Aerobic exercise attenuates pulmonary inflammation induced by Streptococcus pneumoniae

Respiratory issues in patients with multiple sclerosis as a risk factor during SARS-CoV-2 infection: a potential role for exercise

Coronavirus disease-2019 (COVID-19) is associated with cytokine storm and is characterized by acute respiratory distress syndrome (ARDS) and pneumonia problems. The respiratory system is a place of inappropriate activation of the immune system in people with multiple sclerosis (MS), and this may cause damage to the lung and worsen both MS and infections.The concerns for patients with multiple sclerosis are because of an enhance risk of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The MS patients pose challenges in this pandemic situation, because of the regulatory defect of autoreactivity of the immune system and neurological and respiratory tract symptoms. In this review, we first indicate respiratory issues associated with both diseases. Then, the main mechanisms inducing lung damages and also impairing the respiratory muscles in individuals with both diseases is discussed. At the end, the leading role of physical exercise on mitigating respiratory issues inducing mechanisms is meticulously evaluated.

Risk Factors of Severe COVID-19: A Review of Host, Viral and Environmental Factors

The clinical course and outcome of COVID-19 are highly variable, ranging from asymptomatic infections to severe disease and death. Understanding the risk factors of severe COVID-19 is relevant both in the clinical setting and at the epidemiological level. Here, we provide an overview of host, viral and environmental factors that have been shown or (in some cases) hypothesized to be associated with severe clinical outcomes. The factors considered in detail include the age and frailty, genetic polymorphisms, biological sex (and pregnancy), co- and superinfections, non-communicable comorbidities, immunological history, microbiota, and lifestyle of the patient; viral genetic variation and infecting dose; socioeconomic factors; and air pollution. For each category, we compile (sometimes conflicting) evidence for the association of the factor with COVID-19 outcomes (including the strength of the effect) and outline possible action mechanisms. We also discuss the complex interactions between the various risk factors.

The effects of exercise training on the lungs and cardiovascular function of animals exposed to diesel exhaust particles and gases

Air pollution has been identified as one of the main environmental risks to health. Since exercise training seems to act as an anti-inflammatory modulator, our hypothesis is that exercise training prevents damage to respiratory and cardiovascular function caused by diesel exhaust particle (DEP) exposure. This study aimed to evaluate whether aerobic exercise training prior to DEP exposure prevents inflammatory processes in the pulmonary and cardiovascular systems. Therefore, BALB/C male mice were or were not submitted to a 10-week exercise training protocol (5×/week, 1 h/d), and after four weeks, they were exposed to DEP in a chamber with 24 μg/m³ PM2.5 or filtered air. Heart rate variability, lung mechanics and bronchoalveolar lavage fluid, cytokines and polymorphonuclear cells in the lung parenchyma were evaluated. Exposure to DEPs reduced heart rate variability and the elastance of the respiratory system and increased the number of cells in bronchoalveolar lavage fluid, as well as macrophages, neutrophils and lymphocytes, the density of polymorphonuclear cells and the proportion of collagen fibres in the lung parenchyma. Additionally, DEP-exposed animals showed increased expression of IL-23 and IL-12p40 (proinflammatory cytokines) and inducible nitric oxide synthase. Exercise training avoided the increases in all these inflammatory parameters, except the elastance of the respiratory system, the amount of collagen fibres and the expression of inducible nitric oxide synthase. Additionally, trained animals showed increased expression of the anti-inflammatory cytokine IL-1ra. Although our data showed a reduction in proinflammatory markers and an increase in markers of the anti-inflammatory pathway, these changes were not sufficient to prevent damage to the lung and cardiovascular function induced by DEPs. Based on these data, we propose that aerobic exercise training prevents the lung inflammatory process induced by DEPs, although it was not sufficient to avoid chronic damage, such as a loss of lung function or cardiovascular events.

Combined exercise training improved exercise capacity and lung inflammation in rats with hepatopulmonary syndrome

AIM

Physical exercise training attenuates pulmonary inflammation, but its effects on impaired respiratory function caused by hepatopulmonary syndrome (HPS) have not been evaluated. We determined if the combination of moderate intensity aerobic and resistance training during HPS development modifies exercise capacity, respiratory system mechanics, and lung inflammation responses.

