transforming-growth-factor-beta and Respiratory-Distress-Syndrome

Macrophages are highly plastic cells. Under different stimuli, macrophages can be polarized into several different subsets. Two main macrophage subsets have been suggested: classically activated or inflammatory (M1) macrophages and alternatively activated or anti-inflammatory (M2) macrophages. Macrophage polarization is governed by a highly complex set of regulatory networks. Many recent studies have shown that macrophages are key orchestrators in the pathogenesis of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) and that regulation of macrophage polarization may improve the prognosis of ALI/ARDS. A further understanding of the mechanisms of macrophage polarization is expected to be helpful in the development of novel therapeutic targets to treat ALI/ARDS. Therefore, we performed a literature review to summarize the regulatory mechanisms of macrophage polarization and its role in the pathogenesis of ALI/ARDS.. A computer-based online search was performed using the PubMed database and Web of Science database for published articles concerning macrophages, macrophage polarization, and ALI/ARDS.. In this review, we discuss the origin, polarization, and polarization regulation of macrophages as well as the role of macrophage polarization in various stages of ARDS. According to the current literature, regulating the polarized state of macrophages might be a potential therapeutic strategy against ALI/ARDS.

Topics: Acute Lung Injury; Cell Polarity; Humans; JNK Mitogen-Activated Protein Kinases; Macrophages; NF-kappa B; Respiratory Distress Syndrome; Signal Transduction; Transforming Growth Factor beta

To review recent advances in the use of transforming growth factor (TGF)-beta in acute lung injury and to apply this knowledge to understanding the pathophysiology of this syndrome.. Published research and review articles in the English language related to the role of TGF-beta in acute lung injury.. The cytokine TGF-beta plays a critical role in the resolution of tissue injury in multiple organs, including the lung. Following injury, TGF-beta has been most thoroughly evaluated during the late phases of tissue repair, where it plays a critical role in the development of pulmonary fibrosis. In contrast, recent animal studies showed that expression levels of several TGF-beta-inducible genes were dramatically increased as early as 2 days after the induction of injury. The integrin alpha(v)beta(6) activates latent TGF-beta in the lungs. Mice lacking this integrin were completely protected from pulmonary edema in a model of bleomycin-induced acute lung injury. Pharmacologic inhibition of TGF-beta also protected wild-type mice from pulmonary edema induced by bleomycin or Escherichia coli endotoxin. Similar findings also have been reported in patients in a clinical study evaluating TGF-beta in the bronchoalveolar lavage fluid during the course of acute respiratory distress syndrome (ARDS). Indeed, the bronchoalveolar lavage concentrations were dramatically increased as early as 1 day after the initiation of ARDS criteria and were correlated with decreases in the Pao(2)/Fio(2) ratio, suggesting an important role for TGF-b1 in the development of ARDS in humans.. These studies suggest that TGF-beta not only participates in the late phase of acute lung injury, but also might be active early in acute lung injury and potentially could contribute to the development of pulmonary edema. Integrin-mediated local activation of TGF-beta is critical to the development of pulmonary edema in ARDS, and blocking TGF-beta or its activation could be an effective treatment for this disorder.

Topics: Animals; Humans; Mice; Pulmonary Fibrosis; Respiratory Distress Syndrome; Signal Transduction; Transforming Growth Factor beta

Fibrosis is a pathological process characterized by the replacement of normal tissue by mesenchymal cells and the extracellular matrix produced by these cells. The sequence of events leading to fibrosis of an organ involves the subsequent processes of injury with inflammation and disruption of the normal tissue architecture, followed by tissue repair with accumulation of mesenchymal cells in the area of derangement. The same sequence of events occurs in wound healing with normal granulation tissue and scar formation, but, while normal scar formation is very localized and transient, in contrast, in fibrosis, the repair process is exaggerated and usually widespread and can be chronic. Inflammatory cells (mainly mononuclear phagocytes), platelets, endothelial cells, and type II pneumocytes play a direct and indirect role in tissue injury and repair. The evaluation of three human fibrotic lung diseases, two diffuse [idiopathic pulmonary fibrosis (IPF), and the adult respiratory distress syndrome (ARDS)], and one focal (tumor stroma in lung cancer), has shown that several cytokines participate to the local injury and inflammatory reaction [interleukin-1 (IL-1), interleukin-8 (IL-8), monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-alpha)], while other cytokines are involved in tissue repair and fibrosis [platelet-derived growth factor (PDGF), insulin-like growth factor-1 (IGF-1), transforming growth factor-beta (TGF-beta), and basic-fibroblast growth factor (b-FGF)]. A better understanding of the cytokines and cytokine networks involved in lung fibrosis leads to the possibility of new therapeutic approaches.

Topics: Cytokines; Humans; Interleukin-1; Interleukin-8; Molecular Weight; Platelet-Derived Growth Factor; Pulmonary Fibrosis; Respiratory Distress Syndrome; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Wound Healing

Bronchiolitis obliterans syndrome (BOS) develops in one-third of lung transplant recipients. A fibroproliferative process involving mesenchymal cells is observed histopathologically. In order further to evaluate the pathomechanisms of BOS, the gene expression of platelet-derived growth factor (PDGF)-B and transforming growth factor (TGF)-beta 1 in bronchoalveolar lavage (BAL) cells of six lung transplant recipients and appropriate controls was studied. Equal amounts of total RNA were submitted to semiquantitative reverse transcription/polymerase chain reaction (RT-PCR), amplifying actin, PDGF-B and TGF-beta 1 using established protocols and primer sets. The signal/actin ratio was calculated based on laser densitometry measurements. TGF-beta 1 transcripts were detected in all samples, and a slight increase in BOS patients was observed. PDGF-B mRNA was increased in BAL samples from BOS patients compared to unaffected recipients and controls. Plotting the FEV1 in percent of vital capacity and the PDGF expression in BOS patients revealed an increased PDGF signal preceding lung function deterioration. The data were consistent with the hypothesis based mainly on in vitro findings that PDGF and TGF-beta contribute to the development of BOS.

Topics: Adult; Bronchiolitis Obliterans; Bronchoalveolar Lavage Fluid; Bronchoscopy; Cytomegalovirus Infections; Female; Gene Expression Regulation; Graft vs Host Reaction; Humans; Leukocyte Count; Lung Transplantation; Male; Middle Aged; Platelet-Derived Growth Factor; Polymerase Chain Reaction; Pulmonary Fibrosis; Respiratory Distress Syndrome; Respiratory Function Tests; RNA, Messenger; Transcription, Genetic; Transforming Growth Factor beta

Lung fibrosis is a major concern in severe COVID-19 patients undergoing mechanical ventilation (MV). Lung fibrosis frequency in post-COVID syndrome is highly variable and even if the risk is proportionally small, many patients could be affected. However, there is still no data on lung extracellular matrix (ECM) composition in severe COVID-19 and whether it is different from other aetiologies of ARDS.. We have quantified different ECM elements and TGF-β expression in lung tissue of 28 fatal COVID-19 cases and compared to 27 patients that died of other causes of ARDS, divided according to MV duration (up to six days or seven days or more). In COVID-19 cases, ECM elements were correlated with lung transcriptomics and cytokines profile.. We observed that COVID-19 cases presented significant increased deposition of collagen, fibronectin, versican, and TGF-β, and decreased decorin density when compared to non-COVID-19 cases of similar MV duration. TGF-β was precociously increased in COVID-19 patients with MV duration up to six days. Lung collagen was higher in women with COVID-19, with a transition of upregulated genes related to fibrillogenesis to collagen production and ECM disassembly along the MV course.. Fatal COVID-19 is associated with an early TGF-β expression lung environment after the MV onset, followed by a disordered ECM assembly. This uncontrolled process resulted in a prominent collagen deposition when compared to other causes of ARDS. Our data provides pathological substrates to better understand the high prevalence of pulmonary abnormalities in patients surviving COVID-19.

