Search

International audience; Background: Mineralogical analyses of bronchoalveolar lavage (BAL) may help in assessing past exposure to mineral particles. However, their interpretation relies on their quality, meaning their representativeness of the alveolar compartment. The aim of this study was to find predictive factors of BAL samples quality allowing a reliable mineralogical analysis. Methods: All BAL samples analyzed between 2018 and 2020 in the Asbestos Fibers and Particles Laboratory from Paris City were included. They were read by an experienced cyto-pathologist and validated according to their representativeness of the alveolar region compartment. Univariate and stratified analyses were conducted to identify factors associated with the samples’ cytological quality. Results: On the 780 samples included, 64.4% were deemed of good cytological quality and 17.9% were not interpretable. Injected volume and BAL yield (recovery volume on injected volume ratio) were associated with cytological quality. Injecting at least 100mL with a ≥60% yield or injecting at least 150mL with a ≥30% yield allowed having a good proportion of BAL with sufficient cytological quality. Conclusions: Injected volume greater than 100mL with sufficient BAL yield are essential factors to ensure a reliable mineralogical analysis of BAL samples.

Introduction Les pneumocytes de type 2 (p2) jouent un role cle dans les processus de regeneration apres des dommages alveolaires. Les mecanismes sous-jacents sont peu connus. L’objectif de ce travail est d’examiner si l’inhibiteur du cycle cellulaire p16INK4a module des proprietes des p2 et augmentant leurs capacites a induire une regeneration alveolaire. Methodes Des organoides pulmonaires ont ete realises par la mise en co-culture de cellules EpCAM+ obtenues par tri cellulaire magnetique (CD31-, CD45-, CD16/32-, CD90-, CD271-, Ter119-, EpCAM+) a partir de poumon de souris p16INK4a-/− ou WT avec des fibroblastes primaires pulmonaires WT. Une analyse de la taille et du nombre de colonies d’organoides formees (colony forming unit : CFU) et du type d’organoides (alveolaires ou bronchiques avec les marquages proSpC et acetylated tubulin-ACT) a ete realisee a 14 et 21 jours de culture. Dans un deuxieme temps, ces organoides ont ete obtenus a partir de poumon de souris emphysemateuses (J21 apres instillation d’elastase 2UI) compare a des souris controles (serum physiologique), p16INK4a-/− ou WT. Des analyses morphometriques (mean linear intercept) et le nombre de p2 ont ete realises 21 et 90 jours apres elastase. Resultats Les organoides formes de cellule EpCAM- p16INK4a-/− avaient une taille plus importante que ceux forme a partir d’EpCAM-WT a J14 (p = 0,046) et J21 (p = 0,0001). La majorite des organoides etaient alveolaires. La taille des organoides issus de souris emphysemateuses etait plus basse par rapport aux controles (p = 0,019), avec une tendance a la diminution du nombre de CFU. Les organoides issus de souris emphysemateuses p16INK4a-/− etaient de taille plus importante et plus nombreux que ceux issus de souris emphysemateuses WT. In vivo, la deletion de p16 etait associee 21 jours apres instillation d’elastase a un nombre plus important de p2 dans le poumon sans impact sur l’emphyseme. 90 jours apres elastase, les souris p16INK4a-/− avaient moins d’emphyseme (mean linear intercept) que les souris WT. Conclusions Inhiber p16INK4a augmente les capacites de regeneration endogene alveolaire des p2. Les mecanismes impliques restent a determiner.

International audience; Rationale: Promoting endogenous pulmonary regeneration is crucial after damage to restore normal lungs and prevent the onset of chronic adult lung diseases.Objectives: To investigate whether the cell-cycle inhibitor p16INK4a limits lung regeneration after newborn bronchopulmonary dysplasia (BPD), a condition characterized by the arrest of alveolar development, leading to adult sequelae.Methods: We exposed p16INK4a-/- and p16INK4a ATTAC (apoptosis through targeted activation of caspase 8) transgenic mice to postnatal hyperoxia, followed by pneumonectomy of the p16INK4a-/- mice. We measured p16INK4a in blood mononuclear cells of preterm newborns, 7- to 15-year-old survivors of BPD, and the lungs of patients with BPD.Measurements and Main Results: p16INK4a concentrations increased in lung fibroblasts after hyperoxia-induced BPD in mice and persisted into adulthood. p16INK4a deficiency did not protect against hyperoxic lesions in newborn pups but promoted restoration of the lung architecture by adulthood. Curative clearance of p16INK4a-positive cells once hyperoxic lung lesions were established restored normal lungs by adulthood. p16INK4a deficiency increased neutral lipid synthesis and promoted lipofibroblast and alveolar type 2 (AT2) cell development within the stem-cell niche. Besides, lipofibroblasts support self-renewal of AT2 cells into alveolospheres. Induction with a PPARγ (peroxisome proliferator-activated receptor γ) agonist after hyperoxia also increased lipofibroblast and AT2 cell numbers and restored alveolar architecture in hyperoxia-exposed mice. After pneumonectomy, p16INK4a deficiency again led to an increase in lipofibroblast and AT2 cell numbers in the contralateral lung. Finally, we observed p16INK4a mRNA overexpression in the blood and lungs of preterm newborns, which persisted in the blood of older survivors of BPD.Conclusions: These data demonstrate the potential of targeting p16INK4a and promoting lipofibroblast development to stimulate alveolar regeneration from childhood to adulthood.

Chronic obstructive pulmonary disease, a disease of increasing incidence, is related mainly to smoking. Although symptoms only appear at adulthood, the disease can develop from early life events. For example, bronchopulmonary dysplasia, which occurs in preterm infants, is characterized by airspace enlargement and could lead to late lung consequences. Once the lesions are established, no curative treatment is available. Stimulating lung regeneration from endogenous stem cells is therefore an exciting research domain, particularly through the activation of the mesenchymal contingent located in the lung stem cell niche., La bronchopneumopathie chronique obstructive, affection d’incidence croissante, est liée principalement au tabagisme. Bien que les symptômes n’apparaissent qu’à l’âge adulte, la maladie peut se développer à partir d’événements précoces de la vie. La dysplasie bronchopulmonaire, par exemple, survenant chez le nouveau-né prématuré, est caractérisée par un élargissement des espaces aériens et peut avoir des conséquences pulmonaires tardives. Une fois les lésions établies, aucun traitement curatif n’est disponible. Stimuler la régénération pulmonaire à partir de cellules souches endogènes est donc une perspective de recherche séduisante, notamment par le biais de l’activation du contingent mésenchymateux présent dans la niche des cellules souches pulmonaires.

The transcription factor p53 is overexpressed in the lung of patients with emphysema, but it remains unclear if it has a deleterious or protective effect in disease progression. We investigated the role of p53 in the elastase-induced emphysema model and the molecular underlining mechanisms. Wild-type (WT) and p53(-/-) mice were instilled with pancreatic porcine elastase. We quantified emphysema (morphometric analysis), chemokine (C-C motif) ligand 2 (CCL2), and TNF-α in bronchoalveolar lavage (BAL) (ELISA), oxidative stress markers [heme oxygenase 1 (HO1), NAD(P)H dehydrogenase quinone 1 (NQO1), and quantitative RT-PCR], matrix metalloproteinase 12 (MMP12) expression, and macrophage apoptosis (cleaved caspase-3, immunofluorescence). p53 gene expression was up-regulated in the lung of elastase-instilled mice. p53 deletion aggravated elastase-induced emphysema severity, pulmonary inflammation (macrophage and neutrophil numbers and CCL2 and TNF-α levels in BAL), and lung oxidative stress. These findings, except for the increase in CCL2, were reproduced in WT mice transplanted with p53(-/-) bone marrow cells. The increased number of macrophages in p53(-/-) mice was not a consequence of reduced apoptosis or an excess of chemotaxis toward CCL2. Macrophage expression of MMP12 was higher in p53(-/-) mice compared with WT mice after elastase instillation. These findings provide evidence that p53(-/-) mice and WT mice grafted with p53(-/-) bone marrow cells are more prone to developing elastase-induced emphysema, supporting a protective role of p53, and more precisely p53 expressed in macrophages, against emphysema development. The pivotal role played by macrophages in this phenomenon may involve the MMP12-TNF-α pathway.

