Please note that this blog no longer accepts comments (there was
too much spam coming in!). If you're reading this blog and want to
respond then please use the contact form on the site.
You can also follow me on twitter.
My latest Mind and Matter column in the Wall
Street Journal is on stem cells:
The chief medical ambition of those who study stem cells has
always been that the cells would be used to repair and regenerate
damaged tissue. That's still a long way off, despite rapid progress
exemplified by the presentation of the Nobel Prize next week to
Shinya Yamanaka of Kyoto University for a key stem-cell
breakthrough. But there's another, less well known application of
stem cells that is already delivering results: disease
Dr. Yamanaka used a retrovirus to insert four genes into a mouse
cell to return it to a "pluripotent" state-capable of turning into
almost any kind of cell. Last month a team at Johns Hopkins
University and the Sloan-Kettering Institute for Cancer Research,
using a version of Dr. Yamanaka's technique, successfully grew nerve cells from a patient suffering from
a rare disease called Riley-Day syndrome, which is linked to early
mortality, seizures and other symptoms and caused by a fault in one
But the purpose was not to put these cells back into the
patient. Instead the scientists tested 6,912 chemical compounds on
the cells to see if they could find one that "rescued" the
"expression" of the gene: that is to say, caused it to produce the
protein it is supposed to produce. One of the compounds worked,
inducing the gene to be actively transcribed by the cell.
In the not-very-distant future, when something is going wrong in
one of your organs, one treatment may be to create some stem cells
from your body in the laboratory, turn them into cells of that
organ, or even rudimentary structures, and then subject them to
experimental treatments to see if something cures the problem. The
goal of personalized medicine, in other words, may be reached by
stem-cell researchers before it's reached by geneticists.
Further breakthroughs are coming thick and fast to bring that
goal closer. Just last week a team largely from Cambridge
University announced that they had grown abundant stem cells from particular
kinds of blood cells. Amer Rana and his colleagues isolated "late
outgrowth endothelial progenitor cells" from patients' blood and
then induced them to become stem cells, from which they will be
able to grow blood vessels. The first use will be to test drugs on
The advantage of these blood-derived stem cells, compared with
those derived from skin cells, is that they can be generated in
stable form in quantities that allow multiple drug testing. Dr.
Rana's team induced stem cells from both healthy people and those
with various kinds of a disorder known as pulmonary arterial
hypertension. Studying the differences and testing treatments comes
Until Dr. Yamanaka's breakthrough of five years ago, few
biologists held out much hope that the cells of an adult person
could be made into stem cells, in contrast to those of an embryo.
Debate still continues among biologists about whether
such adult cells approach the gold standard of adaptability that
embryonic stem cells show, but few would now bet against that goal
being achieved one day.
It's not far-fetched to conclude that, thanks to induced
pluripotent stem cells, the embryonic stem-cell debate is fading
fast into history. If stem cells derived from the patient's own
blood are to offer the same therapeutic benefits as embryonic stem
cells, without the immunological complication of coming from
another individual, then there would be no need to use cells
derived from embryos.
Indeed, that was one of Dr. Yamanaka's original motivations when
he set out to induce pluripotency in adult cells. Though he
supported embryonic stem-cell research in principle, he once said: "I thought, we can't keep
destroying embryos for our research. There must be another