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International audience; Obstructive sleep apnea is a common chronic disorder that leads to chronic intermittent hypoxia described as an important factor contributing to the pathogenesis of OSA-related comorbidities. Besides, recent data suggest that intermittent hypoxia can induce adaptative cardiovascular pathways inducing a relative resistance to ischemic insults. Adaptative pathways induced by hypoxia could implicate autophagic processes and Beclin-1, one of the first mammalian autophagy effectors. Thus, activation of autophagy could protect against cardiovascular events in patients with OSA and could be considered as biomarker of a better prognosis.

Introduction: Alveolar type 2 cells (AT2) play a key role in alveolar regeneration after alveolar damage. Mechanisms involved in this process are not well known. Aims and Objectives: Targeting p16INK4a, a cell cycle inhibitor, in AT2 could be a way to promote alveolar regeneration. Methods: In vitro alveolar organoids were obtained by co-culturing EpCAM+ cells (sorted with magnetic beads from lungs of p16INK4a-/- or wild type (WT) mice) with WT lung primary fibroblasts. Colony forming units (CFU), organoid size, organoid types (alveolar, bronchoalveolar by pro-SpC and ACT staining) were quantified at D14 and D21. Organoids from emphysematous mice (elastase model) were compared to organoids from PBS-injected mice as a control with the same genetic background (p16INK4a-/- or WT). In vivo, morphological analysis (mean linear intercept) and AT2 number were quantified in elastase or PBS injected mice at D21 and D90 to assess alveolar destruction and regeneration according to WT or p16INK4a-/- genotype. Results: Organoids made with p16INK4a-/- EpCAM+ cells were as numerous but had an increased size compared to those made from WT EpCAM+ cells at D14 and D21. CFU and organoid size from emphysematous mice were significantly decreased compared to control mice. Number and size of organoids made with p16INK4a-/- EpCAM+cells from emphysematous mice were higher than organoids made with WT EpCAM + cells from emphysematous mice. In vivo, p16INK4a deletion was associated with an increase of AT2 at D21 without a protective effect on alveolar architecture. At D90, p16INK4a-/- mice had less emphysema than WT mice. Conclusions: p16INK4a deletion increases endogenous alveolar regeneration by AT2 cells. Mechanisms involved remain to be determined.

Chronic exposure to environmental pollutants is often associated with systemic inflammation. As such, cigarette smoking contributes to inflammation and lung diseases by inducing senescence of pulmonary cells such as pneumocytes, fibroblasts, and endothelial cells. Yet, how smoking worsens evolution of chronic inflammatory disorders associated with Th17 lymphocytes, such as rheumatoid arthritis, psoriasis, Crohn’s disease, and multiple sclerosis, is largely unknown. Results from human studies show an increase in inflammatory CD4+ Th17 lymphocytes at blood- and pulmonary level in smokers. The aim of the study was to evaluate the sensitivity of CD4+ Th17 lymphocytes to cigarette smoke-induced senescence. Mucosa-homing CCR6+ Th17- were compared to CCR6neg -and regulatory T peripheral lymphocytes after exposure to cigarette smoke extract (CSE). Senescence sensitivity of CSE-exposed cells was assessed by determination of various senescence biomarkers (β-galactosidase activity, p16Ink4a- and p21 expression) and cytokines production. CCR6+ Th17 cells showed a higher sensitivity to CSE-induced senescence compared to controls, which is associated to oxidative stress and higher VEGFα secretion. Pharmacological targeting of ROS- and ERK1/2 signalling pathways prevented CSE-induced senescence of CCR6+Th17 lymphocytes as well as VEGFα secretion. Altogether, these results identify mechanisms by which pro-oxidant environmental pollutants contribute to pro-angiogenic and pathogenic CCR6+Th17 cells, therefore potential targets for therapeutic purposes.

