A Randomized, Placebo-controlled Trial of Roflumilast. Effect on Proline-Glycine-Proline and Neutrophilic Inflammation in Chronic Obstructive Pulmonary Disease

Immunomodulatory Effects of Fluoroquinolones in Community-Acquired Pneumonia-Associated Acute Respiratory Distress Syndrome

Community-acquired pneumonia is reported as one of the infectious diseases that leads to the development of acute respiratory distress syndrome. The innate immune system is the first line of defence against microbial invasion; however, its dysregulation during infection, resulting in an increased pathogen load, stimulates the over-secretion of chemokines and pro-inflammatory cytokines. This phenomenon causes damage to the epithelial-endothelial barrier of the pulmonary alveoli and the leakage of the intravascular protein into the alveolar lumen. Fluoroquinolones are synthetic antimicrobial agents with immunomodulatory properties that can inhibit bacterial proliferation as well as exhibit anti-inflammatory activities. It has been demonstrated that the structure of fluoroquinolones, particularly those with a cyclopropyl group, exerts immunomodulatory effects. Its capability to inhibit phosphodiesterase activity leads to the accumulation of intracellular cAMP, which subsequently enhances PKA activity, resulting in the inhibition of transcriptional factor NF-κB and the activation of CREB. Another mechanism reported is the inhibition of TLR and ERK signalling pathways. Although the sequence of events has not been completely understood, significant progress has been made in comprehending the specific mechanisms underlying the immunomodulatory effects of fluoroquinolones. Here, we review the indirect immunomodulatory effects of FQs as an alternative to empirical therapy in patients diagnosed with community-acquired pneumonia.

Synergistic Pulmonoprotective Effect of Natural Prolyl Oligopeptidase Inhibitors in In Vitro and In Vivo Models of Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is a highly morbid inflammatory lung disease with limited pharmacological interventions. The present study aims to evaluate and compare the potential pulmonoprotective effects of natural prolyl oligopeptidase (POP) inhibitors namely rosmarinic acid (RA), chicoric acid (CA), epigallocatechin-3-gallate (EGCG) and gallic acid (GA), against lipopolysaccharide (LPS)-induced ARDS. Cell viability and expression of pro-inflammatory mediators were measured in RAW264.7 cells and in primary murine lung epithelial and bone marrow cells. Nitric oxide (NO) production was also assessed in unstimulated and LPS-stimulated RAW264.7 cells. For subsequent in vivo experiments, the two natural products (NPs) with the most favorable effects, RA and GA, were selected. Protein, cell content and lipid peroxidation levels in bronchoalveolar lavage fluid (BALF), as well as histopathological changes and respiratory parameters were evaluated in LPS-challenged mice. Expression of key mediators involved in ARDS pathophysiology was detected by Western blotting. RA and GA favorably reduced gene expression of pro-inflammatory mediators in vitro, while GA decreased NO production in macrophages. In LPS-challenged mice, RA and GA co-administration improved respiratory parameters, reduced cell and protein content and malondialdehyde (MDA) levels in BALF, decreased vascular cell adhesion molecule-1 (VCAM-1) and the inducible nitric oxide synthase (iNOS) protein expression, activated anti-apoptotic mechanisms and down-regulated POP in the lung. Conclusively, these synergistic pulmonoprotective effects of RA and GA co-administration could render them a promising prophylactic/therapeutic pharmacological intervention against ARDS.

Apremilast ameliorates acute respiratory distress syndrome by inhibiting neutrophil-induced oxidative stress

BACKGROUND

The pathogenesis of acute respiratory distress syndrome (ARDS) is attributed to the dysregulation of oxidative stress and neutrophil recruitment. We aimed to investigate the anti-inflammatory effects of apremilast on human neutrophils and assess its efficacy for treating ARDS.

METHODS

We analysed superoxide anion generation, integrin expression, and adhesion in activated human neutrophils using spectrophotometry, flow cytometry, and immunofluorescence microscopy. Phosphorylation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) was determined using immunoblotting. A murine lipopolysaccharide (LPS)-induced ARDS model was used to evaluate the therapeutic effects of apremilast.

RESULTS

Apremilast significantly decreased superoxide anion production, reactive oxygen species (ROS) generation, cluster of differentiation (CD)11 b expression, and neutrophil adhesion in formyl-l-methionyl-l-leucyl-l-phenylalanine activated human neutrophils. Apremilast elevated cyclic 3',5'-adenosine monophosphate (cAMP) and protein kinase A (PKA) activity in activated neutrophils. It reduced cellular cAMP-specific phosphodiesterase (PDE) activity and selectively inhibited enzymatic PDE4 activity. The activated cAMP/PKA pathway suppressed the phosphorylation of ERK and JNK as well as Ca2+ mobilization in activated neutrophils. All inhibitory effects of apremilast on activated neutrophils were reversed by a PKA inhibitor. In vivo examinations indicated that apremilast alleviated lung neutrophil infiltration, myeloperoxidase (MPO) activity, pulmonary oedema, and alveolar damage in LPS-induced ARDS.

CONCLUSION

Apremilast inhibits inflammatory responses after neutrophil activation via cAMP/PKA-dependent inhibition of ERK and JNK activation. Our study revealed apremilast suppresses oxidative stress and chemotaxis by selectively inhibiting PDE4 in neutrophils and thus protects against endotoxin-induced ARDS in mice. Apremilast can be used as an alternative off-label drug in treating acute lung damage.

cAMP-PDE signaling in COPD: Review of cellular, molecular and clinical features

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death among non-contagious diseases in the world. PDE inhibitors are among current medicines prescribed for COPD treatment of which, PDE-4 family is the predominant PDE isoform involved in hydrolyzing cyclic adenosine monophosphate (cAMP) that regulates the inflammatory responses in neutrophils, lymphocytes, macrophages and epithelial cells The aim of this study is to investigate the cellular and molecular mechanisms of cAMP-PDE signaling, as an important pathway in the treatment management of patients with COPD. In this review, a comprehensive literature review was performed about the effect of PDEs in COPD. Generally, PDEs are overexpressed in COPD patients, resulting in cAMP inactivation and decreased cAMP hydrolysis from AMP. At normal amounts, cAMP is one of the essential agents in regulating metabolism and suppressing inflammatory responses. Low amount of cAMP lead to activation of downstream inflammatory signaling pathways. PDE4 and PDE7 mRNA transcript levels were not altered in polymorphonuclear leukocytes and CD8 lymphocytes originating from the peripheral venous blood of stable COPD subjects compared to healthy controls. Therefore, cAMP-PDE signaling pathway is one of the most important signaling pathways involved in COPD. By examining the effects of different drugs in this signaling pathway critical steps can be taken in the treatment of this disease.

Pharmacologic Management Strategies of Asthma-Chronic Obstructive Pulmonary Disease Overlap

The best therapeutic approach to patients with asthma-chronic obstructive pulmonary disease overlap (ACO) is unknown. Current treatment recommendations rely on expert opinions, roundtable discussions, and strategy documents, because patients with ACO have been excluded from most clinical studies in asthma and COPD. Because of the underlying asthma initial therapy, early use of inhaled corticosteroids along with a long-acting bronchodilator is recommended. If maintenance inhaler therapy is not effective, advanced therapies based on phenotyping and identification of treatable traits may be considered.

More than a random association between chronic obstructive pulmonary disease and psoriatic arthritis: shared pathogenic features and implications for treatment

INTRODUCTION

Psoriatic arthritis (PsA) is a chronic inflammatory condition characterized by skin and joints involvement, and with a great burden of comorbidity that could affect the choice of treatment. Chronic obstructive pulmonary disease (COPD) is one of the primary causes of morbidity and mortality. Medical therapy can improve symptoms and the frequency and severity of exacerbations. A variety of evidence showed an increasing association between COPD and PsA.

