title: Nitric oxide production and endothelium-dependent vasorelaxation ameliorated by N1-methylnicotinamide in human blood vessels.
abstract: N(1)-methylnicotinamide (MNA(+)) has until recently been thought to be a biologically inactive product of nicotinamide metabolism in the pyridine nucleotides pathway. However, the latest observations imply that MNA(+) may exert antithrombotic and anti-inflammatory effects through direct action on the endothelium. We examined both in vivo and in vitro whether the compound might induce vasorelaxation in human blood vessels through the improvement of nitric oxide (NO) bioavailability and a reduction of oxidative stress mediated by endothelial NO synthase (eNOS) function. MNA(+) treatment (100 mg/m(2) orally) in healthy normocholesterolemic and hypercholesterolemic subjects increased the l-arginine (l-NMMA)-inhibitable flow-mediated dilation (FMD) of brachial artery responses that also positively correlated with MNA(+) plasma concentrations (r=0.73 for normocholesterolemics and r=0.78 for hypercholesterolemics; P<0.0001). MNA(+) increased FMD at the same concentration range at which it enhanced NO release from cultured human endothelial cells after stimulation with either the receptor-dependent (acetylcholine) or the receptor-independent endothelial NO synthase agonists (calcium ionophore A23187). MNA(+) restored the endothelial NO synthase agonist-stimulated NO release after the exposure of the cells to oxidized low-density lipoprotein. This effect was also associated with the normalization of the [NO]/[superoxide] balance in the endothelial cells. Taken together, the increased NO bioavailability in the endothelium contributes to the vasorelaxating properties of MNA(+). Targeting eNOS with MNA(+) might be therapeutically relevant for functional disorders of the endothelium, such as hypercholesterolemia and atherosclerosis.
authors.affiliation: Department of Medical Biochemistry, Jagiellonian University Medical School, Krakow, Poland.
authors.forename: Teresa B
authors.initials: TB
authors.lastname: Domagala
authors.forename: Agata
authors.initials: A
authors.lastname: Szeffler
authors.forename: Lawrence W
authors.initials: LW
authors.lastname: Dobrucki
authors.forename: Jerzy
authors.initials: J
authors.lastname: Dropinski
authors.forename: Stanisław
authors.initials: S
authors.lastname: Polanski
authors.forename: Magdalena
authors.initials: M
authors.lastname: Leszczynska-Wiloch
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Kotula-Horowitz
authors.forename: Jacek
authors.initials: J
authors.lastname: Wojciechowski
authors.forename: Leszek
authors.initials: L
authors.lastname: Wojnowski
authors.forename: Andrzej
authors.initials: A
authors.lastname: Szczeklik
authors.forename: Leszek
authors.initials: L
authors.lastname: Kalinowski
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000328:Adult; D001916:Brachial Artery / Q000187:drug effects* / Q000502:physiology*; D000001:Calcimycin / Q000494:pharmacology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D006801:Humans; D006937:Hypercholesterolemia / Q000503:physiopathology; D066298:In Vitro Techniques; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D010100:Oxygen / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology
chemical_list: D009536:Niacinamide; D009569:Nitric Oxide; D000001:Calcimycin; D052250:Nitric Oxide Synthase Type III; D000109:Acetylcholine; D010100:Oxygen; C008472:N-methylnicotinamide