Inflammation and the acute respiratory distress syndrome

Transferring an extremely premature infant to an extra-uterine life support system: a prospective view on the obstetric procedure

To improve care for extremely premature infants, the development of an extrauterine environment for newborn development is being researched, known as Artificial Placenta and Artificial Womb (APAW) technology. APAW facilitates extended development in a liquid-filled incubator with oxygen and nutrient supply through an oxygenator connected to the umbilical vessels. This setup is intended to provide the optimal environment for further development, allowing further lung maturation by delaying gas exposure to oxygen. This innovative treatment necessitates interventions in obstetric procedures to transfer an infant from the native to an artificial womb, while preventing fetal-to-neonatal transition. In this narrative review we analyze relevant fetal physiology literature, provide an overview of insights from APAW studies, and identify considerations for the obstetric procedure from the native uterus to an APAW system. Lastly, this review provides suggestions to improve sterility, fetal and maternal well-being, and the prevention of neonatal transition.

Possible cancer-causing capacity of COVID-19: Is SARS-CoV-2 an oncogenic agent?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has shown diverse life-threatening effects, most of which are considered short-term. In addition to its short-term effects, which has claimed many millions of lives since 2019, the long-term complications of this virus are still under investigation. Similar to many oncogenic viruses, it has been hypothesized that SARS-CoV-2 employs various strategies to cause cancer in different organs. These include leveraging the renin angiotensin system, altering tumor suppressing pathways by means of its nonstructural proteins, and triggering inflammatory cascades by enhancing cytokine production in the form of a "cytokine storm" paving the way for the emergence of cancer stem cells in target organs. Since infection with SARS-CoV-2 occurs in several organs either directly or indirectly, it is expected that cancer stem cells may develop in multiple organs. Thus, we have reviewed the impact of coronavirus disease 2019 (COVID-19) on the vulnerability and susceptibility of specific organs to cancer development. It is important to note that the cancer-related effects of SARS-CoV-2 proposed in this article are based on the ability of the virus and its proteins to cause cancer but that the long-term consequences of this infection will only be illustrated in the long run.

Synergistic Pulmonoprotective Effect of Natural Prolyl Oligopeptidase Inhibitors in In Vitro and In Vivo Models of Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is a highly morbid inflammatory lung disease with limited pharmacological interventions. The present study aims to evaluate and compare the potential pulmonoprotective effects of natural prolyl oligopeptidase (POP) inhibitors namely rosmarinic acid (RA), chicoric acid (CA), epigallocatechin-3-gallate (EGCG) and gallic acid (GA), against lipopolysaccharide (LPS)-induced ARDS. Cell viability and expression of pro-inflammatory mediators were measured in RAW264.7 cells and in primary murine lung epithelial and bone marrow cells. Nitric oxide (NO) production was also assessed in unstimulated and LPS-stimulated RAW264.7 cells. For subsequent in vivo experiments, the two natural products (NPs) with the most favorable effects, RA and GA, were selected. Protein, cell content and lipid peroxidation levels in bronchoalveolar lavage fluid (BALF), as well as histopathological changes and respiratory parameters were evaluated in LPS-challenged mice. Expression of key mediators involved in ARDS pathophysiology was detected by Western blotting. RA and GA favorably reduced gene expression of pro-inflammatory mediators in vitro, while GA decreased NO production in macrophages. In LPS-challenged mice, RA and GA co-administration improved respiratory parameters, reduced cell and protein content and malondialdehyde (MDA) levels in BALF, decreased vascular cell adhesion molecule-1 (VCAM-1) and the inducible nitric oxide synthase (iNOS) protein expression, activated anti-apoptotic mechanisms and down-regulated POP in the lung. Conclusively, these synergistic pulmonoprotective effects of RA and GA co-administration could render them a promising prophylactic/therapeutic pharmacological intervention against ARDS.

CNP-miR146a Decreases Inflammation in Murine Acute Infectious Lung Injury

Acute respiratory distress syndrome (ARDS) has approximately 40% in-hospital mortality, and treatment is limited to supportive care. Pneumonia is the underlying etiology in many cases with unrestrained inflammation central to the pathophysiology. We have previously shown that CNP-miR146a, a radical scavenging cerium oxide nanoparticle (CNP) conjugated to the anti-inflammatory microRNA(miR)-146a, reduces bleomycin- and endotoxin-induced acute lung injury (ALI) by decreasing inflammation. We therefore hypothesized that CNP-miR146a would decrease inflammation in murine infectious ALI. Mice were injured with intratracheal (IT) MRSA or saline followed by treatment with IT CNP-miR146a or saline control. Twenty-four hours post-infection, bronchoalveolar lavage fluid (BALF) and whole lungs were analyzed for various markers of inflammation. Compared to controls, MRSA infection significantly increased proinflammatory gene expression (IL-6, IL-8, TNFα, IL-1β; p < 0.05), BALF proinflammatory cytokines (IL-6, IL-8, TNFα, IL-1β; p < 0.01), and inflammatory cell infiltrate (p = 0.03). CNP-miR146a treatment significantly decreased proinflammatory gene expression (IL-6, IL-8, TNFα, IL-1β; p < 0.05), bronchoalveolar proinflammatory protein leak (IL-6, IL-8, TNFα; p < 0.05), and inflammatory infiltrate (p = 0.01). CNP-miR146a decreases inflammation and improves alveolar-capillary barrier integrity in the MRSA-infected lung and has significant promise as a potential therapeutic for ARDS.

Precision Medicine Using Simultaneous Monitoring and Assessment with Imaging and Biomarkers to Manage Mechanical Ventilation in ARDS

Acute respiratory distress syndrome (ARDS) has a ~ 40% mortality rate with an increasing prevalence exacerbated by the COVID-19 pandemic. Mechanical ventilation is the primary means for life-saving support to buy time for lung healing in ARDS patients, however, it can also lead to ventilator-induced lung injury (VILI). Effective strategies to reduce or prevent VILI are necessary but are not currently delivered. Therefore, we aim at evaluating the current imaging technologies to visualize where pressure and volume being delivered to the lung during mechanical ventilation; and combining plasma biomarkers to guide management of mechanical ventilation. We searched PubMed and Medline using keywords and analyzed the literature, including both animal models and human studies, to examine the independent use of computed tomography (CT) to evaluate lung mechanics, electrical impedance tomography (EIT) to guide ventilation, ultrasound to monitor lung injury, and plasma biomarkers to indicate status of lung pathophysiology. This investigation has led to our proposal of the combination of imaging and biomarkers to precisely deliver mechanical ventilation to improve patient outcomes in ARDS.

Early and Dose-Dependent Xenogeneic Mesenchymal Stem Cell Therapy Improved Outcomes in Acute Respiratory Distress Syndrome Rodent Through Ameliorating Inflammation, Oxidative Stress, and Immune Reaction

