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Dexamethasone inhibits endotoxin-induced coagulopathy in human lungs.

ABSTRACT: Essentials Glucocorticoids are associated with an increased risk of thrombosis. Healthy volunteers received dexamethasone or placebo in an endotoxin lung instillation model. Dexamethasone suppressed thrombin generation in bronchoalveolar lavage. Glucocorticoids inhibit endotoxin induced pulmonary coagulopathy. SUMMARY:Background Activation of local and systemic coagulation is a common finding in patients with pneumonia. There is evidence that glucocorticoids have procoagulant activity in the circulation, particularly in the context of inflammation. The effects of glucocorticoids on local pulmonary coagulation have not yet been investigated. Objective To use a human model of lung inflammation based on the local instillation of endotoxin in order to investigate whether glucocorticoids alter pulmonary coagulation. Methods Twenty-four healthy volunteers were randomized to receive either dexamethasone or placebo in a double-blind trial. Endotoxin was instilled via bronchoscope into right or left lung segments, followed by saline into the contralateral site. Six hours later, a bilateral bronchoalveolar lavage (BAL) was performed and coagulation parameters were measured. Results Endotoxin induced activation of coagulation in the bronchoalveolar compartment: the level of prothrombin fragment 1 + 2 (F1 + 2 ) was increased three-fold (248 pmol L-1 , 95% confidence interval [CI] 43-454 versus 743 pmol L-1 , 95% CI 437-1050) and the level of thrombin-antithrombin complex (TATc) was increased by ~ 50% (31 ?g L-1 , 95% CI 18-45 versus 49 ?g L-1 , 95% CI 36-61) as compared with saline-challenged segments. Dexamethasone reduced F1 + 2 (284 pmol L-1 , 95% CI 34-534) and TATc (9 ?g L-1 , 95% CI 0.7-17) levels almost to those measured in BAL fluid from the saline-instilled segments in the placebo group. Dexamethasone even profoundly reduced F1 + 2 levels (80%) in saline-instilled lung segments (50 pmol L-1 , 95% CI 12-87). In contrast, dexamethasone had no effect on systemic F1 + 2 levels. Conclusions Dexamethasone inhibits endotoxin-induced coagulopathy in lungs. This trial is the first to provide insights into the effects of glucocorticoids on pulmonary coagulation in response to endotoxin.

SUBMITTER: Bartko J

PROVIDER: S-EPMC5298044 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature

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Dexamethasone inhibits endotoxin-induced coagulopathy in human lungs.

Bartko J J Schoergenhofer C C Schwameis M M Buchtele N N Wojta J J Schabbauer G G Stiebellehner L L Jilma B B

Journal of thrombosis and haemostasis : JTH 20161024 12

Essentials Glucocorticoids are associated with an increased risk of thrombosis. Healthy volunteers received dexamethasone or placebo in an endotoxin lung instillation model. Dexamethasone suppressed thrombin generation in bronchoalveolar lavage. Glucocorticoids inhibit endotoxin induced pulmonary coagulopathy.<h4>Summary</h4>Background Activation of local and systemic coagulation is a common finding in patients with pneumonia. There is evidence that glucocorticoids have procoagulant activity in ...[more]

