Nicotine and sympathetic neurotransmission

Cardiovascular autonomic effects of electronic cigarette use: a systematic review

Purpose

Electronic cigarettes (ECs) are the fastest growing tobacco product in the USA, and ECs, like tobacco cigarettes (TCs), have effects on the cardiovascular autonomic nervous system, with clinical implications. The purpose of this review was to collect and synthesize available studies that have investigated the autonomic cardiovascular effects of EC use in humans. Special attention is paid to the acute and chronic effects of ECs, the relative contributions of the nicotine versus non-nicotine constituents in EC emissions and the relative effects of ECs compared to TCs.

Methods

Using the methodology described in the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement, we conducted a literature search of the Ovid PubMed and Embase databases on 6 December 2019 using keywords in titles and abstracts of published literature. Acute (minutes to hours) and chronic (days or longer) changes in heart rate variability (HRV), heart rate (HR) and blood pressure (BP) were used as estimates of cardiovascular autonomic effects.

Results

Nineteen studies were included in this systematic review, all of which used earlier generation EC devices. Acute EC vaping increased HR and BP less than acute TC smoking. Nicotine but not non-nicotine constituents in EC aerosol were responsible for the sympathoexcitatory effects. The results of chronic EC vaping studies were consistent with a chronic sympathoexcitatory effect as estimated by HRV, but this did not translate into chronic increases in HR or BP.

Conclusions

Electronic cigarettes are sympathoexcitatory. Cardiac sympathoexcitatory effects are less when vaping using the earlier generation ECs than when smoking TCs. Additional studies of the latest pod-like EC devices, which deliver nicotine similarly to a TC, are necessary.

Electronic supplementary material

The online version of this article (10.1007/s10286-020-00683-4) contains supplementary material, which is available to authorized users.

Conscious Abstinence from Smokeless Tobacco Evokes Higher Withdrawal Response and Impairs Cognitive Performance Independent of Sympathetic Response

INTRODUCTION

High consumption of smokeless tobacco in adult Indian population increases the risk of developing oral cancers leading to high morbidity and mortality. Though the influence of abstinence from smoking on cognitive performance has been widely studied, the effect of smokeless tobacco on cognitive performance and its association with withdrawal symptoms is less understood. This study comparatively investigates the effect of short-term conscious abstinence and distraction during abstinence from smokeless tobacco consumption on the craving, withdrawal symptoms, sympathetic response, and cognitive performance in tobacco addicts.

METHODS

Age, sex, education and socioeconomic status matched control (N = 15) and smokeless tobacco addicts (N = 60) were recruited from residential areas in Bhubaneswar for the study. Following randomization of the addicts, conscious abstinence (N = 30) was induced by informed abstinence from tobacco consumption for 8 hours, while distracted cessation (N = 30) was induced by involving the participants in a cognitively engaging task for 8 hours during uninformed tobacco abstinence.

RESULTS

The results of the study show higher withdrawal symptoms and reduced cognitive performance in volunteers with conscious abstinence which was positively correlated. The decreased cognitive performance in conscious cessation was independent of tobacco-induced increase in the LF:HF ratio and cotinine concentration in saliva.

CONCLUSION

While conscious abstinence results in higher withdrawal symptoms, distraction during abstinence lowers these symptoms. Inclusion of distraction sessions during cessation can, therefore, be a new element in tobacco control strategies.

Nicotine instigates podocyte injury via NLRP3 inflammasomes activation

Background/Aims: Recent studies have shown that nicotine induces podocyte damage. However, it remains unknown how nicotine induces podocyte injury. The present study tested whether nicotine induces NLRP3 inflammasomes activation and thereby contributes to podocyte injury.

Results: Nicotine treatment significantly increased the colocalization of NLRP3 with Asc, caspase-1 activity, IL-β production, cell permeability in podocytes compared to control cells. Pretreatment with caspase-1 inhibitor, WEHD significantly abolished the nicotine-induced colocalization of NLRP3 with Asc, caspase-1 activity, IL-1β production and cell permeability in podocytes. Immunofluorescence analysis showed that nicotine treatment significantly decreased the podocin and nephrin expression compared to control cells. However, prior treatment with WEHD attenuated the nicotine-induced podocin and nephrin reduction. In addition, we found that nicotine treatment significantly increased the O₂^.- production compared to control cells. However, prior treatment with WEHD did not alter the nicotine-induced O₂^.- production. Furthermore, prior treatment with ROS scavenger, NAC significantly attenuated the nicotine-induced caspase-1 activity, IL-1β production, podocin and nephrin reduction in podocytes.

Conclusions: Nicotine-induced the NLRP3 inflammasome activation in podocytes and thereby results in podocyte injury.

Methods: Inflammasome formation and immunofluorescence expressions were quantified by confocal microscopy. Caspase-1 activity, IL-1β production and O₂^.- production were measured by ELISA and ESR.

Associations Between Risk Factors and Overactive Bladder: A Meta-analysis

Age and body mass index are associated with increased risks of overactive bladder, whereas employment status is associated with a decreased risk of overactive bladder.

Objective

The purpose of this study was to investigate the risk factors of overactive bladder (OAB).

Methods

The PubMed, Embase, and Cochrane Library databases were retrieved through May 2016. Odds ratios (OR) or standard mean differences (SMDs) with 95% confidence intervals (CIs) were used to evaluate the associations between risk factors and OAB. Heterogeneity among studies was examined using χ² test based on the Q and I² tests.

Results

A total of 28 articles were analyzed in our study. The results suggested that age and body mass index were significantly higher in OAB patients than in non-OAB controls (SMDs [95% CIs], 0.30 [0.19–0.41] and 0.39 [0.24–0.53]). A significant negative association was found between employment status and OAB (OR [95% CIs], 0.64 [0.46–0.90]). However, sex, educational level, parity, vaginal delivery, race, menopause, marital status, smoking, and alcohol consumption were not significantly different in OAB and non-OAB control patients (ORs [95% CIs], 0.95 [0.59–1.55], 1.04 [0.82, 1.33], 0.98 [0.56–1.70], 1.66 [0.90–3.07], 0.98 [0.75–1.28], 1.84 [0.23–14.70], 0.97 [0.78–1.19], 0.91 [0.77–1.08], and 0.88 [0.71–1.09], respectively). In addition, the number of parities and vaginal deliveries in OAB patients also showed no significant differences compared with non-OAB control patients (SMDs [95% CI], 0.05 [−0.27 to 0.38] and −0.16 [0.40 to 0.09]).

Conclusions

This meta-analysis suggests that age and body mass index are associated with increased risks of OAB, whereas employment status is associated with a decreased risk of OAB. Further prospective studies with large sample sizes are needed to confirm this conclusion.

Childhood Tobacco Smoke Exposure and Risk of Atrial Fibrillation in Adulthood

BACKGROUND

Cigarette smoking is known to increase the risk of atrial fibrillation (AF), and a recent cross-sectional analysis suggested that parental smoking may be an AF risk factor.

OBJECTIVES

The purpose of this study was to assess if parental smoking predicts offspring AF in the Framingham Heart Study.

METHODS

This study analyzed Framingham Offspring cohort participants with parents in the Original cohort with known smoking status during the offspring's childhood. Framingham participants were evaluated every 2 to 8 years and were under routine surveillance for incident AF. The authors assessed AF incidence among Offspring participants exposed to parental smoking through age 18 years and performed a mediation analysis to determine the extent to which offspring smoking might explain observed associations.

