Purging old, worn-out cells helps mice live longer, healthier lives, and seems to stave off a multitude of age-related diseases. We might eventually enjoy the same benefits, with the launch today of a company aiming to develop drugs that wipe out these 鈥渟enescent鈥� cells in humans.
When cells wear out, they don鈥檛 always die. Instead, they can start pumping out a brew of compounds that can cause damage to surrounding tissue. The process, called senescence, is thought to protect us against cancer and help wounds heal.
But as we get older, senescent cells start to accumulate across the body, and may be partly responsible for the general wear and tear of all our organs as we age. Elevated numbers of these cells have already been linked to heart failure, arthritis, 础濒锄丑别颈尘别谤鈥檚 鈥� and cancer.
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Get rid of these cells and a host of benefits ensue, suggest mouse studies by , and their colleagues at the Mayo Clinic in Rochester, Minnesota. The team used mice which had had their senescent cells tagged with a 鈥渟uicide gene鈥�. When activated by a specific drug, it triggers the death of about 70 per cent of senescent cells at a time.
The team used this method to wipe out senescent cells from mice that were 12 months old 鈥� about 40 in human years 鈥� twice a week, for the rest of their lives. It is around this age that the accumulation of senescent cells is thought to start causing problems. 鈥淭his can be thought of as a prevention strategy, because we never let the cells accumulate,鈥� says Baker.
Live longer, healthier
The treated mice lived, on average, around 25 per cent longer than their untreated counterparts. 鈥淭hat鈥檚 the equivalent of extending human life from 80 to 100 years,鈥� says Baker.
What鈥檚 more, the treated mice were able to stave off age-related disease. After 6 months of treatment, their hearts were healthier, and they were better at recovering from stress. Their kidneys showed less of the scarring usually seen with ageing. They didn鈥檛 develop cataracts or cancer until much later in life, compared with untreated mice. They even looked younger, because they didn鈥檛 show the same fat loss as untreated mice.
The results echo those of a similar study by Baker and his colleagues in 2011, when they used the . This is the first time an effect has been seen in normally ageing mice.
The race is now on to discover drugs that might be able to clear senescent cells in people. 鈥淚f you had asked me about this in 2011, I would have said we were a long way off,鈥� says Baker. 鈥淏ut we鈥檝e been working with a company to find drugs that kill senescent cells, and it鈥檚 easier than we thought.鈥� The ultimate aim is to develop a drug that could hit all age-related diseases in one go.
To that end Baker is working with Unity Biotechnology, which launches today and bills itself as the first company to develop medicines that specifically target senescence. One of its founders is of the Buck Institute for Research on Aging in Novato, California, who pioneered work on senescence.
Campisi said in a statement that she hopes to treat age-related conditions as preventable and curable, rather than treating symptoms of diseases where the end is inevitable and debilitating. 鈥淚t is extraordinarily rewarding to see our discoveries move toward clinical trials.鈥�
Nature
