Authors: Felix Ratjen; Andrew Bush

Authors: David A. Zisman; Steven M. Kawut

Authors: Karen Wells; Manel Pladevall; Edward L. Peterson; Janis Campbell; Mingqun Wang; David E. Lanfear; L. Keoki Williams

Rationale: Adherence to inhaled corticosteroid (ICS) medication is known to be low overall, but tends to be lower among African-American patients when compared with white patients.

Objectives: To understand the factors that contribute to ICS adherence among African-American and white adults with asthma.

Methods: Eligible individuals had a prior diagnosis of asthma, one or more ICS prescriptions, and were members of a large health maintenance organization in southeast Michigan. Individuals were sent a survey that included questions about internal factors (e.g., patient beliefs, knowledge, and motivation) and external factors (e.g., socioeconomic status, barriers to care, social support, and stressors) potentially related to ICS adherence. Adherence was calculated using electronic prescription and fill data. Stepwise regression was used to identify factors associated with adherence before and after stratifying by race-ethnicity.

Measurements and Main Results: Surveys were returned by 1,006 (56.3%) of 1,787 eligible patients. Adjusting for internal factors, but not external factors, diminished the relationship between race-ethnicity and ICS adherence. Among African-American patients, readiness to take ICS medication was the only internal or external factor significantly associated with ICS adherence; it explained 5.6% of the variance in adherence. Among white patients, perceived ICS necessity, ICS knowledge, doctors being perceived as the source of asthma control, and readiness to take medication were the internal factors associated with ICS adherence; these accounted for 19.8% of the variance in adherence.

Conclusions: Factors associated with ICS adherence appear to differ between African-American and white patients, suggesting that group-specific approaches are needed to improve adherence.

Authors: Jiansheng Zhou; C. Roland Wolf; Colin J. Henderson; Yeping Cai; Philip G. Board; Paul S. Foster; Dianne C. Webb

Rationale: Although epidemiological studies have linked asthma susceptibility and severity to polymorphisms in human glutathione transferase Pi (GSTP) 1, there is no direct evidence for a functional involvement of GSTP1 in processes that are pathognomic of asthma.

Objectives: To examine the role of GSTP1 in modulating the development of allergic airways disease.

Methods: Allergic airways disease was induced in wild-type (WT) and Gstp-null mice employing both acute and chronic models. Eosinophilia, goblet cells, and remodeling were quantified by histological assessment; respiratory function was determined using invasive methods. ELISA was used to evaluate Th2 cytokines, eotaxin, and phospho-c-Jun. Gstp1/2 expression was quantified by reverse transcriptase–polymerase chain reaction.

Measurements and Main Results: Compared with allergic WT mice, eosinophilia, goblet cell hyperplasia, airway remodeling, lung resistance, and IL-5 were enhanced in allergic Gstp-null mice. However, the protective efficacy of GSTP1 was mouse-strain dependent, and associated with inherent variation in expression of Gstp1. Although elevated levels of phospho-c-Jun were detected in Gstp-null mice, treatment of WT mice with a GSTP/c-Jun N-terminal kinase (JNK) inhibitory peptide enhanced phospho-c-Jun and significantly attenuated allergic responses.

Conclusions: GSTP1 attenuates the severity of allergic airways disease. However, the efficacy of GSTP1 correlated with mouse strain-dependent variation in Gstp1 expression. Although GSTP1 attenuated c-Jun phosphorylation, treatment with a GSTP/JNK inhibitory peptide revealed an inverse relationship between c-Jun phosphorylation and allergic responses, indicating that the mechanism by which GSTP attenuates allergic responses is not dependent on the JNK/c-Jun axis. Our data, together with epidemiological evidence, suggest variation in expression and/or function of this protein is an important determinant in asthma pathophysiology.

Authors: Philipp Eickhoff; Arschang Valipour; Dora Kiss; Martin Schreder; Leyla Cekici; Kora Geyer; Robab Kohansal; Otto C. Burghuber

Rationale: Impaired vascular reactivity is an important factor in the pathogenesis of cardiovascular disease.

Objectives: We sought to assess vascular reactivity in patients with chronic obstructive pulmonary disease (COPD) and respective control subjects, and to investigate the relation between vascular function and airflow obstruction and systemic inflammation.

Methods: We studied 60 patients with stable COPD; 20 smokers with normal lung function matched for age, sex, and body weight; and 20 similarly matched nonsmokers. Patients with cardiovascular comorbidities were excluded. The endothelium-dependent and endothelium-independent function of the vasculature was measured using flow-mediated and nitrogen-mediated dilation of the brachial artery, respectively. Systemic inflammatory markers, including C-reactive protein, fibrinogen, and interleukin (IL)-6, were determined in serum.

