title: N-acetylcysteine does not improve the endothelial and smooth muscle function in the human saphenous vein.
abstract: Oxidative stress can lead to vein graft dysfunction in the saphenous vein. This ex vivo study is aimed to compare the effects of increasing concentrations of the antioxidant N-acetylcysteine (NAC) with heparinized saline (HS) on endothelial and smooth muscle function in the human saphenous vein. Long saphenous vein segment obtained during infrainguinal bypass surgery was divided into 7 rings; 1 immersed in HS and the remaining 6 in increasing NAC concentrations (0.0025%, 0.005%, 0.01%, 0.02%, 0.03%, and 0.04%). Rings were mounted in an organ bath, and relaxant responses to acetylcholine and sodium nitroprusside were assessed through isometric tension studies. Endothelium-dependent relaxations were observed in 77 vein segments from 11 patients. No significant difference was seen in veins treated with either lower NAC concentrations (0.0025%, 0.005%, 0.01%, 0.02%, and 0.03%) or HS. However, HS-treated veins showed significantly better relaxation compared to those treated with maximum (0.04%) NAC (P < .05). Endothelium-independent relaxations were observed in 91 segments from 13 patients. No difference in relaxation was observed between veins treated with HS or any of the NAC concentrations. In conclusion, lower NAC concentrations do not offer better endothelial protection than HS, whereas the highest NAC concentration has a detrimental effect on endothelium-dependent relaxation. Moreover, NAC did not show beneficial effect on direct smooth muscle relaxation.
authors.affiliation: Department of Vascular and Endovascular Surgery, Belfast City Hospital, Belfast, Northern Ireland, UK. aneessharif@yahoo.co.uk
authors.forename: Muhammad Anees
authors.initials: MA
authors.lastname: Sharif
authors.forename: Ulvi
authors.initials: U
authors.lastname: Bayraktutan
authors.forename: Ian Stuart
authors.initials: IS
authors.lastname: Young
authors.forename: Chee Voon
authors.initials: CV
authors.lastname: Soong
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology*; D000368:Aged; D000369:Aged, 80 and over; D004730:Endothelium, Vascular / Q000187:drug effects*; D005260:Female; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009130:Muscle, Smooth / Q000187:drug effects*; D009599:Nitroprusside / Q000494:pharmacology; D012501:Saphenous Vein
chemical_list: D016166:Free Radical Scavengers; D009599:Nitroprusside; D000111:Acetylcysteine