The activity of cytochrome oxidase is increased in circulating lymphocytes of patients with chronic obstructive pulmonary disease, asthma, and chronic arthritis

Effect of Cigarette Smoke on Gut Microbiota: State of Knowledge

Cigarette smoke is a representative source of toxic chemical exposures to humans, and the adverse consequences of cigarette smoking are mediated by its effect on both neuronal and immune-inflammatory systems. Cigarette smoking also is a major risk factor for intestinal disorders, such as Crohn's disease and peptic ulcer. On the other hand, cigarette smoking is protective against developing ulcerative colitis. The effects of cigarette smoking on intestinal disorders include changes in intestinal irrigation and microbiome, increases in permeability of the mucosa, and impaired mucosal immune responses. However, the underlying mechanism linking cigarette smoking with intestinal microbiota dysbiosis is largely unknown. In this communication, we first review the current knowledge about the mechanistic interaction between cigarette smoke and intestinal microbiota dysbiosis, which include the likely actions of nicotine, aldehydes, polycyclic aromatic hydrocarbons, heavy metals, volatile organic compounds and toxic gases, and then reveal the potential mechanisms of the lung-gut cross talk and skin-gut cross talk in regulating the balance of intestinal microbiota and the interrelation of intestinal microbiota dysbiosis and systemic disorders.

Does gallic acid improve cardiac function by attenuation of oxidative stress and inflammation in an elastase-induced lung injury?

Objective(s):

Cardiovascular disease has an important role in mortality caused by lung injury. Emphysema is associated with impaired pulmonary gas exchange efficiency and airflow limitation associated with small airway inflammation. The aim was to evaluate the interactions between lung injury, inflammation, and cardiovascular disease. Since gallic acid has antioxidant and anti-inflammatory effects, we hypothesized that gallic acid protects the lung and the related heart dysfunction in elastase-induced lung injury.

Materials and Methods:

Forty-eight Sprague-Dawley male rats were randomly divided into six groups: Control, Porcine pancreatic elastase (PPE) , PPE+GA, and 3 groups for different doses of gallic acid (GA 7.5, GA 15, GA 30 mg/kg). PPE was injected intra-tracheally on days 1 and 10 of the test. In each group, electrocardiography, hemodynamic parameters, oxidative stress, and bronchoalveolar lavage fluid were examined.

Results:

PPE administration showed a decrease in HR and QRS voltage of electrocardiogram parameters, as well as in hemodynamic parameters (P<0.05, P<0.01, and P<0.001) and superoxide dismutase (SOD) (P<0.05). Tumor Necrosis Factor α (TNF-α) (P<0.001), interleukin 6 (IL-6) (P<0.001), interleukin 6 (MDA) (P<0.001), and the total number of white blood cells (P<0.001) showed an increase in PPE groups. Gallic acid preserved the values of hemodynamic properties, oxidative stress, inflammation, and electrocardiogram parameters in comparison to the PPE group.

Conclusion:

Briefly, this study showed the valuable effect of gallic acid in cardiac dysfunction related to elastase-induced lung injury. These findings suggested that gallic acid, as a natural antioxidant, has a potential therapeutic effect on preventing oxidative stress, inflammation, and subsequent cardiovascular disease.

Inflammatory bowel diseases, chronic liver diseases and the lung

This review is devoted to the distinct associations of inflammatory bowel diseases (IBD) and chronic liver disorders with chronic airway diseases, namely chronic obstructive pulmonary disease and bronchial asthma, and other chronic respiratory disorders in the adult population. While there is strong evidence for the association of chronic airway diseases with IBD, the data are much weaker for the interplay between lung and liver multimorbidities. The association of IBD, encompassing Crohn's disease and ulcerative colitis, with pulmonary disorders is underlined by their heterogeneous respiratory manifestations and impact on chronic airway diseases. The potential relationship between the two most prevalent liver-induced pulmonary vascular entities, i.e. portopulmonary hypertension and hepatopulmonary syndrome, and also between liver disease and other chronic respiratory diseases is also approached. Abnormal lung function tests in liver diseases are described and the role of increased serum bilirubin levels on chronic respiratory problems are considered.

