American scientists have developed a system that allows, based on the analysis of certain proteins in the blood that indicate the overall level of inflammation, to determine the biological age, predict the risk of developing cardiovascular diseases and estimate life expectancy. The results of the study are published in the journal Nature Aging.
Researchers from the Buck Institute and Stanford University, as part of the 1000 Immunomes project, studied blood samples from 1001 people aged eight to 96 years. The project aims to find out how the signs of chronic systemic inflammation change with age. Previously, the authors identified nine distinctive features of the aging process, now they have added a tenth-age-related dysfunction of the immune system, which, according to scientists, maybe the most informative.
“It becomes obvious that with age we should pay more attention to the immune system, given that almost every age-related disease has inflammation as part of its etiology,” the head of the study, Dr. David Furman, associate professor at the Buck Institute and director of the 1000 Immunomes project, is quoted in a press release from Stanford University. – With chronic inflammation, there is genomic instability, as well as mitochondrial dysfunction and problems with protein stability. Systemic chronic inflammation causes telomere depletion, as well as epigenetic changes.”
The authors identified a special biomarker of immune aging-chemokine CXCL9-in the immunome analyses of 1001 people. This protein, produced by the endothelium, helps activate the T-cells of the immune system. With age, as systemic inflammation increases, its release increases, which ultimately contributes to cellular aging and impaired blood vessel function.
However, some people show signs of systemic inflammation earlier, and others later. Using machine learning techniques, scientists have created the IAGE immune clock algorithm based on the association of the level of the CXCL9 protein in the blood with systemic inflammation — a program that allows not only to assess the state of the human immune and cardiovascular system and predict the rate of aging in the future.
“There are very few standard immune indicators that could be used to identify people who are most at risk of developing one or more chronic aging diseases,” says Dr. Furman. – Using an unbiased approach based on biology, we were able to identify some indicators, including a small immune protein that is involved in age-related systemic chronic inflammation and cardiac aging. Now we have the opportunity to detect age-related dysfunction at an early stage and intervene before the pathology occurs.”
The results of the initial analysis were confirmed by scientists in an independent cohort of centenarians who participated in the Framingham Heart Study, which has been conducted in the United States since 1948, in a separate group of 97 extremely healthy people aged 25 to 90 years from California, as well as among centenarians in Bologna in Italy. Everywhere, the authors found a correlation between the level of the CXCL9 protein, vascular stiffness, and premature aging.
According to the researchers, the iAge system measures the inflammatory load and predicts multiple diseases associated with aging, a decrease in immunity with age, and also explains the exceptional life expectancy of centenarians.
“On average, centenarians have an immune age about 40 years younger than what is considered normal. We have a separate case of a super-healthy 105-year-old man from Italy, whose immune system age is at the level of a 25-year-old person,” Furman says.
The authors believe that based on the iAge system, it is possible to create a new method for identifying the risks of developing age-related diseases associated with a decrease in immunity.