Let us live. nematodes survive longer when exposed to a product of metabolism.
King James Holmes / Science Source
Every day our cells produce small amounts of a molecule which, in higher doses, could be the key to lead a longer and healthier life. A team of researchers has discovered that this molecule increases the lifespan of worms over 50%, raising the possibility that it will increase human longevity.
"I think the data is really compelling," says molecular geneticist William Mair of the Harvard School of Public Health in Boston. "They have a strong effect of lifetime use the [compound]."
The way a long life does not lead through the kitchen. Researchers have known for decades that when animals eat considerably less than undergo what is known as caloric restriction or dietary restriction they live longer and delay or prevent age-related problems such as cardiovascular disease and diabetes. But if you intend to try at home, there are a few catches. On the one hand, scientists have not confirmed the benefits of calorie restriction in primates, including humans. While eating less helps monkeys age, it is difficult to know whether calorie restriction increases their lifespan. And survive on far fewer calories is no picnic. "The problem is that this requirement is so strict that almost no one can do it," says Jing Huang of the University of California, Los Angeles.
Therefore, the researchers tested other ways to slow aging and prolong life, such as resveratrol grape extract and immunosuppressive drug rapamycin. Although both have shown promise in experimental animals rapamycin increases the life of middle-aged mice-they've disadvantages also represented. Rapamycin, e.g., blends sugar metabolism and can lead to diabetes. Huang and his colleagues concluded that because aging depends on the metabolism, the compounds produced in the cells by metabolic reactions known as metabolites, may also increase the lifetime.
The researchers tested their idea on nematodes, worms long millimeter commonly used in longevity studies. They hit the jackpot with the first molecule they tried, α-ketoglutarate (α-KG), an intermediate in a metabolic cycle that helps a cell extract energy from food. When the researchers added the compound to the culture dishes worms, the animals survived up to 70% longer than normal, the team announced today online Nature . Animals transported about 50% of α-KG in their cells than to witnesses. As caloric restriction, the α-KG supplement postponed the physical deterioration of worms.
To understand how α-KG works, Huang and his colleagues used a technique they developed that identifies proteins in human cells that interacts with a-KG. The results showed that the compound binds to the ATP synthase, an enzyme that makes ATP, main carrier molecule of the cell's energy. ATP synthase lies in the power generation structures called mitochondria. By studying the mitochondria of cow heart cells, the researchers found that the α-KG blocks ATP synthase, turning down the metabolism of the cell.
When the researchers tracked more cellular effects of α-KG, they discovered that indirectly inhibits a protein called TOR which measures the supply of nutrients and scientists suspect, to determine how speed we age. Alpha-KG "can be an inner fountain of youth, if you like, which can be adjusted to counteract aging," says Huang. Caloric restriction causes side effects in animals such as reduced reproduction, but researchers not see these problems in the worms that ate α-KG.
mitochondrial biochemist Michael Ristow of the Swiss federal Institute of technology in Zurich said that the molecular mechanism of this effect took him by surprise. He noted that d other studies have shown that calorie restriction increases the synthesis of ATP by making more efficient mitochondria, so you had predicted that α-KG would do the same. "that's what makes it interesting," he said. "It is unexpected."
Dietary supplements that contain α-KG and supposedly strengthen the muscles are already on the market. The study drops a barbell on their use, however, suggesting that α-KG inhibits TOR, thus counteracting muscle growth. "If people take this as a muscle builder, one might think that this does not cause the desired effect," says Mair.
There is no guarantee that α-KG will have the same effects on aging in people that's in worms. and before researchers can not even answer that question, they will need to determine if the compound also extends the life of laboratory organisms such as flies and mice. However, Mair said, researchers have long hoped to identify small molecules that slow human aging and the study "is the next step towards this goal."
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