Update in Chronic Obstructive Pulmonary Disease 2009

Immune system benefits of pulmonary rehabilitation in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a respiratory disease characterized by pulmonary and systemic inflammation. Inflammatory mediators show relationships with shortness of breath, exercise intolerance and health related quality of life. Pulmonary rehabilitation (PR), a comprehensive education and exercise training programme, is the most effective therapy for COPD and is associated with reduced exacerbation and hospitalization rates and increased survival. Exercise training, the primary physiological intervention within PR, is known to exert a beneficial anti-inflammatory effect in health and chronic diseases. The question of this review article is whether exercise training can also make such a beneficial anti-inflammatory effect in COPD. Experimental studies using smoke exposure mice models suggest that the response of the immune system to exercise training is favourably anti-inflammatory. However, the evidence about the response of most known inflammatory mediators (C-reactive protein, tumour necrosis factor α, interleukin 6, interleukin 10) to exercise training in COPD patients is inconsistent, making it difficult to conclude whether regular exercise training has an anti-inflammatory effect in COPD. It is also unclear whether COPD patients with more persistent inflammation are a subgroup that would benefit more from hypothesized immunomodulatory effects of exercise training (i.e., personalized treatment). Nevertheless, it seems that PR combined with maintenance exercise training (i.e., lifestyle change) might be more beneficial in controlling inflammation and slowing disease progress in COPD patients, specifically in those with early stages of disease.

Does Chronic Obstructive Pulmonary Disease Originate from Different Cell Types?

The onset of chronic obstructive pulmonary disease (COPD) is heterogeneous, and current approaches to define distinct disease phenotypes are lacking. In addition to clinical methodologies, subtyping COPD has also been challenged by the reliance on human lung samples from late-stage diseases. Different COPD phenotypes may be initiated from the susceptibility of different cell types to cigarette smoke, environmental pollution, and infections at early stages that ultimately converge at later stages in airway remodeling and destruction of the alveoli when the disease is diagnosed. This perspective provides discussion points on how studies to date define different cell types of the lung that can initiate COPD pathogenesis, focusing on the susceptibility of macrophages, T and B cells, mast cells, dendritic cells, endothelial cells, and airway epithelial cells. Additional cell types, including fibroblasts, smooth muscle cells, neuronal cells, and other rare cell types not covered here, may also play a role in orchestrating COPD. Here, we discuss current knowledge gaps, such as which cell types drive distinct disease phenotypes and/or stages of the disease and which cells are primarily affected by the genetic variants identified by whole genome-wide association studies. Applying new technologies that interrogate the functional role of a specific cell type or a combination of cell types as well as single-cell transcriptomics and proteomic approaches are creating new opportunities to understand and clarify the pathophysiology and thereby the clinical heterogeneity of COPD.

Relationship between Vitamin D Level and Serum TNF-α Concentration on the Severity of Chronic Obstructive Pulmonary Disease

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) is a chronic inflammatory disease and disturbed bacterial clearance. Vitamin D deficiency is sometimes observed in COPD patients and as significant roles in increasing inflammation of airway obstruction and systemic obstruction, increasing pro-inflammatory cytokine including TNF-α, reduction of bacterial clearance and increase exacerbation risk due to infection. Also, vitamin D plays significant roles in the metabolism of calcium and mineralisation of bones and regulation system of immune. TNF-α also has essential roles in pathogenesis and inflammation of COPD. Several studies that investigate the relationship between vitamin D level and serum TNF-α concentration in COPD patients are relatively uncommon, including in Indonesia.

AIM

This study aimed to assess the relationship between vitamin D level and TNF-α concentration in patients on the severity of the chronic obstructive pulmonary disease.

METHODS

This study was a hospital-based descriptive cross-sectional study. Total samples were 50 COPD patients with the average age of older than 60 years during their enrollments at the Department of Pulmonology and Respiratory Medicine of the Dr Wahidin Sudirohusodo General Hospital Makassar in September 2018-January 2019. All procedures of the present study were reviewed and approved by the Research Ethics Committee of Medicine Faculty of Hasanuddin University. The severity of COPD was assessed according to the combination of COPD assessment stages that referred to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) Guideline 2015 that consisted of the combination of scoring COPD Assessment Test (CAT), the modified Medical Research Council (mMRC) questionnaire and results of the spirometry measurement. Assessment of airway obstruction levels referred to the GOLD spirometry criteria. Determination of thoracic photographs was conducted to verify the COPD diagnosis of the severity of COPD. Determination of serum TNF-α concentration and vitamin D3 [1,25(OH)2D3] level used the ELISA method.

