150 stem cells lines needed for British therapeutic bank

By Patricia Reaney

LONDON (Reuters) – Scientists have calculated that about
150 stem cell lines derived from embryos would be needed to one
day establish a therapeutic stem cell bank in Britain.

“The study, although a simulation of the projected
requirements, provides the UK Stem Cell Bank with initial
targets for the population of a bank that could meet long term
therapeutic objectives,” Justin St John said.

The lecturer at the University of Birmingham in England
said in a commentary in The Lancet medical journal where the
findings were published on Friday that the scale of what needs
to be done is now clearer.

Stem cells have the potential to provide new therapies for
diseases ranging from cancer and diabetes to Alzheimer’s
disease and spinal cord injuries.

Britain set up the world’s first stem cell bank in May 2004
to store and supply the cells for research and ultimately
treatments for human illnesses.

Although stem cell therapies are still many years away,
scientists have tried to estimate the number of stem cell lines
– reservoirs of cells derived from single human embryo — that
would be needed to match recipients in the most cases.

“We found that about 150 donors would give a very good
match for about one in five recipients,” Professor J. Andrew
Bradley, of Addenbrooke’s Hospital in Cambridge, England, told
a news conference.

That number would also provide a modest match for about 90
percent and an intermediate tissue match for about 50 percent
to 70 percent of patients.

The researchers also identified a sub-set of stem cells
from 10 human embryos that could theoretically provide a very
good match for about 38 percent of recipients.

MULTIPLE RECIPIENTS

Like donor organs, stem cells from a therapeutic bank need
to be matched to the recipient as closely as possible to
minimize the risk of rejection and the need for
immunosuppressant drugs.

But unlike a heart, lung or liver transplant, which is
provided by one donor for one patient, a single stem cell line
could be used for multiple recipients.

The use of embryonic stem cells is controversial because
the master cells that can form into any cell type in the body
are derived from spare in-vitro fertilization (IVF) embryos.

Bradley and his colleagues, who reported the findings in
The Lancet medical journal, estimated the number of stem cell
lines needed by analyzing the blood group and tissue types of
10,000 organs donors for their compatibility to 6,577 patients
registered on the British kidney-transplant waiting list.

“A bank of 150 donors provided the maximum utility,”
Bradley explained, adding that full matches were found for only
2 percent of black and Asian recipients.

Last week British finance minister Gordon Brown announced
the country would double spending on stem cell research to 100
million pounds over the next 2 years. Part of the funding will
be used to support the stem cell bank.

Britain, along with South Korea, Singapore and the United
States, is one of the leaders in stem cell research. Spain, the
United States, Singapore also have plans for stem cell banks.

(Additional reporting by Ben Herschel in London)