Company Says It Can Derive Stem Cells From the Placenta
April 12, 2001
By NICHOLAS WADE [NYT]
A New Jersey company said yesterday that it had developed a method to extract a novel kind of
stem cell from the placenta and that the cells were the equivalent of human embryonic stem cells,
which can transform into every tissue of the adult body.
"This will make obsolete the need to use human fetuses or blastocysts as sources of stem cells," John
Haines, chief executive of the Anthrogenesis Corporation of Cedar Knolls, N.J., said.
The assertion comes as opponents of abortion encourage the Bush administration to bar federal
financing for research on embryonic cells, which are now derived either from very early human
embryos, known as blastocysts, or from fetal tissue. These critics seem unlikely to object to research
on cells from placentas.
But the articles describing the research have not yet been accepted for publication, an important step in
the validation of scientific claims.
Biologists believe embryonic cells hold great promise for restoring damaged tissues, particularly in
otherwise intractable diseases like Alzheimer's and Parkinson's.
Embryonic stem cells differ from adult stem cells, which are found in the various adult body tissues they
help maintain. This week, a different group of researchers said it had isolated adult stem cells from fat
tissue. But adult stem cells, which also offer a promising way of repairing damaged tissues, differ in
many ways from embryonic stem cells. Biologists are eager to explore both.
The Anthrogenesis scientists believe that they have found a possible new source of embryonic stem
cells, though they cannot yet prove that their cells are embryonic in nature. The two known sources of
embryonic cells are the blastocyst, a hollow sphere of cells produced a few days after an egg is
fertilized, and fetal tissues that hold the future germ cells of the ovary and testis.
Within the blastocyst is a clump of cells known as the inner-cell mass, from which all the tissues of the
fetus are generated. Some of these cells migrate to the ovary and testis and can be recovered from fetal
tissue. Known as embryonic germ cells, they closely resemble the embryonic stem cells that can be
derived from the inner-cell mass.
The Anthrogenesis scientists believe that some inner-cell mass cells also migrate to the placenta and are
held there as a reserve in case the fetus needs them. If so, this would be a third source of
embryonic-like cells.
Other experts said that this was a novel and interesting idea but that they knew of no evidence to
support it, and Dr. Joseph Cioffi, the company's director of research and development, agreed there
was no animal data bearing on the issue.
The company calls its cells placental multipotent stem cells — multipotent, a characteristic of embryonic
stem cells, because they can be induced to form several different kinds of mature cells, in this case
those of cartilage, nerves and the lining of the blood vessels.
The company, though, has not yet examined its cells for a characteristic protein found in embryonic
cells that is known as the oct4 marker. Nor has it shown that every type of mature cell can be derived
from a single starting cell, a rigorous test of a stem cell's properties.
Anthrogenesis derives its cells by removing blood from the placenta and keeping a certain part of the
placenta alive, though the company declined to give its anatomical name. The placental multipotent stem
cells can be harvested in large numbers from this preparation, company officers said.
Dr. John Gearhart of Johns Hopkins University, who was the first to derive human embryonic germ
cells, said that it was impossible to remove all blood from the placenta and that the company had yet to
prove that its cells were different from blood-making stem cells, a kind of adult stem cell.
A company official said such proof lay in the fact that the cells did not produce a marker called CD34,
but Dr. Gearhart called this definition outmoded and said that young blood- forming stem cells were
now known to lack this marker.
If further tests should prove that the placental cells are a satisfactory substitute for embryonic stem cells,
the company's finding could influence the political debate.
The National Conference of Catholic Bishops has opposed government financing of research on both
human embryonic stem cells, taken from blastocysts, and embryonic germ cells, derived from fetuses
aborted for the health of the pregnant woman.
Yesterday, Richard Doerflinger, a policy official at the bishops' conference, said he saw no ethical
problem in using cells derived from the placenta of live births.
Copyright 2001 The New York Times Company |
