Nicotine and sympathetic neurotransmission

Smoking cessation decreases arterial blood pressure in hypertensive smokers: A subgroup analysis of the randomized controlled trial GENTSMOKING

INTRODUCTION

High blood pressure in hypertensive smokers is affected by nicotine consumption. This study aimed to evaluate the effect of smoking cessation treatments on blood pressure in hypertensive smokers.

METHODS

A total of 113 hypertensive smokers on antihypertensives during smoking cessation treatment in the randomized controlled trial GENTSMOKING were considered for analysis. At Baseline (T0) and Week 12 (T12), systolic and diastolic blood pressure (SBP and DBP), and heart rate (HR) were measured using a semi-automated digital oscillometric device. Mean arterial pressure (MAP) and delta differences for SBP, DBP, HR, and MAP were calculated. Smoking cessation was confirmed by measuring carbon monoxide (CO) in exhaled air.

RESULTS

After 12 weeks of treatment, 72 participants ceased smoking (cessation group) and 41 did not (no cessation group). At T0, there was no statistically meaningful difference between groups with respect to age, body mass index, CO, and daily cigarette consumption. At T12, daily cigarette consumption and CO had decreased in both groups (p<0.001). The cessation group showed decreased SBP (131 ± 2 vs 125 ± 2 mmHg, p=0.004), DBP (79 ± 1 vs 77 ± 1 mmHg, p=0.031), MAP (96 ± 1 vs 93 ± 1 mmHg, p=0.005), and HR (79 ± 1 vs 74 ± 1 beats/min, p=0.001), and increased body weight (77.4 ± 2.1 vs 79.2 ± 2.2 kg, p<0.001). No significant differences were seen for these variables in the no cessation group. Decrease in blood pressure was significantly higher among hypertensive participants with SBP ≥130 mmHg: SBP (145 ± 2 vs 132 ± 2 mmHg, p<0.001), DBP (85 ± 2 vs 80 ± 1 mmHg, p=0.002), MAP (105 ± 1 vs 97 ± 1 mmHg, p<0.001), and HR (81 ± 2 vs 74 ± 2 beats/min, p=0.002). A positive correlation was found between HR and CO (r=0.34; p=0.001).

CONCLUSIONS

Smoking cessation treatment reduced blood pressure in hypertensive smokers, allowing them to reach therapeutic targets for hypertension management. Smoking cessation has a positive impact on hypertension treatment; therefore, it should be encouraged in clinical practice.

CLINICALTRIALSGOV IDENTIFIER

NCT03362099.

Nicotine Formulation Influences the Autonomic and Arrhythmogenic Effects of Electronic Cigarettes

INTRODUCTION

Evidence is mounting that electronic cigarette (e-cig) use induces cardiac sympathetic dominance and electrical dysfunction conducive to arrhythmias and dependent upon nicotine. A variety of nicotine types and concentrations are available in e-cigs, but their relative cardiovascular effects remain unclear. Here we examine how different nicotine forms (racemic, free base, and salt) and concentrations influence e-cig-evoked cardiac dysfunction and arrhythmogenesis and provide a mechanism for nicotine-salt-induced autonomic imbalance.

METHODS

ECG-telemetered C57BL/6J mice were exposed to filtered air (FA) or e-cig aerosols from propylene glycol and vegetable glycerin solvents either without nicotine (vehicle) or with increasing nicotine concentrations (1%, 2.5%, and 5%) for three 9-minute puff sessions per concentration. Spontaneous ventricular premature beat (VPB) incidence rates, heart rate, and heart rate variability (HRV) were compared between treatments. Subsequently, to test the role of β1-adrenergic activation in e-cig-induced cardiac effects, mice were pretreated with atenolol and exposed to either FA or 2.5% nicotine salt.

RESULTS

During puffing and washout phases, ≥2.5% racemic nicotine reduced heart rate and increased HRV relative to FA and vehicle controls, indicating parasympathetic dominance. Relative to both controls, 5% nicotine salt elevated heart rate and decreased HRV during washout, suggesting sympathetic dominance, and also increased VPB frequency. Atenolol abolished e-cig-induced elevations in heart rate and declines in HRV during washout, indicating e-cig-evoked sympathetic dominance is mediated by β1-adrenergic stimulation.

CONCLUSIONS

Our findings suggest that inhalation of e-cig aerosols from nicotine-salt-containing e-liquids could increase the cardiovascular risks of vaping by inducing sympathetic dominance and cardiac arrhythmias.

IMPLICATIONS

Exposure to e-cig aerosols containing commercially relevant concentrations of nicotine salts may increase nicotine delivery and impair cardiac function by eliciting β1-adrenoceptor-mediated sympathoexcitation and provoking ventricular arrhythmias. If confirmed in humans, our work suggests that regulatory targeting of nicotine salts through minimum pH standards or limits on acid additives in e-liquids may mitigate the public health risks of vaping.

Drug-induced AF: Arrhythmogenic Mechanisms and Management Strategies

AF is a prevalent condition that is associated with various modifiable and unmodifiable risk factors. Drug-induced AF, despite being commonly under-recognised, can be relatively easy to manage. Numerous cardiovascular and non-cardiovascular agents, including catecholaminergic agents, adenosine, anti-tumour agents and others, have been reported to induce AF. However, the mechanisms underlying drug-induced AF are diverse and not fully understood. The complexity of clinical scenarios and insufficient knowledge regarding drug-induced AF have rendered the management of this condition complicated, and current treatment guidelines follow those for other types of AF. Here, we present a review of the epidemiology of drug-induced AF and highlight a range of drugs that can induce or exacerbate AF, along with their molecular and electrophysiological mechanisms. Given the inadequate evidence and lack of attention, further research is crucial to underscore the clinical significance of drug-induced AF, clarify the underlying mechanisms and develop effective treatment strategies for the condition.

Acute nicotine intake increases feeding behavior through decreasing glucagon signaling in dependent male and female rats

Chronic use of nicotine is known to dysregulate metabolic signaling through altering circulating levels of feeding-related hormones, contributing to the onset of disorders like type 2 diabetes. However, little is known about the acute effects of nicotine on hormonal signaling. We previously identified an acute increase in food intake following acute nicotine, and we sought to determine whether this behavior was due to a change in hormone levels. We first identified that acute nicotine injection produces an increase in feeding behavior in dependent rats, but not nondependent rats. We confirmed that chronic nicotine use increases circulating levels of insulin, leptin, and ghrelin, and these correlate with rats' body weight and food intake. Acute nicotine injection in dependent animals decreased circulating GLP-1 and glucagon levels, and administration of glucagon prior to acute nicotine injection prevented the acute increase in feeding behavior. Thus, acute nicotine injection increases feeding behavior in dependent rats by decreasing glucagon signaling.

The Rising Use of E-Cigarettes: Unveiling the Health Risks and Controversies

The use of e-cigarettes has tremendously increased in recent times due to the widespread availability of e-cigarettes in diverse flavors, reduced cost compared to regular cigarettes, and misconception of being comparatively safe, which have led to around 2.55 million US middle and high school students smoking e-cigarettes. These devices use a nicotine-rich liquid, which is aerosolized electronically, producing vapors that may also include hazardous chemicals and heavy metals. E-cigarettes are associated with e-cigarette or vaping-associated lung injury, which presents as an acute respiratory ailment mirroring various pulmonary diseases. Additionally, it causes endothelial dysfunction, alters blood lipid profile by elevating circulating levels of low-density lipoprotein cholesterol, increases sympathetic tone, and is found to correlate with arterial stiffening, hence negatively affecting respiratory, cardiovascular, and overall health. We aim to provide a comprehensive analysis of the data on e-cigarettes and their harmful effects on health in comparison to conventional cigarette use by highlighting the pathophysiology of e-cigarette-induced adverse effects and critically analyzing the data both in favor and against its use. Our review concludes that no matter how much nicotine an e-cigarette contains, evidence shows that using it increases the risk of cardiovascular disease, albeit maybe not as much as smoking regular tobacco. Nonetheless, it is crucial to note that the long-term effects of e-cigarette usage are still not fully understood, and existing data have provided opposing viewpoints.

Associations of Dietary and Lifestyle Components with Atrial Fibrillation

Atrial fibrillation (AF) is a prevalent cardiac arrhythmia that still remains a significant health concern, especially due to its consequences, including stroke and heart failure. This review explores the intricate interplay between AF, lifestyle choices, and dietary habits. It is particularly focused on findings from diverse studies about non-pharmacological methods of managing AF. Moreover, its purpose is to elucidate the implementation of lifestyle changes such as physical activity or proper diet choices in the integrated treatment strategy of patients with AF.

