From Nature:
By 2050, the number of people over the age of 80 will triple globally. These demographics could come at great cost to individuals and economies. Two groups describe how research in animals and humans should be refocused to find ways to delay the onset of frailty.
The problems of old age come as a package. More than 70% of people over 65 have two or more chronic conditions such as arthritis, diabetes, cancer, heart disease and stroke1. Studies of diet, genes and drugs indicate that delaying one age-related disease probably staves off others. At least a dozen molecular pathways seem to set the pace of physiological ageing. Researchers have tweaked these pathways to give rodents long and healthy lives. Restricting calorie intake in mice or introducing mutations in nutrient-sensing pathways can extend lifespans2 by as much as 50%. And these 'Methuselah mice' are more likely than controls to die without any apparent diseases3. Post-mortems reveal that tumours, heart problems, neurodegeneration and metabolic disease are generally reduced or delayed in long-lived mice. In other words, extending lifespan also seems to increase 'healthspan', the time lived without chronic age-related conditions.
These insights have made hardly a dent in human medicine. Biomedicine takes on conditions one at a time — Alzheimer's disease, say, or heart failure. Rather, it should learn to stall incremental cellular damage and changes that eventually yield several infirmities. The current tools for extending healthy life — better diets and regular exercise — are effective. But there is room for improvement, especially in personalizing treatments. Molecular insights from animals should be tested in humans to identify interventions to delay ageing and associated conditions. Together, preclinical and clinical researchers must develop meaningful endpoints for human trials.
Picture: Fauja Singh, here aged 100, prepares for Britain's Edinburgh marathon in 2011
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