Functional alterations of alveolar macrophages subjected to smoke exposure and antioxidant lazaroids

Mechanisms, Pathophysiology and Currently Proposed Treatments of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is one of the leading global causes of morbidity and mortality. A hallmark of COPD is progressive airflow obstruction primarily caused by cigarette smoke (CS). CS exposure causes an imbalance favoring pro- over antioxidants (oxidative stress), leading to transcription factor activation and increased expression of inflammatory mediators and proteases. Different cell types, including macrophages, epithelial cells, neutrophils, and T lymphocytes, contribute to COPD pathophysiology. Alteration in cell functions results in the generation of an oxidative and inflammatory microenvironment, which contributes to disease progression. Current treatments include inhaled corticosteroids and bronchodilator therapy. However, these therapies do not effectively halt disease progression. Due to the complexity of its pathophysiology, and the risk of exacerbating symptoms with existing therapies, other specific and effective treatment options are required. Therapies directly or indirectly targeting the oxidative imbalance may be promising alternatives. This review briefly discusses COPD pathophysiology, and provides an update on the development and clinical testing of novel COPD treatments.

Pediatric inhalation injury

Smoke inhalation injury can cause severe physiologic perturbations. In pediatric patients, these perturbations cause profound changes in cardiac and pulmonary physiology. In this review, we examine the pathology, early management options, ventilator strategy, and long-term outcomes in pediatric patients who have suffered a smoke inhalation injury.

Antioxidant pharmacological therapies for COPD

Increased oxidative stress occurs in the lungs and systemically in COPD, which plays a role in many of the pathogenic mechanisms in COPD. Hence, targeting local lung and systemic oxidative stress with agents that modulate the antioxidants/redox system or boost endogenous antioxidants would be a useful therapeutic approach in COPD. Thiol antioxidants (N-acetyl-l-cysteine [NAC] and N-acystelyn, carbocysteine, erdosteine, and fudosteine) have been used to increase lung thiol content. Modulation of cigarette smoke (CS) induced oxidative stress and its consequent cellular changes have also been reported to be effected by synthetic molecules, such as spin traps (α-phenyl-N-tert-butyl nitrone), catalytic antioxidants (superoxide dismutase [ECSOD] mimetics), porphyrins, and lipid peroxidation and protein carbonylation blockers/inhibitors (edaravone and lazaroids/tirilazad). Preclinical and clinical trials have shown that these antioxidants can reduce oxidative stress, affect redox and glutathione biosynthesis genes, and proinflammatory gene expression. In this review the approaches to enhance lung antioxidants in COPD and the potential beneficial effects of antioxidant therapy on the course of the disease are discussed.

Pharmacological antioxidant strategies as therapeutic interventions for COPD

Cigarette/tobacco smoke/biomass fuel-induced oxidative and aldehyde/carbonyl stress are intimately associated with the progression and exacerbation of chronic obstructive pulmonary disease (COPD). Therefore, targeting systemic and local oxidative stress with antioxidants/redox modulating agents, or boosting the endogenous levels of antioxidants are likely to have beneficial effects in the treatment/management of COPD. Various antioxidant agents, such as thiol molecules (glutathione and mucolytic drugs, such as N-acetyl-L-cysteine and N-acystelyn, erdosteine, fudosteine, ergothioneine, and carbocysteine), have been reported to modulate various cellular and biochemical aspects of COPD. These antioxidants have been found to scavenge and detoxify free radicals and oxidants, regulate of glutathione biosynthesis, control nuclear factor-kappaB (NF-kappaB) activation, and hence inhibiting inflammatory gene expression. Synthetic molecules, such as specific spin traps like α-phenyl-N-tert-butyl nitrone, a catalytic antioxidant (ECSOD mimetic), porphyrins (AEOL 10150 and AEOL 10113), and a superoxide dismutase mimetic M40419, iNOS and myeloperoxidase inhibitors, lipid peroxidation inhibitors/blockers edaravone, and lazaroids/tirilazad have also been shown to have beneficial effects by inhibiting cigarette smoke-induced inflammatory responses and other carbonyl/oxidative stress-induced cellular alterations. A variety of oxidants, free radicals, and carbonyls/aldehydes are implicated in the pathogenesis of COPD, it is therefore, possible that therapeutic administration or supplementation of multiple antioxidants and/or boosting the endogenous levels of antioxidants will be beneficial in the treatment of COPD. This review discusses various novel pharmacological approaches adopted to enhance lung antioxidant levels, and various emerging beneficial and/or prophylactic effects of antioxidant therapeutics in halting or intervening the progression of COPD. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.