This study tested whether human umbilical cord-derived mesenchymal stem cells (HUCDMSCs) treatment effectively protected the rat lung against acute respiratory distress syndrome (ARDS) injury, and benefits of early and dose-dependent treatment. Rat pulmonary epithelial cell line L2 (PECL2) were categorized into G1 (PECL2), G2 (PECL2 + healthy rat lung-derived extraction/50 mg/ml co-cultured for 24 h), G3 (PECL2 + ARDS rat lung-derived extraction/50 mg/ml co-cultured for 24 h), and G4 (condition as G3 + HUCDMSCs/1 × 105/co-cultured for 24 h). The result showed that the protein expressions of inflammatory (HMGB-1/TLR-2/TLR-4/MAL/TRAM/MyD88/TRIF/TRAF6/IkB/NF-κB/IL-1β/TNF-α), oxidative-stress/mitochondrial-damaged (NOX-1/NOX-2/ASK1/p-MKK4/p-MKK7/JNKs/JUN/cytosolic-cytochrome-C/cyclophilin-D/DRP1), and cell-apoptotic/fibrotic (cleaved-caspase 3/cleaved-PARP/TGF-β/p-Smad3) biomarkers were significantly increased in G3 than in G1/G2 and were significantly reversed in G4 (all P < 0.001), but they were similar between G1/G2. Adult male rats (n = 42) were equally categorized into group 1 (normal control), group 2 (ARDS only), group 3 [ARDS + HUCDMSCs/1.2 × 106 cells intravenous administration at 3 h after 48 h ARDS induction (i.e., early treatment)], group 4 [ARDS + HUCDMSCs/1.2 × 106 cells intravenous administration at 24 h after 48 h ARDS induction (late treatment)], and group 5 [ARDS + HUCDMSCs/1.2 × 106 cells intravenous administration at 3 h/24 h after-48 h ARDS induction (dose-dependent treatment)]. By day 5 after ARDS induction, the SaO2%/immune regulatory T cells were highest in group 1, lowest in group 2, significantly lower in group 4 than in groups 3/5, and significantly lower in group 3 than in group 5, whereas the circulatory/bronchioalveolar lavage fluid inflammatory cells (CD11b-c+/LyG6+/MPO+)/circulatory immune cells (CD3-C4+/CD3-CD8+)/lung-leakage-albumin level/lung injury score/lung protein expressions of inflammatory (HMGB-1/TLR-2/TLR-4/MAL/TRAM/MyD88/TRIF/TRAF6/IκB-β/p-NF-κB/IL-1β/TNF-α)/fibrotic (p-SMad3/TGF-β), apoptosis (mitochondrial-Bax/cleaved-caspase-3)/oxidative-cell-stress (NOX-1/NOX-2/ASK1/p-MKK4/p-MKK7/p-JNKs/p-cJUN)/mitochondrial damaged (cyclophilin-D/DRP1/cytosolic-cytochrome-C) biomarkers displayed an opposite pattern of SaO2% among the groups (all P < 0.0001). Early administration was superior to and two-dose counterpart was even more superior to late HUCDMSCs treatment for protecting the lung against ARDS injury.

Ferret acute lung injury model induced by repeated nebulized lipopolysaccharide administration

Inflammatory lung diseases affect millions of people worldwide. These diseases are caused by a number of factors such as pneumonia, sepsis, trauma, and inhalation of toxins. Pulmonary function testing (PFT) is a valuable functional methodology for better understanding mechanisms of lung disease, measuring disease progression, clinical diagnosis, and evaluating therapeutic interventions. Animal models of inflammatory lung diseases are needed that accurately recapitulate disease manifestations observed in human patients and provide an accurate prediction of clinical outcomes using clinically relevant pulmonary disease parameters. In this study, we evaluated a ferret lung inflammation model that closely represents multiple clinical manifestations of acute lung inflammation and injury observed in human patients. Lipopolysaccharide (LPS) from Pseudomonas aeruginosa was nebulized into ferrets for 7 repeated daily doses. Repeated exposure to nebulized LPS resulted in a restrictive pulmonary injury characterized using Buxco forced maneuver PFT system custom developed for ferrets. This is the first study to report repeated forced maneuver PFT in ferrets, establishing lung function measurements pre- and post-injury in live animals. Bronchoalveolar lavage and histological analysis confirmed that LPS exposure elicited pulmonary neutrophilic inflammation and structural damage to the alveoli. We believe this ferret model of lung inflammation, with clinically relevant disease manifestations and parameters for functional evaluation, is a useful pre-clinical model for understanding human inflammatory lung disease and for the evaluation of potential therapies.

Effects of tocilizumab and dexamethasone on the downregulation of proinflammatory cytokines and upregulation of antioxidants in the lungs in oleic acid-induced ARDS

Background

Acute respiratory distress syndrome (ARDS) is a life-threatening disease caused by the induction of inflammatory cytokines and chemokines in the lungs. There is a dearth of drug applications that can be used to prevent cytokine storms in ARDS treatment. This study was designed to investigate the effects of tocilizumab and dexamethasone on oxidative stress, antioxidant parameters, and cytokine storms in acute lung injury caused by oleic acid in rats.

Methods

Adult male rats were divided into five groups: the CN (healthy rats, n = 6), OA (oleic acid administration, n = 6), OA + TCZ-2 (oleic acid and tocilizumab at 2 mg/kg, n = 6), OA + TCZ-4 (oleic acid and tocilizumab at 4 mg/kg, n = 6), and OA + DEX-10 (oleic acid and dexamethasone at 10 mg/kg, n = 6) groups. All animals were euthanized after treatment for histopathological, immunohistochemical, biochemical, PCR, and SEM analyses.

Results

Expressions of TNF-α, IL-1β, IL-6, and IL-8 cytokines in rats with acute lung injury induced by oleic acid were downregulated in the TCZ and DEX groups compared to the OA group (P < 0.05). The MDA level in lung tissues was statistically lower in the OA + TCZ-4 group compared to the OA group. It was further determined that SOD, GSH, and CAT levels were decreased in the OA group and increased in the TCZ and DEX groups (P < 0.05). Histopathological findings such as thickening of the alveoli, hyperemia, and peribronchial cell infiltration were found to be similar when lung tissues of the TCZ and DEX groups were compared to the control group. With SEM imaging of the lung tissues, it was found that the alveolar lining layer had become indistinct in the OA, OA + TCZ-2, and OA + TCZ-4 groups.

Conclusions

In this model of acute lung injury caused by oleic acid, tocilizumab and dexamethasone were effective in preventing cytokine storms by downregulating the expression of proinflammatory cytokines including TNF-α, IL-1β, IL-6, and IL-8. Against the downregulation of antioxidant parameters such as SOD and GSH in the lung tissues caused by oleic acid, tocilizumab and dexamethasone upregulated them and showed protective effects against cell damage.

ARDS associated acute brain injury: from the lung to the brain

A complex interrelation between lung and brain in patients with acute lung injury (ALI) has been established by experimental and clinical studies during the last decades. Although, acute brain injury represents one of the most common insufficiencies in patients with ALI and acute respiratory distress syndrome (ARDS), the underlying pathophysiology of the observed crosstalk remains poorly understood due to its complexity. Specifically, it involves numerous pathophysiological parameters such as hypoxemia, neurological adverse events of lung protective ventilation, hypotension, disruption of the BBB, and neuroinflammation in such a manner that the brain of ARDS patients-especially hippocampus-becomes very vulnerable to develop secondary lung-mediated acute brain injury. A protective ventilator strategy could reduce or even minimize further systemic release of inflammatory mediators and thus maintain brain homeostasis. On the other hand, mechanical ventilation with low tidal volumes may lead to self-inflicted lung injury, hypercapnia and subsequent cerebral vasodilatation, increased cerebral blood flow, and intracranial hypertension. Therefore, by describing the pathophysiology of ARDS-associated acute brain injury we aim to highlight and discuss the possible influence of mechanical ventilation on ALI-associated acute brain injury.

P50 implies adverse clinical outcomes in pediatric acute respiratory distress syndrome by reflecting extrapulmonary organ dysfunction

Hypoxemia and multiple organ dysfunction are significant contributors to mortality in patients with pediatric acute respiratory distress syndrome (PARDS). P50, the oxygen tension at which hemoglobin is 50% saturated, is a measure of hemoglobin-oxygen affinity, and its alteration might have implications for tissue hypoxia and organ dysfunction. The purpose of this single-center, retrospective study was to evaluate P50 levels in PARDS and to determine the association between P50 and clinical outcomes. The study included 212 children diagnosed with PARDS according to the Pediatric Acute Lung Injury Consensus Conference definition who required invasive mechanical ventilation and had arterial blood gas results of hemoglobin oxygen saturation < 97% at the time of diagnosis. P50 levels were calculated using Doyle’s method, and organ dysfunction was assessed using the Pediatric Logistic Organ Dysfunction-2 score. Most patients exhibited more than one dysfunctional extrapulmonary organ at PARDS onset. P50 increased with increasing PARDS severity (mild (26.6 [24.9–29.6]), moderate (26.8 [25.0–29.5]), and severe PARDS (29.1 [26.1–32.4] mmHg; P = 0.025). Moreover, P50 demonstrated a significant positive association with extrapulmonary organ dysfunction score (β = 0.158, P = 0.007) and risk of mortality (adjusted hazard ratio, 1.056; 95% confidence interval, 1.015–1.098; P = 0.007), irrespective of initial PARDS severity. The relationship between P50 and mortality was largely mediated by extrapulmonary organ dysfunction. A high P50 value at the time of PARDS diagnosis may be associated with mortality via dysfunctional extrapulmonary organs. Future studies should consider P50 as a potential candidate index for risk stratification of PARDS patients.

