New approaches to the management of COPD

Novel protein biomarkers for pneumonia and acute exacerbations in COPD: a pilot study

Introduction

Community-acquired pneumonia (CAP) and acute exacerbations of chronic obstructive pulmonary disease (AECOPD) result in high morbidity, mortality, and socio-economic burden. The usage of easily accessible biomarkers informing on disease entity, severity, prognosis, and pathophysiological endotypes is limited in clinical practice. Here, we have analyzed selected plasma markers for their value in differential diagnosis and severity grading in a clinical cohort.

Methods

A pilot cohort of hospitalized patients suffering from CAP (n = 27), AECOPD (n = 10), and healthy subjects (n = 22) were characterized clinically. Clinical scores (PSI, CURB, CRB65, GOLD I-IV, and GOLD ABCD) were obtained, and interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-2-receptor (IL-2R), lipopolysaccharide-binding protein (LBP), resistin, thrombospondin-1 (TSP-1), lactotransferrin (LTF), neutrophil gelatinase-associated lipocalin (NGAL), neutrophil-elastase-2 (ELA2), hepatocyte growth factor (HGF), soluble Fas (sFas), as well as TNF-related apoptosis-inducing ligand (TRAIL) were measured in plasma.

Results

In CAP patients and healthy volunteers, we found significantly different levels of ELA2, HGF, IL-2R, IL-6, IL-8, LBP, resistin, LTF, and TRAIL. The panel of LBP, sFas, and TRAIL could discriminate between uncomplicated and severe CAP. AECOPD patients showed significantly different levels of LTF and TRAIL compared to healthy subjects. Ensemble feature selection revealed that CAP and AECOPD can be discriminated by IL-6, resistin, together with IL-2R. These factors even allow the differentiation between COPD patients suffering from an exacerbation or pneumonia.

Discussion

Taken together, we identified immune mediators in patient plasma that provide information on differential diagnosis and disease severity and can therefore serve as biomarkers. Further studies are required for validation in bigger cohorts.

Genetic polymorphisms of matrix metalloproteinases and protein levels in chronic obstructive pulmonary disease in a Mexican population

AIM

To evaluate association of single nucleotide polymorphisms (SNPs) in the MMP1, MMP2, MMP9 and MMP12 genes and serum MMP-2 and MMP-9 levels in smoking chronic obstructive pulmonary disease (COPD) patients.

MATERIALS & METHODS

Genotyping using real-time PCR in 330 smokers with COPD (COPD), 658 smokers without COPD (SNC) and 150 nonsmokers (NCNS), the analysis of samples used was χ(2) test. Using ELISA, the proteins were evaluated. Multiple comparisons were made by ANOVA.

RESULTS

rs243864 (OR: 7.44; 95% CI: 3.62-15.26) and rs11646643 (OR: 1.58; 95% CI: 1.07-2.34) of the MMP-2 gene and rs3918253 (OR: 1.72; 95% CI: 1.08-2.71) of the MMP-9 gene, were associated with the risk of COPD. Serum MMP-2 level in the COPD group was lower compared with SNC (p < 0.05). Serum MMP-9 level was elevated in the COPD group compared with SNC (p < 0.05).

CONCLUSION

Polymorphisms in MMP2 and MMP9 but not in MMP1 and MMP12 are associated with the risk of COPD in the Mexican mestizo population.

Airway malacia in chronic obstructive pulmonary disease: prevalence, morphology and relationship with emphysema, bronchiectasis and bronchial wall thickening

The aim of this study was to determine the prevalence of airway malacia and its relationship with ancillary morphologic features in patients with chronic obstructive pulmonary disease (COPD). A retrospective review was performed of a consecutive series of patients with COPD who were imaged with inspiratory and dynamic expiratory multidetector computed tomography (MDCT). Airway malacia was defined as > or =50% expiratory reduction of the airway lumen. Both distribution and morphology of airway malacia were assessed. The extent of emphysema, extent of bronchiectasis and severity of bronchial wall thickness were quantified. The final study cohort was comprised of 71 patients. Airway malacia was seen in 38 of 71 patients (53%), and such proportion was roughly maintained in each stage of COPD severity. Almost all tracheomalacia cases (23/25, 92%) were characterised by an expiratory anterior bowing of the posterior membranous wall. Both emphysema and bronchiectasis extent did not differ between patients with and without airway malacia (p > 0.05). Bronchial wall thickness severity was significantly higher in patients with airway malacia and correlated with the degree of maximal bronchial collapse (p < 0.05). In conclusion, we demonstrated a strong association between airway malacia and COPD, disclosing a significant relationship with bronchial wall thickening.