Macrophage phagocytosis: effects of environmental pollutants, alcohol, cigarette smoke, and other external factors

The ability of a pathogen to evade host immunity successfully, in contrast to the host's capacity to defend itself against a foreign invader, is a complex struggle, in which eradication of infection is dictated by a robust immunologic response. Often, there are external factors that can alter the outcome by tipping the scale to benefit pathogen establishment rather than resolution by the host's defense system. These external sources, such a cigarettes, alcohol, or environmental pollutants, can negatively influence the effectiveness of the immune system's response to a pathogen. The observed suppression of immune function can be attributed to dysregulated cytokine and chemokine production, the loss of migratory potential, or the inability to phagocytose pathogens by immune cells. This review will focus on the mechanisms involved during the toxin-induced suppression of phagocytosis. The accumulated data support the importance of studying the mechanisms of phagocytosis following exposure to these factors, in that this effect alone cannot only leave the host susceptible to infection but also promote alterations in many other macrophage functions necessary for pathogen clearance and restoration of homeostasis.

Análise do lavado broncoalveolar em vítimas de queimaduras faciais graves

OBJETIVO: Analisar o lavado broncoalveolar (LBA) de vítimas de queimaduras que inalaram fumaça a fim de identificar alterações que possam estar associadas à morte ou à sobrevida. MÉTODOS: Dezoito vítimas de queimaduras faciais foram submetidas a LBA até 24 h após o evento, sendo realizadas a análise do conteúdo celular e proteico, incluindo TNF-α, HLA-DR, CD14, CD68 e iNOS. RESULTADOS: Dos 18 pacientes submetidos à broncoscopia, 8 (44,4%) morreram durante o seguimento. A média de idade dos pacientes que morreram foi significativamente maior (44,7 vs. 31,5 anos). A superfície corporal queimada foi em média de 60,1% nos pacientes que morreram e de 26,1% nos sobreviventes (p < 0,0001). Entre os 18 pacientes submetidos à broncoscopia, 11 (61,1%) apresentaram sinais endoscópicos de lesão por inalação de fumaça, e 4 (36,4%) destes faleceram. Dos 7 pacientes sem sinais de lesão por inalação de fumaça, 4 (57,1%) faleceram. A média do número de células epiteliais ciliadas no LBA dos pacientes que morreram foi significativamente maior daquela dos sobreviventes (6,6% vs. 1,4%; p = 0,03). Os demais parâmetros analisados não mostraram diferença entre os grupos. CONCLUSÕES: A superfície corporal queimada mostrou ser um fator preditivo de mortalidade. O aumento do número de células epiteliais ciliadas no LBA, denotando descamação epitelial brônquica, esteve associado à maior mortalidade de pacientes com queimaduras faciais.

Airway inflammation contributes to health status in COPD: a cross-sectional study

Background

Chronic obstructive pulmonary disease (COPD) is characterized by irreversible airflow limitation and airway inflammation, accompanied by decreased health status. It is still unknown which factors are responsible for the impaired health status in COPD. We postulated that airway inflammation negatively contributes to health status in COPD.

Methods

In 114 COPD patients (99 male, age: 62 ± 8 yr, 41 [31–55] pack-years, no inhaled or oral corticosteroids, postbronchodilator FEV₁: 63 ± 9% pred, FEV₁/IVC: 48 ± 9%) we obtained induced sputum and measured health status (St. George's respiratory questionnaire (SGRQ)), postbronchodilator FEV₁, hyperinflation (RV/TLC), and airway hyperresponsiveness to methacholine (PC₂₀). Sputum was induced by hypertonic saline and differential cell counts were obtained in 102 patients.