Telomere shortening is associated with COPD and impaired lung function in cross-sectional studies, but there is no longitudinal study. We used data from 448 participants recruited as part of the French follow-up of the European Community Respiratory Health Survey. We found no relationship between telomere length at baseline and FEV1 decline after 11 years of follow-up. However, heavy smoking was associated with an accelerated FEV1 decline in individuals with short telomeres, but not in subjects with longer telomeres (p for interaction p=0.08). Our findings suggest that short telomere length in peripheral leucocytes might be a marker for increased susceptibility to the effect of smoking.

Introduction La bronchopneumopathie chronique obstructive represente la 4e cause de mortalite dans le monde et ne dispose a ce jour d’aucun traitement curatif. L’emphyseme, qui en est une des composantes, resulte de la destruction progressive des septums inter-alveolaires, conduisant a une insuffisance respiratoire. Parmi les marqueurs de senescence, des etudes montrent une surexpression du suppresseur de tumeurs p16 Ink4a dans les poumons de patients ayant un emphyseme compare aux fumeurs ou non-fumeurs sains. D’autres etudes ont montre l’influence de p16 Ink4a sur l’adipogenese. L’objectif est de determiner si la deletion de p16 Ink4a previent le developpement d’un emphyseme pulmonaire induit par une instillation d’elastase a un temps precoce ou tardif ainsi que les mecanismes impliques, en particulier l’induction de la lipogenese et l’activation des lipofibroblastes. Methodes Des souris adultes p16 Ink4a ko et sauvages (WT) ont recu une instillation intratracheale de 2UI d’elastase porcine pancreatique. Les souris ont ete sacrifiees 21 jours ou 90 jours apres l’instillation pour quantification morphometrique de l’emphyseme, evaluation de la septation secondaire et analyse de l’expression des genes de l’adipogenese et des marqueurs de pneumocytes. Evaluation dans un second temps des remaniements de la matrice extracellulaire. Resultats A 21 jours, la deletion de p16 Ink4a n’influence pas le degre d’emphyseme mais entraine une proliferation des pneumocytes de types 2, atteste par qPCR ou immunohistochimie ainsi qu’une activation de la lipogenese par rapport aux souris WT. A 90 jours, les souris p16 Ink4a presentaient un emphyseme significativement moins severe, des marqueurs de proliferation de pneumocytes 2 mais pas d’activation de l’adipogenese. A ce temps tardif, apparaissaient chez les souris p16 Ink4a des remaniements fibrotiques. Conclusion La deletion de p16 Ink4a ne protege pas de l’emphyseme induit par l’elastase dans un premier temps mais est associee a une amelioration des lesions a un temps tardif. Cet effet sous-tend un processus de regeneration alveolaire avec un remaniement secondaire la matrice extracellulaire.

The biological mechanisms of aging, and more specifically cellular senescence, are increasingly a subject of research. Cellular senescence may be a common determinant of many age-related diseases, including some chronic lung diseases such as chronic obstructive pulmonary disease (COPD) or idiopathic pulmonary fibrosis. Many arguments suggest that these diseases are associated with premature senescence of lung cells, which may be involved in the pathophysiology of respiratory alterations. Furthermore, these diseases are associated with systemic manifestations, such as bone loss, muscle wasting and atherosclerosis, which impact on symptoms and prognosis. Whether these alterations are related to a common pathogenic mechanism or develop independently in patients with COPD remains an open question. In this review, we will focus on cellular senescence and COPD. Two concepts will be discussed: (1) the role of cell senescence in the pathophysiology of lung destruction, vascular remodeling and inflammation in COPD, (2) the possible link between the pulmonary and systemic manifestations of COPD which could reflect a general process of accelerated aging.

International audience; Exposure to titanium dioxide (TiO2) nanoparticles (NPs) is associated with lung remodeling, but the underlying mechanisms are unknown. Matrix metalloprotease (MMP)-1 is an important actor in matrix homeostasis and could therefore participate in TiO2 NP effects. Our aim was to evaluate the effects of TiO2 NPs on MMP-1 expression and activity in lung pulmonary fibroblasts and to understand the underlying mechanisms and assess the importance of the physicochemical characteristics of the particles in these effects. Human pulmonary fibroblasts (MRC-5 cell line and primary cells) were exposed to 10 or 100 μg/cm(2) TiO2 (two anatases, two anatase/rutile mix, one rutile NP, and one micrometric) and carbon black (CB) NPs for 6 to 48 hours. We examined cell viability, MMP-1 expression and activity, and the implication of oxidative stress, transforming growth factor (TGF)-β, extracellular MMP inducer, and IL-1β in MMP-1 expression. All TiO2 NPs induced MMP-1 (mRNA and protein expression), repression of procollagen-1, and α-actin expression, but only the two anatase/rutile mix induced MMP-1 activity. Micrometric TiO2 had smaller effects than TiO2 NPs, and CB NPs did not induce MMP-1. MMP-1 induction by TiO2 NPs was not related to TGF-β, oxidative stress, or EMPRIN expression but was related to IL-1β expression, which partly drives MMP-1 induction by two TiO2 NPs (one anatase/rutile mix and the rutile one). Taken together, our results show that TiO2 NPs are potent inducers and regulators of MMP-1 expression and activity, partly via an IL-1β-dependent mechanism. This may explain TiO2 lung remodeling effects.

International audience; Rationale: Sleep disorders may lead to stress-induced premature aging and telomere shortening.Objectives: To determine whether obstructive sleep apnea syndrome causing intermittent hypoxemic episodes was associated with telomere shortening independently from the comorbidities associated with this syndrome.Methods: We conducted a cross-sectional study in 161prospectivelly enrolled, untreated, middle-aged men free of known comorbidities related or unrelated to sleep apnea. Each participant underwent full standard overnight polysomnography. Patients with apnea sleep syndrome were naive to treatment.Measurements and main results: In univariate analysis, we found that telomere shortening was associated with older age, apnea-hypopnea index, oxygen desaturation index, waist circumference, and fat mass. After adjustment for age, only apnea-hypopnea index and oxygen desaturation index were significantly related to telomere shortening. The mean telomere length ratio was 0.70 ± 0.37 in the participants without sleep apnea, compared with 0.61 ± 0.22 and 0.53 ± 0.16 in those with mild to moderate and severe sleep apnea, respectively (P = 0.01). In multivariate analysis, we found that oxygen desaturation index was the only factor independently associated with telomere length. Arterial stiffness assessed by carotid-femoral pulse wave velocity correlated negatively with telomere length.Conclusions: Intermittent hypoxemia due to obstructive sleep apnea syndrome is a major contributor to telomere shortening in middle-aged men. Oxidative stress may explain this finding.

Introduction La dysplasie bronchopulmonaire (DBP), caracterisee par un arret de l’alveolisation, se developpe chez les prematures et entraine des consequences pulmonaires durables. Le facteur de transcription p16Ink4 est implique dans le cycle cellulaire et son expression est augmentee dans les cellules progenitrices leucocytaires du sang de cordon des nouveau-nes prematures. Objectifs Determiner dans un modele murin de BPD, si la deletion de p16 favorise la regeneration pulmonaire chez les souris nouveau-nees, et protege contre les consequences pulmonaires a l’âge adulte. Methodes Des souris sauvages et p16−/− ont ete exposees a l’hyperoxie (85 % FiO2) ou a l’air ambiant du jour (j) 3 a 14. Les mesures suivantes ont ete realisees a j14, 16 et 60 et 120 : morphometrie, elastine (Weigert), collagene (rouge sirius), identification des lipofibroblastes (IHC : ADRP, lipidtox), etudes transcriptomique et lipidomique, voies du metabolisme lipidique LXR (par q PCR : SREBP, SCAP, ADRP). Puis des souris sauvages ont ete traitees quotidiennement a partir de j14 apres l’hyperoxie, par un activateur de la voie LXR, T0901317, ou la rosiglitazone activateur de PPARg. Resultats A j14, l’hyperoxie a provoque un arret de l’alveolisation et une augmentation des marqueurs de senescence et d’inflammation (avec polarisation des macrophages en M1). Les souris hyperoxiques p16−/− ne sont pas protegees contre cette hypoalveolarisation mais presentent moins d’inflammation (avec switch des macrophages de M1 a M2) par rapport aux souris sauvages. A l’âge adulte, la deletion de p16 permet une restauration de l’architecture pulmonaire, associee a une augmentation du nombre de lipofibroblastes (ADRP, lipidtox en IHC) et du metabolisme lipidique (expressions augmentees de SREBP, ADRP en qPCR, contenu augmente en lipides neutres). De la meme maniere, l’administration la rosiglitazone, et T0901317, a permis d’ameliorer significativement l’architecture pulmonaire. Conclusion La deletion de p16 limite les sequelles parenchymateuses de la DBP a l’âge adulte, via l’induction des lipofibroblastes, secondaire a l’activation de la voie LXR favorisant ainsi les processus de regeneration pulmonaire. L’activation de la voie LXR induit les memes benefices et pourrait ouvrir des perspectives therapeutiques dans la prise en charge de la DBP.

