Paclitaxel-induced lung injury and its amelioration by parecoxib sodium

CSF3 aggravates acute exacerbation of pulmonary fibrosis by disrupting alveolar epithelial barrier integrity

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive respiratory disorder characterized by poor prognosis, often presenting with acute exacerbation. The primary cause of death associated with IPF is acute exacerbation of IPF (AE-IPF). However, the pathophysiology of acute exacerbation has not been clearly elucidated yet. This study aims to investigate the underlying pathophysiological molecular mechanism in a mouse AE-PF model. C57BL/6J mice were intratracheally administered bleomycin (BLM, 5 mg/kg) to induce pulmonary fibrosis. After 14 days, lipopolysaccharide (LPS, 2 mg/kg) was injected via the trachea route. Histological assessments, including H&E and Masson staining, as well as inflammatory indicators, were included to evaluate the induction of AE-PF by BLM and LPS in mice. Transcriptomic profiling of pulmonary tissues identified CSF3 as one of the top 10 upregulated DEGs in AE-PF mice. Indeed, administration of exogenous CSF3 protein exacerbated AE-PF in mice. Mechanistically, CSF3 disrupted alveolar epithelial barrier integrity and permeability by regulating specialized cell adhesion complexes such as tight junctions (TJs) and adherens junctions (AJs) via PI3K/p-Akt/Snail pathway, contributing to the aggravation of AE-PF in mice. Moreover, the discovery of elevated sera CSF3 indicated a notable increase in IPF patients during the exacerbation of the disease. Pearson correlation analysis in IPF patients revealed significant positive associations between CSF3 levels and KL-6 levels, LDH levels, CRP levels, respectively. These results provide mechanistic insights into the role of CSF3 in exacerbating of lung fibrotic disease and indicate monitoring CSF3 levels may aid in early clinical decisions for alternative therapy in the management of rapidly progressing IPF.

Chemotherapy-induced metastasis: molecular mechanisms and clinical therapies

Chemotherapy, the most widely accepted treatment for malignant tumors, is dependent on cell death induced by various drugs including antimetabolites, alkylating agents, mitotic spindle inhibitors, antitumor antibiotics, and hormonal anticancer drugs. In addition to causing side effects due to non-selective cytotoxicity, chemotherapeutic drugs can initiate and promote metastasis, which greatly reduces their clinical efficacy. The knowledge of how they induce metastasis is essential for developing strategies that improve the outcomes of chemotherapy. Herein, we summarize the recent findings on chemotherapy-induced metastasis and discuss the underlying mechanisms including tumor-initiating cell expansion, the epithelial-mesenchymal transition, extracellular vesicle involvement, and tumor microenvironment alterations. In addition, the use of combination treatments to overcome chemotherapy-induced metastasis is also elaborated.

Postoperative complications after esophagectomy for cancer, neoadjuvant chemoradiotherapy compared to neoadjuvant chemotherapy: A single institutional cohort study

Background

Complications after esophagectomy are common and the possible increase in postoperative complications associated with neoadjuvant chemoradiotherapy is of concern. The aim of our study was to analyze if the addition of radiotherapy to neoadjuvant chemotherapy increases the incidence and severity of postoperative complications, including evaluation of the relation between radiation doses to the heart and lungs and postoperative complications.

Methods

The study was based on an institutional surgical database for esophageal cancer. The study period was October 2008 to March 2020. Patients treated with neoadjuvant chemoradiotherapy were compared to patients treated with neoadjuvant chemotherapy and dose/volume parameters for the lungs and heart considered. The primary outcome was 30-day postoperative complications.

Results

During the study period, 274 patients underwent surgery for esophageal cancer, 93 patients after neoadjuvant chemotherapy and 181 patients after neoadjuvant chemoradiotherapy. The median prescribed radiation dose to the planning target volume was 41.4 Gy, the median of the mean lung dose was 6.2 Gy, and the median of the mean heart dose was 20.3 Gy. The addition of radiotherapy to neoadjuvant chemotherapy did not increase the incidence of postoperative complications. Neither were radiation doses to the lungs and heart associated with postoperative complications. Taxane-based chemotherapy regimens were however associated with an increased incidence of postoperative complications.

