Last year, scientists from Japan and the United States revolutionized stem-cell research by demonstrating that they could revert adult cells to an embryonic state just by expressing a few genes. The findings provide a source of cells that, like embryonic stem cells, can theoretically be transformed into any type of cell, and thus could be useful in cell replacement therapies, as for Parkinson's or diabetes. The new cells come without the technical and ethical hurdles of embryonic stem cells and could therefore drastically speed research in this area.

One drawback to the research, however, is that scientists had to genetically alter the cells. While that's fine for research purposes, it limits the cells' potential use in humans. Now scientists report that they can use drugs rather than genes to revert adult skin cells to their embryonic state.

According to a report in the Telegraph,

"This shows that we can make cell reprogramming technology much more practical than it has been," says Dr. [Sheng] Ding, an associate professor at Scripps Research and a chemist who studies stem cell biology. "These advances will bring us closer to the day when we can use these powerful cells to make any kind of human tissue that we need to help patients."

[While previous research] used four genes, at least two linked with cancer, to turn back the clock so they became more embryo like, Dr. Ding uses just two genes, along with drugs, reducing the need for viruses and doing away with the cancer gene.

Dr. Ding believes that, someday, chemical cocktails might be used instead of viruses to reprogram cells for cell-based therapy. One cocktail of small molecules would be used to revert specialized adult cells back to an earlier developmental stage, and then a second cocktail would differentiate the cell into the type needed to replace diseased cells in any organ or tissue.

"This study is a proof of principle that this kind of approach is possible," he says.

While opponents of embryonic stem-cell research say that advances in reprogramming mean that the research should be halted altogether, most scientists working in the field say that both approaches should continue because it's still not clear how closely reprogrammed cells mimic embryonic stem cells.