Intact Lung Tissue Research Articles

Smoking-Mediated miR-301a/IRF1 Axis Controlling Immunotherapy Response in Lung Squamous Cell Carcinoma Revealed by Bioinformatic Analysis.

Smoking is an established risk factor for a variety of malignant tumors, the most well-known of which is lung cancer. Various molecular interactions are known to link tobacco smoke exposure to lung cancer, but new data are still emerging on the effects of smoking on lung cancer development, progression, and tumor response to therapy. In this study, we reveal in further detail the previously established association between smoking and hsa-mir-301a activity in lung squamous cell carcinoma, LUSC. Using different bioinformatic tools, we identified IRF1 as a key smoking-regulated target of hsa-mir-301a in LUSC. We further confirmed this relationship experimentally using clinical LUSC tissue samples and intact lung tissue samples. Thus, increased hsa-mir-301a levels, decreased IRF1 mRNA levels, and their negative correlation were shown in LUSC tumor samples. Additional bioinformatic investigation for potential pathways impacted by such a mechanism demonstrated IRF1's multifaceted role in controlling the antitumor immune response in LUSC. IRF1 was then shown to affect tumor immune infiltration, the expression of immune checkpoint molecules, and the efficacy of immune checkpoint blockade therapy. As a result, here we suggest a smoking-regulated mir301a/IRF1 molecular axis that could modulate the antitumor immune response and immunotherapy efficacy in LUSC, opening up novel opportunities for future research.

Investigation of the Optimal Immunization Dose and Protective Efficacy of an Attenuated and Marker M. bovis-Bovine Herpesvirus Type 1 Combined Vaccine in Rabbits.

Bovine respiratory disease (BRD) is one of the most common diseases in the cattle industry; it is a globally prevalent multifactorial infection primarily caused by viral and bacterial coinfections. In China, Mycoplasma bovis (M. bovis) and bovine herpesvirus type 1 (BoHV-1) are the most notable pathogens associated with BRD. Our previous study attempted to combine the two vaccines and conducted a preliminary investigation of their optimal antigenic ratios. Based on this premise, the research extended its investigation by administering varying vaccine doses in a rabbit model to identify the most effective immunization dosage. After immunization, all rabbits in other immunization dose groups had a normal rectal temperature without obvious clinical symptoms. Furthermore, assays performed on the samples collected from immunized rabbits indicated that there were increased humoral and cellular immunological reactions. Moreover, the histological analysis of the lungs showed that immunized rabbits had more intact lung tissue than their unimmunized counterparts after the challenge. Additionally, there appears to be a positive correlation between the protective efficacy and the immunization dose. In conclusion, the different immunization doses of the attenuated and marker M. bovis HB150 and BoHV-1 gG-/tk- combined vaccine were clinically safe in rabbits; the mix of 2.0 × 108 CFU of M. bovis HB150 and 2.0 × 106 TCID50 BoHV-1 gG-/tk- strain was most promising due to its highest humoral and cellular immune responses and a more complete morphology of the lung tissue compared with others. These findings determined the optimal immunization dose of the attenuated and marker M. bovis HB150 and BoHV-1 gG-/tk- combined vaccine, laying a foundation for its clinical application.

Multimodal Diagnostics of Changes in Rat Lungs after Vaping.

(1) Background: The use of electronic cigarettes has become widespread in recent years. The use of e-cigarettes leads to milder pathological conditions compared to traditional cigarette smoking. Nevertheless, e-liquid vaping can cause morphological changes in lung tissue, which affects and impairs gas exchange. This work studied the changes in morphological and optical properties of lung tissue under the action of an e-liquid aerosol. To do this, we implemented the "passive smoking" model and created the specified concentration of aerosol of the glycerol/propylene glycol mixture in the chamber with the animal. (2) Methods: In ex vivo studies, the lungs of Wistar rats are placed in the e-liquid for 1 h. For in vivo studies, Wistar rats were exposed to the e-liquid vapor in an aerosol administration chamber. After that, lung tissue samples were examined ex vivo using optical coherence tomography (OCT) and spectrometry with an integrating sphere. Absorption and reduced scattering coefficients were estimated for the control and experimental groups. Histological sections were made according to the standard protocol, followed by hematoxylin and eosin staining. (3) Results: Exposure to e-liquid in ex vivo and aerosol in in vivo studies was found to result in the optical clearing of lung tissue. Histological examination of the lung samples showed areas of emphysematous expansion of the alveoli, thickening of the alveolar septa, and the phenomenon of plasma permeation, which is less pronounced in in vivo studies than for the exposure of e-liquid ex vivo. E-liquid aerosol application allows for an increased resolution and improved imaging of lung tissues using OCT. Spectral studies showed significant differences between the control group and the ex vivo group in the spectral range of water absorption. It can be associated with dehydration of lung tissue owing to the hyperosmotic properties of glycerol and propylene glycol, which are the main components of e-liquids. (4) Conclusions: A decrease in the volume of air in lung tissue and higher packing of its structure under e-liquid vaping causes a better contrast of OCT images compared to intact lung tissue.

