Biomarkers in acute lung injury: insights into the pathogenesis of acute lung injury

Application value of P-selectin and Clara cell secretory protein 16 expression in children with severe adenovirus pneumonia

This study investigated the roles of P-selectin and Clara cell secretory protein 16 (CC16) levels in the pathogenesis of severe adenovirus (ADV) pneumonia in children and evaluated their ability to predict disease. Fifty-one children (age, 1-5 years) with ADV pneumonia who were admitted to Xiamen Children's Hospital were included in this study and divided into the mild group (24 patients) and severe group (27 patients). A control group comprising healthy children of the same age who underwent routine physical examinations during the same period (30 patients) was also included. The univariate analysis demonstrated that the levels of the white blood cell count and C-reactive protein, procalcitonin, d-dimer, and P-selectin were increased in a severe group compared with a mild group, while CC16 levels were significantly decreased (p < 0.05). The logistic regression analysis revealed that P-selectin and CC16 levels were independent risk factors for severe ADV pneumonia in children. The areas under the ROC curves suggested that P-selectin and CC16 exhibited high predictive value for severe ADV pneumonia. P-selectin values more than 898.58 pg/mL and CC16 values less than 11.355 ng/mL predicted severe ADV pneumonia. P-selectin and CC16 levels are correlated with the severity of ADV pneumonia in children.

Exploring explainable AI features in the vocal biomarkers of lung disease

This review delves into the burgeoning field of explainable artificial intelligence (XAI) in the detection and analysis of lung diseases through vocal biomarkers. Lung diseases, often elusive in their early stages, pose a significant public health challenge. Recent advancements in AI have ushered in innovative methods for early detection, yet the black-box nature of many AI models limits their clinical applicability. XAI emerges as a pivotal tool, enhancing transparency and interpretability in AI-driven diagnostics. This review synthesizes current research on the application of XAI in analyzing vocal biomarkers for lung diseases, highlighting how these techniques elucidate the connections between specific vocal features and lung pathology. We critically examine the methodologies employed, the types of lung diseases studied, and the performance of various XAI models. The potential for XAI to aid in early detection, monitor disease progression, and personalize treatment strategies in pulmonary medicine is emphasized. Furthermore, this review identifies current challenges, including data heterogeneity and model generalizability, and proposes future directions for research. By offering a comprehensive analysis of explainable AI features in the context of lung disease detection, this review aims to bridge the gap between advanced computational approaches and clinical practice, paving the way for more transparent, reliable, and effective diagnostic tools.

Targeted delivery of TGF-β mRNA to lung parenchyma using one-component ionizable amphiphilic Janus Dendrimers

Current clinical strategies for the delivery of pulmonary therapeutics to the lung are primarily targeted to the upper portions of the airways. However, targeted delivery to the lower regions of the lung is necessary for the treatment of parenchymal lung injury and disease. Here, we have developed an mRNA therapeutic for the lower lung using one-component Ionizable Amphiphilic Janus Dendrimers (IAJDs) as a delivery vehicle. We deliver an anti-inflammatory cytokine mRNA, transforming growth factor-beta (TGF-β), to produce transient protein expression in the lower regions of the lung. This study highlights IAJD's potential for precise, effective, and safe delivery of TGF-β mRNA to the lung. This delivery system offers a promising approach for targeting therapeutics to the specific tissues, a strategy necessary to fill the current clinical gap in treating parenchymal lung injury and disease.

The protective effect of karanjin against sepsis-induced acute lung injury in mice is involved in the suppression of the TLR4 pathway

Sepsis-induced acute lung injury (ALI) is a severe complication of sepsis. Karanjin, a natural flavonoid compound, has been proved to have anti-inflammatory function, but its role in sepsis-stimulated ALI is uncertain. Herein, the effect of karanjin on sepsis-stimulated ALI was investigated. We built a mouse model of lipopolysaccharide (LPS)-stimulated ALI. The histopathological morphology of lung tissues was scrutinized by hematoxylin-eosin (H&E) staining. The lung injury score and lung wet/dry weight ratio were detected. The myeloperoxidase (MPO) activity and malondialdehyde (MDA) content were scrutinized by commercial kits. Murine alveolar lung epithelial (MLE-12) cells were treated with LPS to mimic a cellular model of ALI. The cell viability was scrutinized by the CCK-8 assay. The contents of proinflammatory cytokines were scrutinized by qRT-PCR and ELISA. The TLR4 and MyD88 contents were scrutinized by qRT-PCR and western blotting. Results showed that karanjin alleviated LPS-stimulated ALI in mice by inhibiting lung tissue lesions, edema, and oxidative stress. Moreover, karanjin inhibited LPS-stimulated inflammation and TLR4 pathway activation in mice. However, treatment with GSK1795091, an agonist of TLR4, attenuated the effects of karanjin on LPS-induced ALI. Furthermore, karanjin repressed LPS-stimulated inflammatory response and TLR4 pathway activation in MLE-12 cells. Overexpression of TLR4 attenuated karanjin effects on LPS-stimulated inflammatory responses in MLE-12 cells. In conclusion, karanjin repressed sepsis-stimulated ALI in mice by suppressing the TLR4 pathway.

Bear Bile Powder Ameliorates LPS-Induced Acute Lung Injury by Inhibiting CD14 Pathway and Improving Intestinal Flora: Exploration of "Fei (Lung)-Dachang (Large Intestine) Interaction"

OBJECTIVE

To explore the effect of bear bile powder (BBP) on acute lung injury (ALI) and the underlying mechanism.

METHODS

The chemical constituents of BBP were analyzed by ultra-high-pressure liquid chromatography-mass spectrometry (UPLC-MS). After 7 days of adaptive feeding, 50 mice were randomly divided into 5 groups by a random number table (n=10): normal control (NC), lipopolysaccharide (LPS), dexamethasone (Dex), low-, and high-dose BBP groups. The dosing cycle was 9 days. On the 12th and 14th days, 20 µL of Staphylococcus aureus solution (bacterial concentration of 1 × 10-7 CFU/mL) was given by nasal drip after 1 h of intragastric administration, and the mice in the NC group was given the same dose of phosphated buffered saline (PBS) solution. On the 16th day, after 1 h intragastric administration, 100 µL of LPS solution (1 mg/mL) was given by tracheal intubation, and the same dose of PBS solution was given to the NC group. Lung tissue was obtained to measure the myeloperoxidase (MPO) activity, the lung wet/dry weight ratio and expressions of CD14 and other related proteins. The lower lobe of the right lung was obtained for pathological examination. The concentrations of inflammatory cytokines including interleukin (IL)-6, tumour necrosis factor α (TNF-α ) and IL-1β in the bronchoalveolar lavage fluid (BALF) were detected by enzyme linked immunosorbent assay, and the number of neutrophils was counted. The colonic contents of the mice were analyzed by 16 sRNA technique and the contents of short-chain fatty acids (SCFAs) were measured by gas chromatograph-mass spectrometer (GC-MS).

RESULTS

UPLC-MS revealed that the chemical components of BBP samples were mainly tauroursodeoxycholic acid and taurochenodeoxycholic acid sodium salt. BBP reduced the activity of MPO, concentrations of inflammatory cytokines, and inhibited the expression of CD14 protein, thus suppressing the activation of NF-κB pathway (P<0.05). The lung histopathological results indicated that BBP significantly reduced the degree of neutrophil infiltration, cell shedding, necrosis, and alveolar cavity depression. Moreover, BBP effectively regulated the composition of the intestinal microflora and increased the production of SCFAs, which contributed to its treatment effect (P<0.05).

CONCLUSIONS

BBP alleviates lung injury in ALI mouse through inhibiting activation of NF-κB pathway and decreasing expression of CD14 protein. BBP may promote recovery of ALI by improving the structure of intestinal flora and enhancing metabolic function of intestinal flora.

Endothelial cell dynamics in sepsis-induced acute lung injury and acute respiratory distress syndrome: pathogenesis and therapeutic implications

Sepsis, a prevalent critical condition in clinics, continues to be the leading cause of death from infections and a global healthcare issue. Among the organs susceptible to the harmful effects of sepsis, the lungs are notably the most frequently affected. Consequently, patients with sepsis are predisposed to developing acute lung injury (ALI), and in severe cases, acute respiratory distress syndrome (ARDS). Nevertheless, the precise mechanisms associated with the onset of ALI/ARDS remain elusive. In recent years, there has been a growing emphasis on the role of endothelial cells (ECs), a cell type integral to lung barrier function, and their interactions with various stromal cells in sepsis-induced ALI/ARDS. In this comprehensive review, we summarize the involvement of endothelial cells and their intricate interplay with immune cells and stromal cells, including pulmonary epithelial cells and fibroblasts, in the pathogenesis of sepsis-induced ALI/ARDS, with particular emphasis placed on discussing the several pivotal pathways implicated in this process. Furthermore, we discuss the potential therapeutic interventions for modulating the functions of endothelial cells, their interactions with immune cells and stromal cells, and relevant pathways associated with ALI/ARDS to present a potential therapeutic strategy for managing sepsis and sepsis-induced ALI/ARDS.

Discovery of a doublecortin-like kinase 1 inhibitor to prevent inflammatory responses in acute lung injury

Doublecortin-like kinase 1 (DCLK1) is a microtubule-associated protein kinase involved in neurogenesis and human cancer. Recent studies have revealed a novel functional role for DCLK1 in inflammatory signaling, thus positioning it as a novel target kinase for respiratory inflammatory disease treatment. In this study, we designed and synthesized a series of NVP-TAE684-based derivatives as novel anti-inflammatory agents targeting DCLK1. Bio-layer interferometry binding screening and kinase assays of the NVP-TAE684 derivatives led to the discovery of an effective DCLK1 inhibitor (a24), with an IC50 of 179.7 nM. Compound a24 effectively inhibited lipopolysaccharide (LPS)-induced inflammation in macrophages with higher potency than the lead compound. Mechanistically, compound a24 inhibited LPS-induced inflammation by inhibiting DCLK1-mediated IKKβ phosphorylation. Furthermore, compound a24 showed in vivo anti-inflammatory activity in an LPS-challenged acute lung injury model. These findings suggest that compound a24 may serve as a novel candidate for the development of DCLK1 inhibitors and a potential therapeutic agent for the treatment of inflammatory diseases.