AREAS COVERED

Psoriatic disease and COPD appear to have a possible pathophysiologic link. The inhibition of intracellular molecules responsible for pro-inflammatory responses could be a therapeutic approach for both psoriatic diseases and COPD. Inhibitors of phosphodiesterase 4 (PDE-4) were developed to treat chronic inflammatory conditions such as psoriasis, PsA and COPD. Roflumilast has been used to treat COPD and asthma, while Apremilast to treat psoriasis and PsA. Given the efficacy and safety of these treatments, we can speculate that blocking PDE-4 might also provide clinical benefits in patients with co-existing COPD and PsA.

EXPERT OPINION

This hypothesis could offer the opportunity to screen patients for both diseases. Furthermore, this approach would increase the involvement of other specialists in the management of PsA, and it would improve the use of a tailored treatment for each patient.

Effectiveness of Roflumilast in Treating Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis

Background

Chronic obstructive pulmonary disease (COPD) is a chronic airflow obstructive condition. The mainstay of treatment is to avoid exacerbation and manage the symptoms. Roflumilast is being used as a part of treatment to reduce the inflammatory process in this disease.

Method

This systematic review and meta-analysis were conducted following the provided guidelines. PubMed, Cochrane Library, and Cinahl were considered for searching the desired studies selected until 19 June 2021. The eligibility criteria for inclusion and exclusion were set before selecting studies.

Result

Five hundred eighty (580) studies were identified at the beginning. Removal of duplicates was done using Endnote software. The eligibility criteria, including the randomized controlled trial study design and others, were applied for screening the title and abstracts. Six studies were selected for the qualitative analysis. After assessing the data from these studies, it was found that roflumilast is an effective drug to treat COPD. Roflumilast plays an essential role in improving quality of life, inflammatory process, and clinical improvement. The drug's mild to moderate adverse effects were observed, but no significant severe adverse events were reported, and the drug was well tolerated.

Conclusion

Roflumilast is a valuable drug that can be used for its beneficial effects on COPD exacerbation. The benefits of the drug outweigh its adverse effects.

Current Status of the Use of Multifunctional Enzymes as Anti-Cancer Drug Targets

Fighting cancer is one of the major challenges of the 21st century. Among recently proposed treatments, molecular-targeted therapies are attracting particular attention. The potential targets of such therapies include a group of enzymes that possess the capability to catalyze at least two different reactions, so-called multifunctional enzymes. The features of such enzymes can be used to good advantage in the development of potent selective inhibitors. This review discusses the potential of multifunctional enzymes as anti-cancer drug targets along with the current status of research into four enzymes which by their inhibition have already demonstrated promising anti-cancer effects in vivo, in vitro, or both. These are PFK-2/FBPase-2 (involved in glucose homeostasis), ATIC (involved in purine biosynthesis), LTA₄H (involved in the inflammation process) and Jmjd6 (involved in histone and non-histone posttranslational modifications). Currently, only LTA₄H and PFK-2/FBPase-2 have inhibitors in active clinical development. However, there are several studies proposing potential inhibitors targeting these four enzymes that, when used alone or in association with other drugs, may provide new alternatives for preventing cancer cell growth and proliferation and increasing the life expectancy of patients.

Imperatorin Alleviates Psoriasiform Dermatitis by Blocking Neutrophil Respiratory Burst, Adhesion, and Chemotaxis Through Selective Phosphodiesterase 4 Inhibition

Aim: Neutrophil infiltration and increased oxidative stress are involved in the pathogenesis and severity of psoriasis. Although the therapy of psoriasis remains elusive, targeting treatment to reduce oxidative stress is considered a potential option. Our study demonstrates the anti-inflammatory effects of a natural furocoumarin, imperatorin, on activated human neutrophils and psoriasiform dermatitis in mice. Results: Imperatorin inhibited superoxide anion generation, neutrophil adhesion, and migration in N-formyl-l-methionyl-l-leucyl-l-phenylalanine (fMLF)-stimulated human neutrophils. Further studies showed that imperatorin induced a decrease in cAMP-specific phosphodiesterase (PDE) activity, and increased intracellular cAMP levels and protein kinase A (PKA) activity in human neutrophils. The enzyme activities of PDE4 subtypes, but not PDE3 and PDE7, were inhibited by imperatorin. Furthermore, imperatorin inhibited the phosphorylation of protein kinase B (Akt), extracellular regulated kinase (ERK), and c-Jun N-terminal kinase (JNK), as well as Ca²⁺ mobilization in fMLF-stimulated neutrophils. These suppressive effects of imperatorin on cell responses and signaling were reversed by PKA inhibitor, suggesting that cAMP/PKA is involved in the anti-inflammatory effects of imperatorin. In vivo studies of imiquimod- and interleukin-23-induced mouse psoriasiform dermatitis demonstrated that imperatorin alleviated skin desquamation, epidermal thickening, keratinocyte hyperproliferation, and neutrophil infiltration. Innovation and Conclusion: Our results demonstrate that imperatorin inhibits human neutrophil respiratory burst, adhesion, and migration through the elevation of cAMP/PKA to inhibit Akt, ERK, JNK, and Ca²⁺ mobilization. Imperatorin is a natural inhibitor of PDE4A/B/C and may serve as a lead for developing new therapeutics to treat neutrophilic psoriasis. Antioxid. Redox Signal. 35, 885-903.

Phosphodiesterase-4 Inhibitors for Non-COPD Respiratory Diseases

Selective phosphodiesterase (PDE) inhibitors are a class of nonsteroid anti-inflammatory drugs for treating chronic inflammatory diseases. Modulation of systemic and airway inflammation is their pivotal mechanism of action. Furthermore, PDE inhibitors modulate cough reflex and inhibit airway mucus secretion. Roflumilast, a selective PDE4 inhibitor, has been extensively studied for the efficacy and safety in chronic obstructive pulmonary disease (COPD) patients. According to the mechanisms of action, the potential roles of PDE inhibitors in treating chronic respiratory diseases including severe asthma, asthma-COPD overlap (ACO), noncystic fibrosis bronchiectasis, and chronic cough are discussed. Since roflumilast inhibits airway eosinophilia and neutrophilia in COPD patients, it reduces COPD exacerbations in the presence of chronic bronchitis in addition to baseline therapies. The clinical studies in asthma patients have shown the comparable efficacy of roflumilast to inhaled corticosteroids for improving lung function. However, the clinical trials of roflumilast in severe asthma have been limited. Although ACO is common and is also associated with poor outcomes, there is no clinical trial regarding its efficacy in patients with ACO despite a promising role in reducing COPD exacerbation. Since mucus hypersecretion is a result of neutrophil secretagogue in patients with chronic bronchitis, experimental studies have shown that PDE4s are regulators of the cystic fibrosis transmembrane conductance regulator (CFTR) in human airway epithelial cells. Besides, goblet cell hyperplasia is associated with an increased expression of PDE. Bronchiectasis and chronic bronchitis are considered neutrophilic airway diseases presenting with mucus hypersecretion. They commonly coexist and thus lead to severe disease. The role of roflumilast in noncystic fibrosis bronchiectasis is under investigation in clinical trials. Lastly, PDE inhibitors have been shown modulating cough from bronchodilation, suppressing transient receptors potential (TRP), and anti-inflammatory properties. Hence, there is the potential role of the drug in the management of unexplained cough. However, clinical trials for examining its antitussive efficacy are pivotal. In conclusion, selective PDE4 inhibitors may be potential treatment options for chronic respiratory diseases apart from COPD due to their promising mechanisms of action.