Lung morphology changes in patients with COVID-induced acute respiratory distress syndrome depending on the respiratory therapy options

Background. Morphologic examination of lung tissue in COVID-related acute respiratory distress syndrome is shown in publications predominantly regarding the course of disease but not the type of respiratory support. The aim of the single center study was to determine the influence of different types of respiratory therapy on morphologic findings in lung tissue of patients, who had died from COVID-19. Material and methods. The examined patients with COVID-related related acute respiratory distress syndrome (n = 30) were divided into three groups. Group 1 included those who received non-invasive lung ventilation in continuous positive airway pressure (CPAP) mode through a face mask (n = 10), group 2 consisted of patients who received oxygen therapy with a flow of 15 l/min through a rebreather mask (n = 10), and group 3 included people who underwent invasive lung ventilation through an endotracheal tube (n = 10). Results. In lung tissue of patients of group 1, we revealed prevalence of edema and hemorrhagic changes as well as discrepancy of diffuse alveolar damage (DAD) manifestations and duration of the disease. So, morphological manifestations of exudative phase of DAD were found even after 14 days of disease, and interstitial pneumonia with fibrosing alveolitis was observed only in 12.5 % of patients. The presence of dystelectasis, compensatory emphysema and thinning of the alveolar wall were typical morphological findings in the patients of group 2. Numerous hyaline membranes covered alveolar walls and led to a decrease in gas exchange area, alveolar-capillary block and were the cause of impaired lung ventilation function. Morphological signs of proliferative phase of DAD in patients of group 3 were accompanied by the development of alveolar fibrosis and secondary bacterial bronchopneumonia, especially in prolonged invasive lung ventilation. Conclusions. Low-flow oxygen therapy may lead to the progression of respiratory failure due to self-damaging of intact lung tissue. We have also revealed negative impact of invasive pulmonary ventilation on the number of bacterial complications and fibrosis stimulation. The most favorable morphologic changes were found in patients with non-invasive CPAP ventilation.

Effect of β-Nicotinamide Adenine Dinucleotide on Acute Allograft Rejection After Rat Lung Transplantation.

Rat single-lung transplantation was performed in 2 groups (n = 8 per group), using Brown-Norway donors and major histocompatibility complex-mismatched Lewis recipients. Recipients of the NAD+ group received 1000 mg/kg NAD+ intraperitoneally before transplantation and daily thereafter until euthanasia, whereas the control group received saline solution. At autopsy on day 5, blood samples were analyzed and the lung allograft was assessed by bronchioalveolar lavage, histology, and immunochemistry. The NAD+ group maintained an intact compliant lung tissue, a strong trend of lower acute cellular rejection (A3 versus A3-A4) and significantly less lymphocytic bronchiolitis (B0-B2R versus B1R-Bx). In addition, a trend of fewer alveolar CD68+ macrophages and significantly fewer interstitial CD163+ macrophages was observed. Bronchoalveolar lavage in the NAD+ group showed significantly fewer proinflammatory cytokines interleukin (IL)-6, IL-13, TNFα, and a protective IL-6/IL-10-ratio. In blood samples, we observed significantly fewer neutrophils, and proinflammatory GRO/KC in the NAD+ group. NAD+ might be a promising substance in prevention of acute allograft rejection in lung transplantation.

Quantitative 3D assessment of the lung cancer microenvironment using multi-resolution open-top light-sheet microscopy.