The selective MMP-12 inhibitor, AS111793 reduces airway inflammation in mice exposed to cigarette smoke

BACKGROUND

Macrophage elastase (MMP-12) is involved in the inflammatory process of chronic obstructive pulmonary disease (COPD). The aim of this study was to investigate in mice the effect of MMP-12 inhibition on the inflammatory process induced by cigarette smoke (CS) or by lipopolysaccharide (LPS) exposure of the airways.

EXPERIMENTAL APPROACH

C57BL/6 mice were given, orally, either the selective MMP-12 inhibitor AS111793 (3, 10, 30 and 100 mg kg(-1)), the PDE-4 inhibitor roflumilast (3 mg kg(-1)) or vehicle, then exposed to CS (for 3 days) or to LPS (100 microg mL(-1), 30 min). Subsequent to the last smoke or LPS exposure, bronchoalveolar lavages (BAL) were performed and lungs were removed and homogenized to analyze various markers of inflammation at appropriate times.

KEY RESULTS

Inhibition of MMP-12 by AS111793 (10 and 30 mg kg(-1)) was associated with a reduction of the increase in neutrophil number in BAL fluids after 4 days and of macrophages after 11 days. On day 4, AS111793 also significantly reduced all the inflammation markers that had increased after CS exposure, including soluble TNF receptors I and II, MIP-1gamma, IL-6 and pro-MMP-9 activity in BAL fluids, and KC/CXCL1, fractalkine/CX3CL1, TIMP-1 and I-TAC/CXCL11 in lung parenchyma. In contrast, inhibition of MMP-12 did not reduce neutrophil influx, pro-MMP-9 activity or KC/CXCL1 release in BAL fluids of mice exposed to LPS.

CONCLUSION

Inhibition of MMP-12 with AS111793, reduced the inflammatory process associated with exposure of mice to CS, strongly suggesting a specific involvement of MMP-12 in lung inflammation following CS exposure.

A segment of gamma ENaC mediates elastase activation of Na+ transport

The epithelial Na⁺ channel (ENaC) that mediates regulated Na⁺ reabsorption by epithelial cells in the kidney and lungs can be activated by endogenous proteases such as channel activating protease 1 and exogenous proteases such as trypsin and neutrophil elastase (NE). The mechanism by which exogenous proteases activate the channel is unknown. To test the hypothesis that residues on ENaC mediate protease-dependent channel activation wild-type and mutant ENaC were stably expressed in the FRT epithelial cell line using a tripromoter human ENaC construct, and protease-induced short-circuit current activation was measured in aprotinin-treated cells. The amiloride-sensitive short circuit current (I_Na) was stimulated by aldosterone (1.5-fold) and dexamethasone (8-fold). Dexamethasone-treated cells were used for all subsequent studies. The serum protease inhibitor aprotinin decreased baseline I_Na by approximately 50% and I_Na could be restored to baseline control values by the exogenous addition of trypsin, NE, and porcine pancreatic elastase (PE) but not by thrombin. All protease experiments were thus performed after exposure to aprotinin. Because NE recognition of substrates occurs with a preference for binding valines at the active site, several valines in the extracellular loops of α and γ ENaC were sequentially substituted with glycines. This scan yielded two valine residues in γ ENaC at positions 182 and 193 that resulted in inhibited responses to NE when simultaneously changed to other amino acids. The mutations resulted in decreased rates of activation and decreased activated steady-state current levels. There was an ∼20-fold difference in activation efficiency of NE against wild-type ENaC compared to a mutant with glycine substitutions at positions 182 and 193. However, the mutants remain susceptible to activation by trypsin and the related elastase, PE. Alanine is the preferred P₁ position residue for PE and substitution of alanine 190 in the γ subunit eliminated I_Na activation by PE. Further, substitution with a novel thrombin consensus sequence (LVPRG) beginning at residue 186 in the γ subunit (γ_Th) allowed for I_Na activation by thrombin, whereas wild-type ENaC was unresponsive. MALDI-TOF mass spectrometric evaluation of proteolytic digests of a 23-mer peptide encompassing the identified residues (T¹⁷⁶-S¹⁹⁸) showed that hydrolysis occurred between residues V193 and M194 for NE and between A190 and S191 for PE. In vitro translation studies demonstrated thrombin cleaved the γ_Th but not the wild-type γ subunit. These results demonstrate that γ subunit valines 182 and 193 are critical for channel activation by NE, alanine 190 is critical for channel activation by PE, and that channel activation can be achieved by inserting a novel thrombin consensus sequence. These results support the conclusion that protease binding and perhaps cleavage of the γ subunit results in ENaC activation.