Muscle dysfunction in chronic obstructive pulmonary disease: update on causes and biological findings

Respiratory and/or limb muscle dysfunction, which are frequently observed in chronic obstructive pulmonary disease (COPD) patients, contribute to their disease prognosis irrespective of the lung function. Muscle dysfunction is caused by the interaction of local and systemic factors. The key deleterious etiologic factors are pulmonary hyperinflation for the respiratory muscles and deconditioning secondary to reduced physical activity for limb muscles. Nonetheless, cigarette smoke, systemic inflammation, nutritional abnormalities, exercise, exacerbations, anabolic insufficiency, drugs and comorbidities also seem to play a relevant role. All these factors modify the phenotype of the muscles, through the induction of several biological phenomena in patients with COPD. While respiratory muscles improve their aerobic phenotype (percentage of oxidative fibers, capillarization, mitochondrial density, enzyme activity in the aerobic pathways, etc.), limb muscles exhibit the opposite phenotype. In addition, both muscle groups show oxidative stress, signs of damage and epigenetic changes. However, fiber atrophy, increased number of inflammatory cells, altered regenerative capacity; signs of apoptosis and autophagy, and an imbalance between protein synthesis and breakdown are rather characteristic features of the limb muscles, mostly in patients with reduced body weight. Despite that significant progress has been achieved in the last decades, full elucidation of the specific roles of the target biological mechanisms involved in COPD muscle dysfunction is still required. Such an achievement will be crucial to adequately tackle with this relevant clinical problem of COPD patients in the near-future.

Respiratory diseases and muscle dysfunction

Many respiratory diseases lead to impaired function of skeletal muscles, influencing quality of life and patient survival. Dysfunction of both respiratory and limb muscles in chronic obstructive pulmonary disease has been studied in depth, and seems to be caused by the complex interaction of general (inflammation, impaired gas exchange, malnutrition, comorbidity, drugs) and local factors (changes in respiratory mechanics and muscle activity, and molecular events). Some of these factors are also present in cystic fibrosis and asthma. In obstructive sleep apnea syndrome, repeated exposure to hypoxia and the absence of reparative rest are believed to be the main causes of muscle dysfunction. Deconditioning appears to be crucial for the functional impairment observed in scoliosis. Finally, cachexia seems to be the main mechanism of muscle dysfunction in advanced lung cancer. A multidimensional therapeutic approach is recommended, including pulmonary rehabilitation, an adequate level of physical activity, ventilatory support and nutritional interventions.

Anti-inflammatory Effect of Triterpenoic Acids of Eriobotrya japonica (Thunb.) Lindl. Leaf on Rat Model of Chronic Bronchitis

This study was designed to investigate the anti-inflammatory effect of Triterpenoic Acids from Eriobotrya japonica (Thunb.) Lindl. (TAL) on chronic bronchitis (CB) in rats. CB model was established by combination of Bacillus Calmette-Guerin (BCG, 5 mg/kg, injected through the caudal vein) and lipopolysaccharide (LPS, 1 g/L, injected through endotracheal intubation). Rats with CB model were treated with TAL (50, 150 and 450 mg/kg) for 3 weeks. The leukocytes in bronchoalveolar lavage fluid (BALF) were counted after Wright staining, the levels of cytokine tumor necrosis factor alpha (TNF-α), interleukin (IL)-8, and IL-10 in the supernatants of lung homogenate were assessed by enzyme-linked immunosorbent assay (ELISA), and the protein expression of nuclear factor kappaB (NF-κB) and intercellular adhesion molecule-1 (ICAM-1) on bronchial epithelium were tested by immunohistochemical staining. As compared to the normal and sham groups, the total number of leukocyte, the differential counts of neutrophils and alveolar macrophage (AM) in BALF, the levels of TNF-α and IL-8 in the supernatants of lung homogenate, and the expression of NF-κB and ICAM-1 on bronchial epithelium in CB rats were significantly increased, while the level of IL-10 was decreased. TAL (50, 150 and 450 mg/kg) attenuated these alterations in model CB rats, which indicates that TAL has anti-inflammatory effect in the rats with CB.

