Chronic obstructive pulmonary disease

Markers of disease severity in chronic obstructive pulmonary disease

BACKGROUND AND OBJECTIVES

Diagnosis and assessment of treatment effect in chronic obstructive pulmonary disease (COPD) have relied primarily on the examination of a complex set of symptoms and the use of spirometry. However, these methods require long periods of assessment to determine whether patients show clinically relevant improvements after intervention. We therefore wanted to determine how existing clinical and laboratory measures change with COPD severity and identify disease markers that can serve as better endpoints for diagnosis and assessment of COPD progression and treatment effect.

METHODS

Using standard COPD keywords and terms, we searched PubMed, ISI Web of Science, and Cochrane Review databases for retrospective and prospective clinical studies published since 1966. We identified 652 studies (n = 146,255) from 1978 to September 2003 based on the availability of spirometric and demographic data, investigation of possible markers, absence of acute exacerbations and co-morbidities, and the withdrawal of standard COPD medication. Central tendencies and dispersions of subject baseline measures were collected according to study sample size, smoking status, and mild, moderate and severe COPD stages. A fixed effect meta-analysis was then conducted on each measure at various disease stages.

RESULTS

Arterial oxygen tension, sputum neutrophils and IL-8, and serum TNF-alpha and C-Reactive Protein showed a trend toward separation between COPD stages. Other measures such as pack-years and St George's Respiratory Questionnaire only distinguished between disease and disease-free states.

CONCLUSIONS

We observed little separation between disease stages for many measures used in COPD diagnosis and clinical trials. This demonstrates the poor sensitivity of such endpoints to define a patient's clinical status and to quantify treatment effect. Therefore, we recommend that longitudinal studies and disease modelling be the primary methods for assessing whether potential markers of disease progression can be used for COPD diagnosis and clinical trials.

Designing in vitro assay systems for hazard characterization. Basic strategies and related technical issues

Adverse effects of chemicals on humans are typically assessed following four steps: hazard identification, hazard characterization, exposure assessment and risk characterization. Hazard characterization is defined as the qualitative and/or quantitative evaluation of the nature of the adverse effects associated with biological, chemical and physical agents of interest. For chemical agents, hazard characterization is based on a series of in vitro and/or in vivo data obtained from mechanistic, kinetic and dose-response studies on the agent of concern, which are analyzed and integrated for extrapolation to eventually match human conditions. Thus, an accurate experimental design and the development of test methods capable of generating data relevant to hazard characterization are essential for the useful risk assessment of chemicals, including inhaled materials. It should, however, be stressed that hazard characterization has widely been limited to single chemicals. The hazard characterization of airborne mixtures therefore poses a new problem in toxicology, which calls for a novel approach to its scientific assessment. During the last three decades, a number of epidemiological and experimental studies have been conducted focusing on two kinds of inhaled complex mixtures, namely cigarette smoke and diesel exhausts. A new approach to the assessment of airborne complex mixtures may be elaborated through the appropriate, combined use of the findings of such studies. In this context, the present review article is intended to illustrate some basic strategies for and technical issues related to the hazard characterization of inhaled complex mixtures, thereby taking up representative epidemiological and experimental data from published papers on tobacco smoke.

Steroid-resistant Inflammation in a Rat Model of Chronic Obstructive Pulmonary Disease Is Associated with a Lack of Nuclear Factor-κB Pathway Activation

RATIONALE

Emphysema is one component of chronic obstructive pulmonary disease (COPD), a respiratory disease currently increasing in prevalence worldwide. The mainstay therapy adopted to treat patients with COPD is glucocorticoids; unfortunately, this treatment has limited impact on disease symptoms or underlying airway inflammation.

OBJECTIVE

There is an urgent need to develop therapies that modify both the underlying inflammation, thought to be involved in disease progression, and the structural changes in the emphysematous lung.

METHODS

We have characterized an elastase-driven model of experimental emphysema in the rat that demonstrates COPD-like airway inflammation and determined the impact of a clinically relevant glucocorticoid.

MEASUREMENTS AND MAIN RESULTS

We observed an increase in lung neutrophils, lymphomononuclear cells, mucus production, and inflammatory cytokines. Also present were increases in average air space area, which are associated with emphysema-like changes in lung function, such as increased residual volume and decreased flow; these increases in area were maintained for up to 10 weeks. In addition, we observed that elastase-induced airway neutrophilia is steroid resistant. Interestingly, the inflammation observed after elastase administration was found to be temporally associated with a lack of nuclear factor-kappaB pathway activation. This apparent nuclear factor-kappaB-independent inflammation may explain why treatment with a glucocorticoid was ineffective in this preclinical model and could suggest parallels in the steroid-resistant human disease.