Cardiovascular dysfunction induced by combined exposure to nicotine inhalation and high-fat diet

Smoking and high-fat diet (HFD) consumption are two modifiable risk factors for cardiovascular (CV) diseases, and individuals who are overweight or obese due to unhealthy diet are more likely to use tobacco products. In this study, we aim to investigate the combined effects of nicotine (the addictive component of all tobacco products) and HFD on CV health, which are poorly understood. C57BL/6N male mice were placed on either HFD (60 kcal% fat) or regular diet (22 kcal% fat) and exposed to air or nicotine vapor for 10-12 wk. CV function was monitored by echocardiography and radiotelemetry, with left ventricular (LV) catheterization and aortic ring vasoreactivity assays performed at end point. Mice on HFD exhibited increased heart rate and impaired parasympathetic tone, whereas nicotine exposure increased sympathetic vascular tone as evidenced by increased blood pressure (BP) response to ganglionic blockade. Although neither nicotine nor HFD alone or in combination significantly altered BP, nicotine exposure disrupted circadian BP regulation with reduced BP dipping. LV catheterization revealed that combined exposure to nicotine and HFD led to LV diastolic dysfunction with increased LV end-diastolic pressure (LVEDP). Moreover, combined exposure resulted in increased inhibitory phosphorylation of endothelial nitric oxide synthase and greater impairment of endothelium-dependent vasodilation. Finally, a small cohort of C57BL/6N females with combined exposure exhibited similar increases in LVEDP, indicating that both sexes are susceptible to the combined effect of nicotine and HFD. In summary, combined exposure to nicotine and HFD leads to greater CV harm, including both additive and new-onset CV dysfunction.NEW & NOTEWORTHY Nicotine product usage and high-fat diet consumption are two modifiable risk factors for cardiovascular diseases. Here, we demonstrate that in mice, combined exposure to inhaled nicotine and high-fat diet results in unique cardiovascular consequences compared with either treatment alone, including left ventricular diastolic dysfunction, dysregulation of blood pressure, autonomic dysfunction, and greater impairment of endothelium-dependent vasorelaxation. These findings indicate that individuals who consume both nicotine products and high-fat diet have distinctive cardiovascular risks.

Smoking-associated Electrocardiographic Abnormalities Predict Cardiovascular Mortality: Insights from NHANES

Background—

Smoking is associated with arrhythmia and sudden cardiac death, but the biological mechanisms remain unclear. Abnormal electrocardiogram (ECG) durations of ventricular repolarization (QT interval), atrial depolarization (P wave), and atrioventricular depolarization (PR interval and segment), predict cardiac arrhythmia and mortality.

Objectives—

To elucidate how smoking affects cardiac excitation, we assessed in a nationally representative sample (NHANES III) associations between cotinine, abnormalities in P duration, PR interval, PR segment, rate-corrected QT (QTc), QRS duration, and JT interval, and long-term mortality.

Methods—

We analyzed data from 5,633 adults using survey-weighted multinomial logistic regression to estimate associations between tobacco use (>15 ng/ml serum cotinine) and short (<5th percentile) or long (>95th percentile) ECG intervals, relative to reference (5 - 95th percentile).

Results—

After adjustment for demographics, risk factors, and conduction-altering medications, smoking was associated with a higher odds of short PR interval, PR segment, and QRS, and long JT. Broader ECG effects of smoking were also assessed by survey-weighted linear regression of continuous cotinine and ECG intervals, which revealed cotinine inversely associated with PR segment and QTc. Over a 22-year follow-up, many ECG abnormalities predicted cardiovascular mortality in smokers, including long JT, QRS, and QTc, and short QRS.

Conclusions—

Smoking increases likelihood for rapid atrioventricular conduction, rapid ventricular depolarization, and slow ventricular repolarization. The ventricular electrophysiologic abnormalities associated with smoking also predict cardiovascular mortality in smokers; however, traditional ECG measures of cardiac risk like QTc can overlook these ventricular defects and their independent predictive value in smokers.

Synthetic Peptide Fragments of the Wtx Toxin Reduce Blood Pressure in Rats under General Anesthesia

Previously, it was shown that the non-conventional toxin WTX from the venom of the cobra Naja kaouthia, when administered intravenously, caused a decrease in blood pressure (BP) and an increase in heart rate (HR) in rats [13]. To identify the site of the toxin molecule responsible for these effects, we studied the influence of synthetic peptide fragments of the WTX on BP and HR in normotensive male Sprague-Dawley rats under general anesthesia induced by Telazol and Xylazine. It was found that peptides corresponding to the WTX central polypeptide loop, stabilized by a disulfide bond, at intravenous injection at concentrations from 0.1 to 1.0 mg/mL caused a dose-dependent decrease in BP, with the HR increasing only in the first 5-10 min after administration. Thus, WTX fragments corresponding to the central polypeptide loop reproduce the decrease in blood pressure caused by the toxin.

Association between cardiovascular risk factors and atrial fibrillation

Background

The most prevalent sustained arrhythmia in medical practice, atrial fibrillation (AF) is closely associated with a high risk of cardiovascular disease. Nevertheless, the risk of AF associated with cardiovascular risk factors has not been well elucidated. We pooled all published studies to provide a better depiction of the relationship among cardiovascular risk factors with AF.

Methods

Studies were searched in the MEDLINE, Web of Science, and EMBASE databases since initiation until January 15, 2022. Prospective cohort studies assessing the relationship a minimum of single cardiovascular risk factors to AF incidence were included if they contained adequate data for obtaining relative risks (RR) and 95% confidence intervals (CI). Random-effects models were utilized to perform independent meta-analyses on each cardiovascular risk factor. PROSPERO registry number: CRD42022310882.

Results

A total of 17,098,955 individuals and 738,843 incident cases were reported for data from 101 studies included in the analysis. In all, the risk of AF was 1.39 (95% CI, 1.30-1.49) for obesity, 1.27 (95% CI, 1.22-1.32) per 5 kg/m2 for increase in body mass index, 1.19 (95% CI, 1.10-1.28) for former smokers, 1.23 (95% CI, 1.09-1.38) for current smokers, 1.31 (95% CI, 1.23-1.39) for diabetes mellitus, 1.68 (95% CI, 1.51-1.87) for hypertension, and 1.12 (95% CI, 0.95-1.32) for dyslipidemia.

Interpretation

Adverse cardiovascular risk factors correlate with an increased risk of AF, yet dyslipidemia does not increase the risk of AF in the general population, potentially providing new insights for AF screening strategies among patients with these risk factors.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, PROSPERO identifier (CRD42022310882).

Electronic Cigarette Vaping with Nicotine Causes Increased Thrombogenicity and Impaired Microvascular Function in Healthy Volunteers: A Randomised Clinical Trial

Electronic cigarette (EC) vaping is increasingly popular, despite growing evidence of adverse health effects. To further evaluate the impact of EC use on vascular health, we investigated the effects of brief EC inhalation on flow-dependent thrombus formation and microcirculation in healthy volunteers. The study was performed with a randomised double-blind crossover design. Twenty-two healthy subjects aged between 18 and 45 years with occasional tobacco use were recruited. Subjects inhaled 30 puffs of EC aerosol with and without nicotine on two occasions separated by a wash-out period of at least 1 week. Blood samples were collected at baseline and at 15 and 60 min following exposure and analysed with the Total-Thrombus-formation analysis system evaluating fibrin-rich thrombus formation and platelet thrombus formation in whole blood under flow. Microvascular function was assessed at baseline and 30 min after exposure by laser speckle contrast imaging and iontophoresis of acetylcholine and sodium nitroprusside (SNP) to evaluate the endothelium-dependent and independent pathways of vasodilation. Compared with nicotine free EC aerosol, exposure to EC aerosol with nicotine significantly increased platelet thrombus formation and fibrin-rich thrombus formation at 15 min (p = 0.017 and p = 0.037, respectively) with normalisation after 60 min. Peak SNP-mediated microvascular perfusion, i.e. endothelium-independent vasodilation, was reduced following EC vaping with nicotine compared with baseline (p = 0.006). Thirty puffs of EC aerosol with nicotine increased platelet and fibrin-dependent thrombus formation and reduced microvascular dilatation capacity. No compelling effects of EC vaping without nicotine were observed, indicating nicotine as the main effector. Trial registration: ClinicalTrials.gov Identifier: NCT04175457 URL: https://clinicaltrials.gov/ct2/show/NCT04175457.