Pulmonary-intestinal cross-talk in mucosal inflammatory disease

Chronic obstructive pulmonary disease (COPD) and inflammatory bowel diseases (IBDs) are chronic inflammatory diseases of mucosal tissues that affect the respiratory and gastrointestinal tracts, respectively. They share many similarities in epidemiological and clinical characteristics, as well as in inflammatory pathologies. Importantly, both conditions are accompanied by systemic comorbidities that are largely overlooked in both basic and clinical research. Therefore, consideration of these complications may maximize the efficacy of prevention and treatment approaches. Here, we examine both the intestinal involvement in COPD and the pulmonary manifestations of IBD. We also review the evidence for inflammatory organ cross-talk that may drive these associations, and discuss the current frontiers of research into these issues.

Expressão das metaloproteinases da matriz 2 e 9 na saliva de pacientes com doença pulmonar obstrutiva crônica

O aumento da expressão das metaloproteinases da matriz extracelular (MPM) é considerado um importante fator no desenvolvimento da doença pulmonar obstrutiva crônica (DPOC). O presente estudo teve como objetivo avaliar os níveis de expressão da MPM-2 e MPM-9 na saliva de pacientes com DPOC em comparação com indivíduos saudáveis, verificando a viabilidade de usar a saliva para a caracterização de biomarcadores específicos em DPOC. Foram selecionados pacientes com DPOC (n=16) e controles saudáveis (n=9). Em ambos os grupos foram realizados teste espirométrico e obtidas amostras de saliva de cada indivíduo. Os níveis de MPM-2 e MPM-9 na saliva foram determinados pela técnica Western blot. A MPM-2 e a MPM-9 foram significativamente maiores em pacientes com DPOC do que no grupo de indivíduos saudáveis. Foi encontrada moderada correlação negativa entre a concentração de MPM-2 e o volume expiratório forçado no primeiro segundo (r= -0,582, p=0,014) em pacientes com DPOC. Estes resultados abrem novas perspectivas para o estudo específico de biomarcadores na saliva para predizer e monitorar a obstrução ao fluxo aéreo em pacientes com DPOC.

Chronic obstructive pulmonary disease and obstructive sleep apnea: overlaps in pathophysiology, systemic inflammation, and cardiovascular disease

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea syndrome represent two of the most prevalent chronic respiratory disorders in clinical practice, and cardiovascular diseases represent a major comorbidity in each disorder. The two disorders coexist (overlap syndrome) in approximately 1% of adults but asymptomatic lower airway obstruction together with sleep-disordered breathing is more prevalent. Although obstructive sleep apnea syndrome has similar prevalence in COPD as the general population, and vice versa, factors such as body mass index and smoking influence relationships. Nocturnal oxygen desaturation develops in COPD, independent of apnea/hypopnea, and is more severe in the overlap syndrome, thus predisposing to pulmonary hypertension. Furthermore, upper airway flow limitation contributes to nocturnal desaturation in COPD without apnea/hypopnea. Evidence of systemic inflammation in COPD and sleep apnea, involving C-reactive protein and IL-6, in addition to nuclear factor-kappaB-dependent pathways involving tumor necrosis factor-alpha and IL-8, provides insight into potential basic interactions between both disorders. Furthermore, oxidative stress develops in each disorder, in addition to activation and/or dysfunction of circulating leukocytes. These findings are clinically relevant because systemic inflammation may contribute to the pathogenesis of cardiovascular diseases and the cell/molecular pathways involved are similar to those identified in COPD and sleep apnea. However, the pathophysiological and clinical significance of systemic inflammation in COPD and sleep apnea is not proven, and thus, studies of patients with the overlap syndrome should provide insight into the mechanisms of systemic inflammation in COPD and sleep apnea, in addition to potential relationships with cardiovascular disease.

Advances in therapy for adult asthma

There are >22 million Americans with asthma. Chronic asthma is a worldwide problem with an increasing socioeconomic burden on individuals and on society. Recent advances have been made in diagnostic lung imaging, defining control of asthma, as well as in the education of patients with asthma. Accurate diagnosis of the cause of chronic cough in adults and of asthma in elderly individuals will help affected individuals receive appropriate treatment. Inhaled corticosteroids are the recommended first-line therapy for persistent asthma and can help prevent exacerbations in patients with asthma that are not well controlled. Early intervention and improved management can significantly reduce the socioeconomic burden of asthma. Patient education is an essential part of asthma management.