Conclusions

In our cohort, the addition of neoadjuvant radiotherapy to chemotherapy was not associated with postoperative complications. However, taxane-based chemotherapy regimens, with or without concomitant radiotherapy, were associated with postoperative complications.

Natural Taxanes: From Plant Composition to Human Pharmacology and Toxicity

Biologically active taxanes, present in small- to medium-sized evergreen conifers of various Taxus species, are widely used for their antioxidant, antimicrobial and anti-inflammatory effects, but mostly for their antitumour effects used in the treatment of solid tumours of the breast, ovary, lung, bladder, prostate, oesophagus and melanoma. More of the substances found in Taxus plant extracts have medical potential. Therefore, at the beginning of this review, we describe the methods of isolation, identification and determination of taxanes in different plant parts. One of the most important taxanes is paclitaxel, for which we summarize the pharmacokinetic parameters of its different formulations. We also describe toxicological risks during clinical therapy such as hypersensitivity, neurotoxicity, gastrointestinal, cardiovascular, haematological, skin and renal toxicity and toxicity to the respiratory system. Since the effect of the drug-form PTX is enhanced by various Taxus spp. extracts, we summarize published clinical intoxications and all fatal poisonings for the Taxus baccata plant. This showed that, despite their significant use in anticancer treatment, attention should also be focused on the risk of fatal intoxication due to ingestion of extracts from these plants, which are commonly found in our surroundings.

Paclitaxel-Induced Pneumonitis in Trinidad: A Case Report

Paclitaxel-induced pneumonitis (PIP) is an immune-mediated disease resulting from a delayed hypersensitivity reaction (type IV) to paclitaxel, an anti-microtubule chemotherapeutic drug commonly used to treat breast cancer in both neoadjuvant and adjuvant settings. PIP is diagnosed by exclusion utilizing laboratory work-up, imaging, biopsy studies, and results of antibiotic therapy because there is no single diagnostic test. Ground-glass opacifications on CT, coupled with minimal restrictive disturbance with decreased diffusion on pulmonary function tests (PFTs), negative bronchoalveolar lavage (BAL), and bronchoscopy cultures, may assist physicians in diagnosing paclitaxel-induced pneumonitis. In this report, we describe a case of PIP present in Trinidad, West Indies, which has not been described previously in this region. 

Increased susceptibility of irradiated mice to Aspergillus fumigatus infection via NLRP3/GSDMD pathway in pulmonary bronchial epithelia

Background

Aspergillus fumigatus infection is difficult to diagnose clinically and can develop into invasive pulmonary aspergillosis, which has a high fatality rate. The incidence of Aspergillus fumigatus infection has increased die to widespread application of radiotherapy technology. However, knowledge regarding A. fumigatus infection following radiation exposure is limited, and the underlying mechanism remains unclear. In this study, we established a mouse model to explore the effect of radiation on A. fumigatus infection and the associated mechanisms.

Methods

In this study, a mouse model of A. fumigatus infection after radiation was established by irradiating with 5 Gy on the chest and instilling 5 × 10⁷/ml Aspergillus fumigatus conidia into trachea after 24 h to explore the effect and study its function and mechanism. Mice were compared among the following groups: normal controls (CON), radiation only (RA), infection only (Af), and radiation + infection (RA + Af). Staining analyses were used to detect infection and damage in lung tissues. Changes in protein and mRNA levels of pyroptosis-related molecules were assessed by western blot analysis and quantitative reverse transcription polymerase chain reaction, respectively. Protein concentrations in the serum and alveolar lavage fluid were also measured. An immunofluorescence colocalization analysis was performed to confirm that NLRP3 inflammasomes activated pyroptosis.