Measurements and Main Results: Both flow-mediated and nitrogen-mediated dilation of the brachial artery were significantly lower in patients with stable COPD than in smoking and nonsmoking control subjects. Levels of inflammatory mediators such as IL-6 and fibrinogen were higher in patients than they were in control subjects. In patients with COPD, stepwise multiple regression analysis showed that age, sex, baseline brachial artery diameter, C-reactive protein level, leukocyte count, blood glucose level, and percentage of predicted forced expiratory volume in 1 s were independent predictors of flow-mediated dilation. There was no relation between flow-mediated dilation and pack-years of smoking. Baseline brachial artery diameter was the only independent predictor of nitrogen-mediated dilation in patients with COPD.

Conclusions: Both endothelium-dependent and endothelium-independent vasodilation is significantly impaired in patients with stable COPD. Airflow obstruction and systemic inflammation may increase the risk of cardiovascular disease in patients with COPD.

Authors: Karen Maes; Dries Testelmans; Pascal Cadot; Keith DeRuisseau; Scott K. Powers; Marc Decramer; Ghislaine Gayan-Ramirez

Rationale: Mechanical ventilation is known to induce ventilator-induced diaphragm dysfunction. Patients submitted to mechanical ventilation often receive massive doses of corticosteroids that may cause further deterioration of diaphragm function.

Objectives: To examine whether the combination of 24 hours of controlled mechanical ventilation with corticosteroid administration would exacerbate ventilator-induced diaphragm dysfunction.

Methods: Rats were randomly assigned to a group submitted to 24 hours of controlled mechanical ventilation receiving an intramuscular injection of saline or 80 mg/kg methylprednisolone, a group submitted to 24 hours of spontaneous breathing receiving saline, or methylprednisolone and a control group.

Measurements and Main Results: The diaphragm force–frequency curve was shifted downward in the mechanical ventilation group, but this deleterious effect was prevented when corticosteroids were administered. Diaphragm cross-sectional area of type I fibers was similarly decreased in both mechanical ventilation groups while atrophy of type IIx/b fibers was attenuated after corticosteroid administration. The mechanical ventilation-induced reduction in diaphragm MyoD and myogenin protein expression was attenuated after corticosteroids. Plasma cytokine levels were unchanged while diaphragm lipid hydroperoxides were similarly increased in both mechanical ventilation groups. Diaphragmatic calpain activity was significantly increased in the mechanical ventilation group, but calpain activation was abated with corticosteroid administration. Inverse correlations were found between calpain activity and diaphragm force.

Conclusions: A single high dose of methylprednisolone combined with controlled mechanical ventilation protected diaphragm function from the deleterious effects of controlled mechanical ventilation. Inhibition of the calpain system is most likely the mechanism by which corticosteroids induce this protective effect.

Authors: Lynne A. Murray; Darryl A. Knight; Laura McAlonan; Rochelle Argentieri; Amrita Joshi; Furquan Shaheen; Mark Cunningham; Lena Alexopolou; Richard A. Flavell; Robert T. Sarisky; Cory M. Hogaboam

Rationale: Acute respiratory distress syndrome (ARDS) manifests clinically as a consequence of septic and/or traumatic injury in the lung. Oxygen therapy remains a major therapeutic intervention in ARDS, but this can contribute further to lung damage. Patients with ARDS are highly susceptible to viral infection and it may be due to altered Toll-like receptor (TLR) expression.

Objectives: To evaluate the role of TLR3 in ARDS.

Methods: TLR3 expression and signaling was determined in airway epithelial cells after in vitro hyperoxia challenge. Using a murine model of hyperoxia-induced lung injury, the role of TLR3 was determined using either TLR3-gene deficient mice or a specific neutralizing antibody directed to TLR3.

Measurements and Main Results: Increased TLR3 expression was observed in airway epithelial cells from patients with ARDS. Further, hyperoxic conditions alone were a major stimulus for increased TLR3 expression and activation in cultured human epithelial cells. Interestingly, TLR3^−/− mice exhibited less acute lung injury, activation of apoptotic cascades, and extracellular matrix deposition after 5 days of 80% oxygen compared with wild-type (TLR3^+/+) mice under the same conditions. Administration of a monoclonal anti-TLR3 antibody to TLR3^+/+ mice exposed to hyperoxic conditions likewise protected these mice from lung injury and inflammation.

Conclusions: The potential for redundancy in function as well as cross-talk between distinct TLRs may indeed contribute to whether the inflammatory cascade can be effectively disrupted once signaling has been initiated. Together, these data show that TLR3 has a major role in the development of ARDS-like pathology in the absence of a viral pathogen.

