fibrin and Pneumonia

Topics: Animals; Bacterial Infections; Cecum; Colon; Disease Models, Animal; Fibrin; Ligation; Lipopolysaccharides; Mice; Pneumonia; Sepsis; Stents

Enhanced intrapulmonary fibrin deposition as a result of abnormal broncho-alveolar fibrin turnover is a hallmark of acute respiratory distress syndrome (ARDS), pneumonia and ventilator-induced lung injury (VILI), and is important to the pathogenesis of these conditions. The mechanisms that contribute to alveolar coagulopathy are localized tissue factor-mediated thrombin generation, impaired activity of natural coagulation inhibitors and depression of bronchoalveolar urokinase plasminogen activator-mediated fibrinolysis, caused by the increase of plasminogen activator inhibitors. There is an intense and bidirectional interaction between coagulation and inflammatory pathways in the bronchoalveolar compartment. Systemic or local administration of anticoagulant agents (including activated protein C, antithrombin and heparin) and profibrinolytic agents (such as plasminogen activators) attenuate pulmonary coagulopathy. Several preclinical studies show additional anti-inflammatory effects of these therapies in ARDS and pneumonia.

Topics: Animals; Anticoagulants; Fibrin; Fibrinolytic Agents; Hemostasis; Humans; Inflammation Mediators; Pneumonia; Pulmonary Alveoli; Respiratory Distress Syndrome; Ventilator-Induced Lung Injury

Acute inflammatory and chronic interstitial lung diseases are characterized by excessive and persistent fibrin deposition in the lung. Intraalveolar fibrin accumulation, observed under these conditions, arises from a leakage of plasma proteins (including fibrinogen) into the alveolar space in combination with a disbalance of alveolar haemostasis. Tissue factor in association with factor VIIa and inhibition of urokinase by plasminogen activator inhibitor-1 are major factors that are responsible for the procoagulant and antifibrinolytic state. In addition, in acute respiratory distress syndrome (ARDS) patients, factor VII-activating protease and extracellular RNA, which may be released into the extracellular milieu from damaged cells during lung injury, may contribute to fibrin formation as well. Fibrin itself can increase vascular permeability, influence the expression of inflammatory mediators and alter the migration and proliferation of various cell types. Additionally, fibrin may inactivate pulmonary surfactant and provide a matrix on which fibroblasts can migrate and produce collagen. Furthermore, cellular activities of haemostatic proteases may also contribute to proinflammatory and fibrotic processes in the lung. The application of coagulation inhibitors, like tissue factor pathway inhibitor, active site-inactivated factor VIIa, activated protein C, antithrombin, heparin or hirudin turned out to be beneficial in experimental models of acute and chronic lung injury. However, the ability of anticoagulant and profibrinolytic agents to improve clinical outcome remains to be elucidated. In the current article, the role of the alveolar coagulation and fibrinolysis systems in acute inflammatory and chronic interstitial lung diseases is discussed with regard to pathomechanisms and modalities of intervention.

Topics: Acute Disease; Animals; Anticoagulants; Blood Coagulation; Blood Coagulation Factors; Chronic Disease; Fibrin; Fibrinolysis; Fibrinolytic Agents; Humans; Lung Diseases, Interstitial; Pneumonia; Pulmonary Alveoli

Understanding mechanisms that underlie lung disorders is crucial to achieving optimum care and improved outcomes in pulmonary medicine. Extensive investigations have revealed that inflammation displays an active role in the pathogenesis of these diseases. The byproduct of these inflammatory reactions has been shown to propagate pulmonary disease in consonance with alteration in haemostatic balance. It is now apparent that the two phenomena constitute an interwoven relationship with protective but damaging effects, when dysregulated. However, the precise role of coagulation abnormalities in pulmonary pathology is still evolving. A large body of evidence suggests that an imbalance in intra-alveolar procoagulant and fibrinolytic activities occurs in a variety of lung conditions. This imbalance may even herald a number of pulmonary diseases. Its sequelae have been observed in lung parenchyma of humans and in animal models of lung inflammation. As the pathogenesis of coagulation-related lung diseases continues to be unraveled, therapeutic measures to mitigate pulmonary disease-specific coagulopathy are emerging. Current efforts are directed at depicting multifaceted molecules capable of selective but simultaneous interference with relevant aspects of the dual coagulation-fibrinolytic pathway.

Topics: Animals; Blood Coagulation; Blood Coagulation Disorders; Fibrin; Humans; Models, Biological; Pneumonia

To review the involvement of coagulation and fibrinolysis in the pathogenesis of acute lung injury during severe infection. To review the cross-talk between coagulation and inflammation that may affect this response.. Published articles on experimental and clinical studies of coagulation and fibrinolysis during infection, inflammation, acute lung injury, and evolving acute respiratory distress syndrome.. Fibrin deposition is an important feature of pulmonary infection or severe inflammation. The mechanisms that contribute to this fibrin deposition are bronchoalveolar tissue factor-mediated thrombin generation and localized depression of urokinase plasminogen activator-mediated fibrinolysis, caused by the increase of plasminogen activator inhibitors. These effects on pulmonary coagulation and fibrinolysis are regulated by various proinflammatory cytokines. Rather than being a unidirectional relationship, the interaction between inflammation and coagulation involves significant cross-talk. Coagulation and fibrinolytic proteins may have an additional role beyond fibrin turnover and inflammation, e.g., in mechanisms mediating cell recruitment and migration.

Topics: Bronchoalveolar Lavage Fluid; Cytokines; Endotoxemia; Fibrin; Fibrinolysis; Humans; Pneumonia; Respiratory Distress Syndrome; Thromboplastin

Topics: Fibrin; Humans; Lung; Lung Neoplasms; Pleura; Pneumonia

Topics: Fibrin; Fibroblasts; Humans; Lung; Pneumonia; Pulmonary Alveoli; Pulmonary Fibrosis; Signal Transduction

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) is a common clinical problem, leading to significant morbidity and mortality, and no effective pharmacotherapy exists. The problem of ARDS causing mortality became more apparent during the COVID-19 pandemic. Biotherapeutic products containing multipotent mesenchymal stromal cell (MMSC) secretome may provide a new therapeutic paradigm for human healthcare due to their immunomodulating and regenerative abilities. The content and regenerative capacity of the secretome depends on cell origin and type of cultivation (two- or three-dimensional (2D/3D)). In this study, we investigated the proteomic profile of the secretome from 2D- and 3D-cultured placental MMSC and lung fibroblasts (LFBs) and the effect of inhalation of freeze-dried secretome on survival, lung inflammation, lung tissue regeneration, fibrin deposition in a lethal ALI model in mice. We found that three inhaled administrations of freeze-dried secretome from 2D- and 3D-cultured placental MMSC and LFB protected mice from death, restored the histological structure of damaged lungs, and decreased fibrin deposition. At the same time, 3D MMSC secretome exhibited a more pronounced trend in lung recovery than 2D MMSC and LFB-derived secretome in some measures. Taking together, these studies show that inhalation of cell secretome may also be considered as a potential therapy for the management of ARDS in patients suffering from severe pneumonia, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), however, their effectiveness requires further investigation.