RESULTS

The majority of COPD patients were observed in the category of older than 60 years old accounted for 34 COPD patients (68%), and the majority of COPD patients were males accounted for 47 males with COPD (94%). The majority of COPD patients were observed in the group of D (38%). All the study subjects observed in this study were smokers, and 82% of them were in the category of heavy smokers. 21 study subjects had higher concentration of serum TNF-α (tertile 3 = 0.21-1.83 pg/dl), 20 study subjects and lower level of vitamin D (tertile 1 = 182.1-364.5 pg/dl). The majority of the study subjects (38%) were in the category of severe COPD (category D of the severity of COPD at the tertile 3) according to the GOLD Combine Assessment. Given the relationship between vitamin D level and serum TNF-α concentration on the airway obstruction, there were significant positive correlations between the increase of vitamin D levels and the increase of serum TNF-α concentrations on airway obstruction. Given the relationship between vitamin D level and serum TNF-α concentration on the severity of COPD, there were significant positive correlations between the increase of vitamin D levels (tertiles 1, 2 and 3) and the increase of serum TNF-α concentrations on the severity of COPD at p-value < 0.05. Overall, there were non-linear relationships between vitamin D level and serum TNF-α concentration on the severity of COPD.

CONCLUSIONS

Serum TNF-α concentration was positively associated with airway obstruction level and severity of COPD. Low level of vitamin D was negatively associated with airway obstruction level and severity of COPD. Vitamin D3 level (1,25(OH)2D) was negatively associated with serum TNF-α concentration and airway obstruction level and severity of COPD.

TERT gene polymorphisms are associated with chronic obstructive pulmonary disease risk in the Chinese Li population

Background

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality worldwide and is characterized by a partially reversible airflow limitation. Currently, many studies put forward that COPD is associated with both genetic and environmental factors. It has been reported that germline mutations in telomerase are risk factors for COPD susceptibility. In this study, we validated the association between TERT polymorphisms and COPD risk with a case–control study in the Chinese Li population.

Methods

A total of 279 COPD patients and 290 control individuals were recruited. We identified five single nucleotide polymorphisms (SNPs) in TERT that were associated with COPD. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated in logistic regression models after adjusting for age and gender to assess the association.

Results

In the genetic model analysis, we found the “C/T‐T/T” genotype of rs10069690 in TERT was associated with an increased COPD risk in the dominant model (p = 0.046); the rs2853677 in TERT was significantly associated with increased COPD risk based on the codominant model (“A/G” genotype, p = 0.033), dominant model (A/G‐G/G genotype, p = 0.0091), and log‐additive model (p = 0.023). The rs2853676 in TERT could increase the risk of COPD in the dominant model (“C/T‐T/T” genotype, p = 0.026) and in the Log‐additive model (p = 0.022).

Conclusion

Our data shed new light on the association between TERT SNPs and COPD susceptibility in the Chinese Li population.

Relation between Vitamin D Deficiency and Severity of Chronic Obstructive Pulmonary Disease-A Case Control Study

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disorder characterized by irreversible and progressive limitation of expiratory airflow. COPD is now considered as a systemic disease with several extra-pulmonary manifestations which include osteoporosis, muscle weakness, arrhythmia, stroke, cancer etc. The role of vitamin D in skeletal integrity is well established. Role of it in several other diseases like autoimmune, infectious, respiratory and cardiovascular diseases has been increasingly recognised. Data on vitamin D status in COPD in Indian population was limited while those comparing vitamin D with stage, pack year and body mass index were lacking.

AIM

To assess Vitamin D in subjects with COPD and matched controls and also to study the variability in serum vitamin D levels with COPD disease characteristics.

MATERIALS AND METHODS

A total of 162 patients aged 18-65 years from south India presenting to kasturba hospital were included in the study. Serum 25- hydroxy-vitamin D were measured in 81 COPD patients (combined COPD stage A-D) and compared with 81 age and gender matched controls. Level < 20 ng/ml defined deficiency. Risk estimate with Odds ratio and association of COPD characteristics with Vitamin D was assessed using logistic regression analysis.

RESULTS

COPD patients had an increased risk for vitamin D deficiency compared to controls after adjustment for age and gender(OR =2.687 (1.40,5.13)). Variables associated with lower 25(OH) D levels in COPD patients were higher pack year (p=0.001), current smoking status (p=0.026), Low BMI (p=0.02), and GOLD stage III- IV (p=0.001).

