Long-term cigarette smoke exposure in a mouse model of ciliated epithelial cell function

Exposure to cigarette smoke is associated with airway epithelial mucus cell hyperplasia and a decrease in cilia and ciliated cells. Few models have addressed the long-term effects of chronic cigarette smoke exposure on ciliated epithelial cells. Our previous in vitro studies showed that cigarette smoke decreases ciliary beat frequency (CBF) via the activation of protein kinase C (PKC). We hypothesized that chronic cigarette smoke exposure in an in vivo model would decrease airway epithelial cell ciliary beating in a PKC-dependent manner. We exposed C57BL/6 mice to whole-body cigarette smoke 2 hours/day, 5 days/week for up to 1 year. Tracheal epithelial cell CBF and the number of motile cells were measured after necropsy in cut tracheal rings, using high-speed digital video microscopy. Tracheal epithelial PKC was assayed according to direct kinase activity. At 6 weeks and 3 months of smoke exposure, the baseline CBF was slightly elevated (~1 Hz) versus control mice, with no change in β-agonist-stimulated CBF between control mice and cigarette smoke-exposed mice. By 6 months of smoke exposure, the baseline CBF was significantly decreased (2-3 Hz) versus control mice, and a β-agonist failed to stimulate increased CBF. The loss of β-agonist-increased CBF continued at 9 months and 12 months of smoke exposure, and the baseline CBF was significantly decreased to less than one third of the control rate. In addition to CBF, ciliated cell numbers significantly decreased in response to smoke over time, with a significant loss of tracheal ciliated cells occurring between 6 and 12 months. In parallel with the slowing of CBF, significant PKC activation from cytosol to the membrane of tracheal epithelial cells was detected in mice exposed to smoke for 6-12 months.

Development of predictive models for airflow obstruction in alpha-1-antitrypsin deficiency

Alpha-1-antitrypsin deficiency is a genetic condition associated with severe, early-onset chronic obstructive pulmonary disease (COPD). However, there is significant variability in lung function impairment among persons with the protease inhibitor ZZ genotype. Early identification of persons at highest risk of developing lung disease could be beneficial in guiding monitoring and treatment decisions. Using a multicenter, family-based study sample (2002-2005) of 372 persons with the protease inhibitor ZZ genotype, the authors developed prediction models for forced expiratory volume in 1 second (FEV(1)) and the presence of severe COPD using demographic, clinical, and genetic variables. Half of the data sample was used for model development, and the other half was used for model validation. In the training sample, variables found to be predictive of both FEV(1) and severe COPD were age, sex, pack-years of smoking, bronchodilator responsiveness, chronic bronchitis symptoms, and index case status. In the validation sample, the predictive model for FEV(1) explained 50% of the variance in FEV(1), and the model for severe COPD exhibited excellent discrimination (c statistic = 0.88).

Statins inhibit matrix metalloproteinase release from human lung fibroblasts

Pleiotropic effects of statins have been reported to include inhibition of matrix metalloproteinase (MMP) release from macrophages and endothelial cells. We evaluated whether statins would inhibit MMP release from human lung fibroblasts, which play a major role in remodelling processes. Monolayer and three-dimensional (3D) collagen gel cultures of fibroblasts were used. Cytokines (tumour necrosis factor-alpha and interleukin-1alpha) were used to induce MMP release and mRNA expression. Collagen degradation induced by cytokines and neutrophil elastase (NE) was evaluated by quantifying hydroxyproline. Atorvastatin inhibited MMP-1 and -3 release and mRNA expression in both culture systems. Similar results were obtained with simvastatin and fluvastatin. In 3D cultures where cytokines also stimulated MMP-9 release, atorvastatin also inhibited MMP-9 release. In 3D cultures, cytokines together with NE induced collagen degradation, which was also inhibited by atorvastatin. The effect of atorvastatin was reversed by mevalonate and geranylgeranyl-pyrophosphate but not by farnesyl-pyrophosphate. The current data suggest that statins may modulate remodelling processes mediated by fibroblasts by inhibiting MMP release.

