Activation of PI3K/Akt/HIF-1α Signaling is Involved in Lung Protection of Dexmedetomidine in Patients Undergoing Video-Assisted Thoracoscopic Surgery: A Pilot Study.

BACKGROUND: Lung resection and one lung ventilation (OLV) during video-assisted thoracoscopic surgery (VATS) may lead to acute lung injury. Dexmedetomidine (DEX), a highly selective α2 adrenergic receptor agonist, improves arterial oxygenation in adult patients undergoing thoracic surgery. The aim of this pilot study was to explore possible mechanism related to lung protection of DEX in patients undergoing VATS. PATIENTS AND METHODS: Seventy-four patients scheduled for VATS were enrolled in this study. Three timepoints (before anesthesia induction (T0), 40 min after OLV (T1), and 10 min after two-lung ventilation (T2)) of arterial blood gas were obtained. Meanwhile, lung histopathologic examination, immunohistochemistry analysis (occludin and ZO-1), levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in lung tissue and plasma, and activation of phosphoinositide-3-kinase (PI3K)/AKT/hypoxia-inducible factor (HIF)-1α signaling were detected. Postoperative outcomes including duration of withdrawing the pleural drainage tube, length of hospital stay, hospitalization expenses, and postoperative pulmonary complications (PPCs) were also recorded. RESULTS: Sixty-seven patients were randomly divided into DEX group (group D, n=33) and control group (group N, n=34). DEX improved oxygenation at T1 and T2 (group D vs group N; T1: 191.8 ± 49.8 mmHg vs 159.6 ± 48.1 mmHg, P = 0.009; T2: 406.0 mmHg [392.2-423.7] vs 374.5 mmHg [340.2-378.2], P = 0.001). DEX alleviated the alveolar capillary epithelial structure damage, increased protein expression of ZO-1 and occludin, inhibited elevation of the expression of TNF-α and IL-6 in lung tissue and plasma, and increased protein expression of p-PI3K, p-AKT and HIF-1α. Dex administered had better postoperative outcomes with less risk of PPCs and hospitalization expenses as well as shorter duration of withdrawing the pleural drainage tube and length of hospital stay. CONCLUSION: Activation of PI3K/Akt/HIF-1α signaling might be involved in lung protection of DEX in patients undergoing VATS.

Bone marrow-derived mesenchymal stem cells attenuate pulmonary inflammation and lung damage caused by highly pathogenic avian influenza A/H5N1 virus in BALB/c mice.

BACKGROUND: The highly pathogenic avian influenza A/H5N1 virus is one of the causative agents of acute lung injury (ALI) with high mortality rate. Studies on therapeutic administration of bone marrow-derived mesenchymal stem cells (MSCs) in ALI caused by the viral infection have been limited in number and have shown conflicting results. The aim of the present investigation is to evaluate the therapeutic potential of MSC administration in A/H5N1-caused ALI, using a mouse model. METHODS: MSCs were prepared from the bone marrow of 9 to 12 week-old BALB/c mice. An H5N1 virus of A/turkey/East Java/Av154/2013 was intranasally inoculated into BALB/c mice. On days 2, 4, and 6 after virus inoculation, MSCs were intravenously administered into the mice. To evaluate effects of the treatment, we examined for lung alveolar protein as an indicator for lung injury, PaO2/FiO2 ratio for lung functioning, and lung histopathology. Expressions of NF-κB, RAGE (transmembrane receptor for damage associated molecular patterns), TNFα, IL-1ß, Sftpc (alveolar cell type II marker), and Aqp5+ (alveolar cell type I marker) were examined by immunohistochemistry. In addition, body weight, virus growth in lung and brain, and duration of survival were measured. RESULTS: The administration of MSCs lowered the level of lung damage in the virus-infected mice, as shown by measuring lung alveolar protein, PaO2/FiO2 ratio, and histopathological score. In the MSC-treated group, the expressions of NF-κB, RAGE, TNFα, and IL-1ß were significantly suppressed in comparison with a mock-treated group, while those of Sftpc and Aqp5+ were enhanced. Body weight, virus growth, and survival period were not significantly different between the groups. CONCLUSION: The administration of MSCs prevented further lung injury and inflammation, and enhanced alveolar cell type II and I regeneration, while it did not significantly affect viral proliferation and mouse morbidity and mortality. The results suggested that MSC administration was a promissing strategy for treatment of acute lung injuries caused by the highly pathogenic avian influenza A/H5N1 virus, although further optimization and combination use of anti-viral drugs will be obviously required to achieve the goal of reducing mortality.

