2005-05-19 (Science Online)
Scientists
have created nearly a dozen new lines of human embryonic stem (ES)
cells that
for the first time carry the genetic signature of diseased or injured
patients.
The breakthrough represents a dramatic increase in the efficiency of
creating
such lines and may eventually pave the way for treating conditions such
as
spinal cord injury with stem cell transplants.
Last year,
a group led by veterinarian Woo Suk Hwang and gynecologist Shin Yong
Moon at
Seoul National University reported the first derivation of ES cells
from human
nuclear transfer (Science,
12 March 2004, p. 1669)--a process that involves replacing an oocyte's
nucleus
with one from a different cell, and then chemically kick-starting
development
of the egg. But those efforts yielded just one cell line from more than
200
tries.
In the new
study, reported online today in Science
(article is free with registration), the same team increased their
efficiency
more than 10-fold and can now derive cell lines in more than 1 in 20
tries.
Part of the secret is that they used freshly-harvested oocytes from
young,
fertile women instead of oocytes left over from fertility treatments.
In nine
cases, it took only a single donation of oocytes from a woman to
produce a new
line. Nine of the 11 cell lines are derived from patients who have
suffered
spinal cord injuries, ranging in age from 10 to 56. The other lines are
derived
from 2-year-old boy with a genetic immune disorder and a 6-year-old
girl with
Type-1 diabetes.
Hwang
cautions that his team remains years away from transplanting the cells
into
people. "We have to be over-convinced" that the cells are safe, he
says. However, the cell line derived from the diabetes patient should
be of
great interest to scientists.
"The
possibility of being able to study disease in a culture dish is very
exciting," says Douglas Melton, who has recently received permission
from
a university ethics committee to derive ES cells from diabetes patients
in his
laboratory at Harvard. "For the first time, we will have a chance to
study
the root causes of the disease."
The new
results may also influence the ongoing political debate over whether
research
with human embryonic stem cells, cloned or not, is ethically justified.
"Some people will hate it, others will love it," says Rudolf Jaenisch
of the Massachusetts Institute of Technology. "But it puts the
discussion
on a very firm footing now. People will have to rethink the argument
that it's
not efficient."
URL:
http://sciencenow.sciencemag.org/cgi/content/full/2005/519/1