Dysfunctional endothelial nitric oxide biosynthesis in healthy smokers with impaired endothelium-dependent vasodilatation

Evidence of premature vascular dysfunction in young adults who regularly use e-cigarettes and the impact of usage length

BACKGROUND

Electronic (e-) cigarettes are increasingly popular tobacco products on the US market. Traditional tobacco products are known to cause vascular dysfunction, one of the earliest indicators of cardiovascular disease (CVD) development. However, little is known about the effect of regular e-cigarette use on vascular function. The purpose of this study was to investigate the impact of regular e-cigarette use on vascular function and cardiovascular health in young, healthy adults.

METHODS

Twenty-one regular users of e-cigarettes (ECU) and twenty-one demographically matched non-users (NU) completed this study. Vascular health was assessed in the cutaneous microcirculation through different reactivity tests to evaluate overall functionality, endothelium-dependent vasodilation (EDD), and endothelium-independent vasodilation (EID). Macrovascular function was assessed using flow-mediated dilation (FMD).

RESULTS

Our results suggest that regular users of e-cigarettes present with premature microvascular impairment when compared to non-users. Specifically, they exhibit lower hyperemic (p = 0.003), thermal (p = 0.010), and EDD (p = 0.004) responses. No differences in EID between the groups were identified. We also identified that individuals who use e-cigarettes for longer than 3 years also present with systemic manifestations, as observed by significantly reduced macrovascular (p = 0.002) and microvascular (p ≤ 0.044) function.

CONCLUSIONS

Our novel data suggests that young, apparently healthy, regular users of e-cigarettes present with premature vascular dysfunction in the microcirculation when compared to non-users. We have also identified systemic vascular dysfunction affecting both the micro and macrovasculature in those young individuals who used e-cigarettes for longer than 3 years. Taken together, these findings associate regular e-cigarette use with premature vascular dysfunctions and adverse cardiovascular outcomes.

Documento de consenso sobre tabaquismo y riesgo vascular

Consensus statement on smoking and vascular risk About 22% of the Spanish population are daily smokers. Men are more likely to smoke than women. In Spain, women between 15-25 years of age smoke as much or more than men. Every smoker should be assessed for: physical dependence on nicotine (Fagerström test), social and psychological dependence (Glover Nilsson test), level of motivation to quit (Richmond test), probability of therapy success (Henri-Mondor and Michael-Fiore tests), and stage of behavioral change development (Prochaska and DiClementi). Advice on smoking cessation is highly cost-effective and should always be provided. Smoking is an enhancer of cardiovascular risk because it acts as a pathogen agent in the development of arteriosclerosis and is associated with ischemic heart disease, stroke, and peripheral artery disease. Smoking increases the risk of chronic lung diseases (COPD) and is related to cancers of the lung, female genitalia, larynx, oropharynx, bladder, mouth, esophagus, liver and biliary tract, and stomach, among others. Combined oral contraceptives should be avoided in women smokers older than 35 years of age due to the risk of thromboembolism. In smoking cessation, the involvement of physicians, nurses, psychologists, etc. is important, and their multidisciplinary collaboration is needed. Effective pharmacological treatments for smoking cessation are available. Combined treatments are recommended when smoker's dependence is high. For individuals who are unable to quit smoking, a strategy based on tobacco damage management with a total switch to smokeless products could be a less dangerous alternative for their health than continuing to smoke.

Cigarette smoking and air pollution exposure and their effects on cardiovascular diseases

Cardiovascular disease (CVD) has no socioeconomic, topographical, or sex limitations as reported by the World Health Organization (WHO). The significant drivers of CVD are cardio-metabolic, behavioral, environmental, and social risk factors. However, some significant risk factors for CVD (e.g., a pitiable diet, tobacco smoking, and a lack of physical activities), have also been linked to an elevated risk of cardiovascular disease. Lifestyles and environmental factors are known key variables in cardiovascular disease. The familiarity with smoke goes along with the contact with the environment: air pollution is considered a source of toxins that contribute to the CVD burden. The incidence of myocardial infarction increases in males and females and may lead to fatal coronary artery disease, as confirmed by epidemiological studies. Lipid modification, inflammation, and vasomotor dysfunction are integral components of atherosclerosis development and advancement. These aspects are essential for the identification of atherosclerosis in clinical investigations. This article aims to show the findings on the influence of CVD on the health of individuals and human populations, as well as possible pathology and their involvement in smoking-related cardiovascular diseases. This review also explains lifestyle and environmental factors that are known to contribute to CVD, with indications suggesting an affiliation between cigarette smoking, air pollution, and CVD.

Cigarette Smoke-Induced Reactive Oxygen Species Formation: A Concise Review

Smoking is recognized as a significant risk factor for numerous disorders, including cardiovascular diseases, respiratory conditions, and various forms of cancer. While the exact pathogenic mechanisms continue to be explored, the induction of oxidative stress via the production of excess reactive oxygen species (ROS) is widely accepted as a primary molecular event that predisposes individuals to these smoking-related ailments. This review focused on how cigarette smoke (CS) promotes ROS formation rather than the pathophysiological repercussions of ROS and oxidative stress. A comprehensive analysis of existing studies revealed the following key ways through which CS imposes ROS burden on biological systems: (1) ROS, as well as radicals, are intrinsically present in CS, (2) CS constituents generate ROS through chemical reactions with biomolecules, (3) CS stimulates cellular ROS sources to enhance production, and (4) CS disrupts the antioxidant system, aggravating the ROS generation and its functions. While the evidence supporting these mechanisms is chiefly based on in vitro and animal studies, the direct clinical relevance remains to be fully elucidated. Nevertheless, this understanding is fundamental for deciphering molecular events leading to oxidative stress and for developing intervention strategies to counter CS-induced oxidative stress.

Cigarette Smoke-Induced Respiratory Response: Insights into Cellular Processes and Biomarkers

Cigarette smoke (CS) poses a significant risk factor for respiratory, vascular, and organ diseases owing to its high content of harmful chemicals and reactive oxygen species (ROS). These substances are known to induce oxidative stress, inflammation, apoptosis, and senescence due to their exposure to environmental pollutants and the presence of oxidative enzymes. The lung is particularly susceptible to oxidative stress. Persistent oxidative stress caused by chronic exposure to CS can lead to respiratory diseases such as chronic obstructive pulmonary disease (COPD), pulmonary fibrosis (PF), and lung cancer. Avoiding exposure to environmental pollutants, like cigarette smoke and air pollution, can help mitigate oxidative stress. A comprehensive understanding of oxidative stress and its impact on the lungs requires future research. This includes identifying strategies for preventing and treating lung diseases as well as investigating the underlying mechanisms behind oxidative stress. Thus, this review aims to investigate the cellular processes induced by CS, specifically inflammation, apoptosis, senescence, and their associated biomarkers. Furthermore, this review will delve into the alveolar response provoked by CS, emphasizing the roles of potential therapeutic target markers and strategies in inflammation and oxidative stress.