SRC3 deficiency exacerbates lipopolysaccharide-induced acute respiratory distress syndrome in mice

Acute respiratory distress syndrome (ARDS) is a severe disease. Inflammation is the key element implicated in ARDS. Steroid receptor coactivator 3 (SRC3), a coactivator protein for transcription, is involved in regulation of inflammatory response. Here we explored the potential roles of SRC3 in ARDS. We utilized the SRC3 deficient (SRC3^-/-) mice and established the lipopolysaccharides (LPS)-induced ARDS model. The mortality, lung injury, leucocytes infiltration and inflammatory cytokine production were compared between wild type (WT) and SRC3^-/- mice. The NF-κB activation in lung of WT and SRC3^-/- mice was measured. After LPS treatment, SRC3^-/- mice had higher mortality and more severe lung damage than WT mice. LPS-treated SRC3^-/- mice had more leucocytes infiltration and upregulated inflammatory cytokine production. LPS-treated SRC3^-/- mice had elevated NF-κB activation. SRC3^-/- mice had exacerbated ARDS in LPS-treated mice.

Immunomodulatory activity of β-glucan polysaccharides isolated from different species of mushroom - A potential treatment for inflammatory lung conditions

Acute respiratory distress syndrome (ARDS) is the most common form of acute severe hypoxemic respiratory failure in the critically ill with a hospital mortality of 40%. Alveolar inflammation is one of the hallmarks for this disease. β-Glucans are polysaccharides isolated from a variety of natural sources including mushrooms, with documented immune modulating properties. To investigate the immunomodulatory activity of β-glucans and their potential as a treatment for ARDS, we isolated and measured glucan-rich polysaccharides from seven species of mushrooms. We used three models of in-vitro injury in THP-1 macrophages, Peripheral blood mononuclear cells (CD14+) (PMBCs) isolated from healthy volunteers and lung epithelial cell lines. We observed variance between β-glucan content in extracts isolated from seven mushroom species. The extracts with the highest β-glucan content found was Lentinus edodes which contained 70% w/w and Hypsizygus tessellatus which contained 80% w/w with low levels of α-glucan. The extracts had the ability to induce secretion of up to 4000 pg/mL of the inflammatory cytokine IL-6, and up to 5000 pg/mL and 500 pg/mL of the anti-inflammatory cytokines IL-22 and IL-10, respectively, at a concentration of 1 mg/mL in THP-1 macrophages. In the presence of cytokine injury, IL-8 was reduced from 15,000 pg/mL to as low as 10,000 pg/mL in THP-1 macrophages. After insult with LPS, phagocytosis dropped from 70-90% to as low 10% in CD14+ PBMCs. After LPS insult CCL8 relative gene expression was reduced, and IL-10 relative gene expression increased from 50 to 250-fold in THP-1 macrophages. In lung epithelial cells, both A549 and BEAS-2B after IL-1β insult, IL-8 levels dropped from 10,000 pg/mL to as low as 6000 pg/mL. TNF-α levels dropped 10-fold from 100 pg/mL to just below 10 pg/mL. These results demonstrate the therapeutic potential of β-glucans in inflammatory lung conditions. Findings also advance bio-based research that connects green innovation with One Health applications for the betterment of society.

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.

FUNDC1 Regulates Autophagy by Inhibiting ROS-NLRP3 Signaling to Avoid Apoptosis in the Lung in a Lipopolysaccharide-Induced Mouse Model

ABSTRACT

The incidence and mortality of acute respiratory distress syndrome (ARDS) are high, but the relevant mechanism for this disorder remains unclear. Autophagy plays an important role in the development of ARDS. The mitochondrial outer membrane protein FUNDC1 is involved in hypoxia-mediated mitochondrial autophagy, which may contribute to ARDS development. This study explored whether FUNDC1 regulates autophagy by inhibiting ROS-NLRP3 signaling to avoid apoptosis in the lung in a lipopolysaccharide-induced mouse model. In this study, FUNDC1 knockout mice were constructed, and a lipopolysaccharide-induced mouse model was generated. HE staining of pathological sections from the lung, wet/dry lung measurements, myeloperoxidase concentration/neutrophil counts in BALF and survival time of mice were examined to determine the effect of modeling. The release of cytokines (TNF-α, IL-1β, IL-6, and IL-10) in response to LPS in the BALF and plasma was assessed using ELISA. The effects of oxidative stress (malondialdehyde, superoxide dismutase, catalase, glutathione peroxidase) in lung tissue in response to LPS were detected by biochemical analysis. Oxidative stress damage was validated by iNOS staining, and apoptosis was assessed by TUNEL staining after LPS. Finally, the expression of autophagy-associated proteins and inflammasome-associated proteins in lung tissue after LPS intervention was analyzed by western blot. We found that wild-type control, FUNDC1 knockout control, lipopolysaccharide-induced wild-type, and FUNDC1 knockout mouse models were used to investigate whether FUNDC1-mediated autophagy is involved in lung injury and its possible molecular mechanisms. Compared with the normal control group, lung tissue FUNDC1 and LC3 II increased and p62/SQSTM1 decreased after LPS intervention, and increased ROS levels led to a decrease in corresponding antioxidant enzymes along with an increased inflammatory response and apoptosis. Levels of autophagy in lipopolysaccharide-induced mice deficient in FUNDC1 were significantly decreased, but the expression of ROS and inflammatory factors in lung tissue was more severe than in lipopolysaccharide-induced wild-type mice, and the survival rate was significantly decreased. Western blot analysis showed that autophagy was significantly inhibited in the FUNDC1 KO+LPS group, and there was a significant increase in NLRP3, caspase-1, IL-1β, and ASC compared with the lipopolysaccharide-induced wild-type group. In summary, lipopolysaccharide-induced wild-type mice exhibit ROS-dependent activation of autophagy, and knocking out FUNDC1 promotes inflammasome activation and exacerbates lung injury.

Atractylenolide III alleviates sepsis-mediated lung injury via inhibition of FoxO1 and VNN1 protein

PURPOSE

To evaluate the influence of atractylenolide (Atr) III on sepsis-induced lung damage.

METHODS

We constructed a mouse sepsis model through cecal ligation and puncture. These mice were allocated to the normal, sepsis, sepsis + Atr III-L (2 mg/kg), as well as Atr III-H (8 mg/kg) group. Lung injury and pulmonary fibrosis were accessed via hematoxylin-eosin (HE) and Masson's staining. We used terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and flow cytometry for detecting sepsis-induced lung cell apoptosis. The contents of the inflammatory cytokines in lung tissue were measured via enzyme-linked immunosorbent assay (ELISA).

RESULTS

Atr III-H did not only reduce sepsis-induced lung injury and apoptosis level, but also curbed the secretion of inflammatory factors. Atr III-H substantially ameliorated lung function and raised Bcl-2 expression. Atr III-H eased the pulmonary fibrosis damage and Bax, caspase-3, Vanin-1 (VNN1), as well as Forkhead Box Protein O1 (FoxO1) expression.

CONCLUSIONS

Atr III alleviates sepsis-mediated lung injury via inhibition of FoxO1 and VNN1 protein.

COVID-19-related cardiac complications from clinical evidences to basic mechanisms: opinion paper of the ESC Working Group on Cellular Biology of the Heart

The pandemic of coronavirus disease (COVID)-19 is a global threat, causing high mortality, especially in the elderly. The main symptoms and the primary cause of death are related to interstitial pneumonia. Viral entry also into myocardial cells mainly via the angiotensin converting enzyme type 2 (ACE2) receptor and excessive production of pro-inflammatory cytokines, however, also make the heart susceptible to injury. In addition to the immediate damage caused by the acute inflammatory response, the heart may also suffer from long-term consequences of COVID-19, potentially causing a post-pandemic increase in cardiac complications. Although the main cause of cardiac damage in COVID-19 remains coagulopathy with micro- (and to a lesser extent macro-) vascular occlusion, open questions remain about other possible modalities of cardiac dysfunction, such as direct infection of myocardial cells, effects of cytokines storm, and mechanisms related to enhanced coagulopathy. In this opinion paper, we focus on these lesser appreciated possibilities and propose experimental approaches that could provide a more comprehensive understanding of the cellular and molecular bases of cardiac injury in COVID-19 patients. We first discuss approaches to characterize cardiac damage caused by possible direct viral infection of cardiac cells, followed by formulating hypotheses on how to reproduce and investigate the hyperinflammatory and pro-thrombotic conditions observed in the heart of COVID-19 patients using experimental in vitro systems. Finally, we elaborate on strategies to discover novel pathology biomarkers using omics platforms.

