Nicotinamide Deficiency In Primary Open-Angle Glaucoma

PURPOSE: To investigate the plasma concentration of nicotinamidein primary open-angle glaucoma (POAG). DESIGN: Case-control study. METHODS: Plasma of 34 POAG individuals were compared to that of 30 age- and sex-matched controls using a semi-quantitative method based on liquid chromatography coupled to high- resolution mass spectrometry. Subsequently, an independent quantitative method, based on liquid chromatography coupled to mass spectrometry, was used to assess nicotinamideconcentration in the plasma from the same initial cohortand from a replicative cohortof 20 POAG individuals and 15 controls. RESULTS: Using the semi-quantitative method, the plasma nicotinamideconcentration was significantly lower in the initial cohortof POAG individuals compared to controls (-36 %, False Discovery Ratecorrected p-value = 0.0027) and further confirmed in the same cohort, using the targeted quantitative method, with mean concentrations of 0.14 micromolar (median: 0.12 micromolar; range: 0.06-0.28 micromolar) in the POAG group (-30 %; p = 0.022), and 0.19 micromolar (median: 0.18 micromolar; range: 0.08-0.47 micromolar) in the control group. The quantitative dosage also disclosed a significantly lower plasma nicotinamideconcentration (-33 %; p = 0.011) in the replicative cohortwith mean concentrations of 0.14 micromolar (median: 0.14 micromolar; range: 0.09-0.25 micromolar) in the POAG group, and 0.19 micromolar (median: 0.21 micromolar; range: 0.09-0.26 micromolar) in the control group. CONCLUSIONS: Glaucoma is associated with lower plasmatic nicotinamidelevels, compared to controls, suggesting that nicotinamidesupplementation might become a future therapeutic strategy. Further studies are needed, in larger cohorts, to confirm these preliminary findings.