The purposes of this study were: to describe chest CT findings in normal non-smoking controls and cigarette smokers with and without COPD; to compare the prevalence of CT abnormalities with severity of COPD; and to evaluate concordance between visual and quantitative chest CT (QCT) scoring
Volumetric inspiratory and expiratory CT scans of 294 subjects, including normal non-smokers, smokers without COPD, and smokers with GOLD Stage I-IV COPD, were scored at a multi-reader workshop using a standardized worksheet. There were fifty-eight observers (33 pulmonologists, 25 radiologists); each scan was scored by 9–11 observers. Interobserver agreement was calculated using kappa statistic. Median score of visual observations was compared with QCT measurements.
Interobserver agreement was moderate for the presence or absence of emphysema and for the presence of panlobular emphysema; fair for the presence of centrilobular, paraseptal, and bullous emphysema subtypes and for the presence of bronchial wall thickening; and poor for gas trapping, centrilobular nodularity, mosaic attenuation, and bronchial dilation. Agreement was similar for radiologists and pulmonologists. The prevalence on CT readings of most abnormalities (e.g. emphysema, bronchial wall thickening, mosaic attenuation, expiratory gas trapping) increased significantly with greater COPD severity, while the prevalence of centrilobular nodularity decreased. Concordances between visual scoring and quantitative scoring of emphysema, gas trapping and airway wall thickening were 75%, 87% and 65%, respectively.
Despite substantial inter-observer variation, visual assessment of chest CT scans in cigarette smokers provides information regarding lung disease severity; visual scoring may be complementary to quantitative evaluation.
It can be challenging to maintain longitudinal follow-up of subjects in clinical studies. COPDGene is a multicenter, observational study designed to identify genetic factors associated with COPD and to characterize COPD-related phenotypes. To obtain follow-up data on patient's vital status and outcomes, the COPDGene Longitudinal Follow-up (LFU) Program was developed to supplement its parent study.
We used a telecommunication system that employed automated telephone contact or web-based questions to obtain longitudinal follow-up data in our subjects. A branching questionnaire asked about exacerbations, new therapies, smoking status, development of co-morbid conditions, and general health status. Study coordinators contacted subjects who did not respond to one of the automated methods. We enrolled 10,383 subjects in the COPDGene study. As of August 29, 2011, 7,959 subjects completed 19,955 surveys. On the first survey, 68.8% of subjects who completed their survey did so by electronic means, while 31.3% required coordinator phone follow-up. On each subsequent survey the number of subjects who completed their survey by electronic means increased, while the number of subjects who required coordinator follow-up decreased. Despite many of the patients in the cohort being chronically ill and elderly, there was broad acceptance of the system with over half the cohort using electronic response methods.
The COPDGene LFU Study demonstrated that telecommunications was an effective way to obtain longitudinal follow-up of subjects in a large multicenter study. Web-based and automated phone contacts are accepted by research subjects and could serve as a model for LFU in future studies.
COPD; COPDGene; Emphysema; Longitudinal data collection; Exacerbations; Follow-up studies; Elderly
Using current chemotherapy protocols, over 55% of lymphoma patients fail treatment. Novel agents are needed to improve lymphoma survival. The manganese porphyrin, MnTE-2-PyP5+, augments glucocorticoid-induced apoptosis in WEHI7.2 murine thymic lymphoma cells, suggesting that it may have potential as a lymphoma therapeutic. However, the mechanism by which MnTE-2-PyP5+ potentiates glucocorticoid-induced apoptosis is unknown. Previously, we showed that glucocorticoid treatment increases the steady state levels of hydrogen peroxide ([H2O2]ss) and oxidizes the redox environment in WEHI7.2 cells. In the current study, we found that when MnTE-2-PyP5+ is combined with glucocorticoids, it augments dexamethasone-induced oxidative stress however, it does not augment the [H2O2]ss levels. The combined treatment depletes GSH, oxidizes the 2GSH:GSSG ratio, and causes protein glutathionylation to a greater extent than glucocorticoid treatment alone. Removal of the glucocorticoid-generated H2O2 or depletion of glutathione by BSO prevents MnTE-2-PyP5+ from augmenting glucocorticoid-induced apoptosis. In combination with glucocorticoids, MnTE-2-PyP5+ glutathionylates p65 NF-κB and inhibits NF-κB activity. Inhibition of NF-κB with SN50, an NF-κB inhibitor, enhances glucocorticoid-induced apoptosis to the same extent as MnTE-2-PyP5+. Taken together, these findings indicate that: 1) H2O2 is important for MnTE-2-PyP5+ activity; 2) Mn-TE-2-PyP5+ cycles with GSH; and 3) MnTE-2-PyP5+ potentiates glucocorticoid-induced apoptosis by glutathionylating and inhibiting critical survival proteins, including NF-κB. In the clinic, over-expression of NF-κB is associated with a poor prognosis in lymphoma. MnTE-2-PyP5+ may therefore, synergize with glucocorticoids to inhibit NF-κB and improve current treatment.