MAIN METHODS

Wistar rats were randomly divided into sham, HPS, and HPS + combined exercise training groups. Fifteen days after HPS induction, a moderate intensity aerobic plus resistance exercise training protocol was performed five times a week for 5 weeks on alternate days. Exercise capacity, respiratory system mechanics, lung inflammation, pulmonary morphology, and immunohistochemistry were evaluated.

KEY FINDINGS

Overall, our findings indicated that combined exercise training efficiently increased the maximal running and resistance capacity of HPS animals. The training regimen reduced the expression of P2X7 in parenchymal leukocytes (P < 0.01), partially restored the expression of interleukin-10 in airway epithelium (P < 0.01), and increased the expression of TFPI in the airway epithelium (P < 0.01) as well as reduced its expression in parenchymal leukocytes (P < 0.01). However, exercise training did not attenuate HPS-induced respiratory mechanical derangements or lung tissue remodeling.

SIGNIFICANCE

Combined exercise training can elicit adaptation with regard to both maximal running capacity and maximum strength and modify the expression of P2X7 and TFPI in parenchymal leukocytes and that of IL-10 in airway epithelium.

Enhancing oxygenation of patients with coronavirus disease 2019: Effects on immunity and other health-related conditions

Coronavirus disease 2019 (COVID-19) distresses the pulmonary system causing acute respiratory distress syndrome, which might lead to death. There is no cure for COVID-19 infection. COVID-19 is a self-limited infection, and the methods that can enhance immunity are strongly required. Enhancing oxygenation is one safe and effective intervention to enhance immunity and pulmonary functions. This review deliberates the probable influences of enhancing oxygenation on immunity and other health-connected conditions in patients with COVID-19. An extensive search was conducted through Web of Science, Scopus, Medline databases, and EBSCO for the influence of enhancing oxygenation on immunity, pulmonary functions, psycho-immune hormones, and COVID-19 risk factors. This search included clinical trials and literature and systematic reviews. This search revealed that enhancing oxygenation has a strong effect on improving immunity and pulmonary functions and psycho-immune hormones. Also, enhancing oxygenation has a self-protective role counter to COVID-19 risk factors. Lastly, this search revealed the recommended safe and effective exercise protocol to enhance oxygenation in patients with COVID-19. Enhancing oxygenation should be involved in managing patients with COVID-19 because of its significant effects on immunity, pulmonary functions, and COVID-19 risk factors. A mild to moderate cycling or walking with 60%-80% Vo2max for 20-60 min performed 2-3 times per week could be a safe and effective aerobic exercise program in patients with COVID-19 to enhance their immunity and pulmonary functions.

The Relevance of a Physical Active Lifestyle and Physical Fitness on Immune Defense: Mitigating Disease Burden, With Focus on COVID-19 Consequences

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a fast spreading virus leading to the development of Coronavirus Disease-2019 (COVID-19). Severe and critical cases are characterized by damage to the respiratory system, endothelial inflammation, and multiple organ failure triggered by an excessive production of proinflammatory cytokines, culminating in the high number of deaths all over the world. Sedentarism induces worse, continuous, and progressive consequences to health. On the other hand, physical activity provides benefits to health and improves low-grade systemic inflammation. The aim of this review is to elucidate the effects of physical activity in physical fitness, immune defense, and its contribution to mitigate the severe inflammatory response mediated by SARS-CoV-2. Physical exercise is an effective therapeutic strategy to mitigate the consequences of SARS-CoV-2 infection. In this sense, studies have shown that acute physical exercise induces the production of myokines that are secreted in tissues and into the bloodstream, supporting its systemic modulatory effect. Therefore, maintaining physical activity influence balance the immune system and increases immune vigilance, and also might promote potent effects against the consequences of infectious diseases and chronic diseases associated with the development of severe forms of COVID-19. Protocols to maintain exercise practice are suggested and have been strongly established, such as home-based exercise (HBE) and outdoor-based exercise (OBE). In this regard, HBE might help to reduce levels of physical inactivity, bed rest, and sitting time, impacting on adherence to physical activity, promoting all the benefits related to exercise, and attracting patients in different stages of treatment for COVID-19. In parallel, OBE must improve health, but also prevent and mitigate COVID-19 severe outcomes in all populations. In conclusion, HBE or OBE models can be a potent strategy to mitigate the progress of infection, and a coadjutant therapy for COVID-19 at all ages and different chronic conditions.