Current Evidence on Prevention of Atrial Fibrillation: Modifiable Risk Factors and the Effects of Risk Factor Intervention

Atrial fibrillation (AF) is one of the most encountered arrhythmias in clinical practice. It is also estimated that the absolute AF burden may increase by greater than 60% by 2050. It is inevitable that AF will become one of the largest epidemics in the world and may pose a major health problem for countries. Although AF rarely causes mortality in the acute period, it causes a significant increase in mortality and morbidity, including a fivefold increase in the risk of stroke, a twofold increase in dementia, and a twofold increase in myocardial infarction in the chronic period. Despite all the advances in the treatment of AF, it is better understood day by day that preventing AF may play a key role in reducing AF and its related complications. Modification of the main modifiable factors such as quitting smoking, abstaining from alcohol, changing eating habits, and exercise seems to be the first step in preventing AF. The strict adherence to the treatment process of secondary causes predisposing to AF such as DM, hypertension, obesity, and sleep apnea is another step in the prevention of AF. Both an individual approach and global public health campaigns can be highly beneficial to reduce the risk of AF. In this review, we aimed to summarize the current evidence on the relationship between modifiable risk factors and AF, and the impact of possible interventions on these factors in preventing or reducing the AF burden in the light of recently published guidelines and studies.

A prediction model for new-onset atrial fibrillation following coronary artery bypass graft surgery: A multicenter retrospective study

Objective

Developing and assessing a risk prediction model of postoperative atrial fibrillation (POAF) after coronary artery bypass grafting (CABG), and aims to provide a reference for the prediction and prevention.

Design

A retrospective case-control study.

Setting

Three major urban teaching and university hospitals and tertiary referral centers.

Participants

consecutive patients undergoing CABG.

Interventions

The study was retrospective and no interventions were administered to patients.

Measurements and main results

In the study, the overall new-onset POAF prevalence was approximately 28%. A prediction model for POAF with nine significant indicators was developed, and identified new predictors of POAF: left ventricular end diastolic diameter (LVEDD), intraoperative defibrillation, and intraoperative temporary pacing lead implantation. The model had good discrimination in both the derivation and validation cohorts, with the area under the receiver operating characteristic curves (AUCs) of 0.621 (95% CI = 0.602-0.640) and 0.616 (95% CI = 0.579-0.651), respectively, and showed good calibration. Compared with CHA₂DS₂-VASc, HATCH score, and the prediction model of POAF after CABG developed based on a small sample of clinical data from a single center in China, the model in this study had better discrimination.

Conclusion

We have developed and validated a new prediction model of POAF after CABG using multicenter data that can be used in the clinic for early identification of high-risk patients of POAF, and to help effectively prevent POAF in postoperative patients.

Nicotine Use and Metabotropic Glutamate Receptor 5 in Individuals With Major Depressive and Posttraumatic Stress Disorders

Metabotropic glutamate receptor 5 (mGluR5) dysregulation has been implicated in the pathophysiology of many psychiatric disorders, as well as nicotine use and dependence. We used positron emission tomography with [18F]FPEB to measure mGluR5 availability in vivo in 6 groups: (1) nicotine users (NUs) without other psychiatric comorbidities (n = 23); (2) comparison controls (CCs) without nicotine use or psychiatric comorbidities (n = 38); (3) major depressive disorder subjects with concurrent nicotine use (MDD-NU; n = 19); (4) MDD subjects without concurrent nicotine use (MDD-CC; n = 20); (5) posttraumatic stress disorder subjects with concurrent nicotine use (PTSD-NU; n = 17); and (6) PTSD subjects without concurrent nicotine use (PTSD-CC; n = 16). The goal of the study was to test the hypothesis that mGluR5 availability in key corticolimbic regions of interest (ROIs) is different in NU with versus without comorbid psychiatric disorders (ROI: dorsolateral prefrontal cortex [dlPFC], orbitofrontal cortex [OFC], ventromedial prefrontal cortex [vmPFC], anterior cingulate cortex [ACC], amygdala, hippocampus). We found that NU had 11%-13% lower mGluR5 availability in OFC, vmPFC, dlPFC, and ACC as compared with CC, while PTSD-NU had 9%-11% higher mGluR5 availability in OFC, dlPFC, and ACC compared with PTSD. Furthermore, relationships between mGluR5 availability and psychiatric symptoms varied as a function of psychiatric diagnosis among NUs. NU showed a negative correlation between mGluR5 and smoking cravings and urges (r's = -0.58 to -0.70, p's = 0.011 - 0.047), while PTSD-NU had the reverse relationship (r's = 0.60-0.71, p's = 0.013-0.035 in ACC, vmPFC, and dlPFC). These findings have substantial implications for our understanding of glutamate homeostasis in psychiatric subgroups and for identifying key neural phenotypes among NU. mGluR5 is a potential treatment target for precision medicine in individuals with nicotine use.

Correlation between Adrenoceptor Expression and Clinical Parameters in Degenerated Lumbar Intervertebral Discs

Despite advanced knowledge of the cellular and biomechanical processes of intervertebral disc degeneration (IVDD), the trigger and underlying mechanisms remain unclear. Since the sympathetic nervous system (SNS) has been shown to exhibit catabolic effects in osteoarthritis pathogenesis, it is attractive to speculate that it also influences IVDD. Therefore, we explored the adrenoceptor (AR) expression profile in human IVDs and correlated it with clinical parameters of patients. IVD samples were collected from n = 43 patients undergoing lumbar spinal fusion surgery. AR gene expression was analyzed by semi-quantitative polymerase chain reaction. Clinical parameters as well as radiological Pfirrmann and Modic classification were collected and correlated with AR expression levels. In total human IVD homogenates α1A-, α1B-, α2A-, α2B-, α2C-, β1- and β2-AR genes were expressed. Expression of α1A- (r = 0.439), α2A- (r = 0.346) and β2-AR (r = 0.409) showed a positive and significant correlation with Pfirrmann grade. α1A-AR expression was significantly decreased in IVD tissue of patients with adjacent segment disease (p = 0.041). The results of this study indicate that a relationship between IVDD and AR expression exists. Thus, the SNS and its neurotransmitters might play a role in IVDD pathogenesis. The knowledge of differential AR expression in different etiologies could contribute to the development of new therapeutic approaches for IVDD.

Roles of alpha-7 nicotinic acetylcholine receptors and spleen in the lung injury induced by a repeated saline lavage in rat

BACKGROUND

The study aimed to determine whether or notα7 nicotinic acetylcholine receptors (α7nAChR) induce anti-inflammatory effects directly in the lung or through the spleen pathway in a sterile model of lung injury by saline lavage.

METHODS

Male Sprague Dawley rats were divided into seven groups; Sham, splenectomy (SPX), saline lavage (LAV), LAV treated with α7nAChR agonist nicotine (LAV + NIC), and LAV treated with NIC and a selective α7nAChR antagonist MLA (LAV+MLA+NIC), LAV and splenectomy (LAV+SPX), and LAV+SPX treated with nicotine (LAV+SPX+NIC). Tracheostomy and catheterization of the femoral artery were performed under deep anesthesia. Animals were subjected to volume-controlled ventilation and lung injury by 10 repeated saline lavages. Splenectomy was achieved one week before the induction of lung injury. The recovery phase lasted for 3 h, and drugs were injected 1 h after the last lavage.

RESULTS

Mean arterial blood pressure (MBP), heart rate (HR), PaO₂, PaO₂/FiO₂ ratio, and pH decreased, whereas, maximal inspiratory (MIP) and expiratory (MEP) pressures, and PaCO₂ increased 1 h after the saline lavage. Nicotine corrected entirely all the above parameters in the LAV + NIC group. MLA or SPX prevented the effects of nicotine on the above parameters, except that MLA had no extra effect on MIP or MEP. In addition, nicotine improved lung compliance in the LAV + NIC and LAV + SPX + NIC groups, though it was inhibited by MLA in the LAV + MLA + NIC group. The increases of plasma and lung tissue malondialdehyde (MDA) in the LAV group were diminished by nicotine, whereas, MLA and SPX prevented these reductions. Besides, nicotine could reduce plasma MDA in the LAV + SPX + NIC group. Total BAL cell count, protein BAL/protein plasma ratio, and lung histological scores were attenuated by nicotine in the LAV + NIC group, whereas, MLA reversed the mentioned alterations in the LAV + MLA + NIC group. However, splenectomy could not stop the decreasing effect of nicotine on the total BAL cell in the LAV + SPX + NIC group.

CONCLUSIONS

In this study, we indicated that α7nAChR and spleen play roles in cholinergic anti-inflammatory pathways in saline lavage-induced lung injury. However, our results are in favor of at least some direct effects of α 7nAChR in the lung.

Important Drug-Drug Interactions for the Addiction Psychiatrist

The misuse of illicit substances, prescribed medications, and alcohol poses obvious health risks to afflicted individuals. When addressing these health risks, the overarching concerns generally relate to the direct effects that various substances can have on the functioning of multiple organ systems: cardiac, pulmonary, central nervous system, and others. What is not always evident, but potentially equally or even more dire, are the risks arising from drug-drug interactions involving illicit drugs and alcohol, whether with each other, or with prescribed medications. This review provides some basics that enable the reader to fruitfully approach the broad topic of drug-drug interactions.