The Counter Regulatory Axis of the Lung Renin-Angiotensin System in Severe COVID-19: Pathophysiology and Clinical Implications

The severe acute respiratory syndrome coronavirus (SARS-CoV)-2, which is responsible for coronavirus disease 2019 (COVID-19), uses angiotensin (ANG)-converting enzyme 2 (ACE2) as the entrance receptor. Although most COVID-19 cases are mild, some are severe or critical, predominantly due to acute lung injury. It has been widely accepted that a counter regulatory renin-angiotensin system (RAS) axis including the ACE2/ANG [1-7]/Mas protects the lungs from acute lung injury. However, recent evidence suggests that the generation of protective ANG [1-7] in the lungs is predominantly mediated by proinflammatory prolyl oligopeptidase (POP), which has been repeatedly demonstrated to be involved in lung pathology. This review contends that acute lung injury in severe COVID-19 is characterised by a) ACE2 downregulation and malfunction (inflammatory signalling) due to viral occupation, and b) dysregulation of the protective RAS axis, predominantly due to increased activity of proinflammatory POP. It follows that a reasonable treatment strategy in COVID-19-related acute lung injury would be delivering functional recombinant (r) ACE2 forms to trap the virus. Additionally, or alternatively to rACE2 delivery, the potential benefits resulting from lowering POP activity should also be explored. These treatment strategies deserve further investigation.

Clinical Relevance of the Anti-inflammatory Effects of Roflumilast on Human Bronchus: Potentiation by a Long-Acting Beta-2-Agonist

Background: Roflumilast is an option for treating patients with severe COPD and frequent exacerbations despite optimal therapy with inhaled drugs. The present study focused on whether the phosphodiesterase (PDE) 4 inhibitor roflumilast and its active metabolite roflumilast N-oxide affect the release of tumor necrosis factor (TNF)-α and chemokines by lipopolysaccharide (LPS)-stimulated human bronchial explants. We also investigated the interactions between roflumilast, roflumilast N-oxide and the β₂-agonist formoterol with regard to cytokine release by the bronchial preparations.

Methods: Bronchial explants from resected lungs were incubated with roflumilast, roflumilast N-oxide and/or formoterol and then stimulated with LPS. An ELISA was used to measure levels of TNF-α and chemokines in the culture supernatants.

Results: At a clinically relevant concentration (1 nM), roflumilast N-oxide and roflumilast consistently reduced the release of TNF-α, CCL2, CCL3, CCL4, CCL5 and CXCL9 (but not CXCL1, CXCL5, CXCL8 and IL-6) from human bronchial explants. Formoterol alone decreased the release of TNF-α, CCL2, and CCL3. The combination of formoterol with roflumilast (1 nM) was more potent than roflumilast alone for inhibiting the LPS-induced release of TNF-α, CCL2, CCL3, CCL4, and CXCL9 by the bronchial explants.

Conclusions: At a clinically relevant concentration, roflumilast N-oxide and its parent compound, roflumilast, reduced the LPS-induced production of TNF-α and chemokines involved in monocyte and T-cell recruitment but did not alter the release of chemokines involved in neutrophil recruitment. The combination of formoterol with roflumilast enhanced the individual drugs’ anti-inflammatory effects.

Roflumilast in Severely Ill Patients with Chronic Obstructive Pulmonary Disease with Frequent Exacerbations: Risk of Pneumonia Hospitalization and Severe Exacerbations

Roflumilast is given as an add-on to inhalation medication in patients with chronic obstructive pulmonary disease (COPD) and chronic bronchitis. Animal experiments have documented deleterious effects of roflumilast in bacterial infections, but trials have not reported the risk of bacterial infections in patients. The objective of this study is to determine, among outpatients with severe COPD in a two-year follow-up period, the risk of hospitalization-requiring pneumonia, severe acute exacerbation in COPD (AECOPD-hosp), and death. Patients with COPD using roflumilast (roflumilast users) were compared to a propensity score-matched COPD control group not using roflumilast (non-roflumilast users). Roflumilast users had an increased 2-year risk of hospitalization-requiring pneumonia (HR 1.5, 95% CI 1.3 to 1.8, p-value < 0.0001) compared to controls, and of AECOPD-Hosp (hazard ratio(HR) 1.6, 95%, confidence interval (CI) 1.5 to 1.8, p-value < 0.0001) and. When adding an active comparator (theophylline) as a matching variable, the signal was largely unchanged. In conclusion, roflumilast was associated with an increased number of hospitalizations for pneumonia and for AECOPD. Since trials have not reported risks of bacterial complications and data regarding severe exacerbations in roflumilast users are sparse and diverging, these data are concerning. Trials focused on the risk of pneumonia, AECOPD, and other bacterial infections in roflumilast users are needed urgently.

Extracellular matrix-derived peptides in tissue remodeling and fibrosis

Alterations in the composition of the extracellular matrix (ECM) critically regulate the cellular responses in tissue repair, remodeling, and fibrosis. After injury, proteolytic degradation of ECM generates bioactive ECM fragments, named matricryptins, exposing cryptic sites with actions distinct from the parent molecule. Matricryptins contribute to the regulation of inflammatory, reparative, and fibrogenic cascades through effects on several different cell types both in acute and chronic settings. Fibroblasts play a major role in matricryptin generation not only as the main cellular source of ECM proteins, but also as producers of matrix-degrading proteases. Moreover, several matricryptins exert fibrogenic or reparative actions by modulating fibroblast phenotype and function. This review manuscript focuses on the mechanisms of matricyptin generation in injured and remodeling tissues with an emphasis on fibroblast-matricryptin interactions.

Phosphodiesterase-4 inhibitors for chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with cough, sputum production or dyspnoea, and a reduction in lung function, quality of life, and life expectancy. Apart from smoking cessation, no other treatments that slow lung function decline are available. Roflumilast and cilomilast are oral phosphodiesterase-4 (PDE₄) inhibitors proposed to reduce the airway inflammation and bronchoconstriction seen in COPD. This Cochrane Review was first published in 2011, and was updated in 2017 and 2020.

OBJECTIVES

To evaluate the efficacy and safety of oral PDE₄ inhibitors for management of stable COPD.

SEARCH METHODS

We identified randomised controlled trials (RCTs) from the Cochrane Airways Trials Register (date of last search 9 March 2020). We found other trials at web-based clinical trials registers.

SELECTION CRITERIA

We included RCTs if they compared oral PDE₄ inhibitors with placebo in people with COPD. We allowed co-administration of standard COPD therapy.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Two independent review authors selected trials for inclusion, extracted data, and assessed risk of bias. We resolved discrepancies by involving a third review author. We assessed our confidence in the evidence by using GRADE recommendations. Primary outcomes were change in lung function (minimally important difference (MID) = 100 mL) and quality of life (scale 0 to 100; higher score indicates more limitations).

