The Effects of Acute Passive Smoke Exposure on Endothelium-Dependent Brachial Artery Dilation in Healthy Individuals

Influence of environmental tobacco smoke on morphology and functions of cardiovascular system assessed using diagnostic imaging

Exposure to tobacco smoke is a significant problem of environmental medicine. Tobacco smoke contains over one thousand identified chemicals including numerous toxicants. Cardiovascular system diseases are the major cause of general mortality. The recent development of diagnostic imaging provided methods which enable faster and more precise diagnosis of numerous diseases, also those of cardiovascular system. This paper reviews the most significant scientific research concerning relationship between environmental exposure to tobacco smoke and the morphology and function of cardiovascular system carried out using diagnostic imaging methods, i.e. ultrasonography, angiography, computed tomography and magnetic resonance imaging. In the forthcoming future, the studies using current diagnostic imaging methods should contribute to the reliable documentation, followed by the wide-spreading knowledge of the harmful impact of the environmental tobacco smoke exposure on the cardiovascular system.

Tobacco Use is a Modifiable Risk Factor for Post-Transplant Biliary Complications

PURPOSE

Biliary complications following liver transplantation are a significant source of morbidity, potentially leading to graft failure necessitating retransplantation. We sought to evaluate smoking as an independent risk factor for post-transplant biliary complications.

METHODS

The clinical course of all adult primary deceased donor liver transplants at our center from 1992 to 2012 was reviewed. Eligible patients were assigned to cohorts based on their lifetime tobacco exposure: never smokers indicating 0 pack-year exposure and all others were ever smokers. Biliary complications were defined as strictures, leaks, or bilomas requiring intervention. Complication rates were analyzed using univariate regression models correlated with donor and recipient characteristics. Associations found during univariate analysis were included in the final multivariate Cox model.

RESULTS

Eight hundred sixty-five subjects were followed for a median of 65 months; 482 (55.7%) of patients had a positive smoking history at the time of transplant. In univariate analysis, positive tobacco smoking history (HR = 1.36; p = 0.037) and increased time from quit date to transplantation (HR = 0.998; p = 0.011) were positive and negative predictors of biliary complication, respectively. Lifetime tobacco exposure remained a significant predictor of biliary complication on multivariate analysis (HR = 1.408; p = 0.023).

CONCLUSIONS

Smoking status is an independent predictor of post-transplant biliary complications, and the data presented reinforces the importance of early smoking cessation in the pre-transplantation period.

Immediate effect of passive smoking on microcirculatory flow

OBJECTIVE

Exposure to SHS, as by passive smoking, seems to increase the incidence of cardiovascular events. It has been shown that active smoking of a single cigarette causes an immediate and significant decrease in microcirculatory blood flow velocity, whereas the acute effects of exposure to SHS on microcirculatory flow have as yet not been demonstrated.

METHODS

Healthy nonsmoking volunteers of both genders were studied during acute exposure to SHS of two cigarettes burning up to 10 minutes. Microvessels were examined by in vivo vital capillaroscopy (Capiflow(®)), allowing continuous assessment of CBV.

RESULTS

CBV decreased from 514 mm/sec (CI 383-646) at baseline to 306 mm/sec (CI 191-420) at end of SHS exposure with a further decrease to a nadir of 240 mm/sec (CI 155-325) four minutes after the end of this exposure (p < 0.0001; ANOVA).

CONCLUSIONS

The result of this study shows that passive inhalation of secondhand cigarette smoke induces an immediate and prolonged marked reduction in CBV in nonsmoking healthy volunteers.

Environmental tobacco smoke exposure and diabetes in adult never-smokers

BACKGROUND

Active smoking has been linked to type 2 diabetes mellitus (T2DM) but only few recent studies have shown environmental tobacco smoke (ETS) to be associated with DM in never-smokers. We assessed the association between long term ETS exposure and DM, and explored effect modifications of this association in our sample.

METHODS

We analysed 6392 participants of the Swiss study on air pollution and lung and heart diseases in adults (SAPALDIA). We used mixed logistic regression models to assess the cross-sectional association between ETS and DM. Selected variables were tested for effect modification and several sensitivity analyses were performed, mostly treating participants' study area as a random effect.