Les nanotechnologies sont definies comme l’ensemble des techniques visant a concevoir, caracteriser et produire des materiaux a l’echelle du nanometre dans au moins une de leurs dimensions. Ces nanomateriaux sont eux-memes constitues de nano-objets (nanoparticules, nanotubes…). Leur dimension nanometrique leur confere, du fait des lois de la physique quantique, de nouvelles proprietes physicochimiques et des comportements inedits. Les applications des nanotechnologies sont multiples (cosmetologie, industrie, medecine…). La production et l’utilisation des nanomateriaux connaissent une croissance importante. Cependant, des inquietudes sont emises sur les effets potentiels des nanoparticules sur la sante, a court et a long terme. Ces questions sont motivees par la connaissance des effets toxiques sur la sante des particules micrometriques de la pollution atmospherique et par la crainte de voir ces effets s’amplifier du fait de la nanodimension de ces materiaux. Dans cet article, est proposee une synthese globale mais non exhaustive des connaissances actuelles concernant la penetration, la deposition, la translocation et l’elimination dans l’appareil respiratoire, ainsi que les effets respiratoires des nanoparticules metalliques (plus particulierement du dioxyde de titane) et des nanotubes de carbone. L’ensemble des etudes experimentales in vivo et in vitro actuellement disponibles met en evidence l’existence d’effets biologiques des nanoparticules sur l’appareil respiratoire avec, notamment, la generation de stress oxydant, un effet pro-inflammatoire, un effet prothrombotique, la possibilite de survenue de fibrose et d’emphyseme pulmonaire ou de dommages a l’ADN. Une meilleure connaissance des effets biologiques potentiels des nanoparticules est requise, afin de mettre en place des mesures de prevention appropriees en milieu de travail et/ou en population generale, si cela s’averait necessaire.

Telomere length is considered a marker for biological aging. Chronic obstructive pulmonary disease (COPD) may be associated with premature aging.To test the hypothesis that patients with COPD experience accelerated telomere shortening and that inflammation is linked to this process.We measured telomere length, using a quantitative polymerase chain reaction-based method, and plasma levels of various cytokines in 136 patients with COPD, 113 age- and sex-matched smokers, and 42 nonsmokers with normal lung function.Median (range) telomere length ratio was significantly lower in patients with COPD (0.57 [0.23-1.18]) than in control smokers (0.79 [0.34-1.58]) or nonsmokers (0.85 [0.38-1.55]) (P0.001). The difference remained highly significant when using logistic regression analysis adjusted for age, sex, and tobacco exposure. Both females and males with COPD had shorter telomere length than same-sex control subjects. Telomere length was related to age in patients and control subjects but was shorter in patients than in control subjects in all age groups. No relationship was found between telomere length and tobacco exposure in patients or control subjects, with no difference between control smokers and nonsmokers. In patients with COPD, telomere length was related to PaO2 (P0.001) and PaCO2 (P0.001) but not to lung function parameters or the BODE Index. Patients with COPD also had elevated plasma levels of various cytokines, interleukin-6 correlating negatively with telomere length (P0.001).Given that in vivo telomere length reflects cellular turnover and exposure to oxidative and inflammatory damage, our data support accelerated aging in COPD.

Introduction Le deficit en alpha-1 antitrypsine est associe a un risque accru d’emphyseme pulmonaire. L’objectif de cette etude est de decrire les caracteristiques des patients emphysemateux deficitaires. Methodes Etude de cohorte prospective multicentrique. Criteres d’inclusion : patients adultes, presentant un emphyseme identifie au scanner, deficitaires en alpha-1 antitrypsine et suivis en France. Les caracteristiques cliniques, fonctionnelles, la qualite de vie et les modalites therapeutiques sont recueillies tous les 6 mois pendant 5 ans. Resultats Deux cent un patients ont ete recenses par 56 centres entre 2005 et 2008. Les caracteristiques a l’inclusion des 110 premiers patients ont ete analysees. L’âge moyen etait de 50 ans (DS : 11,8), 62,7 % etaient des hommes, 90 % etaient fumeurs. Caracteristiques fonctionnelles (% theo.) : VEMS : 42,8 (19,6), CPT : 128,3 (21,7), CRF : 167,0 (46,0), test de marche de 6 minutes (metres) : 413 (130). 51 (46,4 %) patients recevaient un traitement substitutif ; le mode d’administration etait hebdomadaire (37,5 %), bimensuel (35,4 %) ou mensuel (25,5 %). Le seul facteur associe a la probabilite d’etre traite etait le centre de suivi du patient. Conclusion Cette etude revele les grandes disparites de presentation clinique et de prise en charge des patients emphysemateux deficitaires en alpha-1 antitrypsine et souligne la necessite d’une homogeneisation des pratiques.

Background: Oxidative stress, resulting from the increased oxidative burden and decreased level of antioxidant proteins, plays a role in the pathophysiology of smoking-related pulmonary emphysema. Expression of several antioxidant proteins, such as heme oxygenase-1 (HO-1), glutathione peroxidase 2 (GPX2) and NAD(P)H:quinone oxidoreductase 1 (NQO1), results from an equilibrium created by positive or negative regulation by the transcription factors Nrf2, Keap1 and Bach1, respectively. However, whether the expression of these transcription factors is altered in emphysema and could account for decreased expression of antioxidant proteins is not known. A study was undertaken to investigate the expression and subcellular localisation of Nrf2, Keap1 and Bach1 as potential regulators of HO-1, GPX2 and NQO1 in alveolar macrophages, a key cell in oxidative stress, in lung surgical specimens from non-smokers without emphysema and smokers with and without emphysema. Methods and results: Western blot, immunohistochemical and laser scanning confocal analysis revealed that the Nrf2 protein level decreased significantly in whole lung tissue and alveolar macrophages (cytosol and nucleus) in patients with emphysema compared with those without emphysema. Conversely, Bach1 and Keap1 levels were increased in patients with emphysema. These modifications were associated with a parallel decrease in the expression of HO-1, GPX2 and NQO1 at the cellular level, which was inversely correlated with airway obstruction and distension indexes, and increased macrophage expression of the lipid peroxidation product 4-hydroxy-2-nonenal. Silencing RNA experiments in vitro in THP-1 cells were performed to confirm the cause-effect relation between the loss of Nrf2 and the decrease in HO-1, NQO1 and GPX2 expression. Nrf2/Keap1-Bach1 equilibrium was altered in alveolar macrophages in pulmonary emphysema, which points to a decreased stress response phenotype. Conclusions: This finding opens a new view of the pathophysiology of emphysema and could provide the basis for new therapeutic approaches based on preservation and/or restoration of such equilibrium.

Due to several commercial applications of manufactured nanoparticles (NPs), such as silver (Ag NPs), titanium dioxide (TiO2 NPs) and cerium dioxide (CeO2 NPs), knowledge of the toxicity of those NPs is of great importance. Many studies have linked exposure to fine and ultrafine particles (from air pollution) to an increase of morbidity or mortality due to various respiratory or cardiovascular diseases. Several works have focused on the effects of pulmonary exposure to manufactured NPs. It has been shown that exposure to NPs may lead to an inflammatory response, pulmonary fibrosis and emphysema. However, less is known on the effect of exposure to NPs on the offspring. It has been reported that exposure during pregnancy to TiO2 NPs and SiO2 NPs is associated with fetal hypertrophy, neurotoxicity, and exposure to carbon black NPs induced renal disease in the offspring. NPs may interfere with normal fetal lung development. In addition, a recent study reported that pulmonary exposure of newborn mice to TiO2 NPs was associated with pulmonary inflammation and impaired lung development. Therefore, the aim of this study is to assess the impact of exposure by the respiratory route to various NP during pregnancy on lung development of the offspring in a mouse model, and to determine the key parameters involved in lung alterations. For this study, we used three metal NPs: TiO2, Ag, and CeO2 with the same size and shape, to assess the impact of NPs physico-chemical properties in the potential effects on lung development. C57Bl6/J pregnant mice were exposed weekly to 100 μg NPs by nonsurgical intratracheal instillation. Analysis (biological, histological and functional) of the lungs of the offspring were made at different time of lung development: one day before delivery (18GD for gestational day), 14 days after birth (pulmonary alveolization) and 21 days after birth (lung maturity). Preliminary results show that the exposure to TiO2 NPs during pregnancy did not affect the number of fetuses per litter, or the weight of uterus and placenta. However, the weight of fetuses whose mothers were exposed to TiO2 NPs is significantly decreased. A decrease of VEGF-A gene expression, involved in lung development, was also observed at 18GD. These preliminary results suggest that exposure to TiO2 NPs during pregnancy could affect the development of the offspring. For the remainder of this work, pregnant mice will be exposed to other NPs (Ag and CeO2) in order to see if this effect depends on the type of NP. Moreover additional analyzes will be performed to confirm whether lung alterations are observed at later times after birth, and to understand the key parameters and mechanism associated with these changes.