In vitro inflammation and toxicity assessment of pre- and post-incinerated organomodified nanoclays to macrophages using high-throughput screening approaches

BACKGROUND

Organomodified nanoclays (ONC), two-dimensional montmorillonite with organic coatings, are increasingly used to improve nanocomposite properties. However, little is known about pulmonary health risks along the nanoclay life cycle even with increased evidence of airborne particulate exposures in occupational environments. Recently, oropharyngeal aspiration exposure to pre- and post-incinerated ONC in mice caused low grade, persistent lung inflammation with a pro-fibrotic signaling response with unknown mode(s) of action. We hypothesized that the organic coating presence and incineration status of nanoclays determine the inflammatory cytokine secretary profile and cytotoxic response of macrophages. To test this hypothesis differentiated human macrophages (THP-1) were acutely exposed (0-20 µg/cm2) to pristine, uncoated nanoclay (CloisNa), an ONC (Clois30B), their incinerated byproducts (I-CloisNa and I-Clois30B), and crystalline silica (CS) followed by cytotoxicity and inflammatory endpoints. Macrophages were co-exposed to lipopolysaccharide (LPS) or LPS-free medium to assess the role of priming the NF-κB pathway in macrophage response to nanoclay treatment. Data were compared to inflammatory responses in male C57Bl/6J mice following 30 and 300 µg/mouse aspiration exposure to the same particles.

RESULTS

In LPS-free media, CloisNa exposure caused mitochondrial depolarization while Clois30B exposure caused reduced macrophage viability, greater cytotoxicity, and significant damage-associated molecular patterns (IL-1α and ATP) release compared to CloisNa and unexposed controls. LPS priming with low CloisNa doses caused elevated cathepsin B/Caspage-1/IL-1β release while higher doses resulted in apoptosis. Clois30B exposure caused dose-dependent THP-1 cell pyroptosis evidenced by Cathepsin B and IL-1β release and Gasdermin D cleavage. Incineration ablated the cytotoxic and inflammatory effects of Clois30B while I-CloisNa still retained some mild inflammatory potential. Comparative analyses suggested that in vitro macrophage cell viability, inflammasome endpoints, and pro-inflammatory cytokine profiles significantly correlated to mouse bronchioalveolar lavage inflammation metrics including inflammatory cell recruitment.

CONCLUSIONS

Presence of organic coating and incineration status influenced inflammatory and cytotoxic responses following exposure to human macrophages. Clois30B, with a quaternary ammonium tallow coating, induced a robust cell membrane damage and pyroptosis effect which was eliminated after incineration. Conversely, incinerated nanoclay exposure primarily caused elevated inflammatory cytokine release from THP-1 cells. Collectively, pre-incinerated nanoclay displayed interaction with macrophage membrane components (molecular initiating event), increased pro-inflammatory mediators, and increased inflammatory cell recruitment (two key events) in the lung fibrosis adverse outcome pathway.

Incidence and risk factors of postoperative pulmonary complications after oral cancer surgery with free flap reconstruction: A single center study

BACKGROUND

Postoperative pulmonary complications (PPCs) increase the risk of morbidity and mortality in patients who underwent oral cancer surgery with free flap reconstruction. The association between PPC and preoperative risk factors has been investigated; however, reports on intraoperative factors are limited. Therefore, we investigated PPC incidence and its associated preoperative and intraoperative risk factors in these patients.

METHODS

We retrospectively analyzed medical records of patients who underwent free flap reconstruction between 2009 and 2019. PPC was defined as presence of atelectasis, pneumonia, and respiratory failure based on radiological confirmation and clinical symptoms during hospitalization. Mortality, hospital stay, preoperative factors (including age and tumor stages), American Society of Anesthesiologists (ASA) classification, and intraoperative factors (including intraoperative fluids and medications) were recorded.

RESULTS

PPC incidence among the 993 patients included in this study was 25.8% (256 patients). Six patients with PPCs died; death was not observed among patients without PPCs (p < 0.001). Patients with PPCs had longer hospitalization than those without PPCs (30.3 vs 23.3 days; p < 0.001). Tumor stage (stage I: reference; stage II [OR]: 3.3, p = 0.019; stage III: 4.4, p = 0.002; stage IV: 4.8, p = 0.002), age (OR: 1.0; p < 0.001), and ASA grade >2 (OR: 1.4; p = 0.020) were independent risk factors of PPC; using labetalol was a borderline significant factor (OR: 1.4; p = 0.050).

CONCLUSION

The PPC incidence was 25.8% in patients undergoing oral cancer surgery with free flap reconstruction. Tumor stage, age, and ASA >2 were risk factors of developing PPC.

The Protective Role of Mitochondria-Associated Endoplasmic Reticulum Membrane (MAM) Protein Sigma-1 Receptor in Regulating Endothelial Inflammation and Permeability Associated with Acute Lung Injury

Earlier studies from our lab identified endoplasmic reticulum (ER) chaperone BiP/GRP78, an important component of MAM, to be a novel determinant of endothelial cell (EC) dysfunction associated with acute lung injury (ALI). Sigma1R (Sig1R) is another unique ER receptor chaperone that has been identified to associate with BiP/GRP78 at the MAM and is known to be a pluripotent modulator of cellular homeostasis. However, it is unclear if Sig1R also plays a role in regulating the EC inflammation and permeability associated with ALI. Our data using human pulmonary artery endothelial cells (HPAECs) showed that siRNA-mediated knockdown of Sig1R potentiated LPS-induced the expression of proinflammatory molecules ICAM-1, VCAM-1 and IL-8. Consistent with this, Sig1R agonist, PRE-084, known to activate Sig1R by inducing its dissociation from BiP/GRP78, blunted the above response. Notably, PRE-084 failed to blunt LPS-induced inflammatory responses in Sig1R-depleted cells, confirming that the effect of PRE-084 is driven by Sig1R. Furthermore, Sig1R antagonist, NE-100, known to inactivate Sig1R by blocking its dissociation from BiP/GRP78, failed to block LPS-induced inflammatory responses, establishing that dissociation from BiP/GRP78 is required for Sig1R to exert its anti-inflammatory action. Unlike Sig1R, the siRNA-mediated knockdown or Subtilase AB-mediated inactivation of BiP/GRP78 protected against LPS-induced EC inflammation. Interestingly, the protective effect of BiP/GRP78 knockdown or inactivation was abolished in cells that were depleted of Sig1R, confirming that BiP/GRP78 knockdown/inactivation-mediated suppression of EC inflammation is mediated via Sig1R. In view of these findings, we determined the in vivo relevance of Sig1R in a mouse model of sepsis-induced ALI. The intraperitoneal injection of PRE-084 mitigated sepsis-induced ALI, as evidenced by a decrease in ICAM-1, IL-6 levels, lung PMN infiltration, and lung vascular leakage. Together, these data evidence a protective role of Sig1R against endothelial dysfunction associated with ALI and identify it as a viable target in terms of controlling ALI in sepsis.

Anti-inflammatory effect and component analysis of Chaihu Qingwen granules

ETHNOPHARMACOLOGICAL RELEVANCE

As prevalent acute respiratory condition in clinical practice, acute lung injury has a quick start and severe symptoms which can harm patients physically. Chaihu Qingwen granules (CHQW) is a classic formula for the treatment of respiratory diseases. Clinical observation shows that CHQW has good efficacy in treating colds, coughs, and fevers.

AIM OF THE STUDY

The aim of this study was to investigate the anti-inflammatory effect of CHQW on lipopolysaccharide (LPS)-induced acute lung injury (ALI) model in rats and to explore its potential mechanism, as well as to clarify its substance composition.

MATERIALS AND METHODS

Male SD rats were randomly divided into the blank group, the model group, the ibuprofen group, the Lianhua Qingwen capsule group and the CHQW group (2, 4 and 8 g/kg, respectively). The LPS-induced acute lung injury (ALI) model in rats was established after pre-administration. The histopathological changes in the lung and the levels of inflammatory factors in bronchoalveolar lavage fluid (BALF) and serum of ALI rats were observed. The inflammation-related proteins toll-like receptor 4 (TLR4), inhibitory kappa B alpha (IκBα), phospho-IκBα (p-IκBα), nuclear-factor-kappa B (NF-κB), and NLR family pyrin domain containing 3(NLRP3) expression levels were measured by western blotting analysis and immunohistochemical analysis. The chemical composition of CHQW was identified by liquid chromatography-quadrupole-time of flight-mass spectrometry (LC-Q-TOF-MS).

RESULTS

CHQW significantly ameliorated lung tissue pathological injury in LPS-induced ALI rats and decreased the release of inflammatory cytokines (interleukin-1β, interleukin-17 and tumor necrosis factor-α) in BALF and serum. In addition, CHQW decreased the expression of TLR4, p-IκBα and NF-κB proteins, increased the level of IκBα, regulated the TLR4/NF-κB signaling pathway, and inhibited the activation of NLRP3. The chemical components of CHQW were analyzed by LC-Q-TOF-MS, and a total of 48 components were identified by combining information from the literature, mainly flavonoids, organic acids, lignans, iridoids and phenylethanoid glycosides.

CONCLUSION

The results of this study showed that the pretreatment of CHQW had a strong protective effect on LPS-induced ALI in rats, reducing lung tissue lesions and decreasing inflammatory cytokines released in BALF and serum. The protective mechanism of CHQW may be related to the inhibition of the TLR4/NF-κB signaling pathway and NLRP3 activation. The main active ingredients of CHQW are flavonoids, organic acids, lignans, iridoids and phenylethanoid glycosides.