Cigarette smoking and erectile dysfunction: an updated review with a focus on pathophysiology, e-cigarettes, and smoking cessation

Introduction

Cigarette smoking has major health implications and causes substantial damage to all organ systems. Approximately one-third of men are active smokers worldwide, and most men are unaware that cigarette smoking can contribute to erectile dysfunction (ED).

Objectives

This article aims to provide a comprehensive overview of research conducted on cigarette smoking and ED, with a particular focus on pathophysiology, electronic cigarettes (e-cigarettes), and smoking cessation.

Methods

A manual literature search was conducted on all research conducted on cigarette smoking and ED up to October 2022.

Results

Substantial evidence is now available showing that past and current cigarette smoking has dose-dependent associations with ED in studies controlling for age and important health comorbidities. Cigarette smoke contains nicotine, carbon monoxide, oxidant chemicals, and metals that can damage the endothelium and disrupt erectile processes. For current smokers, smoking abstinence can strengthen the endothelium and reverse diminished erectile function. The effect of e-cigarettes on endothelial damage and ED remains largely untested. E-cigarettes expose users to fine and ultrafine particles and toxins that can increase risk of cardiovascular injury, but these acute effects appear less potent than conventional cigarettes (long-term cardiovascular effects are still unknown). E-cigarettes are therefore likely to have less harmful effects on ED than conventional cigarettes.

Conclusions

Smoking cessation programs that focus on nicotine replacement therapy (transdermal patches, gum, or inhalers), behavioral counseling, social support, and education programs can be effective approaches to ED treatment in active smokers. Temporarily transferring from regular cigarettes to e-cigarettes—which transmit some of the same carcinogens as conventional cigarettes and are likely to have some long-term cardiovascular effects that disrupt erectile function—might also be useful for long-term smoking cessation and treatment of ED.

Effect of Aerobic Exercise on Arterial Stiffness in Individuals with Different Smoking Statuses

This study aimed to investigate the immediate effects of acute bout of aerobic exercise on arterial stiffness in individuals with different smoking statuses. A total of 940 male individuals (mean age of 36.82±7.76 years) in the Kailuan study cohort were selected to participate in the fifth National Physical Fitness Monitoring. All participants completed measurements of brachial - ankle pulse wave velocity (baPWV) before and after twice-quantitative cycle ergometer exercise. Four groups were defined: (1) non-smokers (n=231), (2) former smokers (n=165), (3) light smokers (1-10 cigarettes/day, n=254), (4) heavy smokers (>10 cigarettes/day, n=290). Generalized linear models were established to analyze between-group differences in the change in baPWV before and after acute aerobic exercise in individuals with different smoking statuses. Overall, after acute aerobic exercise, baPWV was immediately decreased significantly (-33.55 cm/s [95% CI, - 39.69 to -27.42]). Compared with non-smokers, former smokers, light smokers, and heavy smokers showed a greater decrease in baPWV (-12.17 cm/s [95%CI, - 30.08 to 5.75], - 18.43 cm/s [95%CI, -34.69 to - 2.16], and -22.46 cm/s [95%CI, - 38.39 to - 6.54]) respectively. There is a transient decrease in baPWV in individuals with different smoking statuses. Compared with non-smokers, baPWV decreased more significantly in light and heavy smokers.

Chronic E-Cigarette Use Impairs Endothelial Function on the Physiological and Cellular Levels

BACKGROUND

The harmful vascular effects of smoking are well established, but the effects of chronic use of electronic cigarettes (e-cigarettes) on endothelial function are less understood. We hypothesized that e-cigarette use causes changes in blood milieu that impair endothelial function.

METHODS

Endothelial function was measured in chronic e-cigarette users, chronic cigarette smokers, and nonusers. We measured effects of participants' sera, or e-cigarette aerosol condensate, on NO and H2O2 release and cell permeability in cultured endothelial cells (ECs).

RESULTS

E-cigarette users and smokers had lower flow-mediated dilation (FMD) than nonusers. Sera from e-cigarette users and smokers reduced VEGF (vascular endothelial growth factor)-induced NO secretion by ECs relative to nonuser sera, without significant reduction in endothelial NO synthase mRNA or protein levels. E-cigarette user sera caused increased endothelial release of H2O2, and more permeability than nonuser sera. E-cigarette users and smokers exhibited changes in circulating biomarkers of inflammation, thrombosis, and cell adhesion relative to nonusers, but with distinct profiles. E-cigarette user sera had higher concentrations of the receptor for advanced glycation end products (RAGE) ligands S100A8 and HMGB1 (high mobility group box 1) than smoker and nonuser sera, and receptor for advanced glycation end product inhibition reduced permeability induced by e-cigarette user sera but did not affect NO production.

CONCLUSIONS

Chronic vaping and smoking both impair FMD and cause changes in the blood that inhibit endothelial NO release. Vaping, but not smoking, causes changes in the blood that increase microvascular endothelial permeability and may have a vaping-specific effect on intracellular oxidative state. Our results suggest a role for RAGE in e-cigarette-induced changes in endothelial function.

Impact of Smoking on Visual Field Progression in a Long-term Clinical Follow-up

PURPOSE

To investigate the effect of smoking on rates of progressive visual field (VF) damage over time in glaucoma.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Five hundred eleven eyes of 354 patients with glaucoma followed up from multicenter glaucoma registries.

METHODS

In this longitudinal study, 354 patients with primary open-angle glaucoma with a minimum of 3 years of follow-up and 5 VF tests were enrolled from the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study. Univariate and multivariate linear mixed models were used to investigate the effects of smoking on rates of 24-2 VF mean deviation loss. Visual field progression was defined using pointwise linear and significant negative VF mean deviation loss. Logistic regression was used to identify baseline factors and whether different levels of smoking intensity were associated with VF progression. Kaplan-Meier survival analysis and the log-rank test were used to compare the cumulative risk ratio of progression between smoker and never smoker groups.

MAIN OUTCOME MEASURES

Visual field progression.

RESULTS

Five hundred eleven eyes of 354 patients were included over the median follow-up of 12.5 years. Median baseline age was 64.8 years. Of the 354 patients, 124 (35%) were Black, and 149 (42.1%) and 168 (59.8%) had reported a history of smoking or alcohol consumption, respectively. In a multivariate model, higher smoking intensity was associated with faster VF loss (coefficient, -0.05 decibels (dB)/year per 10 pack-years; 95% confidence interval [CI], -0.08 to -0.01 dB/year per 10 pack-years; P = 0.010). Developing VF progression in eyes of heavy smokers (≥ 20 pack-years) was 2.2 times more than in eyes of patients without smoking history (odds ratio, 2.21; 95% CI, 1.02-4.76; P = 0.044). Statistically significant differences were found between heavy smokers (≥ 20 pack-years) and never smokers by Kaplan-Meier analysis (P = 0.011, log-rank test).

CONCLUSIONS

Heavy smokers are more likely to sustain VF loss in eyes with glaucoma. The prospective longitudinal design of this study supports the hypothesis that levels of smoking may be a significant predictor for glaucoma progression. Additionally, this information can be used for clinically relevant tobacco prevention and intervention messages.

