Contributors to diffusion impairment in HIV-infected persons

Abnormal diffusing capacity is common in HIV-infected individuals, including never smokers. Aetiologies for diffusing capacity impairment in HIV are not understood, particularly in those without a history of cigarette smoking. Our study was a cross-sectional analysis of 158 HIV-infected individuals without acute respiratory symptoms or infection with the aim to determine associations between a diffusing capacity of the lung for carbon monoxide (D(LCO)) % predicted and participant demographics, pulmonary spirometric measures (forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity), radiographic emphysema (fraction of lung voxels < -950 Hounsfield units), pulmonary vascular/cardiovascular disease (echocardiographic tricuspid regurgitant jet velocity, N-terminal pro-brain natriuretic peptide) and airway inflammation (induced sputum cell counts), stratified by history of smoking. The mean D(LCO) was 65.9% predicted, and 55 (34.8%) participants had a significantly reduced D(LCO) (<60% predicted). Lower D(LCO) % predicted in ever-smokers was associated with lower post-bronchodilator FEV1 % predicted (p<0.001) and greater radiographic emphysema (p=0.001). In never-smokers, mean±SD D(LCO) was 72.7±13.4% predicted, and D(LCO) correlated with post-bronchodilator FEV1 (p=0.02), sputum neutrophils (p=0.03) and sputum lymphocytes (p=0.009), but not radiographic emphysema. Airway obstruction, emphysema and inflammation influence D(LCO) in HIV. Never-smokers may have a unique phenotype of diffusing capacity impairment. The interaction of multiple factors may account for the pervasive nature of diffusing capacity impairment in HIV infection.

Down-regulated peroxisome proliferator-activated receptor γ (PPARγ) in lung epithelial cells promotes a PPARγ agonist-reversible proinflammatory phenotype in chronic obstructive pulmonary disease (COPD)

Chronic obstructive pulmonary disease (COPD) is a progressive inflammatory condition and a leading cause of death, with no available cure. We assessed the actions in pulmonary epithelial cells of peroxisome proliferator-activated receptor γ (PPARγ), a nuclear hormone receptor with anti-inflammatory effects, whose role in COPD is largely unknown. We found that PPARγ was down-regulated in lung tissue and epithelial cells of COPD patients, via both reduced expression and phosphorylation-mediated inhibition, whereas pro-inflammatory nuclear factor-κB (NF-κB) activity was increased. Cigarette smoking is the main risk factor for COPD, and exposing airway epithelial cells to cigarette smoke extract (CSE) likewise down-regulated PPARγ and activated NF-κB. CSE also down-regulated and post-translationally inhibited the glucocorticoid receptor (GR-α) and histone deacetylase 2 (HDAC2), a corepressor important for glucocorticoid action and whose down-regulation is thought to cause glucocorticoid insensitivity in COPD. Treating epithelial cells with synthetic (rosiglitazone) or endogenous (10-nitro-oleic acid) PPARγ agonists strongly up-regulated PPARγ expression and activity, suppressed CSE-induced production and secretion of inflammatory cytokines, and reversed its activation of NF-κB by inhibiting the IκB kinase pathway and by promoting direct inhibitory binding of PPARγ to NF-κB. In contrast, PPARγ knockdown via siRNA augmented CSE-induced chemokine release and decreases in HDAC activity, suggesting a potential anti-inflammatory role of endogenous PPARγ. The results imply that down-regulation of pulmonary epithelial PPARγ by cigarette smoke promotes inflammatory pathways and diminishes glucocorticoid responsiveness, thereby contributing to COPD pathogenesis, and further suggest that PPARγ agonists may be useful for COPD treatment.

Considerations and pitfalls in phenotyping and reclassification of chronic obstructive pulmonary disease

As the clinical and research focus of chronic obstructive pulmonary disease (COPD) evolves from regarding obstructive lung disease as a single disease entity to recognizing the complexity of disease expression, the importance of COPD phenotyping rises to the forefront. The reclassification of COPD holds both prognostic and therapeutic implications but does not come without issues that may complicate classification efforts. In this review, we discuss the significance of refining the definition of the term phenotype, consider the impact of variations in cohort severity and attribute mix, account for the contrast of longitudinal vs cross-sectional cohort analysis, recognize the differing criteria used to define disease traits along with the nuances of combining cohorts, and identify the interaction of covariates as we advance in the field of COPD phenotyping.

