Scientists have used cloning technology to create fully functioning kidneys in the laboratory.
They hope the breakthrough could one day help to solve the problem of a severe shortage of donor organs for transplant.

The organs were created from cells taken from a cow's ear.

They were genetically identical to the donor cells and so could be transplanted back into the animal without risk of rejection.

The work has been carried out by Advanced Cell Technology in Massachusetts, the private firm that stirred up controversy last year when it announced the creation of the "world's first human embryo clones".

Organ shortage

It is estimated that 100,000 people in the UK suffer from some form of severe kidney disease.

The NHS carries out approximately 1,200 kidney transplants a year, but almost 6,000 patients are waiting for a new organ at any one time. Many die before a suitable organ becomes available.

The ACT team took a single skin cell from the ear of an adult cow. This was fused with a donated cow egg which had been stripped of its own genetic material.

The scientists then used a jolt of electricity to stimulate the fused cell to become an embryo.

The embryo was rich in stem cells that have the potential to become a wide range of body tissues.

Secret treatment

Some of these stem cells were then subjected to secret chemical treatments to turn them into fully mature kidney cells.

They were nurtured on a biodegradable kidney-shaped scaffold designed by a team from Harvard Medical School.
The scientists produced several miniature kidneys each a couple of inches long. These were transplanted back into the adult animal, alongside its existing organs, where they started to produce urine.

The UK's National Kidney Research Fund issued a statement saying it was "very encouraged" that scientists were looking for ways to overcome the organ shortage problem.

But it went on to say: "Once the kidneys have failed, a patient needs lifelong treatment via a kidney transplant or dialysis in order to survive and transplantation is the most effective treatment for patients with end-stage renal failure and the only treatment available for end-stage liver or cardiac failure.

"The Fund believes, however, that the prospect of growing full size organs that perform all the functions of the native kidneys by cloning technology, like the prospect of an abundant source of animal organs for humans with failure of the kidneys, is a little closer but still a long way off."