Ginsenoside Rg1 Alleviates Sepsis-Induced Acute Lung Injury by Reducing FBXO3 Stability in an m6A-Dependent Manner to Activate PGC-1α/Nrf2 Signaling Pathway

BACKGROUND

Sepsis-induced acute lung injury (ALI) is one of the serious life-threatening complications of sepsis and is pathologically associated with mitochondrial dysfunction. Ginsenoside Rg1 has good therapeutic effects on ALI. Herein, the pharmacological effects of Rg1 in sepsis-induced ALI were investigated.

METHODS

Sepsis-induced ALI models were established by CLP operation and LPS treatment. HE staining was adopted to analyze lung pathological changes. The expression and secretion of cytokines were measured by RT-qPCR and ELISA. Cell viability and apoptosis were assessed by MTT assay, flow cytometry and TUNEL staining. ROS level and mitochondrial membrane potential (MMP) were analyzed using DHE probe and JC-1 staining, respectively. FBXO3 m6A level was assessed using MeRIP assay. The interactions between FBXO3, YTHDF1, and PGC-1α were analyzed by Co-IP or RIP.

RESULTS

Rg1 administration ameliorated LPS-induced epithelial cell inflammation, apoptosis, and mitochondrial dysfunction in a dose-dependent manner. Mechanically, Rg1 reduced PGC-1α ubiquitination modification level by inhibiting FBXO3 expression m6A-YTHDF1 dependently. As expected, Rg1's mitigative effect on LPS-induced inflammation, apoptosis and mitochondrial dysfunction in lung epithelial cells was abolished by FBXO3 overexpression. Moreover, FBXO3 upregulation eliminated the restoring effect of Rg1 on CLP-induced lung injury in rats.

CONCLUSION

Rg1 activated PGC-1α/Nrf2 signaling pathway by reducing FBXO3 stability in an m6A-YTHDF1-dependent manner to improve mitochondrial function in lung epithelial cells during sepsis-induced ALI progression.

Photobiomodulation with 630-nm LED Inhibits M1 Macrophage Polarization via STAT1 Pathway Against Sepsis-Induced Acute Lung Injury

Background: Sepsis-induced acute lung injury (ALI) is a clinical syndrome characterized by excessive uncontrolled inflammation. Photobiomodulation such as light-emitting diode (LED) irradiation has been used to attenuate inflammatory disease. Objective: The protective effect of 630 nm LED irradiation on sepsis-induced ALI remains unknown. The purpose of this study was to investigate the role of 630 nm LED irradiation in sepsis-induced ALI and its underlying mechanism. Methods and results: C57BL/6 mice were performed cecal ligation and puncture (CLP) for 12 h to generate experimental sepsis models. Histopathology analysis showed that alveolar injury, inflammatory cells infiltration, and hemorrhage were suppressed in CLP mice after 630 nm LED irradiation. The ratio of wet/dry weigh of lung tissue was significantly inhibited by irradiation. The number of leukocytes was reduced in bronchoalveolar lavage fluid. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) results and enzyme-linked immunosorbent assay showed that 630 nm LED irradiation significantly inhibited the mRNA and protein levels of M1 macrophage-related genes in the lung of CLP-induced septic mice. Meanwhile, LED irradiation significantly inhibited signal transducer and activator of transcription 1 (STAT1) phosphorylation in the lung of septic mice. In vitro experiments showed that 630 nm LED irradiation significantly inhibited M1 genes mRNA and protein expression in THP-1-derived M1 macrophages without affecting the cell viability. LED irradiation also significantly inhibited the level of STAT1 phosphorylation in THP-1-derived M1 macrophages. Conclusions: We concluded that 630 nm LED is promising as a treatment against ALI through inhibiting M1 macrophage polarization, which is associated with the downregulation of STAT1 phosphorylation.

Sodium butyrate ameliorates sepsis-associated lung injury by enhancing gut and lung barrier function in combination with modulation of CD4+Foxp3+ regulatory T cells

Sepsis-associated lung injury often coexists with intestinal dysfunction. Butyrate, an essential gut microbiota metabolite, participates in gut-lung crosstalk and has immunoregulatory effects. This study aims to investigate the effect and mechanism of sodium butyrate (NaB) on lung injury. Sepsis-associated lung injury was established in mice by cecal ligation and puncture (CLP). Mice in treatment groups received NaB gavage after surgery. The survival rate, the oxygenation index and the lung wet-to-dry weight (W/D) ratio were calculated respectively. Pulmonary and intestinal histologic changes were observed. The total protein concentration in bronchoalveolar lavage fluid (BALF) was measured, and inflammatory factors in serum and BALF were examined. Diamine oxidase (DAO), lipopolysaccharide (LPS), and surfactant-associated protein D (SP-D) levels in serum and amphiregulin in lung tissue were assessed. Intercellular junction protein expression in the lung and intestinal tissues were examined. Changes in immune cells were analyzed. NaB treatment improved the survival rate, the oxygenation index and the histologic changes. NaB decreased the W/D ratio, total protein concentration, and the levels of proinflammatory cytokines, as well as SP-D, DAO and LPS, while increased the levels of anti-inflammatory cytokines and amphiregulin. The intercellular junction protein expression were improved by NaB. Furthermore, the CD4+/CD8+ T-cell ratio and the proportion of CD4+Foxp3+ regulatory T cells (Tregs) were increased by NaB. Our data suggested that NaB gavage effectively improved the survival rate and mitigated lung injury in CLP mice. The possible mechanism was that NaB augmented CD4+Foxp3+ Tregs and enhanced the barrier function of the gut and the lung.

Hyperoxia for sepsis and development of acute lung injury with increased mortality

BACKGROUND

Supraphysiological oxygen administration causes unfavourable clinical outcomes in various diseases. This study aimed to determine whether hyperoxia would be associated with increased mortality in patients with severe infection.

METHODS

A post-hoc analysis of a nationwide multicentre prospective observational study on sepsis (SPICE Study) was conducted, including adult patients admitted to the intensive care unit with available arterial partial pressure of oxygen (PaO2) at the treatment initiation for severe infection. Hyperoxia was defined as a PaO2 level of ≥300 mm Hg and in-hospital mortality was compared between patients with and without hyperoxia.

RESULTS

Of the 563 patients eligible for the study, 49 had hyperoxia at treatment initiation for severe infection. The in-hospital all-cause mortality rates of patients with and without hyperoxia were 14 (29.2%) and 90 (17.6%), respectively. Inverse probability weighting analyses with propensity scores revealed the association between hyperoxia and increased in-hospital mortality rate (28.8% vs 18.8%; adjusted OR 1.75 (1.03 to 2.97); p=0.038), adjusting for patient demographics, comorbidities, site of infection, severity of infection, haemodynamic and respiratory status, laboratory data and location of patient at infection development. Acute lung injury developed more frequently in patients with hyperoxia on the following days after infection treatment, whereas sepsis-related mortality was comparable regardless of hyperoxia exposure.

CONCLUSION

Hyperoxia with PaO2 ≥300 mm Hg at treatment initiation of severe infection was associated with an increased in-hospital mortality rate in patients requiring intensive care. The amount of oxygen to administer to patients with severe infection should be carefully determined.

TRIAL REGISTRATION NUMBER

University Hospital Medical Information Network Clinical Trial Registry (UMIN000027452).

N6-methyladenosine modification: Regulatory mechanisms and therapeutic potential in sepsis

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection and is characterized by multiple biological and clinical features. N6-methyladenosine (m6A) modification is the most common type of RNA modifications in eukaryotes and plays an important regulatory role in various biological processes. Recently, m6A modification has been found to be involved in the regulation of immune responses in sepsis. In addition, several studies have shown that m6A modification is involved in sepsis-induced multiple organ dysfunctions, including cardiovascular dysfunction, acute lung injury (ALI), acute kidney injury (AKI) and etc. Considering the complex pathogenesis of sepsis and the lack of specific therapeutic drugs, m6A modification may be the important bond in the pathophysiological process of sepsis and even therapeutic targets. This review systematically highlights the recent advances regarding the roles of m6A modification in sepsis and sheds light on their use as treatment targets for sepsis.

Effects of the PI3K/Akt/HO-1 pathway on autophagy in a sepsis-induced acute lung injury mouse model

Sepsis-induced lung injury is an acute hypoxic respiratory insufficiency caused by systemic infectious factors that results in alveolar epithelial cell and capillary endothelial cell injury, diffuse pulmonary interstitial edema, and alveolar edema. Heme oxygenase (HO)-1 is usually associated with inflammation and has anti-inflammatory effects. Autophagy is a degradation pathway that eliminates cellular metabolic waste and plays an important protective role during stress. The phosphatidylinositol 3-kinase/ protein kinase B (PI3K/Akt) signaling pathway plays a key role in mediating cellular responses to inflammatory reactions. Therefore, we hypothesized that HO-1 is associated with autophagy and regulated by the PI3K/Akt signaling pathway in mice with sepsis-induced lung injury. Sepsis-induced lung injury was induced in mice using cecal ligation and puncture (CLP). Hemin or Sn-protoporphyrin IX (SnPP) was administered via intraperitoneal injection before surgery. Survival rates were observed during days 1-7 after the surgery; lung histology was discerned 24 h after the surgery; pro-inflammatory and anti-inflammatory factors in plasma and lung tissue were measured using enzyme-linked immunosorbent assay (ELISA); HO-1, Beclin-1, microtubule-associated protein 1 light chain 3B (LC3B)-II, p62 and lysosome associated membrane protein (LAMP)2 protein expression levels were measured 24 h after the surgery; HO-1 and LC3B-II protein expression levels were observed using immunofluorescence 24 h after the surgery; and autophagosomes were detected using electron microscopy 24 h after the surgery. Furthermore, when PI3K inhibitors LY294002, PI3K activators Recilisib and hemin were administered before the surgery, Akt, p-Akt, HO-1, and LC3-II levels were measured 24 h post-surgery. We found that HO-1 overexpression increased the survival rate and inhibited sepsis-induced lung injury. HO-1 overexpression attenuated the levels of proinflammatory cytokines (TNF-α, IL-1β) and increased the anti-inflammatory cytokine (IL-10, HO-1) overexpression. Moreover, HO-1 overexpression was also associated with increased expression of Beclin-1, LC3B-II and LAMP2 protein expression; decreased p62 protein expression; and significantly increased autophagosome formation. The results for HO-1-downregulated mice contrasted with those mentioned above. LY294002 inhibited p-Akt/Akt, HO-1, and LC3B-II protein expression; and hemin reversed the inhibitory effect of LY294002. The protective effect of HO-1 was involved in the mediation of autophagy, which may be regulated by the PI3K/Akt signaling pathway during sepsis-induced lung injury in mice.