Plasma B lymphocyte stimulator and B cell differentiation in idiopathic pulmonary fibrosis patients

We hypothesized B cells are involved in the pathogenesis of idiopathic pulmonary fibrosis (IPF), a progressive, restrictive lung disease that is refractory to glucocorticoids and other nonspecific therapies, and almost invariably lethal. Accordingly, we sought to identify clinically associated B cell-related abnormalities in these patients. Phenotypes of circulating B cells were characterized by flow cytometry. Intrapulmonary processes were evaluated by immunohistochemistry. Plasma B lymphocyte stimulating factor (BLyS) was assayed by ELISA. Circulating B cells of IPF subjects were more Ag differentiated, with greater plasmablast proportions (3.1 ± 0.8%) than in normal controls (1.3 ± 0.3%) (p < 0.03), and the extent of this differentiation correlated with IPF patient lung volumes (r = 0.44, p < 0.03). CD20(+) B cell aggregates, diffuse parenchymal and perivascular immune complexes, and complement depositions were all prevalent in IPF lungs, but much less prominent or absent in normal lungs. Plasma concentrations of BLyS, an obligate factor for B cell survival and differentiation, were significantly greater (p < 0.0001) in 110 IPF (2.05 ± 0.05 ng/ml) than among 53 normal (1.40 ± 0.04 ng/ml) and 90 chronic obstructive pulmonary disease subjects (1.59 ± 0.05 ng/ml). BLyS levels were uniquely correlated among IPF patients with pulmonary artery pressures (r = 0.58, p < 0.0001). The 25% of IPF subjects with the greatest BLyS values also had diminished 1-y survival (46 ± 11%), compared with those with lesser BLyS concentrations (81 ± 5%) (hazard ratio = 4.0, 95% confidence interval = 1.8-8.7, p = 0.0002). Abnormalities of B cells and BLyS are common in IPF patients, and highly associated with disease manifestations and patient outcomes. These findings have implications regarding IPF pathogenesis and illuminate the potential for novel treatment regimens that specifically target B cells in patients with this lung disease.

Patients with idiopathic pulmonary fibrosis with antibodies to heat shock protein 70 have poor prognoses

RATIONALE

Diverse autoantibodies are present in most patients with idiopathic pulmonary fibrosis (IPF). We hypothesized that specific autoantibodies may associate with IPF manifestations.

OBJECTIVES

To identify clinically relevant, antigen-specific immune responses in patients with IPF.

METHODS

Autoantibodies were detected by immunoblots and ELISA. Intrapulmonary immune processes were evaluated by immunohistochemistry. Anti-heat shock protein 70 (HSP70) IgG was isolated from plasma by immunoaffinity. Flow cytometry was used for leukocyte functional studies.

MEASUREMENTS AND MAIN RESULTS

HSP70 was identified as a potential IPF autoantigen in discovery assays. Anti-HSP70 IgG autoantibodies were detected by immunoblots in 3% of 60 control subjects versus 25% of a cross-sectional IPF cohort (n = 122) (P = 0.0004), one-half the patients with IPF who died (P = 0.008), and 70% of those with acute exacerbations (P = 0.0005). Anti-HSP70 autoantibodies in patients with IPF were significantly associated with HLA allele biases, greater subsequent FVC reductions (P = 0.0004), and lesser 1-year survival (40 ± 10% vs. 80 ± 5%; hazard ratio = 4.2; 95% confidence interval, 2.0-8.6; P < 0.0001). HSP70 protein, antigen-antibody complexes, and complement were prevalent in IPF lungs. HSP70 protein was an autoantigen for IPF CD4 T cells, inducing lymphocyte proliferation (P = 0.004) and IL-4 production (P = 0.01). IPF anti-HSP70 autoantibodies activated monocytes (P = 0.009) and increased monocyte IL-8 production (P = 0.049). ELISA confirmed the association between anti-HSP70 autoreactivity and IPF outcome. Anti-HSP70 autoantibodies were also found in patients with other interstitial lung diseases but were not associated with their clinical progression.

CONCLUSIONS

Patients with IPF with anti-HSP70 autoantibodies have more near-term lung function deterioration and mortality. These findings suggest antigen-specific immunoassays could provide useful clinical information in individual patients with IPF and may have implications for understanding IPF progression.

Paired inspiratory-expiratory chest CT scans to assess for small airways disease in COPD

Background

Gas trapping quantified on chest CT scans has been proposed as a surrogate for small airway disease in COPD. We sought to determine if measurements using paired inspiratory and expiratory CT scans may be better able to separate gas trapping due to emphysema from gas trapping due to small airway disease.