Topics: Acute Lung Injury; Animals; Cell Culture Techniques; COVID-19; Female; Fibrin; Humans; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Pandemics; Placenta; Pneumonia; Pregnancy; Proteomics; Respiratory Distress Syndrome; SARS-CoV-2; Secretome

Acute fibrinous and organising pneumonia (AFOP) is a rare form of interstitial lung disease. It is a pathological diagnosis sharing similarities to organising pneumonia, diffuse alveolar damage and eosinophilic pneumonia, however, is histologically distinct, characterised by intra-alveolar fibrin deposition ('fibrin balls') and associated organising pneumonia. AFOP was first described in 2002, only 150 cases have been reported since. While it has been described in association with infection, autoimmune disorders, connective tissue diseases, drugs, environmental exposures and organ transplant, it can also be idiopathic in nature. AFOP follows an acute course with potential rapid fulminant respiratory failure, or a subacute trajectory with a more favourable prognosis. Corticosteroids are commonly prescribed to induce remission. While cases of relapse of AFOP during weaning or cessation of steroids have been described, there are no published cases of remote relapse of AFOP. We describe a case of idiopathic AFOP, which recurred after 12 years of good health.

Topics: Adrenal Cortex Hormones; Chronic Disease; Fibrin; Humans; Lung Diseases, Interstitial; Pneumonia; Recurrence

Topics: Animals; Blood Coagulation; Caspases, Initiator; Cell Death; Cytokines; Fibrin; Host-Pathogen Interactions; Inflammation Mediators; Klebsiella Infections; Klebsiella pneumoniae; Lung; Mice, Inbred C57BL; Neutrophils; Pneumonia

The clinical benefit of second-generation drug-eluting stents (2nd DES) has been established, compared to first-generation drug-eluting stents (1st DES). However, pathological response after 2nd DES implantation remains unclear, particularly in the Japanese population.. Using specimens obtained by autopsy, we compared the histology between 2nd DES (41 sections) and 1st DES (38 sections) lesions within 1 year after stent implantation to evaluate early tissue reaction in Japanese patients. Stent segments were fixed with 10% buffered formalin and embedded in plastic, followed by hematoxylin-eosin and Masson's trichrome staining. Ratio of covered stent struts was calculated, and the area of fibrin deposition was morphometrically evaluated. The degree of inflammation around struts was examined semi-quantitatively (score 0-3).. The ratio of covered struts and mean fibrin area of 2nd DES were 0.69±0.05 and 658.0±173.4μm. Histopathological analysis showed advanced healing process in 2nd DES compared with 1st DES lesions. These results are consistent with clinical beneficial outcome of 2nd DES implantation.

Topics: Aged; Aneurysm, Ruptured; Colitis, Ischemic; Coronary Vessels; Drug-Eluting Stents; Everolimus; Female; Fibrin; Heart Failure; Humans; Inflammation; Japan; Male; Middle Aged; Neointima; Pancreatitis; Pneumonia; Renal Insufficiency; Risk Factors; Sepsis; Sirolimus; Treatment Outcome

In contrast to fungal dermatitis, fungal glossitis and disseminated visceral mycosis, fungal infection of the lung has so far rarely been described in reptiles. Pulmonary fungal granulomas were diagnosed histopathologically within the scope of post mortem examinations. Fragments of the 18S-internal transcribed spacer1-5.8S rDNA (SSU-ITS1-5.8S) and 28S rDNA (LSU), including domains (D)1 and D2 as well as the protein coding gene translation elongation factor 1 alpha (TEF) were used for phylogenetical analysis after isolation of the fungal pathogen by culturing. Ten reptiles, including lizards (n = 6), snakes (n = 1), crocodilians (n = 2) and tortoises (n = 1) presented with pulmonary fungal granulomas (n = 8) and fibrinous pneumonia (n = 2) caused by different non-clavicipitaceous and clavicipitaceous species of the order Hypocreales. Purpureocillium lavendulum (n = 2) and Metarhizium robertsii (n = 1) as the etiologic agents of pneumonia in reptile species are described for the first time. Fungal pulmonary granulomas caused by clavicipitaceous fungi (n = 6) were all associated with disseminated visceral mycosis as well as oral fungal granulomas (n = 4) and/or fungal dermatitis (n = 1). Differing infection routes being likely for clavicipitaceous and non-clavicipitaceous fungal pathogens. A potential zoonotic health risk should be taken into account during necropsy or lung sampling in live reptiles with pulmonary fungal granulomas, since human infections, mainly keratitis and sclerokeratitis, caused by Beauveria bassiana, Metarhizium robertsii and Purpureocillium lilacinum, have occasionally been described.

Topics: Alligators and Crocodiles; Animals; Beauveria; Boidae; DNA, Ribosomal; Fibrin; Granuloma; Humans; Hypocreales; Lizards; Lung; Metarhizium; Mycoses; Phylogeny; Pneumonia; Reptiles; Zoonoses

BACKGROUND Acute fibrinous and organizing pneumonia (AFOP) is a newly evolving rare non-infectious lung pathology, characterized by intra-alveolar fibrin balls on histology. It is often difficult to diagnose and is usually mistaken for other lung pathologies. We present an interesting case of AFOP with unusual radiologic findings and disease course. CASE REPORT A 56-year-old woman presented with a 1-day history of high-grade fever, chills, and profuse sweating. She was febrile to 101.2 degree Fahrenheit on presentation. On physical examination, she had decreased air entry in the left upper lobe of the lung. Laboratory testing showed a white cell count of 27,000 cells per microliter of blood with left shift. A chest radiograph showed a left upper lobe consolidation. Computed tomography (CT) of the chest without intravenous contrast showed advanced centrilobular emphysema and left upper lobe consolidation measuring 6.2×5.9 cm. The patient was started on antibiotics. She clinically improved and was discharged on oral antibiotics. After discharge, a trans-bronchial lung biopsy showed acute inflammatory cell infiltrate with intra-alveolar fibrin balls but no hyaline membrane formation or significant eosinophils. These findings were consistent with acute fibrinous and organizing pneumonia. However, she was subsequently lost to follow-up. CONCLUSIONS Our case adds to the literature a new and unusual finding of upper lobe infiltrates, in contrast to most cases presenting as bilateral lower lobe infiltrates. In our case, symptomatic improvement after antibiotic treatment suggests a possible role of antibiotics in management of this entity.