Whether the systemic manifestations observed in Chronic Obstructive Pulmonary Disease (COPD) are ascribable to lung dysfunction or direct effects of smoking is in debate. Structural Equations Modeling (SEM), a causal-oriented statistical approach, could help unraveling the pathways involved, by enabling estimation of direct and indirect associations between variables. The objectives of the study was to investigate the relative impact of smoking and COPD on systemic manifestations, inflammation and telomere length. In 292 individuals (103 women; 97 smokers with COPD, 96 smokers without COPD, 99 non-smokers), we used SEM to explore the pathways between smoking (pack-years), lung disease (FEV1, KCO), and the following parameters: arterial stiffness (aortic pulse wave velocity, PWV), bone mineral density (BMD), appendicular skeletal muscle mass (ASMM), grip strength, insulin resistance (HOMA-IR), creatinine clearance (eGFR), blood leukocyte telomere length and inflammatory markers (Luminex assay). All models were adjusted on age and gender. Latent variables were created for systemic inflammation (inflammatory markers) and musculoskeletal parameters (ASMM, grip strength, BMD). SEM showed that most effects of smoking were indirectly mediated by lung dysfunction: e.g. via FEV1 on musculoskeletal factor, eGFR, HOMA-IR, PWV, telomere length, CRP, white blood cells count (WBC) and inflammation factor, and via KCO on musculoskeletal factor, eGFR and PWV. Direct effects of smoking were limited to CRP and WBC. Models had excellent fit. In conclusion, SEM highlighted the major role of COPD in the occurrence of systemic manifestations while smoking effects were mostly mediated by lung function.

Background: Fetal determinants of airway function, such as in utero exposure to maternal cigarette smoke (CS), may create a predisposition to adult airflow obstruction and chronic obstructive pulmonary disease (COPD) in adulthood. It has been suggested that active smoking in adolescence and preexisting airflow obstruction have synergistic deleterious effects. Objective: We used a mouse model to investigate whether there is a synergistic effect of exposure to CS in utero and during adolescence on lung function. Methods: Female C57Bl/6J mice were exposed to CS or to filtered room air during pregnancy. Exposure to CS began 2 weeks before mating and continued until delivery. After birth, the pups were not exposed to CS until day 21 (D21). Between D21 and D49, corresponding to “adolescence,” litters were randomized for an additional 4 weeks of exposure to CS. Lung morphometry, lung mechanics, and the expression of genes involved in senescence were evaluated in different subsets of mice on D21 and D49. Results: In utero exposure to CS induced significant lung function impairment by D21. CS exposure between D21 and D49 induced significant functional impairment only in mice exposed to CS prenatally. On D49, no difference was observed between subgroups in terms of lung p53, p16, p21, and Bax mRNA levels. Conclusions: Our findings suggest that prenatal and adolescent CS exposure have a synergistic effect on lung function in mice. The combined effect did not appear to be a consequence of early pulmonary senescence. Citation: Drummond D, Baravalle-Einaudi M, Lezmi G, Vibhushan S, Franco-Montoya ML, Hadchouel A, Boczkowski J, Delacourt C. 2017. Combined effects of in utero and adolescent tobacco smoke exposure on lung function in C57Bl/6J mice. Environ Health Perspect 125:392–399; http://dx.doi.org/10.1289/EHP54

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.

Introduction: Lung regeneration is essential for damage recovering after lung injury at different age of life. Whether lipofibroblasts (LIF) are able to enhance endogenous alveolar regeneration once alveoli are damaged remains to be determined. Aim: To determine in a mouse model of bronchopulmonary dysplasia if a lipid switch of fibroblasts to LIF induce a curative lung regeneration. Methods: Wt C57BL/6J mice were exposed to hyperoxia (85% O2) or room air from days 3 to 14 of post-natal life. Rosiglitazone (RGZ), a PPARγ agonist which activates fibroblasts differentiation into LIF, was administered intraperitoneally at a dose of 5µg/g of mice daily, 5 days a week, starting after hyperoxia exposure, until adulthood (D60). Tissues were immunostained with anti-ADRP and anti-proSpC antibodies for LIF and AT2 detection respectively. Number of alveoli were estimated by the mean linear intercept and secondary septation by septal crest number (Weigert). Results: Compared to mice exposed to room air, mice exposed to hyperoxia presented a significant decreased number of LIF in lung associated with an arrested alveolar development revealed by a reduced number of alveoli and a concomitant disruption of secondary septation. Compared to hyperoxic, non-treated mice, RGZ administration increased the number of LIF and AT2 cells in the lung, associated with an increase in the number of alveoli and septal crests at adulthood. Conclusion: Switching fibroblasts towards LIF through PPARγ agonist administration induces lung regeneration after hypoalveolization due to post-natal hyperoxia. Administration of PPARγ agonists can be a new pharmacologic strategy to promote lung recovery after injury.