CONCLUSION

COPD was associated with an increased risk of vitamin D deficiency, and there was a significant association between vitamin D levels and Combined COPD stage severity. Also, a higher pack year and a low BMI are associated with lower levels of vitamin D.

Impact of chronic inflammatory airway disease on stroke severity and long-term survival after ischemic stroke--a retrospective analysis

Background

Chronic inflammatory airway disease (CIAD) has emerged as independent risk factor for cardiovascular mortality and ischemic stroke but the impact of co-existing CIAD in patients with ischemic stroke is less clear.

Methods

We retrospectively analyzed 1013 patients with acute ischemic stroke who were consecutively admitted to the Department of Neurology, Charité - Universitätsmedizin Berlin, Germany within one year. Mean follow-up was 80 months (IQR 32–85 months). Using multivariable regression models we analyzed the impact of CIAD (defined as chronic obstructive pulmonary disease or asthma bronchiale) on stroke severity and outcome.

Results

Co-existing CIAD was evident in 7.1 % (n = 72) of all patients with acute ischemic stroke. Baseline characteristics of stroke patients with CIAD did not differ significantly from ischemic stroke patients without CIAD. Age (OR 1.17 [95 % CI 1.03-1.37] per decade), atrial fibrillation (OR 3.43 [95 % CI 2.47-4.78]) and coronary artery disease (OR 1.51 [95 % CI 1.07–2.14]) but not a history of CIAD (p = 0.30) were associated with severe stroke (NIHSS≥11) on hospital admission. Age (HR 1.70 [95 % CI 1.53-1.87] per decade), peripheral artery disease (HR 1.91 [95 % CI 1.35-2.7]), stroke severity at hospital admission (NIHSS per point HR 1.08 [95 % CI 1.06-1.10]), and history of CIAD (HR 1.43 [95 % CI 1.02-2.00]) were independently associated with mortality during long-term follow-up. However, CIAD was not significantly associated with short-term mortality after stroke.

Conclusion

Co-existing CIAD showed no significant association with stroke severity at hospital admission and early mortality after ischemic stroke. CIAD was negatively associated with long-term survival after ischemic stroke.

A psychometric assessment of the St. George's respiratory questionnaire in patients with COPD using Rasch model analysis

BACKGROUND

The St. George's Respiratory Questionnaire (SGRQ) was a widely used tool to assess disease impact on patients with obstructive airways disease. Although traditional methods have generally supported construct validity and internal consistency reliability of SGRQ, such methods cannot facilitate the evaluation of whether items are equivalent to different individuals. The purpose of this study is to rigorously examine the psychometric properties of the SGRQ in patients with chronic obstructive pulmonary disease (COPD) using Rasch model analysis.

METHODS

A methodological research was conducted on SGRQ in a sample of 240 male patients with COPD recruited from the outpatient services in Central Taiwan. The psychometric properties of the SGRQ were examined using Rasch model analysis with a mixed rating scale and partial credit mode by Winsteps software. The level of matching between the item's difficulty and person's ability was analyzed by item-person targeting as well as ceiling and floor effects. Item-person maps were also examined for checking the location of the item's difficulty and person's measures along the same scale. Finally, the differential item functioning (DIF) was examined to measure group equivalence associated with age and disease's severity.

RESULTS

Each of the three domains (Symptom, Activity, Impact) of the SGRQ was found to be unidimensionality. The person separation index ranged from 1.21 (Symptom domain) to 2.50 (Activity domain). There was a good targeting for the SGRQ domains, except the Impact domain (1.36). The percentage of ceiling and floor effects were below 10%, except the ceiling effect in the Impact domain (26.25%). From item-person maps, gaps of location of item corresponded to patient's ability were identified. The results have also showed that many items in SGRQ revealed age or severity related DIF.

CONCLUSIONS

Except the Symptom domain of SGRQ, the others have a reliabile internal consistency and a good hierarchical structure. The results of Rasch model analysis can highlight aspects for scale improvement, such as gap, duplicate items or scale responses. There was some age or severity related DIF indicating somewhat unstable across different characteristics of group. IRB No.: DMR94-IRB-179.