Topics: Collagen; COVID-19; Extracellular Matrix; Female; Humans; Lung; Pulmonary Fibrosis; Respiratory Distress Syndrome; Transforming Growth Factor beta

Progressive respiratory failure is the primary cause of death in the coronavirus disease 2019 (COVID-19) pandemic. It is the final outcome of the acute respiratory distress syndrome (ARDS), characterized by an initial exacerbated inflammatory response, metabolic derangement and ultimate tissue scarring. A positive balance of cellular energy may result crucial for the recovery of clinical COVID-19. Hence, we asked if two key pathways involved in cellular energy generation, AMP-activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) signaling and fatty acid oxidation (FAO) could be beneficial. We tested the drugs metformin (AMPK activator) and baicalin (CPT1A activator) in different experimental models mimicking COVID-19 associated inflammation in lung and kidney. We also studied two different cohorts of COVID-19 patients that had been previously treated with metformin. These drugs ameliorated lung damage in an ARDS animal model, while activation of AMPK/ACC signaling increased mitochondrial function and decreased TGF-β-induced fibrosis, apoptosis and inflammation markers in lung epithelial cells. Similar results were observed with two indole derivatives, IND6 and IND8 with AMPK activating capacity. Consistently, a reduced time of hospitalization and need of intensive care was observed in COVID-19 patients previously exposed to metformin. Baicalin also mitigated the activation of pro-inflammatory bone marrow-derived macrophages (BMDMs) and reduced kidney fibrosis in two animal models of kidney injury, another key target of COVID-19. In human epithelial lung and kidney cells, both drugs improved mitochondrial function and prevented TGF-β-induced renal epithelial cell dedifferentiation. Our results support that favoring cellular energy production through enhanced FAO may prove useful in the prevention of COVID-19-induced lung and renal damage.

Topics: AMP-Activated Protein Kinases; Animals; COVID-19; Fatty Acids; Fibrosis; Humans; Inflammation; Kidney; Lung; Metformin; Respiratory Distress Syndrome; Transforming Growth Factor beta

The acute respiratory distress syndrome (ARDS) is a major healthcare problem, accounting for significant mortality and long-term disability. Approximately 25% of patients with ARDS will develop an overexuberant fibrotic response, termed fibroproliferative ARDS (FP-ARDS) that portends a poor prognosis and increased mortality. The cellular pathological processes that drive FP-ARDS remain incompletely understood. We have previously shown that the transmembrane receptor-type tyrosine phosphatase protein tyrosine phosphatase-α (PTPα) promotes pulmonary fibrosis in preclinical murine models through regulation of transforming growth factor-β (TGF-β) signaling. In this study, we examine the role of PTPα in the pathogenesis of FP-ARDS in a preclinical murine model of acid (HCl)-induced acute lung injury. We demonstrate that although mice genetically deficient in PTPα (

Topics: Acute Lung Injury; Animals; Lung; Mice; Phosphoric Monoester Hydrolases; Pulmonary Fibrosis; Receptor-Like Protein Tyrosine Phosphatases, Class 4; Respiratory Distress Syndrome; Transforming Growth Factor beta

Topics: Alveolar Epithelial Cells; Animals; Apoptosis; Cell Proliferation; Cells, Cultured; Epithelial-Mesenchymal Transition; Female; Humans; Lipopolysaccharides; Lung Injury; Male; Mice, Inbred C57BL; Middle Aged; Phosphatidylinositol 3-Kinases; Receptors, Calcitriol; Respiratory Distress Syndrome; Signal Transduction; Transforming Growth Factor beta; Vitamin D

Topics: Alveolar Epithelial Cells; Apoptosis; Biomarkers; Bronchoalveolar Lavage Fluid; Cell Differentiation; Cell Proliferation; Cell Survival; Cell Transdifferentiation; Cells, Cultured; Collagen; Docosahexaenoic Acids; Epithelial-Mesenchymal Transition; Gene Expression Regulation; Humans; Myofibroblasts; Osmolar Concentration; Receptors, G-Protein-Coupled; Recombinant Proteins; Respiratory Distress Syndrome; Signal Transduction; Transforming Growth Factor beta; Wound Healing

Pulmonary fibrosis triggered during the early stage of acute respiratory distress syndrome (ARDS) contributes to poor prognosis in patients. However, whether microRNAs (miRNAs) can serve as therapeutic targets for early pulmonary fibrosis during ARDS is still largely unknown. In this study, we evaluated the effects and mechanisms of miR-200s and its targets ZEB1/2 in lung tissue. An early pulmonary fibrosis mouse model caused by ARDS was established via a lipopolysaccharide (LPS) three-hit regimen. Lentiviral packaged miR-200b/c cDNA or ZEB1/2 shRNA was intratracheally administered into the lungs of C57BL/6 mice 1 day before an LPS injection was administered. In vitro, following a 30-min pretreatment with miR-200b/c or SB203580/SIS3, RLE-6TN cells were stimulated by LPS or LPS + transforming growth factor-β (TGF-β) for 24 h. miR-200b/c and E-cadherin protein expression declined, whereas ZEB1/2 mRNA and protein and vimentin and α-smooth muscle actin (α-SMA) protein levels gradually increased during the development of pulmonary fibrosis. Furthermore, both the overexpression of miR-200b/c and the silencing of ZEB1/2 significantly alleviated pulmonary inflammation and fibrosis, reduced vimentin and α-SMA expression, and increased E-cadherin protein levels. In RLE-6TN cells, LPS combined with TGF-β exerts synergistic effects of increasing vimentin and α-SMA protein levels, increasing p38 and smad3 phosphorylation and reducing E-cadherin protein levels, which were reversed by pretreatment with miR-200b/c or SB203580/SIS3. Our findings demonstrate that miR-200b/c was downregulated, whereas ZEB1/2 was upregulated in the development of LPS-induced early pulmonary fibrosis. miR-200b/c exerts a protective effect by targeting ZEB1/2, which may be associated with the inhibition of p38 MAPK and TGF-β /smad3 signaling pathways.