Chronic exposure to particulate air pollution is associated with lung function impairment. To determine the molecular mechanism(s) of this phenomenon, we investigated, in an alveolar human epithelial cell line (A549), whether diesel exhaust particles (DEPs), a main component of particulate air pollution, modulates the expression and activity of the matrix metalloprotease (MMP)-1, a collagenase involved in alveolar wall degradation. Interaction of DEPs with cigarette smoke, which also produces structural and functional lung alterations, was also investigated. A noncytotoxic concentration of DEPs induced an increase in MMP-1 mRNA and protein expression and activity in A549 cells without modifying the expression of the MMP inhibitors TIMP-1 and -2. This effect was not potentiated when cells were coexposed to noncytotoxic concentrations of cigarette smoke condensate. DEP-induced MMP-1 was associated with increased ERK 1/2 phosphorylation and upregulation of expression and activity of the NADPH oxidase analog NOX4. Cell transfection with a NOX4 small interfering RNA prevented these phenomena, showing the critical role of a NOX4 ERK 1/2 pathway in DEP-induced MMP-1 expression and activity. Similar results to those observed in A549 cells were obtained in another human lung epithelial cell line, NCI-H292. Furthermore, experiments in mice intratracheally instilled with DEPs confirmed the in vitro findings, showing the induction of NOX4 and MMP-1 protein expression in alveolar epithelial cells. We conclude that alveolar alterations secondary to MMP-1 induction could explain lung function impairment associated with exposure to particulate pollution.

Heme oxygenase (HO), the heme-degrading enzyme, has shown anti-inflammatory effects in several models of pulmonary diseases. HO is induced in airways during asthma; however, its functional role is unclear. Therefore, we evaluated the role of HO on airway inflammation [evaluated by bronchoalveolar lavage (BAL) cellularity and BAL levels of eotaxin, PGE2, and proteins], mucus secretion (evaluated by analysis of MUC5AC gene expression and periodic acid-Schiff staining), oxidative stress (evaluated by quantification of 4-hydroxynonenal adducts and carbonylated protein levels in lung homogenates), and airway responsiveness to histamine in ovalbumin (OVA)-sensitized and multiple aerosol OVA or saline-challenged guinea pigs (6 challenges, once daily, OVA group and control group, respectively). Airway inflammation, mucus secretion, oxidative stress, and responsiveness were significantly increased in the OVA group compared with the control group. HO upregulation by repeated administrations of hemin (50 mg/kg ip) significantly decreased airway responsiveness in control animals and airway inflammation, mucus secretion, oxidative stress, and responsiveness in OVA animals. These effects were reversed by the concomitant administration of the HO inhibitor tin protoporphyrin-IX (50 μmol/kg ip). Repeated administrations of tin protoporphyrin-IX alone significantly increased airway responsiveness in control animals but did not modify airway inflammation, mucus secretion, oxidative stress, and responsiveness in OVA animals. These results suggest that upregulation of the HO pathway has a significant protective effect against airway inflammation, mucus hypersecretion, oxidative stress, and hyperresponsiveness in a model of allergic asthma in guinea pigs.

International audience; The development and the increasing production of manufactured nanoparticles (NP) are raising safety concerns because of the potential effects of NP on human health, particularly at the respiratory level. Several studies have shown that exposure to manufactured NP can induce pathogenic biological effects, with lung remodelling (fibrosis, emphysema…), depending on the physicochemical characteristics of the NP. Currently, oxidative stress and inflammation are the most widely accepted paradigms of NP toxicity; however, the exact underlying mechanisms in the biological effects of NP still remain unknown. Autophagy is a physiological process that allows the autodigestion of the subcellar components and which is also involved in the elimination of intracellular pathogens. It has been shown that this process can negatively regulate inflammation and oxidative stress. Thus, the hypothesis of this study is that a defective autophagy could be a new mechanism explaining, at least in part, NP effects. We choose to focus on TiO2 NP since it is one of the most abundantly produced and widely used NP. We used seven TiO2 NPs presenting different physicochemicals properties (size, crystal phase, surface embedding) and compared their effects to those of micron-size TiO2 and carbon black (CB - for chemical composition effects). NPs were characterized by electron microscopy, dynamic light scattering and X-ray diffraction. Murine macrophages (RAW cell line) were exposed to 50 μg/mL TiO2 and CB NP for 6 hours. Effects of NP on the autophagy process were analysed by looking at the expression of autophagy markers (LC3-II and p62) and lysosomal proteins (LAMPs and cathepsins). We also analysed the cytoskeleton network by fluorescence microscopy. Moreover, expression of inflammatory cytokines was determined in macrophages exposed to NP. All particles, except the micrometric one, induced an increase of LC3-II protein expression, indicating an accumulation of autophagosomes. These particles also increased p62 protein level, suggesting an autophagy blockade. This perturbation of the autophagy process by NP does not seem to result from a disruption of the cytoskeleton but from a defect in the lysosome function as suggested by a decrease of mature cathepsins expression. Moreover, preliminary results showed that exposure to TiO2 NP induce inflammation, at different levels depending on their physicochemicals characteristics. These results suggest that some TiO2 NP, depending on their physicochemical properties, can block the autophagy process. The future work will be to understand the mechanisms explaining this autophagy dysfunction and to determine its consequence on the toxicity induced by these NP.

Reactive oxygen species (ROS) increase the contractile response of airway smooth muscle (ASM). Heme oxygenase (HO) catabolizes heme to the powerful antioxidant bilirubin. Because HO is expressed in the airways, we investigated its effects on ASM contractility and ROS production in guinea pig trachea. HO expression was higher in the epithelium than in tracheal smooth muscle. Incubation of tracheal rings (TR) with the HO inhibitor tin protoporphyrin (SnPP IX) or the HO substrate hemin increased and decreased, respectively, ASM contractile response to carbamylcholine. The effect of hemin was reversed by SnPP and mimicked by the antioxidants superoxide dismutase (SOD) and catalase. Hemin significantly reduced the effect of carbamylcholine in rings treated with the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ), compared with ODQ-treated rings without hemin incubation, suggesting that the CO-guanosine 3′,5′-cyclic monophosphate pathway was not involved in the control of tracheal reactivity. SnPP and hemin increased and decreased ROS production by TR by 18 and 38%, respectively. Bilirubin (100 pM) significantly decreased TR contractility and ROS production. Hemin, bilirubin, and SOD/catalase decreased phosphorylation of the contractile protein myosin light chain, whereas SnPP significantly augmented it. These data suggest that modulation of the redox status by HO and, moreover, by bilirubin modulates ASM contractility by modulating levels of phosphorylated myosin light chain.

Skeletal muscle failure is a frequent manifestation of sepsis that affects prognosis and rehabilitation by impairing respiration and ambulation. Animal studies have shown that the inducible NO synthase (NOS2) is expressed in skeletal muscles during sepsis, likely affecting muscular function, by promoting the formation of the strong oxidant peroxynitrite. In contrast, whether human skeletal muscle expresses a functional NOS2 in similar conditions is unknown. We studied NOS2 expression (mRNA and protein) and activity and its role in contractile function in samples from rectus abdominis muscle obtained during surgical procedure in 16 septic patients and in 21 controls. Peroxynitrite formation was detected by immunohistochemical detection of nitrotyrosine residues. The main results of this study are as follows: (1) A significant increase in NOS2 mRNA, protein, and activity was found in muscles from septic patients, the expression of NOS2 protein positively correlating with sepsis severity. (2) Contractile force was significantly lower in septic than in control muscles. This phenomenon was not reverted by muscle incubation ex vivo with the NOS inhibitor L-NMMA, indicating that NO was not involved in force reduction at the time of biopsy. (3) NOS2 expression in skeletal myocytes was strongly co-localized with nitrotyrosine, revealing muscular peroxynitrite generation during the septic process, before the muscle was biopsied. Exposure of control muscles to an amount of peroxynitrite similar to that generated in septic muscles during the septic process resulted in a nonreversible reduction in force generation. These results suggest that NOS2 could be involved in the decreased muscular force of septic patients via the local generation of peroxynitrite.

