A Brief Update on Adult Stem Cells

Readers of The New York Times and other news outlets may have seen the May 17 announcement that Prochymal, an “adult” stem cell-related therapy to treat children with graft-versus-host disease, was approved in Canada by Health Canada (which is what they call their FDA up there). This treatment, which is made by a company called Osiris Therapeutics, is being tested for other medical conditions. Success does not appear to be uniform, which is to be expected. Most new medical treatments fail in at least some envisioned applications.
Graft-versus-host disease is a complication of transplantation—usually, as in this case, bone marrow transplant—in which immune-competent cells in the donated graft attack the tissues of the recipient. A little bit of this may be tolerable or even desirable, medically speaking, but too much is not pretty. The cells in Prochymal are so-called “mesenchymal” cells, derived from bone marrow. That is, they are in the marrow but are different from the cells, also in the marrow, that are destined to make mature blood cells. They are obtained from healthy adult bone marrow donors and are made into a treatment that can be prescribed “off the shelf,” so you don’t have to find new donors every time you want to use them. That is a neat technical feat.
Recall that somatic or “adult” stem cells are found in different tissues of the body and have different abilities to be transformed into some other kind of cell. They can’t make a whole individual. Readers of this blog will recognize them as the “good guys” of stem cell research and therapy.
This treatment is not yet approved in the U.S. I suppose it might be in the future. It seems to have followed a pretty standard scientific, ethical, and regulatory paradigm for the development of new drug and biologic treatments.
Most, but not all, adult stem cell treatment involves stem cells that specifically exist to form blood cells, for use as bone marrow transplants. These cells can come from a donor’s bone marrow, or they can be filtered out of the blood stream, where they circulate, or, increasingly, they come from umbilical cords. These historically have been used by medical centers as a procedure, but central banks are arising to procure, store, and provide them. Accordingly, the FDA is regulating them more and more as products like drugs.
There is ONE such adult stem cell product approved by the FDA—Hemacord, which consists of umbilical cord cells. There are late-stage trials seeking to establish that adult stem cells from bone marrow are useful in treating heart failure, for example, but to my knowledge final results are not yet available.
There are also a number of efforts to use people’s own adult stem cells for them—for example, in plastic surgery. FDA regulations require that this use be limited to cases where there is “minimal” manipulation of the cells, and the threshold for “minimal” is being fairly hotly disputed. If it is exceeded, FDA asserts substantial control over the efforts—at substantial effort and expense for the practitioners. I believe this is what much of the recent hubbub in Texas over adult stem cell treatments is about, but this blog is not big enough to delve deeply here.
I will say I think we should be careful about “scoreboards” of successes with adult vs embryonic stem cells. I find them misleading at best. If we are counting individual cases, that is not the same as approved therapies, and the number of individual successes is probably too low on the adult side without including the thousands of successful bone marrow transplants.
But in this context, the application of adult stem cells still appears to be expanding, and milestones like regulatory approvals should be noted by those interested in this area. And that, of course, is before we start talking about newer approaches, like iPSCs, to more “juvenile” stem cells.

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carol
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Sounds promising. Once there is more research done , the possibilities with stem cell therapy will be enormous-especially when using your own.