Social and Psychophysiological Consequences of the COVID-19 Pandemic: An Extensive Literature Review

The Coronavirus Disease 2019 (COVID-19) pandemic, now a global health crisis, has surprised health authorities around the world. Recent studies suggest that the measures taken to curb the spread of the COVID-19 outbreak have generated issues throughout the population. Thus, it is necessary to establish and identify the possible risk factors related to the psychosocial and psychophysiological strain during the COVID-19 outbreak. The present extensive literature review assesses the social, psychological, and physiological consequences of COVID-19, reviewing the impact of quarantine measures, isolation, vast human loss, social and financial consequences in the family's economies, and its impact on the psychological health of the population. We also discussed the effect of psychophysiological factors, considering the impact of physical inactivity and modifications in nutritional habits, at psychological and physiological levels. The present review includes an actualized to date bibliography, articles for which were methodologically analyzed to verify they met the standards of quality and scientific accuracy. Authors understand the pandemic as a multifactorial event for which only a profound and extensive analysis would lead to better compression and efficient intervention in the near future.

Coronavirus disease-2019: A tocsin to our aging, unfit, corpulent, and immunodeficient society

Acute and chronic respiratory illnesses cause widespread morbidity and mortality, and this class of illness now includes the novel coronavirus severe acute respiratory syndrome that is causing coronavirus disease-2019 (COVID-19). The world is experiencing a major demographic shift toward an older, obese, and physically inactive populace. Risk factor assessments based on pandemic data indicate that those at higher risk for severe illness from COVID-19 include older males, and people of all ages with obesity and related comorbidities such as hypertension and type 2 diabetes. Aging in and of itself leads to negative changes in innate and adaptive immunity, a process termed immunosenescence. Obesity causes systemic inflammation and adversely impacts immune function and host defense in a way that patterns immunosenescence. Two primary prevention strategies to reduce the risk for COVID-19 at both the community and individual levels include mitigation activities and the adoption of lifestyle practices consistent with good immune health. Animal and human studies support the idea that, in contrast to high exercise workloads, regular moderate-intensity physical activity improves immunosurveillance against pathogens and reduces morbidity and mortality from viral infection and respiratory illnesses including the common cold, pneumonia, and influenza. The odds are high that infectious disease pandemics spawned by novel pathogens will continue to inflict morbidity and mortality as the world's population becomes older and more obese. COVID-19 is indeed a wake-up call, a tocsin, to the world that primary prevention countermeasures focused on health behaviors and hygiene demand our full attention and support.

Role of increasing the aerobic capacity on improving the function of immune and respiratory systems in patients with coronavirus (COVID-19): A review

BACKGROUND AND AIMS

COVID-19 is a public world crisis, however, it is a self-limited infection. In COVID-19, the strength of immune and respiratory systems is a critical element. Thus, this review was conducted to demonstrate the short and long term effects of increasing the aerobic capacity on increasing the function and strength of immune and respiratory systems, particularly those essential for overcoming COVID-19 infections and associated disorders.

METHODS

This review was carried out by searching in Web of Science, Scopus, EBSCO, Medline databases. The search was conducted over clinical trials and literature and systematic reviews on the effects of increasing the aerobic capacity on the function and strength of specific immune and respiratory elements essential for overcoming COVID-19 infections.

RESULTS

This review found that increasing the aerobic capacity could produce short-term safe improvements in the function of immune and respiratory systems, particularly those specific for COVID-19 infections. This could be mainly produced through three mechanisms. Firstly, it could improve immunity by increasing the level and function of immune cells and immunoglobulins, regulating CRP levels, and decreasing anxiety and depression. Secondly, it could improve respiratory system functions by acting as an antibiotic, antioxidant, and antimycotic, restoring normal lung tissue elasticity and strength. Lastly, it could act as a protective barrier to decrease COVID-19 risk factors, which helps to decrease the incidence and progression of COVID-19.

CONCLUSION

This review summarizes that increasing the aerobic capacity is recommended because it has potential of improving immune and respiratory functions which would help counter COVID-19.

