September 9, 2005

Animal-human transplants soon to be reality -expert

By Patricia Reaney

DUBLIN (Reuters) - Transplants of animal organs into people
could take place within a few years because of the acute
shortages of donated human organs, a leading scientist said on

"It is only in recent years that many of the potential
immunological problems, such as transplant rejection, have been
solved, meaning the process of transplanting organs from one
species into another could soon be a reality," said Dr Anthony
Warrens, of Imperial College London.

Warrens told the British Association for the Advancement of
Science conference in the Irish capital that for every donated
human organ that became available there were five people who
needed it.

Xenotransplantation, the use of organs, tissues or cells
from a different species, is thought to be the best solution.

Pigs are a likely source of transplant organs because they
are about the same size as humans and have a similar
physiology. Scientists are working to produce genetically
engineered pigs whose tissues would not provoke an immune
response in humans.

Scientists do not know if "porcine endogenous retroviruses"
can be transferred to humans, or if they can mutate and cause
new diseases.

"That remains the principal anxiety associated with
xenotransplantation," said Warrens.

But he added there was good reason to believe it would not
be a major problem. Many scientists have called for a
moratorium on xenotransplantation until such dangers have been

Once scientists have got to the point of starting clinical
trials, which could be about five years away, patients
receiving the organs will have to be monitored daily for life,
according to Warrens.