MAIN RESULTS

We found 42 RCTs that met the inclusion criteria and were included in the analyses for roflumilast (28 trials with 18,046 participants) or cilomilast (14 trials with 6457 participants) or tetomilast (1 trial with 84 participants), with a duration between six weeks and one year or longer. These trials included people across international study centres with moderate to very severe COPD (Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades II to IV), with mean age of 64 years. We judged risks of selection bias, performance bias, and attrition bias as low overall amongst the 39 published and unpublished trials. Lung function Treatment with a PDE₄ inhibitor was associated with a small, clinically insignificant improvement in forced expiratory volume in one second (FEV₁) over a mean of 40 weeks compared with placebo (mean difference (MD) 49.33 mL, 95% confidence interval (CI) 44.17 to 54.49; participants = 20,815; studies = 29; moderate-certainty evidence). Forced vital capacity (FVC) and peak expiratory flow (PEF) were also improved over 40 weeks (FVC: MD 86.98 mL, 95% CI 74.65 to 99.31; participants = 22,108; studies = 17; high-certainty evidence; PEF: MD 6.54 L/min, 95% CI 3.95 to 9.13; participants = 4245; studies = 6; low-certainty evidence). Quality of life Trials reported improvements in quality of life over a mean of 33 weeks (St George's Respiratory Questionnaire (SGRQ) MD -1.06 units, 95% CI -1.68 to -0.43; participants = 7645 ; moderate-certainty evidence). Incidence of exacerbations Treatment with a PDE₄ inhibitor was associated with a reduced likelihood of COPD exacerbation over a mean of 40 weeks (odds ratio (OR) 0.78, 95% CI 0.73 to 0.84; participants = 20,382; studies = 27; high-certainty evidence), that is, for every 100 people treated with PDE₄ inhibitors, five more remained exacerbation-free during the study period compared with those given placebo (number needed to treat for an additional beneficial outcome (NNTB) 20, 95% CI 16 to 27). No change in COPD-related symptoms nor in exercise tolerance was found. Adverse events More participants in the treatment groups experienced an adverse effect compared with control participants over a mean of 39 weeks (OR 1.30, 95% CI 1.22 to 1.38; participants = 21,310; studies = 30; low-certainty evidence). Participants experienced a range of gastrointestinal symptoms such as diarrhoea, nausea, vomiting, or dyspepsia. Diarrhoea was more commonly reported with PDE₄ inhibitor treatment (OR 3.20, 95% CI 2.74 to 3.50; participants = 20,623; studies = 29; high-certainty evidence), that is, for every 100 people treated with PDE₄ inhibitors, seven more suffered from diarrhoea during the study period compared with those given placebo (number needed to treat for an additional harmful outcome (NNTH) 15, 95% CI 13 to 17). The likelihood of psychiatric adverse events was higher with roflumilast 500 µg than with placebo (OR 2.13, 95% CI 1.79 to 2.54; participants = 11,168; studies = 15 (COPD pool data); moderate-certainty evidence). Roflumilast in particular was associated with weight loss during the trial period and with an increase in insomnia and depressive mood symptoms. Participants treated with PDE₄ inhibitors were more likely to withdraw from trial participation; on average, 14% in the treatment groups withdrew compared with 8% in the control groups. Mortality No effect on mortality was found (OR 0.98, 95% CI 0.77 to 1.24; participants = 19,786; studies = 27; moderate-certainty evidence), although mortality was a rare event during these trials.

AUTHORS' CONCLUSIONS

For this current update, five new studies from the 2020 search contributed to existing findings but made little impact on outcomes described in earlier versions of this review. PDE₄ inhibitors offered a small benefit over placebo in improving lung function and reducing the likelihood of exacerbations in people with COPD; however, they had little impact on quality of life or on symptoms. Gastrointestinal adverse effects and weight loss were common, and the likelihood of psychiatric symptoms was higher, with roflumilast 500 µg. The findings of this review provide cautious support for the use of PDE₄ inhibitors in COPD. In accordance with GOLD 2020 guidelines, they may have a place as add-on therapy for a subgroup of people with persistent symptoms or exacerbations despite optimal COPD management (e.g. people whose condition is not controlled by fixed-dose long-acting beta₂-agonist (LABA) and inhaled corticosteroid (ICS) combinations). More longer-term trials are needed to determine whether or not PDE₄ inhibitors modify FEV₁ decline, hospitalisation, or mortality in COPD.

Role of phosphodiesterase-4 inhibitors in chronic obstructive pulmonary disease

Phosphodiesterase-4 inhibitors (PDE4Is) are potent anti-inf lammatory agents and roflumilast has been used to prevent acute exacerbation of chronic obstructive pulmonary disease (COPD). Roflumilast decreases neutrophil migration, restores cystic fibrosis transmembrane conductance regulator activity, and recovers glucocorticoid effects. A forced expiratory volume in 1 second of < 50%, a chronic bronchitis phenotype, high blood eosinophil levels, and a history of hospitalization are biomarkers for predicting responses to roflumilast. Adverse effects are common in clinical practice. An inhaled PDE4I has recently been developed and is under clinical trial. CHF6001 and RPL554 exhibit promise and may be future treatment options for COPD.

The matrikine acetyl-proline-glycine-proline and clinical features of COPD: findings from SPIROMICS

BACKGROUND

Pulmonary and systemic inflammation are central features of chronic obstructive pulmonary disease (COPD). Previous studies have demonstrated relationships between biologically active extracellular matrix components, or matrikines, and COPD pathogenesis. We studied the relationships between the matrikine acetyl-proline-glycine-proline (AcPGP) in sputum and plasma and clinical features of COPD.

METHODS

Sputum and plasma samples were obtained from COPD participants in the SPIROMICS cohort at enrollment. AcPGP was isolated using solid phase extraction and measured by mass spectrometry. Demographics, spirometry, quality of life questionnaires, and quantitative computed tomography (CT) imaging with parametric response mapping (PRM) were obtained at baseline. Severe COPD exacerbations were recorded at 1-year of prospective follow-up. We used linear and logistic regression models to measure associations between AcPGP and features of COPD, and Kaplan-Meier analyses to measure time-to-first severe exacerbation.

RESULTS

The 182 COPD participants in the analysis were 66 ± 8 years old, 62% male, 84% White race, and 39% were current smokers. AcPGP concentrations were 0.61 ± 1.89 ng/mL (mean ± SD) in sputum and 0.60 ± 1.13 ng/mL in plasma. In adjusted linear regression models, sputum AcPGP was associated with FEV₁/FVC, spirometric GOLD stage, PRM-small airways disease, and PRM-emphysema. Sputum AcPGP also correlated with severe AECOPD, and elevated sputum AcPGP was associated with shorter time-to-first severe COPD exacerbation. In contrast, plasma AcPGP was not associated with symptoms, pulmonary function, or severe exacerbation risk.

CONCLUSIONS

In COPD, sputum but not plasma AcPGP concentrations are associated with the severity of airflow limitation, small airways disease, emphysema, and risk for severe AECOPD at 1-year of follow-up.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01969344 (SPIROMICS).

An extracellular matrix fragment drives epithelial remodeling and airway hyperresponsiveness

It is anticipated that bioactive fragments of the extracellular matrix (matrikines) can influence the development and progression of chronic diseases. The enzyme leukotriene A₄ hydrolase (LTA₄H) mediates opposing proinflammatory and anti-inflammatory activities, through the generation of leukotriene B₄ (LTB₄) and degradation of proneutrophilic matrikine Pro-Gly-Pro (PGP), respectively. We show that abrogation of LTB₄ signaling ameliorated inflammation and airway hyperresponsiveness (AHR) in a murine asthma model, yet global loss of LTA₄H exacerbated AHR, despite the absence of LTB₄ This exacerbated AHR was attributable to a neutrophil-independent capacity of PGP to promote pathological airway epithelial remodeling. Thus, we demonstrate a disconnect between airway inflammation and AHR and the ability of a matrikine to promote an epithelial remodeling phenotype that negatively affects lung function. Subsequently, we show that substantial quantities of PGP are detectable in the sputum of moderate-severe asthmatics in two distinct cohorts of patients. These studies have implications for our understanding of remodeling phenotypes in asthma and may rationalize the failure of LTA₄H inhibitors in the clinic.