Preventive effect of exercise training on diabetic kidney disease in ovariectomized rats with type 1 diabetes

IMPACT STATEMENT

To date, no studies have been found evaluating the effects of physical exercise on renal function and structure changes in ovariectomized rats with type 1 diabetes. Therefore, this work emerges with an important tool for strengthening and expanding innovative research on exercise with potential for the prevention of renal diseases in ovariectomized diabetic rats, and future development of studies that seek to increase scientific knowledge about the beneficial effects of physical exercise on renal diseases in humans.

Physical Exercise Induces Immunoregulation of TREG, M2, and pDCs in a Lung Allergic Inflammation Model

The benefits of moderate aerobic physical exercise for allergic asthma are well-known, particularly that of the anti-inflammatory effect that occurs by reducing Th2 responses and lung remodeling. However, the mechanisms of this immunoregulation are still under investigation. In this study, we investigated the possible immunoregulatory mechanisms of lung inflammation induced by moderate aerobic exercise in an experimental asthma model. BALB/c mice were distributed into Control, Exercise (EX), OVA, and OEX groups. OVA and OEX groups were sensitized with ovalbumin (OVA) on days 0, 14, 21, 28, and 42 and were challenged with OVA aerosol three times a week from days 21 to 51. The EX and OEX groups underwent moderate aerobic physical exercise from days 21 to 51 (5 d/w, 1 h/d). The mice were euthanized on day 52. We evaluated pulmonary cytokine production, serum immunoglobulin levels, and the inflammatory cell profile in lung and mediastinal lymph nodes. OVA mice showed increased expression of IL-4, IL-6, IL-10, and TGF-β and decreased macrophage type 2 (M2) recruitment. Physical exercise did not affect the increased antibody production of IgG2a, IgG1, or IgE induced by OVA. Of note, physical exercise alone markedly increased production of anti-inflammatory cytokines such as IL-10 and TGF-β. Physical exercise in OVA-mice also increased the recruitment of M2 in the lungs, as well as the influx and activation of regulatory T cells (Tregs) and CD4 and CD8 lymphocytes. In the draining lymph nodes, it was also observed that physical exercise increased the activation of CD4 T cells, regardless of the presence of OVA. Notably, physical exercise decreased common dendritic cells' (cDCs; pro-inflammatory) expression of co-stimulatory molecules such as CD80, CD86, and ICOSL in the draining lymph nodes, as well as increased ICOSL in plasmacytoid dendritic cells (pDCs; anti-inflammatory). Together, these findings show that physical exercise modulates pulmonary allergic inflammation by increasing Treg and M2 recruitment, as well as pDCs activation, which leads to an increase in anti-inflammatory cytokines and a decrease in pro-inflammatory cells and mediators.

The compelling link between physical activity and the body's defense system

This review summarizes research discoveries within 4 areas of exercise immunology that have received the most attention from investigators: (1) acute and chronic effects of exercise on the immune system, (2) clinical benefits of the exercise-immune relationship, (3) nutritional influences on the immune response to exercise, and (4) the effect of exercise on immunosenescence. These scientific discoveries can be organized into distinctive time periods: 1900-1979, which focused on exercise-induced changes in basic immune cell counts and function; 1980-1989, during which seminal papers were published with evidence that heavy exertion was associated with transient immune dysfunction, elevated inflammatory biomarkers, and increased risk of upper respiratory tract infections; 1990-2009, when additional focus areas were added to the field of exercise immunology including the interactive effect of nutrition, effects on the aging immune system, and inflammatory cytokines; and 2010 to the present, when technological advances in mass spectrometry allowed system biology approaches (i.e., metabolomics, proteomics, lipidomics, and microbiome characterization) to be applied to exercise immunology studies. The future of exercise immunology will take advantage of these technologies to provide new insights on the interactions between exercise, nutrition, and immune function, with application down to the personalized level. Additionally, these methodologies will improve mechanistic understanding of how exercise-induced immune perturbations reduce the risk of common chronic diseases.

