A Plant Proteinase Inhibitor from Enterolobium contortisiliquum Attenuates Pulmonary Mechanics, Inflammation and Remodeling Induced by Elastase in Mice.

Proteinase inhibitors have been associated with anti-inflammatory and antioxidant activities and may represent a potential therapeutic treatment for emphysema. Our aim was to evaluate the effects of a plant Kunitz proteinase inhibitor, Enterolobium contortisiliquum trypsin inhibitor (EcTI), on several aspects of experimental elastase-induced pulmonary inflammation in mice. C57/Bl6 mice were intratracheally administered elastase (ELA) or saline (SAL) and were treated intraperitoneally with EcTI (ELA-EcTI, SAL-EcTI) on days 1, 14 and 21. On day 28, pulmonary mechanics, exhaled nitric oxide (ENO) and number leucocytes in the bronchoalveolar lavage fluid (BALF) were evaluated. Subsequently, lung immunohistochemical staining was submitted to morphometry. EcTI treatment reduced responses of the mechanical respiratory system, number of cells in the BALF, and reduced tumor necrosis factor-α (TNF-α), matrix metalloproteinase-9 (MMP-9), matrix metalloproteinase-12 (MMP-12), tissue inhibitor of matrix metalloproteinase (TIMP-1), endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS)-positive cells and volume proportion of isoprostane, collagen and elastic fibers in the airways and alveolar walls compared with the ELA group. EcTI treatment reduced elastase induced pulmonary inflammation, remodeling, oxidative stress and mechanical alterations, suggesting that this inhibitor may be a potential therapeutic tool for chronic obstructive pulmonary disease (COPD) management.

Modulation of the oscillatory mechanics of lung tissue and the oxidative stress response induced by arginase inhibition in a chronic allergic inflammation model.

BACKGROUND: The importance of the lung parenchyma in the pathophysiology of asthma has previously been demonstrated. Considering that nitric oxide synthases (NOS) and arginases compete for the same substrate, it is worthwhile to elucidate the effects of complex NOS-arginase dysfunction in the pathophysiology of asthma, particularly, related to distal lung tissue. We evaluated the effects of arginase and iNOS inhibition on distal lung mechanics and oxidative stress pathway activation in a model of chronic pulmonary allergic inflammation in guinea pigs. METHODS: Guinea pigs were exposed to repeated ovalbumin inhalations (twice a week for 4 weeks). The animals received 1400 W (an iNOS-specific inhibitor) for 4 days beginning at the last inhalation. Afterwards, the animals were anesthetized and exsanguinated; then, a slice of the distal lung was evaluated by oscillatory mechanics, and an arginase inhibitor (nor-NOHA) or vehicle was infused in a Krebs solution bath. Tissue resistance (Rt) and elastance (Et) were assessed before and after ovalbumin challenge (0.1%), and lung strips were submitted to histopathological studies. RESULTS: Ovalbumin-exposed animals presented an increase in the maximal Rt and Et responses after antigen challenge (p<0.001), in the number of iNOS positive cells (p<0.001) and in the expression of arginase 2, 8-isoprostane and NF-kB (p<0.001) in distal lung tissue. The 1400 W administration reduced all these responses (p<0.001) in alveolar septa. Ovalbumin-exposed animals that received nor-NOHA had a reduction of Rt, Et after antigen challenge, iNOS positive cells and 8-isoprostane and NF-kB (p<0.001) in lung tissue. The activity of arginase 2 was reduced only in the groups treated with nor-NOHA (p <0.05). There was a reduction of 8-isoprostane expression in OVA-NOR-W compared to OVA-NOR (p<0.001). CONCLUSIONS: In this experimental model, increased arginase content and iNOS-positive cells were associated with the constriction of distal lung parenchyma. This functional alteration may be due to a high expression of 8-isoprostane, which had a procontractile effect. The mechanism involved in this response is likely related to the modulation of NF-kB expression, which contributed to the activation of the arginase and iNOS pathways. The association of both inhibitors potentiated the reduction of 8-isoprostane expression in this animal model.