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.

Baarsma et al. report increased expression and posttranslational modification of the noncanonical ligand WNT-5A in COPD. Fibroblast-derived WNT-5A inhibits canonical WNT–β-catenin–driven alveolar epithelial cell–mediated wound healing and transdifferentiation, and thus contributes to impaired lung regeneration and COPD pathogenesis., Chronic obstructive pulmonary disease (COPD) is a leading cause of death worldwide. One main pathological feature of COPD is the loss of functional alveolar tissue without adequate repair (emphysema), yet the underlying mechanisms are poorly defined. Reduced WNT–β-catenin signaling is linked to impaired lung repair in COPD; however, the factors responsible for attenuating this pathway remain to be elucidated. Here, we identify a canonical to noncanonical WNT signaling shift contributing to COPD pathogenesis. We demonstrate enhanced expression of noncanonical WNT-5A in two experimental models of COPD and increased posttranslationally modified WNT-5A in human COPD tissue specimens. WNT-5A was increased in primary lung fibroblasts from COPD patients and induced by COPD-related stimuli, such as TGF-β, cigarette smoke (CS), and cellular senescence. Functionally, mature WNT-5A attenuated canonical WNT-driven alveolar epithelial cell wound healing and transdifferentiation in vitro. Lung-specific WNT-5A overexpression exacerbated airspace enlargement in elastase-induced emphysema in vivo. Accordingly, inhibition of WNT-5A in vivo attenuated lung tissue destruction, improved lung function, and restored expression of β-catenin–driven target genes and alveolar epithelial cell markers in the elastase, as well as in CS-induced models of COPD. We thus identify a novel essential mechanism involved in impaired mesenchymal–epithelial cross talk in COPD pathogenesis, which is amenable to therapy.

Introduction: Pulmonary emphysema is an aging-related disease. However, the mechanisms underlying this phenomenon still remain poorly unknown. P16Ink4 is a key factor implicated in aging-related diseases. Whether p16 is involved in elastase-induced emphysema in mice remains to be determined. Aim: To determine if p16 deletion protects against elastase-induced emphysema in mice. Methods: Wild-type (WT) and p16-/- mice were instilled with pancreatic porcine elastase and sacrificed three weeks or three months later to address the degree of emphysema (morphometric analysis), alveolar septal thickness, collagen deposition (sirius red) and myofibroblasts content (α smooth muscle actin immunostaining). Results: Three weeks after instillation, elastase induced airspace enlargement in the same way in WT and p16-/- mice. However, three months later, elastase-instilled WT mice showed airspace enlargement and, without modification of collagen deposition while elastase-instilled p16-/- mice have reduced airspace enlargement, and increased septal thickness with enhanced collagen deposition, and more myofibroblasts. Conclusions: p16-/- mice are not immediately but later protected against elastase-induced emphysema, and develop a concomitant alveolar fibrosis suggesting a process of repair partially defective.

Introduction: Air pollution (AP) represents the largest environmental risk for health. Such considerations however rely on the static quantification of only a few individual components of AP, without considering their interactions, chemical reactivity and synergistic toxicity. We therefore developed an innovative approach to analyze the health effects of “real life” model atmospheres at the preclinical level. Here, we report the first results of the feasibility study. Methods: A realistic atmosphere, representative of a 2017 pollution event in Paris, was generated (CESAM atmospheric simulation chamber - cesam.cnrs.fr). The chamber was connected to stalling cabinets where mice were exposed during 6 or 48 hours. Lungs, spleen, adipose tissue, heart, mesenteric ganglions were then harvested to address the expression of detoxification and antioxidant genes, as well as total cell count (TCC) and inflammatory cytokines expression in BAL fluid Results: The atmosphere contained 57.3 µg/m3 particulate matter, 114±11 ppb NO2 and 242±101 ppb O3. No mortality and no weight loss was observed. Increased expression of Ahr, Cyp1a1, Hmox1 and NQO1 was detected in the lungs, and increased TCC and KC concentrations in the BAL. Interestingly, we found extra pulmonary modifications; increased expression of Ahr, Cyp1a1, Hmox1 and NQO1 in the spleen, Hmox1, Cyp1a1 and Cyp1b1 in ganglions, and Hmox1 in the adipose tissue and heart. Limited modifications were detected after 6h. Conclusion: These preliminary results demonstrate the feasibility of our innovative experimental approach, which represents a versatile tool to get a better understanding of AP impacts on health.

