Researchers in the UK and Canada have successfully created induced pluripotent stem (iPS) cells suitable for potential future use in humans.
iPS cells are adult cells (in this case skin cells) that have been reprogrammed into a pluripotent embryonic-like state, able to divide into any cell in the human body. Opponents of embryonic stem (ES) cell research claim iPS cells present the best alternative as they appear to hold the same therapeutic potential without destroying embryos in the process. Further, as iPS cells would be created from skin cells taken from the recipient, the risk of rejection would be eliminated.
The cells were first created in 2007 by two independent teams of scientists in Japan and in the US using viruses to carry extra genes which would modify the skin cells. However, due to the risk of the viruses triggering cancer cells, this method made the resulting iPS cells unsafe for human use, limiting their therapeutic value. Now, however, the two teams from the University of Toronto and the Medical Research Council Centre for Regenerative Medicine at the University of Edinburgh, have overcome this problem using a technique called electroporation, allowing them to insert the genes through pores rather than using viruses. The genes were later removed making the cells entirely free of foreign DNA.
'I was very excited when I found stem cell-like cells in my culture dishes. Nobody, including me, thought it was really possible,' said Dr Keisuke Kaji, who led the study at the University of Edinburgh, adding: 'It is a step towards the practical use of reprogrammed cells in medicine...' However, he added that the efficiency of the process would need to be improved. From Toronto, Professor Andras Nagy who co-authored the paper said: 'We hope that these stem cells will form the basis for treatment for many diseases and conditions that are currently considered incurable. We have found a highly efficient and safe way to create new cells for the human body which avoids the challenge of immune rejection.'
Commentators both for and against ES cell research welcomed the news. Professor Sir Ian Wilmut, who led the team that cloned Dolly the Sheep, said the findings were a 'significant step in the right direction,' and Josephine Quintavalle of Comment on Reproductive Ethics (Core), said it is 'ethical stem cell research at its best.'
Meanwhile in the US, a group of scientists at the University of California Los Angeles became the first to engineer iPS cells into functioning motor neurons. Writing in the journal Stem Cells, the team, led by William Lowry, said that the 'findings support the possibility that reprogrammed somatic cells might prove to be a viable alternative to embryo-derived cells in regenerative medicine.' The next step will be to try to generate a response when attaching the neurons to muscle cells.
In related developments, US Senators Tom Harkin and Arlen Specter have introduced a bi-partisan bill in support of federal funding for ES cell research into the US Senate. The bill is identical to that vetoed by President Bush in 2007.