Budesonide and the risk of pneumonia: a meta-analysis of individual patient data

BACKGROUND

Concern is continuing about increased risk of pneumonia in patients with chronic obstructive pulmonary disease (COPD) who use inhaled corticosteroids. We aimed to establish the effects of inhaled budesonide on the risk of pneumonia in such patients.

METHODS

We pooled patient data from seven large clinical trials of inhaled budesonide (320-1280 mug/day), with or without formoterol, versus control regimen (placebo or formoterol alone) in patients with stable COPD and at least 6 months of follow-up. The primary analysis compared treatment groups for the risk of pneumonia as an adverse event or serious adverse event during the trial or within 15 days of the trial end. Cox proportional hazards regression was used to analyse the data on an intention-to-treat basis. Data were adjusted for patients' age, sex, smoking status, body-mass index, and postbronchodilator percent of predicted forced expiratory volume in 1 s (FEV(1)).

FINDINGS

We analysed data from 7042 patients, of whom 3801 were on inhaled budesonide and 3241 were on control treatment, with 5212 patient-years of exposure to treatment. We recorded no significant difference between treatment groups for the occurrence of pneumonia as an adverse event (3% [n=122 patients] vs 3% [n=103]; adjusted hazard ratio 1.05, 95% CI 0.81-1.37) or a serious adverse event (1% [n=53] vs 2% [n=50]; 0.92, 0.62-1.35), or for time to pneumonia as an adverse event (log-rank test 0.94) or a serious adverse event (0.61). Increasing age and decreasing percent of predicted FEV(1) were the only two variables that were significantly associated with occurrence of pneumonia as an adverse event or a serious adverse event.

INTERPRETATION

Budesonide treatment for 12 months does not increase the risk of pneumonia in patients with COPD during that time and therefore is safe for clinical use in such patients.

FUNDING

Michael Smith Foundation for Health Research.

Efficacy and tolerability of budesonide/formoterol in one hydrofluoroalkane pressurized metered-dose inhaler in patients with chronic obstructive pulmonary disease: results from a 1-year randomized controlled clinical trial

Background: Combination therapy with a long-acting bronchodilator and an inhaled corticosteroid (ICS) is recommended in patients with chronic obstructive pulmonary disease (COPD) who have frequent exacerbations. The efficacy and tolerability of the combination of budesonide/formoterol have been demonstrated in patients with COPD when administered via the dry powder inhaler (DPI) in a 1-year study and when administered via the hydrofluoroalkane (HFA) pressurized metered-dose inhaler (pMDI) in a 6-month study.

Objective: This study assessed the long-term efficacy and tolerability of budesonide/formoterol HFA pMDI in patients with moderate to very severe COPD.

Methods: This was a 12-month, randomized, double-blind, double-dummy, parallel-group, active- and placebo-controlled, multicentre study (NCT00206167) of 1964 patients aged ≥40 years with moderate to very severe COPD conducted from 2005 to 2007 at 237 sites in the US, Europe and Mexico. After 2 weeks of treatment based on previous therapy (ICSs, short-acting bronchodilators allowed), patients received one of the following treatments twice daily: budesonide/formoterol pMDI 160/4.5 μg × two inhalations (320/9 μg); budesonide/formoterol pMDI 80/4.5 μg × two inhalations (160/9 μg); formoterol DPI 4.5 μg × two inhalations (9 μg); or placebo.

Main outcome measures: The co-primary efficacy variables were pre-dose forced expiratory volume in 1 second (FEV₁) and 1-hour post-dose FEV₁.