Effects of Smoking on Optic Nerve Head Microvasculature Density in Glaucoma

PRCIS

Decreased superficial whole image capillary density was observed in open angle glaucoma (OAG) patients with high smoking intensity.

PURPOSE

To investigate the effects of smoking on optic nerve head capillary density measured by optical coherence tomography angiography in patients with OAG.

METHODS

In this retrospective cross-sectional study, perimetric and preperimetric glaucoma patients enrolled in the Diagnostic Innovations in Glaucoma Study (DIGS) with optical coherence tomography angiography follow-up were included. Univariable and multivariable linear mixed analysis were performed to determine the effects of different variables on the superficial whole image capillary density.

RESULTS

A total of 432 eyes of 271 glaucoma patients comprising 63 preperimetric (106 eyes) and 208 perimetric OAG (326 eyes) were included. A history of tobacco consumption was reported in 105 (38.8%). Among smokers, mean (95% confidence interval) smoking intensity was 12.8 (10.2, 15.5) pack-years. After adjusting for age, glaucoma severity and other confounders, each 10 pack-year increase in smoking intensity (95% confidence interval) was associated with -0.54 (-1.06, -0.02) % lower whole image capillary density ( P =0.041).

CONCLUSIONS

Smoking intensity is associated with reduced optic nerve vessel density in glaucoma.

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.

Comparable Impairment of Vascular Endothelial Function by a Wide Range of Electronic Nicotine Delivery Devices

INTRODUCTION

Electronic nicotine delivery systems (ENDS; ie, vaping devices) such as e-cigarettes, heated tobacco products, and newer coil-less ultrasonic vaping devices are promoted as less harmful alternatives to combustible cigarettes. However, their cardiovascular effects are understudied. We investigated whether exposure to aerosol from a wide range of ENDS devices, including a new ultrasonic vaping device, impairs endothelial function.

AIMS AND METHODS

We measured arterial flow-mediated dilation (FMD) in rats (n = 8/group) exposed to single session of 10 cycles of pulsatile 5-second exposure over 5 minutes to aerosol from e-liquids with and without nicotine generated from a USONICIG ultrasonic vaping device, previous generation e-cigarettes, 5% nicotine JUUL pods (Virginia Tobacco, Mango, Menthol), and an IQOS heated tobacco product; with Marlboro Red cigarette smoke and clean air as controls. We evaluated nicotine absorption and serum nitric oxide levels after exposure, and effects of different nicotine acidifiers on platelet aggregation.

RESULTS

Aerosol/smoke from all conditions except air significantly impaired FMD. Serum nicotine varied widely from highest in the IQOS group to lowest in USONICIG and previous generation e-cig groups. Nitric oxide levels were not affected by exposure. Exposure to JUUL and similarly acidified nicotine salt e-liquids did not affect platelet aggregation rate. Despite lack of heating coil, the USONICIG under airflow conditions heated e-liquid to ~77°C.

CONCLUSIONS

A wide range of ENDS, including multiple types of e-cigarettes with and without nicotine, a heated tobacco product, and an ultrasonic vaping device devoid of heating coil, all impair FMD after a single vaping session comparably to combusted cigarettes.

IMPLICATIONS

The need to understand the cardiovascular effects of various ENDS is of timely importance, as we have seen a dramatic increase in the use of these products in recent years, along with the growing assumption among its users that these devices are relatively benign. Our conclusion that a single exposure to aerosol from a wide range of ENDS impairs endothelial function comparably to cigarettes indicates that vaping can cause similar acute vascular functional impairment to smoking and is not a harmless activity.

Pathophysiologic Mechanisms of Tobacco Smoke Producing Atherosclerosis

INTRODUCTION

Despite the convincing epidemiologic association between smoking and vascular disease, the pathophysiologic mechanisms by which smoking initiates and contributes to the progression of atherosclerosis remain incompletely understood. A precise dose-dependent correlation has never been demonstrated, suggesting that the biological relationship is complex and influenced by individual genetic and possibly environmental factors. Although endothelial dysfunction and intimal damage appear to be central to atherogenesis, how tobacco products cause this effect has not been established. The purpose of this review is to describe the current state of knowledge of the main pathophysiologic pathways of how tobacco smoking abets atherosclerosis. Constituents of Tobacco Smoke: Tobacco combustion produces a mixture of organic substances. derived from burning organic materials. The predominant gaseous phase constituents include carbon monoxide, acetaldehyde, formaldehyde, acrolein, and other carbonyls, as well as nicotine and tobacco-specific nitrosamines. Potential Pathophysiologic Mechanisms: Smoking-induced changes in coronary vasomotor tone, platelet activation, and endothelial integrity are major components of both the development of atherosclerosis and its clinical presentation. Smoking may initiate and accelerate the progression of atherosclerosis by injuring the vascular intima. Other potential mechanisms include intimal damage and endothelial dysfunction, oxidative stress and injury, thrombosis, lipid abnormalities, and inflammation.

CONCLUSION

Smoking tobacco products contributes measurably to the incidence of acute vascular events and chronic disease. The causative compound, the exact mechanism of injury, and whether the atherogenic effect is modifiable are not known.

Protective effect of gallic acid on nicotine-induced testicular toxicity in mice

Background and purpose

Nicotine is an alkaloid found in many nutrients and tobacco that can cause infertility in men. Gallic acid is a powerful antioxidant that possesses antimutagenic and anticancer activities. This study aimed to determine the potential protective effect of gallic acid against nicotine-induced testicular toxicity in male mice.

Experimental approach

In this in vivo study, forty-eight mice were equally divided into eight groups intraperitoneally receiving normal saline (control), nicotine (0.6 mg/kg), gallic acid (5, 10, and 15 mg/kg), and gallic acid (5, 10, and 15 mg/kg) plus nicotine. Nicotine was injected intraperitoneally for 14 days and gallic acid was administered concomitantly with nicotine and continued for 7 days later. Then, body and testicular weights, the sperm parameters (viability, number, motility, and morphology of sperm), and testicular histology were evaluated. Also, serum levels of nitric oxide, total antioxidant, superoxide dismutase, malondialdehyde, and testosterone were measured.

Findings/Results

The results showed that the administration of nicotine significantly reduced testis and body weight, sperm count, viability, normal morphology and motility, seminiferous tubules diameter, testosterone levels, serum levels of total antioxidants, and superoxide dismutase compared to the control group (P < 0.05). It also significantly increased the level of nitric oxide and malondialdehyde (P < 0.05). Increasing the dose of gallic acid along with nicotine significantly increased body weight, sperm count, viability, normal morphology and motility, the diameter of seminiferous, testosterone concentration, total antioxidant levels (P < 0.05). This combination also significantly decreased malondialdehyde and nitric oxide levels compared to the nicotine-receiving group (P < 0.05).

Conclusion and implications

Gallic acid had a protective effect on nicotine-induced testicular toxicity in mice. It can neutralize the harmful effect of nicotine on male fertility in smokers.