Acute Exacerbation of Chronic Obstructive Pulmonary Disease and Subsequent Risk of Emergency Department Visits and Hospitalizations for Atrial Fibrillation

Background Although emerging evidence has suggested the relationship of chronic obstructive pulmonary disease with atrial fibrillation (AF), little is known about whether acute exacerbation of chronic obstructive pulmonary disease (AECOPD) increases the risk of repeated AF-related healthcare utilization. Methods This is a self-controlled case series study using the population-based emergency department (ED) and inpatient databases of 5 US states from 2007 through 2012. Among patients with existing AF, we identified patients with an AECOPD hospitalization and at least 1 ED visit or hospitalization for AF during the observation period. We constructed conditional Poisson regression models to compare the rate of AF-related ED visits or hospitalizations during sequential 90-day periods after the AECOPD hospitalization, with pre-AECOPD days 1 to 90 as the reference. Results We analyzed 944 patients who were hospitalized for AECOPD and had an ED visit or hospitalization for AF during a 450-day period. The median age was 77 years, and 41% were men. Compared with the reference period, the rate of AF-related ED visits or hospitalizations significantly increased in the post-AECOPD days 1 to 90 (7.3 versus 14.1 per 100 person-months; rate ratio, 1.93; 95% CI, 1.63-2.29; P<0.001). Then, the rate decreased to the reference level in the post-AECOPD days 91 to 180 (7.5 per 100 person-months; rate ratio, 1.03; 95% CI, 0.85-1.25; P=0.77) and remained at the reference level during post-AECOPD days 181 to 270 (rate ratio, 0.84; 95% CI, 0.68-1.03; P=0.09) and days 271 to 360 (rate ratio, 0.90; 95% CI, 0.73-1.10; P=0.29). These temporal associations persisted with stratification by age, sex, and season. Conclusions Among patients with existing AF, AECOPD was associated with a higher risk of AF-related ED visit or hospitalization in the first 90-day post-AECOPD period.

Management of asthma COPD overlap

OBJECTIVE

To review the latest literature on management approaches to patients with asthma chronic obstructive pulmonary disease (COPD) overlap (ACO).

DATA SOURCES

Studies and reports were identified from the databases of PubMed/Medline and ClinicalTrials.gov from the US National Institutes of Health and the Cochrane Register of Controlled Trials.

STUDY SELECTIONS

Studies on the management of asthma, COPD, and ACO were included in this review.

RESULTS

Patients with asthma COPD overlap tend to have greater morbidity than those with asthma or COPD alone, but the information on the best therapeutic approach to this group of patients is still limited. Current treatment recommendations rely on expert opinions, roundtable discussions, and strategy documents, because most clinical studies in asthma and COPD have excluded patients with ACO. Because of the potential risk described in patients with asthma with the use of long-acting 2 agonist monotherapy, initial therapy for patients with ACO is recommended to include a long-acting bronchodilator in conjunction with inhaled corticosteroids. Long-acting muscarinic antagonists are effective in both asthma and COPD and should be considered in ACO as an add-on treatment. If inhaler therapy is not effective, advanced therapies based on phenotyping and identification of treatable traits may be considered.

CONCLUSION

Few studies have evaluated prospectively therapies in the ACO population, and future studies need to determine best strategies for the treatment of these patients, focusing on targeting its different phenotypes and its treatable traits.

Abnormal pro-gly-pro pathway and airway neutrophilia in pediatric cystic fibrosis

BACKGROUND

Proline-glycine-proline (PGP) is a bioactive fragment of collagen generated by the action of matrix metalloproteinase-9 (MMP-9) and prolylendopeptidase (PE), and capable of eliciting neutrophil chemotaxis and epithelial remodelling. PGP is normally then degraded by leukotriene A₄ hydrolase (LTA₄H) to limit inflammation and remodelling. This study hypothesized that early and persistent airway neutrophilia in Cystic Fibrosis (CF) may relate to abnormalities in the PGP pathway and sought to understand underlying mechanisms.

METHODS

Broncho-alveolar lavage (BAL) fluid was obtained from 38 CF (9 newborns and 29 older children) and 24 non-CF children. BAL cell differentials and levels of PGP, MMP-9, PE and LTA₄H were assessed.

RESULTS

Whilst PGP was present in all but one of the older CF children tested, it was absent in non-CF controls and the vast majority of CF newborns. BAL levels of MMP-9 and PE were elevated in older children with CF relative to CF newborns and non-CF controls, correlating with airway neutrophilia and supportive of PGP generation. Furthermore, despite extracellular LTA₄H commonly being greatly elevated concomitantly with inflammation to promote PGP degradation, this was not the case in CF children, potentially owing to degradation by neutrophil elastase.

CONCLUSIONS

A striking imbalance between PGP-generating and -degrading enzymes enables PGP accumulation in CF children from early life and potentially supports airway neutrophilia.

The Effects of Safflower Yellow on Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Randomized, Controlled Clinical Trial

Objectives

To evaluate the efficacy of safflower yellow in the acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Methods

In a prospective, randomized, controlled trial, 127 patients who met the inclusion criteria were enrolled and were randomly divided into two groups. The control group included 64 patients treated according to the global strategy for diagnosis, management, and prevention of COPD (www.goldcopd.org, updated 2011). The intervention group included 63 patients who received intravenous infusions of safflower yellow (100 mg of safflower yellow dissolved in 250 ml 0.9% saline) once daily for 14 consecutive days in addition to standard diagnosis and treatment. The difference in the average length of the hospital stay between the two groups of patients was determined. The follow-up period was 28 days; the differences in symptoms, clinical indicators, and 28-day mortality in the two groups were compared. Statistical analysis was conducted using SPSS 22.0 software to determine whether there were statistically significant differences (P <0.05) between groups.

Results

There were no statistically significant differences between the intervention group and the control group in changes in secondary indicators. There were no statistically significant differences in the 28-day mortality or in the survival curves of the two groups (P=0.496 and P=0.075, respectively). Safflower yellow treatment of AECOPD may relieve the patient's clinical symptoms, such as dyspnoea, shorten the average length of hospital stay (P=0.006, respectively), and decrease the duration of mechanical ventilation.

Conclusion

Safflower yellow in the treatment of AECOPD has a degree of clinical value. This trial is registered under the identifier ChiCTR-IPR-17014176.

NETopathic Inflammation in Chronic Obstructive Pulmonary Disease and Severe Asthma

Neutrophils play a central role in innate immunity, inflammation, and resolution. Unresolving neutrophilia features as a disrupted inflammatory process in the airways of patients with chronic obstructive pulmonary disease (COPD) and severe asthma. The extent to which this may be linked to disease pathobiology remains obscure and could be further confounded by indication of glucocorticoids or concomitant respiratory infections. The formation of neutrophil extracellular traps (NETs) represents a specialized host defense mechanism that entrap and eliminate invading microbes. NETs are web-like scaffolds of extracellular DNA in complex with histones and neutrophil granular proteins, such as myeloperoxidase and neutrophil elastase. Distinct from apoptosis, NET formation is an active form of cell death that could be triggered by various microbial, inflammatory, and endogenous or exogenous stimuli. NETs are reportedly enriched in neutrophil-dominant refractory lung diseases, such as COPD and severe asthma. Evidence for a pathogenic role for respiratory viruses (e.g., Rhinovirus), bacteria (e.g., Staphylococcus aureus) and fungi (e.g., Aspergillus fumigatus) in NET induction is emerging. Dysregulation of this process may exert localized NET burden and contribute to NETopathic lung inflammation. Disentangling the role of NETs in human health and disease offer unique opportunities for therapeutic modulation. The chemokine CXCR2 receptor regulates neutrophil activation and migration, and small molecule CXCR2 antagonists (e.g., AZD5069, danirixin) have been developed to selectively block neutrophilic inflammatory pathways. NET-stabilizing agents using CXCR2 antagonists are being investigated in proof-of-concept studies in patients with COPD to provide mechanistic insights. Clinical validation of this type could lead to novel therapeutics for multiple CXCR2-related NETopathologies. In this Review, we discuss the emerging role of NETs in the clinicopathobiology of COPD and severe asthma and provide an outlook on how novel NET-stabilizing therapies via CXCR2 blockade could be leveraged to disrupt NETopathic inflammation in disease-specific phenotypes.