Pharmacological and physiological response in Apoe-/- mice exposed to cigarette smoke or e-cigarette aerosols

OBJECTIVE

Electronic cigarettes (e-cigs) are popular nicotine delivery devices, yet the health effects remain unclear. To determine equivalent biomarkers, we characterized the immediate response in Apoe^-/- mice exposed to tank/box-mod e-cig (e-cig_tank), pod e-cig (e-cig_pod), or cig smoke.

MATERIALS AND METHODS

Reproducible puff profiles were generated for each aerosol and delivered to Apoe^-/- mice via a nose-only exposure system. Serum cotinine levels were quantified at various time points through ELISA and utilized to model cotinine pharmacokinetics. In addition, particle size measurements and mouse respiratory function were characterized to calculate particle dosimetry.

RESULTS AND DISCUSSION

Cig and e-cig_tank particles were lognormally distributed with similar count median diameters (cig: 178 ± 2, e-cig_tank: 200 ± 34nm), while e-cig_pod particles were bimodally distributed and smaller (116 ± 13 and 13.3 ± 0.4 nm). Minute volumes decreased with cig exposure (5.4 ± 2.7 mL/min) compared to baseline (90.8 ± 11.6 mL/min), and less so with e-cig_tank (45.2 ± 9.2 mL/min) and e-cig_pod exposures (58.6 ± 6.8 mL/min), due to periods of apnea in the cig exposed groups. Cotinine was absorbed and eliminated most rapidly in the e-cig_pod group (tmax = 14.5; t1/2' = 51.9 min), whereas cotinine was absorbed (cig: 50.4, e-cig_tank: 40.1 min) and eliminated (cig: 104.6, e-cig_tank: 94.1 min) similarly in the cig and e-cig_tank groups. For exposure times which equate the area under the cotinine-concentration curve, ∼6.4× (e-cig_tank) and 4.6× (e-cig_pod) more nicotine deposited in e-cig compared to cig exposed mice.

CONCLUSIONS

This study provides a basis for incorporating cotinine pharmacokinetics into preclinical exposure studies, allowing for longitudinal studies of structural and functional changes due to exposure.

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.

Alpha7 nicotinic acetylcholine receptor mediates chronic nicotine inhalation-induced cardiopulmonary dysfunction

Cigarette smoking remains the leading modifiable risk factor for cardiopulmonary diseases; however, the effects of nicotine alone on cardiopulmonary function remain largely unknown. Previously, we have shown that chronic nicotine vapor inhalation in mice leads to the development of pulmonary hypertension (PH) with right ventricular (RV) remodeling. The present study aims to further examine the cardiopulmonary effects of nicotine and the role of the α7 nicotinic acetylcholine receptor (α7-nAChR), which is widely expressed in the cardiovascular system. Wild-type (WT) and α7-nAChR knockout (α7-nAChR-/-) mice were exposed to room air (control) or nicotine vapor daily for 12 weeks. Consistent with our previous study, echocardiography and RV catheterization reveal that male WT mice developed increased RV systolic pressure with RV hypertrophy and dilatation following 12-week nicotine vapor exposure; in contrast, these changes were not observed in male α7-nAChR-/- mice. In addition, chronic nicotine inhalation failed to induce PH and RV remodeling in female mice regardless of genotype. The effects of nicotine on the vasculature were further examined in male mice. Our results show that chronic nicotine inhalation led to impaired acetylcholine-mediated vasodilatory response in both thoracic aortas and pulmonary arteries, and these effects were accompanied by altered endothelial nitric oxide synthase phosphorylation (enhanced inhibitory phosphorylation at threonine 495) and reduced plasma nitrite levels in WT but not α7-nAChR-/- mice. Finally, RNA sequencing revealed up-regulation of multiple inflammatory pathways in thoracic aortas from WT but not α7-nAChR-/- mice. We conclude that the α7-nAChR mediates chronic nicotine inhalation-induced PH, RV remodeling and vascular dysfunction.

Electronic Cigarette Use and the Risk of Cardiovascular Diseases

Electronic cigarettes or e-cigarettes are the most frequently used tobacco product among adolescents. Despite the widespread use of e-cigarettes and the known detrimental cardiac consequences of nicotine, the effects of e-cigarettes on the cardiovascular system are not well-known. Several in vitro and in vivo studies delineating the mechanisms of the impact of e-cigarettes on the cardiovascular system have been published. These include mechanisms associated with nicotine or other components of the aerosol or thermal degradation products of e-cigarettes. The increased hyperlipidemia, sympathetic dominance, endothelial dysfunction, DNA damage, and macrophage activation are prominent effects of e-cigarettes. Additionally, oxidative stress and inflammation are unifying mechanisms at many levels of the cardiovascular impairment induced by e-cigarette exposure. This review outlines the contribution of e-cigarettes in the development of cardiovascular diseases and their molecular underpinnings.

Autonomic Regulation of Nociceptive and Immunologic Changes in a Mouse Model of Complex Regional Pain Syndrome

Chronic pain frequently develops after limb injuries, and its pathogenesis is poorly understood. We explored the hypothesis that the autonomic nervous system regulates adaptive immune system activation and nociceptive sensitization in a mouse model of chronic post-traumatic pain with features of complex regional pain syndrome (CRPS). In studies sympathetic signaling was reduced using 6-hydroxydopamine (6-OHDA) or lofexidine, while parasympathetic signaling was augmented by nicotine administration. Hindpaw allodynia, unweighting, skin temperature, and edema were measured at 3 and 7 weeks after fracture. Hypertrophy of regional lymph nodes and IgM deposition in the skin of injured limbs were followed as indices of adaptive immune system activation. Passive transfer of serum from fracture mice to recipient B cell deficient (muMT) mice was used to assess the formation of pain-related autoantibodies. We observed that 6-OHDA or lofexidine reduced fracture-induced hindpaw nociceptive sensitization and unweighting. Nicotine had similar effects. These treatments also prevented IgM deposition, hypertrophy of popliteal lymph nodes, and the development of pronociceptive serum transfer effects. We conclude that inhibiting sympathetic or augmenting parasympathetic signaling inhibits pro-nociceptive immunological changes accompanying limb fracture. These translational results support the use of similar approaches in trials potentially alleviating persistent post-traumatic pain and, possibly, CRPS. PERSPECTIVE: Selective treatments aimed at autonomic nervous system modulation reduce fracture-related nociceptive and functional sequelae. The same treatment strategies limit pain-supporting immune system activation and the production of pro-nociceptive antibodies. Thus, the therapeutic regulation of autonomic activity after limb injury may reduce the incidence of chronic pain.

Immediate physiological effects of acute electronic cigarette use in humans: A systematic review and meta-analysis

BACKGROUND

Electronic cigarettes (e-cigs) are widely used devices that were initially created to aid in smoking cessation. However, their acute physiological effects are unclear and there have been a number of E-cig and Vaping Acute Lung Injury (EVALI) events reported.

RESEARCH QUESTION

What are the immediate physiological effects (i.e. cardiovascular, respiratory or blood-based responses) of acute e-cig usage in humans?

STUDY DESIGN AND METHODS

PubMed, Web of Science, Cochrane and Scopus databases were searched for English or French peer-reviewed articles published until May 20, 2021 and measuring at least one physiological parameter before and after using an e-cig. The study followed PRISMA guidelines and assessed article quality using the Downs and Black checklist. Independent extraction was conducted by two reviewers. Data were pooled using random-effect models. Sensitivity analysis and meta-regressions were performed to explore heterogeneity.

MAIN OUTCOMES

Systolic and diastolic blood pressure, heart rate, augmentation index (AIx75), fraction of exhaled nitric oxide (FeNO), and spirometry were the most frequently assessed parameters and were therefore chosen for meta-analyses.

RESULTS

Of 19823 articles screened, 45 articles were included for the qualitative synthesis, and 27 articles (919 patients) were included in meta-analyses. Acute use of nicotine e-cig was associated with increased heart rate(SMD = 0.71; 95%CI 0.46-0.95), systolic blood pressure (SMD = 0.38; 95%CI 0.18-0.57), diastolic blood pressure (SMD = 0.52; 95%CI 0.33-0.70), and augmentation index AIx75 (SMD = 0.580; 95%CI 0.220-0.941), along with decreased FeNO (SMD = -0.26; 95%CI -0.49 to -0.04). E-cig exposure wasn't associated with significant changes in any spirometry measure.

INTERPRETATION

Acute use of nicotine e-cigs was associated with statistically significant cardiovascular and respiratory responses. These devices have a physiological impact that could be clinically relevant, especially in terms of cardiovascular morbidity. However, the direct consequences of long-term e-cig use needs to be further explored.

