Nicotinamide riboside (NR), a compound that has been shown effective in boosting metabolism, can also induce muscular regeneration and enhance life span in mice, according to the study “NAD+ repletion improves mitochondrial and stem cell function and enhances life span in mice,” published in Science.
As we get older, the regenerative capacity of certain organs and muscles decreases due to the decline in stem cell function (senescence), which is required not only to maintain continuously proliferating tissues, such as the intestine or the skin, but also to regenerate quiescent tissues that suffered an injury, as in the case of the heart or the brain.
Under normal conditions, and in young organisms, stem cells react to the body signals and proliferate to regenerate damaged organs. “We demonstrated that fatigue in stem cells was one of the main causes of poor regeneration or even degeneration in certain tissues or organs,” Hongbo Zhang, the study’s first author, said in a press release.
One of the hallmarks of aging is the appearance of mitochondrial dysfunction. Now, a team of researchers at EPFL’s Laboratory of Integrated Systems Physiology (LISP), headed by Johan Auwerx, was able to identify a cellular component, NAD+, that was associated with the way mitochondria changed with age and affected stem cell function. Although mitochondria function had already been linked to metabolism, “we were able to show for the first time that their ability to function properly was important for stem cells,” Auwerx said.
“We gave nicotinamide riboside to 2-year-old mice, which is an advanced age for them,” the researcher said. “This substance, which is close to vitamin B3, is a precursor of NAD+, a molecule that plays a key role in mitochondrial activity. And our results are extremely promising: Muscular regeneration is much better in mice that received NR, and they lived longer than the mice that didn’t get it.”
This suggests that NR may have a therapeutic potential not only on aging, but also on other diseases, such as muscular dystrophy. Similar findings have also been described for brain and skin stem cells, when NR was used.
“This work could have very important implications in the field of regenerative medicine,” Auwerx said. “We are not talking about introducing foreign substances into the body but rather restoring the body’s ability to repair itself with a product that can be taken with food.”