Scientists are a step closer to creating an anti-ageing drug, after they discovered a key anti-ageing enzyme that stops our cells from decaying. It has long been known that reducing calorie intake can dramatically slow the process of ageing and improve health in later life. Now researchers from the University of Wisconsin-Madison have identified a key enzyme called Sirt3, which causes this dramatic effect in cell molecules. Lead scientist Professor Tomas Prolla said: 'We're getting closer and closer to a good understanding of how caloric restriction works. 'This study is the first direct proof for a mechanism underlying the anti-aging effects we observe under caloric restriction.' The finding not only helps explain the cascade of events that contributes to ageing, but also provides a basis for devising drugs that could extend the average life span. The team studied mice with age-related hearing loss, which is linked to free radical damage to the cells in the inner ear. They focused on the mitochondria - structures inside cells that produce energy and are the sources of highly reactive forms of oxygen known as free radicals, which damage cells and promote the effects of aging. The researchers found under reduced-calorie conditions, levels of Sirt3 increased altering metabolism and resulting in fewer free radicals produced by mitochondria. Signs of free radical damage are skin that is leathery, or wrinkled and sagging, and stiffness in the joints. Smoking, sunbathing, fried food, infections and stress can all produce excess free radicals. However, green leafy vegetables and whole grain bread contain antioxidants that can neutralise them. Professor Prolla said: 'This is the strongest and most direct link that caloric restriction acts through mitochondria.' Sirt3 is one of seven enzymes in the sirtuin family that appear to have a wide-ranging impact on cell fate and physiology. However, the new study published in the journal Cell, provides 'the first clear evidence that sirtuins have anti-aging effects in mammals.' Understanding the molecular basis of how the sirtuin enzymes work may ultimately lead to the development of drugs that activate the pathways of enzymes like Sirt3 to slow down the process of ageing. (The Daily Mail)