19th April 2014

Cloning of human stem cells from adults is achieved

After years of failed attempts, researchers have successfully cloned human stem cells from adult cells – a breakthrough that could one day lead to diseased or damaged cells being regenerated in patients.

A report in the journal Cell Stem Cell describes how the same cloning technique that produced Dolly the sheep was applied, but with adult human cells. Last year, a team at Oregon Health & Science University used this method to clone stem cells from fetuses. This time, the cells were derived from adults – 35 and 75 years old, respectively.

Nuclear transfer, as the process is called, involves taking a donor's DNA – in this case from skin cells – then inserting that DNA into an "empty" egg cell with its DNA stripped out. The resulting hybrid cell is stimulated to fuse and begin dividing, with a new line of stem cells being created within a few days from the donor DNA. These stem cells are then extracted in the laboratory, where further treatments enable them to develop into specific types of cells, like neurons, muscle, insulin-producing cells, or whatever is required. Type 1 diabetics, for example, unable to make enough insulin, could in theory generate their own cells that produced the hormone.

Key to the success of this latest breakthrough was the use of caffeine to prevent the hybrid egg from dividing prematurely. The eggs were made to rest for about two hours – rather than 30 minutes – giving the DNA extra time to adjust and interact with its new environment. This delayed reaction apparently "erased" the cell's history, causing it to behave like an entirely new structure.

Of the 77 samples, however, only two fully developed into clone stem cells. The process remains highly inefficient and expensive, meaning that only extremely rich individuals could benefit at present. Despite this, lead researcher Dr. Robert Lanza and his team at biotech firm Advanced Cell Technology are optimistic that progress will continue. Their experiments have now proved, for the first time, that successful cloning of human stem cells is possible with donors of any age – even the elderly. Lanza now hopes to create a virtual library of cells, using carefully selected DNA donors taken from millions of different samples.

This breakthrough also reignites the debate on full human cloning, its ethical implications and potential for abuse. Marcy Darnovsky, a director at the Center for Genetics and Society, has commented: "If we're going to be having cloned embryos in laboratories around the country, we really need to get our act together and have a law that prohibits human reproductive cloning. Sixty countries have done that."

As to the question of when human cloning might happen – Dr. Paul Knoepfler, from UC Davis School of Medicine, says: "I don't believe that's coming anytime soon, but certainly this kind of technology could be abused by some kind of rogue scientist."

Comments »