RESULTS

Of 2,816 Offspring cohort participants with at least 1 parent in the Original cohort, 82% were exposed to parental smoking. For every pack/day increase in parental smoking, there was an 18% increase in offspring AF incidence (adjusted hazard ratio [HR]: 1.18; 95% confidence interval [CI]: 1.00 to 1.39; p = 0.04). Additionally, parental smoking was a risk factor for offspring smoking (adjusted odds ratio [OR]: 1.34; 95% CI: 1.17 to 1.54; p < 0.001). Offspring smoking mediated 17% (95% CI: 1.5% to 103.3%) of the relationship between parental smoking and offspring AF.

CONCLUSIONS

Childhood secondhand smoke exposure predicted increased risk for adulthood AF after adjustment for AF risk factors. Some of this relationship may be mediated by a greater propensity among offspring of smoking parents to smoke themselves. These findings highlight potential new pathways for AF risk that begin during childhood, offering new evidence to motivate smoking avoidance and cessation.

Biological effects of nicotine exposure: A narrative review of the scientific literature

The emergence of new tobacco heating products and electronic nicotine delivery systems (ENDS) is changing the way humans are exposed to nicotine. The purpose of this narrative review is to provide a broad overview of published scientific literature with respect to the effects of nicotine on three key health-related areas: 1) cardiovascular risk, 2) carcinogenesis and 3) reproductive outcomes. These areas are known to be particularly vulnerable to the effects of cigarette smoke, and in addition, nicotine has been hypothesized to play a role in disease pathogenesis. Acute toxicity will also be discussed. The literature to February 2019 suggests that there is no increased cardiovascular risk of nicotine exposure in consumers who have no underlying cardiovascular pathology. There is scientific consensus that nicotine is not a direct or complete carcinogen, however, it remains to be established whether it plays some role in human cancer propagation and metastasis. These cancer progression pathways have been proposed in models in vitro and in transgenic rodent lines in vivo but have not been demonstrated in cases of human cancer. Further studies are needed to determine whether nicotine is linked to decreased fertility in humans. The results from animal studies indicate that nicotine has the potential to act across many mechanisms during fetal development. More studies are needed to address questions regarding nicotine exposure in humans, and this may lead to additional guidance concerning new ENDS entering the market.

Cardiovascular, carcinogenic and reproductive effects of nicotine exposure: A narrative review of the scientific literature

The emergence of new tobacco heating products and electronic nicotine delivery systems (ENDS) is changing the way humans are exposed to nicotine. The purpose of this narrative review is to provide a broad overview of published scientific literature with respect to the effects of nicotine on three key health-related areas: 1) cardiovascular risk, 2) carcinogenesis and 3) reproductive outcomes. These areas are known to be particularly vulnerable to the effects of cigarette smoke, and in addition, nicotine has been hypothesized to play a role in disease pathogenesis. Acute toxicity will also be discussed. The literature to February 2019 suggests that there is no increased cardiovascular risk of nicotine exposure in consumers who have no underlying cardiovascular pathology. There is scientific consensus that nicotine is not a direct or complete carcinogen, however, it remains to be established whether it plays some role in human cancer propagation and metastasis. These cancer progression pathways have been proposed in models in vitro and in transgenic rodent lines in vivo but have not been demonstrated in cases of human cancer. Further studies are needed to determine whether nicotine is linked to decreased fertility in humans. The results from animal studies indicate that nicotine has the potential to act across many mechanisms during fetal development. More studies are needed to address questions regarding nicotine exposure in humans, and this may lead to additional guidance concerning new ENDS entering the market.

The Effects of Transdermal Nicotine Patches on the Cardiorespiratory and Lactate Responses During Exercise from Light to Moderate Intensity: Implications for Exercise Prescription during Smoking Cessation

Background and objectives: Exercise can help ease withdrawal symptoms of smokers. However, there is little information about the physiological responses, such as cardiorespiratory and lactate (La) responses, during exercise from light to moderate intensity combined with transdermal nicotine patches (TNPs) in smokers. This study aimed to investigate the effect of TNPs on the cardiorespiratory and La responses during exercise at light to moderate intensity. Materials and Methods: Fourteen young men (8 non-smokers, 6 current smokers) aged 20 to 26 years participated in this study. They performed an incremental graded submaximal exercise test using an electromagnetic cycle ergometer set from 30 to 210 W with (TNP condition) or without a TNP (control condition) in a random order. The TNP was applied to the left arm 8–10 h prior to starting the exercise to achieve the peak level of blood nicotine concentration. Heart rate (HR), rate of perceived exertion (RPE), oxygen consumption (VO₂), ventilation (VE), and blood La at rest and during exercise were measured and analyzed. Results: The HR at rest was significantly higher in the TNP condition than in the control condition (TNP; 74.7 ± 13.8 bpm, control; 65.3 ± 10.8 bpm, p < 0.001). There was no interaction (condition × exercise intensity) between any of the variables, and VO₂, VE, RPE, and La during exercise were not significantly different between the conditions. However, HR during exercise was 6.7 bpm higher on average in the TNP condition. Conclusions: The HR during exercise was greater at light to moderate intensity with a TNP. Our study results will guide clinicians or health professionals when prescribing exercise programs combined with TNPs for healthy young smokers.

Electronic cigarettes in the indoor environment

The use of electronic cigarettes (e-cigarettes or "vaping") has seen an unprecedented increase worldwide. Vaping has been promoted as a beneficial smoking cessation tool and an alternative nicotine delivery device that contains no combustion by-products. However, nicotine is highly addictive, and the increased use of nicotine-containing e-cigarettes among teens and individuals who are not in need of smoking cessation may lead to overall greater nicotine dependence in the population. Furthermore, available research indicates that vaping solutions and their emissions may contain much more than just nicotine, including aerosolized flavorings, propylene glycol (PG), and other intentional and unintentional contaminants. These materials could present undefined potential health hazards to both e-cigarette users and bystanders, the full extent of which is not well understood at this time. Whereas e-cigarette usage and exposures may lower some or most of the risks associated with conventional cigarette use, the health effects of nicotine and aerosol exposures from e-cigarettes are not well understood. Research indicates that vaping aerosols are not benign, especially for nearby people in areas with limited ventilation and people with compromised health conditions. In addition, e-juice liquids have already been responsible for an increase in accidental poisonings in children. Because the magnitude of health and safety hazards that vaping may present to nonusers remains unclear, it is prudent to manage and control vaping in indoor locations where smoking is currently restricted. Based on a review of current scientific information, the American Industrial Hygiene Association (AIHA) recommends that e-cigarettes should be considered a source of aerosols, volatile organic compounds (VOCs), and particulates in the indoor environment that have not been thoroughly characterized or evaluated for health risk or safety.

Inhibitory role of Gi-coupled receptors on cAMP-driven cancers with focus on opioid receptors in lung adenocarcinoma and its stem cells

The development, progression, metastasis and drug resistance of the most common human cancers are driven by cyclic adenosine monophosphate (cAMP)-signaling downstream of beta-adrenergic receptors (β-Ars) coupled to the stimulatory G-protein G_s. Receptors coupled to the inhibitory G-protein G_i inhibit this signaling cascade by blocking the activation of the enzyme adenylyl cyclase that catalyzes the formation of cAMP and function as the physiological inhibitors of this signaling cascade. Members of the G_i-coupled receptor family widely expressed in the mammalian organism are GABA B receptors (GABA_B-Rs) for the inhibitory neurotransmitter γ-aminobutyric acid (GABA), opioid receptors for endogenous opioid peptides and cannabinoid receptors for endogenous cannabinoids. This review summarizes current evidence for the concept that the activation of G_i-receptor signaling by pharmacological and psychological means is a promising tool for the long-term management of cAMP-driven cancers with special emphasis on the inhibitory effects of opioids on lung adenocarcinoma and its stem cells.

