Nicotinamide does not influence cytokines or exhaled NO in human experimental endotoxaemia

This study examined the hypothesis that nicotinamide could attenuate endotoxin-induced inflammatory responses in humans as indicated by levels of cytokines and nitric oxide. Ten healthy male volunteers participated in a randomised, double-blind, cross-over design with regard to the effects of nicotinamide. The volunteers received orally 4 g nicotinamide or placebo at 14 h and at 2 h preceding the experiment (total dose of 8 g). Endotoxin (E. coli, 2 ng/kg), was administered intravenously. Blood samples and haemodynamic data were collected prior to and up to 6 h after the endotoxin infusion. Orally exhaled NO was measured hourly. Following endotoxin, body temperature increased from baseline 36.3 +/- 0.09 degrees C to a maximum of 38.0 +/- 0.1 degrees C for all (mean +/- SEM, P < 0.001) and heart rate increased from 59 +/- 1.9 to 87.0 +/- 2.6 beats/min after 3 h (mean +/- SEM, P < 0.001). Endotoxin challenge also markedly elevated the TNF-alpha, IL-6, IL-8 and IL-10 concentrations (P < 0.001 versus baseline for all) during the study period. Orally exhaled NO also increased (P < 0.01) compared to baseline. Nicotinamide treatment did not influence the patterns of cytokine and NO response to endotoxin. In conclusion, there was no effect on the inflammatory parameters by oral nicotinamide at a dose of 8 g, limiting the potential use of this agent for anti-inflammatory purpose in man.