Researchers here demonstrate that a biomarker of aging presently under development shows a lower measure of age in the children of long-lived individuals. A number of research groups are involved in trying to create a standard measure of biological age based on patterns of DNA methylation, a type of epigenetic modification that regulates the production of specific proteins from their genetic blueprints. Cells react to circumstances, and one of those circumstances is the accumulation of molecular damage that causes aging. These forms of damage are the same in all of us, and so we should expect to find patterns in the epigenetic changes that accompany aging: some are individual, a matter of circumstances and environment, but others are shared and reflect the level of age-related cell and tissue damage suffered over the years.
Ageing researchers and the general public have long been intrigued by centenarians. We find it useful to further distinguish centenarians from semi-supercentenarians (i.e. subjects that reach the age of 105 years, 105+) and supercentenarians (subjects that reach the age of 110 years, 110+) because subjects in these latter categories are extremely rare. As of January 1, 2015, in the 60,795,612 living individuals in Italy, 100+ are 19,095, 105+ are 872, and 110+, which constitute an even smaller subgroup, are 27, according to the data base from the Italian National Institute of Statistics. On the whole, 105+ and 110+ subjects have to be considered very rare cohorts of particular interest for the study of both the ageing phenotype and the healthy ageing determinants. This means that 105+ and 110+ are most informative for ageing research, even if it is not yet known whether 105+ reach the last decades of their life according to a molecular trajectory which progresses at a normal rate of change or whether the attainment of this remarkable age results from a slower molecular ageing rate.
Relatively few studies have looked at epigenetic determinants of extreme longevity in humans. Here we test whether families with extreme longevity are epigenetically distinct from controls according to an epigenetic biomarker of ageing which is known as "epigenetic clock". We analyze the DNA methylation levels of peripheral blood mononuclear cells (PBMCs) from Italian families constituted of 82 semi-supercentenarians (mean age: 105.6), 63 semi-supercentenarians' offspring (mean age: 71.8), and 47 age-matched controls (mean age: 69.8). We demonstrate that the offspring of semi-supercentenarians have a lower epigenetic age than age-matched controls (age difference of 5.1 years) and that centenarians are younger (8.6 years) than expected based on their chronological age. Future studies will be needed to replicate these findings in different populations and to extend them to other tissues. Overall, our results suggest that epigenetic processes might play a role in extreme longevity and healthy human ageing.