How could perfluorocarbon affect cytokine storm and angiogenesis in coronavirus disease 2019 (COVID-19): role of hypoxia-inducible factor 1α

Coronavirus disease 2019 (COVID-19) pandemic is still a world-class challenge. Inflammation, especially its severe form with excess release of pro-inflammatory cytokines (cytokine storm) which is a life-threatening condition, is among the most important suspects involved in COVID-19 pathogenesis. It has been shown that cytokine storm could cause notable morbidities such as acute respiratory distress syndrome (ARDS) which leads to hypoxia which is significantly associated with mortality of patients with COVID-19. Hypoxia-inducible factor 1α (HIF-1α) which activates following ARDS-induced hypoxia plays a crucial role in pathogenesis of cytokine storm. The expression of tumor necrosis factor α (TNF-α), interleukin 1 β (IL-1β), and IL-6 which are key elements of cytokine storm are by nuclear factor κβ (NFκB). Interestingly, during the hypoxia, HIF-1α activates NFκB to induce expression of pro-angiogenic and pro-inflammatory factors. These released factors starts a autocrine/paracrine loop and causes deterioration of their etiological pathways of expression: cytokine storm and ARDS. To sum up, it seems HIF-1α is an important target to hit to ameliorate the mentioned pathways. Herein, we suggest perfluorocarbons (PFCs) which are among the organofluorine compounds as a possible co-treatment to reduce hypoxemia and then hypoxia. These substances are known for their high gas solving potential that make them able to be used as a synthetic artificial blood product. Due to the potential of PFCs to affect the fountain of important physiopathological pathway such as inflammation a hypoxia through affecting NFκB, they could be considered as multi-target co-treatment for ARD individuals with COVID-19. It is highly suggested to evaluate this hypothesis in following researches.

Cerium oxide nanoparticle delivery of microRNA-146a for local treatment of acute lung injury

Acute respiratory distress syndrome (ARDS) is a devastating pulmonary disease with significant in-hospital mortality and is the leading cause of death in COVID-19 patients. Excessive leukocyte recruitment, unregulated inflammation, and resultant fibrosis contribute to poor ARDS outcomes. Nanoparticle technology with cerium oxide nanoparticles (CNP) offers a mechanism by which unstable therapeutics such as the anti-inflammatory microRNA-146a can be locally delivered to the injured lung without systemic uptake. In this study, we evaluated the potential of the radical scavenging CNP conjugated to microRNA-146a (termed CNP-miR146a) in preventing acute lung injury (ALI) following exposure to bleomycin. We have found that intratracheal delivery of CNP-miR146a increases pulmonary levels of miR146a without systemic increases, and prevents ALI by altering leukocyte recruitment, reducing inflammation and oxidative stress, and decreasing collagen deposition, ultimately improving pulmonary biomechanics.

Diffuse Alveolar Damage Correlation with Clinical Diagnosis of Pediatric Acute Respiratory Distress Syndrome

Diffuse alveolar damage (DAD) is one of the pathological hallmarks of acute respiratory distress syndrome (ARDS). We aimed to compare pathological findings of DAD with clinical ARDS criteria. We re-evaluated 20 patients whose clinical autopsy revealed DAD. Total 11/20 patients with DAD (55%) met the 1994 American-European Consensus Conference and 7/17 (41%) met the 2012 Berlin clinical criteria. DAD showed only moderate correlation with current clinical ARDS definition. Oxygenation index (OI), seems to be the most valuable tool in predicting pulmonary damage severity, though OI is not listed in either of the previous definitions. We support the recommended use of OI by 2015 consensus conference.

How Do Inflammatory Mediators, Immune Response and Air Pollution Contribute to COVID-19 Disease Severity? A Lesson to Learn

Inflammatory and immune processes are defensive mechanisms that aim to remove harmful agents. As a response to infections, inflammation and immune response contribute to the pathophysiological mechanisms of diseases. Coronavirus disease 2019 (COVID-19), whose underlying mechanisms remain not fully elucidated, has posed new challenges for the knowledge of pathophysiology. Chiefly, the inflammatory process and immune response appear to be unique features of COVID-19 that result in developing a hyper-inflammatory syndrome, and air pollution, the world's largest health risk factor, may partly explain the behaviour and fate of COVID-19. Understanding the mechanisms involved in the progression of COVID-19 is of fundamental importance in order to avoid the late stage of the disease, associated with a poor prognosis. Here, the role of the inflammatory and immune mediators in COVID-19 pathophysiology is discussed.

Multiple organ dysfunction syndrome: Contemporary insights on the clinicopathological spectrum

Multiorgan dysfunction syndrome (MODS) remains a major complication and challenge to treat patients with critical illness in different intensive care unit settings. The exact mechanism and pathophysiology of MODS is complex and remains unexplored. We reviewed the literature from January 2011 to August 2019 to analyze the underlying mechanisms, prognostic factors, MODS scoring systems, organ systems dysfunctions, and the management of MODS. We used the search engines PubMed, MEDLINE, Scopus, and Google Scholar with the keywords "multiple organ dysfunction syndrome," "intensive care units," "multiorgan failure," "MODS scoring system," and "MODS management." The initial search yielded 3550 abstracts, of which 91 articles were relevant to the scope of the present article. A better understanding of a disease course will help differentiate the signs of an intense inflammatory response from the early onset of sepsis and minimize the inappropriate use of medications. This, in turn, will promote organtargeted therapy and prevent occurrence and progression of MODS.

LincRNA-p21 promotes classical macrophage activation in acute respiratory distress syndrome by activating NF-κB

Background: Previous studies have revealed the important role of alveolar macrophages (AMs) in the pathogenesis of acute respiratory distress syndrome (ARDS) and potential anti-inflammatory properties of lincRNA-p21. This study aims to study the association between lincRNA-p21 and active AMs to understand the molecular mechanisms of AMs-mediated inflammatory responses in ARDS.Methods: This study was mainly investigated in mice with the intratracheal instillation of lipopolysaccharide (LPS) or LPS-treated AMs. The expression of lincRNA-p21 and classical macrophage markers, IL-12β and iNOS, was detected by quantitative RT-PCR, while NF-κB p65 translocation was measured by western blotting analysis. And, NF-κB activity was analyzed through luciferase report assays. Gain- and loss-of-function studies were also performed for further investigations.Results: Elevated lincRNA-p21 levels were observed in both LPS-induced ARDS mice and LPS-treated AMs, with upregulated expression of IL-12β and iNOS, namely M1 activation, and p65 nuclear translocation. Further in vitro studies showed that LPS-induced M1 activation could be counteracted by both lincRNA-p21 inhibition and inhibited NF-κB activation. Moreover, both p65 nuclear translocation and NF-κB activity were promoted by lincRNA-p21 overexpression, while lincRNA-p21 inhibition showed a negative effect on LPS-induced p65 nuclear translocation and increase of NF-κB activity. Additionally, LPS-induced lung injuries could be attenuated by lincRNA-p21 inhibition in vivo.Conclusion: This study revealed elevated lincRNA-p21 levels in LPS-induced ARDS and investigated the potential role of lincRNA-p21 in LPS-induced pro-inflammatory response via NF-κB/p65 mediated pathways, suggesting the potential application of lincRNA-p21 for ADRS therapy.

Study on the Protective Effect of Special Electromagnetic Field Treated Water and Far Infrared Rays on LPS-Induced ARDS Rats

Objective

To explore the protective effect of special electromagnetic field treated water (SEW) and far infrared rays (IFR) on endotoxin (lipopolysaccharide, LPS) induced ARDS rats and the effect on inflammatory factors.