Obese patients could be more susceptible to mechanical ventilation (MV)-induced lung injury than non-obese patients due to weight-dependent changes in lung properties. The aim of this study was therefore to evaluate the pulmonary effects of 2 hours low VT MV in a diet-induced obese mice model, with VT calculated on either the actual body weight (VTaw) or the ideal body weight (VTiw) . First, we hypothesized that a MV with VTaw would be associated with altered lung mechanics and an increased lung inflammation. Second, we hypothesised that a MV with a VTiw would preserve lung mechanics and limit lung inflammation. We analyzed lung mechanics and inflammation using bronchoalveolar lavage (BAL) cell counts, flow cytometry tissue analysis and histology. Lung mechanics and inflammation were comparable in control and obese mice receiving VTiw. By contrast, obese mice receiving VTaw had significantly more alterations in lung mechanics, BAL cellularity and lung influx of monocytes as compared to control mice. Their monocyte expression of Gr1 and CD62L was also increased. Alveolar neutrophil infiltration was significantly increased in all obese mice as compared to controls. In conclusion, our findings suggest that protective MV with a VTaw is deleterious, with a marked alteration in lung mechanics and associated lung inflammation as compared to lean mice. With VTiw, lung mechanics and inflammation were close to that of control mice, except for an increased alveolar infiltrate of polymorphonuclear neutrophils. This inflammation might be attenuated by a blunted recruitment of inflammatory cells associated with obesity.

Chronic obstructive pulmonary disease (COPD) is a highly prevalent and devastating condition for which no curative treatment is available. Exaggerated lung cell senescence may be a major pathogenic factor. Here, we investigated the potential role for mTOR signaling in lung cell senescence and alterations in COPD using lung tissue and derived cultured cells from patients with COPD and from age- and sex-matched control smokers. Cell senescence in COPD was linked to mTOR activation, and mTOR inhibition by low-dose rapamycin prevented cell senescence and inhibited the proinflammatory senescence-associated secretory phenotype. To explore whether mTOR activation was a causal pathogenic factor, we developed transgenic mice exhibiting mTOR overactivity in lung vascular cells or alveolar epithelial cells. In this model, mTOR activation was sufficient to induce lung cell senescence and to mimic COPD lung alterations, with the rapid development of lung emphysema, pulmonary hypertension, and inflammation. These findings support a causal relationship between mTOR activation, lung cell senescence, and lung alterations in COPD, thereby identifying the mTOR pathway as a potentially new therapeutic target in COPD.

International audience; No abstract available

BackgroundAn excessive pulmonary inflammatory response could explain the poor prognosis of chronic obstructive pulmonary disease (COPD) patients submitted to invasive mechanical ventilation. The aim of this study was to evaluate the response to normal tidal volume (Vt) mechanical ventilation in a murine model of pulmonary emphysema, which represents the alveolar component of COPD. In this model, two time points associated with different levels of lung inflammation but similar lung destruction, were analyzed.MethodsC57BL/6 mice received a tracheal instillation of 5 IU of porcine pancreatic elastase (Elastase mice) or the same volume of saline (Saline mice). Fourteen (D14) and 21 (D21) days after instillation, mice were anesthetized, intubated, and either mechanically ventilated (MV) with a normal Vt (8 mL/kg) or maintained on spontaneous ventilation (SV) during two hours. We analyzed respiratory mechanics, emphysema degree (mean chord length by lung histological analysis), and lung inflammation (bronchoalveolar lavage (BAL) cellularity, proportion and activation of total lung inflammatory cells by flow cytometry).ResultsAs compared with Saline mice, Elastase mice showed a similarly increased mean chord length and pulmonary compliance at D14 and D21, while BAL cellularity was comparable between groups. Lung mechanics was similarly altered during mechanical ventilation in Elastase and Saline mice. Activated alveolar macrophages CD11bmid were present in lung parenchyma in both Elastase SV mice and Elastase MV mice at D14 but were absent at D21 and in Saline mice, indicating an inflammatory state with elastase at D14 only. At D14, Elastase MV mice showed a significant increase in percentage of neutrophils concomitant with a decrease in percentage of alveolar macrophages in total lung, as compared with Elastase SV mice. Furthermore, alveolar macrophages of Elastase MV mice at D14 overexpressed Gr1, and monocytes showed a trend to overexpression of CD62L, compared with Elastase SV mice.ConclusionsIn an elastase-induced model of pulmonary emphysema, normal Vt mechanical ventilation produced an increase in the proportion of pulmonary neutrophils, and an activation of alveolar macrophages and pulmonary monocytes. This response was observed only when the emphysema model showed an underlying inflammation (D14), reflected by the presence of activated alveolar macrophages CD11bmid.