MnTE-2-PyP5+; dexamethasone; lymphoma; hydrogen peroxide; glutathione; glutathionylation; NF-κB
Exacerbations of chronic obstructive pulmonary disease (COPD) are associated with accelerated loss of lung function and death. Identification of patients at risk for these events, particularly those requiring hospitalization, is of major importance. Severe pulmonary hypertension is an important complication of advanced COPD and predicts acute exacerbations, though pulmonary vascular abnormalities also occur early in the course of the disease. We hypothesized that a computed tomographic (CT) metric of pulmonary vascular disease (pulmonary artery enlargement, as determined by a ratio of the diameter of the pulmonary artery to the diameter of the aorta [PA:A ratio] of >1) would be associated with severe COPD exacerbations.
We conducted a multicenter, observational trial that enrolled current and former smokers with COPD. We determined the association between a PA:A ratio of more than 1 and a history at enrollment of severe exacerbations requiring hospitalization and then examined the usefulness of the ratio as a predictor of these events in a longitudinal follow-up of this cohort, as well as in an external validation cohort. We used logistic-regression and zero-inflated negative binomial regression analyses and adjusted for known risk factors for exacerbation.
Multivariate logistic-regression analysis showed a significant association between a PA:A ratio of more than 1 and a history of severe exacerbations at the time of enrollment in the trial (odds ratio, 4.78; 95% confidence interval [CI], 3.43 to 6.65; P<0.001). A PA:A ratio of more than 1 was also independently associated with an increased risk of future severe exacerbations in both the trial cohort (odds ratio, 3.44; 95% CI, 2.78 to 4.25; P<0.001) and the external validation cohort (odds ratio, 2.80; 95% CI, 2.11 to 3.71; P<0.001). In both cohorts, among all the variables analyzed, a PA:A ratio of more than 1 had the strongest association with severe exacerbations.
Pulmonary artery enlargement (a PA:A ratio of >1), as detected by CT, was associated with severe exacerbations of COPD. (Funded by the National Heart, Lung, and Blood Institute; ClinicalTrials.gov numbers, NCT00608764 and NCT00292552.)
Rationale: A genome-wide association study (GWAS) for circulating chronic obstructive pulmonary disease (COPD) biomarkers could identify genetic determinants of biomarker levels and COPD susceptibility.
Objectives: To identify genetic variants of circulating protein biomarkers and novel genetic determinants of COPD.
Methods: GWAS was performed for two pneumoproteins, Clara cell secretory protein (CC16) and surfactant protein D (SP-D), and five systemic inflammatory markers (C-reactive protein, fibrinogen, IL-6, IL-8, and tumor necrosis factor-α) in 1,951 subjects with COPD. For genome-wide significant single nucleotide polymorphisms (SNPs) (P < 1 × 10−8), association with COPD susceptibility was tested in 2,939 cases with COPD and 1,380 smoking control subjects. The association of candidate SNPs with mRNA expression in induced sputum was also elucidated.
Measurements and Main Results: Genome-wide significant susceptibility loci affecting biomarker levels were found only for the two pneumoproteins. Two discrete loci affecting CC16, one region near the CC16 coding gene (SCGB1A1) on chromosome 11 and another locus approximately 25 Mb away from SCGB1A1, were identified, whereas multiple SNPs on chromosomes 6 and 16, in addition to SNPs near SFTPD, had genome-wide significant associations with SP-D levels. Several SNPs affecting circulating CC16 levels were significantly associated with sputum mRNA expression of SCGB1A1 (P = 0.009–0.03). Several SNPs highly associated with CC16 or SP-D levels were nominally associated with COPD in a collaborative GWAS (P = 0.001–0.049), although these COPD associations were not replicated in two additional cohorts.
Conclusions: Distant genetic loci and biomarker-coding genes affect circulating levels of COPD-related pneumoproteins. A subset of these protein quantitative trait loci may influence their gene expression in the lung and/or COPD susceptibility.
