Montelukast, Leukotriene Inhibitor, Reduces LPS-Induced Acute Lung Inflammation and Human Neutrophil Activation.

OBJECTIVES: Some pro-inflammatory lipids derived from 1 lipooxygenase enzyme are potent neutrophil chemoattractant, a cell centrally involved in acute respiratory distress syndrome (ARDS); a syndrome lacking effective treatment. Considering the beneficial effects of the leukotriene receptor inhibitor, montelukast, on other lung diseases, whether montelukast attenuates inflammation in a mouse model of ARDS, and whether it reduces LPS stimulated activation of human neutrophils was investigated. METHODS: Thirty-five C57Bl/6 mice were distributed into control (PBS)+24h, LPS+24h (10µg/mouse), control+48h, LPS+48h, and LPS 48h+Montelukast (10mg/kg). In addition, human neutrophils were incubated with LPS (1µg/mL) and treated with montelukast (10µM). RESULTS: Oral-tracheal administration of montelukast significantly attenuated total cells (P<.05), macrophages (P<.05), neutrophils (P<.01), lymphocytes (P<.001) and total protein levels in BAL (P<.05), as well as IL-6 (P<.05), CXCL1/KC (P<.05), IL-17 (P<.05) and TNF-α (P<.05). Furthermore, montelukast reduced neutrophils (P<.001), lymphocytes (P<.01) and macrophages (P<.01) in the lung parenchyma. In addition, montelukast restored BAL VEGF levels (P<.05). LTB4 receptor expression (P<.001) as well as NF-κB (P<.001), a downstream target of LPS, were also reduced in lung parenchymal leukocytes. Furthermore, montelukast reduced IL-8 (P<.001) production by LPS-treated human neutrophils. CONCLUSION: In conclusion, montelukast efficiently attenuated both LPS-induced lung inflammation in a mouse model of ARDS and in LPS challenged human neutrophils.

Aerobic Exercise Protects from Pseudomonas aeruginosa-Induced Pneumonia in Elderly Mice.

BACKGROUND: Pseudomonas aeruginosa (PS) infection results in severe morbidity and mortality, especially in immune-deficient populations. Aerobic exercise (AE) modulates the immune system, but its effects on the outcomes of pulmonary PS infection in elderly mice are unknown. METHODS: BALB/c mice (24 weeks old) were randomized to sedentary, exercise (EX), PS, and PS + EX groups for the acute experimental setting, and PS and PS + EX groups for the chronic setting. Low-intensity AE was performed for 5 weeks, 60 min/day; 24 h after the final AE session, mice were inoculated with 5 × 104 colony-forming units (CFU) of PS, and 24 h and 14 days after PS inoculation, mice were studied. RESULTS: AE inhibited PS colonization (p < 0.001) and lung inflammation (total cells, neutrophils, lymphocytes [p < 0.01] in bronchoalveolar lavage [BAL]), with significant differences in BAL levels of IL-1ß (p < 0.001), IL-6 (p < 0.01), CXCL1 (p < 0.001), and TNF-α (p < 0.001), as well as parenchymal neutrophils (p < 0.001). AE increased BAL levels of IL-10 and parenchymal (p < 0.001) and epithelial (p < 0.001) IL-10 expression, while epithelial (p < 0.001) and parenchymal (p < 0.001) NF-κB expression was decreased. AE diminished pulmonary lipid peroxidation (p < 0.001) and increased glutathione peroxidase (p < 0.01). Pre-incubation of BEAS-2B with IL-10 inhibited PS-induced epithelial cell expression of TNF-α (p < 0.05), CD40 (p < 0.01), and dichlorodihydrofluorescein diacetate (p < 0.05). CONCLUSIONS: AE inhibits PS-induced lung inflammation and bacterial colonization in elderly mice, involving IL-10/NF-κB, and redox signaling.

Aerobic exercise inhibits obesity-induced respiratory phenotype.

