Stem Cell Breakthrough Now Moves A Step Ahead!

Pioneering work by Japanese stem-cell researchers two years ago has taken a major step forward, helping the quest for versatile, grow-in-a-dish transplant tissue, according to papers published on Sunday.

Two teams have combined ideas to devise a safer technique for reprogramming skin cells so that they become "pluripotent" stem cells, fundamental cells that then grow into specialised organs.

Their effort builds on an award-winning breakthrough in 2007 by Shinya Yamanaka of Kyoto University.

He and his team introduced four genes into skin cells, reprogramming them so that they became indistinguishable from embryonic stem cells.

That achievement conjured the distant vision of an almost limitless source of transplant material that would be free of controversy, as it would entail no cells derived from embryos.

But the downside of the technique for creating these so-called induced pluripotent stem cells (iPS) is that the genes are delivered by a "Trojan horse" virus.

Reprogramming cells using a virus modifies their DNA in such a way that they cannot be given to patients without boosting the risk of cancer.

In the new studies, published by the British-based journal Nature, two squads of researchers from Britain and Canada recount a method by which the four genes are delivered into the cell without using a virus, and then are removed after the reprogramming is done.

The insertion is carried out using "piggyBac," a tried-and-tested technique in genetically-modified crops in which mobile genetic sequences called transposons are slotted into the genome.