Scientists May Have Found the Secret to Living to 100 That Could Redefine Longevity

Human life expectancy has seen a remarkable rise over the past century. Back in 1900, the global average life expectancy was just 31 years. Fast forward to 2024, and this number has leaped to 73.3 years, with projections suggesting it may reach 77.1 years by 2050. Accompanying this are an increasing number of centenarians—individuals living to 100 years or older.

Research from 2015 estimated there were approximately 450,000 centenarians globally, a figure expected to rise to an astounding 3.7 million by 2050. Earlier studies in the 2000s predicted a surge in centenarians, estimating the global number would multiply fivefold between 2005 and 2030.

Despite this progress, what allows certain individuals to reach such extraordinary ages while others do not remains a mystery. Addressing this question, a study led by researchers from Tufts Medical Center and Boston University School of Medicine has uncovered a unique factor—centenarians exhibit distinct immune cell compositions and activity, giving them a robust immune system that could contribute to their exceptional longevity. These findings, published in Lancet eBioMedicine, hold promise for developing therapies aimed at healthy aging.

How Aging Affects the Immune System

Aging affects every part of the body, including the immune system. Dr. Scott Kaiser, a geriatrician and the director of Geriatric Cognitive Health at the Pacific Neuroscience Institute, highlights two primary changes associated with immune aging:

“One is immunosenescence and that’s the age-related process of immune dysfunction,” he explained to Medical News Today.

“So changes in our immune system composition and function over time can lead to poor immune function in older people. And that’s closely related to people’s vulnerability to infection, autoimmune disease, and even various types of cancer,” he said.

“And then there’s this issue of inflammaging, which is a term that’s been used to describe age-related increases in inflammation because of high levels of pro-inflammatory markers in the blood and different tissues in the body. That’s a strong risk factor for all sorts of diseases, including neurodegenerative processes like Alzheimer’s disease, for example,” Dr. Kaiser continued.

Dr. Kaiser also explains that the interplay between immune function and aging may either leave individuals vulnerable to diseases or protect them, based on how these systems evolve over time.

Examining Exceptional Immunity in Centenarians

To gain deeper insights, Dr. Tanya Karagiannis, senior bioinformatician at Tufts Medical Center and lead author of this study, and her team examined the immune systems of centenarians. She noted that aging alters the immune system’s function and structure, changes that can lead to age-related diseases.

“Many centenarians experience delays in the onset of aging-related disease and this suggests the presence of an elite immunity that continues to remain highly functional even at extreme old age,” she told Medical News Today.

The researchers performed single-cell sequencing on peripheral blood mononuclear cells (PBMCs) from centenarians participating in the New England Centenarian Study. This allowed them to analyze how immune cells differ across various age groups, particularly in extreme old age. Dr. Karagiannis explained:

“We used single-cell data and applied new computational methods to analyze immune cells that circulate through the immune system across the human lifespan. We looked at differences in the presence of specific immune cell types across younger ages and extreme old age and found cell type-specific changes in aging and extreme old age.”

The analysis revealed unique cell compositions and transcriptional patterns associated with exceptional longevity. These findings confirmed earlier observations regarding cell type-specific changes in centenarians’ immune responses.

Groundbreaking Genetic Insights in Centenarians

The study also provided intriguing insights into gene expression across ages. Researchers identified patterns specific to aging, as well as genes uniquely expressed in centenarians, which relate to their extraordinary lifespan.

“We were not as surprised to find genes that change with age in centenarians since they are an aging population. What was surprising was the different aging patterns we identified including genes that were aging-specific in which expression levels changed with age but not in extreme longevity across various cell populations,” said Dr. Karagiannis.

These findings pave the way for exploring drivers of extreme longevity and could potentially lead to therapeutics that promote healthy aging. Dr. Karagiannis added that future research will focus on understanding the longitudinal changes in immune cells in centenarians and younger individuals to identify key protective factors contributing to exceptional longevity.

Toward Therapeutics for Aging-Related Diseases

Reflecting on the study, Dr. Kaiser shared how significant it is to study individuals with extreme longevity to uncover what makes them uniquely resilient.

“The potential lessons here are in what makes us more resilient,” he explained.

“Looking at these people who had extreme longevity, living into 100s and even beyond, and figure out what is the nature, what is the characteristic of their immune system so that we could better understand what might be going on, and then figure out how that could be translated into potential therapies for other people, so that more people can enjoy that.”

Kathleen Cameron from the National Council on Aging’s Center for Healthy Aging also weighed in on the study. She emphasized the importance of understanding immune resilience to help people live longer and healthier lives:

“If we can determine what is creating this immune resilience for those who live over 100, that can lead to treatments that can help people live longer. Or, if there are certain healthy behaviors that lead to this resilience, that would also help us,” Cameron noted.

The Path Ahead

While promising, Cameron advised caution, noting the study included a small sample size and that further research is essential to validate these findings. Specifically, factors such as family history, lifestyle, and environmental influences on centenarians’ immune systems remain unknown and require further investigation.

“More research is needed to understand the effect these immune patterns have on longevity. Is there something in the centenarians’ family history or other things that happened in their life, exposure to certain things that might have changed their immune system? We don’t know that from this study. Knowing more about this could lead to new therapies or new ways to improve the immune system,” Cameron explained.

This groundbreaking study marks a step forward in understanding the link between immune resilience and extreme longevity. With further research, these findings could unlock new possibilities for innovative therapies, allowing more individuals to achieve healthy, long-lasting lives.

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