Woman aging
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Researchers at the University of Pittsburgh say they have discovered blood-based biomarkers that are linked to both healthy aging and rapid aging allowing for a more precise prediction of an individual’s biological age. Biological age is a measure of how fast a person’s cells and organs age regardless of their chronological age.

The research, published last week in the journal Aging Cell, highlights potential pathways and compounds that may underlie biological age and provides new insights as to why people age differently. These new findings have the potential to suggest targets for interventions to slow aging and promote a longer health span.

“Age is more than just a number,” said senior author Aditi Gurkar, PhD, assistant professor of geriatric medicine at Pitt’s School of Medicine. “Imagine two people aged 65: One rides a bike to work and goes skiing on the weekends, and the other can’t climb a flight of stairs. They have the same chronological age, but very different biological ages.”

Gurkar, who is also a member of the Aging Institute, a joint venture between Pitt and the University of Pittsburg Medical Center (UPMC), focuses her research to discover why people age so differently. In this new research, Gukar and the UPMC team compared 196 older adults classified the participants as either healthy or rapid agers by how easily they completed simple walking challengers. The investigators used these measures as previous research has demonstrated that walking is a holistic measure of health such as cardiovascular fitness, physical strength, and neurological health. It has also been shown to be one of the best predictors of hospitalization, disability, and functional decline in older adults.

The Pitt researchers defined healthy agers as those 75 years or older who could ascend a flight of stairs or walk for 15 minutes without resting. Rapid agers, aged 65 to 75 years old, had to rest during these challenges. What differentiated this study for others examining chronological age was including rapid agers who were chronologically younger than the healthy agers. This allowed for better identification of markers of biological aging, as opposed to studies that have compared young adults to those who are much older.

“Other studies have looked at genetics to measure biological aging, but genes are very static: the genes you’re born with are the genes you die with,” said Gurkar. “We chose to look at metabolites because they are dynamic: They change in real time to reflect our current health and how we feel, and we have the power to influence them through our lifestyles, diet, and environment.”

The data showed that healthy agers and rapid agers had clear differences in their metabolomic profiles which pointed to the potential of that certain metabolites in the blood could reflect a person’s biological age. Using these findings the team identified 25 metabolites to create the Metabolic (HAM) Index, which they contend is better at determining biological age than measures such as the frailty index, gait speed, and the Montreal Cognitive Assessment.

To validate the HAM index the researchers analyzed the metabolites of a separate cohort of adults from a Wisconsin-based study and found that it could accurately predict which individuals could walk for 10 minutes with resting with an accuracy around 68%.

Continuing along this line of research, Gurkar and her team then employed an artificial intelligence model that predicts the potential driver of biological traits and narrowed their list from 25 metabolites to the three main ones that are mostly likely to promote either healthy aging or drive rapid aging.

Future research will now focus on better understanding how the molecular pathways in the body that produce these metabolites contribute to biological aging and to possibly identify interventions that decrease the rate of biological again. Gurkar also plans to research younger people to discover how their metabolomes change over time with the goal to develop a blood test that can be predictive of people who may be more susceptible to developing diseases of aging.“While it’s great that we can predict biological aging in older adults, what would be even more exciting is a blood test that, for example, can tell someone who’s 35 that they have a biological age more like a 45-year-old,” Gurkar said. “That person could then think about changing aspects of their lifestyle early—whether that’s improving their sleep, diet or exercise regime—to hopefully reverse their biological age.”

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