Effect of cigarette smoke extract on arteriolar dilatation in vivo

Diabetes- versus smoking-related thrombo-inflammation in peripheral artery disease

Peripheral artery disease (PAD) is a major health problem with increased cardiovascular mortality, morbidity and disabling critical limb threatening ischemia (CLTI) and amputation. Diabetes mellitus (DM) and cigarette smoke are the main risk factors for the development of PAD. Although diabetes related PAD shows an accelerated course with worse outcome regarding complications, mortality and amputations compared with non-diabetic patients, current medical treatment does not make this distinction and includes standard antiplatelet and lipid lowering drugs for all patients with PAD. In this review we discuss the pathophysiologic mechanisms of PAD, with focus on differences in thrombo-inflammatory processes between diabetes-related and smoking-related PAD, and hypothesize on possible mechanisms for the progressive course of PAD in DM. Furthermore, we comment on current medical treatment and speculate on alternative medical drug options for patients with PAD and DM.

Risk Factors and Immunoinflammatory Mechanisms Leading to Atherosclerosis: Focus on the Role of Oral Microbiota Dysbiosis

Cardiovascular diseases (CVD), including myocardial infarction and stroke, are currently the leading cause of morbidity, disability and mortality worldwide. Recently, researchers have focused their attention on the alterations of the gut and oral microbiota, investigating the possible role of their dysbiosis in the pathogenesis and/or progression of CVD. In this regard, it has been shown that endothelial dysfunction, a major feature of CVD, can also be induced by chronic periodontal infection, due to a systemic pro-inflammatory condition, as suggested by increased plasma levels of acute phase proteins, IL-6 and fibrinogen. Moreover, proatherogenic dysfunctions can also be promoted by direct bacterial invasion of the endothelium. This review reports the current evidence about the possible role of oral microbiota dysbiosis and the related immunoinflammatory components in the pathophysiology of atherosclerosis and associated CVD. It is concluded that integration of oral microbiota sampling into clinical practice may result in a more accurate assessment of CV risk in patients and even modify their prognosis.

Systemic and Coronary Hemodynamic Effects of Tobacco Products on the Cardiovascular System and Potential Pathophysiologic Mechanisms

Tobacco product usage is the single most preventable cause of death in the United States. Smoking promotes atherosclerosis, producing disease in the coronary arteries, the aorta, the carotid and cerebral arteries and the large arteries in the peripheral circulation. The cardiovascular consequences of tobacco products have been the subject of intensive study for several decades. Despite the overwhelming epidemiologic association between smoking and vascular disease, the pathophysiologic mechanisms by which smoking exerts its deleterious effects remain incompletely understood. This review addresses the acute and long-term systemic and coronary hemodynamic effects of tobacco, with an emphasis of the impact on coronary blood flow and pathophysiologic mechanisms.

Post-Stroke Outcomes of Patients with Chronic Obstructive Pulmonary Disease

Introduction: Research has shown that patients with ischemic stroke and coexisting obstructive respiratory disorders have worse clinical status on admission and increased long-term mortality. Patients with chronic obstructive pulmonary disease (COPD) are at increased risk of stroke, and the risk is even greater after exacerbation of COPD. Moreover, COPD and stroke share major risk factors, which are advancing age and smoking. The aim of this study was to analyze the incidence of complications and mortality in acute ischemic stroke (AIS) patients with and without COPD. Material and methods: We analyzed prospectively collected data of 1022 patients with acute is-chemic stroke hospitalized in a district general hospital. The patients were divided into two groups—with coexisting COPD and without COPD. Results: Logistic regression analysis, which allowed for potential confounders, showed an association between coexisting COPD and the fol-lowing complications in acute ischemic stroke patients: heart failure (OR = 1.879, p = 0.048), atrial fibrillation (OR = 4.746, p = 0.012), delirium (OR = 2.803, p < 0.001), pneumonia (OR = 2.424, p = 0.005), bronchospasm (OR = 3.400, p = 0.023), and out-hospital mortality (OR = 2.656, p = 0.001). Conclusion: Patients presenting with acute ischemic stroke and coexisting COPD significantly more often had cardiac and pulmonary complications, as well as delirium following stroke. In a long-term follow-up, the probability of one-year survival was significantly lower in AIS patients with co-existing COPD.

