Alveolar Cell Hyperplasia Research Articles

Chronic Pulmonary Toxicity Study of Indium‐Tin Oxide and Indium Oxide Following Intratracheal Instillations into the Lungs of Hamsters

The aim of this study was to clarify the chronic toxicological effects of indium-tin oxide (ITO) and indium oxide (In(2)O(3)) on laboratory animals. Male Syrian golden hamsters were intratracheally administered 3 mg/kg or 6 mg/kg of ITO particles, or 2.7 mg/kg or 5.4 mg/kg of In(2)O(3) particles, containing 2.2 mg/kg or 4.5 mg/kg of indium, twice a week, for 8 wk. Control hamsters were given vehicle of distilled water only. The hamsters were euthanized serially up to 78 wk after the final instillation and the toxicological effects were determined. Body weight gain was significantly suppressed in the ITO 6 mg/kg-treated hamsters compared with the control group, but not in the ITO 3 mg/kg-treated or In(2)O(3)-treated hamsters. Relative lung weights among all the indium-treated groups were significantly increased compared to that in the control group throughout the observation period. The serum indium concentration among all the indium-treated groups gradually increased up to the end of the observation period. Histopathologically, foci of slight to severe pulmonary inflammatory response with diffuse alveolar or bronchiolar cell hyperplasia, expansion of the alveolar spaces and interstitial fibrotic proliferation were present in all the indium-treated hamsters and the severity of these lesions worsened with the passage of time. Lung benign adenomas were only manifest in 3 out of 15 of the ITO 6 mg/kg-treated hamsters. The present results clearly demonstrate that ITO and In(2)O(3) particles caused chronic pulmonary toxicity when repeated intratracheal instillations were given to hamsters.

MCP-1 Antibody Treatment Enhances Damage and Impedes Repair of the Alveolar Epithelium in Influenza Pneumonitis

Recent studies have demonstrated an essential role of alveolar macrophages during influenza virus infection. Enhanced mortalities were observed in macrophage-depleted mice and pigs after influenza virus infection, but the basis for the enhanced pathogenesis is unclear. This study revealed that blocking macrophage recruitment into the lungs in a mouse model of influenza pneumonitis resulted in enhanced alveolar epithelial damage and apoptosis, as evaluated by histopathology, immunohistochemistry, Western blot, RT-PCR, and TUNEL assays. Abrogation of macrophage recruitment was achieved by treatment with monoclonal antibody against monocyte chemoattractant protein-1 (MCP-1) after sub-lethal challenge with mouse-adapted human influenza A/Aichi/2/68 virus. Interestingly, elevated levels of hepatocyte growth factor (HGF), a mitogen for alveolar epithelium, were detected in bronchoalveolar lavage samples and in lung homogenates of control untreated and nonimmune immunoglobulin (Ig)G-treated mice after infection compared with anti-MCP-1-treated infected mice. The lungs of control animals also displayed strongly positive HGF staining in alveolar macrophages as well as alveolar epithelial cell hyperplasia. Co-culture of influenza virus-infected alveolar epithelial cells with freshly isolated alveolar macrophages induced HGF production and phagocytic activity of macrophages. Recombinant HGF added to mouse lung explants after influenza virus infection resulted in enhanced BrdU labeling of alveolar type II epithelial cells, indicating their proliferation, in contrast with anti-HGF treatment showing significantly reduced epithelial regeneration. Our data indicate that inhibition of macrophage recruitment augmented alveolar epithelial damage and apoptosis during influenza pneumonitis, and that HGF produced by macrophages in response to influenza participates in the resolution of alveolar epithelium.