Methods

Smokers with and without COPD from the COPDGene Study underwent inspiratory and expiratory chest CT scans. Emphysema was quantified by the percent of lung with attenuation < −950HU on inspiratory CT. Four gas trapping measures were defined: (1) Exp₋₈₅₆, the percent of lung < −856HU on expiratory imaging; (2) E/I MLA, the ratio of expiratory to inspiratory mean lung attenuation; (3) RVC_856-950, the difference between expiratory and inspiratory lung volumes with attenuation between −856 and −950 HU; and (4) Residuals from the regression of Exp₋₈₅₆ on percent emphysema.

Results

In 8517 subjects with complete data, Exp₋₈₅₆ was highly correlated with emphysema. The measures based on paired inspiratory and expiratory CT scans were less strongly correlated with emphysema. Exp₋₈₅₆, E/I MLA and RVC_856-950 were predictive of spirometry, exercise capacity and quality of life in all subjects and in subjects without emphysema. In subjects with severe emphysema, E/I MLA and RVC_856-950 showed the highest correlations with clinical variables.

Conclusions

Quantitative measures based on paired inspiratory and expiratory chest CT scans can be used as markers of small airway disease in smokers with and without COPD, but this will require that future studies acquire both inspiratory and expiratory CT scans.

Optimizing the 6-min walk test as a measure of exercise capacity in COPD

BACKGROUND

It is uncertain whether the effort and expense of performing a second walk for the 6-min walk test improves test performance. Hence, we attempted to quantify the improvement in 6-min walk distance if an additional walk were to be performed.

METHODS

We studied patients consecutively enrolled into the National Emphysema Treatment Trial who prior to randomization and after 6 to 10 weeks of pulmonary rehabilitation performed two 6-min walks on consecutive days (N = 396). Patients also performed two 6-min walks at 6-month follow-up after randomization to lung volume reduction surgery (n = 74) or optimal medical therapy (n = 64). We compared change in the first walk distance to change in the second, average-of-two, and best-of-two walk distances.

RESULTS

Compared with the change in the first walk distance, change in the average-of-two and best-of-two walk distances had better validity and precision. Specifically, 6 months after randomization to lung volume reduction surgery, changes in the average-of-two (r = 0.66 vs r = 0.58, P = .01) and best-of-two walk distances (r = 0.67 vs r = 0.58, P = .04) better correlated with the change in maximal exercise capacity (ie, better validity). Additionally, the variance of change was 14% to 25% less for the average-of-two walk distances and 14% to 33% less for the best-of-two walk distances than the variance of change in the single walk distance, indicating better precision.

CONCLUSIONS

Adding a second walk to the 6-min walk test significantly improves its performance in measuring response to a therapeutic intervention, improves the validity of COPD clinical trials, and would result in a 14% to 33% reduction in sample size requirements. Hence, it should be strongly considered by clinicians and researchers as an outcome measure for therapeutic interventions in patients with COPD.

A combinatorial F box protein directed pathway controls TRAF adaptor stability to regulate inflammation

Uncontrolled activation of tumor necrosis factor receptor-associated factor (TRAF) proteins may result in profound tissue injury by linking surface signals to cytokine release. Here we show that a ubiquitin E3 ligase component, Fbxo3, potently stimulates cytokine secretion from human inflammatory cells by destabilizing a sentinel TRAF inhibitor, Fbxl2. Fbxo3 and TRAF protein in circulation positively correlated with cytokine responses in septic subjects and we furthermore identified a hypofunctional Fbxo3 human polymorphism. A small molecule inhibitor targeting Fbxo3 was sufficient to lessen severity of cytokine-driven inflammation in several murine disease models. These studies identify a pathway of innate immunity that may characterize subjects with altered immune responses during critical illness or provide a basis for therapeutic intervention targeting TRAF protein abundance.

The relationship between pulmonary emphysema and kidney function in smokers

BACKGROUND

It has been reported that the prevalence of kidney dysfunction may be increased in patients exposed to tobacco with airflow obstruction. We hypothesized that kidney dysfunction would associate with emphysema rather than with airflow obstruction measured by the FEV₁.

METHODS

Five hundred eight current and former smokers completed a chest CT scan, pulmonary function tests, medical questionnaires, and measurement of serum creatinine. Glomerular filtration rates (eGFRs) were estimated using the method of the Chronic Kidney Disease Epidemiology Collaboration. Quantitative determinants of emphysema and airway dimension were measured from multidetector chest CT scans.

