Stem Cell Debate Is History

The only stem cell that has NOT been associated with a cure of some disease or affliction is, ironically enough, the embryonic stem cell. We could not find in the literature a single case of any patient—not one—that has been cured of anything using embryonic stem cells. On the other hand, the number of case reports where adult stem cells reportedly cured patients is in the hundreds.

Probably the most famous of these is Osiris Therapeutics’ GVHD (graft-versus-host disease) patients. In the Phase II trial completed last year, the company reported that of the 32 patients enrolled in the trial, 94% responded after receiving two infusions of adult stem cells (Prochymal), and 74% of these respondents had total clinical resolution of the disease. In addition, those patients who experienced a complete response rate by day 28 had a statistically significant improvement in survival as compared to patients experiencing a partial or non-response.

Why, therefore, are the press and most of the general public still talking about embryonic stem cells?

D
Dr. Anthony Atalar. Anthony Atala, Director of Wake Forest's Institute of Regenerative Medicine and the leading researcher of using birth tissues to supply stem cells for therapeutic use, said, “When compared with embryonic stem cells, amniotic fluid stem cells (AFS) have two main advantages: First, no embryo needs to be harmed in harvesting the cells, sidestepping a major hot-button political issue, and [second] AFS cells will not form tumor cells, as the considerably more raw embryo-derived cells can.”

"They're not as early and they're not as wild, " he explains. "The cells are further along the line of development―and you don't see fetuses developing tumors—so these cells are much more controlled."

Embryonic stem cells are harvested from two sources: 1) Embryos – harvesting living embryos that are 5–7 days old. This method results in the death of the embryo. 2) Fetuses – stem cells are harvested from miscarriages or aborted babies.

Adult stem cells, on the other hand, seem to be popping up everywhere. The Journal of Translational Medicine (Jazedje T, Perin PM, Czeresnia CE, et al. Human fallopian tube: a new source of multipotent adult mesenchymal stem cells discarded in surgical procedures. J Transl Med. 2009;7:46 Epub) reported last week that Fallopian tubes removed from fertile women of child-bearing age during hysterectomies or other procedures are an amazingly rich source of stem cells or, more accurately stated, limited lineage progenitor cells.

These are not embryonic cells. Instead, these cells have already progressed down a particularly evolutionary pathway—specifically, the lineage that leads to muscles, bones, nerves, or blood vessels. These cells, for example, won’t evolve into eyes or brain or teeth.

Researchers from the University of Sao Paulo in Brazil found that human fallopian tubes are rich in mesenchymal stem cells. The team isolated and grew these cells in a laboratory and differentiated them into muscle, fat, cartilage, and bone cell lines.

"In addition to providing an additional potential source for regenerative medicine, these findings might contribute to reproductive science as a whole, " study leader Tatiana Jazedje, of the university's Human Genome Research Center, said in a news release from the journal's publisher.

Past studies have also shown success with isolating and differentiating mesenchymal stem cells harvested from umbilical cords, dental pulp and body fat.

Dr. Angela ChristianoThen we ran across Dr. Angela Christiano’s paper in Cell. Dr. Christiano is the Director of the Basic Science Research Group as well as the Richard and Mildred Rhodebeck Professor of Dermatology and Professor of Genetics at Columbia University. Her research has shown that two subpopulations of cells exist within the hair follicle, including stem cells.

These progenitor cells, Dr. Christiano showed, have significant plasticity and can differentiate into bone marrow, muscle, bone, fat, and neural cells. The neuronal differentiation of hair follicle stem cells, together with their ease of access as adult stem cells, prompted Dr. Christiano and her team to study the use of hair follicle stem cells for neurological and degenerative diseases.

Birth tissues, hair follicles, bone marrow, retina, intestines, teeth enamel, and fat. Where will it end?  In fact, we have even found articles that describe harvesting neural stem cells from areas of cadaver brains as part of standard allograft recovery processes.

The contrast with embryonic research is startling. So much so that any debate about the relative merits of adult versus embryonic stem cells is settled. Done. Stick a fork in it. Embryonic stem cell research is still looking for its first cure without, incidentally, triggering a tumor.

Source: Wikimedia Commons images,
author Mikael Haggstrom, Public Domain

Embryonic cells can be tumorigenic. This past February, an online article detailed the case of a 9-year-old boy suffering from ataxia-telangiectasia, a childhood disease that causes degeneration of parts of the brain. The condition has no cure. So the child’s parents went to the Soviet Union for embryonic stem cell injections. A benign brain tumor resulted. Surgeons in Israel removed the tumor, wrote the case up and published it in the February 2009 online version of Scientific American.

Adult stem cells, also known as limited lineage progenitor cells, have overwhelming advantages over embryonic stem cells including:

1. Plentiful supply
2. Thousands of relevant case histories
3. Rich clinical history with more than 100, 000 patients treated
4. Easy to harvest or purchase (allograft or autologous)
5. Non-tumorigenic
6. Ease of implantation

This year, we estimate, limited lineage progenitor cells whether in allograft form or autologous forms (bone marrow or adipose tissues) will be used in more than 20, 000 patients and generate more than $85 million in revenues. By the end of this year, four companies will be offering products with limited lineage progenitor cells. By the end of 2010, that number could double.