Obesity is a risk factor for preoperative hypoxemia in Stanford A acute aortic dissection.

Obese individuals are apt to develop Stanford A acute aortic dissection (AAD) complicated with acute lung injury (ALI), but the mechanism is still not well defined. We aim to investigate whether oxidative stress and inflammatory are involved in the aortic dissection lung injury caused by obesity.Seventy-nine patients were categorized into AAD with obesity group (n = 17) and AAD without obesity group (n = 62) according to body mass index (BMI). Inflammatory reactions including interleukin 1ß (IL-1ß), tumor necrosis factor-α (TNF-α), IL-6, C-reactive protein (CRP) and white blood cell (WBC) count, and oxidative stress including malondialdehyde (MDA), superoxide dismutase were determined using enzyme-linked immunosorbent assays and chemiluminescence. All the patients received ascending aorta replacement combined with total arch replacement and stented elephant trunk. The postoperative complications were recorded.The incidence of preoperative hypoxemia (94.1% vs 35.5%, P < .01) and postoperative ALI (88.2% vs 40.3%, P < .01) in obese patients was significantly higher than that in non-obese patients. Besides, the ICU stay (119.2 ±â€Š59.2 vs 87.8 ±â€Š31.2 h, P < .01) and hospitalization duration (18.8 ±â€Š8.5 vs 14.3 ±â€Š8.1d, P = .048) were increased in the obese patients with AAD. The expression of IL-1ß, TNF-α, IL-6, CRP, and WBC was remarkably increased (P < .01) in obese group compared with non-obese group.Oxidative stress and inflammatory response may be involved in the process of ALI of aortic dissection caused by obesity, which provides new ideas for the treatment of ALI of the aortic dissection.

Effects of nalmefene hydrochloride on TLR4 signaling pathway in rats with lung ischemia-reperfusion injury.

OBJECTIVE: To investigate the effect of nalmefene hydrochloride on TLR4 signaling pathway in rats with lung ischemia-reperfusion injury. MATERIALS AND METHODS: Altogether 64 pure inbred male SD rats were divided into groups A, B, C, and D according to the principle of body weight similarity, with 24 rats in each group. Four groups of rats were respectively twisted on the left testis to establish unilateral testicular torsion rats. Group A was the control group, treated with normal saline, group B was the nalmefene hydrochloride high-dose group, treated with 20 µg/kg of nalmefene hydrochloride, group C was the nalmefene hydrochloride low-dose group, treated with 10 µg/kg of nalmefene hydrochloride, and group D was the sham operation group. Lung tissue was collected 60 h later. Western blotting was used to detect the expression levels of HMGB1, TLR4, CD14, and NF-κB protein, qPCR was used to detect the mRNA expression level, and enzyme-linked immunosorbent assay (ELISA) was used to detect the expression levels of inflammatory factors IL-17, IL-6, and ICAM-1. RESULTS: The expression levels of HMGB1, TLR4, CD14, NF-κB protein, mRNA, IL-17, IL-6, and ICAM-1 in group A were significantly higher than those in groups B, C, and D (p<0.05), while were significantly lower in group D than in groups B and C (p<0.05), and were significantly lower in group B than in group C (p<0.05). CONCLUSIONS: Nalmefene hydrochloride can effectively inhibit the signal pathway of TLR4, and can effectively reduce the injury caused by lung ischemia-reperfusion. The large dose is closely related to the good effect, which is worthy of promotion.

Intrasplenic Transplantation of Cytotoxic T-Lymphocyte Associated Protein 4-Fas Ligand--Modified Hepatic Oval Cells for Acute Liver Injury in Rats.

