S. Marchand-Adam

Extracellular ATP Is a Danger Signal Activating P2X7 Receptor in Lung Inflammation and Fibrosis

RATIONALE Pulmonary fibrosis is a devastating as yet untreatable disease. We previously investigated the endogenous mediators released on lung injury and showed that uric acid is a danger signal activating Nod-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome in lung inflammation and fibrosis (Gasse et al., Am J Respir Crit Care Med 2009;179:903-913). OBJECTIVES Here we address the role of extracellular adenosine triphosphate (eATP) in pulmonary inflammation and fibrosis. METHODS ATP was quantified in bronchoalveolar lavage fluid (BALF) of control subjects and patients with idiopathic pulmonary fibrosis. The contribution of eATP as a danger signal was assessed in a murine model of lung fibrosis induced by airway-administered bleomycin (BLM), an intercalating agent that causes DNA strand breaks. MEASUREMENTS AND MAIN RESULTS Fibrotic patients have elevated ATP content in BALF in comparison with control individuals. In mice, we report an early increase in eATP levels in BALF on BLM administration. Modulation of eATP levels with the ATP-degrading enzyme apyrase greatly reduced BLM-induced inflammatory cell recruitment, lung IL-1β, and tissue inhibitor of metalloproteinase (TIMP)-1 production, while administration of ATP-γS, a stable ATP derivative, enhanced inflammation. P2X(7) receptor-deficient mice presented dramatically reduced lung inflammation, with reduced fibrosis markers such as lung collagen content and matrix-remodeling proteins TIMP-1 and matrix metalloproteinase-9. The acute inflammation depends on a functional pannexin-1 hemichannel protein. In vitro, ATP is released by pulmonary epithelial cells on BLM-induced stress and this is partly dependent on the presence of functional P2X(7) receptor and pannexin-1 hemichannel. CONCLUSIONS ATP released from BLM-injured lung cells constitutes a major endogenous danger signal that engages the P2X(7) receptor/pannexin-1 axis, leading to IL-1β maturation and lung fibrosis.

Cutting Edge: Nonproliferating Mature Immune Cells Form a Novel Type of Organized Lymphoid Structure in Idiopathic Pulmonary Fibrosis

Ectopic formation of secondary lymphoid tissue is initiated by the local attraction of naive T and B cells. In this study, we describe a novel type of organized lymphoid structure in the lung of human idiopathic pulmonary fibrosis, with key features of lymphoid neogenesis, including: 1) recently activated CD40 ligand (CD40L)+ T cells; 2) variable numbers of activated CD40+/CD40L+ B cells, sometimes organized in follicles; 3) fully mature dendritic cells (DC) expressing CD40, CD83, CD86, and DC-lysosome-associated membrane protein; 4) the expression of the chemokine CCL21; 5) the presence of vessels with characteristics of high endothelial venules; and 6) a dense network of follicular DC. Surprisingly, these structures are devoid of CCR7+ naive T cells, proliferating lymphocytes, and germinal centers, suggesting that newly recruited activated DC and Ag-experienced lymphocytes can drive lymphoid neogenesis and that factors present within the lymphoid aggregates, such as CD40L, are essential to induce DC maturation.

Comorbidities of COPD.

By 2020, chronic obstructive pulmonary disease (COPD) will be the third cause of mortality. Extrapulmonary comorbidities influence the prognosis of patients with COPD. Tobacco smoking is a common risk factor for many comorbidities, including coronary heart disease, heart failure and lung cancer. Comorbidities such as pulmonary artery disease and malnutrition are directly caused by COPD, whereas others, such as systemic venous thromboembolism, anxiety, depression, osteoporosis, obesity, metabolic syndrome, diabetes, sleep disturbance and anaemia, have no evident physiopathological relationship with COPD. The common ground between most of these extrapulmonary manifestations is chronic systemic inflammation. All of these diseases potentiate the morbidity of COPD, leading to increased hospitalisations and healthcare costs. They can frequently cause death, independently of respiratory failure. Comorbidities make the management of COPD difficult and need to be evaluated and treated adequately.

Modulation of bleomycin-induced lung fibrosis by serotonin receptor antagonists in mice

Serotonin (5-hydroxytryptamine; 5-HT) is known to increase proliferation and collagen synthesis by fibroblasts. Two receptor subtypes, 5-HT2A and 5-HT2B, have been shown to play the most important roles in the lung. In the present study, the role of serotonin in lung fibrosis was investigated using the bleomycin mouse model. Serotonin concentrations in lung homogenates increased significantly over the time course of bleomycin-induced fibrosis, with a maximum at day seven. The expression of serotonin receptors 5-HT2A and 5-HT2B increased in the lung after bleomycin treatment, as assessed by PCR, specific binding and immunohistochemistry. Blockage of 5-HT2A receptors by ketanserin and 5-HT2B receptors by SB215505 reduced bleomycin-induced lung fibrosis, as demonstrated by reduced lung collagen content and reduced procollagen 1 and procollagen 3 mRNA expression. Serotonin antagonists promoted an antifibrotic environment by decreasing the lung mRNA levels of transforming growth factor-β1, connective growth factor and plasminogen activator inhibitor-1 mRNA, but had minimal effects on lung inflammation as assessed by bronchoalveolar lavage cytology analysis. Interestingly, the 5-HT2B receptor was strongly expressed by fibroblasts in the fibroblastic foci in human idiopathic pulmonary fibrosis samples. In conclusion, the present study showed involvement of serotonin in the pathophysiology of bleomycin-induced lung fibrosis in mice and identified it as a potential therapeutic target in lung fibrotic disorders.