Increased Cardiac Sympathetic Activity and Oxidative Stress in Habitual Electronic Cigarette Users: Implications for Cardiovascular Risk

Importance

Electronic cigarettes (e-cigarettes) have gained unprecedented popularity, but virtually nothing is known about their cardiovascular risks.

Objective

To test the hypothesis that an imbalance of cardiac autonomic tone and increased systemic oxidative stress and inflammation are detectable in otherwise healthy humans who habitually use e-cigarettes.

Design, Setting, and Participants

Cross-sectional case-control study of habitual e-cigarette users and nonuser control individuals from 2015 to 2016 at the University of California, Los Angeles. Otherwise healthy habitual e-cigarette users between the ages of 21 and 45 years meeting study criteria, including no current tobacco cigarette smoking and no known health problems or prescription medications, were eligible for enrollment. Healthy volunteers meeting these inclusion criteria who were not e-cigarette users were eligible to be enrolled as control individuals. A total of 42 participants meeting these criteria were enrolled in the study including 23 self-identified habitual e-cigarette users and 19 self-identified non-tobacco cigarette, non-e-cigarette user control participants.

Main Outcomes and Measures

Heart rate variability components were analyzed for the high-frequency component (0.15-0.4 Hz), an indicator of vagal activity, the low-frequency component (0.04-0.15 Hz), a mixture of both vagal and sympathetic activity, and the ratio of the low frequency to high frequency, reflecting the cardiac sympathovagal balance. Three parameters of oxidative stress were measured in plasma: (1) low-density lipoprotein oxidizability, (2) high-density lipoprotein antioxidant/anti-inflammatory capacity, and (3) paraoxonase-1 activity.

Results

Of the 42 participants, 35% were women, 35% were white, and the mean age was 27.6 years. The high-frequency component was significantly decreased in the e-cigarette users compared with nonuser control participants (mean [SEM], 46.5 [3.7] nu vs 57.8 [3.6] nu; P = .04). The low-frequency component (mean [SEM], 52.7 [4.0] nu vs 39.9 [3.8] nu; P = .03) and the low frequency to high frequency ratio (mean [SEM], 1.37 [0.19] vs 0.85 [0.18]; P = .05) were significantly increased in the e-cigarette users compared with nonuser control participants, consistent with sympathetic predominance. Low-density lipoprotein oxidizability, indicative of the susceptibility of apolipoprotein B-containing lipoproteins to oxidation, was significantly increased in e-cigarette users compared with nonuser control individuals (mean [SEM], 3801.0 [415.7] U vs 2413.3 [325.0] U; P = .01) consistent with increased oxidative stress, but differences in high-density antioxidant/anti-inflammatory capacity and paraoxonase-1 activity were not significant.

Conclusions and Relevance

In this study, habitual e-cigarette use was associated with a shift in cardiac autonomic balance toward sympathetic predominance and increased oxidative stress, both associated with increased cardiovascular risk.

Recent Trends in the Quantification of Biogenic Amines in Biofluids as Biomarkers of Various Disorders: A Review

Biogenic amines (BAs) are bioactive endogenous compounds which play a significant physiological role in many cell processes like cell proliferation and differentiation, signal transduction and membrane stability. Likewise, they are important in the regulation of body temperature, the increase/decrease of blood pressure or intake of nutrition, as well as in the synthesis of nucleic acids and proteins, hormones and alkaloids. Additionally, it was confirmed that these compounds can be considered as useful biomarkers for the diagnosis, therapy and prognosis of several neuroendocrine and cardiovascular disorders, including neuroendocrine tumours (NET), schizophrenia and Parkinson's Disease. Due to the fact that BAs are chemically unstable, light-sensitive and possess a high tendency for spontaneous oxidation and decomposition at high pH values, their determination is a real challenge. Moreover, their concentrations in biological matrices are extremely low. These issues make the measurement of BA levels in biological matrices problematic and the application of reliable bioanalytical methods for the extraction and determination of these molecules is needed. This article presents an overview of the most recent trends in the quantification of BAs in human samples with a special focus on liquid chromatography (LC), gas chromatography (GC) and capillary electrophoresis (CE) techniques. Thus, new approaches and technical possibilities applied in these methodologies for the assessment of BA profiles in human samples and the priorities for future research are reported and critically discussed. Moreover, the most important applications of LC, GC and CE in pharmacology, psychology, oncology and clinical endocrinology in the area of the analysis of BAs for the diagnosis, follow-up and monitoring of the therapy of various health disorders are presented and critically evaluated.

Chronic exposure to e-cig aerosols during early development causes vascular dysfunction and offspring growth deficits

Increasing popularity of electronic cigarettes (e-cigs), including among women of reproductive age, is attributed to its perceived safety compared to conventional tobacco. However, there is a major knowledge gap surrounding the effects of e-cig aerosols on pregnancy and fetal development. We aimed to evaluate the effects of vaping e-cigs during gestation on offspring growth and to asses if growth deficits are accompanied by altered maternal and fetal vascular hemodynamics. Sprague-Dawley dams were assigned to Pair-Fed Control, Pair-Fed Juice, or Juice+Nicotine groups, and then underwent either a prenatal or prenatal+postnatal exposure paradigm in a custom-engineered vaping system. Mass spectrometry identified major aerosolized constituents from e-cig vaping. The Juice+Nicotine group exhibited significantly decreased fetal weight and crown-rump length (↓46.56%, and ↓23.83%, respectively). Pre- and postnatal exposure to Juice+Nicotine resulted in decreased pup weight at postnatal day (PND) 4-10. Crown-rump length was decreased by 24.71% on PND 10. Blood flow in the Juice+Nicotine group was decreased in the maternal uterine and fetal umbilical circuits by 49.50% and 65.33%, respectively. We conclude that chronic exposure to e-cig aerosols containing nicotine during early development can have deleterious health effects on the exposed offspring. Vaping e-cigs containing nicotine during pregnancy lead to a reduction in offspring weight and crown-rump length, associated with a marked decrease in blood flow in both the maternal uterine and fetal umbilical circulation (a strong indicator of growth restriction). Thus, chronic exposure to e-cig aerosols containing nicotine can lead to potentially harmful developmental effects in early life.

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.

The imminent epidemic of atrial fibrillation and its concomitant diseases - Myocardial infarction and heart failure - A cause for concern

Atrial fibrillation (AF) is increasingly common in the general population. It often coincides with myocardial infarction (MI) and heart failure (HF) which are also diseases in older adults. All three conditions share common cardiovascular risk factors. While hypertension and obesity are central risk factors for all three diseases, smoking and diabetes appear to have less impact on AF. To date, age is the single most important risk factor for AF in the general population. Further, epidemiological studies suggest a strong association of AF to MI and HF. The underlying pathophysiological mechanisms are complex and not fully understood. Both MI and HF can trigger development of AF, mainly by promoting structural and electrical atrial remodeling. On the other hand, AF facilitates HF and MI development via multiple mechanisms, resulting in a vicious circle of cardiac impairment and adverse cardiovascular prognosis. Consequently, to prevent and treat the coincidence of AF and HF or MI a strict optimization of cardiovascular risk factors is required.