Methods

40 healthy male SD rats were randomly divided into 4 groups with 10 in each group. Preventive experiment: Adaptive feeding was carried out for 1 week according to animal feeding standards. Rats in SEW group drank SEW daily. Samely, rats in SEW and FIR group also drank SEW daily. Besides, rats in SEW and FIR group were also given far infrared rays for 20min/d. Rats in model group drank distilled water daily. After 7 days, rats in each group were injected with LPS (2 mg/kg) via the tail vein for making models. Rats in blank control group were given distilled water for 7 days, without modeling. All rats in the 4 groups were put to death under anesthesia 16 hours after modeling. Lung tissue and abdominal aortic blood were taken from these rats.

Results

Pathological observation of lung and lung tissue indicated that rats in model group showed great pathological difference from rats in blank group. Rats in intervention group showed more symptomatic improvement in relation to alveolar and pulmonary interstitial congestion, edema, and inflammatory cell infiltration than rats in model group. The level of inflammatory factors like IL-1β and IL-6 in serum of rats in model group increased compared to blank control group (p<0.05). Comparing SEW group and SEW and FIR group with model group, levels of IL-1β and IL-6 in serum of rats both decreased remarkably (IL-Iβ: P < 0.05; IL-6: P < 0.01) while there was no obvious difference between SEW group and SEW and FIR group (p>0.05). The lung coefficient (LI) in SEW and FIR group was significantly lower than that in model group (P<0.01), which was higher than that of blank control group (P < 0.05), while there was no obvious difference between model group and SEW group (P>0.05). Compared with blank control group, lung permeability index (LPI) in model group showed no obvious difference (P>0.05).

Conclusion

Special electromagnetic field treated water and far infrared rays can alleviate lung tissue damage of endotoxin-induced ARDS rats, relieving symptoms of alveolar and pulmonary interstitial congestion, edema, and inflammatory cell infiltration. The protective effect of special electromagnetic field treated water and far infrared rays on endotoxin-induced acute respiratory distress syndrome may result from their role in reducing the levels of IL-1β and IL-6 in serum and the expression level of p65 protein in lung tissue, in addition to reliving inflammatory response, lung coefficient, and lungs edema.

SOCS-1 Suppresses Inflammation Through Inhibition of NALP3 Inflammasome Formation in Smoke Inhalation-Induced Acute Lung Injury

Smoke inhalation leads to acute lung injury (ALI), a devastating clinical problem associated with high mortality rates. Suppressor of cytokine signaling-1 (SOCS-1) is a negative regulator of proinflammatory cytokine signaling. We have found that adenoviral gene transfer of SOCS-1 ameliorates smoke inhalation-induced lung injury in C57BL/6 mice. We also found that the release of adenosine triphosphate (ATP) was increased post smoke exposure, while oxidized ATP, an inhibitor of purinergic P2X7 receptor, suppressed smoke-induced NALP3 inflammasome assembly, caspase-1 activation, and K⁺ efflux. Similar to oxidized ATP, high protein level of SOCS-1 dampened the formation of NALP3 inflammasome and the activation of caspase-1 and IL-1β induced by smoke exposure in mouse alveolar macrophages. In conclusion, SOCS-1 relieves smoke inhalation-induced pulmonary inflammation and injury by inhibiting NALP3 inflammasome formation.

IL-35 interferes with splenic T cells in a clinical and experimental model of acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a life-threatening critical care syndrome with uncontrolled inflammation that is a central issue. Its main characteristic is inflammatory mediators and cytokines as well as agglutinating chemokines that injure target cells. Interleukin (IL)-35 is a newly identified IL-12 cytokine family member with structural similarities to other IL-12, IL-23, and IL-27 cytokines but unique immunological functions. How IL-35 functions in ARDS is unclear. The purpose of our study was to determine what role IL-35 played in the development of ARDS. Here we found serum IL-35 concentrations were significantly elevated in patients with ARDS relative to healthy people. Moreover, we established a mouse model of lipopolysaccharide- and cecal ligation and puncture-induced ARDS treated with neutralizing antibodies (anti-IL-35 Ebi3 or anti-IL-35 P35); the results showed that lung injury occurred more often than in untreated models and the inflammatory cytokines CXCL-1, tumor necrosis factor alpha, IL-6, and IL-17A increased significantly after neutralizing antibody treatment in bronchoalveolar lavage fluid and serum. Therefore IL-35 can protect against the development of ARDS. Even more interesting in our study was that we discovered IL-35 expression differed between lung and spleen across different ARDS models, which further demonstrated that the spleen likely has an important role in extrapulmonary ARDS model only, improving the ratio of CD4⁺/CD4⁺CD25⁺Foxp3⁺(Tregs). Meanwhile in our clinical work, we also found that the concentration of IL-35 and the ratio of CD4⁺/Treg in the serum are higher and the mortality is lower than those with the spleen deficiency in patients with extrapulmonary ARDS. Therefore, IL-35 is protective in ARDS by promoting the ratio of splenic CD4⁺/Tregs in extrapulmonary ARDS, and as such, may be a therapeutic target.

Pretreatment of ferulic acid attenuates inflammation and oxidative stress in a rat model of lipopolysaccharide-induced acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a fatal clinical condition that can be caused by pulmonary and non-pulmonary diseases. Oxidative stress and inflammation play key roles in the development of ARDS. In this study, we investigated whether ferulic acid (FA), an anti-oxidant, was beneficial for prophylaxis of ARDS. We established an ARDS rat model using lipopolysaccharide (LPS) administration. Lung injury was assessed by lung wet/dry ratio and broncho-alveolar lavage fluid (BALF) analysis. Hematoxylin and eosin staining was performed to evaluate the histological changes of the lungs. Enzyme-linked immunosorbent assay (ELISA) and immunoblotting were performed to detect proteins in BALF and lung tissue, respectively. Pulmonary function was determined by testing the oxygen level in BALF. FA pretreatment significantly alleviated LPS-induced pulmonary histological changes. FA reversed LPS-induced changes of lung wet/dry ratio, total protein in BALF, P(A-a)O₂, and PaO₂/FiO₂. In addition, LPS dramatically up-regulated the secretion of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and IL-10 in BALF (P < 0.01). However, pretreatment of FA significantly improved LPS-induced inflammation. We found that FA indeed reduced oxidative stress in the lungs by testing malondialdehyde level, myeloperoxidase level, and total anti-oxidant capacity. We also proved that FA inactivated multiple mitogen-activated protein kinase signaling pathways in the lungs. In conclusion, FA alleviated LPS-induced ARDS through its anti-inflammatory and anti-oxidant activities.

MicroRNA-92a antagonism attenuates lipopolysaccharide (LPS)-induced pulmonary inflammation and injury in mice through suppressing the PTEN/AKT/NF-κB signaling pathway

Overwhelming lung inflammation is a key feature of acute lung injury (ALI). MicroRNAs (miRNAs) have been implicated in the regulation diverse cellular processes including the inflammatory response. However, little is known about their functions and molecular involvement in regulating the inflammatory process in ALI. Herein, we established a lipopolysaccharide (LPS)-induced ALI mouse model and used miRNA microarray analysis to investigate and compare the miRNA expression profiles in mouse lung tissues. We found that miR-92a was markedly upregulated in the lung tissues of ALI mice compared with that in normal lung tissues. This upregulation of miR-92a in LPS-induced ALI mice was further confirmed in lung tissues, splenocytes and bronchoalveolar lavage fluid (BALF) by quantitative real-time PCR. Inhibition of miR-92a by injection with antagomir-92a markedly reduced LPS-induced pathological changes associated with lung inflammation, and reduces lung wet/dry ratio (W/D ratio), and Evans blue dye extravasation (an indicator of lung epithelial permeability). Moreover, inhibition of miR-92a ameliorated the inflammatory response by reducing the repression of proinflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6 in lung tissues. In addition, we identified that miR-92a inhibited the phosphatase and tensin homolog on chromosome ten (PTEN) by binding to its 3'-UTR in RAW264.7 murine macrophage cells. Western blot analysis demonstrated that inhibition of miR-92a may ameliorate inflammatory response through blocking PTEN/AKT/NF-κB signaling pathway in ALI mice. Collectively, these results have revealed a significant role of miR-92a in the lung inflammatory response associated with ALI in mice, and suggest that miR-92a may have potential as a prognostic indicator and novel therapeutic target for the treatment of ALI in future.