Chronic obstructive pulmonary disease (COPD) is a highly prevalent and devastating condition for which no curative treatment is available. Exaggerated lung-cell senescence may contribute substantially to the pathogenesis of COPD. Here, we explored the potential role for the mTOR signaling pathway in cell senescence and lung alterations in COPD, using lung specimens and derived cultured cells from patients with COPD and from age- and sex-matched control smokers. Cell senescence in COPD was linked to mTOR activation, and mTOR inhibition by low-dose rapamycin prevented cell senescence and inhibited the pro-inflammatory senescence-associated secretory phenotype. To assess whether mTOR activation was causal in lung pathology, we generated mice with constitutive or conditional deletion of the tuberous sclerosis complex heterodimer TSC1 (a negative regulator of mTOR complex 1), in smooth muscle cells (SMCs), endothelial cells (ECs), or alveolar epithelial cells (AECs). In this model, mTOR activation was sufficient to induce early-onset replicative cell senescence in cultured pulmonary artery SMCs from mice with TSC1 deletion. Mice with conditional TSC1 deletion in ECs or AECs developed lung emphysema, pulmonary hypertension, and inflammation in the absence of any other stimuli and concomitantly with the accumulation of senescent lung cells. Rapamycin prevented all these effects. These results support causal links between mTOR activation, cell senescence, and lung alterations in COPD, thereby identifying the mTOR pathway as a new therapeutic target for COPD. Keywords: mTOR, senescence, COPD

Introduction: Bronchopulmonary dysplasia (BPD), characterized by airspace enlargement, develops in premature infants. BPD leads to persistent lung consequences in adulthood, being considered as an early determinant of adult lung diseases. P16Ink4 is a key factor implicated in aging-related lung diseases and its levels are increased in cord blood cells of preterm infants. Whether p16 is involved in BPD and its persistent consequences at the adult age remains to be determined. Aims: To determine in a mouse model of BPD: 1) if p16 deletion protects against lung alterations in new born and adult mice, and 2) if these effects are mediated by cellular senescence. Methods: Mouse pups were exposed to hyperoxia (85% O2) or room air from day 3 to 14 of life. Morphometry (mean linear intercept), elastin content (Weigert), collagen deposition (sirius red), cell senescence (βgalactosidase activity and p21) and cell proliferation (Ki67) were evaluated. Results: At day 14, hyperoxia induced airspace enlargement and cellular senescence, without modification of collagen deposition, nor cell proliferation. Hyperoxic p16-/- mice were not protected against alveolar disruption, but presented an increased alveolar wall thickness and cell proliferation. At day 60, hyperoxic mice showed persistence of airspace enlargement and senescence, without modification of collagen deposition, nor cellular proliferation. Hyperoxic p16-/- mice have reduced airspace enlargement, but increased collagen deposition, without modulation of senescence markers. Conclusions: P16 did not modulated hyperoxia-induced alveolar disruption at young age but could play a crucial role in BPD consequences in adults. This effect may be independent of cellular senescence.

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.

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; 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.

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

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.

Oxidative stress is thought to play a major role in the pathogenesis of chronic obstructive pulmonary disease, characterized by impaired lung function. A large number (> or =33) of GT repeats (L-allele) in the gene of the powerful antioxidant enzyme heme oxygenase-1 has been associated with susceptibility to accelerated lung function decline. In contrast, beta-carotene may help to protect against accelerated decline. To determine whether high serum levels of beta-carotene might counterbalance the greater susceptibility of L-allele carriers, the authors analyzed the annual decline in forced expiratory volume in 1 second (FEV1) in a general population sample of 523 French subjects (20-44 years, 50% men) examined in 1992 and 2000 as part of the European Community Respiratory Health Survey. Analysis of covariance, adjusted for sex as well as baseline age, body mass index, smoking, and FEV1, showed that, among subjects with low beta-carotene levels, L-allele carriers experienced a steeper mean FEV1 decline than did noncarriers (mean = -58.8, 95% confidence interval: -73.2, -44.5 vs. mean = -34.7, 95% confidence interval: -38.9, -29.8 ml/year) (p = 0.009), whereas among subjects with high beta-carotene levels, the FEV1 decline was not different in L-allele carriers and noncarriers (two-sided p = 0.9). The results suggest that high levels of beta-carotene might counterbalance the effects on FEV1 decline of a genetically determined deficiency in antioxidant response.