Nicotine: Sporting Friend or Foe? A Review of Athlete Use, Performance Consequences and Other Considerations

Nicotine use amongst athletes is high and increasing, especially in team sports. This narrative review examines the rationale behind its use and evidence of its effect on physical performance, and considers important factors that should determine future research efforts. To date, ten studies have assessed muscular strength and power, sub- or maximal endurance and high-intensity exercise when nicotine (medication) or smokeless tobacco was used as an intervention. Two studies observed an ergogenic effect, one an ergolytic with the remaining seven reporting no change. These studies have notable limitations and confounding factors that include participant tolerance to nicotine, interindividual responses, the nicotine delivery system used and failure to adhere to rigorous experimental/scientific design. Further research is encouraged to address these limitations and determine the extent to which anti-doping and governing bodies should consider promoting, coordinating and monitoring any effort against nicotine and nicotine-containing substances in sports.

Association between serum cotinine levels and electrocardiographic left atrial abnormality

BACKGROUND

Although the harmful effect of tobacco exposure on cardiovascular disease (CVD) and its risk factors are well established, the constituents of cigarette-smoke and the pathophysiological mechanism involved are unknown. Recently, deep terminal negativity of P wave in V1 (DTNPV1) has emerged as a marker of left atrial abnormality that predicts atrial fibrillation, stroke, and death due to all-cause or CVD. Therefore, we examined the association between serum cotinine levels with abnormal DTNPV1 using the Third National Health and Nutrition Examination Survey.

METHODS

This analysis included 4,507 participants (mean age 58 ± 13 years, 53% women, 49% non-Hispanic white) of NHANES III, without history of CVD or major electrocardiographic abnormalities and not on heart rate modifying medications. Multivariable logistic regression analysis was used to examine the association between serum cotinine and abnormal DTNPV1-defined from automatically processed electrocardiograms as values of the amplitude of the terminal negative phase of P wave in lead V1 exceeding 100 μV.

RESULTS

Abnormal DTNPV1 was detected in 2.3% (n = 105) of the participants. In a model adjusted for demographics and CVD risk factors, each 10 ng/ml serum cotinine was associated with 2% increased odds of abnormal DTNPV1 (odds ratio 1.02, 95% confidence interval 1.01-1.03, p-value < 0.001). This association was consistent in subgroups stratified by age, sex, race, smoking status, hypertension, diabetes, dyslipidemia, and chronic obstructive pulmonary disease.

CONCLUSION

Elevated serum cotinine levels are associated with an abnormal DTNPV1. This suggests that nicotine exposure can lead to left atrial abnormalities, a possible mechanism for increased risk of CVD.

Biochemical, demographic, and self-reported tobacco-related predictors of the acute heart rate response to nicotine in smokers

Understanding the stimulatory effects of nicotine on cardiovascular function in humans is of great interest given the wide-spread use of different forms of combustible and smokeless products that deliver nicotine. An intravenous nicotine infusion procedure was used to evaluate factors associated with the acute heart rate (HR) response to nicotine (0.5 mg per 70 kg bodyweight) in a sample of 213 smokers. We tested for differential response to nicotine based on demographic characteristics (race [European American vs African America], sex, body mass index and age); a set of blood-based biomarkers (baseline nicotine, cotinine and cortisol levels and nicotine metabolite ratio); and a set of self-reported measures related to tobacco use. Nicotine infusion was first noted to increase HR approximately 10 beats per minute (95% CI: 7.8-12.3) one minute post-infusion, and 13 beats per minute (95% CI: 11.0-15.2) two minutes post-infusion. Higher cortisol, lower nicotine levels, higher nicotine metabolite ratio, being female and greater withdrawal symptoms were independently associated with a potentiated increase in HR 1 or 2 min after nicotine infusion. Factors associated with the acute HR effects of nicotine warrant further investigation given their potential to inform the development of nicotine delivery systems as tobacco harm reduction approaches for smokers.

Tobacco smoking and the risk of atrial fibrillation: A systematic review and meta-analysis of prospective studies

Background

Epidemiological studies on smoking and atrial fibrillation have been inconsistent, with some studies showing a positive association while others have found no association. It is also unclear whether there is a dose–response relationship between the number of cigarettes smoked or pack-years and the risk of atrial fibrillation. We conducted a systematic review and meta-analysis to clarify the association.

Design

Systematic review and meta-analysis.

Methods

We searched the PubMed and Embase databases for studies of smoking and atrial fibrillation up to 20 July 2017. Prospective studies and nested case–control studies within cohort studies reporting adjusted relative risk estimates and 95% confidence intervals (CIs) of atrial fibrillation associated with smoking were included. Summary relative risks (95% CIs) were estimated using a random effects model.

Results

Twenty nine prospective studies (22 publications) were included. The summary relative risk was 1.32 (95% CI 1.12–1.56, I2 = 84%, n = 11 studies) for current smokers, 1.09 (95% CI 1.00–1.18, I2 = 33%, n = 9) for former smokers and 1.21 (95% CI 1.12–1.31, I2 = 80%, n = 14) for ever smokers compared to never smokers. Comparing current versus non-current smokers the summary relative risk was 1.33 (95% CI 1.14–1.56, I2 = 78%, n = 10). The summary relative risk was 1.14 (95% CI 1.10–1.20, I2 = 0%, n = 3) per 10 cigarettes per day and 1.16 (95% CI 1.09–1.25, I2 = 49%, n = 2) per 10 pack-years and there was no evidence of a non-linear association for cigarettes per day, Pnon-linearity = 0.17.

Conclusions

The current meta-analysis suggests that smoking is associated with an increased risk of atrial fibrillation in a dose-dependent matter, but the association is weaker among former smokers compared to current smokers.

Effect of nicotine on placental ischemia-induced complement activation and hypertension in the rat

Preeclampsia is a pregnancy-specific condition manifested by new-onset maternal hypertension with systemic inflammation, including increased innate immune system complement activation. While exact pathophysiology is unknown, evidence suggests that inadequate spiral artery invasion and resulting utero-placental insufficiency is the initiating event. Cigarette smoking during pregnancy decreases the risk of preeclampsia. Nicotine, a major component of cigarettes, stimulates the efferent cholinergic anti-inflammatory pathway through peripherally expressed nicotinic acetylcholine receptors (nAChR) and is known to attenuate ischemia-reperfusion injury in kidney and liver. Prior studies indicated that complement activation was critical for placental ischemia-induced hypertension in a rat model. Thus, it was hypothesized here that nicotine was responsible for the protective effect of cigarette smoking in preeclampsia and would attenuate placental ischemia-induced systemic complement activation and hypertension. The Reduced Utero-placental Perfusion Pressure (RUPP) model in the pregnant rat was employed to induce placental ischemia, resulting in complement activation, fetal resorptions, and hypertension. On gestation day (GD)14, nicotine (1 mg/kg) or saline was administered via subcutaneous injection prior to RUPP surgery and daily through GD18. On GD19, placental ischemia significantly increased mean arterial pressure (MAP) in saline injected animals. However, the placental ischemia-induced increase in blood pressure was not evident in nicotine-treated animals and nicotine treatment significantly increased MAP variability. Circulating C3a was measured as an indicator of complement activation and increased C3a in RUPP compared to Sham persisted with nicotine treatment, as did fetal resorptions. These data suggested to us that nicotine may contribute to the decreased risk of preeclampsia with cigarette smoking, but this protective effect was confounded by additional effects of nicotine on the cardiovascular system.