Topics: Chills; Female; Fever; Fibrin; Humans; Lung; Middle Aged; Pneumonia; Pulmonary Emphysema; Sweating

Topics: Anti-Bacterial Agents; Biopsy; Community-Acquired Infections; Cryptogenic Organizing Pneumonia; Diagnosis, Differential; Female; Fever; Fibrin; Glucocorticoids; Humans; Legionella pneumophila; Legionnaires' Disease; Levofloxacin; Lung; Lung Diseases, Interstitial; Middle Aged; Pneumonia; Prednisolone; Radiography; Rare Diseases; Tomography, X-Ray Computed; Treatment Outcome

Tissue factor (TF) is a transmembrane glycoprotein that plays an essential role in hemostasis by activating coagulation. TF is also expressed by monocytes/macrophages as part of the innate immune response to infections. In the current study, we determined the role of TF expressed by myeloid cells during Mycobacterium tuberculosis (M. tb) infection by using mice lacking the TF gene in myeloid cells (TF(Δ) ) and human monocyte derived macrophages (MDMs). We found that during M. tb infection, a deficiency of TF in myeloid cells was associated with reduced inducible nitric oxide synthase (iNOS) expression, enhanced arginase 1 (Arg1) expression, enhanced IL-10 production and reduced apoptosis in infected macrophages, which augmented M. tb growth. Our results demonstrate that a deficiency of TF in myeloid cells promotes M2-like phenotype in M .tb infected macrophages. A deficiency in TF expression by myeloid cells was also associated with reduced fibrin deposition and increased matrix metalloproteases (MMP)-2 and MMP-9 mediated inflammation in M. tb infected lungs. Our studies demonstrate that TF expressed by myeloid cells has newly recognized abilities to polarize macrophages and to regulate M. tb growth.

Topics: Animals; Bacteremia; Blood Coagulation; Cell Differentiation; Female; Fibrin; Host-Pathogen Interactions; Humans; Immunity, Innate; Lung; Macrophages; Mice, Inbred C57BL; Mice, Knockout; Mycobacterium tuberculosis; Pneumonia; Thromboplastin; Tuberculoma; Tuberculosis, Pulmonary

Mycobacterium tuberculosis, the causative agent of tuberculosis, drives the formation of granulomas, structures in which both immune cells and the bacterial pathogen cohabit. The most abundant cells in granulomas are macrophages, which contribute as both cells with bactericidal activity and as targets for M. tuberculosis infection and proliferation during the entire course of infection. The mechanisms and factors involved in the regulation and control of macrophage microenvironment-specific polarization and plasticity are not well understood, as some granulomas are able to control bacteria growth and others fail to do so, permitting bacterial spread. In this issue of the European Journal of Immunology, Venkatasubramanian et al. [Eur. J. Immunol. 2016. 46: 464-479] show that mice lacking the tissue factor gene in myeloid cells have augmented M. tuberculosis growth and increased inflammation in the lungs. This suggests that tissue factor, an initiator of coagulation, is important for the generation of fibrin, which supports granuloma formation. This article demonstrates for the first time the involvement of tissue factor in inducing effective immunity against M. tuberculosis, and sheds new lights on the complex interplay between host inflammatory response, the coagulation system, and the control of M. tuberculosis infection.

Topics: Animals; Bacteremia; Blood Coagulation; Cell Differentiation; Fibrin; Host-Pathogen Interactions; Humans; Immunity, Innate; Lung; Macrophages; Mice; Mice, Knockout; Mycobacterium tuberculosis; Pneumonia; Thromboplastin; Tuberculoma; Tuberculosis, Pulmonary

This study examined the clinical significance of intra-alveolar fibrin deposition (IAFD) in transbronchial lung biopsy specimens obtained from patients with organizing pneumonia.. Pathological reports of transbronchial lung biopsies performed between 2004 and 2012 were reviewed to identify cases of intra-alveolar organization with or without fibrin deposition. Clinical charts, computed tomography images, and transbronchial lung biopsy specimens from these cases were examined retrospectively. Diagnosis of organizing pneumonia was reevaluated based upon the consensus of a respiratory physician, a radiologist, and a pathologist.. Transbronchial lung biopsy results of the reviewed patients with organizing pneumonia found seven patients who had IAFD, and 34 who did not. Seven patients' conditions were associated with collagen vascular disease (CVD), and 34 were cryptogenic. IAFD was significantly associated with high C-reactive protein (CRP) values (>5 mg/dl) (p = 0.0012) and underlying CVD (p = 0.0099). Multivariate analysis revealed that IAFD was independently associated with high CRP values (p = 0.0184). Three of 31 patients and six of 27 patients experienced a relapse of organizing pneumonia within 6 months and 1 year, respectively. IAFD (p = 0.0044) and high CRP values (p = 0.0207) were significantly related to relapse within 6 months, while only CRP was significantly related to relapse within 1 year (p = 0.0007).. In patients with organizing pneumonia, IAFD was significantly associated with high CRP values. High CRP values and/or IAFD predicted relapse of organizing pneumonia within 6 months to 1 year.

Topics: Aged; Biopsy; C-Reactive Protein; Collagen Diseases; Female; Fibrin; Humans; Male; Pneumonia; Pulmonary Alveoli; Radiography; Recurrence; Retrospective Studies; Vascular Diseases

Intervening in angiotensin (Ang)-II type 2 receptor (AT2) signaling may have therapeutic potential for bronchopulmonary dysplasia (BPD) by attenuating lung inflammation and preventing arterial hypertension (PAH)-induced right ventricular hypertrophy (RVH). We first investigated the role of AT2 inhibition with PD123319 (0.5 and 2 mg·kg(-1)·day(-1)) on the beneficial effect of AT2 agonist LP2-3 (5 μg/kg twice a day) on RVH in newborn rats with hyperoxia-induced BPD. Next we determined the cardiopulmonary effects of PD123319 (0.1 mg·kg(-1)·day(-1)) in two models: early treatment during continuous exposure to hyperoxia for 10 days and late treatment starting on day 6 in rat pups exposed postnatally to hyperoxia for 9 days, followed by a 9-day recovery period in room air. Parameters investigated included lung and heart histopathology, fibrin deposition, vascular leakage, and differential mRNA expression. Ten days of coadministration of LP2-3 and PD123319 abolished the beneficial effects of LP2-3 on RVH in experimental BPD. In the early treatment model PD123319 attenuated cardiopulmonary injury by reducing alveolar septal thickness, pulmonary influx of inflammatory cells, including macrophages and neutrophils, medial wall thickness of small arterioles, and extravascular collagen III deposition, and by preventing RVH. In the late treatment model PD123319 diminished PAH and RVH, demonstrating that PAH is reversible in the neonatal period. At high concentrations PD123319 blocks the beneficial effects of the AT2-agonist LP2-3 on RVH. At low concentrations PD123319 attenuates cardiopulmonary injury by reducing pulmonary inflammation and fibrosis and preventing PAH-induced RVH but does not affect alveolar and vascular development in newborn rats with experimental BPD.

