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Query: UMLS:C0242706 (hyperoxia)
 5,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hyper or hypoxia may affect the immune system's chemokine production. Monocyte chemotactic protein-1 (MCP-1), an important chemotactic cytokine can be activated by active oxygen species. Groups of rats were exposed to hypoxic and hyperoxic environmental conditions for 60 h and MCP-1 was determined in their peripheral blood mononuclear cells by Elisa and Reverse Transcriptase Polymerase Chain Reaction (RT-PCR). In this study we evaluated if the ability of monocytes to produce MCP-1 under basal conditions or after stimulation with lipopolysaccharide (LPS) or phytohaemagglutinin (PHA) was differently affected by exposure to hyper or hypoxic conditions in young and aged rats. MCP-1 expression and production in monocyte/macrophages from rats at normoxic conditions was reduced in aged subjects. However, spontaneous, LPS or PHA-induced MCP-1 production was up-regulated by exposure to hyperoxic conditions in both young (62 +/- 8, 99 +/- 7, 102 +/- 8 pg/ml, respectively) and aged rats (79 +/- 4, 112 +/- 9, 117 +/- 10 pg/ ml, respectively). We conclude that hyperoxia is an important regulator of MCP-1 release and support the hypothesis that increased % of O2 may serve to initiate MCP-1 production which then serves to recruit and regulate the distribution of mononuclear cells to the sites of inflammation.
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PMID:Oxygen supply modulates MCP-1 release in monocytes from young and aged rats: decrease of MCP-1 transcription and translation is age-related. 1287 Jun 48

Fibulin-5, previously known as DANCE and EVEC, is a secreted extracellular matrix protein that functions as a scaffold for elastin fiber assembly and as a ligand for integrins alphavbeta3, alphavbeta5, and alpha9beta1. Fibulin-5 is developmentally regulated in the lung, and lung air space enlargement develops in mice deficient in fibulin-5. Fibulin-5 is also induced in adult lung following lung injury by hyperoxia. To further examine the role of fibulin-5 during repair of lung injury, we assessed fibulin-5 expression during elastase-induced emphysema in C57/b mice. Mice were treated with either saline or elastase via the trachea, and the lung was examined 20 days after treatment. Fibulin-5 mRNA was induced almost fourfold, whereas elastin mRNA was minimally elevated. Immunohistochemistry studies showed that fibulin-5 was induced in cells within the alveolar wall following elastase treatment. Western analysis demonstrates that fibulin-5 was strongly expressed in isolated primary lung interstitial fibroblasts. Fibulin-5 protein was localized to the fibroblast cell layer in culture, and brief elastase treatment degraded the protein. Intact fibulin-5 did not accumulate in the culture media. Treatment of fibroblasts with the proinflammatory cytokine interleukin-1beta abolished fibulin-5 mRNA expression. Our results indicate that fibulin-5 is coordinately expressed and regulated with elastin in lung fibroblasts and may serve a key role during lung injury and repair.
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PMID:Coordinate expression of fibulin-5/DANCE and elastin during lung injury repair. 1290 85

Hyperbaric oxygen (HBO) is 100% oxygen administered at elevated atmospheric pressure to patients with inflammatory diseases. We developed an in vitro model to investigate the effects of HBO on stimulus-induced proinflammatory cytokine transcription and translation. Human blood-derived monocyte-macrophages were stimulated before being transferred to an HBO chamber where they were incubated at 97.9% O2, 2.1% CO2, 2.4 atmospheres absolute, 37 degrees C. Controls were maintained in the same warm room at normoxia at sea level, hyperoxia or increased pressure alone. A 90-min HBO exposure inhibited IL-1beta synthesized in response to lipopolysaccharide by 23%, lipid A by 45%, phytohaemagglutinin A (PHA) by 68%, and tumour necrosis factor (TNF)-alpha by 27%. HBO suppressed lipopolysaccharide-, lipid A- and PHA-induced TNF-alpha by 29%, 31% and 62%, respectively. HBO transiently reduced PHA-induced steady state IL-1beta mRNA levels. Hyperoxia alone and pressure alone did not affect cytokine production. The immunosuppressive effect of HBO was no longer evident in monocyte-macrophages exposed to HBO for more than 3 h. Interestingly, cells exposed to HBO for 12 h synthesized more IL-1beta than cells cultured under control conditions. In summary, HBO exposure transiently suppresses stimulus-induced proinflammatory cytokine production and steady state RNA levels.
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PMID:Hyperbaric oxygen inhibits stimulus-induced proinflammatory cytokine synthesis by human blood-derived monocyte-macrophages. 1297 55