Effects of nebulized adipose-derived mesenchymal stem cells on acute lung injury following smoke inhalation in sheep

INTRODUCTION

Treatment of ARDS caused by smoke inhalation is challenging with no specific therapies available. The aim of this study was to test the efficacy of nebulized adipose-derived mesenchymal stem cells (ASCs) in a well-characterized, clinically relevant ovine model of smoke inhalation injury.

MATERIAL AND METHODS

Fourteen female Merino sheep were surgically instrumented 5-7 days prior to study. After induction of acute lung injury (ALI) by cooled cotton smoke insufflation into the lungs (under anesthesia and analgesia), sheep were placed on a mechanical ventilator for 48 hrs and monitored for cardiopulmonary hemodynamics in a conscious state. ASCs were isolated from ovine adipose tissue. Sheep were randomly allocated to two groups after smoke injury: 1) ASCs group (n = 6): 10 million ASCs were nebulized into the airway at 1 hr post-injury; and 2) Control group (n = 8): Nebulized with saline into the airways at 1 hr post-injury. ASCs were labeled with green fluorescent protein (GFP) to trace cells within the lung. ASCs viability was determined in bronchoalveolar lavage fluid (BALF).

RESULTS

PaO2/FiO2 in the ASCs group was significantly higher than in the control group (p = 0.001) at 24 hrs. Oxygenation index: (mean airway pressure × FiO2/PaO2) was significantly lower in the ASCs group at 36 hr (p = 0.003). Pulmonary shunt fraction tended to be lower in the ASCs group as compared to the control group. GFP-labelled ASCs were found on the surface of trachea epithelium 48 hrs after injury. The viability of ASCs in BALF was significantly lower than those exposed to the control vehicle solution.

CONCLUSION

Nebulized ASCs moderately improved pulmonary function and delayed the onset of ARDS.

Glucocorticoid Treatment in Acute Respiratory Distress Syndrome: An Overview on Mechanistic Insights and Clinical Benefit

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS), triggered by various pathogenic factors inside and outside the lungs, leads to diffuse lung injury and can result in respiratory failure and death, which are typical clinical critical emergencies. Severe acute pancreatitis (SAP), which has a poor clinical prognosis, is one of the most common diseases that induces ARDS. When SAP causes the body to produce a storm of inflammatory factors and even causes sepsis, clinicians will face a two-way choice between anti-inflammatory and anti-infection objectives while considering the damaged intestinal barrier and respiratory failure, which undoubtedly increases the difficulty of the diagnosis and treatment of SAP-ALI/ARDS. For a long time, many studies have been devoted to applying glucocorticoids (GCs) to control the inflammatory response and prevent and treat sepsis and ALI/ARDS. However, the specific mechanism is not precise, the clinical efficacy is uneven, and the corresponding side effects are endless. This review discusses the mechanism of action, current clinical application status, effectiveness assessment, and side effects of GCs in the treatment of ALI/ARDS (especially the subtype caused by SAP).

Histopathologic and Immunohistochemical Assessment of Acute Respiratory Distress Syndrome (ARDS): Challenges and Complexities of Postmortem Diagnosis

Acute respiratory distress syndrome (ARDS) is a life-threatening condition due to acute lung injury (ALI), characterized by rapid-onset respiratory failure, leading to the clinical manifestations of poor lung compliance, severe hypoxemia, and dyspnea. ARDS/ALI has many causes, most commonly related to infections (sepsis, pneumonia), traumas, and multiple transfusions. The objective of this study is to assess the performance of postmortem anatomopathological examination in identifying etiological agents associated with ARDS or ALI in deceased patients from the State of São Paulo from 2017 to 2018. A retrospective cross-sectional study was performed based on the final outcome obtained by histopathology, histochemical, and immunohistochemical examination for ARDS/ALI differential diagnosis at the Pathology Center of the Adolfo Lutz Institute in São Paulo, Brazil. Of the 154 patients clinically diagnosed with ARDS or ALI, 57% tested positive for infectious agents, and the most frequent outcome was influenza A/H1N1 virus infection. In 43% of cases, no etiologic agent was identified. The opportunity to establish a diagnosis, identify particular infections, confirm a microbiological diagnosis, and uncover unanticipated etiologies is provided by postmortem pathologic analysis of ARDS. A molecular assessment could improve the diagnosis accuracy and lead to research into host responses and public health measures.

Gut microbiota-derived succinate aggravates acute lung injury after intestinal ischaemia/reperfusion in mice

INTRODUCTION

Acute lung injury (ALI) is a major cause of morbidity and mortality after intestinal ischaemia/reperfusion (I/R). The gut microbiota and its metabolic byproducts act as important modulators of the gut-lung axis. This study aimed to define the role of succinate, a key microbiota metabolite, in intestinal I/R-induced ALI progression.

METHODS

Gut and lung microbiota of mice subjected to intestinal I/R were analysed using 16S rRNA gene sequencing. Succinate level alterations were measured in germ-free mice or conventional mice treated with antibiotics. Succinate-induced alveolar macrophage polarisation and its effects on alveolar epithelial apoptosis were evaluated in succinate receptor 1 (Sucnr1)-deficient mice and in murine alveolar macrophages transfected with Sucnr1-short interfering RNA. Succinate levels were measured in patients undergoing cardiopulmonary bypass, including intestinal I/R.

RESULTS

Succinate accumulated in lungs after intestinal I/R, and this was associated with an imbalance of succinate-producing and succinate-consuming bacteria in the gut, but not the lungs. Succinate accumulation was absent in germ-free mice and was reversed by gut microbiota depletion with antibiotics, indicating that the gut microbiota is a source of lung succinate. Moreover, succinate promoted alveolar macrophage polarisation, alveolar epithelial apoptosis and lung injury during intestinal I/R. Conversely, knockdown of Sucnr1 or blockage of SUCNR1 in vitro and in vivo reversed the effects of succinate by modulating the phosphoinositide 3-kinase-AKT/hypoxia-inducible factor-1α pathway. Plasma succinate levels significantly correlated with intestinal I/R-related lung injury after cardiopulmonary bypass.

CONCLUSION

Gut microbiota-derived succinate exacerbates intestinal I/R-induced ALI through SUCNR1-dependent alveolar macrophage polarisation, identifying succinate as a novel target for gut-derived ALI in critically ill patients.

Acute lung injury and recovery in patients with refractory VT/VF cardiac arrest treated with prolonged CPR and veno-arterial extracorporeal membrane oxygenation

AIM

Describe the lung injury patterns among patients presenting with refractory ventricular tachycardia/ventricular fibrillation out-of-hospital cardiac arrest (VT/VF OHCA) supported with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) facilitated resuscitation.

METHODS

In this retrospective single-center cohort study including VT/VF OHCA patients supported with VA ECMO, we compared OHCA characteristics, post-arrest computed tomography (CT) scans, ventilator parameters, and other lung-related pathology between survivors, patients who developed brain death, and those with other causes of death.

RESULTS

Among 138 patients, 48/138 (34.8%) survived, 31/138 (22.4%) developed brain death, and 59/138 (42.7%) died of other causes. Successful extubation was achieved in 39/138 (28%) with a median time to extubation of 8.0 days (6.0, 11.0) in those who survived. Tracheostomy was required in 15/48 (31.3%) survivors. Chest CT obtained on all patients showed lung injury in at least one lung area in 124/135 (91.8%) patients, predominantly in the dependent posterior areas. There was no association between the number of affected areas and survival. Lung compliance was low on admission [26 (19,33) ml/cmH₂0], improved throughout hospitalization (p = 0.03), and recovered faster in survivors compared to those who died (p < 0.001). VA-ECMO allowed the use of lung-protective ventilation while maintaining normalized PaO₂ and PaCO₂. Patients treated with V-A ECMO and either IABP or Impella had lower pulmonary compliance and more affected areas on their CT compared to those treated with V-A ECMO alone.

CONCLUSIONS

Lung injury is common among patients with refractory VT/VF OHCA requiring V-A ECMO, but imaging severity is not associated with survival. Reductions in lung compliance accompany post-arrest lung injury while compliance recovery is associated with survival.

Acute lung injury in a worker after inhalation of ethylene phosphorodifluoridite

Ethylene phosphorodifluoridite (C2H4F4O2P2) (CAS No. 3965-00-2) is a colorless corrosive fuming liquid that is used as a stabilizer in the electrolyte of rechargeable batteries. There are no previous reports of toxic effects following exposure to this compound. A 28-year-old male complained of respiratory distress after accidental inhalation of ethylene phosphorodifluoridite for 30 min. The patient developed acute lung injury with noncardiogenic pulmonary edema and was treated with supportive management. The patient fully recovered and was discharged after 7 days without any significant sequelae. The patient's symptoms were attributed to non-cardiogenic pulmonary edema caused by ethylene phosphorodifluoridite exposure. The case study showed that ethylene phosphorodifluoridite should be added to the list of chemicals that can cause acute lung injury. Int J Occup Med Environ Health. 2022;35(3):361-6.

