A team of researchers from the University of Southern California (USC) recently published a paper in the journal Aging describing the role of a mitochondrial peptide molecule called humanin in regulating life. “Humanin has long been known to prevent many aging-related diseases. But this is the first time we know that it can extend life. Professor Pinchas Cohen, who led the study, said.
Although the name carries “human” in the name, humanin is not only present in human mitochondria. In fact, the presence of such molecules in mitochondria throughout the animal kingdom suggests that they may be somewhat conservative in evolution. To understand the role of humanin, the researchers examined human levels in humans and in a variety of animal models.
In the past, it has been found that in many animal species, human levels decline as they age. The study suggests that in many older animals, humanin levels remain at a high level. For example, naked molerats, who look strange but live very long, have a very slow decline in humanin levels during their nearly 30-year-old “rat life”. In contrast, mice lost 40% of humanin in the 18 months of life! Primate animals, such as rhesus monkeys, also have significantly lower levels of humanin in their bodies between the ages of 19 and 25.
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Interestingly, the researchers found the children of 18 centenarians and compared them to the offspring of 19 other non-centenarians. The comparison found that the former’s human level could indeed be maintained at a very high level. And they do live longer.
Providehuman to extend the life of nematodes
So what happens when human levels are artificially increased? The scientists did a test in the online worm. They found that increasing the expression of humanin was enough to extend the life of nematodes. In mice, the additional humanin improved their metabolism overall, although they did not significantly extend their life span. And whether nematodes or mice, they become thinner.
While humanin appears to extend life and improve health, it’s not without its costs — these long-lived nematodes have fewer offspring, the researchers said in an official press release. In the past, scientists have observed similar phenomena in long-lived humans, the paper notes.
“The balance between longevity and reproduction may be evolutionaryly conservative. It depends on whether we want to use energy to breed more offspring, or whether we use energy to maintain the health of individuals for possible future reproduction. Evolutionaryly, the purpose of life is to reproduce. If you can’t reproduce for a while, you should live as long as possible. And the ‘side effect’ is longevity. Professor Kelvin Yen, the first author of the study, said.