Th17/Treg Imbalance in Chronic Obstructive Pulmonary Disease: Clinical and Experimental Evidence.

The imbalance between pro- and anti-inflammatory immune responses mediated by Th17 and Treg cells is deeply involved in the development and progression of inflammation in chronic obstructive pulmonary disease (COPD). Several clinical and experimental studies have described the Th17/Treg imbalance in COPD progression. Due to its importance, many studies have also evaluated the effect of different treatments targeting Th17/Treg cells. However, discrepant results have been observed among different lung compartments, different COPD stages or local and systemic markers. Thus, the data must be carefully examined. In this context, this review explores and summarizes the recent outcomes of Th17/Treg imbalance in COPD development and progression in clinical, experimental and in vitro studies.

Th17/Treg-Related Intracellular Signaling in Patients with Chronic Obstructive Pulmonary Disease: Comparison between Local and Systemic Responses.

Th17/Treg imbalance plays a pivotal role in COPD development and progression. We aimed to assess Th17/Treg-related intracellular signaling at different COPD stages in local and systemic responses. Lung tissue and/or peripheral blood samples were collected and divided into non-obstructed (NOS), COPD stages I and II, and COPD stages III and IV groups. Gene expression of STAT3 and -5, RORγt, Foxp3, interleukin (IL)-6, -17, -10, and TGF-ß was assessed by RT-qPCR. IL-6, -17, -10, and TGF-ß levels were determined by ELISA. We observed increased STAT3, RORγt, Foxp3, IL-6, and TGF-ß gene expression and IL-6 levels in the lungs of COPD I and II patients compared to those of NOS patients. Regarding the systemic response, we observed increased STAT3, RORγt, IL-6, and TGF-ß gene expression in the COPD III and IV group and increased IL-6 levels in the COPD I and II group. STAT5 was increased in COPD III and IV patients, although there was a decrease in Foxp3 expression and IL-10 levels in the COPD I and II and COPD III and IV groups, respectively. We demonstrated that an increase in Th17 intracellular signaling in the lungs precedes this increase in the systemic response, whereas Treg intracellular signaling varies between the compartments analyzed in different COPD stages.

Th17/Treg imbalance in COPD development: suppressors of cytokine signaling and signal transducers and activators of transcription proteins.

Th17/Treg imbalance contributes to chronic obstructive pulmonary disease (COPD) development and progression. However, intracellular signaling by suppressor of cytokine signaling (SOCS) 1 and SOCS3 and the proteins signal transducer and activator of transcription (STAT) 3 and STAT5 that orchestrate these imbalances are currently poorly understood. Thus, these proteins were investigated in C57BL/6 mice after exposure to cigarette smoke (CS) for 3 and 6 months. The expression of interleukin was measured by ELISA and the density of positive cells in peribronchovascular areas was quantified by immunohistochemistry. We showed that exposure to CS in the 3rd month first induced decreases in the numbers of STAT5+ and pSTAT5+ cells and the expression levels of TGF-ß and IL-10. The increases in the numbers of STAT3+ and pSTAT3+ cells and IL-17 expression occurred later (6th month). These findings corroborate the increases in the number of SOCS1+ cells in both the 3rd and 6th months, with concomitant decreases in SOCS3+ cells at the same time points. Our results demonstrated that beginning with the initiation of COPD development, there was a downregulation of the anti-inflammatory response mediated by SOCS and STAT proteins. These results highlight the importance of intracellular signaling in Th17/Treg imbalance and the identification of possible targets for future therapeutic approaches.

Chronic exposure to diesel particles worsened emphysema and increased M2-like phenotype macrophages in a PPE-induced model.

