Written by Alison Proffitt
Researchers at Stanford University have developed a blood test that reveals the functional age of your organs, predicts your odds of developing certain organ diseases within ten years, and opens new diagnostic methods.
“Using this index, we can assess the age of an organ today and predict your odds of developing a disease related to that organ in 10 years,” said Tony Weiss-Coray, professor of neuroscience and neuroscience and director of the Knight Brain Plasticity Initiative at the Wu Tsai Neuroscience Institute at Stanford University.
Last year, Wes Coray and his lab published a paper in Natural medicine (doi: 10.1038/s41591-025-03798-1) shows how proteins collected through a blood draw can predict organ health for 11 separate systems: brain, muscle, heart, lung, arteries, liver, kidneys, pancreas, immune system, intestines, and fat.
In a study also published yesterday in Natural medicine (DOI: 10.1038/s41591-026-04446-y), Wyss-Coray and colleagues have shown that not only our organs, but also individual cell types within those organs, can be classified by biological rather than chronological age, revealing more precise data that enables potentially superior diagnostic approaches.
Age by protein signature
The scientists studied 44,498 randomly selected participants, aged between 40 and 70, from the UK Biobank. These participants were monitored for up to 17 years for changes in their health. They used SomaLogic’s SomaScan platform and Olink Proteomics to measure the amounts of nearly 3,000 proteins in each participant’s blood. About 15% of these proteins can be traced to single-organ origins, and many others to multi-organ origins.
The researchers fed everyone’s blood-borne protein levels into an algorithm that compared an individual’s blood protein signature with the general average for people that age and assigned a biological age to each of the 11 distinct organs or organ systems evaluated for each subject. These protein signatures serve as proxies for the relative biological conditions of individual organs. A standard deviation greater than 1.5 from the mean places a person’s organ in the “old” or “very young” category.
The algorithm also predicted people’s future health, organ by organ, based on the current biological age of their organs. Wyss-Coray and colleagues examined associations between very old organs and any of 15 different disorders, including Alzheimer’s disease, Parkinson’s disease, chronic liver or kidney disease, type 2 diabetes, two different heart conditions, two different lung diseases, rheumatoid arthritis, osteoporosis, and more.
The risks of many of these diseases were influenced by the biological age of many different organs, but the strongest associations were between the organ of an individual’s biological age and that individual’s chance of developing a disease associated with that organ. For example, having an older heart predicts a higher risk of atrial fibrillation or heart failure. Older lungs predict an increased risk of developing chronic obstructive pulmonary disease (COPD); Having an older brain predicts an increased risk of developing Alzheimer’s disease.
Aside from brain disease alone, brain age was the single best predictor of overall mortality.
“The brain is the gatekeeper to longevity,” Wes Coray said. “If you have an old brain, you will have an increased probability of dying. If you have a young brain, you will likely live longer.”
Having an aging brain increases a person’s risk of death by 182% over a period of approximately 15 years, while individuals with very young brains have an overall 40% reduction in risk of death over the same period.
Not organs but cell types
The study published this week expanded these findings to include not only organ system but cell type. The researchers used single-cell transcriptomic data in the Human Protein Atlas to link 60 cell types to their corresponding plasma proteins, and classified genes as cell type specific if they were expressed at least two times higher in one cell type than in any other.
They then analyzed proteins measured in blood from 60,542 individuals from the UK Biobank, the World Neurodegeneration Proteomics Consortium, and the 1946 National Survey of Health and Development. They estimated the biological age of more than 40 cell types that include neuronal, immune, glial, endocrine, epithelial, and skeletal muscle cells.
What they found is that cell types age at different rates, and their aging pathways can be captured by differences in plasma protein abundance. The researchers wrote that 20%-25% of individuals showed accelerated aging in one cell type, and 1%-3% in 10 or more cell types. “Certain cell populations—such as excitatory neurons, Schwann cells, natural killer cells, macrophages, skeletal muscle cells, and fibroblasts—have emerged as potential ‘aging centers,’ showing associations with multiple other cell types,” the authors wrote. “In contrast, epithelial cell types tend to show more isolated or weakly associated age gap profiles.”
Cell aging and diseases
Across cell types, the researchers found that cells that accelerate aging were linked to disease.
For example, individuals with older than young skeletal muscle cells showed a 12.7-fold higher risk of developing amyotrophic lateral sclerosis. For lung cancer, severe senescence in alveolar type 2 cells and the broader respiratory epithelial lineage was most prognostic. For chronic obstructive pulmonary disease (COPD), severe senescence in alveolar type 2 cells and the broader respiratory epithelial lineage has shown prognostic strength. For heart failure, severe senescence in muscle cells and fibroblasts was the most alarming.
Alzheimer’s disease has been associated with accelerated aging across a wide range of cell types, but astrocyte senescence was a particularly powerful biomarker that stratified disease risk independently of and in synergy with it. APOE Genotype. “Preserving the function of young astrocytes may be a potential therapeutic strategy to alleviate the burden of disease, especially in genetically predisposed individuals,” the authors hypothesized.
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“The non-invasive, blood-based approach presented in this study enables the description of biological aging at cellular resolution, providing a new framework for studying the heterogeneity of aging and potential disease mechanisms relevant to treatment,” the researchers wrote in their discussion. “Future work should explore the epigenetic progression and genetic basis of cellular aging. Furthermore, complimentary analysis of lifestyle factors and ultra-high growth cohorts could identify proteomic signatures underlying exceptional longevity, resilience and regeneration at the cellular level.”
Although the analytical tool is now only available for research purposes, Wyss-Coray has plans to commercialize it. He is a co-founder and chief scientific officer of Teal Omics and Vero Bioscience, two companies from which Stanford University’s Office of Technology Licensing has licensed technology developed in this and related research to commercialize screens for novel drug targets and consumer products, respectively.
The test may be available within the next two or three years, Weiss-Coray said in a press release. “The cost will decrease when we focus on fewer key organs, such as the brain, heart and immune system, to get more specificity and stronger links to specific diseases.”
