Researchers Find 13 Proteins in the Blood That Are Seemingly Linked to Brain Aging

Chinese neurologists have identified 13 proteins in the blood that appear to be good indicators of how fast our brains age.

In the future, this information could help monitor aging in the brain and keep tabs on age-related cognitive disorders, like dementia. But other experts say a closer investigation is needed before we can be certain that these proteins are truly tied to brain aging.

In a paper published this month in Nature Aging, a team of scientists analyzed almost 11,000 magnetic resonance imaging (MRI) brain scans from people ages 45 to 82 that were included in the U.K. Biobank. They used artificial intelligence to determine the “brain age” of the scans based on features including brain volume and surface area—essentially, they predicted how old a person is based on their brain data. This “brain age” number can be different from the chronological age of the individual and can shed light on cognitive aging and risk for neurodegenerative diseases.

“The higher the A.I.-predicted age is relative to their actual age, the faster their brain is aging,” explains study lead author Wei-Shi Liu, a neurologist at Fudan University in Shanghai, to New Scientist’s Carissa Wong.

Next, researchers appraised the concentration of 3,000 proteins in the participants’ blood, to determine which proteins—delivered to the brain via blood vessels—were associated with brain age. They concluded that 13 proteins—eight linked to fast brain aging, and five linked to slow aging—appeared connected to the brain age. Certain proteins that affect cellular stress and inflammation increased with age, while others that help with maintenance tasks like cell regeneration dwindled, reports Live Science’s Emily Cooke.

Determining this correlation is a notable feat, as previous studies with the same objective had involved fewer than 1,000 people, Nicholas Seyfried, a neurologist at Emory University who was not involved in the study, tells New Scientist. Not only that, the scientists’ focus on brain age sets the study apart from previous work that examined proteins alongside the real age of the individual, as Liu tells Nature News’ Miryam Naddaf.

Studying biomarkers related to an individual’s biological brain age could be a more targeted approach for finding and identifying age-related issues with the brain. And for Liu’s team, this allowed for a direct analysis of the protein composition in the blood of individuals with a large gap between their brain age and actual age.

They also found that certain proteins linked to brain aging underwent significant changes in level at the brain ages of 57, 70 and 78, per the paper. These peaks have “different implications,” which may be helpful in the early diagnosis and treatment of brain disorders, Liu says to Nature News.

For instance, blood tests for these proteins could provide critical information about how fast an individual’s brain is aging. “These markers could be the canary in the coal mine to tell you, ‘hey, look, let’s start intervening to slow your brain aging now, while you’ve got enough time,’” Seyfried says to New Scientist.

However, some experts have pointed to limitations of the study’s findings, which Liu’s team has also acknowledged. The idea that aging comes in three waves goes “against pretty much everything that is known about brain aging,” says Mark Mattson, a neuroscientist at Johns Hopkins School of Medicine who was not involved in the study, to Live Science.

Additionally, exactly where these 13 proteins come from in the brain is unknown. “Until levels of those proteins in the brain are established, it will be unclear whether they actually play a role in brain aging,” Mattson adds. But he did find the correlations with brain age “interesting.”

Others also point out that the individuals studied for the paper were mostly white, wealthy people. Further research involving more diverse ethnicities and income levels will be necessary to determine whether the results are more widely applicable.

Nevertheless, Liu is hopeful that the 13 proteins his team identified could help guide future treatments for brain diseases. With these comments in mind, the team now plans to continue with their research and address others’ concerns. “In the next couple decades, this could open up ways to target the proteins to slow aging and disease,” he tells New Scientist.

Gayoung Lee | | READ MORE

Gayoung Lee is a science journalist from South Korea, now based in New York. Her main interest lies in exploring the unlikely connections between science and everyday life.