Comprehensive Parent-Metabolite PBPK/PD Modeling Insights into Nicotine Replacement Therapy Strategies

Background

Nicotine, the pharmacologically active substance in both tobacco and many electronic cigarette (e-cigarette) liquids, is responsible for the addiction that sustains cigarette smoking. With 8 million deaths worldwide annually, smoking remains one of the major causes of disability and premature death. However, nicotine also plays an important role in smoking cessation strategies.

Objectives

The aim of this study was to develop a comprehensive, whole-body, physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) model of nicotine and its major metabolite cotinine, covering various routes of nicotine administration, and to simulate nicotine brain tissue concentrations after the use of combustible cigarettes, e-cigarettes, nicotine gums, and nicotine patches.

Methods

A parent–metabolite, PBPK/PD model of nicotine for a non-smoking and a smoking population was developed using 91 plasma and brain tissue concentration–time profiles and 11 heart rate profiles. Among others, cytochrome P450 (CYP) 2A6 and 2B6 enzymes were implemented, including kinetics for CYP2A6 poor metabolizers.

Results

The model is able to precisely describe and predict both nicotine plasma and brain tissue concentrations, cotinine plasma concentrations, and heart rate profiles. 100% of the predicted area under the concentration–time curve (AUC) and maximum concentration (C_max) values meet the twofold acceptance criterion with overall geometric mean fold errors of 1.12 and 1.15, respectively. The administration of combustible cigarettes, e-cigarettes, nicotine patches, and nicotine gums was successfully implemented in the model and used to identify differences in steady-state nicotine brain tissue concentration patterns.

Conclusions

Our PBPK/PD model may be helpful in further investigations of nicotine dependence and smoking cessation strategies. As the model represents the first nicotine PBPK/PD model predicting nicotine concentration and heart rate profiles after the use of e-cigarettes, it could also contribute to a better understanding of the recent increase in youth e-cigarette use.

Electronic supplementary material

The online version of this article (10.1007/s40262-020-00880-4) contains supplementary material, which is available to authorized users.

Cytotoxicity and Genotoxicity of E-Cigarette Generated Aerosols Containing Diverse Flavoring Products and Nicotine in Oral Epithelial Cell Lines

Electronic cigarettes are the most commonly used nicotine containing product among teenagers. The oral epithelium is the first site of exposure and our recent work revealed considerable diversity among e-liquids for composition and level of chemical constituents that impact nicotine deposition in a human oral-trachea cast and affect the formation of reactive carbonyls. Here, we evaluate the dose response for cytotoxicity and genotoxicity of e-cigarette-generated aerosols from 10 diverse flavored e-liquid products with and without nicotine compared with unflavored in 3 immortalized oral epithelial cell lines. Three e-liquids, Blue Pucker, Love Potion, and Jamestown caused ≥20% cell toxicity assessed by the neutral red uptake assay. Nine products induced significant levels of oxidative stress up to 2.4-fold quantified by the ROS-Glo assay in at least 1 cell line, with dose response seen for Love Potion with and without nicotine across all cell lines. Lipid peroxidation detected by the thiobarbituric acid reactive substances assay was less common among products; however, dose response increases up to 12-fold were seen for individual cell lines. Micronuclei formation indicative of genotoxicity was increased up to 5-fold for some products. Blue Pucker was the most genotoxic e-liquid, inducing micronuclei across all cell lines irrespective of nicotine status. A potency score derived from all assays identified Blue Pucker and Love Potion as the most hazardous e-liquids. These in vitro acute exposure studies provide new insight about the potential for some flavored vaping products to induce significant levels of oxidative stress and genotoxicity.

Modulation of preeclampsia by the cholinergic anti-inflammatory pathway: Therapeutic perspectives

The cholinergic anti-inflammatory pathway (CAP) is vital for the orchestration of the immune and inflammatory responses under normal and challenged conditions. Over the past two decades, peripheral and central circuits of CAP have been shown to be critically involved in dampening the inflammatory reaction in a wide array of inflammatory disorders. Additionally, emerging evidence supports a key role for CAP in the regulation of the female reproductive system during gestation as well as in the advent of serious pregnancy-related inflammatory insults such as preeclampsia (PE). Within this framework, the modulatory action of CAP encompasses the perinatal maternal and fetal adverse consequences that surface due to antenatal PE programming. Albeit, a considerable gap still exists in our knowledge of the precise cellular and molecular underpinnings of PE/CAP interaction, which hampered global efforts in safeguarding effective preventive or therapeutic measures against PE complications. Here, we summarize reports in the literature regarding the roles of peripheral and reflex cholinergic neuroinflammatory pathways of nicotinic acetylcholine receptors (nAChRs) in reprogramming PE complications in mothers and their progenies. The possible contributions of α7-nAChRs, cholinesterases, immune cells, adhesion molecules, angiogenesis, and endothelial dysfunction to the interaction have also been reviewed.

Cytisine and cytisine derivatives. More than smoking cessation aids

Cytisine, a natural bioactive compound that is mainly isolated from plants of the Leguminosae family (especially the seeds of Laburnum anagyroides), has been marketed in central and eastern Europe as an aid in the clinical management of smoking cessation for more than 50 years. Its main targets are neuronal nicotinic acetylcholine receptors (nAChRs), and pre-clinical studies have shown that its interactions with various nAChR subtypes located in different areas of the central and peripheral nervous systems are neuroprotective, have a wide range of biological effects on nicotine and alcohol addiction, regulate mood, food intake and motor activity, and influence the autonomic and cardiovascular systems. Its relatively rigid conformation makes it an attractive template for research of new derivatives. Recent studies of structurally modified cytisine have led to the development of new compounds and for some of them the biological activities are mediated by still unidentified targets other than nAChRs, whose mechanisms of action are still being investigated. The aim of this review is to describe and discuss: 1) the most recent pre-clinical results obtained with cytisine in the fields of neurological and non-neurological diseases; 2) the effects and possible mechanisms of action of the most recent cytisine derivatives; and 3) the main areas warranting further research.

Tobacco Use and Periodontal Disease-The Role of Microvascular Dysfunction

Periodontal disease consists in highly prevalent wide-ranging inflammatory conditions that affect the supporting apparatus of teeth. Tobacco use is the most important risk factor for periodontal disease as it increases disease severity and periodontal surgery complications. Tobacco use is harmful for the vasculature by causing microvascular dysfunction, which is known to negatively affect periodontal disease. To the author's knowledge this paper is the first comprehensive review on the mechanisms by which tobacco use affects oral microcirculation and impacts the pathophysiology of periodontal disease. In healthy subjects, acute nicotine administration or tobacco use (smoking/smokeless forms) increases the blood flow in the oral mucosa due to local irritation and increased blood pressure, which overcome neural- and endocrine-mediated vasoconstriction. Chronic tobacco smokers display an increased gingival microvascular density, which is attributed to an increased capillary recruitment, however, these microcirculatory units show higher tortuosity and lower caliber. These morphological changes, together with the repetitive vasoconstrictive insults, contribute to lower gingival perfusion in chronic smokers and do not completely regress upon smoking cessation. In periodontal disease there is considerable gingival inflammation and angiogenesis in non-smokers which, in chronic smokers, are considerably suppressed, in part due to local immune suppression and oxidative stress. Tobacco exposure, irrespective of the form of use, causes long-term microvascular dysfunction that increases the risk of complications due to the natural disease course or secondary therapeutic strategies.

Swedish snuff (snus) and risk of cardiovascular disease and mortality: prospective cohort study of middle-aged and older individuals

BACKGROUND

Cigarette smoking is a well-known risk factor for cardiovascular disease (CVD), but whether smokeless tobacco such as snuff is associated with the risk of CVD is still unclear. We investigated the association of the use of Swedish oral moist snuff (snus) with a broad range of CVDs and CVD mortality.

METHODS

We used data from a population-based cohort of 41,162 Swedish adults with a mean baseline age of 70 (56-94) years who completed questionnaires regarding snus use and other lifestyle habits and health characteristics. Participants were followed up for incident cardiovascular outcomes and death over 8 years through linkage to the Swedish National Patient and Death Registers. Hazard ratios (HR) were estimated by Cox proportional hazards regression. We conducted analyses among all subjects as well as among never smokers to reduce residual confounding from smoking.

RESULTS

After adjustment for smoking and other confounders, snus use was not associated with myocardial infarction, heart failure, atrial fibrillation, aortic valve stenosis, abdominal aortic aneurysm, stroke, or CVD mortality. However, in never smokers, snus use was associated with a statistically significant increased risk of total and ischemic stroke (HRs [95% confidence intervals] = 1.52 [1.01-2.30] and 1.63 [1.05-2.54], respectively) and non-significantly positively associated with some other CVDs.

CONCLUSIONS

In this middle-aged and elderly Swedish population, current Swedish snus use was not associated with the risk of major heart and valvular diseases, abdominal aortic aneurysm, or CVD mortality in the entire study population, but was linked to an increased risk of stroke in never smokers.