Chronic exposure to ambient levels of air pollution induces respiratory illness exacerbation by increasing inflammatory responses and apoptotic cells in pulmonary tissues. The ineffective phagocytosis of these apoptotic cells (efferocytosis) by macrophages has been considered an important factor in these pathological mechanisms. Depending on microenvironmental stimuli, macrophages can assume different phenotypes with different functional actions. M1 macrophages are recognized by their proinflammatory activity, whereas M2 macrophages play pivotal roles in responding to microorganisms and in efferocytosis to avoid the progression of inflammatory conditions. To verify how exposure to air pollutants interferes with macrophage polarization in emphysema development, we evaluated the different macrophage phenotypes in a PPE- induced model with the exposure to diesel exhaust particles. C57BL/6 mice received intranasal instillation of porcine pancreatic elastase (PPE) to induce emphysema, and the control groups received saline. Both groups were exposed to diesel exhaust particles or filtered air for 60 days according to the groups. We observed that both the diesel and PPE groups had an increase in alveolar enlargement, collagen and elastic fibers in the parenchyma and the number of macrophages, lymphocytes and epithelial cells in BAL, and these responses were exacerbated in animals that received PPE instillation prior to exposure to diesel exhaust particles. The same response pattern was found inCaspase-3 positive cell analysis, attesting to an increase in cell apoptosis, which is in agreement with the increase in M2 phenotype markers, measured by RT-PCR and flow cytometry analysis. We did not verify differences among the groups for the M1 phenotype. In conclusion, our results showed that both chronic exposure to diesel exhaust particles and PPE instillation induced inflammatory conditions, cell apoptosis and emphysema development, as well as an increase in M2 phenotype macrophages, and the combination of these two factors exacerbated these responses. The predominance of the M2-like phenotype likely occurred due to the increased demand for efferocytosis. However, M2 macrophage activity was ineffective, resulting in emphysema development and worsening of symptoms.

Particularities and Clinical Applicability of Saccharin Transit Time Test.

Introduction The importance of mucociliary clearance (MCC) for the respiratory system homeostasis is clear. Therefore, evaluating this defense mechanism is fundamental in scientific research and in the clinical practice of pulmonology and of associated areas. However, MCC evaluation has not been so usual due to the complexity of methods that use radiolabeled particles. Nevertheless, as an interesting alternative, there is the saccharin transit time (STT) test. This method is reproducible, simple to perform, noninvasive, does not demand high costs, and has been widely used in studies of nasal MCC. Although the STT test is widely used, there is still lack of a detailed description of its realization. Objective The present literature review aims to provide basic information related to the STT test and to present the findings of the previous studies that used this method, discussing variations in its execution, possible influences on the obtained results and limitations of the method, as well as to relate our experience with the use of STT in researches. Data Synthesis There are several factors that can alter the results obtained from STT tests, which would raise difficulties with proper interpretation and with the discussion of the results among different studies. Conclusions Saccharin transit time is a widely used method for the evaluation of nasal MCC, and therefore, the standardization related to the previous and concurrent to test orientations, and also its execution, become essential to improve its accuracy, and allow comparisons among different studies.

Extracellular Matrix Component Remodeling in Respiratory Diseases: What Has Been Found in Clinical and Experimental Studies?

Changes in extracellular matrix (ECM) components in the lungs are associated with the progression of respiratory diseases, such as asthma, chronic obstructive pulmonary disease (COPD), and acute respiratory distress syndrome (ARDS). Experimental and clinical studies have revealed that structural changes in ECM components occur under chronic inflammatory conditions, and these changes are associated with impaired lung function. In bronchial asthma, elastic and collagen fiber remodeling, mostly in the airway walls, is associated with an increase in mucus secretion, leading to airway hyperreactivity. In COPD, changes in collagen subtypes I and III and elastin, interfere with the mechanical properties of the lungs, and are believed to play a pivotal role in decreased lung elasticity, during emphysema progression. In ARDS, interstitial edema is often accompanied by excessive deposition of fibronectin and collagen subtypes I and III, which can lead to respiratory failure in the intensive care unit. This review uses experimental models and human studies to describe how inflammatory conditions and ECM remodeling contribute to the loss of lung function in these respiratory diseases.

Microenvironmental stimuli induce different macrophage polarizations in experimental models of emphysema.