Topics: Actins; Animals; Bronchoalveolar Lavage Fluid; Cadherins; Cell Line; Disease Models, Animal; Epithelial-Mesenchymal Transition; Lipopolysaccharides; Lung; MAP Kinase Signaling System; Mice, Inbred C57BL; MicroRNAs; Pulmonary Fibrosis; Random Allocation; Rats; Respiratory Distress Syndrome; RNA, Small Interfering; Smad3 Protein; Transforming Growth Factor beta; Vimentin; Zinc Finger E-box Binding Homeobox 2; Zinc Finger E-box-Binding Homeobox 1

Acute respiratory distress syndrome constitutes a significant disease burden with regard to both morbidity and mortality. Current therapies are mostly supportive and do not address the underlying pathophysiologic mechanisms. Removal of protein-rich alveolar edema-a clinical hallmark of acute respiratory distress syndrome-is critical for survival. Here, we describe a transforming growth factor (TGF)-β-triggered mechanism, in which megalin, the primary mediator of alveolar protein transport, is negatively regulated by glycogen synthase kinase (GSK) 3β, with protein phosphatase 1 and nuclear inhibitor of protein phosphatase 1 being involved in the signaling cascade. Inhibition of GSK3β rescued transepithelial protein clearance in primary alveolar epithelial cells after TGF-β treatment. Moreover, in a bleomycin-based model of acute lung injury, megalin

Topics: Acute Lung Injury; Animals; Glycogen Synthase Kinase 3 beta; Low Density Lipoprotein Receptor-Related Protein-2; Lung; Mice, Inbred C57BL; Mice, Knockout; Pulmonary Alveoli; Pulmonary Edema; Respiratory Distress Syndrome; Transforming Growth Factor beta

The independent impact of respiratory rate on ventilator-induced lung injury has not been fully elucidated. The aim of this study was to investigate the effects of two clinically relevant respiratory rates on early ventilator-induced lung injury evolution and lung edema during the protective ARDSNet strategy. We hypothesized that the use of a higher respiratory rate during a protective ARDSNet ventilation strategy increases lung inflammation and, in addition, lung edema associated to strain-induced activation of transforming growth factor beta (TGF-β) in the lung epithelium.. Twelve healthy piglets were submitted to a two-hit lung injury model and randomized into two groups: LRR (20 breaths/min) and HRR (40 breaths/min). They were mechanically ventilated during 6 h according to the ARDSNet strategy. We assessed respiratory mechanics, hemodynamics, and extravascular lung water (EVLW). At the end of the experiment, the lungs were excised and wet/dry ratio, TGF-β pathway markers, regional histology, and cytokines were evaluated.. No differences in oxygenation, PaCO2 levels, systemic and pulmonary arterial pressures were observed during the study. Respiratory system compliance and mean airway pressure were lower in LRR group. A decrease in EVLW over time occurred only in the LRR group (P < 0.05). Wet/dry ratio was higher in the HRR group (P < 0.05), as well as TGF-β pathway activation. Histological findings suggestive of inflammation and inflammatory tissue cytokines were higher in LRR.. HRR was associated with more pulmonary edema and higher activation of the TGF-β pathway. In contrast with our hypothesis, HRR was associated with less lung inflammation.

Topics: Animals; Arterial Pressure; Bronchoalveolar Lavage Fluid; Cytokines; Extravascular Lung Water; Hemodynamics; Humans; Organ Size; Pulmonary Edema; Respiration, Artificial; Respiratory Distress Syndrome; Respiratory Mucosa; Respiratory Rate; Sus scrofa; Swine; Transforming Growth Factor beta

Evidence suggests that tyrosine-kinase inhibitors may attenuate lung inflammation and fibrosis in experimental acute respiratory distress syndrome (ARDS). We hypothesized that dasatinib, a tyrosine-kinase inhibitor, might act differently depending on the ARDS etiology and the dose.. C57/BL6 mice were divided to be pre-treated with dasatinib (1mg/kg or 10mg/kg) or vehicle (1% dimethyl-sulfoxide) by oral gavage. Thirty-minutes after pre-treatment, mice were subdivided into control (C) or ARDS groups. ARDS animals received Escherichia coli lipopolysaccharide intratracheally (ARDSp) or intraperitoneally (ARDSexp). A new dose of dasatinib or vehicle was administered at 6 and 24h.. Forty-eight hours after ARDS induction, dasatinib 1mg/kg yielded: improved lung morphofunction and reduced cells expressing toll-like receptor (TLR)-4 in lung, independent of ARDS etiology; reduced neutrophil and levels of interleukin (IL)-6, IL-10 and transforming growth factor (TGF)-β in ARDSp. The higher dose of dasatinib caused no changes in lung mechanics, diffuse alveolar damage, neutrophil, or cells expressing TLR4, but increased IL-6, vascular endothelial growth factor (VEGF), and cells expressing Fas receptor in lung in ARDSp. In ARDSexp, it improved lung morphofunction, increased VEGF, and reduced cells expressing TLR4. Conclusion: Dasatinib may have therapeutic potential in ARDS independent of etiology, but careful dose monitoring is required.

Topics: Animals; Dasatinib; Interleukin-10; Interleukin-6; Lung; Mice, Inbred C57BL; Protein Kinase Inhibitors; Respiratory Distress Syndrome; Toll-Like Receptor 4; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A

Sepsis-induced inflammation of the lung leads to acute respiratory distress syndrome (ARDS), which may trigger persistent fibrosis. The pathology of ARDS is complex and poorly understood, and the therapeutic approaches are limited. We used a baboon model of Escherichia coli sepsis that mimics the complexity of human disease to study the pathophysiology of ARDS. We performed extensive biochemical, histological, and functional analyses to characterize the disease progression and the long-term effects of sepsis on the lung structure and function. Similar to humans, sepsis-induced ARDS in baboons displays an early inflammatory exudative phase, with extensive necrosis. This is followed by a regenerative phase dominated by proliferation of type 2 epithelial cells, expression of epithelial-to-mesenchymal transition markers, myofibroblast migration and proliferation, and collagen synthesis. Baboons that survived sepsis showed persistent inflammation and collagen deposition 6-27 months after the acute episodes. Long-term survivors had almost double the amount of collagen in the lung as compared with age-matched control animals. Immunostaining for procollagens showed persistent active collagen synthesis within the fibroblastic foci and interalveolar septa. Fibroblasts expressed markers of transforming growth factor-β and platelet-derived growth factor signaling, suggesting their potential role as mediators of myofibroblast migration and proliferation, and collagen deposition. In parallel, up-regulation of the inhibitors of extracellular proteases supports a deregulated matrix remodeling that may contribute to fibrosis. The primate model of sepsis-induced ARDS mimics the disease progression in humans, including chronic inflammation and long-lasting fibrosis. This model helps our understanding of the pathophysiology of fibrosis and the testing of new therapies.

Topics: Acute Lung Injury; Animals; Collagen; Disease Models, Animal; Escherichia coli; Fibrosis; Humans; Inflammation; Lung; Papio; Respiratory Distress Syndrome; Sepsis; Signal Transduction; Transforming Growth Factor beta

TGF-β is a pathogenic factor in patients with acute respiratory distress syndrome (ARDS), a condition characterized by alveolar edema. A unique TGF-β pathway is described, which rapidly promoted internalization of the αβγ epithelial sodium channel (ENaC) complex from the alveolar epithelial cell surface, leading to persistence of pulmonary edema. TGF-β applied to the alveolar airspaces of live rabbits or isolated rabbit lungs blocked sodium transport and caused fluid retention, which--together with patch-clamp and flow cytometry studies--identified ENaC as the target of TGF-β. TGF-β rapidly and sequentially activated phospholipase D1, phosphatidylinositol-4-phosphate 5-kinase 1α, and NADPH oxidase 4 (NOX4) to produce reactive oxygen species, driving internalization of βENaC, the subunit responsible for cell-surface stability of the αβγENaC complex. ENaC internalization was dependent on oxidation of βENaC Cys(43). Treatment of alveolar epithelial cells with bronchoalveolar lavage fluids from ARDS patients drove βENaC internalization, which was inhibited by a TGF-β neutralizing antibody and a Tgfbr1 inhibitor. Pharmacological inhibition of TGF-β signaling in vivo in mice, and genetic ablation of the nox4 gene in mice, protected against perturbed lung fluid balance in a bleomycin model of lung injury, highlighting a role for both proximal and distal components of this unique ENaC regulatory pathway in lung fluid balance. These data describe a unique TGF-β-dependent mechanism that regulates ion and fluid transport in the lung, which is not only relevant to the pathological mechanisms of ARDS, but might also represent a physiological means of acutely regulating ENaC activity in the lung and other organs.