Nicotine and vascular dysfunction

Cigarette smoking is the single most important risk factor for the development of cardiovascular diseases (CVDs). However, the role of nicotine, the addictive component of all tobacco products, in the development of CVD is incompletely understood. Although increased public awareness of the harms of cigarette smoking has successfully led to a decline in its prevalence, the use of electronic cigarettes (e-cig) or electronic nicotine delivery system has increased dramatically in recent years because of the perception that these products are safe. This review summarizes our current knowledge of the expression and function of the nicotinic acetylcholine receptors in the cardiovascular system and the impact of nicotine exposure on cardiovascular health, with a focus on nicotine-induced vascular dysfunction. Nicotine alters vasoreactivity through endothelium-dependent and/or endothelium-independent mechanisms, leading to clinical manifestations in both cigarette smokers and e-cig users. In addition, nicotine induces vascular remodelling through its effects on proliferation, migration and matrix production of both vascular endothelial and vascular smooth muscle cells. The purpose of this review is to identify critical knowledge gaps regarding the effects of nicotine on the vasculature and to stimulate continued nicotine research.

Smoking, Smoking Cessation, and Progression of Chronic Kidney Disease: Results From KNOW-CKD Study

INTRODUCTION

In patients with chronic kidney disease (CKD), studies investigating the association between smoking and deterioration of kidney function are scarce.

AIMS AND METHODS

We analyzed data for 1,951 patients with an estimated glomerular filtration rate (eGFR) ≥15 mL/min/1.73 m2 enrolled in the KoreaN cohort study for Outcome in patients With Chronic Kidney Disease (KNOW-CKD) from 2011 to 2016. Patients were categorized by smoking load. Primary outcome was a composite of a ≥50% reduction in eGFR, initiation of dialysis, or kidney transplantation.

RESULTS

There were 967 never-smokers and 369, 276, and 339 smokers who smoked <15, 15 to 29, ≥30 pack-years, respectively. During a mean follow-up of 3.0 years, the incidence rates (95% confidence interval [CI]) of the primary outcome were 54.3 (46.4-63.5), 46.9 (35.9-61.4), 69.2 (52.9-90.6), and 76.3 (60.7-96.0) events per 1,000 person-yr in never-, <15, 15 to 29, and ≥30 pack-year smokers. In cause-specific hazard model after adjustment of confounding factors, smokers were associated with 1.09 (0.73-1.63), 1.48 (1.00-2.18), and 1.94 (1.35-2.77) fold increased risk (95% CI) of primary outcome in <15, 15-29, and ≥30 pack-year smokers compared with never-smokers. The association of longer smoking duration with higher risk of CKD progression was evident particularly in patients with eGFR < 45 mL/min/1.73 m2 and proteinuria ≥ 1.0 g/g. In contrast, the risk of adverse kidney outcome decreased with longer smoking-free periods among former-smokers.

CONCLUSIONS

These findings suggest potentially harmful effects of the degree of exposure to smoking on the progression of CKD.

IMPLICATIONS

Among patients with CKD, there has been lack of studies on the association between smoking and CKD progression and studies to date have yielded conflicting results. In this prospective cohort study involving Korean CKD patients, smoking was associated with significantly higher risk of worsening kidney function. Furthermore, the risk of adverse kidney outcome was incrementally higher as smoking pack-years were higher. As the duration of smoking cessation increased, the hazard ratios for adverse kidney outcome were attenuated, suggesting that quitting smoking may be a modifiable factor to delay CKD progression.

Nicotine: Regulatory roles and mechanisms in atherosclerosis progression

Smoking is an independent risk factor for atherosclerosis. The smoke produced by tobacco burning contains more than 7000 chemicals, among which nicotine is closely related to the occurrence and development of atherosclerosis. Nicotine, a selective cholinergic agonist, accelerates the formation of atherosclerosis by stimulating nicotinic acetylcholine receptors (nAChRs) located in neuronal and non-neuronal tissues. This review introduces the pathogenesis of atherosclerosis and the mechanisms involving nicotine and its receptors. Herein, we focus on the various roles of nicotine in atherosclerosis, such as upregulation of growth factors, inflammation, and the dysfunction of endothelial cells, vascular smooth muscle cells (VSMC) as well as macrophages. In addition, nicotine can stimulate the generation of reactive oxygen species, cause abnormal lipid metabolism, and activate immune cells leading to the onset and progression of atherosclerosis. Exosomes, are currently a research hotspot, due to their important connections with macrophages and the VSMC, and may represent a novel application into future preventive treatment to promote the prevention of smoking-related atherosclerosis. In this review, we will elaborate on the regulatory mechanism of nicotine on atherosclerosis, as well as the effects of interference with nicotine receptors and the use of exosomes to prevent atherosclerosis development.

The common characteristics and mutual effects of heart failure and atrial fibrillation: initiation, progression, and outcome of the two aging-related heart diseases

Atrial fibrillation (AF) and heart failure (HF) are common chronic diseases noted in humans. AF and HF share several risk factors, such as age, hypertension, obesity, diabetes, and dyslipidemia. They can interact with each other, while both their morbidity and mortality have been considerably increased. And AF and HF often occur together, suggesting a strong association between the two. However, the underlying mechanism behind this association is not well understood. Among them, aging is the most significant common risk factor, which represents an aging heart and is characterized by fibrosis and decreased number of cardiomyocytes, known as senescence-related cardiac remodeling for both atria and ventricles. Finally, it is proposed that cardiac remodeling is the key link between AF and HF.

Does Prenatal Exposure to CNS Stimulants Increase the Risk of Cardiovascular Disease in Adult Offspring?

Prenatal exposure to an adverse uterine environment can have long lasting effects on adult offspring through DNA methylation, histone acetylation, and other epigenetic effects that alter gene expression and physiology. It is well-known that consumption of CNS stimulants such as caffeine, nicotine, amphetamines, and cocaine during pregnancy can adversely impact the offspring. However, most work in this area has focused on neurological and behavioral outcomes and has been limited to assessments in young offspring. The impact of prenatal exposure to these agents on the adult cardiovascular system has received relatively little attention. Evidence from both animal and human studies indicate that exposure to CNS stimulants during the gestational period can negatively impact the adult heart and vasculature, potentially leading to cardiovascular diseases later in life. This review discusses our current understanding of the impact of prenatal exposure to cocaine, methamphetamine, nicotine, and caffeine on the adult cardiovascular system.

National rates and trends of tobacco and substance use disorders among atrial fibrillation hospitalizations

BACKGROUND

Atrial Fibrillation (AF) has been associated with various behavioral risk factors such as tobacco, alcohol, and/or substances abuse.

OBJECTIVE

The main objective is to describe the national trends and burden of tobacco and substance abuse in AF hospitalizations. Also, this study identifies potential population who are more vulnerable to these substance abuse among AF hospitalizations.

METHODS

The National Inpatient Sample database from 2007 to 2015 was utilized and the hospitalizations with AF were identified using the international classification of disease, Ninth Revision, Clinical Modification code. They were stratified into without abuse, tobacco use disorder (TUD), substance use disorder (SUD), alcohol use disorder (AUD) and drug use disorder (DUD).

RESULTS

Of 3,631,507 AF hospitalizations, 852,110 (23.46%) had TUD, 1,851,170 (5.1%) had SUD, 155,681 (4.29%) had AUD and 42,667 (1.17%) had DUD. The prevalence of TUD, SUD, AUD, and DUD was substantially increased across all age groups, races, and gender during the study period. Female sex was associated with lower odds TUD, SUD, AUD, and DUD. Among AF hospitalizations, the black race was associated with higher odds of SUD, and DUD. The younger age group (18-35 years), male, Medicare/Medicaid as primary insurance, and lower socioeconomic status were associated with increased risk of both TUD and SUDs.

CONCLUSION

TUD and SUD among AF hospitalizations in the United States mainly affects males, younger individuals, white more than black, and those of lower socioeconomic status which demands for the development of preventive strategies to address multilevel influences.

Nicotine supplementation enhances simulated game performance of archery athletes

Background

Nicotine is beneficial to mood, arousal and cognition in humans. Due to the importance of cognitive functioning for archery athletes, we investigated the effects of nicotine supplementation on the cognitive abilities, heart rate variability (HRV), and sport performance of professional archers.

Methods

Eleven college archers were recruited and given 2 mg of nicotine supplementation (NIC group) and placebo (PLA group) in a crossover design.