p19Arf Exacerbates Cigarette Smoke-Induced Pulmonary Dysfunction

Senescent cells accumulate in tissues during aging or pathological settings. The semi-genetic or pharmacological targeting of senescent cells revealed that cellular senescence underlies many aspects of the aging-associated phenotype and diseases. We previously reported that cellular senescence contributes to aging- and disease-associated pulmonary dysfunction. We herein report that the elimination of Arf-expressing cells ameliorates cigarette smoke-induced lung pathologies in mice. Cigarette smoke induced the expression of Ink4a and Arf in lung tissue with concomitant increases in lung tissue compliance and alveolar airspace. The elimination of Arf-expressing cells prior to cigarette smoke exposure protected against these changes. Furthermore, the administration of cigarette smoke extract lead to pulmonary dysfunction, which was ameliorated by subsequent senescent cell elimination. Collectively, these results suggest that senescent cells are a potential therapeutic target for cigarette smoking-associated lung disease.

Association of smoking cessation after atrial fibrillation diagnosis on the risk of cardiovascular disease: a cohort study of South Korean men

BACKGROUND

While smoking elevates the risk for cardiovascular disease (CVD) among atrial fibrillation (AF) patients, whether smoking cessation after AF diagnosis actually leads to reduced CVD risk is unclear. We aimed to determine the association of smoking cessation after AF diagnosis with subsequent CVD Risk among South Korean men.

METHODS

This retrospective cohort study included 2372 newly diagnosed AF male patients during 2003-2012 from the Korean National Health Insurance Service database. Self-reported smoking status within 2 years before and after diagnosis date were determined, after which the participants were divided into continual smokers, quitters (smokers who quit after AF diagnosis), sustained-ex smokers (those who quit prior to AF diagnosis), and never smokers. Participants were followed up from 2 years after AF diagnosis until 31 December 2015 for CVD. Cox proportional hazards regression was used to determine the adjusted hazard ratios (aHRs) and 95% confidence interval (CIs) for CVD according to the change in smoking habits before and after AF diagnosis.

RESULTS

The mean (standard deviation, minimum-maximum) age of the study subjects was 62.5 (8.6, 41-89) years. Among AF patients, quitters had 35% reduced risk (aHR 0.65, 95% CI 0.44-0.97) and never smokers had 32% reduced risk (aHR 0.68, 95% CI 0.52-0.90) for CVD compared to continual smokers (p for trend 0.020). Similarly, compared to continual smokers, quitters had 41% risk-reduction (aHR 0.59, 95% CI 0.35-0.99) and never smokers 34% risk-reduction (aHR 0.66, 95% CI 0.46-0.93) for total stroke (p for trend 0.047). Quitters had 50% reduction (aHR 0.50, 95% CI 0.27-0.94), sustained ex-smokers had 36% reduction (aHR 0.64, 95% CI 0.42-0.99), and never smokers had 39% reduction (aHR 0.61, 95% CI 0.41-0.91) in ischemic stroke risk (p for trend 0.047). The risk-reducing effect of quitting on CVD risk tended to be preserved regardless of aspirin or warfarin use.

CONCLUSIONS

Smoking cessation after AF diagnosis was associated with reduced CVD, total stroke, and ischemic stroke risk.

Passive smoking and cardiometabolic risk factors in Iranian children and adolescents: CASPIAN-V study

Background

Smoking behavior as a harmful trend among adolescents and young adults has increased over last two decades. Many children and adolescents are at the risk of "second-hand" smoking at home due to their exposure to parents' or siblings' smoking. These second hand smokers are called "passive smokers" and are at risk of several health complications like cardiometabolic risk factors.

Objectives

The present study aims to evaluate the association between passive smoking and increase of cardiometabolic risk factors in a sample of Iranian's children and adolescents, aged 7-18 years.

Methods

This multicenter cross-sectional study was carried out over 14,400 students (aged 7-18 years). Blood sampling were randomly collected from a sub-sample of 4200 selected pupils. According to their degree of exposure to smoke for both cigarette and hookah, water pipes that are used to smoke specially made tobacco that comes in different flavors, all participants were divided to the two separate groups of positive and negative exposure. Metabolic syndrome (MetS) is defined as a constellation of at least three out of five cardiometabolic risk factors, including abdominal obesity, elevated blood pressure, elevated fasting plasma glucose concentration, high serum levels of triglycerides (TG), and depressed high-density cholesterol (HDL-C) levels.