Functional Wnt Signaling Is Increased in Idiopathic Pulmonary Fibrosis

BackgroundIdiopathic pulmonary fibrosis (IPF) is a fatal lung disease, characterized by distorted lung architecture and loss of respiratory function. Alveolar epithelial cell injury and hyperplasia, enhanced extracellular matrix deposition, and (myo)fibroblast activation are features of IPF. Wnt/β-catenin signaling has been shown to determine epithelial cell fate during development. As aberrant reactivation of developmental signaling pathways has been suggested to contribute to IPF pathogenesis, we hypothesized that Wnt/β-catenin signaling is activated in epithelial cells in IPF. Thus, we quantified and localized the expression and activity of the Wnt/β-catenin pathway in IPF.Methodology/Principal FindingsThe expression of Wnt1, 3a, 7b, and 10b, the Wnt receptors Fzd1-4, Lrp5-6, as well as the intracellular signal transducers Gsk-3β, β-catenin, Tcf1, 3, 4, and Lef1 was analyzed in IPF and transplant donor lungs by quantitative real-time (q)RT-PCR. Wnt1, 7b and 10b, Fzd2 and 3, β-catenin, and Lef1 expression was significantly increased in IPF. Immunohistochemical analysis localized Wnt1, Wnt3a, β-catenin, and Gsk-3β expression largely to alveolar and bronchial epithelium. This was confirmed by qRT-PCR of primary alveolar epithelial type II (ATII) cells, demonstrating a significant increase of Wnt signaling in ATII cells derived from IPF patients. In addition, Western blot analysis of phospho-Gsk-3β, phospho-Lrp6, and β-catenin, and qRT-PCR of the Wnt target genes cyclin D1, Mmp 7, or Fibronectin 1 demonstrated increased functional Wnt/β-catenin signaling in IPF compared with controls. Functional in vitro studies further revealed that Wnt ligands induced lung epithelial cell proliferation and (myo)fibroblast activation and collagen synthesis.Conclusions/SignificanceOur study demonstrates that the Wnt/β-catenin pathway is expressed and operative in adult lung epithelium. Increased Wnt/β-catenin signaling may be involved in epithelial cell injury and hyperplasia, as well as impaired epithelial-mesenchymal cross-talk in IPF. Thus, modification of Wnt signaling may represent a therapeutic option in IPF.

Wnt-inducible protein (WISP-1) is a key regulator of alveolar epithelial cell hyperplasia in pulmonary fibrosis

Fibrotic lung disease is characterized by distorted lung architecture and severe loss of respiratory function secondary to alveolar epithelial cell (AEC) hyperplasia, enhanced extracellular matrix (ECM) deposition and fibroblast proliferation. Repetitive epithelial injuries with impaired alveolar wound healing and altered AEC gene expression represent a trigger mechanism for development of fibrosis. To reveal gene regulatory networks in lung fibrosis, we compared gene expression profiles of freshly isolated AEC obtained from mice 14 days after saline or bleomycin (BM) instillation using whole genome microarray analysis. Several genes of the Wnt signaling pathway, in particular WISP-1, a member of the CCN family, were highly regulated. WISP-1 protein expression was demonstrated in proliferating AEC in BM-treated lungs by immunofluorescence. When analyzing all six CCN family members, WISP-1 was upregulated the most 14 days after BM challenge, as analyzed by qRT-PCR. To elucidate WISP-1 function, cultured primary mouse AEC were stimulated with WISP-1 and demonstrated a 230% increase in proliferation, analyzed by 3H-thymidine incorporation. This was mediated through enhanced phosphorylation, but not expression of protein kinase B (PKB/Akt), as detected by immunoblot. Finally, increased expression of WISP-1 was detected in lung homogenates and isolated AEC from IPF patients, using qRT-PCR. Immunohistochemical analysis of WISP-1 and Ki67 verified the existence of hyperplastic and proliferative AEC expressing WISP-1 in vivo . Our study thus identifies WISP-1 as a novel regulator of AEC injury and repair, and suggests that WISP-1 is a key mediator in pulmonary fibrosis.

L-Ascorbic Acid Protects the Antioxidant Defense System in Nickel- Exposed Albino Rat Lung Tissue

We studied the effect of oral supplementation with L-ascorbic acid (50 mg /100 g body weight (BW) on nickel sulfate (2.0 mg/ 100 g BW, i.p)-induced lipid peroxidation and histopathology in the lung of Wister strain male albino rats. Lipid peroxide and glutathione levels and the activities of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), were estimated. Nickel sulfate administration significantly increased the level of lipid peroxides and decreased all antioxidant enzyme activities. Nickel sulfate treatment also induced (a) loss of normal characteristics and architectural organization, (b) inflammation in bronchioles, (c) alveolar congestion, (d) alveolar cell hyperplasia, and (e) congestion in the lumen. The simultaneous administration of L-ascorbic acid and nickel sulfate improved both lipid peroxidation and the histopathology of lung when compared with rats receiving nickel sulfate alone. The results indicate that L-ascorbic acid prevents nickel-induced alteration of antioxidant defense mechanisms and histopathology of lung tissue.

