The successful transformation of skin cells into stem cells announced this week by research teams in Japan and the US is an achievement of considerable importance. Yet many will struggle to understand the deep significance of this discovery. The science involved is not easy to grasp, and yet this discovery has opened up enormous potential for powerful new medical treatments for conditions as varied as diabetes, heart attack and Parkinson's disease. We may not understand the concepts involved, but we will all share in the benefits likely to flow from this research in the coming years.
Stem cells are a form of starter cell that can grow into any of the body's 220 or so different tissue types, a versatility allowing them to be described as "pluripotent". They first arise in the emerging embryo several days after the fusing of sperm and egg, and are used to fashion the growing foetus. They change in a tightly controlled pattern to become nerves, muscle, bone and heart. Stem cells were first coaxed from a growing human embryo in 1998, and herein lies one of the great impediments that has slowed the advance of this powerful technology.
The harvesting of stem cells invariably leads to the destruction of the embryo, raising ethical challenges that have yet to be resolved a decade on. Some argued that destroying the embryo was justified if it could cure disease. Others countered that killing potential human life - even if sourced as "leftover" embryos from fertility clinics - was wrong and could never be justified.
Scientists attempted to get round these challenges by finding ways to create "artificial" embryos not derived from a fertilised egg. Last week there was an important breakthrough in this field describing how a monkey skin cell had been fused with an egg to create an embryo that yielded stem cells. This work has now been overtaken by the new technique which at no stage requires an embryo, whether naturally or artificially derived.
In a single stroke this lifts the heavy ethical burden from stem cell research. The researchers took ordinary skin cells and used a virus to carry four key genes into the cell. This DNA causes the cell to "forget" it was a skin cell and reprogrammes it to become a stem cell. The battery of tests conducted so far indicates that these new stem cells are indistinguishable from the pluripotent stem cells extracted from embryos. They have also been coaxed to transform into other cell types including brain, heart, fat, cartilage and muscle. The work opens the way for personalised treatments with no risk of tissue rejection, given the recipient would also be the donor, affording a perfect genetic match. The discovery is also important in giving Irish researchers an opportunity to delve into the most complex levels of stem cell research.
The scientists involved warn there should be no quick cures expected from the findings. It will take some years to prove the cells are safe, something that also encourages them to call for continued research into embryonic stem cells despite the ethical complexities.