Smoking Cessation in Mice Does Not Switch off Persistent Lung Inflammation and Does Not Restore the Expression of HDAC2 and SIRT1

Once COPD is established, pulmonary lesions can only progress and smoking cessation by itself is not sufficient to switch off persistent lung inflammation. Similarly, in former-smoker mice, neutrophil inflammation persists and lung lesions undergo progressive deterioration. The molecular mechanisms underlying disease progression and the inefficiency of smoking cessation in quenching neutrophilic inflammation were studied in male C57 Bl/6 mice after 6 months of rest from smoking cessation. As compared with the mice that continued to smoke, the former-smoker mice showed reduced expression of histone deacetylases HDAC2 and SIRT1 and marked expression of p-p38 MAPK and p-Ser10. All these factors are involved in corticosteroid insensitivity and in perpetuating inflammation. Former-smoker mice do show persistent lung neutrophilic influx and a high number of macrophages which account for the intense staining in the alveolar structures of neutrophil elastase and MMP-9 (capable of destroying lung scaffolding) and 8-OHdG (marker of oxidative stress). "Alarmins" released from necrotic cells together with these factors can sustain and perpetuate inflammation after smoking cessation. Several factors and mechanisms all together are involved in sustaining and perpetuating inflammation in former-smoker mice. This study suggests that a better control of COPD in humans may be achieved by precise targeting of the various molecular mechanisms associated with different phenotypes of disease by using a cocktail of drug active toward specific molecules

Lung ultrasound features and relationships with respiratory mechanics of evolving BPD in preterm rabbits and human neonates

Evolving bronchopulmonary dysplasia (BPD) is characterized by impaired alveolarization leading to lung aeration inhomogeneities. Hyperoxia-exposed preterm rabbits have been proposed to mimic evolving BPD; therefore, we aimed to verify if this model has the same lung ultrasound and mechanical features of evolving BPD in human neonates. Semiquantitative lung ultrasound and lung mechanics measurement was performed in 25 preterm rabbits (28days of gestation) and 25 neonates (mean gestational age approximate to 26wk) with evolving BPD. A modified rabbit lung ultrasound score (rLUS) and a validated neonatal lung ultrasound score (WS) were used. Lung ultrasound images were recorded and evaluated by two independent observers blinded to each other's evaluation. Lung ultrasound findings were equally heterogeneous both in rabbits as in human neonates and encompassed all the classical lung ultrasound semiology. Lung ultrasound and histology examination were also performed in 13 term rabbits kept under normoxia as further control and showed the absence of ultrasound and histology abnormalities compared with hyperoxia-exposed preterm rabbits. The interrater absolute agreement for the evaluation of lung ultrasound images in rabbits was very high [ICC: 0.989 (95%Cl: 0.975-0.995); P < 0.0001], and there was no difference between the two observers. Lung mechanics parameters were similarly altered in both rabbits and human neonates. There were moderately significant correlations between airway resistances and lung ultrasound scores in rabbits (rho = 0.519; P = 0.008) and in neonates (rho = 0.409; P = 0.042). In conclusion, the preterm rabbit model fairly reproduces the lung ultrasound and mechanical characteristics of preterm neonates with evolving BPD.NEW & NOTEWORTHY We have reported that hyperoxia-exposed preterm rabbits and human preterm neonates with evolving BPD have the same lung ultrasound appearance, and that lung ultrasound can be fruitfully applied on this model with a brief training. The animal model and human neonates also presented the same relationship between semiquantitative ultrasound-assessed lung aeration and airway resistances. In conclusion, this animal model fairly reproduce evolving BPD as it is seen in clinical practice

Ajulemic acid exerts potent anti-fibrotic effect during the fibrogenic phase of bleomycin lung

