrificing an entire embryo. In mice we know that blastomeres, put in the right environment, will multiply, organize and create trophoblastic cells.
The second question is what is the moral status of an arrested embryo? Are they equivalent to a brain dead organ donor? My personal opinion is that they probably are if their development arrest is irreversible and nothing was intentionally done to cause their further development to be halted.
The third question is a scientific one. Are these cells and the ESC line that could be made from them, normal? Is there some genetic or other flaw that has caused the arrested development that will contaminate the ESC line?
Dr. Stojkovic did not undertake his research to find an ethical source of ESC’s, but it would be wonderful, pending the right answers to these questions, if he has found it."
Labels: Biomedical Ethics