Thrombin worsens extravascular lung water and outcomes of septic patients with acute respiratory distress syndrome: A case control study

Endothelial cell (EC) activation may increase systemic vascular permeability, causing extravascular lung water (EVLW) in sepsis with acute respiratory distress syndrome (ARDS). However, the correlation between thrombin and EVLW in sepsis and ARDS has not yet been addressed. Patients with sepsis and ARDS were prospectively enrolled between 2014 and 2016, and EVLW and serum thrombin levels on days 1 and 3 were measured and compared between surviving and non-surviving patients. Additionally, morphological changes in human umbilical vein endothelial cells (HUVECs) in the serum of patients with high and low EVLW were evaluated. The levels of EVLW, endothelial cells, and thrombin may positively correlate with the survival of patients with severe sepsis and ARDS. Twenty-seven patients were enrolled, and baseline characteristics, including age, sex, Acute Physiology and Chronic Health Evaluation (APACHE) II, prior 24-h fluid balance, body mass index, and shock status, were similar between survivors and non-survivors; however, day 1 EVLW was higher in non-survivors (27.5 ± 8.4 vs 22 ± 6.5 mL/kg, P = .047). EVLW of survivors improved from day 1 to day 3 (22 ± 6.5 vs 11 ± 3.8 mL/kg, P < .001), but did not improve in non-survivors (27.5 ± 8.4 vs 28 ± 6.7 mL/kg, P = .086), which means that patients had significantly lower EVLW on day 3 than on day 1. Thrombin levels of survivors significantly improved (1.03 ± 0.55 vs 0.87 ± 0.25 U/mL, P = .04) but did not improve in non-survivors (1.97 ± 0.75 vs 2.2 ± 0.75 U/mL, P = .08) from day 1 to day 3. EVLW and thrombin levels were positively correlated (r2 = 0.71, P < .0001). In vitro, the morphology and junctions of HUVECs changed when the serum from patients with high EVLW was added. The intercellular distances among the control, high EVLW, and low EVLW groups were 5.25 ± 1.22, 21.33 ± 2.15, and 11.17 ± 1.64 µm, respectively (P < .05).

Ayurveda-based phytochemical composition attenuates lung inflammation and precipitates pharmacokinetic interaction with favipiravir: an in vivo investigation using disease-state of acute lung injury

Acute respiratory distress syndrome (ARDS) is a critical form of acute lung injury (ALI). Here, we investigated the effect of a defined combination of ten pure phytochemicals in equal proportions of weight (NPM) from plants, recommended by Ayurveda for any protective action against lipopolysaccharide (LPS)-induced ALI. Results indicate that NPM markedly improved protein and neutrophil contents, myeloperoxidase and hydroxyproline levels, oxidative stress markers (glutathione and malonaldehyde), inflammatory cytokines, and genes (IL-6, TNF-α, TGF-β, and NF-κB/IκBα) in BALF/lung tissue. The histopathological examination of the lung revealed the shielding effect of NPM against ALI. NPM exhibited a protective effect on the lung by reducing oxidative stress and inhibiting inflammation. A substantial drop in favipiravir's oral exposure was observed in ALI-state compared to normal-state, but oral exposure upon NPM treatment in ALI-state followed similar behaviour of favipiravir alike normal-state without NPM treatment. Overall, results offer potential insight into Ayurvedic recommendations for immunity boosting during ALI situations.

Exogenous IL-10 posttreatment along with TLR4 and TNFR1 blockade improves tissue antioxidant status by modulating sepsis-induced macrophage polarization

Multi-organ dysfunction is one of the major reasons behind the high mortality of sepsis throughout the world. With the pathophysiology of sepsis remaining largely unknown, the uncontrolled reactive oxygen species (ROS) production along with the decreased antioxidants contributes to the progression toward septic shock. Being the effector cells of the innate immunity system, macrophages secrete both pro-inflammatory and anti-inflammatory mediators during inflammation. Lipopolysaccharide (LPS) binding to toll-like receptor 4 (TLR4) releases TNF-α, which initiates pro-inflammatory events through tumor necrosis factor receptor 1 (TNFR1) signaling. However, it is counteracted by the anti-inflammatory interleukin 10 (IL-10) causing decreased oxidative stress. Our study thus aimed to assess the effects of exogenous IL-10 treatment post-neutralization of TLR4 and TNFR1 (by anti-TLR4 antibody and anti-TNFR1 antibody, respectively) in an in vivo murine model of LPS-sepsis. We have also examined the tissue-specific antioxidant status in the spleen, liver, and lungs along with the serum cytokine levels in adult male Swiss albino mice to determine the functional association with the disease. The results showed that administration of recombinant IL-10 post-neutralization of the receptors was beneficial in shifting the macrophage polarization to the anti-inflammatory M2 phenotype. IL-10 treatment significantly downregulated the free radicals production resulting in diminished lipid peroxidase (LPO) levels. The increased antioxidant activities of superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GRX ) conferred protection against LPS-induced sepsis. Western blot data further confirmed diminished expressions of TLR4 and TNFR1 along with suppressed stress-activated protein kinases/Jun amino-terminal kinases (SAPK/JNK) and increased SOD and CAT expressions, which altogether indicated that neutralization of TLR4 and TNFR1 along with IL-10 posttreatment might be a potential therapeutic measure for the treatment of sepsis.

Integrating network pharmacology and pharmacological evaluation to reveal the therapeutic effects and potential mechanism of S-allylmercapto-N-acetylcysteine on acute respiratory distress syndrome

In this research, we sought to examine the effectiveness of S-allylmercapto-N-acetylcysteine (ASSNAC) on LPS-provoked acute respiratory distress syndrome (ARDS) and its potential mechanism based on network pharmacology. To incorporate the effective targets of ASSNAC against ARDS, we firstly searched DisGeNET, TTD, GeneCards and OMIM databases. Then we used String database and Cytoscape program to create the protein-protein interaction network. Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis both identified the potential pathways connected to genes. Cytoscape software was used to build the network of drug-targets-pathways and the SwissDock platform was applied to dock the molecule of ASSNAC with the key disease targets. Correspondingly, an ARDS model was established by instillation of LPS in mice to confirm the underlying action mechanism of ASSNAC on ARDS as indicated by the network pharmacology analysis. Results exhibited that 27 overlapping targets, including TLR4, ICAM1, HIF1A, MAPK1, NFKB1, and others, were filtered out. The in vivo experiments showed that ASSNAC alleviated LPS-induced lung injury by downregulating levels of pro-inflammatory mediators and lung dry-wet ratio. Also, ASSNAC attenuated oxidative stress evoked by LPS via diminishing MDA production and SOD consumption as well as upregulating HO-1 level through Nrf2 activation. Results from western blot, quantitative real-time PCR and immunohistochemistry suggested that ASSNAC developed its therapeutic effects by regulating TLR4/MyD88/NF-κB signaling pathway. In conclusion, our research presented the efficacy of ASSNAC against ARDS. Furthermore, the mechanism of ASSNAC on ARDS was clarified by combining network pharmacology prediction with experimental confirmation.

Sulfasalazine prevents lung injury due to intra-abdominal sepsis in rats: possible role of Nrf2 and angiopoietin-2

This study aimed to investigate the effect of sulfasalazine in preventing and treating intra-abdominal sepsis-induced acute respiratory distress syndrome (ARDS) in a rat model. Forty male Wistar albino rats were used. The rats were randomly divided into four equal groups, and sepsis was induced in 30 rats by intraperitoneal administration of a fecal saline solution prepared from rat feces. Group 1: normal control (n=10) [non-surgical], Group 2: fecal intraperitoneal injection (FIP) (n=10) [untreated septic group], Group 3: FIP+saline (placebo) (n=10) [saline administered intraperitoneally], Group 4 (n=10): FIP+sulfasalazine [250 mg/kg per day administered intraperitoneally]. Computed tomography was performed and blood samples were collected for biochemical and blood gas analysis. The lungs were removed for histopathological studies. Statistically significant reductions in interleukin (IL)-6, IL1-β, tumor necrosis factor (TNF)-α, malondialdehyde (MDA), and angiopoietin-2 (ANG-2) levels were observed in the sulfasalazine group compared to the FIP+saline group (P<0.001). Nrf2 levels were significantly higher in the sulfasalazine-treated group than in the FIP and FIP+saline groups (P<0.01). Lung tissue scores were significantly reduced in the sulfasalazine group compared to the other sepsis groups. The Hounsfield unit (HU) value was significantly lower in the sulfasalazine group than in the FIP+saline group (P<0.001). PaO2 values were significantly higher in the sulfasalazine-treated group than in the FIP+saline-treated group (P<0.05). Sulfasalazine was shown to be effective in preventing and treating ARDS.

Shiwei Qingwen decoction regulates TLR4/NF-κB signaling pathway and NLRP3 inflammasome to reduce inflammatory response in lipopolysaccharide -induced acute lung injury

ETHNOPHARMACOLOGICAL RELEVANCE

Shiwei Qingwen decoction (SWQ), a Chinese herbal formula based on the classic traditional Chinese medicine prescription Yu Ping Feng San, has shown efficacy in preventing and treating early pneumonia with good clinical outcomes. However, its underlying mechanism is yet unclear.

AIM OF THE STUDY

To clarify the preventive and therapeutic effects of SWQ on lipopolysaccharide (LPS)-induced acute lung injury (ALI) and explore the underlying mechanism by which SWQ influences pneumonia.

MATERIALS AND METHODS

First, the chemical composition of SWQ was preliminarily determined by high performance liquid chromatography (HPLC), and the impact of SWQ (3.27, 6.55, and 13.1 g/kg) was assessed in the LPS-induced ALI rat model. Next, its inflammatory pathway was determined via network pharmacology. Finally, the molecular mechanism of SWQ was validated using a rat ALI model and a THP-1 cell inflammation model.

RESULTS

HPLC identified chlorogenic acid, prime-O-glucosylcimifugin, calycosin, and 5-O-methylaminoside in the chemical profile of SWQ. In the ALI model, SWQ alleviated ALI by reducing lung wet/dry weight ratio (W/D) and preventing histopathological damage to the lungs. At the same time, SWQ decreased penetration of inflammatory mediators by upregulating AQP1 and AQP5 and endothelial nitric oxide synthase (eNOS). Pretreatment with SWQ downregulated white blood cells and neutrophils count in BALF and suppressed LPS-induced expression levels of MPO, NE, and pro-inflammatory factors (TNF-α, IL-1β, IL-6, and iNOS). Network pharmacology showed that SWQ was associated with TLR4/NF-κB inflammation pathway. Moreover, pretreatment with SWQ reduced the expression level of TLR4/NF-κB signaling pathway-associated proteins (TLR4, Myd88, p-IκB, and p-p65) and NLRP3 inflammasome (NLRP3, ASC, caspase-1, and cleaved-IL-1β) in vivo and vitro.

