Nicotinamide riboside may successfully prevent noise-induced hearing loss

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Nicotinamide riboside (NR), a precursor to vitamin B3, may be able to help prevent noise-induced hearing loss (NIHL) based on results of a new study in mice. The study, published in December in the journal Cell Metabolism was conducted by researchers in otolaryngology, head and neck surgery, and pharmacology at Cornell University - New York, the University of California - San Francisco, and the University of North Carolina. They administered nicotinamide riboside (NR), a recently described NAD+ precursor, to WldS mice overexpressing an NAD+ biosynthetic enzyme (SIRT3) before or after exposure to loud noise. NAD+ is known to exhibit axon-protective effects in cultured neurons.

The study found that NR prevented damage to synaptic connections, prevented both short-term and long-term hearing loss, and was equally effective whether given before or after noise exposure. “This discovery identifies a unique pathway and a potential drug therapy to treat noise-induced hearing loss,” says Dr Kevin Brown, lead author on the paper. Contributing author Dr Samie Jaffrey, professor of pharmacology at Cornell, adds that NR has the advantage of being absorbed orally and reaching cells readily. “It has all the properties that you would expect in a medicine that could be administered to people.”

According to the researchers, the substance may also be beneficial for other age-related conditions. This hypothesis is related to the way in which NR protects nerve cells by increasing the activity of SIRT3. Other studies have shown that aging results in decreased levels of SIRT3.

Source: Brown KD, et al. Activation of SIRT3 by the NAD+ Precursor Nicotinamide Riboside Protects from Noise-Induced Hearing Loss. Cell Metabolism 20, 1059-1068, December 2, 2014; Underground healthreporter.

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