Body, heal thyself

‘The stem‐cell genie is out of the research bottle,’ columnist William Safire wrote on July 16 in the New York Times editorial page, continuing, ‘If we command it sensibly, this unexpected servant will help us lead much healthier, longer lives.’ Safire is not alone in having these expectations. Since research using embryonic stem cells has been dragged into the limelight of public debate, its supporters have never tired of emphasising the potential medical breakthroughs that might slumber in these undifferentiated cells. But will stem cell transplants and therapeutic cloning become the new medicine of the future, and what are the prospects for tapping this spring of eternal youth, the mysterious stem cell? Since the political debate has been shaped mainly by future expectations, it is therefore appropriate and necessary to take stock of where research with embryonic stem cells is right now.A recent symposium organised by the European Molecular Biology Laboratory examined the scientific and technical state of the art in stem cell research and therapeutic cloning. Prominent scientists presented the latest results in a field as beset by ethical problems as it is fast‐moving.Lovell‐Badge, from the National Institute for Medical Research in London, presented a slide of a brown and white mottled mouse, a chimera made by replacing cells in a white mouse 8‐cell embryo with embryonic stem (ES) cells from a brown mouse. The mouse is perfectly healthy: proof that in mice, at least, ES cells are totipotent. And they can be cryopreserved indefinitely: cells such as these have been used for 20 years and still perform, noted Lovell‐Badge. In vitro these cells can be differentiated into cardiac and skeletal muscle, blood vessels, haematopoietic cells, insulin secreting cells and various neural cells.As far back as 1975 scientists with foresight were considering the prospects of using …