Endogenous Sulfur Dioxide Improves the Survival Rate of Sepsis by Improving the Oxidative Stress Response during Lung Injury

Objective

To explore the regulation of endogenous sulfur dioxide on oxidative stress in lung injury induced by sepsis.

Method

Forty male Sprague Dawley rats were divided into control, sepsis, sepsis + SO2, and SO2 group randomly used to observe survival rate. The other group of twenty-eight rats were randomly divided as the same manner for mechanism research. The number of WBCS and the percentage of PMN cells were calculated. The microphotographs of morphological changes and the index of quantitative assessment (IQA) of lung tissues were calculated. The ratio of wet/dry (W/D) of lung tissues was calculated. Levels of H2O2, MDA, NO, MPO, SOD, GSH-px, and TNF-α in plasma and lung tissues were measured.

Result

The number of WBCS and the percentage of PMN cells decreased in sepsis (p all < 0.05), and rebound in sepsis+SO2 (p all < 0.05). The IQA and W/D of lung tissues increased in sepsis (p for W/D < 0.05), and decreased in sepsis+SO2 (p all < 0.05). H2O2 and MDA of plasma and lung tissues increased in sepsis (p all < 0.05) and rebound in sepsis+SO2 (p for H2O2 of plasma and lung tissues <0.05). NO and MPO of plasma and lung tissues increased in sepsis (p for NO and MPO of lung tissues <0.05) and rebound in sepsis+SO2 (p all < 0.05). SOD of plasma and lung tissues in sepsis group decreased (p all <0.05) and increased in sepsis+SO2 (p all < 0.05). GSH-px of plasma and lung tissues decreased in sepsis (p for plasma <0.05) and increased in sepsis+SO2 (p for GSH-px of lung tissues <0.05). TNF-α of plasma and lung tissues increased in sepsis (p all<0.05) and decreased in sepsis+SO2 (p for lung tissue <0.05).

Conclusion

Endogenous sulfur dioxide improves the survival rate of sepsis by improving the oxidative stress response during lung injury.

Identification of kidney injury released circulating osteopontin as causal agent of respiratory failure

Tissue injury can drive secondary organ injury; however, mechanisms and mediators are not well understood. To identify interorgan cross-talk mediators, we used acute kidney injury (AKI)-induced acute lung injury (ALI) as a clinically important example. Using kidney and lung single-cell RNA sequencing after AKI in mice followed by ligand-receptor pairing analysis across organs, kidney ligands to lung receptors, we identify kidney-released circulating osteopontin (OPN) as a novel AKI-ALI mediator. OPN release from kidney tubule cells triggered lung endothelial leakage, inflammation, and respiratory failure. Pharmacological or genetic OPN inhibition prevented AKI-ALI. Transplantation of ischemic wt kidneys caused AKI-ALI, but not of ischemic OPN-global knockout kidneys, identifying kidney-released OPN as necessary interorgan signal to cause AKI-ALI. We show that OPN serum levels are elevated in patients with AKI and correlate with kidney injury. Our results demonstrate feasibility of using ligand-receptor analysis across organs to identify interorgan cross-talk mediators and may have important therapeutic implications in human AKI-ALI and multiorgan failure.

Mesenchymal stromal cell-derived extracellular vesicles reduce lung inflammation and damage in nonclinical acute lung injury: Implications for COVID-19

Mesenchymal stem cell derived extracellular vesicles (MSC-EVs) are bioactive particles that evoke beneficial responses in recipient cells. We identified a role for MSC-EV in immune modulation and cellular salvage in a model of SARS-CoV-2 induced acute lung injury (ALI) using pulmonary epithelial cells and exposure to cytokines or the SARS-CoV-2 receptor binding domain (RBD). Whereas RBD or cytokine exposure caused a pro-inflammatory cellular environment and injurious signaling, impairing alveolar-capillary barrier function, and inducing cell death, MSC-EVs reduced inflammation and reestablished target cell health. Importantly, MSC-EV treatment increased active ACE2 surface protein compared to RBD injury, identifying a previously unknown role for MSC-EV treatment in COVID-19 signaling and pathogenesis. The beneficial effect of MSC-EV treatment was confirmed in an LPS-induced rat model of ALI wherein MSC-EVs reduced pro-inflammatory cytokine secretion and respiratory dysfunction associated with disease. MSC-EV administration was dose-responsive, demonstrating a large effective dose range for clinical translation. These data provide direct evidence of an MSC-EV-mediated improvement in ALI and contribute new insights into the therapeutic potential of MSC-EVs in COVID-19 or similar pathologies of respiratory distress.

Deficiency of AMPKα1 Exacerbates Intestinal Injury and Remote Acute Lung Injury in Mesenteric Ischemia and Reperfusion in Mice

Mesenteric ischemia and reperfusion (I/R) injury can ensue from a variety of vascular diseases and represents a major cause of morbidity and mortality in intensive care units. It causes an inflammatory response associated with local gut dysfunction and remote organ injury. Adenosine monophosphate-activated protein kinase (AMPK) is a crucial regulator of metabolic homeostasis. The catalytic α1 subunit is highly expressed in the intestine and vascular system. In loss-of-function studies, we investigated the biological role of AMPKα1 in affecting the gastrointestinal barrier function. Male knock-out (KO) mice with a systemic deficiency of AMPKα1 and wild-type (WT) mice were subjected to a 30 min occlusion of the superior mesenteric artery. Four hours after reperfusion, AMPKα1 KO mice exhibited exaggerated histological gut injury and impairment of intestinal permeability associated with marked tissue lipid peroxidation and a lower apical expression of the junction proteins occludin and E-cadherin when compared to WT mice. Lung injury with neutrophil sequestration was higher in AMPKα1 KO mice than WT mice and paralleled with higher plasma levels of syndecan-1, a biomarker of endothelial injury. Thus, the data demonstrate that AMPKα1 is an important requisite for epithelial and endothelial integrity and has a protective role in remote organ injury after acute ischemic events.

Ruscogenin attenuates particulate matter-induced acute lung injury in mice via protecting pulmonary endothelial barrier and inhibiting TLR4 signaling pathway

The inhalation of particulate matter (PM) is closely related to respiratory damage, including acute lung injury (ALI), characterized by inflammatory fluid edema and disturbed alveolar-capillary permeability. Ruscogenin (RUS), the main active ingredient in the traditional Chinese medicine Ophiopogonis japonicus, has been found to exhibit anti-inflammatory activity and rescue LPS-induced ALI. In this study, we investigated whether and how RUS exerted therapeutic effects on PM-induced ALI. RUS (0.1, 0.3, 1 mg·kg-1·d-1) was orally administered to mice prior to or after intratracheal instillation of PM suspension (50 mg/kg). We showed that RUS administration either prior to or after PM challenge significantly attenuated PM-induced pathological injury, lung edema, vascular leakage and VE-cadherin expression in lung tissue. RUS administration significantly decreased the levels of cytokines IL-6 and IL-1β, as well as the levels of NO and MPO in both bronchoalveolar lavage fluid (BALF) and serum. RUS administration dose-dependently suppressed the phosphorylation of NF-κB p65 and the expression of TLR4 and MyD88 in lung tissue. Furthermore, TLR4 knockout partly diminished PM-induced lung injury, and abolished the protective effects of RUS in PM-instilled mice. In conclusion, RUS effectively alleviates PM-induced ALI probably by inhibition of vascular leakage and TLR4/MyD88 signaling. TLR4 might be crucial for PM to initiate pulmonary lesion and for RUS to exert efficacy against PM-induced lung injury.

Key Pathogenic Factors in Coronavirus Disease 2019-Associated Coagulopathy and Acute Lung Injury Highlighted in a Patient With Copresentation of Acute Myelocytic Leukemia: A Case Report

The role of concurrent illness in coronavirus disease 2019 (COVID-19) is unknown. Patients with leukemia may display altered thromboinflammatory responses. We report a 53-year-old man presenting with acute leukemia and COVID-19 who developed thrombotic complications and acute respiratory distress syndrome. Multiple analyses, including rotational thromboelastometry and flow cytometry on blood and bronchoalveolar lavage, are reported to characterize coagulation and immune profiles. The patient developed chemotherapy-induced neutropenia that may have protected his lungs from granulocyte-driven hyperinflammatory acute lung injury. However, neutropenia also alters viral clearing, potentially enabling ongoing viral propagation. This case depicts a precarious equilibrium between leukemia and COVID-19.

Waterproofing spray-associated pneumonitis review: Comparison with acute eosinophilic pneumonia and hypersensitivity pneumonitis

Waterproofing spray-associated pneumonitis (WAP) proceeds to acute respiratory failure and is characterized by diffuse bilateral ground-glass opacities on computed tomography; however, the detailed characteristics of WAP are unknown. Therefore, this study identified the characteristics of WAP from comparisons with those of acute eosinophilic pneumonia (AEP) and hypersensitivity pneumonitis (HP), which show similar features to WAP.Adult patients with WAP, AEP, and HP treated in Fukujuji Hospital from 1990 to 2018 were retrospectively enrolled. Furthermore, data from patients with WAP were collected from publications in PubMed and the Japan Medical Abstracts Society and combined with data from our patients.Thirty-three patients with WAP, eleven patients with AEP, and thirty patients with HP were reviewed. Regarding age, sex, smoking habit, and laboratory findings (white blood cell count, C-reactive protein level, and serum Krebs von den Lungen-6 level), WAP and AEP were not significantly different, while WAP and HP were significantly different. The duration from symptom appearance to hospital visit was shorter in patients with WAP (median 1 day) than in patients with AEP (median 3 days, P = .006) or HP (median 30 days, P < .001). The dominant cells in the bronchoalveolar lavage fluid of patients with WAP, AEP, and HP were different (macrophages, eosinophils, and lymphocytes, respectively).The characteristic features of WAP were rapid disease progression and macrophage dominance in the bronchoalveolar lavage fluid, and these characteristics can be used to distinguish among WAP, AEP, and HP.

