Useful radicals
Scientists have discovered an unusual life extension factor
In experiments on worms, scientists have found that individuals who have experienced oxidative stress at an early age become more resilient and live longer. The results of the study are published in the journal Nature (Bazopoulou et al., Developmental ROS individualizes organizational stress resistance and lifespan – VM).
Oxidative stress – the process of cell damage as a result of oxidation – is the main cause of aging of organisms. It can also occur with excessive physical exertion or fasting. In humans, oxidative stress is the cause or an important component of many serious diseases, such as atherosclerosis, hypertension, Alzheimer's disease, diabetes, infertility, chronic fatigue syndrome.
Oxidative stress occurs when cells produce too many oxidants and free radicals, as a result of which such important components of the cell itself as lipids and DNA begin to oxidize.
American scientists from the University of Michigan, studying the roundworm Caenorhabditis elegans, found that worms that produced more oxidants at the beginning of their lives lived longer than worms that produced fewer reactive oxygen species.
Traditionally, it is believed that the two main factors determining life expectancy are genetics, that is, good heredity, and environmental conditions. A study by Michigan scientists suggests that there are, apparently, other factors on which longevity depends.
C. elegans worms are used as a model to study aging, firstly because they are very short-lived, and secondly because each hermaphrodite mother produces hundreds of genetically identical offspring.
Despite the complete genetic identity, the researchers found that the life expectancy of worms kept in the same conditions differed significantly.
"If life expectancy were determined solely by genes and the environment, we would observe that genetically identical worms grown in the same Petri dish would die at about the same time, but this is not what happens at all. Some worms live for only three days, while others are still happily moving after 20 days, – the words of the head of the study Ursula Jakob are quoted in a university press release. "Then the question arises, what besides genetics and the environment causes such a big difference in life expectancy?"
The authors found that animals with different lifespans differed significantly in the amount of reactive oxygen species (ROS) they produced at the beginning of life. And, surprisingly, instead of dying earlier, the worms that produced more ROS lived longer.
To confirm their observations, scientists exposed the entire worm population to ROS, and the average life expectancy of the entire population increased.
Although the researchers do not yet know what causes oxidative stress in worms, they were able to determine which processes resulted in increased life expectancy. The increased production of ROS in young animals caused changes in histones, an extensive class of proteins involved in the packaging of DNA strands and the processes of its repair in case of damage.
It is known that a histone modifier sensitive to oxidative stress is also present in mammalian cells. And the result has already been tested on mice. It is quite possible that early oxidative stress is beneficial to the cells of any organisms, including humans. Understanding this will help scientists develop intervention techniques at the early stages of the development of organisms that contribute to prolonging life in old age.
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