2616 Background: Non-small cell lung cancer (NSCLC) tissue is a valuable resource for diagnosis, treatment planning, and drug development. Current 2D histopathological techniques introduce under-sampling error (i.e., a single 5 µm section represents 0.5% of a 1 mm thick biopsy), interobserver variability, and failure to capture the biology contained within the entire tissue sample. We have developed a suite of technologies to stain, chemically clarify, image, visualize, and analyze entire, intact lung tissue samples. Herein, we present analysis methods for comprehensive 3D assessment of intact NSCLC tissue. Methods: Human NSCLC tissue, stored frozen in optimal cutting temperature (OCT) compound, was fixed in 4% paraformaldehyde, stained with nuclear (TOPRO-3) and general protein (Eosin) fluorescent dyes, and optically cleared using a modified iDISCO protocol with ethyl cinnamate as the refractive index matching solution. Twenty tissue samples measuring 1-5 mm3 in volume were imaged at 2 µm/pixel resolution with a hybrid open-top light-sheet microscope. Smaller regions of interest (ROIs) with interesting pathologic features were re-imaged at higher resolution, 0.17 µm/pixel. Visualization and analysis was performed using Aivia software, custom spatial analysis software and python scripts. Results: All NSCLC tissue samples were successfully imaged in 3D at both low and high resolution. Computational approaches, such as machine learning, were used to segment and classify tumor cells and lymphocytes within the high resolution ROIs. In one example we quantified a 0.0045 mm3 ROI containing 1x109 voxels. We segmented 1,474 unique objects, and classified 683 (46%) of the objects as lymphocytes and 309 (20%) of the cells as tumor cells. We found that on average the lymphocytes were within 12 µm of the nearest tumor cell. Additionally the tissue was broken into separate lymphocyte dense (58% of volume) and tumor dense regions (42% of volume). Further analysis is in progress to quantify more features, such as tertiary lymphoid structures, stromal cells, and fibrosis over the full 20 sample dataset. Conclusions: We successfully implemented 3D machine learning analysis pipelines using images from intact NSCLC tissue samples measuring up to 5 mm3. The imaging was performed using our custom hybrid open-top light-sheet microscope. This novel method enables us to identify and quantify key histological features such as tumor cells and lymphocytes within the tumor microenvironment. In addition, machine learning driven algorithms clustered cells into distinct tissue regions in 3D which enables a more precise assessment of disease state and heterogeneity. Further investigation is ongoing to link these results to patient outcomes.

Short-term ex vivo tissue culture models help study human lung infectionsA review.

Most studies on human lung infection have been performed using animal models, formalin or other fixed tissues, and in vitro cultures of established cell lines. However, the experimental data and results obtained from these studies may not completely represent the complicated molecular events that take place in intact human lung tissue in vivo. The newly developed ex vivo short-term tissue culture model can mimic the in vivo microenvironment of humans and allow investigations of different cell types that closely interact with each other in intact human lung tissues. Therefore, this kind of model may be a promising tool for future studies of different human lung infections, owing to its special advantages in providing more realistic events that occur in vivo. In this review, we have summarized the preliminary applications of this novel short-term ex vivo tissue culture model, with a particular emphasis on its applications in some common human lung infections.

Solid-phase microextraction of endogenous metabolites from intact tissue validated using a Biocrates standard reference method kit

Improved analytical methods for the metabolomic profiling of tissue samples are constantly needed. Currently, conventional sample preparation methods often involve tissue biopsy and/or homogenization, which disrupts the endogenous metabolome. In this study, solid-phase microextraction (SPME) fibers were used to monitor changes in endogenous compounds in homogenized and intact ovine lung tissue. Following SPME, a Biocrates AbsoluteIDQ assay was applied to make a downstream targeted metabolomics analysis and confirm the advantages of in vivo SPME metabolomics. The AbsoluteIDQ kit enabled the targeted analysis of over 100 metabolites via solid-liquid extraction and SPME. Statistical analysis revealed significant differences between conventional liquid extractions from homogenized tissue and SPME results for both homogenized and intact tissue samples. In addition, principal component analysis revealed separated clustering among all the three sample groups, indicating changes in the metabolome due to tissue homogenization and the chosen sample preparation method. Furthermore, clear differences in free metabolites were observed when extractions were performed on the intact and homogenized tissue using identical SPME procedures. Specifically, a direct comparison showed that 47 statistically distinct metabolites were detected between the homogenized and intact lung tissue samples (P < 0.05) using mixed-mode SPME fibers. These changes were probably due to the disruptive homogenization of the tissue. This study's findings highlight both the importance of sample preparation in tissue-based metabolomics studies and SPME's unique ability to perform minimally invasive extractions without tissue biopsy or homogenization while providing broad metabolite coverage.