Inflammatory and Fibrinolytic System in Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is the most advanced form of acute lung injury (ALI). This is characterized by bilateral pulmonary infiltrates and severe hypoxemia. According to Berlin definition of ARDS, this is defined based on the timings, radiographic changes, edema formation, and severity on the PaO₂/FiO₂ ratio. During ARDS, the loss of integrity of the epithelium causes the septic shock. The degree of epithelial injury is the major prognostic marker of ARDS. In addition to this, inflammatory cell migration, fibro-proliferation, and activation of apoptosis also play an important role in the pathophysiology of ARDS. The alveolar epithelial cell is the prime target during injury where this cell either undergo apoptosis or epithelial-mesenchymal transition (EMT). Injury to the AECs triggers the changes in the DNA fragmentation and activation of certain apoptotic markers such as caspases at the same time some cells undergo biochemical changes and loses its epithelial morphology as well epithelial biomarkers and gain mesenchymal biomarkers and morphology. In both the cases, the fibrinolytic system plays an important role in maintaining the integrity of the disease process efficiently. This review highlights the research evidence of apoptosis and EMT in lung development, injury and its prognosis in ARDS thereby to develop an effective strategy for the treatment of ARDS.

Photobiomodulation prevents DNA fragmentation of alveolar epithelial cells and alters the mRNA levels of caspase 3 and Bcl-2 genes in acute lung injury

Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are defined as pulmonary inflammation that could occur from sepsis and lead to pulmonary permeability and alveolar edema making them life-threatening diseases. Photobiomodulation (PBM) properties have been widely described in the literature in several inflammatory diseases; although the mechanisms of action are not always clear, this could be a possible treatment for ARDS/ALI. Thus, the aim of this study was to evaluate the mRNA levels from caspase-3 and BCL-2 genes and DNA fragmentation in lung tissue from Wistar rats affected by ALI and subjected to photobiomodulation by exposure to a low power infrared laser (808 nm; 100 mW; 3.571 W cm-2; four points per lung). Adult male Wistar rats were randomized into 6 groups (n = 5, for each group): control, PBM10 (10 J cm-2, 2 J and 2 seconds), PBM20 (20 J cm-2, 5 J and 5 seconds), ALI, ALI + PBM10 and ALI + PBM20. ALI was induced by intraperitoneal Escherichia coli lipopolysaccharide injection. Lung samples were collected and divided for mRNA expression of caspase-3 and Bcl-2 and DNA fragmentation quantifications. Data show that caspase-3 mRNA levels are reduced and Bcl-2 mRNA levels increased in ALI after low power infrared laser exposure when compared to the non-exposed ALI group. DNA fragmentation increased in inflammatory infiltrate cells and reduced in alveolar cells. Our research shows that photobiomodulation can alter relative mRNA levels in genes involved in the apoptotic process and DNA fragmentation in inflammatory and alveolar cells after lipopolysaccharide-induced acute lung injury. Also, inflammatory cell apoptosis is part of the photobiomodulation effects induced by exposure to a low power infrared laser.

Celastrol attenuates impairments associated with lipopolysaccharide-induced acute respiratory distress syndrome (ARDS) in rats

Celastrol, a constituent from a traditional Chinese medicinal herb belonging to the family Celastraceae, has been shown to impart anti-inflammatory properties, in part, by inhibiting NF-κB activity and related induction of pro-inflammatory cytokine formation/release. The present study investigated the effects of celastrol in an animal model of acute respiratory distress syndrome (ARDS) induced by intratracheal administration of lipopolysaccharides (LPSs). Celastrol pre-treatment groups received celastrol by intraperitoneal injection on seven consecutive days before LPS treatment. In rats evaluated 24 h after LPS administration, oxygenation indices and lung injury were measured, as were levels of inflammatory cells and cytokines in isolated bronchoalveolar lavage fluid (BALF). Lung tissue expression of proteins involved in NF-κB and ERK/MAPK pathways were measured by Western blot analyses. Celastrol pre-treatments appeared to attenuate LPS-induced lung injury and inflammatory responses in the rats, including decreases in inducible aggregation\infiltration of inflammatory cells and production/release of pro-inflammatory cytokines into the lung airways. Celastrol appeared to also inhibit NF-κB activation, but had no effect on ERK/MAPK pathways in the LPS-induced ARDS. The results here thus indicated that celastrol pre-treatment could impart protective effects against LPS-induced ARDS, and that these effects may be occurring through an inhibition of induction of NF-κB signaling pathways.

HSP27 inhibitor attenuates radiation-induced pulmonary inflammation

Radiation therapy has been used to treat over 70% of thoracic cancer; however, the method usually causes radiation pneumonitis. In the current study, we investigated the radioprotective effects of HSP27 inhibitor (J2) on radiation-induced lung inflammation in comparison to amifostine. In gross and histological findings, J2 treatment significantly inhibited immune cell infiltration in lung tissue, revealing anti-inflammatory potential of J2. Normal lung volume, evaluated by micro-CT analysis, in J2-treated mice was higher compared to that in irradiated mice. J2-treated mice reversed radiation-induced respiratory distress. However, amifostine did not show significant radioprotective effects in comparison to that of J2. In HSP27 transgenic mice, we observed increased immune cells recruitment and decreased volume of normal lung compared to wild type mice. Increased ROS production and oxidative stress after IR were down-regulated by J2 treatment, demonstrating antioxidant property of J2. The entire data of this study collectively showed that J2 may be an effective therapeutic agent for radiation-induced lung injury.

Advances in Stem Cell and Cell-Based Gene Therapy Approaches for Experimental Acute Lung Injury: A Review of Preclinical Studies

Given the failure of pharmacological interventions in acute respiratory distress syndrome (ARDS), researchers have been actively pursuing novel strategies to treat this devastating, life-threatening condition commonly seen in the intensive care unit. There has been considerable research on harnessing the reparative properties of stem and progenitor cells to develop more effective therapeutic approaches for respiratory diseases with limited treatment options, such as ARDS. This review discusses the preclinical literature on the use of stem and progenitor cell therapy and cell-based gene therapy for the treatment of preclinical animal models of acute lung injury (ALI). A variety of cell types that have been used in preclinical models of ALI, such as mesenchymal stem cells, endothelial progenitor cells, and induced pluripotent stem cells, were evaluated. At present, two phase I trials have been completed and one phase I/II clinical trial is well underway in order to translate the therapeutic benefit gleaned from preclinical studies in complex animal models of ALI to patients with ARDS, paving the way for what could potentially develop into transformative therapy for critically ill patients. As we await the results of these early cell therapy trials, future success of stem cell therapy for ARDS will depend on selection of the most appropriate cell type, route and timing of cell delivery, enhancing effectiveness of cells (i.e., potency), and potentially combining beneficial cells and genes (cell-based gene therapy) to maximize therapeutic efficacy. The experimental models and scientific methods exploited to date have provided researchers with invaluable knowledge that will be leveraged to engineer cells with enhanced therapeutic capabilities for use in the next generation of clinical trials.

Blockade of Interleukin-17 Restrains the Development of Acute Lung Injury

The acute respiratory distress syndrome (ARDS), a clinical complication of severe acute lung injury (ALI) in humans, is a leading cause of morbidity and mortality in critically ill patients. Here, we explored the association between IL-17 and development of ALI using LPS-induced murine model. We found that IL-17 level was elevated in bronchoalveolar lavage (BAL) fluid of ALI mice. Upregulation of IL-17 resulted in increased severity of ALI as evidenced by decreased body weight and survival rate, elevated level of total protein and albumin in BAL fluid, as well as more apparent histopathology changes of lung. Induction of ALI was impaired in IL-17-deficient mice. Management of IL-17 could modulate LPS-induced pulmonary inflammation, as reflected by the total cell and neutrophil counts, proinflammatory cytokines, as well as chemokines in BAL fluid. Of note, blockade of IL-17 effectively inhibited the lung inflammation and alleviated ALI severity. Finally, we confirmed the clinical relevance and found that IL-17 expression was elevated and associated with the disease severity in patients with ARDS. In essence, IL-17 was crucial for development of ALI, suggesting a potential application for IL-17-based therapy in clinical practice.

miR-132 inhibits lipopolysaccharide-induced inflammation in alveolar macrophages by the cholinergic anti-inflammatory pathway

OBJECTIVE

Although microRNA-132 (miR-132) has been shown to be involved in the inflammatory regulation, its role in sepsis-induced lung injury is unknown. We hypothesized that miR-132 attenuated lipopolysaccharide (LPS)-induced inflammation of alveolar macrophages by targeting acetylcholinesterase (AChE) and enhancing the acetylcholine (ACh)-mediated cholinergic anti-inflammatory response.