Tumour necrosis factor inhibitors reduce aortic stiffness progression in patients with long-standing rheumatoid arthritis

BACKGROUND

Aortic stiffness index (AoSI) has to be considered a proxy outcome measure in patients with rheumatoid arthritis (RA). The aim of this study was to comparatively describe AoSI progression in two groups of RA patients on long-term treatment with conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs) with or without tumour necrosis factor inhibitors (TNFi).

METHODS

AoSI was evaluated by Doppler echocardiography at the level of the aortic root, using a two-dimensional guided M-mode evaluation. Eligible participants were assessed at baseline and after 12 months. Changes in serum lipids, glucose and arterial blood pressure were assessed. All patients who did not change DMARD treatment during follow-up were consecutively selected for this study.

RESULTS

We included 107 (64 TNFi and 43 csDMARDs) RA patients. Most patients (74%) were in remission or low disease activity and had some CVD risk factors (45.8% hypertension, 59.8% dyslipidaemia, 45.3% smoking). The two groups did not differ significantly for baseline AoSI (5.95±3.73% vs 6.08±4.20%, p=0.867). Follow-up AoSI was significantly increased from baseline in the csDMARDs group (+1.00%; p<0.0001) but not in the TNFi group (+0.15%, p=0.477). Patients on TNFi had significantly lower follow-up AoSI from baseline than the csDMARDs group (-1.02%, p<0.001; ANCOVA corrected for baseline AoSI, age and systolic blood pressure). Furthermore, follow-up AoSI was significantly lower in TNFi than in csDMARDs users with an increasing number of CVD risk factors.

CONCLUSION

Long-term treatment with TNFi was associated with reduced aortic stiffness progression in patients with established RA and several CVD risk factors.

Update on smoking. Alternatives for the management of patients with cardiovascular risk

Smoking is the leading cause of morbidity and mortality worldwide and is clearly involved as a cardiovascular risk factor. Smoking has different effects on the cardiovascular system, such as a decrease in nitric oxide, increased inflammatory response, increased adhesion of pro-atherogenic molecules, lipid disturbances, generation of oxidative stress and endothelial dysfunction as can be shown in different biomarkers modifications. Despite the aids currently available for smoking cessation, many smokers are unwilling or unable to achieve this. So alternative tools with potential harm reduction, such as non-combustion tobacco products, could be an option due to the better results they had shown on cardiovascular risk factors. This has led these devices to be taken into account as a risk-modifying tobacco product according to the FDA.

Habitual cannabis use is associated with altered cardiac mechanics and arterial stiffness, but not endothelial function in young healthy smokers

Cigarette smoking is among the most detrimental behaviors to cardiovascular health, resulting in arterial stiffening, endothelial dysfunction, and structural/functional alterations to the myocardium. Similar to cigarettes, cannabis is commonly smoked, and next to alcohol, is the most commonly used recreational substance in the world. Despite this, little is known about the long-term cardiovascular effects of smoking cannabis. This study explored the associations of cardiovascular structure and function with cannabis use in ostensibly healthy young participants (n = 35). Using echocardiography, carotid-femoral pulse wave velocity (cfPWV), and brachial flow-mediated dilation (FMD), we performed a cross-sectional assessment of cardiovascular function in cannabis users (n = 18) and controls (n = 17). There were no differences in cardiac morphology or traditional resting measures of systolic or diastolic function between cannabis users and controls (all P > 0.05), whereas cannabis users demonstrated reduced peak apical rotation compared with controls (cannabis users: 5.5 ± 3.8, controls: 9.6 ± 1.5; P = 0.02). Cannabis users had higher cfPWV compared with controls (cannabis users: 5.8 ± 0.6 m/s, controls: 5.3 ± 0.7 m/s; P = 0.05), whereas FMD was similar between cannabis users and controls (cannabis users: 8.3 ± 3.3%, controls: 6.8 ± 3.6%; P = 0.7). Young, healthy, and cannabis users demonstrate altered cardiac mechanics and greater aortic stiffness. Further studies should explore causal links between cannabis smoking and altered cardiovascular function.NEW & NOTEWORTHY Recreational cannabis is the most widely used substance in the world, other than alcohol. Yet, the effects of cannabis use on cardiovascular function and health are not well understood. Our cross-sectional data demonstrate that young, ostensibly healthy cannabis users have greater arterial stiffness and altered cardiac mechanics compared to nonusers. These findings suggest that cannabis users may be at greater risk of the development of future cardiovascular disease.

Long-term electronic cigarette exposure induces cardiovascular dysfunction similar to tobacco cigarettes: role of nicotine and exposure duration

Electronic cigarette (e-cig) vaping (ECV) has been proposed as a safer alternative to tobacco cigarette smoking (TCS); however, this remains controversial due to a lack of long-term comparative studies. Therefore, we developed a chronic mouse exposure model that mimics human vaping and allows comparison with TCS. Longitudinal studies were performed to evaluate alterations in cardiovascular function with TCS and ECV exposure durations of up to 60 wk. For ECV, e-cig liquid with box-mod were used and for TCS, 3R4F-cigarettes. C57/BL6 male mice were exposed 2 h/day, 5 days/wk to TCS, ECV, or air control. The role of vape nicotine levels was evaluated using e-cig-liquids with 0, 6, or 24 mg/mL nicotine. Following 16-wk exposure, increased constriction to phenylephrine and impaired endothelium-dependent and endothelium-independent vasodilation were observed in aortic segents, paralleling the onset of systemic hypertension, with elevations in systemic vascular resistance. Following 32 wk, TCS and ECV induced cardiac hypertrophy. All of these abnormalities further increased out to 60 wk of exposure, with elevated heart weight and aortic thickness along with increased superoxide production in vessels and cardiac tissues of both ECV and TCS mice. While ECV-induced abnormalities were seen in the absence of nicotine, these occurred earlier and were more severe with higher nicotine exposure. Thus, long-term vaping of e-cig can induce cardiovascular disease similar to TCS, and the severity of this toxicity increases with exposure duration and vape nicotine content.NEW & NOTEWORTHY A chronic mouse exposure model that mimics human e-cigarette vaping and allows comparison with tobacco cigarette smoking was developed and utilized to perform longitudinal studies of alterations in cardiovascular function. E-cigarette exposure led to the onset of cardiovascular disease similar to that with tobacco cigarette smoking. Impaired endothelium-dependent and endothelium-independent vasodilation with increased adrenergic vasoconstriction were observed, paralleling the onset of systemic hypertension and subsequent cardiac hypertrophy. This cardiovascular toxicity was dependent on exposure duration and nicotine dose.

Effect of smoking on the macula and optic nerve integrity using optical coherence tomography angiography

OBJECTIVE

To investigate the effect of chronic smoking on the macula and optic nerve integrity using optical coherence tomography angiography (OCTA).

METHODS

This prospective, comparative study involved the right eyes of 160 healthy subjects (80 smokers group, and 80 control group). OCTA scanning was performed for all subjects. All macular subfields thickness, peripapillary retinal nerve fiber layer (RNFL) thickness, macular ganglion cell complex (GCC) thickness, superficial and deep macular vessel density, foveal avascular zone (FAZ) area, and the macular outer retina flow area, were measured and analyzed.

