Your chronological age seems to be just a number. What is more important for understanding disease risks is the biological age of each of your organs.
New Discovery
A new study has shown that bodily organs age at exceptionally different rates, and the age of each organ can be inconsistent with the person’s chronological age. The study identifies about one in five healthy adults over the age of 50 as “extremely aging” individuals—someone with at least one organ aging at an accelerated rate compared to a group of their peers. The research team measured proteins related to organs, including the brain, heart, immune tissues, and kidneys. Researchers hope that their findings will lead to a future blood test that can identify organs aging rapidly, allowing doctors to target them for treatment before disease symptoms begin.
Current Research
The team took blood samples from more than 5,500 individuals, all of whom had no active diseases or clinically abnormal vital signs, to search for proteins emanating from specific organs. The scientists were able to pinpoint the source of these proteins by measuring the activity of their genes: when a protein’s genes are expressed at four times the rate in one organ, it means they originate from there. The team then measured the concentrations of thousands of proteins in a drop of blood and found that about 900 of them—roughly 18 percent of the measured proteins—were likely specific to just one organ. When these proteins differed from the expected concentration for a particular chronological age, it indicated aging in the corresponding organ.
Impact of Accelerated Aging on Health
By comparing the organ-specific proteins of study participants, researchers were able to estimate the age gap—the difference between the biological age of the organ and its chronological age. Depending on the organ in question, participants found to have at least one organ with accelerated aging had higher disease risks and mortality rates over the next 15 years. For example, those whose hearts were “older” than usual had more than double the risk of heart failure compared to individuals with normally aging hearts. Additionally, aging in the brain was a strong predictor of cognitive decline. Accelerated aging in the brain and vascular system predicted Alzheimer’s disease progression with the same strength as the blood protein marker pTau-181—the current clinical biomarker for the condition. Extreme aging in the kidneys was also a strong predictor of high blood pressure and diabetes.
Impact of Environmental Factors
Paul Shiels, a professor of cell gerontology at the University of Glasgow who was not involved in the new research, stated that the study was robust due to its large sample sizes. However, he noted that the age range of included individuals was “a bit narrow.” He said, “They only looked at older individuals, which did not represent the entire life course.”
Future Blood Test
Measurements of biological aging are an emerging science. “Epigenetic clocks,” a pioneering approach developed by Steve Horvath from the research technology company Altos Labs, examine DNA changes to determine tissue age more accurately than other current estimates of organ age. As people age, the body begins to accumulate DNA signatures that can indicate the age of a cell or organ; this allows for age estimations. However, epigenetic clocks estimate the age of the organism rather than a specific organ’s age, according to Weiss Kurai.
Personalized Diagnosis
This research could lead to a simple blood test that can guide diagnostic work— in other words, a test that can help predict future disease. You may begin to take interventions before the disease develops, potentially reversing or slowing down this accelerated aging.
Diagnosis
Personal
This research is part of the growing field of personal diagnostics, which is based on the idea that many biomarkers of organ health can help doctors target treatments. Blood measurements have traditionally been used to identify diseases in the body, with doctors diagnosing only after a person surpasses a certain threshold indicator. However, with improved sensitivity of protein markers, “you can actually detect something abnormal before clinical symptoms appear,” according to Weiss Korai. He and his colleagues have incorporated this research into a recently submitted patent associated with their startup Teal Omics, which focuses on precision medicine through biomarker testing.
Commercial Aging Tests
Some companies, primarily based in California, offer blood, urine, or saliva tests that claim to determine a person’s overall biological age. The momentum of commercial epigenetic testing is described as a “gold mine,” according to Schiels. “There is a degree of exaggeration about what [the tests] can do.”
Factors Influencing Aging
No single organ tells the whole story of aging because the processes of deterioration are interconnected and affect the entire organism. “We understand a lot about the aging process at a microscopic level,” says Schiels. “But many of the factors driving age-related organ dysfunction are environmental. It’s lifestyle, pollution, what you eat, and the microbes in your digestive system.”
The Importance of Organs
According to Weiss Korai, every organ is essential to overall health. The human body is like a car: “If one part isn’t working well, the other parts start to suffer,” he says. “If you maintain certain parts, you can extend the life of the car.”
Copyright and Permissions: Lori Youmshajekian is a science journalist based in New York City covering health and the environment. She was previously a television journalist and video reporter at the Australian Broadcasting Corporation (ABC), focusing on pandemic policy and international news. In 2020, she won two journalism awards for her contributions to a campaign supporting sexual assault survivors. Currently, she is pursuing a master’s degree in science, health, and environmental reporting at New York University. Follow Youmshajekian on X (formerly Twitter) @youmshajekian
Source: https://www.scientificamerican.com/article/your-organs-might-be-aging-at-different-rates/
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