Results

The mean and standard deviation (SD) age of participants was 12.3 ± 2.24 years. 49.4% were girls and 71.4% of them were urban residents. The mean SD for BMI of participants was 18.5 (4.7) Kg/m2. The mean TG levels were considerably higher among passive smoker children and adolescents. MetS and being overweight were found to have a major association with passive smoking (OR 1.63 CI 95% 1.17-2.29 P Value 0.004 and OR 1.21 95% CI 1.06-1.37 P Value 0.004, respectively).

Conclusion

This study confirms that passive smoking or second-hand smoking is linked with the increased prevalence of cardiometabolic risk factors and places children and adolescents at a higher risk of being overweight. Preventive strategies could be incorporated against passive smoking to recognize it as a health priority among children and adolescents.

Functional, Cellular, and Molecular Remodeling of the Heart under Influence of Oxidative Cigarette Tobacco Smoke

Passive and active chronic cigarette smoking (CS) remains an international epidemic and a key risk factor for cardiovascular disease (CVD) development. CS-induced cardiac damage is divided into two major and interchangeable mechanisms: (1) direct adverse effects on the myocardium causing smoking cardiomyopathy and (2) indirect effects on the myocardium by fueling comorbidities such as atherosclerotic syndromes and hypertension that eventually damage and remodel the heart. To date, our understanding of cardiac remodeling following acute and chronic smoking exposure is not well elucidated. This manuscript presents for the first time the RIMD (oxidative stress (R), inflammation (I), metabolic impairment (M), and cell death (D)) detrimental cycle concept as a major player in CS-induced CVD risks and direct cardiac injury. Breakthroughs and latest findings in the field with respect to structural, functional, cellular, and molecular cardiac remodeling following chronic smoking exposure are summarized. This review also touches the genetics/epigenetics of smoking as well as the smoker's paradox and highlights the most currently prominent pharmacological venues to mitigate CS-induced adverse cardiac remodeling.

COPD and stroke: are systemic inflammation and oxidative stress the missing links?

Chronic obstructive pulmonary disease (COPD) is characterized by progressive airflow limitation and loss of lung function, and is currently the third largest cause of death in the world. It is now well established that cardiovascular-related comorbidities such as stroke contribute to morbidity and mortality in COPD. The mechanisms linking COPD and stroke remain to be fully defined but are likely to be interconnected. The association between COPD and stroke may be largely dependent on shared risk factors such as aging and smoking, or the association of COPD with traditional stroke risk factors. In addition, we propose that COPD-related systemic inflammation and oxidative stress may play important roles by promoting cerebral vascular dysfunction and platelet hyperactivity. In this review, we briefly discuss the pathogenesis of COPD, acute exacerbations of COPD (AECOPD) and cardiovascular comorbidities associated with COPD, in particular stroke. We also highlight and discuss the potential mechanisms underpinning the link between COPD and stroke, with a particular focus on the roles of systemic inflammation and oxidative stress.

Circulating level of microRNA-126 may be a potential biomarker for recovery from smoking-related vascular damage in middle-aged habitual smokers

BACKGROUND

Cigarette smoking promotes vascular endothelial damage and accelerates progression of atherosclerosis. The purpose of this study was to examine whether the circulating level of vascular endothelium-enriched microRNA-126 (miR-126), which is highlighted as a regulator of gene expression, would serve as a novel biomarker for recovery from smoking-related vascular damage.

METHODS

Middle-aged male smokers (n = 30) were enrolled and instructed to stop smoking. Their clinical profiles and laboratory findings including expression of miR-126 were investigated before and after 8 weeks of smoking cessation. Serum levels of cotinine, metabolites of nicotine, were measured to confirm smoking cessation. Endothelial function for peripheral small vessels was assessed and expressed as reactive hyperemia peripheral arterial tonometry (RH-PAT) index. The expression of miR-126 in plasma was analyzed by quantitative real-time PCR.