Macrophages play a pivotal role in the development of emphysema and depending on the microenvironment stimuli can be polarized into M1- or M2-like macrophage phenotypes. We compared macrophage polarizations in cigarette smoke (CS)- and porcine pancreatic elastase (PPE)-induced emphysema models. C57BL/6 mice were subdivided into four experimental groups. In the PPE group, animals received an intranasal instillation of PPE (0.677 IU); in the saline group, animals received an intranasal instillation of saline (0.9%). Animals from both groups were euthanized on day 28. In the CS group, animals were exposed to CS for 30 min, twice a day, 5 days per week for 12 weeks. In the control group, animals received filtered air. We observed an increase in total macrophages for both experimental models. For M1-like macrophage markers, we observed an increase in TNF-α+ and IFN-γ+ cells, Cxcl-9 and Cxcl-10 expressions in PPE and CS groups. Only in the CS group, we detected an increased expression of IL-12b For M2-like macrophages markers we observed a down regulation in IL-10, IL-4, IL-13, Arg1 and Fizz1 and an increase of TGF-ß+ cells in the PPE group, while for the CS group there was an increase in TGF-ß+ cells and IL-10 expression. All exposure groups were compared to their respective controls. In summary, we demonstrated that CS- and PPE-induced models resulted in different microenvironmental stimuli. CS exposure induced an environmental stimulus related to M1- and M2-like macrophage phenotypes similar to previous results described in COPD patients, whereas the elastase-induced model provided an environmental stimulus related only to the M1 phenotype.

The Th17/Treg Cytokine Imbalance in Chronic Obstructive Pulmonary Disease Exacerbation in an Animal Model of Cigarette Smoke Exposure and Lipopolysaccharide Challenge Association.

We proposed an experimental model to verify the Th17/Treg cytokine imbalance in COPD exacerbation. Forty C57BL/6 mice were exposed to room air or cigarette smoke (CS) (12 ± 1 cigarettes, twice a day, 30 min/exposure and 5 days/week) and received saline (50 µl) or lipopolysaccharide (LPS) (1 mg/kg in 50 µl of saline) intratracheal instillations. We analyzed the mean linear intercept, epithelial thickness and inflammatory profiles of the bronchoalveolar lavage fluid and lungs. We evaluated macrophages, neutrophils, CD4+ and CD8+ T cells, Treg cells, and IL-10+ and IL-17+ cells, as well as STAT-3, STAT-5, phospho-STAT3 and phospho-STAT5 levels using immunohistochemistry and IL-17, IL-6, IL-10, INF-γ, CXCL1 and CXCL2 levels using ELISA. The study showed that CS exposure and LPS challenge increased the numbers of neutrophils, macrophages, and CD4+ and CD8+ T cells. Simultaneous exposure to CS/LPS intensified this response and lung parenchymal damage. The densities of Tregs and IL-17+ cells and levels of IL-17 and IL-6 were increased in both LPS groups, while IL-10 level was only increased in the Control/LPS group. The increased numbers of STAT-3, phospho-STAT3, STAT-5 and phospho-STAT5+ cells corroborated the increased numbers of IL-17+ and Treg cells. These findings point to simultaneous challenge with CS and LPS exacerbated the inflammatory response and induced diffuse structural changes in the alveolar parenchyma characterized by an increase in Th17 cytokine release. Although the Treg cell differentiation was observed, the lack of IL-10 expression and the decrease in the density of IL-10+ cells observed in the CS/LPS group suggest that a failure to release this cytokine plays a pivotal role in the exacerbated inflammatory response in this proposed model.

Th17/Treg imbalance in COPD progression: A temporal analysis using a CS-induced model.

BACKGROUND: The imbalance between pro- and anti-inflammatory immune responses plays a pivotal role in chronic obstructive pulmonary disease (COPD) development and progression. To clarify the pathophysiological mechanisms of this disease, we performed a temporal analysis of immune response-mediated inflammatory progression in a cigarette smoke (CS)-induced mouse model with a focus on the balance between Th17 and Treg responses. METHODS: C57BL/6 mice were exposed to CS for 1, 3 or 6 months to induce COPD, and the control groups were maintained under filtered air conditions for the same time intervals. We then performed functional (respiratory mechanics) and structural (alveolar enlargement) analyses. We also quantified the NF-κB, TNF-α, CD4, CD8, CD20, IL-17, IL-6, FOXP3, IL-10, or TGF-ß positive cells in peribronchovascular areas and assessed FOXP3 and IL-10 expression through double-label immunofluorescence. Additionally, we evaluated the gene expression of NF-κB and TNF in bronchiolar epithelial cells. RESULTS: Our CS-induced COPD model exhibited an increased proinflammatory immune response (increased expression of the NF-κB, TNF-α, CD4, CD8, CD20, IL-17, and IL-6 markers) with a concomitantly decreased anti-inflammatory immune response (FOXP3, IL-10, and TGF-ß markers) compared with the control mice. These changes in the immune responses were associated with increased alveolar enlargement and impaired lung function starting on the first month and third month of CS exposure, respectively, compared with the control mice. CONCLUSION: Our results showed that the microenvironmental stimuli produced by the release of cytokines during COPD progression lead to a Th17/Treg imbalance.