To evaluate the effect of systemic hypoxia on leukocyte-endothelium interactions in peripheral tissues, we studied by intravital microscopy leukocyte rolling velocity and adherence in venules of rat cremaster muscle. We examined the possible roles of changes in blood oxygenation, peripheral tissue oxygenation, changes in local shear rate, and the involvement of integrins. Six groups of rats submitted to either control normoxic conditions, or systemic hypoxia (PO2 = 51 mm Hg) associated with either low O2 tension of Krebs superfusing the muscle, high O2 tension of the Krebs superfusing the muscle, anti-lymphocyte function-associated antigen (LFA)-1beta antibody, pentoxifylline, or normoxic conditions associated with partial occlusion of the artery perfusing the muscle. We found that: (1) systemic moderate hypoxia resulting from purely respiratory disturbance even in the absence of local stop-flow phenomenon or circulatory shock can induce an increase in leukocyte adhesion and a decrease in leukocyte rolling velocity in the microcirculation of peripheral tissues; (2) to be present, this increase in leukocyte adhesion does not require tissue hypoxia of the peripheral tissue but the effect of systemic hypoxia on rolling velocity is prevented by tissue oxygenation; (3) this increase in leukocyte adhesion is mediated by CD11/CD18 integrins but is not due to changes in local shear rate.

Background Systemic hypotension may complicate the early postoperative period after lung transplantation. A release of proinflammatory cytokines secondary to lung ischemia/reperfusion injury could be involved in the pathogenesis of this early hemodynamic failure (EHF). Study objective To assess prospectively whether the occurrence of EHF is associated with a release of cytokines in the systemic circulation. Design Blood samples were taken daily during the first postoperative week in 26 patients who underwent a double or a single-lung transplantation. These patients were divided into three groups: 7 patients who experienced EHF and subsequently died (EHF group); 15 patients without EHF (control group); and 4 patients without EHF but with an identified sepsis (sepsis group). The serum levels of interleukin (IL)-1p, tumor necrosis factor-α (TNF-α), IL-6, and IL-8 were compared among the three groups. Results In the EHF group, the levels of each cytokine peaked at day 1 postoperatively. Cytokine levels at day 1 were significantly higher in the EHF group than in the control group (p Conclusion We conclude that EHF is associated with a massive release of proinflammatory cytokines that could play a determinant role in the pathogenesis of this complication.

The mucociliary system, consisting of mucus-secreting goblet cells and ciliated cells, generates a constant overturning layer of protective mucus that lines the airway epithelium. Mucus hypersecretion and the pathophysiological changes associated are hallmarks of many pulmonary diseases including asthma, chronic obstructive pulmonary disease, and cystic fibrosis. Excessive mucus production leads to airway obstruction and, because there is currently no effective treatment, contributes to morbidity and mortality of many patients. Goblet cell differentiation and mucus production are subject to extensive control. An emerging concept is that not all goblet cells are phenotypically identical suggesting that specific molecular pathways orchestrate mucin overproduction. This paper attempts to describe the cellular and molecular mechanisms governing the differentiation of goblet cells in pulmonary diseases, a prerequisite for the development of new therapeutic agents.

Introduction La dysplasie bronchopulmonaire (DBP) est une pathologie du nouveau-ne premature favorisee par une oxygenotherapie precoce et caracterisee par un developpement pulmonaire anormal avec elargissement des espaces aeriens. L’hypoalveolisation et le defaut de septation des saccules primitifs correspondent a un defaut de production d’elastine par les fibroblastes. Les pneumocytes 2 pourraient aussi jouer un role en se differenciant en pneumocytes 1 si ceux-ci sont alteres. Cependant, la physiopathologie de cette maladie reste mal connue. La senescence, dont p16Ink4a est un acteur cle, est un arret permanent de la proliferation limitant le renouvellement des tissus et pourrait etre impliquee dans ce processus par le biais d’un defaut de differenciation et/ou reparation. L’objectif de ce travail est de determiner le role causal de p16 et de la senescence cellulaire sur la DBP dans un modele murin. Methodes Des souriceaux sauvages et p16-/-, ont ete exposes a une FiO 2 a 85 %, dans une enceinte hermetique, pendant la periode d’alveolisation, de j3 apres la naissance a j14. La morphometrie (intercepte lineaire moyen, surface alveolaire), la quantite d’elastine et sa distribution (coloration de Weigert) ont ete evaluees. La senescence a ete quantifiee par mesure de l’activite beta-galactosidase sur poumon frais et par l’expression en qPCR sur poumon total de p21. La division cellulaire a ete mesuree par immunohistochimie (Ki67). L’expression de l’elastine et de marqueurs inflammatoire (IL6, IL1β) a ete evaluee par qPCR sur poumon total. Resultats Apres exposition a l’hyperoxie, les souriceaux presentaient (1) une diminution de la surface alveolaire, une augmentation de l’intercepte lineaire moyen, une diminution de la quantite d’elastine et du nombre de cretes d’elastine, semblables aux lesions de poumons dysplasiques, (2) des marqueurs de senescence augmentes (expression accrue de la beta-galactosidase et de l’ARNm de p21), (3) une inflammation (IL6 et Il1β en ARNm). Il n’existait pas de difference entre les souriceaux sauvages et p16-/- pour les parametres sus-cites. En revanche, les souriceaux p16-/- en hyperoxie, compares aux sauvages, presentaient une division cellulaire accrue (Ki67), au sein du parenchyme pulmonaire. Conclusion Le modele d’hyperoxie se caracterise par une hypoalveolisation et une senescence majoree, non modulees par p16. En revanche, la deletion de p16, via une division cellulaire accrue, pourrait permettre une meilleure reparation a l’âge adulte.

International audience; Rationale: Chronic obstructive pulmonary disease (COPD) is associated with lung fibroblast senescence, a process characterized by the irreversible loss of replicative capacity associated with the secretion of inflammatory mediators. However, the mechanisms of this phenomenon remain poorly defined.Objectives: The aim of this study was to analyze the role of prostaglandin E2 (PGE2), a prostaglandin known to be increased in COPD lung fibroblasts, in inducing senescence and related inflammation in vitro in lung fibroblasts and in vivo in mice.Methods: Fibroblasts were isolated from patients with COPD and from smoker and nonsmoker control subjects. Senescence markers and inflammatory mediators were investigated in fibroblasts and in mice.Measurements and main results: Lung fibroblasts from patients with COPD exhibited higher expression of PGE2 receptors EP2 and EP4 as compared with nonsmoker and smoker control subjects. Compared with both nonsmoker and smoker control subjects, during long-term culture, COPD fibroblasts displayed increased senescent markers (increased senescence associated-β galactosidase activity, p16, and p53 expression and lower proliferative capacity), and an increased PGE2, IL-6, IL-8, growth-regulated oncogene (GRO), CX3CL1, and matrix metalloproteinase-2 protein and cyclooxygenase-2 and mPGES-1 mRNA expression. Using in vitro pharmacologic approaches and in vivo experiments in wild-type and p53(-/-) mice we demonstrated that PGE2 produced by senescent COPD fibroblasts is responsible for the increased senescence and related inflammation. PGE2 acts either in a paracrine or autocrine fashion by a pathway involving EP2 and EP4 prostaglandin receptors, cyclooxygenase-2-dependent reactive oxygen species production and signaling, and consecutive p53 activation.Conclusions: PGE2 is a critical component of an amplifying and self-perpetuating circle inducing senescence and inflammation in COPD fibroblasts. Modulating the described PGE2 signaling pathway could provide a new basis to dampen senescence and senescence-associated inflammation in COPD.

