April 1, 2011
Posted by admin
Following are excerpts from a Reuters story that ran on March 31, 2011; it includes quotes from an interview with ACT’s Chief Scientific Officer, Dr. Robert Lanza.
The original article may be found here.
ANALYSIS-Imperfections mar hopes for reprogrammed stem cells
31 Mar 2011 19:12
Source: Reuters // Reuters
* Reprogrammed stem cells rife with mutations, problems
* Embryonic stem cells still “gold standard”
By Julie Steenhuysen
CHICAGO, March 31 (Reuters) – When scientists announced five years ago
they could reprogram ordinary skin cells into behaving like embryonic
stem cells, religious conservatives and others who opposed the use of
stem cells cheered the advance.
But while they have proven to be a powerful new way to study human
disease, the reprogrammed cells — known as induced pluripotent stem
cells, or iPS cells — are no substitute for embryonic stem cells.
“This has strong policy implications,” Dr. George Daley of the Harvard
Stem Cell Institute and Harvard Medical School said in a telephone
“It has not ever been a scientifically driven argument that iPS cells
are a worthy and complete substitute for embryonic stem cells,” Daley
said. “Those arguments were always made based on political and
religious opposition to embryonic stem cells.”
Scientists typically harvest embryonic stem cells from leftover
embryos at fertility clinics. But the issue has been a point of
controversy for some religious conservatives, who believe the
destruction of any human embryo is wrong.
When they were first discovered in 2006, induced pluripotent stem
cells looked like a perfect solution to this ethical debate.
Instead of destroying an embryo, iPS cells are made in a lab from
ordinary skin or blood cells. Using various methods, scientists
introduce three or four genes that return these cells to an
embryonic-like state in which they, too, are able to turn into any
type of cell.
And because iPS cells can be made with tissue from people with known
genetic diseases, scientists can use them to study how diseases
develop or to test the effectiveness of drugs.
But recently, scientists have started to raise concerns about iPS cells.
Last year, a group led by Dr. Robert Lanza, chief scientific officer
of Advanced Cell Technology, compared batches of iPS cells
to embryonic stem cells and noticed the iPS cells died more quickly
and were much less capable of growing and expanding.
“It was the first study showing there were problems. No one wanted to
believe it,” Lanza said in a telephone interview.
In July, Daley’s team reported more problems in the journal Nature,
showing that iPS cells retain a bit of memory of their prior life as
adult tissue, which could limit their use.
And earlier this month, an international team led by researchers at
the University of California San Diego found genetic mutations in 22
iPS cell lines taken from seven different labs.
“There are serious problems with this iPS cell technology that still
need to be solved,” Lanza said.
He said abnormalities in iPS cells could raise flags among regulators
that these cells could cause problems in people.
Advanced Cell won U.S. Food and Drug Administration approval last year
for a clinical trial to treat a progressive form of blindness called
Stargardt’s macular dystrophy, and in January it won FDA approval to
start using embryonic stem cells to treat macular degeneration.
Those followed Geron Corp’s success last year in winning the
FDA’s nod for the first-ever approved study of human embryonic stem
cells to treat people whose spinal cords have been crushed.
“The gold standard cells at the present time are embryonic stem
cells,” Lanza said.
But the political path for embryonic stem cells is still murky. The
Obama administration overturned the strictest of the limitations
imposed by former President George W. Bush on using federal funds for
the research, but last summer that policy was challenged in court.
A U.S. appeals court has ruled that funding could continue while the
government appeals, but grants from the National Institutes of Health
have been frozen and unfrozen and the court battles are continuing.
Stem cell scientists are not giving up on iPS cells, but instead of a
replacement for embryonic stem cells, they see them filling a unique
(Editing by Michele Gershberg and Eric Beech)