Working kidneys made from cloned cow embryo cells

Thousands of transplant patients could benefit from a scientific breakthrough in the use of cloned animal cells to grow artificial organs.

Thousands of transplant patients could benefit from a scientific breakthrough in the use of cloned animal cells to grow artificial organs.

American scientists have successfully created working kidneys from cells taken from cloned cow embryos, marking a leap forward towards the manufacture of spare-part organs from human stem cells.

One of the main obstacles to developing cloned transplant organs has been the problem of rejection by the cloned cell donor. But the results of research published today in the journal Nature Biotechnology demonstrates that, in principle, it is possible to use therapeutic cloning to make organs for transplantation which would not be rejected.

As well as functioning kidneys, the scientists, from the same US biotechnology company that hit the headlines last December by announcing that it had cloned a human embryo, also produced heart and skeletal muscle patches which passed the immunity test.

Between 1995 and 1999, 1,000 patients died waiting for a heart, heart and lung, lung or liver transplant. Around five million Britons are registered potential organ donors, but only one in three suitable patients who die in hospital become donors.

The project was led by Dr Robert Lanza, vice-president of medical and scientific development at Advanced Cell Technology Massachusetts. He said: "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. 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."

Dr Robin Lovell-Badge, a member of the Royal Society working group that reported on therapeutic cloning, stressed that it would be unthinkable to create spare body parts from eight-week-old human foetuses. But the research gave a glimpse of what might be possible using stem cells taken from pinhead-sized embryos.

"What they've shown is that ultimately if they were able to get the various cell types from differentiated embryonic stem cells, they could then make things like artificial kidneys," said Dr Lovell-Badge, of the Medical Research Council's National Institute for Medical Research. "From that point of view I suppose it's good news."

However, he thought the US scientists could have answered their main question – whether mitochondrial DNA was likely to cause rejection – without having to engineer muscle tissue and organs. "There would have been easier ways to do it," he said. "They obviously wanted to show off the fact that they can do the tissue engineering."

The researchers took a single skin cell from an adult cow. This was then fused with a donated cow egg, hollowed out so that its DNA – the blueprint for life – was removed. When this was jolted with electricity, it became an embryo rich in so-called stem cells – the body's "mother" cells which have the potential to develop into any body tissues. Because they came from a cloned embryo, the cells were genetically identical to the donor animal, ensuring that any tissue produced from them would not be rejected.

The scientists produced several miniature kidneys, which were transplanted back into the adult animal, where they then produced urine.