Biomarkers in acute lung injury

Shock Wave Therapy Enhances Mitochondrial Delivery into Target Cells and Protects against Acute Respiratory Distress Syndrome

This study tested the hypothesis that shock wave therapy (SW) enhances mitochondrial uptake into the lung epithelial and parenchymal cells to attenuate lung injury from acute respiratory distress syndrome (ARDS). ARDS was induced in rats through continuous inhalation of 100% oxygen for 48 h, while SW entailed application 0.15 mJ/mm² for 200 impulses at 6 Hz per left/right lung field. In vitro and ex vivo studies showed that SW enhances mitochondrial uptake into lung epithelial and parenchyma cells (all p < 0.001). Flow cytometry demonstrated that albumin levels and numbers of inflammatory cells (Ly6G+/CD14+/CD68+/CD11^b/c+) in bronchoalveolar lavage fluid were the highest in untreated ARDS, were progressively reduced across SW, Mito, and SW + Mito (all p < 0.0001), and were the lowest in sham controls. The same profile was also seen for fibrosis/collagen deposition, levels of biomarkers of oxidative stress (NOX-1/NOX-2/oxidized protein), inflammation (MMP-9/TNF-α/NF-κB/IL-1β/ICAM-1), apoptosis (cleaved caspase 3/PARP), fibrosis (Smad3/TGF-β), mitochondrial damage (cytosolic cytochrome c) (all p < 0.0001), and DNA damage (γ-H2AX+), and numbers of parenchymal inflammatory cells (CD11+/CD14+/CD40L+/F4/80+) (p < 0.0001). These results suggest that SW-assisted Mito therapy effectively protects the lung parenchyma from ARDS-induced injury.

MicroRNA-27a alleviates LPS-induced acute lung injury in mice via inhibiting inflammation and apoptosis through modulating TLR4/MyD88/NF-κB pathway

Acute lung injury (ALI) is a critical clinical condition with a high mortality rate, characterized with excessive uncontrolled inflammation and apoptosis. Recently, microRNAs (miRNAs) have been found to play crucial roles in the amelioration of various inflammation-induced diseases, including ALI. However, it remains unknown the biological function and regulatory mechanisms of miRNAs in the regulation of inflammation and apoptosis in ALI. The aim of this study is to identify and evaluate the potential role of miRNAs in ALI and reveal the underlying molecular mechanisms of their effects. Here, we analyzed microRNA expression profiles in lung tissues from LPS-challenged mice using miRNA microarray. Because microRNA-27a (miR-27a) was one of the miRNAs being most significantly downregulated, which has an important role in regulation of inflammation, we investigated its function. Overexpression of miR-27a by agomir-27a improved lung injury, as evidenced by the reduced histopathological changes, lung wet/dry (W/D) ratio, lung microvascular permeability and apoptosis in the lung tissues, as well as ameliorative survival of ALI mice. This was accompanied by the alleviating of inflammation, such as the reduced total BALF cell and neutrophil counts, decreased levels of tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-6) interleukin-1β (IL-1β) and myeloperoxidase (MPO) activity in BAL fluid. Toll-like receptor 4 (TLR4), an important regulator of the nuclear factor kappa-B (NF-κB) signaling pathway, was identified as a novel target of miR-27a in RAW264.7 cells. Furthermore, our results showed that LPS stimulation increased the expression of MyD88 and NF-κB p65 (p-p65), but inhibited the expression of inhibitor of nuclear factor-κB-α (IκB-α), suggesting the activation of NF-κB signaling pathway. Further investigations revealed that agomir-miR-27a reversed the promoting effect of LPS on NF-κB signaling pathway. The results here suggested that miR-27a alleviates LPS-induced ALI in mice via reducing inflammation and apoptosis through blocking TLR4/MyD88/NF-κB activation.

Alpinumisoflavone attenuates lipopolysaccharide-induced acute lung injury by regulating the effects of anti-oxidation and anti-inflammation both in vitro and in vivo

Alpinumisoflavone (AIF) is a plant-derived pyranoisoflavone that exhibits a number of pharmacological activities, but the protective effects of AIF against pulmonary inflammation are still unknown. This study aimed to investigate the anti-inflammatory effects and possible molecular mechanisms of AIF in both lipopolysaccharide (LPS)-stimulated macrophages and mice. The results revealed that AIF dramatically suppressed the production of pro-inflammatory mediators [including tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β, IL-17, intercellular adhesion molecule-1 (ICAM-1), and nitric oxide (NO)] and increased the levels of anti-oxidative enzymes [including catalase (CAT), heme oxygenase-1 (HO-1), glutathione peroxidase (GPx), and superoxide dismutase (SOD)] both in vitro and in vivo. Additionally, pre-treatment with AIF could not only significantly prevent histopathological changes and neutrophil infiltration but also decreased the expression levels of nuclear factor-kappa B (NF-κB), mitogen-activated protein kinases (MAPKs), and the nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome, as well as IL-17 production in LPS-induced lung tissues. The anti-inflammatory effects of AIF were mediated by up-regulating anti-oxidative enzymes and suppressing the NF-κB, MAPK, NLRP3 inflammasome and IL-17 signaling pathways. This is the first study to reveal that AIF has a protective effect against LPS-induced lung injury in mice.

Protective Effects of Neural Crest-Derived Stem Cell-Conditioned Media against Ischemia-Reperfusion-Induced Lung Injury in Rats

Current treatments for ischemia-reperfusion (IR)-induced acute lung injury are limited. Mesenchymal stem cell-conditioned medium (CM) has been reported to attenuate lung injury. Neural crest stem cells (NCSCs), a type of multipotent stem cells, are more easily obtained than mesenchymal stem cells. We hypothesize that NCSC-CM has anti-inflammatory properties that could protect against IR-induced lung injury in rats. In this study, NCSC-CM was derived from rat NCSCs. Typical acute lung injury was induced by 30-min ischemia followed by 90-min reperfusion in adult male Sprague–Dawley rats. Bronchoalveolar lavage fluid (BALF) and lung tissues were collected to analyze the degree of lung injury after the experiment. NCSC-CM was administered before ischemia and after reperfusion. NCSC-CM treatment significantly attenuated IR-induced lung edema, as indicated by decreases in pulmonary vascular permeability, lung weight gain, wet to dry weight ratio, lung weight to body weight ratio, pulmonary arterial pressure, and protein level in BALF. The levels of tumor necrosis factor-α and interleukin-6 in the BALF were also significantly decreased. Additionally, NCSC-CM improved lung pathology and neutrophil infiltration in the lung tissue, and significantly suppressed nuclear factor (NF)-κB activity and IκB-α degradation in the lung. However, heating NCSC-CM eliminated these protective effects. Our experiment demonstrates that NCSC-CM treatment decreases IR-induced acute lung injury and that the protective mechanism may be attributable to the inhibition of NF-κB activation and the inflammatory response. Therefore, NCSC-CM may be a novel approach for treating IR-induced lung injury.

Expression profile of microRNAs following bone marrow-derived mesenchymal stem cell treatment in lipopolysaccharide-induced acute lung injury

Immunomodulatory or immunosuppressive properties of bone marrow-derived mesenchymal stem cells (BM-MSCs) facilitate the treatment of acute respiratory distress syndrome and acute lung injury (ALI). Dysregulated miRNA (miRNA or miR) expression associated with the effects of BM-MSCs was assessed in a rat model of lipopolysaccharide (LPS)-induced ALI. The present study performed biochemical tests to assess five analytes, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate, blood urea nitrogen (BUN), and creatinine (CREA). Total cell count was assessed and the percentage of bronchoalveolar lavage neutrophil content was also examined. The results Histopathological examination of rat upper lobe lung tissue was then used to estimate lung injury score (LIS). The levels of AST, lactate, BUN and creatinine (excluding ALT), released into the circulation upon injury, were significantly lower in ALI rats treated with BM-MSCs than in ALI rats alone (P<0.05). BM-MSC rats exhibited a significantly decreased bronchoalveolar lavage neutrophil percentage and LIS compared with that of LPS treated rats alone (P<0.05). In addition, the miRNA expression profile was determined following treatment with BM-MSCs via microarray analysis. A total of 95/690 miRNAs were differentially expressed following the treatment of BM-MSCs in rats with ALI. Among the 95 miRNAs, 66 were upregulated and 29 were downregulated; 9 miRNAs were significantly upregulated (miR-1843-3p, miR-323-3p, miR-183-5p, miR-182 and miR-196b-3p) or downregulated (miR-547-3p, miR-301b-5p, miR-503-3p and miR-142-3p). A total of 3 miRNAs were inversely expressed in ALI treated with BM-MSCs compared with untreated ALI. Of these 3 miRNAs, the expression of miR-142-3p and miR-503-3p was upregulated in the LPS groups and downregulated in the BM-MSC groups. miR-196b-3p was downregulated in the LPS group and upregulated in the BM-MSC groups. miRNAs have a role in cell proliferation, immune response, inflammation and apoptosis, which may be associated with the therapeutic effects of BM-MSCs in ALI. In summary, BM-MSCs improved multi-organ damage and attenuated lung injury. Different miRNA profiles were expressed following BM-MSC treatment of ALI. These dysregulated miRNAs participated in BM-MSC-mediated immunomodulation of ALI.