Background: Ajulemic acid (AjA) is a synthetic analogue of tetrahydrocannabinol that can prevent and limit progression of skin fibrosis in experimental systemic sclerosis. In this study we investigated whether AjA also prevents and modulates lung fibrosis induced by bleomycin (BLM) when administered in mice during the inflammatory or the fibrogenic phase of the model. Methods: The anti-inflammatory and antifibrotic efficacy of AjA was evaluated in DBA/2 mice treated orally once a day starting either at day 0 (preventive treatment) or at day 8 (therapeutic treatment) after a single intratracheal instillation of BLM. AjA was given at a dose of 1 mg/kg or 5 mg/kg. Mice were sacrificed at day 8, 14 and 21 after BLM and lungs were processed for histology and morphometry, and examined for HO-proline content and for the expression of transforming growth factor beta 1 (TGF-β1), phosphorylated Smad2/3 (pSMAD2/3), connective tissue growth factor (CTGF), alpha-smooth muscle actin (α-SMA) and peroxisome proliferator-activated receptor-gamma (PPAR-γ). Results: In the 1st week after BLM challenge, an acute inflammation characterized by neutrophil and macrophage accumulation was the main change present in lung parenchyma. The "switch" between inflammation and fibrosis occurs between day 8 and 14 after BLM instillation and involves the bronchi and vasculature. In the subsequent week (at day 21 after BLM instillation) bronchiolocentric fibrosis with significant increase of tissue collagen develops. The fibrotic response evaluated by morphometry and quantified as HO-proline in lung tissue at day 21 after BLM treatment was significantly reduced in mice receiving either AjA in the inflammatory or in early fibrogenic phase. AjA induces marked change in the expression pattern of products implicated in fibrogenesis, such as TGF-β1, pSMAD2/3, CTGF and α-SMA. In addition, AjA increases significantly the number of PPAR-γ positive cells and its nuclear localization. Conclusions: AjA treatment, starting either at day 0 or at day 8 after BLM challenge, counteracts the progression of pulmonary fibrosis. The anti-fibrotic effectiveness of AjA is irrespective of timing of compound administration. Further clinical studies are necessary to establish whether AjA may represent a new therapeutic option for treating fibrotic lung diseases

Severe Reduction in Number and Function of Peripheral T Cells Does Not Afford Protection toward Emphysema and Bronchial Remodeling Induced in Mice by Cigarette Smoke

8openThe protein Lck (p56(Lck)) is a Src family tyrosine kinase expressed at all stages of thymocyte development and is required for maturation of T cells. The targeted disruption of Lck gene in mice results in severe block in thymocyte maturation with substantial reduction in the development of CD4(+)CD8(+) thymocytes, severe reduction of peripheral T cells, and disruption of T-cell receptor signaling with defective function of T-cell responses. To investigate the role of T lymphocyte in the development of cigarette smoke-induced pulmonary changes, Lck(-/-) mice and corresponding congenic wild-type mice were chronically exposed to cigarette smoke, and their lungs were analyzed by biochemical, immunologic, and morphometric methods. Smoking mice from both genotypes showed disseminated foci of emphysema and large areas of goblet cell metaplasia in bronchial and bronchiolar epithelium. Morphometric evaluation of lung changes and lung elastin determination confirmed that mice from both genotypes showed the same degree of emphysematous lesions. Thus, cigarette smoke exposure in the presence of severe reduction in number and function of peripheral T cells does not influence the development of pulmonary changes induced by cigarette smoke. The data obtained suggest that innate immunity is a leading actor in the early development of pulmonary changes in smoking mice and that the adaptive immune response may play a role at later stages.openDe Cunto, Giovanna; Lunghi, Benedetta; Bartalesi, Barbara; Cavarra, Eleonora; Fineschi, Silvia; Ulivieri, Cristina; Lungarella, Giuseppe; Lucattelli, MonicaDE CUNTO, Giovanna; Lunghi, Benedetta; Bartalesi, Barbara; Cavarra, Eleonora; Fineschi, Silvia; Ulivieri, Cristina; Lungarella, Giuseppe; Lucattelli, Monic

The cannabinoid WIN55, 212-2 abrogates dermal fibrosis in scleroderma bleomycin model