Diesel Exhaust Particulates Enhances Susceptibility of LPS-Induced Acute Lung Injury through Upregulation of the IL-17 Cytokine-Derived TGF-β1/Collagen I Expression and Activation of NLRP3 Inflammasome Signaling in Mice

Diesel exhaust particulates (DEP) adversely affect the respiratory system and exacerbate lung diseases, resulting in high mortality rates. However, its pathogenesis is complicated, and the mechanisms involved are incompletely understood. We investigated the effects of DEP pre-exposure on lipopolysaccharide (LPS)-induced acute lung injury (ALI) and identified the roles of interleukin (IL)-17 in mice. Mice were divided into vehicle control, DEP, LPS, and DEP pre-exposed and LPS-instilled groups. Pre-exposure to DEP enhanced the number of total cells, neutrophils, and lymphocytes in the BAL fluid of LPS-instilled mice. Pre-exposure to DEP synergistically exacerbated pulmonary acute lung inflammation and granulomatous inflammation/pulmonary fibrosis, concomitant with the enhanced expression of inflammatory cytokines in the BAL fluid and of collagen I and TGF-β1 in the lungs of LPS-instilled mice. The number of TGF-β1-positive cells in the DEP pre-exposed and LPS-instilled group was higher than that in the LPS group. The expression of NLR family pyrin domain containing 3 (NLRP3) inflammasome components was markedly increased in the DEP pre-exposed and LPS-instilled group. IL-17 levels in the BAL fluid and IL-17-positive cells in the lungs were significantly increased by pre-exposure to DEP in the LPS-induced group compared to that in the DEP or LPS group. These results suggest that DEP predominantly contributes to fibrotic lung disease in LPS-related acute lung injury by upregulating IL-17 cytokine-mediated collagen I and TGF-β1 and, at least in part, by activating LPS-induced NLRP3 inflammasome signaling. The study should be useful in devising better strategies for prevention and management of ALI.

Adaptive support ventilation attenuates postpneumonectomy acute lung injury in a porcine model

OBJECTIVES

An optimal ventilation strategy that causes as little mechanical stress and inflammation as possible is critical for patients undergoing pneumonectomy. The aim of this study was to determine whether adaptive support ventilation (ASV) can provide protective ventilation to the remaining lung after pneumonectomy with minimal mechanical stress and less inflammation than volume-control ventilation (VCV).

METHODS

In this study, 15 pigs were randomly allocated to 3 groups (n = 5 for each group): the control group, the VCV group and the ASV group. After left pneumonectomy, the VCV group was treated with the volume-control set to 20 ml/kg, and the ASV group with the mode set to achieve 60% of the minute ventilation of 2 lungs.

RESULTS

The ASV group had lower alveolar strain than the VCV group. The ASV group exhibited less lung injury and greater alveolar fluid clearance than the VCV group (13.3% vs -17.8%; P ≤ 0.018). Ventilator-induced lung injury was associated with changes in the cytokine levels in the exhaled breath condensate, differential changes in plasma and changes in the cytokines in the bronchoalveolar lavage fluid. Expression of 3 microRNAs (miR449b-3p, P ≤ 0.001; miR451-5p, P = 0.027; and miR144-5p, P = 0.008) was increased in the VCV group compared with the ASV group.

CONCLUSIONS

The ASV mode was capable of supporting rapid, shallow breathing patterns to exert lung-protective effects in a porcine postpneumonectomy model. Further investigation of microRNAs as biomarkers of ventilator-induced lung injury is warranted.

Melatonin prevents LPS-induced epithelial-mesenchymal transition in human alveolar epithelial cells via the GSK-3β/Nrf2 pathway

BACKGROUND

Oxidative stress plays a critical role in pulmonary fibrosis after acute lung injury (ALI), and epithelial-mesenchymal transition (EMT) events are involved in this process. The purpose of this study was to investigate the protective effects of melatonin, a natural antioxidant, on lipopolysaccharide (LPS)-induced EMT in human alveolar epithelial cells.

METHODS

Human type II alveolar epithelial cell-derived A549 cells were incubated with LPS and melatonin alone or in combination for up to 24 h. The morphological changes of the treated cells were evaluated as well as indexes of oxidative stress. EMT-related proteins and the Nrf2 signaling pathway were detected by western blot analysis and immunofluorescence staining, respectively. To further investigate the underlying mechanisms, the effects of melatonin on cells transfected Nrf2 short hairpin RNA (shRNA) and the PI3K / GSK-3β signaling pathway were evaluated.

RESULTS

Treatment with melatonin upregulated Nrf2 expression, inhibited LPS-induced cell morphological change, reversed the expressions of EMT-related proteins, and reduced reactive oxygen species (ROS) production in A549 cells, as well as the levels of malondialdehyde (MDA) and anti-oxidative enzymes. Yet, the effects of melatonin were almost completely abolished in cells transfected Nrf2 shRNA. Furthermore, the data demonstrated that melatonin could activate the PI3K/AKT signaling pathway, resulting in phosphorylation of GSK-3β (Ser9) and upregulation of the Nrf2 protein in A549 cells, which ultimately attenuated LPS-induced EMT.

CONCLUSION

The present study is the first to demonstrate that melatonin can protect human alveolar epithelial cells against oxidative stress by effectively inhibiting LPS-induced EMT, which was mostly dependent on upregulation of the Nrf2 pathway via the PI3K/GSK-3β axis. Further studies are warranted to investigate the role of melatonin for the treatment of oxidative stress-associated diseases, as well as pulmonary fibrosis after ALI.

ACE-2 expression in the small airway epithelia of smokers and COPD patients: implications for COVID-19

Smokers and those with COPD have increased airway expression of ACE-2, which is the entry receptor for the COVID-19 virus. This may explain the increased risk of severe COVID-19 in these subpopulations and highlight the importance of smoking cessation. https://bit.ly/3bC29es

ACE-2 expression in the small airway epithelia of smokers and COPD patients: implications for COVID-19

The World Health Organization (WHO) has declared coronavirus disease 2019 (COVID-19) a pandemic [1]. COVID-19 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 displays symptoms ranging from mild to severe (pneumonia) that can lead to death in some individuals [2–4]. As of 18 April 2020, there have been 2 280 945 cases of COVID-19 worldwide and 156 354 deaths [5]. SARS-CoV-2 uses the angiotensin-converting enzyme II (ACE-2) as the cellular entry receptor [6]. While the virus can infect individuals of any age, to date, most of the severe cases have been described in those >55 years of age and with significant comorbidities, such as COPD [7]. Here, we determined whether patients with COPD have increased expression of ACE-2 in bronchial epithelial cells in the lower respiratory tract.

Smokers and those with COPD have increased airway expression of ACE-2, which is the entry receptor for the COVID-19 virus. This may explain the increased risk of severe COVID-19 in these subpopulations and highlight the importance of smoking cessation. https://bit.ly/3bC29es

F0F1 ATP synthase regulates extracellular calcium influx in human neutrophils by interacting with Cav2.3 and modulates neutrophil accumulation in the lipopolysaccharide-challenged lung

BACKGROUND

Neutrophils form the first line of innate host defense against invading microorganisms. We previously showed that F0F1 ATP synthase (F-ATPase), which is widely known as mitochondrial respiratory chain complex V, is expressed in the plasma membrane of human neutrophils and is involved in regulating cell migration. Whether F-ATPase performs cellular functions through other pathways remains unknown.

METHODS

Blue native polyacrylamide gel electrophoresis followed by nano-ESI-LC MS/MS identification and bioinformatic analysis were used to identify protein complexes containing F-ATPase. Then, the identified protein complexes containing F-ATPase were verified by immunoblotting, immunofluorescence colocalization, immunoprecipitation, real-time RT-PCR and agarose gel electrophoresis. Immunoblotting, flow cytometry and a LPS-induced mouse lung injury model were used to assess the effects of the F-ATPase-containing protein complex in vitro and in vivo.

RESULTS

We found that the voltage-gated calcium channel (VGCC) α2δ-1 subunit is a binding partner of cell surface F-ATPase in human neutrophils. Further investigation found that the physical connection between the two proteins may exist between the F1 part (α and β subunits) of F-ATPase and the α2 part of VGCC α2δ-1. Real-time RT-PCR and PCR analyses showed that Cav2.3 (R-type) is the primary type of VGCC expressed in human neutrophils. Research on the F-ATPase/Cav2.3 functional complex indicated that it can regulate extracellular Ca2+ influx, thereby modulating ERK1/2 phosphorylation and reactive oxygen species production, which are typical features of neutrophil activation. In addition, the inhibition of F-ATPase can reduce neutrophil accumulation in the lungs of mice that were intratracheally instilled with lipopolysaccharide, suggesting that the inhibition of F-ATPase may prevent neutrophilic inflammation-induced tissue damage.

CONCLUSIONS

In this study, we identified a mechanism by which neutrophil activity is modulated, with simultaneous regulation of neutrophil-mediated pulmonary damage. These results show that surface F-ATPase of neutrophils is a potential innate immune therapeutic target.

