Effect of tetrahydrobiopterin on endothelium function of the great saphenous vein from smokers

Abstract

Objective To observe the effect of tetrahydrobiopterin ( BH4 ) on endothelium function of the great saphenous vein from smokers. Methods The rings of great saphenous vein were selected from 22 patients with coronary artery bypass grafting, which including smoking (experimental group,n = 12) and non-smoking (control group,n = 10) patients. After incubation in Krebs-Henseleit (KH), KH plus BH4 (20 μ mol/L) or N-nitro-L-arginine ( L-NNA, 0. 1 mol/L), the vasoconstriction and vasodilatation were induced by phenylephrine (1 × 10-5 mol/L) and non-receptor-mediated calcium ionophore (A23187,1 × 10-9-1 × 10 -5 mol/L) separately in an organ chamber. Results The maximum constriction in all groups had no significant difference ( P ＞ 0. 05 ). The maximum relaxation was significantly decreased in experimental group as compared with control group [(29.50 ± 6. 22 ) % vs (48.20 ± 7. 74 ) %, P ＜ 0. 01]after incubation in KH, while there was no significant difference (P ＞ 0. 05 ) after incubation in KH plus L-NNA [(24.50±5.72)% vs (28.8 ±5.64)%] or BH4[(46.40 ±6.32)% vs (50.80±6.91)%].Conclusion Smoking impairs the relaxation function mediated by endothelium-derived nitric oxide in great saphenous, which may be restored by BH4. Key words: Smoking; Great saphenous vein; Endothelium function; CABG