Apoptosis and Bax Expression are Increased by Coal Dust in the Polycyclic Aromatic Hydrocarbon-Exposed Lung

BackgroundMiners inhaling respirable coal dust (CD) frequently develop coal workers’ pneumoconiosis, a dust-associated pneumoconiosis characterized by lung inflammation and variable fibrosis. Many coal miners are also exposed to polycyclic aromatic hydrocarbon (PAH) components of diesel engine exhaust and cigarette smoke, which may contribute to lung disease in these workers. Recently, apoptosis was reported to play a critical role in the development of another pneumoconiosis of miners, silicosis. In addition, CD was reported to suppress cytochrome P450 1A1 (CYP1A1) induction by PAHs.MethodsWe investigated the hypothesis that apoptosis plays a critical role in lung injury and down-regulation of CYP1A1 induction in mixed exposures to CD and PAHs. We exposed rats intratracheally to 0.0, 2.5, 10.0, 20.0, or 40.0 mg/rat CD and, 11 days later, to intraperitoneal β-naphthoflavone (BNF), a PAH. In another group of rats exposed to CD and BNF, caspase activity was inhibited by injection of the pan-caspase inhibitor Q-VD-OPH [quinoline-Val-Asp (OMe)-CH2-OPH].ResultsIn rats exposed to BNF, CD exposure increased alveolar expression of the proapoptotic mediator Bax but decreased CYP1A1 induction relative to BNF exposure alone. Pan-caspase inhibition decreased CD-associated Bax expression and apoptosis but did not restore CYP1A1 activity. Further, CD-induced lung inflammation and alveolar epithelial cell hypertrophy and hyperplasia were not suppressed by caspase inhibition.ConclusionsCombined BNF and CD exposure increased Bax expression and apoptosis in the lung, but Bax and apoptosis were not the major determinants of early lung injury in this model.

Oleic Acid-associated Bronchiolitis Obliterans-organizing Pneumonia in Beagle Dogs

Accidental intra-airway exposure of dogs with pure oleic acid produced bronchiolitis obliterans and bronchopneumonia. Pulmonary changes included multifocal to coalescing necrosis of bronchioles and adjacent alveoli, hemorrhage, inflammation, and exudation of fibrin. Hyperplasia of bronchiolar and alveolar epithelial cells and proliferation of loose fibrovascular connective tissue formed polyps or plugs of variable size and shape. Polyps in the airways primarily consisted of fibroblasts with loose or myxoid stroma and were variably covered with attenuated epithelial cells. Some polyps had prominent vasculature, mixed inflammatory cell infiltration, and/or necrosis. Polyps or plugs variably effaced bronchioles and adjacent alveoli. The changes closely resembled human bronchiolitis obliterans-organizing pneumonia (BOOP). Controlled intra-airway delivery of oleic acid in dogs may be a potential animal model of obstructive pulmonary diseases such as BOOP or bronchiolitis obliterans.

Acute Respiratory Distress Syndrome Associated With Rabies: A Case Report

Acute respiratory distress syndrome (ARDS) is the first potentially lethal complication in rabies virus infection, although its occurrence is rare. We report on a fatal case of rabies virus infection in a 45-year-old woman from Hu-Nan Province, China. The neurologic signs of limb numbness and water phobia occurred from 61 days after the dog bite; the clinical course was progressive, with the most severe clinical manifestations being fever, encephalitis, and ARDS. The woman expired 12 days after admission to the hospital. An autopsy proved rabies encephalitis, mainly involving the medulla oblongata, the thalamus, part of the pons, the cerebellum, and the hippocampus. The lung pathologic examination revealed the organizing phase of ARDS with diffuse alveolar damage, hyaline membrane formation, type II alveolar cell hyperplasia accompanied by proliferation of fibroblasts and infiltration of mononuclear cells into the interstitial space. Immunohistochemistry stain and reverse transcription-polymerase chain reaction for rabies virus failed to demonstrate the organism in the lung tissue. Strong expression of inducible nitric oxide synthase (iNOS) was detected in the alveolar macrophages. An immunologic mechanism with iNOS expression in the absence of direct invasion of the organism may participate in the pathogenesis of ARDS associated with rabies.