Particularities and clinical applicability of saccharin transit time test

Introduction: The importance ofmucociliary clearance (MCC) for the respiratory system homeostasis is clear. Therefore, evaluating this defense mechanism is fundamental in scientific research and in the clinical practice of pulmonology and of associated areas. However, MCC evaluation has not been so usual due to the complexity ofmethods that use radiolabeled particles. Nevertheless, as an interesting alternative, there is the saccharin transit time (STT) test. This method is reproducible, simple to perform, noninvasive, does notdemand high costs, and has been widely used in studies of nasalMCC. Although the STT test is widely used, there is still lack of a detailed description of its realization. Objective: The present literature review aims to provide basic information related to the STT test andto present the findings of the previous studies that usedthismethod, discussing variations in its execution, possible influences on the obtained results and limitations of the method, as well as to relate our experience with the use of STT in researches. Data Synthesis: There are several factors that can alter the results obtained from STT tests, which would raise difficulties with proper interpretation and with the discussion of the results among different studies. Conclusions: Saccharin transit time is awidely usedmethod for the evaluation of nasal MCC, and therefore, the standardization related to the previous and concurrent to test orientations, and also its execution, become essential to improve its accuracy, and allow comparisons among different studies (AU)

The tick-derived rBmTI-A protease inhibitor attenuates the histological and functional changes induced by cigarette smoke exposure.

INTRODUCTION: Smoking is the main risk factor for chronic obstructive pulmonary disease development and cigarette smoke (CS) exposure is considered an important approach to reproduce in rodents this human disease. We have previously shown that in an elastase-induced model of emphysema, the administration of a protease inhibitor (rBmTI-A) prevented and attenuated tissue destruction in mice. Thus, in this study we aimed to verify the effects of rBmTI-A administration on the physiopathological mechanisms of CS-induced emphysema. METHODS: Mice (C57BL/6) were exposed to CS or room air for 12 weeks. In this period, 3 nasal instillations of rBmTI-A inhibitor or its vehicle were performed. After euthanasia, respiratory mechanics were evaluated and lungs removed for analysis of mean linear intercept, volume proportion of collagen and elastic fibers, density of polymorphonuclear cells, macrophages, and density of positive cells for MMP-12, MMP-9, TIMP-1 and gp91phox. RESULTS: The rBmTI-A administration improved tissue elastance, decreased alveolar enlargement and collagen fibers accumulation to control levels and attenuated elastic fibers accumulation in animals exposed to CS. There was an increase of MMP-12, MMP-9 and macrophages in CS groups and the rBmTIA only decreased the number of MMP-12 positive cells. Also, we demonstrated an increase in gp91phox in CS treated group and in TIMP-1 levels in both rBmTI-A treated groups. CONCLUSION: In summary, the rBmTI-A administration attenuated emphysema development by an increase of gp91phox and TIMP-1, accompanied by a decrease in MMP-12 levels.

Regulatory T-Cell Distribution within Lung Compartments in COPD.

The importance of the adaptive immune response, specifically the role of regulatory T (Treg) cells in controlling the obstruction progression in smokers, has been highlighted. To quantify the adaptive immune cells in different lung compartments, we used lung tissues from 21 never-smokers without lung disease, 22 current and/or ex-smokers without lung disease (NOS) and 13 current and/or ex-smokers with chronic obstructive pulmonary disease (COPD) for histological analysis. We observed increased T, B, IL-17 and BAFF+ cells in small and large airways of COPD individuals; however, in the NOS, we only observed increase in T and IL-17+ cells only in small airways. A decrease in the density of Treg+, TGF-ß+ and IL-10+ in small and large airways was observed only in COPD individuals. In the lymphoid tissues, Treg, T,B-cells and BAFF+ cells were also increased in COPD; however, changes in Treg inhibitory associated cytokines were not observed in this compartment. Therefore, our results suggest that difference in Treg+ cell distributions in lung compartments and the decrease in TGF-ß+ and IL-10+ cells in the airways may lead to the obstruction in smokers.