CONCLUSION

We believe that this model, in addition to its suitability for testing therapies that may modify existing emphysema, could be useful in the search for new therapies to reduce the steroid-resistant airway inflammation evident in COPD.

Intravenous aminophylline in patients admitted to hospital with non-acidotic exacerbations of chronic obstructive pulmonary disease: a prospective randomised controlled trial

BACKGROUND

Intravenous aminophylline is commonly used in the treatment of exacerbations of chronic obstructive pulmonary disease (COPD), despite limited evidence for its efficacy and known risks of toxicity. We hypothesised that adding intravenous aminophylline to conventional treatment would not produce clinically important changes in the speed of spirometric or symptomatic recovery or shorten hospital stay in patients with exacerbations of COPD.

METHODS

Eighty patients admitted to hospital with non-acidotic exacerbations of COPD were recruited at admission to a randomised, double blind, placebo controlled study comparing intravenous aminophylline 0.5 mg/kg/hour after an appropriate loading dose with an equivalent volume of 0.9% saline. The primary outcome was the change in post-bronchodilator forced expiratory volume in 1 second (FEV(1)) over the first 5 days of the admission. Secondary end points were changes in self-reported breathlessness, arterial blood gas tensions, forced vital capacity (FVC), and length of hospital stay.

RESULTS

There was no difference in the post-bronchodilator FEV(1) over the first 5 days between the aminophylline and placebo groups. In the aminophylline group, 2 hours of treatment produced a small but significant rise in arterial pH (p = 0.001) and a fall in arterial carbon dioxide tension (p = 0.01) compared with placebo treatment. There were no differences in the severity of breathlessness, post-bronchodilator FVC, or length of hospital stay between the groups. Nausea was a more frequent side effect in the aminophylline group (46% v 22%; p<0.05), but palpitations and headache were noted equally in both groups.

CONCLUSIONS

Although intravenous aminophylline produced small improvements in acid-base balance, these did not influence the subsequent clinical course. No evidence was found for any clinically important additional effect of aminophylline treatment when used with high dose nebulised bronchodilators and oral corticosteroids. Given its known toxicity, we cannot therefore recommend the use of intravenous aminophylline in the treatment of non-acidotic COPD exacerbations.

Sputum eosinophilia and the short term response to inhaled mometasone in chronic obstructive pulmonary disease

BACKGROUND

An association between the sputum eosinophil count and the response to a 2 week course of prednisolone has previously been reported in patients with chronic obstructive pulmonary disease (COPD). Whether the response to inhaled corticosteroids is related to the presence of eosinophilic inflammation is unclear.

METHODS

A randomised, double blind, crossover trial of placebo and mometasone furoate (800 microg/day), each given for 6 weeks with a 4 week washout period, was performed in subjects with COPD treated with bronchodilator therapy only. Spirometric tests, symptom scores, chronic respiratory disease questionnaire (CRQ), and induced sputum were performed before and after each treatment phase.

RESULTS

Ninety five patients were recruited of which 60 were randomised. Overall there were no treatment associated changes in forced expiratory volume in 1 second (FEV(1)), total CRQ, or sputum characteristics. After stratification into tertiles by baseline eosinophil count, the net improvement in post-bronchodilator FEV(1) increased with mometasone compared with placebo progressively from the least to the most eosinophilic tertile. The mean change in post-bronchodilator FEV(1) with mometasone compared with placebo in the highest tertile was 0.11 l (95% CI 0.03 to 0.19). This improvement was not associated with a fall in the sputum eosinophil count.

CONCLUSIONS

An increased sputum eosinophil count is related to an improvement in post-bronchodilator FEV(1) following treatment with inhaled mometasone in COPD, but the improvement is not associated with a reduction in the sputum eosinophil count.

Effects of inhaled corticosteroids on sputum cell counts in stable chronic obstructive pulmonary disease: a systematic review and a meta-analysis

Background

Whether inhaled corticosteroids suppress airway inflammation in chronic obstructive pulmonary disease (COPD) remains controversial. We sought to determine the effects of inhaled corticosteroids on sputum indices of inflammation in stable COPD.

Methods

We searched MEDLINE, EMBASE, CINAHL, and the Cochrane Databases for randomized, controlled clinical trials that used induced sputum to evaluate the effect of inhaled corticosteroids in stable COPD. For each chosen study, we calculated the mean differences in the concentrations of sputum cells before and after treatment in both intervention and control groups. These values were then converted into standardized mean differences to accommodate the differences in patient selection, clinical treatment, and biochemical procedures that were employed across original studies. If significant heterogeneity was present (p < 0.10), then a random effects model was used to pool the original data. In the absence of significant heterogeneity, a fixed effects model was used.