Expression of sphingosine kinase 1 and sphingosine 1-phosphate receptor 3 in malaria-associated acute lung injury/acute respiratory distress syndrome in a mouse model

This study aimed to investigate the expression of sphingosine kinase 1 (SphK-1) and sphingosine 1-phosphate receptor 3 (S1PR-3) in a mouse model of malaria-associated acute lung injury/acute respiratory distress syndrome (ALI/ARDS). DBA/2 mice were infected with Plasmodium berghei ANKA to generate an experimental model of malaria-associated ALI/ARDS. The infected mice were divided into 2 groups based on the histopathological study of lung tissues: those with and those without ALI/ARDS. The expression of the SphK-1 and S1PR-3 proteins in the lung tissues was investigated using immunohistochemical staining and Western blot analysis. In addition, the S1P level was quantified in plasma and lung tissues using an enzyme-linked immunosorbent assay (ELISA). The results demonstrated that the cellular expression of the SphK-1 and S1PR-3 proteins was significantly upregulated in endothelial cells, alveolar epithelial cells and alveolar macrophages in the lung tissues of malaria-infected mice with ALI/ARDS compared with those in the control groups. The increased expression of the SphK-1 and S1PR-3 proteins was confirmed using Western blot analysis. The concentration of S1P in plasma and lung tissues was significantly decreased in malaria-infected mice with ALI/ARDS compared with non-ALI/ARDS and control mice. Furthermore, increased expression of the SphK-1 and S1PR-3 proteins significantly correlated with lung injury scores and S1P concentrations in malaria-infected mice with ALI/ARDS. These findings highlight increased expression of SphK-1 and S1PR-3 in the lung tissues of malaria-infected mice with ALI/ARDS.

Delivery room interventions to prevent bronchopulmonary dysplasia in preterm infants: a protocol for a systematic review and network meta-analysis

INTRODUCTION

As gestational age decreases, incidence of bronchopulmonary dysplasia (BPD) and chronic lung disease increases. There are many interventions used in the delivery room to prevent acute lung injury and consequently BPD in these patients. The availability of different treatment options often poses a practical challenge to the practicing neonatologist when it comes to making an evidence-based choice as the multitude of pairwise systematic reviews including Cochrane reviews that are currently available only provide a narrow perspective through head-to-head comparisons.

METHODS AND ANALYSIS

We will conduct a systematic review of all randomised controlled trials evaluating delivery room interventions within the first golden hour after birth for prevention of BPD. The primary outcome includes BPD. Secondary outcomes include death at 36 weeks of postmenstrual age or before discharge; severe intraventricular haemorrhage (grade 3 or 4 based on the Papile criteria); any air leak syndromes (including pneumothorax or pulmonary interstitial emphysema); retinopathy of prematurity (any stage) and neurodevelopmental impairment at 18-24 months. We will search from their inception to August 2018, the following databases: Medline, EMBASE and Cochrane Central Register of Controlled Trials as well as grey literature resources. Two reviewers will independently screen titles and abstracts, review full texts, extract information and assess the risk of bias and the confidence in the estimate (with Grading of Recommendations Assessment, Development and Evaluation approach). This review will use Bayesian network meta-analysis approach which allows the comparison of the multiple delivery room interventions for prevention of BPD. We will perform a Bayesian network meta-analysis to combine the pooled direct and indirect treatment effect estimates for each outcome, effectiveness and safety of delivery room interventions for prevention of BPD.

ETHICS AND DISSEMINATION

The proposed protocol is a network meta-analysis, which has been registered on PROSPERO International prospective register of systematic reviews (CRD42018078648). The results will provide an evidence-based guide to choosing the right sequence of early postnatal interventions that will be associated with the least likelihood of inducing lung injury and BPD in preterm infants. Furthermore, we will identify knowledge gaps and will encourage further research for other therapeutic options. Therefore, its results will be disseminated through peer-reviewed publications and conference presentations. Due to the nature of the design, no ethics approval is necessary.

Gas6/Axl signaling attenuates alveolar inflammation in ischemia-reperfusion-induced acute lung injury by up-regulating SOCS3-mediated pathway

Background

Axl is a cell surface receptor tyrosine kinase, and activation of the Axl attenuates inflammation induced by various stimuli. Growth arrest-specific 6 (Gas6) has high affinity for Axl receptor. The role of Gas6/Axl signaling in ischemia-reperfusion-induced acute lung injury (IR-ALI) has not been explored previously. We hypothesized that Gas6/Axl signaling regulates IR-induced alveolar inflammation via a pathway mediated by suppressor of cytokine signaling 3 (SOCS3).

Methods

IR-ALI was induced by producing 30 min of ischemia followed by 90 min of reperfusion in situ in an isolated and perfused rat lung model. The rats were randomly allotted to a control group and IR groups, which were treated with three different doses of Gas6. Mouse alveolar epithelium MLE-12 cells were cultured in control and hypoxia-reoxygenation (HR) conditions with or without Gas6 and Axl inhibitor R428 pretreatment.

Results

We found that Gas6 attenuated IR-induced lung edema, the production of proinflammatory cytokines in perfusates, and the severity of ALI ex vivo. IR down-regulated SOCS3 expression and up-regulated NF-κB, and Gas6 restored this process. In the model of MLE-12 cells with HR, Gas6 suppressed the activation of TRAF6 and NF-κB by up-regulating SOCS3. Axl expression of alveolar epithelium was suppressed in IR-ALI but Gas6 restored phosphorylation of Axl. The anti-inflammatory effect of Gas6 was antagonized by R428, which highlighted that phosphorylation of Axl mediated the protective role of Gas6 in IR-ALI.

Conclusions

Gas6 up-regulates phosphorylation of Axl on alveolar epithelium in IR-ALI. The Gas6/Axl signaling activates the SOCS3-mediated pathway and attenuates IR-related inflammation and injury.

Treatment with 3,4-dihydroxyphenylethyl alcohol glycoside ameliorates sepsis-induced ALI in mice by reducing inflammation and regulating M1 polarization

The bioactive phenylethanoid 3,4-dihydroxyphenylethyl alcohol glycoside (DAG) is a component isolated from Sargentodoxa cuneata. The effects of DAG on acute lung injury (ALI) are largely unknown. Here, the effects of DAG on sepsis-induced ALI were investigated, and the related mechanisms were explored. Male C57BL/6 mice were used to establish a sepsis-induced ALI model. Levels of inflammatory cytokines were determined using real-time quantitative reverse transcription PCRs (qRT-PCR) and enzyme-linked immunosorbent assays (ELISAs). Pathological changes in the lung tissues were evaluated using haematoxylin and eosin (HE) staining. Mouse survival was quantified, and macrophage polarization was analyzed using flow cytometry. Our results showed that, in septic mice, pretreatment with DAG significantly improved survival, reduced histological damage in the lung, and suppressed the inflammatory response by inhibiting the activation of the NF-κB, STAT3, and p38 MAPK signaling pathways. Moreover, DAG treatment reduced the percentage of M1 macrophages in the bronchoalveolar lavage fluid (BALF) and spleen. In addition, DAG treatment decreased the production of pro-inflammatory cytokines and suppressed the activation of the NF-κB, STAT3, and p38 MAPK signaling pathways in LPS-induced MH-S cells. DAG treatment also reduced the relative abundances of M1 macrophages and M1 macrophage markers by suppressing the activation of the Notch1 signaling pathway. Thus, our results provided new insights for the development of drugs to treat ALI.

pH-Responsive Nanoparticles Targeted to Lungs for Improved Therapy of Acute Lung Inflammation/Injury

Dysregulated vascular inflammation is the underlying cause of acute lung inflammation/injury (ALI). Bacterial infections and trauma cause ALI that may rapidly lead to acute respiratory distress syndrome (ARDS). There are no pharmacological therapies available to patients with ALI/ARDS, partially as drugs cannot specifically target the lungs. Herein, we developed a stimuli-responsive nanoparticle (NP) to target inflammatory lungs for ALI therapies. The NP is composed of a sharp acid-sensitive segment poly(β-amino esters) as a core for drug loading and controlled release and a polyethylene glycol-biotin on the particle surface available for bioconjugation, enabling lung targeting and extended circulation. The studies on dissipative particle dynamics simulation and characteristics of NPs suggest that anti-ICAM-1 antibodies can be coated to the particle surface and this coating is required to enhance lung targeting of NPs. A model drug of anti-inflammatory agent TPCA-1 is encapsulated in NPs with a high drug-loading content at 24% (w/w). In the mouse ALI model, our TPCA-1-loaded NPs coated with anti-ICAM-1 can target inflamed lungs after intravenous injection, followed by drug release triggered by the acid environment, thus mitigating lung inflammation and injury. Our studies reveal the rational design of nanotherapeutics for improved therapy of ALI, which may be applied to treating a wide range of vascular inflammation.

Nrf2 Activation Induced by Sirt1 Ameliorates Acute Lung Injury After Intestinal Ischemia/Reperfusion Through NOX4-Mediated Gene Regulation

BACKGROUND/AIMS

Nuclear erythroid 2-related factor-2 (Nrf2) is a major stress-response transcription factor that has been implicated in regulating ischemic angiogenesis. We investigated the effects of Nrf2 in regulating revascularization and modulating acute lung injury.

METHODS

The expression of Nrf2 and sirtuin1 (Sirt1) was assessed in lung tissue by western blotting and immunofluorescence staining after intestinal ischemia/reperfusion (IIR) in Nrf2-/- and wild-type (WT) mice. The involvement of Nrf2 in angiogenesis, cell viability, and migration was investigated in human pulmonary microvascular endothelial cells (PMVECs). Additionally, the influence of Nrf2 expression on NOX pathway activation was measured in PMVECs after oxygen-glucose deprivation/reoxygenation.

RESULTS

We found activation and nuclear accumulation of Nrf2 in lung tissue after IIR. Compared to IIR in WT mice, IIR in Nrf2-/- mice significantly enhanced leukocyte infiltration and collagen deposit, and inhibited endothelial cell marker CD31 expression. Nrf2 upregulation and translocation into the nucleus stimulated by Sirt1 overexpression exhibited remission of histopathologic changes and enhanced CD31 expression. Nrf2 knockdown repressed non-phagocytic cell oxidase 4 (NOX4), hypoxia-inducible factor (HIF-1α) and vascular endothelial growth factor (VEGF) expression after IIR. Nrf2 upregulation by Sirt1 enhances NOX4, HIF-1α and VEGF expression after IIR in WT mice. Furthermore, Nrf2 knockdown suppressed cell viability, capillary tube formation and cell migration in PMVECs after oxygen-glucose deprivation/reoxygenation and also inhibited NOX4, HIF-1 and VEGF expression. Moreover, NOX4 knockdown in PMVECs decreased the levels of VEGF, HIF-1α and angiogenesis.