A murine model of elastase- and cigarette smoke-induced emphysema.

OBJECTIVE:: To describe a murine model of emphysema induced by a combination of exposure to cigarette smoke (CS) and instillation of porcine pancreatic elastase (PPE). METHODS:: A total of 38 C57BL/6 mice were randomly divided into four groups: control (one intranasal instillation of 0.9% saline solution); PPE (two intranasal instillations of PPE); CS (CS exposure for 60 days); and CS + PPE (two intranasal instillations of PPE + CS exposure for 60 days). At the end of the experimental protocol, all animals were anesthetized and tracheostomized for calculation of respiratory mechanics parameters. Subsequently, all animals were euthanized and their lungs were removed for measurement of the mean linear intercept (Lm) and determination of the numbers of cells that were immunoreactive to macrophage (MAC)-2 antigen, matrix metalloproteinase (MMP)-12, and glycosylated 91-kDa glycoprotein (gp91phox) in the distal lung parenchyma and peribronchial region. RESULTS:: Although there were no differences among the four groups regarding the respiratory mechanics parameters assessed, there was an increase in the Lm in the CS + PPE group. The numbers of MAC-2-positive cells in the peribronchial region and distal lung parenchyma were higher in the CS + PPE group than in the other groups, as were the numbers of cells that were positive for MMP-12 and gp91phox, although only in the distal lung parenchyma. CONCLUSIONS:: Our model of emphysema induced by a combination of PPE instillation and CS exposure results in a significant degree of parenchymal destruction in a shorter time frame than that employed in other models of CS-induced emphysema, reinforcing the importance of protease-antiprotease imbalance and oxidant-antioxidant imbalance in the pathogenesis of emphysema. OBJETIVO:: Descrever um modelo murino de enfisema induzido por exposição a fumaça de cigarro (FC) e instilação de elastase pancreática porcina (EPP). MÉTODOS:: Trinta e oito camundongos C57BL/6 foram aleatoriamente divididos em quatro grupos: controle (uma instilação intranasal de solução salina a 0,9%); EPP (duas instilações intranasais de EPP); FC (exposição a FC durante 60 dias) e FC + EPP (duas instilações intranasais de EPP + exposição a FC durante 60 dias). No fim do protocolo experimental, todos os animais foram anestesiados e traqueostomizados para o cálculo de parâmetros de mecânica respiratória. Em seguida, todos os animais foram sacrificados e seus pulmões foram removidos para a medição da intercepção linear média (Lm) e a determinação do número de células imunorreativas a antígeno macrofágico (MAC)-2, metaloproteinase da matriz (MMP)-12 e glicoproteína glicosilada de 91 kDa (gp91phox) no parênquima pulmonar distal e na região peribrônquica. RESULTADOS:: Embora não tenha havido diferenças entre os quatro grupos quanto aos parâmetros de mecânica respiratória avaliados, houve aumento da Lm no grupo FC + EPP. O número de células positivas para MAC-2 na região peribrônquica e no parênquima pulmonar distal foi maior no grupo FC + EPP do que nos outros grupos, assim como o foi o número de células positivas para MMP-12 e gp91phox, porém somente no parênquima pulmonar distal. CONCLUSÕES:: Nosso modelo de enfisema induzido por instilação de EPP e exposição a FC resulta em um grau significativo de destruição parenquimatosa em um período de tempo menor que o empregado em outros modelos de enfisema induzido por FC, o que reforça a importância do desequilíbrio entre proteases e antiproteases e entre oxidantes e antioxidantes na patogênese do enfisema.

A murine model of elastase- and cigarette smoke-induced emphysema / Modelo murino de enfisema induzido por instilação de elastase e exposição a fumaça de cigarro