Objectives: There is increasing evidence that the endocannabinoid system may be involved in pathological fibrosis, and that its modulation might limit fibrotic responses. The aim of this study was to examine the capacity of a synthetic cannabinoid receptor agonist to modify skin fibrosis in the bleomycin mouse model of scleroderma. Methods: Skin fibrosis was induced by local injections of bleomycin in two groups of DBA/2J mice. One group was cotreated with the synthetic cannabinoid WIN55,212-2 at 1 mg/kg/day. Skin fibrosis was evaluated by histology and skin thickness and hydroxyproline content were quantified. Markers of fibroblast activation, including α smooth muscle actin and the profibrotic cytokines transforming growth factor (TGF)β, connective tissue growth factor (CTGF) and platelet-derived growth factor (PDGF)-BB, were examined. Levels of PSMAD2/3, which are crucial in extracellular matrix overproduction, were analysed. Results: Bleomycin treatment induced typical skin fibrosis. Upon WIN55,212-2 treatment dermal fibrosis was completely prevented. Subcutaneous inflammatory cell infiltration, dermal thickness and collagen content resulted similar to those of the control group. The synthetic cannabinoid prevented fibroblasts activation induced by bleomycin, paralleled by a strong inhibition of TGFβ, CTGF and PDGF-BB expression. Phosphorylation of SMAD2/3 was significantly downregulated after WIN55,212-2 exposure. Conclusions: Taken together, the results indicate that the synthetic cannabinoid WIN55,212-2 is capable of preventing skin fibrosis in a mouse model of scleroderma

Synthetic cannabinoid ajulemic acid exerts potent antifibrotic effects in experimental models of systemic sclerosis

Background: Cannabinoids modulate fibrogenesis in scleroderma. Ajulemic acid (AjA) is a non-psychoactive synthetic analogue of tetrahydrocannabinol that can bind the peroxisome proliferator-activated receptor-γ (PPAR-γ). Recent evidence suggests a key role for PPAR-γ in fibrogenesis. Objective: To determine whether AjA can modulate fibrogenesis in murine models of scleroderma. Material and methods: Bleomycin-induced experimental fibrosis was used to assess the antifibrotic effects of AjA in vivo. In addition, the efficacy of AjA in pre-established fibrosis was analysed in a modified model of bleomycin-induced dermal fibrosis and in mice overexpressing a constitutively active transforming growth factor β (TGFβ) receptor I. Skin fibrosis was evaluated by quantification of skin thickness and hydroxyproline content. As a marker of fibroblast activation, α-smooth muscle actin was examined. To study the direct effect of AjA in collagen neosynthesis, skin fibroblasts from patients with scleroderma were treated with increasing concentrations of AjA. Protein expression of PPAR-γ, and its endogenous ligand 15d-PGJ2, and TGFβ were assessed before and after AjA treatment. Results: AjA significantly prevented experimental bleomycin-induced dermal fibrosis and modestly reduced its progression when started 3 weeks into the disease. AjA strongly reduced collagen neosynthesis by scleroderma fibroblasts in vitro, an action which was reversed completely by co-treatment with a selective PPAR-γ antagonist. Conclusions: AjA prevents progression of fibrosis in vivo and inhibits fibrogenesis in vitro by stimulating PPAR-γ signalling. Since therapeutic doses of AjA are well tolerated in humans, it is suggested that AjA as an interesting molecule targeting fibrosis in patients with scleroderma

Effect of roflumilast on inflammatory cells in the lungs of cigarette smoke-exposed mice

<p>Abstract</p> <p>Background</p> <p>We reported that roflumilast, a phosphodiesterase 4 inhibitor, given orally at 5 mg/kg to mice prevented the development of emphysema in a chronic model of cigarette smoke exposure, while at 1 mg/kg was ineffective. Here we investigated the effects of roflumilast on the volume density (V_V) of the inflammatory cells present in the lungs after chronic cigarette smoke exposure.</p> <p>Methods</p> <p>Slides were obtained from blocks of the previous study and V_Vwas assessed immunohistochemically and by point counting using a grid with 48 points, a 20× objective and a computer screen for a final magnification of 580×. Neutrophils were marked with myeloperoxidase antibody, macrophages with Mac-3, dendritic cells with fascin, B-lymphocytes with B220, CD4+ T-cells with CD4+ antibody, and CD8+T-cells with CD8-α. The significance of the differences was calculated using one-way analysis of variance.</p> <p>Results</p> <p>Chronic smoke exposure increased neutrophil V_Vby 97%, macrophage by 107%, dendritic cell by 217%, B-lymphocyte by 436%, CD4+ by 524%, and CD8+ by 417%. The higher dose of roflumilast prevented the increase in neutrophil V_Vby 78%, macrophage by 82%, dendritic cell by 48%, B-lymphocyte by 100%, CD4+ by 98% and CD8+ V_Vby 88%. The lower dose of roflumilast did not prevent the increase in neutrophil, macrophage and B-cell V_Vbut prevented dendritic cells by 42%, CD4+ by 55%, and CD8+ by 91%.</p> <p>Conclusion</p> <p>These results indicate (<it>i</it>) chronic exposure to cigarette smoke in mice results in a significant recruitment into the lung of inflammatory cells of both the innate and adaptive immune system; (<it>ii</it>) roflumilast at the higher dose exerts a protective effect against the recruitment of all these cells and at the lower dose against the recruitment of dendritic cells and T-lymphocytes; (<it>iii</it>) these findings underline the role of innate immunity in the development of pulmonary emphysema and (<it>iiii</it>) support previous results indicating that the inflammatory cells of the adaptive immune system do not play a central role in the development of cigarette smoke induced emphysema in mice.</p

