[[Comments: While it would be great of course to find ethical alternatives to the use of human embryonic stem cells (for therapies and for basic research), the article copied below indicates once again that scientifically iPS cells would not constitute that final "ethical alternative". There have also been several similar research studies over the last few years which have indicated similar scientific problems with iPS cells. But there are also a number of ethical concerns that continue to plague iPS stem cell research. For example:
(1) Referring to iPS stem cells as "adult" stem cells is very misleading. Real "adult" stem cells obtained from adult human tissues and organs are initially "multipotent", and then are re-programmed to become even more differentiated cells, whereas iPS cells are obtained from adult cells that are de-programmed back to "pluripotency" to become far less differentiated cells. That is, real "adult" stem cells are never manipulated to become "pluripotent", whereas iPS stem cells are. The ethical concern is that, especially with little or no control over this de-programming or de-methylations process (as demonstrated in the studies addressed by the article below), "totipotent" cells could result instead of "pluripotent" cells. Since "totipotent" cells are by definition capable of being reverted to new single cell human embryos by means of the natural biological process of "regulation" or "de-methylation", if any totipotent cells do result from these iPS techniques they could indeed revert back to new single-cell human embryos which would then be destroyed. Please, this is not to say that all totipotent cells are embryos (as I have been misquoted as saying). It is to say that the real possibility exists that such totipotent cells might revert to new single-cell embryos because they possess the natural biological process of "regulation" or "de-methylation". Of interest is that: a) none of these experiments test directly for "totipotency", only for odd tumor-producing properties of "pluripotency" -- so they don't know -- empirically -- if any human embryos have been "accidentally" produced during the iPS process; and b) their definitions of "pluripotency" and of "totipotency" are scientifically incorrect. For more details and scientific references on these concerns, see:
(2) iPS research, as well as most other similar types of research, require the use of "biological materials" that are derived originally from human embryos and human fetuses and then used throughout these experiments . This has been acknowledged by these researchers themselves. That is, even aside from the very real possibility that real living human embryos might be "accidentally" reproduced during the iPS process, the fact remains that bits and pieces of human embryos and fetuses are used throughout these experiments (e.g., in the media used, the feeder cells used, the "controls" in assays and machines used, etc.). Therefore, such research could hardly claim that it was "free" of the unethical destruction of any human embryos and fetuses. This concern about the use of human embryonic and fetal "biological materials" in iPS stem cell research holds for related research as well, such as somatic cell nuclear transfer (SCNT), ANT, OAR, etc.
(3) It should also be pointed out in fairness that the quote attributed to Debi Vinnedge (Executive Director of Children of God For Life) as stated in the article below is also not completely accurate. (On the other hand, these scientific "details" are often difficult for those with little scientific background, like reporters and most other people, to comprehend). Debi Vinnedge is quoted as saying that "the study wasn't particularly helpful in resolving moral issues surrounding stem-cell research because both types of cells start with the aborted fetus." This interpretation of what was said to the reporter could be misleading, because, as Ms Vinnedge knows well, neither iPS research nor human embryo research literally begin with an "aborted fetus". Rather, the point Ms Vinnedge was trying to make, and as she so stated to the reporter, was that "both involve the destruction of innocent human beings." Ms Vinnedge explained to the reporter that whether or not embryos were continuously destroyed in a specific research protocol was not the issue; one had to destroy embryos and fetuses in order to produce the embryonic cell lines used that specific research protocol to begin with. She thus explained that "From a moral perspective, there's no difference between embryonic and reprogrammed adult stem cell research because scientists used embryonic stem cells and/or aborted fetal cell lines in order to accomplish the reprogramming," Similarly, she also pointed out to the reporter that the Bush decision on using only those existing embryonic stem cells for federal funding was still morally wrong simply because embryos had to have been destroyed somewhere along the line -- it's just that tax dollars were not used for the actual initial destruction. [Personal communication] For an in-depth analysis of both the scientific and ethical concerns surrounding iPS research, see Irving, "Ethical and Scientific Concerns About Induced Pluripotent Stem Cell Research -- Yamanaka and Thomson" (June 1, 2008), at: http://www.lifeissues.net/writers/irv/irv_127concerns.html. -- DNI]]
http://www.washingtontimes.com/news/2010/jul/19/adult-stem-cells-said-to-forget-retooling/
WashingtonTimes.com
Monday, July 19, 2010
Title: Adult stem cells said to 'forget' retooling
Embryonic alternative suffers setback
By Valerie Richardson and Kathryn Watson
Reprogrammed adult stem cells may not be as useful an alternative to controversial embryonic stem-cell research as had been hoped, researchers found in two articles published Monday.