CONCLUSION

Nrf2 stimulation by Sirt1 plays an important role in sustaining angiogenic potential through NOX4-mediated gene regulation.

Diagnostic indicator of acute lung injury for pediatric critically ill patients at a tertiary pediatric hospital

Early identification of acute lung injury (ALI) in pediatric patients at risk of mortality is important for improving outcome.Assessment of soluble form of receptor for advanced glycation end products (sRAGE) as a valid biomarker for diagnosis of ALI among critically ill, pediatric patients in addition to correlating levels of sRAGE and different outcomes of those patients.A Hospital-based case-control study was conducted in pediatric intensive care units (PICUs) at Cairo University Hospital, along a period of 6 months. Total of 68 pediatric patients following inclusion criteria were classified into: patients with ALI; with both ALI and sepsis; with sepsis and control patients. They were prospectively followed and their laboratory and immunological workup (at days 1 and 9) was done to measure serum sRAGE levels and detect (sRAGE) genotypes.The age of the included children ranged from 8 to 84 months. Plasma level of sRAGE was significantly higher in plasma from patients with ALI regardless of associated sepsis. Plasma sRAGE levels were positively correlated with lung injury score. When assessing sRAGE genotypes, TA and TT genotypes were significant in most of the ALI with and without sepsis patients.Monitoring levels of sRAGE and genotypes can significantly affect the survival of ALI children.

Nephrogenic acute respiratory distress syndrome: A narrative review on pathophysiology and treatment

The kidneys have a close functional relationship with other organs especially the lungs. This connection makes the kidney and the lungs as the most organs involved in the multi-organ failure syndrome. The combination of acute lung injury (ALI) and renal failure results a great clinical significance of 80% mortality rate. Acute kidney injury (AKI) leads to an increase in circulating cytokines, chemokines, activated innate immune cells and diffuse of these agents to other organs such as the lungs. These factors initiate pathological cascade that ultimately leads to ALI and acute respiratory distress syndrome (ARDS). We comprehensively searched the English medical literature focusing on AKI, ALI, organs cross talk, renal failure, multi organ failure and ARDS using the databases of PubMed, Embase, Scopus and directory of open access journals. In this narrative review, we summarized the pathophysiology and treatment of respiratory distress syndrome following AKI. This review promotes knowledge of the link between kidney and lung with mechanisms, diagnostic biomarkers, and treatment involved ARDS induced by AKI.

Effects of penehyclidine hydrochloride on severe acute pancreatitis-associated acute lung injury in rats

Penehyclidine hydrochloride (PHC) is a selective M₁ and M₃ receptor antagonist. This study was designed to investigate the effect of PHC on acute lung injury (ALI) induced by severe acute pancreatitis (SAP) and the expression of hypoxia-inducible factor-1α (HIF-1α) in rats. A total of 45 healthy adult male SD rats were randomly divided into 3 groups: an S group, sham operation; an ALI group, pancreatitis-associated acute lung injury (PALI); and a P group, PALI treated with PHC. Rats from the ALI and P groups were used to establish a model of acute lung injury associated with SAP by retrograde injection of 4% sodium taurocholate into the biliopancreatic duct. Rats in the P group, reflecting acute lung injury caused by SAP, were treated with PHC immediately following SAP. Rats in the S and ALI groups were injected with the same amount of 0.9% sodium chloride solution. After modeling, the rats were sacrificed at 12h. The wet/dry weight (W/D) ratios of lung tissue were calculated. Pathological changes in pancreatic and lung tissues were scored. The expression levels of TLR4 and NF-κB p65 in lung tissue were detected by Western blot. RT-PCR was used to detect HIF-1α mRNA in lung tissue. The HIF-1α, IL-1β, and IL-6 expression levels in lung tissues and serum amylase levels were detected by ELISA. The results showed extensive infiltration of neutrophils, alveolar hemorrhage and necrosis and fat necrosis in the pancreatic tissue of rats in the PALI and P groups. Their pancreatic tissue injury scores were significantly higher than the score of the S group (P<0.01). However, no statistically significant difference was observed in the serum amylase levels of the P and ALI groups (P>0.05). The W/D ratios of lung tissue in the ALI and P group rats were significantly higher than those in the S group (P<0.05). Compared with those of the ALI group rats, the lung tissue pathological changes of the P group were significantly improved, and the lung W/D value was significantly lower than that of the ALI group (P<0.05). Compared with those of the S group, the TLR4, NF-κB p65, HIF-1α mRNA, and HIF-1α expression levels in the lung tissue of the ALI and P groups were significantly higher (P<0.01), and the TLR4, NF-κB p65, HIF-1α mRNA, HIF-1α, IL-1β and IL-6 expression levels in the P group were significantly lower than those in the ALI group (P<0.05). The current work indicates that PHC could not alleviate the damage to pancreatic tissue caused by SAP. However, PHC did suppress HIF-1α, IL-1β and IL-6 expression levels and reduced the acute lung injury induced by SAP in rats, which might depend on suppression of the expression of inflammatory factors, such as HIF-1α.

Plasminogen Activator Inhibitor-1 Is Critical in Alcohol-Enhanced Acute Lung Injury in Mice

Chronic alcohol exposure is a clinically important risk factor for the development of acute respiratory distress syndrome, the most severe form of acute lung injury (ALI). However, the mechanisms by which alcohol sensitizes the lung to development of this disease are poorly understood. We determined the role of the antifibrinolytic protein plasminogen activator inhibitor-1 (PAI-1) in alcohol enhancement of experimental endotoxin-induced ALI. Wild-type, PAI-1-/-, and integrin β3-/- mice were fed ethanol-containing Lieber-DeCarli liquid or a control diet for 6 weeks, followed by systemic LPS challenge. LPS administration triggered coagulation cascade activation as evidenced by increased plasma thrombin-antithrombin levels and pulmonary fibrin deposition. Ethanol-exposed animals showed enhanced PAI-1 expression and pulmonary fibrin deposition with coincident exaggeration of pulmonary inflammatory edematous injury. PAI-1 deficiency markedly reduced pulmonary fibrin deposition and greatly reduced inflammation and injury without impacting upstream coagulation. Interestingly, pulmonary platelet accumulation was effectively abolished by PAI-1 deficiency in ethanol/LPS-challenged mice. Moreover, mice lacking integrin αIIBβ3, the primary platelet receptor for fibrinogen, displayed a dramatic reduction in early inflammatory changes after ethanol/LPS challenge. These results indicate that the mechanism whereby alcohol exaggerates LPS-induced lung injury requires PAI-1-mediated pulmonary fibrin accumulation, and suggest a novel mechanism whereby alcohol contributes to inflammatory ALI by enhancing fibrinogen-platelet engagement.

Gadolinium chloride ameliorates acute lung injury associated with severe acute pancreatitis in rats by regulating CYLD/NF-κB signaling

The present study was embarked on an investigation of the mechanisms behind the effects of Gadolinium chloride (GdCl₃) on lung injury associated with severe acute pancreatitis (SAP) in rats. Rats were randomly distributed into three groups: sham operation group (SO), SAP group and SAP treated with GdCl₃ group (SAP + GdCl₃). Retrograde injection of 5% sodium taurocholate into the biliopancreatic duct was adopted to induce SAP. Lung tissue specimens were harvested for histological study, wet-to-dry weight ratio calculation and myeloperoxidase examination. Meanwhile, bronchoalveolar lavage fluid was analyzed for TNF-α and IL-1β activity and proteins content. Then the apoptosis ratio of alveolar macrophages (AMs) was detected. NF-κB activation and cylindromatosis (CYLD) expression in AMs were measured respectively. Results showed that GdCl₃ treatment notably ameliorated lung injury induced by SAP, and simultaneously, the apoptosis ratio of AMs was significantly promoted. The NF-κB activation was obviously inhibited when CYLD expression was markedly up-regulated in AMs of SAP + GdCl₃. Negative correlation was analyzed between CYLD and NF-κB in both SAP and SAP + GdCl₃. These data demonstrate that GdCl₃ ameliorates lung injury secondary to SAP in rats mainly by up-regulating CYLD expression and inhibiting NF-κB activation in AMs, which may play a vital role in lung injury.

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.

Effects of pressure support and pressure-controlled ventilation on lung damage in a model of mild extrapulmonary acute lung injury with intra-abdominal hypertension

Intra-abdominal hypertension (IAH) may co-occur with the acute respiratory distress syndrome (ARDS), with significant impact on morbidity and mortality. Lung-protective controlled mechanical ventilation with low tidal volume and positive end-expiratory pressure (PEEP) has been recommended in ARDS. However, mechanical ventilation with spontaneous breathing activity may be beneficial to lung function and reduce lung damage in mild ARDS. We hypothesized that preserving spontaneous breathing activity during pressure support ventilation (PSV) would improve respiratory function and minimize ventilator-induced lung injury (VILI) compared to pressure-controlled ventilation (PCV) in mild extrapulmonary acute lung injury (ALI) with IAH. Thirty Wistar rats (334±55g) received Escherichia coli lipopolysaccharide intraperitoneally (1000μg) to induce mild extrapulmonary ALI. After 24h, animals were anesthetized and randomized to receive PCV or PSV. They were then further randomized into subgroups without or with IAH (15 mmHg) and ventilated with PCV or PSV (PEEP = 5cmH₂O, driving pressure adjusted to achieve tidal volume = 6mL/kg) for 1h. Six of the 30 rats were used for molecular biology analysis and were not mechanically ventilated. The main outcome was the effect of PCV versus PSV on mRNA expression of interleukin (IL)-6 in lung tissue. Regardless of whether IAH was present, PSV resulted in lower mean airway pressure (with no differences in peak airway or peak and mean transpulmonary pressures) and less mRNA expression of biomarkers associated with lung inflammation (IL-6) and fibrogenesis (type III procollagen) than PCV. In the presence of IAH, PSV improved oxygenation; decreased alveolar collapse, interstitial edema, and diffuse alveolar damage; and increased expression of surfactant protein B as compared to PCV. In this experimental model of mild extrapulmonary ALI associated with IAH, PSV compared to PCV improved lung function and morphology and reduced type 2 epithelial cell damage.