Clinical trial registered with www.clinicaltrials.gov (NCT 00292552).
biomarker; chronic obstructive pulmonary disease; genome-wide association study
Two recent metaanalyses of genome-wide association studies conducted by the CHARGE and SpiroMeta consortia identified novel loci yielding evidence of association at or near genome-wide significance (GWS) with FEV1 and FEV1/FVC. We hypothesized that a subset of these markers would also be associated with chronic obstructive pulmonary disease (COPD) susceptibility. Thirty-two single-nucleotide polymorphisms (SNPs) in or near 17 genes in 11 previously identified GWS spirometric genomic regions were tested for association with COPD status in four COPD case-control study samples (NETT/NAS, the Norway case-control study, ECLIPSE, and the first 1,000 subjects in COPDGene; total sample size, 3,456 cases and 1,906 controls). In addition to testing the 32 spirometric GWS SNPs, we tested a dense panel of imputed HapMap2 SNP markers from the 17 genes located near the 32 GWS SNPs and in a set of 21 well studied COPD candidate genes. Of the previously identified GWS spirometric genomic regions, three loci harbored SNPs associated with COPD susceptibility at a 5% false discovery rate: the 4q24 locus including FLJ20184/INTS12/GSTCD/NPNT, the 6p21 locus including AGER and PPT2, and the 5q33 locus including ADAM19. In conclusion, markers previously associated at or near GWS with spirometric measures were tested for association with COPD status in data from four COPD case-control studies, and three loci showed evidence of association with COPD susceptibility at a 5% false discovery rate.
Lung disease due to Mycobacterium avium complex (MAC) organisms is increasing. A greater understanding of the host immune response to MAC organisms will provide a foundation to develop novel therapies for these recalcitrant infections. IL-32 is a newly described pro-inflammatory cytokine that enhances host immunity against various microbial pathogens. Cytokines that induce IL-32 such as interferon-gamma, IL-18, IL-12 and tumor necrosis factor-alpha are of considerable importance to mycobacterial immunity. We performed immunohistochemistry and morphometric analysis to quantify IL-32 expression in the lungs of 11 patients with MAC lung disease and 10 controls with normal lung tissues. After normalizing for basement membrane length, there was a profound increase in IL-32 expression in the airway epithelial cells of the MAC-infected lungs compared with controls. Following normalization for alveolar surface area, there was a trend toward increased IL-32 expression in type II alveolar cells and alveolar macrophages in the lungs of MAC patients. Human airway epithelial cells (BEAS-2B) infected with M. avium produced IL-32 by a nuclear factor-kappa B-dependent mechanism. In both BEAS-2B cells and human monocyte-derived macrophages, exogenous IL-32γ significantly reduced the growth of intracellular M. avium. This finding was corroborated by an increase in the number of intracellular M. avium recovered from THP-1 monocytes silenced for endogenous IL-32 expression. The anti-mycobacterial effect of IL-32 may be due, in part, to increased apoptosis of infected cells. These findings indicate that IL-32 facilitates host defense against MAC organisms but may also contribute to the airway inflammation associated with MAC pulmonary disease.
cytokine; immunohistochemistry; non-tuberculous mycobacteria
Recent studies in animal models of bronchopulmonary dysplasia (BPD) suggest that antioxidant treatments may be beneficial for the disease. However, the mechanisms by which these drugs improve the course of BPD are not completely known. Alpha1-antitrypsin (α1-AT) is one of the major serine protease inhibitors in human plasma that has anti-elastase and anti-apoptotic activities. Both activities of α1-AT are dependent on its reactive site loop (RSL), which is highly susceptible to oxidative inactivation. In this study, we investigated the elastase inhibitory activity of α1-AT in two different baboon models of BPD, the “new BPD” and the “severe BPD” models, and determined the effect of treatment with a catalytic antioxidant, Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP), on the elastase inhibitory activity of α1-AT in the severe BPD model. Our results demonstrate the presence of sufficient elastase inhibitory activity of the airway α1-AT in the new, but not the severe BPD model. Treatment of severe BPD group baboons with the catalytic antioxidant MnTE-2-PyP resulted in augmentation of the elastase inhibitory activity of α1-AT. These findings suggest that prevention of the oxidative inactivation of α1-AT may be one of the mechanisms by which antioxidant therapy improves the pulmonary outcomes in animal models of severe BPD.
Cigarette smoking is a major risk factor for COPD and COPD severity. Previous genome-wide association studies (GWAS) have identified numerous single nucleotide polymorphisms (SNPs) associated with the number of cigarettes smoked per day (CPD) and a Dopamine Beta-Hydroxylase (DBH) locus associated with smoking cessation in multiple populations.
To identify SNPs associated with lifetime average and current CPD, age at smoking initiation, and smoking cessation in COPD subjects.
GWAS were conducted in 4 independent cohorts encompassing 3,441 ever-smoking COPD subjects (GOLD stage II or higher). Untyped SNPs were imputed using HapMap (phase II) panel. Results from all cohorts were meta-analyzed.