Results

Radiation destroyed the pulmonary epithelial barrier and significantly increased the pulmonary fungal burden of A. fumigatus. The active end of caspase-1 and gasdermin D (GSDMD) were highly expressed even after infection. Release of interleukin-18 (IL-18) and interleukin-1β (IL-1β) provided further evidence of pyroptosis. NLRP3 knockout inhibited pyroptosis, which effectively attenuated damage to the pulmonary epithelial barrier and reduced the burden of A. fumigatus.

Conclusions

Our findings indicated that the activation of NLRP3 inflammasomes following radiation exposure increased susceptibility to A. fumigatus infection. Due to pyroptosis in lung epithelial cells, it resulted in the destruction of the lung epithelial barrier and further damage to lung tissue. Moreover, we found that NLRP3 knockout effectively inhibited the pyroptosis and reducing susceptibility to A. fumigatus infection and further lung damage. Overall, our results suggest that NLRP3/GSDMD pathway mediated-pyroptosis in the lungs may be a key event in this process and provide new insights into the underlying mechanism of infection.

Cyclooxygenase-2 deficiency attenuates lipopolysaccharide-induced inflammation, apoptosis, and acute lung injury in adult mice

Many lung diseases are caused by an excessive inflammatory response, and inflammatory lung diseases are often modeled using lipopolysaccharide (LPS) in mice. Cyclooxygenase-2 (COX-2) encoded by the Ptgs2 gene is induced in response to inflammatory stimuli including LPS. The objective of this study was to test the hypothesis that mice deficient in COX-2 (Ptgs2-/-) will be protected from LPS-induced lung injury. Wild-type (WT; CD1 mice) and Ptgs2-/- mice (on a CD1 background) were treated with LPS or vehicle for 24 h. LPS treatment resulted in histological evidence of lung injury, which was attenuated in the Ptgs2-/- mice. LPS treatment increased the mRNA levels for tumor necrosis factor-α, interleukin-10, and monocyte chemoattractant protein-1 in the lungs of WT mice, and the LPS-induced increases in these levels were attenuated in the Ptgs2-/- mice. The protein levels of active caspase-3 and caspase-9 were lower in the LPS-treated lungs of Ptgs2-/- mice than in LPS-treated WT mice, as were the number of terminal deoxynucleotide transferase dUTP nick end labeling-positive cells in lung sections. LPS exposure resulted in a greater lung wet-to-dry weight ratio (W/D) in WT mice, suggestive of pulmonary edema, while in LPS-treated Ptgs2-/- mice, the W/D was not different from controls and less than in LPS-treated WT mice. These results demonstrate that COX-2 is involved in the inflammatory response to LPS and suggest that COX-2 not only acts as a downstream participant in the inflammatory response, but also acts as a regulator of the inflammatory response likely through a feed-forward mechanism following LPS stimulation.

Microtubules as Major Regulators of Endothelial Function: Implication for Lung Injury

Endothelial dysfunction has been attributed as one of the major complications in COVID-19 patients, a global pandemic that has already caused over 4 million deaths worldwide. The dysfunction of endothelial barrier is characterized by an increase in endothelial permeability and inflammatory responses, and has even broader implications in the pathogenesis of acute respiratory syndromes such as ARDS, sepsis and chronic illnesses represented by pulmonary arterial hypertension and interstitial lung disease. The structural integrity of endothelial barrier is maintained by cytoskeleton elements, cell-substrate focal adhesion and adhesive cell junctions. Agonist-mediated changes in endothelial permeability are directly associated with reorganization of actomyosin cytoskeleton leading to cell contraction and opening of intercellular gaps or enhancement of cortical actin cytoskeleton associated with strengthening of endothelial barrier. The role of actin cytoskeleton remodeling in endothelial barrier regulation has taken the central stage, but the impact of microtubules in this process remains less explored and under-appreciated. This review will summarize the current knowledge on the crosstalk between microtubules dynamics and actin cytoskeleton remodeling, describe the signaling mechanisms mediating this crosstalk, discuss epigenetic regulation of microtubules stability and its nexus with endothelial barrier maintenance, and overview a role of microtubules in targeted delivery of signaling molecules regulating endothelial permeability and inflammation.