The role of Wnt pathway antagonists in early-stage lung adenocarcinoma.

We aimed to examine the expression levels of the genes encoding adenomatous polyposis coli (APC) 1, APC-2, Dickkopf related protein (DKK)-1, DKK-3, secreted frizzled-related protein (SFRP)-2, SFRP-4, and SFRP-5, which play roles in the Wnt signaling pathway, in lung adenocarcinoma and adjacent normal lung tissues and to evaluate their relationships with clinicopathologic factors. The expression levels of genes in formalin-fixed paraffin-embedded samples of tumor tissue and adjacent intact lung tissue from 57 patients who underwent surgery for lung adenocarcinoma between 2011 and 2018 were determined by real-time PCR analysis. The expression levels of the DKK-1 in tumor tissue, especially in stage I-II tumor tissue, were significantly suppressed compared to those in normal tissue (p < 0.025). Whereas DKK-1 expression was suppressed in the tumor tissue of patients with early-stage lung adenocarcinoma, expression of the SFRP-5 in these patients was significantly higher in tumor tissue than in normal tissue (p < 0.039). In our study, opposing regulation was found between the SFRP-5 and DKK-1, which are known to be extracellular antagonists of the Wnt signaling pathway. The SFRP-5 was found to have an oncogenic role in adenocarcinoma development. Studies of the opposing regulation between these genes in early-stage lung adenocarcinoma may shed light on the mechanisms associated with the development of carcinogenesis. The relationships or interactions of these genes may serve as potential therapeutic targets.

Morphological characteristics of pulmonary tuberculosis concurrent with lung cancer

To study the pathogenetic relationship between pulmonary tuberculosis and lung cancer. The investigators examined surgical material from 51 patients (41 men) aged 41-73 years (mean age, 63.7 years) with pulmonary tuberculosis concurrent with lung cancer. They also studied tumors, tuberculous caverns, infiltrates, and foci with surrounding macroscopically intact lung tissue, as well as fibrotic changes by histological, histochemical and immunohistochemical examinations. Previous tuberculosis can be considered as a risk factor for lung cancer. Central cancer was more common in patients with inactive, chronic tuberculosis with a predominance of fibrotic processes in the root of the lung and in its hilar zones. Fibrous-cavernous tuberculosis and cavernous tuberculosis were more frequently concurrent with central cancer; peripheral tumors mainly occurred in infiltrative tuberculosis and tuberculomas. The findings suggest that in a number of cases, cancer and tuberculosis may be anatomically close, developing in the same anatomical unit - the lung. However, this does not indicate an unambiguous etiopathogenetic relationship between pulmonary tuberculosis and lung cancer. The relationships between pulmonary tuberculosis and lung cancer are much more complex and do not fit into the simple scheme of cause-and-effect relations.

Pneumolysis and "Silent Hypoxemia" in COVID-19.

