Even if science can eliminate the main problems associated with aging, such as cancer and dementia, human life may still have a natural limit. According to one study, accumulated mutations in DNA are capable of setting a boundary for longevity.
Biological ceiling of longevity
Researchers from the Skolkovo Institute of Science and Technology in Russia calculated that this biological limit would be between 146 and 194 years in a hypothetical scenario free from age-related diseases.
Mutations as an obstacle to immortality
During life, cells undergo numerous division cycles. During this process, small errors can occur in the genetic material. Although the body is capable of correcting most of these errors, some changes remain and accumulate over time. These changes are called somatic mutations. Most of them do not cause serious consequences, but some can affect cell function and contribute to the development of problems such as cancer.
The team, led by computational biologist Dmitry Kriukov, developed a mathematical model to answer a specific question: do DNA mutations themselves limit human lifespan, excluding all other aging factors? The model gave a positive answer. The average expected lifespan in this scenario ranged from 146 to 194 years depending on the calculation used.
The researchers published their findings in the journal npj Aging, noting that this is an important step toward separating aging into quantitatively measurable components.
Differences in body tissues
The study also demonstrated that different tissues of the body react differently to the passage of years. Organs such as the skin and liver have a high capacity for renewal and can regularly replace old cells. In contrast, heart and brain cells remain in the body for a long time, accumulating genetic changes over decades, which may be one of the main limits identified by the model.
Key findings of the work included: somatic mutations naturally increase over the lifespan; some genetic changes impair cellular activity; cells that are not easily replaced accumulate more changes; and eliminating age-related diseases alone is insufficient to ensure unlimited life.
Unknown aspects of aging
The authors emphasize that DNA mutations are only part of the aging process. The theory of somatic mutations has been studied for decades, but its impact on the loss of bodily functions is still debated. Kriukov himself stresses that the result obtained is not a prediction of the age people will reach. He explained that it is a 'mathematical estimate (albeit cautious), not experimental data'. In the researcher's opinion, somatic mutations have a relatively limited impact when analyzed in isolation but may become more significant when combined with other mechanisms.
The work offers a method for separately measuring how different biological processes contribute to human aging, which will help guide new research in the field of longevity.