Researchers at Children's Hospital Boston and Johns Hopkins University published an article online in the prestigious journal Nature finding that such adult stem cells remain fundamentally different from embryonic stem cells and are no better at curing diseases in mice.
Many in the medical community and among pro-lifers have hoped harvesting embryonic cells, which destroys the days-old human embryos and has provoked intense ethical and moral criticism, could be avoided if scientists could manipulate adult cells to act as if they were embryonic stem cells.
Called "induced pluripotent stem cells" (or iPS), the altered adult cells "forget" they were once cells naturally "programmed" to become liver cells, lung cells, skin cells, etc. This would make them, theoretically, as useful as embryonic cells for a variety of miracle cures, especially for degenerative diseases such as Alzheimer's.
It turns out, the studies say, that they don't forget.
"Our data indicate that nuclear transfer [from embryonic stem cells] is more effective at establishing the ground state of pluripotency than factor-based reprogramming [of adult stem cells], which can leave an epigenetic memory of the tissue of origin that may influence efforts at directed differentiation for applications in disease modelling or treatment," the article's findings stated.
A second, separate group of scientists led by Konrad Hochedlinger, a stem-cell biologist at Massachusetts General Hospital Center for Regenerative Medicine, published similar findings Monday in Nature Biotechnology. That group said the adult cells obtained from mice exhibited distinct patterns that could not be erased.
Kitai Kim, a postdoctoral fellow and one of the leading researchers on the project published in Nature, explained that older cells are more set in their ways and difficult to reprogram. His group worked with mice, reprogramming different kinds of cells with varying results.
The needed DNA change "was incompletely reset in [reprogrammed adult] cells compared to nuclear-transfer stem cells," said co-senior author Andrew Feinberg. "This paper opens our eyes to the restricted lineage of iPS cells. ... The lineage restriction by tissue of origin is both a blessing and a curse. You might want lineage restriction in some cases, but you may also have to do more work to make the iPS cells more totally pluripotent."
Those who oppose using embryos for stem-cell research have long argued in favor of replacing them with adult stem cells. Critics have argued that embryonic stem cells are scientifically superior to adult stem cells. And the researchers said the findings demonstrate that the scientific focus needs to be on embryonic stem-cell research.
Arthur Caplan, director of the Center for Bioethics at the University of Pennsylvania, said the results of the study weren't surprising from a scientific perspective, but could still have enormous implications for future research.
"A giant balloon of enthusiasm just got the air let out of it," said Mr. Caplan.
"What this shows is that ideology and values are no substitute for science," he said. "The science on this is still early, and the values and moral beliefs are going to have to wait until the science has told us what's possible."
Debi Vinnedge, executive director of the Children of God for Life, which opposes using embryonic stem-cell research, said the study wasn't particularly helpful in resolving moral issues surrounding stem-cell research because both types of cells start with the aborted fetus.
"From a moral perspective, there's no difference between embryonic and reprogrammed adult stem cells because scientists used embryonic stem cells and/or aborted fetal cell lines in order to accomplish the reprogramming," Ms. Vinnedge said.
The research did show, however, that while reprogrammed stem cells may not be as versatile as embryonic ones, they can still be quite useful.
Thousands of patients around the world have been treated with adult stem cells, but no humans as of yet have been given cells derived from embryos in an approved trial.
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