RESULTS

At baseline, serum cotinine levels were inversely correlated with RH-PAT index (r = - 0.48, P < 0.01) and positively correlated with levels of metabolic parameters such as non-HDL cholesterol (r = 0.53, P < 0.01) and HOMA-IR (r = 0.52, P < 0.01). The RH-PAT index was not significantly changed after 8 weeks in all subjects, because only 13 subjects could attain smoking cessation. However, changes in the RH-PAT index showed a significant correlation with those in systolic blood pressure (r = - 0.54, P < 0.01). In smokers who completely attained smoking cessation (n = 13), RH-PAT index and plasma levels of miR-126 were significantly increased (P < 0.05, respectively).

CONCLUSIONS

Endothelial damage was improved and plasma levels of circulating miR-126 were increased after 8 weeks of smoking cessation. These findings suggested a potential use of miR-126 as a biomarker for recovery from smoking-induced vascular damage.

Haemodynamic responses to tobacco smoke inhalation in male adolescents in Lusaka, Zambia

Background

Tobacco smoke causes changes in the levels of catecholamines in the blood. This leads to an increase in blood pressure and heart rate. This is due to nicotine which has also been noted to cause a decrease in vasodilatory activities leading to an increase in both the blood pressure and heart rate.

Aim

To determine the acute effects of tobacco smoke on haemodynamics in black male adolescents in Lusaka, Zambia.

Study design

This was an observational study done at the University of Zambia School of Medicine Cardiovascular Research Laboratory in the month of December, 2014.

Methodology

Twenty-two (22) black, male-adolescent (age range 19-25 years), active-smokers, consented to participate in the study. The Diasys Ambulatory Blood Pressure Monitoring system (Novacor, France) was used to obtain the Systolic and Diastolic blood pressures (SBP and DBP) and the heart rate. These were obtained 15 minutes before smoking at 5 minute intervals and averaged to obtain the baseline, during the 15 minutes of smoking and on immediate cessation of smoking and thereafter every 15 minutes up to an hour after smoking.

Results

There was a significant rise in SBP (mmHg) during smoking (127.9 ± 13.80 mmHg) from baseline values (113.5 ± 13.15 mmHg) (P = .00). It took 30 minutes for the SBP to return to baseline after cessation of smoking. DBP (mmHg) also increased from baseline (79.5 ± 8.79 mmHg) to 85.6 ± 10.92 mmHg during smoking (P = .01). It returned to baseline values immediately after cessation of smoking. The heart rate (bpm) was also noted to significantly increase during smoking (95.2 ± 16.72 bpm) from the values noted before smoking (74.3 ± 13.75 bpm) (P = .05). The mean value for heart rate returned to baseline value by the 15^th minute of recovery.

Conclusion

The present study demonstrates that smoking may be the cause for the acute increases in SBP, DBP and heart rate in smokers. The smoking caused significant increases in all the haemodynamic indices considered in this study within 15 minutes. Both SBP and DBP increase are indices for stroke and coronary heart disease respectively. The effect of increased SBP was noted to last for 30 minutes while DBP returned to baseline immediately after smoking. A significant increase in heart rate was also noted in the study.

What can in vitro models of COPD tell us?

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterised by chronic bronchitis, largely irreversible remodelling of the small airways, and emphysematous destruction of the alveoli. COPD is projected to be the third leading cause of death worldwide by 2020. COPD often results from prolonged exposure to irritants such as cigarette smoke or inhaled particulates. Current pharmacotherapies for COPD are unable to reverse the pathological changes of this disease, and this is partially due to a limited understanding of the intricate mechanisms by which chronic exposure lead to the different pathological components of COPD. This review examines how the mechanisms that underlie various components of COPD can be modelled in vitro, specifically using cigarette smoke extract with cells cultured from primary human lung tissue, and how the effectiveness of current and novel pharmacotherapies on successfully attenuating these pathological changes can also be examined in vitro.

Smoking decreases the level of circulating CD34+ progenitor cells in young healthy women--a pilot study

BACKGROUND

Decreased levels of circulating bone marrow-derived progenitor cells have been associated with risk factors and cardiovascular diseases. Smoking is the most important modifiable risk factor for atherosclerosis in young women. The aim of this pilot study was to assess in healthy premenopausal women without other risk factors for cardiovascular disease the influence of nicotine abuse on the number of circulating progenitor cells in relation to endothelial function.