Results

We identified six original studies that met the inclusion criteria (N = 162 participants). In studies with higher cumulative dose (≥ 60 mg) or longer duration of therapy (≥ 6 weeks), inhaled corticosteroids were uniformly effective in reducing the total cell, neutrophil, and lymphocyte counts. In contrast, studies with lower cumulative dose (< 60 mg) or shorter duration of therapy (< 6 weeks) did not demonstrate a favorable effect of inhaled corticosteroids on these sputum indices.

Conclusions

Our study suggests that prolonged therapy with inhaled corticosteroids is effective in reducing airway inflammation in stable COPD.

Are ICD-10 codes appropriate for performance assessment in asthma and COPD in general practice? Results of a cross sectional observational study

BACKGROUND

The increasing prevalence and impact of obstructive lung diseases and new insights, reflected in clinical guidelines, have led to concerns about the diagnosis and therapy of asthma and COPD in primary care. In Germany diagnoses written in medical records are used for reimbursement, which may influence physicians' documentation behaviour. For that reason it is unclear to what respect ICD-10 codes reflect the real problems of the patients in general practice. The aim of this study was to assess the appropriateness of the recorded diagnoses and to determine what diagnostic information is used to guide medical treatment.

METHODS

All patients with lower airway symptoms (n = 857) who had attended six general practices between January and June 2003 were included into this cross sectional observational study. Patients were selected from the computerised medical record systems, focusing on ICD-10-codes concerning lower airway diseases (J20-J22, J40-J47, J98 and R05). The performed diagnostic procedures and actual medication for each identified patient were extracted manually. Then we examined the associations between recorded diagnoses, diagnostic procedures and prescribed treatment for asthma and COPD in general practice.

RESULTS

Spirometry was used in 30% of the patients with a recorded diagnosis of asthma and in 58% of the patients with a recorded diagnosis of COPD. Logistic regression analysis showed an improved use of spirometry when inhaled corticosteroids were prescribed for asthma (OR = 5.2; CI 2.9-9.2) or COPD (OR = 4.7; CI 2.0-10.6). Spirometry was also used more often when sympathomimetics were prescribed (asthma: OR = 2.3; CI 1.2-4.2; COPD: OR = 4.1; CI 1.8-9.4).

CONCLUSIONS

This study revealed that spirometry was used more often when corticosteroids or sympathomimetics were prescribed. The findings suggest that treatment was based on diagnostic test results rather than on recorded diagnoses. The documented ICD-10 codes may not always reflect the real status of the patients. Thus medical care for asthma and COPD in general practice may be better than initially found on the basis of recorded diagnoses, although further improvement of practice patterns in asthma and COPD is still necessary.

Polymers of Z alpha1-antitrypsin co-localize with neutrophils in emphysematous alveoli and are chemotactic in vivo

The molecular mechanisms that cause emphysema are complex but most theories suggest that an excess of proteinases is a crucial requirement. This paradigm is exemplified by severe deficiency of the key anti-elastase within the lung: alpha(1)-antitrypsin. The Z mutant of alpha(1)-antitrypsin has a point mutation Glu342Lys in the hinge region of the molecule that renders it prone to intermolecular linkage and loop-sheet polymerization. Polymers of Z alpha(1)-antitrypsin aggregate within the liver leading to juvenile liver cirrhosis and the resultant plasma deficiency predisposes to premature emphysema. We show here that polymeric alpha(1)-anti-trypsin co-localizes with neutrophils in the alveoli of individuals with Z alpha(1)-antitrypsin-related emphysema. The significance of this finding is underscored by the excess of neutrophils in these individuals and the demonstration that polymers cause an influx of neutrophils when instilled into murine lungs. Polymers exert their effect directly on neutrophils rather than via inflammatory cytokines. These data provide an explanation for the accelerated tissue destruction that is characteristic of Z alpha(1)-antitrypsin-related emphysema. The transition of native Z alpha(1)-antitrypsin to polymers inactivates its anti-proteinase function, and also converts it to a proinflammatory stimulus. These findings may also explain the progression of emphysema in some individuals despite alpha(1)-antitrypsin replacement therapy.

Increased activity of matrix metalloproteinase-8 and matrix metalloproteinase-9 in induced sputum from patients with COPD

BACKGROUND

The increased expression of matrix metalloproteinases (MMPs) is considered to be a key factor in the development of COPD. Net MMP activity represents a tightly regulated process, which is not addressed by conventional investigation methods such as messenger RNA or protein expression. Yet, quantitative data on MMP activity in the airways of COPD patients are lacking.