Myosin molecular motor dysfunction in dystrophic mouse diaphragm.

Cross-bridge properties and myosin heavy chain (MHC) composition were investigated in isolated diaphragm from 6-mo-old control ( n = 12) and mdx( n = 12) mice. Compared with control, peak tetanic tension fell by 50% in mdx mice ( P < 0.001). The total number of cross bridges per square millimeter (×109), the elementary force per cross bridge, and the peak mechanical efficiency were lower in mdx than in control mice (each P < 0.001). The duration of the cycle and the rate constant for cross-bridge detachment were significantly lower in mdx than in control mice. In the overall population, there was a linear relationship between peak tetanic tension and either total number of cross bridges per square millimeter or elementary force per cross bridge ( r = 0.996 and r = 0.667, respectively, each P < 0.001). The mdx mice presented a higher proportion of type IIA MHC ( P < 0.001) than control mice and a reduction in type IIX MHC ( P < 0.001) and slow myosin isoforms ( P < 0.01) compared with control mice. We concluded that, in mdx mice, impaired diaphragm strength was associated with qualitative and quantitative changes in myosin molecular motors. It is proposed that reduced force generated per cross bridge contributed to diaphragm weakness in mdx mice.Cross-bridge properties and myosin heavy chain (MHC) composition were investigated in isolated diaphragm from 6-mo-old control (n = 12) and mdx (n = 12) mice. Compared with control, peak tetanic tension fell by 50% in mdx mice (P < 0.001). The total number of cross bridges per square millimeter (x10(9)), the elementary force per cross bridge, and the peak mechanical efficiency were lower in mdx than in control mice (each P < 0.001). The duration of the cycle and the rate constant for cross-bridge detachment were significantly lower in mdx than in control mice. In the overall population, there was a linear relationship between peak tetanic tension and either total number of cross bridges per square millimeter or elementary force per cross bridge (r = 0.996 and r = 0.667, respectively, each P < 0.001). The mdx mice presented a higher proportion of type IIA MHC (P < 0.001) than control mice and a reduction in type IIX MHC (P < 0.001) and slow myosin isoforms (P < 0.01) compared with control mice. We concluded that, in mdx mice, impaired diaphragm strength was associated with qualitative and quantitative changes in myosin molecular motors. It is proposed that reduced force generated per cross bridge contributed to diaphragm weakness in mdx mice.

Respiratory involvement in systemic lupus erythematosus

Respiratory involvement in systemic lupus erythematosus (SLE) is not as well-known as the cutaneous, rheumatological and renal manifestations. It occurs frequently but the diagnosis may be difficult because of the heterogeneity of the anatomical and clinical presentations. A precise diagnosis is crucial as new immunosuppressive drugs have considerably improved the prognosis. The pathology involves genetic, endocrine, environmental, pharmacological and immunological factors with a cytotoxic reaction of auto-antibodies against complement, a circulating immune complex reaction and a hyperactivity of B lymphocytes. Respiratory involvement in SLE can be classified in five groups based on the anatomy: pleural involvement, infiltrating pneumonia (lymphoid interstitial pneumonia, bronchiolitis obliterans with organizing pneumonia and acute lupus pneumonitis), airways involvement (upper airways, bronchi), vascular involvement (pulmonary hypertension, acute reversible hypoxaemia, alveolar haemorrhage, and antiphospholipid syndrome), muscular and diaphragmatic involvement (shrinking lung syndrome).Treatment is based, depending upon the type of involvement and its severity, on steroids which may be combined with immunosuppressants and plasmapherisis.

Diagnosis and management of idiopathic pulmonary fibrosis: French practical guidelines.

Idiopathic pulmonary fibrosis (IPF) is the most frequent chronic idiopathic interstitial pneumonia in adults. The management of rare diseases in France has been organised by a national plan for rare diseases, which endorsed a network of expert centres for rare diseases throughout France. This article is an overview of the executive summary of the French guidelines for the management of IPF, an initiative that emanated from the French National Reference Centre and the Network of Regional Competence Centres for Rare Lung Diseases. This review aims at providing pulmonologists with a document that: 1) combines the current available evidence; 2) reviews practical modalities of diagnosis and management of IPF; and 3) is adapted to everyday medical practice. The French practical guidelines result from the combined efforts of a coordination committee, a writing committee and a multidisciplinary review panel, following recommendations from the Haute Autorité de Santé. All recommendations included in this article received at least 90% agreement by the reviewing panel. Herein, we summarise the main conclusions and practical recommendations of the French guidelines.

Lung cancer in combined pulmonary fibrosis and emphysema: a series of 47 Western patients.