CONCLUSIONS

The present study demonstrates that SWQ can reduce inflammation in ALI by inhibiting TLR4/NF-κB and NLRP3 inflammasome activation.

Sensitization of GSH synthesis by curcumin curtails acrolein-induced alveolar epithelial apoptosis via Keap1 cysteine conjugation: A randomized controlled trial and experimental animal model of pneumonitis

INTRODUCTION

Epidemiological studies have reported an association between exposures to ambient air pollution and respiratory diseases, including chronic obstructive pulmonary disease (COPD). Pneumonitis is a critical driving factor of COPD and exposure to air pollutants (e.g., acrolein) is associated with increased incidence of pneumonitis.

OBJECTIVES

Currently available anti-inflammatory therapies provide little benefit against respiratory diseases. To this end, we investigated the preventive role of curcumin against air pollutant-associated pneumonitis and its underlying mechanism.

METHODS

A total of 40 subjects was recruited from Chengdu, China which is among the top three cities in terms of respiratory mortality related to air pollution. The participants were randomly provided either placebo or curcumin supplements for 2 weeks and blood samples were collected at the baseline and at the end of the intervention to monitor systemic markers. In our follow up mechanistic study, C57BL/6 mice (n = 40) were randomly allocated into 4 groups: Control group (saline + no acrolein), Curcumin only group (curcumin + no acrolein), Acrolein only group (saline + acrolein), and Acrolein + Curcumin group (curcumin + acrolein). Curcumin was orally administered at 100 mg/kg body weight once a day for 10 days, and then the mice were subjected to nasal instillation of acrolein (5 mg/kg body weight). Twelve hours after single acrolein exposure, all mice were euthanized.

RESULTS

Curcumin supplementation, with no noticeable adverse responses, reduced circulating pro-inflammatory cytokines in association with clinical pneumonitis as positive predictive while improving those of anti-inflammatory cytokines. In the pre-clinical study, curcumin reduced pneumonitis manifestations by suppression of intrinsic and extrinsic apoptotic signaling, which is attributed to enhanced redox sensing of Nrf2 and thus sensitized synthesis and restoration of GSH, at least in part, through curcumin-Keap1 conjugation.

CONCLUSIONS

Our study collectively suggests that curcumin could provide an effective preventive measure against air pollutant-enhanced pneumonitis and thus COPD.

Circulating Pulmonary-Originated Epithelial Biomarkers for Acute Respiratory Distress Syndrome: A Systematic Review and Meta-Analysis

Previous studies have found several biomarkers for acute respiratory distress syndrome (ARDS), but the accuracy of most biomarkers is still in doubt due to the occurrence of other comorbidities. In this systematic review and meta-analysis, we aimed to explore ideal ARDS biomarkers which can reflect pathophysiology features precisely and better identify at-risk patients and predict mortality. Web of Science, PubMed, Embase, OVID, and the Cochrane Library were systematically searched for studies assessing the reliability of pulmonary-originated epithelial proteins in ARDS. A total of 32 studies appeared eligible for meta-analysis, including 2654 ARDS/ALI patients in this study. In the at-risk patients' identification group, the highest pooled effect size was observed in Krebs von den Lungren-6 (KL-6) (SMD: 1.17 [95% CI: 0.55, 1.79]), followed by club cell proteins 16 (CC16) (SMD: 0.74 [95% CI: 0.01, 1.46]), and surfactant proteins-D (SP-D) (SMD: 0.71 [95% CI: 0.57, 0.84]). For the mortality prediction group, CC16 exhibited the largest effect size with SMD of 0.92 (95% CI: 0.42, 1.43). Meanwhile, the summary receiver operating characteristic (SROC) of CC16 for ARDS diagnosis reached an AUC of 0.80 (95% CI: 0.76, 0.83). In conclusion, this study provides a ranking system for pulmonary-originated epithelial biomarkers according to their association with distinguishing at-risk patients and predicting mortality. In addition, the study provides evidence for the advantage of biomarkers over traditional diagnostic criteria. The performance of biomarkers may help to clinically improve the ARDS diagnosis and mortality prediction.

Superior protective effects of PGE2 priming mesenchymal stem cells against LPS-induced acute lung injury (ALI) through macrophage immunomodulation

BACKGROUND

Mesenchymal stem cells (MSCs) have demonstrated remarkable therapeutic promise for acute lung injury (ALI) and its severe form, acute respiratory distress syndrome (ARDS). MSC secretomes contain various immunoregulatory mediators that modulate both innate and adaptive immune responses. Priming MSCs has been widely considered to boost their therapeutic efficacy for a variety of diseases. Prostaglandin E2 (PGE2) plays a vital role in physiological processes that mediate the regeneration of injured organs.

METHODS

This work utilized PGE2 to prime MSCs and investigated their therapeutic potential in ALI models. MSCs were obtained from human placental tissue. MSCs were transduced with firefly luciferase (Fluc)/eGFP fusion protein for real-time monitoring of MSC migration. Comprehensive genomic analyses explored the therapeutic effects and molecular mechanisms of PGE2-primed MSCs in LPS-induced ALI models.

RESULTS

Our results demonstrated that PGE2-MSCs effectively ameliorated lung injury and decreased total cell numbers, neutrophils, macrophages, and protein levels in bronchoalveolar lavage fluid (BALF). Meanwhile, treating ALI mice with PGE2-MSCs dramatically reduced histopathological changes and proinflammatory cytokines while increasing anti-inflammatory cytokines. Furthermore, our findings supported that PGE2 priming improved the therapeutic efficacy of MSCs through M2 macrophage polarization.

CONCLUSION

PGE2-MSC therapy significantly reduced the severity of LPS-induced ALI in mice by modulating macrophage polarization and cytokine production. This strategy boosts the therapeutic efficacy of MSCs in cell-based ALI therapy.

AA, Kudriaeva AA, Bugrimov DY, Krasnorutskaya ON, Murashev AN. Derinat® has an immunomodulatory and anti-inflammatory effect on the model of acute lung injury in male SD rats

To simulate acute lung injury (ALI) in SD male rats they we administered intratracheally with lipopolysaccharide (LPS) followed by hyperventilation of the lungs (HVL), which lead to functional changes in the respiratory system and an increase in the blood serum concentration of inflammatory cytokines. LPS + HVL after 4 h lead to pronounced histological signs of lung damage. We have studied the effectiveness of Derinat^® when administered intramuscularly at dose of 7.5 mg/kg for 8 days in the ALI model. Derinat^® administration lead to an increase in the concentration of most of the studied cytokines in a day. In the ALI model the administration of Derinat^® returned the concentration of cytokines to its original values already 48 h after LPS + HVL, and also normalized the parameters of pulmonary respiration in comparison with animals without treatment. By the eighth day after LPS + HVL, respiratory parameters and cytokine levels, as well as biochemical and hematological parameters did not differ between groups, while histological signs of residual effects of lung damage were found in all animals, and were more pronounced in Derinat^® group, which may indicate stimulation of the local immune response. Thus, the administration of Derinat^® stimulates the immune response, has a pronounced protective effect against cytokinemia and respiratory failure caused by ALI, has immunomodulatory effect, and also stimulates a local immune response in lung tissues. Thus, Derinat^® is a promising treatment for ALI.

Selected Phytochemicals to Combat Lungs Injury: Natural Care

The human has two lungs responsible for respiration and drug metabolism. Severe lung infection caused by bacteria, mycobacteria, viruses, fungi, and parasites may lead to lungs injury. Smoking and tobacco consumption may also produce lungs injury. Inflammatory and pain mediators are secreted by alveolar macrophages. The inflammatory mediators, such as cytokines, interleukin (IL)-1, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF)-α, neutrophils, and fibroblasts are accumulated in the alveoli sac, which becomes infected. It may lead to hypoxia followed by severe pulmonary congestion and the death of the patient. There is an urgent need for the treatment of artificial respiration and ventilation. However, the situation may be the worst for patients suffering from lung cancer, pulmonary tuberculosis, and acute pneumonia caused by acute respiratory distress syndrome (ARDS). Re-urgency has been happening in the case of coronavirus disease of 2019 (COVID-19) patients. Therefore, it is needed to protect the lungs with the intake of natural phytomedicines. In the present review, several selected phyto components having the potential role in lung injury therapy have been discussed. Regular intake of natural vegetables and fruits bearing these constituents may save the lungs even in the dangerous attack of SARS-CoV-2 in lung cancer, pulmonary TB, and pneumatic patients.

Pulmonary Fibrosis as a Result of Acute Lung Inflammation: Molecular Mechanisms, Relevant In Vivo Models, Prognostic and Therapeutic Approaches

Pulmonary fibrosis is a chronic progressive lung disease that steadily leads to lung architecture disruption and respiratory failure. The development of pulmonary fibrosis is mostly the result of previous acute lung inflammation, caused by a wide variety of etiological factors, not resolved over time and causing the deposition of fibrotic tissue in the lungs. Despite a long history of study and good coverage of the problem in the scientific literature, the effective therapeutic approaches for pulmonary fibrosis treatment are currently lacking. Thus, the study of the molecular mechanisms underlying the transition from acute lung inflammation to pulmonary fibrosis, and the search for new molecular markers and promising therapeutic targets to prevent pulmonary fibrosis development, remain highly relevant tasks. This review focuses on the etiology, pathogenesis, morphological characteristics and outcomes of acute lung inflammation as a precursor of pulmonary fibrosis; the pathomorphological changes in the lungs during fibrosis development; the known molecular mechanisms and key players of the signaling pathways mediating acute lung inflammation and pulmonary fibrosis, as well as the characteristics of the most common in vivo models of these processes. Moreover, the prognostic markers of acute lung injury severity and pulmonary fibrosis development as well as approved and potential therapeutic approaches suppressing the transition from acute lung inflammation to fibrosis are discussed.