Several SNPs near the HLA region on chromosome 6p21 and in an intergenic region on chromosome 2q21 showed associations with age at smoking initiation, both with the lowest p=2×10−7. No SNPs were associated with lifetime average CPD, current CPD or smoking cessation with p<10−6. Nominally significant associations with candidate SNPs within alpha-nicotinic acetylcholine receptors 3/5 (CHRNA3/CHRNA5; e.g. p=0.00011 for SNP rs1051730) and Cytochrome P450 2A6 (CYP2A6; e.g. p=2.78×10−5 for a nonsynonymous SNP rs1801272) regions were observed for lifetime average CPD, however only CYP2A6 showed evidence of significant association with current CPD. A candidate SNP (rs3025343) in the DBH was significantly (p=0.015) associated with smoking cessation.
We identified two candidate regions associated with age at smoking initiation in COPD subjects. Associations of CHRNA3/CHRNA5 and CYP2A6 loci with CPD and DBH with smoking cessation are also likely of importance in the smoking behaviors of COPD patients.
Chronic Obstructive Pulmonary Disease (COPD); Genome Wide Association study (GWAS); smoking behaviors; Single Nucleotide Polymorphism (SNP)
Rationale: The characterization of young adults who develop late-onset diseases may augment the detection of novel genes and promote new pathogenic insights.
Methods: We analyzed data from 2,500 individuals of African and European ancestry in the COPDGene Study. Subjects with severe, early-onset chronic obstructive pulmonary disease (COPD) (n = 70, age < 55 yr, FEV1 < 50% predicted) were compared with older subjects with COPD (n = 306, age > 64 yr, FEV1 < 50% predicted).
Measurements and Main Results: Subjects with severe, early-onset COPD were predominantly females (66%), P = 0.0004. Proportionally, early-onset COPD was seen in 42% (25 of 59) of African Americans versus 14% (45 of 317) of non-Hispanic whites, P < 0.0001. Other risk factors included current smoking (56 vs. 17%, P < 0.0001) and self-report of asthma (39 vs. 25%, P = 0.008). Maternal smoking (70 vs. 44%, P = 0.0001) and maternal COPD (23 vs. 12%, P = 0.03) were reported more commonly in subjects with early-onset COPD. Multivariable regression analysis found association with African American race, odds ratio (OR), 7.5 (95% confidence interval [CI], 2.3–24; P = 0.0007); maternal COPD, OR, 4.7 (95% CI, 1.3–17; P = 0.02); female sex, OR, 3.1 (95% CI, 1.1–8.7; P = 0.03); and each pack-year of smoking, OR, 0.98 (95% CI, 0.96–1.0; P = 0.03).
Conclusions: These observations support the hypothesis that severe, early-onset COPD is prevalent in females and is influenced by maternal factors. Future genetic studies should evaluate (1) gene-by-sex interactions to address sex-specific genetic contributions and (2) gene-by-race interactions.
chronic obstructive pulmonary disease; female; African Americans
Severe hypoxemia is a major complication of chronic obstructive pulmonary disease (COPD). Long term oxygen therapy is beneficial in hypoxemic COPD patients. However, the clinical and radiographic predictors of hypoxemia and the use of oxygen therapy are not well described. This study aimed to find the correlates of resting hypoxemia and the pattern of oxygen use in moderate to severe COPD patients.
Subjects with GOLD stage II or higher COPD from the first 2500 COPDGene subjects were included in this analysis. All subjects were current or ex-smokers between ages 45 and 80. Severe resting hypoxemia was defined as room air oxygen saturation (SpO2) ≤ 88%. Use of supplemental oxygen therapy was determined by questionnaire.
Eighty-two of 1060 COPD subjects (7.7%) had severe resting hypoxemia. Twenty-one of the 82 (25.6%) were not using continuous supplemental oxygen. Female sex, higher BMI, lower FEV1, and enrollment in Denver were independent risk factors for hypoxemia; emphysema severity on quantitative chest CT scan did not predict hypoxemia. 132 of 971(13.6%) subjects without severe resting hypoxemia were using continuous supplemental oxygen. In non-hypoxemic oxygen users, Denver recruitment, higher BMI, lower FEV1, and more severe dyspnea were associated with the use of continuous oxygen.
A large number of COPD patients without severe hypoxemia were using supplemental oxygen therapy and the pattern of oxygen use was affected by factors other than resting SpO2 and emphysema severity. Longitudinal data will be required to reveal the effects of oxygen therapy in this subgroup.
Hypoxemia; long-term oxygen therapy; COPD; emphysema
Rationale: A significant proportion of smokers have lung function impairment characterized by a reduced FEV1 with a preserved FEV1/FVC ratio. These smokers are a poorly characterized group due to their systematic exclusion from chronic obstructive pulmonary disease (COPD) studies.