Inhaled and systemic corticosteroids in chronic obstructive pulmonary disease

Systemic and local inflammation is central to the pathophysiology of chronic obstructive pulmonary disease (COPD). Increased levels of inflammation have been linked to a more progressive course in COPD and have been shown to be present during an exacerbation. Decreases in inflammatory cytokines, C-reactive protein, and inflammatory cells have been observed with corticosteroid use, suggesting a possible mechanism for a therapeutic benefit of steroids. No available data support the routine use of systemic corticosteroids in stable COPD; however, short courses during exacerbations are likely to improve length of hospitalization, lung function, and relapse rate. Inhaled corticosteroids (ICS) decrease the rate of exacerbation and may improve the response to bronchodilators and decrease dyspnea in stable COPD. No study shows that ICS reduce the loss of lung function; however, recent data suggest a possible survival benefit when combined with long-acting beta agonists. There are limited data on the use of ICS in the treatment of acute exacerbations of COPD, and its role in this setting must be more clearly defined. The empiric use of systemic corticosteroids perioperatively represents another area of uncertainty. The role of pharmacogenetics in the metabolism of corticosteroids in COPD is evolving but may be partially responsible for the observed variability in patient responsiveness. The potential benefits of systemic or inhaled corticosteroid use must be weighed against the risk of known toxicities.

COPD as a systemic disease

Chronic obstructive pulmonary disease (COPD) represents an important and increasing burden throughout the world. Classically, COPD has been considered a respiratory condition only, mainly caused by tobacco smoking. However, COPD has important manifestations beyond the lungs, the so-called systemic effects. These include unintentional weight loss, skeletal muscle dysfunction, an increased risk of cardiovascular disease, osteoporosis, and depression, among others. Low-grade, chronic systemic inflammation is one of the key mechanisms underlying these systemic effects. Because these extra-pulmonary manifestations of COPD are common and/or may have significant implications for the patient wellbeing and prognosis, they warrant systematic screening and appropriate management in order to provide optimal medical care.

Soluble triggering receptor expressed on myeloid cells 1 is released in patients with stable chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is increasingly recognized as a systemic disease that is associated with increased serum levels of markers of systemic inflammation. The triggering receptor expressed on myeloid cells 1 (TREM-1) is a recently identified activating receptor on neutrophils, monocytes, and macrophage subsets. TREM-1 expression is upregulated by microbial products such as the toll-like receptor ligand lipoteichoic acid of Gram-positive or lipopolysaccharides of Gram-negative bacteria. In the present study, sera from 12 COPD patients (GOLD stages I-IV, FEV1 51 +/- 6%) and 10 healthy individuals were retrospectively analyzed for soluble TREM-1 (sTREM-1) using a newly developed ELISA. In healthy subjects, sTREM-1 levels were low (median 0.25 ng/mL, range 0-5.9 ng/mL). In contrast, levels of sTREM-1 in sera of COPD patients were significantly increased (median 11.68 ng/mL, range 6.2-41.9 ng/mL, P<.05). Furthermore, serum levels of sTREM-1 showed a significant negative correlation with lung function impairment. In summary, serum concentrations of sTREM-1 are increased in patients with COPD. Prospective studies are warranted to evaluate the relevance of sTREM-1 as a potential marker of the disease in patients with COPD.

COPD: magnesium in the plasma and polymorphonuclear cells of patients during a stable phase

Magnesium is one of the most important factors for regulation of inflammatory response as well as muscle function, and COPD is a multicomponent disease characterized by abnormal inflammatory response of the lungs with systemic muscle dysfunction. Because polymorphonuclear (PMN) cells are significantly represented in the pathogenesis of COPD, concentrations of total (tMg) and ionised magnesium (iMg) were determined in plasma and isolated PMN cells in 46 patients in stable phase of COPD (past smokers, current smokers, and non-smokers), 24 healthy smokers and 37 healthy non-smokers. In the same samples concentrations of total (tCa) and ionised calcium (iCa) were determined, due to the antagonism of magnesium towards calcium. We found decreased biological active iMg in PMN compared to the group of healthy non-smokers (5.42, 1.98-17.31 micromol/10(9) cells vs. 7.50, 3.27-15.15 micromol/10(9) cells, p < 0.05). In the plasma and isolated PMN of the patients the ratio of total calcium/total magnesium (tCa/tMg) was significantly increased (2.89, 2.15-3.86 and 1.19, 0.07-9.87) compared to the group of healthy non-smokers (2.65, 2.19-3.44 and 0.67, 0.14-2.40, p < 0.05) and to the group of healthy smokers (2.58, 2.26-3.24 and 0.66, 0.14-2.85, p < 0.05). In the group of patients the concentration of tCa was significantly increased in all samples compared to the healthy group of non-smokers and healthy smokers. The results of univariant logistic regression analysis for smoking, concentration of tCa and ratio of tCa/tMg in PMN showed high odds ratio for COPD status. These results raise a possibility that intracellular polymorphonuclear value of magnesium could be a distinctive marker for COPD risk disclosure among smokers.