The utility of B72.3, carcinoembryonic antigen, and Leu M-1 in cell blocks

The distinction of bronchioloalveolar carcinoma (BAC) from atypical adenomatous hyperplasia (AAH) or reactive alveolar cell hyperplasia (RAH) can be difficult on aspiration cytology, even when cell block preparations are available. The authors evaluated the usefulness of B72.3, carcinoembryonic antigen (CEA), and Leu M-1 immunostains in differentiating BAC, AAH, and RAH. Immunostains for B72.3, CEA, and Leu M-1 were performed on cell block sections from 11 lung lesions that were diagnosed cytologically as BAC (6 lesions) and "atypical cells, cannot exclude BAC" (5 lesions). Ten histologic sections of AAH and 8 histologic sections of RAH also were stained. Among the six lesions that had an unequivocal cytologic diagnosis of BAC, all sections were positive for two of three immunostains. Tissue follow-up confirmed BAC in all six lesions. Among the five lesions that were diagnosed as "atypical cells, cannot exclude BAC," four lesions were positive for two of three immunostains, and one lesion was negative for all three immunostains. Subsequent tissue follow-up confirmed BAC in four of these lesions. Follow-up histology of the wedge resection on the lesion in the atypical category that was negative for B72.3, CEA, and Leu M-1 showed only AAH. All 10 lesions that had a histologic diagnosis of AAH and 8 lesions that had a histologic diagnosis RAH were negative for B72.3, CEA, and Leu M-1. Positive staining for at least 2 immunostains among B72.3, CEA, and Leu M-1 provided strong supportive evidence for the diagnosis of BAC, and a negative result for all 3 immunostains was helpful in excluding BAC and in differentiating BAC from AAH and RAH.

Protective role of melatonin in ochratoxin a toxicity in rat heart and lung

Ochratoxin A (OTA) is a mycotoxin produced by different fungi. The most pronounced adverse effect of OTA is hepatonephrotoxicity. Melatonin (MEL) has an antioxidant effect and has free-radical scavenger properties. The effects of OTA on heart and lung tissue and possible ameliorating effects of MEL were investigated in rats. Twenty-four rats were allocated to three groups (each with eight rats): control; OTA-treated group (OTA dose 289 microg kg(-1) per day); and OTA + MEL-treated group (MEL dose 10 mg kg(-1) per day). After 30 days of treatment, the histopathological changes in the heart and lung of all groups were examined. Compared with the control rats, myocardial tissue of rats treated with OTA showed extensive cytoplasmic vacuole formation, necrosis of the myocytes, dissolution of the nucleus, clumped fibres, fibrillolysis, swollen myocardial fibres, small haemorrhagic areas and hyperaemic vessels (P <0.05). In addition, lungs of rats treated with OTA showed alveolar congestion, alveolar cell hyperplasia, prominent alveolar septal vessels, variable intensity loss of alveolar architecture, intraparenchymal inflammatory infiltration, intraparenchymal hyperaemic vessels, respiratory epithelial proliferation, perivascular and peribronchial inflammation, pneumonic infiltration, distorted appearance of lung parenchyma and emphysematous areas (P <0.05). In comparison with the OTA groups, the ameliorating effects of MEL in the lung damage parameters were on alveolar cell hyperplasia, prominent alveolar septal vessels, variable intensity loss of alveolar architecture, intraparenchymal inflammatory infiltration, perivascular inflammatory inflammation, distorted appearance of lung parenchyma and focal emphysematous areas in lung (P <0.05). Melatonin also significantly reduced myocardial damage in most of the parameters: extensive cytoplasmic vacuole formation, necrosis of the myocytes, clumped fibres, fibrillolysis, small haemorrhagic areas and hypaeremic vessels in heart (P <0.05). On the other hand, MEL did not lower the degree of damage in lung and heart to the level of the control rats, except for the parameters of the interstitial oedema and small haemorrhagic areas only in myocardial tissue. Histopathological findings showed that OTA induced damage in heart and lung and MEL treatment significantly reduced the degree of damage.