Chemotherapy-Induced Changes in the Lung Microenvironment: The Role of MMP-2 in Facilitating Intravascular Arrest of Breast Cancer Cells

Previously, we showed that mice treated with cyclophosphamide (CTX) 4 days before intravenous injection of breast cancer cells had more cancer cells in the lung at 3 h after cancer injection than control counterparts without CTX. At 4 days after its injection, CTX is already excreted from the mice, allowing this pre-treatment design to reveal how CTX may modify the lung environment to indirectly affect cancer cells. In this study, we tested the hypothesis that the increase in cancer cell abundance at 3 h by CTX is due to an increase in the adhesiveness of vascular wall for cancer cells. Our data from protein array analysis and inhibition approach combined with in vitro and in vivo assays support the following two-prong mechanism. (1) CTX increases vascular permeability, resulting in the exposure of the basement membrane (BM). (2) CTX increases the level of matrix metalloproteinase-2 (MMP-2) in mouse serum, which remodels the BM and is functionally important for CTX to increase cancer abundance at this early stage. The combined effect of these two processes is the increased accessibility of critical protein domains in the BM, resulting in higher vascular adhesiveness for cancer cells to adhere. The critical protein domains in the vascular microenvironment are RGD and YISGR domains, whose known binding partners on cancer cells are integrin dimers and laminin receptor, respectively.

Susceptibility to SARS-CoV-2 infection in patients undergoing chemotherapy and radiation therapy

The outbreak of the new coronavirus disease (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has rapidly become a public health emergency of international concern, especially affecting the elderly people and patients with chronic disease, such as hypertension and respiratory syndromes. Patients undergoing chemotherapy treatment (e.g., bleomycin, cyclophosphamide, methotrexate, monoclonal antibodies, and paclitaxel therapy) are vulnerable to the development of respiratory syndromes induced by chemotherapeutic agents and are also more susceptible to viral infections as they are immunosuppressed. Neutropenia is an important risk factor for increased vulnerability to infections, as a respiratory syndrome involves an array of immune cells maintaining the balance between pathogen clearance and immunopathology. However, the differential diagnosis of pulmonary symptoms in cancer patients is broad, with complications being related to the malignancy itself, treatment toxicity, and infections. The risk factors depend on the specific type of cancer, chemotherapy, patient characteristics, and comorbidities. Thus, this review discusses the main events implicated in immunosuppression caused by chemotherapy and radiation therapy and the association of immunosuppression and other factors with SARS-CoV-2 infection susceptibility in cancer patients; and, importantly, how to deal with this situation in face of the current pandemic scenario.

Radiotherapy challenges in COVID era

The pandemic caused by the new coronavirus (SARS-CoV-2) associated with a disease named COVID-19 by the World Health Organization that began in late 2019 in Wuhan city has become a global public health problem. Only 2 months later, the new virus affected most countries of the world, the consequence being an overload of health systems, especially Intensive Care Units. Considered a category of patients at high risk of developing severe forms of the disease, cancer patients can develop a severe form of the disease, complicated by acute respiratory distress syndrome requiring mechanical ventilation. Radiotherapy, as a treatment included in the multidisciplinary management of cancer for both curative and palliative purposes, is also affected by the COVID-19 pandemic. COVID-19-positive or -suspected patients are a special category for which the decision to postpone treatment should be made based on the particularities of tumor biology and the radiobiological effect of a gap in radiation fractions delivery. Emergencies including spinal cord compressions, tumor bleeding, and brain metastases not responsive to corticosteroid treatment, should be considered a priority but the palliative treatment should be limited from one single fraction to maximum five fractions for spinal cord compression and whole brain radiotherapy. Radiotherapy for brain metastases does not bring a benefit in terms of overall survival for patients with life expectancy of days or weeks and dexamethasone treatment is the correct choice in this situation. In all settings, the approach of radiotherapy treatment must be adapted for both scenarios of an outbreak pandemic, when general measures of social distancing and protection by specific equipment of patients and radiotherapy staff are a priority, but also for a long period of coexistence with the virus with possible new “pandemic waves.”