RESULTS

The thickness of some macular subfields, inferior GCC, and RNFL was statistically significantly lower in the smokers' group (p < 0.05). The FAZ area was 0.409 ± 0.048 mm² in the smokers' group and 0.327 ± 0.055 mm² in the control group (p < 0.001). The superficial foveal VD was 31.35 ± 5.79% in the smokers' group and 33.63 ± 4.78% in the control group (p = 0.06). The deep foveal VD was 39.38 ± 4.56% in the smokers' group and 34.15 ± 6.57% in the control group (p ≤ 0.001). The superficial and deep parafoveal VD was 52.09 ± 4.56% and 59.99 ± 2.25% respectively in the smokers' group, and 54.75 ± 2.30% and 55.58 ± 4.69% respectively in the control group (p < 0.05). The macular outer retina flow area was 1.29 ± 0.12 mm² in the smokers' group and 1.16 ± 0.11 mm² in the control group (p < 0.001).

CONCLUSION

Chronic smoking affected the integrity of the macula and optic nerve. It decreased the macular VD, enlarged the FAZ, and increased outer retinal flow area.

Habitual cigarette smoking attenuates shear-mediated dilation in the brachial artery but not in the carotid artery in young adults

In the present study, we hypothesized that habitual cigarette smoking attenuates endothelial function in the cerebral circulation as well as that of the peripheral circulation in young adults. To test this hypothesis, we measured cerebrovascular and peripheral flow‐mediated dilation (FMD) in young smokers and nonsmokers in the present study. Ten healthy nonsmokers and 10 smokers participated in the study. We measured blood velocity and diameter in the brachial artery and internal carotid artery (ICA) using Doppler ultrasound. We identified shear‐mediated dilation in the brachial artery and ICA by the percentage change in peak diameter during hyperemia stimulation (reactive hyperemia and hypercapnia). We measured the baseline diameter and the shear rate area under the curve from the onset of hyperemia to peak dilation in the brachial artery and ICA, finding the measurements of the smokers and those of the nonsmokers did not differ (p > .05). In contrast to brachial FMD (5.07 ± 1.79% vs. 7.92 ± 3.01%; smokers vs. nonsmokers, p = .019), FMD in the ICA was not attenuated in the smokers compared with that of the nonsmokers (5.46 ± 2.32% vs. 4.57 ± 2.70%; p = .442). These findings indicate that in young healthy smokers, cerebral endothelial function was preserved, and the response of cerebral endothelial function to smoking was different from that of peripheral vasculature.

Association of Carboxyhemoglobin Levels with Peripheral Arterial Disease in Chronic Smokers Managed at Dr George Mukhari Academic Hospital

Chronic cigarette smokers (CCS) are known to have elevated levels of carboxyhemoglobin (COHb). However, it is not known whether increased levels of COHb are associated with endothelial dysfunction (ED), and therefore the development of peripheral arterial disease (PAD). The aim of the study was to investigate the association of blood COHb and plasma nitric oxide (NO) levels, and whether it is an independent risk factor in the development of PAD among CCS at Dr George Mukhari Academic Hospital (DGMAH). A sample of 120 CCS with PAD and a convenience sample of 100 CCS without PAD were recruited into the study. Blood COHb levels were measured using the ABL 90 FLEX CO-oximeter automated spectroscopy. Plasma nitric oxide (NO) levels were measure using ELISA. Logistic regression analysis was used to investigate the association of blood COHb and plasma NO with PAD. Blood COHb levels of CCS with PAD were significantly higher than those of CCS without PAD, and the NO levels of CCS with PAD were significantly lower than those of CCS without PAD. Although both the blood COHb and plasma NO in CCS were significantly associated with PAD in bivariate logistic analysis, only plasma NO was independently associated with PAD in multivariate logistic analysis. This finding is consistent with the hypothesis that COHb is a cause of arterial damage in PAD, leading to reduced NO, and therefore reduced arterial dilation.

Chronic cigarette smoke exposure triggers a vicious cycle of leukocyte and endothelial-mediated oxidant stress that results in vascular dysfunction

Although there is a strong association between cigarette smoking exposure (CSE) and vascular endothelial dysfunction (VED), the underlying mechanisms by which CSE triggers VED remain unclear. Therefore, studies were performed to define these mechanisms using a chronic mouse model of cigarette smoking (CS)-induced cardiovascular disease mirroring that in humans. C57BL/6 male mice were subjected to CSE for up to 48 wk. CSE impaired acetylcholine (ACh)-induced relaxation of aortic and mesenteric segments and triggered hypertension, with mean arterial blood pressure at 32 and 48 wk of exposure of 122 ± 6 and 135 ± 5 mmHg compared with 99 ± 4 and 102 ± 6 mmHg, respectively, in air-exposed mice. CSE led to monocyte activation with superoxide generation in blood exiting the pulmonary circulation. Macrophage infiltration with concomitant increase in NADPH oxidase subunits p22^phox and gp91^phox was seen in aortas of CS-exposed mice at 16 wk, with further increase out to 48 wk. Associated with this, increased superoxide production was detected that decreased with Nox inhibition. Tetrahydrobiopterin was progressively depleted in CS-exposed mice but not in air-exposed controls, resulting in endothelial nitric oxide synthase (eNOS) uncoupling and secondary superoxide generation. CSE led to a time-dependent decrease in eNOS and Akt expression and phosphorylation. Overall, CSE induces vascular monocyte infiltration with increased NADPH oxidase-mediated reactive oxygen species generation and depletes the eNOS cofactor tetrahydrobiopterin, uncoupling eNOS and triggering a vicious cycle of oxidative stress with VED and hypertension. Our study provides important insights toward understanding the process by which smoking contributes to the genesis of cardiovascular disease and identifies biomarkers predictive of disease.NEW & NOTEWORTHY In a chronic model of smoking-induced cardiovascular disease, we define underlying mechanisms of smoking-induced vascular endothelial dysfunction (VED). Smoking exposure triggered VED and hypertension and led to vascular macrophage infiltration with concomitant increase in superoxide and NADPH oxidase levels as early as 16 wk of exposure. This oxidative stress was accompanied by tetrahydrobiopterin depletion, resulting in endothelial nitric oxide synthase uncoupling with further superoxide generation triggering a vicious cycle of oxidative stress and VED.

Smoking-Induced Inhibition of Number and Activity of Endothelial Progenitor Cells and Nitric Oxide in Males Were Reversed by Estradiol in Premenopausal Females

Objectives

The number and activity of circulating EPCs were enhanced in premenopausal women contrast to postmenopausal females and age-matched males. Here, we investigated whether this favorable effect exists in premenopausal women and age-matched men with cigarette smoking.

Methods

In a cross-sectional study, the number and activity of circulating EPCs and nitric oxide production (NO) as well as flow-mediated vasodilation (FMD) in both premenopausal women and age-matched men with or without cigarette smoking were studied.