Results

The results showed that at 30 min after the intake of nicotine gum, the “correct rejection” time in the NIC group was significantly lower than that of the PLA group (7.29 ± 0.87 vs. 8.23 ± 0.98 msec, p < 0.05). In addition, the NIC group completed the grooved pegboard test in a shorter time than the PLA group (48.76 ± 3.18 vs. 53.41 ± 4.05 s, p < 0.05), whereas motor reaction times were not different between the two groups. Saliva α-amylase activity was significantly lower after nicotine supplementation (p < 0.01) but increased immediately after the archery test in the NIC group (p < 0.05). In addition, nicotine supplementation significantly decreased HRV and increased the archery score (290.58 ± 10.09 vs. 298.05 ± 8.56, p < 0.01).

Conclusions

Nicotine enhances the performance of archery athletes by increasing cognitive function and stimulating the sympathetic adrenergic system.

Sleep Quality Associated with Habitual Physical Activity Level and Autonomic Nervous System of Smokers

BACKGROUND

Few studies have examined the relationship of one's habitual physical activity level and autonomic nervous system (ANS) modulation on sleep quality in smokers.

OBJECTIVE

The aim of this study was to identify changes in the sleep quality of smokers and its relation with their habitual physical activity level and ANS modulation.

METHODS

Forty-two smokers were divided into two groups according to the 50th percentile of the moderate-to-vigorous physical activity (MVPA). Sleep quality was assessed using the Mini-sleep Questionnaire, and ANS modulation was assessed by indices of heart rate variability (HRV). To examine the possible mean differences, the analysis of covariance (ANCOVA) was used, adjusted for age, sex, body composition, pack-years, beta-blockers, anxiety, and depression in log base 10, not including qualitative data, such as sex and beta-blockers. Correlations were made by using the Spearman rank correlation. The statistical significance was set at 5.

RESULTS

The smokers who were less active showed poor sleep quality (p=0.048) and insomnia (p=0.045). Furthermore, the less active group presented decreased parasympathetic modulation [HF (un; p=0.049); RMSSD (ms; p=0.047) and SD1 (ms; p=0.047)] and an increased LF (un) index (p=0.033) and LF/HF ratio (p=0.040). A positive correlation between the total Mini-sleep score with LF (un) index (r=0.317, p=0.041) and LF/HF ratio (r=0.318, p=0.040) and negative correlation with HF (un) index (r= -0.322, p=0.038).

CONCLUSIONS

Smokers with lower levels of habitual physical activity showed poor sleep quality and alterations in autonomic nervous system modulation; (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0).

Smoking Accelerates Atrioventricular Conduction in Humans Concordant with Increased Dopamine Release

Smoking is associated with cardiac arrhythmia, stroke, heart failure, and sudden cardiac arrest, all of which may derive from increased sympathetic influence on cardiac conduction system and altered ventricular repolarization. However, knowledge of the effects of smoking on supraventricular conduction, and the role of the sympathetic nervous system in them, remains incomplete. Participants with intermediate-high cardiovascular disease risk were measured for urinary catecholamines and cotinine, and 12-lead electrocardiograms (ECGs) were measured for atrial and atrioventricular conduction times, including P duration, PR interval, and PR segment (lead II), which were analyzed for associations with cotinine by generalized linear models. Statistical mediation analyses were then used to test whether any significant associations between cotinine and atrioventricular conduction were mediated by catecholamines. ECG endpoints and urinary metabolites were included from a total of 136 participants in sinus rhythm. Atrial and atrioventricular conduction did not significantly differ between smokers (n = 53) and non-smokers (n = 83). Unadjusted and model-adjusted linear regressions revealed cotinine significantly and inversely associated with PR interval and PR segment, but not P duration. Dopamine, norepinephrine, and epinephrine all inversely associated with PR interval, whereas only dopamine was also inversely associated with PR segment (p < 0.05). Dopamine and norepinephrine (but not epinephrine) also associated positively with cotinine. Dopamine mediated the relationship between cotinine and PR interval, as well as the relationship between cotinine and PR segment. Smoking is associated with accelerated atrioventricular conduction and elevated urinary dopamine and norepinephrine. Smoking may accelerate atrioventricular nodal conduction via increased dopamine production.

Impact of smoking on course and outcome of aneurysmal subarachnoid hemorrhage

Background

While the smoking-related risk of experiencing an aneurysmal subarachnoid hemorrhage (aSAH) is well established, it remains unclear whether smoking has an unexpected “protective effect” in aSAH, or if smokers are more at risk for complications and poor outcomes.

Methods

Prospective, observational study investigating the course and outcome of aSAH in patients admitted during the years 2011 and 2012. Smoking status at admittance, demographic, medical, and radiological variables were registered along with management, complications, and outcome at 1 year in terms of mortality, modified Rankin score, and Glasgow outcome score extended. We compared current smokers with nonsmokers on group level and by paired analysis matched by aSAH severity, age, and severity of vasospasm.

Results

We included 237 patients, thereof 138 current smokers (58.2%). Seventy-four smoker/nonsmoker pairs were matched. Smokers presented more often in poor clinical grade, had less subarachnoid blood, and were younger than nonsmokers. Ruptured aneurysms were larger, and multiple aneurysms more common in smokers. Severe multi-vessel vasospasm was less frequent in smokers, whereas all other complications occurred at similar rates. Mortality at 30 days was lower in smokers and functional outcome was similar in smokers and nonsmokers. Poor clinical grade, age, cerebral infarction, and vertebrobasilar aneurysms were independent predictors of 1-year mortality and of poor functional outcome. Serious comorbidity was a predictor of 1-year mortality. Smoking did not predict mortality or poor functional outcome.

Conclusions

Notwithstanding clinically more severe aSAH, smokers developed less frequently severe vasospasm and had better outcome than expected. The risk for complications after aSAH is not increased in smokers.

Acute effects of electronic cigarettes on arterial pressure and peripheral sympathetic activity in young nonsmokers

Electronic cigarettes (e-cigarettes) are marketed as an alternative to smoking for those who want to decrease the health risks of tobacco. Tobacco cigarettes increase heart rate (HR) and arterial pressure, while reducing muscle sympathetic nerve activity (MSNA) through sympathetic baroreflex inhibition. The acute effects of e-cigarettes on arterial pressure and MSNA have not been reported: our purpose was to clarify this issue. Using a randomized crossover design, participants inhaled on a JUUL e-cigarette containing nicotine (59 mg/mL) and a similar placebo e-cigarette (0 mg/mL). Experiments were separated by ∼1 mo. We recorded baseline ECG, finger arterial pressure (n = 15), and MSNA (n = 10). Subjects rested for 10 min (BASE) and then inhaled once every 30 s on an e-cigarette that contained nicotine or placebo (VAPE) for 10 min followed by a 10-min recovery (REC). Data were expressed as Δ means ± SE from BASE. Heart rate increased in the nicotine condition during VAPE and returned to BASE values in REC (5.0 ± 1.3 beats/min nicotine vs. 0.1 ± 0.8 beats/min placebo, during VAPE; P < 0.01). Mean arterial pressure increased in the nicotine condition during VAPE and remained elevated during REC (6.5 ± 1.6 mmHg nicotine vs. 2.6 ± 1 mmHg placebo, during VAPE and 4.6.0 ± 1.7 mmHg nicotine vs. 1.4 ± 1.4 mmHg placebo, during REC; P < 0.05). MSNA decreased from BASE to VAPE and did not restore during REC (-7.1 ± 1.6 bursts/min nicotine vs. 2.6 ± 2 bursts/min placebo, during VAPE and -5.8 ± 1.7 bursts/min nicotine vs. 0.5 ± 1.4 bursts/min placebo, during REC; P < 0.05). Our results show that acute e-cigarette usage increases mean arterial pressure leading to a baroreflex-mediated inhibition of MSNA.NEW & NOTEWORTHY The JUUL e-cigarette is the most popular e-cigarette in the market. In the present study, inhaling on a JUUL e-cigarette increased mean arterial pressure and heart rate, and decreased muscle sympathetic nerve activity (MSNA). In contrast, inhaling on a placebo e-cigarette without nicotine elicited no sympathomimetic effects. Although previous tobacco cigarette studies have demonstrated increased mean arterial pressure and MSNA inhibition, ours is the first study to report similar responses while inhaling on an e-cigarette. Listen to this article's corresponding podcast at @ https://ajpheart.podbean.com/e/aerosolized-nicotine-and-cardiovascular-control/.

The Effect of Dipping Tobacco on Pulse Wave Analysis among Adult Males

BACKGROUND

The current study investigated the effect of dipping tobacco (DT) use on arterial wall stiffness which is a known marker of increased risk of cardiovascular events.

METHODS

A case-control study which included 101 adult males was carried out in Al-Shaab Teaching Hospital. Blood pressure and pulse wave analysis parameters were recorded in 51 DT users (study group) before and after 30 minutes of placing tobacco and in 50 nontobacco users (control group). Anthropometric measurements were collected using data collection sheet. Data were entered into a computer and analyzed by using the software Statistical Package for the Social Sciences (SPSS) version 20 (SPSS Inc., Chicago, IL, USA).