COVID-19 can evolve to a severe lung compromise with life-threatening hypoxemia. The mechanisms involved are not fully understood. Their understanding is crucial to improve the outcomes. Initially, past-experience lead to the implementation of standardized protocols assuming this disease would be the same as SARS-CoV. Impulsive use of ventilators in extreme cases ended up in up to 88% fatality. We compare medical and physiological high altitude acute and chronic hypoxia experience with COVID-19 hypoxemia. A pathophysiological analysis is performed based on literature review and histopathological findings. Application of the Tolerance to Hypoxia formula = Hemoglobin/PaCO2 + 3.01 to COVID-19, enlightens its critical hypoxemia. Pneumolysis is defined as progressive alveolar-capillary destruction resulting from the CoV-2 attack to pneumocytes. The adequate interpretation of the histopathological lung biopsy photomicrographs reveals these alterations. The three theoretical pathophysiological stages of progressive hypoxemia (silent hypoxemia, gasping, and death zone) are described. At high altitude, normal low oxygen saturation (SpO2) levels (with intact lung tissue and adequate acid–base status) could be considered silent hypoxemia. At sea level, in COVID-19, the silent hypoxemia starting at SpO2 ≤ 90% (comparable to a normal SPO2 {88–92%} at 3500 m) suddenly evolves to critical hypoxemia. This, as a consequence of progressive pneumolysis + inflammation + overexpressed immunity + HAPE-type edema resulting in pulmonary shunting. The proposed treatment is based on the improvement of the Tolerance to Hypoxia (Hemoglobin factor), oxygen therapy, inflammation reduction, antibiotics, antitussives, rehydration & anticoagulation if required. Understanding the pathophysiology of COVID-19 may assist in this disease's management.

Immunohistochemical evaluation of surfactant-associated protein in fibrosis-cavernous pulmonary tuberculosis

Background. Despite the progress and development of scientific directions in various fields of medicine, the problem of tuberculosis and its morphological manifestations remains relevant and is not fully disclosed due to complex pathogenesis, the presence of various clinical forms, therapeutic pathomorphosis, torpid to therapy, the presence of relapses. It is known that a surfactant system occupies a special place in the system of local lung protection.Aim. To study the condition of surfactant-assotiated protein A in the foci of specific destruction and in the surrounding intact lung tissue to assess its functional status, degree of respiratory failure and possible dissemination of tuberculous inflammation.Material and Metods. An analysis of 163 lung fragments of the dead or operated on for cavernous pulmonary tuberculosis with active bacterial excretion of 89 fragments and with clinical abacilation – 74 was carried out. Results A morphological study revealed stereotypical dynamic depression of surfactant-associated protein A in all the samples studied, both in the areas of cavernous destruction and pericavernouse zone, and in intact lung tissue. The maximum intensivity of the immunohistochemical expression of this surfactant protein was recorded in the alveolar macrophages, which indicated intensive recycling and utilization of the components of the surfactant.Conclusion. Minimizing the production of surfactant components and its active utilization in intact lung tissue leads to a collapse of the alveoli with subsequent progression of respiratory failure.

Ectopic prolactin production by lung cancer cells as an indicator of aggressive nature of tumors.

e20021 Background: Cancer cells use many unexpected molecular mechanisms to ensure their malignancy, and a comprehensive understanding of cancer cannot be achieved without a global consideration of all oncogenic events. Ectopic activation of tissue-specific hormones accompanies malignant transformation in many cancers. The aim of the study was to determine prolactin (PRL) levels in the blood, tumor and surrounding lung tissues in lung cancer patients of both sexes. Methods: Levels of PRL were measured in the blood and 10% homogenates of the tumor, perifocal tissues and intact lung tissues by radioimmune method using Immunotech kits (Czech Republic). The study included 33 men and 22 women with central and peripheral lung adenocarcinomas (T2-3N0-1M0), mean age 62±3.4 years, all women were menopausal. The comparison group included non-cancer patients (13 men and 12 women) operated on for chronic inflammatory lung diseases. Results: PRL levels in peripheral blood in 74% of men were increased by 3.7 times, and in 85% of women by 5.7 times. Peripheral cancer in men and women had no significant differences in prolactin levels; the hormone distribution was similar in the tumor, perifocal and intact tissues and was on average 1.5 times higher than in lung tissues in patients with inflammatory processes. Women with central cancer were characterized by higher tumor levels of PRL compared to men. In general, both in men and women, PRL levels in perifocal tissues and in intact lung tissue distant from the tumor focus were similar to tumor levels, which could indicate a general change in the organ metabolism, and not a local hormone synthesis by tumor tissues. Conclusions: The detected increase in the PRL content in lung tissues and in the blood may indicate the dysfunction of central regulatory mechanisms and a change in lung metabolism, being one of the links in the causal mechanisms of tumor development.