Results

Univariate analysis showed that SGRQ total and symptom score were positively associated with % sputum macrophages (r = 0.20, p = 0.05; and r = 0.20, p = 0.04, respectively). Multiple regression analysis confirmed these relationships, providing significant contributions of % sputum macrophages (B = 0.25, p = 0.021) and RV/TLC (B = 0.60, p = 0.002) to SGRQ total score. Furthermore, SGRQ symptom score was associated with % sputum macrophages (B = 0.30, p = 0.03) and RV/TLC (B = 0.48, p = 0.044), whilst SGRQ activity score was associated with % sputum macrophages (B = 0.46, p = 0.002), RV/TLC (B = 0.61, p = 0.015), and PC₂₀ (B = -9.3, p = 0.024). Current smoking and FEV₁ were not significantly associated with health status in the multiple regression analysis.

Conclusion

We conclude that worse health status in COPD patients is associated with higher inflammatory cell counts in induced sputum. Our findings suggest that airway inflammation and hyperinflation independently contribute to impaired health status in COPD. This may provide a rationale for anti-inflammatory therapy in this disease.

Substance P and neutral endopeptidase in development of acute respiratory distress syndrome following fire smoke inhalation

To characterize the tachykininergic effects in fire smoke (FS)-induced acute respiratory distress syndrome (ARDS), we designed a series of studies in rats. Initially, 20 min of FS inhalation induced a significant increase of substance P (SP) in bronchoalveolar lavage fluid (BALF) at 1 h and persisted for 24 h after insult. Conversely, FS disrupted 51.4, 55.6, 46.3, and 43.0% enzymatic activity of neutral endopeptidase (NEP, a primary hydrolyzing enzyme for SP) 1, 6, 12, and 24 h after insult, respectively. Immunolabeling density of NEP in the airway epithelium largely disappeared 1 h after insult due to acute cell damage and shedding. These changes were also accompanied by extensive influx of albumin and granulocytes/lymphocytes in BALF. Furthermore, levels of BALF SP and tissue NEP activity dose dependently increased and decreased, respectively, following 0, low (10 min), and high (20 min) levels of FS inhalation. However, neither the time-course nor the dose-response study observed a significant change in the highest affinity neurokinin-1 receptor (NK-1R) for SP. Finally, treatment (10 mg/kg im) with SR-140333B, an NK-1R antagonist, significantly prevented 20-min FS-induced hypoxemia and pulmonary edema 24 h after insult. Further examination indicated that SR-140333B (1.0 or 10.0 mg/kg im) fully abolished early (1 h) plasma extravasation following FS. Collectively, these findings suggest that a combination of sustained SP and NEP inactivity induces an exaggerated neurogenic inflammation mediated by NK-1R, which may lead to an uncontrolled influx of protein-rich edema fluid and cells into the alveoli as a consequence of increased vascular permeability.

Age-related differences in pulmonary inflammatory responses to JP-8 jet fuel aerosol inhalation

Our previous studies have demonstrated that JP-8 jet fuel aerosol inhalation induced lung injury and dysfunction. To further examine JP-8 jet fuel-induced inflammatory mechanisms, a total of 40 male C57BL/6 mice (young, 3.5 months; adult, 12 months; half in each age group) were randomly assigned to the exposure or control groups. Mice were nose-only exposed to room air or atmospheres of 1000 mg/m3 JP-8 jet fuel for 1 h/day for 7 days. Lung injury was assessed by pulmonary mechanics, respiratory permeability, lavaged cell profile, and chemical mediators in bronchoalveolar lavage fluid (BALF). The young and adult mice exposed to JP-8 jet fuel had similar values with regards to increased lung dynamic compliance, lung permeability, BALF cell count, and decreased PGE2. However, there were several different responses between the young-versus-adult mice with respect to BALF cell differential, TNF-alpha, and 8-iso-PGF2,, levels after exposure to JP-8 jet fuel. These data suggest that JP-8 jet fuel may have different inflammatory mechanisms leading to lung injury and dysfunction in the younger-versus-adult mice.