Topics: Acute Lung Injury; Adenosine Triphosphatases; Adult; Aged; Animals; Epithelial Sodium Channels; Female; Gene Expression Regulation; Humans; Ions; Lung; Male; Mice; Mice, Knockout; Middle Aged; Perfusion; Phospholipase D; Phosphotransferases (Alcohol Group Acceptor); Pulmonary Alveoli; Rabbits; Reactive Oxygen Species; Respiratory Distress Syndrome; Transforming Growth Factor beta

Diabetic patients have a lower incidence of acute respiratory distress syndrome (ARDS), and those who develop ARDS are less likely to die. The mechanisms that underlie this protection are unknown.. To determine whether leptin resistance, a feature of diabetes, prevents fibroproliferation after lung injury.. We examined lung injury and fibroproliferation after the intratracheal instillation of bleomycin in wild-type and leptin-resistant (db/db) diabetic mice. We examined the effect of leptin on transforming growth factor (TGF)-β(1)-mediated transcription in primary normal human lung fibroblasts. Bronchoalveolar lavage fluid (BAL) samples from patients with ARDS and ventilated control subjects were obtained for measurement of leptin and active TGF-β(1) levels.. Diabetic mice (db/db) were resistant to lung fibrosis. The db/db mice had higher levels of peroxisome proliferator-activated receptor-γ (PPARγ), an inhibitor of the transcriptional response to TGF-β(1), a cytokine critical in the pathogenesis of fibroproliferative ARDS. In normal human lung fibroblasts, leptin augmented the transcription of profibrotic genes in response to TGF-β(1) through a mechanism that required PPARγ. In patients with ARDS, BAL leptin levels were elevated and correlated with TGF-β(1) levels. Overall, there was no significant relationship between BAL leptin levels and clinical outcomes; however, in nonobese patients, higher BAL leptin levels were associated with fewer intensive care unit- and ventilator-free days and higher mortality.. Leptin signaling is required for bleomycin-induced lung fibrosis. Leptin augments TGF-β(1) signaling in lung fibroblasts by inhibiting PPARγ. These findings provide a mechanism for the observed protection against ARDS observed in diabetic patients.

Topics: Animals; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Female; Humans; Leptin; Lung; Male; Mice; Middle Aged; PPAR gamma; Respiratory Distress Syndrome; Transforming Growth Factor beta

Pneumonectomy is associated with high rates of morbimortality, with postpneumonectomy pulmonary edema being one of the leading causes. An intrinsic inflammatory process following the operation has been considered in its physiopathology. The use of corticosteroids is related to prevention of this edema, but no experimental data are available to support this hypothesis. We evaluated the effect of methylprednisolone on the remaining lungs of rats submitted to left pneumonectomy concerning edema and inflammatory markers. Forty male Wistar rats weighing 300 g underwent left pneumonectomy and were randomized to receive corticosteroids or not. Methylprednisolone at a dose of 10 mg/kg was given before the surgery. After recovery, the animals were sacrificed at 48 and 72 h, when the pO(2)/FiO(2) ratio was determined. Right lung perivascular edema was measured by the index between perivascular and vascular area and neutrophil density by manual count. Tissue expression of vascular endothelial growth factor (VEGF) and transforming growth factor-beta (TGF-β) were evaluated by immunohistochemistry light microscopy. There was perivascular edema formation after 72 h in both groups (P = 0.0031). No difference was observed between operated animals that received corticosteroids and those that did not concerning the pO(2)/FiO(2) ratio, neutrophil density or TGF-β expression. The tissue expression of VEGF was elevated in the animals that received methylprednisolone both 48 and 72 h after surgery (P = 0.0243). Methylprednisolone was unable to enhance gas exchange and avoid an inflammatory infiltrate and TGF-β expression also showed that the inflammatory process was not correlated with pulmonary edema formation. However, the overexpression of VEGF in this group showed that methylprednisolone is related to this elevation.

Topics: Analysis of Variance; Animals; Anti-Inflammatory Agents; Disease Models, Animal; Drug Evaluation, Preclinical; Glucocorticoids; Immunohistochemistry; Lung; Male; Methylprednisolone; Pneumonectomy; Pulmonary Edema; Random Allocation; Rats; Rats, Wistar; Respiratory Distress Syndrome; Transforming Growth Factor beta; Vascular Endothelial Growth Factors

Acute respiratory distress syndrome is characterized by loss of lung tissue as a result of inflammation and fibrosis. Augmenting tissue repair by the use of mesenchymal stem cells may be an important advance in treating this condition. We evaluated the role of term human umbilical cord cells derived from Wharton's jelly with a phenotype consistent with mesenchymal stem cells (uMSCs) in the treatment of a bleomycin-induced mouse model of lung injury. uMSCs were administered systemically, and lungs were harvested at 7, 14, and 28 days post-bleomycin. Injected uMSCs were located in the lung 2 weeks later only in areas of inflammation and fibrosis but not in healthy lung tissue. The administration of uMSCs reduced inflammation and inhibited the expression of transforming growth factor-beta, interferon-gamma, and the proinflammatory cytokines macrophage migratory inhibitory factor and tumor necrosis factor-alpha. Collagen concentration in the lung was significantly reduced by uMSC treatment, which may have been a consequence of the simultaneous reduction in Smad2 phosphorylation (transforming growth factor-beta activity). uMSCs also increased matrix metalloproteinase-2 levels and reduced their endogenous inhibitors, tissue inhibitors of matrix metalloproteinases, favoring a pro-degradative milieu following collagen deposition. Notably, injected human lung fibroblasts did not influence either collagen or matrix metalloproteinase levels in the lung. The results of this study suggest that uMSCs have antifibrotic properties and may augment lung repair if used to treat acute respiratory distress syndrome.