RESULTS

The mean age was 66 ± 7 years, and mean eGFR was 101 ± 22 mL/min/1.73 m². Univariate and multivariate analysis showed a significant association between radiographically measured emphysema and eGFR: Participants with 10% more emphysema had an eGFR that was lower by 4.4 mL/min/1.73 m² (P = .01), independent of airflow obstruction (FEV₁), age, sex, race, height, BMI, diabetes mellitus, hypertension, coronary artery disease, patient-reported dyspnea, pack-years of smoking, and current smoking. There was no association between eGFR and either FEV₁ or quantitative CT scan measures of airway dimension.

CONCLUSIONS

More severe emphysema, rather than airflow obstruction, is associated with kidney dysfunction in tobacco smokers, independent of common risk factors for kidney disease. This finding adds to recent observations of associations between emphysema and comorbidities of COPD, including osteoporosis and lung cancer, which are independent of the traditional measure of reduced FEV₁. The mechanisms and clinical implications of kidney dysfunction in patients with emphysema need further investigation.

Computerized identification of airway wall in CT examinations using a 3D active surface evolution approach

Airway diseases (e.g., asthma, emphysema, and chronic bronchitis) are extremely common worldwide. Any morphological variations (abnormalities) of airways may physically change airflow and ultimately affect the ability of the lungs in gas exchange. In this study, we describe a novel algorithm aimed to automatically identify airway walls depicted on CT images. The underlying idea is to place a three-dimensional (3D) surface model within airway regions and thereafter allow this model to evolve (deform) under predefined external and internal forces automatically to the location where these forces reach a state of balance. By taking advantage of the geometric and the density characteristics of airway walls, the evolution procedure is performed in a distance gradient field and ultimately stops at regions with the highest contrast. The performance of this scheme was quantitatively evaluated from several perspectives. First, we assessed the accuracy of the developed scheme using a dedicated lung phantom in airway wall estimation and compared it with the traditional full-width at half maximum (FWHM) method. The phantom study shows that the developed scheme has an error ranging from 0.04 mm to 0.36 mm, which is much smaller than the FWHM method with an error ranging from 0.16 mm to 0.84 mm. Second, we compared the results obtained by the developed scheme with those manually delineated by an experienced (>30 years) radiologist on clinical chest CT examinations, showing a mean difference of 0.084 mm. In particular, the sensitivity of the scheme to different reconstruction kernels was evaluated on real chest CT examinations. For the 'lung', 'bone' and 'standard' kernels, the average airway wall thicknesses computed by the developed scheme were 1.302 mm, 1.333 mm and 1.339 mm, respectively. Our preliminary experiments showed that the scheme had a reasonable accuracy in airway wall estimation. For a clinical chest CT examination, it took around 4 min for this scheme to identify the inner and outer airway walls on a modern PC.

Three-dimensional airway tree architecture and pulmonary function

RATIONALE AND OBJECTIVES

The airway tree is a primary conductive structure, and airways' morphologic characteristics, or variations thereof, may have an impact on airflow, thereby affecting pulmonary function. The objective of this study was to investigate the correlation between airway tree architecture, as depicted on computed tomography, and pulmonary function.

MATERIALS AND METHODS

A total of 548 chest computed tomographic examinations acquired on different patients at full inspiration were included in this study. The patients were enrolled in a study of chronic obstructive pulmonary disease (Specialized Center for Clinically Oriented Research) and underwent pulmonary function testing in addition to computed tomographic examinations. A fully automated airway tree segmentation algorithm was used to extract the three-dimensional airway tree from each examination. Using a skeletonization algorithm, airway tree volume-normalized architectural measures, including total airway length, branch count, and trachea length, were computed. Correlations between airway tree measurements with pulmonary function testing parameters and chronic obstructive pulmonary disease severity in terms of the Global Initiative for Obstructive Lung Disease classification were computed using Spearman's rank correlations.

