Melatonin receptor agonist protects against acute lung injury induced by ventilator through up-regulation of IL-10 production.

BACKGROUND: It is well known that ventilation with high volume or pressure may damage healthy lungs or worsen injured lungs. Melatonin has been reported to be effective in animal models of acute lung injury. Melatonin exerts its beneficial effects by acting as a direct antioxidant and via melatonin receptor activation. However, it is not clear whether melatonin receptor agonist has a protective effect in ventilator-induced lung injury (VILI). Therefore, in this study, we determined whether ramelteon (a melatonin receptor agonist) can attenuate VILI and explore the possible mechanism for protection. METHODS: VILI was induced by high tidal volume ventilation in a rat model. The rats were randomly allotted into the following groups: control, control+melatonin, control+ramelteon, control+luzindole, VILI, VILI+luzindole, VILI + melatonin, VILI + melatonin + luzindole (melatonin receptor antagonist), VILI + ramelteon, and VILI + ramelteon + luzindole (n = 6 per group). The role of interleukin-10 (IL-10) in the melatonin- or ramelteon-mediated protection against VILI was also investigated. RESULTS: Ramelteon treatment markedly reduced lung edema, serum malondialdehyde levels, the concentration of inflammatory cytokines in bronchoalveolar lavage fluid (BALF), NF-κB activation, iNOS levels, and apoptosis in the lung tissue. Additionally, ramelteon treatment significantly increased heat shock protein 70 expression in the lung tissue and IL-10 levels in BALF. The protective effect of ramelteon was mitigated by the administration of luzindole or an anti-IL-10 antibody. CONCLUSIONS: Our results suggest that a melatonin receptor agonist has a protective effect against VILI, and its protective mechanism is based on the upregulation of IL-10 production.

Correction: Wen-I Liao, et al. Ac2-26, an Annexin A1 Peptide, Attenuates Ischemia-Reperfusion-Induced Acute Lung Injury. Int. J. Mol. Sci. 2017, 18, 1771.

The authors would like to make a correction to their published paper [1][...].

Targeting of nicotinamide phosphoribosyltransferase enzymatic activity ameliorates lung damage induced by ischemia/reperfusion in rats.

BACKGROUND: Emerging evidence reveals that nicotinamide phosphoribosyltransferase (NAMPT) has a significant role in the pathophysiology of the inflammatory process. NAMPT inhibition has a beneficial effect in the treatment of a variety of inflammatory diseases. However, it remains unclear whether NAMPT inhibition has an impact on ischemia-reperfusion (I/R)-induced acute lung injury. In this study, we examined whether NAMPT inhibition provided protection against I/R lung injury in rats. METHODS: Isolated perfused rat lungs were subjected to 40 min of ischemia followed by 60 min of reperfusion. The rats were randomly allotted to the control, control + FK866 (NAMPT inhibitor, 10 mg/kg), I/R, or I/R + FK866 groups (n = 6 per group). The effects of FK866 on human alveolar epithelial cells exposed to hypoxia-reoxygenation (H/R) were also investigated. RESULTS: Treatment with FK866 significantly attenuated the increases in lung edema, pulmonary arterial pressure, lung injury scores, and TNF-α, CINC-1, and IL-6 concentrations in bronchoalveolar lavage fluid in the I/R group. Malondialdehyde levels, carbonyl contents and MPO-positive cells in lung tissue were also significantly reduced by FK866. Additionally, FK866 mitigated I/R-stimulated degradation of IκB-α, nuclear translocation of NF-κB, Akt phosphorylation, activation of mitogen-activated protein kinase, and downregulated MKP-1 activity in the injured lung tissue. Furthermore, FK866 increased Bcl-2 and decreased caspase-3 activity in the I/R rat lungs. Comparably, the in vitro experiments showed that FK866 also inhibited IL-8 production and NF-κB activation in human alveolar epithelial cells exposed to H/R. CONCLUSIONS: Our findings suggest that NAMPT inhibition may be a novel therapeutic approach for I/R-induced lung injury. The protective effects involve the suppression of multiple signal pathways.

Ac2-26, an Annexin A1 Peptide, Attenuates Ischemia-Reperfusion-Induced Acute Lung Injury.