Development of a modified BODE index as a mortality risk measure among older adults with and without chronic obstructive pulmonary disease

The BODE index was developed as a prognostic mortality risk tool for persons with chronic obstructive pulmonary disease (COPD). It incorporates 4 measures: body mass index, lung obstruction, dyspnea, and exercise capacity. The intent of this study was to examine how well a BODE-like index constructed using a simpler lung function measure, peak expiratory flow, in combination with physical functioning and symptom information more readily found in survey data (a quasi-BODE index), performs in identifying persons at higher risk of mortality and whether it may be extended as an assessment of mortality risk to persons without diagnosed COPD. Using US national survey data from the Health Retirement Study for 2006-2010, each unit increase in the quasi-BODE index score was associated with a multiplicative 50% increase in mortality risk (odds ratio = 1.50, 95% confidence interval: 1.41, 1.59). The quasi-BODE index is a multidimensional health status instrument based on the BODE index, which is a good predictor of mortality. The quasi-BODE index was compiled using simple measures of physical and respiratory function. It is a potentially useful prognostic instrument for older adult populations with or without COPD, including those with severe physical limitations, particularly when combined with demographic factors and comorbid conditions.

Discharge coordinator intervention prevents hospitalizations in patients with COPD: a randomized controlled trial

OBJECTIVES

To test whether coordination of discharge from hospital reduces hospitalizations in patients with chronic obstructive pulmonary disease (COPD).

DESIGN

Randomized controlled clinical trial.

SETTING

Specialized pulmonary hospital.

PARTICIPANTS

Patients hospitalized for an acute exacerbation of COPD.

INTERVENTION

Care as usual included routine patient education, supervised inhaler use, respiratory physiotherapy, and disease-related communication. The discharge coordinator intervention added assessment of patient situation and homecare needs. Patients and caregivers were actively involved and empowered in the discharge planning process, which was communicated with community medical professionals to provide continuity of care at home.

MEASUREMENTS

The primary end-point of the study was the number of patients hospitalized because of worsening COPD. Key secondary end-points were time-to-COPD hospitalization, all-cause mortality, all-cause hospitalization, days alive and out of hospital, and health-related quality of life.

RESULTS

Of 253 eligible patients (71 ± 9 years, 72% men, 87% GOLD III/IV), 118 were assigned to intervention and 135 to usual care. During a follow-up of 180 days, fewer patients receiving intervention were hospitalized for COPD (14% versus 31%, P = .002) or for any cause (31% versus 44%, P = .033). In time-to-event analysis, intervention was associated with lower rates of COPD hospitalizations (P = .001). A Cox model of proportional hazards, adjusted for sex, age, GOLD stage, heart failure, malignant disease, and long-term oxygen treatment, demonstrated that intervention reduced the risk of COPD hospitalization (hazard ratio 0.43, 95% confidence interval 0.24-0.77, P = .002).

CONCLUSION

Among patients hospitalized for acute COPD exacerbation, discharge coordinator intervention reduced both COPD hospitalizations and all-cause hospitalizations.

Chronic obstructive pulmonary disease is associated with low levels of vitamin D

Introduction

COPD patients may be at increased risk for vitamin D (25(OH)D) deficiency, but risk factors for deficiency among COPD patients have not been extensively reported.

Methods

Serum 25(OH)D levels were measured by liquid chromatography double mass spectrometry in subjects aged 40–76 years from Western Norway, including 433 COPD patients (GOLD stage II-IV) and 325 controls. Levels <20 ng/mL defined deficiency. Season, sex, age, body mass index (BMI), smoking, GOLD stage, exacerbation frequency, arterial oxygen tension (PaO₂), respiratory symptoms, depression (CES-D score≥16), comorbidities (Charlson score), treatment for osteoporosis, use of inhaled steroids, and total white blood count were examined for associations with 25(OH)D in both linear and logistic regression models.

Results

COPD patients had an increased risk for vitamin D deficiency compared to controls after adjustment for seasonality, age, smoking and BMI. Variables associated with lower 25(OH)D levels in COPD patients were obesity ( = −6.63), current smoking ( = −4.02), GOLD stage III- IV ( = −4.71, = −5.64), and depression ( = −3.29). Summertime decreased the risk of vitamin D deficiency (OR = 0.22).

Conclusion

COPD was associated with an increased risk of vitamin D deficiency, and important disease characteristics were significantly related to 25(OH)D levels.