RESULTS

At baseline measurements, heart rate (HR) was significantly lower in the study group compared to the control group (66.15 ± 9.21 vs. 72.87 ± 10.13 beats/min; P value ≤ 0.001). Subendocardial viability ratio (SEVR) was significantly higher in the study group compared to the control group (203.44 ± 30.34 vs. 179.11 ± 30.51%; P value ≤ 0.001). Acute effects of DT compared to pretobacco dipping showed significant increase in HR (72.50 ± 10.89 vs. 66.15 ± 9.21 beats/min; P value ≤ 0.001) and significant decrease in augmentation pressure (AP) (4.30 (2.30-8.00) vs. 3.30 (0.60-6.3) mmHg; P value ≤ 0.001), ejection duration (ED) (271.65 ± 19.42 vs. 279.53 ± 20.47 ms; P value ≤ 0.001), and SEVR (187.11 ± 29.81 vs. 203.44 ± 30.34; P value ≤ 0.001). Linear regression analysis for AP predictor showed that only HR and AIx@75 affect and predict the values of AP (Beta ± SE; -0.242 ± 0.019, P value ≤ 0.001; 0.685 ± 0.014, P value ≤ 0.001).

CONCLUSIONS

Long-term use of DT was not associated with permanent changes in heart rate and blood pressure. Acute tobacco dipping caused an acute increase in heart rate and oxygen demands of myocardium.

The "Road" to Atrial Fibrillation: The Role of the Cardiac Autonomic Nervous System

At the population level, there is a parallel escalation in the healthcare burden of both, atrial fibrillation (AF) as well its risk factors. Compounding this relationship, AF is associated with escalating burden at an individual level, due its self-perpetuating and progressive nature. The mechanisms by which these risk factors interact to produce atrial remodelling and subsequent AF are unclear. This intersection is critical to the development of strategies to combat this disease at both the individual and population-level. It is well known that AF can manifest from disturbances in autonomic activity. At the population level, there is growing data to suggest a role of the autonomic nervous system in the future incidence of AF. Here, we provide an overview of the association of cardiac autonomic dysfunction with the incidence of AF, review the role of the autonomic nervous system (ANS) as an intermediary between risk factors and the development of AF and finally, we discuss the bidirectional relationship between AF and cardiac autonomic nervous system dysfunction; to determine whether this is implicated in the progression of AF.

Voltage and e-liquid composition affect nicotine deposition within the oral cavity and carbonyl formation

INTRODUCTION

The diversity of e-liquids along with higher powered e-cigarette nicotine delivery devices are increasing. This study evaluated the effect of voltage and e-liquid composition on particle size, nicotine deposition in a human oral-trachea cast model and generation of carbonyls.

METHODS

Nineteen e-liquids were evaluated for 30 common chemicals by gas chromatography-mass spectrometry (GC-MS). E-cigarette aerosols containing nicotine (1.2%) were generated at 4 and 5 volts for assessment of particle size distribution using Aerodynamic Particle Sizer (APS), Fast Mobility Particle Size (FMPS) and an In-Tox cascade impactor and nicotine deposition by GC-MS. Carbonyl formation in aerosols was assessed by liquid chromatography tandem triple-quad mass spectrometry.

RESULTS

Total chemical burden ranged from 0.35 to 14.6 mg/mL with ethyl maltol present in all e-liquids. Increasing voltage was associated with an increase in median size of aerosol particles and the deposition of nicotine in the oral cast. Two e-liquids caused a 2.5-fold to 5-fold increase in nicotine deposition independent of particle size and voltage. Increasing voltage caused an increase in formaldehyde, acetaldehyde and acrolein in the presence and absence of nicotine. Most striking, aerosols from several e-liquids significantly increased levels of acetaldehyde and acrolein compared with unflavoured.

CONCLUSIONS

Increasing voltage and composition of e-liquid can increase the exposure of the oral pharynx and bronchial airways to carbonyls that can react with DNA to generate adducts, induce oxidative stress, inflammation and cell death. The elevated nicotine and carbonyls readily enter the circulation where they can also cause cardiovascular stress. The growing popularity of higher voltage e-cigarette delivery devices will likely further elevate health risks from chronic exposure to these complex aerosols.

Recent findings in the pharmacology of inhaled nicotine: Preclinical and clinical in vivo studies

INTRODUCTION

The rise of vaping in adolescents, the recent entrance of new inhaled nicotine products such as iQOS on the market and e-cigarette or vaping product use-associated lung injury cases has created concern for the use of inhaled non-combustible nicotine products. This narrative review discusses recent experimental in vivo studies that utilize human, rat and mouse models to understand the pharmacological impact of nicotine from non-combustible products.

METHODS

The search engine PubMed was utilized with the following search terms: inhaled nicotine, nicotine e-cigarette, heated tobacco products, iQOS, electronic cigarette, nicotine inhaler, nicotine vaping. This review highlights recent primary in vivo studies of inhaled nicotine administration experimental paradigms that occurred in laboratory settings using human and rodent (rats and mice) models that have been published from January 2017-December 2019.

RESULTS

The pharmacokinetics of nicotine via e-cigarettes is influenced by the PG/VG and flavor constituents in e-liquids, the presence of nicotine salts in e-liquids, puff topography of nicotine and tobacco product users and the power of the e-cigarette device. The pharmacodynamic impact of inhaled nicotine has cardiovascular, pulmonary and central nervous system implications.

CONCLUSION

The articles reviewed here highlight the importance of both animal and human models to fully understand the impact of inhaled nicotine pharmacology There is a need for more rodent pharmacokinetic inhaled nicotine studies to understand the influences of factors such as flavor and nicotine salts. Additionally, consensus on nicotine measurement in both human and rodent studies is greatly needed.

Acute and chronic sympathomimetic effects of e-cigarette and tobacco cigarette smoking: role of nicotine and non-nicotine constituents

Electronic cigarettes (ECs) and tobacco cigarettes (TCs) both release nicotine, a sympathomimetic drug. We hypothesized that baseline heart rate variability (HRV) and hemodynamics would be similar in chronic EC and TC smokers and that after acute EC use, changes in HRV and hemodynamics would be attributable to nicotine, not non-nicotine, constituents in EC aerosol. In 100 smokers, including 58 chronic EC users and 42 TC smokers, baseline HRV and hemodynamics [blood pressure (BP) and heart rate (HR)] were compared. To isolate the acute effects of nicotine vs. non-nicotine constituents in EC aerosol, we compared changes in HRV, BP, and HR in EC users after using an EC with nicotine (ECN), EC without nicotine (EC0), nicotine inhaler (NI), or sham vaping (control). Outcomes were also compared with TC smokers after smoking one TC. Baseline HRV and hemodynamics were not different in chronic EC users and TC smokers. In EC users, BP and HR, but not HRV outcomes, increased only after using the ECN, consistent with a nicotine effect on BP and HR. Similarly, in TC smokers, BP and HR but not HRV outcomes increased after smoking one TC. Despite a similar increase in nicotine, the hemodynamic increases were significantly greater after TC smokers smoked one TC compared with the increases after EC users used the ECN. In conclusion, chronic EC and TC smokers exhibit a similar pattern of baseline HRV. Acute increases in BP and HR in EC users are attributable to nicotine, not non-nicotine, constituents in EC aerosol. The greater acute pressor effects after TC compared with ECN may be attributable to non-nicotine, combusted constituents in TC smoke.NEW & NOTEWORTHY Chronic electronic cigarette (EC) users and tobacco cigarette (TC) smokers exhibit a similar level of sympathetic nerve activity as estimated by heart rate variability. Acute increases in blood pressure (BP) and heart rate in EC users are attribute to nicotine, not non-nicotine, constituents in EC aerosol. Acute TC smoking increased BP significantly more than acute EC use, despite similar increases in plasma nicotine, suggestive of additional adverse vascular effects attributable to combusted, non-nicotine constituents in TC smoke.

History repeats itself: Role of characterizing flavors on nicotine use and abuse

The popularity of e-cigarettes has skyrocketed in recent years, and most vapers use flavored e-cigarette products. Consumption of flavored e-cigarettes exceeds that of combustible cigarettes and other tobacco products among adolescents, who are particularly vulnerable to becoming nicotine dependent. Flavorings have been used by the tobacco industry since the 17th century, but the use of flavors by the e-cigarette industry to create products with "characterizing" flavors (i.e. flavors other than tobacco or menthol) has sparked a public health debate. This review addresses the possibility that characterizing flavors make nicotine more appealing, rewarding and addictive. It also discusses ways in which preclinical and clinical studies could improve our understanding of the mechanisms by which flavors may alter nicotine reward and reinforcement. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.