Exercise training modifies gut microbiota with attenuated host responses to sepsis in wild-type mice

This study investigated the effects of exercise preconditioning-induced modification in gut microbiota composition and host responses to cecal ligation and puncture (CLP)-induced sepsis. Four-week-old C57BL/6N male mice were randomly assigned to either CLP ( n = 30) or CLP-exercise (CLP+Exe; n = 30) groups. Prior to CLP-induced sepsis, the CLP+Exe mice were subjected to 8 wk of treadmill running. Fecal samples were collected and analyzed by 16S rRNA amplification sequencing to assess gut microbiota composition. Diversity analyses such as principal coordinates analysis and rarefaction curves showed that exercise preconditioning was associated with differences in gut microbiota community structure and species richness. Exercise preconditioning-induced differences in gut microbiota composition were also evident at the family level of taxonomic analysis, with the dominant phyla being Bacteriodetes, Firmicutes, Verrucomicrobia, and, to a lesser extent, Cyanobacteria. Compared with control mice, preconditioned mice had a higher survival rate and less organ damage during the acute phase of sepsis, secondary to attenuation of the host response to septic shock. The current findings suggest that exercise preconditioning-induced modification in gut microbiota composition may lead to an attenuated host response to CLP-induced sepsis in wild-type mice, as shown by increased survival and less organ damage, as well as the establishment of a balance between pro- and anti-inflammatory responses.-Kim, D., Kang, H. Exercise training modifies gut microbiota with attenuated host responses to sepsis in wild-type mice.

Pulmonary and muscle profile in pneumosepsis: A temporal analysis of inflammatory markers

In sepsis, greater understanding of the inflammatory mechanism involved would provide insights into the condition and into its extension to the muscular apparatus in critically ill patients. Therefore, this study evaluates the inflammatory profile of pneumosepsis induced by Klebsiella pneumoniae (K.p.) in lungs and skeletal muscles during the first 72 h. Male BALB/c mice were divided into 4 groups, submitted to intratracheal inoculation of K.p. at a concentration of 2 × 10⁸ (PS) or PBS, and assessed after 24 (PS24), 48 (PS48) and 72 (PS72) hours. The Maximum Physical Capacity Test (MPCT) was performed before and after induction. Pulmonary inflammation was assessed by total cell number, nitric oxide levels (NOx), IL-1β and TNF-α levels in bronchoalveolar lavage fluid (BALF); inflammation and muscle trophism were evaluated by the levels of TNF-α, IL-6, TGF-β and BDNF by ELISA and NF-κB by western blotting in muscle tissue. Cells and colony forming units (CFU) were also analyzed in blood samples. The PS groups showed an increase in total cells in the BALF (p < 0.05), as well in the number of granulocytes in the blood (p < 0.05) and a decrease in performance in the MPCT (p < 0.05). NOx levels showed significant increase in PS72, when compared to Control group (p = 0.03). The PS24 showed a significant increase lung in TNF-α levels (p < 0.001) and in CFU (p = 0.013). We observed an increase in muscular IL-6 and nuclear NF-κB levels in PS24 group, when compared to PS48 and Control groups (p < 0.05). Nevertheless, mild signs of injury in the skeletal muscle tissue does not support the idea of an early muscular injury in this experimental model, suggesting that the low performance of the animals during the MPCT may be related to lung inflammation.

MODERATE INTENSITY PHYSICAL EXERCISE: PSYCHONEUROIMMUNOLOGICAL ASPECTS

ABSTRACT The literature presents several instances of interaction between the nervous system (NS) and the immune system (IS). These interactions are promoted by several molecules, such as cytokines and hormones, with modulating action for both the NS and IS. In this sense, the two systems may influence each other: changes in behavior may be accompanied by alterations in the IS (e.g., immunosuppression) and immunological disorders, such as infections, may modulate behavior (e.g., anxiety and depression). Considering that chronic stress, in addition to affecting behavior, also modulates the IS and that there is evidence that moderate intensity physical exercise (PE) protects physical and mental health, the objective of this review is to explore the influence of moderate-intensity PE on behavior and immunity. Level of Evidence V; Expert opinion.

Exercise Prevents Enhanced Postoperative Neuroinflammation and Cognitive Decline and Rectifies the Gut Microbiome in a Rat Model of Metabolic Syndrome

Introduction

Postoperative cognitive decline (PCD) can affect in excess of 10% of surgical patients and can be considerably higher with risk factors including advanced age, perioperative infection, and metabolic conditions such as obesity and insulin resistance. To define underlying pathophysiologic processes, we used animal models including a rat model of metabolic syndrome generated by breeding for a trait of low aerobic exercise tolerance. After 35 generations, the low capacity runner (LCR) rats differ 10-fold in their aerobic exercise capacity from high capacity runner (HCR) rats. The LCR rats respond to surgical procedure with an abnormal phenotype consisting of exaggerated and persistent PCD and failure to resolve neuroinflammation. We determined whether preoperative exercise can rectify the abnormal surgical phenotype.