[Unusual histopathological picture of acute lung injury in different stages of resorption with predominance of organizing pneumonia in a young man with influenza A (H1N1)]

In this case report the authors describe histomorphological findings of acute lung injury with laboratory-confirmed influenza type A(H1N1) pneumonia leading to the death of a 30 year-old unvaccinated man after 27 days of hospitalisation. Histologically all three types of acute lung injuries were unusually present (diffuse alveolar damage, acute interstitial pneumonia, organizing pneumonia) in different phases of resorption and reparation with transition to extensive fibrosis.

Abdominal paracentesis drainage protects rats against severe acute pancreatitis-associated lung injury by reducing the mobilization of intestinal XDH/XOD

Our previous study showed that abdominal paracentesis drainage (APD) benefits patients with severe acute pancreatitis (SAP) by delaying or avoiding multiple organ failure. However, the role of APD treatment in SAP-associated lung injury (PALI) remains unclear. Therefore, we investigated the impact of APD on PALI in rats to explore the mechanisms underlying its potential treatment benefits. A drainage tube was inserted into the right lower quadrant of rats immediately after SAP induction via the retrograde infusion of 5% sodium taurocholate into the biliopancreatic duct. Mortality rates, histological scores, wet-to-dry weight (W/D) ratios, inflammatory infiltration and oxidative stress in lung tissues were then examined. Xanthine dehydrogenase (XDH) and xanthine oxidase (XOD) activities in the sera, intestines and lungs were assessed, as was P-selectin expression. APD treatment significantly decreased pathological damage scores, oxidative stress and neutrophil infiltration in lung tissues, indicating that APD has protective effects against PALI in rats. Moreover, APD decreased the levels of serum α-amylase and trypsin and resulted in a significant decrease in XDH mobilization from the intestines, which suppressed P-selectin expression in lung tissues following SAP induction. APD treatment exerts a significant protective effect against lung injury secondary to SAP by reducing the mobilization of intestinal XDH or XOD (XDH/XOD) and the expression of P-selectin in the lungs. These findings provide novel insights into the mechanisms underlying the effectiveness of APD in patients with SAP.

Early blood purification therapy of severe acute pancreatitis complicated by acute lung injury

OBJECTIVE

Severe acute pancreatitis (SAP) can often be complicated by acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), leading to increased mortality. Early blood purification clears inflammatory cytokines and promotes immune function recovery. Here we evaluated the usefulness of this therapy in SAP complicated by ALI.

PATIENTS AND METHODS

32 patients received routine treatment (control group), whereas other 32 patients received routine treatment and early blood purification therapy (study group). We evaluated respiratory indexes (PaO2, PaO2/FiO2, alveolar-arterial oxygen difference, intrapulmonary arteriovenous shunt percentage, and respiratory rate), blood biochemical (creatinine, blood urea nitrogen, alanine aminotransferase, and lactate levels) and inflammatory (CRP, IL-10, TNF-α, and IL-10/TNF-α ratio) markers, and prognostic outcomes (multiple organ dysfunction syndrome [MODS] and APACHE II scores) before and 72 hours after the treatment. We also documented mechanical ventilation use, occurrence of MODS and ARDS, and mortality rates.

RESULTS

There were no deaths. Mechanical ventilation was used in a similar percentage of patients in either group. Treatment in study group led to a faster and better recovery of respiratory indexes, and less pronounced changes in the levels of blood urea nitrogen and alanine aminotransferase. Inflammatory markers also normalized better in the study group. Furthermore, MODS and APACHE II scores decreased to a greater extent in the study group, paralleled by a lower occurrence of MPDS and ARDS.

CONCLUSIONS

Early blood purification therapy improves respiratory function and inflammatory markers in patients with SAP complicated by ALI, and decreases the occurrence of MODS and ARDS.

Effect of Thoracentesis on Intubated Patients with Acute Lung Injury

Pleural effusions occur frequently in mechanically ventilated patients, but no consensus exists regarding the clinical benefit of effusion drainage. We sought to determine the impact of thoracentesis on gas exchange in patients with differing severities of acute lung injury (ALI). A retrospective analysis was conducted on therapeutic thoracenteses performed on intubated patients in an adult surgical intensive care unit of a tertiary center. Effusions judged by ultrasound to be 400 mL or larger were drained. Subjects were divided into groups based on their initial P:F ratios: normal >300, ALI 200 to 300, and acute respiratory distress syndrome (ARDS) <200. Baseline characteristics, physiologic variables, arterial blood gases, and ventilator settings before and after the intervention were analyzed. The primary end point was the change in measures of oxygenation. Significant improvements in P:F ratios (mean ± SD) were seen only in patients with ARDS (50.4 ± 38.5, P = 0.001) and ALI (90.6 ± 161.7, P = 0.022). Statistically significant improvement was observed in the pO2 (31.1, P = 0.005) and O2 saturation (4.1, P < 0.001) of the ARDS group. The volume of effusion removed did not correlate with changes in individual patient's oxygenation. These data support the role of therapeutic thoracentesis for intubated patients with abnormal P:F ratios.

Ecto-5'-nucleotidase CD73 modulates the innate immune response to influenza infection but is not required for development of influenza-induced acute lung injury

Extracellular nucleotides and nucleosides are important signaling molecules in the lung. Nucleotide and nucleoside concentrations in alveolar lining fluid are controlled by a complex network of surface ectonucleotidases. Previously, we demonstrated that influenza A/WSN/33 (H1N1) virus resulted in increased levels of the nucleotide ATP and the nucleoside adenosine in bronchoalveolar lavage fluid (BALF) of wild-type (WT) C57BL/6 mice. Influenza-induced acute lung injury (ALI) was highly attenuated in A1-adenosine receptor-knockout mice. Because AMP hydrolysis by the ecto-5'-nucleotidase (CD73) plays a central role in and is rate-limiting for generation of adenosine in the normal lung, we hypothesized that ALI would be attenuated in C57BL/6-congenic CD73-knockout (CD73-KO) mice. Infection-induced hypoxemia, bradycardia, viral replication, and bronchoconstriction were moderately increased in CD73-KO mice relative to WT controls. However, postinfection weight loss, pulmonary edema, and parenchymal dysfunction were not altered. Treatment of WT mice with the CD73 inhibitor 5'-(α,β-methylene) diphosphate (APCP) also had no effect on infection-induced pulmonary edema but modestly attenuated hypoxemia. BALF from CD73-KO and APCP-treated WT mice contained more IL-6 and CXCL-10/IFN-γ-induced protein 10, less CXCL-1/keratinocyte chemoattractant, and fewer neutrophils than BALF from untreated WT controls. BALF from APCP-treated WT mice also contained fewer alveolar macrophages and more transforming growth factor-β than BALF from untreated WT mice. These results indicate that CD73 is not necessary for development of ALI following influenza A virus infection and suggest that tissue-nonspecific alkaline phosphatase may be responsible for increased adenosine generation in the infected lung. However, they do suggest that CD73 has a previously unrecognized immunomodulatory role in influenza.

Mesenchymal stem cells reverse trauma and hemorrhagic shock-induced bone marrow dysfunction

BACKGROUND

Lung contusion (LC) followed by hemorrhagic shock (HS) causes persistent bone marrow (BM) dysfunction lasting up to 7 d after injury. Mesenchymal stem cells (MSCs) are multipotent cells that can hasten healing and exert protective immunomodulatory effects. We hypothesize that MSCs can attenuate BM dysfunction after combined LCHS.

MATERIALS AND METHODS

Male Sprague-Dawley rats (n = 5-6 per group) underwent LC plus 45 min of HS (mean arterial pressure of 30-35). Allogeneic MSCs (5 × 10(6) cells) were injected intravenously after resuscitation. At 7 d, BM was analyzed for cellularity and growth of hematopoietic progenitor cell (HPC) colonies (colony-forming unit-erythroid; burst-forming unit-erythroid; and colony-forming unit-granulocyte, erythrocyte, monocyte, megakaryocyte). Flow cytometry measured %HPCs in peripheral blood; plasma granulocyte colony-stimulating factor (G-CSF) levels were measured via enzyme-linked immunosorbent assay. Data were analyzed by one-way analysis of variance followed by the Tukey multiple comparison test.

RESULTS

As previously shown, at 7 d, LCHS resulted in 22%, 30%, and 24% decreases in colony-forming unit-granulocyte, erythrocyte, monocyte, megakaryocyte, burst-forming unit-erythroid, and colony-forming unit-erythroid colony growth, respectively, versus naive. Treatment with MSCs returned all BM parameters to naive levels. There was no difference in %HPCs in peripheral blood between groups; however, G-CSF remained increased up to 7 d after LCHS. MSCs returned G-CSF to naive levels. Plasma from animals receiving MSCs was not suppressive to the BM.

CONCLUSIONS

One week after injury, the persistent BM dysfunction observed in animals undergoing LCHS is reversed by treatment with MSCs with an associated return of plasma G-CSF levels to normal. Plasma from animals undergoing LCHS plus MSCs was not suppressive to BM cells in vitro. Treatment with MSCs after injury and shock reverses BM suppression and returns plasma G-CSF levels to normal.

