Why are bears obese but healthy? Scientists solve the mystery of animal ‘superpower’

Western media said that some animals have “superpower”, they accumulate fat in the body, and can hibernate for months without health problems. The scientific community wants to solve the mystery of the animal’s “superpower” and apply it to medicine. Elephants have a life expectancy close to humans, but are almost as likely to develop cancer, The Spanish newspaper El Pais reported on November 29. In 2015, a team at the University of Utah in the United States found the reason that elephants had an additional 38 copies of genes that synthesize the tumor-suppressing p53 protein.

In addition, the mechanism by which damaged cells at risk of cancer are removed from the cycle is much more efficient than in humans. Dolphins have a special protection against the formation of blood clots, which are a major threat to human health.

Christopher Gregg and Elliot Ferris, researchers at the University of Utah, are tracking the genomes of several mammals to find the key to these “superpowers,” the report said. They published an article in the journal Cell Reports on June 26 to explore why hibernating animals such as bears do not have problems with obesity or insulin resistance.

Why are bears obese but healthy? Scientists solve the mystery of animal 'superpower'

They analyzed four species that went to sleep at some point in the year: pony island rafter, 13-striped ground squirrel, small-mouthed lemur and small brown manta. These animals can make some changes during several months of sleep, such as a sharp drop in heart rate and respiratory rate. Squirrels had their heart rate reduced from 200 beats per minute to about five times, and their breathing rate was reduced from more than 100 beats per minute to one every 5 minutes. It does not require eating, urination, and defecation during hibernation.

In order to hibernate smoothly, individuals of these species need to eat to accumulate storage for the previous few months, but somehow they become obese and produce insulin resistance while remaining healthy, the report said. If a person does this all year round, they will end up with diabetes, high blood pressure and many other diseases.

The study authors compared the genomes of the four species with the genomes of healthy humans and the genes associated with “little fat Willie syndrome”, a disease that causes appetite hyperactivity and pathological obesity, to identify a large number of areas of the animal genome that approximate human obesity-related genes. This allows you to turn off some of the factors that control the genes associated with obesity. A total of 364 genetic factors associated with regulating hibernation and obesity were found.

At present, large-scale studies of such genomes have not been directly applied to human health, the report said. Scientists first tried to understand how the genomic common altogether behind obesity or metabolic problems played a role in different animals in the evolution to better adapt to the environment. In some cases and when animals enter different periods, this adaptation means increasing the ability to sleep for months.

For bears, this healthy regulation of obesity allows them to survive in winter, and for lemurs, the only primates that need to hibernate, this temporary suspension of activity allows them to survive the dry season in Madagascar.

However, in addition to obtaining basic information about certain biological mechanisms, Greg and his collaborators are also considering how to apply this knowledge. “By understanding the genomic fragments that affect obesity or metabolic syndrome, we can assess a person’s risk of developing these diseases throughout their lives from their genetic sequences,” he said. In this way, we can help people adjust their lifestyle to their own situation, and in the future to develop drug therapies to treat obese people. (Compilation/Li Zijian)

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