Scientists have finally made the long-awaited breakthrough in human cloning by turning skin cells into early-stage embryos that were then used to create specialised tissue cells for transplant operations, it has been revealed today.
Those cells can turn into any cell of the body, so scientists are interested in using them to create tissue for treating disease. Transplanting brain tissue might treat Parkinson’s disorder, for example, and pancreatic tissue might be used for diabetes.
But transplants run the risk of rejection, so more than a decade ago, researchers proposed a way around that: Create tissue from stem cells that bear the patient’s own DNA, obtained with a process called therapeutic cloning.
Experts claimed the work raised the prospect of “therapeutic cloning” in which patients’ own skin could be used to grow replacement cells for parts of their body damaged by illness or injury.
In Wednesday’s edition of the journal Cell, however, scientists in Oregon report harvesting stem cells from six embryos created from donated eggs. Two embryos had been given DNA from skin cells of a child with a genetic disorder, and the others had DNA from fetal skin cells.
Dr Shoukhrat Mitalipov, who led the study, insisted that his work was focused on creating stem cells for use in medical treatments and said the findings were unlikely to lead to any attempt at human cloning by other researchers, writes the Telegraph.
The technique involves removing the nucleus of a skin cell, which contains a patient’s DNA, and implanting it into an egg cell which has had its original nucleus removed.
The unfertilised egg cell then begins to develop into an embryo and produce stem cells. Because they contain the patient’s genetic code, the cells could be transplanted into the patient’s body without the risk of rejection by their immune system.
Mitalipov also said that based on monkey work, he believes human embryos made with the technique could not develop into cloned babies, and he has no interest in trying to do that. Scientists have cloned more than a dozen kinds of mammals, starting with Dolly the sheep.
Dr Mitalipov made important technical advances that enabled the cloned human embryos to survive to the 150-cell stage, known as a blastocyst, when embryonic stem cells can be extracted for growing in the laboratory into specialised tissue cells, such as nerve cells or cardiac muscle.
He said: “Our finding offers new ways of generating stem cells for patients with dysfunctional or damaged tissues and organs.
“While there is much work to be done in developing safe and effective stem cell treatments, we believe this is a significant step forward in developing the cells that could be used in regenerative medicine”.
However, the breakthrough will also raise serious ethical concerns about the creation of human embryos for medical purposes and the possible use of the same technique to produce IVF embryos for couples wanting their own cloned babies – which is currently illegal in the UK, reports the Independent.
Boston Cardinal Sean O’Malley, point man for the U.S. Catholic bishops on bioethical issues, said Wednesday (May 15) that “this means of making embryos for research will be taken up by those who want to produce cloned children as’copies’ of other people.”
Human cloning “treats human beings as products,” O’Malley said on behalf of the bishops, “manufactured to order to suit other people’s wishes. … A technical advance in human cloning is not progress for humanity but its opposite.”