A longer-living, healthier mouse that could hold clues to h...( A study by scientists at UCL (Univer...),Health

A study by scientists at UCL (University College London) shows that mice lacking the insulin receptor substrate (IRS)-1 are more resistant to ageing than normal mice. The research adds to a growing body of work showing the importance of insulin signalling pathways as an ageing mechanism in mammals and potentially humans.

The team studied knock-out mice engineered to lack either insulin receptor substrate (IRS)-1 or -2. These proteins are activated by insulin, a hormone that regulates glucose and fat metabolism, informing the bodys cells when the animal is well fed.

The study, published in The FASEB Journal, shows that mice lacking IRS-1 had an average lifespan increase of 20 per cent when compared to normal mice. In female mice lacking IRS-1 this figure was even higher, averaging 30 per cent. While the expected life-span for a mouse is about 25 months, one of the IRS-1deficient mice in this research lived for 38 months 66 per cent longer than a normal mouse.

As well as living longer, the mice without IRS-1 also experienced better health than the normal mice as they aged they had brighter eyes, were more alert and were much healthier overall. In comparison, the mice that lacked IRS-2 were shorter-lived than the normal mice and displayed signs of obesity and type 2 diabetes.

Professor Dominic Withers, who works with the UCL Centre for Research on Ageing and is lead author of the study, said: Our provisional results indicate that mice lacking IRS-1, particularly female mice, are more long-lived and show resistance to a range of markers that indicate ageing including skin, bone, immune, and motor dysfunction.

Whats more, these improvements were seen despite the fact that removing IRS-1 made the mice resistant to insulin throughout their lives. These results suggest that IRS-1 is a pathway conserved by evolution that regulates the lifespan of mammals, and it may point to methods of potentially delaying ageing in h
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