Objectives: To characterize the clinical, functional, and radiographic features of Global Initiative for Chronic Obstructive Lung Disease (GOLD)-Unclassified (FEV1/FVC ≥ 0.7 and FEV1 < 80% predicted) and lower limits of normal (LLN)-unclassified (FEV1/FVC ≥ LLN and FEV1 < LLN) subjects compared to smokers with normal lung function and subjects with COPD.
Methods: Data from the first 2,500 subjects enrolled in the COPDGene study were analyzed. All subjects had 10 or more pack-years of smoking and were between the ages of 45 and 80 years. Multivariate regression models were constructed to determine the clinical and radiological variables associated with GOLD-Unclassified (GOLD-U) and LLN-Unclassified status. Separate multivariate regressions were performed in the subgroups of subjects with complete radiologic measurement variables available.
Measurements and Main Results: GOLD-U smokers account for 9% of smokers in COPDGene and have increased body mass index (BMI), a disproportionately reduced total lung capacity, and a higher proportion of nonwhite subjects and subjects with diabetes. GOLD-U subjects exhibit increased airway wall thickness compared to smoking control subjects and decreased gas trapping and bronchodilator responsiveness compared to subjects with COPD. When LLN criteria were used to define the “unclassified” group, African American subjects were no longer overrepresented. Both GOLD-U and LLN-Unclassified subjects demonstrated a wide range of lung function impairment, BMI, and percentage of total lung emphysema.
Conclusions: Subjects with reduced FEV1 and a preserved FEV1/FVC ratio are a heterogeneous group with significant symptoms and functional limitation who likely have a variety of underlying etiologies beyond increased BMI.
Clinical trial registered with www.clinicaltrials.gov (NCT000608764).
lung diseases, classification; lung diseases, diagnosis; lung diseases, epidemiology
We performed a genome-wide association study in non-Hispanic white subjects with fibrotic idiopathic interstitial pneumonias (N=1616) and controls (N=4683); replication was assessed in 876 cases and 1890 controls. We confirmed association with TERT and MUC5B on chromosomes 5p15 and 11p15, respectively, the chromosome 3q26 region near TERC, and identified 7 novel loci (PMeta = 2.4×10−8 to PMeta = 1.1×10−19). The novel loci include FAM13A (4q22), DSP (6p24), OBFC1 (10q24), ATP11A (13q34), DPP9 (19p13), and chromosomal regions 7q22 and 15q14-15. Our results demonstrate that genes involved in host defense, cell-cell adhesion, and DNA repair contribute to the risk of fibrotic IIP.
Mycobacterium abscessus (M. abscessus) infections, particularly those causing chronic lung diseases, are becoming more prevalent worldwide. M. abscessus infections are difficult to treat due to antibiotic resistance. Thus, new treatment options are urgently needed. M. abscessus are intracellular pathogens that primarily infect macrophages and fibroblasts. Because this bacterium has only recently been identified as a separate species, very little is known about M. abscessus-host interactions and how M. abscessus growth is regulated. Oxidative stress has long been shown to inhibit growth of bacterial organisms. However, some intracellular bacteria, such as Mycobacterium tuberculosis, grow well in oxidizing environments. In the present study, we show that M. abscessus infection causes the host cell environment to become more oxidizing. Furthermore, we show that a more oxidizing environment leads to enhanced growth of M. abscessus inside macrophages. In the presence of the antioxidants, MnTE-2-PyP (chemical name: Manganese (II) Meso-Tetrakis-(N-Methylpyridinium-2-yl) porphryin) or N-acetyl-L-cysteine (NAC), M. abscessus growth is inhibited. These results lead us to postulate that antioxidants may aid in the treatment for M. abscessus infections.
Mycobacterium abscessus; oxidation; antioxidants; MnTE-2-PyP; N-acetyl-L-cysteine; THP-1; alveolar macrophages; smoking
The coexistence of COPD and asthma is widely recognized but has not been well described. This study characterizes clinical features, spirometry, and chest CT scans of smoking subjects with both COPD and asthma.
We performed a cross-sectional study comparing subjects with COPD and asthma to subjects with COPD alone in the COPDGene Study.
119 (13%) of 915 subjects with COPD reported a history of physician-diagnosed asthma. These subjects were younger (61.3 vs 64.7 years old, p = 0.0001) with lower lifetime smoking intensity (43.7 vs 55.1 pack years, p = 0.0001). More African-Americans reported a history of asthma (33.6% vs 15.6%, p < 0.0001). Subjects with COPD and asthma demonstrated worse disease-related quality of life, were more likely to have had a severe COPD exacerbation in the past year, and were more likely to experience frequent exacerbations (OR 3.55 [2.19, 5.75], p < 0.0001). Subjects with COPD and asthma demonstrated greater gas-trapping on chest CT. There were no differences in spirometry or CT measurements of emphysema or airway wall thickness.