Topics: Animals; Antibiotics, Antineoplastic; Bleomycin; Blotting, Western; Collagen; Cord Blood Stem Cell Transplantation; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Fetal Blood; Humans; Immunohistochemistry; Inflammation; Lung Injury; Macrophage Migration-Inhibitory Factors; Matrix Metalloproteinase 2; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Mice, SCID; Polymerase Chain Reaction; Pulmonary Fibrosis; Respiratory Distress Syndrome; RNA, Messenger; Tissue Inhibitor of Metalloproteinases; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Deletion of integrin alphav beta6 has been associated with significant protection in experiments where lung injury was induced by bleomycin, lipophilic polysaccharides, and high tidal volume ventilation. This has led to the suggestion that antibody blockade of this integrin is a novel therapy for acute lung injury. We questioned whether beta6 gene deletion would also protect against Pseudomonas aeruginosa-induced acute lung injury. Wild-type and littermate beta6-null mice, as well as recombinant soluble TGF-beta receptor type II-Fc (rsTGF-betaRII-Fc) and anti-alphav beta6 treated wild-type mice, were instilled with live P. aeruginosa. Four or 8 h after bacterial instillation, the mice were euthanized, and either bronchoalveolar lavage fluid or lung homogenates were obtained. Deletion of the beta6 gene resulted in an overall increase in inflammatory cells in the lungs. Bacterial numbers from the lung homogenates of infected beta6-null mice were significantly decreased compared to the numbers in the wild-type mice (1.6 x 10(6) CFU versus 4.2 x 10(6) CFU [P < 0.01]). There were no significant differences in P. aeruginosa-mediated increases in lung endothelial permeability between wild-type and beta6-null mice. Similarly, pretreatment with the alphav beta6 antibody or with rsTGF-betaRII-Fc did not significantly affect the P. aeruginosa-induced lung injury or rate of survival compared to pretreatment with control immunoglobulin G. We conclude that deletion or inhibition of the integrin alphav beta6 did not protect animals from P. aeruginosa-induced lung injury. However, these therapies also did not increase the lung injury, suggesting that host defense was not compromised by this promising new therapy.

Topics: Animals; Antibodies, Blocking; Antigens, Neoplasm; Bronchoalveolar Lavage Fluid; Cytokines; Gene Deletion; Gene Expression Regulation; Integrins; Macrophages, Alveolar; Mice; Mice, Knockout; Phagocytosis; Pseudomonas aeruginosa; Pseudomonas Infections; Receptors, Transforming Growth Factor beta; Respiratory Distress Syndrome; Transforming Growth Factor beta

There has been ongoing controversy related to what differentiates normal lung repair and fibrosis. For example, the current prevailing concept has been that idiopathic forms of pulmonary fibrosis are due only to epithelial injury in response to some unknown cause that results in persistent evolving fibrosis without preceding inflammation. This concept would suggest that the lung responds to injury in a different manner than other organs, such as the liver, kidney, and heart. However, that would seem to contradict known established pathological concepts. To address this controversy, concepts were presented as follows: (1) loss of basement membrane integrity is critical in determining the "point of no return," and contributes to the inability to reestablish normal lung architecture with promotion of fibrosis; (2) loss of epithelial cells, endothelial cells, and basement membrane integrity in usual interstitial pneumonia associated with idiopathic pulmonary fibrosis leads to destroyed lung architecture and perpetual fibrosis; (3) transforming growth factor-beta is necessary, but not entirely sufficient, to promote permanent fibrosis; (4) persistent injury/antigen/irritant is critical for the propagation of fibrosis; (5) idiopathic pulmonary fibrosis is an example of a process related to the persistence of an "antigen(s)," chronic inflammation, and fibrosis; and (6) unique cells are critical cellular players in the regulation of fibrosis. In keeping with the theme of the Aspen Lung Conference, it is hoped that more questions are raised than answered in this presentation, in support of the continued need for research in this area to address these important concepts.

Topics: Basement Membrane; Endothelial Cells; Humans; Inflammation; Lung; Lung Diseases, Interstitial; Macrophages, Alveolar; Pulmonary Fibrosis; Respiratory Distress Syndrome; Respiratory Mucosa; Transforming Growth Factor beta; Wound Healing

To determine whether an anti-transforming growth factor-beta (TGF-beta) type 1 receptor inhibitor (SM16) can prevent radiation-induced lung injury.. One fraction of 28 Gy or sham radiotherapy (RT) was administered to the right hemithorax of Sprague-Dawley rats. SM16 was administered in the rat chow (0.07 g/kg or 0.15 g/kg) beginning 7 days before RT. The rats were divided into eight groups: group 1, control chow; group 2, SM16, 0.07 g/kg; group 3, SM16, 0.15 g/kg; group 4, RT plus control chow; group 5, RT plus SM16, 0.07 g/kg; group 6, RT plus SM16, 0.15 g/kg; group 7, RT plus 3 weeks of SM16 0.07 g/kg followed by control chow; and group 8, RT plus 3 weeks of SM16 0.15 g/kg followed by control chow. The breathing frequencies, presence of inflammation/fibrosis, activation of macrophages, and expression/activation of TGF-beta were assessed.. The breathing frequencies in the RT plus SM16 0.15 g/kg were significantly lower than the RT plus control chow from Weeks 10-22 (p <0.05). The breathing frequencies in the RT plus SM16 0.07 g/kg group were significantly lower only at Weeks 10, 14, and 20. At 26 weeks after RT, the RT plus SM16 0.15 g/kg group experienced a significant decrease in lung fibrosis (p = 0.016), inflammatory response (p = 0.006), and TGF-beta1 activity (p = 0.011). No significant reduction was found in these measures of lung injury in the group that received SM16 0.7 g/kg nor for the short-course (3 weeks) SM16 at either dose level.. SM16 at a dose of 0.15 g/kg reduced functional lung damage, morphologic changes, inflammatory response, and activation of TGF-beta at 26 weeks after RT. The data suggest a dose response and also suggest the superiority of long-term vs. short-term dosing.

Topics: Animals; Azabicyclo Compounds; Dose-Response Relationship, Drug; Female; Radiation Injuries; Radiation-Protective Agents; Radiotherapy; Rats; Rats, Sprague-Dawley; Respiratory Distress Syndrome; Transforming Growth Factor beta; Treatment Outcome

The acute respiratory distress syndrome (ARDS) is characterized by non-cardiogenic pulmonary edema and flooding of the alveolar air spaces with proteinaceous fluid. ARDS develops in response to inflammatory stresses including sepsis, trauma, and severe pneumonia, and despite aggressive critical care management, it still has a mortality of 30-50%. At the time of its original description in 1967, relatively little was known about the specific mechanisms by which the alveolar epithelium regulated lung fluid balance. Over the last 20 years, substantial advances in our understanding of the alveolar epithelium have provided major new insights into how molecular and cellular mechanisms regulate the active transport of solutes and fluid across the alveolar epithelium under both normal and pathological conditions. Beginning with the elucidation of active sodium transport as a major driving force for the transport of water from the air space to the interstitium, elegant work by multiple investigators has revealed a complex and integrated network of membrane channels and pumps that coordinately regulates sodium, chloride, and water flux in both a cell- and condition-specific manner. At the Experimental Biology Meeting in San Francisco on April 4, 2006, a symposium was held to discuss some of the most recent advances. Although there is still much to learn about the mechanisms that impair normal alveolar fluid clearance under pathological conditions, the compelling experimental findings presented in this symposium raise the prospect that we are now poised to test and develop therapeutic strategies to improve outcome in patients with acute lung injury.