During respiratory cycles, airborne particles and pathogens are inhaled into the lung, which can cause cytokine production by respiratory macrophages and inflammatory responses. Secreted cytokines affect surfactant protein expression and homeostasis in the lung. In coculturing experiments in vitro, bronchoalveolar macrophages stimulated human surfactant protein B (hSP-B) gene transcription in primary alveolar type II epithelial cells in lipopolysaccharide-independent and -dependent ways. Neutralization by IL-6 antibody abolished lipopolysaccharide-dependent macrophage stimulation of hSP-B gene transcription. IL-6 treatment enhanced signal transducer and activator of transcription (Stat)3 phosphorylation at Y705 in alveolar type II epithelial cells and Clara cells in vivo. Biochemical analysis of functional domain swapping between Stat1 and Stat3 identified that the SH2 domain and the DNA binding domain are critical for Stat3 stimulation of hSP-B gene transcription. Glutathione-S-transferase pull-down study determined functional domains required for protein-protein interaction between Stat3 and retinoic acid receptor-alpha. Cotransfection of Stat3 and retinoic acid receptor-alpha into respiratory epithelial cells resulted in synergistic DNA binding and transcriptional activation on the hSP-B gene. To assess Stat3 physiological function, overexpression of a dominant negative Stat3 in respiratory epithelial cells in a doxycycline-controlled double transgenic mouse line caused pulmonary emphysema and increase of animal death during hyperoxia. Therefore, the IL-6/Stat3 signaling axis plays an important role in surfactant protein homeostasis and respiratory inflammation in the lung.
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PMID:Synergy between signal transducer and activator of transcription 3 and retinoic acid receptor-alpha in regulation of the surfactant protein B gene in the lung. 1504 88

The response of the fetal rat Type II pneumocyte (FTIIP), the stem cell of the alveolar epithelium, to hyperoxia would be helpful to understand the effects of oxygen-induced injury to the developing lung. Our goals were to evaluate the effect of antioxidants (AO) on apoptosis and release of cytokines in freshly isolated FTIIP (day-19) in the presence of 95% O2 and/or nitric oxide (NO). There was increased apoptosis in FTIIP exposed to hyperoxia alone and in combination with NO; this was significantly attenuated (p < 0.01) in the presence of 3 AO, namely grape seed proanthocyanidin extract (GSPE), superoxide dismutase (SOD) and catalase. The anti-inflammatory cytokine IL-10 has been shown to have a role in ameliorating tissue damage owing to persistent inflammation. The release of IL-10 was significantly decreased (p < 0.01) in the presence of GSPE and catalase, compared to control. Addition of SOD led to increased IL-10 compared to GSPE or catalase (p < 0.01) or the combination of GSPE + SOD + catalase (p < or = 0.01). Thus, in our in vitro model of hyperoxic and NO mediated injury to FTIIP, protection from apoptotic cell death with the addition of AO was associated with varying levels of IL-10 release. Our data suggest that the use of SOD and/or IL-10 may decrease hyperoxic lung injury by decreasing apoptosis. Further studies are needed to understand the mode of protection from catalase and GSPE.
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PMID:Effect of antioxidants on apoptosis and cytokine release in fetal rat Type II pneumocytes exposed to hyperoxia and nitric oxide. 1534 20