Authors: Barry M. Linnane; Graham L. Hall; Gary Nolan; Siobhan Brennan; Stephen M. Stick; Peter D. Sly; Colin F. Robertson; Philip J. Robinson; Peter J. Franklin; Stephen W. Turner; Sarath C. Ranganathan

Rationale: Progressive lung damage in cystic fibrosis (CF) starts in infancy, and early detection may aid preventative strategies.

Objectives: To measure lung function in infants with CF diagnosed by newborn screening and describe its association with pulmonary infection and inflammation.

Methods: Infants with CF (n = 68, 6 weeks to 30 months of age) and healthy infants without CF (n = 49) were studied. Forced vital capacity, FEV0.5, and forced expiratory flows at 75% of exhaled vital capacity (FEF75) were measured using the raised-volume rapid thoracoabdominal compression technique. Forty-eight hours later, infants with CF had bronchoalveolar lavage (BAL) for assessment of pulmonary infection and inflammation.

Measurements and Main Results: In the CF group, the deficit in FEV0.5 z score increased by −0.77 (95% confidence interval, −1.14 to −0.41; P < 0.001) with each year of age. The mean FEV0.5 z score did not differ between infants with CF and healthy control subjects less than 6 months of age (−0.06 and 0.02, respectively; P = 0.87). However, the mean FEV0.5 z score was lower by 1.15 in infants with CF who were older than 6 months of age compared with healthy infants (P < 0.001). FVC and FEF75 followed a similar pattern. Pulmonary infection and inflammation in BAL samples did not explain the lung function results.

Conclusions: Lung function, measured by forced expiration, is normal in infants with CF at the time of diagnosis by newborn screening but is diminished in older infants. These findings suggest that in CF the optimal timing of therapeutic interventions aimed at preserving lung function may be within the first 6 months of life.

Authors: Zhe Zhou; Diana Treis; Susanne C. Schubert; Maria Harm; Jolanthe Schatterny; Stephanie Hirtz; Julia Duerr; Richard C. Boucher; Marcus A. Mall

Rationale: Increased airway Na⁺ absorption mediated by epithelial Na⁺ channels (ENaC) is a characteristic abnormality in the pathogenesis of cystic fibrosis (CF) lung disease. However, inhalation therapy with the ENaC blocker amiloride did not have therapeutic benefits in patients with CF with established lung disease.

Objectives: We hypothesized that preventive inhibition of increased Na⁺ absorption in a structurally normal lung may be required for effective therapy of CF lung disease in vivo, and that therapeutic effects of late amiloride intervention may be impeded by the chronic disease process.

Methods: To test this hypothesis in vivo, we used the βENaC-overexpression mouse as a model of CF lung disease and determined therapeutic effects of preventive versus late amiloride therapy on survival, airway mucus plugging, chronic bronchitis, and airway remodeling.

Measurements and Main Results: We show that early intervention, i.e., from the first day of life, with the intranasal administration of amiloride significantly reduced pulmonary mortality, airway mucus obstruction, epithelial necrosis, goblet cell metaplasia, and airway inflammation in βENaC-overexpressing mice. In contrast, consistent with previous human trials in patients with CF, amiloride administration did not have benefits if treatment was started after the development of CF-like lung disease in βENaC-overexpressing mice.

Conclusions: We conclude that preventive inhibition of increased airway Na⁺ absorption provides an effective therapy for CF-like lung disease in vivo. These results suggest that amiloride therapy may be an effective preventive therapy for patients with CF if initiated early in life before the onset of lung disease.

Authors: Richard B. Hubbard; Chris Smith; Ivan Le Jeune; Jonathan Gribbin; Andrew W. Fogarty

Rationale: Previous studies have suggested that people with idiopathic pulmonary fibrosis (IPF) may be at increased risk of vascular disease.

Objectives: To quantify the risk of cardiovascular disease before and after a diagnosis of IPF.

Methods: We used computerized primary care data from the Health Improvement Network to quantify the relative risk of having a cardiovascular event (acute coronary syndrome, angina, atrial fibrillation, deep-vein thrombosis, and cerebrovascular accident) either before or after having a diagnosis of IPF in comparison to age, sex, and community-matched general population control subjects.