Topics: Angiotensin II Type 2 Receptor Blockers; Animals; Animals, Newborn; Bronchopulmonary Dysplasia; Fibrin; Heart Injuries; Hyperoxia; Hypertrophy, Right Ventricular; Imidazoles; Ligands; Lung Injury; Pneumonia; Pulmonary Alveoli; Pyridines; Rats; Rats, Wistar; Receptor, Angiotensin, Type 2

A 50-year-old man was treated with trimethoprim-sulfamethoxazole (TMP-SMX) for acute arthritis of his right big toe. Within a few days, he developed dyspnoea, hypoxaemia and diffuse pulmonary infiltrates. Symptoms improved with discontinuation of the antibiotic but worsened again with its reintroduction. An open lung biopsy was performed. We describe the workup performed and the factors that pointed to a final diagnosis of TMP-SMX-related pulmonary toxicity in the form of acute fibrinous organising pneumonia.

Topics: Alveolar Epithelial Cells; Anti-Bacterial Agents; Arthritis; Biopsy; Fibrin; Humans; Lung; Male; Middle Aged; Pneumonia; Trimethoprim, Sulfamethoxazole Drug Combination

Topics: Female; Fibrin; Headache; Humans; Middle Aged; Pneumonia; Respiratory Insufficiency

Exposure to ambient particulate matter (PM) air pollution has been reported to trigger inflammation and thrombosis. However, molecular mechanisms underlying the modulation of coagulation pathways in PM-induced thrombosis remain largely unknown. We report here that Sirt1, a member of class III histone deacetylase, controls lung inflammation and coagulation after PM exposure. Sirt1 knock-out mice exhibited aggravated lung vascular leakage and inflammation after PM exposure, which was correlated with increased NF-κB acetylation and activation. Furthermore, Sirt1 knock-out mice were highly susceptible to PM-induced lung coagulation as demonstrated by increased fibrin formation. The increased fibrin formation was associated with reduced tissue factor pathway inhibitor (TFPI) expression and increased plasminogen activator inhibitor-1 (PAI-1) activity in the lungs, thus favoring elevated coagulation and disrupted fibrinolysis responses. Thrombomodulin (TM), a central player of the anticoagulant protein C system, is regulated by Kruppel-like factor 2 (KLF2) at the transcriptional level. Our data show that PM exposure led to decreased lung KLF2 and TM expression in wild-type mice, and lung KLF2 and TM protein levels were further decreased in Sirt1 knock-out mice. Importantly, Sirt1 gene delivery inhibited TM and KLF2 down-regulation and reduced lung coagulation after PM exposure. Collectively, our studies indicate that Sirt1 functions as a suppressor of coagulation after particulate matter exposure.

Topics: Air Pollution; Animals; Capillary Permeability; Down-Regulation; Endothelial Cells; Female; Fibrin; Immunoblotting; Kruppel-Like Transcription Factors; Lipoproteins; Lung; Lung Injury; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Microscopy, Fluorescence; Particulate Matter; Plasminogen Activator Inhibitor 1; Pneumonia; Sirtuin 1; Thrombomodulin

Exposure of human populations to ambient particulate matter (PM) air pollution significantly contributes to the mortality attributable to ischemic cardiovascular events. We reported that mice treated with intratracheally instilled PM develop a prothrombotic state that requires the release of IL-6 by alveolar macrophages. We sought to determine whether exposure of mice to PM increases the levels of PAI-1, a major regulator of thrombolysis, via a similar or distinct mechanism.. Adult, male C57BL/6 and IL-6 knock out (IL-6(-/-)) mice were exposed to either concentrated ambient PM less than 2.5 µm (CAPs) or filtered air 8 hours daily for 3 days or were exposed to either urban particulate matter or PBS via intratracheal instillation and examined 24 hours later. Exposure to CAPs or urban PM resulted in the IL-6 dependent activation of coagulation in the lung and systemically. PAI-1 mRNA and protein levels were higher in the lung and adipose tissue of mice treated with CAPs or PM compared with filtered air or PBS controls. The increase in PAI-1 was similar in wild-type and IL-6(-/-) mice but was absent in mice treated with etanercept, a TNF-α inhibitor. Treatment with etanercept did not prevent the PM-induced tendency toward thrombus formation.. Mice exposed to inhaled PM exhibited a TNF-α-dependent increase in PAI-1 and an IL-6-dependent activation of coagulation. These results suggest that multiple mechanisms link PM-induced lung inflammation with the development of a prothrombotic state.

Topics: Adipose Tissue, White; Animals; Blood Coagulation; Cell Line, Tumor; Cities; Fibrin; Humans; Inhalation Exposure; Interleukin-6; Lung; Mice; Particle Size; Particulate Matter; Plasminogen Activator Inhibitor 1; Pneumonia; Transcription, Genetic; Tumor Necrosis Factor-alpha

The urokinase plasminogen activator receptor (uPAR) has emerged as a potential regulator of cell adhesion, cell migration, proliferation, differentiation, and cell survival in multiple physiologic and pathologic contexts. The urokinase plasminogen activator (uPA) was the first identified ligand for uPAR, but elucidation of the specific functions of the uPA-uPAR interaction in vivo has been difficult because uPA has important physiologic functions that are independent of binding to uPAR and because uPAR engages multiple ligands. Here, we developed a new mouse strain (Plau(GFDhu/GFDhu)) in which the interaction between endogenous uPA and uPAR is selectively abrogated, whereas other functions of both the protease and its receptor are retained. Specifically, we introduced 4 amino acid substitutions into the growth factor domain (GFD) of uPA that abrogate uPAR binding while preserving the overall structure of the domain. Analysis of Plau(GFDhu/GFDhu) mice revealed an unanticipated role of the uPA-uPAR interaction in suppressing inflammation secondary to fibrin deposition. In contrast, leukocyte recruitment and tissue regeneration were unaffected by the loss of uPA binding to uPAR. This study identifies a principal in vivo role of the uPA-uPAR interaction in cell-associated fibrinolysis critical for suppression of fibrin accumulation and fibrin-associated inflammation and provides a valuable model for further exploration of this multifunctional receptor.

