Summary: A large new study shows that different organs in the same person can age at different rates, and those differences predict future disease risk and even overall survival. Using plasma protein signatures measured in blood from over 44,000 participants, researchers created an algorithm that estimates the biological age of 11 organ systems and links those organ ages to later disease and mortality.
The analysis found that the biological age of the brain is particularly influential: an older-appearing brain strongly predicts Alzheimer’s disease and higher mortality, while a biologically younger brain is protective. This blood-based organ-aging approach could change clinical practice by enabling earlier risk detection and more targeted prevention.
Key Facts:
- Organ-specific biological age: Different organs can be biologically older or younger than a person’s chronological age, and these differences signal organ-specific disease risk.
- Brain age is highly predictive: A biologically old brain increases Alzheimer’s risk roughly threefold and nearly doubles overall mortality in the study cohort.
- Clinical potential: Plasma proteomics-based organ-age measures may allow clinicians to identify high-risk individuals and intervene before symptoms appear.
Source: Stanford
The number of birthday candles does not reflect biological reality. While chronological age is fixed, our tissues age at varying speeds, and these differences matter for future health.
People commonly estimate age from visible signs such as facial wrinkles, but assessing the biological age of internal organs has been challenging. Researchers at Stanford Medicine developed a blood-based method that uses circulating proteins as organ-specific biomarkers to estimate the biological age of internal systems and predict future health outcomes.
“We’ve developed a blood-based indicator of organ age,” said Tony Wyss-Coray, PhD, professor of neurology and neurological sciences and director of the Knight Initiative for Brain Resilience. “This indicator lets us measure an organ’s biological age now and estimate the odds of developing an organ-related disease up to a decade later.”
The team applied this approach to 11 organ systems: brain, muscle, heart, lung, arteries, liver, kidneys, pancreas, immune system, intestine and fat. Their results show that an organ’s biological age—derived from blood protein patterns—correlates with future organ-specific disease and with overall survival.
Wyss-Coray emphasized the brain’s role: “The brain appears to be a key gatekeeper of longevity. A biologically older brain substantially raises mortality risk, whereas a biologically younger brain is associated with longer survival.”
Study design and proteomic analysis
The study examined 44,498 adults aged 40 to 70 who were enrolled in the UK Biobank and followed for up to 17 years. Investigators measured nearly 3,000 plasma proteins per participant using a high-throughput proteomics platform. Approximately 15% of those proteins are known to originate primarily from a single organ, while others reflect signals from multiple tissues.
Researchers computed age-adjusted average protein levels for each organ-associated protein, then used machine learning to generate composite protein “signatures” for each organ. Comparing an individual’s organ-specific protein signature to the age-adjusted average produced an organ biological-age score. Deviations of more than 1.5 standard deviations were categorized as “extremely aged” or “extremely youthful.”
About one-third of participants had at least one organ in the extremely aged or youthful range, and one in four had multiple organs in those extreme categories. For the brain, the most extreme 6–7% of signatures were labeled “extremely aged” and the opposite 6–7% were “extremely youthful.”
Organ age predicts disease and mortality
The investigators tested whether an organ’s biological age forecast the later onset of 15 different conditions, including Alzheimer’s disease, Parkinson’s disease, type 2 diabetes, chronic liver or kidney disease, atrial fibrillation, heart failure, COPD and arthritis. In general, an aged organ raised the risk of developing diseases that affect that organ: an aged heart predicted higher risk of atrial fibrillation and heart failure, aged lungs predicted COPD, and an aged brain strongly forecast Alzheimer’s disease.
The link between brain age and Alzheimer’s was especially strong. Individuals with an extremely aged brain faced a 3.1-fold increased risk of developing Alzheimer’s compared with those whose brains appeared age-typical; conversely, an extremely youthful brain conferred a roughly 74% reduction in Alzheimer’s risk compared with a normally aging brain. Put differently, a biologically old brain was associated with an approximately 12-fold greater chance of receiving a new Alzheimer’s diagnosis over the following decade than a same-age person with a biologically young brain.
Brain age was also the single best predictor of overall mortality: having an extremely aged brain increased mortality risk by 182% over about 15 years, while an extremely youthful brain reduced mortality risk by about 40% over the same interval.
Implications for prevention and clinical trials
This plasma proteomics approach offers a way to identify high-risk individuals before symptoms appear. Wyss-Coray suggests organ-age measurements could be used as surrogate markers in trials that test lifestyle changes, drugs or other interventions aimed at slowing or reversing organ aging. By tracking organ-specific biological age alongside lifestyle and medication data, researchers could assess which interventions preserve organ youth and reduce disease risk.
Although the tool is currently a research assay, plans are under way to commercialize a clinical version. The developers expect testing costs to fall as assays focus on a smaller set of priority organs—such as brain, heart and immune system—while improving predictive accuracy for specific diseases.
Funding: The work was supported by the National Institutes of Health (grants P50AG047366 and P30AG066515), the Milky Way Foundation, the Knight Initiative for Brain Resilience and the Stanford Alzheimer’s Disease Research Center.
About this brain aging and longevity research news
Author: Bruce Goldman
Source: Stanford
Contact: Bruce Goldman – Stanford
Image: The image is credited to Neuroscience News
Original Research: Open access. “Plasma proteomics links brain and immune system aging with healthspan and longevity” by Tony Wyss-Coray et al., published in Nature Medicine.
Abstract
Plasma proteomics links brain and immune system aging with healthspan and longevity
Plasma proteins that originate from specific organs can be used to estimate organ biological age and predict mortality, but questions remained about how lifestyle, medications and environmental factors influence these measures and how well they forecast organ-specific disease onset.
To address these gaps, the authors estimated the biological age of 11 organs using plasma proteomics data (2,916 proteins) from 44,498 UK Biobank participants. Organ-age estimates were sensitive to lifestyle factors and medications and associated with incident disease over up to 17 years of follow-up, including heart failure, COPD, type 2 diabetes and Alzheimer’s disease.
Notably, an especially aged brain posed an Alzheimer’s risk (hazard ratio = 3.1) comparable to carrying one copy of APOE4, a major genetic risk factor for sporadic Alzheimer’s disease, whereas a youthful brain (HR = 0.26) provided protection similar to carrying two copies of APOE2, independently of APOE genotype. Accumulation of multiple aged organs progressively raised mortality risk (2–4 aged organs, HR = 2.3; 5–7 aged organs, HR = 4.5; 8+ aged organs, HR = 8.3), while youthful brain and immune-system signatures were uniquely associated with longevity (youthful brain HR = 0.60; youthful immune system HR = 0.58; both youthful HR = 0.44).
Overall, these results support using plasma protein profiles to monitor organ health and highlight the brain and immune system as promising targets for longevity interventions.