Aerobic exercise training engages cholinergic signaling to improve emphysema induced by cigarette smoke exposure in mice.

Lung inflammation is modulated by cholinergic signaling and exercise training protects mice against pulmonary emphysema development; however, whether exercise training engages cholinergic signaling is unknown. AIMS: As cholinergic signaling is directly linked to the vesicular acetylcholine transporter (VAChT) levels, we evaluated whether the effects of aerobic exercise training depend on the VAChT levels in mice with pulmonary emphysema. MAIN METHODS: Wild-type (WT) and mutant (KDHOM) mice (65-70% of reduction in VAChT levels) were exposed to cigarette smoke (30 min, 2×/day, 5×/week, 12 weeks) and submitted or not to aerobic exercise training on a treadmill (60 min/day, 5×/week, 12 weeks). Lung function and inflammation were evaluated. KEY FINDINGS: Cigarette smoke reduced body mass in mice (p < 0.001) and increased alveolar diameter (p < 0.001), inflammation (p < 0.001) and collagen deposition (p < 0.01) in lung tissue. Both trained groups improved their performance in the final physical test compared to the initial test (p < 0.001). In WT mice, exercise training protected against emphysema development (p < 0.05), reduced mononuclear cells infiltrate (p < 0.001) and increased MAC-2 positive cells in lung parenchyma (p < 0.05); however, these effects were not observed in KDHOM mice. The exercise training reduced iNOS-positive cells (p < 0.001) and collagen fibers deposition (p < 0.05) in lung parenchyma of WT and KDHOM mice, although KDHOM mice showed higher levels of iNOS-positive cells. SIGNIFICANCE: Our data suggest that the protective effects of aerobic exercise training on pulmonary emphysema are, at least in part, dependent on the integrity of the lung cholinergic signaling.

Sakuranetin reverses vascular peribronchial and lung parenchyma remodeling in a murine model of chronic allergic pulmonary inflammation.

BACKGROUND AND PURPOSE: Asthma is a disease of high prevalence and morbidity that generates high costs in hospitalization and treatment. Although the airway is involved in the physiopathology of asthma, there is also evidence of the importance of vascular and lung parenchyma inflammation and remodeling, which can contribute to the functional pulmonary alterations observed in asthmatic patients. Our aim was to evaluate treatment using sakuranetin, a flavone isolated from the twigs of Baccharis retusa (Asteraceae), on vascular and lung parenchyma alterations in an experimental murine model of asthma. METHODS: Male BALB/c mice were subjected to a sensitization protocol with ovalbumin for 30days and were treated with or without sakuranetin (20mg/kg/mice) or dexamethasone (5mg/kg/mice); then, the lungs were collected for histopathological analysis. We evaluated extracellular matrix remodeling (collagen and elastic fibers), inflammation (eosinophils and NF-kB) and oxidative stress (8-isoprostane) in the pulmonary vessels and lung parenchyma. The thickness of the vascular wall was quantified, as well as the vascular endothelial growth factor (VEGF) levels. RESULTS: We demonstrated that sakuranetin reduced the number of eosinophils and elastic fibers in both the pulmonary vessels and the lung parenchyma, probably due to a reduction of oxidative stress and of the transcription factor NF-kB and VEGF levels in the lung. In addition, it reduced the thickness of the pulmonary vascular wall. The treatment had no effect on the collagen fibers. In most of the parameters, the effect of sakuranetin was similar to the dexamethasone effect. CONCLUSIONS AND IMPLICATIONS: Sakuranetin had anti-inflammatory and antioxidant effects, preventing vascular and distal parenchyma changes in this experimental model of asthma.

