Reprogramming stem cell breakthrough

Two groups of scientists have managed to 'reprogramme' skin cells, retuning them to an embryonic-like state in which they regain the potential to develop into any type of body cell. The studies, published in the journals Cell and Science, pave the way for new research aimed at generating genetically-matched cell therapies for a range of debilitating diseases. One of the teams, lead by Dr Shinya Yamanaka at Kyoto University in Japan, used skin cells taken from the face of a 36-year-old woman. The other group, lead by Professor James Thomson at the University of Wisconsin, used immature skin cells taken from a human fetus and the foreskin of a newborn baby boy.

The Japanese team first achieved success in reprogramming adult mouse cells, in a landmark study reported last year. They transformed the cells by ramping up production of four key mouse genes identified as being key to the reprogramming process, called Oct4, Sox2, Klf4 and c-Myc. Now, the team have treated human cells with the human versions of these genes to achieve the same effect. The resulting 'pluripotent' cells are similar - but not identical - to embryonic stem cells (ES cells), and the researchers were able to use them to produce brain and heart tissue. 'These cells should be extremely useful in understanding disease mechanisms and screening safe and effective drugs', said Dr Yamanaka.

The US group used a slightly different cocktail of factors, but they too managed to produce the versatile cells, dubbed 'iPS (induced pluripotent stem) cell. They produced eight new stem cell lines for use in research. Since both techniques rely on the use of viruses to introduce the crucial genes, they are not suitable for clinical applications. An accompanying comment piece in Cell also stresses that the groundbreaking studies do not circumvent the need for further research on human ES cells, saying it would be 'a big mistake' to consider human ES cells obsolete, and that 'many hurdles' need to be overcome before iPS cells can be used therapeutically. It concludes that ES cell research is 'more important than ever', since it will shed light on how iPS cells can be maintained in their flexible state, and how they can be persuaded to grow into different tissues.

Professor Robin Lovell-Badge, of the UK's National Institute for Medical Research, said the work was 'very exciting', but added that 'it doesn't remove the need to do the cloning approach but if it really works as well as it might, it's going to make it a lot easier to make pluripotent, patient-specific stem-cell lines'. He went on to say: 'We always said there was a hope that research would lead to direct reprogramming to avoid the use of embryos. This has just come sooner than any of us thought. This unpredictability is one of the fantastic things about science, and it is the reason that research avenues should always be open'.