Pulmonary squamous cyst induced by exposure to indium arsenide in hamsters.

Indium arsenide (InAs) belongs to the group of semiconductor materials comprising III-V compounds . With the increasing industrial use of InAs, the question as to whether or not occupational exposure to this material is a potential health hazard has been attracting attention. To date, there is no information regarding adverse health effects on workers arising from their exposure to InAs particles. In our previous study, we confirmed the development of proteinosis-like lesions or localized hyperplastic lesions in the lungs of hamsters which had been induced by exposure to InAs particles. In particular, alveolar or bronchiolar cell hyperplasia with squamous cell metaplasia, squamous cell hyperplasia or squamous cell metaplasia with keratinization were observed when 7.7 mg/kg of InAs was instilled intratracheally, twice a week for a total of 14 times. Accordingly, a further study was undertaken with only half the dose (4 mg/kg). As a result, neoplastic change was never evident. We therefore considered that it was necessary to use a dose in excess of 4 mg/kg of InAs per instillation in order to give rise to a neoplastic response. The aim of the present study was to confirm whether the localized hyperplastic lesions induced by the overloaded condition of InAs particles actually represented a neoplastic response, or not. In this study, 8 mg/kg of InAs was instilled and double the number of hamsters (n=16), compared with that (n=8) in the previous study, received the particles.

Altered surfactant protein A gene expression and protein metabolism associated with repeat exposure to inhaled endotoxin.

Chronically inhaled endotoxin, which is ubiquitous in many occupational and domestic environments, can adversely affect the respiratory system resulting in an inflammatory response and decreased lung function. Surfactant-associated protein A (SP-A) is part of the lung innate immune system and may attenuate the inflammatory response in various types of lung injury. Using a murine model to mimic occupational exposures to endotoxin, we hypothesized that SP-A gene expression and protein would be elevated in response to repeat exposure to inhaled grain dust and to purified lipopolysaccharide (LPS). Our results demonstrate that repeat exposure to inhaled endotoxin, either in the form of grain dust or purified LPS, results in increased whole lung SP-A gene expression and type II alveolar epithelial cell hyperplasia, whereas SP-A protein levels in lung lavage fluid are decreased. Furthermore, these alterations in SP-A gene activity and protein metabolism are dependent on an intact endotoxin signaling system.

COMPARATIVE PULMONARY TOXICITY OF BLASTING SAND AND FIVE SUBSTITUTE ABRASIVE BLASTING AGENTS

Blasting sand is used for abrasive blasting, but its inhalation is associated with pulmonary inflammation and fibrosis. Consequently, safer substitute materials for blasting sand are needed. In a previous study from this laboratory, the comparative pulmonary toxicity of five abrasive blasting substitutes and blasting sand was reported. In this study, the pulmonary toxicity of blasting sand was compared to five additional abrasive blasting substitutes: steel grit, copper slag, nickel slag, crushed glass, and olivine. Exposed rats received by intratracheal instillation 10 mg of respirable-size particles of blasting sand or an abrasive blasting substitute, while controls were instilled with vehicle. Pulmonary inflammation, damage, and fibrosis were examined 28 d postexposure. Pulmonary inflammation was monitored by determining bronchoalveolar lavage polymorphonuclear cell counts and alveolar macrophage activation by chemiluminescence. Pulmonary damage was assessed by acellular bronchoalveolar (BAL) fluid serum albumin concentrations and lactate dehydrogenase activities. Histological examination of lung tissue samples was made to assess the severity and distribution of pulmonary fibrosis, alveolitis, and alveolar epithelial cell hypertrophy and hyperplasia. In comparison to blasting sand, olivine exposed rats had higher levels of pulmonary inflammation and damage with a similar level of fibrosis. Steel grit-exposed rats had lower levels of pulmonary inflammation and damage, and did not develop fibrosis. However, steel grit-exposed rats had a level of epithelial cell hypertrophy and hyperplasia similar to blasting sand. The other abrasive blasting substitutes gave a mixed profile of toxicity. The data demonstrate that steel grit produced less acute pulmonary toxicity than blasting sand or any of the other abrasive blasting substitutes. Notwithstanding, the data also suggest that chronic exposure to steel grit may pose a health risk due to its effects on epithelial cell proliferation in the lung.

