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Stem Cell Updates

christianbrugger.jpgA few encouraging stem cell updates.  First, last month the online journal Nature published the results of experiments in mice by a team at the Harvard Stem Cell Institute in which common cells in the pancreas were converted into more precious insulin producing cells, precisely the kind that diabetics need to survive.  And the most extraordinary thing: the conversion took place inside the body of the living mice.

The Harvard scientists identified three molecular switches that when flipped converted one type of fully developed adult cell completely into another type.  Because the biology of pancreatic development in mice is similar to humans, there is optimism that the results will be repeatable in humans, though Doug Melton the team leader cautioned that human diabetic cures still lay many years off.  Other scientists have begun using the approach on cells related to the treatment of spinal cord injuries and Lou Gehrig’s disease (see http://www.washingtonpost.com/wp-dyn/content/article/2008/08/27/AR2008082701 829.html ).

Second, a very important breakthrough in the production of “induced pluripotent stem cells,” or iPS cells, was announced at the end of September.  Recall that Shinya Yamanaka of Kyoto University in Japan announced last November that his team had successfully converted adult skin cells into pluripotent stem cells functionally identical to embryonic stem cells using a cocktail of four genes injected into the skin cell’s nucleus.  The one stark problem with the procedure at the time was with the delivery system of the four genes.  They were carried on the back of retroviruses that potentially cause cancer.  On September 25 the online journal Science published the results of a study headed by Konrad Hochedlinger of Harvard showing that the same four genes could be delivered into the cell using adenoviruses, which unlike retroviruses present little risk of cancer.  The problem of the retrovirus delivery system was one of the biggest obstacles to transferring the approach into human clinical trials.  There is hope that this new breakthrough might facilitate the process (see http://www.washingtonpost.com/wp-dyn/content/article/2008/09/25/ AR2008092502099.html ).
Finally, three successes in adult stem cell therapy were reported in the final week of September and posted by my friend David Prentice on his informative blog (available at www.frc.org [1]).  The first, published in the American Journal of Gastroenterology, was a study showing that seven of nine patients suffering from alcoholic cirrhosis of the liver, when treated with adult stem cells from their own bodies, expressed significant improvements; and three of the seven showed almost complete recovery.  The second study was published in the Proceedings of the National Academy of Sciences by a team at Texas A&M.  It showed that when stem cells from human bone marrow were injected into the brains of stroke-induced mice, the adult stem cells caused a reversal in the nerve damage caused by the stroke.  This gives hope that strokes in humans and other diseases of the brain may one day be able to be treated by stem cell therapies that promote the growth of neural tissue. The third, published in the journal Molecular Therapy, showed that when adult bone marrow stem cells were injected into the muscle of rats suffering from Lou Gehrig’s disease (ALS), it prolonged the lifespan of the rats.  The adult stem cells were engineered to carry a gene responsible for stabilizing and maintaining the connections between nerves (ALS is a progress nerve degeneration disease).  The gene-carrying stem cells appeared to strengthen the existing neural connections delaying the progression of the disease.  Presently there is no effective treatment for ALS.
While these encouraging advances continue to unfold in research using adult stem cells and iPS cells, clinical research with embryonic stem cells continues to be bogged down with problems from tumor formation.  Given that mounting evidence is being amassed for the concrete clinical benefits of adult stem cells for a wide range of diseases; and given that the coveted property of pluripotency of embryonic stem cells is almost identically expressed by non-controversial iPS cells; and given that embryonic stem cells despite hundreds of millions of dollars having been spent on them continue clinically to disappoint; isn’t it time for the scientific community to leave human embryos alone and invest its full energy in morally legitimate alternatives that promise equal if not more clinical benefit?

Despite these positive breakthroughs, both Senators Obama and McCain continue to say publicly that they support federal funding for destructive research on IVF embryos.  McCain usually qualifies his formulations of support with statements such as ‘clear boundaries need to be drawn that protect ethical principles;’ but in the end he states his support—as he did on Sept. 19 in an interview with Science Debate 2008: “I support federal funding for embryonic stem cell research.”  A U.S. bishop who recently met with McCain told me that the senator said he was ‘carefully considering the issue in light of recent scientific breakthroughs’.  I presume McCain is referring to breakthroughs with adult stem cells and with alternative sources for deriving pluripotent stem cells.  Do we have reason to believe that a President McCain would revise his position after taking office?  Nobody I know can answer that question.


Dr. Chirstian E. Brugger [2]   is Senior Fellow in Ethics of the Culture of Life Foundation


Copyright 2008.  Reproduction granted with attribution required .