Histopathologic heterogeneity of acute respiratory distress syndrome revealed by surgical lung biopsy and its clinical implications

BACKGROUND/AIMS

Diffuse alveolar damage (DAD) is the histopathologic hallmark of acute respiratory distress syndrome (ARDS). However, there are several non-DAD conditions mimicking ARDS. The purpose of this study was to investigate the histopathologic heterogeneity of ARDS revealed by surgical lung biopsy and its clinical relevance.

METHODS

We retrospectively analyzed 84 patients with ARDS who met the criteria of the Berlin definition and underwent surgical lung biopsy between January 2004 and December 2013 in three academic hospitals in Korea. We evaluated their histopathologic findings and compared the clinical outcomes. Additionally, the impact of surgical lung biopsy on therapeutic alterations was examined.

RESULTS

The histopathologic findings were highly heterogeneous. Of 84 patients undergoing surgical lung biopsy, DAD was observed in 31 patients (36.9%), while 53 patients (63.1%) did not have DAD. Among the non-DAD patients, diffuse interstitial lung diseases and infections were the most frequent histopathologic findings in 19 and 17 patients, respectively. Although the mortality rate was slightly higher in DAD (71.0%) than in non-DAD (62.3%), the difference was not significant. Overall, the biopsy results led to treatment alterations in 40 patients (47.6%). Patients with non-DAD were more likely to change the treatment than those with DAD (58.5% vs. 29.0%), but there were no significant improvements regarding the mortality rate.

CONCLUSIONS

The histopathologic findings of ARDS were highly heterogeneous and classic DAD was observed in one third of the patients who underwent surgical lung biopsy. Although therapeutic alterations were more common in patients with non-DAD-ARDS, there were no significant improvements in the mortality rate.

Xenogeneic human umbilical cord-derived mesenchymal stem cells reduce mortality in rats with acute respiratory distress syndrome complicated by sepsis

This study tested the hypothesis that xenogeneic human umbilical cord-derived mesenchymal stem cell (HUCDMSC) therapy would improve survival rates in rats with acute respiratory distress-syndrome (ARDS, induction by 48 h inhalation of 100% oxygen) and sepsis-syndrome (SS, induction by cecal-ligation and puncture) (ARDS-SS). Adult-male Sprague-Dawley rats were categorized into group 1 (sham-controls), group 2 (ARDS-SS), group 3 [ARDS-SS+HUCDMSC (1.2 ×106 cells administered 1 h after SS-induction)], and group 4 [ARDS-SS+HUCDMSC (1.2 ×106 cells administered 24 h after SS-induction)]. The mortality rate was higher in groups 2 and 4 than in groups 1 and 3 (all p<0.0001). The blood pressure after 28 h was lower in groups 2, 3 and 4 (p<0.0001) than in group 1. Albumin levels and percentages of inflammatory cells in broncho-alveolar lavage fluid, and the percentages of inflammatory and immune cells in circulation, were lowest in group 1, highest in group 2, and higher in group 3 than group 4 (all p<0.0001). The percentages of inflammatory cells in ascites and kidney parenchyma showed identical patterns, as did kidney injury scores (all p<0.0001). EarlyHUCDMSC therapy reduced rodent mortality after induced ARDS-SS.

Inflammation is related to preoperative hypoxemia in patients with acute Stanford type A aortic dissection

Background

Preoperative hypoxemia is a frequent complication of acute Stanford type A aortic dissection (ATAAD). The aim of the present study was to determine which factors were associated with hypoxemia.

Methods

A series of data were collected in a statistical analysis to evaluate preoperative hypoxemia in patients with ATAAD. After retrospectively analyzing data for 172 patients, we identified the risk factors for preoperative hypoxemia. Hypoxemia was defined by an arterial partial pressure of oxygen to fraction of inspired oxygen (PaO₂/FiO₂) ratio of 200 or lower. Subsequent to identifying the patient population, a prospective study was conducted using ulinastatin as a preoperative intervention. The ulinastatin group received ulinastatin at a total dose of 300,000 units prior to surgery. All the pertinent factors were investigated through univariate and multiple logistic regression analysis.

Results

The factors associated with preoperative hypoxemia in ATAAD comprised the following: body mass index (BMI) ≥25; white blood cell count (WBC) and neutrophil counts; levels of C-reactive protein (CRP), D-dimer, and interleukin-6 (IL-6); ATAAD involving the celiac trunk, renal artery, or mesenteric artery. Logistic regression analysis showed that CRP and IL-6 levels were independent predictive factors. We found that ulinastatin effectively could improve oxygenation, since compared to the control group the oxygenation in the ulinastatin group was significantly improved.

Conclusions

Systemic inflammatory reactions played a vital role in preoperative hypoxemia after the onset of ATAAD. The oxygenation of the patient could be improved significantly by inhibiting the inflammatory response prior to surgery.

Preactivated and Disaggregated Shape-Changed Platelets Protected Against Acute Respiratory Distress Syndrome Complicated by Sepsis Through Inflammation Suppression

BACKGROUND

This study tested the hypothesis that preactivated and disaggregated shape-changed platelet (PreD-SCP) therapy attenuates lung injury from acute respiratory distress syndrome (ARDS) induced by 100% oxygen inhalation and complicated by sepsis through peritoneal administration of 1.5 mg/kg lipopolysaccharide (LPS).

METHODS

Adult male Sprague-Dawley rats, weighing 325 to 350 g, were randomized into group 1 (normal controls [NC]), group 2 (NC + PreD-SCP [3.0 × 10, intravenous administration]), group 3 (ARDS-LPS), and group 4 (ARDS-LPS + PreD-SCP), and sacrificed by 72 h after ARDS induction.

RESULTS

The lung injury score was significantly higher in group 3 than that in other groups, and significantly higher in group 4 than that in groups 1 and 2, whereas the numbers of alveolar sacs and oxygen saturation (%) showed a reversed pattern compared with that of lung injury score among the four groups (all P < 0.0001) without significant difference between groups 1 and 2. The expressions of proinflammatory cells (CD11+, CD14+, CD68+) and proteins (tumor necrosis factor [TNF]-α, nuclear factor [NF]-κB, interleukin [IL]-1ββ, matrix metalloproteinase [MMP]-9, inducible nitric oxide synthase, intercellular adhesion molecule-1) exhibited a pattern identical to the lung injury score. Circulating levels of white blood cell, IL-6, TNF-α, myeloperoxidase and CCL5, and pulmonary protein expressions of oxidative stress (NOX-1/NOX-2, oxidized protein), apoptotic (Bax, cleaved caspase 3/poly (ADP-ribose) polymerase), fibrotic (Smad3, transforming growth factor [TGF]-β), and DNA damage (γ-H2AX) biomarkers showed an identical pattern, whereas protein expressions of antifibrotic (Smad1/5, bone morphogenetic protein [BMP]-2) and anti-inflammatory (Bcl-2) biomarkers demonstrated an opposite pattern compared with the proinflammatory indices among the four groups (all P < 0.001).

CONCLUSIONS

PreD-SCP therapy effectively improved lung injury in ARDS complicated by sepsis.

MicroRNAs as biomarkers of acute lung injury

Acute respiratory distress syndrome (ARDS) is a common and complex inflammatory lung diseases affecting critically ill patients requiring mechanical ventilation. MicroRNAs (miRNAs), a novel pathway of non-coding RNA molecules that regulate gene expression at the post-transcriptional level, have emerged as a novel class of gene expression, and can play important roles in inflammation or apoptosis, which are common manifestations of ARDS and diffuse alveolar damage (DAD). In the present review, we discuss the role of miRNAs as biomarkers of ARDS and DAD, and their potential use as therapeutic targets for this condition.

