Dysfunctional Endothelial Nitric Oxide Biosynthesis in Healthy Smokers With Impaired Endothelium-Dependent Vasodilatation

Abstract

Background-The mechanisms involved in the dysfunction of both endothelium-dependent vasodilatation (EDV) and NO biosynthesis related to smoking are unclear. In this study, EDV was assessed in healthy smokers and nonsmokers in vivo and, using serum from the same individuals, was related to the NO biosynthetic pathway in vitro. Methods and Results-Flow-mediated EDV of the brachial artery was measured in 23 male patients (8 nonsmokers and 15 smokers). Serum was collected, added to confluent (Ϸ85%) monolayers of human umbilical vein endothelial cells (HUVECs), and incubated for 12 hours. Basal and substance P-stimulated NO production was measured. The HUVECs used for measuring basal NO production were lysed, and both endothelial NO synthase (eNOS) protein expression and eNOS activity were determined. EDV was lower in smokers compared with nonsmokers (PϽ0.001). HUVECs treated with serum from smokers compared with nonsmokers showed significantly lower basal (PϽ0.0001) and stimulated (PϽ0.02) NO production, higher eNOS expression (PϽ0.0001), but lower eNOS activity (PϽ0.004). There was a significant positive correlation between in vivo EDV and in vitro substance P-stimulated NO production (rhoϭ0.57, PϽ0.01) and between basal NO production and eNOS activity (rϭ0.54, PϽ0.008) and a negative correlation between basal NO production and eNOS protein expression (rϭϪ0.60, PϽ0.003). Conclusions-This is the first study to combine an in vivo model with a near-physiological in vitro model to demonstrate an association between decreased NO production and reduced EDV. Cigarette smoking was associated with reduced EDV, NO generation, and eNOS activity in the presence of increased eNOS protein expression.

Endothelial nitric oxide synthase gene polymorphisms in patients with nontraumatic femoral head osteonecrosis

“…It was reported that smoking decreases activity of eNOS and may modify the relationship between polymorphisms and expression levels. 20,21 For that reason, we performed multiple binary regression analysis (Table 4). Although smoking was a more powerful risk factor than 27-bp repeat polymorphism in total FHON patients, 4a allele was the only variable with statistical significance after adjustment of the effect of smoking in idiopathic group (p c ¼ 0.026, OR 4.302, 95% CI 1.359-13.621).…”

“…We also observed that there was more smoker and higher exposure to smoking in FHON patients compared to controls. It was previously reported that smoking reduces the function of eNOS 20,37,38 and is a potential risk factor of the development of FHON and LeggCalve-Perthes disease. 8,18,24,[39][40][41] The results previous studies are compatible with our speculation.…”

C-reactive protein is associated with cigarette smoking-induced hyperfiltration and proteinuria in an apparently healthy population

“…[37][38][39] However, the majority of in vitro data has involved the use of cigarette smoke extract solution, which is probably not an appropriate physiological model, as circulating particulate of cigarette smoke has to first bypass the lung. 40 Thus, the effect of smoking on the NO pathway seems to be more complex on a cellular level than suggested by the described Abbreviations: ALT, alanine transaminase; ANOVA, analysis of variance; AST, aspartate aminotransferase; BMI, body mass index; BP, blood pressure; CRP, C-reactive protein; eGFR, estimated glomerular filtration rate; g-GTP, g-glutamyl transpeptidase; HbA1c, hemoglobin A1c; HDL-c, high-density lipoprotein-cholesterol; HOMA, homeostatic model assessment; LDL-c, low-density lipoprotein-cholesterol; NS, nonsignificant. Data are shown as mean ± s.e.…”

Smoking, Metalloproteinases, and Vascular Disease

“…25 Human endothelial cells exposed to sera from smokers have decreased nitric oxide availability despite increased nitric oxide synthase expression, with scavenging of nitric oxide by increased reactive oxygen species generation. 26,27 Smokingassociated endothelial dysfunction can be ameliorated by 3-hydroxy-3-methylglutaryl (HMG)-coenzyme A (CoA) reductase inhibitor therapy independently of changes in lipid levels, 28 by supplementation with tetrahydrobiopterin, 26 and by xanthine oxidase inhibition with allopurinol. 29 Monocytes isolated from smokers demonstrate increased adherence to endothelial cells, which is corrected by vitamin C therapy.…”