Subjects with COPD and asthma represent a relevant clinical population, with worse health-related quality of life. They experience more frequent and severe respiratory exacerbations despite younger age and reduced lifetime smoking history.
Airway hyperresponsiveness; asthma; Chronic obstructive pulmonary disease; emphysema; Exacerbation; Gas-trapping
Epidemiological studies indicate that tobacco smoke exposure accounts for nearly 90% of cases of chronic obstructive pulmonary disease (COPD) and lung cancer. However, genetic factors may explain why 10%–30% of smokers develop these complications. This perspective reviews the evidence suggesting that COPD is closely linked to susceptibility to lung cancer and outlines the potential relevance of this observation. Epidemiological studies show that COPD is the single most important risk factor for lung cancer among smokers and predates lung cancer in up to 80% of cases. Genome-wide association studies of lung cancer, lung function, and COPD have identified a number of overlapping “susceptibility” loci. With stringent phenotyping, it has recently been shown that several of these overlapping loci are independently associated with both COPD and lung cancer. These loci implicate genes underlying pulmonary inflammation and apoptotic processes mediated by the bronchial epithelium, and link COPD with lung cancer at a molecular genetic level. It is currently possible to derive risk models for lung cancer that incorporate lung cancer-specific genetic variants, recently identified “COPD-related” genetic variants, and clinical variables. Early studies suggest that single nucleotide polymorphism-based risk stratification of smokers might help better target novel prevention and early diagnostic strategies in lung cancer.
lung cancer; chronic obstructive pulmonary disease; association study; single nucleotide polymorphism; risk model
Because of reduced antioxidant defenses, β-cells are especially vulnerable to free radical and inflammatory damage. Commonly used antirejection drugs are excellent at inhibiting the adaptive immune response; however, most are harmful to islets and do not protect well from reactive oxygen species and inflammation resulting from islet isolation and ischemia-reperfusion injury. The aim of this study was to determine whether redox modulation, using the catalytic antioxidant (CA), FBC-007, can improve in vivo islet function post-transplant.
RESEARCH DESIGN AND METHODS
The abilities of redox modulation to preserve islet function were analyzed using three models of ischemia-reperfusion injury: 1) streptozotocin (STZ) treatment of human islets, 2) STZ-induced murine model of diabetes, and 3) models of syngeneic, allogeneic, and xenogeneic transplantation.
Incubating human islets with catalytic antioxidant during STZ treatment protects from STZ-induced islet damage, and systemic delivery of catalytic antioxidant ablates STZ-induced diabetes in mice. Islets treated with catalytic antioxidant before syngeneic, suboptimal syngeneic, or xenogeneic transplant exhibited superior function compared with untreated controls. Diabetic murine recipients of catalytic antioxidant–treated allogeneic islets exhibited improved glycemic control post-transplant and demonstrated a delay in allograft rejection. Treating recipients systemically with catalytic antioxidant further extended the delay in allograft rejection.
Pretreating donor islets with catalytic antioxidant protects from antigen-independent ischemia-reperfusion injury in multiple transplant settings. Treating systemically with catalytic antioxidant protects islets from antigen-independent ischemia-reperfusion injury and hinders the antigen-dependent alloimmune response. These results suggest that the addition of a redox modulation strategy would be a beneficial clinical approach for islet preservation in syngeneic, allogeneic, and xenogeneic transplantation.
COPDGeneis a multicenter observational study designed to identify genetic factors associated with COPD. It will also characterize chest CT phenotypes in COPD subjects, including assessment of emphysema, gas trapping, and airway wall thickening. Finally, subtypes of COPD based on these phenotypes will be used in a comprehensive genome-wide study to identify COPD susceptibility genes.
COPDGene will enroll 10,000 smokers with and without COPD across the GOLD stages. Both Non-Hispanic white and African-American subjects are included in the cohort. Inspiratory and expiratory chest CT scans will be obtained on all participants. In addition to the cross-sectional enrollment process, these subjects will be followed regularly for longitudinal studies. A genome-wide association study (GWAS) will be done on an initial group of 4000 subjects to identify genetic variants associated with case-control status and several quantitative phenotypes related to COPD. The initial findings will be verified in an additional 2000 COPD cases and 2000 smoking control subjects, and further validation association studies will be carried out.
COPDGene will provide important new information about genetic factors in COPD, and will characterize the disease process using high resolution CT scans. Understanding genetic factors and CT phenotypes that define COPD will potentially permit earlier diagnosis of this disease and may lead to the development of treatments to modify progression.