RESULTS

Non-normalized total airway volume and trachea length were associated (P < .01) with lung capacity measures (ie, functional residual capacity, total lung capacity, inspiratory capacity, vital capacity, residual volume, and forced expiratory vital capacity). Spearman's correlation coefficients ranged from 0.27 to 0.55 (P < .01). With the exception of trachea length, all normalized architecture-based measures (ie, total airway volume, total airway length, and total branch count) had statistically significant associations with the lung function measures (forced expiratory volume in 1 second and the ratio of forced expiratory volume in 1 second to forced expiratory vital capacity), and adjusted volume was associated with all three respiratory impedance measures (lung reactance at 5 Hz, lung resistance at 5 Hz, and lung resistance at 20 Hz), and adjusted branch count was associated with all respiratory impedance measures but lung resistance at 20 Hz. When normalized for lung volume, all airway architectural measures were statistically significantly associated with chronic obstructive pulmonary disease severity, with Spearman's correlation coefficients ranging from -0.338 to -0.546 (P < .01).

CONCLUSIONS

Despite the large variability in anatomic characteristics of the airway tree across subjects, architecture-based measures demonstrated statistically significant associations (P < .01) with nearly all pulmonary function testing measures, as well as with disease severity.

Optimal threshold in CT quantification of emphysema

OBJECTIVES

To determine the optimal threshold by quantitatively assessing the extent of emphysema at the level of the entire lung and at the level of individual lobes using a large, diverse dataset of computed tomography (CT) examinations.

METHODS

This study comprises 573 chest CT examinations acquired from subjects with different levels of airway obstruction (222 none, 83 mild, 141 moderate, 63 severe and 64 very severe). The extent of emphysema was quantified using the percentage of the low attenuation area (LAA%) divided by the total lung or lobe volume(s). The correlations between the extent of emphysema, and pulmonary functions and the five-category classification were assessed using Pearson and Spearman's correlation coefficients, respectively. When quantifying emphysema using a density mask, a wide range of thresholds from -850 to -1,000 HU were used.

RESULTS

The highest correlations of LAA% with the five-category classification and PFT measures ranged from -925 to -965 HU for each individual lobe and the entire lung. However, the differences between the highest correlations and those obtained at -950 HU are relatively small.

CONCLUSION

Although there are variations in the optimal cut-off thresholds for individual lobes, the single threshold of -950 HU is still an acceptable threshold for density-based emphysema quantification.

Relationship between lung function impairment and health-related quality of life in COPD and interstitial lung disease

BACKGROUND

Health-related quality-of-life (HRQL) measures have been correlated with lung function in patients with COPD and interstitial lung disease (ILD). However, different pathophysiologic mechanisms may influence how these distinct diseases affect HRQL, resulting in differing HRQL by pulmonary diagnosis among patients with similar severity of ventilatory impairment.

METHODS

The National Heart, Lung, and Blood Institute Lung Tissue Research Consortium provided data on well-characterized participants with COPD (n = 576) and ILD (n = 405) at four clinical sites. Using multiple linear regression, we examined the effects of FEV₁ (% predicted) and diagnosis (ILD vs COPD) on HRQL scores, including total St. George Respiratory Questionnaire (SGRQ) scores and Short Form-12 (SF-12) physical component summary (PCS) and mental component summary (MCS) scores.

RESULTS

Participants with ILD had, on average, higher SGRQ scores (15.33 points; 95% CI, 12.46-18.19; P <.001) and lower SF-12 PCS scores (-4.73 points; 95% CI, -6.31 to -3.14; P <.001) compared with patients with COPD with similar FEV₁ % predicted values, indicating worse HRQL. The specific diagnosis also modified the effect of FEV₁ on the total SGRQ score (P = .003) and the SF-12 PCS score (P = .03). There was no relationship between lung function and SF-12 MCS scores.

CONCLUSIONS

HRQL scores were worse for patients with ILD compared with patients with COPD with similar degrees of ventilatory impairment. Differences in dyspnea mechanism or in the rate of disease progression may account for these differences in HRQL.

Long-term comparative immunogenicity of protein conjugate and free polysaccharide pneumococcal vaccines in chronic obstructive pulmonary disease

BACKGROUND

Although the 23-valent pneumococcal polysaccharide vaccine (PPSV23) protects against invasive disease in young healthy persons, randomized controlled trials in chronic obstructive pulmonary disease (COPD) have demonstrated no benefit in the intention-to-treat population. We previously reported that the 7-valent diphtheria-conjugated pneumococcal polysaccharide vaccine (PCV7) is safe and induced greater serotype-specific immunoglobulin G (IgG) and functional antibody than did PPSV23 1 month after vaccination. We hypothesized that these advantages would persist at 1 and 2 years.

METHODS

One hundred eighty-one patients with moderate to severe COPD were randomized to receive PPSV23 (n = 90) or PCV7 (1.0 mL; n = 91). We measured IgG by enzyme-linked immunosorbent assay and assessed functional antibody activity by a standardized opsonophagocytosis assay, reported as a killing index (OPK). We determined differences in IgG and OPK between vaccine groups at 1 and 2 years.

