Notes from Dr. Regner's Presentation on Stem Cells
by Carl Kaun
Dr. Kurt Regner, an Assistant Professor in the School of Life Sciences
at UNLV, spoke to Halvason members about stem cell research this past
Sunday, October 15, 2005.
Dr. Regner started by drawing a diagram illustrating the stages that
researchers expect to apply in a therapeutic use of stem cells.
The first stage in the process is to use a microscopically thin needle
to remove the nucleus from a patient's (e.g. skin) cell, and to place
that nucleus in an egg whose nucleus has been similarly removed.
The environment surrounding the egg is then manipulated to cause the
egg cell to divide, resulting in at first two cells, then four cells,
then eight, and so on. An eventual result of this division is a
group of cells called a blastocyst, which contains some (partially)
differentiated cells and some stem cells. The stem cells are
removed from the inside of the blastocyst and placed in a culturing
medium, which Dr. Regner displayed as a flask. In the culturing
medium, the stem cells can divide somewhat indefinitely. To be
used in a therapy, the stem cells are caused to differentiate into one
of about 220 kinds of tissue, which is inserted into the patient (e.g.
by surgery) to improve the patient's condition.
The differentiation process is the most complex part of the process,
and involves dozens of steps, entailing exposure to specific
combinations of proteins at each. Accomplishing this
differentiation is the only stage of the process that has not been
completed for humans, and the one in which research is being most
actively pursued.
Dr. Regner explained that stem cells are so called because other types
of cells can result from, or "stem from" them. Embryonic stem
cells produced in the manner described above can differentiate to
produce every other kind of (human) tissue. They are, in other
words, fully pluripotent. In contrast, adult stem cells -- taken
from a developed person -- are partially differentiated, and can
produce only certain other kinds of tissue. Umbilical stem cells
are similarly partially differentiated, and can produce only skin,
blood, and bone tissues.
Dr. Regner also observed that adult and umbilical stem cells are not as
"growable" as embryonic stem cells, in that they cannot be nurtured for
more than about 40 hours.
The question was asked why stem cell researchers believe they can take
the final step in the process described previously, to produce human
tissues from stem cells. Dr. Regner replied that researchers have
nearly accomplished this final step for other species, notably the
production of mouse neurons, and there is no known reason why the same
should not be possible using the same general approaches for human
tissues, even though the exact steps in the process remain to be worked
out.
In vitro fertilization is a process in which an egg is fertilized with
a sperm, and then divides and eventually produces a blastocyst.
Fertility clinics then insert the blastocyst into a woman's uterus,
where it attaches and goes on to develop into a fetus, and eventually
is born as a baby. Stem cells can be withdrawn from a blastocyst
produced by in vitro fertilization in exactly the same manner as
described previously, and indeed all existing stem cell lines have been
obtained in exactly this manner. Similarly, a blastocyst
resulting from the introduction of a person's cell nucleus into an egg
would, if implanted in a woman's uterus, go on to be born as a clone of
the person. Perhaps because of these similarities, Dr. Regner was
very noncommittal about exactly what the word "conception" meant, and
also when life begins, suggesting that it may mean different things to
different communities of people.
At one point in the discussion, Dr. Regner noted that we, the audience,
had as thorough an understanding of stem cell research as the President
and the members of Congress.
Dr. Regner went on to address the political climate surrounding stem cell research.
President Bush in 2001 authorized federal funding of stem cell
research, at the same time limiting that funding to 70 existing stem
cell lines, and declaring that he would not sanction processes
violating the dignity of human life. By that he meant
approximately the destruction of human embryos.
In July 2006, President Bush vetoed H.R. 810, which would have funded
broader stem cell research, on the grounds that this would have funded
the deliberate destruction of human embryos, a moral line he would not
allow our Nation to cross.
The President has signed the Fetus Farming Prohibition Act, which
prohibits trafficking in human fetuses that are created with the sole
intent of aborting them to harvest their parts. In contrast with
many foreign governments, this is the only law in the U.S. remotely
related to fertility research. Dr. Regner noted moreover, that
this Act has no impact on the use of stem cells (which never become
fetuses), and that in requiring intention it addresses a situation no
one has ever intended to create. But it did resonate with some
voters.
While the federal government is hostile to stem cell research, there is
nothing to prevent private stem cell research, and indeed the
pharmaceutical industry is funding heavily in the area.
Additionally, while some states are like the federal government in
their hostility to stem cell research, other states, like California,
are considering investing in it, or at least incentivizing it.
Several other countries are also actively pursuing stem cell research,
China, Singapore and South Korea notably among them.