Sustained oxidative stress is a known sequel to focal cerebral ischemia. This study examined the effects of treatment with a single dose or sustained infusion of the redox-modulating MnPorphyrin MnIIITDE-2-ImP5+ on outcome from middle cerebral artery occlusion (MCAO) in the rat. Normothermic rats were subjected to 90 min MCAO followed by 90 min reperfusion and then were treated with a single intracerebroventricular dose of MnIIITDE-2-ImP5+. Neurologic and histologic outcomes were assessed at 1 or 8 weeks post-ischemia. A single dose of MnIIITDE-2-ImP5+ caused a dose-dependent improvement in histologic and neurologic outcome when assessed 1 week post-ischemia. MnIIITDE-2-ImP5+ afforded preservation of brain aconitase activity at 5.5 hrs after reperfusion onset, consistent with its known antioxidant properties. MnIIITDE-2-ImP5+ also attenuated post-ischemic NF-κ B activation. Evidence for effects on cerebral infarct size and neurologic function had completely dissipated when rats were allowed to survive for 8 weeks post-ischemia. In contrast, a 1-week continuous intracerebroventricular MnIIITDE-2-ImP5+ infusion caused persistent and substantive reduction in both cerebral infarct size and neurologic deficit at 8 weeks post-ischemia. Pharmacologic modulation of post-ischemic oxidative stress is likely to require sustained intervention for enduring efficacy in improving neurologic and histologic outcome from a transient focal ischemic insult.
Oxidative damage is a major cause of lung injury during systemic inflammatory response syndrome. In the present study, expression of an anti-oxidant enzyme, extracellular superoxide dismutase (EC-SOD), and its protective role against pulmonary oxidative damage were investigated using mouse models of systemic inflammation. Intraperitoneal injection with bacterial endotoxin lipopolysaccharides (LPS, 20 mg/kg) caused oxidative damage in lungs as assessed by increased tyrosine nitration in proteins. LPS administration also resulted in a rapid and significant loss of pulmonary EC-SOD more than 80% in a time- and dose-dependent manner, but other types of SODs, cytoplasmic CuZn-SOD and mitochondrial Mn-SOD, were not affected. EC-SOD protein is most abundant in lungs but also present at high levels in other tissues such as heart and white fat; however, the LPS-mediated decrease in this enzyme was most apparent in the lungs. Intravenous injection of mice with tumor necrosis factor α (10 μg per mouse) also caused 60% decrease in EC-SOD in lungs, suggesting that the EC-SOD down-regulation is mediated by this LPS-inducible inflammatory cytokine. A protective role of EC-SOD against LPS-mediated systemic inflammation was shown by an increased survival rate (75% vs.29% in 5 days) and decreased pulmonary oxidative damage in EC-SOD transgenic mice that overexpress the human EC-SOD gene. These results demonstrate that the inflammation-mediated EC-SOD down-regulation has a major pathophysiological impact during the systemic inflammatory response syndrome.
EC-SOD; oxidative stress; nitro tyrosine; systemic inflammation; superoxide dismutase; endotoxemia
Substantial evidence suggests that there is genetic susceptibility to chronic obstructive pulmonary disease (COPD). To identify common genetic risk variants, we performed a genome-wide association study in 2940 cases and 1380 smoking controls with normal lung function. We demonstrate a novel susceptibility locus at 4q22.1 in FAM13A (rs7671167, OR=0.76, P=8.6×10−8) and provide evidence of replication in one case-control and two family-based cohorts (for all studies, combined P=1.2×10−11).
Mycobacterium abscessus is a rapidly growing environmental mycobacterium that can cause severe skin, soft tissue, and lung infections. M. abscessus grows inside macrophages, and these cells release a vast number of proinflammatory cytokines in response to infections. The metalloporphyrin, MnTE-2-PyP, is a broad antioxidant that reduces inflammatory cell signaling. Macrophage-like THP-1 cells were infected with M. abscessus in the presence or absence of MnTE-2-PyP. MnTE-2-PyP significantly decreased, in a dose-dependent manner, the number of M. abscessus organisms recovered from infected THP-1 cells 4 and 8 days after infection. Furthermore, when combined with clarithromycin, MnTE-2-PyP additively reduced the number of cells associated with M. abscessus. A mechanism of bacterial growth inhibition by MnTE-2-PyP was then elucidated. It was found that MnTE-2-PyP promoted the survival of infected THP-1 cells and increased fusion of M. abscessus–containing phagosomes with lysosomes.
