The results of a study conducted by researchers at the Massachusetts General Hospital and Harvard Medical School in Boston mark another step forward toward fulfilling the technique developed during the last two years, that gives stem cells produced from adult cells the same force as those created using human embryos, by developing a safer way of obtaining stem cells from common skin cells without using harmful viruses that can cause cancer.

For the study, which is published in the Sept. 25 online edition of the journal Science, scientists used a much more harmless virus, called an adenovirus, to carry into the cells the four transformative genes, called Oct4, Sox2, Klf4 and c-Myc. To get the genes into the cells, scientists have had to use retroviruses, which involved inserting their viral DNA into a cell’s chromosome. Retroviruses can integrate into the genome and pose a risk of cancer. “The adenovirus doesn't integrate permanently, so the cells aren't altered genetically,” said Konrad Hochedlinger, geneticist at Harvard Stem Cell Institute in Cambridge, Mass., and lead author of the paper.

If the new method can be applied to human cells, it may offer a safe way to test cell therapy to treat Parkinson’s or other degenerative diseases.

The technique which uses skin cells, reprogramming them into embryonic-like stem cells is easier and it has fewer moral restrictions and problems.

Previously, researchers have managed to generate induced pluripotent stem cells (iPS), which are cells that have all the qualities of embryonic stem cells using the technique pioneered by Shinya Yamanaka of Kyoto University in Japan. Yamanaka first demonstrated in 2006 that adult mouse skin cells could be reprogrammed into something similar with embryonic stem cells by the introduction of four specific genes.  Just like the ordinary stem cells, the new induced pluripotent stem cells could be cultured into any desired tissue, from heart muscle cells, and blood cells to brain cells.

Stem cells have the potential to develop into many different cell types in the body, serving as a sort of repair system for the body. They can divide without limit to replace other cells in the body as long as the person or the animal is still alive. Unlike other cells such as muscle cells, blood cells, or nerve cells, the stem cells divide and each new cell may remain a stem cell or become another type of cell with a specialized function.

The cell reprogramming technique took center stage at the 2008 World Stem Cell Summit, which took place at the Alliant Energy Center in Madison, which took place earlier this month. The new technique opens up the possibility of converting, for example, a bit of heart tissue into cardiac muscle cells for people who suffered a heard attack and it is faster. Scientists say the new reprogrammed cells will be most beneficial in improving understanding of the disease and providing targets for drug testing.