Clone tissue transplant success

[Guest guest]

http://news.bbc.co.uk/hi/english/health/newsid_2018000/2018444.stm

Scientists have successfully used cloning technology to grow tissues for

transplant in cows which will not be rejected.

A US team have been able to engineer miniature kidneys and small " patches " of

heart tissue from cloned cells and

successfully test them in cows. They said that the fact that the sophisticated

immune system of the cow did not reject

the tissue provides hope therapeutic cloning could also be carried out on humans

without rejection. But the technique

is unlikely to be used in humans because legislation prevents organs being

removed from mature foetuses.

The research, led by scientists at Advanced Cell Technology (ACT), in Worcester,

Massachusetts, was published in the

journal Nature Biotechnology.

The aim of therapeutic cloning is to take a cell from a patient and grow nerve,

muscles or cartilage to replace their

own tissue. It is hoped it will be possible to create tissue which is a perfect

match for the patient. Scientists hope

it could be used to treat patients who have heart, lung, liver or kidney disease

- and even conditions such as diabetes,

arthritis, Aids, strokes or cancer. The problem in studies so far has been that

animals produced by cloning inherit

some DNA from the egg rather than the donor cell, and these 'foreign genes'

create a risk of rejection after

transplantation.

In the ACT study, cows were cloned and the resulting embryos grown in the cow's

womb. When, after a few weeks, the

organs had begun to form, the researchers removed some kidney and muscle cells

and grew them into mini-organs. These

were then grafted back under the skins of the cows from whom they were cloned.

The scientists found the organs were not

rejected, despite having some foreign DNA, and also began working.

I would be quite surprised if this would be permitted in human embryos in any

state of the US - or anywhere with the

facilities to carry it out. (Baroness O'Neill, House of Lords select committee

on stem cell research)

As a cow's immune system is relatively complex; the researchers say their

success indicates human applications may be

possible. Lanza, vice president of medical and scientific development at

ACT, who led the study, said:

" This study furnishes the first scientific evidence that cloned tissues can be

transplanted back into animals without

being destroyed by the body's immune system. The use in medicine to generate

immune-compatible cells using cloning

would overcome one of the major scientific challenges in transplantation

medicine - namely, the problem of organ and

tissue rejection. These results bode well for the future of human therapeutic

cloning. Cloning could theoretically

provide a limitless supply of cells and organs for any type of regenerative

therapy. Before now, therapeutic cloning as

a means of preventing rejection was criticised by some as being purely

theoretical - just an idea. "

The researchers used cloned bovine foetuses to generate the necessary cells, but

say in humans, technology should only

be used to clone human embryonic stem cells and not an actual pregnancy. The

method used in their research could not be

used in the UK because legislation forbids the removal of organs from a human

embryos more than 14 days old. Baroness

O'Neill, a member of the House of Lords select committee on stem cell research,

said:

" This is when the 'primitive streak' can first be seen in the embryo - up to

that point the embryo may split and become

twins. It is when the embryo starts becoming an individual. I would be quite

surprised if this would be permitted in

human embryos in any state of the US - or anywhere with the facilities to carry

it out. "

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Good health & long life,

Greg ,

http://optimalhealth.cia.com.au