Effects of S-Nitroso-N-Acetyl-Penicillamine (SNAP) on Inflammation, Lung Tissue Apoptosis and iNOS Activity in a Rabbit Model of Acute Lung Injury

Acute lung injury is characterized by lung edema, surfactant dysfunction, and inflammation. The main goal of our study was to evaluate effects of S-nitroso-N-acetyl-penicillamine (SNAP) on migration of cells into the lung and their activation, inducible NO synthase (iNOS) activity, and apoptosis in experimental acute lung injury (ALI) in rabbits. ALI was induced by repetitive lung lavage with saline. The animals were divided into the following groups: (1) ALI without therapy, (2) lung injury treated with SNAP (ALI + SNAP), and (3) healthy animals (Control). After 5 h of ventilation, total and differential counts of cells in the bronchoalveolar lavage fluid (BALF) were assessed. Concentrations of interleukins (IL)-1ß, IL-6, and IL-8, endogenous secretory receptor for advanced glycation endproducts (esRAGE), sphingosine-1-phosphate receptor (S1PR)3, caspase-3, and mRNA expression of inducible NO synthase (iNOS) in lung tissue and nitrite/nitrate in plasma were analyzed. In the right lung, apoptotic cells were evaluated by TUNEL assay. In the animals with ALI, higher counts of cells, mainly neutrophils, in BALF and increased production of pro-inflammatory substances were observed compared with controls. SNAP therapy reduced a leak of cells into the lung and decreased concentrations of pro-inflammatory and apoptotic markers, reduced mRNA expression of iNOS, and decreased apoptotic index in the lung.

Molecular and Immune Biomarkers in Acute Respiratory Distress Syndrome: A Perspective From Members of the Pulmonary Pathology Society

Acute respiratory distress syndrome (ARDS) is a multifactorial syndrome with high morbidity and mortality rates, characterized by deficiency in gas exchange and lung mechanics that lead to hypoxemia, dyspnea, and respiratory failure. Histologically, ARDS is characterized by an acute, exudative phase, combining diffuse alveolar damage and noncardiogenic edema, followed by a later fibroproliferative phase. Despite an enhanced understanding of ARDS pathogenesis, the capacity to predict the development of ARDS and to risk-stratify patients with the disease remains limited. Biomarkers may help to identify patients at the greatest risk of developing ARDS, to evaluate response to therapy, to predict outcome, and to improve clinical trials. The ARDS pathogenesis is presented in this article, as well as concepts and information on biomarkers that are currently used clinically or are available for laboratory use by academic and practicing pathologists and the developing and validating of new assays, focusing on the assays' major biologic roles in lung injury and/or repair and to ultimately suggest innovative, therapeutic approaches.

Evaluation of LPS-Induced Acute Lung Injury Attenuation in Rats by Aminothiazole-Paeonol Derivatives

Paeonol is a key phenolic compound in the root bark of Moutan Cortex Radicis that has been used in traditional Chinese Medicine to ameliorate inflammation. A series of aminothiazole-paeonol derivatives (APDs) were synthesized in this work and subjected to preliminary evaluation in cells followed by verification in animals. Quantification of monocyte chemotactic protein-1 (MCP-1) and interleukin-6 (IL-6) in culture media of LPS-activated A549 cells, a lung epithelial adenocarcinoma cell line, were used to investigate the anti-inflammatory capability of APDs. ALI-bearing rats were employed to verify therapeutic efficacy of APDs according to observations of total cells, protein amounts, MCP-1 and IL-6 in bronchoalveolar lavage fluid (BALF). Histopathological examinations of lung tissues were consequently applied for validation of APDs. Among these compounds, 2-(2-aminothiazol-4-yl)-5-methoxyphenol (4) had the most potent activity, showing comparable inhibition of MCP-1/IL-6 and superior elimination of neutrophil infiltration and protein exudation in lungs compared to others as well as dexamethasone. This study demonstrated a comprehensive strategy to evaluate APDs through integration of cell-based screening and animal-based verification. In order to fulfill unmet needs of treating acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), APDs introduced in this work could be promising lead compounds to develop high potent anti-inflammation agents.

Experimental Models of Acute Lung Injury in the Newborns

Acute lung injury in the preterm newborns can originate from prematurity of the lung and insufficient synthesis of pulmonary surfactant. This situation is known as respiratory distress syndrome (RDS). In the term neonates, the respiratory insufficiency is related to a secondary inactivation of the pulmonary surfactant, for instance, by action of endotoxins in bacterial pneumonia or by effects of aspirated meconium. The use of experimental models of the mentioned situations provides new information on the pathophysiology of these disorders and offers unique possibility to test novel therapeutic approaches in the conditions which are very similar to the clinical syndromes. Herewith we review the advantages and limitations of the use of experimental models of RDS and meconium aspiration syndrome (MAS) and their value for clinics.

Effect of HA330 resin-directed hemoadsorption on a porcine acute respiratory distress syndrome model

Background

Blood purification is an emerging approach to dampening the cytokine storm. This study aims to assess the efficacy of HA330 resin-directed hemoadsorption (HA) on endotoxin-induced porcine acute respiratory distress syndrome (ARDS) model.

Methods

Twenty-four Chinese domestic pigs were allocated into saline group receiving intravenous infusion of saline (N = 6) and endotoxin group receiving intravenous infusion of LPS (N = 18). When ALI model was initially diagnosed, six pigs in the LPS and saline group were killed for BALF and histopathological analysis. The remaining 12 pigs in LPS group received 3-h HA (N = 6) or HA-sham (N = 6) treatment, respectively. Following another 5-h observation, animals were killed. Variables on hemodynamics, blood gases and lung mechanics were recorded at a series of time points. Differentially expressed cytokines and proteins were determined by ELISA and proteomics.

Results

HA treatment significantly improved injured oxygenation induced by LPS. HA also partially improved the barrier permeability and reduced lung edema and inflammation/injury induced by LPS infusion. Proteomic analysis showed the differentially expressed proteins between HA- and HA-sham-treated groups mostly belonged to the categories of acute inflammation/immune response, and proteolysis.

Conclusions

Hemoadsorption improved ARDS possibly by blunting the cytokine storm and by restoring homeostasis of the disordered proteome milieu in the exudative phase.

Electronic supplementary material

The online version of this article (doi:10.1186/s13613-017-0287-0) contains supplementary material, which is available to authorized users.

JAK2/STAT3 Pathway Was Associated with the Protective Effects of IL-22 On Aortic Dissection with Acute Lung Injury

Patients with aortic dissection (AD) may present acute lung injury (ALI) that may affect the prognosis. In this study, we aim to investigate the roles and mechanism of IL-22 in the pathogenesis of AD complicated with ALI. Six hundred and twenty-one AD patients were included, and the incidence of ALI and pulmonary CT findings were analyzed. Mouse ALI model was established through AngII, and then IL-22 injection and AG490 were given. The pathological changes, infiltration of inflammatory cells, and expression of STAT3 were determined. For the in vitro experiment, cultivated pulmonary microvascular endothelial cells (PMVECs) were treated by angiotensin II (AngII), followed by treating with IL-22 and/or AG490. The expression and migration of STAT3 was determined. Flow cytometry was carried out to evaluate the apoptosis. IL-22 contributed to the expression of STAT3 in lung tissues and attenuation of ALI. IL-22 obviously inhibited the apoptosis of PMVECs mediated by AngII and downregulated the expression and intranuclear transmission of STAT3. Such phenomenon was completely inhibited upon administration of AG490, an inhibitor of JAK2. Our data showed IL-22 contributed to the inhibition of PMVEC apoptosis mediated by AngII through activating the JAK2/STAT3 signaling pathway, which may attenuate the ALI induced by AngII.

Effective protection against acute respiratory distress syndrome/sepsis injury by combined adipose-derived mesenchymal stem cells and preactivated disaggregated platelets

This study assessed whether combining adipose-derived mesenchymal stem cells (ADMSC) with preactivated, disaggregated shape-changed platelets (PreD-SCP) was superior to either therapy alone for protecting rat lung from acute respiratory distress syndrome (ARDS) complicated by sepsis. ARDS and sepsis were induced through 100% oxygen inhalation and peritoneal administration of 1.5 mg/kg lipopolysaccharide (LPS), respectively. Adult-male Sprague-Dawley rats (n=40) were randomized into sham-control (SC), ARDS-LPS, ARDS-LPS-ADMSC (1.2x10⁶ cells), ARDS-LPS-PreD-SCP (3.0x10⁸, intravenous administration), and ARDS-LPS-ADMS/PreD-SCP groups, and were sacrificed 72 h after 48 h ARDS induction. Lung injury scores (LIS) and collagen deposition were highest in ARDS-LPS, lowest in SC, higher in ARDS-LPS+ADMSC than in ARDS-LPS+PreD-SCP and ARDS-LPS+ADMS/PreD-SCP, and higher in ARDS-LPS+PreD-SCP than in ARDS-LPS+ADMS/PreD-SCP (all p<0.0001). Alveolar-sac numbers, oxygen saturation, endothelial marker levels, and mitochondrial cytochrome-C levels exhibited opposite patterns with respect to LIS (all p<0.001). Levels of inflammatory, oxidative-stress, apoptosis, mitochondrial/DNA damage, and MAPK and Akt signaling markers exhibited patterns identical to that of LIS (all p<0.001). Anti-oxidant and anti-inflammatory protein levels increased progressively from SC to ARDS-LPS+ADMS/PreD-SCP (all p<0.0001). These findings indicate combined ADMSC/PreD-SCP was superior to either therapy alone for protecting rat lung from ARDS-sepsis injury.