RESULTS

The prevalence of DM and ETS in the sample was 5.5% and 47% respectively. There were 2779 never-smokers with 4% diabetes prevalence. Exposure to ETS increased risk of DM in never-smokers by 50% [95% confidence interval (CI): 1.00, 2.26], and we observed a positive dose-response relationship between ETS exposure level and DM in never-smokers. Associations were strengthened (more than three-folds) by older age and chronic obstructive pulmonary disease, and were stronger in post-menopausal, obese, hypertriglyceridaemic and physically inactive participants. Estimates of association were robust across all sensitivity analyses (including inverse probability weighting for participation bias and fixed-effect analysis for study area). ETS had no substantial associations in current and ex-smokers in our study.

CONCLUSIONS

We found a positive association between ETS exposure and DM in never smokers. Additional longitudinal studies involving biomarkers are needed to further explore underlying mechanisms and susceptibilities.

Brief exposure to secondhand smoke reversibly impairs endothelial vasodilatory function

INTRODUCTION

We sought to determine the effects of brief exposures to low concentrations of tobacco secondhand smoke (SHS) on arterial flow-mediated dilation (FMD, a nitric oxide-dependent measure of vascular endothelial function), in a controlled animal model never before exposed to smoke. In humans, SHS exposure for 30 min impairs FMD. It is important to gain a better understanding of the acute effects of exposure to SHS at low concentrations and for brief periods of time.

METHODS

We measured changes in FMD in rats exposed to a range of real-world levels of SHS for durations of 30 min, 10 min, 1 min, and 4 breaths (roughly 15 s).

RESULTS

We observed a dose-response relationship between SHS particle concentration over 30 min and post-exposure impairment of FMD, which was linear through the range typically encountered in smoky restaurants and then saturated at higher concentrations. One min of exposure to SHS at moderate concentrations was sufficient to impair FMD.

CONCLUSIONS

Brief SHS exposure at real-world levels reversibly impairs FMD. Even 1 min of SHS exposure can cause reduction of endothelial function.

Fish oil blunted nicotine-induced vascular endothelial abnormalities possibly via activation of PPARγ-eNOS-NO signals

Nicotine exposure is associated with an induction of vascular endothelial dysfunction (VED), a hallmark of various cardiovascular disorders. The present study investigated the effect of fish oil in nicotine-induced experimental VED. VED was assessed by employing isolated aortic ring preparation, estimating aortic and serum nitrite/nitrate, aortic superoxide anion generation, and serum TBARS, and carrying out electron microscopic and histological studies of thoracic aorta. Nicotine (2 mg/kg/day, i.p., 4 weeks) administration produced VED in rats by attenuating acetylcholine-induced endothelium-dependent relaxation in the isolated aortic ring preparation, decreasing aortic and serum nitrite/nitrate concentration, impairing endothelial integrity, and inducing vascular oxidative stress. Treatment with fish oil (2 mL/kg/day p.o., 4 weeks) markedly prevented nicotine-induced endothelial functional and structural abnormalities and oxidative stress. However, administration of GW9662, a selective inhibitor of PPARγ, to a significant degree attenuated fish oil-associated anti-oxidant action and vascular endothelial functional and structural improvements. Intriguingly, in vitro incubation of L-NAME (100 μM), an inhibitor of nitric oxide synthase (NOS), markedly attenuated fish oil-induced improvement in endothelium-dependent relaxation in the aorta of nicotine-administered rats. Nicotine administration altered the lipid profile by increasing serum total cholesterol, which was significantly prevented by fish oil treatment. The vascular protective potential of fish oil in preventing nicotine-induced VED may pertain to its additional properties (besides its lipid-lowering effect) such as activation of PPARγ and subsequent possible activation of endothelial NOS and generation of nitric oxide, and consequent reduction in oxidative stress.

Acute effects of second-hand smoke on complete blood count

We assessed the acute effects of a 1-h exposure to second-hand smoke (SHS) on complete blood count (CBC) markers in a controlled simulated bar/restaurant environment. Nineteen adult never-smokers completed a 1-h .exposure to SHS at bar/restaurant levels, and a 1-h exposure to normal room air. Blood samples were collected at the baseline at 30 min during each exposure, and at 0, 0.5, 1, 2, 3, and 4 h after each exposure. The values of white blood cells (WBC) at 1 h (p = 0.010), 3 h (p = 0.040), and 4 h (p = 0.008) following SHS were significantly increased compared with the baseline values. Also, there was a positive association between the WBC and cotinine levels (r = 0.28, p = 0.007). A 1-h exposure to SHS at bar/restaurant levels significantly increased the WBC for at least 4 h following the exposure time. This effect of SHS on WBC has dose-response characteristics and should be considered to prescribing CBC.