RESULTS

Relative to PPSV23, PCV7 induced greater OPK at both 1 and 2 years for 6 of 7 serotypes (not 19F). This response was statistically greater for 5 of 7 serotypes at 1 year and 4 of 7 at 2 years. Comparable differences in IgG were observed but were less often statistically significant. Despite meeting Centers for Disease Control and Prevention criteria for PPSV23 administration, almost 50% of individuals had never been vaccinated. No differences in the frequency of acute exacerbations, pneumonia, or hospitalization were observed.

CONCLUSIONS

PCV7 induces a greater functional antibody response than PPSV23 in patients with COPD that persists for 2 years after vaccination. This superior functional response supports testing of conjugate vaccination in studies examining clinical end points.

CLINICAL TRIALS REGISTRATION

NCT00457977.

Comprehensive clinical and molecular analysis of 12 families with type 1 recessive cutis laxa

Autosomal recessive cutis laxa type I (ARCL type I) is characterized by generalized cutis laxa with pulmonary emphysema and/or vascular complications. Rarely, mutations can be identified in FBLN4 or FBLN5. Recently, LTBP4 mutations have been implicated in a similar phenotype. Studying FBLN4, FBLN5, and LTBP4 in 12 families with ARCL type I, we found bi-allelic FBLN5 mutations in two probands, whereas nine probands harbored biallelic mutations in LTBP4. FBLN5 and LTBP4 mutations cause a very similar phenotype associated with severe pulmonary emphysema, in the absence of vascular tortuosity or aneurysms. Gastrointestinal and genitourinary tract involvement seems to be more severe in patients with LTBP4 mutations. Functional studies showed that most premature termination mutations in LTBP4 result in severely reduced mRNA and protein levels. This correlated with increased transforming growth factor-beta (TGFβ) activity. However, one mutation, c.4127dupC, escaped nonsense-mediated decay. The corresponding mutant protein (p.Arg1377Alafs(*) 27) showed reduced colocalization with fibronectin, leading to an abnormal morphology of microfibrils in fibroblast cultures, while retaining normal TGFβ activity. We conclude that LTBP4 mutations cause disease through both loss of function and gain of function mechanisms.

Cardiopulmonary function in individuals with HIV infection in the antiretroviral therapy era

OBJECTIVE

To determine relationship of echocardiographic measures of pulmonary hypertension to lung function and inflammatory biomarkers in HIV-infected individuals.

DESIGN

Cross-sectional study of 116 HIV-infected outpatients.

METHODS

Doppler-echocardiography and pulmonary function testing were performed. Induced sputum and plasma cytokines, sputum cell counts and differentials, markers of peripheral T-cell activation, and serum N-terminal pro-brain natriuretic peptide (NT-proBNP) were measured. Univariate and multivariate analyses determined relationship of echocardiographic variables to pulmonary function, inflammation, and NT-proBNP.

RESULTS

Mean estimated pulmonary artery systolic pressure (PASP) was 34.3 mmHg (SD 6.9) and mean tricuspid regurgitant jet velocity (TRV) was 2.5 m/s (SD 0.32). Eighteen participants (15.5%) had PASP of at least 40 mmHg, and nine (7.8%) had TRV of at least 3.0 m/s. Elevated TRV was significantly associated with CD4 cell counts below 200 cells/μl and higher log HIV-RNA levels. Forced expiratory volume in 1 s (FEV(1)) percentage predicted, FEV(1)/forced vital capacity, and diffusing capacity for carbon monoxide (DLco) percentage predicted were significantly lower in those with elevated PASP or TRV. Sputum interleukin-8, peripheral interleukin-8, peripheral interferon-γ levels, and CD8(+) T-cell expression of CD69(+) were associated with increasing PASP and TRV. Log NT-proBNP was significantly higher with increasing PASP and TRV. Left ventricular function was not associated with PASP or TRV.

CONCLUSION

Echocardiographic manifestations of pulmonary hypertension are common in HIV and are associated with respiratory symptoms, more advanced HIV disease, airway obstruction, abnormal DLco, and systemic and pulmonary inflammation. Pulmonary hypertension and chronic obstructive pulmonary disease coexist in HIV and may arise secondary to common inflammatory mechanisms.

