BAD news for those opposing embryonic stem cell research and
GOOD news for those favoring adult stem cell research:
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.'Dubious notion'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.
Those looking for proof of the validity of adult stem cell research should take heart ..... Congress would do well to take note in their deliberations next week!