Targeting caveolae to pump bispecific antibody to TGF-β into diseased lungs enables ultra-low dose therapeutic efficacy

The long-sought-after "magic bullet" in systemic therapy remains unrealized for disease targets existing inside most tissues, theoretically because vascular endothelium impedes passive tissue entry and full target engagement. We engineered the first "dual precision" bispecific antibody with one arm pair to precisely bind to lung endothelium and drive active delivery and the other to precisely block TGF-β effector function inside lung tissue. Targeting caveolae for transendothelial pumping proved essential for delivering most of the injected intravenous dose precisely into lungs within one hour and for enhancing therapeutic potency by >1000-fold in a rat pneumonitis model. Ultra-low doses (μg/kg) inhibited inflammatory cell infiltration, edema, lung tissue damage, disease biomarker expression and TGF-β signaling. The prodigious benefit of active vs passive transvascular delivery of a precision therapeutic unveils a new promising drug design, delivery and therapy paradigm ripe for expansion and clinical testing.

Systemic interleukin-6 inhibition ameliorates acute neuropsychiatric phenotypes in a murine model of acute lung injury

Acute neuropsychiatric impairments occur in over 70% of patients with acute lung injury. Mechanical ventilation is a well-known precipitant of acute lung injury and is strongly associated with the development of acute delirium and anxiety phenotypes. In prior studies, we demonstrated that IL-6 mediates neuropathological changes in the frontal cortex and hippocampus of animals with mechanical ventilation-induced brain injury; however, the effect of systemic IL-6 inhibition on structural and functional acute neuropsychiatric phenotypes is not known. We hypothesized that a murine model of mechanical ventilation-induced acute lung injury (VILI) would induce neural injury to the amygdala and hippocampus, brain regions that are implicated in diverse neuropsychiatric conditions, and corresponding delirium- and anxiety-like functional impairments. Furthermore, we hypothesized that these structural and functional changes would reverse with systemic IL-6 inhibition. VILI was induced using high tidal volume (35 cc/kg) mechanical ventilation. Cleaved caspase-3 (CC3) expression was quantified as a neural injury marker and found to be significantly increased in the VILI group compared to spontaneously breathing or anesthetized and mechanically ventilated mice with 10 cc/kg tidal volume. VILI mice treated with systemic IL-6 inhibition had significantly reduced amygdalar and hippocampal CC3 expression compared to saline-treated animals and demonstrated amelioration in acute neuropsychiatric behaviors in open field, elevated plus maze, and Y-maze tests. Overall, these data provide evidence of a pathogenic role of systemic IL-6 in mediating structural and functional acute neuropsychiatric symptoms in VILI and provide preclinical justification to assess IL-6 inhibition as a potential intervention to ameliorate acute neuropsychiatric phenotypes following VILI.

Inhibition of miR-29b-1-5p Attenuates Inflammatory Response and Pulmonary Fibrosis in LPS-Induced Acute Lung Injury by Regulating RTN4 Expression

Objective

Acute lung injury (ALI) is a severe respiratory disorder causing alveolar-capillary barrier, leading to a high rate of morbidity and death in critically ill individuals. microRNAs (miRNAs)-mediated mechanism in the pathogenesis of ALI has attracted much interest. Herein, we attempt to characterize a candidate miRNA and its downstream target that is linked to the pathogenesis of ALI.

Methods

LPS-conditioned MH-S cells were treated with miR-29a-1-5p mimic, inhibitor, and RNT4 expression vector, and the ALI animal model was injected with agomir and antagomir of miR-29b-1-5p and RNT4 expression vector, in which the pro-inflammatory cytokine production, cell viability and apoptosis, myeloperoxidase (MPO) activity, wet/dry (W/D) ratio, and expression of TGF-β1, α-smooth muscle actin (α-SMA), E-cadherin, and vimentin were examined. miR-29a-1-5p inhibition of RTN4 translation was confirmed by luciferase activity assays.

Results

An elevated miR-29a-1-5p expression was demonstrated in LPS-conditioned MH-S cells. miR-29a-1-5p inhibitor transfection attenuated the production of pro-inflammatory cytokines and MH-S cell viability but enhanced the apoptosis. miR-29a-1-5p inhibition of RTN4 translation was demonstrated in the setting of LPS-induced ALI. LPS-induced murine models demonstrated upregulated miR-29a-1-5p. Intravenous injection of miR-29b-1-5p agomir attenuated mouse lung injury and pulmonary fibrosis. RTN4 overexpression resisting to miR-29a-1-5p overexpression was demonstrated in LPS-induced murine models.

Conclusion

The findings obtained from the study that disturbing the action of miR-29a-1-5p may be a novel therapeutic strategy for preventing ALI.

Intratracheal Administration of Acyl Coenzyme A Acyltransferase-1 Inhibitor K-604 Reduces Pulmonary Inflammation Following Bleomycin-Induced Lung Injury

Acute lung injury (ALI) is characterized by epithelial damage, barrier dysfunction, and pulmonary edema. Macrophage activation and failure to resolve play a role in ALI; thus, macrophage phenotype modulation is a rational target for therapeutic intervention. Large, lipid-laden macrophages have been observed in various injury models, including intratracheal bleomycin (ITB), suggesting that lipid storage may play a role in ALI severity. The endoplasmic reticulum-associated enzyme acyl coenzyme A acyltransferase-1 (Acat-1/Soat1) is highly expressed in macrophages, where it catalyzes the esterification of cholesterol, leading to intracellular lipid accumulation. We hypothesize that inhibition of Acat-1 will reduce macrophage activation and improve outcomes of lung injury in ITB. K-604, a selective inhibitor of Acat-1, was used to reduce cholesterol esterification and hence lipid accumulation in response to ITB. Male and female C57BL6/J mice (n = 16-21/group) were administered control, control + K-604, ITB, or ITB + K-604 on d0, control or K-604 on d3, and were sacrificed on day 7. ITB caused significant body weight loss and an increase in cholesterol accumulation in bronchoalveolar lavage cells. These changes were mitigated by Acat-1 inhibition. K-604 also significantly reduced ITB-induced alveolar thickening. Surfactant composition was normalized as indicated by a significant decrease in phospholipid: SP-B ratio in ITB+K-604 compared with ITB. K-604 administration preserved mature alveolar macrophages, decreased activation in response to ITB, and decreased the percentage mature and pro-fibrotic interstitial macrophages. These results show that inhibition of Acat-1 in the lung is associated with reduced inflammatory response to ITB-mediated lung injury. SIGNIFICANCE STATEMENT: Acyl coenzyme A acyltransferase-1 (Acat-1) is critical to lipid droplet formation, and thus inhibition of Acat-1 presents as a pharmacological target. Intratracheal administration of K-604, an Acat-1 inhibitor, reduces intracellular cholesterol ester accumulation in lung macrophages, attenuates inflammation and macrophage activation, and normalizes mediators of surface-active function after intratracheal bleomycin administration in a rodent model. The data presented within suggest that inhibition of Acat-1 in the lung improves acute lung injury outcomes.

Eupalinolide B attenuates lipopolysaccharide-induced acute lung injury through inhibition of NF-κB and MAPKs signaling by targeting TAK1 protein

Acute lung injury (ALI) is a life-threatening disease characterized by severe inflammatory response, which has no pharmacological therapy in clinic. In this study, we found that eupalinolide B (EB), a sesquiterpene lactone isolated from Eupatorium lindleyanum, significantly ameliorated lipopolysaccharide (LPS)-induced ALI in mice, which manifests as reduction in lung injury score, activity of myeloperoxidase, and release of cytokines interleukin (IL)-1β, IL-6, tumor necrosis factor-α (TNF-α), and monocyte chemoattractant protein-1 (MCP-1). In RAW264.7 murine macrophages, EB effectively inhibited LPS-induced production of nitric oxide (NO) and prostaglandin E2 (PGE₂) by down-regulating the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2), respectively. Mechanistically, EB not only blocked LPS-induced phosphorylation of inhibitor of nuclear factor kappa B kinase-α/β (IKKα/β), phosphorylation and degradation of inhibitor of nuclear factor-kappa B alpha (IκBα), and phosphorylation and nuclear translocation of nuclear factor-kappa B (NF-κB) P65, but also suppressed LPS-induced phosphorylation of mitogen-activated protein kinases (MAPKs) in vitro or in vivo. Through cellular thermal shift assay and western blotting, EB was demonstrated to target and inactivate transforming growth factor β activated kinase-1 (TAK1), which is an important upstream kinase for the activation of NF-κB and MAPKs pathways. Additionally, EB-mediated actions were markedly abolished by dithiothreitol in LPS-exposed RAW264.7 cells, suggesting a crucial role of the α,γ-unsaturated lactone for the anti-inflammatory activity of EB. In conclusion, our findings showed that EB could effectively alleviate ALI in mice, and attenuate inflammatory response by inhibiting the activation of TAK1, and TAK1-mediated activation of NF-κB and MAPKs cascades.

Pyroptosis participates in PM2.5-induced air-blood barrier dysfunction

Epidemiological studies have shown that particulate matters with diameter less than 2.5 μm (PM_2.5) play an important role in inducing and promoting respiratory diseases, but its underlying mechanism remains to be explored. The air-blood barrier, also known as the alveolar-capillary barrier, is the key element of the lung, working as the site of oxygen and carbon dioxide exchange between pulmonary vasculatures. In this study, a mouse PM_2.5 exposure model was established, which leads to an induced lung injury and air-blood barrier disruption. Oxidative stress and pyroptosis were observed in this process. After reducing the oxidative stress by N-acetyl-L-cysteine (NAC) treatment, the air-blood barrier function was improved and the effect of PM_2.5 was alleviated. The level of pyroptosis and related pathway were also effectively relieved. These results indicate that acute PM_2.5 exposure can cause lung injury and the alveolar-capillary barrier disruption by inducing reactive oxygen species (ROS) with the participation of pyroptosis pathway.

Reduction of primary graft dysfunction using cytokine adsorption during organ preservation and after lung transplantation

Despite improvements, lung transplantation remains hampered by both a scarcity of donor organs and by mortality following primary graft dysfunction (PGD). Since acute respiratory distress syndrome (ARDS) limits donor lungs utilization, we investigated cytokine adsorption as a means of treating ARDS donor lungs. We induced mild to moderate ARDS using lipopolysaccharide in 16 donor pigs. Lungs were then treated with or without cytokine adsorption during ex vivo lung perfusion (EVLP) and/or post-transplantation using extracorporeal hemoperfusion. The treatment significantly decreased cytokine levels during EVLP and decreased levels of immune cells post-transplantation. Histology demonstrated fewer signs of lung injury across both treatment periods and the incidence of PGD was significantly reduced among treated animals. Overall, cytokine adsorption was able to restore lung function and reduce PGD in lung transplantation. We suggest this treatment will increase the availability of donor lungs and increase the tolerability of donor lungs in the recipient.