Results: Budesonide/formoterol 320/9 μg demonstrated greater improvements in pre-dose FEV₁ versus formoterol (p = 0.008), and both budesonide/formoterol doses demonstrated greater improvements in 1-hour post-dose FEV₁ versus placebo (p < 0.001). The rate of COPD exacerbations was lower in both budesonide/formoterol groups compared with formoterol and placebo (p ≤ 0.004). Both budesonide/formoterol doses were more effective than placebo (p ≤ 0.006) for controlling dyspnoea and improving health status (St George’s Respiratory Questionnaire). All treatments were generally well tolerated. The incidence of pneumonia was not different for active (3.4–4.0%) and placebo (5.0%) groups.

Conclusions: Budesonide/formoterol pMDI (320/9 μg and 160/9 μg) improved pulmonary function and reduced symptoms and exacerbations over 1 year in patients with moderate to very severe COPD. Only budesonide/formoterol pMDI 320/9 μg demonstrated greater efficacy for both co-primary variables compared with formoterol DPI 9 μg. Both budesonide/formoterol pMDI dosages were well tolerated relative to formoterol and placebo.

N-acetyl-L-cysteine inhibits TGF-beta1-induced profibrotic responses in fibroblasts

BACKGROUND

Excessive production of TGF-beta(1) plays a key role in the tissue remodeling or fibrotic process observed in bronchial asthma, chronic pulmonary disease (COPD), and idiopathic pulmonary fibrosis (IPF). TGF-beta(1) has been reported to decrease the intracellular glutathione level and stimulate the production of reactive oxygen species.

OBJECTIVES

The aim of this study was to evaluate whether the antioxidant N-acetyl-l-cysteine (NAC) can affect TGF-beta(1)-mediated tissue remodeling in fibroblasts or modulate the production of fibronectin and vascular endothelial growth factor (VEGF) which are believed to be important mediators of tissue repair and remodeling.

METHODS

To accomplish this, human fetal lung fibroblasts (HFL-1) were used to assess the effect of NAC on the TGF-beta(1)-mediated contraction of floating gels and the TGF-beta(1)-induced mediator production. In addition, the effect of NAC on the TGF-beta(1)-induced differentiation to myofibroblasts was evaluated by assessing alpha-smooth muscle actin (alpha-SMA) expression.

RESULTS

NAC significantly abolished the TGF-beta(1)-augmented gel contraction (at 3mM, gel size 63.4+/-2.6% vs. 39.1+/-4.1%; p<0.01) compared with control in a concentration-dependent manner. NAC also significantly inhibited the TGF-beta(1)-augmented fibronectin (p<0.01) and VEGF (p<0.01) production in the media of both the three-dimensional gel and monolayer culture. Furthermore, NAC reversed the TGF-beta(1)-stimulated alpha-SMA expression (p<0.01).

CONCLUSION

These results suggest that NAC can affect the TGF-beta(1)-induced tissue remodeling or fibrotic process in vitro.

PDE4 inhibitors roflumilast and rolipram augment PGE2 inhibition of TGF-{beta}1-stimulated fibroblasts

Fibrotic diseases are characterized by the accumulation of extracellular matrix together with distortion and disruption of tissue architecture. Phosphodiesterase (PDE)4 inhibitors, by preventing the breakdown of cAMP, can inhibit fibroblast functions and may be able to mitigate tissue remodeling. Transforming growth factor (TGF)-beta1, a mediator of fibrosis, can potentially modulate cAMP by altering PGE(2) metabolism. The present study assessed whether PDE4 inhibitors functionally antagonize the profibrotic activity of fibroblasts stimulated by TGF-beta1. The PDE4 inhibitors roflumilast and rolipram both inhibited fibroblast-mediated contraction of three-dimensional collagen gels and fibroblast chemotaxis toward fibronectin in the widely studied human fetal lung fibroblast strain HFL-1 and several strains of fibroblasts from adult human lung. Roflumilast was approximately 10-fold more potent than rolipram. There was a trend for PDE4 inhibitors to inhibit more in the presence of TGF-beta1 (0.05 < P < 0.08). The effect of the PDE4 inhibitors was mediated through cAMP-stimulated protein kinase A (PKA), although a PKA-independent effect on gel contraction was also observed. The effect of PDE4 inhibitors depended on fibroblast production of PGE(2) and TGF-beta1-induced PGE(2) production. PDE4 inhibitors together with TGF-beta1 resulted in augmented PGE(2) production together with increased expression of COX mRNA and protein. The present study supports the concept that PDE4 inhibitors may attenuate fibroblast activities that can lead to fibrosis and that PDE4 inhibitors may be particularly effective in the presence of TGF-beta1-induced fibroblast stimulation.