Topics: Animals; Apoptosis; Blotting, Western; Cell Proliferation; Disease Models, Animal; Female; Fibrin; Flow Cytometry; Fluorescent Antibody Technique; Humans; Immunoenzyme Techniques; Inflammation; Liver; Lung Injury; Macrophages, Peritoneal; Male; Mice; Mice, Inbred C57BL; Pneumonia; Receptors, Urokinase Plasminogen Activator; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Skin Diseases; Survival Rate; Urokinase-Type Plasminogen Activator; Wound Healing

Platelet activation contributes to microvascular thrombosis and organ failure in systemic inflammation. We tested the hypothesis whether anti-platelet drugs might favourably affect outcome in patients at risk for organ failure as well as in a mouse model of endotoxin shock. Two hundred twenty-four consecutive patients who were admitted for community acquired pneumonia over a time period of 5 years to a University Hospital were enrolled; about 20% of whom received anti-platelet drugs (acetylsalicylic acid, thienopyridines) for secondary prevention of cardiovascular disease. Patients with anti-platelet drugs were about 12 years old but did not differ in SOFA score and routine laboratory parameters at admission. Logistic regression and 2 x 2 table analysis in age-matched subgroups indicated that anti-platelet drugs may reduce the need of intensive care treatment (odds ratio (OR) 0.32 [95% confidential interval: 0.10-1.00] and 0.19 [0.04-0.87], respectively). In age-matched subgroups, the use of anti-platelet drugs was also associated with a shorter stay in hospital (13.9 +/- 6.2 vs. 18.2 +/- 10.2 days; p < 0.02). In the animal model Balb/c mice were pre-treated with clopidogrel (added to drinking water) for 4 days prior to intraperitoneal (i.p.) administration of endotoxin (lipopolsaccharide (LPS) from Escherichia coli 0111:B4). Within the first 48 hours after LPS there were no differences between clopidogrel and control animals (n = 26 each) in macro-haemodynamics. However, clopidogrel abolished the LPS-induced drop in platelet count and reduced fibrin deposition in lung tissue. Using DNA microarray technology, we could show that clopidogrel suppressed endotoxin-induced up-regulation of inflammation-relevant genes, including arachidonate-5-lipoxygenase activating protein and leukotriene B4 receptor 1. According to our data a possible benefit of anti-platelet drugs in patients on risk for systemic inflammation and organ failure should be tested in a prospective trial.

Topics: Adult; Aged; Animals; Cell Line; Clopidogrel; Female; Fibrin; Gene Expression Profiling; Hemodynamics; Humans; Infections; Intensive Care Units; Length of Stay; Leukocytes; Lung; Male; Mice; Mice, Inbred BALB C; Middle Aged; Oligonucleotide Array Sequence Analysis; Platelet Activation; Platelet Aggregation Inhibitors; Pneumonia; Retrospective Studies; Shock, Septic; Ticlopidine

Phosphodiesterase-5 inhibition with sildenafil has been used to treat severe pulmonary hypertension and bronchopulmonary dysplasia (BPD), a chronic lung disease in very preterm infants who were mechanically ventilated for respiratory distress syndrome.. Sildenafil treatment was investigated in 2 models of experimental BPD: a lethal neonatal model, in which rat pups were continuously exposed to hyperoxia and treated daily with sildenafil (50-150 mg/kg body weight/day; injected subcutaneously) and a neonatal lung injury-recovery model in which rat pups were exposed to hyperoxia for 9 days, followed by 9 days of recovery in room air and started sildenafil treatment on day 6 of hyperoxia exposure. Parameters investigated include survival, histopathology, fibrin deposition, alveolar vascular leakage, right ventricular hypertrophy, and differential mRNA expression in lung and heart tissue.. Prophylactic treatment with an optimal dose of sildenafil (2 x 50 mg/kg/day) significantly increased lung cGMP levels, prolonged median survival, reduced fibrin deposition, total protein content in bronchoalveolar lavage fluid, inflammation and septum thickness. Treatment with sildenafil partially corrected the differential mRNA expression of amphiregulin, plasminogen activator inhibitor-1, fibroblast growth factor receptor-4 and vascular endothelial growth factor receptor-2 in the lung and of brain and c-type natriuretic peptides and the natriuretic peptide receptors NPR-A, -B, and -C in the right ventricle. In the lethal and injury-recovery model we demonstrated improved alveolarization and angiogenesis by attenuating mean linear intercept and arteriolar wall thickness and increasing pulmonary blood vessel density, and right ventricular hypertrophy (RVH).. Sildenafil treatment, started simultaneously with exposure to hyperoxia after birth, prolongs survival, increases pulmonary cGMP levels, reduces the pulmonary inflammatory response, fibrin deposition and RVH, and stimulates alveolarization. Initiation of sildenafil treatment after hyperoxic lung injury and continued during room air recovery improves alveolarization and restores pulmonary angiogenesis and RVH in experimental BPD.

Topics: Animals; Animals, Newborn; Disease Models, Animal; Fibrin; Humans; Hyperoxia; Hypertrophy, Right Ventricular; Lung Injury; Phosphodiesterase Inhibitors; Piperazines; Pneumonia; Purines; Rats; Rats, Wistar; Sildenafil Citrate; Sulfones; Survival Analysis; Survival Rate; Treatment Outcome

Administration of inhaled nitric oxide (iNO) is a potential therapeutic strategy to prevent bronchopulmonary dysplasia (BPD) in premature newborns with respiratory distress syndrome. We evaluated this approach in a rat model, in which premature pups were exposed to room air, hyperoxia, or a combination of hyperoxia and NO (8.5 and 17 ppm). We investigated the anti-inflammatory effects of prolonged iNO therapy by studying survival, histopathology, fibrin deposition, and differential mRNA expression (real-time RT-PCR) of key genes involved in the development of BPD. iNO therapy prolonged median survival 1.5 days (P = 0.0003), reduced fibrin deposition in a dosage-dependent way up to 4.3-fold (P < 0.001), improved alveolar development by reducing septal thickness, and reduced the influx of leukocytes. Analysis of mRNA expression revealed an iNO-induced downregulation of genes involved in inflammation (IL-6, cytokine-induced neutrophilic chemoattractant-1, and amphiregulin), coagulation, fibrinolysis (plasminogen activator inhibitor 1 and urokinase-type plasminogen activator receptor), cell cycle regulation (p21), and an upregulation of fibroblast growth factor receptor-4 (alveolar formation). We conclude that iNO therapy improves lung pathology and prolongs survival by reducing septum thickness, inhibiting inflammation, and reducing alveolar fibrin deposition in premature rat pups with neonatal hyperoxic lung injury.

Topics: Administration, Inhalation; Animals; Animals, Newborn; Antioxidants; Bronchoalveolar Lavage Fluid; Cell Cycle; Fibrin; Fibrinolysis; Gene Expression Regulation; Lung; Lung Diseases; Nitric Oxide; Pneumonia; Proteins; Pulmonary Alveoli; Rats; Rats, Wistar; RNA, Messenger; Signal Transduction; Survival Analysis

Topics: Dideoxynucleosides; Drug Hypersensitivity; Female; Fibrin; HIV Infections; Humans; Lung; Middle Aged; Pneumonia; Reverse Transcriptase Inhibitors

Topics: Collagen Diseases; Fibrin; Humans; Lung; Lung Diseases, Interstitial; Male; Middle Aged; Pneumonia; Pulmonary Alveoli; Vascular Diseases

Topics: Fibrin; Fibrinolytic Agents; Humans; Lung; Pneumonia; Pulmonary Fibrosis; Respiratory Distress Syndrome; Thrombosis; Time Factors