Effects of Roflumilast on Rehospitalization and Mortality in Patients

Introduction: Hospitalization for chronic obstructive pulmonary disease (COPD) exacerbation portends the greatest risk of rehospitalization and mortality. Treatments that prevent hospitalizations could significantly lessen COPD morbidity and mortality. Methods: We performed a prospective, randomized, double-blind, placebo-controlled study of roflumilast 500 ug daily versus placebo in patients hospitalized for acute COPD exacerbation. Primary outcome was time to all-cause mortality or non-elective rehospitalization at 180 days post-randomization. Secondary outcomes were death or hospitalization from a respiratory cause, quality of life, change in health status, forced expiratory volume in 1 second (FEV1) and roflumilast tolerance. Results: A total of 64 patients with moderate to severe COPD (FEV1, 37.6 ± 16.4% predicted; 61% female, 61.6 ± 7.9 years old) were assigned to roflumilast or placebo. No deaths occurred in the follow-up period. There was no difference in the time to first readmission between the roflumilast and placebo groups (46.1 days versus 47.3 days respectively, p=0.93). There were 29 and 30 readmissions in the roflumilast and placebo groups, respectively (p=0.47). The St George's Respiratory Questionnaire (SGRQ) decreased 10.8 points and 7.8 points in the roflumilast and placebo groups, respectively and were not different. EuroQuality of Life Five Dimension scale (EQ5D) scores improved, but not significantly in either group. Weight loss and nausea were more common with roflumilast but not different from placebo. Change in glycosylated hemoglobin percentage (HgbA1C%) was not different between groups. Sub-analysis for the impact of chronic bronchitis did not affect outcomes. Conclusion: In this pilot study conducted in patients hospitalized with an exacerbation of COPD, roflumilast did not affect time to all-cause rehospitalization, quality of life, FEV1 or any other measured parameter.

Neutrophil Elastase Inhibitors and Chronic Kidney Disease

End-stage renal disease (ESRD), the last stage of chronic kidney disease (CKD), is characterized by chronic inflammation and oxidative stress. Neutrophils are the front line cells that mediate an inflammatory response against microorganisms as they can migrate, produce reactive oxygen species (ROS), secrete neutrophil serine proteases (NSPs), and release neutrophil extracellular traps (NETs). Serine proteases inhibitors regulate the activity of serine proteases and reduce neutrophil accumulation at inflammatory sites. This review intends to relate the role of neutrophil elastase in CKD and the effects of neutrophil elastase inhibitors in predicting or preventing inflammation.

The multifaceted roles of the matrikine Pro-Gly-Pro in pulmonary health and disease

Matrikines are bioactive fragments of the extracellular matrix (ECM) that are fundamental in regulating a diverse array of physiological processes. The tripeptide Proline-Glycine-Proline (PGP) is a collagen-derived matrikine that has classically been described as a neutrophil chemoattractant. In this article, we describe our current understanding of the pathways that generate, degrade and modify PGP to dictate its bioavailability and stability. Additionally, we discuss our expanding appreciation of the capacity of PGP to regulate diverse cell types and biological processes, independent of its activity on neutrophils, including a putative role in wound repair. We argue that PGP functions as a primitive and conserved damage-associated molecular pattern, which is generated during infection or injury and subsequently acts to shape ensuing inflammatory and repair processes. As a fragment of the ECM that accumulates at the epicentre of the action, PGP is perfectly positioned to focus neutrophils to the exact site required and direct a localised repair response. However, it is essential that PGP is efficiently degraded, as if this matrikine is allowed to persist then pathology can ensue. Accordingly, we discuss how this pathway is subverted in chronic lung diseases giving rise to persistent inflammation and pathological tissue remodelling.

Clinical utility of blood neutrophil-lymphocyte ratio in Japanese COPD patients

Background

Neutrophil-to-lymphocyte ratio (NLR) is a biomarker of inflammation in chronic obstructive pulmonary disease (COPD) patients. But, a meaningful threshold and the longitudinal changes are unknown. We aimed to investigate the association between NLR and the clinical characteristics of COPD patients and to determine a meaningful threshold and the longitudinal changes for NLR.

Methods

Keio University and its affiliate hospitals conducted an observational COPD cohort study over 3 years. We performed a blood examination and a pulmonary function test. Blood examination was completed at baseline and annually thereafter, at a time when the disease was stable. Two hundred seventy-four patients who had at least 3 blood examinations over 3 years were included.

Results

Baseline NLR was correlated with baseline C-reactive protein (CRP) (r = 0.18, p = 0.003) and SAA (r = 0.34, p <  0.001). We defined an NLR score of 2.7 as the arbitrary cut-off value based on upper quartile points. COPD patients with NLR ≥ 2.7 were older (p = 0.037), had a lower BMI (p = 0.005) and a lower %FEV1 (p = 0.0003) compared to patients with NLR < 2.7. Receiver-operating-characteristic (ROC) curves showed the optimal cutoff for the baseline NLR in the predicting moderate/severe exacerbation to be 2.7, which was same as the upper quartile points. Follow-up analysis over 3 years revealed that the differences in the trends of NLR among the three groups based on the categories of exacerbations (moderate or severe, mild, no exacerbation) were significant (p = 0.006).

Conclusions

NLR is associated with COPD severity and exacerbations. For predicting exacerbations, we estimated the threshold of NLR to be 2.7 at baseline.

Trial registration

Clinical trial registered with the University Hospital Medication Information Network (UMIN000003470, April 10, 2010).

Electronic supplementary material

The online version of this article (10.1186/s12890-018-0639-z) contains supplementary material, which is available to authorized users.

Cilostazol, a phosphodiesterase 3 inhibitor, activates proteasome-mediated proteolysis and attenuates tauopathy and cognitive decline

Alzheimer's disease and several variants of frontotemporal degeneration including progressive supranuclear palsy and corticobasal degeneration are characterized by the accumulation of abnormal tau protein into aggregates. Most proteins, including tau, are degraded via the ubiquitin proteasome system, but when abnormal tau accumulates, the function of 26S proteasomes is downregulated. The negative effect of tau aggregates on the function of the proteasome can have deleterious consequences on protein homeostasis and disease progression. Developing therapies aimed at clearing abnormal tau are thus of considerable interest. In the present study, we investigated the effect of cilostazol, an FDA-approved selective phosphodiesterase 3 inhibitor, on a mouse model of tauopathy (line rTg4510). Administration of cilostazol for 30 days enhanced proteasome function via the cyclic adenosine 3',5'-monophosphate/protein kinase A pathway and attenuated tauopathy and cognitive decline in rTg4510 mice. These results suggest that cilostazol, or other FDA-approved drugs acting via the same pathway, has the potential to be repurposed for the treatment of patients with early-stage tauopathy.

Effect of roflumilast on chronic obstructive pulmonary disease: a systematic review and meta-analysis

BACKGROUND

Randomized controlled trials (RCTs) of roflumilast effect on chronic obstructive pulmonary disease (COPD) have been reported in the last decade. The current meta-analysis was designed to systematically review and perform meta-analysis of the RCTs of roflumilast treatment in COPD.

METHODS

Electronic databases including PubMed, EMBASE, Web of Science, and Cochrane clinical trials database were searched to identify RCTs of roflumilast treatment on COPD. The primary outcomes were effect of roflumilast on pre-bronchodilator FEV1, post-bronchodilator FEV1, and exacerbation rate. Secondary outcomes were effect of roflumilast on airway inflammation and adverse effect.

