SUSPENDED animation is poised to move from science fiction to reality: scientists have successfully induced a state of reversible hibernation in mammals for the first time, using methods that could eventually be applied to human beings. The breakthrough in the United States promises to allow doctors to slow human metabolism almost to a standstill, protecting critically ill patients from damage to the brain and other organs that would normally be inflicted by oxygen deprivation. Patient trials could begin within five years.The "hibernation on demand" technique, which has been pioneered in mice, also raises the prospect of putting astronauts to sleep for long voyages in space — a staple of science fiction films such as Alien and 2001: A Space Odyssey. In a study at Fred Hutchinson Cancer Research Centre in Seattle, a team led by Mark Roth used hydrogen sulphide gas to place mice into artificial hibernation, slowing their cellular activity virtually to a standstill. The animals were left in this state for up to six hours before being revived without any lasting ill effects. As hibernation drastically reduces the amount of oxygen that cells need to survive, such suspended animation would have significant medical benefits if it could be induced among human patients. It could be used to buy time when treating severe blood loss, hypothermia, fevers, heart attacks and strokes, in which oxygen deprivation kills off tissue, leading to disability or death. Dr Roth said that there was no technical reason why the same procedure would not work in humans. "We think this may be a latent ability that all mammals have — potentially humans — and we're just harnessing it and turning it on and off, inducing a state of hibernation on demand," he said.
The research, published today in the journal Science, could improve cancer therapy. Cancer cells do not require oxygen to grow and this makes them less vulnerable to radiation than healthy cells. Radiotherapy generally kills more ordinary cells than cancerous ones. Slowing down cell metabolism before treatment could allow increased radiation to knock out tumours better.While the notion of placing a human into hibernation appears far-fetched, there have been dozens of cases in which people have survived prolonged periods of low metabolism, usually brought on by extreme cold.