Second-hand tobacco smoke and cardiovascular disease risk: an epidemiological review

In this review, we have sought to examine the epidemiological, basic science, and public health data regarding the association between second-hand smoke (SHS) exposure and the development of coronary heart disease (CHD). SHS increases the risk of CHD by 25-30% according to multiple cohort, case-control, and meta-analytical studies. Physiologic and basic science research suggest that the mechanisms by which SHS affects the cardiovascular system are multiple and include increased thrombogenesis and low-density lipoprotein oxidation, decreased exercise tolerance, dysfunctional flow-mediated vasodilatation, and activation of inflammatory pathways with concomitant oxidative damage and impaired vascular repair. As a result, chronic exposure promotes atherogenesis and the development of cardiovascular disease, increasing the risk of having an acute coronary syndrome (ACS). With the implementation of statewide and nationwide public smoke-free legislation across the United States and Europe, respectively, over the last 10-15 years, there has been a significant and reciprocal decline in the incidence of emergency admissions for ACS by an average 17% despite persistent attempts on the part of the tobacco industry to diminish the correlation between SHS exposure and CHD. These findings underscore the importance of the effects of smoking legislation on community health.

Secondhand smoke exposure levels in outdoor hospitality venues: a qualitative and quantitative review of the research literature

OBJECTIVE

This paper considers the evidence on whether outdoor secondhand smoke (SHS) is present in hospitality venues at high levels enough to potentially pose health risks, particularly among employees.

DATA SOURCES

Searches in PubMed and Web of Science included combinations of environmental tobacco smoke, secondhand smoke, or passive smoke AND outdoor, yielding 217 and 5,199 results, respectively through June, 2012.

STUDY SELECTION

Sixteen studies were selected that reported measuring any outdoor SHS exposures (particulate matter (PM) or other SHS indicators).

DATA EXTRACTION

The SHS measurement methods were assessed for inclusion of extraneous variables that may affect levels or the corroboration of measurements with known standards.

DATA SYNTHESIS

The magnitude of SHS exposure (PM2.5) depends on the number of smokers present, measurement proximity, outdoor enclosures, and wind. Annual excess PM2.5 exposure of full-time waitstaff at outdoor smoking environments could average 4.0 to 12.2 μg/m3 under variable smoking conditions.

CONCLUSIONS

Although highly transitory, outdoor SHS exposures could occasionally exceed annual ambient air quality exposure guidelines. Personal monitoring studies of waitstaff are warranted to corroborate these modeled estimates.

Acute effects of electronic and tobacco cigarette smoking on complete blood count

The World Health Organisation called for research assessing the safety of electronic cigarette (e-cigarette). We evaluated the acute effect of active and passive e-cigarette and tobacco cigarette smoking on complete blood count (CBC) markers in 15 smokers and 15 never-smokers, respectively. Smokers underwent a control session, an active tobacco cigarette smoking session, and an active e-cigarette smoking session. Never-smokers underwent a control session, a passive tobacco cigarette smoking session, and a passive e-cigarette smoking session. The results demonstrated that CBC indices remained unchanged during the control session and the active and passive e-cigarette smoking sessions (P>0.05). Active and passive tobacco cigarette smoking increased white blood cell, lymphocyte, and granulocyte counts for at least one hour in smokers and never smokers (P<0.05). It is concluded that acute active and passive smoking using the e-cigarettes tested in the current study does not influence CBC indices in smokers and never smokers, respectively. In contrast, acute active and passive tobacco cigarette smoking increase the secondary proteins of acute inflammatory load for at least one hour. More research is needed to evaluate chemical safety issues and other areas of consumer product safety of e-cigarettes, because the nicotine content in the liquids used may vary considerably.

Comparison of coronary microcirculation in female nurses after day-time versus night-time shifts

Nightshift work, which is known to cause mental stress and disrupt normal biological diurnal rhythms, leads to endothelial dysfunction resulting in increased risk for cardiovascular disease. This study aimed to investigate the acute effect of night-shift work on coronary microcirculation through assessment of coronary flow reserve (CFR) by transthoracic Doppler echocardiography. This study consisted of 36 women nurses who underwent transthoracic Doppler echocardiographic examinations after working a nightshift and on a regular day without previous nightshift work. Flow velocity in the distal portion of the left anterior descending coronary artery was measured at baseline and during adenosine infusion. CFR was calculated as the ratio of hyperemic to basal mean diastolic flow velocity. CFR after night work was lower than that on a regular workday (3.8 ± 0.6 vs 4.1 ± 0.6, p <0.001). Degree of decreases in CFR after night work was correlated to Framingham risk score (r = 0.35, p = 0.036). In conclusion, this study demonstrated that coronary microcirculation was impaired after nightshift work in women nurses.