Activation of the "Splenocardiac Axis" by electronic and tobacco cigarettes in otherwise healthy young adults

The "Splenocardiac Axis" describes an inflammatory signaling network underlying acute cardiac ischemia, characterized by sympathetic nerve stimulation of hematopoietic tissues, such as the bone marrow and spleen, which then release proinflammatory monocytes that populate atherosclerotic plaques, thereby promoting ischemic heart disease. Electronic (e) cigarettes, like tobacco cigarettes trigger sympathetic nerve activation, but virtually nothing is known about their influence on hematopoietic and vascular tissues and cardiovascular risks. The objective of this study was to determine if the Splenocardiac Axis is activated in young adults who habitually use either tobacco or e-cigarettes. In otherwise healthy humans who habitually use tobacco cigarettes or e-cigarettes (not both), we used ¹⁸F-flurorodeoxyglucose positron emission tomography/computer tomography (FDG-PET/CT) to test the hypothesis that tobacco or e-cigarettes increased metabolic activity of the hematopoietic and vascular tissues. FDG uptake in the spleen increased from nonuser controls (1.62 ± 0.07), to the e-cigarette users (1.73 ± 0.04), and was highest in tobacco cigarette smokers (1.82 ± 0.09; monotone P = 0.05). Similarly, FDG uptake in the aorta increased from the nonuser controls (1.87 ± 0.07) to the e-cigarette users (1.98 ± 0.07), and was highest in tobacco cigarette smokers (2.10 ± 0.07; monotone P = 0.04). FDG uptake in the skeletal muscle, which served as a control tissue, was not different between the groups. In conclusion, these findings are consistent with activation of the Splenocardiac Axis by emissions from tobacco cigarettes and e-cigarettes. This activation suggests a mechanism by which tobacco cigarettes, and potentially e-cigarettes, may lead to increased risk of future cardiovascular events.

Chronic nicotine exposure reduces klotho expression and triggers different renal and hemodynamic responses in klotho-haploinsufficient mice

The klotho gene, which encodes a single-pass transmembrane protein and a secreted protein, is expressed predominantly by the distal renal tubules and is related to calcium phosphorus metabolism, ion channel regulation, intracellular signaling pathways, and longevity. Klotho deficiency aggravates acute kidney injury and renal fibrosis. Exposure to nicotine also worsens kidney injury. Here, we investigated renal Klotho protein expression in a mouse model of chronic (28-day) nicotine exposure, in which mice received nicotine or vehicle (saccharine) in drinking water, comparing wild-type (WT) mice, klotho-haploinsufficient ( kl/+) mice, and their respective controls, in terms of the effects of that exposure. Nicotine exposure was associated with a significant decline in renal Klotho expression in WT and kl/+ mice as well as a reduction in the glomerular filtration rate in WT mice. Although plasma electrolytes were similar among the groups, fractional excretion of sodium was reduced in both nicotine-exposed groups. The nicotine-WT mice presented augmented baroreflex sensitivity to nitroprusside and augmented sympathetic cardiac modulation. However, nicotine- kl/+ mice presented higher plasma levels of urea and aldosterone together with a higher α-index (spontaneous baroreflex) and higher peripheral sympathetic modulation, as evaluated by spectral analysis. We can conclude that nicotine downregulates Klotho expression as well as that renal and autonomic responses to nicotine exposure are modified in kl/+ mice.

Use Behaviors, Dependence, and Nicotine Exposure Associated with Ad Libitum Cigar Smoking

Objectives

To examine factors important to cigar smoking and subsequent nicotine exposure, we evaluated the impact of cigar type, cigarette smoking history, and inhalation behaviors on nicotine dependence, smoking topography, and biomarkers of exposure in current exclusive cigar smokers.

Methods

Adult, exclusive cigar smokers (N = 77) were recruited based on cigar type, cigarette smoking history, and self-reported inhalation behaviors. Participants smoked their own brand product ad libitum for up to one hour; dependence symptoms, smoking topography, and biomarkers of exposure were assessed.

Results

Cigar smokers showed low levels of dependence. Cigar smoking alleviated withdrawal and craving symptoms, increased plasma nicotine concentration, and increased exhaled CO. Multiple regression analyses indicate that inhalation behaviors were associated with increased dependence and greater reductions in withdrawal symptoms upon cigar smoking. Large cigar smokers smoked longer and smoked more tobacco than small cigar and cigarillo smokers. Furthermore, large cigar smokers and self-reported inhalers were exposed to more nicotine than small cigar smokers and non-inhalers.

Conclusions

Our study suggests that cigar type and smoking behaviors affect dependence and nicotine exposure upon cigar smoking. These findings provide additional insight into the substantial risks associated with cigar smoking.

Cholinergic agonists reduce blood pressure in a mouse model of systemic lupus erythematosus

Increased inflammation arising from an abnormal immune response can damage healthy tissue and lead to disease progression. An important example of this is the accumulation of inflammatory mediators in the kidney, which can subsequently lead to hypertension and renal injury. The origin of this inflammation may involve neuro-immune interactions. For example, the novel vagus nerve-to-spleen mechanism known as the "cholinergic anti-inflammatory pathway" controls inflammation upon stimulation. However, if this pathway is dysfunctional, inflammation becomes less regulated and chronic inflammatory diseases such as hypertension may develop. Systemic lupus erythematosus (SLE) is an autoimmune disease with aberrant immune function, increased renal inflammation, and prevalent hypertension. We hypothesized that the cholinergic anti-inflammatory pathway is impaired in SLE and that stimulation of this pathway would protect from the progression of hypertension in SLE mice. Female SLE (NZBWF1) and control (NZW) mice were administered nicotine or vehicle for 7 days (2 mg/kg/day, subcutaneously) in order to stimulate the cholinergic anti-inflammatory pathway at the level of the splenic nicotinic acetylcholine receptor (α7-nAChR). Blood pressure was assessed posttreatment. Nicotine-treated SLE mice did not develop hypertension and this lower blood pressure (compared to saline-treated SLE mice) coincided with lower splenic and renal cortical expression of pro-inflammatory cytokines. These data provide evidence that the cholinergic anti-inflammatory pathway is impaired in SLE In addition, these data suggest that stimulation of the cholinergic anti-inflammatory pathway can protect the kidney by dampening inflammation and therefore prevent the progression of hypertension in the setting of SLE.

Nicotinic acetylcholine receptors in neuropathic and inflammatory pain

Nicotinic acetylcholine receptors (nAChRs) are actively being investigated as therapeutic targets for the treatment of pain and inflammation, but despite more than 30 years of research, there are currently no FDA-approved analgesics that are specific for these receptors. Much of the initial research effort focused on the α4β2 nAChR subtype, but more recently, additional subtypes have been identified as promising new leads and include α6β4, α7, and α9-containing nAChRs. This Review will focus on the distribution of these nAChRs in the cell types involved in neuropathic pain and inflammation and the activity of currently available nicotinic ligands.

