New blood test estimates organ age and predicts disease risk years before symptoms appear.
New research from Stanford Medicine suggests that individual organs inside the body age at different rates, and a simple blood test may one day reveal which organs are aging faster long before symptoms appear. The study, published in Nature Medicine, examined blood samples from 45,000 adults between the ages of 40 and 70. Researchers discovered patterns in thousands of blood proteins that allowed them to estimate the biological age of 11 different organs and organ systems, including the brain, heart, lungs, liver, kidneys and immune system. These findings suggest that knowing an organ’s biological age could help doctors predict the likelihood of developing diseases years ahead of time.
Researchers found that people with biologically older brains were much more likely to develop Alzheimer’s disease within the next decade than people whose brains appeared biologically younger. Those with younger-looking brains had a far lower risk, even when they were the same chronological age. The study’s senior author, Tony Wyss-Coray, said the brain appeared to have a particularly strong influence on overall lifespan, in general. In fact, according to the research, brain age was the best single predictor of a person’s risk of death over the study period.
To conduct the study, scientists used data from the UK Biobank, a large health project that has followed hundreds of thousands of volunteers over many years. Blood samples from 44,498 participants were analyzed using technology capable of measuring nearly 3,000 different proteins. Many of these proteins originate from specific organs. By studying their levels and comparing them with averages for people of the same age, researchers created an algorithm that estimated whether an organ appeared older or younger than expected. About one-third of participants had at least one organ that was considered either extremely aged or unusually youthful. One in four had several organs that fell into one of those categories.
The biological age of an organ often matched future health outcomes. Older hearts were linked to greater risks of heart failure and irregular heart rhythms. Older lungs were associated with a higher chance of developing chronic obstructive pulmonary disease, or COPD. Older kidneys and livers were tied to diseases affecting those organs.
The connection between brain age and Alzheimer’s disease stood out the most. Researchers found that someone with a biologically old brain was roughly 12 times more likely to develop Alzheimer’s over the following decade than a person of the same age whose brain appeared biologically young. The scientists believe this type of testing could eventually change how medicine is practiced overall. Instead of waiting for symptoms to appear, doctors may one day be able to identify organs that are aging too quickly and intervene sooner.
The research team recently expanded the work to predict diseases, looking beyond organs and examining individual cell types. That follow-up study also uncovered several important findings. For one, people who carried two copies of the APOE4 gene variant, one of the strongest known genetic risk factors for Alzheimer’s disease, tended to have older astrocytes (support cells in the brain). Yet some people with the high-risk gene still had healthier astrocytes and appeared protected from the disease. Researchers also discovered that people with youthful muscle cells had a dramatically lower risk of developing amyotrophic lateral sclerosis (ALS). The difference in risk was detectable more than three years before symptoms would normally appear.
The research team hopes the technology will become more affordable over the next few years by focusing on a smaller number of organs, such as the brain, heart and immune system. If successful, the test could help identify health risks earlier and give people a better chance of preventing the development of serious diseases long before they appear.
Sources:
Blood-based indicator assesses organ age to predict disease risk
Plasma proteomic signatures of cellular aging predict human disease
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