Objective To determine the consequences of pharmacologic up-regulation of heme oxygenase 1 (HO-1), and inhibition of HO-1 by injection of an anti–HO-1 small interfering RNA (siRNA), in vivo in the acute phase of a mouse model of nonautoimmune arthritis. Methods In the K/BxN mouse serum transfer model, which mimics human inflammatory arthritis without lymphocyte influence, HO-1 was up-regulated by intraperitoneal injection of cobalt protoporphyrin IX (CoPP), a potent pharmacologic inducer, and was inhibited using a specific siRNA. The clinical progress of arthritis was monitored by measurement of paw thickness. Interleukin-1β (IL-1β), IL-6, tumor necrosis factor α (TNFα), serum antioxidant, and nitric oxide (NO) levels, prostaglandin E2 (PGE2) production, and matrix metalloproteinase 9 (MMP-9) activity were measured in serum. At the end of the experiments, joints were examined for immunohistopathologic changes. Results Intraperitoneal injection of CoPP alleviated disease symptoms, such as joint swelling, cartilage degradation, and proliferation of inflammatory tissue in joints, in the acute phase of inflammatory arthritis. The CoPP-induced expression of HO-1 in the joints and liver was associated with marked decreases in IL-1β, IL-6, and TNFα levels, PGE2 secretion, and MMP-9 activity in serum, and with a marked increase in systemic antioxidant activity. In contrast, NO production in serum and inducible NO synthase expression in chondrocytes were not affected by HO-1 induction. Specific inhibition of HO-1 by in vivo delivery of anti–HO-1 siRNA repressed the protective effects. Conclusion Our data provide the first evidence that pharmacologically induced up-regulation of HO-1 triggers a robust protective antiinflammatory response in a model of nonautoimmune arthritis in mice. This suggests that exogenously induced HO-1 may have potential as therapy in the acute phase of inflammatory arthritis in humans.

Cellular senescence--defined as a stable cell-cycle arrest combined with stereotyped phenotypic changes--might play a causal role in various lung diseases, including chronic obstructive pulmonary disease (COPD), which is predicted to become the third leading cause of death worldwide by 2020. COPD is characterized by slowly progressive airflow obstruction and emphysema due to destruction of the lung parenchyma and is often complicated by pulmonary hypertension (PH). No curative treatment is available. Senescent cells, which accumulate with age, are increased in lungs from patients with COPD and express a robust senescence-associated secretory phenotype (SASP), which is proinflammatory. The aim of this review is to show how senescent cells can drive the lung alterations seen in COPD, which mechanisms may be involved, and whether therapeutic interventions may slow or delay the in vitro cell-senescence process and in vivo lung alterations.

RESUME Les oxydants pourraient etre impliques dans la Physiopathologie de la BPCO (Broncho-Pneumopathie Chronique Obstructive), definie par une diminution des debits aeriens progressive et incompletement reversible. L’HO-1 (heme oxygenase-1 ) est un antioxydant puissant. Il a ete montre qu’un polymorphisme microsatellite du promoteur du gene de l’HO-1 (repetition de paires de bases (GT)) etait capable de moduler la transcription du gene en reponse au stress oxydant. Un promoteur long serait associe a une expression de la proteine HO-1 moindre. Nous avons emis l’hypothese que ce polymorphisme pourrait etre associe au declin de la fonction pulmonaire chez des sujets exposes a une agression oxydante importante comme les fumeurs. Pour tester cette hypothese, nous avons genotype 749 sujets (âges de 20 a 44 ans, 50 % d’hommes et 40 % de non-fumeurs) examines en 1992 et en 2000 dans le cadre du recueil des donnees francaises de l’etude ECRHS. Nous avons compare les porteurs d’allele long (L) ((GT)n ≥ 33 repetitions sur un ou deux allele (s)) aux autres. En longitudinal, nous avons observe que le declin de la fonction pulmonaire etait accelere chez les porteurs de l’allele L par rapport aux autres. En outre, il y avait une interaction entre l’allele L et le tabagisme : le declin de la fonction pulmonaire etait accelere dans le groupe des gros fumeurs porteurs de l’allele L par rapport aux gros fumeurs non-porteurs de l’allele L et aux porteurs de l’allele L non-gros fumeurs. Nos resultats suggerent donc qu’un promoteur long du gene de l’HO-1 serait associe, chez les gros fumeurs, au developpement d’un trouble ventilatoire obstructif.