Lung transplantation is hindered by the scarcity of organs and by mortality following primary graft dysfunction. Here, the authors show that cytokine absorption can be used in donor lungs during ex vivo lung perfusion and post-transplant, and leads to restored lung function and reduced primary graft dysfunction in animal models.

Characterization of ENM Dynamic Dose-Dependent MOA in Lung with Respect to Immune Cells Infiltration

The molecular effects of exposures to engineered nanomaterials (ENMs) are still largely unknown. In classical inhalation toxicology, cell composition of bronchoalveolar lavage (BAL) is a toxicity indicator at the lung tissue level that can aid in interpreting pulmonary histological changes. Toxicogenomic approaches help characterize the mechanism of action (MOA) of ENMs by investigating the differentially expressed genes (DEG). However, dissecting which molecular mechanisms and events are directly induced by the exposure is not straightforward. It is now generally accepted that direct effects follow a monotonic dose-dependent pattern. Here, we applied an integrated modeling approach to study the MOA of four ENMs by retrieving the DEGs that also show a dynamic dose-dependent profile (dddtMOA). We further combined the information of the dddtMOA with the dose dependency of four immune cell populations derived from BAL counts. The dddtMOA analysis highlighted the specific adaptation pattern to each ENM. Furthermore, it revealed the distinct effect of the ENM physicochemical properties on the induced immune response. Finally, we report three genes dose-dependent in all the exposures and correlated with immune deregulation in the lung. The characterization of dddtMOA for ENM exposures, both for apical endpoints and molecular responses, can further promote toxicogenomic approaches in a regulatory context.

Lung-kidney interactions and their role in chronic kidney disease-associated pulmonary diseases

Chronic illnesses rarely present in a vacuum, devoid of other complications, and chronic kidney disease is hardly an exception. Comorbidities associated with chronic kidney disease lead to faster disease progression, expedited dialysis dependency, and a higher mortality rate. Although chronic kidney disease is most commonly accompanied by cardiovascular diseases and diabetes, there is clear cross talk between the lungs and kidneys pH balance, phosphate metabolism, and immune system regulation. Our present understanding of the exact underlying mechanisms that contribute to chronic kidney disease-related pulmonary disease is poor. This review summarizes the current research on kidney-pulmonary interorgan cross talk in the context of chronic kidney disease, highlighting various acute and chronic pulmonary diseases that lead to further complications in patient care. Treatment options for patients presenting with chronic kidney disease and lung disease are explored by assessing activated molecular pathways and the body's compensatory response mechanisms following homeostatic imbalance. Understanding the link between the lungs and kidneys will potentially improve health outcomes for patients and guide healthcare professionals to better understand how and when to treat each of the pulmonary comorbidities that can present with chronic kidney disease.

Beyond the Alveolar Epithelium: Plasma Soluble Receptor for Advanced Glycation End Products Is Associated With Oxygenation Impairment, Mortality, and Extrapulmonary Organ Failure in Children With Acute Respiratory Distress Syndrome

OBJECTIVES

Soluble receptor for advanced glycation end products is a known plasma marker of alveolar epithelial injury. However, RAGE is also expressed on cell types beyond the lung, and its activation leads to up-regulation of pro-inflammatory mediators. We sought to examine the relationship between plasma soluble receptor for advanced glycation end products and primary pulmonary dysfunction, extrapulmonary organ dysfunction, and mortality in pediatric acute respiratory distress syndrome patients at two early time points following acute respiratory distress syndrome diagnosis and compare these results to plasma surfactant protein-D, a marker of pure alveolar epithelial injury.

DESIGN

Prospective observational study.

SETTING

Five academic PICUs.

PATIENTS

Two hundred fifty-eight pediatric patients 30 days to 18 years old meeting Berlin Criteria for acute respiratory distress syndrome.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Plasma was collected for soluble receptor for advanced glycation end products and surfactant protein-D measurements within 24 hours (day 1) and 48 to 72 hours (day 3) after acute respiratory distress syndrome diagnosis. Similar to surfactant protein-D, plasma soluble receptor for advanced glycation end products was associated with a higher oxygenation index (p < 0.01) and worse lung injury score (p < 0.001) at the time of acute respiratory distress syndrome diagnosis. However, unlike surfactant protein-D, plasma soluble receptor for advanced glycation end products was associated with worse extrapulmonary Pediatric Logistic Organ Dysfunction score during ICU stay (day 3; p < 0.01) and positively correlated with plasma levels of interleukin-6 (p < 0.01), tumor necrosis factor-α (p < 0.01), and angiopoietin-2 (p < 0.01). Among children with indirect lung injury, plasma soluble receptor for advanced glycation end products was associated with mortality independent of age, sex, race, cancer/bone marrow transplant, and Pediatric Risk of Mortality score (day 3; odds ratio, 3.14; 95% CI, 1.46-6.75; p < 0.01).

CONCLUSIONS

Unlike surfactant protein-D, which is primarily localized to the alveolar epithelium plasma soluble receptor for advanced glycation end products is systemically expressed and correlates with markers of inflammation, extrapulmonary multiple organ dysfunction, and death in pediatric acute respiratory distress syndrome with indirect lung injury. This suggests that unlike surfactant protein-D, soluble receptor for advanced glycation end products is a multifaceted marker of alveolar injury and increased inflammation and that receptor for advanced glycation end products activation may contribute to the pathogenesis of multiple organ failure among children with indirect acute respiratory distress syndrome.

The Effect of Sex-Mismatched Red Blood Cell Transfusion on Endothelial Cell Activation in Critically Ill Patients

BACKGROUND

Observational studies suggest that sex-mismatched transfusion is associated with increased mortality. Mechanisms driving mortality are not known but may include endothelial activation. The aim of this study is to investigate the effects of sex-mismatched red blood cell (RBC) transfusions on endothelial cell activation markers in critically ill patients.

STUDY DESIGN AND METHODS

In patients admitted to the intensive care unit who received a single RBC unit, blood samples were drawn before (T0), 1 h after (T1), and 24 h after transfusion (T24) for analysis of soluble syndecan-1, soluble intercellular adhesion molecule-1, soluble thrombomodulin (sTM), von Willebrand factor antigen, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNFα). Changes in the levels of these factors were compared between sex-matched and sex-mismatched groups.

RESULTS

Of 69 included patients, 32 patients were in the sex-matched and 37 patients were in the sex-mismatched group. Compared to baseline, sex-matched transfusion was associated with significant reduction in sTM level (p value = 0.03). Between-group comparison showed that levels of syndecan-1 and sTM were significantly higher in the sex-mismatched group compared to the sex-matched group at T24 (p value = 0.04 and 0.01, respectively). Also, TNFα and IL-6 levels showed a statistically marginal significant increase compared to baseline in the sex-mismatched group at T24 (p value = 0.06 and 0.05, respectively), but not in the sex-matched group.

DISCUSSION

Transfusion of a single sex-mismatched RBC unit was associated with higher syndecan-1 and sTM levels compared to transfusion of sex-matched RBC unit. These findings may suggest that sex-mismatched RBC transfusion is associated with endothelial activation.

Ex vivo treatment of cytomegalovirus in human donor lungs using a novel chemokine-based immunotoxin

BACKGROUND

Transmission of latent human cytomegalovirus (HCMV) via organ transplantation with post-transplant viral reactivation is extremely prevalent and results in substantial adverse impact on outcomes. Therapies targeting the latent reservoir within the allograft to mitigate viral transmission would represent a major advance. Here, we delivered an immunotoxin (F49A-FTP) that targets and kills latent HCMV aiming at reducing the HCMV reservoir from donor lungs using ex-vivo lung perfusion (EVLP).

METHODS

HCMV seropositive human lungs were placed on EVLP alone or EVLP + 1mg/L of F49A-FTP for 6 hours (n = 6, each). CD14+ monocytes isolated from biopsies pre and post EVLP underwent HCMV reactivation assay designed to evaluate viral reactivation capacity. Off-target effects of F49A-FTP were studied evaluating cell death markers of CD34+ and CD14+ cells using flow cytometry. Lung function on EVLP and inflammatory cytokine production were evaluated as safety endpoints.

RESULTS

We demonstrate that lungs treated ex-vivo with F49A-FTP had a significant reduction in HCMV reactivation compared to controls, suggesting successful targeting of latent virus (76% median reduction in F49A-FTP vs 15% increase in controls, p = 0.0087). Furthermore, there was comparable cell death rates of the targeted cells between both groups, suggesting no off-target effects. Ex-vivo lung function was stable over 6 hours and no differences in key inflammatory cytokines were observed demonstrating safety of this novel treatment.

CONCLUSIONS

Ex-vivo F49A-FTP treatment of human lungs targets and kills latent HCMV, markedly attenuating HCMV reactivation. This approach demonstrates the first experiments targeting latent HCMV in a donor organ with promising results towards clinical translation.