BACKGROUND: Intrasplenic transplantation of xenogeneic hepatic oval cells (HOCs) may provide metabolic support for acute liver injury. However, xenoreactive lymphocyte-mediated immune response hinders HOCs' survival in the xeno-spleen parenchyma. Cytotoxic T-lymphocyte associated protein 4-Fas ligand (CTLA4.FasL), a fusion product integrating 2 inhibitory elements against lymphocytes into 1 molecule, effectively inhibited the proliferation of allogeneic and autoimmune lymphocytes. The purpose of this study was to explore the effect of CTLA4.FasL on the proliferation of xenoreactive lymphocytes and evaluate the therapeutic efficacy of CTLA4.FasL-modified HOC transplantation on acute liver injury in rats. METHODS: The effect of CTLA4.FasL-modified mouse liver epithelial progenitor cells (CTLA4.FasL-LEPCs) on the proliferation of rat lymphocytes in xeno-mixed lymphocyte reaction was investigated. Furthermore, CTLA4.FasL-LEPCs were intrasplenically transplanted in carbon tetrachloride- and partial hepatectomy-treated rats, and the therapeutic effect was evaluated using hematoxylin and eosin staining and alanine aminotransferase and aspartate aminotransferase assays. The hepatocytic differentiation of CTLA4.FasL-LEPCs in xenogeneic spleen was monitored by immunohistochemical staining for albumin. RESULTS: In xeno-mixed lymphocyte reaction, CTLA4.FasL-LEPCs substantially inhibited the rat lymphocytes proliferation. CTLA4.FasL-LEPC transplantation significantly ameliorated liver injury compared with mCherry-modified LEPC and LEPC transplantation, as assessed by hematoxylin and eosin staining, alanine aminotransferase, and aspartate aminotransferase assays. Albumin positive cells appeared only in CTLA4.FasL-LEPCs group, but not in the mCherry-modified LEPCs group and LEPCs group. CONCLUSIONS: Our results indicate CTLA4.FasL-LEPCs substantially improved liver function and structure in carbon tetrachloride- and partial hepatectomy-induced acute liver injury rats through long-term hepatocytic differentiation.

Inactivating hepatitis C virus in donor lungs using light therapies during normothermic ex vivo lung perfusion.

Availability of organs is a limiting factor for lung transplantation, leading to substantial mortality rates on the wait list. Use of organs from donors with transmissible viral infections, such as hepatitis C virus (HCV), would increase organ donation, but these organs are generally not offered for transplantation due to a high risk of transmission. Here, we develop a method for treatment of HCV-infected human donor lungs that prevents HCV transmission. Physical viral clearance in combination with germicidal light-based therapies during normothermic ex-vivo Lung Perfusion (EVLP), a method for assessment and treatment of injured donor lungs, inactivates HCV virus in a short period of time. Such treatment is shown to be safe using a large animal EVLP-to-lung transplantation model. This strategy of treating viral infection in a donor organ during preservation could significantly increase the availability of organs for transplantation and encourages further clinical development.

Regeneration of the lung alveolus by an evolutionarily conserved epithelial progenitor.

Functional tissue regeneration is required for the restoration of normal organ homeostasis after severe injury. Some organs, such as the intestine, harbour active stem cells throughout homeostasis and regeneration; more quiescent organs, such as the lung, often contain facultative progenitor cells that are recruited after injury to participate in regeneration. Here we show that a Wnt-responsive alveolar epithelial progenitor (AEP) lineage within the alveolar type 2 cell population acts as a major facultative progenitor cell in the distal lung. AEPs are a stable lineage during alveolar homeostasis but expand rapidly to regenerate a large proportion of the alveolar epithelium after acute lung injury. AEPs exhibit a distinct transcriptome, epigenome and functional phenotype and respond specifically to Wnt and Fgf signalling. In contrast to other proposed lung progenitor cells, human AEPs can be directly isolated by expression of the conserved cell surface marker TM4SF1, and act as functional human alveolar epithelial progenitor cells in 3D organoids. Our results identify the AEP lineage as an evolutionarily conserved alveolar progenitor that represents a new target for human lung regeneration strategies.

A Conserved Distal Lung Regenerative Pathway in Acute Lung Injury.

Improved tools have led to a burgeoning understanding of lung regeneration in mice, but it is not yet known how these insights may be relevant to acute lung injury in humans. We report in detail two cases of fulminant idiopathic acute lung injury requiring extracorporeal membrane oxygenation in previously healthy young adults with acute respiratory distress syndrome, one of whom required lung transplantation. Biopsy specimens showed diffuse alveolar injury with a striking paucity of alveolar epithelial regeneration, rare hyaline membranes, and diffuse contiguous airspace lining by macrophages. This novel constellation was termed diffuse alveolar injury with delayed epithelization. In addition, mirroring data from murine models of lung injury/regeneration, peribronchiolar basaloid pods (previously described as squamous metaplasia) and ciliated bronchiolarization were identified in these patients and in 39% of 57 historical cases with diffuse alveolar damage. These findings demonstrate a common and clinically relevant human disease correlate for murine models of severe acute lung injury. Evidence suggests that peribronchiolar basaloid pods and bronchiolarization are related spatially and temporally and likely represent overlapping sequential stages of the response to severe distal airway injury.

