Dienstag, 7. Dezember 2010

Human experiments being held with potentially dangerous human embryonic stem cells


Dr. Edith Breburda

On October 11, 2010, the day the U.S. celebrates Columbus Day, the Shepherd Center, a 132-bed spinal cord and brain injury rehabilitation hospital and clinical research center in Atlanta, Ga., participated in an experiment for restoring sensation to people with spinal cord injuries.
They cooperated with Geron Corporation, a California based firm
that conducts “dubious embryonic stem cell research.” The firm announced it has treated the first time a patient with embryonic stem cells.
Human injected with cells
A human being had been injected with human embryonic stem cells, coming from human embryos left over from fertility treatments, explains Dr. Okarma, CEO director of Geron.
Seven potential sites in the United State enrolled patients in the clinical trial. Geron Corporation got the first U.S. Food and Drug Administration license to use the controversial cells to “treat” people.
The patients eligible for the phase one trial are those who have suffered a complete thoracic spinal cord injury between seven and 14 days ago. Patients in such conditions can still move their arms and breath on their own.
A ‘safety test’
However, the injected embryonic stem cells aren’t pure human embryonic stem cells anymore. The patient received precursor cells, un- or only partially differentiated cells, derived from human embryonic stem cells.
It is possible to make an abundant supply from the undifferentiated embryonic stem cells before treatment of an acute spinal cord injury. The hope of the Geron Cooperation is that the cells once inside the human body will finish specializing, then travel to the site of the recent spinal cord injury and release compounds that will repair the damage.
The whole trial was never set up to cure patients. It is only used to determine that the cells are safe to use. It is actually no more than a safety test to see whether the injections of precursor cells lead to tumors or other complications.
And it will take some time, perhaps many years. Still no one can be sure whether the stem cells really helped.
Meanwhile researchers who are looking at facts are convinced that adult stem cell therapies make experiments with embryonic stem cells wholly superfluous (Smith 2010).
Concerns about the trial
Scientists expressed concerns about Geron’s trial. The cells used were not completely differentiated, only partially differentiated (“precursors”). They actually did not inject human embryonic stem cells because science is still not able to overcome significant problems in their use with animals. Specifically, undifferentiated or partially differentiated embryonic stem cells cause tumors and are rejected by the immune system.
Researchers use different culture conditions in order to induce neuronal differentiation. They add Vitamin A, or use a so-called co-culture method. That means human embryonic stem cells are cultured in the Petri dish with already differentiated neuronal tissue.
“However, the neural induction process often requires direct contact of human embryonic stem cells with the stromal cells (connective tissue cells of an organ in order to release growth factors that promote cell division), which introduces unknown and potentially risky factors as most of these cell lines are tumorigenic,” explains Su-Chu Zang in his article: “Human embryonic stem cells for brain repair,” published at Biological Science 2007.
It is also common to isolate neural stem cells or progenitor stem cells from fetal brain tissue obtained from fetal tissue banks, which are using the remains (placenta, extra-fetal tissue….) of aborted children for medical research.
Adult stem cells better
Former Indiana State University biology Professor Dr. David Prentice accused Geron Corporation of falsely promoting its work as embryonic stem cell trials when derivates were used instead. “Geron is irresponsibly trying to do science by press release, publicizing that they have begun their human experiments by injecting a patient with potentially dangerous cells. Their press hype will help stock prices, but not science and not patients. We hope the patients don’t suffer any ill effects.
“It will be years before there is hard evidence about safety or effectiveness. If Geron truly wanted to help patients, it would stick to research and trials involving adult stem cells. They already are helping patients now who are battling dozens of diseases and medical conditions.”
Prentice continued: “Adult stem cells have published real scientific evidence for effectively treating spinal cord injury.”
First application is flawed
Professor Dr. John A. Kessler, chairman of neurology and director of the stem cell institute at Northwestern University announced that the first application from Geron for the embryonic stem cell trial was flawed.
Already in 2008, Evan Synder, a neuroscientist, head of the Stem Cell Research Center at Burnham Institute for Medical Research in San Diego, warned that the research is not ready for humans.
About the Geron trial Synder noticed that the mice used to conduct pre-human trial research had excessive injuries. And the company should have done experiments involving larger animals before seeking FDA permission.
Moving too fast?
Did Geron moved too fast? Jerry Silver, a neuroscience professor and stem cell researcher at Case Western Reserve University in Cleveland, is absolutely convinced they did.
He is not alone with that view. “Nobody can conceive of a human trial with the use of human embryonic stem cells following immediately from experiments in rodents only,” explains Jerry Silver.
Many spinal cord researchers acknowledge that the pre-clinical data itself doesn’t justify the clinical trial. They know too well that science revealed that many treatments actually worked well with rodents (or even only in rodents) but failed miserably in humans (Ertelt 2010).
Literature:
Breburda E., Verheißungen der neuesten Biotechnologien. Christiana Verlag, Stein am Rhein, ISBN-10: 3717111728, 160 pages 39,80 Euro.
Breburda E., Promises of new Biotechnologies. Unpublished Manuscript 2010
Smith W.J., First human embryonic stem cell treatment commences. First Things, Monday, October 11, 2010
Ertelt S., Company claims first patient treated with embryonic stem cells, not the case. LifeNews.com, October 11, 2010

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