Immunophenotype of the macrophage population in fibrous, cavernous pulmonary tuberculosis

Objective: to study the immunophenotype of the macrophage population and the mechanisms of their vectorial redistribution in fibrous cavernous pulmonary tuberculosis.Materials and methods. The material for the study was fragments of the fibrous cavern wall and pericavernous lung tissue of the dead or surgical patients diagnosed with fibrous cavernous tuberculosis (n = 163). All patients were divided into 2 main groups: patients with active bacteria excretion (MTB+, n = 84) and patients with clinical abacillation (MTB–, n = 79) for immunohistochemistry with a panel of markers for: macrophages and histiocytes – CD68; vascular growth factor A – VEGF-A; T-helpers – CD4, and T-cytotoxic lymphocytes – CD8.Results. Following the analysis of CD68 expression, the population heterogeneity of macrophages was revealed depending on the intensity of the cytoplasmic reaction, functional activity, localization and quantitative characteristics. Three groups were identified: highly active, moderately active and weakly active. Based on the reaction with vascular growth factor A, it was determined that VEGF+ cells correspond to weakly active CD68+ macrophages and are located on the border between the specific granulation tissue and fibrous layer as well as in the pericavernous zone and intact lung tissue with a statistically significant predominance in patients with MTB– (p &lt; 0.05). Regardless of the scope of bacterial secretion, the number of VEGF+ cells in the lymphoid follicle zone directly correlates with that of CD68+ macrophages in the pericavernous zone (R = 0.68) and indirectly correlates with the number of diffusely scattered VEGF+ cells in the fibrous capsule (R = –0.75). In the meantime, CD68+/VEGF+ are visualized in the zone of CD8+ T-lymphocytes, and CD68+/VEGF- – in the zone of CD4+ cell clusters. Such correlation indicates the redistribution of macrophages into type 2, which has a remodeling effect on the surrounding tissues with the potentiating participation of lymphoid cells.

Induction of Human Lung Mast Cell Apoptosis by Granule Permeabilization: A Novel Approach for Targeting Mast Cells.

Mast cells are implicated as detrimental players in inflammatory lung diseases, particularly asthma. Mast cells respond to activating stimuli by releasing a wide panel of pro-inflammatory compounds that can contribute profoundly to the pathology, and there is currently an unmet need for strategies that efficiently ameliorate harmful effects of mast cells under such conditions. Here, we sought to evaluate a novel concept for targeting human lung mast cells, by assessing the possibility of selectively depleting the lung mast cells by induction of apoptosis. For this purpose, we used lysosomotropic agents, i.e., compounds that are known to permeabilize the secretory granules of mast cells, thereby releasing the contents of the granules into the cytosol. Either intact human lung tissue, purified human lung mast cells or mixed populations of human lung cells were incubated with the lysosomotropic agents mefloquine or siramesine, followed by measurement of apoptosis, reactive oxygen species (ROS) production, and release of cytokines. We show that human lung mast cells were highly susceptible to apoptosis induced by this strategy, whereas other cell populations of the lung were largely refractory. Moreover, we demonstrate that apoptosis induced by this mode is dependent on the production of ROS and that the treatment of lung tissue with lysosomotropic agents causes a decrease in the release of pathogenic cytokines. We conclude that selective apoptosis of human lung mast cells can be accomplished by administration of lysosomotropic agents, thus introducing the possibility of using such drugs as novel therapeutics in the treatment of inflammatory lung disorders such as asthma.

ROCK regulates the intermittent mode of interstitial T cell migration in inflamed lungs

Effector T cell migration through tissues can enable control of infection or mediate inflammatory damage. Nevertheless, the molecular mechanisms that regulate migration of effector T cells within the interstitial space of inflamed lungs are incompletely understood. Here, we show T cell migration in a mouse model of acute lung injury with two-photon imaging of intact lung tissue. Computational analysis indicates that T cells migrate with an intermittent mode, switching between confined and almost straight migration, guided by lung-associated vasculature. Rho-associated protein kinase (ROCK) is required for both high-speed migration and straight motion. By contrast, inhibition of Gαi signaling with pertussis toxin affects speed but not the intermittent migration of lung-infiltrating T cells. Computational modeling shows that an intermittent migration pattern balances both search area and the duration of contacts between T cells and target cells. These data identify that ROCK-dependent intermittent T cell migration regulates tissue-sampling during acute lung injury.

Decellularization of Intact Lung Tissue Through Vasculature and Airways Using Negative and Positive Pressure.