RESULTS

A total of 11 RCTs were enrolled into the current analysis. Roflumilast significantly improved both pre-bronchodilator FEV1 (standardized difference in mean ± SD was 0.621 ± 0.161; 95% CI 0.306~0.936, p < 0.001) and post-bronchodilator FEV1 (standardized difference in mean ± SD was 0.563 ± 0.149, 95% CI 0.270~0.855, p < 0.001) compared with placebo. Roflumilast also significantly reduced exacerbation of COPD (standardized difference in mean ± SD 0.099 ± 0.020, 95% CI 0.061~0.138; p < 0.001) and suppressed airway inflammation (standardized difference in mean ± SD 1.354 ± 0.260, 95% CI 0.845~1.862, p < 0.001) compared with placebo. However, roflumilast significantly increased adverse effect such as diarrhea (rate ratio 2.945, 95% CI 2.453~3.536, p < 0.001) and weight loss (rate ratio 3.814, 95% CI 3.091~4.707, p < 0.001) compared with placebo.

CONCLUSION

These findings indicated that roflumilast treatment could improve COPD patients' lung function and reduce exacerbation, and that inhibition of airway inflammation by roflumilast might contribute to the beneficial effect of PDE-4 inhibitors on COPD.

Angiotensin-converting enzyme defines matrikine-regulated inflammation and fibrosis

The neutrophil chemoattractant proline-glycine-proline (PGP) is generated from collagen by matrix metalloproteinase-8/9 (MMP-8/9) and prolyl endopeptidase (PE), and it is concomitantly degraded by extracellular leukotriene A₄ hydrolase (LTA₄H) to limit neutrophilia. Components of cigarette smoke can acetylate PGP, yielding a species (AcPGP) that is resistant to LTA₄H-mediated degradation and can, thus, support a sustained neutrophilia. In this study, we sought to elucidate if an antiinflammatory system existed to degrade AcPGP that is analogous to the PGP-LTA₄H axis. We demonstrate that AcPGP is degraded through a previously unidentified action of the enzyme angiotensin-converting enzyme (ACE). Pulmonary ACE is elevated during episodes of acute inflammation, as a consequence of enhanced vascular permeability, to ensure the efficient degradation of AcPGP. Conversely, we suggest that this pathway is aberrant in chronic obstructive pulmonary disease (COPD) enabling the accumulation of AcPGP. Consequently, we identify a potentially novel protective role for AcPGP in limiting pulmonary fibrosis and suggest the pathogenic function attributed to ACE in idiopathic pulmonary fibrosis (IPF) to be a consequence of overzealous AcPGP degradation. Thus, AcPGP seemingly has very divergent roles: it is pathogenic in its capacity to drive neutrophilic inflammation and matrix degradation in the context of COPD, but it is protective in its capacity to limit fibrosis in IPF.

ACE degrades the collagen-derived matrikine, acetylate proline–glycine–proline, to limit pulmonary inflammation and promote repair.

Phosphodiesterase 4 inhibitors for chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with cough, sputum production or dyspnoea and a reduction in lung function, quality of life and life expectancy. Apart from smoking cessation, there are no other treatments that slow lung function decline. Roflumilast and cilomilast are oral phosphodiesterase 4 (PDE4) inhibitors proposed to reduce the airway inflammation and bronchoconstriction seen in COPD. This is an update of a Cochrane review first published in 2011 and updated in 2013.

OBJECTIVES

To evaluate the efficacy and safety of oral PDE4 inhibitors in the management of stable COPD.

SEARCH METHODS

We identified randomised controlled trials (RCTs) from the Cochrane Airways Trials Register (date of last search October 2016). We found other trials from web-based clinical trials registers.

SELECTION CRITERIA

We included RCTs if they compared oral PDE4 inhibitors with placebo in people with COPD. We allowed co-administration of standard COPD therapy.

DATA COLLECTION AND ANALYSIS

One review author extracted data and a second review author checked the data. We reported pooled data in Review Manager as mean differences (MD), standardised mean differences (SMD) or odds ratios (OR). We converted the odds ratios into absolute treatment effects in a 'Summary of findings' table.

MAIN RESULTS

Thirty-four separate RCTs studying roflumilast (20 trials with 17,627 participants) or cilomilast (14 trials with 6457 participants) met the inclusion criteria, with a duration of between six weeks and one year. These included people across international study centres with moderate to very severe COPD (Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades II-IV), with a mean age of 64 years.We considered that the methodological quality of the 34 published and unpublished trials was acceptable overall. Treatment with a PDE4 inhibitor was associated with a significant improvement in forced expiratory volume in one second (FEV1) over the trial period compared with placebo (MD 51.53 mL, 95% confidence interval (CI) 43.17 to 59.90, 27 trials with 20,585 participants, moderate-quality evidence due to moderate levels of heterogeneity and risk of reporting bias). There were small improvements in quality of life (St George's Respiratory Questionnaire (SGRQ), MD -1.06 units, 95% CI -1.68 to -0.43, 11 trials with 7645 participants, moderate-quality evidence due to moderate levels of heterogeneity and risk of reporting bias) and COPD-related symptoms, but no significant change in exercise tolerance. Treatment with a PDE4 inhibitor was associated with a reduced likelihood of COPD exacerbation (OR 0.78, 95% CI 0.73 to 0.83; 23 trials with 19,948 participants, high-quality evidence). For every 100 people treated with PDE4 inhibitors, five more remained exacerbation-free during the study period compared with placebo (number needed to treat for an additional beneficial outcome (NNTB) 20, 95% CI 16 to 26). More participants in the treatment groups experienced non-serious adverse events compared with controls, particularly a range of gastrointestinal symptoms such as diarrhoea, nausea, vomiting or dyspepsia. For every 100 people treated with PDE4 inhibitors, seven more suffered from diarrhoea during the study period compared with placebo (number needed to treat for an additional harmful outcome (NNTH) 15, 95% CI 13 to 17). Roflumilast in particular was associated with weight loss during the trial period and an increase in insomnia and depressive mood symptoms. There was no significant effect of treatment on non-fatal serious adverse events (OR 0.99, 95% CI 0.91 to 1.07) or mortality (OR 0.97, 95% CI 0.76 to 1.23), although mortality was a rare event during the trials. Participants treated with PDE4 inhibitors were more likely to withdraw from the trials because of adverse effects; on average 14% in the treatment groups withdrew compared with 8% in the control groups.

AUTHORS' CONCLUSIONS

In people with COPD, PDE4 inhibitors offered benefit over placebo in improving lung function and reducing the likelihood of exacerbations; however, they had little impact on quality of life or symptoms. Gastrointestinal adverse effects and weight loss were common, and safety data submitted to the US Food and Drug Administration (FDA) have raised concerns over psychiatric adverse events with roflumilast. The findings of this review give cautious support to the use of PDE4 inhibitors in COPD. They may be best used as add-on therapy in a subgroup of people with persistent symptoms or exacerbations despite optimal COPD management. This is in accordance with the GOLD 2017 guidelines. Longer-term trials are needed to determine whether or not PDE4 inhibitors modify FEV1 decline, hospitalisation or mortality in COPD.