Revisiting nicotine’s role in the ageing brain and cognitive impairment

Brain ageing is a complex process which in its pathologic form is associated with learning and memory dysfunction or cognitive impairment. During ageing, changes in cholinergic innervations and reduced acetylcholinergic tonus may trigger a series of molecular pathways participating in oxidative stress, excitotoxicity, amyloid-β toxicity, apoptosis, neuroinflammation, and perturb neurotrophic factors in the brain. Nicotine is an exogenous agonist of nicotinic acetylcholine receptors (nAChRs) and acts as a pharmacological chaperone in the regulation of nAChR expression, potentially intervening in age-related changes in diverse molecular pathways leading to pathology. Although nicotine has therapeutic potential, paradoxical effects have been reported, possibly due to its inverted U-shape dose-response effects or pharmacokinetic factors. Additionally, nicotine administration should result in optimum therapeutic effects without imparting abuse potential or toxicity. Overall, this review aims to compile the previous and most recent data on nicotine and its effects on cognition-related mechanisms and age-related cognitive impairment.

Spontaneous isolated dissection of the superior mesenteric artery and aneurysm formation resulting from segmental arterial mediolysis: a case report

Background

Spontaneous isolated dissection of the superior mesenteric artery (SMA) can lead to bowel ischemia, aneurysm rupture, or even death. Studies have suggested that mechanical or hemodynamic stress on the vascular wall of the SMA may be a contributor, but its pathogenesis is unclear.

Case presentation

A 57-year-old Japanese man with a history of untreated hypertension and hyperuricemia was admitted to our hospital with the sudden onset of severe epigastric pain. Laboratory findings showed elevated white blood cell count and C-reactive protein, and contrast-enhanced computed tomography (CT) of the abdomen demonstrated arterial dissection with luminal stenosis and aneurysm formation at the distal portion of the SMA after the branching of the jejunal artery, and intravenous nicardipine was administered. The patient’s epigastric pain resolved spontaneously but recurred on day 6 of his hospital stay. Contrast-enhanced abdominal CT revealed an enlarged aneurysm with wall thinning. Because of the risk of aneurysm rupture, the decision was made to perform aneurysmectomy and bowel resection on day 6. Histologic examinations revealed two separate dissecting lesions: one latent and the other resulting in aneurysm formation. Both lesions showed characteristics of segmental arterial mediolysis (SAM) with lack of arterial media, absence of internal and external elastic laminae and intimal proliferation.

Conclusions

Histologic findings in the present case suggest that mechanical or hemodynamic stress on the vascular wall and SAM-related vascular vulnerability may concomitantly contribute to the onset of isolated SMA dissection.

Electrophysiology-Based Assays to Detect Subtype-Selective Modulation of Human Nicotinic Acetylcholine Receptors

The Family Smoking Prevention and Tobacco Control Act of 2009 (Public Law 111-31) gave the US Food and Drug Administration (FDA) the responsibility for regulating tobacco products. Nicotine is the primary addictive component of tobacco and its effects can be modulated by additional ingredients in manufactured products. Nicotine acts by mimicking the neurotransmitter acetylcholine on neuronal nicotinic acetylcholine receptors (nAChRs), which function as ion channels in cholinergic modulation of neurotransmission. Subtypes within the family of neuronal nAChRs are defined by their α- and β-subunit composition. The subtype-selective profiles of tobacco constituents are largely unknown, but could be essential for understanding the physiological effects of tobacco products. In this report, we report the development and validation of electrophysiology-based high-throughput screens (e-HTS)for human nicotinic subtypes, α3β4, α3β4α5, α4β2, and α7 stably expressed in Chinese Hamster Ovary cells. Assessment of agonist sensitivity and acute desensitization gave results comparable to those obtained by conventional manual patch clamp electrophysiology assays. The potency of reference antagonists for inhibition of the receptor channels and selectivity of positive allosteric modulators also were very similar between e-HTS and conventional manual patch voltage clamp data. Further validation was obtained in pilot screening of a library of FDA-approved drugs that identified α7 subtype-selective positive allosteric modulation by novel compounds. These assays provide new tools for profiling of nicotinic receptor selectivity.

Sympathomimetic Effects of Acute E-Cigarette Use: Role of Nicotine and Non-Nicotine Constituents

BACKGROUND

Chronic electronic (e) cigarette users have increased resting cardiac sympathetic nerve activity and increased susceptibility to oxidative stress. The purpose of the present study is to determine the role of nicotine versus non-nicotine constituents in e-cigarette emissions in causing these pathologies in otherwise healthy humans.

METHODS AND RESULTS

Thirty-three healthy volunteers who were not current e-cigarette or tobacco cigarette smokers were studied. On different days, each participant used an e-cigarette with nicotine, an e-cigarette without nicotine, or a sham control. Cardiac sympathetic nerve activity was determined by heart rate variability, and susceptibility to oxidative stress was determined by plasma paraoxonase activity. Following exposure to the e-cigarette with nicotine, but not to the e-cigarette without nicotine or the sham control, there was a significant and marked shift in cardiac sympathovagal balance towards sympathetic predominance. The decrease in high-frequency component and the increases in the low-frequency component and the low-frequency to high-frequency ratio were significantly greater following exposure to the e-cigarette with nicotine compared with exposure to the e-cigarette without nicotine or to sham control. Oxidative stress, as estimated by plasma paraoxonase, did not increase following any of the 3 exposures.

CONCLUSIONS

The acute sympathomimetic effect of e-cigarettes is attributable to the inhaled nicotine, not to non-nicotine constituents in e-cigarette aerosol, recapitulating the same heart rate variability pattern associated with increased cardiac risk in multiple populations with and without known cardiac disease. Evidence of oxidative stress, as estimated by plasma paraoxonase activity, was not uncovered following acute e-cigarette exposure.

Smoking and risk of atrial fibrillation in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study

BACKGROUND

Whether smoking increases the risk of atrial fibrillation (AF) remains debatable due to inconsistent reports.

METHODS

We examined the association between smoking and incident AF in 11,047 participants from the REasons for Geographic And Racial Differences in Stroke (REGARDS) Study, one of the largest biracial, population-based cohort studies in the USA. Baseline (2003-2007) cigarette smoking status and amount (pack-years) were self-reported. Incident AF was determined by electrocardiography and history of a prior physician diagnosis at a follow-up examination conducted after a median of 10.6 years.

RESULTS

During follow-up, 954 incident AF cases were identified; 9.5% in smokers vs. 7.8% in non-smokers; p<0.001. In a model adjusted for socio-demographics, smoking (ever vs. never) was associated with a 15% increased risk of AF [OR (95%CI): 1.15(1.00, 1.31)], but this association was no longer significant after further adjustment for cardiovascular risk factors [OR (95% CI): 1.12 (0.97, 1.29)]. However, heterogeneities in the association were observed among subgroups; the association was stronger in young vs. old participants [OR (95%CI): 1.31 (1.03, 1.67) vs. 0.99 (0.83-1.18) respectively; interaction p-value=0.005] and in those with vs. without prior cardiovascular disease [OR (95%CI): 1.18 (0.90, 1.56) vs. 1.06 (0.90, 1.25) respectively; interaction p-value 0.0307]. Also, the association was significant in blacks but not in whites [OR (95%CI): 1.51 (1.12, 2.05) vs. 0.99 (0.84, 1.16), respectively], but the interaction p-value did not reach statistical significance (interaction p-value=0.65).

CONCLUSIONS

The association between smoking and AF is possibly mediated by a higher prevalence of cardiovascular risk factors in smokers, but there is marked heterogeneity in the strength of this association among subgroups which may explain the conflicting results in prior studies.

Causal Neuro-immune Relationships at Patients with Chronic Pyelonephritis and Cholecystitis. Correlations between Parameters EEG, HRV and White Blood Cell Count

We aim to analyze in bounds KJ Tracey's immunological homunculus conception the relationships between parameters of electroencephalogram (EEG) and heart rate variability (HRV), on the one hand, and the parameters of bhite blood cell count, on the other hand.