Asthma diagnosis and airway bronchodilator response in HIV-infected patients

BACKGROUND

Despite the high prevalence of respiratory symptoms and obstructive lung disease in HIV-infected subjects, the prevalence of bronchodilator reversibility (BDR) and asthma has not been systematically studied during the era of combination antiretroviral therapy (ART).

OBJECTIVE

We sought to determine the prevalence of asthma diagnosis and related pulmonary function abnormalities in an HIV-infected cohort and to identify potential mechanisms.

METHODS

We performed a cross-sectional analysis of 223 HIV-infected subjects with data on respiratory symptoms and diagnoses, pulmonary function, sputum cell counts, and asthma-related cytokines and chemokines in serum/sputum.

RESULTS

Doctor-diagnosed asthma was present in 46 (20.6%), and BDR (≥200 mL and ≥12% increase in FEV(1) or forced vital capacity) was present in 20 (9.0%) participants. Pulmonary symptoms and function were worse in those with doctor-diagnosed asthma. Doctor-diagnosed asthma was independently associated with female sex (P = .04), body mass index of greater than 29.6 kg/m(2) (vs <29.6 kg/m(2), P = .03), history of bacterial or Pneumocystis pneumonia (P = .01), and not currently taking ART (P = .04) and in univariate analysis with parental history of asthma (n = 180, P = .004). High sputum eosinophil percentages (>2.3% based on the highest decile) were more likely in those with doctor-diagnosed asthma (P = .02) or BDR (P = .02). Doctor-diagnosed asthma tended to be more common with high sputum IL-4 (P = .02) and RANTES (P = .02) levels, whereas BDR was associated with high plasma macrophage inflammatory protein 1α (P = .002) and sputum macrophage inflammatory protein 1β (P = .001) levels.

CONCLUSION

Asthma diagnosis and BDR are prevalent in an HIV-infected outpatient cohort, and associations with family history, obesity, allergic inflammation, prior infection, absence of ART, and increased HIV-stimulated cytokines suggest possible mechanisms of HIV-associated asthma.

Interstitial lung abnormalities and reduced exercise capacity

RATIONALE

The relationship between interstitial lung abnormalities (ILA) and exercise capacity has not been comprehensively evaluated.

OBJECTIVES

To assess the validity of the 6-minute walk test in subjects with ILA, and to examine the association between ILA and 6-minute walk distance (6MWD).

METHODS

Spearman correlation coefficients were used to assess the strength of the relationships between 6MWD and relevant measures of dyspnea, health-related quality of life, and pulmonary function in a cohort of 2,416 people who smoke from the COPDGene study. Unadjusted and adjusted linear and logistic regression models were used to assess the strength of the association between ILA and 6MWD.

MEASUREMENTS AND MAIN RESULTS

In all subjects, and in those with ILA, 6MWD in COPDGene was associated with relevant clinical and physiologic measures. The mean 6MWD in COPDGene subjects with ILA was 386 m (SD, 128 m), and 82% and 19% of subjects with ILA had 6MWDs less than or equal to 500 and 250 m, respectively. ILA was associated with a reduced 6MWD in univariate (-30 m; 95% confidence interval, -50 to -10; P = 0.004) and multivariate models (-19 m; 95% confidence interval, -33 to -5; P = 0.008). Compared with subjects without ILA, subjects with ILA had an 80% and 77% increase in their odds to have a walk distance limited to less than or equal to 500 and 250 m, respectively. Although these findings were dependent on ILA subtype, they were not limited to those with COPD.

CONCLUSIONS

Our study demonstrates that ILA is associated with measurable decrements in the 6MWD of people who smoke. Clinical trial registered with www.clinicaltrials.gov (NCT 00608764).

Outcomes of noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease in the United States, 1998-2008

RATIONALE

The patterns and outcomes of noninvasive, positive-pressure ventilation (NIPPV) use in patients hospitalized for acute exacerbations of chronic obstructive pulmonary disease (COPD) nationwide are unknown.

OBJECTIVES

To determine the prevalence and trends of noninvasive ventilation for acute COPD.

METHODS

We used data from the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample to assess the pattern and outcomes of NIPPV use for acute exacerbations of COPD from 1998 to 2008.