A genome-wide association study in chronic obstructive pulmonary disease (COPD): identification of two major susceptibility loci

There is considerable variability in the susceptibility of smokers to develop chronic obstructive pulmonary disease (COPD). The only known genetic risk factor is severe deficiency of alpha(1)-antitrypsin, which is present in 1-2% of individuals with COPD. We conducted a genome-wide association study (GWAS) in a homogenous case-control cohort from Bergen, Norway (823 COPD cases and 810 smoking controls) and evaluated the top 100 single nucleotide polymorphisms (SNPs) in the family-based International COPD Genetics Network (ICGN; 1891 Caucasian individuals from 606 pedigrees) study. The polymorphisms that showed replication were further evaluated in 389 subjects from the US National Emphysema Treatment Trial (NETT) and 472 controls from the Normative Aging Study (NAS) and then in a fourth cohort of 949 individuals from 127 extended pedigrees from the Boston Early-Onset COPD population. Logistic regression models with adjustments of covariates were used to analyze the case-control populations. Family-based association analyses were conducted for a diagnosis of COPD and lung function in the family populations. Two SNPs at the alpha-nicotinic acetylcholine receptor (CHRNA 3/5) locus were identified in the genome-wide association study. They showed unambiguous replication in the ICGN family-based analysis and in the NETT case-control analysis with combined p-values of 1.48 x 10(-10), (rs8034191) and 5.74 x 10(-10) (rs1051730). Furthermore, these SNPs were significantly associated with lung function in both the ICGN and Boston Early-Onset COPD populations. The C allele of the rs8034191 SNP was estimated to have a population attributable risk for COPD of 12.2%. The association of hedgehog interacting protein (HHIP) locus on chromosome 4 was also consistently replicated, but did not reach genome-wide significance levels. Genome-wide significant association of the HHIP locus with lung function was identified in the Framingham Heart study (Wilk et al., companion article in this issue of PLoS Genetics; doi:10.1371/journal.pgen.1000429). The CHRNA 3/5 and the HHIP loci make a significant contribution to the risk of COPD. CHRNA3/5 is the same locus that has been implicated in the risk of lung cancer.

Efficacy and safety of budesonide and formoterol in one pressurized metered-dose inhaler in patients with moderate to very severe chronic obstructive pulmonary disease: results of a 6-month randomized clinical trial

BACKGROUND

The combination of an inhaled corticosteroid (ICS) and a long-acting bronchodilator is recommended in the treatment of patients with chronic obstructive pulmonary disease (COPD) who have frequent exacerbations. Budesonide/formoterol dry powder inhaler (DPI) has demonstrated efficacy and tolerability in patients with COPD.

OBJECTIVE

To evaluate the efficacy and tolerability of budesonide/formoterol administered via one hydrofluoroalkane pressurized metered-dose inhaler (pMDI) in patients with COPD.

METHODS

This was a 6-month, randomized, double-blind, double-dummy, placebo-controlled, parallel-group, multicentre study (NCT00206154) of 1704 patients aged > or =40 years with moderate to very severe COPD conducted in 194 centres in the US, Czech Republic, the Netherlands, Poland and South Africa. After 2 weeks of treatment based on previous therapy (ICSs and short-acting bronchodilators allowed during the run-in period), patients received one of the following treatments administered twice daily: budesonide/formoterol pMDI 160/4.5 microg x two inhalations (320/9 microg); budesonide/formoterol pMDI 80/4.5 microg x two inhalations (160/9 microg); budesonide pMDI 160 microg x two inhalations (320 microg) plus formoterol DPI 4.5 microg x two inhalations (9 microg); budesonide pMDI 160 microg x two inhalations (320 microg); formoterol DPI 4.5 microg x two inhalations (9 microg); or placebo.

