IT HAS BEEN REPEATED so often that it is now a mantra: "Embryonic stem cells offer the most promise for finding cures" for degenerative diseases and conditions such as Parkinson's disease and spinal cord injury. But saying something ten thousand times doesn't make it true. Indeed, the embryonic stem cell mantra has yet to be demonstrated scientifically.
More than that, the actual data published to date in peer-reviewed science journals tell a far different story. While there have certainly been successes in embryonic stem cell experiments in animal studies--many of them hyped to the hilt in mainstream media reports--the numbers pale in comparison with the many research advances being made with adult and umbilical cord blood stem cells, which are already being used in human patients.
Based on the published science, there are 72 maladies for which human patients have received some benefit (which is not the same as being "cured") from adult stem cell or umbilical cord blood interventions. Meanwhile, embryonic stem cells have yet to demonstrate any human therapeutic use.
This is not to say that embryonic stem cells don't have genuine scientific value. Researchers are excited about the prospect of gaining a more fundamental understanding of developmental biology by experimenting on embryonic stem cells, for example. And embryonic stem cells may well have the capacity to treat human diseases. But to win the current political debate over federal funding of embryo-destructive research, many supporters have made extravagant claims about pending cures. In their zeal, they forget to mention that embryonic stem cells cannot be used safely in human beings at present because of worries over tissue rejection and their demonstrated propensity in animal studies to cause deadly tumors--problems not associated with adult stem cell therapies.
Some adult/umbilical cord stem cell treatments are now deployed in routine clinical practice. But most remain experimental. For example, as reported in the March 2005 edition of the science journal Blood, Stage 2 trials are currently underway in human patients with "severe" multiple sclerosis using the patients' own blood stem cells. After three years, the study reported, adult stem cells were "able to induce a prolonged clinical stabilization in severe progressive MS patients," meaning the disease stopped advancing, "resulting in both sustained treatment-free periods and quality-of-life improvements."
Another area of great hope for adult stem cell therapy comes from using a patient's olfactory tissues, found in the nasal cavity, to treat paralysis caused by spinal cord injury. Peer-reviewed animal studies previously highlighted great potential for this technique. For example, olfactory tissues have "promoted partial resto r ation of function" in paralyzed rats.
Human studies in this area have been ongoing for several years. In June, Dr. Carlos Lima from Portugal published his first findings in the Journal of Spinal Cord Medicine. Of the first seven paralyzed people he treated, "two patients reported return to sensation of their bladders and one of these regained voluntary contraction of anal sphincter." Most "recovered sensation below the initial level of injury." Moreover, "patients exhibited a modest amount of improvement in function that is not normally observed in complete SCIs [spinal cord injuries]," leading to the conclusion that olfactory mucosa "may possibly promote functional recovery in chronic, severe SCI in humans." (Further human trials have now commenced using olfactory tissue in Britain, Italy, and Japan, among other countries.)
If Lima had used embryonic stem cells to help human patients recover some sensation after spinal cord injury, the headline in the New York Times would have been printed two inches high in red ink. The report would have been cited far and wide as proof that the late Christopher Reeve was right when he (incorrectly) claimed that embryonic stem cells offered him his "only hope" for recovery. Yet, even though Lima's report is important--with anecdotal evidence of even more encouraging results in subsequent patients--the Times, the Washington Post, and other mainstream outlets have yet to report on the study.
There is a reason for the news blackout about the many encouraging advances in adult stem cell science. Worried that adult/umbilical cord blood research successes might tip public support away from embryonic research, proponents of federal funding for embryonic stem cell studies, aided by a compliant press, have mounted a vigorous campaign to downplay adult stem cell research.
Toward this end, an unfair and demagogic attack was recently published in Science against biologist David Prentice--who has done more than any other person to bring adult stem cell research progress to the public's attention--and the Do No Harm Coalition, which Prentice helped found to keep track of and analyze stem cell research literature.
Specifically, embryonic stem cell and human research cloning proponents Shane Smith, William Neaves, and Steven Teitelbaum in their letter in Science accused Prentice of being "deceptive" for claiming that "adult stem cells have now helped patients with at least 65 different human diseases." But Prentice's modest claim is absolutely true (with the number now having reached 72) and based on scientific reports published in peer-reviewed journals. Moreover, Smith, Neaves, and Teitelbaum are the actual deceivers: They accused Prentice of promoting "the falsehood that adult stem cells are already in general [clinical] use," when he has never made any such claim.
Their letter continues the scientific establishment's efforts to keep adult stem cell research successes from being an issue in the stem cell and cloning debates. "Adult stem cell treatments fully tested in all required phases of clinical trials and approved by the U.S. Food and Drug Administration are available to treat only nine conditions," they sniff.
This is disingenuous. Many ad vances in adult stem cells are being made overseas, which by definition precludes their receiving FDA approval. Moreover, by their logic, neither the MS nor olfactory tissue research successes cited above should be mentioned in public discourse, since these hopeful avenues of science have not yet completed "all required phases of clinical trials." Nor, for that matter, should we inform the public that the FDA's databank shows that there are more than 500 approved human trials active or recruiting for patients in this country using adult stem cells, with more than 1,100 such approved experiments in all--versus zero for embryonic studies.
On the other hand, if it is only acceptable to discuss stem cell treatments that have actually entered medicine's clinical armamentarium with full FDA approval, embryonic stem cell-boosting scientists and their boosters in the media had better stop chanting the embryonic stem cell mantra.
Embryonic stem cells have not treated a single human patient, and only time can tell whether they ever will. Highlighting the progress of adult/umbilical cord blood stem cells--an uncontroversial therapeutic approach that does not require the destruction of human embryos--is a legitimate part of the public discourse. Indeed, the unfair attack on Prentice for educating the public about the potential of adult stem cells may indicate that these scientist/political advocates know where the true best hope for regenerative medical treatments is likely to be found.
Wesley J. Smith, a frequent contributor to THE WEEKLY STANDARD, is a senior fellow at the Discovery Institute and a special consultant to the Center for Bioethics and Culture.