Efeito da redução da função colinérgica na mecânica pulmonar e na histopatologia pulmonar em modelo experimental de inflamação aguda induzida por instilação de LPS em camundongos geneticamente modificados / Cholinergic function reduction effect of pulmonary mechanics and pulmonary histopathology acute inflammation model of experimental induced by LPS in mice genetically modified

A lesão pulmonar aguda (LPA) é caracterizada por inflamação pulmonar de início súbito com recrutamento de polimorfonucleares e liberação de mediadores próinflamatórios. É uma condição grave que evolui com óbito em aproximadamente 40% dos casos. Diversos estudos que elucidaram a fisiopatologia da LPA, o tratamento ainda é insatisfatório. O sistema colinérgico anti-inflamatório foi descrito no pulmão e está relacionado a um reflexo via nervo vago que inibe a liberação de citocinas inflamatórias por efeitos relacionados a ação da acetilcolina em receptores nicotínicos. Nossa hipótese é de que a redução de VAChT, que está relacionada ao déficit na liberação de ACh, module a resposta inflamatória pulmonar em modelo de LPS. Objetivo: 1. Avaliar se a deficiência de VAChT modula a resposta pulmonar em animais geneticamente modificados; 2. Avaliar se a deficiência colinérgica induzida por redução de VAChT está envolvida na resposta pulmonar ao LPS e elucidar alguns mecanismos envolvidos; 3. Avaliar o potencial terapêutico do PNU, um agonista de alfa7nAChR nas alterações funcionais e histopatológicas em modelo de LPA em animais C57Bl6. Metodologia: Foram utilizados camundongos machos geneticamente modificados mutante (VAChT KDHOM) ou selvagem (WT) e C57BL/6. Inicialmente avaliamos a função pulmonar e a histopatologia pulmonar em animais VAChT KDHOM. Após, animais WT e VAChT KDHOM receberam instilação intranasal de LPS ou salina e a resposta inflamatória foi avaliada de 1,5h até 72 horas após. Ainda, foi avaliado a resposta pulmonar em VAChT KDHOM e WT após a instilação de LPS intraperitoneal. Por fim, animais C57BL/6 instilados com LPS intranasal, receberam tratamento prévio ou após com PNU, agonista do receptor nicotínico alfa7. Resultados: Animais mutante apresentaram maior quantidade de células recuperadas no lavado bronco alveolar (LBA) e aumento de citocinas próinflamatórias, aumento de edema peribrônquico e piora da função pulmonar. Ainda,...

Acute lung injury (ALI) is characterized by acute lung inflammation with recruitment of polymorphonuclear and release of proinflammatory mediators. It is a severe condition since leads to death 40% of the cases. Several studies have elucidated the pathophysiology of ALI, however the treatment is still unsatisfactory. The anti-inflammatory cholinergic system was described in the lung and is related to a vagal nerve reflex that inhibits the release of inflammatory cytokines by the action o ACh on nicotinic receptors. Our hypothesis is that the VAChT reduction, which is related to the deficit in the release of ACh, modulates the pulmonary inflammatory response in a model of LPS. Aim: 1. To assess whether VAChT deficiency modulates the pulmonary response in genetically modified animals; 2. Assess whether cholinergic deficiency induced reduction VAChT is involved in pulmonary response to LPS and elucidate some mechanisms involved; 3. To evaluate the therapeutic potential of PNU, an agonist alfa7nAChR, in functional and histological changes in C57BL6 mice with LPA. Methods: Mutant genetically modified male mice (VAChT KDHOM) or wild (WT) and C57BL/6 were used. First, we evaluated lung function and lung histopathology in VAChT KDHOM animals. After, WT animals and VAChT KDHOM received intranasal instillation of LPS or saline and the inflammatory response was assessed 1.5 hours to 72 hours. Moreover, the pulmonary response was evaluated in WT and VAChT KDHOM after instillation of LPS intraperitoneally. Finally, C57BL6 instilled with intranasal LPS received prior or post-treatment with PNU, an alfa7 nicotinic receptor agonist. Results: Mutant animals had higher number of cells recovered in brochoalveolar lavage (BAL) and increased pro-inflammatory cytokines, peribronchial edema and worsening of lung function. Still, there was an increase of NF_kB expression and reduction of JAK2. The VAChT deficiency induced increase in inflammatory cells...