Antibiotics as immunomodulant agents in COPD

It is widely accepted that some antibiotics have activities beyond their direct antibacterial effects. Macrolide is the antibiotic class with more convincing studies and evidence on its immunomodulatory and anti-inflammatory activities. Different clinical studies have shown that macrolide prophylaxis in patients with moderate-severe chronic obstructive pulmonary disease (COPD) can have a significant impact on the exacerbation rate reducing morbidity and, potentially, mortality of the disease. Other antibiotics, such as fluoroquinolones, demonstrate a variety of immunomodulatory effects but only few clinical data are available in COPD. New macrolide derivatives devoid of antibacterial activity have been synthetized. This review analyses the relevance of immunomodulatory and anti-inflammatory effects of antibiotics in the management of COPD.

Effect of five genetic variants associated with lung function on the risk of chronic obstructive lung disease, and their joint effects on lung function

RATIONALE

Genomic loci are associated with FEV1 or the ratio of FEV1 to FVC in population samples, but their association with chronic obstructive pulmonary disease (COPD) has not yet been proven, nor have their combined effects on lung function and COPD been studied.

OBJECTIVES

To test association with COPD of variants at five loci (TNS1, GSTCD, HTR4, AGER, and THSD4) and to evaluate joint effects on lung function and COPD of these single-nucleotide polymorphisms (SNPs), and variants at the previously reported locus near HHIP.

METHODS

By sampling from 12 population-based studies (n = 31,422), we obtained genotype data on 3,284 COPD case subjects and 17,538 control subjects for sentinel SNPs in TNS1, GSTCD, HTR4, AGER, and THSD4. In 24,648 individuals (including 2,890 COPD case subjects and 13,862 control subjects), we additionally obtained genotypes for rs12504628 near HHIP. Each allele associated with lung function decline at these six SNPs contributed to a risk score. We studied the association of the risk score to lung function and COPD.

MEASUREMENTS AND MAIN RESULTS

Association with COPD was significant for three loci (TNS1, GSTCD, and HTR4) and the previously reported HHIP locus, and suggestive and directionally consistent for AGER and TSHD4. Compared with the baseline group (7 risk alleles), carrying 10-12 risk alleles was associated with a reduction in FEV1 (β = -72.21 ml, P = 3.90 × 10(-4)) and FEV1/FVC (β = -1.53%, P = 6.35 × 10(-6)), and with COPD (odds ratio = 1.63, P = 1.46 × 10(-5)).

CONCLUSIONS

Variants in TNS1, GSTCD, and HTR4 are associated with COPD. Our highest risk score category was associated with a 1.6-fold higher COPD risk than the population average score.

Telomere dysfunction causes sustained inflammation in chronic obstructive pulmonary disease

RATIONALE

Chronic obstructive pulmonary disease (COPD) is associated with chronic inflammation of unknown pathogenesis.

OBJECTIVES

To investigate whether telomere dysfunction and senescence of pulmonary vascular endothelial cells (P-ECs) induce inflammation in COPD.

METHODS

Prospective comparison of patients with COPD and age- and sex-matched control smokers. Investigation of mice null for telomerase reverse transcriptase (Tert) or telomerase RNA component (Terc) genes.

MEASUREMENTS AND MAIN RESULTS

In situ lung specimen studies showed a higher percentage of senescent P-ECs stained for p16 and p21 in patients with COPD than in control subjects. Cultured P-ECs from patients with COPD exhibited early replicative senescence, with decreased cell-population doublings, a higher percentage of β-galactosidase-positive cells, reduced telomerase activity, shorter telomeres, and higher p16 and p21 mRNA levels at an early cell passage compared with control subjects. Senescent P-ECs released cytokines and mediators: the levels of IL-6, IL-8, monocyte chemotactic protein (MCP)-1, Hu-GRO, and soluble intercellular adhesion molecule (sICAM)-1 were elevated in the media of P-ECs from patients compared with control subjects at an early cell passage, in proportion to the senescent P-EC increase and telomere shortening. Up-regulation of MCP-1 and sICAM-1 led to increased monocyte adherence and migration. The elevated MCP-1, IL-8, Hu-GROα, and ICAM-1 levels measured in lungs from patients compared with control subjects correlated with P-EC senescence criteria and telomere length. In Tert(-/-) and/or Terc(-/-) mouse lungs, levels of the corresponding cytokines (MCP-1, IL-8, Hu-GROα, and ICAM-1) were also altered, despite the absence of external stimuli and in proportion to telomere dysfunction.

CONCLUSIONS

Telomere dysfunction and premature P-EC senescence are major processes perpetuating lung inflammation in COPD.

