Effect of liposomal nicotinamide adenine dinucleotide (NAD+) on NAD+/NADH levels in Caco-2 enterocytes. Caco-2 cells growing as monolayers in six-well chambers were incubated for 24 hours under cytokine-free conditions alone (Control) or with cytomix in the presence or absence of free NAD+ (NAD), of empty liposomes (Lipo), or of NAD+-containing liposomes (LipoNAD). Results are means ± SEM (n = 4 per condition). Data were analyzed by analysis of variance followed by Duncan's multiple range test. *P < 0.05 versus control, †P < 0.05 versus Cyto. Reprinted from  with permission.