Results

Compared with age-matched men with or without smoking, the number and function of circulating EPCs as well as NO level in premenopausal women were obviously higher than that in the former and not affected by smoking. The number and function of circulating EPCs as well as NO level in male smokers were shown to be the most strongly inhibited. Furthermore, there was significant correlation between EPC number and activity, plasma NO level, and NO secretion by EPCs and FMD.

Conclusions

Estradiol was deemed to play an important role in enhancing the number and activity of EPCs and NO production in premenopausal women even when affected by smoking, which may be the important mechanisms underlying vascular protection of estradiol in premenopausal women, but not in age-matched men.

Evaluation of the effect of smokeless tobacco (Maras powder) on choroidal and retinal blood flow: an optical coherence tomography angiography study

ABSRTACT

PURPOSE: To investigate the acute and chronic effects of the use of smokeless tobacco (Maras powder) on macular and choroidal blood flow, via optical coherence tomography angiography (OCTA).

METHODS

The study included 30 eyes of 30 patients using smokeless tobacco (ST) as the study group and 30 eyes of 30 healthy individuals as the control group. All subjects underwent a full ophthalmological examination, and baseline OCTA measurements were taken. Flow area in superficial capillary plexus (SCP), in deep capillary plexus (DCP), in choriocapillaris (mm²⁾ and mean vascular density (VD) and foveal avascular zone in SCP and in DCP were assessed. Subfoveal choroidal thickness (SFCT) and central macular thickness were measured as well.

RESULTS

The SFCT measurements were determined to be significantly low in the study group (p < 0.001). In the comparison of the study group measurements at 5 m, 30 m and 1 h after using ST compared to the baseline measurements, SCP and DCP flow area, VD, CC flow area and SFCT were determined to have significantly decreased, statistically (p < 0.001).

CONCLUSION

OCTA could be important in showing that choroidal microvascular structures have been affected before occurence of the apparent clinical signs associated with acute and chronic ST use.

Evaluation of the acute effects of cigarette smoking on the eye of non-Smoking healthy young male subjects by optical coherence tomography angiography

Purpose: Investigation of the acute effects of cigarette smoking on the eye using optical coherence tomography angiography (OCTA) on young healthy non-smoking male subjects.Materials and methods: The right eye of 25 healthy non-smoking male subjects were included in this study. Selected parameters of the macular and circumpapillary vasculature were measured, including macular flow indices, foveal avascular zone, vessel densities of macula and optic disc using OCTA. The measurements of the subjects were performed on the first day without smoking at 0 min, 5 min, 30 min and 60 min. Measurements were repeated at the same regime on the second day after smoking. Paired samples t-test and repeated measures one-way analysis of variance test was used for the statistical analysis.Results: The repeated measures analysis of variance test using the Bonferroni adjustment demonstrated a significant change for superficial and deep foveal vessel density, flow area of choriocapillaris, and circumpapillary capillary density following smoking (range of p value was <0.001-0.004). Intraocular pressure, foveal avascular zone area, flow area of outer retina and foveal non-flow area of superficial layer measurements did not have any significant changes following smoking (range of p value was 0.192-0.812).Conclusion: In non-smoking cases, even smoking only one cigarette significantly decreased the vessel density parameters at the acute period. Even though there was an increase in measured parameters shortly after smoking, it had lessened when compared to non-smokers, even one hour following smoking.

Nicotine in Senescence and Atherosclerosis

Cigarette smoke is a known exacerbator of age-related pathologies, such as cardiovascular disease (CVD), atherosclerosis, and cellular aging (senescence). However, the role of nicotine and its major metabolite cotinine is yet to be elucidated. Considering the growing amount of nicotine-containing aerosol use in recent years, the role of nicotine is a relevant public health concern. A number of recent studies and health education sites have focused on nicotine aerosol-induced adverse lung function, and neglected cardiovascular (CV) impairments and diseases. A critical review of the present scientific literature leads to the hypothesis that nicotine mediates the effects of cigarette smoke in the CV system by increasing MAPK signaling, inflammation, and oxidative stress through NADPH oxidase 1 (Nox1), to induce vascular smooth muscle cell (VSMC) senescence. The accumulation of senescent VSMCs in the lesion cap is detrimental as it increases the pathogenesis of atherosclerosis by promoting an unstable plaque phenotype. Therefore, nicotine, and most likely its metabolite cotinine, adversely influence atherosclerosis.

Structural, functional, and molecular impact on the cardiovascular system in ApoE-/- mice exposed to aerosol from candidate modified risk tobacco products, Carbon Heated Tobacco Product 1.2 and Tobacco Heating System 2.2, compared with cigarette smoke

AIM

To investigate the molecular, structural, and functional impact of aerosols from candidate modified risk tobacco products (cMRTP), the Carbon Heated Tobacco Product (CHTP) 1.2 and Tobacco Heating System (THS) 2.2, compared with that of mainstream cigarette smoke (CS) on the cardiovascular system of ApoE-/- mice.

METHODS

Female ApoE-/- mice were exposed to aerosols from THS 2.2 and CHTP 1.2 or to CS from the 3R4F reference cigarette for up to 6 months at matching nicotine concentrations. A Cessation and a Switching group (3 months exposure to 3R4F CS followed by filtered air or CHTP 1.2 for 3 months) were included. Cardiovascular effects were investigated by echocardiographic, histopathological, immunohistochemical, and transcriptomics analyses.

RESULTS

Continuous exposure to cMRTP aerosols did not affect atherosclerosis progression, heart function, left ventricular (LV) structure, or the cardiovascular transcriptome. Exposure to 3R4F CS triggered atherosclerosis progression, reduced systolic ejection fraction and fractional shortening, caused heart LV hypertrophy, and initiated significant dysregulation in the transcriptomes of the heart ventricle and thoracic aorta. Importantly, the structural, functional, and molecular changes caused by 3R4F CS were improved in the smoking cessation and switching groups.

CONCLUSION

Exposure to cMRTP aerosols lacked most of the CS exposure-related functional, structural, and molecular effects. Smoking cessation or switching to CHTP 1.2 aerosol caused similar recovery from the 3R4F CS effects in the ApoE-/- model, with no further acceleration of plaque progression beyond the aging-related rate.

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.

Influence of Smoking Status on Risk of Incident Heart Failure: A Systematic Review and Meta-Analysis of Prospective Cohort Studies

Smoking is a well-known risk factor for atherosclerotic cardiovascular disease. However, there are insufficient data regarding the predictive influence of smoking status on the risk of incident heart failure (HF). This study involved a systematic review and meta-analysis of prospective cohort studies to identify the association of smoking status with incident risk of HF. Peer-reviewed articles published in PubMed, Embase, Web of Science, Cochrane, and CINAHL up to May 2019 were identified. Seven studies, based on 42,759 participants and 4826 HF cases, were included. Pooled hazard ratios (HRs) and their 95% confidence intervals (CI) were estimated using the fixed effects model. Subgroup analyses were conducted to define possible sources of heterogeneity. Current smokers aged 18 years and over had a greater risk of HF incidence compared with non-smokers (never or former smokers) (HR = 1.609, 95% CI, 1.470–1.761). Additionally, former smokers had a greater risk of HF incidence compared with never smokers (HR = 1.209, 95% CI, 1.084–1.348). The present study highlighted that never smokers have more obvious cardiovascular benefits than current or former smokers. Therefore, health professionals should support cessation at the earliest among current smokers and encourage young people and non-smokers not to start smoking.