ABSTRACT Objective: To describe a murine model of emphysema induced by a combination of exposure to cigarette smoke (CS) and instillation of porcine pancreatic elastase (PPE). Methods: A total of 38 C57BL/6 mice were randomly divided into four groups: control (one intranasal instillation of 0.9% saline solution); PPE (two intranasal instillations of PPE); CS (CS exposure for 60 days); and CS + PPE (two intranasal instillations of PPE + CS exposure for 60 days). At the end of the experimental protocol, all animals were anesthetized and tracheostomized for calculation of respiratory mechanics parameters. Subsequently, all animals were euthanized and their lungs were removed for measurement of the mean linear intercept (Lm) and determination of the numbers of cells that were immunoreactive to macrophage (MAC)-2 antigen, matrix metalloproteinase (MMP)-12, and glycosylated 91-kDa glycoprotein (gp91phox) in the distal lung parenchyma and peribronchial region. Results: Although there were no differences among the four groups regarding the respiratory mechanics parameters assessed, there was an increase in the Lm in the CS + PPE group. The numbers of MAC-2-positive cells in the peribronchial region and distal lung parenchyma were higher in the CS + PPE group than in the other groups, as were the numbers of cells that were positive for MMP-12 and gp91phox, although only in the distal lung parenchyma. Conclusions: Our model of emphysema induced by a combination of PPE instillation and CS exposure results in a significant degree of parenchymal destruction in a shorter time frame than that employed in other models of CS-induced emphysema, reinforcing the importance of protease-antiprotease imbalance and oxidant-antioxidant imbalance in the pathogenesis of emphysema.

RESUMO Objetivo: Descrever um modelo murino de enfisema induzido por exposição a fumaça de cigarro (FC) e instilação de elastase pancreática porcina (EPP). Métodos: Trinta e oito camundongos C57BL/6 foram aleatoriamente divididos em quatro grupos: controle (uma instilação intranasal de solução salina a 0,9%); EPP (duas instilações intranasais de EPP); FC (exposição a FC durante 60 dias) e FC + EPP (duas instilações intranasais de EPP + exposição a FC durante 60 dias). No fim do protocolo experimental, todos os animais foram anestesiados e traqueostomizados para o cálculo de parâmetros de mecânica respiratória. Em seguida, todos os animais foram sacrificados e seus pulmões foram removidos para a medição da intercepção linear média (Lm) e a determinação do número de células imunorreativas a antígeno macrofágico (MAC)-2, metaloproteinase da matriz (MMP)-12 e glicoproteína glicosilada de 91 kDa (gp91phox) no parênquima pulmonar distal e na região peribrônquica. Resultados: Embora não tenha havido diferenças entre os quatro grupos quanto aos parâmetros de mecânica respiratória avaliados, houve aumento da Lm no grupo FC + EPP. O número de células positivas para MAC-2 na região peribrônquica e no parênquima pulmonar distal foi maior no grupo FC + EPP do que nos outros grupos, assim como o foi o número de células positivas para MMP-12 e gp91phox, porém somente no parênquima pulmonar distal. Conclusões: Nosso modelo de enfisema induzido por instilação de EPP e exposição a FC resulta em um grau significativo de destruição parenquimatosa em um período de tempo menor que o empregado em outros modelos de enfisema induzido por FC, o que reforça a importância do desequilíbrio entre proteases e antiproteases e entre oxidantes e antioxidantes na patogênese do enfisema.

Influence of Smoking Consumption and Nicotine Dependence Degree in Cardiac Autonomic Modulation / Influência do Consumo Tabagístico e Grau de Dependência Nicotínica na Modulação Autonômica Cardíaca

Abstract Background: Smoking consumption alters cardiac autonomic function. Objective: Assess the influence of the intensity of smoking and the nicotine dependence degree in cardiac autonomic modulation evaluated through index of heart rate variability (HRV). Methods: 83 smokers, of both genders, between 50 and 70 years of age and with normal lung function were divided according to the intensity of smoking consumption (moderate and severe) and the nicotine dependency degree (mild, moderate and severe). The indexes of HRV were analyzed in rest condition, in linear methods in the time domain (TD), the frequency domain (FD) and through the Poincaré plot. For the comparison of smoking consumption, unpaired t test or Mann-Whitney was employed. For the analysis between the nicotine dependency degrees, we used the One-way ANOVA test, followed by Tukey's post test or Kruskal-Wallis followed by Dunn's test. The significance level was p < 0,05. Results: Differences were only found when compared to the different intensities of smoking consumption in the indexes in the FD. LFun (62.89 ± 15.24 vs 75.45 ± 10.28), which corresponds to low frequency spectrum component in normalized units; HFun (37.11 ± 15.24 vs 24.55 ± 10.28), which corresponds to high frequency spectrum component in normalized units and in the LF/HF ratio (2.21 ± 1.47 vs 4.07 ± 2.94). However, in the evaluation of nicotine dependency, significant differences were not observed (p > 0.05). Conclusion: Only the intensity of smoking consumption had an influence over the cardiac autonomic modulation of the assessed tobacco smokers. Tobacco smokers with severe intensity of smoking consumption presented a lower autonomic modulation than those with moderate intensity.