Topics: Adrenergic Agents; Biological Transport, Active; Cell Hypoxia; Epithelial Sodium Channels; Epithelium; Extravascular Lung Water; Humans; Ion Channels; Models, Biological; Pulmonary Alveoli; Respiratory Distress Syndrome; RNA, Small Interfering; Sodium Channels; Transforming Growth Factor beta

Activation of latent TGF-beta by the alpha(v)beta6 integrin is a critical step in the development of acute lung injury. However, the mechanism by which alpha(v)beta6-mediated TGF-beta activation is regulated has not been identified. We show that thrombin, and other agonists of protease-activated receptor 1 (PAR1), activate TGF-beta in an alpha(v)beta6 integrin-specific manner. This effect is PAR1 specific and is mediated by RhoA and Rho kinase. Intratracheal instillation of the PAR1-specific peptide TFLLRN increases lung edema during high-tidal-volume ventilation, and this effect is completely inhibited by a blocking antibody against the alpha(v)beta6 integrin. Instillation of TFLLRN during high-tidal-volume ventilation is associated with increased pulmonary TGF-beta activation; however, this is not observed in Itgb6-/- mice. Furthermore, Itgb6-/- mice are also protected from ventilator-induced lung edema. We also demonstrate that pulmonary edema and TGF-beta activity are similarly reduced in Par1-/- mice following bleomycin-induced lung injury. These results suggest that PAR1-mediated enhancement of alpha(v)beta6-dependent TGF-beta activation could be one mechanism by which activation of the coagulation cascade contributes to the development of acute lung injury, and they identify PAR1 and the alpha(v)beta6 integrin as potential therapeutic targets in this condition.

Topics: Amides; Animals; Antibiotics, Antineoplastic; Bleomycin; Cells, Cultured; Enzyme Inhibitors; Epithelial Cells; Humans; Integrins; Intracellular Signaling Peptides and Proteins; Lung; Mice; Mice, Knockout; Peptides; Protein Serine-Threonine Kinases; Pulmonary Edema; Pyridines; Receptor, PAR-1; Respiratory Distress Syndrome; rho-Associated Kinases; rhoA GTP-Binding Protein; Thrombin; Transforming Growth Factor beta

Fibroproliferation markers like procollagen I predict mortality in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). We sought to determine whether bronchoalveolar lavage fluid (BALF) from patients with lung injury contained mediators that would activate procollagen I promoter and if this activation predicted important clinical outcomes.. Prospective controlled study of ALI/ARDS.. Intensive care units and laboratory of a university hospital.. Acute lung injury/ARDS, cardiogenic edema (negative controls) and pulmonary fibrosis (positive controls) patients.. Bronchoalveolar lavage fluid was collected within 48 h of intubation from ALI/ARDS patients. BALF was also collected from patients with pulmonary fibrosis and cardiogenic pulmonary edema. Human lung fibroblasts were transfected with a procollagen I promoter-luciferase construct and incubated with BALF; procollagen I promoter activity was then measured. BALF active TGF-beta1 levels were measured by ELISA.. Twenty-nine ARDS patients, nine negative and six positive controls were enrolled. BALF from ARDS patients induced 41% greater procollagen I promoter activation than that from negative controls (p<0.05) and a TGF-beta1 blocking antibody significantly reduced this activation in ARDS patients. There was a trend toward higher TGF-beta1 levels in the ARDS group compared to negative controls (-1.056 log(10)+/-0.1415 vs -1.505 log(10)+/-0.1425) (p<0.09). Procollagen I promoter activation was not associated with mortality; however, lower TGF-beta1 levels were associated with more ventilator-free and ICU-free days.. Bronchoalveolar lavage fluid from ALI/ARDS patients activates procollagen I promoter, which is due partly to TGF-beta1. Activated TGF-beta1 may impact ARDS outcome independent of its effect on procollagen I activation.

Topics: Bronchoalveolar Lavage Fluid; Case-Control Studies; Female; Humans; Male; Middle Aged; Procollagen; Respiratory Distress Syndrome; Severity of Illness Index; Transforming Growth Factor beta; Transforming Growth Factor beta1

Acute lung injury can occur from multiple causes, resulting in high mortality. The pathophysiology of nickel-induced acute lung injury in mice is remarkably complex, and the molecular mechanisms are uncertain.. To integrate molecular pathways and investigate the role of transforming growth factor beta (TGF-beta) in acute lung injury in mice.. cDNA microarray analyses were used to identify lung gene expression changes after nickel exposure. MAPPFinder analysis of the microarray data was used to determine significantly altered molecular pathways. TGF-beta1 protein in bronchoalveolar lavage fluid, as well as the effect of inhibition of TGF-beta, was assessed in nickel-exposed mice. The effect of TGF-beta on surfactant-associated protein B (Sftpb) promoter activity was measured in mouse lung epithelial cells.. Genes that decreased the most after nickel exposure play important roles in lung fluid absorption or surfactant and phospholipid synthesis, and genes that increased the most were involved in TGF-beta signaling. MAPPFinder analysis further established TGF-beta signaling to be significantly altered. TGF-beta-inducible genes involved in the regulation of extracellular matrix function and fibrinolysis were significantly increased after nickel exposure, and TGF-beta1 protein was also increased in the lavage fluid. Pharmacologic inhibition of TGF-beta attenuated nickel-induced protein in bronchoalveolar lavage. In addition, treatment with TGF-beta1 dose-dependently repressed Sftpb promoter activity in vitro, and a novel TGF-beta-responsive region in the Sftpb promoter was identified.. These data suggest that TGF-beta acts as a central mediator of acute lung injury through the alteration of several different molecular pathways.

Topics: Animals; Bronchoalveolar Lavage Fluid; Cells, Cultured; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Female; Fibrinolysis; Gene Expression; Mice; Nickel; Oligonucleotide Array Sequence Analysis; Pulmonary Surfactant-Associated Protein B; Respiratory Distress Syndrome; Respiratory Mucosa; Reverse Transcriptase Polymerase Chain Reaction; RNA; Signal Transduction; Transforming Growth Factor beta; Transforming Growth Factor beta1

To study the pulmonary inflammatory reaction induced by N-protein of SARS-CoV in rat models and the effects of glucocorticoids on the inflammatory reaction.. The pulmonary inflammatory reaction in rat models were induced by intratracheal instillation of N-protein of SARS-CoV with a dose of 0.2 mg/kg. The rats were randomly divided into four groups: normal saline control group (Nc group), N-protein group 1 (P1 group, 6 h), N-protein group 2 (P2 group, 24 h), and N-protein + dexamethasone group (P + D group, dexamethasone 10 mg/kg intraperitoneally). The blood samples, bronchial alveolar lavage fluid (BALF) and lung tissue were collected after challenge. The cytological and histopathologic changes of lung tissues were observed and the wet/dry ratios (W/D) of lung tissue were determined. The interleukin (IL)-6, IL-10 and transforming growth factor-beta1 (TGF-beta1) of serum and BALF were measured by ELISA.. (1) Compared with the percentage of peripheral blood lymphocytes in Nc group [(68.42 +/- 13.07)%], that in P2 group [(50.50 +/- 14.36)%] was significantly decreased (P < 0.05); compared with Nc group and P2 group, that in P + D group was furthermore significantly decreased (P < 0.01). Compared with the total WBC of peripheral blood in Nc group [(5.86 +/- 2.25) x 10(9)] and P2 group [(4.83 +/- 1.49) x 10(9)], that in P + D group [(1.96 +/- 1.30) x 10(9)] was significantly decreased (P < 0.01). (2) Compared with the total WBC of BALF in Nc group [(95 +/- 29) x 10(7)], that in P2 group [(160 +/- 60) x 10(7)] was significantly increased (P < 0.05); but compared with P2 group, that in P + D group [(62 +/- 23) x 10(7)] was significantly decreased (P < 0.05). Analysis of BALF differential cell counts showed that the majority of cells were alveolar macrophages in all groups. (3) The W/D ratios of lung tissue in both P1 and P2 group [(5.18 +/- 0.29) and (5.19 +/- 0.34), respectively] after N-protein challenge were significantly increased than that in Nc groups [(4.77 +/- 0.27), P < 0.05]; the W/D ratio in P + D group (4.70 +/- 0.18) was significantly decreased than that in P2 group (P < 0.01). (4) Compared with Nc group, the levels of IL-6, IL-10, TGF-beta1 in both serum and BALF of P1 group were significantly increased (P < 0.01), and the levels of these cytokines in P2 group were significantly higher than those in P1 group (P < 0.01), but significantly lower in P + D group compared with P2 group (P < 0.01).. The N-protein of SARS-CoV had pathogenicity and could induce obvious pulmonary inflammatory reaction and acute lung injury, which were related to the increase and imbalance of pro-inflammatory and anti-inflammatory cytokines. Glucocorticoids could effectively alleviate the pulmonary inflammatory reaction induced by N-protein of SARS-CoV.

