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ISIS Report

Hushing Up Adult Stem Cells

The science and technology of adult stem cells are running streets ahead of embryonic stem cells. But are the scientific establishment and the mainstream press hushing that up? Dr. Mae-Wan Ho and Prof. Joe Cummins review recent advances that make embryonic stem cells research unethical and unnecessary. Adult stem cells isolated from different tissues are developmentally as flexible as embryonic stem cells. Adult stem cells have been used successfully to repair damaged heart, and to treat a variety of disorders from auto-immune disease to cancer. Furthermore, they can be multiplied for many generations in the laboratory, and established cell lines obtained.


The British science journal, Nature, did a series of 'insight' articles on stem cells last November. Senior editor Natalie DeWitt refers to the excitement fuelled by "the controversial evidence that adult stem cells have a much higher degree of developmental potential than was previously imagined".

Almost none of the articles address adult stem cells directly, and where they do, the reader is given the impression that adult stem cells are simply not as good as embryonic stem cells. In the final article on 'ethical and social considerations', author Anne McLaren deplores attempts to "hype adult stem cells at the expense of ES cells". And while admitting that ES cells from somatic cell nuclear transfer, SCNT (involved in 'therapeutic human cloning') "may never prove economic for routine clinical treatment", "they could nonetheless make an immensely valuable contribution to medical research".

McLaren mentioned "a point of view" that SCNT presents no ethical problems, "because the entity to which it gives rise is not an embryo as defined as the product of fusion between sperm and egg, but an artefact, possessing no moral significance". The process did result in Dolly the sheep, but, "Is Dolly perhaps not a sheep, but merely an ovine cyborg?" She asked. So, by a clever escape clause, the bio-ethicist made the moral problem disappear in front of our very eyes.

By the same token, we should not object to reproductive human cloning, for such cloned humans are merely 'cyborgs'. Nor should we object to making cyborgs that serve real humans in any way we please. (Although it would be problematic to define who the real humans are.) Clearly that could not have been her intention. Her intention was to support embryonic stem cell research.

"Let a thousand stem cell lines bloom" she urged, "but let them bloom in full view of all, so that they can be subject to scientific and ethical review, freely available for research and one day, perhaps, for treating diseases." She has thus pre-empted public opposition to isolating embryonic stem cells from human embryos created by SCNT, and to research done on those cells.

Ironically, the company acknowledged for financial support of the series had a full page advertisement at the beginning of the series, where it describes itself as a company that "develops off-the-shelf cellular products based on the human mesenchymal stem cell (hMSC)". MSC is the best-characterised stem cell to-date, adult or embryonic. Contrary to the claims of the Nature 'insight', the scientific establishment has been hyping embryonic stem cells at the expense of adult stem cells, and has already been caught doing so.

An article published in Science earlier last year showed that mice cloned from embryonic stem cells by nuclear transfer suffered many genetic defects due to the genetic instability of the embryonic stem cells. The Washington Post reported that a key phrase referring to the genetic instability of the embryonic stem cells that might "limit their use in clinical application", was removed days before the paper appeared in print.

The Statistical Assessment Service (STATS), a non-partisan group dedicated to truth telling in political debates that involve science, found that the mainstream media had given great prominence to the potential of embryonic stem cells while under-reporting or completely ignoring research breakthroughs involving adult stem cells or alternate sources.

The US National Bioethics Advisory Commission (NBAC) recommended to Clinton to support embryonic stem cell research, but stipulated that this is "justifiable only if no less morally problematic alternatives are available for advancing the research."

It is now clear that such morally less problematic alternatives do exist, in readily available sources of adult stem cells, especially from patients requiring the treatment. We were among those who pointed this out a year ago ("The Unnecessary evil of 'therapeutic' human cloning" ISIS News 7/8, February 2001www.i-sis.org.uk), and numerous subsequent advances have proved our case.