Materials and methods

Following institutional approval of the protocol each of male LCR and male HCR rats were randomly assigned to four groups and subjected to isoflurane anesthesia and tibia fracture with internal fixation (surgery) or anesthesia alone (sham surgery) and to a preoperative exercise regimen that involved walking for 10 km on a treadmill over 6 weeks (exercise) or being placed on a stationary treadmill (no exercise). Feces were collected before and after exercise for assessment of gut microbiome. Three days following surgery or sham surgery the rats were tested for ability to recall a contextual aversive stimulus in a trace fear conditioning paradigm. Thereafter some rats were euthanized and the hippocampus harvested for analysis of inflammatory mediators. At 3 months, the remainder of the rats were tested for memory recall by the probe test in a Morris Water Maze.

Results

Postoperatively, LCR rats exhibited exaggerated cognitive decline both at 3 days and at 3 months that was prevented by preoperative exercise. Similarly, LCR rats had excessive postoperative neuroinflammation that was normalized by preoperative exercise. Diversity of the gut microbiome in the LCR rats improved after exercise.

Discussion

Preoperative exercise eliminated the metabolic syndrome risk for the abnormal surgical phenotype and was associated with a more diverse gut microbiome. Prehabilitation with exercise should be considered as a possible intervention to prevent exaggerated and persistent PCD in high-risk settings.

Voluntary running exercise protects against sepsis-induced early inflammatory and pro-coagulant responses in aged mice

Background

Despite many animal studies and clinical trials, mortality in sepsis remains high. This may be due to the fact that most experimental studies of sepsis employ young animals, whereas the majority of septic patients are elderly (60 − 70 years). The objective of the present study was to examine the sepsis-induced inflammatory and pro-coagulant responses in aged mice. Since running exercise protects against a variety of diseases, we also examined the effect of voluntary running on septic responses in aged mice.

Methods

Male C57BL/6 mice were housed in our institute from 2–3 to 22 months (an age mimicking that of the elderly). Mice were prevented from becoming obese by food restriction (given 70–90% of ad libitum consumption amount). Between 20 and 22 months, a subgroup of mice ran voluntarily on wheels, alternating 1–3 days of running with 1–2 days of rest. At 22 months, mice were intraperitoneally injected with sterile saline (control) or 3.75 g/kg fecal slurry (septic). At 7 h post injection, we examined (1) neutrophil influx in the lung and liver by measuring myeloperoxidase and/or neutrophil elastase in the tissue homogenates by spectrophotometry, (2) interleukin 6 (IL6) and KC in the lung lavage by ELISA, (3) pulmonary surfactant function by measuring percentage of large aggregates, (4) capillary plugging (pro-coagulant response) in skeletal muscle by intravital microscopy, (5) endothelial nitric oxide synthase (eNOS) protein in skeletal muscle (eNOS-derived NO is putative inhibitor of capillary plugging) by immunoblotting, and (6) systemic blood platelet counts by hemocytometry.

Results

Sepsis caused high levels of pulmonary myeloperoxidase, elastase, IL6, KC, liver myeloperoxidase, and capillary plugging. Sepsis also caused low levels of surfactant function and platelet counts. Running exercise increased eNOS protein and attenuated the septic responses.

Conclusions

Voluntary running protects against exacerbated sepsis-induced inflammatory and pro-coagulant responses in aged mice. Protection against pro-coagulant responses may involve eNOS upregulation. The present discovery in aged mice calls for clinical investigation into potential beneficial effects of exercise on septic outcomes in the elderly.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1783-1) contains supplementary material, which is available to authorized users.

