April 23, 2024

Stem cell breakthrough: safe and ethical

Canadian and British researchers find new method
A Canadian and British team may have made the breakthrough of the year: risk-free pluripotent stem cells created without destroying embryos. "Combining this work with that of other scientists working on stem cell differentiation, there is hope that the promise of regenerative medicine could soon be met," said Sir Ian Wilmut, the stem cell scientist who cloned Dolly the sheep.

When Shinya Yamanaka announced that he created the first so-called induced pluripotent stem cells (iPS cells) from human skin cell back in November 2007, biologists were electrified by the prospect of cures without the ethical baggage. However, the Japanese scientist used a virus to introduce 4 key genes which reprogrammed the cell. This virus could very easily cause tumours to form. At the time Yamanaka predicted that eventually a way would be found to reprogram without viruses. Successive papers had pared down the number of virus vectors from 4 to 1. And now to none.

In two papers in the journal Nature, Keisuke Kaji in Edinburgh and Andras Nagy in Toronto, have described how they reprogrammed cells with a safer technique called electroporation. This ferried genes into the cells through pores. Once the genes had done their job, the scientists removed them, leaving the cells healthy and intact.

The iPS cells have the immense advantage, too, that they are genetically identical to a patient and therefore should not trigger an immune response. The potential for regenerative medicine, drug screening and the establishment of disease models is immense.

Even Alan Trounson, the head of the US$3 billion California Institute for Regenerative Medicine, which was established to do research on human embryonic stem cells (hESC cells), offered his congratulations: "This is a significant contribution. It’s a very innovative way of delivering the gene products that are needed for reprogramming adult cells into embryonic stem cell-like cells."

Despite the advance, there were no calls from scientists to halt work on human embryonic stem cells. In fact, Rick Weiss, of the Democrat thinktank, the Center for American Progress, insisted that it would be foolish to abandon hESC work for a "a new and unproven alternative". He pointed out that the experiment used foetal skin tissue, which would be easier to reprogram.

This advance will also accelerate research into iPS cells’ potential. Because viruses are no longer needed as vectors to introduce genes into a cell, there is no need for a laboratory to have expertise in viruses. It opens the field to even more scientists, according to Dr Nagy. ~ Washington Post, Mar 2; Guardian, Mar 1