Researchers at the Dana-Farber Cancer Institute at Harvard Medical School were able to dramatically reverse the ageing process in mice — which had been bred to age prematurely, because they lacked telomerase:
Without the enzyme, the mice aged prematurely and suffered ailments, including a poor sense of smell, smaller brain size, infertility and damaged intestines and spleens. But when DePinho gave the mice injections to reactivate the enzyme, it repaired the damaged tissues and reversed the signs of ageing.
“These were severely aged animals, but after a month of treatment they showed a substantial restoration, including the growth of new neurons in their brains,” said DePinho.
Repeating the trick in humans will be more difficult. Mice make telomerase throughout their lives, but the enzyme is switched off in adult humans, an evolutionary compromise that stops cells growing out of control and turning into cancer. Raising levels of telomerase in people might slow the ageing process, but it makes the risk of cancer soar.