In the United States sepsis annually affects 700,000 people and accounts for about 210,000 deaths. Respiratory failure has long been known to be a frequent occurrence of this pathological condition and to represent a major contributor to the high associated mortality [1]. This contribution discusses of the effects of sepsis and septic shock on respiratory muscle function and focuses on some of the possible mechanisms involved in the genesis of these effects.

Rationale Chronic obstructive pulmonary disease (COPD) is often associated with age-related systemic abnormalities that adversely affect the prognosis. Whether these manifestations are linked to the lung alterations or are independent complications of smoking remains unclear. Objectives To look for aging-related systemic manifestations and telomere shortening in COPD patients and smokers with minor lung destruction responsible for a decline in the diffusing capacity for carbon monoxide (DLCO) corrected for alveolar volume (KCO). Methods Cross-sectional study in 301 individuals (100 with COPD, 100 smokers without COPD, and 101 nonsmokers without COPD). Measurements and Main Results Compared to control smokers, patients with COPD had higher aortic pulse-wave velocity (PWV), lower bone mineral density (BMD) and appendicular skeletal muscle mass index (ASMMI), and shorter telomere length (TL). Insulin resistance (HOMA-IR) and glomerular filtration rate (GFR) were similar between control smokers and COPD patients. Smokers did not differ from nonsmokers for any of these parameters. However, smokers with normal spirometry but low KCO had lower ASMMI values compared to those with normal KCO. Moreover, female smokers with low KCO, had lower BMD and shorter TL compared to those with normal KCO. Conclusions Aging-related abnormalities in patients with COPD are also found in smokers with minor lung dysfunction manifesting as a KCO decrease. Decreased KCO might be useful, particularly among women, for identifying smokers at high risk for aging-related systemic manifestations and telomere shortening.

Objective: To study the expression (mRNA and protein) and activity of the constitutive isoforms of nitric oxide synthase (NOS1 and NOS3) in a skeletal muscle of septic patients. Design: Prospective study. Setting: An adult trauma/surgical intensive care unit in an urban teaching hospital. Patients: Sixteen septic patients and 21 controls. Interventions: None. Measurements and Main Results: Samples of the rectus abdominis muscle were obtained during surgical procedure. NOS mRNA, protein, and activity were detected by reverse-transcriptase polymerase chain reaction, Western blot, and the conversion of [ 3H ]L-arginine to [ 3H ]L-citrulline, respectively. The main results of this study are as follows: a) Levels of NOS1 mRNA and protein were significantly higher than those of NOS3 in the rectus abdominis muscle of control patients; b) NOS1 expression was down-regulated in septic patients, whereas NOS3 was up-regulated; c) these modulations were associated with a reduction in constitutive NOS activity; and d) modifications of NOS1 and NOS3 protein expression were correlated significantly with the severity of sepsis, assessed by the Simplified Acute Physiology Score II. Conclusions: Sepsis induces reciprocal expressional modifications of NOS1 and NOS3 in human skeletal muscle, which decreases muscular constitutive NOS activity. These modifications may have implications for muscle impairment in septic patients.

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.

We have assessed, by intravital microscopy in rats, the effects of different anaesthetics on diaphragmatic arteriolar diameter. Rats were anaesthetized with etomidate, propofol or thiopental (groups E, P and T, respectively) and the diameters of the arterioles were measured sequentially at baseline and after topical application of either mefenamic acid (MA, 20 mumol litre-1) or N omega-nitro-L-arginine (NNA, 300 mumol litre-1), inhibitors of prostaglandins and nitric oxide, respectively. In group E, baseline arteriolar diameters were significantly higher than those in the two other groups (P0.01). MA and NNA induced significant constriction in the three groups (P0.001). However, whereas constriction induced by NNA was similar in the three groups, constriction induced by MA was significantly higher in group E compared with groups P and T (P0.05). We conclude that diaphragmatic arteriolar diameters in rats were greater during etomidate than during thiopental or propofol anaesthesia. This phenomenon may be mediated by prostaglandins.

