Thèse (Ph. D.)--Université Laval, 2009. / Bibliogr.: f. 157-172. Publié aussi en version électronique dans la Collection Mémoires et thèses électroniques.

Cigarette smoking (CS) represents the main causative agent underlying development and progress of COPD. Recently, involvement of CS in the pathogenesis of COPDassociated muscle abnormalities is becoming increasingly evident. Nevertheless, involved triggers and underlying mechanisms remain largely unknown. This study was conceived in order to examine effects of cigarette smoke exposure on skeletal muscle morphology, vascular supply and function. For this purpose, we have specifically designed murine COPD/emphysema model and gastrocnemius muscle was examined, while in vitro experiments were conducted using murine C2C12 skeletal muscle myocytes. In addition to the mild emphysematous changes present in the lungs of CS-exposed mice, our results demonstrated evident signs of muscle atrophy reflected by decreased fiber cross-sectional area, profound fiber size variation and reduced body mass. Furthermore, we have observed impairment in terminal myogenesis and lower number of myonuclei in skeletal muscles of CS-exposed animals despite evident activation of muscle repair process. Additionally, our results demonstrate capillary rarefaction in skeletal muscles of CS-exposed animals which was associated with deregulation of hypoxia-angiogenesis signaling, reduced levels of angiogenic factors such as HIF1-α and VEGF and enhanced expression of VHL and its partner proteins PHD2 and Ube2D1. The results of our in-vitro experiments demonstrated that VHL and its ubiquitination machinery can be synergistically regulated by TNF and hypoxia consequentially impairing angiogenic potential of skeletal muscle myocytes. Finally, we have shown that CS elicits chronic ER stress in murine skeletal muscles which is associated with activation of ERAD and apoptotic pathways as mirrored by elevated expression of Usp19, caspase 12 and caspase 3 in skeletal muscles of CSexposed animals. Moreover, molecular and morphological alterations in CS-exposed mice resulted in impairment of muscle function as reflected by their impaired exercise capacity. Taken together, from our results it is evident that cigarette smoke exposure elicits set of morphological, vascular and functional changes highly resembling those observed in COPD. Additionally, CS induces wide range of molecular alterations and signaling pathway deregulations suggesting profound effects of cigarette smoke exposure on skeletal muscle cell homeostasis.

Background: Smoking continues to be the leading cause of preventable disease, disability and death in the United States attributing to more than 480,000 deaths every year. An estimated 36.5 million US adults (15% of US population) currently smoke, and more than 16 million live with a smoking-related disease. Since recent years, there has been a surge of alternate tobacco products in the US markets, and one such product that has gained importance was electronic cigarettes. Studies have demonstrated a rapid increase in e-cigarette use among US adults. However, research is limited on the effects of e-cigarette on human health. Thus, using a nationally representative sample of US adults, we investigated the association of e-cigarette use with coronary heart disease (CHD) among adults aged ≥18-years in the US. Methods: Data from the 2016 Behavioral Risk Factor Surveillance System (BRFSS) were used to conduct this study. BRFSS is a cross-sectional survey administered to 486,303 adults in all 50 states to collect information about their health-related risk behaviors, chronic health conditions and the use of preventive services. Participants’ self-reported responses were used to define study outcome (CHD), exposure (current e-cigarette use) and covariates (demographics [sex and race], behaviors [cigarette smoking, alcohol consumption, marijuana use, physical activity], and physical conditions [overweight or obesity]). Multiple logistic regression analysis was conducted to determine the association between e-cigarette use and CHD. Adjusted odds ratio and corresponding 95% confidence intervals were presented. Results: Approximately 6.19% of US adults reported CHD events and 3.1% of US adults were current e-cigarette users. Approximately 5.42% of e-cigarette smoking US adults reported CHD outcomes in 2016. Overall, the odds of CHD events was 34.9% less among e-cigarette users than those who were not e-cigarette users (adjusted odds ratio (aOR): 0.65, 95% confidence interval (CI): 0.60-0.70, p Conclusion: The study found out that e-cigarette user was less likely associated with CHD outcomes in US adults. Given the limitations of cross-sectional study nature and self-reported bias of responses, longitudinal studies with objective measures are needed to further investigate the association between e-cigarette use and CHD.