MAIN OUTCOME MEASURES

The co-primary efficacy variables were pre-dose forced expiratory volume in 1 second (FEV(1)) and 1-hour post-dose FEV(1).

RESULTS

Budesonide/formoterol 320/9 microg demonstrated significantly greater improvements in pre-dose FEV(1) versus formoterol (p = 0.026; pre-specified primary comparator) and 1-hour post-dose FEV(1) versus budesonide (p < 0.001; pre-specified primary comparator); budesonide/formoterol 160/9 microg demonstrated significantly greater improvements versus budesonide (p < 0.001) for 1-hour post-dose FEV(1) but not versus formoterol for pre-dose FEV(1). Dyspnoea (measured using the Breathlessness Diary) and health-related quality-of-life (HR-QOL) scores (based on the St George's Respiratory Questionnaire total score) were significantly improved with both dosage strengths of budesonide/formoterol compared with budesonide, formoterol and placebo (p < or = 0.044 for all). Although not powered a priori for comparisons, the number of exacerbations per patient-treatment year requiring treatment with oral corticosteroids and/or hospitalization was numerically (20-25%) lower with the budesonide-containing treatments (0.710-0.884) versus formoterol (1.098) and placebo (1.110). This result was driven by the exacerbations requiring treatment with oral corticosteroids (79-120 events). The number of exacerbations resulting in hospitalization was very low across treatment groups (11-22); the number per patient-treatment year was significantly different for budesonide/formoterol 320/9 microg (0.158) versus other treatment groups (0.081-0.108) except budesonide/formoterol 160/9 microg (0.139), and for budesonide/formoterol 160/9 microg versus formoterol (0.081) [p < or = 0.05]. All treatments were generally well tolerated. The incidence of individual non-fatal serious adverse events was similar across all treatment groups, except COPD, which was highest in the budesonide/formoterol 320/9 microg group (6.1%) and lowest in the budesonide (3.6%) and formoterol (3.9%) groups, with a range of 4.3-4.6% in the budesonide/formoterol 160/9 microg, budesonide plus formoterol and placebo groups. Budesonide/formoterol had a safety profile comparable with that of the monocomponents and placebo. There was no increase in the incidence of pneumonia in the active treatment groups relative to placebo.

CONCLUSIONS

Budesonide/formoterol pMDI 320/9 microg demonstrated significantly greater efficacy for pulmonary function on both co-primary endpoints versus the pre-specified comparators (formoterol DPI 9 microg for pre-dose FEV(1) and budesonide pMDI 320 microg for 1-hour post-dose FEV(1)). Budesonide/formoterol pMDI 160/9 microg demonstrated significantly greater efficacy for 1-hour post-dose FEV(1) versus budesonide pMDI 320 microg. Dyspnoea scores and HR-QOL were significantly improved with both budesonide/formoterol pMDI dosage strengths versus both monocomponents and placebo. Both budesonide/formoterol pMDI dosage strengths were well tolerated relative to the monocomponents and placebo.

