Could blocking this one protein extend human life span?

By blocking the action of a single protein, scientists have extended the average life span of the mice in their experiment by around 25%. This recent finding has raised the question of whether such a treatment could ever work for people, and so far, there are some promising early hints that it might.

In the new study, scientists injected middle-aged mice with an antibody that blocks the action of interleukin-11, a protein that spurs inflammation and has been tied to aging processes in human cells.

At the beginning of the experiment, these mice were about 17 months old, which is roughly equivalent to being 55 in human years. The mice received injections every three weeks until they died, while a comparison group of mice was left untreated.

The treated mice lived around 25% longer than their untreated counterparts, the researchers found.

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The treated rodents also maintained better health into old age. For instance, they were slimmer and stronger than the untreated mice, and they showed better liver function and metabolism. Furthermore, only 16% of the treated mice developed cancer, compared with 61% of the rodents that didn't receive antibody injections.

These findings suggest that targeting IL-11 could be a promising approach to combating the negative health impacts of aging, according to the team behind the new study, which was published Wednesday (July 17) in the journal Nature.

This is "very impressive work," said Joao Pedro de Magalhaes, a professor of molecular biogerontology at the University of Birmingham in the U.K. who was not involved in the research.

"While the role of the immune system in aging and its potential target to retard aging is well-established, IL-11 is a new important player for understanding the impact of the immune system and inflammation in aging," de Magalhaes told Live Science in an email.

Despite these encouraging results, though, much more research will be needed to determine if this kind of therapy would produce similar effects in humans. Scientists need to determine how blocking the action of IL-11 actually increases mice's lifespan. For now, that's unclear, de Magalhaes said. It's possible that the mice's longevity could stem mostly from the antibody preventing the onset of cancer in some way, as shown in the new study, he suggested. As in humans, cancer is a common cause of death in older mice.

The researchers behind the work hope to carry it into clinical trials, Anissa Widjaja, lead study author and an assistant professor at the Duke-NUS Medical School in Singapore, told Live Science.

Some treatments that target IL-11 are already in early-stage trials; these are being tested for age-related diseases, such as fibrotic lung disease, which involves excessive scarring of the lungs. Prior to these trials, past research had shown that IL-11 can induce fibrosis, so it's thought that blocking the protein might prevent this effect.

Such trials will help determine the efficacy and safety of any new therapies targeting IL-11. One potential concern with these treatments is that inflammation is an "important and necessary" component of the immune system, said Jason Kim, a professor of molecular medicine at the University of Massachusetts Chan Medical School who was not involved in the research. As such, blocking IL-11 with a drug could potentially have side effects that outweigh the proteins' positive effects on aging, Kim told Live Science in an email.

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For instance, anti-IL-11 treatments could theoretically make people more susceptible to other illnesses, including infections. This potential side effect wouldn't likely be obvious in lab mice, as they are kept in clean environments free of pathogens, de Magalhaes noted.

Nevertheless, the possibilities for this research are exciting, Widjaja said. She and her team are now investigating whether short-term treatment with the IL-11-targeting antibodies might also have anti-aging benefits in mice.

"People are already living longer now, so the question is whether they can stay healthy for longer," she said. "It is very hopeful that our research has shown that anti-IL-11 therapy can help us achieve that."

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