Oridonin attenuates the release of pro-inflammatory cytokines in lipopolysaccharide-induced RAW264.7 cells and acute lung injury

Acute lung injury (ALI) is a life-threatening inflammatory disease owing to the lack of specific and effective therapies. Oridonin (Ori) is an active diterpenoid isolated from Rabdosiarubescens (R.rubescens) that has been shown to possess a broadspectrum pharmacological properties including anti-inflammatory, antitumour, antioxidative and neuroregulatory effects. However, its potential protective mechanism in ALI is not well characterized. In this study, we demonstrated that Ori reduces the mortality of mice with ALI induced by a high dose of lipopolysaccharide (LPS), which suggests that Ori has a protective effect on LPS induced ALI. Next, our results confirmed that Ori improves LPS-induced localized pulmonary pathology and decreased the concentration of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) in the serum. Nuclear factor-kappa B (NF-κB) is capable of regulating the transcription of pro-inflammatory factors. Interestingly, our results showed that Ori inhibits the expression of TLR4/MyD88 and phosphorylation of NF-κB p65 in lung tissues. To confirm this, we further validated the possible regulatory anti-inflammatory mechanisms of Ori in vitro. LPS-induced RAW264.7 cells, which are widely used as an inflammation model to evaluate the potential protective effect of drugs in vitro, were chosen for this study. Similar results were observed, that is, pre-treatment with Ori, markedly inhibited the nuclear translocation and phosphorylation of NF-κB p65 induced by LPS and subsequently decreased the release of pro-inflammatory cytokines that were increased by LPS. Overall, these results demonstrated that Ori exerts a therapeutic effect on ALI by inhibiting the release of pro-inflammatory cytokines, such as IL-1β, IL-6, and TNF-α, through the TLR4/MyD88/NF-κB axis.

Intravenous dexamethasone attenuated inflammation and influenced apoptosis of lung cells in an experimental model of acute lung injury

Acute lung injury (ALI) is characterized by diffuse alveolar damage, inflammation, and transmigration and activation of inflammatory cells. This study evaluated if intravenous dexamethasone can influence lung inflammation and apoptosis in lavage-induced ALI. ALI was induced in rabbits by repetitive saline lung lavage (30 ml/kg, 9+/-3-times). Animals were divided into 3 groups: ALI without therapy (ALI), ALI treated with dexamethasone i.v. (0.5 mg/kg, Dexamed; ALI+DEX), and healthy non-ventilated controls (Control). After following 5 h of ventilation, ALI animals were overdosed by anesthetics. Total and differential counts of cells in bronchoalveolar lavage fluid (BAL) were estimated. Lung edema was expressed as wet/dry weight ratio. Concentrations of IL-1beta, IL-8, esRAGE, S1PR3 in the lung were analyzed by ELISA methods. In right lung, apoptotic cells were evaluated by TUNEL assay and caspase-3 immunohistochemically. Dexamethasone showed a trend to improve lung functions and histopathological changes, reduced leak of neutrophils (P<0.001) into the lung, decreased concentrations of pro-inflammatory IL-1beta (P<0.05) and marker of lung injury esRAGE (P<0.05), lung edema formation (P<0.05), and lung apoptotic index (P<0.01), but increased immunoreactivity of caspase-3 in the lung (P<0.001). Considering the action of dexamethasone on respiratory parameters and lung injury, the results indicate potential of this therapy in ALI.

Senegenin Ameliorate Acute Lung Injury Through Reduction of Oxidative Stress and Inhibition of Inflammation in Cecal Ligation and Puncture-Induced Sepsis Rats

The purpose of this study was to assess the protective effect of senegenin on acute lung injury (ALI) in rats induced by sepsis. Rat ALI model was reproduced by cecal ligation and puncture (CLP). All rats were randomly divided into five groups: group 1 (control), group 2 (CLP), group 3 (CLP + senegenin 15 mg/kg), group 4 (CLP + senegenin 30 mg/kg), and group 5 (CLP + senegenin 60 mg/kg). CLP + senegenin groups received senegenin by gavage daily for consecutive 5 days, respectively, while the mice in control and CLP groups were given an equivalent volume of saline. We detected the lung wet/dry weight ratios and the histopathology of the lung. The levels of lung tissue myeloperoxidase (MPO), malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH) were determined. Meanwhile, the nuclear factor-kappa B (NF-κB) activation, tumor necrosis factor-alpha (TNF-α), and interleukin-1β (IL-1β) levels were studied. The results demonstrated that senegenin treatment significantly attenuated CLP-induced lung injury, including reduction of lung wet/dry weight ratio, protein leak, infiltration of leukocytes, and MPO activity. In addition, senegenin markedly decreased MDA content and increased SOD activity and GSH level. Serum levels of TNF-α and IL-1β were also decreased by senegenin administration. Furthermore, senegenin administration inhibited the nuclear translocation of NF-κB in the lungs. These findings indicate that senegenin exerts protective effects on CLP-induced septic rats. Senegenin may be a potential therapeutic agent against sepsis.

Desflurane inhalation before ischemia increases ischemia-reperfusion-induced vascular leakage in isolated rabbit lungs

BACKGROUND

Isoflurane and sevoflurane protect lungs with ischemia-reperfusion (IR) injury. We examined the influence of desflurane on IR lung injury using isolated rabbit lungs perfused with a physiological salt solution.

METHODS

The isolated lungs were divided into three groups: IR, desflurane-treated ischemia-reperfusion (DES-IR), and ventilation/perfusion-continued control (Cont) groups (n = 6 per group). In the DES-IR group, inhalation of desflurane at 1 minimum alveolar concentration (MAC) was conducted in a stable 30-min phase. In the IR and DES-IR groups, ventilation/perfusion was stopped for 75 min after the stable phase. Subsequently, they were resumed. Each lung was placed on a balance, and weighed. Weight changes were measured serially throughout this experiment. The coefficient of filtration (K_fc) was determined immediately before ischemia and 60 min after reperfusion. Furthermore, bronchoalveolar lavage fluid (BALF) was collected from the right bronchus at the completion of the experiment. After the completion of the experiment, the left lung was dried, and the lung wet-to-dry weight ratio (W/D) was calculated.

RESULTS

The K_fc values at 60 min after perfusion were 0.40 ± 0.13 ml/min/mmHg/100 g in the DES-IR group, 0.26 ± 0.07 ml/min/mmHg/100 g in the IR group, and 0.22 ± 0.08 (mean ± SD) ml/mmHg/100 g in the Cont group. In the DES-IR group, the K_fc at 60 min after the start of reperfusion was significantly higher than in the other groups. In the DES-IR group, W/D was significantly higher than in the Cont group. In the DES-IR group, the BALF concentrations of nitric oxide metabolites were significantly higher than in the other groups. In the DES-IR group, the total amount of vascular endothelial growth factor in BALF was significantly higher than in the Cont group.

CONCLUSIONS

The pre-inhalation of desflurane at 1 MAC exacerbates pulmonary IR injury in isolated/perfused rabbit lungs.

Inhaled sulfur dioxide causes pulmonary and systemic inflammation leading to fibrotic respiratory disease in a rat model of chemical-induced lung injury

Inhalation of high concentrations of sulfur dioxide (SO₂) affects the lungs and can be immediately dangerous to life. We examined the development of acute and long-term effects after exposure of SO₂ in Sprague-Dawley rats, in particular inflammatory responses, airway hyperresponsiveness (AHR) and lung fibrosis. Animals were subjected to a single exposure of 2200ppm SO₂ during 10min and treated with a single dose of the anti-inflammatory corticosteroid dexamethasone 1h following exposure. Exposed rats showed labored breathing, decreased body-weight and an acute inflammation with neutrophil and macrophage airway infiltrates 5h post exposure. The acute effects were characterized by bronchial damage restricted to the larger bronchi with widespread injured mucosal epithelial lining. Rats displayed hyperreactive airways 24h after exposure as indicated by increased methacholine-induced respiratory resistance. The inflammatory infiltrates remained in lung tissue for at least 14 days but at the late time-point the dominating granulocyte types had changed from neutrophils to eosinophils. Analysis of immunoregulatory and pro-inflammatory cytokines in serum and airways implicated mixed macrophage phenotypes (M1/M2) and T helper cell activation of both T_H1 and T_H2 subtypes. Increased expression of the pro-fibrotic cytokine TGFβ1 was detected in airways 24h post exposure and remained increased at the late time-points (14 and 28 days). The histopathology analysis confirmed a significant collagen deposition 14 days post exposure. Treatment with dexamethasone significantly counteracted the acute inflammatory response but was insufficient for complete protection against SO₂-induced adverse effects, i.e. treatment only provided partial protection against AHR and the long-term fibrosis.