PURPOSE: Obesity results in decreased lung function and increased inflammation. Moderate aerobic exercise (AE) reduced lung inflammation and remodeling in a variety of respiratory disease models. Therefore, this study investigated whether AE can attenuate a diet-induced obesity respiratory phenotype; including airway hyper-responsiveness (AHR), remodeling and inflammation. METHODS: Sixty C57Bl/6 male mice were distributed into four groups: control lean (CL), exercise lean (EL), obese (O) and obese exercise (OE) groups (2 sets of 7 and 8 mice per group; n = 15). A classical model of diet-induced obesity (DIO) over 12 weeks was used. AE was performed 60 min/day, 5 days/week for 5 weeks. Airway hyperresponsiveness (AHR), lung inflammation and remodeling, adipokines and cytokines in bronchoalveolar lavage (BAL) was determined. RESULTS: A high fat diet over 18 weeks significantly increased body weight (p < .0001). Five weeks of AE significantly reduced both AHR and pulmonary inflammation. AHR in obese mice that exercised was reduced at the basal level (p < .05), vehicle (PBS) (p < .05), 6.25 MCh mg/mL (p < .05), 12.5 MCh mg/mL (p < .01), 25 MCh mg/mL (p < .01) and 50 MCh mg/mL (p < .05). Collagen (p < .001) and elastic (p < .001) fiber deposition in airway wall and also smooth muscle thickness (p < .001) were reduced. The number of neutrophils (p < .001), macrophages (p < .001) and lymphocytes (p < .01) were reduced in the peribronchial space as well as in the BAL: lymphocytes (p < .01), macrophages (p < .01), neutrophils (p < .001). AE reduced obesity markers leptin (p < .001), IGF-1 (p < .01) and VEGF (p < .001), while increased adiponectin (p < .01) in BAL. AE also reduced pro-inflammatory cytokines in the BAL: IL-1ß (p < .001), IL-12p40 (p < .001), IL-13 (p < .01), IL-17 (p < .001, IL-23 (p < .05) and TNF-alpha (p < .05), and increased anti-inflammatory cytokine IL-10 (p < .05). CONCLUSIONS: Aerobic exercise reduces high fat diet-induced obese lung phenotype (AHR, pulmonary remodeling and inflammation), involving anti-inflammatory cytokine IL-10 and adiponectin.

Aerobic exercise inhibits acute lung injury: from mouse to human evidence Exercise reduced lung injury markers in mouse and in cells.

Acute respiratory distress syndrome (ARDS) is defined as hypoxemic respiratory failure with intense pulmonary inflammation, involving hyperactivation of endothelial cells and neutrophils. Given the anti-inflammatory effects of aerobic exercise (AE), this study investigated whether AE performed daily for 5 weeks would inhibit extra-pulmonary LPS-induced ARDS. C57Bl/6 mice were distributed into Control, Exercise, LPS and Exercise+LPS groups. AE was performed on a treadmill for 5x/week for four weeks before LPS administration. 24hours after the final AE physical test, animals received 100ug of LPS intra-peritoneally. In addition, whole blood cell culture, neutrophils and human endothelial cells were preincubated with IL-10, an anti-inflammatory cytokine induced by exercise. AE reduced total protein levels (p<0.01) and neutrophil accumulation in bronchoalveolar lavage (BAL) (p<0.01) and lung parenchyma (p<0.01). AE reduced BAL inflammatory cytokines IL-1ß, IL-6 and GM-CSF (p<0.001), CXCL1/KC, IL-17, TNF-alpha and IGF-1 (p<0.01). Systemically, AE reduced IL-1ß, IL-6 and IFN-gamma (p<0.001), CXCL1/KC (p<0.01) and TNF-alpha (p<0.05). AE increased IL-10 levels in serum (p<0.001) and BAL (p<0.001). Furthermore, AE increased superoxide dismutase SOD (p<0.01) and decreased superoxide anion accumulation in the lungs (p<0.01). Lastly, pre-incubation with IL-10 significantly reduced LPS-induced activation of whole blood cells, neutrophils and HUVECs, as observed by reduced production of IL-1ß, IL-6, IL-8 and TNF-alpha. Our data suggest that AE inhibited LPS-induced lung inflammation by attenuating inflammatory cytokines and oxidative stress markers in mice and human cell culture via enhanced IL-10 production.

Aerobic Exercise Attenuated Bleomycin-Induced Lung Fibrosis in Th2-Dominant Mice.

INTRODUCTION: The aim of this study was to investigate the effect of aerobic exercise (AE) in reducing bleomycin-induced fibrosis in mice of a Th2-dominant immune background (BALB/c). METHODS: BALB/c mice were distributed into: sedentary, control (CON), Exercise-only (EX), sedentary, bleomycin-treated (BLEO) and bleomycin-treated+exercised (BLEO+EX); (n = 8/group). Following treadmill adaptation, 15 days following a single, oro-tracheal administration of bleomycin (1.5U/kg), AE was performed 5 days/week, 60min/day for 4 weeks at moderate intensity (60% of maximum velocity reached during a physical test) and assessed for pulmonary inflammation and remodeling, and cytokine levels in bronchoalveolar lavage (BAL). RESULTS: At 45 days post injury, compared to BLEO, BLEO+EX demonstrated reduced collagen deposition in the airways (p<0.001) and also in the lung parenchyma (p<0.001). In BAL, a decreased number of total leukocytes (p<0.01), eosinophils (p<0.001), lymphocytes (p<0.01), macrophages (p<0.01), and neutrophils (p<0.01), as well as reduced pro-inflammatory cytokines (CXCL-1; p<0.01), (IL-1ß; p<0.001), (IL-5; p<0.01), (IL-6; p<0.001), (IL-13; p<0.01) and pro-fibrotic growth factor IGF-1 (p<0.001) were observed. Anti-inflammatory cytokine IL-10 was increased (p<0.001). CONCLUSION: AE attenuated bleomycin-induced collagen deposition, inflammation and cytokines accumulation in the lungs of mice with a predominately Th2-background suggesting that therapeutic AE (15-44 days post injury) attenuates the pro-inflammatory, Th2 immune response and fibrosis in the bleomycin model.

