The different organs and tissues in the human body age at different speeds and the one that ages the fastest is the one that most influences the health and longevity of the person, according to research from Stanford University (USA) that finds the bases to better understand aging and develop therapies to counteract it. The authors of the research have developed a test based on a blood analysis that indicates the biological age of the different organs and tissues of the human body.
The research questions the idea that the entire organism has the same biological age, which may or may not coincide with the chronological age. The results indicate that each organ and tissue has its own biological age, which can be estimated from the proteins they release into the blood.
“A molecular understanding of the aging of human organs (...) could revolutionize patient care, preventive medicine and drug development,” the researchers write in the journal Nature, where they present their data today.
The work has been based on blood samples from 5,676 people in the United States who have participated in studies on aging and cognitive decline since 2008. Applying proteomics techniques, the levels of 4,979 proteins in the blood samples have been analyzed. Combining them with deep learning techniques, which is a branch of artificial intelligence, it has been identified which proteins inform the age of specific organs.
In one of the examples that were known before this research and that has been confirmed, transaminase levels provide information about the state of the liver. Other examples were not known and have now been discovered by combining proteomic analysis with artificial intelligence.
The results indicate that one in five apparently healthy people over 50 years of age have an organ that undergoes accelerated aging compared to the rest of the body. Researchers expected that accelerated aging would be synchronized between different organs in the body, but the data indicates the opposite: only one in 60 people has two or more organs that age rapidly. The Stanford University team concludes that the rate of aging not only varies between people, but also between different organs in each person.
Another expectation of researchers has been met: accelerated aging of an organ increases the risk of serious illness and premature death in the following years. For example, each extra year in the biological age of the heart increases the risk of heart failure by 23%. Accelerated aging of the kidneys increases the risk of developing diabetes or hypertension. And that of the muscles involves a more rapid deterioration in gait and a greater risk of falls.
“We can calculate the biological age of an organ in an apparently healthy person,” neurologist Tony Wyss-Coray, director of the research, states in a statement. “This in turn predicts the risk of disease related to this organ.”
Of the eleven organs and tissues that have been analyzed, there is no one that has a tendency to age faster than the others. In addition to the heart, kidneys and muscles, the brain, lungs, liver, pancreas, intestine, immune system, vascular system and fatty tissue have been analyzed.
Looking ahead, the researchers hope that some of the aging-associated proteins they have identified could guide the development of new drugs. They cite the example of the MYL7 protein, previously known but still little studied, as “a promising target for hypertrophic cardiomyopathy,” as they write in Nature.
Another perspective that is opening up is to expand the database with more organs and more proteins to achieve a more precise understanding of aging. “As more proteomics resources emerge, the potential of this strategy will increase. (...) We anticipate that more biological information can be obtained with more proteomic coverage," they write in Nature.
For now, the test to know the biological age of organs with a blood test is experimental. The director and two co-authors of the research have created the company Teal Omics so that the results of the project can be commercialized, made available to other doctors and scientists, and reach citizens.