The lungs of newborn rats exposed to 60% oxygen for 14 days develop an injury that shares morphologic similarities to human bronchopulmonary dysplasia (BPD). Neutrophil influx into the lung, as part of an inflammatory response, may play a pivotal role in the development of BPD. A neutrophil chemokine, cytokine-induced neutrophil chemoattractant-1, which signals through the neutrophil CXC chemokine receptor-2, is increased in the lung tissue of newborn rats exposed to 60% oxygen. The purpose of this study was to explore the role of neutrophils in the rat model of BPD by inhibiting neutrophil influx using SB265610, a selective CXC chemokine receptor-2 antagonist. SB265610, administered to 60% oxygen-exposed newborn rats from birth to 14 days, completely inhibited neutrophil influx. It also attenuated increased production of reactive oxygen species in newborn rat lung tissue after exposure to 60% oxygen for 4 days. Lung morphometric analysis revealed that 60% oxygen for 14 days, when accompanied by treatment with SB265610 to prevent neutrophil accumulation, increased alveolar formation over that seen in newborn rats exposed to air. These data suggest that exposure of the neonatal lung to moderate hyperoxia may enhance postnatal lung growth, provided postnatal pulmonary inflammation is suppressed.
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PMID:Opposing effects of 60% oxygen and neutrophil influx on alveologenesis in the neonatal rat. 1534 60

The present study was undertaken to test whether inhibition of the proangiogenic inflammatory cytokine tumor necrosis factor (TNF)-alpha can modulate retinal hypoxia and preretinal neovascularization in a murine model of oxygen-induced retinopathy (OIR). OIR was produced in TNF-alpha-/- and wild-type (WT) control C57B6 neonatal mice by exposure to 75% oxygen between postnatal days 7 and 12 (P7 to P12). Half of each WT litter was treated with the cytokine inhibitor semapimod (formerly known as CNI-1493) (5 mg/kg) by daily intraperitoneal injection from the time of reintroduction to room air at P12 until P17. The extent of preretinal neovascularization and intraretinal revascularization was quantified by image analysis of retinal flat-mounts and retinal hypoxia correlated with vascularization by immunofluorescent localization of the hypoxia-sensitive drug pimonidazole (hypoxyprobe, HP). HP adducts were also characterized by Western analysis and quantified by competitive enzyme-linked immunosorbent assay. TNF-alpha-/- and WT mice showed a similar sensitivity to hyperoxia-induced retinal ischemia at P12. At P13 some delay in early reperfusion was evident in TNF-alpha-/- and WT mice treated with semapimod. However, at P17 both these groups had significantly better vascular recovery with less ischemic/hypoxic retina and preretinal neovascularization compared to untreated retinopathy in WT mice. Immunohistochemistry showed deposition of HP in the avascular inner retina but not in areas underlying preretinal neovascularization, indicating that such aberrant vasculature can reduce retinal hypoxia. Inhibition of TNF-alpha significantly improves vascular recovery within ischemic tissue and reduces pathological neovascularization in OIR. HP provides a useful tool for mapping and quantifying tissue hypoxia in experimental ischemic retinopathy.
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PMID:Inhibition of tumor necrosis factor-alpha improves physiological angiogenesis and reduces pathological neovascularization in ischemic retinopathy. 1568 45

Acute lung injury after acid aspiration and increased ambient oxygen result in significant oxidative damage to the lungs. Lung antioxidant levels are also reduced. Because levels of serine proteinases in the airspaces are also dramatically increased, we hypothesized that these enzymes play a role in degrading lung antioxidants. Rats were treated with a serine proteinase inhibitor, aprotinin, before pulmonary aspiration of acid in the presence of increased ambient oxygen (hyperoxia). Lung Cu/Zn and Mn superoxide dismutase (SOD) activity (by colorimetric assay) and Cu/Zn SOD immune reactive protein (enzyme-linked immunosorbent assay) were assayed. The effects of antiproteinase treatment on acute lung injury were also assessed. Total SOD, Cu/Zn SOD, and Cu/Zn SOD antigenic protein levels were decreased in animals after acid aspiration and hyperoxia. However, Mn SOD activity was unchanged. The decrease in Cu/Zn SOD was attenuated in animals, where serine proteinase activity was inhibited. However, antiproteinase treatment did not decrease acute pulmonary injury, as assessed by leakage of radiolabeled albumin into the lung (permeability index), arterial blood gases, and markers of acute inflammation (pulmonary myeloperoxidase activity, a surrogate neutrophilic marker, and inflammatory cytokine profiles). We conclude that production of serine proteinases play a major role in degrading Cu/Zn SOD, thereby decreasing pulmonary antioxidant capacity. However, the role this plays in the pathogenesis of the acute lung injury is not clear.
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PMID:Serine antiproteinase administration preserves innate superoxide dismutase levels after acid aspiration and hyperoxia but does not decrease lung injury. 1597 34

