Another 'Adult' Stem Cell Success Reported Ahead of Senate Debate
July 7, 2008 - 8:23 PM
(CNSNews.com) - A week before the U.S. Senate again grapples with the explosive issue of embryonic stem cell research, one of the most stunning reported advances in bio-technology in years comes from stem cells not harvested from human embryos but derived from a non-controversial source.
British researchers have for the first time grown part of a human heart, using "adult" stem cells derived from bone marrow, British media reported this week.
If trials in animals such as pigs and sheep prove successful later this year, the London-based team led by professor Sir Magdi Yacoub said such replacement tissue could be used in transplants for heart disease patients within three years.
Yacoub, professor of cardiac surgery at Imperial College, told The Guardian newspaper that a whole, functioning heart could be produced from stem cells within a decade, a goal he described as "ambitious ... but not impossible."
The researchers hope to grow a heart valve that will not be rejected by the patient's body - because the stem cells are the patient's own - and that will have a longer life than artificial (plastic or metal) valves currently being used in heart patients.
Using the tissue could ultimately preclude the need for a heart transplant, they said.
The researchers' achievements are due to be published in August in the Royal Society's Philosophical Transactions journal, in a special edition on "Bioengineering the Heart."
According to the U.N.'s World Health Organization, some 17.5 million people around the world died of cardiovascular disease in 2005 - 30 percent of all global deaths. Of those, an estimated 7.6 million deaths were due to coronary heart disease and 5.7 million to stroke.
The push to use stem cells to treat a range of diseases and injuries is at the forefront of modern bio-science endeavor, but the sourcing of the cells remains a pressing ethical issue.
Proponents of embryonic stem cell (ESC) research say cells from early-stage human embryos are likely to be the most effective and have the greatest potential to turn into many different types of cells ("pluripotency"), but the fact that the embryos are destroyed in the process makes the work highly controversial.
"Adult" stem cells from alternative sources, such as bone marrow, placentas, umbilical cords and nasal passages, are already reportedly being used in scores of treatments, and for many who oppose ESC research, this is the work that should receive more attention and more taxpayer funding.
Supporters of "adult" stem cell research also note that cells from a patient's own body do not share problems of rejection often experienced in the case of embryonic stem cells.
ESC research is being carried out in many parts of the United States, but largely with private funding, since President Bush in 2001 restricted federal funding to work on a limited number of then-existing ESC colonies.
Next Wednesday, the U.S. Senate is due to vote on a bill introduced by Senate Majority Leader Harry Reid, mandating federal funding for ESC research.
The House of Representatives passed a similar bill last January but will also have to vote on the Senate bill before it can be sent to the president.
Bush has already pledged to veto the bill, as he did with similar legislation last year.
Another bill before the Senate next Wednesday is an alternative sponsored by Sens. Norm Coleman (R-Minn.) and Johnny Isakson (R-Ga.), seeking federal funding for stem cell research that would not harm embryos.
The latest breakthrough, like many previous ones - including Australian trials that have reinjected patients' own stem cells into their hearts to repair damaged muscle tissue - uses "adult" cells, not embryonic ones.
But most media coverage of the news downplayed that fact, with the descriptor "adult" rarely appearing.
"As I always say: Most biotechnology is not controversial," bioethicist and Discovery Institute senior fellow Wesley J. Smith said in reaction to the news from Britain. "This is a wonderful example. Let us hope that the reality meets the dream."
Proponents of ESC research have frequently dismissed or downplayed the importance of "adult" cells.
Last year, the New England Journal of Medicine reported that while many hospitals around the world now routinely inject bone marrow stem cells into the blood vessels surrounding the heart to induce recovery of damaged heart muscle cells, the intervention offers little benefit.
In an article called "The Politics and Promise of Stem-Cell Research," NEJM deputy editor Robert Schwartz took issue with the White House position that "adult" stem cells offer far more promise than embryonic ones.
"The notion that adult stem cells have the same developmental potential as embryonic stem cells, let alone 'more promise,' is dubious," Schwartz wrote.
"There is evidence in laboratory animals that an adult stem cell can differentiate into a cell that normally belongs to a different/super /nosupersub lineage ... but such reports of a pluripotent stem cell that can transdifferentiate have been challenged," he said.
Meanwhile, at the University of Dusseldorf in Germany, scientists have found bone marrow stem cells useful in dealing with advanced cancer of the liver.
According to a study published in the April issue of the journal Radiology, some patients with advanced liver cancer cannot undergo surgery because removing the large cancer would leave too little of the liver - less than 25 percent - remaining to support the body's functioning.
Seven patients underwent a standard treatment involving diverting the blood supply from the cancerous part of the organ to the healthy part, while another six patients received that treatment plus an injection of liver stem cells taken from each patient's own bone marrow.
The latter six patients' livers grew twice as fast as the others, the doctors reported.
"Based on our results, we also believe that adult stem cell administration may be a promising therapy for regenerating livers damaged by other chronic and acute diseases," the journal quoted the study's co-author, Jan Schulte am Esch, as saying.
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