Vitamin B3 modulates mitochondrial vulnerability and prevents glaucoma in aged mice

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Science  17 Feb 2017:
Vol. 355, Issue 6326, pp. 756-760
DOI: 10.1126/science.aal0092

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  • Oral vitamin B3 for glaucoma management: the beginning of a new era?
    • Jose Javier Garcia-Medina, Ophthalmologist and Associate Professor, General University Hospital Reina Sofia, Murcia, and Department of Ophthalmology and Optometry, University of Murcia, Spain.
    • Other Contributors:
      • Monica del-Rio-Vellosillo, Anesthesiologist, University Hospital La Arrixaca, Murcia, Spain
      • Vicente Zanon-Moreno, Associate Professor, Department of Preventive Medicine and Public Health, School of Medicine, University of Valencia, Spain
      • Maria Dolores Pinazo-Duran, Ophthalmologist and Associate Professor, University Hospital Doctor Peset, Valencia, and Department of Ophthalmology, University of Valencia, Spain

    In their report “Vitamin B3 modulates mitochondrial vulnerability and prevents glaucoma in aged mice” (16 February, p.756), P.A. Williams et al. exquisitely demonstrated the prophylactic and therapeutic effects of vitamin B3 (nicotinamide) on a murine glaucoma model. However, the influence of this vitamin on glaucoma has been previously investigated in humans. In two population studies the authors concluded that the dietary intake levels of vitamin B3, even higher than the recommended dietary allowances for adults, which are 14-16 mg/day (1), were not related to an increased or decreased risk of having glaucoma (2,3). Plus, glaucoma patients who were supplemented for 2 years with oral multivitamin complexes that contained 18mg/day of vitamin B3 (apart from dietary intake) did not show any clinical advantage compared to glaucomatous controls in a recent trial run by our group (4).
    The disparity in the results of human studies and the study by P.A. Williams et al. in mice may be related to the administered dose. Those authors used 550 and 2,000 mg/kg of body weight per day in mice, and found the most effective results with the latter. These megadoses are the equivalent to 3,341.25 mg/day and 12,150 mg/day in a 75-Kg human, respectively (5), which exceeds 3,000 mg/day, considered the safe upper limit for oral nicotinamide supplementation (6). Hence these results cannot be directly extrapolated to humans and the equivalent dose in future clinical studies should lower. We...

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    Competing Interests: None declared.