Therapeutic exercise attenuates neutrophilic lung injury and skeletal muscle wasting

Early mobilization of critically ill patients with the acute respiratory distress syndrome (ARDS) has emerged as a therapeutic strategy that improves patient outcomes, such as the duration of mechanical ventilation and muscle strength. Despite the apparent efficacy of early mobility programs, their use in clinical practice is limited outside of specialized centers and clinical trials. To evaluate the mechanisms underlying mobility therapy, we exercised acute lung injury (ALI) mice for 2 days after the instillation of lipopolysaccharides into their lungs. We found that a short duration of moderate intensity exercise in ALI mice attenuated muscle ring finger 1 (MuRF1)-mediated atrophy of the limb and respiratory muscles and improved limb muscle force generation. Exercise also limited the influx of neutrophils into the alveolar space through modulation of a coordinated systemic neutrophil chemokine response. Granulocyte colony-stimulating factor (G-CSF) concentrations were systemically reduced by exercise in ALI mice, and in vivo blockade of the G-CSF receptor recapitulated the lung exercise phenotype in ALI mice. Additionally, plasma G-CSF concentrations in humans with acute respiratory failure (ARF) undergoing early mobility therapy showed greater decrements over time compared to control ARF patients. Together, these data provide a mechanism whereby early mobility therapy attenuates muscle wasting and limits ongoing alveolar neutrophilia through modulation of systemic neutrophil chemokines in lung-injured mice and humans.

Pressure-controlled versus volume-controlled ventilation for acute respiratory failure due to acute lung injury (ALI) or acute respiratory distress syndrome (ARDS)

BACKGROUND

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) account for one-quarter of cases of acute respiratory failure in intensive care units (ICUs). A third to half of patients will die in the ICU, in hospital or during follow-up. Mechanical ventilation of people with ALI/ARDS allows time for the lungs to heal, but ventilation is invasive and can result in lung injury. It is uncertain whether ventilator-related injury would be reduced if pressure delivered by the ventilator with each breath is controlled, or whether the volume of air delivered by each breath is limited.

OBJECTIVES

To compare pressure-controlled ventilation (PCV) versus volume-controlled ventilation (VCV) in adults with ALI/ARDS to determine whether PCV reduces in-hospital mortality and morbidity in intubated and ventilated adults.

SEARCH METHODS

In October 2014, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2014, Isssue 9), MEDLINE (1950 to 1 October 2014), EMBASE (1980 to 1 October 2014), the Latin American Caribbean Health Sciences Literature (LILACS) (1994 to 1 October 2014) and Science Citation Index-Expanded (SCI-EXPANDED) at the Institute for Scientific Information (ISI) Web of Science (1990 to 1 October 2014), as well as regional databases, clinical trials registries, conference proceedings and reference lists.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and quasi-RCTs (irrespective of language or publication status) of adults with a diagnosis of acute respiratory failure or acute on chronic respiratory failure and fulfilling the criteria for ALI/ARDS as defined by the American-European Consensus Conference who were admitted to an ICU for invasive mechanical ventilation, comparing pressure-controlled or pressure-controlled inverse-ratio ventilation, or an equivalent pressure-controlled mode (PCV), versus volume-controlled ventilation, or an equivalent volume-controlled mode (VCV).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened and selected trials, assessed risk of bias and extracted data. We sought clarification from trial authors when needed. We pooled risk ratios (RRs) for dichotomous data and mean differences (MDs) for continuous data with their 95% confidence intervals (CIs) using a random-effects model. We assessed overall evidence quality using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach.

MAIN RESULTS

We included three RCTs that randomly assigned a total of 1089 participants recruited from 43 ICUs in Australia, Canada, Saudi Arabia, Spain and the USA. Risk of bias of the included studies was low. Only data for mortality and barotrauma could be combined in the meta-analysis. We downgraded the quality of evidence for the three mortality outcomes on the basis of serious imprecision around the effect estimates. For mortality in hospital, the RR with PCV compared with VCV was 0.83 (95% CI 0.67 to 1.02; three trials, 1089 participants; moderate-quality evidence), and for mortality in the ICU, the RR with PCV compared with VCV was 0.84 (95% CI 0.71 to 0.99; two trials, 1062 participants; moderate-quality evidence). One study provided no evidence of clear benefit with the ventilatory mode for mortality at 28 days (RR 0.88, 95% CI 0.73 to 1.06; 983 participants; moderate-quality evidence). The difference in effect on barotrauma between PCV and VCV was uncertain as the result of imprecision and different co-interventions used in the studies (RR 1.24, 95% CI 0.87 to 1.77; two trials, 1062 participants; low-quality evidence). Data from one trial with 983 participants for the mean duration of ventilation, and from another trial with 78 participants for the mean number of extrapulmonary organ failures that developed with PCV or VCV, were skewed. None of the trials reported on infection during ventilation or quality of life after discharge.

AUTHORS' CONCLUSIONS

Currently available data from RCTs are insufficient to confirm or refute whether pressure-controlled or volume-controlled ventilation offers any advantage for people with acute respiratory failure due to acute lung injury or acute respiratory distress syndrome. More studies including a larger number of people given PCV and VCV may provide reliable evidence on which more firm conclusions can be based.

Pulmonary histopathologic abnormalities and predictor variables in autopsies of burned pediatric patients

Pulmonary abnormalities occur in 30-80% of fatalities after burn. The objective of our study is to investigate lung pathology in autopsy tissues of pediatric burn patients.

METHODS

Three scientists with pathology training in pediatric burn care reviewed masked autopsy slides of burned children who died after admission to a burn center from 2002 to 2012 (n=43). Autopsy lung tissue was assigned scores for histologic abnormalities in 9 categories, including alveolar and interstitial fibrosis, hyaline membranes, and type II epithelial cell proliferation. Scores were then tested for correlation with age, TBSA burn, number of days between burn and death, time between burn and admission, and the presence of inhalation injury using analyses with linear models.

RESULTS

Type II epithelial cell proliferation was significantly more common in cases with a longer time between burn and admission (p<0.02). Interstitial fibrosis was significantly more severe in cases with longer survival after burn (p<0.01). The scores for protein were significantly higher in cases with longer survival after burn (p<0.03). Enlarged air spaces were significantly more prominent in cases with longer survival after burn (p<0.01), and in cases with the presence of inhalation injury (p<0.01).

CONCLUSIONS

Histological findings associated with diffuse alveolar damage (DAD), which is the pathological correlate of the acute respiratory distress syndrome (ARDS), were seen in approximately 42% of autopsies studied. Protein-rich alveolar edema, which is the abnormality that leads to ARDS, may occur from multiple causes, including inhalation injury.

Safety of research bronchoscopy in critically ill patients

OBJECTIVE

Bronchoscopy and bronchoalveolar lavage (BAL) are common procedures in intensive care units; however, no contemporaneous safety and outcomes data have been reported, particularly for critically ill patients.

DESIGN

This is a retrospective analysis of prospectively collected data from teaching hospital adult intensive care units.

INTERVENTIONS

One hundred mechanically ventilated patients with severe sepsis, septic shock, acute lung injury (ALI), and/or acute respiratory distress syndrome underwent bronchoscopy with unilateral BAL. Data collected included demographics, presence of sepsis or ALI, Pao2 to Fio2 ratio, positive end-expiratory pressure, Acute Physiology and Chronic Health Evaluation score, Sequential Organ Failure Assessment score, and peri- or postprocedural complications.

RESULTS

Men comprised 51% of the patients; 81% of the patients were black, and 15% were white. The mean age was 52 (SD, ±16) years. The mean Acute Physiology and Chronic Health Evaluation score was 22 (±7.5), whereas the median Sequential Organ Failure Assessment score was 9 (interquartile range, 5-12). Ten patients (10%) had complications during or immediately after the procedure. Hypoxemia during or immediately after the BAL was the most common complication. Ninety percent of the complications were related to transient hypoxemia, whereas bradycardia and hypotension each occurred in 1 patient. Age, female sex, and higher positive end-expiratory pressure were associated with complications.

CONCLUSIONS

Bronchoscopy with BAL in critically ill patients with sepsis and ALI is well tolerated with low risk of complications, primarily related to manageable hypoxemia.

H₂S protecting against lung injury following limb ischemia-reperfusion by alleviating inflammation and water transport abnormality in rats

OBJECTIVE

To investigate the effect of H₂S on lower limb ischemia-reperfusion (LIR) induced lung injury and explore the underlying mechanism.

METHODS

Wistar rats were randomly divided into control group, IR group, IR+ Sodium Hydrosulphide (NaHS) group and IR+ DL-propargylglycine (PPG) group. IR group as lung injury model induced by LIR were given 4 h reperfusion following 4 h ischemia of bilateral hindlimbs with rubber bands. NaHS (0.78 mg/kg) as exogenous H₂S donor and PPG (60 mg/kg) which can suppress endogenous H₂S production were administrated before LIR, respectively. The lungs were removed for histologic analysis, the determination of wet-to-dry weight ratios and the measurement of mRNA and protein levels of aquaporin-1 (AQP₁), aquaporin-5 (AQP₅) as indexes of water transport abnormality, and mRNA and protein levels of Toll-like receptor 4 (TLR₄), myeloid differentiation primary-response gene 88 (MyD88) and p-NF-κB as indexes of inflammation.

RESULTS

LIR induced lung injury was accompanied with upregulation of TLR₄-Myd88-NF-κB pathway and downregulation of AQP1/AQP₅. NaHS pre-treatment reduced lung injury with increasing AQP₁/AQP₅ expression and inhibition of TLR₄-Myd88-NF-κB pathway, but PPG adjusted AQP₁/AQP₅ and TLR4 pathway to the opposite side and exacerbated lung injury.

CONCLUSION

Endogenous H₂S, TLR₄-Myd88-NF-κB pathway and AQP₁/AQP₅ were involved in LIR induced lung injury. Increased H₂S would alleviate lung injury and the effect is at least partially depend on the adjustment of TLR₄-Myd88-NF-κB pathway and AQP₁/AQP₅ expression to reduce inflammatory reaction and lessen pulmonary edema.