Measurements and Main Results: Our study included 920 incident case subjects of IPF (mean age at diagnosis, 71 yr; 62% male) and 3,593 matched control subjects. There was an increased risk of acute coronary syndrome (odds ratio [OR], 1.53; 95% confidence interval [CI], 1.15–2.03), angina (OR, 1.84; 95% CI, 1.48–2.29) and deep-vein thrombosis (OR, 1.98; 95% CI, 1.13–3.48) in the period before the diagnosis of IPF. During the follow-up period, there was a marked increased risk of acute coronary syndrome (rate ratio [RR], 3.14; 95%CI, 2.02–4.87) and deep-vein thrombosis (RR, 3.39; 95% CI, 1.57–7.28). None of these estimates were confounded by smoking habit or modified by age or sex.

Conclusions: People with IPF have an increased risk of vascular disease in comparison with the general population. This effect is most marked for acute coronary syndrome and deep-vein thrombosis after the diagnosis of IPF has been made.

Authors: Philip H. Quanjer; Gerard J. J. M. Borsboom; Jana Kivastik; Peter J. F. M. Merkus; John L. Hankinson; Danny Houthuijs; Bert Brunekreef; Gabriele Ihorst; Joachim Kühr

Rationale: Single and serial spirometric data are commonly compared with predicted values to assess pulmonary function and normal lung growth.

Objectives: Do reference equations adequately describe pulmonary function in a population and in growing individuals?

Methods: We applied five sets of reference equations with appropriate age ranges to cross-sectional data of FEV1, FVC, and FEV1/FVC from the United States, Estonia, and The Netherlands (1,487 boys and 1,340 girls, 6 to 18 years of age), and to serial measurements in Dutch (430 girls and 769 boys, 6 to 19 years of age) and in German and Austrian children (1,305 girls and 1,303 boys, 6 to 13 years of age).

Measurements and Main Results: Compared with reference equations from Polgar and Zapletal, cross-sectional FEV1 and FVC declined between the ages of 6 and 12 and then increased, leading to a spurious change of up to 25% predicted; this pattern was most pronounced in boys. In cross-sectional data this trend was much weaker when using reference equations from Hankinson, Quanjer, and Stanojevic, and these equations provided a good fit from the age of 12 upward. In longitudinal data (i.e., within individuals), the trend was more pronounced for FEV1 in boys than in girls. No set of equations provided a satisfactory fit in the lower limits of normal, but Hankinson and Stanojevic equations performed best.

Conclusions: Spirometric reference equations that use only height for predicting pulmonary function are unsuitable for describing the progression of pulmonary function. Those that incorporate height and age demonstrate some discrepancy with longitudinal data. Failure to take these spurious trends into account leads to significant errors in estimating the natural course of respiratory disease, in allocating patients to treatment groups, or in assessing long-term effects of drug intervention in school children and adolescents.

Authors: Umadevi Sajjan; Qiong Wang; Ying Zhao; Dieter C. Gruenert; Marc B. Hershenson

Rationale: Secondary bacterial infection following rhinovirus (RV) infection has been recognized in chronic obstructive pulmonary disease.

Objectives: We sought to understand mechanisms by which RV infection facilitates secondary bacterial infection.

Methods: Primary human airway epithelial cells grown at air–liquid interface and human bronchial epithelial (16HBE14o-) cells grown as polarized monolayers were infected apically with RV. Transmigration of bacteria (nontypeable Haemophilus influenzae and others) was assessed by colony counting and transmission electron microscopy. Transepithelial resistance (RT) was measured by using a voltmeter. The distribution of zona occludins (ZO)-1 was determined by immunohistochemistry and immunoblotting.

Measurements and Main Results: Epithelial cells infected with RV showed 2-log more bound bacteria than sham-infected cultures, and bacteria were recovered from the basolateral media of RV- but not sham-infected cells. Infection of polarized airway epithelial cell cultures with RV for 24 hours caused a significant decrease in RT without causing cell death or apoptosis. Ultraviolet-treated RV did not decrease RT, suggesting a requirement for viral replication. Reduced RT was associated with increased paracellular permeability, as determined by flux of fluorescein isothiocyanate (FITC)-inulin. Neutralizing antibodies to tumor necrosis factor (TNF)-α, IFN-γ and IL-1β reversed corresponding cytokine-induced reductions in RT but not that induced by RV, indicating that the RV effect is independent of these proinflammatory cytokines. Confocal microscopy and immunoblotting revealed the loss of ZO-1 from tight junction complexes in RV-infected cells. Intranasal inoculation of mice with RV1B also caused the loss of ZO-1 from the bronchial epithelium tight junctions in vivo.

Conclusions: RV facilitates binding, translocation, and persistence of bacteria by disrupting airway epithelial barrier function.

Author: Eduardo Hernández-Garduño

Author: Roland Diel

Authors: Timothy D. Mickleborough; Martin R. Lindley

Authors: Zara Pogson; John Britton; Andrew Fogarty