C allele of -786 T>C polymorphism in the promoter region of endothelial nitric oxide synthase is responsible for endothelial dysfunction in the patients with rheumatoid arthritis

BACKGROUND

This study aimed to explore the roles of endothelial nitric oxide synthase (eNOS) in the control of metastasis of infection with endothelial dysfunction, as well as the roles of -786T>C polymorphism in eNOS promoter in the control of metastasis of endothelial function.

METHOD

In-silicon analysis and luciferase assay were used to identify the location of -786>C on the promoter of eNOS. Subsequently, real-time PCR and Western-blot were used to determine the expression level of eNOS. Ultrasound examination was used to detect baseline brachial artery diameter and flow-mediated dilation of patients in different treat groups.

RESULTS

-786T>C was located on the promoter of eNOS, and the luciferase activity of cells transfected with -786-C allele was much higher than empty vector, while even higher subsequent to transfection of -786-T allele. In addition, the result of ultrasound examination showed that the baseline brachial artery diameter was comparable between patients genotyped as TT, TC and CC, while the flow-mediated dilation of patients genotyped as TC was much higher compared with CC group, and the flow-mediated dilation of patients genotyped as TT even higher than TC group. We found eNOS messenger RNA and protein with TT genotype was significantly higher compared with other genotypes. And the production of NO was remarkably higher in TT groups compared with TC and CC, while the production of NO in TC and CC groups were similar.

CONCLUSION

These findings indicated that down-expression of -786T>C located on the promoter of eNOS is associated with an increased risk of endothelial dysfunction.

Relation Between Cigarette Smoking and Heart Failure (from the Multiethnic Study of Atherosclerosis)

We studied the association between cigarette smoking and incident heart failure (HF) in a racially diverse US cohort. We included 6,792 participants from the Multi-Ethnic Study of Atherosclerosis with information on cigarette smoking at baseline, characterized by status, intensity, burden, and time since quitting. Adjudicated outcomes included total incident HF cases and HF stratified by ejection fraction (EF) into HF with reduced EF (HFrEF; EF ≤ 40%) and preserved EF (HFpEF; EF ≥ 50%). We used Cox proportional hazards models adjusted for traditional cardiovascular risk factors and accounted for competing risk of each HF type. Mean age was 62 ± 10 years; 53% were women, 61% were nonwhite, and 13% were current smokers. A total of 279 incident HF cases occurred over a median follow-up of 12.2 years. The incidence rates of HFrEF and HFpEF were 2.2 and 1.9 cases per 1000 person-years, respectively. Current smoking was associated with higher risk of HF compared with never smoking (hazard ratio [HR], 2.05; 95% confidence interval [CI], 1.36 to 3.09); this was similar for HFrEF (HR, 2.58; 95% CI, 1.27 to 5.25) and HFpEF (HR, 2.51; 95% CI, 1.15 to 5.49). Former smoking was not significantly associated with HF (HR, 1.17; 95% CI, 0.88 to 1.56). Smoking intensity, burden, and time since quitting did not provide additional information for HF risk after accounting for smoking status.

Recognition and treatment of ischemic heart diseases in women

Heart disease is the leading cause of death among women in the industrialized world. However, women after myocardial infarctions (MIs) are less likely to receive preventive medications or revascularization and as many as 47% experience heart failure, stroke or die within 5 years. Premenopausal women with MIs frequently have coronary plaque erosions or dissections. Women under 50 years with angina and nonobstructive epicardial coronary artery disease often have coronary microvascular dysfunction (CMD) with reductions in coronary flow reserve that may require nontraditional therapies. In women with coronary artery disease treated with stents, the 3-year incidence of recurrent MI or death is 9.2%. Coronary bypass surgery operative mortality averages 4.6% for women compared with 2.4% in men. Addition of internal mammary artery and radial artery coronary grafts in women does not increase operative survival but improves 5-year outcome to greater than 80%.

Cardiovascular injury induced by tobacco products: assessment of risk factors and biomarkers of harm. A Tobacco Centers of Regulatory Science compilation

Although substantial evidence shows that smoking is positively and robustly associated with cardiovascular disease (CVD), the CVD risk associated with the use of new and emerging tobacco products, such as electronic cigarettes, hookah, and heat-not-burn products, remains unclear. This uncertainty stems from lack of knowledge on how the use of these products affects cardiovascular health. Cardiovascular injury associated with the use of new tobacco products could be evaluated by measuring changes in biomarkers of cardiovascular harm that are sensitive to the use of combustible cigarettes. Such cardiovascular injury could be indexed at several levels. Preclinical changes contributing to the pathogenesis of disease could be monitored by measuring changes in systemic inflammation and oxidative stress, organ-specific dysfunctions could be gauged by measuring endothelial function (flow-mediated dilation), platelet aggregation, and arterial stiffness, and organ-specific injury could be evaluated by measuring endothelial microparticles and platelet-leukocyte aggregates. Classical risk factors, such as blood pressure, circulating lipoproteins, and insulin resistance, provide robust estimates of risk, and subclinical disease progression could be followed by measuring coronary artery Ca2+ and carotid intima-media thickness. Given that several of these biomarkers are well-established predictors of major cardiovascular events, the association of these biomarkers with the use of new and emerging tobacco products could be indicative of both individual and population-level CVD risk associated with the use of these products. Differential effects of tobacco products (conventional vs. new and emerging products) on different indexes of cardiovascular injury could also provide insights into mechanisms by which they induce cardiovascular harm.

Review of biomarkers to assess the effects of switching from cigarettes to modified risk tobacco products

Context: One approach to reducing the harm caused by cigarette smoking, at both individual and population level, is to develop, assess and commercialize modified risk alternatives that adult smokers can switch to. Studies to demonstrate the exposure and risk reduction potential of such products generally involve the measuring of biomarkers, of both exposure and effect, sampled in various biological matrices.Objective: In this review, we detail the pros and cons for using several biomarkers as indicators of effects of changing from conventional cigarettes to modified risk products.Materials and methods: English language publications between 2008 and 2017 were retrieved from PubMed using the same search criteria for each of the 25 assessed biomarkers. Nine exclusion criteria were applied to exclude non-relevant publications.Results: A total of 8876 articles were retrieved (of which 7476 were excluded according to the exclusion criteria). The literature indicates that not all assessed biomarkers return to baseline levels following smoking cessation during the study periods but that nine had potential for use in medium to long-term studies.Discussion and conclusion: In clinical studies, it is important to choose biomarkers that show the biological effect of cessation within the duration of the study.

Evaluation of Macular Perfusion in Healthy Smokers by Using Optical Coherence Tomography Angiography

BACKGROUND AND OBJECTIVE

To investigate the macular perfusion changes in healthy smokers by using optical coherence tomography angiography (OCTA).

