At Nature, Smriti Mallapaty reports on a study that could not have been done until at least the twentieth century: It is on a A bank of cells from people who have lived to be more than 100 years old, which provides a chance to study human longevity.

Scientists in Boston, Massachusetts have made reprogrammed stem cells from the blood of centenarians. They plan to share the cells with other researchers to better understand the factors that contribute to a long and healthy life. Early experiments are already providing insights on brain ageing.

Centenarians offer an opportunity to study longevity. People who’ve lived to 100 have an amazing ability to bounce back from insult and injury, says George Murphy, a stem-cell biologist at the Boston University Chobanian & Avedisian School of Medicine. One centenarian he knows recovered from the 1912 Spanish flu and COVID-19, twice. One theory that explains centenarians’ robust age is that they possess a genetic makeup that protects them from diseases.

“What’s the secret to living to 100? Centenarian stem cells could offer clues,” November 29, 2024

One problem is that up to now there have not been lab models for human aging (as opposed to, say, aging in rats). While most people will not likely live to be centenarians, in an age when longevity is increasing, healthier old age becomes an important goal. First author of the study Todd Dowrey commented,

“By creating centenarian stem cells, we hope to decipher how these individuals delay or avoid age-related diseases and develop and/or validate therapeutics in this same capacity. This research provides a unique resource that can be used to better understand the mechanisms behind centenarian resilience and help others maximize their healthy years of life.”

Boston University School of Medicine. “Researchers establish stem cell repository focused on centenarians.” ScienceDaily, 25 September 2024. The paper is open access.

Amanda Ruggeri notes at the BBC that while life expectancy has not increased, far more humans are surviving into a natural old age:

The average person born in 1960, the earliest year the United Nations began keeping global data, could expect to live to 52.5 years of age. Today, the average is 72. In the UK, where records have been kept longer, this trend is even greater. In 1841, a baby girl was expected to live to just 42 years of age, a boy to 40. In 2016, a baby girl could expect to reach 83; a boy, 79.

“Do we really live longer than our ancestors?,” October 2, 2018

The super old

Of course, with more people avoiding early deaths, some are bound to exceed normal life expectancies. According to the Guinness Book of Records, the oldest reliably confirmed human being ever was Jeanne Louise Calment of Arles, France (1875–1997) at 122 years. A close rival, also in France, was Sister André (1904–2023) , aged 118 years. A Japanese woman, Kane Tanaka, survived to 119 years (1903–2022).

Researchers want to know more about how all this works.