Time-course effects of aerobic physical training in the prevention of cigarette smoke-induced COPD

A previous study by our group showed that regular exercise training (ET) attenuated pulmonary injury in an experimental model of chronic exposure to cigarette smoke (CS) in mice, but the time-course effects of the mechanisms involved in this protection remain poorly understood. We evaluated the temporal effects of regular ET in an experimental model of chronic CS exposure. Male C57BL/6 mice were divided into four groups: Control (sedentary + air), Exercise (aerobic training + air), Smoke (sedentary + smoke), and Smoke + Exercise (aerobic training + smoke). Mice were exposed to CS and ET for 4, 8, or 12 wk. Exercise protected mice exposed to CS from emphysema and reductions in tissue damping and tissue elastance after 12 wk (P < 0.01). The total number of inflammatory cells in the bronchoalveolar lavage increased in the Smoke group, mainly due to the recruitment of macrophages after 4 wk, neutrophils and lymphocytes after 8 wk, and lymphocytes and macrophages after 12 wk (P < 0.01). Exercise attenuated this increase in mice exposed to CS. The protection conferred by exercise was mainly observed after exercise adaptation. Exercise increased IL-6 and IL-10 in the quadriceps and lungs (P < 0.05) after 12 wk. Total antioxidant capacity and SOD was increased and TNF-α and oxidants decreased in lungs of mice exposed to CS after 12 wk (P < 0.05). The protective effects of exercise against lung injury induced by cigarette smoke exposure suggests that anti-inflammatory mediators and antioxidant enzymes play important roles in chronic obstructive pulmonary disease development mainly after the exercise adaptation.NEW & NOTEWORTHY These experiments investigated for the first time the temporal effects of regular moderate exercise training in cigarette smoke-induced chronic obstructive pulmonary disease. We demonstrate that aerobic conditioning had a protective effect in emphysema development induced by cigarette smoke exposure. This effect was most likely secondary to an effect of exercise on oxidant-antioxidant balance and anti-inflammatory mediators.

Immune Function: Impact of Exercise and Nutritional Interventions

This article provides a brief commentary on the accompanying article, "Nutrition and Physical Activity Interventions to Improve Immunity" by Davison, Kehaya, and Jones. The article reviews the evidence on physical exercise and/or nutrition in modulating immune response, with a specific focus on the prevention of respiratory infection. Given the large scope of the review, an overview of current findings is presented, rather than in-depth discussions, and the nutritional strategies discussed tend to focus on the strategies that have been studied in the context of exercise. Some further insight is provided in the commentary on potential mechanisms that may explain the benefits of exercise, a brief discussion on the impact of obesity and host defense, and future directions for research. In general, the article sufficiently describes the current evidence, and draws appropriate conclusions based on the evidence presented. The article is recommended for audiences that have limited background on these topics, and for those who are familiar with this line of research.

Update on the Mechanisms of Pulmonary Inflammation and Oxidative Imbalance Induced by Exercise

The mechanisms involved in the generation of oxidative damage and lung inflammation induced by physical exercise are described. Changes in lung function induced by exercise involve cooling of the airways, fluid evaporation of the epithelial surface, increased contact with polluting substances, and activation of the local and systemic inflammatory response. The present work includes evidence obtained from the different types of exercise in terms of duration and intensity, the effect of both acute performance and chronic performance, and the influence of special conditions such as cold weather, high altitude, and polluted environments. Levels of prooxidants, antioxidants, oxidative damage to biomolecules, and cellularity, as well as levels of soluble mediators of the inflammatory response and its effects on tissues, are described in samples of lung origin. These samples include tissue homogenates, induced sputum, bronchoalveolar lavage fluid, biopsies, and exhaled breath condensate obtained in experimental protocols conducted on animal and human models. Finally, the need to simultaneously explore the oxidative/inflammatory parameters to establish the interrelation between them is highlighted.

Inflammation and its genesis in cystic fibrosis

The host inflammatory response in cystic fibrosis (CF) lung disease has long been recognized as a central pathological feature and an important therapeutic target. Indeed, many believe that bronchiectasis results largely from the oxidative and proteolytic damage comprised within an exuberant airway inflammatory response that is dominated by neutrophils. In this review, we address the longstanding argument of whether or not the inflammatory response is directly attributable to impairment of the cystic fibrosis transmembrane conductance regulator or only secondary to airway obstruction and chronic bacterial infection and challenge the importance of this distinction in the context of therapy. We also review the centrality of neutrophils in CF lung pathophysiology and highlight more recent data that suggest the importance of other cell types and signaling beyond NF-κB activation. We discuss how protease and redox imbalance are critical factors in CF airway inflammation and end by reviewing some of the more promising therapeutic approaches now under development.