Is acute high-dose secondhand smoke exposure always harmful to microvascular function in healthy adults?

Prev Cardiol. Long-term exposure to secondhand smoke (SHS) is associated with impaired vascular function. The authors investigated the vascular and blood pressure (BP) reactions to acute SHS exposure. Twenty-five healthy nonsmoking adults underwent a 1-hour exposure to SHS (mean fine particulate matter < 2.5 μm level = 315 ± 116 μg/m(3) ). Microvascular endothelial-dependent vasodilatation (EDV) (EndoPAT, Itamar Medical, Caesarea, Israel) and aortic hemodynamics/compliance (SphygmoCor, AtCor Medical, West Ryde, Australia) were measured before and after the SHS exposure with BP measured every 15 minutes during and for a 24-hour period before and after the exposure. SHS exposure did not change EDV, aortic hemodynamics, arterial compliance, or 24-hour BP. However, diastolic BP significantly increased during the SHS exposure period by 3.4 ± 5.6 mm Hg. Our brief SHS exposure did not impair microvascular endothelial function or arterial compliance in healthy nonsmoking adults, but brachial diastolic BP increased.

Effects of environmental tobacco smoke on the pulmonary circulation in the ovine fetus

OBJECTIVE

Epidemiologic studies have highlighted an association between maternal smoking and persistent pulmonary hypertension of the newborn infant. However, the impact of exposure to tobacco smoke on the perinatal pulmonary circulation is currently unknown. The purpose of this study was to assess the pulmonary vascular effects of environmental tobacco smoke in the fetus.

STUDY DESIGN

We performed surgery on 16 fetal lambs and placed catheters in the main pulmonary artery, aorta, and left atrium to measure pressures. An ultrasonic blood flow transducer was placed around the left pulmonary artery to measure blood flow. The ewes were exposed to tobacco smoke for 2 hours. In another set of experiments, the pulmonary vascular response to increased fetal O(2) tension has been assessed after 2 hours of tobacco smoke inhalation or not (control group).

RESULTS

Exposure to tobacco smoke decreased pulmonary blood flow by 30% and elevated pulmonary vascular resistance by 40%. The vasodilator response to increased O(2) tension was blunted after smoke inhalation compared with control animals. Smoke inhalation was associated with a decrease in fetal PaO(2) and SaO(2).

CONCLUSION

Exposure to environmental tobacco smoke in pregnant ewes impairs both basal tone and vascular reactivity of the fetal lung.

Effect of brief secondhand smoke exposure on endothelial function and circulating markers of inflammation

OBJECTIVE

In contrast to the well defined detrimental consequences of long-term secondhand smoke (SHS) exposure, little is known about the acute effects of passive smoking on endothelial function and inflammation. The aim of the present study was to assess the acute effects of short-term SHS exposure on endothelial function and circulating markers of inflammation.

METHODS

Peripheral microvascular endothelial function assessed by reactive hyperemia peripheral arterial tonometry (RH-PAT) index, circulating markers of endothelial function (von Willebrand factor antigen, Thrombomodulin, E-selectin) and circulating inflammatory markers (high sensitivity C-reactive protein (hsCRP), Interleukin-6 (IL-6)) were measured in eighteen male, non-smoking volunteers before and 12h after a 1-h SHS exposure.

RESULTS

Twelve hours after passive smoking, average RH-PAT index was significantly lower than before SHS exposure (1.54±0.49 vs 2.01±0.55 (mean±SD), p=0.01) indicating deterioration of peripheral microvascular endothelial function. von Willebrand factor antigen as a marker of endothelial activation was significantly increased after SHS exposure (93.0±25.5% vs 78.4±17.9%, p=0.03). Levels of Thrombomodulin, E-selectin, hsCRP, and IL-6 were unaffected by SHS exposure.

CONCLUSION

Short-term SHS exposure leads to a measurable disturbance of endothelial function. However, 1h of passive smoking appears to be too short to elicit a significant inflammatory response.