Introduction: The syndrome of combined pulmonary fibrosis and emphysema (CPFE) is characterized by imaging features consisting of the association of centrilobular and/or paraseptal emphysema and pulmonary fibrosis. Virtually all patients are smokers and thus at high risk of developing lung cancer. Methods: This retrospective multicentre study was conducted by the Groupe d’Etudes et de Recherche sur les Maladies “Orphelines” Pulmonaires (GERM”O”P). Results: A total of 47 patients presenting with lung cancer and CPFE syndrome were identified. All patients were smokers, with a mean of 47 pack-years. A pathological diagnosis of lung cancer was obtained for 38 (81%) patients. Histological type was squamous cell carcinoma in 17 (36%) patients, adenocarcinoma in 14 (30%), non–small-cell lung cancer not otherwise specified in three (6%), small-cell lung cancer in three (6%), and sarcomatoid carcinoma in one (2%). Overall, 20 of the 47 patients could not receive standard-of-care treatment for lung cancer, as per international recommendations or guidelines; this limitation was considered to be directly related to the CPFE syndrome in eight (40%) cases. Conclusion: Lung cancer in patients with CPFE syndrome represents a specific entity with a poor prognosis, that further represents the most characteristic and severe model of tobacco-related disease.

Revisiting the systemic vasculitis in eosinophilic granulomatosis with polyangiitis (Churg-Strauss) ☆: A study of 157 patients by the Groupe d'Etudes et de Recherche sur les Maladies Orphelines Pulmonaires and the European Respiratory Society Taskforce on eosinophilic granulomatosis with polyangiitis (Churg-Strauss)

OBJECTIVE To guide nosology and classification of patients with eosinophilic granulomatosis with polyangiitis (EGPA) based on phenotype and presence or absence of ANCA. METHODS Organ manifestations and ANCA status were retrospectively analyzed based on the presence or not of predefined definite vasculitis features or surrogates of vasculitis in patients asthma, eosinophilia, and at least one systemic organ manifestation attributable to systemic disease. RESULTS The study population included 157 patients (mean age 49.4±14.1), with a follow-up of 7.4±6.4years. Patients with ANCA (31%) more frequently had weight loss, myalgias, arthralgias, biopsy-proven vasculitis, glomerulonephritis on biopsy, hematuria, leukocytoclastic capillaritis and/or eosinophilic infiltration of arterial wall on biopsy, and other renal disease. A total of 41% of patients had definite vasculitis manifestations (37%) or strong surrogates of vasculitis (4%), of whom only 53% had ANCA. Mononeuritis multiplex was associated with systemic vasculitis (p=0.005) and with the presence of ANCA (p<0.001). Overall, 59% of patients had polyangiitis as defined by definite vasculitis, strong surrogate of vasculitis, mononeuritis multiplex, and/or ANCA with at least one systemic manifestation other than ENT or respiratory. Patients with polyangiitis had more systemic manifestations including arthralgias (p=0.02) and renal disease (p=0.024), had higher peripheral eosinophilia (p=0.027), and a trend towards less myocarditis (p=0.057). Using predefined criteria of vasculitis and surrogates of vasculitis, ANCA alone were found to be insufficient to categorise patients with vasculitis features. CONCLUSION We suggest a revised nomenclature and definition for EGPA and a new proposed entity referred to as hypereosinophilic asthma with systemic (non vasculitic) manifestations.

Activation of somatostatin receptors attenuates pulmonary fibrosis

Background and aim: Somatostatin analogues may have antifibrotic properties in the lung. The aim of this study was to evaluate the expression of the five somatostatin receptors sst1 to sst5 in normal and fibrotic mouse lung and the action of SOM230 (pasireotide), a new somatostatin analogue with a long half-life, in bleomycin induced lung fibrosis and in human lung fibroblasts in vitro. Methods: After intratracheal injection of bleomycin, C57Bl6 male mice received one daily subcutaneous injection of SOM230 or saline. The lungs were evaluated on days 3, 7 and 14 after administration of bleomycin. Results: We found that all somatostatin receptors were expressed in the normal mouse lung. The sst2 receptor mRNA expression was increased after bleomycin. SOM230 improved mice survival (69% vs 44%; p = 0.024), reduced lung collagen content at day 14 and decreased lung collagen-1 mRNA at day 7. SOM230 reduced bronchoalveolar lavage inflammatory cell influx at day 3, decreased lung connective tissue growth factor mRNA and transforming growth factor (TGF) β mRNA and increased lung hepatocyte growth factor and keratinocyte growth factor mRNA. The sst2 receptor was strongly expressed in the human lung (normal or fibrotic), particularly by fibroblasts. In vitro, SOM230 reduced BrdU incorporation by control human lung fibroblasts cultured under basal conditions or with TGFβ, and reduced alpha-1 collagen-1 mRNA expression in TGFβ stimulated fibroblasts. Conclusion: We conclude that SOM230 attenuates bleomycin induced pulmonary fibrosis in mice and human lung fibroblasts activation. This study points to a potential new approach for treating pulmonary fibrotic disorders.