Receptor Interacting Protein 3-Mediated Necroptosis Promotes Lipopolysaccharide-Induced Inflammation and Acute Respiratory Distress Syndrome in Mice

Necrosis amplifies inflammation and plays important roles in acute respiratory distress syndrome (ARDS). Necroptosis is a newly identified programmed necrosis that is mediated by receptor interacting protein 3 (RIP3). However, the potential involvement and impact of necroptosis in lipopolysaccharide (LPS)-induced ARDS remains unknown. We therefore explored the role and mechanism of RIP3-mediated necroptosis in LPS-induced ARDS. Mice were instilled with increasing doses of LPS intratracheally to induce different degrees of ARDS. Lung tissues were harvested for histological and TUNEL staining and western blot for RIP3, p-RIP3, X-linked inhibitor of apoptosis protein (XIAP), mixed lineage kinase domain-like protein (MLKL), total and cleaved caspases-3/8. Then, wild-type and RIP3 knock-out mice were induced ARDS with 30 mg/kg LPS. Pulmonary cellular necrosis was labeled by the propidium Iodide (PI) staining. Levels of TNF-a, Interleukin (IL)-1β, IL-6, IL-1α, IL-10 and HMGB1, tissue myeloperoxidase (MPO) activity, neutrophil counts and total protein concentration were measured. Results showed that in high dose LPS (30mg/kg and 40mg/kg) -induced severe ARDS, RIP3 protein was increased significantly, accompanied by increases of p-RIP3 and MLKL, while in low dose LPS (10mg/kg and 20mg/kg) -induced mild ARDS, apoptosis was remarkably increased. In LPS-induced severe ARDS, RIP3 knock-out alleviated the hypothermia symptom, increased survival rate and ameliorated the lung tissue injury RIP3 depletion also attenuated LPS-induced increase in IL-1α/β, IL-6 and HMGB1 release, decreased tissue MPO activity, and reduced neutrophil influx and total protein concentration in BALF in severe ARDS. Further, RIP3 depletion reduced the necrotic cells in the lung and decreased the expression of MLKL, but had no impact on cleaved caspase-3 in LPS-induced ARDS. It is concluded that RIP3-mediated necroptosis is a major mechanism of enhanced inflammation and lung tissue injury in high dose LPS- induced severe ARDS in mice.

[Respiratory monitoring of pediatric patients in the Intensive Care Unit]

Respiratory monitoring plays an important role in the care of children with acute respiratory failure. Therefore, its proper use and correct interpretation (recognizing which signals and variables should be prioritized) should help to a better understanding of the pathophysiology of the disease and the effects of therapeutic interventions. In addition, ventilated patient monitoring, among other determinations, allows to evaluate various parameters of respiratory mechanics, know the status of the different components of the respiratory system and guide the adjustments of ventilatory therapy. In this update, the usefulness of several techniques of respiratory monitoring including conventional respiratory monitoring and more recent methods are described. Moreover, basic concepts of mechanical ventilation, their interpretation and how the appropriate analysis of the information obtained can cause an impact on the clinical management of the patient are defined.

Protective effects of thoracic epidural anesthesia on hypoxia-induced acute lung injury in rabbits

The mechanism underlying the effect of thoracic epidural anesthesia (TEA) on hypoxia-induced acute lung injury (ALI) is currently unknown. In the present study, a rabbit acute lung injury model was established to investigate the effects of TEA on inflammatory factors, pulmonary surfactant and ultrastructure. A total of 56 rabbits were randomly assigned to four groups (n=14 per group): Control group (Group C), hypoxia group (Group H), sevoflurane group (Group S) and combined sevoflurane-epidural anesthesia group (Group ES). The ALI model was considered to have been successfully induced when the ratio of arterial oxygen partial pressure to fractional inspired oxygen was <300. The correct placement of a catheter for TEA was confirmed using epidurography. ALI was maintained for 3 h. Arterial blood samples were collected from all groups during spontaneous breathing (T₀) and at 3 h after ALI induction (T₅) in order to evaluate the serum levels of interleukin (IL)-6, IL-8 and IL-10. Bronchoalveolar lavage fluid was harvested to determine the total phospholipid, saturated phosphatidylcholine and total protein levels. Furthermore, the dry/wet weight ratio and the mRNA expression levels of IL-6, IL-8 and IL-10 in the lung tissue were determined using ELISA. In addition, light and transmission electron microscopy and histological techniques were used to examine the morphology of alveolar type II cells in the rat lung tissue. The results indicate that changes of serum IL-6, IL-8 and IL-10 levels following ALI were consistent with the changes in the mRNA expression levels of IL-6, IL-8 and IL-10 in the lung tissue. TEA attenuated these changes and thus reduced the severity of the ALI. In addition, TEA improved the alveolar structure, reduced the number of polymorphonuclear cells and mitigated the damage of lamellar bodies. In summary, the results of the present study indicate that TEA reduces lung tissue damage by inhibiting systemic and local inflammation, decreasing the inactivation of pulmonary surfactant and improving the alveolar ultrastructure following ALI.

Significance of Serum mtDNA Concentration in Lung Injury Induced by Hip Fracture

Acute lung injury is the most serious and fatal complication of the elderly patients with hip fracture, but the mechanisms are unknown. Recent studies demonstrated the mitochondrial DNA (mtDNA) release was associated with lung injury after trauma. This study aimed to examine the differential release of mtDNA between younger and elderly rats suffering from hip fracture and to investigate the possible mechanism of mtDNA in the lung injury induced by hip fracture. In the first part of the study, we investigated the effects of hip fracture on the rats. The elderly and younger rats, respectively, received hip fracture operations. The degree of lung injury was evaluated, toll-like receptor 9 (TLR9) and nuclear factor kappa B (NF-κB) were determined using Western blot, and mtDNA were analyzed by fluorescent quantitative polymerase chain reaction. In the second part of the study, we investigated the effects of mtDNA on the rats. The elderly and younger rats directly received intravenous injections with mtDNA. After 24 h, the specimens were collected and detected as the first part. Hip fracture resulted in significant mtDNA release, TLR9 and NF-κB p65 expression, and lung injury in the rats. Meanwhile, the mtDNA injection could indirectly induce lung injury. Compared to the younger ones, the elderly rats suffered more serious lung injury after hip fracture and mtDNA injection. These results suggest that the lung injury induced by hip fracture may be involved with the mtDNA release and its TLR9/NF-κB pathway.

MicroRNAs: Novel regulatory molecules in acute lung injury/acute respiratory distress syndrome

Acute lung injury (ALI) and the more severe acute respiratory distress syndrome (ARDS) are common and complex inflammatory lung diseases. MicroRNAs (miRNAs), a type of non-coding RNA molecule that regulate gene expression at the post-transcriptional level, have emerged as a novel class of gene regulators, which have critical roles in a wide range of human disorders and diseases, including ALI. Certain types of miRNAs are abnormally expressed in response to lung injury. miRNAs can regulate inflammation pathways by targeting specific molecules and modulate immune response in the process of lung injury and repair. The regulation of miRNA can relieve injury response and promote the recovery of ALI/ARDS. Therefore, miRNAs may serve as novel therapeutic targets in ALI/ARDS.

Soluble Vascular Cell Adhesion Molecule-1 (sVCAM-1) Is Elevated in Bronchoalveolar Lavage Fluid of Patients with Acute Respiratory Distress Syndrome

INTRODUCTION

Pulmonary vascular endothelial activation has been implicated in acute respiratory distress syndrome (ARDS), yet little is known about the presence and role of endothelial activation markers in the alveolar space in ARDS. We hypothesized that endothelial activation biomarkers would be differentially expressed in bronchoalveolar lavage fluid from patients with ARDS compared with healthy volunteers, and that biomarker concentrations would be associated with ARDS severity.

METHODS

We performed a cross-sectional analysis of data from 26 intubated patients with ARDS undergoing evaluation for clinically suspected ventilator-associated pneumonia and five healthy volunteers. Patients underwent bronchoalveolar lavage a median of five days after intubation. Healthy volunteers also underwent bronchoalveolar lavage. Endothelial activation biomarkers (soluble vascular cell adhesion molecule-1 [sVCAM-1], soluble endothelial selectin [sESEL], angiopoietin-1 [Ang-1] and angiopoietin-2 [Ang-2]) were measured in bronchoalveolar lavage fluid. Clinically suspected ventilator-associated pneumonia was confirmed with microbiologic culture data.