PATIENTS AND METHODS

OCTA measurements were taken for the right eyes of 40 smokers (Group 1) and age- and sex-matched control cases (Group 2). Group 1 underwent OCTA scanning with the XR Avanti AngioVue OCTA (Optovue, Fremont, CA) at baseline and at 5 minutes, 30 minutes, and 60 minutes after one standard cigarette smoking. The same scanning protocol was applied without smoking in Group 2. Macular vessel area density, flow index of the choriocapillaris, foveal avascular zone (FAZ), and central macular thickness were evaluated in both groups.

RESULTS

Group 1 consisted of 28 men and 12 women with a mean age of 41.2 years ± 9.1 years (range: 24 years to 63 years). The mean age of Group 2 was 42.6 years ± 8.4 years (range: 21 years to 65 years), which consisted of 28 men and 12 women. The mean baseline vessel area density, flow index of the choriocapillaris, FAZ, and central macular thickness showed no statistically significant differences between Groups 1 and 2. Although the flow index of choriocapillaris values were similar at the repetitive OCTA measurements in the control group (P > .05), it was decreased from 1.94 ± 0.06 to 1.89 ± 0.08, 1.90 ± 0.08, and 1.91 ± 0.07 at 5 minutes, 30 minutes, and 60 minutes following smoking, respectively, in Group 1 (P < .001).

CONCLUSION

Smoking causes a significant decrease in the blood flow index of the choriocapillary area by the acute effects of nicotine and other chemical substances in cigarettes on peripheral vascular structure, as evaluated by OCTA. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:617-622.].

Exercise Training Reverses Extrapulmonary Impairments in Smoke-exposed Mice

PURPOSE

Cigarette smoking is the main risk factor for chronic obstructive pulmonary disease and emphysema. However, evidence on the extrapulmonary effects of smoke exposure that precede lung impairments remains unclear at present, as are data on nonpharmacological treatments such as exercise training.

METHODS

Three groups of mice, including control (n = 10), smoking (n = 10), and smoking with 6 wk of high-intensity interval treadmill running (n = 11), were exposed to 20 wk of fresh air or whole-body cigarette smoke. Exercise capacity (peak oxygen uptake) and lung destruction (histology) were subsequently measured, whereas the heart, peripheral endothelium (aorta), and respiratory (diaphragm) and limb (extensor digitorum longus and soleus) skeletal muscles were assessed for in vivo and in vitro function, in situ mitochondrial respiration, and molecular alterations.

RESULTS

Smoking reduced body weight by 26% (P < 0.05) without overt airway destruction (P > 0.05). Smoking impaired exercise capacity by 15% while inducing right ventricular dysfunction by ~20%, endothelial dysfunction by ~20%, and diaphragm muscle weakness by ~15% (all P < 0.05), but these were either attenuated or reversed by exercise training (P < 0.05). Compared with controls, smoking mice had normal limb muscle and mitochondrial function (cardiac and skeletal muscle fibers); however, diaphragm measures of oxidative stress and protein degradation were increased by 111% and 65%, respectively (P < 0.05), but these were attenuated by exercise training (P < 0.05).

CONCLUSIONS

Prolonged cigarette smoking reduced exercise capacity concomitant with functional impairments to the heart, peripheral endothelium, and respiratory muscle that preceded the development of overt emphysema. However, high-intensity exercise training was able to reverse these smoke-induced extrapulmonary impairments.

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.

Smoking intensity and duration is associated with cardiac structure and function: the ECHOcardiographic Study of Hispanics/Latinos

Objective

Cardiovascular disease is the leading cause of death in smokers and this relationship is complicated by the multiplicity of cardiovascular effects of smoking. However, the relationship between intensity and duration of cigarette smoking and echocardiographic measures of right and left ventricular structure and function has been poorly studied.

Methods

We examined ECHO-SOL (Echocardiographic Study of Hispanics/Latinos) participants, a subset of the Hispanic Community Health Study/Study of Latinos. Participants were administered a detailed tobacco exposure questionnaire and a comprehensive echocardiography exam. Multivariable linear regression models (adjusted for age, sex, obesity, hypertension and diabetes statuses) were performed using sampling weights. Statistical significance was defined at p<0.01.

Results

There were 1818 ECHO-SOL participants (57.4% women, mean age 56.4 years). Among current smokers (n=304), increased duration of smoking, as measured by a younger age of smoking initiation, was significantly associated with higher mean left ventricular mass (LVM) and lower right ventricular (RV) function (lower right ventricular stroke volumes). More cigarettes smoked per day was significantly associated with higher mean LVM, worse diastolic function (higher E/e′ ratio), worse LV geometry (increased relative wall thickness) and worse RV function (decreasing right ventricular stroke volume). Among current smokers, higher mean lifetime pack-years (a combined measure of smoking intensity and duration) was associated with higher LVM, worse LV geometry, worse diastolic function, greater RV dilatation and worse RV function.

Conclusions

There is a dose–response relationship between intensity and duration of cigarette tobacco smoking with unfavourable changes of multiple measures of right-sided and left-sided cardiac structure and function.

Microcirculatory Bed, Microcirculation, and Smoking-Associated Endothelial Dysfunction in Young Adults

Computer-assisted video biomicroscopy of bulbar conjunctiva was employed to examine the sequelae of endothelial dysfunction manifested by microcirculatory bed abnormalities and microcirculation disturbances. The signs of endothelial dysfunction provoked by tobacco smoking in young adults disappeared after cessation of smoking, which resulted in pronounced widening of arterioles and capillaries as well as moderation of intravascular erythrocyte aggregation.

Validation of two point-of-care tests against standard lab measures of NO in saliva and in serum

Nitric oxide (NO) is an endogenous signaling molecule, which plays important roles in cardiometabolic health. A significant source of NO is dietary nitrate (NO3), which is initially metabolized by oral bacteria into nitrite (NO2-) and is subsequently converted into NO once digested in the acidic gastric environment. Inexpensive non-invasive tests for measuring nitrite from saliva have been developed as a means for individuals to monitor their NO bioavailability. However, few studies exist in the literature validating and comparing these products with standard lab assays. The objective of this study was to validate two commonly used commercial strips: Nitric Oxide Test Strips (Berkeley Test) and Nitric Oxide Indicator Strips (Neogenesis) against standard lab measures for saliva and serum nitrite/nitrate. A stratified random sample of 20 non-smoking, overweight or obese participants between 40 to 65 years of age, were selected for this study from the baseline data of the San Juan Overweight Adults Longitudinal Study (SOALS). There was a significant correlation between the measures from the two nitrite-detecting-strips after controlling for the stratification variables (metabolic syndrome, and mouthwash use) (r = 0.75). Measurements from both strips correlated significantly with salivary nitrite levels (r = 0.76 for Berkeley strips; r = 0.59 for Neogenesis). Neither of the strips had a significant correlation with the levels of saliva nitrate, serum nitrite and serum nitrate. In conclusion, commercially available Berkeley and Neogenesis strips provide a reasonable surrogate for salivary, but not for systemic nitrite levels.