Role of microRNA-15a-5p/TNFAIP3-interacting protein 2 axis in acute lung injury induced by traumatic hemorrhagic shock

The present study aimed to investigate the role of microRNA (miR)-15a-5p in the pathogenesis of acute lung injury induced by traumatic hemorrhagic shock (THS), and to explore the underlying molecular mechanism. The expression level of miR-15a-5p was detected using reverse transcription-quantitative (RT-qPCR) and the association between miR-15a-5p and TNFAIP3-interacting protein 2 (TNIP2) was revealed using TargetScan and dual luciferase reporter assays. To investigate the effect of miR-15a-5p on THS-induced acute lung injury, a THS rat model was established. Lung capillary permeability and lung edema were then determined. Moreover, proinflammatory factors in the bronchoalveolar lavage fluid (BALF) and serum of the THS rat model were detected using ELISA. In addition, protein levels in the current study were measured via western blotting. It was revealed that miR-15a-5p was significantly upregulated in both patients with THS and samples from the THS rat model. TNIP2 represents a direct target of miR-15a-5p, and it was downregulated in both patients with THS and the THS rat model. Further analyses indicated that downregulation of miR-15a-5p significantly relieved acute lung injury induced by THS, evidenced by a decreased ratio of Evan's blue dye (EBD) in the BALF to EBD in plasma of THS rats, decreased lung permeability index and reduced lung wet/dry ratio. Inhibition of miR-15a-5p also decreased THS-induced upregulation of pro-inflammatory factors. Furthermore, the data revealed that THS-induced NF-κB activation in the lung tissues of rats was inhibited by miR-15a-5p knockdown. Moreover, it was demonstrated that all the effects of miR-15a-5p on THS rats were ablated following TNIP2 silencing. Taken together, the data of the current study indicate that miR-15a-5p downregulation serves a protective role in THS-induced acute lung injury via directly targeting TNIP2.

Drug-induced Interstitial Lung Disease in Breast Cancer Patients: A Lesson We Should Learn From Multi-Disciplinary Integration

Abstract Taxanes represented by paclitaxel and targeted therapy including trastuzumab are two common agents for human epidermal growth factor receptor-2 (HER-2)-positive breast cancer patients. Effectiveness, however, usually comes at the cost of many side effects, some of which are even fatal. Drug-induced interstitial lung diseases (DILDs) comprise a group of drug-induced pulmonary injuries usually caused by using these medications. For DILDs, systemic therapy can be harmful to lung tissues and rapidly threaten the lives of some breast cancer patients. Through the cases from our hospital and related studies in medical databases, we hope readers can learn a lesson from an angle of multi-disciplinary integration based on clinical practice and pharmacological mechanisms to make anti-cancer agents less harmful and reduce the incidence of DILD in breast cancer patients during systemic therapy.

Resveratrol protects the integrity of alveolar epithelial barrier via SIRT1/PTEN/p-Akt pathway in methamphetamine-induced chronic lung injury

Objectives

SIRT1 is an antioxidative factor, but its mechanism in methamphetamine (MA)‐induced lung injury remains unclear. The purpose of this study is to determine whether MA can disrupt the integrity of alveolar epithelial barrier, whether SIRT1 is involved in MA‐induced chronic lung injury and whether Resveratrol (Res) can protect the integrity of alveolar epithelial cells by regulating ROS to activate SIRT1/PTEN/p‐Akt pathway.

Materials and methods

The rats were randomly divided into control group and MA group. Extracted lungs were detected by Western blot, HE staining and immunohistochemistry. The alveolar epithelial cells were treated with MA or/and Res, following by Western blot, LDH leakage assay and flow cytometry. MOE is used for bio‐informatics prediction.

Results

Chronic exposure to MA can cause slower growth ratio of weight, increased RVI and induced lung injury including the reduced number of alveolar sacs and the thickened alveolar walls. MA‐induced apoptosis was associated with SIRT1‐related oxidative stress. Res suppressed ROS levels, activated SIRT1, negatively regulated PTEN, phosphorylated Akt, reduced LDH leakage, increased the expression of ZO‐1 and E‐cadherin and inhibited the apoptosis of alveolar epithelial cells to attenuate MA‐induced higher permeability of alveolar epithelium.