Fibrin deposition is a hallmark of pneumonia. To determine the kinetics of alterations in local coagulation and fibrinolysis in relation to ventilator associated pneumonia (VAP), a single centre prospective study of serial changes in pulmonary and systemic thrombin generation and fibrinolytic activity was conducted in patients at risk for VAP.. Non-directed bronchial lavage (NBL) was performed on alternate days in patients expected to require mechanical ventilation for more than 5 days. A total of 28 patients were studied, nine of whom developed VAP.. In patients who developed VAP a significant increase in thrombin generation was observed in the airways, as reflected by a rise in the levels of thrombin-antithrombin complexes in NBL fluid accompanied by increases in soluble tissue factor and factor VIIa concentrations. The diagnosis of VAP was preceded by a decrease in fibrinolytic activity in NBL fluid. Indeed, before VAP was diagnosed clinically, plasminogen activator activity levels in NBL fluid gradually declined, which appeared to be caused by a sharp increase in NBL fluid levels of plasminogen activator inhibitor 1.. VAP is characterised by a shift in the local haemostatic balance to the procoagulant side, which precedes the clinical diagnosis of VAP.

Topics: Blood Coagulation; Female; Fibrin; Fibrinolysis; Humans; Male; Middle Aged; Pneumonia; Prospective Studies; Respiration, Artificial

Severe infection is associated with profound alterations in the systemic haemostatic balance, with activation of coagulation and suppressed fibrinolysis. Within the alveolar compartment, similar disturbances have been described during pulmonary inflammation. The current authors investigated whether local haemostasis was influenced during ventilator-associated pneumonia (VAP). In five patients with unilateral VAP, bronchoalveolar lavage fluid (BALF) was obtained from both the infected site (as identified on chest radiograph) and the contralateral noninfected lung (with no clinical or radiographic abnormalities). Markers for coagulation and fibrinolysis were compared between infected and noninfected lungs. A total of 10 healthy volunteers and 10 mechanically ventilated patients without pneumonia served as controls. Strong activation of coagulation (high levels of thrombin-antithrombin complexes, soluble tissue factor and factor VIIa) was detected in BALF from infected lungs, compared with that from noninfected lungs and controls. Furthermore, in infected lungs, fibrinolysis was depressed, with high levels of plasminogen activator inhibitor type 1. In conclusion, ventilator-associated pneumonia is characterised by a hypercoagulant state at the site of infection.

Topics: Adult; Aged; Aged, 80 and over; Antithrombin III; Bronchoalveolar Lavage Fluid; Factor VIIa; Female; Fibrin; Fibrinolysis; Hemostasis; Humans; Lung; Male; Middle Aged; Peptide Hydrolases; Plasminogen Activator Inhibitor 1; Pneumonia; Ventilators, Mechanical

Thrombomodulin (TM) plays an important role in anticoagulation by forming a complex with thrombin, which subsequently activates protein C. TM is inactivated and downregulated by inflammatory cell mediators. This study examined whether bronchopneumonia is associated with changes in TM immunoreactivity, and whether a decrease in TM is accompanied by evidence of hypercoagulability, i.e. local deposition of fibrin. Double antibody staining for TM and fibrin was performed on lung tissue sections from patients who had died of pneumonia and from patients who had died rapidly, secondary to trauma. Inflammatory changes were assessed histologically and immunohistochemically using antibodies against interleukin-1alpha, tumor necrosis factor-alpha, and myeloperoxidase. Areas with bronchopneumonia exhibited markedly decreased endothelial TM staining of alveolar walls and small vessels. These changes were associated with prominent fibrin immunoreactivity. Some areas exhibited mild to moderate inflammation with little fibrin deposition and variable amounts of TM in adjacent vessels. This study is the first to relate changes of TM immunoreactivity levels to fibrin deposition in a human disease process. These data may have implications for pulmonary pathophysiology in patients with bronchopneumonia.

Topics: Cytokines; Endothelium, Vascular; Fibrin; Humans; Image Processing, Computer-Assisted; Immunohistochemistry; Lung; Pneumonia; Thrombomodulin

A 74-year-old female developed pneumonia following herpes simplex encephalitis. Her white blood cell counts reached 28,400/microliters, about 90% of which consisted of granulocytes. The polymorphonuclear (PMN) elastase/alpha 1-antitrypsin complex levels increased and reached the maximum of 5,019 ng/ml, indicating the release of a large amount of elastase derived from the granulocytes. The mechanism of PMN elastase release was most likely to be granulocyte destruction associated with phagocytosis. The cleavage of fibrinogen and fibrin by PMN elastase, independent of plasmin, was indicated by the presence of the fragments in immunoprecipitated plasma from the patient corresponding to elastase-induced FDP D and DD fragments and the absence of fragments corresponding to plasmin-induced FDP D and DD fragments on SDS-PAGE. These findings suggested that the large amount of PMN elastase released from the excessive numbers of granulocytes in this patient with herpes simplex encephalitis and pneumonia, induced the cleavage of fibrinogen and fibrin without the participation of plasmin.

Topics: Aged; Encephalitis, Viral; Female; Fibrin; Fibrinogen; Herpes Simplex; Humans; Opportunistic Infections; Pancreatic Elastase; Pneumonia

Clinical and pathological studies on cryptogenic organizing pneumonitis (COP) were performed in 19 cases diagnosed with transbronchial lung biopsy (TBLB). All patients suffered from fever and several respiratory symptoms. Laboratory data showed increases in erythrocyte sedimentation rate, positivity for C-reactive protein, negative tuberculin reactions and increases in complement level. Pathological findings demonstrated that there were two kinds of organizing processes. Fourteen of the 19 cases were treated with prednisolone, and two cases were observed without administration. The remaining three cases could not be followed up after therapy. In 11 of the 16 cases, abnormal shadows in chest X-ray disappeared, but remained present in five cases. As for the relationship between pathological findings and shadows in chest X-ray, Masson bodies without fibrin were observed in the 11 cases which were without shadows on X-ray, but Masson bodies containing or related to fibrin were observed in the five cases in which abnormal shadows remained. These results suggest that there are two types of organizing process in COP. Type I is an unexplained organizing process in which fibrin is not present or involved. It responds well to steroids and the prognosis is favourable. Type II is an organizing process which involves fibrin, and the character of the fibroblast-like cells is very similar to that of myofibroblasts. Type II organizing process responds poorly to steroids. Both processes can be notified relatively easily, even by TBLB tissues.