Electronic Nicotine Delivery Systems (ENDS) are methods of delivering nicotine without combustion, which happens in cigarettes. These devices consist of a heating element, a battery, and a tank which stores eliquid. Over the years these devices have become more powerful, and capable of increased delivery of nicotine. There is a large variety of flavors and devices, which causes trouble for standardized studies. These devices were created to help cigarette users quit smoking; however, they are associated with significant dual use. ENDS produce lower levels of most toxic chemicals when compared to cigarettes, and significantly increased levels when compared to not smoking. Newer generation ENDS have capabilities of producing levels of reactive oxygen species and carbonyl compounds at levels similar to cigarettes. ENDS use has detrimental effects on the genome, immune system, and lung function due to exposure from these chemicals. These effects are at lower levels when compared to cigarette use. Chronic ENDS use has been associated with chronic obstructive pulmonary disorder (COPD), with an even higher association with dual use. ENDS use also causes DNA adduct formation, and activates protein kinases, nicotine acetylcholine receptors and other pathways for lung cancer as cigarette use. The full health effects of ENDS use are still unknown, from the currents studies it is clear that its use is not without harm.

There has been a well-documented and causal relationship between cigarette smoking and disease for over forty years, and at least an implicit concern over tobacco and health for decades, if not centuries prior; however, government policy on how to address tobacco as a public health issue has been erratic. At the turn of the twentieth century, when cigarettes first became a national phenomenon, the federal government imposed few if any regulations, and even encouraged the use of cigarettes. By the 1960s, government, public health entities and the tobacco industry were cooperating to try to fix the problem. Although there was great success in this early, if uneasy alliance, by the 1980s this coalition was fragmented and the search for a pragmatic solution to the tobacco problem came to an abrupt end. This dissertation is an investigation into how policy-makers, tobacco industry executives and public health officials each ignored opportunities to come to a practical solution to the problem which confronted them. The 1960s saw these groups work together to formulate a harm reduction policy approach which would lessen, if not eliminate, the concerns from each constituent group. Despite some significant early successes, this effort was derailed due to partisan positioning, misguided self-interest, and certain individual personalities. This analysis of the safer-cigarette campaign sheds light on a little explored avenue in the tobacco debate, as well as highlights the challenges of policy making in Washington.