METHODS

The number of endothelial progenitor cells, measured as colony-forming units in a cell-culture assay (EPC-CFU) and the number of circulating CD34 + and CD34 + /CD133 + cells, measured by flow cytometry, was estimated in 32 women at the menstrual phase of the menstrual cycle. In addition, flow-mediated dilation (FMD) was assessed as a marker for vascular function. In a subgroup of these women (n = 20), progenitor cells were also investigated at the mid-follicular and luteal phases of the menstrual cycle.

RESULTS

Compared to non-smokers, the abundance of circulating CD34 + cells was significantly lower in smoking women in the menstrual, mid-luteal, and mid-follicular phases of the menstrual cycle. The number of CD34 + progenitor cells was revealed to have significant positive correlation with FMD in young healthy women, whereas CD34 + /CD133 + progenitor cells and EPC-CFU showed no significant correlation.

CONCLUSION

The number of CD34 + progenitor cells positively correlates with FMD in young healthy women and is decreased by smoking.

Chronic smoking prevents amelioration of endothelial function in the course of the menstrual cycle

BACKGROUND

Smoking is the most important modifiable cardiovascular risk factor in young women. The aim of this study was to investigate whether tobacco use influences physiological changes in endothelial function during the menstrual cycle.

METHODS AND RESULTS

Flow-mediated dilation (FMD) and nitro-mediated dilation (NMD) were assessed in healthy smoking and non-smoking women, by high-resolution ultrasound at 3 time points during the menstrual cycle: at menstruation, in the mid-follicular phase, and in the mid-luteal phase. A total of 25 women (12 non-smokers, 13 smokers) completed the study protocol. FMD did not show differences between smoking and non-smoking women at menstruation and the mid-follicular phase. At the mid-luteal phase, however, FMD was significantly reduced in smoking when compared with non-smoking women. NMD did not differ between smoking and non-smoking women, nor between the different cycle phases.

CONCLUSIONS

In healthy women, smoking eliminates the physiological amelioration of endothelial function during the menstrual cycle. This study underlines the importance of an exact description of menstrual cycle phase and smoking status in studies investigating endothelial function in premenopausal women.

N-acetylcysteine improves microcirculatory flow during smoking: new effects of an old drug with possible benefits for smokers

BACKGROUND

Cigarette smoking provokes marked acute changes in the microcirculatory vasculature, including a reduced blood flow velocity. In accordance with the hypothesis that the reduced blood flow is due to an imbalance between pro-oxidants and oxidants, we recently showed that most of the reduction could be reversed by a high dose of vitamin C.

HYPOTHESIS

In the present work we tested the hypothesis that N-acetylcysteine, a mucolyticum and an antioxidant, may have an effect on the smoking-induced changes observed by vital capillary microscopy of the nailfold.

METHODS

In all, 37 healthy volunteers of both genders and with varied smoking habits were treated with N-acetylcysteine 200 mg t.i.d. for 2 weeks. In vivo investigation of the microcirculation by capillaroscopy was performed before and after treatment.

RESULTS

Treatment with N-acetylcysteine significantly reduced the smoking-induced relative decrease in capillary blood flow velocity in a group of volunteers with varied smoking habits (p = 0.0016). The preventive effect was clearly significant in smokers (p = 0.003).

CONCLUSION

Treatment with N-acetylcysteine has a positive impact on microcirculatory flow during smoking, particularly in habitual smokers.

Cigarette smoke inhibits adenine nucleotide hydrolysis by human platelets

Cigarette smoking is a recognized risk factor for cardiovascular diseases and has been implicated in the pathogenesis of atherosclerosis and thrombotic events. In athero-thrombotic diseases, the extracellular adenine nucleotides play an important role by triggering a range of effects such as the recruitment and activation of platelets, endothelial cell activation and vasoconstriction. NTPDase, a plasma membrane-bound enzyme, is the most relevant enzyme involved in the hydrolysis of extracellular tri- and di-phosphate nucleotides to adenosine monophosphate, which is further degraded by 5'ectonucleotidase to the anti-thrombotic and anti-inflammatory mediator adenosine. Thus, the preserved activity of these enzymes, regulating the extracellular concentrations of nucleotides, is critical in thromboregulatory functions. In the present in vitro study, performed on human platelets suspended in undiluted or diluted aqueous cigarette smoke extract (aCSE), we demonstrated that undiluted and 1 : 2 diluted aCSE is able to significantly reduce ADP hydrolysis (-24% and 12%, respectively) by intact human platelets. ATP degradation was also reduced (-31%) by undiluted aCSE. Conversely, aCSE did not alter platelet AMP hydrolysis. Results obtained by using N-acetylcysteine, a thiol-containing antioxidant, suggest that stable oxidants present in aCSE are responsible for the platelet NTPDase inhibition induced by aCSE. The decreased adenine nucleotide degradation could play a significant role in the extensive platelet activation and vascular inflammation observed in chronic smokers.