Roflumilast treatment inhibits lung carcinogenesis in benzo(a)pyrene-induced murine lung cancer model

Roflumilast, a potent and selective inhibitor of phosphodiesterase-4 (PDE4), has been used in treatment of COPD. PDE4 inhibitor is associated with inhibition of chronic airway inflammation, oxidative stress, and mesenchymal markers in B(a)P-induced lung tumors. The aim of this study was to assess whether roflumilast alone or added to inhaled budesonide might have dose-dependent inhibition on lung carcinogenesis induced by carcinogen B(a)P in mice. Female A/J mice were given a single dose of benzo(a)pyrene. Administration of roflumilast (1mg/kg or 5mg/kg) via oral gavage and aerosolized budesonide (2.25mg/ml) began 2 weeks post-carcinogen treatment and continued for 26 weeks. Tumor load was determined by averaging the total tumor volume in each group. Benzo(a)pyrene induced an average tumor size of 9.38 ± 1.75 tumors per mouse, with an average tumor load of 19.53 ± 3.81mm³. Roflumilast 5mg/kg treatment decreased (P < 0.05) tumor load per mouse compared to the B(a)P group. Roflumilast 5mg/kg treatment significantly increased the levels of cAMP in tumors with adjacent lung tissues (P < 0.05). The expression level of PDE4D gene was decreased by roflumilast 5mg/kg treatment, significantly (P < 0.05). Compared to the B(a)P exposure group, expression levels of HIF-1α and VEGFA were attenuated by roflumilast 5mg/kg treatment (P < 0.05). High-dose roflumilast can attenuate lung carcinogenesis in B(a)P-induced murine lung cancer model. The chemopreventive effect of roflumilast might be associated with inhibition of increased cAMP-mediated inflammatory process and markers of angiogenesis in tumor tissues.

The development of novel LTA4H modulators to selectively target LTB4 generation

The pro-inflammatory mediator leukotriene B₄ (LTB₄) is implicated in the pathologies of an array of diseases and thus represents an attractive therapeutic target. The enzyme leukotriene A₄ hydrolase (LTA₄H) catalyses the distal step in LTB₄ synthesis and hence inhibitors of this enzyme have been actively pursued. Despite potent LTA₄H inhibitors entering clinical trials all have failed to show efficacy. We recently identified a secondary anti-inflammatory role for LTA₄H in degrading the neutrophil chemoattractant Pro-Gly-Pro (PGP) and rationalized that the failure of conventional LTA₄H inhibitors may be that they inadvertently prevented PGP degradation. We demonstrate that these inhibitors do indeed fail to discriminate between the dual activities of LTA₄H, and enable PGP accumulation in mice. Accordingly, we have developed novel compounds that potently inhibit LTB₄ generation whilst leaving PGP degradation unperturbed. These novel compounds could represent a safer and superior class of LTA₄H inhibitors for translation into the clinic.

Bioactive extracellular matrix fragments in lung health and disease

The extracellular matrix (ECM) is the noncellular component critical in the maintenance of organ structure and the regulation of tissue development, organ structure, and cellular signaling. The ECM is a dynamic entity that undergoes continuous degradation and resynthesis. In addition to compromising structure, degradation of the ECM can liberate bioactive fragments that cause cellular activation and chemotaxis of a variety of cells. These fragments are termed matrikines, and their cellular activities are sentinel in the development and progression of tissue injury seen in chronic lung disease. Here, we discuss the matrikines that are known to be active in lung biology and their roles in lung disease. We also consider the use of matrikines as disease markers and potential therapeutic targets in lung disease.

Multifaceted effects of Francisella tularensis on human neutrophil function and lifespan

Francisella tularensis in an intracellular bacterial pathogen that causes a potentially lethal disease called tularemia. Studies performed nearly 100 years ago revealed that neutrophil accumulation in infected tissues correlates directly with the extent of necrotic damage during F. tularensis infection. However, the dynamics and details of bacteria-neutrophil interactions have only recently been studied in detail. Herein, we review current understanding regarding the mechanisms that recruit neutrophils to F. tularensis-infected lungs, opsonization and phagocytosis, evasion and inhibition of neutrophil defense mechanisms, as well as the ability of F. tularensis to prolong neutrophil lifespan. In addition, we discuss distinctive features of the bacterium, including its ability to act at a distance to alter overall neutrophil responsiveness to exogenous stimuli, and the evidence which suggests that macrophages and neutrophils play distinct roles in tularemia pathogenesis, such that macrophages are major vehicles for intracellular growth and dissemination, whereas neutrophils drive tissue destruction by dysregulation of the inflammatory response.

Fine-tuning neutrophil activation: Strategies and consequences

In spite of their important role in host defense, neutrophils can also cause severe morbidity and mortality. Neutrophils have an extensive armory necessary to eradicate pathogens, but neutrophil infiltration and activation also induces major tissue injury associated with acute and chronic inflammatory disorders. Here, we review neutrophil anti-microbial functions and discuss their individual contribution to disease pathogenesis. Furthermore, we provide an overview of the anti-inflammatory drugs that can dampen neutrophil transmigration, elastase activity, and the production of reactive oxygen species which are already in clinical trials. The discovery of potential inhibitors of the release of neutrophil extracellular trap is still in its infancy. Here, we discuss small molecule inhibitors and inhibitory receptors that show promising results in reducing neutrophil extracellular trap formation in vitro and in vivo and discuss the advantages and drawbacks of inhibiting the release of neutrophil extracellular traps as a therapeutic treatment. Specific suppression of neutrophil extracellular trap formation, preferably while other antimicrobial functions are preserved, would be an ideal approach to treat neutrophilic inflammation, since it prevents acute as well as chronic neutrophil-associated pathology.

Can roflumilast, a phosphodiesterase-4 inhibitor, improve clinical outcomes in patients with moderate-to-severe chronic obstructive pulmonary disease? A meta-analysis

Background

Effects of roflumilast on lung function, symptoms, acute exacerbation and adverse events in patients with chronic obstructive pulmonary disease (COPD) are controversial. We aimed to further clarify the efficacy and safety of roflumilast in treatment of moderate-to-severe COPD.

Methods

From 1946 to November 2015, we searched the Pubmed, Embase, Medline, Cochrane Central Register of Controlled Trials, ISI Web of Science and American College of Physician using “roflumilast” and “chronic obstructive pulmonary disease” or “COPD”. Randomized controlled trials that reported forced expiratory volume in one second (FEV₁), forced vital capacity (FVC), transition dyspnea index (TDI), St George’s Respiratory Questionnaire (SGRQ), and incidence of COPD exacerbations and adverse events were eligible. We conducted the heterogeneities test and sensitivity analysis, and random-effects or fixed-effects model was applied to calculate risk ratio (RR) and mean difference (MD) for dichotomous and continuous data respectively. Cochrane systematic review software, Review Manager (RevMan), was used to test the hypothesis by Mann-Whitney U-test.

Results

Thirteen trials with a total of 14,563 patients were pooled in our final studies. Except for SGRQ (I² = 63 %, χ² = 1.71, P = 0.07) and adverse events (I² = 94 %, χ² = 0.03, P < 0.001), we did not find statistical heterogeneity in outcome measures. The pooled MD of pre- and post-bronchodilator FEV₁ was 54.60 (95 % confidence interval (CI) 46.02 ~ 63.18) and 57.86 (95 % CI 49.80 ~ 65.91), and both showed significant improvement in patients with roflumilast (z = 12.47, P <0.001; z = 14.07, P < 0.001), so did in FVC (MD 90.37, 95 % CI 73.95 ~ 106.78, z = 10.79, P < 0.001). Significant alleviation of TDI (MD 0.30, 95 % CI 0.14 ~ 0.46, z = 3.67, P < 0.001) and decrease of acute exacerbation (RR 0.86, 95 % CI 0.81 ~ 0.91, z = 5.54, P < 0.001) were also identified in treatment of roflumilast, but without significant difference in SGRQ (MD −1.30, 95 % CI −3.16 ~ 0.56, z = 1.37, P = 0.17). Moreover, roflumilast significantly increased the incidence of adverse events compared with placebo (RR 1.31, 95 % CI 1.16 ~ 1.47, z = 4.32, P < 0.001).

Conclusions

Roflumilast can be considered as an alternative therapy in selective patients with moderate-to-severe COPD.