Topics: Adult; Aged; Aged, 80 and over; Female; Fibrin; Fibroblasts; Humans; Male; Middle Aged; Pneumonia; Prednisolone; Prognosis; Pulmonary Alveoli

Clinical and pathological studies on organizing pneumonia (OP) were performed in 16 cases diagnosed by transbronchial lung biopsy (TBLB). All patients were elderly and poorly-nourished with underlying disease, and suffered from fever and various respiratory symptoms. Results of laboratory studies in these cases were positive for C-reactive protein, negative for tuberculin reaction and showed high complement levels. Pathological findings demonstrated that there were two kinds of organizing process classified according to whether fibrin exudation was detected in Masson bodies or not. Twelve of the 16 cases were treated with prednisolone, and two cases were observed without administration. In nine of the 16 cases, abnormal shadows in chest X-ray disappeared, although abnormal shadows remained in five. Regarding the relationship between pathological findings and shadows in chest X-ray, Masson bodies without fibrin were observed in nine cases in which abnormal shadows in chest X-ray disappeared, but Masson bodies containing fibrin were observed in five cases in which abnormal shadows remained. These results suggest that there are two kinds of organizing process in OP. Steroid therapy tends to be ineffective in OP demonstrating organization containing fibrin caused probably by infection. However, prednisolone is effective in the OP associated with a fibrosing process, similar to idiopathic BOOP, without or with unrelated fibrin exudation of unknown origin.

Topics: Adult; Aged; Aged, 80 and over; Biopsy; Female; Fibrin; Humans; Lung; Male; Middle Aged; Pneumonia

Topics: Acute Disease; Animals; Dog Diseases; Dogs; Female; Fibrin; Hemoptysis; Male; Nocardia asteroides; Nocardia Infections; Pneumonia

The potential importance of pleural fibrin deposition in the pathogenesis of pleural injury is supported by both clinical and experimental observations. We hypothesized that the local equilibrium between procoagulant and fibrinolytic activities is disrupted to favor fibrin deposition in exudative pleuritis. To test this hypothesis, we characterized procoagulant and fibrinolytic activities in pleural exudates from patients with pneumonia, lung cancer, or empyema and transudates from patients with congestive heart failure. Procoagulant activity was generally increased in exudative processes and was due mainly to tissue factor. All effusions contained antithrombin III and inhibited factor Xa and thrombin, but endogenous prothrombinase or thrombin activities were variably detected. Pleural fluid fibrinolytic activity was increased in congestive heart failure and was due to both tissue plasminogen activator and urokinase. Depressed fibrinolytic activity was found in pleural exudates despite increased concentrations of plasminogen, mainly glu-1-plasminogen, and was due to inhibition of plasminogen activation by plasminogen activator inhibitors 1 and 2 and of plasmin, in part by alpha 2-antiplasmin. Concentrations of PAI-1 in exudative pleural fluids were increased up to 913-fold, compared with normal pooled plasma. Exudative pleural effusions are characterized by increased procoagulant and depressed fibrinolytic activity, favoring fibrin deposition in the pleural space. The balance of these activities is reversed and favors fibrin clearance in congestive heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Blood Coagulation; Blood Coagulation Factors; Empyema; Fibrin; Fibrinolysis; Heart Failure; Humans; Pleura; Pleural Effusion; Pleural Effusion, Malignant; Pneumonia

The mean levels of fibrinopeptide A (FPA), thrombin-antithrombin complex (TAT), and soluble fibrin (tPA method) in cancer patients (n = 32) were intermediate between those of patients with cerebral infarction and pancreatitis who had the most abnormal results and patients with myocardial infarction and pneumonia who had the least abnormal results. Patients with disseminated malignancies (n = 16) had significantly higher mean levels of FPA (10.6 vs. 5.3 nmol/l) and TAT (11.0 vs. 4.4 pmol/l) than patients with limited malignancies (n = 16). The difference in soluble fibrin (fibrin monomer, FM; 22.1 vs. 18.0 nmol/l) was not significant. The values of FPA, FM, and TAT in the patient population correlated significantly. There was a negative correlation between the level of antithrombin and test results for FPA (-0.69), FM (-0.48), and TAT (-0.38) in the cancer patients. Even cancer patients with locally limited disease may have elevated FPA, FM, and TAT test results, indicating a state of definite hypercoagulation.

Topics: Acute Disease; Adult; Aged; Aged, 80 and over; Antithrombin III; Blood Coagulation Disorders; Blood Coagulation Tests; Cerebral Infarction; Female; Fibrin; Fibrinopeptide A; Humans; Male; Middle Aged; Myocardial Infarction; Neoplasms; Pancreatitis; Peptide Hydrolases; Pneumonia; Predictive Value of Tests; Reference Values

Idiopathic bronchiolitis obliterans-organizing pneumonia (BOOP) is characterized by air space fibrosis of unknown origin. Clinical resolution under steroid treatment suggests the removal of the fibrotic lesion. Open lung biopsies of four patients with idiopathic BOOP were studied by immunochemistry and electron microscopy. Three distinct cell-matrix patterns of intra-alveolar bud were found to represent the sequential evolution of the fibrotic process: fibrinoid inflammatory cell clusters in which immunoglobulins and procoagulant factors (fibrinogen, factors VII and X) were identified; fibroinflammatory buds in which desmin-containing fibroblasts were observed migrating, proliferating, and secreting matrix proteins; fibrotic buds in which myofibroblasts organized a loose connective matrix predominantly composed of fibronectin and type III collagen. Extending forms of fibrotic buds may join contiguous alveoli. Fibrotic bud remodeling ability is correlated to the nature and organization of the matrix components but the factors permitting intra-alveolar matrix degradation must be characterized.

Topics: Blood Coagulation Factors; Bronchiolitis Obliterans; Collagen; Fibrin; Fibrinogen; Fibronectins; Humans; Immunohistochemistry; Pneumonia; Pulmonary Alveoli; Pulmonary Fibrosis

We performed bronchoalveolar lavage (BAL) 0.5 to 24 h after thrombin-induced pulmonary microembolization in spontaneously breathing sheep to examine the inflammatory events that occur after pulmonary intravascular coagulation. Neutrophil alveolitis was evident as early as 0.5 h after microembolization and was maximal at 4 h (4.9 +/- 1.5% neutrophils of total BAL cells at baseline versus 26.2 +/- 2.8% at 4 h post-thrombin). Neutrophils obtained both at baseline (isolated from peripheral blood) and at 0.5 to 24 h after thrombin (isolated from BAL) did not demonstrate significant basal production of superoxide anion (O2-) and produced similar amounts of O2- upon challenge with phorbol myristate acetate (PMA) 200 micrograms/ml. The basal O2- production by alveolar macrophages was also not increased. However, alveolar macrophages recovered after fibrin microembolization produced greater amounts of O2- (29.1 +/- 6.3 nm O2-/10(6) cells at 0.5 h) after challenge with PMA compared with alveolar macrophages recovered prior to embolization (10.6 +/- 1.6 nm O2-/10(6) cells baseline), suggesting that thrombin-induced microembolization primes alveolar macrophages and enhances their O2- generation. Neutrophil chemotactic activity was detected in BAL fluid at 0.5 h post-microembolization and reached a peak level at 2 h. Alveolar macrophages were a source of the chemotactic activity since conditioned medium obtained from 2-h post-thrombin macrophages induced neutrophil chemotaxis, whereas baseline cells did not. The addition of the thrombin to macrophages did not result in the generation of chemotactic activity from baseline macrophages, indicating that macrophages were activated during the process of intravascular coagulation rather than by thrombin per se. Post-thrombin BAL fluid also stimulated O2- generation from sheep neutrophils.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Albumins; Animals; Bronchoalveolar Lavage Fluid; Cell Count; Fibrin; Macrophages; Neutrophils; Pneumonia; Pulmonary Embolism; Sheep; Superoxides