Heritability of lung function in severe alpha-1 antitrypsin deficiency

Severe alpha-1 antitrypsin (AAT) deficiency is a proven genetic risk factor for COPD, but there is marked variation in the development of COPD among AAT deficient subjects. To investigate familial aggregation of lung function in subjects with AAT deficiency, we estimated heritability for forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity (FVC) in 378 AAT deficient subjects from 167 families in the AAT Genetic Modifiers Study; all subjects were verified homozygous for the Z AAT deficiency allele. Heritability was evaluated for models that included and excluded an ascertainment correction, as well as for models that excluded, included and were stratified by a cigarette smoking covariate. In models without an ascertainment correction, and in all models without a covariate for smoking, no evidence for familial aggregation of lung function was observed. In models conditioned on the index proband with covariates for smoking, post-bronchodilator FEV1/FVC demonstrated significant heritability (0.26 +/- 0.14, p = 0.03). When we limited the analysis to subjects with a smoking history, post-bronchodilator FEV1 demonstrated significant heritability (0.47 +/- 0.21, p = 0.02). Severity rate phenotypes were also assessed as potential phenotypes for genetic modifier studies. Significant heritability was found with all age-of-onset threshold models that included smoking and ascertainment adjustments. Using the t-distribution, the heritability estimates ranged from 0.43 to 0.64, depending on the age-of-onset of FEV1 decline used for the severity rate calculation. Correction for ascertainment and consideration of gene-by-smoking interactions will be crucial for the identification of genes that may modify susceptibility for COPD in families with AAT deficiency.

The many "small COPDs": COPD should be an orphan disease

COPD is one of the most common causes of morbidity and mortality. Perhaps paradoxically, COPD also should be an orphan disease. Importantly, this could advance the development of treatments for COPD. There are two criteria for orphan status in the United States. Most widely known is the criterion of < 200,000 affected individuals; however, secondarily, is the impossibility for development costs to be recovered during the patent life of a product. COPD should qualify for the first criterion if the various conditions that comprise COPD are regarded separately. The subphenotyping of COPD into separate groups based on mechanism sets the stage for the rational development of therapeutics. In addition, many candidate treatments may alter the natural history of COPD. Testing them, however, will require large studies for a duration that will compromise the commercial life of any resulting product. Orphan status, therefore, could facilitate the development of treatments for both phenotypic subsets of COPD patients as well as aid the development of agents to alter the natural history of the disease. Post-drug approval regulations could require that agents approved under the orphan provisions are prospectively monitored, assuring that rigorous longitudinal data are generated. This approach could encourage the pharmaceutical industry to stratify studies based on a more detailed characterization of study subjects at baseline, thus approaching "many small COPDs" instead of a single large and heterogeneous COPD. This strategy may help to address the increasing burden that COPD presents and for which no novel clinical class of treatment has been introduced for 30 years.

Lung fibroblast repair functions in patients with chronic obstructive pulmonary disease are altered by multiple mechanisms

RATIONALE

Fibroblasts are believed to be the major cells responsible for the production and maintenance of extracellular matrix. Alterations in fibroblast functional capacity, therefore, could play a role in the pathogenesis of pulmonary emphysema, which is characterized by inadequate maintenance of tissue structure.

OBJECTIVES

To evaluate the hypothesis that deficient fibroblast repair characterizes cells obtained from individuals with chronic obstructive pulmonary disease (COPD) compared with control subjects.

METHODS

Fibroblasts were cultured from lung tissue obtained from individuals undergoing thoracotomy and were characterized in vitro.

MEASUREMENTS AND MAIN RESULTS

Fibroblasts from individuals with COPD, defined by reduced FEV(1), manifested reduced chemotaxis toward fibronectin and reduced contraction of three-dimensional collagen gels, two bioassays associated with fibroblast repair function. At least two mechanisms appear to account for these differences. Prostaglandin E (PGE), a known inhibitor of fibroblast repair functions, was produced in increased amount by fibroblasts from subjects with COPD, which also expressed increased amounts of the receptors EP2 and EP4, both of which signal through cyclic AMP. Incubation of fibroblasts with indomethacin or with the PKA inhibitor KT-5720 partially restored COPD subject fibroblast function. In addition, fibroblasts from subjects with COPD produced more transforming growth factor (TGF)-beta1, but manifested reduced response to TGF-beta1. The functional alterations in fibroblasts correlated with both lung function assessed by FEV(1) and, for the data available, with severity of emphysema assessed by Dl(CO).

CONCLUSIONS

Fibroblasts from individuals with COPD have reduced capability to sustain tissue repair, which suggests that this may be one mechanism that contributes to the development of emphysema.