Background Titanium dioxide (TiO2) and carbon black (CB) nanoparticles (NPs) have biological effects that could aggravate pulmonary emphysema. The aim of this study was to evaluate whether pulmonary administration of TiO2 or CB NPs in rats could induce and/or aggravate elastase-induced emphysema, and to investigate the underlying molecular mechanisms. Methods On day 1, Sprague-Dawley rats were intratracheally instilled with 25 U kg−1 pancreatic porcine elastase or saline. On day 7, they received an intratracheal instillation of TiO2 or CB (at 100 and 500 μg) dispersed in bovine serum albumin or bovine serum albumin alone. Animals were sacrificed at days 8 or 21, and bronchoalveolar lavage (BAL) cellularity, histological analysis of inflammation and emphysema, and lung mRNA expression of heme oxygenase-1 (HO-1), interleukin-1β (IL-1β), macrophage inflammatory protein-2, monocyte chemotactic protein-1, and matrix metalloprotease (MMP)-1, and -12 were measured. In addition, pulmonary MMP-12 expression was also analyzed at the protein level by immunohistochemistry. Results TiO2 NPs per se did not modify the parameters investigated, but CB NPs increased perivascular/peribronchial infiltration, and macrophage MMP-12 expression, without inducing emphysema. Elastase administration increased BAL cellularity, histological inflammation, HO-1, IL-1β and macrophage MMP-12 expression and induced emphysema. Exposure to TiO2 NPs did not modify pulmonary responses to elastase, but exposure to CB NPs aggravated elastase-induced histological inflammation without aggravating emphysema. Conclusions TiO2 and CB NPs did not aggravate elastase-induced emphysema. However, CB NPs induced histological inflammation and MMP-12 mRNA and protein expression in macrophages.

We measured in rats the effects of 48 h of mechanical ventilation on the weight, contractile properties, and enzymatic profile of the diaphragm, the soleus and the extensor digitorium longus (EDL) muscles. Eighteen animals were randomly divided into a mechanically ventilated (MV, n = 9) group or a control (C, n = 9) group. During the 48 h of mechanical ventilation, animals in the MV group were anesthetized with sodium thiopental and enterally fed with a gastric catheter. Group C animals were neither anesthetized nor mechanically ventilated during the 48-h experimental period, and they had access to food and water ad libitum. Muscular contractile properties were measured in vitro by analysis of force-frequency curves and twitch characteristics. The weights of the three muscles were significantly reduced in the MV group compared with those in the C group. This was accompanied in the diaphragm by a reduction in the normalized force generated for all the frequencies of stimulation, except 20 Hz, whereas twitch characteristics were not modified. The forces generated by the soleus and EDL were not significantly reduced in the MV group compared with those in the C group. Diaphragm, soleus, and EDL citrate synthase and lactate dehydrogenase activities were not significantly different in the two groups. We conclude that mechanical ventilation for 48 h in rats produces a selective force reduction in the diaphragm.

Chronic obstructive pulmonary disease (COPD) is associated with chronic inflammation of unknown pathogenesis.To investigate whether telomere dysfunction and senescence of pulmonary vascular endothelial cells (P-ECs) induce inflammation in COPD.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.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.Telomere dysfunction and premature P-EC senescence are major processes perpetuating lung inflammation in COPD.

Persistence of myofibroblasts is believed to contribute to the development of fibrosis in idiopathic pulmonary fibrosis (IPF). Transforming growth factor beta1 (TGFbeta1) irreversibly converts fibroblasts into pathological myofibroblasts, which express smooth muscle alpha-actin (alpha-SMA) and produce extracellular matrix proteins, such as procollagen I (alpha1). Reactive oxygen species produced by NADPH oxidases (NOXs) have been shown to regulate cell differentiation. It was hypothesised that NOX could be expressed in parenchymal pulmonary fibroblasts and could mediate TGFbeta1-stimulated conversion of fibroblasts into myofibroblasts.Fibroblasts were cultured from the lung of nine controls and eight patients with IPF. NOX4, alpha-SMA and procollagen I (alpha1) mRNA and protein expression, reactive oxygen species production and Smad2/3 phosphorylation were quantified, in the absence and in the presence of incubation with TGFbeta1. Migration of platelet-derived growth factor (PDGF)-induced fibroblasts was also assessed.It was found that (1) NOX4 mRNA and protein expression was upregulated in pulmonary fibroblasts from patients with IPF and correlated with mRNA expression of alpha-SMA and procollagen I (alpha1) mRNA; (2) TGFbeta1 upregulated NOX4, alpha-SMA and procollagen I (alpha1) expression in control and IPF fibroblasts; (3) the change in alpha-SMA and procollagen I (alpha1) expression in response to TGFbeta1 was inhibited by antioxidants and by a NOX4 small interfering RNA (siRNA); (4) NOX4 modulated alpha-SMA and procollagen I (alpha1) expression by controlling activation of Smad2/3; and (5) NOX4 modulated PDGF-induced fibroblast migration.NOX4 is critical for modulation of the pulmonary myofibroblast phenotype in IPF, probably by modulating the response to TGFbeta1 and PDGF.

We evaluated the effects of sublethal Escherichia coli endotoxemia with or without concomitant administration of N-acetylcysteine, an antioxidant agent, on diaphragmatic strength, endurance, and malondialdehyde (MDA) content in rats. One hundred ninety rats were inoculated subcutaneously on 2 successive days with 0.6 and 1.2 mg/100 g body weight of E. coli lipopolysaccharide respectively (E animals, n = 100) or saline (C group, n = 90). E and C animals were divided into two groups based on administration of endotoxin or saline alone (E group, n = 55; C group, n = 47, respectively) or endotoxin or saline plus N-acetylcysteine (1 g/kg body weight/day intraperitoneally) (E-NAC group, n = 45; C-NAC group, n = 43, respectively). Diaphragmatic strength was assessed in vivo 48 h after the first endotoxin or saline administration by measuring the transdiaphragmatic pressure (Pdl) generated during electrical stimulation of the phrenic nerves at 0.5, 10, 20, 30, 50, and 100 Hz. Endurance index was calculated as the percent ratio of Pdl generated after 30 s of phrenic stimulation at 10 Hz divided by the initial force. Diaphragmatic MDA (fluorometric technique) was measured 0, 6, 18, 30, 42, and 48 h after the first dose of endotoxin or saline. Pdl for 50 and 100 Hz was significantly reduced in Group E as compared with group C. This phenomenon was associated with a reduced endurance performance as assessed by a lower diaphragmatic endurance index in E as compared with C animals (90.9 +/- 4.2 versus 114.3 +/- 4.1 respectively; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

International audience; Nanotechnology, defined as techniques aimed to design, characterize and produce materials on a nanometer scale, is a fast-growing field today. Nanomaterials are made of nanoobjects (nanoparticles, nanofibers, nanotubes...). The nanoscale confers on these materials their novel, hitherto unknown, chemical and physical properties by the laws of quantum physics which are essentially expressed on this scale. Nanotechnology applications are numerous (e.g., cosmetics, industry and medicine) and they keep growing. We can safely predict that the production and utilization of nanomaterials will increase greatly in the years to come. Nonetheless, the same properties that make these nanomaterials very attractive are a source of concern: there are questions about their potential toxicity, their long-term side effects, and their biodegradability. These questions are based on knowledge of the toxic effects of micrometric particles in air pollution and the fear that these effects will be amplified because of the nanometric size of the new materials. We present in this article a global but not exhaustive summary of current knowledge. We begin by defining lung penetration, deposition, translocation and elimination of nanoparticles. Finally, we consider the respiratory effects of metallic nanoparticles, titanium dioxide nanoparticles in particular, and carbon nanotubes. In vivo and in vitro experimental studies currently available highlight the existence of biological effects of nanoparticles on the respiratory system with generation of oxidative stress, pro-inflammatory and pro-thrombotic effects and the possible development of fibrosis and pulmonary emphysema or DNA damage. A better understanding of the potential biological effects of nanoparticles is required to implement appropriate preventive measures in the workplace and/or in the general population, if this should be necessary.