antioxidant mimetic; MnTE-2-PyP; Mycobacterium abscessus; THP-1 cells
Glucocorticoid-induced apoptosis is exploited for the treatment of hematologic malignancies. Innate and acquired resistance limits treatment efficacy; however, resistance mechanisms are not well understood. Previously, using WEHI7.2 murine thymic lymphoma cells, we found that increasing the resistance to hydrogen peroxide by catalase transfection or selection for hydrogen peroxide resistance caused glucocorticoid resistance. This suggests the possibility that increasing hydrogen peroxide sensitivity could sensitize the cells to glucocorticoids. In other cell types, increasing manganese superoxide dismutase (MnSOD) can increase intracellular hydrogen peroxide. The current study demonstrated that increased expression of MnSOD sensitized WEHI7.2 cells to glucocorticoid-induced apoptosis and hydrogen peroxide. Treatment of WEHI7.2 cells with the catalytic antioxidant Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP5+), a manganoporphyrin, mimicked the effects of increased MnSOD expression. MnTE-2-PyP5+ also sensitized WEHI7.2 cells to cyclophosphamide and inhibited cell growth; it had no effect on the WEHI7.2 cell response to doxorubicin or vincristine. In primary follicular lymphoma cells, MnTE-2-PyP5+ increased cell death due to dexamethasone. Treatment of H9c2 cardiomyocytes with MnTE-2-PyP5+ inhibited doxorubicin cytotoxicity. The profile of MnTE-2-PyP5+ effects suggests MnTE-2-PyP5+ has potential for use in hematologic malignancies that are treated with glucocorticoids, cyclophosphamide and doxorubicin.
SOD2; AEOL 10113
Rationale: Nitric oxide (NO) plays an important role in lung development and perinatal lung function, and pulmonary NO synthases (NOS) are decreased in bronchopulmonary dysplasia (BPD) following preterm birth. Fetal estradiol levels increase during late gestation and estradiol up-regulates NOS, suggesting that after preterm birth estradiol deprivation causes attenuated lung NOS resulting in impaired pulmonary function.
Objective: To test the effects of postnatal estradiol administration in a primate model of BPD over 14 days after delivery at 125 days of gestation (term = 185 d).
Methods: Cardiopulmonary function was assessed by echocardiography and whole body plethysmography. Lung morphometric and histopathologic analyses were performed, and NOS enzymatic activity and abundance were measured.
Measurements and Main Results: Estradiol caused an increase in blood pressure and ductus arteriosus closure. Expiratory resistance and lung compliance were also improved, and this occurred before spontaneous ductal closure. Furthermore, both oxygenation and ventilation indices were improved with estradiol, and the changes in lung function and ventilatory support requirements persisted throughout the study period. Whereas estradiol had negligible effect on indicators of lung inflammation and on lung structure assessed after the initial 14 days of ventilatory support, it caused an increase in lung neuronal and endothelial NOS enzymatic activity.
Conclusions: In a primate model of BPD, postnatal estradiol treatment had favorable cardiovascular impact, enhanced pulmonary function, and lowered requirements for ventilatory support in association with an up-regulation of lung NOS. Estradiol may be an efficacious postnatal therapy to improve lung function and outcome in preterm infants.
Rationale: Extracellular superoxide dismutase (EC-SOD) is a potent antioxidant that plays an important role in controlling oxidant-mediated stress and inflammation. High levels of EC-SOD are found in the lung. Acute lung injury (ALI) frequently occurs in patients with infection, and levels of EC-SOD have been shown to modulate severity of lung injury in transgenic animal models of endotoxemia-induced ALI. An R213G single nucleotide polymorphism (SNP) has been shown to alter levels of EC-SOD and patient outcomes in chronic obstructive pulmonary disease (COPD) and ischemic heart disease.
Objectives: To determine genetic variation in the promoter and EC-SOD gene and to examine whether EC-SOD haplotype blocks are associated with clinical outcomes.
Methods: We sequenced the EC-SOD promoter and gene to determine genetic variation and linkage disequilibrium (LD) patterns in a European American population. Two separate patient populations with infection-associated ALI were also evaluated to determine whether EC-SOD haplotypes were associated with clinical outcomes.
Measurements and Main Results: Sequencing resulted in the identification of 28 SNPs with relatively strong LD and 1 block consisting of 4691-5321-5360-5955-5982. This specific block was shown to be protective in two separate patient populations with infection associated ALI. In particular, patients with a GCCT haplotype had a reduced risk of time on the ventilator and mortality.
Conclusions: These results indicate that a GCCT haplotype may reduce inflammation in the lung, thereby decreasing the severity of lung injury and ultimately protecting patients from mortality associated with infection-induced ALI.
EC-SOD; haplotypes; acute lung injury; single nucleotide polymorphism