Streptococcus pneumoniae is a common human pathogen, causing severe and often life-threatening respiratory tract infections. Even though most patients receive appropriate antimicrobial chemotherapy, a significant percentage still die. Cigarette smoking is a well-documented risk factor for severe pneumococcal pneumonia; however, the microbiological/ immunological mechanisms which predispose smokers to infection are not yet completely understood. The pneumococcal toxin, pneumolysin, is a major virulence factor of S. pneumoniae; it forms pores in eukaryotic cell membranes, resulting in the influx of extracellular Ca2+. Biofilm is a self-generated polymer matrix, used by microbial pathogens to isolate themselves from both host defences, as well as antibiotics. In this dissertation, the effects of cigarette smoke condensate (CSC) on the bioactivity of pneumolysin, as well as on the growth of, and production of biofilm by Streptococcus pneumoniae are described. A clinical isolate of S. pneumoniae, strain 172, was used for both growth and biofilm determinations in the presence or absence of concentrations of CSC (20-160 μg/ml), representative of the smoking habit. Growth and biofilm determinations were performed using spectrophotometric procedures, viability by standard colony forming unit procedures, and the effect of the condensate on pneumolysin bioactivity using a fura-2/AM-based spectrofluorometric procedure. Exposure of the pneumococcus to CSC resulted in a dose-dependent increase in biofilm formation which achieved statistical significance (P≤0.05) at concentrations of 80 and 160 μg/ml, in the setting of modest effects on bacterial growth. These findings were not unique to S. pneumoniae since exposure of Staphylococcus aureus, a known biofilm former, to CSC showed similar results. Exposure of pneumolysin to CSC (20 and 40 μg/ml) was accompanied by attenuation of the biological activity of the toxin, resulting in impaired pore-forming ability manifest as a considerable reduction in influx of extracellular Ca2+ following exposure of isolated neutrophils to the toxin. It is possible that CSC acts as a stressor to the bacteria, thereby enhancing biofilm formation and consequently persistence in the respiratory tract. These effects of the toxin may be complemented by inactivation of pneumolysin, presumably by pro-oxidative mechanisms, affecting innate cellular host defences. These mechanisms may underpin the predisposition of smokers to develop severe pneumococcal infections. / AFRIKAANS : Streptococcus pneumoniae is ‘n algemene menslike patogeen, wat ernstige en soms lewensbedreigende lugweg infeksies veroorsaak. Alhoewel die meeste pasiënte geskikte antimikrobiese chemoterapie ontvang, sterf ‘n betekenisvolle hoeveelheid steeds. Sigaretrook is ‘n welbekende risikofaktor vir ernstige pneumokokkale pneumonie; die mikrobiologiese/ immunologiese meganisme wat rokers vatbaar maak vir infeksie word egter nog nie heeltemal verstaan nie. Die pneumokokkale toksien, pneumolisien, is ‘n belangrike virulensie faktor van S. pneumoniae; dit vorm porieë in die eukariotiese selmembrane wat ‘n invloei van ekstrasellulêre Ca2+ tot gevolg het. Biofilm is ‘n self-genererende polimeermatriks, wat deur mikrobiese patogene gebruik word om hulself teen gasheerverdedigings meganismes en antibiotika te isoleer. In hierdie verhandeling word die uitwerking van sigaretrook kondensaat (SRK) op die bioaktiwiteit van pneumolisien, asook die effekte op groei en die produksie van biofilm deur S. pneumoniae, beskryf. ‘n Kliniese isolaat van S. pneumoniae, stam 172, is gebruik vir beide groei en biofilm bepalings, in die teenwoordigheid en afwesigheid van SRK (20-160 μg/ml), wat verteenwoordigend van die rook gewoonte is. Groei en biofilm bepalings is uitgevoer deur gebruik te maak van spektrofotometriese prosedures, lewensvatbaarheid, deur standard kolonievormende eenheid prosedures, en die effek van die kondensaat op die pneumolisien bioaktiwiteit, deur fura-2/AM-gebaseerde spektrofluorometriese prosedures. Blootstelling van die pneumokokkus aan SRK het in ‘n dosis-verwante verhoging in biofilm-formasie tot gevolg gehad, wat statistiese betekenisvolheid (P≤0.05) bereik het teen konsentrasies van 80 en 160 μg/ml, teenoor die agtergrond van beskeie effekte op bakteriële groei. Hierdie bevindinge is nie uniek aan S. pneumoniae nie, aangesien blootstelling van Staphylococcus aureus, ‘n bekende biofilm-vormer, aan SRK soortgelyke resultate gelewer het. Blootstelling van pneumolisien aan SRK (20-160 μg/ml) was geassosieer met die verswakking van die biologiese aktiwiteit van die toksien, met verminderde porie-vormende vermoë, wat gemanifesteer het met ‘n ongelooflike verlaging in die invloei van ekstrasellulêre Ca2+ na die blootstelling van geïsoleerde neutrofiele aan die toksien. Dit is moontlik dat die SRK as ‘n stressor vir die bakterieë optree, en daardeur biofilm formasie en gevolglik hardnekkige infeksies in die lugweg tot sellulêre gasheervededing beïnvloed. Hierdie effekte op die toksien mag gekomplimenteer word deur die inaktivering van pneumolisien, heelwaarskynlik deur pro-oksidatiewe meganismes, wat die vatbaarheid van rokers om ernstige pneumokokkale infeksies te ontwikkel, beklemtoon. / Dissertation (MSc)--University of Pretoria, 2011. / Immunology / Unrestricted

