A human body contains about 30 trillion cells, and the immune system, in particular, plays a crucial role in how well these cells interact and support one another to maintain our health. A decline in the proper operation of our immune system is one of the hallmarks of aging. A small group of people known as centenarians experience delays in aging-related illnesses and mortality, suggesting that their immune systems continue to function well into old age.
According to a recent study led by scientists from Boston University’s Chobanian and Avedisian School of Medicine and Tufts Medical Center, centenarians have immune systems that are highly functional and have successfully adapted to a history of illness, which has allowed for exceptional longevity. These immune cells might be useful in identifying crucial healing and longevity-promoting mechanisms.
Lead author Tanya Karagiannis, Ph.D., stated that the findings “support the hypothesis that centenarians have protective factors that enable them to recover from disease and reach extreme old ages.”. D., a senior bioinformatician at Tufts Medical Center’s Center for Quantitative Methods and Data Science, Institute for Clinical Research, and Health Policy Studies.
“Our findings support the concept that centenarians have protective mechanisms that allow them to recover from sickness and live to extreme old ages,”
Lead author Tanya Karagiannis, Ph.D.,
According to senior author Stefano Monti, Ph., “We assembled and analyzed what is, to our knowledge, the largest single-cell dataset of centenarian subjects, allowing us to define unique features of this population that support the identification of molecular and lifestyle factors contributing to their longevity.” D. at the School of Medicine as an associate professor of medicine.
Peripheral blood mononuclear cells (PBMCs), a large class of immune cells circulating in the blood, were taken from seven centenarians participating in the New England Centenarian Study, one of the largest studies of long-lived people in North America, directed by Thomas Perls, MD, at the School of Medicine. Single-cell sequencing was then performed on these immune-specific patterns of aging and extreme human longevity.
In order to investigate compositional and transcriptional changes in circulating immune profiles throughout the human lifespan and in extreme old age, the researchers combined this dataset with two other publicly available single-cell RNA sequencing (scRNA-seq) datasets of PBMCs.
Finally, they used cutting-edge computational techniques to analyze the combined data, determine whether centenarians manifest profiles capturing or escaping the expected age progression, and assess how the cell type composition (the ratio of different cell types) and activity change with age.
In addition to identifying novel compositional and transcriptional changes that are specific to centenarians and reflect a healthy immune response, their analysis supports findings from earlier studies of aging.
The immune system can adapt when people are exposed to infections and recover from them, but as we age, our immune systems’ capacity to do so decreases.
Senior author Paola Sebastiani, Ph.D., stated that the immune profiles of the centenarians “confirm a long history of exposure to infections and capacity to recover from them” and “provide support to the hypothesis that centenarians are enriched for protective factors that increase their ability to recover from infections.” D. Director of the Center for Quantitative Methods and Data Science at Tufts Medical Center’s Institute for Clinical Research and Health Policy Studies.
These results, in the opinion of the researchers, lay a solid foundation for further research into immune resilience mechanisms that may be responsible for extreme longevity and serve as a target for healthy aging therapeutics. ” Centenarians and their extraordinary longevity offer a ‘blueprint’ for how we might lead more fruitful, healthy lives. Senior author George J. said, “Our goal is to continue learning everything we can about disease resistance and extending one’s health span. Patrick Murphy, Ph.D., is a medical associate professor at the school of medicine.
These discoveries are published in eBiomedicine online.
More information: Tanya T. Karagiannis et al, Multi-modal profiling of peripheral blood cells across the human lifespan reveals distinct immune cell signatures of aging and longevity, eBioMedicine (2023). DOI: 10.1016/j.ebiom.2023.104514