METHODS

We used specific immunocapture assays to quantify the activity of MMP collagenase (ie, MMP-1, MMP-8, and MMP-13) and MMP gelatinase (ie, MMP-2 and MMP-9) in the induced sputum of COPD patients (17 patients; FEV(1), 56% predicted) and healthy smokers (17 subjects; FEV(1), 99% predicted).

RESULTS

Levels of total and active MMP-8 and MMP-9 were significantly increased in COPD patients vs control subjects, whereas MMP-1 activity levels were similar in both groups. The activity of MMP-2 and MMP-13 remained below the detection threshold of the assays. MMP-8 and MMP-9 activity were strongly related to neutrophilia in both groups, and the results of immunohistochemistry tests on sputum cytospins showed that MMP-9 was expressed in both alveolar macrophages and neutrophils, whereas MMP-8 expression was exclusively observed in neutrophils. A positive correlation was found between sputum MMP-8 and MMP-9 activity and the degree of airflow limitation.

CONCLUSION

We demonstrate increased MMP-8 and MMP-9 activity in the airway compartment of patients with mild-to-moderate COPD. This study provides further evidence of an impaired proteinase-antiproteinase balance in COPD patients.

Prospects for new drugs for chronic obstructive pulmonary disease

No currently available treatments have been shown to slow the progression of chronic obstructive pulmonary disease (COPD) or suppress the inflammation in small airways and lung parenchyma. However, several new treatments are in clinical development; some target the inflammatory process and others are directed against structural cells. A group of specific therapies are directed against the influx of inflammatory cells into the airways and lung parenchyma that occurs in COPD; these include agents directed against adhesion molecules and chemokines, as well as therapies to oppose tumour necrosis factor alpha and increase interleukin 10. Broad-range anti-inflammatory drugs are now in phase III development for COPD; they include inhibitors of phosphodiesterase 4. Other drugs that inhibit cell signalling include inhibitors of p38 mitogen-activated protein kinase, nuclear factor kappaB, and phosphoinositide-3-kinase gamma. More specific approaches are to give antioxidants, inhibitors of inducible nitric oxide synthase, and antagonists of leukotriene B4 receptor. Inhibitors of epidermal-growth-factor-receptor kinase and calcium-activated chloride channels have the potential to prevent overproduction of mucus. Therapy to inhibit fibrosis is being developed against transforming growth factor beta1 and protease-activated receptor 2. There is also a search for inhibitors of serine proteinases and matrix metalloproteinases to prevent lung destruction and the development of emphysema, as well as drugs such as retinoids that might even reverse this process. Effective delivery of drugs to the sites of disease in the peripheral lung is an important consideration, and there is a need for validated biomarkers and monitoring techniques in early clinical studies with new therapies for COPD.

Potent inhibition of human leukocyte elastase by 1,2,5-thiadiazolidin-3-one 1,1 dioxide-based sulfonamide derivatives

The design, synthesis, and in vitro biochemical evaluation of a class of mechanism-based inhibitors of human leukocyte elastase (HLE) that incorporate in their structure a 1,2,5-thiadiazolidin-3-one 1,1 dioxide scaffold with appropriate recognition and reactivity elements appended to it is described. The synthesized compounds were found to be efficient, time-dependent inhibitors of HLE. The interaction of the inhibitors with HLE is postulated to lead to the formation of a highly reactive N-sulfonyl imine (a Michael acceptor) that arises from an enzyme-induced sulfonamide fragmentation cascade. Subsequent reaction ultimately leads to the formation of a relatively stable acyl enzyme. The results cited herein demonstrate convincingly the superiority of the 1,2,5-thiadiazolidin-3-one 1,1 dioxide scaffold over other scaffolds (e.g., saccharin) in the design of inhibitors of (chymo)trypsin-like serine proteases.

[Acute exacerbation of COPD]

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) often develop into emergency situations that are associated with high morbidity and mortality. There is still a lack of a generally accepted definition for the risk stratification in AECOPD to guide an optimal diagnosis and treatment. In this article we propose a classification based on 4 degrees of severity, depending on whether outpatient treatment can be done by the patient himself or is provided by a physician and whether inpatient treatment is carried out on a general ward or on an intensive care unit. The pharmacological therapy of AECOPD relies on short acting bronchodilators, systemic corticosteroids and in case of purulent sputum on antibiotics. Longacting beta(2)-agonists or anticholinergics, theophyllin, mucolytic drugs or mechanical percussion to the chest by a physiotherapist have no proven value in the emergency treatment of AECOPD. In respiratory failure the use of oxygen therapy and non-invasive positive pressure ventilation (NIPPV) can often prevent the need for endotracheal intubation and controlled mechanical ventilation, thus preventing associated risks like the development of nosocomial pneumonia.