Hederasaponin C Alleviates Lipopolysaccharide-Induced Acute Lung Injury In Vivo and In Vitro Through the PIP2/NF-κB/NLRP3 Signaling Pathway

Gene transcription is governed by epigenetic regulation that is essential for the pro-inflammatory mediators surge following pathological triggers. Acute lung injury (ALI) is driven by pro-inflammatory cytokines produced by the innate immune system, which involves the nod-like receptor 3 (NLRP3) inflammasome and nuclear factor-κB (NF-κB) pathways. These two pathways are interconnected and share a common inducer the phosphatidylinositol 4,5-bisphosphate (PIP2), an epigenetic regulator of (Ribosomal ribonucleic acid (rRNA) gene transcription, to regulate inflammation by the direct inhibition of NF-κB phosphorylation and NLRP3 inflammasome activation. Herein, we report that hederasaponin C (HSC) exerted a therapeutic effect against ALI through the regulation of the PIP2/NF-κB/NLRP3 signaling pathway. In lipopolysaccharide (LPS)/lipopolysaccharide + adenosine triphosphate (LPS+ATP)-stimulated macrophages, our results showed that HSC remarkably inhibited the secretion of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α). Moreover, HSC inhibited NF-κB/p65 nuclear translocation and the binding of PIP2 to transforming growth factor-β activated kinase 1 (TAK1). The intracellular calcium (Ca²⁺) level was decreased by HSC via the PIP2 signaling pathway, which subsequently inhibited the activation of NLRP3 inflammasome. HSC markedly alleviated LPS-induced ALI, restored lung function of mice, and rescued ALI-induced mice death. In addition, HSC significantly reduced the level of white blood cells (WBC), neutrophils, and lymphocytes, as well as pro-inflammatory mediators like IL-6, IL-1β, and TNF-α. Hematoxylin and eosin (H&E) staining results suggested HSC has a significant therapeutic effect on lung injury of mice. Interestingly, the PIP2/NF-κB/NLRP3 signaling pathway was further confirmed by the treatment of HSC with ALI, which is consistent with the treatment of HSC with LPS/LPS+ATP-stimulated macrophages. Overall, our findings revealed that HSC demonstrated significant anti-inflammatory activity through modulating the PIP2/NF-κB/NLRP3 axis in vitro and in vivo, suggesting that HSC is a potential therapeutic agent for the clinical treatment of ALI.

Novel biomarkers for acute respiratory distress syndrome: genetics, epigenetics and transcriptomics

Acute respiratory distress syndrome (ARDS) can be induced by multiple clinical factors, including sepsis, acute pancreatitis, trauma, intestinal ischemia/reperfusion and burns. However, these factors alone may poorly explain the risk and outcomes of ARDS. Emerging evidence suggests that genomic-based or transcriptomic-based biomarkers may hold the promise to establish predictive or prognostic stratification methods for ARDS, and also to help in developing novel therapeutic targets for ARDS. Notably, genetic/epigenetic variations correlated with susceptibility and prognosis of ARDS and circulating microRNAs have emerged as potential biomarkers for diagnosis or prognosis of ARDS. Although limited by sample size, ethnicity and phenotypic heterogeneity, ongoing genetic/transcriptomic research contributes to the characterization of novel biomarkers and ultimately helps to develop innovative therapeutics for ARDS patients.

Design, synthesis and structure-activity relationship studies of 4-indole-2-arylaminopyrimidine derivatives as anti-inflammatory agents for acute lung injury

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS), a clinically high mortality disease, has not been effectively treated till now, and the development of anti-acute lung injury drugs is imminent. Acute lung injury was efficiently treated by inhibiting the cascade of inflammation, and reducing the inflammatory response in the lung. A series of novel compounds with highly efficient inhibiting the expression of inflammatory factors were designed by using 4-indolyl-2-aminopyrimidine as the core skeleton. Totally eleven 4-indolyl-2-arylaminopyrimidine derivatives were designed and synthesized. As well, the related anti-ALI activity of these compounds was evaluated. Compounds 6c and 6h showed a superior activity among these compounds, and the inhibition rate of IL-6 and IL-8 release ranged from 62% to 77%, and from 65% to 72%, respectively. Furthermore, most of compounds had no significant cytotoxicity in vitro. The infiltration of inflammatory cells into lung tissue significantly reduced by using compound 6h (20 mg/kg) in the ALI mice model, which achieved the effect of protecting lung tissue and improving ALI. In addition, the inflammatory response was inhibited by using compound 6h through inhibiting phosphorylation of p-38 and ERK in MAPK signaling pathway, and resulted in protective effect on ALI. These data indicated that compound 6h showed good anti-inflammatory activity in vitro and in vivo, which was expected to become a leading compound for the treatment of ALI.

Corylin Ameliorates LPS-Induced Acute Lung Injury via Suppressing the MAPKs and IL-6/STAT3 Signaling Pathways

Acute lung injury (ALI) is a high mortality disease with acute inflammation. Corylin is a compound isolated from the whole plant of Psoralea corylifolia L. and has been reported to have anti-inflammatory activities. Herein, we investigated the therapeutic potential of corylin on lipopolysaccharides (LPS)-induced ALI, both in vitro and in vivo. The levels of proinflammatory cytokine secretions were analyzed by ELISA; the expressions of inflammation-associated proteins were detected using Western blot; and the number of immune cell infiltrations in the bronchial alveolar lavage fluid (BALF) were detected by multicolor flow cytometry and lung tissues by hematoxylin and eosin (HE) staining, respectively. Experimental results indicated that corylin attenuated LPS-induced IL-6 production in human bronchial epithelial cells (HBEC3-KT cells). In intratracheal LPS-induced ALI mice, corylin attenuated tissue damage, suppressed inflammatory cell infiltration, and decreased IL-6 and TNF-α secretions in the BALF and serum. Moreover, it further inhibited the phosphorylation of mitogen-activated protein kinases (MAPKs), including p-JNK, p-ERK, p-p38, and repressed the activation of signal transducer and activator of transcription 3 (STAT3) in lungs. Collectively, our results are the first to demonstrate the anti-inflammatory effects of corylin on LPS-induced ALI and suggest corylin has significant potential as a novel therapeutic agent for ALI.

V.I.T.A.M. in COVID 19: A Systematic Approach to a Global Pandemic

Introduction

In the unprecedented era of COVID-19, ongoing research and evolution of evidence has led to ever-changing guidelines for clinical monitoring and therapeutic options. Formulating treatment protocols requires the understanding and application of the evolving research.

Objective

The primary objective of this study is to present a systematic evidence-based approach to synthesize the necessary data in order to optimize the management of COVID-19.

Methods

At Mayo Clinic Florida, we developed a multidisciplinary centralized COVID Treatment Review Panel (TRP) of expert pulmonologists, intensivists, infectious disease specialists, anesthesiologists, hematologists, rheumatologists, and hospitalists that in real-time reviews the latest evidence in peer-reviewed journals, the available clinical trials, and help guide the rapid application of therapeutics or interventions to the patient and the bedside provider.

Results/Conclusions

The multi-disciplinary team approach of synthesizing clinical data and coordinating care is effective in responding to rapidly evolving and changing evidence. Systematic data collection and evidence-based treatment algorithms enable physicians to rapidly translate the current literature to clinical practice, and improve care and outcomes of patients.

Potential therapeutic interventions of plant-derived isoflavones against acute lung injury

Acute lung injury (ALI) is a life-threatening syndrome that possibly leads to high morbidity and mortality as no therapy exists. Several natural ingredients with negligible adverse effects have recently been investigated to possibly inhibit the inflammatory pathways associated with ALI at the molecular level. Isoflavones, as phytoestrogenic compounds, are naturally occurring bioactive compounds that represent the most abundant category of plant polyphenols (Leguminosae family). A broad range of therapeutic activities of isoflavones, including antioxidants, chemopreventive, anti-inflammatory, antiallergic and antibacterial potentials, have been extensively documented in the literature. Our review exclusively focuses on the possible anti-inflammatory, antioxidant role of botanicals'-derived isoflavones against ALI and their immunomodulatory effect in experimentally induced ALI. Despite the limited scope covering their molecular mechanisms, isoflavones substantially contributed to protecting from ALI via inhibiting toll-like receptor 4 (TLR4)/Myd88/NF-κB pathway and subsequent cytokines, chemokines, and adherent proteins. Nonetheless, future research is suggested to fill the gap in elucidating the protective roles of isoflavones to alleviate ALI concerning antioxidant potentials, inhibition of the inflammatory pathways, and associated molecular mechanisms.

Intratracheal transplantation of trophoblast stem cells attenuates acute lung injury in mice

Background

Acute lung injury (ALI) is a common lung disorder that affects millions of people every year. The infiltration of inflammatory cells into the lungs and death of the alveolar epithelial cells are key factors to trigger a pathological cascade. Trophoblast stem cells (TSCs) are immune privileged, and demonstrate the capability of self-renewal and multipotency with differentiation into three germ layers. We hypothesized that intratracheal transplantation of TSCs may alleviate ALI.

Methods

ALI was induced by intratracheal delivery of bleomycin (BLM) in mice. After exposure to BLM, pre-labeled TSCs or fibroblasts (FBs) were intratracheally administered into the lungs. Analyses of the lungs were performed for inflammatory infiltrates, cell apoptosis, and engraftment of TSCs. Pro-inflammatory cytokines/chemokines of lung tissue and in bronchoalveolar lavage fluid (BALF) were also assessed.

Results

The lungs displayed a reduction in cellularity, with decreased CD45⁺ cells, and less thickening of the alveolar walls in ALI mice that received TSCs compared with ALI mice receiving PBS or FBs. TSCs decreased infiltration of neutrophils and macrophages, and the expression of interleukin (IL) 6, monocyte chemoattractant protein-1 (MCP-1) and keratinocyte-derived chemokine (KC) in the injured lungs. The levels of inflammatory cytokines in BALF, particularly IL-6, were decreased in ALI mice receiving TSCs, compared to ALI mice that received PBS or FBs. TSCs also significantly reduced BLM-induced apoptosis of alveolar epithelial cells in vitro and in vivo. Transplanted TSCs integrated into the alveolar walls and expressed aquaporin 5 and prosurfactant protein C, markers for alveolar epithelial type I and II cells, respectively.

Conclusion

Intratracheal transplantation of TSCs into the lungs of mice after acute exposure to BLM reduced pulmonary inflammation and cell death. Furthermore, TSCs engrafted into the alveolar walls to form alveolar epithelial type I and II cells. These data support the use of TSCs for the treatment of ALI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02550-z.

miR-128-3p reduced acute lung injury induced by sepsis via targeting PEL12

Objective

Acute lung injury (ALI) caused by sepsis is clinically a syndrome, which is featured by damage to the alveolar epithelium and endothelium. In this study, we employed mice models of cecal ligation and puncture (CLP) and primary mice pulmonary microvascular endothelial cells (MPVECs) in vitro to investigate the effect of miR-128-3p in ALI caused by sepsis.