Annexin A1 (AnxA1) is an endogenous protein that modulates anti-inflammatory processes, and its therapeutic potential has been reported in a range of inflammatory diseases. The effect of AnxA1 on ischemia-reperfusion (IR)-induced lung injury has not been examined. In this study, isolated, perfused rat lungs were subjected to IR lung injury induced by ischemia for 40 min, followed by reperfusion for 60 min. The rat lungs were randomly treated with vehicle (phosphate-buffered saline), and Ac2-26 (an active N-terminal peptide of AnxA1) with or without an N-formyl peptide receptor (FPR) antagonist N-Boc-Phe-Leu-Phe-Leu-Phe (Boc2). An in vitro study of the effects of Ac2-26 on human alveolar epithelial cells subjected to hypoxia-reoxygenation was also investigated. Administration of Ac2-26 in IR lung injury produced a significant attenuation of lung edema, pro-inflammatory cytokine production recovered in bronchoalveolar lavage fluid, oxidative stress, apoptosis, neutrophil infiltration, and lung tissue injury. Ac2-26 also decreased AnxA1 protein expression, inhibited the activation of nuclear factor-κB and mitogen-activated protein kinase pathways in the injured lung tissue. Finally, treatment with Boc2 abolished the protective action of Ac2-26. The results indicated that Ac2-26 had a protective effect against acute lung injury induced by IR, which may be via the activation of the FPR.

Valproic acid attenuates acute lung injury induced by ischemia-reperfusion in rats.

BACKGROUND: Evidence reveals that histone deacetylase (HDAC) inhibition has potential for the treatment of inflammatory diseases. The protective effect of HDAC inhibition involves multiple mechanisms. Heme oxygenase-1 (HO-1) is protective in lung injury as a key regulator of antioxidant response. The authors examined whether HDAC inhibition provided protection against ischemia-reperfusion (I/R) lung injury in rats by up-regulating HO-1 activity. METHODS: Acute lung injury was induced by producing 40 min of ischemia followed by 60 min of reperfusion in isolated perfused rat lungs. The rats were randomly allotted to control group, I/R group, or I/R + valproic acid (VPA) group with or without an HO-1 activity inhibitor (zinc protoporphyrin IX) (n = 6 per group). RESULTS: I/R caused significant increases in the lung edema, pulmonary arterial pressure, lung injury scores, tumor necrosis factor-α, and cytokine-induced neutrophil chemoattractant-1 concentrations in bronchoalveolar lavage fluid. Malondialdehyde levels, carbonyl contents, and myeloperoxidase-positive cells in lung tissue were also significantly increased. I/R stimulated the degradation of inhibitor of nuclear factor-κB-α, nuclear translocation of nuclear factor-κB, and up-regulation of HO-1 activity. Furthermore, I/R decreased B-cell lymphoma-2, heat shock protein 70, acetylated histone H3 protein expression, and increased the caspase-3 activity in the rat lungs. In contrast, VPA treatment significantly attenuated all the parameters of lung injury, oxidative stress, apoptosis, and inflammation. In addition, VPA treatment also enhanced HO-1 activity. Treatment with zinc protoporphyrin IX blocked the protective effect of VPA. CONCLUSIONS: VPA protected against I/R-induced lung injury. The protective mechanism may be partly due to enhanced HO-1 activity following HDAC inhibition.

Risk factors for the development of pulmonary oil embolism after transcatheter arterial chemoembolization of hepatic tumors.

Pulmonary oil embolism (POE) is a rare fatal complication after transcatheter arterial embolization (TAE) and transcatheter arterial chemoembolization (TACE). As risk factors have not been clearly delineated, the aim of the present study was to identify the risk factors for development of POE after TACE. A retrospective analysis was carried out on patients with unresectable hepatocellular carcinoma who received TAE or TACE at the Tri-Service General Hospital (Taiwan) between January 2005 and December 2008. The diagnosis of TAE-induced or TACE-induced POE was based on development of respiratory signs and symptoms relatively soon after the procedure, as well as based on characteristic radiographic findings. Of the 219 enrolled patients in this study, 20 were diagnosed with POE after TAE or TACE. On univariate logistic regression analysis, patients developing POE were found to be older (67.95±15.95 vs. 61.44±12.59 years, P=0.033), with a lower serum albumin level (3.25±0.58 vs. 3.62±0.57 g/dl, P=0.009), a higher grade of liver cirrhosis as classified on the basis of Child's criteria (P<0.006), a larger tumor size (8.55±4.52 vs. 4.78±3.97 cm in diameter, P<0.001), a higher lipioidol dose (22.35±11.01 vs. 13.69±7.66 ml, P=0.003), and a higher doxorubicin dose (50.27±7.05 vs. 40.75±13.61 mg, P<0.001). Following multivariate logistic regression analysis, only lipiodol dose was found to be a significant risk factor for POE (odds ratio=1.133, 95% confidence interval: 1.004, 1.279; P=0.044). The receiver operator characteristic curve cutoff point for lipiodol dose level was 14.5 ml, with a sensitivity of 80% and a specificity of 66.3%. In conclusion, the lipiodol dose could be considered as a predictive factor for POE after TAE or TACE in hepatic malignant tumor patients. On the basis of this retrospective study, the safe lipiodol dose to minimize the risk for POE is 14.5 ml or lower; however, larger, prospective studies are needed to determine the optimally safe and yet efficacious dose.