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.

Background— Induction of cellular senescence through activation of the p53 tumor suppressor protein is a new option for treating proliferative disorders. Nutlins prevent the ubiquitin ligase MDM2 (murine double minute 2), a negative p53 regulator, from interacting with p53. We hypothesized that cell senescence induced by Nutlin-3a exerted therapeutic effects in pulmonary hypertension (PH) by limiting the proliferation of pulmonary artery smooth muscle cells (PA-SMCs). Methods and Results— Nutlin-3a treatment of cultured human PA-SMCs resulted in cell growth arrest with the induction of senescence but not apoptosis; increased phosphorylated p53 protein levels; and expression of p53 target genes including p21, Bax, BTG2, and MDM2. Daily intraperitoneal Nutlin-3a treatment for 3 weeks dose-dependently reduced PH, right ventricular hypertrophy, and distal pulmonary artery muscularization in mice exposed to chronic hypoxia or SU5416/hypoxia. Nutlin-3a treatment also partially reversed PH in chronically hypoxic or transgenic mice overexpressing the serotonin-transporter in SMCs (SM22-5HTT+ mice). In these mouse models of PH, Nutlin-3a markedly increased senescent p21-stained PA-SMCs; lung p53, p21, and MDM2 protein levels; and p21, Bax, PUMA, BTG2, and MDM2 mRNA levels; but induced only minor changes in control mice without PH. Marked MDM2 immunostaining was seen in both mouse and human remodeled pulmonary vessels, supporting the use of Nutlins as a PH-targeted therapy. PH prevention or reversal by Nutlin-3a required lung p53 stabilization and increased p21 expression, as indicated by the absence of Nutlin-3a effects in hypoxia-exposed p53 −/− and p21 −/− mice. Conclusions— Nutlin-3a may hold promise as a prosenescence treatment targeting PA-SMCs in PH.

The effects of anaesthetics on the microcirculation of the diaphragm are incompletely understood. Therefore, we assessed by in vivo intravital microscopy in rats the action of halothane on diaphragmatic arteriolar diameter and the role of nitric oxide and prostaglandins on halothane-induced diaphragmatic arteriolar diameter. We studied 54 rats anaesthetized with thiopentone. Dose-response curves to topically applied Krebs' solution saturated with halothane at increasing concentrations of 0%, 1%, 3% and 5% were carried out in the presence of an inhibitor of nitric oxide synthesis (N omega-nitro-L-arginine (LNA), 300 mumol litre-1) or inhibitors of prostaglandin synthesis (mefenamic acid 20 mumol litre-1 or indomethacin 20 mol litre-1) or in the absence of any inhibitor. We found dose-dependent arteriolar dilatation which was abolished by mefenamic acid and indomethacin. In contrast, the effect of halothane was not modified by LNA. These data demonstrated that halothane-induced arteriolar dilatation in the diaphragm of the rat was mediated by prostaglandins but not by nitric oxide.

Vol. 214, No. 1, January 2017. Pages [143–163][1]. The authors regret that in their original paper, the left two micrographs in Fig. 7 C appeared as duplicates. The corrected figure appears below. The online HTML and PDF versions of this article have been corrected. The error only remains in the

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.

International audience; Carbon nanotubes (CNT) are emblematic nanomaterials, presenting unique physico-chemical properties, such as mechanical, thermal, or electrical conductivity, that have led to a large number of actual applications and uses, as well as (future) developments in aerospace, automobiles, nanoelectronic, or nanomedicine. CNT are currently used in many devices (computers, aircraft airframe, and sporting goods such as tennis rackets, bicycles, golf irons) and have also emerged as efficient drug delivery carriers in the biomedical and drug delivery fields[1]. Because of these actual and future applications, there's an increasing concern regarding the consequences that could result from human exposure to CNT, particularly at the respiratory level, since it represents a major route of exposure to nanomaterials. This review will highlight the advancement in the actual knowledge on lung toxicities of CNT, and try to better understand the underlying biological mechanisms, as well as the importance of physico-chemical determinants directly related to CNT characteristics.

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.