Conclusions

MA disrupted the integrity of alveolar epithelial barrier. Res inhibited oxidative stress and reversed MA‐induced higher permeability and apoptosis of alveolar epithelium by the activation of SIRT1/PTEN/p‐Akt pathway.

Association of cell cycle arrest with anticancer drug-induced epithelial-mesenchymal transition in alveolar epithelial cells

Many drugs exert serious cytotoxic effects on pulmonary tissues. Although several reports have shown an association of epithelial-mesenchymal transition (EMT) with anticancer drug-induced lung injury, mechanisms of these effects are poorly understood. In the present study, we evaluated mechanisms of anticancer drug-induced EMT, with a focus on involvement of cell cycle arrest. We found that methotrexate (MTX) altered mRNA expression levels of many genes as determined by microarray analysis. Gene set enrichment analysis revealed that cell cycle arrest pathways may be associated with MTX-induced EMT. In addition, thymidine (THY) and nocodazole (NOC), which induce cell cycle arrest at S-phase and G2/M-phase, increased mRNA expression levels of α-smooth muscle actin (SMA), an EMT marker. Furthermore, α-SMA protein expression in cells arrested at S- and G2/M-phases by MTX and paclitaxel (PTX) was significantly higher than that in cells at G1. Notably, co-treatment of cells with THY or NOC and EMT-inducing anticancer drugs did not result in additional upregulation of α-SMA mRNA expression. These findings suggested that cell cycle arrest may be closely associated with anticancer drug-induced EMT in alveolar epithelial cells.

Anti-inflammatory effect of tranexamic acid against trauma-hemorrhagic shock-induced acute lung injury in rats

It has been demonstrated that tranexamic acid (TXA), a synthetic derivative of lysine, alleviates lung damage in a trauma-hemorrhagic shock (T/HS) model. Nevertheless, the mechanism of TXA against acute lung injury (ALI) has not deeply elaborated. In this study, we generated a T/HS rat model based on previous research, and TXA (50 mg/kg and 100 mg/kg) was intravenously injected into these rats prior to or post T/HS. The results revealed that the decreased survival rate and impaired lung permeability of the rats caused by T/HS were improved by TXA pretreatment or posttreatment. T/HS-triggered over-generation of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in bronchoalveolar fluid and serum was inhibited by TXA, and the enzymatic activity of myeloperoxidase (MPO) in lung tissues was suppressed by TXA as well. Furthermore, TXA treatment deactivated the poly ADP-ribose polymerase-1 (PARP1)/nuclear factor κB (NF-κB) signaling pathway in the lungs of T/HS rats, as evidenced by increased IκBα expression, and decreased cleaved PARP1, p-p65 (Ser276), p-p65 (Ser529), p-IκBα (ser32/ser36), and intercellular adhesion molecule-1. While the expression level of total p65 did not change after T/HS, its DNA binding activity was strengthened. Both TXA pretreatment and posttreatment suppressed this effect on the DNA binding activity of NF-κB. Taken together, our results reveal that administration of TXA effectively relieves T/HS-induced ALI, at least in part, by attenuating the abnormal pulmonary inflammation.

A water-soluble nucleolin aptamer-paclitaxel conjugate for tumor-specific targeting in ovarian cancer

Paclitaxel (PTX) is among the most commonly used first-line drugs for cancer chemotherapy. However, its poor water solubility and indiscriminate distribution in normal tissues remain clinical challenges. Here we design and synthesize a highly water-soluble nucleolin aptamer-paclitaxel conjugate (NucA-PTX) that selectively delivers PTX to the tumor site. By connecting a tumor-targeting nucleolin aptamer (NucA) to the active hydroxyl group at 2' position of PTX via a cathepsin B sensitive dipeptide bond, NucA-PTX remains stable and inactive in the circulation. NucA facilitates the uptake of the conjugated PTX specifically in tumor cells. Once inside cells, the dipeptide bond linker of NucA-PTX is cleaved by cathepsin B and then the conjugated PTX is released for action. The NucA modification assists the selective accumulation of the conjugated PTX in ovarian tumor tissue rather than normal tissues, and subsequently resulting in notably improved antitumor activity and reduced toxicity.