Increased anionic peptide distribution and intensity during progression and resolution of bacterial pneumonia.

Anionic peptides (APs) are small anionic antimicrobial peptides composed of 7 aspartic acid residues and are produced in the lungs of humans, sheep, and cattle. Although expression by epithelial cells of some antimicrobial peptides (e.g., beta-defensins) of humans and ruminants is increased in response to acute infection, AP expression is not increased during acute infection, which suggests that the expression of the latter peptide is constitutive. In this study, the degree of AP expression during the progression (acute, subacute, and chronic) of bronchopneumonia was determined. Mannheimia (Pasteurella) haemolytica, a known inducer of bovinebeta-defensins, was inoculated intrabronchially with a fiber-optic bronchoscope in nine 3-month-old sheep, and tissues were collected at 1, 15, and 45 days postinoculation (p.i.); nine control animals received pyrogen-free saline by the same procedure and were killed at the same time points. In the acute group (1 day p.i.), the lungs had lesions typical of bronchopneumonia and the distribution and intensity of AP immunoreactivity (AP-IR) were similar to those of previous studies (minimal intensity and distribution of AP-IR in bronchiolar epithelial cells). In the subacute group (15 days p.i.), there was prominent hyperplasia of bronchiolar and alveolar epithelial cells, and the chronic group (45 days p.i.) had yet more pronounced hyperplasia. In the subacute and chronic groups, the intensity and distribution of AP-IR in the cytoplasm of hyperplastic bronchiolar and type II alveolar cells were significantly increased compared to those of saline-inoculated and contralateral (noninoculated) lung lobes. Although AP expression appears constitutive, the constitutive production of AP is higher in hyperplastic, less differentiated cells than in fully differentiated, mature cells of the respiratory airways. The increased intensity and distribution of AP-IR in immature (hyperplastic) epithelial cells may be a mechanism by which production of a noninducible antimicrobial is increased temporarily during lesion progression and repair. This increased production of AP by hyperplastic cells may protect the lung against further infection until new, fully differentiated epithelial cells are capable of expressing their own inducible array of antimicrobial peptides.

Hyperplasia of Alveolar Neuroendocrine Cells in Rat Lung Carcinogenesis by Silica with Selective Expression of Proadrenomedullin-Derived Peptides and Amidating Enzymes

Pulmonary neuroendocrine (NE) cells are found as clusters called neuroepithelial bodies (NEBs) or as single cells scattered in the respiratory epithelium. They express a variety of bioactive peptides, and they are thought to be the origin of NE lung tumors. Proadrenomedullin N-terminal 20 peptide (PAMP) is a peptide derived from the same precursor as adrenomedullin (AM). AM and PAMP are C-terminally amidated during their processing by a well-characterized amidating enzyme, peptidylglycine alpha-amidating monooxygenase (PAM). We explored AM, PAMP, and PAM expression as markers for NE hyperplasia in three rodent species (Fischer 344 rats, Syrian golden hamsters, and A/J mice) after a single intratracheal instillation of crystalline silica (quartz), which was previously found to induce different reactions in the three species. Rats developed a marked silicosis, with alveolar and bronchiolar hyperplasia and formation of peripheral lung epithelial tumors. Mice developed a moderate degree of silicosis, but not epithelial hyperplasia or tumors. Hamsters showed dust-storage lesions, but not silicosis or tumors. NE cells were immunolabeled for calcitonin gene-related peptide (CGRP), AM, PAMP, and PAM in serial sections of each lung. The numbers of positive NEBs per lung area and positive cells per NEB were quantified. A marked hyperplastic reaction in the NEBs of silica treated rats occurred only in alveolar NEBs, but not in bronchiolar NEBs. From Month 11 onwards, there were marked differences in the number of alveolar NEBs per section and in the number of cells per alveolar NEB immunoreactive for CGRP. No hyperplastic NE cell reaction was observed in silica-treated mice and hamsters. Significant PAMP and PAM expression was seen only in rat hyperplastic alveolar and in bronchiolar NEBs from Month 11 onwards. In E18, rat fetal lung NEBs were found to be strongly positive for PAMP and PAM.