Mucolytic activity of bacterial and human chitinases

Several pulmonary pathologies, like cystic fibrosis (CF), are characterized by hypersecretion and stasis of tenacious mucus. Bacterial glycosidases are known to degrade mucins but their use as mucolytic agents is questionable. The observation that bacterial chitinases degrade mucins and the recent discovery of human chitinases, which have been proposed to be involved in the genesis of asthma, prompted us to evaluate the mucolytic properties of human derived chitinases. The effect of these human chitinases, and bacterial chitinases (positive control), on the viscoelasticity of CF sputa and on the electrophoretic mobility of human mucins was tested. Commercial bacterial chitinase drastically degraded CF sputum, while human derived chitinases did not. Accordingly, the commercial bacterial chitinase was found to degrade mucins, whereas recombinant human chitinases did not. A thorough analysis of the commercial chitinase elucidated that contaminating proteases and also nucleases assisted in the mucolytic effect. Indeed, recombinant bacterial chitinases very slightly reduced the viscoelasticity of CF sputum, but they caused a significant degradation of the CF sputum when they were combined with proteases. In conclusion, this work shows that recombinant human and recombinant bacterial chitinases have no or very low mucolytic activities, respectively. The observed mucolytic properties of commercial bacterial chitinase are due to a synergistic effect between chitinolytic and proteolytic enzymes at one hand and at the other hand also due to the presence of contaminating nucleases.

Polymorphisms in the promoter region of neutrophil elastase gene and lung cancer risk

The neutrophil elastase (NE) gene encodes a powerful serine protease that is involved in the process of normal tissue turnover, natural host defense or tissue damage in acute and chronic inflammatory disorders. Furthermore, NE was suggested as one of the determinant factors of individual susceptibility to lung cancer resulting from imbalance between alpha1-antitrypsin (AT) and NE. To determine whether NE plays a role in risk for lung cancer, we screened polymorphisms in the promoter region of the NE gene and assessed the role of the NE polymorphisms in the risk for lung cancer. We confirmed three previously identified polymorphisms which are located at -903, -741, and extra 52 bp STS relative to the transcription initiation site. In addition, two new polymorphisms at -832 (G/T) and -789 (C/T) were identified. Their rare allelic frequencies of new polymorphism are 0.02 and 0.01, respectively, among Caucasians. The prevalence of the NE -903 (T/T) and (T/G) genotypes were 0.88 and 0.12 in controls as compared to 0.96 and 0.04 in lung cancer patients using genomic DNA isolated from 113 Caucasian lung cancer cases and 131 controls. A significant increase in lung cancer risk was observed for expected high NE activity genotypes (OR=3.2, 95% CI=1.02-10.3) as compared to low NE activity genotypes. These results were consistent with previous in vitro functional analysis, which reported an approximately two-fold increase enzyme expression with the -903T/-741G allele as compared to the -903G/-741A variant. These results confirm that the NE promoter region polymorphisms may influence in risk for lung cancer.

Respiratory lumenal change of the pharynx and trachea in normal subjects and COPD patients: assessment by cine-MRI

The purpose of this study was to use cine-MRI during continuous respiration to measure the respiratory lumenal diameter change in the pharynx and at an upper tracheal level. Fifteen non-smokers and 23 chronic obstructive pulmonary disease (COPD) patients with smoking history (median 50 pack-years) were included. Cine-MRI with seven frames/s was performed during continuous respiration. Minimal and maximal cross-sectional lumenal diameters within the pharynx and the upper tracheal lumen area were measured. The median diameter change in the pharynx (tracheal area) was 70% (1.4 cm(2)) in volunteers and 76% (1.7 cm(2)) in smokers (P=0.98, P=0.04). Tracheal lumenal collapse was a median of 43% in volunteers and 64% in smokers (P=0.011). No clear disease-related difference of the pharynx-lumen was found. The maximal cross-sectional area of the upper trachea lumen as well as the respiratory collapse was larger in COPD patients than in normal subjects. This information is important for the modelling of ventilation and prediction of drug deposition, which are influenced by the airway diameter.