International audience; BACKGROUND: All-trans retinoic acid (ATRA) stimulates elastin synthesis by lung fibroblasts and induces alveolar regeneration in animal models of pulmonary emphysema. However, ATRA treatment has had disappointing results in human emphysema. It was hypothesised that a defect in the ATRA signalling pathway contributes to the defect of alveolar repair in the human emphysematous lung. METHODS: Fibroblasts were cultured from the lung of 10 control subjects and eight patients with emphysema. Elastin and retinoic acid receptor (RAR)-beta mRNAs were measured in those cells in the presence of incremental concentrations of ATRA. RARs, retinoic X receptors (RXRs) and cellular retinoic acid binding protein (CRABP) 1 and 2 mRNAs were measured as well as CRABP2 protein content. The effect of CRABP2 silencing on elastin and RAR-beta expression in response to ATRA was measured in MRC5 lung fibroblasts. RESULTS: ATRA at 10(-9) M and 10(-8) M increased median elastin mRNA expression by 182% and 126% in control but not in emphysema fibroblasts. RAR-beta mRNA expression was induced by ATRA in control as well as emphysema fibroblasts. RARs, RXRs and CRABP1 mRNAs were similarly expressed in control and emphysema fibroblasts while CRABP2 mRNA and protein were lower in emphysema fibroblasts. CRABP2 silencing abrogated the induction of elastin but not RAR-beta expression by ATRA in MRC5 fibroblasts. CONCLUSION: Pulmonary emphysema fibroblasts fail to express elastin under ATRA stimulation. CRABP2, which is necessary for elastin induction by ATRA in MRC-5 cells, is expressed at low levels in emphysema fibroblasts. This alteration in the retinoic acid signalling pathway in lung fibroblasts may contribute to the defect of alveolar repair in human pulmonary emphysema. These results are the first demonstration of the involvement of CRABP2 in elastin expression.

We evaluated the effects of a sublethal Escherichia coli endotoxemia with and without concomitant administration of indomethacin on diaphragmatic strength in an in vivo rat model. Ninety-six rats were inoculated subcutaneously on two successive days with 0.3 and 0.6 mg/100 g body weight of E. coli lipopolysaccharide, respectively (E animals, n = 64), or saline (C group, n = 32). E animals were divided into two groups based on subcutaneous administration of endotoxin alone (E group, n = 32) or endotoxin plus indomethacin (2.5 mg/kg body weight/day) (EI group, n = 32). Diaphragmatic strength was evaluated in 14 animals from each group 2 days after the first endotoxin or saline administration. Diaphragmatic strength was assessed by measuring the transdiaphragmatic pressure (Pdi) during electrical stimulation of the phrenic nerves at different frequencies (0.5, 10, 20, 30, 50, and 100 Hz). Lung histologic examination and measurements of lung weights were performed 1 and 2 days after the first endotoxin or saline administration in nine animals of each group each day. A slight increase in the number of neutrophils without alveolar septal thickening and alveolar edema was observed in the lungs of endotoxin-inoculated animals. No differences in the lung weight to body weight ratio nor in the dry to wet weight ratio of the lungs were noted between C, E, and EI groups. Diaphragmatic weight was not different in the three groups, whereas the weights of the extensor digitorum longus, tibialis anterior, and soleus muscles were significantly reduced in E compared with C and EI animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary emphysema is characterized by persistent inflammation and progressive alveolar destruction. The keratinocyte growth factor (KGF) favorably influences alveolar maintenance and repair and possesses anti-inflammatory properties. We aimed to determine whether exogenous KGF prevented or corrected elastase-induced pulmonary emphysema in vivo. Treatment with 5 mg·kg−1·day−1 KGF before elastase instillation prevented pulmonary emphysema. This effect was associated with 1) a sharp reduction in bronchoalveolar lavage fluid total protein and inflammatory cell recruitment, 2) a reduction in the pulmonary expression of the chemokines CCL2 (or monocyte chemoattractant protein-1) and CXCL2 (or macrophage inflammatory protein-2α) and of the adhesion molecules ICAM-1 and VCAM-1, 3) a reduction in matrix metalloproteinase (MMP)-2 and MMP-9 activity at day 3, and 4) a major reduction in DNA damage detected by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) in alveolar cells at day 7. Treatment with KGF after elastase instillation had no effect on elastase-induced emphysema despite the conserved expression of the KGF receptor in the lungs of elastase-instilled animals as determined by immunohistochemistry. In vitro, KGF abolished the elastase-induced increase in CCL2, CXCL2, and ICAM-1 mRNA in the MLE-12 murine alveolar epithelial cell line. We conclude that KGF pretreatment protected against elastase-induced pulmonary inflammation, activation of MMPs, alveolar cell DNA damage, and subsequent emphysema in mice.

Introduction La fumee de cigarette, source de stress oxydant, majore la severite de diverses maladies inflammatoires chroniques par des mecanismes peu connus. Le role pathogene des lymphocytes T CD4+ (LTCD4+) producteurs d’IL17 (Th17) dans est etabli dans ces maladies, dont la bronchopneumopathie chronique obstructive (BPCO), maladie respiratoire inflammatoire chronique dont le principal agent etiologique est le tabagisme. Dans la BPCO, les cellules pulmonaires presentent une senescence prematuree, associee a une inflammation plus importante et a la severite de la maladie. Methodes Les LTCD4+ peripheriques Th17, Th1/Th2 = non-Th17 et Treg de sujets sains sont isoles, puis traites avec du condensat de fumee de cigarette (CFC). L’induction de senescence est evaluee en immunofluorescence par l’expression du marqueur de senescence p16. L’effet des especes reactives de l’oxygene (ERO) est evalue apres traitement par l’anti-oxydant, NAC. La production d’ERO est mesuree par cytometrie en flux par la capacite d’oxydation de la sonde H2DCF-DA. La reponse anti-oxydante est evaluee en RQ-PCR par l’expression des enzymes anti-oxydantes. Resultats L’exposition au CFC induit une expression de p16 plus importante dans les Th17 que dans les autres LTCD4+. Le traitement par NAC previent l’expression de p16, indiquant le role potentiel des ERO contenues dans le CFC. Les Th17 produisent plus d’ERO que les autres LTCD4+ apres exposition au CFC, mais aussi en condition basale. Les resultats de RQ-PCR montrent une moindre expression des enzymes anti-oxydantes (Gpx2, TrxR, HO-1) dans les Th17 par rapport aux Treg, et une expression plus importante d’IL4I1, une mono-amineoxydase productrice d’H2O2. Conclusions Nos resultats indiquent que senescence et susceptibilite a l’agression oxydative pourraient etre liees dans les LTCD4+, et que les Th17 pourraient avoir une plus grande susceptibilite a la senescence induite par le CFC en rapport avec un taux d’ERO plus important par rapport aux autres LTCD4+. Nous analyserons ensuite le secretome inflammatoire des Th17 associe a l’augmentation de p16 apres exposition au CFC, puis nous determinerons si les particularites observees au niveau du secretome et/ou de la reponse oxydative des Th17 chez les sujets sains sont majorees chez les patients BPCO.

Study objective Using the negative expiratory pressure(NEP) method, we have previously shown that patients receiving singlelung transplantation (SLT) for COPD do not exhibit expiratory flowlimitation and have little dyspnea at rest. In the present study, weassessed whether SLT patients exhibit flow limitation, overallhyperinflation, and dyspnea during exercise. Methods Expiratory flow limitation assessed by the NEP method and inspiratorycapacity maneuvers used to determine end-expiratory lung volume (EELV)and end-inspiratory lung volume (EILV) were performed at rest andduring symptom-limited incremental cycle exercise in eight SLTpatients. Results At the time of the study, the mean(± SD) FEV 1 , FVC, functional residual capacity, and totallung capacity (TLC) amounted to 55 ± 14%, 67 ± 12%,137 ± 16%, and 110 ± 11% of predicted, respectively. At rest,all patients did not experience expiratory flow limitation and werewithout dyspnea. At peak exercise, the maximal mechanical power outputand maximal oxygen consumption amounted to 72 ± 20% and 65 ± 8%of predicted, respectively, with a maximal dyspnea Borg score of6 ± 3. All but one patient exhibited flow limitation and dynamichyperinflation; the EELV and EILV amounted to 74 ± 5% and95 ± 9% TLC, respectively. The patient who did not exhibit flowlimitation during exercise had the lowest dyspnea score. Conclusion Most SLT patients for COPD exhibit expiratoryflow limitation and dynamic hyperinflation during exercise, whereasmaximal dyspnea is variable.

Application of negative pressure at the mouth during tidal expiration (NEP) provides a simple, rapid, noninvasive method for detecting expiratory flow limitation during spontaneous breathing. Patients in whom NEP elicits an increase in flow throughout expiration are not flow-limited (FL). In contrast, patients in whom application of NEP does not elicit an increase in flow during most or part of tidal expiration are considered FL. We have used the NEP technique to assess the prevalence of expiratory flow limitation during resting breathing in sable asthmatic patients in both the seated and supine positions. In patients in the sitting position, we have also assessed flow limitation with the conventional method, based on comparison of tidal and maximal expiratory flow-volume (MEFV) curves. We studied 13 patients (FEV1 range: 48 to 94% predicted) with both the NEP and conventional techniques. According to the NEP technique, none of the patients was FL in the seated and only two were FL in the supine position. By contrast, on the basis of the conventional method, six of the patients would have been classified as FL in the sitting position. We conclude that: (1) most stable asthmatic patients do not exhibit tidal expiratory flow limitation during resting breathing; and (2) the conventional method for assessing flow limitation may lead to erroneous conclusions.