RESULTS

Patients with ARDS had significantly higher median sVCAM-1 concentrations in the bronchoalveolar lavage fluid compared with healthy volunteers (985 vs 119 pg/mL, p = 0.03). Additionally, there was a trend toward greater bronchoalveolar lavage fluid sVCAM-1 concentrations among patients with moderate/severe compared to mild ARDS (1395 vs 209 pg/mL, p = 0.06). We did not detect significant differences in bronchoalveolar lavage fluid levels of sESEL, Ang-1 or Ang-2 between patients with ARDS and healthy volunteers. Median bronchoalveolar lavage fluid biomarker levels did not differ between patients with and without microbiologically-confirmed ventilator-associated pneumonia.

CONCLUSIONS

sVCAM-1 concentrations were significantly higher in the bronchoalveolar lavage fluid of patients with ARDS compared to healthy controls, and tended to be higher in moderate/severe ARDS compared to mild ARDS. Our findings add to the growing evidence supporting the concept that endothelial activation plays an important mechanistic role in the pathogenesis of ARDS. Further studies are necessary to characterize the role and/or clinical significance of sVCAM-1 and other endothelial activation markers present in the alveolar space in ARDS.

A Pathophysiologic Approach to Biomarkers in Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is an acute-onset hypoxic condition with radiographic bilateral lung infiltration. It is characterized by an acute exudative phase combining diffuse alveolar damage and lung edema followed by a later fibroproliferative phase. Despite an improved understanding of ARDS pathobiology, our ability to predict the development of ARDS and risk-stratify patients with the disease remains limited. Biomarkers may help to identify patients at the highest risk of developing ARDS, assess response to therapy, predict outcome, and optimize enrollment in clinical trials. After a short description of ARDS pathobiology, here, we review the scientific evidence that supports the value of various ARDS biomarkers with regard to their major biological roles in ARDS-associated lung injury and/or repair. Ongoing research aims at identifying and characterizing novel biomarkers, in order to highlight relevant mechanistic explorations of lung injury and repair, and to ultimately develop innovative therapeutic approaches for ARDS patients. This review will focus on the pathophysiologic, diagnostic, and therapeutic implications of biomarkers in ARDS and on their utility to ultimately improve patient care.

Impact of mechanical ventilation on the pathophysiology of progressive acute lung injury

The earliest description of what is now known as the acute respiratory distress syndrome (ARDS) was a highly lethal double pneumonia. Ashbaugh and colleagues (Ashbaugh DG, Bigelow DB, Petty TL, Levine BE Lancet 2: 319-323, 1967) correctly identified the disease as ARDS in 1967. Their initial study showing the positive effect of mechanical ventilation with positive end-expiratory pressure (PEEP) on ARDS mortality was dampened when it was discovered that improperly used mechanical ventilation can cause a secondary ventilator-induced lung injury (VILI), thereby greatly exacerbating ARDS mortality. This Synthesis Report will review the pathophysiology of ARDS and VILI from a mechanical stress-strain perspective. Although inflammation is also an important component of VILI pathology, it is secondary to the mechanical damage caused by excessive strain. The mechanical breath will be deconstructed to show that multiple parameters that comprise the breath-airway pressure, flows, volumes, and the duration during which they are applied to each breath-are critical to lung injury and protection. Specifically, the mechanisms by which a properly set mechanical breath can reduce the development of excessive fluid flux and pulmonary edema, which are a hallmark of ARDS pathology, are reviewed. Using our knowledge of how multiple parameters in the mechanical breath affect lung physiology, the optimal combination of pressures, volumes, flows, and durations that should offer maximum lung protection are postulated.

Riboflavin attenuates lipopolysaccharide-induced lung injury in rats

Riboflavin (vitamin B2) is an easily absorbed micronutrient with a key role in maintaining health in humans and animals. It is the central component of the cofactors flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) and is therefore required by all flavoproteins. Riboflavin also works as an antioxidant by scavenging free radicals. The present study was designed to evaluate the effects of riboflavin against acute lungs injury induced by the administration of a single intranasal dose (20 μg/rat) of lipopolysaccharides (LPS) in experimental rats. Administration of LPS resulted in marked increase in malondialdehyde (MDA) level (p < 0.01) and MPO activity (p < 0.001), whereas marked decrease in glutathione (GSH) content (p < 0.001), glutathione reductase (GR) (p < 0.001) and glutathione peroxidase (p < 0.01) activity. These changes were significantly (p < 0.001) improved by treatment with riboflavin in a dose-dependent manner (30 and 100 mg/kg, respectively). Riboflavin (100 mg/kg, p.o.) showed similar protective effects as dexamethasone (1 mg/kg, p.o.). Administration of LPS showed marked cellular changes including interstitial edema, hemorrhage, infiltration of PMNs, etc., which were reversed by riboflavin administration. Histopathological examinations showed normal morphological structures of lungs tissue in the control group. These biochemical and histopathological examination were appended with iNOS and CAT gene expression. The iNOS mRNA expression was increased significantly (p < 0.001) and levels of CAT mRNA expression was decreased significantly (p < 0.001) in the animals exposed to LPS, while treatment with riboflavin significantly (p < 0.01) improved expression of both gene. In conclusion, the present study clearly demonstrated that riboflavin caused a protective effect against LPS-induced ALI. These results suggest that riboflavin may be used to protect against toxic effect of LPS in lungs.

Platelet-derived Wnt antagonist Dickkopf-1 is implicated in ICAM-1/VCAM-1-mediated neutrophilic acute lung inflammation

Neutrophil infiltration represents the early acute inflammatory response in acute lung injury. The recruitment of neutrophils from the peripheral blood across the endothelial-epithelial barrier into the alveolar airspace is highly regulated by the adhesion molecules on alveolar epithelial cells (AECs). Wnt/β-catenin signaling is involved in the progression of inflammatory lung diseases including asthma, emphysema, and pulmonary fibrosis. However, the function of Wnt/β-catenin signaling in acute lung inflammation is unknown. Here, we identified platelet-derived Dickkopf-1 (Dkk1) as the major Wnt antagonist contributing to the suppression of Wnt/β-catenin signaling in AECs during acute lung inflammation. Intratracheal administration of Wnt3a or an antibody capable of neutralizing Dkk1 inhibited neutrophil influx into the alveolar airspace of injured lungs. Activation of Wnt/β-catenin signaling in AECs attenuated intercellular adhesion molecule 1 (ICAM-1)/vascular cell adhesion molecule 1 (VCAM-1)-mediated adhesion of both macrophages and neutrophils to AECs. Our results suggest a role for Wnt/β-catenin signaling in modulating the inflammatory response, and a functional communication between platelets and AECs during acute lung inflammation. Targeting Wnt/β-catenin signaling and the communication between platelets and AECs therefore represents potential therapeutic strategies to limit the damage of acute pulmonary inflammation.

The Immediate Intramedullary Nailing Surgery Increased the Mitochondrial DNA Release That Aggravated Systemic Inflammatory Response and Lung Injury Induced by Elderly Hip Fracture

Conventional concept suggests that immediate surgery is the optimal choice for elderly hip fracture patients; however, few studies focus on the adverse effect of immediate surgery. This study aims to examine the adverse effect of immediate surgery, as well as to explore the meaning of mtDNA release after trauma. In the experiment, elderly rats, respectively, received hip fracture operations or hip fracture plus intramedullary nail surgery. After fracture operations, the serum mtDNA levels as well as the related indicators of systemic inflammatory response and lung injury significantly increased in the rats. After immediate surgery, the above variables were further increased. The serum mtDNA levels were significantly related with the serum cytokine (TNF-α and IL-10) levels and pulmonary histological score. In order to identify the meaning of mtDNA release following hip fracture, the elderly rats received injections with mtDNA. After treatment, the related indicators of systemic inflammatory response and lung injury significantly increased in the rats. These results demonstrated that the immediate surgery increased the mtDNA release that could aggravate systemic inflammatory response and lung injury induced by elderly hip fracture; serum mtDNA might serve as a potential biomarker of systemic inflammatory response and lung injury following elderly hip fracture.

Lipopolysaccharide challenge induces long pentraxin 3 expression in mice independently from acute lung injury

OBJECTIVE

To determine whether the onset of acute lung injury (ALI) induces the up-regulation of pentraxin 3 (PTX3) expression in mice and whether PTX3 concentration in the biofluid can help recognizing sepsis-induced ALI.

METHODS

Wild-type C57BL/6 mice (12-14 weeks old) were randomly divided into 3 groups. Mice in the group 1 (n=12) and group 2 (n=12) were instilled with lipopolysaccharide via intratracheal or intraperitoneal routes, respectively. Mice in the group 3 (n=8) were taken as blank controls. Pulmonary morphological and functional alterations were measured to determine the presence of experimental ALI. PTX3 expression in the lung was quantified at both protein and mRNA levels. PTX3 protein concentration in blood and bronchoalveolar lavage fluid was measured to evaluate its ability to diagnose sepsis-induced ALI by computing area under receiver operator characteristic curve (AUROCC).