Expression of Matrix Metalloproteinases in Invasive Pulmonary Adenocarcinoma with Bronchioloalveolar Component and Atypical Adenomatous Hyperplasia

To investigate the association between the expression of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) and the clinicopathological features in lepidic and invasive components of adenocarcinoma of the lung, we performed immunostaining for type IV collagen, various MMPs, and TIMPs in 27 cases of invasive adenocarcinomas and 5 cases of atypical adenomatous hyperplasia of alveolar epithelial cells (AAH). Mean extent of lepidic growth was 61% and the survival was significantly better in cases with 50% or more lepidic component. The preservation of type IV collagen in lepidic areas correlated inversely with lymphatic or vascular invasion (P = 0.02 and 0.002, respectively). Five-year survival was reduced in cases showing destruction of type IV collagen (P = 0.004) or expression of MMP-2 (P = 0.008) in lepidic areas. MMP-2 co-localized with MT-1-MMP (its activating enzyme) and TIMP-2 in neoplastic cells. Reactivity for other MMPs and TIMPs did not correlate with destruction of type IV collagen or prognosis. Type IV collagen was preserved in all cases of AAH. MMP-2, but not MT-1-MMP, was expressed in two of the five cases of AAH. Immunostaining for type IV collagen MMP-2 is useful in evaluating the prognosis of the lung.

Effects of Granulocyte Colony-Stimulating Factor on the Development of Inflammation in Bleomycin-Induced Lung Injury.

We investigated the effects of granulocyte colony-stimulating factor (G-CSF) on the development of inflammation in the lung induced by intratracheal administration of bleomycin (BLM, 2 mg/200 μl) in rats. G-CSF (100 μg/kg/day) was subcutaneously administered for 7 days starting from 3 (inflammatory phase) or 14 days (fibrogenic phase) after BLM administration. The administration of G-CSF to BLM-treated rats in the inflammatory phase increased the total lung lesion per unit pulmonary parenchyma, the score of lung fibrosis, the peripheral neutrophil count and the number of neutrophils infiltrating the pulmonary lesion, as well as the severity of other histopathologic changes (edema, hemorrhage and proliferation of myofibroblasts in the alveolar lumen, hyperplasia of bronchial and alveolar epithelial cells, and bronchiolization). Although increases in the peripheral neutrophil count and the number of neutrophils infiltrating the pulmonary lesion were observed following treatment with G-CSF, there were no further increases on lung injury in the fibrogenic phase in BLM-treated rats. These findings suggest that the effects of neutrophils on the lung in the rats treated with G-CSF may be closely related not only to the number of neutrophils, but also to the inflammatory phase of BLM-induced pulmonary lesions.

Interstitial pneumonia in feedlot cattle: concurrent lesions and lack of immunohistochemical evidence for bovine respiratory syncytial virus infection.

The objectives of this study were to describe the nature and distribution of microscopic lung lesions in feedlot cattle with interstitial pneumonia and to determine whether bovine respiratory syncytial virus (BRSV) antigen was present in affected lungs. Lungs with macroscopic lesions compatible with interstitial pneumonia were collected from cattle from 5 west-central Saskatchewan feedlots that had been on feed for greater than 60 days at the time of death. Interstitial pneumonia was most consistently present in dorsal portions of caudal lung lobes and in 21/28 cases (75%) had a multifocal to coalescing distribution. All 28 lungs exhibited hyaline membrane formation and some degree of type II alveolar epithelial cell hyperplasia, consistent with an acute to subacute duration. Twenty-one of 28 cases (75%) had concurrent bronchopneumonia in at least 1 lung lobe; bronchopneumonia was grossly evident in 9/28 cases (32%). Chronic bronchitis or bronchiolitis was present in at least 1 section in 12/28 (43%) of the lungs, and 25/28 (89%) had at least 1 focus of bronchiolitis fibrosa obliterans. Bronchopneumonia and bronchiolitis fibrosa obliterans were markedly less common in 10 sets of bovine lungs obtained from an abattoir. Bovine respiratory syncytial virus antigen was demonstrated using immunohistochemistry in 2/28 cases and was associated with bronchiolar epithelial necrosis that was more severe than the bronchiolar lesions in the BRSV antigen-negative cases. Interstitial pneumonia in feedlot cattle in this study was more frequently associated with suppurative bronchopneumonia and bronchiolitis fibrosa obliterans than with BRSV infection.