Methods

miR-128-3p agomir or randomized control were injected into adult male C57BL/6 mice 1 week before the CLP surgery. We used miR-128-3p agomir or scrambled control to transfect MPVECs and then employed lipopolysaccharide (LPS) stimulation on the cells. Pellino homolog 2 (PELI2) was predicted to be a direct target of miR-128-3p via luciferase reporter assay. MPVECs were cotransfected with lentiviral vector that expressed PELI2 (or empty vector) as well as miR-128-3p-mimics 1 day before LPS stimulation in rescue experiment. Transcriptional activity of caspase-3, cell apoptosis rate, and the expression levels of miR-128-3p, interleukin-1β (IL-1β), interleukin-6 (IL-6), and PELI2 were analyzed.

Results

Compared with the sham group, the lung of mice in the CLP group showed pulmonary morphological abnormalities, and the expression of IL-6 and IL-1β, caspase-3 activity, and apoptosis rate were significantly upregulated in the CLP group. Inflammatory factor levels and apoptosis rate were also significantly induced by LPS stimulation on MPVECs. Upregulation of miR-128-3p effectively inhibited sepsis-induced ALI, apoptosis as well as inflammation. miR-128-3p also played a role in antiapoptosis and anti-inflammation in MPVECs with LPS treatment. PEL12 upregulation in MPVECs alleviated miR-128-3p-induced caspase-3 activity inhibition and pro-inflammatory factor production.

Conclusions

miR-128-3p enabled to alleviate sepsis-induced ALI by inhibiting PEL12 expression, indicating a novel treatment strategy of miR-128-3p for sepsis-induced ALI.

Inhibition of microsomal prostaglandin E synthase-1 ameliorates acute lung injury in mice

Background

To examine the effects of BI 1029539 (GS-248), a novel selective human microsomal prostaglandin E synthase-1 (mPGES-1) inhibitor, in experimental models of acute lung injury (ALI) and sepsis in transgenic mice constitutively expressing the mPGES1 (Ptges) humanized allele.

Methods

Series 1: Lipopolysaccharide (LPS)-induced ALI. Mice were randomized to receive vehicle, BI 1029539, or celecoxib. Series 2: Cecal ligation and puncture-induced sepsis. Mice were randomized to receive vehicle or BI 1029539.

Results

Series 1: BI 1029539 or celecoxib reduced LPS-induced lung injury, with reduction in neutrophil influx, protein content, TNF-ɑ, IL-1β and PGE₂ levels in bronchoalveolar lavage (BAL), myeloperoxidase activity, expression of mPGES-1, cyclooxygenase (COX)-2 and intracellular adhesion molecule in lung tissue compared with vehicle-treated mice. Notably, prostacyclin (PGI₂) BAL concentration was only lowered in celecoxib-treated mice. Series 2: BI 1029539 significantly reduced sepsis-induced BAL inflammatory cell recruitment, lung injury score and lung expression of mPGES-1 and inducible nitric oxide synthase. Treatment with BI 1029539 also significantly prolonged survival of mice with severe sepsis. Anti-inflammatory and anti-migratory effect of BI 1029539 was confirmed in peripheral blood leukocytes from healthy volunteers.

Conclusions

BI 1029539 ameliorates leukocyte infiltration and lung injury resulting from both endotoxin-induced and sepsis-induced lung injury.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03016-9.

The impact of fluid status and decremental PEEP strategy on cardiac function and lung and kidney damage in mild-moderate experimental acute respiratory distress syndrome

BACKGROUND

We evaluated the effects of abrupt versus gradual PEEP decrease, combined with standard versus high-volume fluid administration, on cardiac function, as well as lung and kidney damage in an established model of mild-moderate acute respiratory distress syndrome (ARDS).

METHODS

Wistar rats received endotoxin intratracheally. After 24 h, they were treated with Ringer's lactate at standard (10 mL/kg/h) or high (30 mL/kg/h) dose. For 30 min, all animals were mechanically ventilated with tidal volume = 6 mL/kg and PEEP = 9 cmH2O (to keep alveoli open), then randomized to undergo abrupt or gradual (0.2 cmH2O/min for 30 min) PEEP decrease from 9 to 3 cmH2O. Animals were then further ventilated for 10 min at PEEP = 3 cmH2O, euthanized, and their lungs and kidneys removed for molecular biology analysis.

RESULTS

At the end of the experiment, left and right ventricular end-diastolic areas were greater in animals treated with high compared to standard fluid administration, regardless of PEEP decrease rate. However, pulmonary arterial pressure, indicated by the pulmonary acceleration time (PAT)/pulmonary ejection time (PET) ratio, was higher in abrupt compared to gradual PEEP decrease, independent of fluid status. Animals treated with high fluids and abrupt PEEP decrease exhibited greater diffuse alveolar damage and higher expression of interleukin-6 (a pro-inflammatory marker) and vascular endothelial growth factor (a marker of endothelial cell damage) compared to the other groups. The combination of standard fluid administration and gradual PEEP decrease increased zonula occludens-1 expression, suggesting epithelial cell preservation. Expression of club cell-16 protein, an alveolar epithelial cell damage marker, was higher in abrupt compared to gradual PEEP decrease groups, regardless of fluid status. Acute kidney injury score and gene expression of kidney injury molecule-1 were higher in the high versus standard fluid administration groups, regardless of PEEP decrease rate.

CONCLUSION

In the ARDS model used herein, decreasing PEEP abruptly increased pulmonary arterial hypertension, independent of fluid status. The combination of abrupt PEEP decrease and high fluid administration led to greater lung and kidney damage. This information adds to the growing body of evidence that supports gradual transitioning of ventilatory patterns and warrants directing additional investigative effort into vascular and deflation issues that impact lung protection.

Critical Role of Mortalin/GRP75 in Endothelial Cell Dysfunction Associated with Acute Lung Injury

Mortalin/GRP75 (glucose regulated protein 75), a member of heat shock protein 70 family of chaperones, is involved in several cellular processes including proliferation and signaling, and plays a pivotal role in cancer and neurodegenerative disorders. In this study, we sought to determine the role of mortalin/GRP75 in mediating vascular inflammation and permeability linked to the pathogenesis of acute lung injury (ALI). In an aerosolized bacterial lipopolysaccharide inhalation mouse model of ALI, we found that administration of mortalin/GRP75 inhibitor mean kinetic temperature-077, both prophylactically and therapeutically, protected against polymorphonuclear leukocytes influx into alveolar airspaces, microvascular leakage, and expression of pro-inflammatory mediators such as interleukin-1β, E-selectin, and tumor necrosis factor TNFα. Consistent with this, thrombin-induced inflammation in cultured human endothelial cells (EC) was also protected upon before and after treatment with mean kinetic temperature-077. Similar to pharmacological inhibition of mortalin/GRP75, siRNA-mediated depletion of mortalin/GRP75 also blocked thrombin-induced expression of proinflammatory mediators such as intercellular adhesion molecule-1 and vascular adhesion molecule-1. Mechanistic analysis in EC revealed that inactivation of mortalin/GRP75 interfered with the binding of the liberated NF-κB to the DNA, thereby leading to inhibition of downstream expression of adhesion molecules, cytokines, and chemokines. Importantly, thrombin-induced Ca signaling and EC permeability were also prevented upon mortalin/GRP75 inactivation/depletion. Thus, this study provides evidence for a novel role of mortalin/GRP75 in mediating EC inflammation and permeability associated with ALI.

Long-term survivors of murine sepsis are predisposed to enhanced LPS-induced lung injury and proinflammatory immune reprogramming

Millions of people who survive sepsis each year are rehospitalized and die due to late pulmonary complications. To prevent and treat these complications, biomarkers and molecular mediators must be identified. Persistent immune reprogramming in the form of immunoparalysis and impaired host defense is proposed to mediate late pulmonary complications after sepsis, particularly new pulmonary infections. However, immune reprogramming may also involve enhanced/primed responses to secondary stimuli, although their contribution to long-term sepsis complications remains understudied. We hypothesize that enhanced/primed immune responses in the lungs of sepsis survivors are associated with late pulmonary complications. To this end, we developed a murine sepsis model using cecal ligation and puncture (CLP) followed 3 wk later by administration of intranasal lipopolysaccharide to induce inflammatory lung injury. Mice surviving sepsis exhibit enhanced lung injury with increased alveolar permeability, neutrophil recruitment, and enhanced Ly6C^hi monocyte Tnf expression. To determine the mediators of enhanced lung injury, we performed flow cytometry and RNA sequencing of lungs 3 wk after CLP, prior to lipopolysaccharide. Sepsis survivor mice showed expanded Ly6C^hi monocytes populations and increased expression of many inflammatory genes. Of these, S100A8/A9 was also elevated in the circulation of human sepsis survivors for months after sepsis, validating our model and identifying S100A8/A9 as a potential biomarker and therapeutic target for long-term pulmonary complications after sepsis. These data provide new insight into the importance of enhanced/primed immune responses in survivors of sepsis and establish a foundation for additional investigation into the mechanisms mediating this response.

CircANKRD36 Knockdown Suppressed Cell Viability and Migration of LPS-Stimulated RAW264.7 Cells by Sponging MiR-330

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is an independent risk factor for mortality in patients with sepsis. In this study, we attempt to investigate the molecular mechanism of circANKRD36 underlying sepsis-induced ALI/ARDS in vitro. We first detected the altered circRNAs in serums of patients with sepsis-induced ARDS using circRNAs microarray. CircANKRD36 expression in serums and LPS-stimulated RAW264.7 cells was measured using qRT-PCR. CCK-8, cell migration, ELISA, and qRT-PCR were applied to the evaluation of cell biological behavior and inflammation reaction. The results showed that circANKRD36 expression was significantly elevated in serum of patients with sepsis-induced ARDS. Knockdown of circANKRD36 inhibited cell viability and migration and alleviated inflammation of lipopolysaccharide-stimulated (LPS-stimulated) RAW264.7 cells. Bioinformatic analysis demonstrated that circANKRD36 serves as a sponge for miR-330 and ROCK1 was directly targeted by miR-330. Furthermore, knockdown of circANKRD36 repressed ROCK1 expression by targeting miR-330. In short, circANKRD36 knockdown suppressed cell viability and migration of LPS-stimulated RAW264.7 cells in vitro via sponging miR-330, which may provide new ideas for the treatment of sepsis-induced ARDS.