PMID: 27622544

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Project description:BackgroundBone marrow-derived fibrocytes reportedly play important roles in the pathogenesis of idiopathic pulmonary fibrosis. Pirfenidone is an anti-fibrotic agent; however, its effects on fibrocytes have not been investigated. The aim of this study was to investigate whether pirfenidone inhibits fibrocyte pool size in the lungs of bleomycin-treated mice.MethodsBleomycin (100 mg/kg) was infused with osmotic pumps into C57BL/6 mice, and pirfenidone (300 mg/kg/day) was orally administered daily for 2 wk. The lungs were removed, and single-cell suspensions were subjected to fluorescence-activated cell sorter (FACS) analysis to detect fibrocytes, which were defined as CD45 and collagen-I double-positive cells. Immunohistochemistry was performed on the lung specimens to quantify fibrocytes. Chemokines in the lung digests were measured with enzyme-linked immunosorbent assay. The effect of pirfenidone on alveolar macrophages was evaluated with bronchoalveolar lavage (BAL). In a therapeutic setting, pirfenidone administration was initiated 10 days after bleomycin treatment. For chemotaxis assay, lung fibrocytes were isolated with immunomagnetic selection (CD45-positive mesenchymal cells) after culture and allowed to migrate toward chemokines in the presence or absence of pirfenidone. Moreover, the effect of pirfenidone on the expression of chemokine receptors on fibrocytes was evaluated.ResultsPirfenidone significantly ameliorated bleomycin-induced pulmonary fibrosis as assessed with quantitative histology and collagen measurement. Fibrocyte pool size in bleomycin-treated mice lungs was attenuated from 26.5% to 13.7% by pirfenidone on FACS analysis. This outcome was also observed in a therapeutic setting. Immunohistochemistry revealed that fibrocytes were significantly decreased by pirfenidone administration compared with those in bleomycin-treated mice (P = 0.0097). Increased chemokine (CC motif) ligand-2 (CCL2) and CCL12 production in bleomycin-treated mouse lungs was significantly attenuated by pirfenidone (P = 0.0003 and P < 0.0001, respectively). Pirfenidone also attenuated macrophage counts stimulated by bleomycin in BAL fluid. Fibrocyte migration toward CCL2 and chemokine (CC motif) receptor-2 expression on fibrocytes was significantly inhibited by pirfenidone in vitro.ConclusionsPirfenidone attenuated the fibrocyte pool size in bleomycin-treated mouse lungs via attenuation of CCL2 and CCL12 production in vivo, and fibrocyte migration was inhibited by pirfenidone in vitro. Fibrocyte inhibition is considered a mechanism of anti-fibrotic action of pirfenidone.

Project description:Viral infections of the airway can exacerbate respiratory diseases, such as asthma or chronic obstructive pulmonary disease (COPD), and accelerate disease progression. Phosphoinositide 3-kinase (PI3K)?, a class 1A PI3K, has been studied as a potential target for achieving anti-oncogenic and anti-inflammatory effects. However, the role of PI3K? in antiviral responses is poorly understood. Using a synthetic double-stranded RNA poly I:C and a selective PI3K? inhibitor IC87114, we investigated the role of PI3K? signaling in poly I:C-induced expression of the T lymphocyte-inhibitory molecule programmed death 1 ligand 1 (PD-L1), inflammatory responses and antiviral interferon (IFN) responses. C57BL/6N mice were treated with IC87114 or vehicle by intratracheal (i.t.) instillation followed by i.t. administration of poly I:C. Poly I:C increased PD-L1 expression on epithelial cells, lymphocytes, macrophages, and neutrophils in the lungs and IC87114 suppressed poly I:C-induced PD-L1 expression on epithelial cells and neutrophils possibly via inhibition of the Akt/mTOR signaling pathway. IC87114 also attenuated poly I:C-induced increases in numbers of total cells, macrophages, neutrophils and lymphocytes, as well as levels of KC, IL-6 and MIP-1? in bronchoalveolar lavage fluid. Gene expression of IFN?, IFN?2 and IFN-stimulated genes (ISGs) were upregulated in response to poly I:C and a further increase in gene expression was observed following IC87114 treatment. In addition, IC87114 enhanced poly I:C-induced phosphorylation of IRF3. We assessed the effects of IC87114 on human primary bronchial epithelial cells (PBECs). IC87114 decreased poly I:C-induced PD-L1 expression on PBECs and secretion of IL-6 and IL-8 into culture supernatants. IC87114 further enhanced poly I:C- induced increases in the concentrations of IFN? and IFN?1/3 in culture supernatants as well as upregulated gene expression of ISGs in PBECs. Similar results were obtained in PBECs transfected with siRNA targeting the PIK3CD gene encoding PI3K p110?, and stimulated with poly I:C. In human metapneumovirus (hMPV) infection of PBECs, IC87114 suppressed hMPV-induced PD-L1 expression and reduced viral replication without changing the production levels of IFN? and IFN?1/3 in culture supernatants. These data suggest that IC87114 may promote virus elimination and clearance through PD-L1 downregulation and enhanced antiviral IFN responses, preventing prolonged lung inflammation, which exacerbates asthma and COPD.

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Dexamethasone inhibits endotoxin-induced coagulopathy in human lungs.

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Dexamethasone inhibits endotoxin-induced coagulopathy in human lungs.

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