Topics: Animals; Bronchoalveolar Lavage Fluid; Coronavirus Nucleocapsid Proteins; Dexamethasone; Glucocorticoids; Inflammation; Interleukin-10; Interleukin-6; Leukocyte Count; Lung; Male; Nucleocapsid Proteins; Random Allocation; Rats; Rats, Sprague-Dawley; Respiratory Distress Syndrome; Transforming Growth Factor beta; Transforming Growth Factor beta1

The aim of this study is to investigate whether ambroxol inhibits inflammatory responses in a murine model of lipopolysaccharide-induced acute lung injury (ALI).. Mice (n=295) were first intratracheally instilled with lipopolysaccharide (LPS) to induce ALI and then received an intraperitoneal (i.p.) injection of either normal saline (NS), ambroxol (30 or 90 mg/kg per day) or dexamethasone (2.5 or 5 mg/kg per day) for 7 days. Metabolism (n=10, each), lung morphology (n=5, each) and wet-to-dry lung weight ratio (n=10, each) were studied. The levels of tumor necrosis factor (TNF-alpha), interleukin-6 (IL-6) and transforming growth factor (TGF-beta1) and the protein concentration (n=5 or 7, each) in bronchoalveolar lavage (BAL) were measured.. Mice with LPS-induced ALI that were treated with ambroxol at a dosage of 90 mg/kg per day significantly gained weight compared to the control and dexamethasone-treated groups. Ambroxol and dexamethasone significantly reduced the lung hemorrhage, edema, exudation, neutrophil infiltration and total lung injury histology score at 24 and 48 h. In addition, ambroxol and dexamethasone significantly attenuated the lung wet-to-dry weight ratio at 24 and 48 h (p<0.05). Compared to the control group, TNF-alpha, IL-6 and TGF-beta1 levels in the BAL in both ambroxol- and dexamethasone-treated groups were significantly reduced at 24 and 48 h. The protein in BAL, an index of vascular permeability, was also significantly decreased in the ambroxol- and dexamethasone-treated groups (p<0.05).. Ambroxol inhibited proinflammatory cytokines, reduced lung inflammation and accelerated recovery from LPS-induced ALI.

Topics: Ambroxol; Animals; Anti-Inflammatory Agents; Bronchoalveolar Lavage Fluid; Dexamethasone; Disease Models, Animal; Drug Administration Schedule; Drug Evaluation, Preclinical; Expectorants; Inflammation; Instillation, Drug; Interleukin-6; Lipopolysaccharides; Mice; Organ Size; Proteins; Respiratory Distress Syndrome; Severity of Illness Index; Sodium Chloride; Transforming Growth Factor beta; Transforming Growth Factor beta1; Tumor Necrosis Factor-alpha; Weight Gain

To observe the influence of Niupo Zhibao pellet (NZP) on transforming growth factor-beta1 (TGF-beta1) and its receptor's expression.. Endotoxic shock model was established by intravenous injection of lipopolysaccharide (LPS) 1.5 mg/kg and intraperitoneal injection of D-galactosamine 100 mg/kg, and intervened by NZP, TGF-beta1 and its receptor's expression in lung tissue were detected by immunohistochemical method.. NZP could enhance the TGF-beta1 and its receptor's expression in endotoxic shock lung tissue, and reduce the injury of lung.. The mechanism of NZP in reducing endotoxic shock lung injury is possibly related with its effect in enhancing the TGF-beta1 and its receptor's expression in lung tissue.

Topics: Animals; Drugs, Chinese Herbal; Female; Galactosamine; Lipopolysaccharides; Male; Rats; Rats, Sprague-Dawley; Receptors, Transforming Growth Factor beta; Respiratory Distress Syndrome; Shock, Septic; Transforming Growth Factor beta; Transforming Growth Factor beta1

The acute respiratory distress syndrome (ARDS) remains a major cause of morbidity and mortality. Enhanced fibrosis and elevated procollagen III levels have been linked to increased mortality. We hypothesized that transforming growth factor (TGF)-beta 1 may play an important role in ARDS, given its role in stimulating fibrosis. Using reverse transcriptase in situ polymerase chain reaction (RT in situ PCR) and immunohistochemistry, we analyzed lung tissue from four fibroproliferative ARDS cases and control subjects. We also compared active TGF-beta 1 levels in the bronchoalveolar lavage (BAL) fluid of 13 de novo ARDS cases, and 7 normal control subjects. RT in situ PCR showed TGF-beta 1 mRNA expression in fibroproliferative ARDS cases. Immunohistochemistry confirmed protein expression in these samples. Controls were negative for both techniques. In the newly enrolled ARDS cases, TGF-beta 1 levels, as measured by luciferase assay, were elevated in the 11 of 13 samples, averaging 98 +/- 40 pg/mg protein. Controls had no detectable TGF-beta 1 activity. These data suggest that activation of TGF-beta 1 may be important in the early phases of acute lung injury in addition to driving fibroproliferation. These data may lead to new therapeutic approaches in ARDS through more targeted inhibition of fibrosis.

Topics: Acute Disease; Bronchoalveolar Lavage Fluid; Genes, Reporter; Humans; Immunohistochemistry; Luciferases; Respiratory Distress Syndrome; Reverse Transcriptase Polymerase Chain Reaction; Transforming Growth Factor beta; Transforming Growth Factor beta1

Interleukin-1 (IL-1) is increased in lung lavages obtained from patients with acute lung injury (ALI) and administering recombinant human IL-1alpha (rhIL-1alpha) (50 ng) intratracheally causes an acute, neutrophil-dependent, oxidative lung leak in rats that closely resembles human ALI. In the present work, the authors tested the hypothesis that transforming growth factor beta (TGFbeta) contributes to the lung inflammation and injury that develops in rats given IL-1 intratracheally. They found that intravenous administration of a monoclonal antibody to TGFbeta (1.D.11.16, 0.5 mg/kg) attenuated lung injury responses, specifically lung leak index, lung lavage protein concentrations, and blood oxygenation abnormalities, that are observed 5 hours after intratracheal instillation of IL-1 in rats, but did not decrease indices of lung inflammation, specifically myeloperoxidase (MPO) activity in lung tissue, neutrophil counts in lung lavage, and cytokine-induced neutrophil chemoattractant (CINC) levels in lung lavage, in rats given IL-1 intratracheally. The results suggest that TGFbeta contributes to lung leak, but not lung inflammation, following intratracheal administration of IL-1 in rats.