METHODS

In basal conditions in 23 men, patients with chronic pyelonephritis and cholecystitis in remission, recorded EEG ("NeuroCom Standard", KhAI Medica, Ukraine) and HRV ("Cardiolab+VSR", KhAI Medica, Ukraine). In portion of blood counted up white blood cell count.

RESULTS

Revealed that canonical correlation between constellation EEG and HRV parameters form with blood level of leukocytes 0.92 (p<10-5), with relative content in white blood cell count stubnuclear neutrophiles 0.93 (p<10-5), segmentonucleary neutrophiles 0.89 (p<10-3), eosinophiles 0.87 (p=0.003), lymphocytes 0.77 (p<10-3) and with monocytes 0.75 (p=0.003).

CONCLUSION

Parameters of white blood cell count significantly modulated by electrical activity some structures of central and autonomic nervous systems.

The Effects of Nicotine and Nicotine Abstinence on Stress-Induced Cardiovascular Reactivity

Abstract. The effects of 12 hr nicotine administration and abstinence on stress-induced cardiovascular reactivity were assessed within Light/Intermittent cigarette smokers and Habitual cigarette smokers. One hundred thirty-two male smokers (66 Habitual, 66 Light/Intermittent) were assigned to a Nicotine (21 mg) or Placebo patch condition. Cardiovascular reactivity was assessed during Baseline, a 6-min mental arithmetic task (Paced Auditory Serial Arithmetic Task) and a 5-min mirror-tracing task (Star Mirror Tracing Task). Within the Nicotine condition, Light/Intermittent smokers showed greater cardiac output (CO) increases, smaller stroke volume decreases, and smaller total peripheral resistance (TPR) increases than Light/Intermittent smokers in the Placebo condition. No condition differences in cardiovascular reactivity were demonstrated for Habitual smokers. Light/Intermittent smokers also showed greater CO increases than Habitual smokers during the mirror-tracing task but during the Nicotine condition only. During mental arithmetic, Light/Intermittent smokers had greater CO increases and smaller TPR increases than Habitual smokers across nicotine conditions. Habitual smokers responded to stress with increases in peripheral responses whereas Light/Intermittent smokers responded myocardially. Light/Intermittent smokers may have increased density of β-adrenergic receptors whereas Habitual smokers may have decreased density due to chronic smoking.

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.

A Randomised, Placebo-Controlled, Crossover Study Investigating the Effects of Nicotine Gum on Strength, Power and Anaerobic Performance in Nicotine-Naïve, Active Males

Background

Nicotine use amongst athletes is high and increasing, especially team sports, yet the limited previous studies investigating the performance consequences of this behaviour have not examined the effects of the principal active ingredient, nicotine, per se. Therefore, we determined whether nicotine gum affected muscular and anaerobic performance.

Methods

Nine active males (24 ± 3 years) completed three trials in a random order in which 20 min prior to testing they chewed 2 mg (NIC-2), 4 mg (NIC-4) nicotine or flavour-matched placebo (PLA) gum. Peak and average peak isometric, concentric and eccentric leg extensor torque was measured followed by vertical counter-movement jump height and a 30-s Wingate test. Heart rate was measured whilst capillary blood samples determined pH, HCO₃⁻ and venous blood confirmed the presence of nicotine.

Results

Nicotine was confirmed by the presence of its major metabolite, cotinine and participants reported no side effects with nicotine. Peak and average peak isometric and eccentric torque was significantly affected (NIC-2 > PLA; p < 0.05) whilst peak (NIC-2 > PLA; p < 0.05) but not average peak (p > 0.05) concentric torque was different between trials. Counter-movement jump height was similar across trials (p > 0.05). Anaerobic capacity during the Wingate remained similar across trials (p > 0.05); however, pacing strategy (peak power and rate of fatigue) was different during NIC-2 than PLA. pH was affected by nicotine (NIC-2 > PLA; p < 0.05) and was reduced following the Wingate in all trials. HCO₃⁻ showed similar responses across trials (p > 0.05) although it was also reduced following the Wingate (p < 0.05), whilst heart rate was significantly affected (NIC-2/NIC-4 > PLA; p < 0.05).

Conclusions

Chewing low-dose (2 mg) nicotine gum 20 min prior to exercise significantly improved leg extensor torque but did not affect counter-movement jump height or Wingate performance compared to a placebo, whilst there were minimal effects of the 4 mg nicotine gum on the performance parameters measured.

The Association of Cigarette Smoking With High-Frequency Heart Rate Variability: An Ecological Momentary Assessment Study

OBJECTIVE

Evidence from both laboratory and observational studies suggests that acute and chronic smoking leads to reduced high-frequency heart rate variability (HF-HRV), a measure of cardiac vagal regulation. We used ecological momentary assessment (EMA) to study the effect of smoking on concurrent HF-HRV in a trial measuring the effects of hostility reduction and compared 24-hour HF-HRV in smokers and nonsmokers.

METHOD

Ambulatory electrocardiogram data were collected before randomization from 149 healthy individuals with high hostility levels (20-45 years, body mass index ≤ 32 kg/m) and paired with concurrent EMA ratings of smoking and physical position during waking hours. A multilevel mixed model was estimated associating ln(HF-HRV) from smoking status (between-person factor) and person-centered momentary smoking (within-person factor, treated as a random effect), adjusting for momentary physical position, medication use, and consumption of alcohol and caffeine.

RESULTS

Thirty-five smokers and 114 nonsmokers provided both EMA and HF-HRV data. Within smokers, ln HF-HRV was reduced by 0.31 millisecond (p = .04) when participants reported having recently smoked cigarettes, compared with when they had not. The 24-hour HF-HRV was significantly lower in smokers (M [SD] = 5.24 [0.14] milliseconds) than nonsmokers (5.63 ± 0.07 milliseconds, p = .01).

CONCLUSIONS

In healthy smokers with high hostility levels used as their own controls during daily living, smoking acutely reduced HF-HRV. HF-HRV was also reduced in smokers as compared with nonsmokers. Although limited by a small sample of individuals with high hostility levels, these findings nonetheless provide additional evidence that cardiac vagal regulation is lowered by cigarette smoking, which may be one of the numerous pathophysiological effects of smoking.

Influences of lifestyle factors on cardiac autonomic nervous system activity over time

Physical activity, alcohol use and smoking might affect cardiovascular disease through modifying autonomic nervous system (ANS) activity. We investigated: 1) whether there are consistent relationships between lifestyle factors and cardiac ANS activity over time, and 2) whether 2-year changes in lifestyle factors relate to 2-year changes in cardiac activity. Baseline (n=2618) and 2-year follow-up (n=2010) data of the Netherlands Study of Depression and Anxiety was combined. Baseline data was collected in the Netherlands from 2004-2007. Lifestyle factors were habitual physical activity, frequency of sport activities, alcohol use, and smoking. Indicators of cardiac activity were heart rate (HR), respiratory sinus arrhythmia (RSA) and pre-ejection period (PEP) (100min of registration). The results showed that high physical activity (-1.8beats/min compared to low activity), high frequency of sport activities ('couple of times/week': -2.5beats/min compared to 'almost never') and mild/moderate alcohol use (-1.2beats/min compared to non-drinking) were related to low HR. Heavy smoking was related to high HR (>30cigarettes/day: +5.1beats/min compared to non-smoking). High frequency of sport activities was associated with high RSA ('couple of times/week':+1.7ms compared to 'almost never') and moderate smoking with longer PEP (11-20cigarettes/day: +2.8ms compared to non-smoking). Associations were consistent across waves. Furthermore, 2-year change in frequency of sport activities and number of smoked cigarettes/day was accompanied by 2-year change in HR (β=-0.076 and β=0.101, respectively) and RSA (β=0.046 and β=-0.040, respectively). Our findings support consistent effects of lifestyle on HR and parasympathetic activity in the expected direction. Cardiac autonomic dysregulation may be partly mediating the relationship between lifestyle and subsequent cardiovascular health.