Acute effect of sidestream cigarette smoke extract on vascular endothelial function

Acute exposure to passive smoking adversely affects vascular function by promoting oxidative stress and endothelial dysfunction. However, it is not known whether tobacco sidestream (SS) smoke has a greater deleterious effect on the endothelium than non-tobacco SS smoke and whether these effects are related to nicotinic endothelial stimulation. To test these hypotheses, endothelial-dependent relaxation and superoxide anion production were assessed in isolated rat aortas incubated with tobacco SS smoke, non-tobacco SS smoke, or pure nicotine. Tobacco SS smoke decreased the maximal relaxation to acetylcholine (Ach) from 79 +/- 6% to 57 +/- 7.3% (% inhibition of phenylephrine-induced plateau, P < 0.001) and increased superoxide anion production from 31 +/- 9.7 to 116 +/- 24 count/10 sec/mg (P < 0.01, lucigenin-enhanced chemiluminescence technique). The non-tobacco SS smoke extract had no significant effect on the response to Ach but increased superoxide anion production in the aortic wall to 133 +/- 2 count/10 sec/mg (P < 0.001). Furthermore, concentration-response curves to Ach and superoxide production remained unaltered with nicotine (0.001, 0.01, or 0.1 mM). In conclusion, despite similar increases in vascular wall superoxide production with tobacco and non-tobacco SS smoke, only the tobacco SS smoke extracts affected endothelium-dependent vasorelaxation. Nicotine alone does not reproduce the effects seen with tobacco SS smoke, suggesting that the acute endothelial toxicity of passive smoking cannot simply be ascribed to a nicotine-dependent mechanism.

Smoking, smoking cessation and inflammatory markers in older Chinese men: The Guangzhou Biobank Cohort Study

AIMS

Smoking increases the risk of cardiovascular disease and inflammation plays a key role in the process of atherosclerosis. We therefore study the role of smoking and smoking cessation on the levels of inflammatory markers, C-reactive protein (CRP) and white blood cell (WBC) count, in older Chinese men.

METHODS

This cross-sectional analysis included 2999 men aged 50-85 years who received a medical check-up including measurement of fasting plasma vascular risk factors. Information on smoking status, socioeconomic and lifestyle factors was collected by standardized interview.

RESULTS

After adjustment for potential confounders, both CRP and WBC increased linearly across never, former and current smokers (both p<0.01). The odds ratios of elevated CRP and WBC (upper tertiles) were also increased across never, former and current smokers (both p<0.01). Dose-response relationships were observed among current smokers. Compared to current smokers, the odds ratios of elevated CRP and WBC and means of CRP and WBC declined with longer duration of smoking cessation (all p<0.01).

CONCLUSIONS

Smoking is associated with increased CRP and WBC levels, and smoking cessation is associated with the reduction of the increase, confirming the benefits of quitting. Inflammation may be a potential mechanism by which smoking promotes atherosclerotic disease.

Environmental risk factors for heart disease

In this review, we discuss current evidence linking environmental pollutants to cardiovascular disease (CVD). Extensive evidence indicates that environmental factors contribute to CVD risk, incidence, and severity. Migrant studies show that changes in the environment could substantially alter CVD risk in a genetically stable population. Additionally, CVD risk is affected by changes in nutritional and lifestyle choices. Recent studies in the field of environmental cardiology suggest that environmental toxins also influence CVD. Exposure to tobacco smoke is paradigmatic of such environmental risk and is strongly and positively associated with increased cardiovascular morbidity and mortality. In animal models of exposure, tobacco smoke induces endothelial dysfunction and prothrombotic responses and exacerbates atherogenesis and myocardial ischemic injury. Similar mechanism may be engaged by other pollutants or food constituents. Several large population-based studies indicate that exposure to fine or ultrafine particulate air pollution increases CVD morbidity and mortality, and the plausibility of this association is supported by data from animal studies. Exposure to other chemicals such as polyaromatic hydrocarbons, aldehydes, and metals has also been reported to elevate CVD risk by affecting atherogenesis, thrombosis, or blood pressure regulation. Maternal exposure to drugs, toxins, and infection has been linked with cardiac birth defects and premature CVD in later life. Collectively, the data support the notion that chronic environmental stress is an important determinant of CVD risk. Further work is required to assess the magnitude of this risk fully and to delineate specific mechanisms by which environmental toxins affect CVD.