Expiratory flow limitation and dyspnea during resting breathing are common in patients with severe chronic obstructive pulmonary disease (COPD). Although single lung transplantation (SLT) is used to treat end-stage COPD, its effects on flow limitation and dyspnea are not well established. We assessed expiratory flow-limitation and dyspnea in 13 COPD patients after SLT at rest in the sitting and supine positions by applying negative pressure at the mouth during tidal expiration (negative expiratory pressure [NEP] technique). If NEP increases flow throughout the control tidal volume (VT), flow limitation is absent (not flow limited [NEL]). If NEP does not increase flow during part of the control VT, flow limitation is present. After SLT, lung function improved in all but one patient. Twelve patients were NFL during resting breathing in both positions studied. The patient whose lung function did not improve after SLT was flow-limited (FL) both when seated and supine. This patient also exhibited moderately severe chronic dyspnea (Medical Research Council [MRC] score = 3). In the nine other patients in whom dyspnea was assessed, it was slight (MRC score = 1). In conclusion, after SLT for end-stage COPD, expiratory flow limitation at rest is uncommon in both the seated and supine positions. This is consistent with the finding that after SLT the degree of chronic dyspnea is generally slight.

Introduction : L’intoxication tabagique est un facteur de risque important de developpement de l’emphyseme pulmonaire, probleme majeur de sante publique. Les macrophages alveolaires contribuent a l’inflammation pulmonaire dans l’emphyseme en produisant de nombreuses metalloproteases matricielles et des derives reactifs de l’oxygene impliques dans le desequilibre des balances protease/antiprotease et oxydant/anti-oxydant. Les facteurs de transcription Nrf2/ Bach1 (inducteur/inhibiteur) et la proteine Keap1, impliquee dans la degradation de Nrf2 par le proteasome, jouent un role primordial dans la regulation de l’expression d’enzymes anti-oxydantes comme l’heme oxygenase-1 (HO-1). Nous avons montre qu’une anomalie de la voie Nrf2-Keap1/Bach1 etait associee a une diminution de l’expression d’HO-1, enzyme cle du systeme anti-oxydant pulmonaire, dans les macrophages alveolaires de patients fumeurs presentant un emphyseme severe (Goven Thorax 2008). Le but de ce travail est d’etudier in vitro l’effet de l’exposition prolongee des macrophages a la fumee de cigarette (FC) sur l’expression d’HO-1 et sa regulation via les mitogen-activated protein kinase (MAPK). Methodes : Les macrophages humains derives des monocytes de la lignee THP1 ont ete exposes au condensat de FC (0,01 a 20 µg/ml) en presence ou non des inhibiteurs specifiques des kinases. Les ARNm d’HO-1 et Keap1 ont ete analyses par PCR quantitative en temps reel. Les proteines HO-1, Nrf2, Bach1, Keap1 et les proteines kinases (p38, Erk1/2, JNK) ont ete etudiees par western-blot. Resultats : La FC conduit a une induction precoce d’HO-1 (6 h- 24 h) associee a une translocation nucleaire de Nrf2. Apres 72 heures d’exposition au condensat de FC, l’expression d’HO-1 diminue simultanement a une augmentation de la translocation nucleaire de Bach1 et une diminution de celle de Nrf2, associee a une accumulation cytoplasmique de Keap1. Cette diminution d’HO-1 n’est pas observee avec d’autres inducteurs : H2O2, IL1-β, TNF-α et elastase neutrophile. La diminution d’HO-1 induite par l’exposition prolongee au condensat de FC est associee a une augmentation de l’expression de l’ARNm de Keap1 et de la phosphorylation des proteines kinases (p38, Erk et JNK) qui controlent la degradation de Nrf2 par le proteasome. L’effet de la FC sur l’expression d’HO-1 est aboli uniquement en presence des inhibiteurs specifiques des kinases Erk et JNK, ce qui suggere une implication de ces kinases dans la modulation de l’expression d’HO-1 par le tabac. Conclusions : Ces resultats indiquent que l’exposition prolongee des macrophages humains a la FC conduit a une diminution de l’expression d’HO-1 telle qu’on l’observe dans l’emphyseme pulmonaire severe et qui semble liee a une alteration de l’equilibre Nrf2-Keap1/Bach1 modulee par Erk et JNK.

Introduction : Une expression forte de la NO synthase inductible (iNOS) a ete observee dans le poumon emphysemateux humain. iNOS produit de grandes quantites de NO qui induit la nitrosylation des proteines en reagissant avec l’anion superoxyde. L’anion superoxyde est produit en abondance dans le poumon emphysemateux mais ses sources restent mal connues. L’objectif de ce travail est de determiner si l’expression pulmonaire d’iNOS et l’accumulation de proteines nitrosylees sont necessaires au developpement des lesions d’emphyseme dans un modele animal. Methodes : Des souris C57Bl/6 ont subi une instillation tracheale de serum physiologique ou d’elastase pancreatique porcine et ont ete traitees par un inhibiteur pharmacologique d’iNOS, le 1 400 W (20 mk/kg/j) ou un placebo. Des souris iNOS-/- ont egalement ete utilisees. L’expression pulmonaire d’iNOS a ete quantifiee par western blot et localisee par microscopie confocale. La nitrosylation des proteines pulmonaires a ete quantifiee par immunofluorescence et localisee par microscopie confocale a l’aide de doubles marquages pour SpC, specifique des pneumocytes de type 2, et MAC3, specifique des macrophages. L’emphyseme a ete quantifie par morphometrie informatisee. Resultats : L’instillation tracheale d’elastase induisait une augmentation de 140 % du contenu pulmonaire de iNOS dont l’expression etait diffuse dans le poumon. L’elastase multipliait par 11,6 le nombre de cellules exprimant les proteines nitrosylees. 83 % de ces cellules exprimaient SpC. L’accumulation de proteines nitrosylees dans le poumon etait inhibee a 73 % par le 1 400 W et reduite de 63 % chez les souris iNOS -/- par rapport aux souris sauvages. L’inactivation pharmacologique ou genetique de iNOS ne protegeait pas de l’emphyseme induit par l’instillation d’elastase. Conclusion : Chez la souris, l’instillation tracheale d’elastase induit une surexpression pulmonaire d’iNOS, responsable de l’accumulation de proteines nitrosylees dans les pneumocytes de type 2. Ces phenomenes ne sont pas necessaires au developpement de l’emphyseme. Par ailleurs, les pneumocytes de type 2 semblent etre la principale source d’anion superoxyde dans ce modele.

The present study was undertaken to determine the effects of 8 days of corticosteroid administration on diaphragmatic atrophy and contractile properties. One hundred sixty rats were divided into a pair-fed (PF) group (n = 80) and a steroid-treated (ST) group (n = 80). The treated rats received a single injection of Kenacort 80 retard (0.1 mg/kg intramuscularly). The experimental period was 8 days. Steroid treatment resulted in a 30% decrease in body weight in the ST group when compared with the PF group. Diaphragmatic mass in the ST group decreased in proportion to body weight (30%) as did the weight of the extensor digitorum longus (EDL). The soleus muscle was unaffected. The diaphragmatic atrophy was associated with a significant decrease (p less than 0.001) in normalized tetanic force as assessed both in vivo and in vitro. Diaphragmatic strength was determined in vivo by measuring transdiaphragmatic pressure (Pdi) during bilateral electrical stimulation of the phrenic nerves at different frequencies (0.5, 10, 20, 30, 50, and 1000 Hz). The force-frequency relationship was also studied in vitro using direct stimulation of costal diaphragmatic strips. In both preparations, twitch and low-frequency force were unaffected, whereas normalized tetanic force in the ST group was markedly reduced compared with that in the PF group (p less than 0.001). Soleus and EDL muscles were also studied in vitro. Although steroid treatment had no effect on the soleus, in the EDL, a slight (11%) decrease in normalized tetanic tension was observed.(ABSTRACT TRUNCATED AT 250 WORDS)