Prior studies indicate a link between poor academic performance and e-cigarette use in high school students (18 years and below). However, the effect of post high school education on e-cigarette use is poorly summarized in literature. The objective of the current study was to determine if there was a difference in prevalence of past 30-day e-cigarette use in a national sample of young adults due to different educational levels. Four groups of young adults were studied based on their level of education: High School Dropouts, High School Graduates/GED, Current College Students, and College Graduates. Data from the Population Assessment of Tobacco and Health (PATH) study was used to assess the association between educational attainment and e-cigarette use in young adults (ages 18-24). Relative e-cigarette use was measured via a survey, along with other control variables, across the four groups. Common factors affecting use across each educational attainment group were also analyzed. It was found that e-cigarette use tended to decrease as educational attainment increased among young adults. That is, higher levels of education seemed to be a protective factor against e-cigarette use when controlled for other factors. This study expands past research on this topic to include young adults as they transition from adolescents to adults. Prior studies established a link between academic performance at the same educational level (high school). This study indicates a difference in e-cigarette use between different educational levels. This study also differentiates between e-cigarette use among High School Dropouts and High School Graduates/GED.

Rationale. Cigarette smoking is a well-known risk factor for cardiovascular disease, including arterial diseases such as atherosclerosis and abdominal aortic aneurysm. However, our understanding of how exposure to cigarette smoke impacts arterial disease pathogenesis is not well known. Consequently, this doctoral thesis focuses on understanding the development of atherosclerosis and aortic aneurysm in the context of exposure to cigarette smoke. In particular, since monocytes and macrophage are key immune cells implicated in arterial pathology, this work concentrates on understanding the impact of cigarette smoke exposure on the function and kinetics of monocytes and arterial macrophages. Main Findings. Using a mouse model that combines two clinically relevant risk factors, hyperlipidemia and cigarette smoke, we showed that smoke exposure increases atherosclerosis and induces the spontaneous formation, progression, and rupture of abdominal aneurysms. We also provide experimental evidence that atherosclerosis strongly associates with regions of elastin damage and arterial dilation, suggesting atherogenesis may directly contribute to abdominal aneurysm formation. Given the importance of macrophages in arterial disease, we investigated arterial macrophage heterogeneity and function following exposure to cigarette smoke. We report that cigarette smoke exposure increased the abundance of arterial monocytes and macrophages, whereas heterogeneity was primarily driven by hypercholesterolemia in aneurysmal tissue. Specifically, hypercholesterolemia is associated with an increase in macrophage populations with putative functions in inflammation and tissue remodelling including Trem2 foamy macrophages, inflammatory macrophages, and interferon-inducible macrophages. Moreover, we demonstrated that arterial macrophages play a critical role in elastin fragmentation within the arterial wall of smoke exposed mice. Finally, we investigated the impact of cigarette smoke on kinetic factors that can contribute to arterial macrophage accumulation. We found that, despite increased development of arterial disease, exposure to cigarette smoke is associated with an overall suppression of circulating monocytes and pro-inflammatory cytokines. Using a parabiosis model, we show monocyte recruitment is significantly increased and is likely a key factor contributing to accumulation of arterial macrophages following exposure to cigarette smoke. We also present evidence suggesting that endothelial dysfunction, related to a loss of endothelial nitric oxide synthase, contributes to increased arterial monocyte recruitment following exposure to cigarette smoke. Conclusions and Significance. Overall, we provide evidence that atherosclerosis likely contributes to abdominal aneurysm pathology in a model of cigarette smoke-induced aneurysm formation. We further provide insight into how tobacco smoke promotes arterial disease development through increased local accumulation of arterial macrophages despite suppressed monopoiesis and systemic inflammation. We identify monocyte recruitment and endothelial dysfunction as key factors contributing to the increased accumulation of arterial macrophages, with no overall differences in macrophage heterogeneity, following smoke exposure. In addition to providing insight into the increased risk of arterial disease following exposure to cigarette smoke, this study also provides experimental evidence that atherogenesis can contribute to abdominal aneurysm pathology. Overall, this thesis furthers our understanding of arterial disease pathogenesis and can provide a foundation for further mechanistic or therapeutic focused research aimed at reducing the burden of cardiovascular disease. / Thesis / Doctor of Philosophy (PhD) / Diseases that affect the heart and major blood vessels are one of the leading causes of illness and death worldwide. Atherosclerosis is one such disease caused by the buildup of fatty deposits in the walls of major blood vessels called arteries. This buildup can eventually block the artery and lead to a heart attack or stroke. Abdominal aortic aneurysms are another type of disease that affects arteries. In this case, the walls of the artery grow weak and begin to balloon out until the artery eventually breaks causing severe internal bleeding and death. One of the most important cells involved in the development of atherosclerosis and aneurysms is the macrophage, a type of white blood cell that is an important part of the immune system and found in diseased arteries. Although we know that cigarette smoking is one of the most significant risk factors for developing atherosclerosis and abdominal aneurysms, we do not fully understand why. Therefore, the goal of this thesis project was to investigate how cigarette smoke affects the development of arterial disease with a focus on understanding how it impacts the movement and function of macrophages. Using a mouse model, we found that the development of atherosclerosis and aneurysm are likely related, and also identified ways that exposure to cigarette smoke increases the numbers of macrophages in arteries. This work advances our understanding of how arterial diseases may be related and provides insight into how smoking can increase the risk of developing arterial disease.