Parecoxib reduced ventilation induced lung injury in acute respiratory distress syndrome

Background

Cyclooxygenase-2 (COX-2) contributes to ventilation induced lung injury (VILI) and acute respiratory distress syndrome (ARDS). The objective of present study was to observe the therapeutic effect of parecoxib on VILI in ARDS.

Methods

In this parallel controlled study performed at Harbin Medical University, China between January 2016 and March 2016, 24 rats were randomly allocated into sham group (S), volume ventilation group/ARDS (VA), parecoxib/volume ventilation group/ARDS (PVA). Rats in the S group only received anesthesia; rats in the VA and PVA group received intravenous injection of endotoxin to induce ARDS, and then received ventilation. Rats in the VA and PVA groups were treated with intravenous injection of saline or parecoxib. The ratio of arterial oxygen pressure to fractional inspired oxygen (PaO₂/FiO₂), the wet to dry weight ratio of lung tissue, inflammatory factors in serum and bronchoalveolar lavage fluid (BALF), and histopathologic analyses of lung tissue were examined. In addition, survival was calculated at 24 h after VILI.

Results

Compared to the VA group, in the PVA group, PaO₂/FiO₂ was significantly increased; lung tissue wet to dry weight ratio; macrophage and neutrophil counts, total protein and neutrophil elastase levels in BALF; tumor necrosis factor-α, interleukin-1β, and prostaglandin E₂ levels in BALF and serum; and myeloperoxidase (MPO) activity, malondialdehyde levels, and Bax and COX-2 protein levels in lung tissue were significantly decreased, while Bcl-2 protein levels were significantly increased. Lung histopathogical changes and apoptosis were reduced by parecpxib in the PVA group. Survival was increased in the PVA group.

Conclusions

Parecoxib improves gas exchange and epithelial permeability, decreases edema, reduces local and systemic inflammation, ameliorates lung injury and apoptosis, and increases survival in a rat model of VILI.

Localization and pneumococcal alteration of junction proteins in the human alveolar-capillary compartment

Loss of alveolar barrier function with subsequent respiratory failure is a hallmark of severe pneumonia. Although junctions between endo- and epithelial cells regulate paracellular fluid flux, little is known about their composition and regulation in the human alveolar compartment. High autofluorescence of human lung tissue in particular complicates the determination of subcellular protein localization. By comparing conventional channel mode confocal imaging with spectral imaging and linear unmixing, we demonstrate that background fluorescent spectra and fluorophore signals could be rigorously separated resulting in complete recovery of the specific signal at a high signal-to-noise ratio. Using this technique and Western blotting, we show the expression patterns of tight junction proteins occludin, ZO-1 as well as claudin-3, -4, -5 and -18 and adherence junction protein VE-cadherin in naive or Streptococcus pneumoniae-infected human lung tissue. In uninfected tissues, occludin and ZO-1 formed band-like structures in alveolar epithelial cells type I (AEC I), alveolar epithelial cells type II (AEC II) and lung capillaries, whereas claudin-3, -4 and -18 were visualised in AEC II. Claudin-5 was detected in the endothelium only. Claudin-3, -5, -18 displayed continuous band-like structures, while claudin-4 showed a dot-like expression. Pneumococcal infection reduced alveolar occludin, ZO-1, claudin-5 and VE-cadherin but did not change the presence of claudin-3, -4 and -18. Spectral confocal microscopy allows for the subcellular structural analysis of proteins in highly autofluorescent human lung tissue. The thereby observed deterioration of lung alveolar junctional organisation gives a structural explanation for alveolar barrier disruption in severe pneumococcal pneumonia.