RESULTS

ALI was commonly confirmed in the group 1 but never in the other groups. PTX3 expression was up-regulated indiscriminately among lipopolysaccharide-challenged mice. PTX3 protein concentration in the biofluid was unable to diagnose sepsis-induced ALI evidenced by its small AUROCC. PTX3 concentration in bronchoalveolar lavage fluid did not correlate with that in serum.

CONCLUSIONS

Lipopolysaccharide challenges induced PTX3 expression in mice regardless of the presence of ALI. PTX3 may act as an indicator of inflammatory response instead of organ injury per se.

Pathologic mechanical stress and endotoxin exposure increases lung endothelial microparticle shedding

Acute lung injury (ALI) results from infectious challenges and from pathologic lung distention produced by excessive tidal volume delivered during mechanical ventilation (ventilator-induced lung injury [VILI]) and is characterized by extensive alveolar and vascular dysfunction. Identification of novel ALI therapies is hampered by the lack of effective ALI/VILI biomarkers. We explored endothelial cell (EC)-derived microparticles (EMPs) (0.1-1 μm) as potentially important markers and potential mediators of lung vascular injury in preclinical models of ALI and VILI. We characterized EMPs (annexin V and CD31 immunoreactivity) produced from human lung ECs exposed to physiologic or pathologic mechanical stress (5 or 18% cyclic stretch [CS]) or to endotoxin (LPS). EC exposure to 18% CS or to LPS resulted in increased EMP shedding compared with static cells (∼ 4-fold and ∼ 2.5-fold increases, respectively). Proteomic analysis revealed unique 18% CS-derived (n = 10) and LPS-derived EMP proteins (n = 43). VILI-challenged mice (40 ml/kg, 4 h) exhibited increased plasma and bronchoalveolar lavage CD62E (E-selectin)-positive MPs compared with control mice. Finally, mice receiving intratracheal instillation of 18% CS-derived EMPs displayed significant lung inflammation and injury. These findings indicate that ALI/VILI-producing stimuli induce significant shedding of distinct EMP populations that may serve as potential ALI biomarkers and contribute to the severity of lung injury.

Systemic combined melatonin-mitochondria treatment improves acute respiratory distress syndrome in the rat

Despite high in-hospital mortality associated with acute respiratory distress syndrome (ARDS), there is no effective therapeutic strategy. We tested the hypothesis that combined melatonin-mitochondria treatment ameliorates 100% oxygen-induced ARDS in rats. Adult male Sprague-Dawley rats (n = 40) were equally categorized into normal controls, ARDS, ARDS-melatonin, ARDS with intravenous liver-derived mitochondria (1500 μg per rat 6 hr after ARDS induction), and ARDS receiving combined melatonin-mitochondria. The results showed that 22 hr after ARDS induction, oxygen saturation (saO2 ) was lowest in the ARDS group and highest in normal controls, significantly lower in ARDS-melatonin and ARDS-mitochondria than in combined melatonin-mitochondria group, and significantly lower in ARDS-mitochondria than in ARDS-melatonin group. Conversely, right ventricular systolic blood pressure and lung weight showed an opposite pattern compared with saO2 among all groups (all P < 0.001). Histological integrity of alveolar sacs showed a pattern identical to saO2 , whereas lung crowding score exhibited an opposite pattern (all P < 0.001). Albumin level and inflammatory cells (MPO+, CD40+, CD11b/c+) from bronchoalveolar lavage fluid showed a pattern opposite to saO2 (all P < 0.001). Protein expression of indices of inflammation (MMP-9, TNF-α, NF-κB), oxidative stress (oxidized protein, NO-1, NOX-2, NOX-4), apoptosis (mitochondrial Bax, cleaved caspase-3, and PARP), fibrosis (Smad3, TGF-β), mitochondrial damage (cytochrome C), and DNA damage (γ-H2AX+) exhibited an opposite pattern compared to saO2 in all groups, whereas protein (HO-1, NQO-1, GR, GPx) and cellular (HO-1+) expressions of antioxidants exhibited a progressively increased pattern from normal controls to ARDS combined melatonin-mitochondria group (all P < 0.001). In conclusion, combined melatonin-mitochondrial was superior to either treatment alone in attenuating ARDS in this rat model.

Breathprints of model murine bacterial lung infections are linked with immune response

In this model study, we explored the host's contribution of breath volatiles to diagnostic secondary electrospray ionisation-mass spectrometry (SESI-MS) breathprints for acute bacterial lung infections, their correlation with the host's immune response, and their use in identifying the lung pathogen. Murine airways were exposed to Pseudomonas aeruginosa and Staphylococcus aureus bacterial cell lysates or to PBS (controls), and their breath and bronchoalveolar lavage fluid (BALF) were collected at six time points (from 6 to 120 h) after exposure. Five to six mice per treatment group and four to six mice per control group were sampled at each time. Breath volatiles were analysed using SESI-MS and the BALF total leukocytes, polymorphonuclear neutrophils, lactate dehydrogenase activity, and cytokine concentrations were quantified. Lysate exposure breathprints contain host volatiles that persist for up to 120 h; are pathogen specific; are unique from breathprints of controls, active infections and cleared infections; and are correlated with the host's immune response. Bacterial lung infections induce changes to the host's breath volatiles that are selective and specific predictors of the source of infection. Harnessing the pathogen-specific volatiles in the host's breath may provide useful information for detecting latent bacterial lung infections and managing the spread of respiratory diseases.

Plasma biomarkers for acute respiratory distress syndrome: a systematic review and meta-analysis*

OBJECTIVE

Numerous studies have focused on biomarkers for acute lung injury and acute respiratory distress syndrome. Although several biomarkers have been identified, their relative performance is unclear. We aim to provide a quantitative overview of plasma-derived biomarkers associated with acute respiratory distress syndrome diagnosis or mortality.

DATA SOURCES

MEDLINE (inception to January 2012) and personal databases.

STUDY SELECTION

English-language studies on plasma biomarkers associated with acute respiratory distress syndrome diagnosis or mortality.

DATA EXTRACTION

Demographic variables, plasma levels of biomarker, statistical data, acute respiratory distress syndrome occurrence, and mortality rates were retrieved. The methodological quality was assessed with the Quality Assessment of Diagnostic Accuracy Studies score. Clinical outcomes included 1) diagnosis of acute respiratory distress syndrome in the at-risk population and 2) mortality in acute respiratory distress syndrome patients. For each biomarker, pooled odds ratios for clinical outcome were calculated by meta-analysis, and biomarkers were ranked according to pooled odds ratio.

DATA SYNTHESIS

Fifty-four studies appeared eligible for meta-analysis, together including 3,753 patients. We identified 20 biomarkers for diagnosis of acute respiratory distress syndrome in the at-risk population and 19 biomarkers for mortality of acute respiratory distress syndrome patients. The biomarkers most strongly associated with acute respiratory distress syndrome diagnosis in the at-risk population, when increased, were Krebs von den Lungen-6 (odds ratio [95% CI], 6.1 [3.0-12.1]), lactate dehydrogenase (5.7 [1.7-19.1]), soluble receptor for advanced glycation end products (3.5 [1.7-7.2]), and von Willebrand Factor (3.1 [2.0-5.2]). The biomarkers most strongly associated with acute respiratory distress syndrome mortality, when increased, were interleukin-4 (18.0 [6.0-54.2]), interleukin-2 (11.8 [4.3-32.2]), angiopoietin-2 (6.4 [1.3-30.4]), and Krebs von den Lungen-6 (5.1 [3.0-12.2]). Decreased levels of Protein C were associated with increased odds for acute respiratory distress syndrome diagnosis and mortality.

CONCLUSIONS

This meta-analysis provides a unique ranking of plasma biomarkers according to their strength of association with acute respiratory distress syndrome diagnosis or acute respiratory distress syndrome mortality. The relative performance of biomarkers among studies shown in this ranking may help to improve acute respiratory distress syndrome diagnosis and outcome prediction.

Human adult bone marrow-derived stem cells decrease severity of lipopolysaccharide-induced acute respiratory distress syndrome in sheep

INTRODUCTION

Acute respiratory distress syndrome (ARDS) is the most common cause of respiratory failure among critically ill subjects, sepsis and severe bacterial pneumonia being its most common causes. The only interventions that have proven beneficial are protective ventilation strategies and fluid conservation approaches. New therapies are needed to address this common clinical problem. Others and we have previously shown the beneficial effect of infusion of exogenous adult stem cells in different pre-clinical models of ARDS.

METHODS

In the present study endotoxin was infused intravenously into 14 sheep from which 6 received different doses of adult stem cells by intrabronchial delivery to evaluate the effect of stem cell therapy.