Acute Pulmonary Oxygen Toxicity in Rats: Findings and Lung Density Changes in High Resolution Computed Tomography

Purpose : To evaluate imaging findings and lung density changes after 95% oxygen inhalation in rat. Materials and Methods : A total of 18 rats were divided into three groups on the basis of inhalation time: group I(n=6) inhaled 95 % oxygen for 24 hours, and group II(n=6) for 48 hours, group III(n=6) for 60 hours. A control group(n=6) inhaled room air(21 % oxygen). Chest radiograph and high resolution computed tomography were performed, and pathologic and imaging findings were compared. Results : Chest radiograph showed abnormality only in group III. High resolution CT, however, revealed abnormal findings in all three groups : diffuse ground glass opacity in groups I, II and III, additional focal patchy consolidation at the peripheral portion in group II, and diffuse consolidation in group III. Lung density was sig-nificantly higher in group I than in controls(p 0.05). In group III, density was significantly higher than in group II. The lung density changes seen in all groups showed a bilateral diffuse increased pattern. but, in group III, changes were more severe in the central, peripheral and posterior portion of the lower lung. Ground glass opacity and focal patchy consolidaton seen on HRCT were found on pathologic examination to be due to alveolar cell hyperplasia and septal thickening. Consolidation was caused by alveolar edema and hemorrage. Pathologic lesions were randomly distributed in both lungs. Conclusion : One HRCT images, rat exposed to hyperoxia showed ground glass opacity, patchy consolidation and diffuse consolidation. Depending on exposure time, the pathologic findings also indicated increased lung density and a bilateral, diffuse distribution pattern, as well as alveolar cell hyperplasia and septal thickening, alveolar edema and hemorrage. HRCT may be more helpful than simple X-rays for the early detection of pulmonary oxygen toxicity.

Basement membrane patterns, gelatinase A and tissue inhibitor of metalloproteinase-2 expressions, and stromal fibrosis during the development of peripheral lung adenocarcinoma

To clarify the process and mechanisms of the development and progression of peripheral lung adenocarcinoma, we investigated the relationships among the patterns of basement membrane (BM), stromal fibrosis, and the expressions of gelatinase A and tissue inhibitor of metalloproteinases-2 (TIMP-2) in 33 lesions of atypical alveolar cell hyperplasia (AAH) and 48 lesions of lung adenocarcinoma, including 24 lesions of bronchioloalveolar carcinoma (BAC). We found that the architecture of alveolar BM was intact in all 33 AAH lesions and 11 nonsclerosing BAC lesions that formed no central scar, suggesting that these lesions are early-stage intraepithelial neoplasia. The preexistent BM of the lung was disrupted, and the BM components around the neoplastic glands were disrupted or absent in the area of the central scar of some sclerosing BAC lesions with collapse fibrosis alone (2 of 4) and in those of all of the adenocarcinoma lesions associated with desmoplastic stromal fibrosis (nine sclerosing BAC and 24 non-BAC tumors). These results suggested that, in lung adenocarcinomas, destruction of the BM was correlated with the formation of a central scar, particularly with desmoplasia. It is likely that adenocarcinomas with a central scar are advanced and invasive cancers potentially having metastatic activity. The expression of gelatinase A and TIMP-2 was associated with central scar formation as well as with destruction of the BM components. Both the neoplastic and stromal cells expressed gelatinase A and TIMP-2 and probably play a role in tumor cell invasion.