Topics: Animals; Antibodies, Monoclonal; Bronchoalveolar Lavage Fluid; Cells, Cultured; Chemokines, CXC; Intercellular Signaling Peptides and Proteins; Interleukin-1; Leukocyte Count; Lung; Neutrophils; Oxygen; Peroxidase; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Respiratory Distress Syndrome; Transforming Growth Factor beta

Expression microarrays are a powerful tool that could provide new information about the molecular pathways regulating common lung diseases. To exemplify how this tool can be useful, selected examples of informative experiments are reviewed. In studies relevant to asthma, the cytokine interleukin-13 has been shown to produce many of the phenotypic features of this disease, but the cellular targets in the airways and the molecular pathways activated are largely unknown. We have used microarrays to begin to dissect the different transcriptional responses of primary lung cells to this cytokine. In experiments designed to identify global transcriptional programs responsible for regulating lung inflammation and pulmonary fibrosis, we performed microarray experiments on lung tissue from wild-type mice and mice lacking a member of the integrin family know to be involved in activation of latent transforming growth factor (TGF)-beta. In addition to identifying distinct cluster of genes involved in each of these processes, these studies led to the identification of novel pathways by which TGF-beta can regulate acute lung injury and emphysema. Together, these examples demonstrate how careful application and thorough analysis of expression microarrays can facilitate the discovery of novel molecular targets for intervening in common lung diseases.

Topics: Animals; Antigens, Neoplasm; Asthma; Gene Expression; Genes, Regulator; Genetic Predisposition to Disease; Humans; In Vitro Techniques; Integrins; Interleukin-13; Lung; Matrix Metalloproteinase 12; Matrix Metalloproteinase 7; Metalloendopeptidases; Mice; Mice, Knockout; Oligonucleotide Array Sequence Analysis; Pulmonary Emphysema; Pulmonary Fibrosis; Respiratory Distress Syndrome; Transcriptional Activation; Transforming Growth Factor beta

Activated neutrophils contribute to the development of ventilator-induced lung injury (VILI) caused by high-pressure mechanical ventilation. However, exact cellular and molecular mechanisms have not been conclusively studied. Our investigation aimed to examine expression of adhesion molecules by both neutrophils and macrophages in lung lavage fluids of rats with VILI. Further, involvement of proinflammatory (tumor necrosis factor-alpha) and profibrogenetic (transforming growth factor-beta 1) mediators was analyzed at mRNA level in lung tissue. Wistar rats were ventilated by high pressure (45 cm H(2)O of peak inspiratory pressure, n = 23) or low pressure (7 cm H(2)O, n = 13) with 0 positive end-expiratory pressure. After 40 min of comparative ventilation, lung lavage was performed in 20 rats from the experimental group and 10 from the control for immunofluorescence analysis with anti-Mac-1 and anti-ICAM-1 monoclonal antibodies. The lung tissues from remaining rats were subjected to pathological and reverse transcription-polymerase chain reaction examinations. Although there was no significant change of PaO(2) in the low-pressure group, PaO(2) was decreased in the high-pressure group. The high-pressure group also had greater neutrophil infiltration into alveolar spaces, upregulation of CD54 and CD11b on alveolar macrophages, and more transforming growth factor-beta 1 mRNA in lung tissues. Tumor necrosis factor-alpha was not involved in the pathogenesis of the severe VILI observed. Histologic findings also demonstrated more infiltrating neutrophils, destructive change of the alveolar wall, and deposition of matrix in the high-pressure group. These results suggest that a series of proinflammatory reactions and profibrogenetic process may be involved in the course of VILI.

Topics: Animals; Intercellular Adhesion Molecule-1; Lung; Macrophage Activation; Macrophage-1 Antigen; Male; Neutrophils; Rats; Rats, Wistar; Respiration, Artificial; Respiratory Distress Syndrome; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Up-Regulation

We have shown that the integrin alphavbeta6 activates latent TGF-beta in the lungs and skin. We show here that mice lacking this integrin are completely protected from pulmonary edema in a model of bleomycin-induced acute lung injury (ALI). Pharmacologic inhibition of TGF-beta also protected wild-type mice from pulmonary edema induced by bleomycin or Escherichia coli endotoxin. TGF-beta directly increased alveolar epithelial permeability in vitro by a mechanism that involved depletion of intracellular glutathione. These data suggest that integrin-mediated local activation of TGF-beta is critical to the development of pulmonary edema in ALI and that blocking TGF-beta or its activation could be effective treatments for this currently untreatable disorder.

Topics: Animals; Antigens, Neoplasm; Bleomycin; Blood-Air Barrier; Cells, Cultured; Endotoxins; Glutathione; Integrins; Mice; Mice, Knockout; Protein Serine-Threonine Kinases; Pulmonary Alveoli; Pulmonary Edema; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Respiratory Distress Syndrome; Transforming Growth Factor beta

Acute lung injury, characterized as the adult respiratory distress syndrome (ARDS), is a common clinical occurrence following blood loss and injury. We previously found increased levels of transforming growth factor (TGF)-beta 1 mRNA in murine intraparenchymal mononuclear cells and in alveolar macrophages within 1 h after hemorrhage. Because TGF-beta has potent proinflammatory and immunoregulatory properties, we investigated the effect of blocking TGF-beta with mAb on hemorrhage-induced pathology, cytokine mRNA levels in lungs, as well as survival from pneumonia. Mice treated with anti-TGF-beta mAb showed normal pulmonary histology 3 days after hemorrhage and resuscitation in contrast to the mononuclear and neutrophil infiltrates, intraalveolar hemorrhage, and interstitial edema found in hemorrhaged mice either treated with control antibody or not treated with any antibody. Decreased mRNA levels for IL-1 beta, TNF-alpha, IL-6, IL-10, and IFN-gamma as compared with untreated, hemorrhaged controls were present in intraparenchymal pulmonary mononuclear cells following therapy with anti-TGF-beta. In contrast, therapy with anti-TGF-beta increased mRNA levels for IL-1 beta and TNF-alpha in alveolar macrophages and for TGF-beta in peripheral blood mononuclear cells collected 3 days after hemorrhage. Administration of anti-TGF-beta to hemorrhaged mice did not correct the enhanced susceptibility to Pseudomonas aeruginosa pneumonia that exists after hemorrhage. These results suggest that TGF-beta has an important role in hemorrhage-induced acute lung injury, but does not contribute to the post-hemorrhage depression in pulmonary antibacterial response.

Topics: Animals; Antibodies, Monoclonal; Cytokines; Disease Models, Animal; Gene Expression; Hemorrhage; Leukocytes, Mononuclear; Lung; Macrophages, Alveolar; Male; Mice; Mice, Inbred BALB C; Monocytes; Pneumonia; Pseudomonas Infections; Respiratory Distress Syndrome; Resuscitation; RNA, Messenger; Transforming Growth Factor beta