Have You Heard the Good News . . .
. . . about adult and umbilical cord blood stem cells? Probably not.
12:00 AM, Sep 29, 2005 • By WESLEY J. SMITH
WE HAVE HEARD IT STATED SO OFTEN it has become a media mantra: Embryonic stem cells (ESCs) offer the greatest hope for cures; adult and umbilical cord blood stem cells have far less potential; the Bush administration's embryonic stem cell funding restrictions have caused America to fall behind in the great international race to develop effective ESC treatments.
Baloney, baloney, and pure baloney: The problems with harnessing embryonic stem cells as treatments appear to be growing, not shrinking. For example, ESC boosters used to claim that these cells are "immortal," that is, they can be maintained indefinitely in culture to provide an inexhaustible source of cellular treatments. Well, not quite: Recent studies have demonstrated that over time ESC lines develop chromosomal abnormalities similar to those found in some cancers. This means that the useful shelf life of embryonic stem-cell lines is probably limited.
Moreover, the oft-heard assertion that ESCs can be used to create "any kind of cell in the body" remains poorly grounded scientifically. For such a bald assertion to be true, it would have to have been actually accomplished in repeated experiments. It hasn't been. Few researchers have been able to differentiate an embryonic stem cell into the precise kind of cell they were seeking, and only that kind of cell. In most cases, attempts to morph ES cells into specific cell types have resulted instead in Petri dishes containing a wide variety of unwanted cells.
Animal experiments suggest that these proliferation difficulties may be the cause of the tumors so often seen when animals are injected with ESCs. This tendency to cause tumors is only one of the many problems that prevent researchers from using ESCs in human patients--problems widely expected to take many years to overcome, if they ever can be.
By contrast, the umbilical cord blood and adult stem-cell breakthroughs keep on coming. Human trials are ongoing for heart disease, spinal cord injury, eye afflictions, and many other diseases. And here's a bit of potentially very big news: A just-published peer-reviewed study (Cytotherapy, Vol. 7. No. 4 (2005), 368-373) reports that scientists have used umbilical cord blood stem cells to restore feeling and mobility to a spinal cord injury patient. The patient had been paraplegic (complete paraplegia of the 10th thoracic vertebra) for 19 years. The researchers report that after receiving an infusion of umbilical cord blood stem cells,
[t]he patient could move her hips and feel her hip skin on day 15 after transplantation. On day 25 after transplantation her feet responded to stimulation. On post operative day (POD) 7, motor activity was noticed and improved gradually in her lumbar paravertebral and hip muscles. She could maintain an upright position by herself on POD 13. From POD 15 she began to elevate both lower legs about 1 cm, and hip flexor muscle activity gradually improved until POD 41.
In other words, she regained feeling and some mobility after nearly 20 years of being paralyzed. (Similar results for patients with spinal-cord injuries have been reported in human trials in Portugal using the patients' own olfactory (nasal) stem cells--these studies have not yet been published in a peer-reviewed journal, though the very promising results in the first American patients have been testified to in a Senate subcommittee hearing and featured on the PBS television series Innovation.)
It is true that we have to be cautious about this. One apparently-helped paralyzed patient does not a broad efficacious treatment make. Also, the authors note that the woman also received a laminectomy (spinal surgery to release pressure) that could have provided her some benefit. Still, they report, not only did their patient regain feeling after years of numbness, but "41 days after [stem cell] transplantation" testing "also showed regeneration of the spinal cord at the injured site." (emphasis added)
THIS IS A WONDERFUL STORY that offers tremendous hope for paralyzed patients and their families. But as is usually the case with-non embryonic stem-cell research breakthroughs, you could hear the crickets chirping at the New York Times and in most other mainstream media outlets. Indeed, these publications are more likely to publish stories about mouse experiments using ES cells than about promising human trials using adult or umbilical cord stem cells.