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[h1]Cloning of human organs a step closer
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By Nick Collins, The Daily TelegraphOctober 5, 2011
The cloning of human organs has moved a step closer after scientists in New York used a controversial technique to create embryonic stem cells in the lab for the first time.
Researchers took DNA from an adult skin cell and injected it into a human egg, producing an early-stage embryo before extracting stem cells.
Test tube embryos have been made before but the latest experiment, using a similar method to the one that produced Dolly the sheep, is thought to be the most successful yet.
The cells produced could not be safely transplanted into humans, however, because they developed with too many chromosomes.
Previous attempts to create early-stage embryos using the technique have stalled because the cells stopped multiplying.
This time they developed far enough to enable researchers to extract stem cells, which can multiply and turn themselves into any other cell type. If researchers can perfect the technique it could lead to a new generation of medical treatments because doctors could grow healthy cells to replace diseased tissue using a patient's own DNA, cutting the risk of them being rejected by the body.
The subject is highly controversial because there are concerns that it could lead to attempts by maverick doctors to produce cloned babies, in breach of ethical regulations. Hwang Woo-suk, a South Korean scientist, has claimed to have generated stem cells from cloned human embryos, but his evidence was later found to be bogus.
Dr Dieter Egli, one of the authors of the research team's report, which was published in the journal Nature, said there was a "great question mark" over whether the technique could be developed enough to be used safely in humans.
The method, known as somatic cell nuclear transfer, involves taking the nucleus of a human skin cell and transferring it into an egg cell to create an embryo.
In animals such as sheep, researchers remove the egg DNA before replacing it with the nucleus of the animal cell, but in humans this stops the egg from developing into more than six to 12 cells. Researchers led by Dr Scott Noggle, of the New York Stem Cell Foundation Laboratory, found that if they left the egg cell's DNA intact and added the skin cell nucleus, the early embryo continued developing to a stage where stem cells were produced.
These were then removed and cultivated to produce several different types of cell.
The downside of the method is it means the resulting cells have three chromosomes rather than two, which could lead to serious health complications.
Embryos which have the wrong number of chromosomes often fail to develop, while having three versions of a particular chromosome causes Down's syndrome.
But the researchers in New York hope that they will be able to find a way of refining the technique to generate stem cells containing only DNA from the donor cell.
Prof Mary Herbert, from the Institute for Aging and Health at Newcastle University, said: "This study shows that the conventional approach to somatic cell nuclear transfer is inefficient in humans.
"However, the authors were able to increase the efficiency by leaving the host oocyte [egg] genome in place.
"While this approach does not in itself provide a solution, it takes us a step closer to understanding where the problems lie."
First thing that came to mind was using this technology to replace cancerous organs with new ones... Think of the possibilities..
But then again, this DOES go against human ethics. What is NT's take on this?