Divergent effects of alpha1-antitrypsin on neutrophil activation, in vitro

alpha1-Antitrypsin (AAT) is a major circulating serine proteinase inhibitor in humans. The anti-proteinase activity of AAT is inhibited by chemical modification. These include inter- or intramolecular polymerisation, oxidation, complex formation with target proteinases (e.g., neutrophil elastase), and/or cleavage by multi-specific proteinases. In vivo, several modified forms of AAT have been identified which stimulate biological activity in vitro unrelated to inhibition of serine proteinases. In this study we have examined the effects of native and polymerised AAT and C-36 peptide, a proteolytic cleavage product of AAT, on human neutrophil activation, in vitro. We show that the C-36 peptide displays striking concentration-dependent pro-inflammatory effects on human neutrophils, including induction of neutrophil chemotaxis, adhesion, degranulation, and superoxide generation. In contrast to C-36 peptide, native and polymerised AAT at similar and higher concentrations showed no effects on neutrophil activation. These results suggest that cleavage of AAT may not only abolish its proteinase inhibitor activity, but can also generate a powerful pro-inflammatory activator for human neutrophils.

Long-acting inhaled beta 2-agonists for stable COPD

OBJECTIVE

To describe the pathogenesis of chronic obstructive pulmonary disease (COPD) and mechanisms of benefit, formulations available, drug costs, pharmacokinetic profiles, and pertinent clinical studies for long-acting beta(2)-agonists.

DATA SOURCES

A MEDLINE search was conducted from July 1966 through October 2002.

STUDY SELECTION AND DATA EXTRACTION

Pertinent articles related to COPD and long-acting beta(2)-agonists.

DATA SYNTHESIS

The incidence and subsequent morbidity and mortality of COPD have increased during the last 4 decades, prompting worldwide initiatives to formulate guidelines to decrease the burden of this disease. COPD is a progressive, irreversible disease state characterized by chronic cough, dyspnea, sputum production, and wheezing, in which no medication has been shown to decrease mortality, excluding oxygen supplementation. Bronchodilators have been a mainstay of COPD treatment through their ability to work by both smooth- and non-smooth-muscle mechanisms. Long-acting beta(2)-agonists (i.e., formoterol, salmeterol) dosed twice daily provide more convenient dosing than 4-times-daily regimens of traditional short-acting bronchodilators. Both formoterol and salmeterol have acceptable adverse event profiles when used at recommended doses. There have been no direct clinical outcome studies comparing formoterol and salmeterol, but both have shown some benefits over ipratropium and theophylline in improving the symptoms, spirometric indices, exacerbations, and quality of life of patients with COPD.

CONCLUSIONS

Based on current evidence, long-acting beta(2)-agonists are acceptable first-line agents for patients with COPD.

Storytelling and the interpretation of meaning in qualitative research

AIM

This paper reviews literature on narrative analysis and illustrates the meaning-making function of stories of chronic illness through analysis and discussion of two case studies from a study of acute episodes of chronic obstructive pulmonary disease (COPD).

BACKGROUND

Individuals living with COPD experience acute exacerbations characterized by extreme dyspnea, but there has been little research to provide understanding of these events from the perspectives of individuals with COPD, family caregivers, and nurses. Narrative analysis -- considered in the context of the aims of qualitative research -- illuminates how these people make sense of acute exacerbation events by telling stories.

DESIGN AND METHODS

In an ethnographic study, 10 patient-family nurse units in two Canadian general hospitals participated in interviews concerning acute episodes of COPD. Narrative analysis enabled identification of several story forms and their functions.

RESULTS

Examples were found of a story told twice with different meanings, and of a patient's 'death story' used to communicate distrust of the nurse's ability to recognize the seriousness of distress and implications for its potential course. These examples are presented, and interpreted with respect to issues of meaning.

CONCLUSIONS

The analysis indicates that stories told by patients in the context of nurse-client interactions inform understanding of the individual's acute exacerbation events beyond the biophysical.

Recent advances in diagnosis and management of chronic bronchitis and emphysema

Chronic obstructive pulmonary disease is a progressive inflammatory disease of the airways and lung parenchyma. Expiratory airflow limitation is the hallmark of chronic obstructive pulmonary disease. It is a significant cause of morbidity and mortality in the United States and worldwide and results in a large consumption of health care resources. Unfortunately, despite efforts to curb this disease, its prevalence is increasing. The diagnosis is usually made when the patient complains of dyspnea on exertion; by this time, irreversible structural damage to the lung has already occurred. Given the nonspecific symptoms of the disease and the inability to effectively treat and reverse the damage, it is essential to diagnose the disease in its early stages and take the necessary preventive measures, thus avoiding disability or death. This review summarizes the latest developments in the diagnosis and management of chronic obstructive pulmonary disease. The first half of the review discusses functional, radiographic, biochemical, and cellular/histopathologic issues in the diagnosis of chronic obstructive pulmonary disease. The second half focuses on the current pharmacologic and nonpharmacologic advances in chronic obstructive pulmonary disease, including the role of respiratory support and surgical treatment. Based on the research on the cellular mechanisms of chronic obstructive pulmonary disease, the review also makes a reference to novel and experimental therapies for chronic obstructive pulmonary disease.