RESULTS

After administration of endotoxin, there was a rapid decline in oxygenation to hypoxemic values, indicative of severe-to-moderate ARDS. None of the animals treated with saline solution recovered to normal baseline values during the 6 hours that the animals were followed. In contrast, sheep treated with a dose of 40 million adult stem cells returned their levels of oxygen in their blood to baseline two hours after the cells were infused. Similarly, improvements in carbon dioxide (CO2) clearance, pulmonary vascular pressures and inflammation were observed and confirmed by histology and by the decrease in lung edema.

CONCLUSIONS

We concluded that instillation of adult non-hematopoietic stem cells can diminish the impact of endotoxin and accelerate recovery of oxygenation, CO2 removal and inflammation in the ovine model, making the use of adult stem cells a real alternative for future therapies for ARDS.

Clinical study of critical patients with hemorrhagic fever with renal syndrome complicated by acute respiratory distress syndrome

Objectives

The aim of this study was to investigate the clinical characteristics and outcomes of critical patients with hemorrhagic fever with renal syndrome (HFRS) complicated by acute respiratory distress syndrome (ARDS).

Materials and Methods

To observe the demographic, epidemiological and clinical characteristics, and to explore the predictive effects for prognosis in laboratory findings, we conducted a detailed retrospective analysis of clinical records for critical patients with HFRS complicated by ARDS, treated at the center for infectious diseases, Tangdu Hospital, between January 2008 and December 2012.

Results

A total of 48 critical patients with laboratory confirmed HFRS accompanied by ARDS were enrolled in the study, including 27 survivors and 21 non-survivors, with a fatality rate of 43.75%. Thirty-one individuals (64.6%) contracted HFRS between the months of September and December. The non-survivors tended to have lower incidence of overlapping phase (P = 0.025). There were no obvious differences in the needs for mechanical ventilation (MV) and renal replacement therapy (RRT), except for the need for vasoactive drugs between the survivors and non-survivors (P = 0.001). The non-survivors were found to have higher frequencies of encephalopathy, refractory shock and multiple organ dysfunction syndrome (MODS), lower incidences of acute renal failure (ARF) and secondary hypertension (P<0.05). The non-survivors tended to have lower levels of serum creatinine (Scr) (P<0.001) and fibrinogen (Fib) (P = 0.003), higher incidences of prolonged prothrombin time (PT) (P = 0.006) and activated partial thromboplastin time (APTT) (P = 0.020) and higher levels of aspartate aminotransferase (AST) (P = 0.015), and the laboratory parameters mentioned above reached statistical significance for predicting prognosis (P<0.05).

Conclusion

The high mortality rate of critical patients with HFRS complicated by ARDS emphasizes the importance of clinicians’ alertness and timely initiation of systemic supportive therapy.

Nano-engineered erythrocyte ghosts as inhalational carriers for delivery of fasudil: preparation and characterization

PURPOSE

Nanoerythrosomes (NERs), an engineered derivative of erythrocytes, have long been used as drug delivery carriers. These cell based carriers are biocompatible and biodegradable, and they exhibit efficient drug loading, targeting specificity and prolonged biological half-life. In this study, we have evaluated the feasibility of NERs as inhalable carriers for delivery of fasudil, an investigational drug for the treatment of pulmonary arterial hypertension.

METHODS

We prepared NERs by hypotonic lysis of erythrocytes derived from rat blood followed by extrusion through polycarbonate membranes. The formulations were optimized and characterized for size, morphology, entrapment efficiency, stability, cellular uptake and in-vitro release profiles followed by monitoring of drug absorption and safety evaluation after intratracheal administration of fasudil-loaded NERs into rats.

RESULTS

NERs were spherical in shape with an average size of 154.1 ± 1.31 nm and the drug loading efficiency was 48.76 ± 2.18%. Formulations were stable when stored at 4°C for 3 weeks. When incubated with rat pulmonary arterial smooth muscle cells (PASM), a significant amount of NERs was taken up by PASM cells. The drug encapsulated in NERs inhibited the rho-kinase activity upto 50%, which was comparable with the plain fasudil. A ~6-8 fold increase in the half-life of fasudil was observed when encapsulated in NERs.

CONCLUSION

This study suggests that nanoerythrosomes can be used as cell derived carriers for inhalational delivery of fasudil.

Potential effects of medicinal plants and secondary metabolites on acute lung injury

Acute lung injury (ALI) is a life-threatening syndrome that causes high morbidity and mortality worldwide. ALI is characterized by increased permeability of the alveolar-capillary membrane, edema, uncontrolled neutrophils migration to the lung, and diffuse alveolar damage, leading to acute hypoxemic respiratory failure. Although corticosteroids remain the mainstay of ALI treatment, they cause significant side effects. Agents of natural origin, such as medicinal plants and their secondary metabolites, mainly those with very few side effects, could be excellent alternatives for ALI treatment. Several studies, including our own, have demonstrated that plant extracts and/or secondary metabolites isolated from them reduce most ALI phenotypes in experimental animal models, including neutrophil recruitment to the lung, the production of pro-inflammatory cytokines and chemokines, edema, and vascular permeability. In this review, we summarized these studies and described the anti-inflammatory activity of various plant extracts, such as Ginkgo biloba and Punica granatum, and such secondary metabolites as epigallocatechin-3-gallate and ellagic acid. In addition, we highlight the medical potential of these extracts and plant-derived compounds for treating of ALI.

Novel concepts of acute lung injury and alveolar-capillary barrier dysfunction

In this review we summarize recent major advances in our understanding on the molecular mechanisms, mediators, and biomarkers of acute lung injury (ALI) and alveolar-capillary barrier dysfunction, highlighting the role of immune cells, inflammatory and noninflammatory signaling events, mechanical noxae, and the affected cellular and molecular entities and functions. Furthermore, we address novel aspects of resolution and repair of ALI, as well as putative candidates for treatment of ALI, including pharmacological and cellular therapeutic means.

Total flavonoids of Mosla scabra leaves attenuates lipopolysaccharide-induced acute lung injury via down-regulation of inflammatory signaling in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Mosla scabra (Thunb.) C.Y. Wu, belonging to the Labiatae family, is a tomentose and aromatic plant, which is widely used as an antipyretic and antiviral drug for pulmonary diseases and famous for its efficiency in treating colds, fever, pneumonia and chronic bronchitis. To investigate therapeutic effects and possible mechanism of Mosla scabra flavonoids (MF) on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice.

MATERIALS AND METHODS

Mice were orally administrated with MF once (30 mg/kg or 90 mg/kg) 1 h before LPS challenge. Lung specimens and the bronchoalveolar lavage fluid (BALF) were isolated for histopathological examinations and biochemical analyses 6 h after LPS challenge.

RESULTS

Pretreatment with MF could decrease significantly lung wet-to-dry weight (W/D) ratio, lower myeloperoxidase (MPO) activity and total protein concentrations in the BALF, reduce serum levels of NO, TNF-α, IL-1β and IL-6 in ALI model. Additionally, MF attenuated lung histopathological changes and significantly inhibited the phosphorylation of p38 MAPK and translocation of NF-κB p65.

CONCLUSIONS

These results showed MF significantly attenuate LPS-induced acute lung injury and production of inflammatory mediators via inhibiting MAPK and NF-κB activation, indicating it as a potential therapeutic agent for ALI.

Redox markers and inflammation are differentially affected by atorvastatin, pravastatin or simvastatin administered before endotoxin-induced acute lung injury

Statins are standard therapy for the treatment of lipid disorders, and the field of redox biology accepts that statins have antioxidant properties. Our aim in this report was to consider the pleiotropic effects of atorvastatin, pravastatin and simvastatin administered prior to endotoxin-induced acute lung injury. Male mice were divided into 5 groups and intraperitoneally injected with LPS (10 mg/kg), LPS plus atorvastatin (10 mg/kg/day; A + LPS group), LPS plus pravastatin (5 mg/kg/day; P + LPS group) or LPS plus simvastatin (20 mg/kg/day; S + LPS group). The control group received saline. All mice were sacrificed one day later. There were fewer leukocytes in the P + LPS and S + LPS groups than in the LPS group. MCP-1 cytokine levels were lower in the P + LPS group, while IL-6 levels were lower in the P + LPS and S + LPS groups. TNF-α was lower in all statin-treated groups. Levels of redox markers (superoxide dismutase and catalase) were lower in the A + LPS group (p < 0.01). The extent of lipid peroxidation (malondialdehyde and hydroperoxides) was reduced in all statin-treated groups (p < 0.05). Myeloperoxidase was lower in the P + LPS group (p < 0.01). Elastance levels were significantly greater in the LPS group compared to the statin groups. Our results suggest that atorvastatin and pravastatin but not simvastatin exhibit anti-inflammatory and antioxidant activity in endotoxin-induced acute lung injury.