Determination of Maximal Diaphragm Strength in Chronic Obstructive Pulmonary Disease: Cervical Magnetic Stimulation Versus Traditional Sniff Maneuver

OBJECTIVE

Magnetic stimulation of the diaphragm allows its strength to be assessed. The clinical applications of this technique are becoming more widespread given that the patient's cooperation is not required. The aim of the present study was to compare this inhalation technique with traditional voluntary forced inspiration (sniff test) in a group of patients with chronic obstructive pulmonary disease (COPD).

PATIENTS AND METHODS

Sixteen men with moderate-to-severe COPD were studied (mean [SD] forced expiratory volume in 1 second, 35% [15%] of the reference value). For all patients, the maximal transdiaphragmatic pressure (a measure of the contractility of the muscle) was determined at peak inspiration and during cervical magnetic stimulation.

RESULTS

A moderate correlation between measurements with the 2 techniques was observed. The value obtained with stimulation was approximately 20% of that obtained with the sniff maneuver (22 [7] cm H2O vs 97 [27] cm H2O, respectively). The stimulation technique yielded an intraindividual coefficient of variability of 12% (7%) and an interindividual one of 33% (6%). Very similar values for these coefficients were obtained with the sniff maneuver. Qualitative analysis of the stimulation technique showed it to have a high sensitivity (89%) for diagnosing muscle weakness, with few false negatives. In contrast, specificity was very low (43%), and false positives for muscle weakness were relatively common. The overall effectiveness of the prediction was acceptable (69%).

CONCLUSIONS

Cervical magnetic stimulation appears to be a good clinical option for ruling out diaphragm weakness. It is particularly indicated in patients with limited capacity for understanding instructions or those unable to cooperate.

Chronic Obstructive Pulmonary Disease, inflammation and co-morbidity--a common inflammatory phenotype?

Chronic Obstructive Pulmonary Disease (COPD) is and will remain a major cause of morbidity and mortality worldwide. The severity of airflow obstruction is known to relate to overall health status and mortality. However, even allowing for common aetiological factors, a link has been identified between COPD and other systemic diseases such as cardiovascular disease, diabetes and osteoporosis.

COPD is known to be an inflammatory condition and neutrophil elastase has long been considered a significant mediator of the disease. Pro-inflammatory cytokines, in particular TNF-α (Tumour Necrosis Factor alpha), may be the driving force behind the disease process. However, the roles of inflammation and these pro-inflammatory cytokines may extend beyond the lungs and play a part in the systemic effects of the disease and associated co-morbidities. This article describes the mechanisms involved and proposes a common inflammatory TNF-α phenotype that may, in part, account for the associations.

Systemic Immunological Response to Exercise in Patients with Chronic Obstructive Pulmonary Disease: What Does It Mean?

Chronic obstructive pulmonary disease (COPD) is no longer seen as a pulmonary disease, but is increasingly associated with systemic effects with important clinical relevance. Systemic immunological changes in COPD patients are characterized by an increased number of circulating inflammatory cells, functional changes of the inflammatory cells, elevated plasma levels of cytokines, and oxidative stress. Physical exercise induces an abnormal systemic inflammatory and oxidative response in COPD patients, which is seen in both the circulation and the peripheral muscles. Although mechanisms and consequences of these effects are not yet fully understood, they could be harmful in COPD patients by inducing damage or functional changes in, for example, skeletal muscles. Whether these changes of the immune system can also affect the susceptibility to infections in these patients is unknown. The concept of COPD as a systemic rather than only a pulmonary disease also opens new perspectives on the development for new therapeutic interventions. The effects of new antioxidative and anti-inflammatory agents are investigated. A better understanding of the complexity of the systemic effects will aid the development of new therapies and management strategies for patients with COPD.

