Dr. Clem Persaud Responds:

In reference to a recent article in the journal Nature suggesting that earlier adult stem cell findings may have been misinterpreted, the writer wonders whether adult stem cells are a bust. The report of cell fusion in this article is a concern, not a catastrophe.

Arturo Alvarez-Buylla and his team of the University of California at San Francisco used a special technique to mark bone marrow stem cells injected into the blood of mice. They found that the marrow cells often, but not always, fused with existing liver, brain or heart muscle cells, and that the resulting hybrid cells did not divide to produce new cells. They concluded that earlier researchers wrongly inferred that new heart, liver or brain cells had been derived from pre-existing stem cells. The suggestion was made that embryonic stem cells, as opposed to adult stem cells, have the capacity to regenerate tissues of organs such as heart, liver and brain.

Some important considerations apply here. The research was done in mice- cell fusion involving adult stem cells and has not been reproduced in humans. The researchers used genetically altered marrow cells. It remains to be seen whether cell fusion is duplicated with peripheral blood and umbilical cord blood stem cells, genetically modified or not.  Interestingly, the authors concede that a few marrow cells may manage to change identities.

Embryonic stem cell work has been dogged with the finding of teratomas. The most recent report of this was an October 2003 report from the University of Dusseldorf: workers found that the use of mouse embryonic stem cells quickly resulted in tumors throughout the brain, a worrying implication for human patients.

In the clinical area, adult stem cells have shown great therapeutic potential. Last year, a study from the Imperial College School of Medicine in London combined bone marrow stem cell injection with kidney biopsies from men who had received kidneys from females. The kidneys showed Y-chromosome containing cells, leading to the conclusion that the bone marrow stem cells contributed to kidney regeneration as well as normal kidney cell turnover. Several papers at the November 2003 conference of the American Heart Association reported on clinical benefit following adult stem cell use. Two bear mention: after a transplant of his own blood stem cells, a 62-year-old Ottawa man had a 20% increase in function in a region of his heart that had been damaged by a heart attack. As well, an Arizona man, who had three heart attacks that left his heart weak and barely functioning, had his thigh muscle stem cells injected into his heart. It began beating efficiently, and he could now exercise. What is emerging internationally from these, albeit preliminary trials, is that transplanted adult stem cells appear to engraft successfully and function normally. Whether these cells stimulate old cells, or induce new cells, or do both, remains to be clarified.

The core issue still remains and it is this, in the face of the very promising results with an ethical alternative, and the associated reduced costs, our research funds should be chasing the potential of adult stem cells for humans to self-cure. There is no need for destruction of embryos to obtain stem cells when there is a viable alternative.  As someone has said, we can have the medical gain without the ethical pain.

Clement Persaud, Ph.D.
Biotechnology Professor (retired)
332-964 Heywood Ave.
Victoria, B.C. V8V 2Y5
[email protected]

Clement Persaud has spoken extensively on stem cells in Canada, and has appeared before the Standing Committee of Health of the House of Commons in relation to Bill C-13

See the original article “Stem Cells a bust?” that was in the National Post and on Reasononline
See more on the study
UCSF-led study raises doubts about marrow cell treatment for brain, heart—usr101403.php