Intratracheal instillation of alveolar type II cells enhances recovery from acute lung injury in rats.

BACKGROUND: Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are characterized by excess production of inflammatory factors. Alveolar type II (ATII) cells help repair damaged lung tissue, rapidly proliferating and differentiating into alveolar type I cells after epithelial cell injury. In ALI, the lack of viable ATII favors progression to more severe lung injury. ATII cells regulate the immune response by synthesizing surfactant and other anti-inflammatory proteins and lipids. Cross-talk between ATII and other cells such as macrophages may also be part of the ATII function. The aim of this study was to test the anti-inflammatory and reparative effects of ATII cells in an experimental model of ALI. METHODS: In this study ATII cells (2.5 × 106 cells/animal) were intratracheally instilled in rats with HCl and lipopolysaccharide (LPS)-induced ALI and in healthy animals to check for side effects. The specific effect of ATII cells was compared with fibroblast transplantation. RESULTS: ATII cell transplantation promoted recovery of lung function, decrease mortality and lung inflammation of the animals with ALI. The primary mechanisms for benefit were paracrine effects of prostaglandin E2 (PGE2) and surfactant protein A (SPA) released from ATII cells that modulate alveolar macrophages to an anti-inflammatory phenotype. To our knowledge, these data are the first to provide evidence that ATII cells secrete PGE2 and SPA, reducing pro-inflammatory macrophage activation and ALI. CONCLUSION: ATII cells and their secreted molecules have shown an ability to resolve ALI, thereby highlighting a potential novel therapeutic target.

Mesenchymal stem cells improves survival in LPS-induced acute lung injury acting through inhibition of NETs formation.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are syndromes of acute hypoxemic respiratory failure resulting from a variety of direct and indirect injuries to the gas exchange parenchyma of the lungs. During the ALI, we have an increase release of proinflammatory cytokines and high reactive oxygen species (ROS) formation. These factors are responsible for the release and activation of neutrophil-derived proteases and the formation of neutrophil extracellular traps (NETs). The excessive increase in the release of NETs cause damage to lung tissue. Recent studies have studies involving the administration of mesenchymal stem cells (MSCs) for the treatment of experimental ALI has shown promising results. In this way, the objective of our study is to evaluate the ability of MSCs, in a lipopolysaccharide (LPS)-induced ALI model, to reduce inflammation, oxidative damage, and consequently decrease the release of NETs. Mice were submitted lung injury induced by intratracheal instillation of LPS and subsequently treated or not with MSCs. Treatment with MSCs was able to modulate pulmonary inflammation, decrease oxidative damage, and reduce the release of NETs. These benefits from treatment are evident when we observe a significant increase in the survival curve in the treated animals. Our results demonstrate that MSCs treatment is effective for the treatment of ALI. For the first time, it is described that MSCs can reduce the formation of NETs and an experimental model of ALI. This finding is directly related to these cells modulate the inflammatory response and oxidative damage in the course of the pathology.

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.

Mesenteric Lymph Duct Ligation Alleviating Lung Injury in Heatstroke.

To explore the roles of mesenteric lymph on lung injury in heatstroke (HS), HS rat model was prepared in a prewarmed incubator. Vascular endothelium injury biomarkers (circulating endothelial cell [CEC] as well as von Willebrand factor [vWF] and thrombomodulin [TM]), proinflammatory factors (tumor necrosis factor-α [TNF-α], interleukin-1ß [IL-1ß], IL-6, and high mobility group box 1), and coagulant markers (activated partial thromboplastin time, prothrombin time, D-Dimer, and platelet count) were tested in HS and HS with mesenteric lymph duct ligation (LDL) rats. In addition, lung histopathology; arterial blood gas; Evans Blue dye (EBD) and protein lung permeability; intralung inflammatory parameters including bronchoalveolar lavage fluid (BALF) TNF-α, IL-1ß, and IL-6 levels; myeloperoxidase (MPO) activity; and vWF immune staining were analyzed. LDL prolonged HS onset time but not HS survival time. LDL significantly attenuated endothelial cell injury for decreased CEC counts as well as plasma vWF and TM concentrations; downregulated systemic inflammation for decreased plasma TNF-α, IL-1ß, IL-6, and high mobility group box 1 levels; and ameliorated coagulant disorders for decreased activated partial thromboplastin time, prothrombin time, and D-Dimer levels as well as increased platelet counts. LDL also significantly reduced acute lung pathological injury; improved lung function indexes including arterial blood PaO2, pH, PaCO2, and lactic acid; decreased BALF TNF-α, IL-1ß, and IL-6 levels and lung MPO activity; improved EBD and protein lung permeability; and inhibited lung vascular endothelium vWF expression. However, all of these parameters were not recovered to the normal states. In summary, LDL developed protection roles systemically and alleviated lung injury in HS rats which indicated that modulating mesenteric lymph flow may have some potential benefits in HS.