Resumo Fundamento: O tabagismo altera a função autonômica cardíaca. Objetivo: Avaliar a influência da intensidade do consumo tabagístico e do grau de dependência nicotínica na modulação autonômica cardíaca avaliada por meio de índices de variabilidade da frequência cardíaca (VFC). Métodos: 83 tabagistas, de ambos os sexos, faixa etária entre 50 e 70 anos de idade e com função pulmonar normal foram divididos de acordo com a intensidade do consumo tabagístico (moderado e grave) e o grau de dependência nicotínica (leve, moderado e grave). Os índices de VFC foram analisados em condição de repouso, em métodos lineares no domínio do tempo (DT), domínio da frequência (DF) e pelo plot de Poincaré. Para comparação do consumo tabagístico, foi utilizado teste t não pareado ou Mann-Whitney. Para análise entre os graus de dependência nicotínica, foi utilizado teste One-way ANOVA seguido de pós-teste de Tukey ou Kruskal-Wallis seguido pelo teste de Dunn. O nível de significância foi de p < 0,05. Resultados: Diferenças só foram encontradas quando comparadas às diferentes intensidades do consumo tabagístico nos índices no DF: LFun (62,89 ± 15,24 vs 75,45 ± 10,28), que corresponde ao componente espectral de baixa frequência em unidades normalizadas; HFun (37,11 ± 15,24 vs 24,55 ± 10,28), que corresponde ao componente espectral de alta frequência em unidades normalizadas e na relação LF/HF (2,21 ± 1,47 vs 4,07 ± 2,94). No entanto, na avaliação da dependência nicotínica não foram observadas diferenças significativas (p > 0,05). Conclusão: Apenas a intensidade do consumo tabagístico promoveu influências sobre a modulação autonômica cardíaca dos tabagistas avaliados. Tabagistas com intensidade de consumo tabagístico grave apresentaram menor modulação autonômica do que tabagistas moderados.

Influence of Smoking Consumption and Nicotine Dependence Degree in Cardiac Autonomic Modulation.

BACKGROUND: Smoking consumption alters cardiac autonomic function. OBJECTIVE: Assess the influence of the intensity of smoking and the nicotine dependence degree in cardiac autonomic modulation evaluated through index of heart rate variability (HRV). METHODS: 83 smokers, of both genders, between 50 and 70 years of age and with normal lung function were divided according to the intensity of smoking consumption (moderate and severe) and the nicotine dependency degree (mild, moderate and severe). The indexes of HRV were analyzed in rest condition, in linear methods in the time domain (TD), the frequency domain (FD) and through the Poincaré plot. For the comparison of smoking consumption, unpaired t test or Mann-Whitney was employed. For the analysis between the nicotine dependency degrees, we used the One-way ANOVA test, followed by Tukey's post test or Kruskal-Wallis followed by Dunn's test. The significance level was p < 0,05. RESULTS: Differences were only found when compared to the different intensities of smoking consumption in the indexes in the FD. LFun (62.89 ± 15.24 vs 75.45 ± 10.28), which corresponds to low frequency spectrum component in normalized units; HFun (37.11 ± 15.24 vs 24.55 ± 10.28), which corresponds to high frequency spectrum component in normalized units and in the LF/HF ratio (2.21 ± 1.47 vs 4.07 ± 2.94). However, in the evaluation of nicotine dependency, significant differences were not observed (p > 0.05). CONCLUSION: Only the intensity of smoking consumption had an influence over the cardiac autonomic modulation of the assessed tobacco smokers. Tobacco smokers with severe intensity of smoking consumption presented a lower autonomic modulation than those with moderate intensity.

Acute Mucociliary Clearance Response to Aerobic Exercise in Smokers.

