CNIO researchers discover that telomere shortening rate predicts lifespan of species

A flamingo lives 40 years and a human being 90 years; a mouse lives two years and an elephant lives 60 years. Why? What determines the lifespan of a species? After analyzing nine species of mammals and birds, researchers at the Spanish National Center for Cancer Research (CNIO) have established a very clear relationship between the lifespan of these species and the rate of shortening of their telomeres , the structures protecting the chromosomes and the genes that they contain. . The relationship is expressed as a mathematical equation, a formula for accurately predicting the longevity of the species. The study was conducted in collaboration with the aquarium of the Madrid Zoo and the University of Barcelona.

"The rate of shortening telomeres is a powerful predictor of the life span of species," write the authors in a prestigious journal. Proceedings of the National Academy of Sciences (PNAS).

The study compares the telomeres of mice, goats, dolphins, gulls, reindeers, vultures, flamingos, elephants and humans, and reveals that species whose telomeres shorten more quickly have a life shorter.

The relationship can be adjusted to a certain type of mathematical curve, a power law curve, which, explain the authors PNAS, is also used to describe other processes such as population growth, size of cities, loss of species, body mass and individual income.

For Maria Blasco, head of the Telomere and Telomerase group of the CNIO and director of the study, the fact that there is such a clear relationship between the rate of shortening of telomeres and the life expectancy suggests that "we have found a universal pattern , a biological phenomenon that explains the life span of the species, and this deserves more research. "

What matters is not their length, but the speed at which they shorten

In the case of the relationship between shortening of telomeres and longevity of species, the curve found by CNIO researchers corresponds very well to the data. In fact, "the authors can use the equation to predict the life span of the species based solely on the rate of telomere shortening". The fit is best when we use the average life span of the species – 79 years in the case of humans – rather than the maximum life span – the 122 documented years lived by the French Jeanne Calment -.

It has long been known, largely thanks to the work of the Blasco group, that telomeres are the basis of aging. Telomeres are the ends of chromosomes, inside the nucleus of the cell; their function is to protect the genes. However, each time the cells multiply to repair the damage, their telomeres become a little shorter. Throughout life, telomeres may become too short and can not regenerate. When this happens, the cell stops working normally.

Until now, however, no relationship has been established between telomere length and the lifespan of each species. There are species with very long telomeres that have a short life and vice versa.

CNIO researchers have decided not to compare the absolute length of telomeres, but rather their speed of shortening. This is the first large-scale study comparing this highly variable parameter across species: human telomeres lose on average about 70 base pairs – the building blocks of genetic material – per year, while those of mice lose approximately 7,000 base pairs per year.

For Kurt Whittemore, the first author of the paper, this study confirms that telomeres play an important role in aging: "There are people who are not convinced, and they say for example that mice live two years and have very long telomeres, while much longer and have short telomeres, but we have shown that the important thing was not the initial length, but the rate of shortening and this parameter predicts the longevity of a species with a high degree of accuracy. "

Better predictor than size or heart rate

The measurements were carried out on blood samples taken from several individuals of nine species, mainly from the Zoo Aquarium of Madrid. The samples of Audouin's Gulls come from a wild colony of the Ebro Delta and were analyzed in collaboration with the University of Barcelona. The researchers measured in each species the telomeres of white blood cells of individuals of different ages.

In the Madrid Zoo Aquarium, the following species were studied: nine dolphins aged 8.6 to 50.1 years; 15 goats aged 0.8 to 10.1 years; eight reindeer from 1.4 to 10.5 years old; 15 flamingos aged 0.8 to 50.1 years; 6 vultures from 8.1 to 21.4 years old; four Sumatran elephants aged 6.1 to 24.7 years; Gulls aged 0 to 24 years; and 7 mice aged 1.4 to 2.6 years. The age of seagulls was determined from the rings with which they were banded when they were chicks, allowing the identification of individuals throughout their lives. In collaboration with the veterinary team of the Madrid Zoo Aquarium and in several species, such as elephants and dolphins, through a medical training to animals so that they collaborate voluntarily in examinations, blood samples were taken during their usual health monitoring.

The results indicate that the rate of telomere shortening predicts the longevity of species far better than other parameters considered so far, such as body weight – in general, smaller species tend to live faster or at a lower heart rate.

The authors of the study believe that one of the next steps to be taken is the study of very long-lived species, such as naked mole rats or bats.

In any case, "these results support the view that critical shortening of telomeres and the subsequent onset of damage to telomeric DNA and cellular senescence are a general factor in the lifespan of species", write authors PNAS.

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The study was funded by the Spanish Ministry of Science, Innovation and Universities, the Carlos III National Institute of Health, the Botín Foundation and the Banco Santander via the Santander Universities .

Reference Article: The rate of telomere shortening predicts the lifespan of species. Kurt Whittemore, Elsa Vera, Eva Martinez-Nevado, Carola Sanpera, Maria A. Blasco (PNAS, 2019). DOI: https: //www.PNAS.org /cgi /do I/ten.1073 /PNAS.1902452116

Video: https: //www.Youtube.com /watch? v =7J8h0972yEA