MEASUREMENTS AND MAIN RESULTS

An estimated 7,511,267 admissions for acute exacerbations occurred from 1998 to 2008. There was a 462% increase in NIPPV use (from 1.0 to 4.5% of all admissions) and a 42% decline in invasive mechanical ventilation (IMV) use (from 6.0 to 3.5% of all admissions) during these years. This was accompanied by an increase in the size of a small cohort of patients requiring transition from NIPPV to IMV. In-hospital mortality in this group appeared to be worsening over time. By 2008, these patients had a high mortality rate (29.3%), which represented 61% higher odds of death compared with patients directly placed on IMV (95% confidence interval, 24-109%) and 677% greater odds of death compared with patients treated with NIPPV alone (95% confidence interval, 475-948%). With the exception of patients transitioned from NIPPV to IMV, in-hospital outcomes were favorable and improved steadily year by year.

CONCLUSIONS

The use of NIPPV has increased significantly over time among patients hospitalized for acute exacerbations of COPD, whereas the need for intubation and in-hospital mortality has declined. However, the rising mortality rate in a small but expanding group of patients requiring invasive mechanical ventilation after treatment with noninvasive ventilation needs further investigation.

A new perspective on optimal care for patients with COPD

Worldwide, clinicians face the task of providing millions of patients with the best possible treatment and management of COPD. Currently, management primarily involves short-term 'here-and-now' goals, targeting immediate patient benefit. However, although there is considerable knowledge available to assist clinicians in minimising the current impact of COPD on patients, relatively little is known about which dominant factors predict future risks. These predictors may vary for different outcomes, such as exacerbations, mortality, co-morbidities, and the long-term consequences of COPD. We propose a new paradigm to achieve 'optimal COPD care' based on the concept that here-and-now goals should be integrated with goals to improve long-term outcomes and reduce future risks. Whilst knowledge on risk factors for poorer outcomes in COPD is growing and some data exist on positive effects of pharmacological interventions, information on defining the benefits of all commonly used interventions for reducing the risk of various future disease outcomes is still scarce. Greater insight is needed into the relationships between the two pillars of optimal COPD care: 'best current control' and 'future risk reduction'. This broader approach to disease management should result in improved care for every COPD patient now and into the future.

Distribution of Pneumocystis jirovecii in lungs from colonized COPD patients

Pneumocystis jirovecii has been detected in lung tissue from patients with chronic obstructive pulmonary disease (COPD) and is associated with disease severity. The regional distribution of the organism in lungs is unknown, but differences in distribution of Pneumocystis could affect estimates of colonization prevalence. We examined the distribution of Pneumocystis in the lungs of 19 non-HIV-infected patients with COPD who were undergoing lung transplantation. DNA was extracted from explanted lungs. We found Pneumocystis colonization in lung tissue of 42.1% of patients with advanced COPD; however, there was significant regional variation in colonization between lung segments of individual patients. Colonization was detected more commonly in the lower and middle lobes than in the upper lobes. These findings suggest that single samples from an individual may underestimate the prevalence of Pneumocystis colonization and future studies may obtain a higher yield of Pneumocystis colonization detection when sampling the lower lobes.

Elevated N-terminal pro-brain natriuretic peptide is associated with mortality in tobacco smokers independent of airflow obstruction

Background

Tobacco use is associated with an increased prevalence of cardiovascular disease. N-terminal pro-brain natiuretic peptide (NT-proBNP), a widely available biomarker that is associated with cardiovascular outcomes in other conditions, has not been investigated as a predictor of mortality in tobacco smokers. We hypothesized that NT-proBNP would be an independent prognostic marker in a cohort of well-characterized tobacco smokers without known cardiovascular disease.

Methods

Clinical data from 796 subjects enrolled in two prospective tobacco exposed cohorts was assessed to determine factors associated with elevated NT-proBNP and the relationship of these factors and NT-proBNP with mortality.

Results

Subjects were followed for a median of 562 (IQR 252 – 826) days. Characteristics associated with a NT-proBNP above the median (≥49 pg/mL) were increased age, female gender, and decreased body mass index. By time-to-event analysis, an NT-proBNP above the median (≥49 pg/mL) was a significant predictor of mortality (log rank p = 0.02). By proportional hazard analysis controlling for age, gender, cohort, and severity of airflow obstruction, an elevated NT-proBNP level (≥49 pg/mL) remained an independent predictor of mortality (HR = 2.19, 95% CI 1.07–4.46, p = 0.031).

Conclusions

Elevated NT-proBNP is an independent predictor of mortality in tobacco smokers without known cardiovascular disease, conferring a 2.2 fold increased risk of death. Future studies should assess the ability of this biomarker to guide further diagnostic testing and to direct specific cardiovascular risk reduction inventions that may positively impact quality of life and survival.