Scientists Gave Old Mice Blood of the Young and It Made Them Live Longer and Look Younger

Scientists who dosed old mice with an enzyme from the blood of young mice say it extended their lives by 16 percent, as well as making them look younger.

Treating the older mice with an enzyme from the blood of younger mice appeared to slow processes linked to aging, according to the authors of the study published in the journal Cell Metabolism.

The study looked at a molecule called Nicotinamide Adenine Dinucleotide (NAD), which is found in all living cells and plays a role in generating energy. It has previously been shown to decline as we age. An enzyme called extracellular nicotinamide phosphoribosyltransferase, or eNAMPT, is important for creating NAD.

In lab tests on mice, the team found levels of eNAMPT in the fat tissue of mice—from where it is released—dropped by 33 percent at the age of 6 months to 74 percent in the mice. Those with more eNAMPT in their bodies lived longer.

They also tested whether giving older animals the blood component eNAMPT could help slow aging and increase their lifespan by keeping NAD production going.

After being dosed with eNAMPT, the mice seemed to reap benefits across their bodies.

They were better at producing insulin, the cells in their eyes respond to light worked better, their sleep quality improved, and they could run for longer on exercise wheels. When the mice carried out memory tests, their cognitive functions appeared to have become slicker.

The enzyme moves particles called extracellular vesicles around the body. The researchers gave mice aged 26 months extracellular vesicles containing eNAMPT from young to middle-aged mice between 4 to 12 months old. They did this once a week, and found they lived longer compared with mice in the control group mice given a saline solution.

Dr. Shin-ichiro Imai, a professor of developmental biology at Washington University School of Medicine and senior author of the study commented in a statement: "We have found a totally new pathway toward healthy aging."

"We were surprised by the dramatic differences between the old mice that received the eNAMPT of young mice and old mice that received saline as a control," he said.

"These are old mice with no special genetic modifications, and when supplemented with eNAMPT, their wheel-running behaviors, sleep patterns and physical appearance -- thicker, shinier fur, for example -- resemble that of young mice."

He said: "That we can take eNAMPT from the blood of young mice and give it to older mice and see that the older mice show marked improvements in health—including increased physical activity and better sleep—is remarkable."

However, Imai cautioned it's not yet clear whether giving humans eNAMPT would have the same effect.

"But it does suggest that eNAMPT levels should be studied further to see if it could be used as a potential biomarker of aging," he said.

In 2017, scientists gave mice a type of NAD, and found their activity of an enzyme was restored, and the mice were rejuvenated. The findings were published in the journal Science.

Imai told Newsweek: "It has been known that young blood has a capability of enhancing physiological functions in aged individuals.

"However, nobody has ever demonstrated that aging can be delayed and lifespan can be extended by any factor in blood circulation."

He said this is the first attempt to demonstrate a specific component in young blood, namely, eNAMPT-containing extracellular vesicles, to delay aging and extend lifespan in mice.

"Furthermore, humans also have exactly the same component in our blood circulation. The way that NAMPT works is also exactly the same between mice and humans," said Imai.

Therefore, similar effects of eNAMPT-containing EVs could be expected in humans as well."

A separate paper published in the journal Nature Communications earlier this year saw a team of scientists take a different approach to the study of aging. They found the Angelica keiskei koidzumi plant, commonly known as ashitaba, used in traditional Asian medicine contains a compound that could slow this process.

The researchers identified the flavonoid 4,4′-dimethoxychalcone, which they described as a "natural compound with anti-aging properties," in the plant.

This article has been updated with comment from Dr. Shin-ichiro Imai.