Researchers in Madrid have successfully reprogrammed adult cells in living animals, creating stem cells that have the ability to grow into any tissue found in the body. Until now, these stem cells – known as pluripotent stem cells – have only ever been created in a lab after being removed from the animal. However, researchers at the National Cancer Research Centre in Madrid were able to create them in the bodies of living mice. They found that they could reprogram adult cells from the mice using a cocktail of so-called “reprogramming factors”.
“It’s something we never expected, it was a surprise and it opens up the chance to create more efficient cells than those generated in vitro,” says head team researcher Manuel Serrano.
Cells in the rodents’ kidney, stomach, intestine and pancreas all showed signs of being reprogrammed back to an extremely versatile and powerful state, like embryonic stem cells. The technique confirms that reprogramming can be done in living tissue and not just in the lab dish.
“In multiple tissues and in many places the cells lose their identity. For example liver cells are no longer liver cells, the same goes for bowel cells etc… they become embryonic stem cells,” said Dr Serrano.
The technique overcomes the difficulties inherent in making cells outside the body, grafting them into people, and then of potential rejection. It opens up a whole world of new clinical opportunities, according to the researchers.
However, therapeutic applications, such as repairing damaged spinal cord or creating new insulin-producing cells, are still distant. Clinical trials on humans are unlikely to start before 2018, according to Dr Serrano.
The researchers in Madrid were inspired by a technique invented by Nobel prize-winner Shinya Yamanaka. His team created embryonic stem cells of a new type by reprogramming adult cells in a lab dish with a combination of four genes. This procedure turned their clock back to an immature stage where they could become any sort of specialist cell. This was done in a lab, however, not in a living animal.
The researchers in Madrid did something quite different: they bred genetically engineered mice with the same cocktail of four reprogramming genes – and switched them on by adding a particular drug to the animals’ drinking water. After a few weeks, embryonic stem cells appeared in multiple tissues and organs. The researchers extracted these cells and demonstrated through various tests that they were similar to those in a new embryo. Embryonic cells made in so-called “reprogrammable mice” also survive in culture dishes outside the animals.
“Being able to manipulate them in the laboratory will allow us to get to know them better and find out how far they can develop,” said researcher Maria Abad.
The next step is to find out whether these new stem cells can efficiently generate different kinds of tissue such as pancreas, liver or kidney tissue.
It may all sound like science fiction. And so far, it is. But sci-fi could soon become reality. The first trial of stem cells produced from a patient’s own body has been approved by the Japanese government. Researchers will use the cells to attempt to treat a form of age-related blindness. And the Spanish discovery plays a crucial role in developing this new kind of therapy.