Chinese scientists have made a discovery that could change our understanding of the factors that influence longevity. They found that bile acids produced by the liver, specifically lithocholic acid (LCA), have effects similar to caloric restriction, a commonly accepted method that improves life expectancy.
They found that LCA, which is produced by the liver, can enhance muscle regeneration, as well as increase grip strength and running ability.
Previous studies have shown that mammals accumulate LCA during caloric restriction, and it activates a key molecule involved in metabolism, called AMP-activated protein kinase, or AMPK. It is activated when glucose levels drop, plays a key role in aging, as it regulates processes such as inflammation and nerve degeneration.
In experiments with fruit flies, the scientists found that LCA activates AMPK and causes anti-aging effects similar to caloric restriction. Since these animals do not synthesize LCA naturally, scientists injected it into them. Depriving the animals of the ability to produce AMPK resulted in the loss of the effects of LCA when administered, confirming that the liver acid acted in an “AMPK-dependent manner”.
The scientists took blood serum from mice that had been calorie restricted for four months and injected it into rodents that were fed a normal diet. They found that the injected serum led to the activation of AMPK in the liver and muscles of the mice.
The researchers also observed that the administration of LCA increased the average lifespan of the flies by four to five days.
The introduction of "only the activated LCA metabolite can have an antiaging effect," the scientists concluded in the study.
"People have been looking for the elixir of longevity for a long time. "LCA is one possibility because it is a single molecule in the blood of people practicing calorie restriction and activates AMPK, which in turn further causes changes in blood metabolites," commented lead study author Lin Shencai of Xiamen University.