Chronic obstructive pulmonary disease (COPD) is a leading cause of global morbidity and mortality, with the potential to afflict as many as half of the 1.1 billion smokers in the world. The inflammatory response to cigarette smoke is believed to mediate the progressive and irreversible loss of lung function that characterizes COPD. The greatest burden of the disease arises from episodes of worsened symptoms and inflammation, usually triggered by microbial infection. Currently, the mechanisms that drive cigarette smoke-induced inflammation are being elucidated but ambiguity remains about this response and the inflammatory response engaged in a smoke-exposed lung experiencing a microbial infection. This thesis sought to investigate inflammatory mediators induced by cigarette smoke and those induced by bacteria, the most common cause of infectious exacerbations of COPD, in the context of smoke exposure. In chapter two we investigated the role of Breast Regression Protein-39 (BRP-39), a gene commonly observed to be increased under inflammatory conditions, in the inflammatory response to cigarette smoke. In order to determine the mechanisms of BRP-39 induction, its expression and inflammation was assessed in IL-13, IL-18, and IL-1R1 deficient mice. BRP-39 was found to be redundant in cigarette smoke-induced inflammation, but these data confirmed that IL-1R1 was a crucial mediator of this response. After examining the inflammatory response elicited by smoke alone, we investigated the importance of IL-1 signaling in a model of bacterial exacerbation of cigarette smoke-induced inflammation. We found that the exacerbated neutrophilia that typifies the response of a smoke-exposed lung to bacteria was dependent on IL-1α-mediated production of the CXCR2 ligand CXCL5. This study identified the unique phenomenon that cigarette smoke primes alveolar macrophages to produce excessive amounts of IL-1α in response to bacterial stimuli. The purpose of the final study of the thesis was to more comprehensively characterize the extent to which cigarette smoke changes the phenotype of macrophages. Examining total gene expression by microarray found that smoke-exposed alveolar macrophages were in a proliferative state expressing a unique profile of inflammatory mediators. Further analysis revealed that this was likely the result of a pulmonary environment rich in growth factors. Taken together, these data provide detail to the understanding of the biological process of inflammation that drives the pathogenesis of COPD. These studies identify a phenomenon that predisposes smokers to experience more severe responses to bacteria and reinforces the targeting of IL-1 signaling in the treatment of COPD. / Thesis / Doctor of Philosophy (Medical Science)

Twenty-one 8-14 kg adult male stumptailed macaques, Macaca arctoides, were fed a standard laboratory diet and divided into 3 groups. The high-dose group and low-dose group were exposed to cigarette smoke at the human equivalent of 3 packs and 1 pack per day, respectively, 7 days per week, for 3-5 years. Eight animals served as cage and sham controls. Peak blood carboxyhemoglobin (COHb) levels measured immediately after smoking showed levels of 0.5 ± 0.1%, 3.6 ± 1.0%, and 5.7 ± 2.8% for. sham controls, low, and high dose smokers, respectively. Hemoglobin and hematocrit values were 2-7% higher (N.S. to P < 0.05) for smoking groups, presumably as a consequence of chronically elevated COHb levels. No significant differences were seen in total plasma cholesterol and lipoprotein cholesterol concentration measured at four intervals over a period of one year. We conclude from these data that, while fed a low fat diet, chronic cigarette smoke inhalation fails to alter plasma lipoprotein levels in this animal model.