M-currents (Kv7.2-7.3/KCNQ2-KCNQ3) Are Responsible for Dysfunctional Autonomic Control in Hypertensive Rats

Autonomic dysfunctions play important roles in hypertension, heart failure and arrhythmia, often with a detrimental and fatal effect. The present study analyzed if these dysfunctions involved M-channels (members of the Kv7/KNCQ family) in spontaneously hypertensive rats (SHR). Cardiac output and heart rate (HR) were recorded by a flow probe on the ascending aorta in anesthetized SHR and normotensive rats (WKY), and blood pressure (BP) by a femoral artery catheter. Total peripheral vascular resistance (TPR) was calculated. XE-991 (Kv7.1-7.4-inhibitor) reduced resting HR in WKY but only after reserpine in SHR. XE-991 increased TPR and BP baseline in both strains. Retigabine (Kv7.2-7.5-opener) reduced HR, TPR and BP, also after reserpine. Depolarization induced by 3,4-diaminopyridine (3,4-DAP), a voltage-sensitive K⁺ channel (Kv) inhibitor, activated release of both acetylcholine and norepinephrine, thus activating an initial, cholinergic bradycardia in SHR, followed by sustained, norepinephrine-dependant tachycardia in both strains. XE-991 augmented the initial 3,4-DAP-induced bradycardia and eliminated the late tachycardia in SHR, but not in WKY. The increased bradycardia was eliminated by hexamethonium and methoctramine (M2muscarinic receptor antagonist) but not reserpine. Retigabine eliminated the increased bradycardia observed in reserpinized SHR. XE-991 also increased 3,4-DAP-stimulated catecholamine release, but not after hexamethonium or reserpine. Conclusions: M-currents hampered parasympathetic ganglion excitation and, through that, vagal control of HR, in SHR but not WKY. M-currents also opposed catecholamine release in SHR but not in WKY. M-currents represented a vasodilatory component in resting TPR-control, with no strain-related difference detected. Excessive M-currents may represent the underlying cause of autonomic dysfunctions in hypertension.

Traditional Cardiovascular Risk Factors for Incident Atrial Fibrillation

To prevent atrial fibrillation (AF), it is essential to reduce its risk factors and extend healthy life expectancy as a result. There are few reviews on the AF risk factors. We discuss them and approach the prevention of AF. We briefly review traditional risk factors for incident AF, especially focusing on high blood pressure, overweight/obesity, dyslipidemia, diabetes, tobacco smoking, and excessive drinking. When trying to prevent AF by modifying lifestyle, it is important to comprehensively utilize the risk factors for AF to predict the 10-year as an AF risk score. However, there are only 2 risk scores of AF just for the US population. There are few studies of the AF risk factors in non-Western populations. A risk score for incident AF in non-Westerners is awaited because different race and lifestyles may have different contributions as AF risk factors. An AF risk score in accordance with race could be useful for identifying persons with a high risk of AF in order to encourage them to consult a doctor and encourage lifestyle modifications before the onset of AF. (Circ J 2016; 80: 2415-2422).

Nicotine Mediates CD161a+ Renal Macrophage Infiltration and Premature Hypertension in the Spontaneously Hypertensive Rat

RATIONALE

Renal inflammation contributes to the pathophysiology of hypertension. CD161a+ immune cells are dominant in the (SHR) spontaneously hypertensive rat and expand in response to nicotinic cholinergic activation.

OBJECTIVE

We aimed to phenotype CD161a+ immune cells in prehypertensive SHR after cholinergic activation with nicotine and determine if these cells are involved in renal inflammation and the development of hypertension.

METHODS AND RESULTS

Studies used young SHR and WKY (Wistar-Kyoto) rats. Splenocytes and bone marrow cells were exposed to nicotine ex vivo, and nicotine was infused in vivo. Blood pressures, kidney, serum, and urine were obtained. Flow cytometry, Luminex/ELISA, immunohistochemistry, confocal microscopy, and Western blot were used. Nicotinic cholinergic activation induced proliferation of CD161a+/CD68+ macrophages in SHR-derived splenocytes, their renal infiltration, and premature hypertension in SHR. These changes were associated with increased renal expression of MCP-1 (monocyte chemoattractant protein-1) and VLA-4 (very-late antigen-4). LLT1 (lectin-like transcript 1), the ligand for CD161a, was overexpressed in SHR kidney, whereas vascular cellular and intracellular adhesion molecules were similar to those in WKY. Inflammatory cytokines were elevated in SHR kidney and urine after nicotine infusion. Nicotine-mediated renal macrophage infiltration/inflammation was enhanced in denervated kidneys, not explained by angiotensin II levels or expression of angiotensin type-1/2 receptors. Moreover, expression of the anti-inflammatory α7-nAChR (α7-nicotinic acetylcholine receptor) was similar in young SHR and WKY rats.

CONCLUSIONS

A novel, inherited nicotinic cholinergic inflammatory effect exists in young SHR, measured by expansion of CD161a+/CD68+ macrophages. This leads to renal inflammation and premature hypertension, which may be partially explained by increased renal expression of LLT-1, MCP-1, and VLA-4.

Echocardiographic consequences of smoking status in middle-aged subjects

BACKGROUND

Smoking is known to have many short- and long-term cardiovascular effects. Cardiac index (CI), which is cardiac output indexed to body surface area, is considered to be a valid measure of cardiac performance. We investigated whether there were any differences in CI or other echocardiographic variables between never smokers, ex-smokers, and current smokers in a cardiopulmonary healthy population.

METHODS

Subjects (n=355) from a previous population-based respiratory questionnaire survey (never smokers, ex-smokers, and current smokers without significant chronic obstructive lung disease) were examined with echocardiography, and CI (L/min/m² ) was calculated.

RESULTS

Current smokers had a higher CI than never smokers 2.61±0.52 L/min/m² vs. 2.42±0.49 L/min/m² (P<.01). Ex-smokers had a nonsignificant, numerically higher value for CI than never smokers 2.54±0.54 L/min/m² vs. 2.42±0.49 L/min/m² (P>.05). Smoking status had no significant effect on other echocardiographic variables.

CONCLUSION

We conclude that currents smokers without known cardiac disease or significant chronic obstructive lung disease show signs of slightly altered hemodynamics.

Long-term potentiation in autonomic ganglia: Potential role in cardiovascular disorders

Ganglionic long-term potentiation (gLTP) is an activity-dependent, enduring enhancement of ganglionic transmission. This phenomenon may be induced in autonomic ganglia of an organism under certain conditions where repetitive impulses surge from the central nervous system (CNS) to the periphery. Chronic stress, repetitive epileptic seizure or chronic use of CNS stimulants could induce gLTP, which would result in a long lasting heightening of sympathetic tone to the cardiovascular system causing hypertension and disturbed cardiac rhythm that may lead to sudden cardiac death. These conditions are briefly reviewed in this article.