Systemic inflammatory response to exhaustive exercise in patients with chronic obstructive pulmonary disease

Systemic inflammation may be present in patients with chronic obstructive pulmonary disease (COPD). Exercise is known to elicit an inflammatory response. We hypothesized that the systemic inflammatory response to exercise might be exaggerated in COPD patients compared to healthy subjects. Sixteen COPD patients and 11 healthy subjects performed a maximal incremental bicycle test. Before and at maximal exercise arterial blood samples were taken to determine circulating catecholamines, (subsets of) leukocytes, acute phase proteins, creatine kinase and myoglobin. At rest, increased levels of norepinephrine and systemic inflammation were present in COPD. The response of catecholamines to exercise was lower in COPD patients (P<0.01), which in part was due to the lower maximal exercise capacity of these patients (P<0.01). Exercise-induced leukocytosis showed similar responses in both groups, but occurred at higher levels in COPD. Although patients had increased levels of CRP at rest (P<0.001), exercise did not affect acute phase proteins. No systemic signs of muscle damage were found. The present study shows that COPD patients are exposed to systemic inflammation that is intensified by exhaustive exercise. The inflammatory response in COPD is not exaggerated compared to healthy subjects but occurs at a higher level and is observed at lower external workload.

Impact of CFTR ΔF508 mutation on prostaglandin E2production and type IIA phospholipase A2expression by pulmonary epithelial cells

Cystic fibrosis (CF) is characterized by an exacerbated inflammatory pulmonary response with excessive production of inflammatory mediators. We investigated here the impact of cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction on prostaglandin E2(PGE2) production and type IIA secreted phospholipase A2(sPLA2-IIA) expression. We show that both resting and LPS-stimulated human respiratory epithelial cell line bearing ΔF508 mutation on CFTR (CF cells) released more PGE2than control cell line. This was accompanied by enhanced expression and activity of cyclooxygenase-2 in CF cells. PGE2release was attenuated after experimentally induced retrafficking of the ΔF508-CFTR at the plasma membrane. sPLA2-IIA expression occurred at higher levels in CF cells than in control cells and was enhanced by LPS and PGE2. Suppression of PGE2synthesis by aspirin led to an inhibition of LPS-induced sPLA2-IIA expression. Higher activation of NF-κB was observed in CF cells compared with control cells and was enhanced by LPS. However, addition of PGE2or aspirin had no effect on NF-κB activation. LPS-induced sPLA2-IIA expression was reduced by an NF-κB inhibitor. We suggest that the lack of the CFTR in the plasma membrane results in a PGE2overproduction and an enhanced sPLA2-IIA expression. This expression is upregulated by NF-κB and amplified by PGE2via a unidentified signaling pathway.

Clinical pharmacology of etoricoxib

Etoricoxib is a highly selective COX-2 inhibitor (coxib) approved in Europe for the treatment of osteoarthritis (OA), rheumatoid arthritis and acute gouty arthritis. Etoricoxib is an effective analgesic drug that has shown some improved efficacy versus traditional NSAIDs and it is the only coxib approved for the treatment of acute gouty arthritis. Moreover, recent studies evidence its efficacy in patients with ankylosing spondylitis. In the Etoricoxib Diclofenac Gastrointestinal Evaluation study performed in patients with OA, etoricoxib significantly reduced the rate of discontinuation by 50% due to gastrointestinal adverse events versus diclofenac. Comparable rates of thrombotic cardiovascular events were detected. Rates of discontinuation due to hypertension-related adverse effects were higher on etoricoxib than diclofenac. Similarly to other selective COX-2 inhibitors, etoricoxib is contraindicated in patients with ischaemic heart disease or stroke and it should be used with caution in patients with risk factors for heart disease. The European Medicines Agency has contraindicated the use of etoricoxib in patients with uncontrolled hypertension. Selective COX-2 inhibitors remain an appropriate choice in patients at low cardiovascular risk, but with increased risk of gastrointestinal complications.