Cytokines are peptides that are produced by virtually every nucleated cell type in the body, possess overlapping biological activities, exert different effects at different concentrations, can either synergize or antagonize the effects of other cytokines, are regulated in a complex manner, and function via cytokine cascades. Hyperoxia-induced acute lung injury (HALI) is characterized by an influx of inflammatory cells, increased pulmonary permeability, and endothelial and epithelial cell injury/death. Some of these effects are orchestrated by cytokines. There are significant differences in the response of the developing versus the adult lung to hyperoxia. We review here cytokines (and select growth factors) that are involved in tolerance toward HALI in animal models. Increased cytokine expression and release have a cascade effect in HALI. IL-1 precedes the increase in IL-6 and CINC-1/IL-8 and this seems to predate the influx of inflammatory cells. Inflammatory cells in the alveolar space amplify the lung damage. Other cytokines that are primarily involved in this inflammatory response include IFN-gamma, MCP-1, and MIP-2. Certain cytokines (and growth factors) seem to ameliorate HALI by affecting cell death pathways. These include GM-CSF, KGF, IL-11, IL-13, and VEGF. There are significant differences in the type and temporal sequence of cytokine expression and release in the adult and newborn lung in response to hyperoxia. The newborn lung is greatly resistant to hyperoxia compared to the adult. The delayed increase in lung IL-1 and IL-6 in the newborn could induce protective factors that would help in the resolution of hyperoxia-induced injury. Designing a therapeutic approach to counteract oxygen toxicity in the adult and immature lung first needs understanding of the unique responses in each scenario.
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PMID:Cytokines in tolerance to hyperoxia-induced injury in the developing and adult lung. 1678 48

We have previously demonstrated that mice exposed to sublethal hyperoxia (an atmosphere of >95% oxygen for 4 days, followed by return to room air) have significantly impaired pulmonary innate immune response. Alveolar macrophages (AM) from hyperoxia-exposed mice exhibit significantly diminished antimicrobial activity and markedly reduced production of inflammatory cytokines in response to stimulation with LPS compared with AM from control mice in normoxia. As a consequence of these defects, mice exposed to sublethal hyperoxia are more susceptible to lethal pneumonia with Klebsiella pneumoniae than control mice. Granulocyte/macrophage colony-stimulating factor (GM-CSF) is a growth factor produced by normal pulmonary alveolar epithelial cells that is critically involved in maintenance of normal AM function. We now report that sublethal hyperoxia in vivo leads to greatly reduced alveolar epithelial cell GM-CSF expression. Systemic treatment of mice with recombinant murine GM-CSF during hyperoxia exposure preserved AM function, as indicated by cell surface Toll-like receptor 4 expression and by inflammatory cytokine secretion following stimulation with LPS ex vivo. Treatment of hyperoxic mice with GM-CSF significantly reduced lung bacterial burden following intratracheal inoculation with K. pneumoniae, returning lung bacterial colony-forming units to the level of normoxic controls. These data point to a critical role for continuous GM-CSF activity in the lung in maintenance of normal AM function and demonstrate that lung injury due to hyperoxic stress results in significant impairment in pulmonary innate immunity through suppression of alveolar epithelial cell GM-CSF expression.
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PMID:GM-CSF and the impaired pulmonary innate immune response following hyperoxic stress. 1689 99


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