Extraction of large foreign bodies from the airway by gastrointestinal endoscopy.

Foreign body aspiration is a worldwide health problem that often results in life-threatening complications. Although flexible bronchoscopy is a safe procedure for removal of foreign bodies, it is usually unsuccessful in removing large foreign bodies from the airway. Gastrointestinal (GI) endoscopy, which is frequently used to remove foreign bodies from the gastrointestinal tract, has not been reported for retrieval of airway foreign bodies. In this report, we described three successful cases of removal of large airway foreign bodies by GI endoscopy. To avoid rigid bronchoscopy, GI endoscopy can be considered if flexible bronchoscopy has failed to remove a large or heavy airway foreign body in adult patients.

Experimental chronic kidney disease attenuates ischemia-reperfusion injury in an ex vivo rat lung model.

Lung ischemia reperfusion injury (LIRI) is one of important complications following lung transplant and cardiopulmonary bypass. Although patients on hemodialysis are still excluded as lung transplant donors because of the possible effects of renal failure on the lungs, increased organ demand has led us to evaluate the influence of chronic kidney disease (CKD) on LIRI. A CKD model was induced by feeding Sprague-Dawley rats an adenine-rich (0.75%) diet for 2, 4 and 6 weeks, and an isolated rat lung in situ model was used to evaluate ischemia reperfusion (IR)-induced acute lung injury. The clinicopathological parameters of LIRI, including pulmonary edema, lipid peroxidation, histopathological changes, immunohistochemistry changes, chemokine CXCL1, inducible nitric oxide synthase (iNOS), proinflammatory and anti-inflammatory cytokines, heat shock protein expression, and nuclear factor-κB (NF-κB) activation were determined. Our results indicated that adenine-fed rats developed CKD as characterized by increased blood urea nitrogen and creatinine levels and the deposition of crystals in the renal tubules and interstitium. IR induced a significant increase in the pulmonary arterial pressure, lung edema, lung injury scores, the expression of CXCL1 mRNA, iNOS level, and protein concentration of the bronchial alveolar lavage fluid (BALF). The tumor necrosis factor-α levels in the BALF and perfusate; the interleukin-10 level in the perfusate; and the malondialdehyde levels in the lung tissue and perfusate were also significantly increased by LIRI. Counterintuitively, adenine-induced CKD significantly attenuated the severity of lung injury induced by IR. CKD rats exhibited increased heat shock protein 70 expression and decreased activation of NF-κB signaling. In conclusion, adenine-induced CKD attenuated LIRI by inhibiting the NF-κB pathway.

Protection against reperfusion lung injury via aborgating multiple signaling cascades by trichostatin A.

Trichostatin A (TSA) is a histone deacetylase inhibitor with anti-inflammatory effects. Nonetheless, little information is available about the effect of TSA in ischemia-reperfusion (IR)-induced lung injury. In a perfused rat lung model, IR was induced by 40min of ischemia followed by 60min of reperfusion. The rat lungs were randomly divided into several groups including control, control+TSA (0.1mg/kg), IR, and IR+various dosages of TSA (0.05, 0.075, 0.1mg/kg). Bronchoalveolar lavage fluids and lung tissues were obtained and examined at the end of the experiment. TSA dose-dependently diminished IR-induced increased vascular permeability and edema, pulmonary artery pressure, and histological changes in the lungs. Additionally, TSA suppressed lavage tumor necrosis factor-α and cytokine-induced neutrophil chemoattractant concentrations, cell infiltration, and myeloperoxidase-positive cells in the lung tissue. Furthermore, TSA attenuated the phosphorylation of extracellular signal-regulated kinase, p38, and c-Jun N-terminal kinase, degradation of the inhibitor of nuclear factor (NF)-κB, and nuclear NF-κB levels. TSA also decreased poly (ADP-ribose) polymerase but enhanced acetylated histone H3 acetylation, Bcl-2, and mitogen-activated protein kinase phosphatase-1 (MKP-1) expression in IR lung tissue. Therefore, TSA exerted a protective effect on IR-induced lung injury via increasing histone acetylation and MKP-1 protein expression, repressing NF-κB, mitogen-activated protein kinase, and apoptosis signaling pathways.

Protective effect of hypercapnic acidosis in ischemia-reperfusion lung injury is attributable to upregulation of heme oxygenase-1.