Proteinase activity regulation by glycosaminoglycans

There are few reports concerning the biological role and the mechanisms of interaction between proteinases and carbohydrates other than those involved in clotting. It has been shown that the interplay of enzymes and glycosaminoglycans is able to modulate the activity of different proteases and also to affect their structures. From the large number of proteases belonging to the well-known protease families and also the variety of carbohydrates described as widely distributed, only few events have been analyzed more deeply. The term "family" is used to describe a group of proteases in which every member shows an evolutionary relationship to at least one other protease. This relationship may be evident throughout the entire sequence, or at least in that part of the sequence responsible for catalytic activity. The majority of proteases belong to the serine, cysteine, aspartic or metalloprotease families. By considering the existing limited proteolysis process, in addition to the initial idea that the proteinases participate only in digestive processes, it is possible to conclude that the function of the enzymes is strictly limited to the cleavage of intended substrates since the destruction of functional proteins would result in normal tissue damage. In addition, the location as well as the eventual regulation of protease activity promoted by glycosaminoglycans can play an essential role in the development of several physiopathological conditions.

Mutations in the ELA2 gene encoding neutrophil elastase are present in most patients with sporadic severe congenital neutropenia but only in some patients with the familial form of the disease

Severe congenital neutropenia (SCN) was originally described as an autosomal recessive disorder. Subsequently, autosomal dominant and sporadic forms of the disease have been recognized. All forms are manifest by persistent severe neutropenia and recurrent bacterial infection. In contrast, cyclical hematopoiesis is characterized by periodic neutropenia inter-spaced with (near) normal neutrophil counts. Recently, linkage analysis on 13 affected pedigrees identified chromosome 19p13.3 as the likely position for mutations in cyclical hematopoiesis. Heterozygous mutations in the ELA2 gene encoding neutrophil elastase were detected in all families studied. Further work also demonstrated mutations in ELA2 in sporadic and autosomal dominant SCN. However, all mutations described to date are heterozygous and thus appear to act in a dominant fashion, which is inconsistent with an autosomal recessive disease. Therefore, the current study investigated whether mutations in ELA2 could account for the disease phenotype in classical autosomal recessive SCN and in the sporadic and autosomal dominant types. All 5 exons of ELA2 and their flanking introns were studied in 18 patients (3 autosomal recessive, 5 autosomal dominant [from 3 kindreds], and 10 sporadic) using direct automated sequencing. No mutations were found in the autosomal recessive families. A point mutation was identified in 1 of 3 autosomal dominant families, and a base substitution was identified in 8 of 10 patients with the sporadic form, though 1 was subsequently shown to be a low-frequency polymorphism. These results suggest that mutations in ELA2 are not responsible for classical autosomal recessive Kostmann syndrome but provide further evidence for the role of ELA2 in SCN.

Acute mountain sickness; prophylactic benefits of antioxidant vitamin supplementation at high altitude

Acute mountain sickness; prophylactic benefits of Free-radical-mediated damage to the blood-brain barrier may be implicated in the pathophysiology of acute mountain sickness (AMS). To indirectly examine this, we conducted a randomized double-blind placebo-controlled trial to assess the potentially prophylactic benefits of enteral antioxidant vitamin supplementation during ascent to high altitude. Eighteen subjects aged 35 +/- 10 years old were randomly assigned double-blind to either an antioxidant (n = 9) or placebo group (n = 9). The antioxidant group ingested 4 capsules/day(-1) (2 after breakfast/2 after evening meal) that each contained 250 mg of L-ascorbic acid, 100 IU of dl-a-tocopherol acetate and 150 mg of alpha-lipoic acid. The placebo group ingested 4 capsules of identical external appearance, taste, and smell. Supplementation was enforced for 3 weeks at sea level and during a 10-day ascent to Mt. Everest base camp (approximately 5,180 m). Antioxidant supplementation resulted in a comparatively lower Lake Louise AMS score at high altitude relative to the placebo group (2.8 +/- 0.8 points versus 4.0 +/- 0.4 points, P = 0.036), higher resting arterial oxygen saturation (89 +/- 5% versus 85 +/- 5%, P = 0.042), and total caloric intake (13.2 +/- 0.6 MJ/day(-1) versus 10.1 +/- 0.7 MJ/day(-1), P = 0.001); the latter is attributable to a lower satiety rating following a standardized meal. These findings indicate that the exogenous provision of water and lipid-soluble antioxidant vitamins at the prescribed doses is an apparently safe and potentially effective intervention that can attenuate AMS and improve the physiological profile of mountaineers at high altitude.