METHODS

The LPS-treated rat alveolar macrophage cell line NR8383 was used as the inflammatory model. To assess the effect of miR-132, alveolar macrophages were transfected with miR-132 mimic or inhibitor.

RESULTS

We found that miR-132 was upregulated in LPS-stimulated alveolar macrophages. Induction of AChE mRNA showed an inverse pattern with respect to AChE protein and activity, suggesting posttranscriptional regulation of AChE. Utilizing miR-132 mimic transfection, we found that overexpression of miR-132 enhanced the ACh-mediated cholinergic anti-inflammatory reaction by targeting AChE mRNA in LPS-treated alveolar macrophages. Blockage of miR-132 using miR-132 inhibitor reversed the Ach action upon LPS-induced release of inflammatory mediators and reduction in AchE protein/activity. Moreover, in the presence of ACh, upregulation of miR-132 suppressed LPS-induced nuclear translocation of NF-κB and production of STAT3 and phosphorylated STAT3, while downregulation of miR-132 enhanced the nuclear translocation of NF-κB.

CONCLUSION

We propose that miR-132 functions as a negative regulator of the inflammatory response in alveolar macrophages by potentiating the cholinergic anti-inflammatory pathway, and represents a potential therapeutic leverage point in modulating inflammatory responses.

Influence of in-line microfilters on systemic inflammation in adult critically ill patients: a prospective, randomized, controlled open-label trial

Background

In critically ill children, in-line microfilters may reduce the incidence of the systemic inflammatory response syndrome (SIRS), the overall complication and organ dysfunction rate. No data on the use of in-line microfilters exist in critically ill adults.

Methods

In this prospective, randomized, controlled open-label study, we evaluated the influence of in-line microfilters on systemic immune activation in 504 critically ill adults with a central venous catheter in place and an expected length of stay in the intensive care unit >24 h. Patients were randomized to have in-line microfilters placed into all intravenous lines (intervention group) or usual care (control group). The primary endpoint was the number of intensive care unit days with SIRS. Secondary endpoints were the incidence of SIRS, SIRS criteria per day, duration of invasive mechanical ventilation, intensive care unit length of stay, the incidence of acute lung injury, maximum C-reactive protein, maximum white blood cell count, incidence of new candida and/or central-line-associated bloodstream infections, incidence of new thromboembolic complications, cumulative insulin requirements and presence of hyper- or hypoglycemia.

Results

The study groups did not differ in any baseline variable. There was no difference in the number of days in the intensive care unit with SIRS between microfilter and control patients [2 (0.8–4.7) vs. 1.8 (0.7–4.4), p = 0.62]. Except for a higher incidence of SIRS in microfilter patients (99.6 vs. 96.8 %, p = 0.04), no difference between the groups was observed in any secondary outcome parameter. Results did not change when only patients with an intensive care unit length of stay of greater than 7 days were included in the analysis. The rate of adverse events was comparable between microfilter and control patients. In two patients allocated to the microfilter group, the study intervention was discontinued for technical reasons. Use of in-line microfilters was associated with additional costs.

Conclusions

The use of in-line microfilters failed to modulate systemic inflammation and clinical outcome parameters in critically ill adults.

Trial registration: Clinical Trials NCT01534390

mTOR and autophagy in regulation of acute lung injury: a review and perspective

The mammalian target of rapamycin (mTOR) is a central regulator of many major cellular processes including protein and lipid synthesis and autophagy, and is also implicated in an increasing number of pathological conditions. Emerging evidence suggests that both mTOR and autophagy are critically involved in the pathogenesis of pulmonary diseases including acute lung injury (ALI). However, the detailed mechanisms of these pathways in disease pathogenesis require further investigations. In certain cases within the same disease, the functions of mTOR and autophagy may vary from different cell types and pathogens. Here we review recent advances about the basic machinery of mTOR and autophagy, and their roles in ALI. We further discuss and propose the likelihood of cell type- and pathogen-dependent functions of these pathways in ALI pathogenesis.

Enforced expression of miR-125b attenuates LPS-induced acute lung injury

The acute respiratory distress syndrome (ARDS), a severe form of acute lung injury (ALI) in humans, is a leading cause of morbidity and mortality in critically ill patients. Despite decades of research, few therapeutic strategies for clinical ARDS have emerged. Recent evidence implicated a potential role of miR-125b in development of ALI. Here we evaluated the miR-125b-based strategy in treatment of ARDS using the murine model of lipopolysaccharide (LPS)-induced ALI. We found that up-regulation of miR-125b expression maintained the body weight and survival of ALI mice, and significantly reduced LPS-induced pulmonary inflammation as reflected by reductions in total cell and neutrophil counts, proinflammatory cytokines, as well as chemokines in BAL fluid. Further, enforced expression of miR-125b resulted in remarkable reversal of LPS-induced increases in lung permeability as assessed by reductions in total protein, albumin and IgM in BAL fluid, and ameliorated the histopathology changes of lung in LPS-induced ALI mice. Of interest, serum miR-125b expression was also decreased and inversely correlated with the disease severity in patients with ARDS. Our findings strongly demonstrated that enforced expression of miR-125b could effectively ameliorate the LPS-induced ALI, suggesting a potential application for miR-125b-based therapy to treat clinical ARDS.

Expression of IL-17A and IL-17F in lipopolysaccharide-induced acute lung injury and the counteraction of anisodamine or methylprednisolone

Th17 cytokines IL-17A and IL-17F as pro-inflammatory cytokines played an important role in triggering inflammatory responses. However, little was known about the expression of IL-17A and IL-17F in acute lung injury (ALI). Therefore, the present study investigated the expression of IL-17A and IL-17F in lipopolysaccharide (LPS)-induced ALI in rats and rat pulmonary microvascular endothelial cells (PMVEC) by enzyme-linked immunosorbant assay or reverse transcription-polymerase chains reaction. Anisodamine and methylprednisolone were also investigated as anti-inflammatory strategy in the process of LPS-induced ALI. Lung injury was evaluated by histological changes, right lung wet weight:body weight (LW/BW) ratios, and protein education and total leukocyte count of bronchoalveolar lavage fluid (BALF). Our findings showed that LPS exposure elevated the levels of leukocyte number, protein education in BALF and the ratios of LW/BW, increased the expression of IL-17A and IL-17F in the lung tissues homogenate, BALF and serum of ALI rats. Up-regulation of IL-17F expression was also observed after LPS challenge in rat PMVEC. Treatment with anisodamine or methylprednisolone significantly inhibited the increases of parameters of ALI induced by LPS, and markedly reduced the expression of IL-17A and IL-17F in rats and the IL-17F expression in PMVEC. These data suggested that IL-17A and IL-17F maybe play an important role in LPS-induced ALI via autocrine and paracrine mechanisms, and anisodamine is similar in extent to methylprednisolone that contributes to relieve LPS-induced ALI.

Mesenchymal stem cells in acute lung injury: are they ready for translational medicine?

Acute lung injury (ALI) is a severe clinical condition responsible for high mortality and the development of multiple organ dysfunctions, because of the lack of specific and effective therapies for ALI. Increasing evidence from pre-clinical studies supports preventive and therapeutic effects of mesenchymal stem cells (MSCs, also called mesenchymal stromal cells) in ALI/ARDS (acute respiratory distress syndrome). Therapeutic effects of MSCs were noticed in various delivery approaches (systemic, local, or other locations), multiple origins (bone marrow or other tissues), or different schedules of administrations (before or after the challenges). MSCs could reduce the over-production of inflammatory mediators, leucocyte infiltration, tissue injury and pulmonary failure, and produce a number of benefit factors through interaction with other cells in the process of lung tissue repair. Thus, it is necessary to establish guidelines, standard operating procedures and evaluation criteria for translating MSC-based therapies into clinical application for patients with ALI.