The Role of Oxidative Stress in the Pathogenesis??of COPD

Chronic inflammation and oxidative stress are important features in the pathogenesis of COPD. The increased oxidative stress in patients with COPD is the result of an increased burden of inhaled oxidants, as well as increased amounts of reactive oxygen species (ROS) generated by various inflammatory, immune and epithelial cells of the airways. Oxidative stress has important implications on several events of lung physiology and for the pathogenesis of COPD. These include oxidative inactivation of antiproteases and surfactants, mucus hypersecretion, membrane lipid peroxidation, mitochondrial respiration, alveolar epithelial injury, remodeling of extracellular matrix, and apoptosis. An increased level of ROS produced in the airways is reflected by increased markers of oxidative stress in the airspaces, sputum, breath, lungs, and blood in patients with COPD. The biomarkers of oxidative stress such as H2O2, F2-isoprostanes, malondialdehyde and 4-hydroxy-2-nonenal have been successfully measured in breath condensate. ROS and aldehydes play a key role in enhancing the inflammation through the activation of mitogen-activated protein kinases and redox-sensitive transcription factors such as nuclear factor kappa B and activator protein-1. Oxidative stress also alters nuclear histone acetylation and deacetylation leading to increased gene expression of pro-inflammatory mediators in the lung. Oxidative stress may play a role in the poor clinical efficacy of corticosteroids in the treatment of COPD. Since a variety of oxidants, free radicals, and aldehydes are implicated in the pathogenesis of COPD it is likely that a combination of antioxidants may be effective in the treatment of COPD. Antioxidant compounds may also be of therapeutic value in monitoring oxidative biomarkers indicating disease progression. Various approaches to enhance the lung antioxidant screen and the clinical effectiveness of antioxidant compounds in the treatment of COPD are discussed.

Effect of 5-lipoxygenase on the development of pulmonary hypertension in rats

5-Lipoxygenase (5-LO) and its downstream leukotriene products have been implicated in the development of pulmonary hypertension. In this study, we examined the effects of 5-LO overexpression in rat lungs on pulmonary hypertension using a recombinant adenovirus expressing 5-LO (Ad5-LO). Transthoracic echocardiography and right heart catheterization data showed that 5-LO overexpression in the lung did not cause pulmonary hypertension in normal rats; however, it markedly accelerated the progression of pulmonary hypertension in rats treated with monocrotaline (MCT). An increase in pulmonary artery pressure occurred earlier in the rats treated with MCT + Ad5-LO (7-10 days) compared with those treated with control vector, MCT + adenovirus expressing green fluorescent protein (AdGFP), or MCT alone (15-18 days). The weight ratio of the right ventricle to left ventricle plus septum was higher in the MCT + Ad5-LO group than that of the MCT + AdGFP or MCT group (0.45 +/- 0.08 vs. 0.35 +/- 0.03 or 0.33 +/- 0.06). Lung tissue histological sections from MCT + Ad5-LO rats exhibited more severe inflammatory cell infiltration and pulmonary vascular muscularization than those from MCT + AdGFP- or MCT-treated rats. Administration of 5-LO inhibitors, zileuton or MK-886, to either MCT- or MCT + Ad5-LO-treated rats prevented the development of pulmonary hypertension. These data suggest that 5-LO plays a critical role in the progression of pulmonary hypertension in rats and that the detrimental effect of 5-LO is manifest only in the setting of pulmonary vascular endothelial cell dysfunction.

Skeletal muscle changes in patients with obstructive sleep apnoea syndrome

Previous studies have shown that chronic hypoxia leads to changes in skeletal muscle structure (fibre size and type) and activities of several bioenergetic enzymes. Whether this occurs also in conditions characterised by intermittent hypoxia, such as the obstructive sleep apnoea syndrome (OSAS), is unknown. To explore this possibility, we obtained a needle biopsy of the quadriceps femoris in 12 consecutive stable outpatients with severe OSAS (52 +/- 9 year, apnoea-hypopnoea index 70 +/- 14 h(-1)) (x +/- SD) and in six healthy volunteers (49 +/- 8 year), where we quantified fibre type, size and protein content, as well as phosphofructo-kinase (PFK) and cytochrome oxidase (CytOx) activities. We found that fibre-type distribution was similar in patients and controls. In contrast, the diameter of type II fibres (74 +/- 10 microm vs. 56 +/- 11 microm, P < 0.05) and protein content (100 +/- 14 vs. 88 +/- 8 microg/mg) was higher in patients with OSAS. Likewise, we observed upregulation of CytOx (0.93 +/- 0.38 vs. 0.40 +/- 0.22 microkat/mg protein, P < 0.01) and PFK activities (5.35 +/- 4.8 vs. 1.3 +/- 1.3 microkat/ mg protein, P < 0.05) in patients with OSAS. These results show that, paralleling which occurs in conditions characterised by continuous hypoxia, patients with OSAS (and intermittent hypoxia) also show structural and bioenergetic changes in their skeletal muscle.