Aerobic Exercise Reduces Asthma Phenotype by Modulation of the Leukotriene Pathway.

INTRODUCTION: Leukotrienes (LTs) play a central role in asthma. Low- to moderate-intensity aerobic exercise (AE) reduces asthmatic inflammation in clinical studies and in experimental models. This study investigated whether AE attenuates LT pathway activation in an ovalbumin (OVA) model of asthma. METHODS: Sixty-four male, BALB/c mice were distributed into Control, Exercise (Exe), OVA, and OVA + Exe groups. Treadmill training was performed at moderate intensity, 5×/week, 1 h/session for 4 weeks. Quantification of bronchoalveolar lavage (BAL) cellularity, leukocytes, airway remodeling, interleukin (IL)-5, IL-13, cysteinyl leukotriene (CysLT), and leukotriene B4 (LTB4) in BAL was performed. In addition, quantitative analyses on peribronchial leukocytes and airway epithelium for LT pathway agents: 5-lypoxygenase (5-LO), LTA4 hydrolase (LTA4H), CysLT1 receptor, CysLT2 receptor, LTC4 synthase, and LTB4 receptor 2 (BLT2) were performed. Airway hyperresponsiveness (AHR) to methacholine (MCh) was assessed via whole body plethysmography. RESULTS: AE decreased eosinophils (p < 0.001), neutrophils (p > 0.001), lymphocytes (p < 0.001), and macrophages (p < 0.01) in BAL, as well as eosinophils (p < 0.01), lymphocytes (p < 0.001), and macrophages (p > 0.001) in airway walls. Collagen (p < 0.01), elastic fibers (p < 0.01), mucus production (p < 0.01), and smooth muscle thickness (p < 0.01), as well as IL-5 (p < 0.01), IL-13 (p < 0.01), CysLT (p < 0.01), and LTB4 (p < 0.01) in BAL were reduced. 5-LO (p < 0.05), LTA4H (p < 0.05), CysLT1 receptor (p < 0.001), CysLT2 receptor (p < 0.001), LTC4 synthase (p < 0.001), and BLT2 (p < 0.01) expression by peribronchial leukocytes and airway epithelium were reduced. Lastly, AHR to MCh 25 mg/mL (p < 0.05) and 50 mg/mL (p < 0.01) was reduced. CONCLUSION: Moderate-intensity AE attenuated asthma phenotype and LT production in both pulmonary leukocytes and airway epithelium of OVA-treated mice.

Dendritic Cells Are Involved in the Effects of Exercise in a Model of Asthma.

INTRODUCTION: This study investigated the effects of aerobic exercise (AE) on both the maturation of dendritic cells (DC) and the activation of lymphocytes in a mouse model of chronic allergic airway inflammation. METHODS: C57BL/6 mice distributed into control, exercise, ovalbumin (OVA), and OVA + exercise groups were submitted to OVA sensitization and challenge. Treadmill training was performed for 4 wk, and mice were assessed for classical features of chronic allergic airway inflammation as well as dendritic cell activation and T-lymphocyte response. RESULTS: AE reduced OVA-induced eosinophilic inflammation as observed in bronchoalveolar lavage fluid (P < 0.001), airway walls (P < 0001), and also reduced collagen deposition (P < 0.001). AE also reduced bronchoalveolar lavage fluid cytokines (interleukin [IL]-4, P < 0.001; IL-5, P < 0.01; IL-6, P < 0.001; IL-13, P < 0.01; and tumor necrosis factor α, P < 0.01). Cells derived from mediastinal lymphnodes of AE animals that were restimulated with OVA produced less IL-4 (P < 0.01), IL-5 (P < 0.01), and IL-13 (P < 0.001). In addition, AE reduced both DC activation, as demonstrated by reduced release of IL-6 (P < 0.001), CXCL1/KC (P < 0.01), IL-12p70 (P < 0.01), and tumor necrosis factor α (P < 0.05) and DC maturation, as demonstrated by lower MCH-II expression (P < 0.001). CONCLUSION: AE attenuated dendritic cell and lymphocyte activation and maturation, which contributed to reduced airway inflammation and remodeling in the OVA model of chronic allergic airway inflammation.