Scientists create embryonic cells from skin cells
By Maggie Fox, Health and Science Correspondent
WASHINGTON (Reuters) – Scientists have created a human
embryonic stem cell from ordinary skin cells and say it is a
step closer to tailored medical treatments without the
technical difficulties or the controversy of using human
embryos.
The scientists said on Monday their technique, in which
they fused embryonic stem cells to skin and bone cells, could
one day provide the scientific and medical benefits of
so-called therapeutic cloning.
But stem cell experts Kevin Eggan, Dr. Douglas Melton and
colleagues at Harvard Medical School and the Howard Hughes
Medical Institute stress in a report to be published in next
Friday’s issue of the journal Science that their method is not
yet ready to try in humans.
“This technique is not ready for prime time now,” Eggan
told reporters in a telephone briefing, adding that he feels
cloning technology, the use of discarded embryos from fertility
clinics and other approaches are all still vital.
The newly fused cells contain DNA from both cells.
Therefore, they would not be a perfect genetic match to the
patient.
Stem cells are the body’s master cells, used to continually
regenerate tissues, organs and blood. Those taken from days-old
embryos are considered the most versatile. They can produce any
kind of tissue in the body.
Doctors hope to someday use embryonic stem cells as a
source of perfectly matched transplants to treat diseases such
as cancer, Parkinson’s and some injuries. Biologists want to
study them to understand the basic causes of disease and
development.
But because some people, including President George W.
Bush, object to the destruction of or experimentation on a
human embryo, U.S. law restricts the use of federal funds for
this kind of research.
It is a hot debate in the U.S. Congress and several bills
have been offered for consideration when the Senate comes back
next month that would either relax the federal restrictions or
tighten them even more.
“There still could be some groups of people that would
object to (our method) because at one time the cells were
derived from a very early human embryo,” Eggan said.
GETTING AROUND RESTRICTIONS
His team worked with stem cells created using both private
and federal funding.
They fused embryonic stem cells to human adult skin cells,
and managed to reprogram them back to an embryonic state. The
new cells acted like stem cells, forming tumors called
teratomas when injected into mice — a classic test for a true
embryonic stem cell. They also contained genes unique to stem
cells.
The cells also appeared to survive indefinitely in a lab
dish, another test of a true embryonic stem cell.
“We found they could be induced to mature into nerve cells,
hair follicles, muscle cells and gut endoderm cells. And when
cultured in lab dishes, the cells differentiated, or matured,
into the three major basic types of cell,” Eggan said.
Eggan said the work was not inspired by the political
debate.
“Our motivation is completely based in science,” Eggan
said.
“Myself and my colleagues feel very, very strongly that
research with somatic cell nuclear transfer (so-called
therapeutic cloning) should move forward. We feel it is
critical.”
Eggan’s team and others say they ultimately wish to
understand how to re-program an ordinary cell and hope the use
of human embryos would only be an interim step to learning how
to manufacture these cells.
Currently, embryonic stem cells are either taken from
embryos left over from fertility clinics, or generated using a
cloning technology called nuclear transfer. This requires
taking the nucleus out of an egg cell and replacing it with the
nucleus of an adult cell, called a somatic cell, from the
person to be treated.
When done successfully, the egg starts dividing as if it
had been fertilized by a sperm.
“If one could just simply understand how that process
works, termed reprogramming, one might be able to directly turn
adult cells into embryonic stem cells without an embryo or an
egg,” Eggan said.