Parenchymal fibrin deposition is well recognized in many forms of acute lung injury. Proteins derived from the actions of the coagulation and fibrinolytic systems may potentiate these inflammatory reactions as well as influence the subsequent repair process. However, the factors regulating fibrin formation and dissolution in acute pneumonitis have not been defined. In this study, we characterized the procoagulant (PC) and fibrinolytic activities simultaneously present in the alveolar space during the course of acute lung injury induced in rabbits by an intravenous injection of phorbol myristate acetate (PMA). Within 6 h of PMA injection, this injury was characterized histologically by extensive intra-alveolar fibrin formation and marked accumulation in pulmonary parenchyma of intravenously administered 125I-fibrinogen. Clearance of fibrin ensued over the remainder of the 72-h study period. Normal BAL fluid contained high levels of procoagulant activity which did not vary after the onset of inflammation. The procoagulant activity was attributed to particle-bound tissue thromboplastin as well as other factors of the extrinsic coagulation pathway. There were low levels of plasminogen activator (PA) activity in normal BAL fluid, but the mean activity increased 9.3-fold over control values by 12 h after PMA injection (p less than 0.01). When plasminogen activator activity in BAL fluid was referenced to the concomitant procoagulant activity, this ratio (PA/PC) increased 17.8-fold over controls, peaking 24 h after PMA injection (p less than 0.01). The levels of both procoagulant and plasminogen activator activities associated with alveolar macrophages were stable during the study period. Compared to alveolar macrophages, granulocytes expressed similar levels of plasminogen activator but negligible procoagulant activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Blood Coagulation Factors; Fibrin; Fibrinolysis; Leukocytes; Macrophages; Male; Plasminogen Activators; Pneumonia; Pulmonary Alveoli; Rabbits; Tetradecanoylphorbol Acetate

The histopathologic events in the developing acute pulmonary inflammatory reaction to inhaled particles of Yttrium 90 are detailed. In animals that died or were sacrificed during the first year after inhalation exposure, microscopic findings of acute inflammation predominated and included vascular congestion; stasis, focal hemorrhage; edema; various inflammatory cell infiltrates; cytolysis and desquamation of bronchiolar and alveolar epithelium followed by regeneration; vascular injury and repair; and the eventual development of pulmonary fibrosis. Accumulation of alveolar fibrin deposits was an additional characteristic, though not a constant feature of the early stages of radiation pneumonitis. In addition to the direct effects of radiation on pulmonary cell populations, the histopathologic findings were suggestive of diverse activation of various cellular and humoral mediation systems in their pathogenesis. The potential interrelationships of systems responsible for increased vascular permeability, coagulation and fibrinolysis, chemotaxis, and direct cellular injury were discussed and related to the pathogenesis of the microscopic findings characteristic of early pulmonary radiation injury.

Topics: Aerosols; Animals; Capillary Permeability; Environmental Exposure; Fibrin; Inflammation; Lung; Pneumonia; Pulmonary Alveoli; Radiation Injuries, Experimental; Yttrium Radioisotopes

Topics: Adolescent; Adult; Aged; Candidiasis; Child; Child, Preschool; Deglutition Disorders; Epithelial Cells; Esophagitis; Female; Fibrin; Heart; Herpes Simplex; Humans; Lung; Male; Middle Aged; Necrosis; Pneumonia; Respiratory Tract Infections; Simplexvirus; Trachea

Topics: Adult; Aged; Autoimmune Diseases; Biopsy, Needle; Bronchiectasis; Chronic Disease; Empyema; Female; Fibrin; Fibrinogen; Fluorescent Antibody Technique; Humans; Kidney; Kidney Diseases; Lung; Lung Diseases; Male; Microscopy, Electron; Middle Aged; Phagocytosis; Pleural Diseases; Pneumonia

Topics: Amniotic Fluid; Animals; Bronchi; Cesarean Section; Enterococcus faecalis; Escherichia coli; Extraembryonic Membranes; Exudates and Transudates; Female; Fetal Diseases; Fibrin; Gastric Juice; Gestational Age; Inflammation; Injections; Ink; Klebsiella pneumoniae; Leukocytes; Lung; Meconium; Pneumonia; Pregnancy; Pulmonary Alveoli; Rabbits; Staphylococcus

Topics: Animals; Capillaries; Epithelium; Female; Fibrin; Lipidoses; Lung; Lymphatic System; Macrophages; Male; Necrosis; Phagocytosis; Pneumonia; Pulmonary Alveoli; Pulmonary Edema; Salmonella; Salmonella Infections; Salmonella Infections, Animal; Swine; Time Factors; Toxins, Biological

Topics: Adolescent; Adult; Arteries; Azaserine; Azathioprine; Basement Membrane; Creatine; Cryptococcosis; Dactinomycin; Epithelial Cells; Female; Fibrin; Fluorescent Antibody Technique; Follow-Up Studies; Graft Rejection; Hematuria; Humans; Immunoglobulin G; Immunoglobulin M; Immunosuppressive Agents; Kidney Failure, Chronic; Kidney Glomerulus; Kidney Papillary Necrosis; Kidney Transplantation; Male; Mercaptopurine; Pneumonia; Prednisone; Proteinuria; Thrombosis; Transplantation Immunology; Transplantation, Homologous

Topics: Animals; Antigens; Blood Vessels; Bronchi; Fibrin; Fluorescent Antibody Technique; gamma-Globulins; Lung; Mice; Orthomyxoviridae; Orthomyxoviridae Infections; Pneumonia; Pulmonary Artery; Pulmonary Veins; Time Factors

Topics: Autopsy; Bronchitis; Burns; Embolism, Fat; Fibrin; Humans; Lung; Pneumonia; Pulmonary Alveoli; Pulmonary Artery; Pulmonary Embolism; Pulmonary Veins; Thoracic Injuries

Topics: Adult; Afibrinogenemia; Aminocaproates; Blood Transfusion; Cesarean Section; Dexamethasone; Female; Fibrin; Fibrinogen; Heart Arrest; Heart Massage; Humans; Hysterectomy; Obstetric Labor Complications; Placenta Previa; Pneumonia; Postoperative Complications; Pregnancy; Pregnancy Complications, Hematologic; Thrombin

Topics: Bronchi; Bronchial Neoplasms; Carcinoma, Bronchogenic; Fibrin; Humans; Lung Diseases; Neoplasms; Pneumonia