Weight loss in chronic obstructive pulmonary disease. Mechanisms and implications

Weight loss occurs frequently in patients with chronic obstructive pulmonary disease (COPD). Although the precise cellular mechanisms underlying weight loss in COPD are unclear, this is a clinically relevant phenomenon because it contributes to limit the exercise capacity of these patients and, therefore, it jeopardizes their quality of life. More importantly, it is a negative prognostic factor that is independent of the degree of lung function impairment present. Thus, weight loss in COPD constitutes a new therapeutic target. This article reviews the mechanisms and potential consequences of weight loss in COPD and highlights areas that needed future research. It is hoped that a better understanding of its pathogenesis may eventually contribute to the development of new therapeutic strategies that contribute to improve the well-being and/or long-term prognosis of patients suffering from this devastating disease and, potentially, from others characterized also by unexplained weight loss.

Chronic obstructive pulmonary disease. 5: systemic effects of COPD

The role of body cell mass wasting, muscle wasting, and changes in muscle metabolism in the pathogenesis of chronic obstructive pulmonary disease is reviewed.

Effect of theophylline on induced sputum inflammatory indices and neutrophil chemotaxis in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterized by a neutrophilic airway inflammation that can be demonstrated by examination of induced sputum. Theophylline has antiinflammatory effects in asthma, and in the present study we investigated whether a similar effect occurs in COPD patients treated with low doses of theophylline. Twenty-five patients with COPD were treated with theophylline (plasma level of 9-11 mg/L) for 4 weeks in a placebo-controlled, randomized, double-blind crossover study. Theophylline was well tolerated. Induced sputum inflammatory cells, neutrophils, interleukin-8, myeloperoxidase, and lactoferrin were all significantly reduced by about 22% by theophylline. Neutrophils from subjects treated with theophylline showed reduced chemotaxis to N-formyl-met-leu-phe (approximately 28%) and interleukin-8 (approximately 60%). Neutrophils from a healthy donor showed reduced chemotaxis (approximately 30%) to induced sputum samples obtained during theophylline treatment. These results suggest that theophylline has antiinflammatory properties that may be useful in the long-term treatment of COPD.

Calcium-dependent synthesis of prostacyclin in ATP-stimulated venous endothelial cells

Prostacyclin is a powerful vasodilator that is released from vascular endothelial cells. Previous studies in our laboratory have indicated that arachidonic acid metabolites from venous endothelium play an important role in the dilation of adjacent arterioles during muscle stimulation. Furthermore, recent studies have suggested that ATP released from red blood cells during hypoxia stimulates dilation of arterioles. We tested the hypothesis that an ATP-induced increase in intracellular Ca(2+) in venous endothelium promotes prostacyclin synthesis. Small branches of femoral veins were isolated from male golden hamsters, placed in a 1 mL bath, and cannulated for perfusion with 3-(N-morpholino) propanesulfonic acid (MOPS)-buffered physiological salt solution at 37 degrees C. Prostacyclin synthesis was determined by enzyme immunoassay of bath solution. Perfusion of veins with ATP increased prostacyclin synthesis from 50 +/- 5 to 627 +/- 46 pg/mL (n=49). ATP-induced prostacyclin synthesis was inhibited by removal of extracellular Ca(2+), chelation of intracellular Ca(2+) with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) (10 micromol/L for 10 minutes), and preincubation with cytosolic phospholipase A(2) (PLA(2)) inhibitors, AACOCF(3), and bromoenol lactone. Changes in intracellular Ca(2+) in cultured human venous endothelial cells were assessed by fura-2 spectrofluorometry. ATP induced a transient Ca(2+) peak within seconds, and the subsequent Ca(2+) plateau was abolished by removal of extracellular Ca(2+). An increase in prostacyclin synthesis was detected in these cells 2 minutes after application of ATP. These findings suggest that the ATP-induced increase in intracellular Ca(2+) stimulates prostacyclin synthesis in venous endothelial cells.