A Study Of Influential Factors On The Endothelium Function Of Great Saphenous Vein Bypass

Objective :This study was divided into four parts:1) To observe the effect of endothelium function on the proximal and distal of great saphenous vein;2) To observe the effect of smoking on the endothelium function of great saphenous vein.3) To observe the effect of type 2 diabetes (T2MD)on the endothelium function of great saphenous vein.4) To observe the effect of tetrahydrobiopterin (BH4) on endothelium function of the great saphenous vein from smoker.Methods:1)The distal and proximal of great saphenous vein rings in 3mm long selected from 36 patients with coronary artery bypass grafting(CABG),The change of the tone was measured in organ chamber when phenylephrine,norepinephrine,acetylcholine and nitroglycerin in different concentrations (10-9~10-5mol/L) were added into the organ chamber.2) The rings of great saphenous vein in 3mm long of selected from 31 patients with coronary artery bypass grafting:which including smoking over 10 years(n=12),ex-smoking over 1 years(n=9) and non-smoking(n=10). The changes of the tone were measured in organ chamber when vasoconstriction induced by phenylephrine(10-5mol/L) , then vasodilatation induced by acetylcholine (10-9~10-5mol/L) or nitroglycerin (10-9~10-4mol/L). Then check the morphological changes of vascular endothelium for every group.3)Selected 40 patients under coronary artery bypass grafting, include 20 patients with coronary artery disease complicating type 2 diabetes and 20 patients only with coronary artery disease. The rings of great saphenous vein in 1cm long were selected from every patient. The changes of tone were measured in organ chamber when vasoconstriction induced by phenylephrine (10-5mol/L) then vasodilatation induced by ACh or NTG. And check the morphological changes of vascular endothelial for every group.4)The rings of great saphenous vein selected from 22 patients with CABG, which including smoking(n=12)and non-smoking (n=10) patients. After incubated in Krebs-Henseleit (KH) plus BH4 (20μmol/L) or N-nitro-L-arginine (L-NNA, 0.1mol/L), the vasoconstriction and vasodilatation were induced by phenylephrine (10-5 mol/L) and non-receptor-mediated calcium ionophore (A23187,10-9~10-5 mol/L) separately in organ chamber. And check the change of ultra-structure of endothelium in every group.Results:1) Vasoconstriction induced by PE or NE and vasodilatation induced by ACh or NTG was no significant difference between distal and proximal of GSV(P>0.05).2) Vasoconstriction induced by PE and non-endothelium-dependent vasodilatation induced by NTG was no significant difference between smoking,ex-smoking or non-smoking patients. And endothelium-dependent vasodilatation induced by ACh in smoking was significantly decrease than in ex-smoking and non-smoking(P<0.05),while there was no significant difference between ex-smoking and non-smoking(P>0.05). The morphological of endothelium observed in smoking group was more susceptible to necrosis, non-continuous, hypertrophy and hyperplasia in vascular intimal, cavity formation under endometrial pathology.3) Compare with non-T2DM group , vasoconstriction induced by phenylephrine and vasodilatation by nitroglycerin was no significant difference in T2DM group (P>0.05).But vasodilatation induced by Ach was significantly decreased in T2DM group(P<0.01). And the morphological of endothelial damage was easy to find.4) Vasodilatation induced by A23187 significantly increased in rings of smoker incubated in KHS plus BH4 than in KHS(P<0.05), while there was no significant difference between increased in rings of smoker incubated in KHS plus BH4 and non-smoking group(P>0.05). And there was none obvious ultrastructural damage of endothelial cells incubated by KHS plus BH4.Conclusion:1) The response of proximal and distal great saphenous vein to clinical vasoconstrictor drugs is similar, while endothelium-dependent and non-endothelium-dependent relaxations induced by vasodilator are also no significant difference.2) Smoking has a deleterious effect on the endothelial function of great saphenous vein, however, smoking cessation over 1 year may help to restore the endothelial function impaired by smoking.3) Type 2 diabetes can aggravate the damage of saphenous vein endothelial cell in coronary artery disease.4) Smoking impairs the relaxation function mediated by endothelium-derived nitric oxide in great saphenous, which may be restored by BH4.