Aromatherapy alleviates endothelial dysfunction of medical staff after night-shift work: preliminary observations

Night-shift work causes mental stress and lifestyle changes, and is recognized as a risk of cardiovascular diseases associated with impaired endothelial function. Aromatherapy is becoming popular as a complementary therapy that is beneficial for mental relaxation. The purpose of this study was to investigate the effect of aromatherapy on the endothelial function of medical staff after night-shift work. This study consisted of 19 healthy medical personnel (19 men, mean age 32 ± 7 years), including 11 physicians and 8 technicians. Aromatherapy was performed for 30 min by inhalation of the essential oil of lavender. Flow-mediated dilation (FMD) of the brachial artery was measured three times in each subject: on a regular workday, and after night-shift work before and immediately after aromatherapy. A control study was performed to assess the effect of a 30-min rest without aromatherapy. The mean value of sleep time during night-shift work was 3.3 ± 1.3 h. FMD after night-shift work was lower than on a regular workday (10.4 ± 1.8 vs. 12.5 ± 1.7%, P<0.001), which improved after aromatherapy (11.8 ± 2.5%, P=0.02 vs. before aromatherapy). FMD was stable in the control study (10.1 ± 1.9 vs. 10.1 ± 2.2%, P=0.9). This study demonstrated that night-shift work impaired endothelial function in medical staff, an effect that was alleviated by short-term aromatherapy.

Acute effects of passive smoking on endothelial function

Impairment of endothelial functions has been shown to occur after acute and chronic exposure to passive smoking (PS), as assessed by flow-mediated dilatation (FMD) of the brachial artery. A total of 61 participants, 30 male and 31 female, mean ages 26 (18-36) were enrolled in the study. All were clinically well and nonsmokers. All participants stayed for 30 minutes in the smoking room. Carbon monoxide (CO) level was 7.42 ± 0.98 ppm (4.71-10.50). Mean carboxyhemoglobin (COHb) levels of participants were significantly elevated after PS. Mean FMD was 18.6% ± 9% and decreased to 12.4% ± 7% after PS (P < .001). In the current study, with more number of participants at lower CO concentrations (7.42 ppm) and with smaller increase in COHb (51%) significant reduction (33%, P < .001) in FMD was observed.

Exhaled carbon monoxide screening for environmental tobacco smoke exposure in preanesthetic children

OBJECTIVE

Exposure to environmental tobacco smoke (ETS) is associated with an increased risk of perioperative adverse events in children. The purpose of this study was to evaluate exhaled carbon monoxide (CO) as a preoperative ETS screening tool in children.

METHODS

Five hundred and one children aged 6-15 years were enrolled. The child's guardian completed a questionnaire that surveyed environmental exposures to CO and ETS. A preoperative urine sample was obtained from children who assented and were able to void, and urine cotinine values were measured. Exhaled CO was measured using the EC50-Micro Smokerlyzer (Bedfont Scientific Ltd, UK).

RESULTS

Four hundred and fifty-one subjects completed the study, and urine samples were obtained from 83. 25% of subjects were classified as exposed to ETS based on questionnaire results. Exhaled CO values did not correlate with either the qualitative (questionnaire) or quantitative (urine cotinine) measurements of ETS exposure. Exhaled CO predicted a urine cotinine/creatinine ratio >10 with a sensitivity of 10% and a specificity of 85%.

CONCLUSION

Exhaled CO measured by this device is not a useful preoperative screening tool for ETS exposure in children. Because exhaled CO has been used successfully to monitor ETS exposure in adolescents, we believe that its failure in our population is as a result of the limited ability of small children to perform vital capacity maneuvers in order to provide an adequate endtidal sample.

Association between abnormal uterine artery Doppler flow velocimetry, risk of preeclampsia, and indices of arterial structure and function: a pilot study

Preeclampsia increases the risk of future cardiovascular disease. The association between abnormal uterine artery Doppler flow velocimetry, risk of preeclampsia, and indices of arterial structure and function is investigated in this study. The carotid intima-media thickness of 34 pregnant women with normal uteroplacental flow was compared with 30 women with abnormal uterine artery Doppler analysis during the transvaginal assessment of the uterine arteries at the routine anomaly scan (20-23 weeks of gestation). Women with abnormal uterine artery Doppler results had a greater mean internal (but not common) carotid intima-media thickness (0.58 +/- 0.06 vs 0.53 +/- 0.08, respectively, P = .005) and risk of developing preeclampsia (6 of 30 vs 0 of 34 or 20% vs 0%, respectively, P = .0079) compared with those with normal uteroplacental flow. Women with abnormal uterine artery Doppler results may be at increased risk not only for developing subsequent preeclampsia but also for future cardiovascular disease.

Do Different Vascular Risk Factors Affect All Arteries Equally?

Established vascular risk factors (ie, smoking, hypertension, diabetes mellitus, and dyslipidemia) play an important role in the development of vascular disease. Emerging evidence suggests that some of these risk factors may have a more intense effect on specific arterial beds, a finding that holds implications for a prognostic role for certain types of vascular disease.