Abstract 16108: Smoking-Induced Vascular Damage is Associated With Decreased Circulating MicroRNA-126 and Pesistent Elevation of Plasma Serotonin
Background: Cigarette smoking induces deleterious vascular damages. Serotonin released to plasma upon platelet activation modulates vascular tonus and thrombus formation. The aim of this study is to investigate the smoking-related vascular damage and plasma serotonin level before and after smoking cessation.
Methods: In study 1, clinical profiles including endothelial function were compared between apparently healthy male smokers (n=27, 40±8 years) and age-adjusted non-smokers (n=21, 40±7 years). In study 2, smokers were instructed to stop smoking and clinical profiles and laboratory findings including endothelium-enriched microRNA-126 (miR-126) were investigated before and after 8 weeks of smoking cessation. Serotonin levels in platelet poor plasma were measured by HPLC. Endothelial function was assessed by 2 distinct techniques, namely flow-mediated dilation (FMD) using ultrasound and peripheral arterial tonometry (PAT) using End-PAT 2000. The expression of miR-126 was analyzed by quantitative real-time PCR.
Results: In Study 1, plasma levels of serotonin and serotonin corrected by platelets number (serotonin/plt) in smokers were higher than those in non-smokers (6.90±2.91 vs 4.60±2.32 nmol/L, P<0.01; and 31.3±16.6 vs 20.6±11.9x10-9 pmol/plt, P<0.05; respectively), and FMD in smokers was lower than that in non-smokers (3.12±1.15 vs 4.11±1.93 %, P<0.05). In study 2, serum level of cotinine, principal metabolite of nicotine, inversely correlated with HDL-C (P<0.05), and positively correlated with non-HDL-C, HOMA-IR and serotonin/plt (P<0.05). Moreover, serotonin/plt inversely correlated with PAT ratio (P<0.05). Smokers who completely attained smoking cessation were improved PAT ratio (P<0.05) and increased plasma miR-126 (P<0.05), however serotonin and serotonin/plt were not significantly changed.
Conclusions: Increased plasma serotonin levels are associated with vascular damage in smokers. Endothelial function was improved with increased plasma miR-126 after 8 weeks smoking cessation although plasma levels of serotonin and serotonin/plt were persistently elevated. These results suggest that caution should be taken during plasma serotonin levels are not decreased even after improvement of endothelial function.
- © 2013 by American Heart Association, Inc.