Extracorporeal Respiratory Support With a Miniature Integrated Pediatric Pump-Lung Device in an Acute Ovine Respiratory Failure Model.

Respiratory failure is one of the major causes of mortality and morbidity all over the world. Therapeutic options to treat respiratory failure remain limited. The objective of this study was to evaluate the gas transfer performance of a newly developed miniature portable integrated pediatric pump-lung device (PediPL) with small membrane surface for respiratory support in an acute ovine respiratory failure model. The respiratory failure was created in six adult sheep using intravenous anesthesia and reduced mechanical ventilation at 2 breaths/min. The PediPL device was surgically implanted and evaluated for respiratory support in a venovenous configuration between the right atrium and pulmonary artery. The hemodynamics and respiratory status of the animals during support with the device gas transfer performance of the PediPL were studied for 4 h. The animals exhibited respiratory failure 30 min after mechanical ventilation was reduced to 2 breaths/min, indicated by low oxygen partial pressure, low oxygen saturation, and elevated carbon dioxide in arterial blood. The failure was reversed by establishing respiratory support with the PediPL after 30 min. The rates of O2 transfer and CO2 removal of the PediPL were 86.8 and 139.1 mL/min, respectively. The results demonstrated that the PediPL (miniature integrated pump-oxygenator) has the potential to provide respiratory support as a novel treatment for both hypoxia and hypercarbia. The compact size of the PediPL could allow portability and potentially be used in many emergency settings to rescue patients suffering acute lung injury.

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.

[SYNDROMAL APPROACH IN ULTRASONOGRAPHIC DIAGNOSIS OF THORACIC TRAUMA].

Diagnosis of the thoracic organs injuries constitute an actual problem of modern medicine. Results of examination of 96 injured persons, suffering thoracic cavity organs trauma, were analyzed. Ultrasonographic investigation conduction in complex with radiological methods, basing on syndromal diagnostic approach, have permitted to enhance diagnostic informativity significantly, to obtain objective data about character of the injury, and to establish adequate tactics of treatment for the injured persons, basing on analysis of the results achieved.

Inhibiting Integrin αvß5 Reduces Ischemia-Reperfusion Injury in an Orthotopic Lung Transplant Model in Mice.

Primary graft dysfunction after lung transplantation is the leading cause of morbidity and mortality in the immediate posttransplant period and is characterized by endothelial and epithelial barrier disruption and the leakage of protein-rich edema fluid. Integrins are cell surface receptors that have an important role in maintenance of the cell barrier, and inhibition of integrins, such as αvß5, can diminish alveolar flooding in lung injury models. We hypothesized that inhibition of αvß5 during donor lung cold ischemia would reduce endothelial permeability during reperfusion. Using an orthotopic single lung transplantation model with and without cold ischemia, donor lungs were perfused with αvß5-blocking antibody (ALULA) or control antibody at the time of collection, followed by transplantation, 8 h of reperfusion, and the measurement of lung injury parameters. Prolonged cold ischemia (18 h) produced increases in extravascular lung water, protein permeability, and neutrophilic alveolitis and decreased oxygenation compared with lungs without cold ischemia. Perfusion of lungs with αvß5 antibody versus control antibody protected donor lungs from injury and significantly improved oxygenation. In summary, αvß5 integrin blockade protects from the development of ischemia-reperfusion lung injury and is a promising approach to preventing primary graft dysfunction in human lung transplant procedures.

Mesenchymal Stem Cells and Lung Transplantation: A Couple for a Perfect Relationship.

With the increased incidence of lung and other organ failure, organ transplantation becomes a frequent surgical intervention. Research is focused on improving the practice of lung and other organ transplantation in order to improve the clinical outcome and to decrease the incidence of post-operative complications. This manuscript represents the author's view of the possibility of improving the lung transplantation outcome through the co-transplantation of mesenchymal stem cells, and the expected positive effects of that application.