Hypercapnic acidosis (HCA) has protective effects in animal models of acute lung injury, but the mechanism underlying the effect of HCA is unclear. Heme oxygenase-1 (HO-1) is an antioxidant enzyme that protects tissue from inflammation injury. We investigated whether HO-1 contributes to the protective effects of HCA in ischemia-reperfusion (IR)-induced lung injury. Typical acute lung injury in rats was successfully induced by 40 min of ischemia and 90 min of reperfusion in an isolated perfused lung model. The rat lungs were randomly assigned to the control group, IR group or IR + HCA group with or without zinc protoporphyrin IX (ZnPP), an HO-1 activity inhibitor. At the end of the experiment, bronchoalveolar lavage fluid (BALF) and lung tissues were collected to evaluate the degree of lung injury. In in vitro experiments, HO-1 siRNA transfected A549 cells were exposed to a normoxic or hypoxia-reoxygenation (H/R) environment in the presence or absence of HCA. IR caused significant increases in the pulmonary arterial pressure, lung weight to body weight and wet/dry ratios, lung weight gain, capillary filtration coefficient, lung injury scores, neutrophil infiltration, and concentrations of protein and TNF-α in the BALF. IR also induced degradation of inhibitor of nuclear factor (NF)-κB-α, increased IκB kinase (IKK)-ß phosphorylation and nuclear translocation of NF-κB, and up-regulated HO-1 expression and activity. Furthermore, IR decreased Bcl-2 protein expression and increased the number of active caspase-3 stained cells. HCA treatment enhanced HO-1 expression and activity, and accordingly reduced IKK-NF-κB signaling, inhibited apoptosis, and significantly attenuated IR-induced changes. Treatment with ZnPP partially blocked the protective effect of HCA. In addition, HO-1 siRNA significantly reversed HCA-mediated inhibition of NF-κB signaling in A549 cells subjected to H/R. In conclusion, the protective effect of HCA in IR lung injury in rats was mediated in part by the anti-inflammatory and anti-apoptotic action of HO-1.

Systemic administration of FC-77 dampens ischemia-reperfusion-induced acute lung injury in rats.

Systemic administration of perfluorocarbons (PFCs) reportedly attenuates acute lung injury induced by acid aspiration and phorbol myristate acetate. However, the effects of PFCs on ischemia-reperfusion (IR)-induced lung injury have not been investigated. Typical acute lung injury was induced in rats by 60 min of ischemia and 60 min of reperfusion in isolated and perfused rat lung model. Rat lungs were randomly assigned to receive PBS (control), 1 % FC-77, IR only, or IR with different doses of FC-77 (0.1 %, 0.5 %, or 1 %). Subsequently, bronchoalveolar lavage fluid (BALF), perfusate, and lung tissues were collected to evaluate the degree of lung injury. IR caused a significant increase in the following parameters: pulmonary arterial pressure, capillary filtration coefficient, lung weight gain, lung weight/body weight ratio, wet/dry lung weight ratio, and protein concentration in BALF. TNF-α and cytokine-induced neutrophil chemoattractant-1 concentrations in perfusate samples and MDA concentration and MPO activities in lung tissues were also significantly increased. Histopathology showed increased septal thickness and neutrophil infiltration in the lung tissues. Furthermore, NF-κB activity was significantly increased in the lungs. However, pretreatment with 1 % FC-77 prior to IR significantly attenuated the increases in these parameters. In conclusion, our results suggest that systemic FC-77 administration had a protective effect on IR-induced acute lung injury. These protective mechanisms may have been mediated by the inhibition of NF-κB activation and attenuation of subsequent inflammatory response.

Acute respiratory distress syndrome after transcatheter arterial chemoembolization of hepatocellular carcinomas.

BACKGROUND: Acute respiratory distress syndrome (ARDS) associated with pulmonary lipiodol embolism is a rare complication of transcatheter arterial chemoembolization (TACE). We performed a survey of ARDS associated with pulmonary lipiodol embolism after TACE. METHODS: A retrospective analysis of the cases of all patients with hepatic tumors who received transcatheter arterial embolization or TACE between January 2006 and December 2006 was performed. The diagnosis of pulmonary lipiodol embolism was confirmed by chest computed tomography (CT). RESULTS: The diagnosis of ARDS associated with pulmonary lipiodol embolism was confirmed in 4 patients. All had large (> or =5 cm) and hypervascular tumors. There was no evidence of hepatocellular carcinoma arteriovenous shunting in any of our patients as determined by angiography and multidetector CT. The volumes of lipiodol infused in the 4 patients were 50, 20, 30, and 20 mL. Only 2 patients received injections of carcinostatic agents. The onset of respiratory symptoms occurred between 1 hour and 4 days after TACE. Respiratory symptoms consisted of dyspnea and tachypnea. Chest CT scans revealed linear high-density shadows, suggestive of lipiodol retention in both lungs of all patients. CONCLUSION: Pulmonary lipiodol embolism after TACE can occur within a short time frame. Whether or not there is intrahepatic arteriovenous shunting detected by multidetector CT and angiography, clinicians should avoid high doses of iodized oil and carcinostatic agents. We suggest that CT should be used for the diagnosis of pulmonary lipiodol embolism.