'Grow your own transplant organ'

[Guest guest]

BBC

Thursday, 18 December, 2003, 00:01 GMT

'Grow your own transplant organ'

'Chimaera' pigs were created

Scientists suggest it might one day be possible to grow an animal designed

to provide replacement organs for individual patients.

Injecting bone marrow cells into a sheep foetus produces a " chimaera " - with

a blend of human and sheep cells.

US researchers say that, for example, human liver cells could be harvested

later to boost a failing organ.

Whole organs taken from these animals might be less likely to be rejected by

the body, New Scientist reports.

There is an urgent need for transplant organs, and organs from animals are

one potential source.

Ruled out

So far, this has been ruled out, mainly because of safety concerns about

animal viruses which might have unknown harmful effects in humans if

transferred along with the transplant organ.

Researchers also have to overcome the problem of rejection - the immune

system is likely to attack the new organ, meaning that patients would need

to spend a lifetime on powerful anti-rejection drugs.

At the University of Nevada in Reno, scientists believe they have found a

way to at least partly overcome the rejection issue.

Their idea is to take " stem cells " found in the bone marrow of the human

patient and inject it into an animal foetus growing inside the womb.

The idea is that these human cells would be incorporated into the growing

foetus, forming part of virtually every tissue, and be present in greater

numbers once the animal was fully grown.

No rejection

As these are human cells, there would be no problem with rejection.

The Nevada team, led by Dr Esmail Zanjani, produced sheep human chimaeras

with a high proportion of human cells in some organs.

In some cases between 7% and 15% of all the cells in the sheep's livers are

human.

In the liver, for example, the team believes that it might be possible to

extract clusters of human cells and use them in transplantation operations.

Their sheep human hybrids also contain high proportions of human heart

cells.

The sheep appear biologically normal from the outside, despite their cell

make-up internally.

Even organs which are not exclusively composed might be suitable for

transplantation - and produce fewer problems with rejection.

Dr Alan Flake, from the Children's Hospital in Philadelphia, told New

Scientist that the technique could work.

He said: " I don't think that in 10 to 15 years that's out of the question. "

[Guest guest]

BBC

Thursday, 18 December, 2003, 00:01 GMT

'Grow your own transplant organ'

'Chimaera' pigs were created

Scientists suggest it might one day be possible to grow an animal designed

to provide replacement organs for individual patients.

Injecting bone marrow cells into a sheep foetus produces a " chimaera " - with

a blend of human and sheep cells.

US researchers say that, for example, human liver cells could be harvested

later to boost a failing organ.

Whole organs taken from these animals might be less likely to be rejected by

the body, New Scientist reports.

There is an urgent need for transplant organs, and organs from animals are

one potential source.

Ruled out

So far, this has been ruled out, mainly because of safety concerns about

animal viruses which might have unknown harmful effects in humans if

transferred along with the transplant organ.

Researchers also have to overcome the problem of rejection - the immune

system is likely to attack the new organ, meaning that patients would need

to spend a lifetime on powerful anti-rejection drugs.

At the University of Nevada in Reno, scientists believe they have found a

way to at least partly overcome the rejection issue.

Their idea is to take " stem cells " found in the bone marrow of the human

patient and inject it into an animal foetus growing inside the womb.

The idea is that these human cells would be incorporated into the growing

foetus, forming part of virtually every tissue, and be present in greater

numbers once the animal was fully grown.

No rejection

As these are human cells, there would be no problem with rejection.

The Nevada team, led by Dr Esmail Zanjani, produced sheep human chimaeras

with a high proportion of human cells in some organs.

In some cases between 7% and 15% of all the cells in the sheep's livers are

human.

In the liver, for example, the team believes that it might be possible to

extract clusters of human cells and use them in transplantation operations.

Their sheep human hybrids also contain high proportions of human heart

cells.

The sheep appear biologically normal from the outside, despite their cell

make-up internally.

Even organs which are not exclusively composed might be suitable for

transplantation - and produce fewer problems with rejection.

Dr Alan Flake, from the Children's Hospital in Philadelphia, told New

Scientist that the technique could work.

He said: " I don't think that in 10 to 15 years that's out of the question. "