Prevention of LPS-induced acute lung injury in mice by progranulin

The acute respiratory distress syndrome (ARDS), a clinical complication of severe acute lung injury (ALI) in humans, is a leading cause of morbidity and mortality in critically ill patients. Despite decades of research, few therapeutic strategies for clinical ARDS have emerged. Here we carefully evaluated the effect of progranulin (PGRN) in treatment of ARDS using the murine model of lipopolysaccharide (LPS)-induced ALI. We reported that administration of PGRN maintained the body weight and survival of ALI mice. We revealed that administration of PGRN significantly reduced LPS-induced pulmonary inflammation, as reflected by reductions in total cell and neutrophil counts, proinflammatory cytokines, as well as chemokines in bronchoalveolar lavage (BAL) fluid. Furthermore, administration of PGRN resulted in remarkable reversal of LPS-induced increases in lung permeability as assessed by reductions in total protein, albumin, and IgM in BAL fluid. Consistently, we revealed a significant reduction of histopathology changes of lung in mice received PGRN treatment. Finally, we showed that PGRN/TNFR2 interaction was crucial for the protective effect of PGRN on the LPS-induced ALI. Our findings strongly demonstrated that PGRN could effectively ameliorate the LPS-induced ALI in mice, suggesting a potential application for PGRN-based therapy to treat clinical ARDS.

Synthetic LXR agonist T0901317 attenuates lipopolysaccharide-induced acute lung injury in rats

OBJECTIVE

To investigate the potential role of synthetic liver X receptors (LXRs) agonists T0901317 in lung of rats with acute lung injury induced by lipopolysaccharide (LPS).

METHODS

Rats infused with LPS served as acute lung injury (ALI) models. Specific mRNA was quantified by semi-quantitative reverse transcription polymerase (RT-PCR) and protein expression by western blotting. Inflammatory cytokine and MPO activity assays were studied by ELISA. Histopathology analysis was evaluated by hematoxylin and eosin.

RESULTS

The expressions of LXRα and LXRβ were gradually decreased after LPS challenge. T0901317 pretreatment efficiently reduced the production of TNF-α, IL-1β, and IL-6, while elevated the level of IL-10 in BALF of rats with ALI. T0901317 also decreased the number of inflammatory cells and the concentration of total proteins in the BALF. Compared with the LPS group, rats with ALI which were pretreated with T0901317 had lower pulmonary tissue MPO activity and lightened histopathologic changes of lung. Furthermore, the expressions of NF-κB and ICAM-1 were markedly reduced after T0901317 administration.

CONCLUSION

The expressions of LXRs were significantly decreased and synthetic agonist T0901317 suppresses lung inflammatory responses and lightened histopathologic changes of lung in rats with ALI. The mechanisms of this action for T0901317 may associate with the inhibition of NF-κB activation and downregulation of adhesion molecules ICAM-1 gene.

Acute pulmonary toxic effects of chlorhexidine (CHX) following an intratracheal instillation in rats

Chlorhexidine (CHX) is a cationic biguanide compound that has been widely used for disinfection of skin, mucous membranes, and medical instruments. Poisoning has been occurred occasionally due to its easy accessibility. Some fatal cases developed acute respiratory distress syndrome (ARDS) from aspiration of CHX directly into the lung. There is no preclinical information about the pulmonary toxicity of CHX available since the products of CHX are usually developed for disinfection by topical use. In this study, the acute pulmonary toxic effects of CHX following an intratracheal instillation in rats were investigated. Rats were exposed either to CHX at concentrations of 0.02% and 0.2% or to distilled water at a volume of 500 μl/kg b.w. CHX at concentration of 0.2% caused changes in hematological and biochemical values including white blood cell count (WBC), total protein (TP), albumin (ALB), lactate dehydrogenase (LDH), blood urea nitrogen (BUN) and creatinine (CRE), and induced inflammatory reactions including intra-alveolar edema and hemorrhages, as well as resulted in the target organ concentration in lungs at the level of about 1.0 μg/g and maintained for more than 1 week, when administered intratracheally in rats. The cytotoxic action of CHX might induce those detrimental reactions in rats.

Erythropoetin as a novel agent with pleiotropic effects against acute lung injury

Current pharmacotherapy for acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) is not optimal, and the biological and physiological complexity of these severe lung injury syndromes requires consideration of combined-agent treatments or agents with pleiotropic action. In this regard, exogenous erythropoietin (EPO) represents a possible candidate since a number of preclinical studies have revealed beneficial effects of EPO administration in various experimental models of ALI. Taken together, this treatment strategy is not a single mediator approach, but it rather provides protection by modulating multiple levels of early signaling pathways involved in apoptosis, inflammation, and peroxidation, potentially restoring overall homeostasis. Furthermore, EPO appears to confer vascular protection by promoting angiogenesis. However, only preliminary studies exist and more experimental and clinical studies are necessary to clarify the efficacy and potentially cytoprotective mechanisms of EPO action. In addition to the attempts to optimize the dose and timing of EPO administration, it would be of great value to minimize any potential toxicity, which is essential for EPO to fulfill its role as a potential candidate for the treatment of ALI in routine clinical practice. The present article reviews recent advances that have elucidated biological and biochemical activities of EPO that may be potentially applicable for ALI/ARDS management.

Effects of sepsis-induced acute lung injury on glycogen content in different tissues

The metabolic profile is very affected in sepsis, which is the most important cause of extrapulmonary acute lung injury (ALI-EX). The aim of the present study was to investigate whether sepsis-induced ALI-EX in mice affects the glycogen content in different tissues. This measurement could indicate performance limitations of tissues and constitute a novel biochemical aspect of ALI. ALI was induced by cecal ligation and puncture (CLP), which is a model that reproduces clinical and pathological alterations stemming from sepsis. Control group mice were sham-operated. Glycogen content (mg/g tissue) from different tissues was measured using the anthrone reagent. Glycogen content in the diaphragm (0.3 +/- 0.1) and gastrocnemius muscle (0.4 +/- 0.1) was lower in the sepsis group than the control group (0.9 +/- 0.1 and 1.1 +/- 0.2, respectively). However, there were no significant differences in glycogen content in the heart and kidney. Sepsis caused a greater thickening of the alveolar walls, more areas of atelectasis, and a greater abundance of inflammatory cells in comparison to the control group. These results demonstrate that glycogen content in sepsis-induced ALI-EX is altered in different tissues.

Basiliximab induced non-cardiogenic pulmonary edema in two pediatric renal transplant recipients

We report two cases of non-cardiogenic pulmonary edema as a complication of basiliximab induction therapy in young pediatric renal transplant patients identified following a retrospective review of all pediatric renal transplant cases performed in the National Paediatric Transplant Centre, Childrens University Hospital, Temple Street, Dublin, Ireland. Twenty-eight renal transplantations, of which five were living-related (LRD) and 23 were from deceased donors (DD), were performed in 28 children between 2003 and 2006. In six cases, transplantations were pre-emptive. Immunosuppression was induced pre-operatively using a combination of basiliximab, tacrolimus and methylprednisolone in all patients. Basiliximab induction was initiated 2 h prior to surgery in all cases and, in 26 patients, basiliximab was re-administered on post-operative day 4. Two patients, one LRD and one DD, aged 6 and 11 years, respectively, developed acute non-cardiogenic pulmonary edema within 36 h of surgery. Renal dysplasia was identified as the primary etiological factor for renal failure in both cases. Both children required assisted ventilation for between 4 and 6 days. While both grafts had primary function, the DD transplant patient subsequently developed acute tubular necrosis and was eventually lost within 3 weeks due to thrombotic microangiopathy and severe acute antibody-mediated rejection despite adequate immunosuppression. Non-cardiogenic pulmonary edema is a potentially devastating post-operative complication of basiliximab induction therapy in young pediatric patients following renal transplantation. Early recognition and appropriate supportive therapy is vital for patient and, where possible, graft survival.