Smoking, smoking cessation and aortic arch calcification in older Chinese: the Guangzhou Biobank Cohort Study

OBJECTIVE

To study the association between smoking, smoking cessation and aortic arc calcification (AAC) in an older Chinese population.

METHODS

A total of 3022 men and 7279 women aged 50-85 years were recruited and received a medical check-up including measurement of fasting plasma vascular risk factors. Two radiologists reviewed the posterior-anterior plain chest X-ray radiographs and assessed AAC together. Information on smoking status, socioeconomic and lifestyle factors was collected.

RESULTS

The crude prevalence of AAC in men (38.58%) was lower than that in women (41.37%). The adjusted odds ratios of AAC increased significantly across never, ex- and current smokers in both genders. Dose-response relationships were observed among current smokers for smoking amount (cigarettes/day), smoking duration (years) and cigarette pack-years in both genders (all p<0.01). The odds ratios decreased significantly (p=0.018) with longer duration of quitting in light ex-smoking men (<23.5 pack-years) but showed no beneficial effect (p=0.72) for heavy ex-smokers (>or=23.5 pack-years).

CONCLUSION

Smoking increased the risk of AAC in Chinese, while smoking cessation decreased the risk only in male light ex-smokers. Chest X-ray is a cheap and simple method to detect AAC, which should be an important warning signal for immediate smoking cessation.

Isogentisin--a novel compound for the prevention of smoking-caused endothelial injury

The best strategy in the fight against tobacco-induced diseases is prevention. However, more than one billion people around the world are smokers. Most of these people will develop or already suffer from tobacco-induced diseases. In this project, we screened 22 natural alpine plant extracts for their potential to protect human vascular endothelial cells from cigarette smoke-induced cell damage. Extracts from Gentiana lutea (Yellow Gentian) proved to be effective, and were therefore subjected to bio-guided fractionation. Although our analyses suggest that G. lutea contains several active principles, fractions containing isogentisin (1,3-dihydroxy-7-methoxyxanthone), and pure isogentisin, were most effective. In experiments addressing the nature of the mechanism of protection, we were able to show that isogentisin does not directly interfere with cigarette smoke chemicals. Addition of isogentisin to the cells as long as 4.5h after exposure to cigarette smoke chemicals protected endothelial cells from cell death. Finally, detailed analyses of intracellular oxidative stress and protein oxidation suggest that isogentisin promotes cell survival by activating cellular repair functions.

Fetal and neonatal nicotine exposure differentially regulates vascular contractility in adult male and female offspring

Epidemiologic studies suggest that prenatal exposure to maternal cigarette smoking is associated with an increased risk of elevated blood pressure in postnatal life. The present study was designed to test the hypothesis that fetal and neonatal nicotine exposure increased vascular contractility in adult offspring. Nicotine was administered to pregnant rats via s.c. osmotic minipumps throughout gestation and up to 10 days after delivery. Aortas were isolated from adult male and female offspring at the age of 3 months old. Nicotine significantly increased KCl- and norepinephrine-induced contractions of the aorta in male, but not female, offspring. Inhibition of endothelial nitric oxide synthase (eNOS) with N(G)-nitro-L-arginine (L-NNA) significantly increased norepinephrine-induced contractions in control male offspring but showed no effect in nicotine-treated male offspring. In the presence of L-NNA, there was no significant difference in norepinephrine-induced contractions between control and nicotine-treated males. In contrast, nicotine caused a significant increase in L-NNA-mediated potentiation of norepinephrine-induced contractions in female offspring. Nicotine had no effect on sodium nitroprusside-induced endothelium-independent relaxations of aortas from either male or female offspring. However, it decreased endothelium-dependent relaxations induced by acetylcholine in male offspring but increased them in females. There were no differences in eNOS protein levels in aortas between the control and nicotine-treated animals in either male or female offspring. The results suggest that fetal and neonatal nicotine exposure alters vascular functions in adult offspring in a gender-specific manner, which may lead to an increased risk of cardiovascular dysfunction in later life.