BACKGROUND: Mucociliary clearance is the main defense mechanism of the respiratory system, and it is influenced by several stimuli, including aerobic exercise and cigarette smoking. We evaluated the acute response of mucociliary clearance to aerobic exercise in smokers and nonsmokers compared with that found after acute smoking and smoking combined with exercise. Also, we investigated whether there was a correlation between mucociliary clearance and the autonomic nervous system under these conditions. METHODS: Twenty-one smokers were evaluated for mucociliary clearance by saccharin transit time (STT), and the response of the autonomic nervous system was evaluated by heart rate variability after aerobic exercise, after exercise followed by smoking, after acute smoking, and after rest. For comparison, 17 nonsmokers were also assessed during exercise. Repeated-measures analysis of variance with the Tukey test or the Friedman test followed by the Dunn test was used to evaluate the STT, autonomic response, and other variables to exercise and/or smoking in smokers. A paired t test or Wilcoxon test was used to analyze responses to exercise in nonsmokers. Correlations were evaluated using Pearson or Spearman coefficients. RESULTS: The STT was reduced after exercise in both groups, with similar responses between them. Other stimuli also reduced the STT. The STT showed a negative correlation with sympathetic activity in smokers and a positive correlation with the parasympathetic system in nonsmokers. CONCLUSIONS: Although impaired in smokers, mucociliary clearance responded to the stimulus of exercise, as demonstrated by similar STTs compared with nonsmokers. This response was correlated with the autonomic nervous system in both groups. In smokers, mucociliary clearance also responded to the stimuli of smoking and exercise followed by smoking.

Nasal Mucociliary Clearance in Subjects With COPD After Smoking Cessation.

BACKGROUND: Exposure to cigarette smoke causes significant impairment in mucociliary clearance (MCC), which predisposes patients to secretion retention and recurrent airway infections that play a role in exacerbations of COPD. To determine whether smoking cessation may influence MCC and frequency of exacerbations, the following groups were evaluated: ex-smokers with COPD, smokers with COPD, current smokers with normal lung function, and nonsmokers with normal lung function. METHODS: Ninety-three subjects were divided into 4 groups: ex-smokers with COPD (n = 23, 62.4 ± 8.0 y, 13 males), smokers with COPD (n = 17, 58.2 ± 8.0 y, 6 males), current smokers (n = 27, 61.5 ± 6.4 y, 17 males), and nonsmokers (n = 26, 60.8 ± 11.3 y, 7 males). MCC was evaluated using the saccharin transit time (STT) test, and the frequency of exacerbations in the last year was assessed by questionnaire. The Kruskal-Wallis test followed by Dunn's test were used to compare STT among groups, and the Goodman test was used to compare the frequency of exacerbations. RESULTS: STT of smokers with COPD (16.5 [11-28] min; median [interquartile range 25-75%]) and current smokers (15.9 [10-27] min) was longer compared with ex-smokers with COPD (9.7 [6-12] min) and nonsmokers (8 [6-16] min) (P < .001). There was no difference in STT values between smokers with COPD and current smokers, and these values in ex-smokers with COPD were similar to the control group (P > .05). The frequency of exacerbations was lower in ex-smokers with COPD compared with smokers with COPD. CONCLUSIONS: One year after smoking cessation, subjects with COPD had improved mucociliary clearance.

Nasal and systemic inflammatory profile after short term smoking cessation.

INTRODUCTION: Smoking cessation promotes health benefits and, despite cigarette smoking be an important pro inflammatory stimulus, there are few studies concerning the nasal and systemic inflammation; as well as the mucociliary clearance behavior in smokers after short period of smoking cessation. AIM: To evaluate the nasal and systemic inflammatory markers and mucociliary clearance behavior after 30 days of cigarette smoking abstinence. METHODS: Twenty-five smokers were included and divided into two groups: abstinent smokers (n = 14) and current smokers (n = 11). Tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, IL-8 and IL-10 were measured on nasal lavage and blood serum samples by ELISA at baseline and after 30 days. The mucociliary clearance, exhaled carbon monoxide (exCO) and carboxyhemoglobin (HbCO) were also measured at the same moments. RESULTS: There was a decrease of TNF-α level only in blood serum at 30 days of abstinence compared to current smokers. The mucociliary clearance improved and there was a reduction in exCO and HbCO (p < 0.05 for all) after 30 days of smoking cessation. CONCLUSION: The short term smoking abstinence decreased systemic inflammation and improved nasal mucociliary clearance, despite not having changed the nasal inflammation.