The main protagonists of embryonic stem cell research are the scientists working with those cells. A typical case made on why embryonic stem cell research should be supported goes like this.

a.. Embryonic stem cells are 'pluripotent', ie, they can make every cell type of the body, while adult stem cells are 'multipotent' and can make many, but not all cell types. Consequently, adult stem cells may be immensely useful for treatment of some human disease, but unable to make certain cell types required for treatment of other, unspecified, diseases.

b.. Adult stem cells, unlike those derived from the embryo, cannot be expanded in culture without losing developmental potential.

c.. Finally, many of the claims of adult stem have not appeared as peer-reviewed publications. In fact, all those arguments have long been overtaken by events. There are many excellent peer-reviewed publications showing that adult stem cells may be just as developmentally flexible as embryonic stem cells, that these stem cells show much greater promise in repairing damaged tissues and treatment of other diseases, and that they can give rise to established cell lines, if needed.

Furthermore, unlike stem cells isolated from the embryo, they do not carry the same risks of cancer or uncontrollable growth after transplant, and they can be isolated from patients requiring treatment, thus avoiding all problems of immune rejection and the need for immune suppressive drugs that carry their own risks.

The developmental potential of adult stem cells has been documented in numerous publications. For example, bone marrow cells enriched for hematopoietic (blood) stem cells (HSC) can differentiate into mature liver cells in the liver of rodents and humans. Mouse bone marrow cells can generate skeletal muscle cells in the body, and skeletal muscle cells can give bone marrow cells. Bone marrow could be reconstituted from cultured brain, and glial and neurons cells were obtained from bone marrow.

More recently, a 'pluripotent neural stem cell' was isolated from adult mouse brain, where it constitutes 1 in 300 cells of the brain. It not only gave rise to all types of cells in the brain, but when cultured with a muscle cell line, developed into muscle cells. These neural stem cells can be grown indefinitely in culture.

Researchers have also provided definitive proof that one single adult stem cell from bone marrow can reconstitute the bone marrow of a mouse destroyed by irradiation, as well as develop into practically all the tissues of the body. Established cell lines have been obtained from one type of bone marrow stem cells.

Another source of readily available adult stem cells turns out to be skin. Skin stem cells can make neurons, glia, smooth muscle and fat cells. Again, cell lines have been established that kept their pluripotency for at least one year.

Embryonic stem cells are promoted on ground that they are developmentally more flexible than adult stem cells. But too much flexibility may not be desirable. Transplant of embryonic cells into the brains of Parkinson's patients turned into an irredeemable nightmare because the cells grew uncontrollably. Embryonic stem cells also show genetic instability and carry considerable risks of cancer (see ISIS News 11/12 www.i-sis.org.uk). When injected under the skin of certain mice, they grow into teratomas, tumours consisting of a jumble of tissue types, from gut to skin to teeth; and the same happens when injected into the brain.

A new paper in PNAS reports how mouse embryonic stem cells injected into the brain of adult rats developed into neurons. The rats had previously had their dopamine-producing neurons damaged and showed a characteristic tendency to move in circles toward the damaged side of the brain, mimicking Parkinson's disease.

Actually, six of the 25 rats injected showed no evidence that the mouse embryonic stem cells had survived. Five died with teratomas in the brain. The 14 remaining had mouse stem-cell derived neurons in their brain, but showed only a modest 40% behavioural improvement over untreated controls.

Injected adult stem cells are different, they grow into other tissues only when appropriate growth factors are applied, or when given other external cues. Indeed, adult stem cells already have a record of relatively safe, effective therapy, especially when cells from the patients themselves are used.

We reported on the use of the patient's own bone marrow cells to mend damaged heart in ISIS News 11/12 (www.i-sis.org.uk). The patient's bone marrow stem cells have also been successfully used to treat juvenile chronic arthritis, severe systemic lupus erythematosus, an auto-immune disorder with multiple organ dysfunction, and Crohn's disease affecting the bowels.

Bone marrow transplant from the daughter provided 'killer cells' that were tolerated by her mother, thereby ridding the mother of an otherwise untreatable cancer.

It is clear that human embryonic stem cell research is both unethical and unnecessary, and should not be supported, least of all with public finance. An indication of the promise of adult stem cells relative to embryonic stem cells is that private finance for the former is outstripping the latter two to one.

Our tax money should not be spent to indulge the whims of scientists who cannot see beyond their own self-centred narrow interest, and who are totally insensitive to the moral concerns of the rest of humanity.

 


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