Decellularization allows the production of extracellular matrix (ECM) scaffolds. Here we describe the use of combined positive pressure and negative pressure to drive decellularization reagents into the vasculature and airways, respectively, of structurally intact lungs in order to remove cells and cellular material leaving an intact ECM scaffold.

Roflumilast Prevents the Metabolic Effects of Bleomycin-Induced Fibrosis in a Murine Model

Fibrotic remodeling is a process common to chronic lung diseases such as chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, acute respiratory distress syndrome and asthma. Based on preclinical studies phosphodiesterase 4 (PDE4) inhibitors may exhibit beneficial anti-inflammatory and anti-remodeling properties for the treatment of these respiratory disorders. Effects of PDE4 inhibitors on changes in the lung metabolome in models of pulmonary fibrotic remodeling have not yet been explored. This work studies the effects of the PDE4 inhibitor roflumilast on changes in the lung metabolome in the common murine model of bleomycin-induced lung fibrosis by nuclear magnetic resonance (NMR) metabolic profiling of intact lung tissue. Metabolic profiling reveals strong differences between fibrotic and non-fibrotic tissue. These differences include increases in proline, glycine, lactate, taurine, phosphocholine and total glutathione and decreases in global fatty acids. In parallel, there was a loss in plasma BH4. This profile suggests that bleomycin produces alterations in the oxidative equilibrium, a strong inflammatory response and activation of the collagen synthesis among others. Roflumilast prevented most of these metabolic effects associated to pulmonary fibrosis suggesting a favorable anti-fibrotic profile.

Hyperoxia stimulates the transdifferentiation of type II alveolar epithelial cells in newborn rats.

Supplemental oxygen treatment in preterm infants may cause bronchopulmonary dysplasia (BPD), which is characterized by alveolar simplification and vascular disorganization. Despite type II alveolar epithelial cell (AEC II) damage being reported previously, we found no decrease in the AEC II-specific marker, surfactant protein C (SP-C), in the BPD model in our previous study. We thus speculated that AEC II injury is not a unique mechanism of BPD-related pulmonary epithelial repair dysfunction and that abnormal transdifferentiation can exist. Newborn rats were randomly assigned to model (85% oxygen inhalation) and control groups (room air inhalation). Expressions of AEC I (aquaporin 5, T1α) and AEC II markers (SP-C, SP-B) were detected at three levels: 1) in intact lung tissue, 2) in AEC II isolated from rats in the two groups, and 3) in AEC II isolated from newborn rats, which were further cultured under either hyperoxic or normoxic conditions. In the model group, increased AEC I was observed at both the tissue and cell level, and markedly increased transdifferentiation was observed by immunofluorescent double staining. Transmission electron microscopy revealed morphological changes in alveolar epithelium such as damaged AECs, a fused air-blood barrier structure, and opened tight junctions in the model group. These findings indicate that transdifferentiation of AECs is not suppressed but rather is increased under hyperoxic treatment by compensation; however, such repair during injury cannot offset pulmonary epithelial air exchange and barrier dysfunction caused by structural damage to AECs.

Minute lesions of alveolar damage in lungs of patients with stable idiopathic pulmonary fibrosis.

To investigate the mechanisms underlying the acute exacerbation of idiopathic pulmonary fibrosis, and in particular the role of minute lesions of alveolar damage. We examined surgical lung biopsy samples from 38 patients with stable idiopathic pulmonary fibrosis, and evaluated the association between the foci and development of acute exacerbation. Mild extravasation, probably resulting from lung injury and intra-alveolar oedema fluid, were observed in narrow areas of architecturally intact lung tissue. Minute lesions of alveolar damage were detected in these areas. Alveolar epithelial cells in these lesions were injured. Hypoxia-inducible factor-2α-positive macrophages, tumour necrosis factor-α-positive macrophages and neutrophils had accumulated in alveolar spaces in and around these lesions. Cases were classified into patients without (17) and with (21) minute lesions of alveolar damage. Development to acute exacerbation (five cases) occurred only in patients with minute lesions of alveolar damage (P=0.03). The formation of minute lesions of alveolar damage may be initiated by hypoxia, and such lesions play important roles in the development of acute exacerbation.