The pathophysiology of cigarette smoking and cardiovascular disease: an update

Cigarette smoking (CS) continues to be a major health hazard, and it contributes significantly to cardiovascular morbidity and mortality. Cigarette smoking impacts all phases of atherosclerosis from endothelial dysfunction to acute clinical events, the latter being largely thrombotic. Both active and passive (environmental) cigarette smoke exposure predispose to cardiovascular events. Whether there is a distinct direct dose-dependent correlation between cigarette smoke exposure and risk is debatable, as some recent experimental clinical studies have shown a non-linear relation to cigarette smoke exposure. The exact toxic components of cigarette smoke and the mechanisms involved in CS-related cardiovascular dysfunction are largely unknown, but CS increases inflammation, thrombosis, and oxidation of low-density lipoprotein cholesterol. Recent experimental and clinical data support the hypothesis that cigarette smoke exposure increases oxidative stress as a potential mechanism for initiating cardiovascular dysfunction.

Impairment of nitric oxide synthase-dependent dilatation of cerebral arterioles during infusion of nicotine

The effects of nicotine on nitric oxide synthase (NOS)-dependent reactivity of cerebral arterioles remain uncertain. Our first goal was to examine whether infusion of nicotine alters NOS-dependent reactivity of cerebral arterioles. Our second goal was to examine the mechanisms that may account for the effects of nicotine on cerebral arterioles. We measured the diameter of pial arterioles to NOS-dependent (ADP and acetylcholine) and NOS-independent (nitroglycerin) agonists before and after the infusion of nicotine (2 microg x kg(-1) x min(-1) iv for 30 min, followed by a maintenance dose of 0.35 microg x kg(-1) x min(-1)). ADP- and acetylcholine-induced vasodilatation was impaired after the infusion of nicotine. In contrast, nicotine did not alter vasodilatation to nitroglycerin. Next, we examined whether the impaired responses of pial arterioles during infusion of nicotine may be related to oxygen radicals. We found that application of superoxide dismutase or tetrahydrobiopterin during infusion of nicotine could prevent impaired NOS-dependent vasodilatation. Thus acute exposure of cerebral vessels to nicotine specifically impairs NOS-dependent dilatation via the production of oxygen radicals possibly related to an alteration in the utilization of tetrahydrobiopterin.

Acute and chronic treatment with nicotine impairs reactivity of arterioles in response to activation of potassium channels

Although acute and chronic treatment with nicotine impairs nitric oxide synthase-dependent responses of large and small blood vessels, the effect of nicotine on other vasodilator pathways remains uncertain. The goal of the current study was to determine effects of nicotine on dilatation of arterioles to activation of ATP-sensitive potassium channels. Reactivity of cheek pouch arterioles ( approximately 50 microm) was measured during acute (1-2 h) and chronic (2-to 3-week) exposure to nicotine in response to aprikalim, cromakalim, and nitroglycerin. Acute treatment with nicotine impaired dilatation of arterioles in response to aprikalim and cromakalim but not nitroglycerin. Aprikalim and cromakalim (1.0 microM) dilated arterioles by 37 +/- 5% and 30 +/- 3%, respectively, before, but by only 21 +/- 4% and 16 +/- 3%, respectively, after infusion of nicotine (p < 0.05). Chronic exposure to nicotine did not alter vasodilatation to nitroglycerin but impaired vasodilatation to aprikalim and cromakalim. In vehicle-treated hamsters, aprikalim and cromakalim (1.0 microM) dilated arterioles by 28 +/- 1% and 32 +/- 3%, respectively. However, in nicotine-treated hamsters aprikalim and cromakalim (1.0 microM) dilated arterioles by only 3 +/- 1% and 13 +/- 1%, respectively. Next, the role of superoxide anion in impaired responses of arterioles to aprikalim and cromakalim during acute infusion of nicotine was examined. Treatment with superoxide dismutase attenuated the effects of nicotine on aprikalim and cromakalim. Thus, acute and chronic exposure to nicotine has profound affects on vasodilatation to activation of ATP-sensitive potassium channels, which may be mediated by superoxide anion.