Mice with sky-high metabolic rates live far longer than their sluggish cousins, UK researchers have found, raising the prospect that human lifespan might be lengthened with metabolism-boosting drugs.
More efficient cells
The secret to longevity may lie inside mitochondria, the powerhouses of the cell that help to set the metabolic rate. Mitochondria use oxygen to 'burn' food molecules to produce chemical fuel that is used by the cell — but in the process they generate harmful free radicals that damage other molecules and are linked to ageing.
Speakman's team found evidence that mice with a high metabolic rate have more vigorous 'uncoupling proteins', which cause the mitochondria to generate heat instead of producing fuel. Since more of their energy escapes as heat, the mitochondria have to run at full speed in order to keep generating enough chemical fuel for the cell.
At the same time, the mitochondria may run more efficiently and release fewer harmful free radicals, hence slowing the ageing process. "That's when they run the cleanest," explains Wayne Van Voorhies, who studies ageing at New Mexico State University, Las Cruces.
Speakman now plans to test if a higher metabolic rate can prolong human life, but he cautions that a quick fix to ageing is unlikely to be just around the corner. Although drugs such as amphetamines are known to speed up metabolism, Speakman says that they may not simultaneously increase the activity of uncoupling proteins, the key to cutting free-radical production and thus potentially prolonging life.
Indeed, finding drugs that really do boost uncoupling proteins may be difficult, warns Van Voorhies. "You're really messing with some fundamental characteristics of [the cell]," he says.
- Live fast, die old @ nature.com