Two mouse models for studying smoke-related interstitial lung diseases

Rationale. Some subgroups of interstitial lung diseases, namely desquamative interstitial pneumonia (DIP), respiratory bronchiolitis-associated interstitial pneumonia (RB-ILD), and pulmonary Langerhans cell histiocytosis, are caused by cigarette smoke (CS) in susceptible individuals. Despite smoke-related interstitial lung diseases (SRILDs) have been subjected to extensive investigation during the last years, very little is know about the pathogenetic mechanisms of these diseases and why only a susceptible minority of tobacco smokers develop a clinically significant disease. Methods & Results. We observed that the combination of chronic CS exposure with targeted mutation of genes involved in the expression of factors important for adaptive immune responses (namely p56LcK), or for the modulation of antioxidant genes (such as p66Shc), results in the development of SRILDs. These mice mimic the histopathological traits, which characterise either DIP or RB—ILD in man. As in human RB-ILD, p66Shc KO mice develop after CS exposure patchy lung changes with a bronchiolocentric distribution characterized by pigmented macrophages within bronchiolar lumina, peribronchiolar inflammation and fibrosis. In p56LcK KO mice, chronic macrophage pneumonia is the main feature. Unlike the previous model, the alveolar septal thickening and inflammation in this DIP model tends to be diffuse and uniform from field to field. Species differences notwithstanding, the data obtained in our mice suggest that DIP cannot be regarded as a late stage of RB—ILD but may represent an earlier stage of cryptogenic fibrosing alveolitis. Conclusions. Further studies on these unique animal models may shed light on the pathogenetic mechanisms and the missing links existing among the various SRILDs and can provide valuable information on both the reversibility and the evolution of the lung changes characterising DIP and/or RB—ILD

Chronic Exposure to Cigarette Smoke Induces Pulmonary Hypertension and Vascular Remodelling in Mice Over−Expressing Protease−Activated Receptor−2 (PAR−2).

INTRODUCTION: The mechanism(s) involved in the development of pulmonary hypertension (PH) in chronic obstructive pulmonary disease is still object of research. Recent studies indicate that cigarette smoke (CS) may have, at least in some individuals, a direct effect on the intrapulmonary vessels with up−regulation of mediators that lead to vascular structural remodelling and dynamic changes in vascular function. A role for proteases in PH has been recently put forward. In the present study, we examined the role of PAR−2 in the pathogenesis of lung vascular remodelling induced in mice by chronic exposure to CS. METHODS: Mice were exposed to the smoke of 3 cigarettes / day, 5 days / week. At various times, lungs were analysed by morphology, morphometry, immunohistochemistry and molecular biology techniques. Ventricular pressure was measured by using a miniature catheter. RESULTS: After 7 months of CS exposure, FVB mice over−expressing PAR−2 developed emphysema associated with PH (~ 45% increase in mean right ventricular pressure). A marked vascular remodelling of the middle and small intrapulmonary vessels preceded the onset of PH. No vascular changes were seen in WT mice, which develop only emphysema after chronic exposure to CS. The effect of tobacco smoke in transgenic PAR−2 mice resulted in an imbalance between vasoconstrictors (especially ET−1) and vasodilators (i.e. VEGF, eNOS and iNOS) and enhanced production of growth factors involved in fibroblast−SMC transaction (PDGF and TGFb) and vascular cell proliferation (PDGF). CONCLUSIONS: PAR−2 signalling can influence the production and the release of many of these factors, which ultimately lead to vascular remodelling and aberrant vascular physiology. The level of expression of PAR−2 may play an important role in the development of PH in human smoker