The following comes from a Sept. 11 story on the BBC News.

The living tissue inside an animal has been regressed back into an embryonic state for the first time, Spanish researchers say.

They believe it could lead to new ways of repairing the body, for example after a heart attack.

However, the study published in the journal Nature, showed the technique led to tumours forming in mice.

Stem cell experts said it was a “cool” study, but would need to be much more controlled before leading to therapies.

When an egg is first fertilised, it has the potential to develop into every tissue in the human body, from brain cells to skin.

That flexibility is lost as an embryo develops. However, transforming adult tissues back into an embryonic-like state may lead to treatments that can regenerate a weakened heart, or the light-sensing cells in the eye or even the brain after a stroke.

The transformation has been done in a laboratory, by treating skin samples with a mix of chemicals or genetic modification.

Now scientists at the Spanish National Cancer Research Centre in Madrid have achieved the same results inside an animal.

“It is a surprising result, this was not expected, most of us thought that it would be impossible,” lead researcher Prof Manuel Serrano told the BBC.

The research group used mice genetically modified to switch on, when they were given a specific drug, production of four chemicals shown to reverse a tissue’s destiny in the laboratory.

Tissues were successfully transformed back into an embryonic state, but without further direction they rapidly developed into tumours.

Speaking on Science In Action on the BBC World Service, Prof Serrano said: “Of course this is not what we want for regenerative medicine.

“We want to turn back the clock in a controlled manner and this is something we have to work out in the future.

“We have to find conditions where we reprogramme only partially so that they acquire a plastic state and repair the tissue.”

To read entire report, click here.