The mice in Maria Rupnick's lab eat like pigs. They've always got their snouts in the trough. "If they're awake they're eating, and if they're not eating they must be asleep," says Rupnick, Who works at Brigham and Women's Hospital in Boston. Needless to say, all this scoffing has made them a little tubby - in fact they look like furry baseballs with legs. The mice belong to a strain with a mutation that makes them constantly hungry, and they have been at the front line of medical research into obesity for decades. Despite scientists' best efforts, however, there are still no chemical fixes for the epidemic of obesity sweeping the west. Drugs have been developed to boost metabolism, suppress the appetite, even block fat absorption in the gut - but none is an effective long-term solution. Existing diet drugs usually cause only a small loss in weight, and are not supposed to be taken for longer than a year because question marks hang over their safety for prolonged use. With the help of her congenitally greedy mice, however, Rupnick has hit on a completely new approach to tackling fat. She has found a way to shrink adipose tissue by melting away its blood supply. Her inspiration has come from an apparently unrelated field of medicine - cancer research. One of its hottest topics at the moment is the development of "angiogenesis inhibitors", drugs that block the growth of new blood vessels to supply tumours. Rupnick's work suggests these agents are even more effective at shrinking fat than they are at throttling tumours. It could eventually lead to the development of more effective weight-loss drugs that patients could take safely for years. And in a neat twist, her latest findings point to a way of destabilising the blood vessels that supply tumours, making them just as susceptible to angiogenesis inhibitors as the capillaries feeding fat tissue.
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