Cigarette smoke induces the release of CXCL-8 from human bronchial epithelial cells via TLRs and induction of the inflammasome

COPD is a chronic airway disease associated with inflammation and cigarette smoking. Airway epithelial cells are the first cells exposed to cigarette smoke (CS) and can release CXCL-8 and IL-1β. These cytokines are involved in acute and chronic inflammatory processes in COPD. The aim of this study was to investigate whether toll-like receptors (TLRs) located in/on epithelial cells were involved in cigarette smoke-induced cytokine production. Here we demonstrate that CS induces the release of CXCL-8 and IL-1β from human bronchial epithelial cells (HBE-14o). CS-induced CXCL-8 production was inhibited by an antibody against TLR4 and by inhibitory ODN suggesting the involvement of TLR4 and TLR9. In addition, exposure of HBE-14o cells to TLR4 or TLR9 ligands resulted in the release of CXCL-8 and IL1β. TLR4 and also TLR9 were present on the cell surface and the expression of both receptors decreased after CS exposure. The molecular mechanism of the CS-induced CXCL-8 production by the epithelial cells was further investigated. It was found that P2X7 receptors and reactive oxygen species were involved. Interestingly, the inflammasome activator monosodium urate crystals (MSU) induced the release of CXCL-8 and IL-1β and the caspase-1 inhibitor Z-VADDCB suppressed the CS-induced release of CXCL-8. In addition, CS, CpGODN, lipopolysaccharide and MSU all increased the expression of caspase-1 and IL-1β. In conclusion, our results demonstrate that CS releases CXCL-8 from HBE-14o cells via TLR4 and TLR9 and inflammasome activation. Therefore, inflammasome signaling in airway epithelial cells may play an important role in pathogenesis of diseases like COPD.

NRF2 targeting: a promising therapeutic strategy in chronic obstructive pulmonary disease

Several convergent destructive mechanisms such as oxidative stress, alveolar cell apoptosis, extracellular matrix proteolysis and chronic inflammation contribute to chronic obstructive pulmonary disease (COPD) development. Evidence suggests that oxidative stress contributes to the pathophysiology of COPD, particularly during exacerbations. Nuclear factor erythroid-2-related factor 2 (NRF2), a transcription factor expressed predominantly in epithelium and alveolar macrophages, has an essential protective role in the lungs through the activation of antioxidant response element-regulated antioxidant and cytoprotective genes. Animal models and human studies have identified NRF2 and several NRF2 target genes as a protective system against inflammation and oxidative stress from cigarette smoke, a major causative factor in COPD development. Hence, NRF2 targeting might provide clinical benefit by reducing both oxidative stress and inflammation in COPD.

Vitamin D deficiency and chronic obstructive pulmonary disease: a vicious circle

Vitamin D and vitamin D deficiency strongly interact with different pathogenic mechanisms in COPD. Prevalence of vitamin D deficiency is particularly high in COPD patients, increases with the severity of COPD, and is closely associated with osteoporosis prevalence. Adequate calcium and vitamin D supplementation in COPD patients with documented deficiencies reduces the risk for falling and osteoporotic fractures, may indirectly reduce morbidity, and may potentially prevent the further deterioration of pulmonary function. Apart from the proven beneficial effects of vitamin D supplements on bone and muscle tissue, many epidemiological studies have putatively linked vitamin D deficiency with a higher risk for cardiovascular, inflammatory and infectious diseases, and cancer, diseases known to be associated with and to contribute significantly to the phenotypic presentation of COPD patients. Different animal and human studies have provided considerable evidence on how vitamin D may affect these processes. The burning question in COPD is whether prevention of vitamin D deficiency or adequate supplementation may reverse the natural course of the disease.

Targeting maladaptive glutathione responses in lung disease

The lung is unique being exposed directly to the atmospheric environment containing xenobiotics, pathogens, and other agents which are continuously inhaled on a daily basis. Additionally, the lung is exposed to higher ambient oxygen levels which can promote the formation of a complex number of reactive oxygen and nitrogen species. Due to this constant barrage of potential damaging agents, the lung has developed a high degree of plasticity in dealing with ever changing conditions. In the present commentary, we will focus on glutathione (GSH) as a key antioxidant in the lung airways and discuss mechanisms by which the lung uses GSH to adapt to its rapidly changing environment. We will then examine the evidence on how defective and inadequate adaptive responses can lead to lung injury, inflammation and disease. Lastly, we will examine some of the recent attempts to alter lung GSH levels with therapies in a number of human lung diseases and discuss some of the limitations of such approaches.