Two research teams have identified a gene that plays a pivotal role in both ageing and obesity. David Sinclair, one of the researchers involved, hopes the findings will lead to a 'totally new class of drug that stimulates the body's own defences and combats the diseases of ageing'. Targeting the gene may also lead to treatments for obesity.
It has long been known that a low-calorie diet slows the ageing process. Until now, scientists had not fully understood how this process works, speculating that the reduction in the metabolic rate, which a calorie-controlled diet causes, reduces the number of cells killed by free radicals. The destruction of irreplaceable cells leads to the symptoms of ageing.
One of the new research papers, published in Science magazine, reveals that a low-calorie diet activates the gene SIRT1. As the protein produced by this gene prevents cell death, the researchers suggest activation of SIRT1 as the primary mechanism by which a low-calorie diet slows the ageing process. 'Cumulative effects of cell loss have been implicated in various diseases including neurodegeneration, retinal degeneration, cardiovascular disease and frailty', states the report, produced by a team from Harvard Medical School in Massachusetts, USA.
The other study, carried out by a team from Massachusetts Institute of Technology (MIT), discovered that activation of SIRT1 prevents unspecialised cells from forming fat. The research, published earlier this month in Nature, also found that stimulation of the gene causes fat cells, known as adipocytes, to metabolise the fat they contain. 'Calorie-restricted mice shed their fat, and mice engineered to be lean lived longer. This suggested that SIRT1 could be recognising food scarcity and causing fat shedding', said Leonard Guarente, one of the MIT researchers, who described the results as 'a very important finding'. Guarente is a co-founder of Elixir Pharmaceuticals, which develops therapeutics to combat the diseases of ageing.