Transient receptor potential vanilloid 4 is a critical mediator in LPS mediated inflammation by mediating calcineurin/NFATc3 signaling.

Transient Receptor Potential Vanilloid 4 (TRPV4) ion channel is thought to be an essential component of inflammatory response. However, its role and mechanism in regulating acute lung injury (ALI) and macrophages activation are not well characterized. In our study, we observe that blockade of TRPV4 using GSK2193874 or HC-067047 greatly improve the pneumonedema, the lung pathologic changes, the up-regulation of proinflammatory cytokines and the neutrophil infiltration in LPS-induced lung injury. In vitro, knockdown of TRPV4 in macrophages reduces the levels of pro-inflammatory cytokines, ROS production, Ca2+ concentration in cytoplasma and the activation of calcineurin/NFATc3 signaling. Importantly, change of extracellular Ca2+ in culture medium prevents LPS-induced NFATc3 nuclear translocation, up-regulation of proinflammatory cytokines and ROS production in macrophages. Inhibition of calcineurin with cyclosporine A, FK506 down-regulates the levels of NFATc3 nuclear translocation and proinflammatory cytokines expression. Our results demonstrate that TRPV4-dependent Ca2+ influx contributes to LPS-induced macrophage activation by calcineurin-NFATc3 pathway.

Safety and Efficacy of Dexmedetomidine as a Sedative Agent for Performing Awake Intubation: A Meta-analysis.

To compare the efficacy and safety of dexmedetomidine with other alternative sedative agents used for performing awake intubation. We conducted a meta-analysis of randomized controlled trials (RCTs) that compared the effects of dexmedetomidine with other alternative sedative agents used during awake intubation. The biomedical databases PubMed, Science Direct, and the Cochrane Library were searched for relevant RCTs with no restriction on the language of publication. The efficacy (level of sedation, success rate for intubation at the first attempt, intubation time, intubation conditions, and patient satisfaction) and safety (incidence of hypertension, hypotension, tachycardia, bradycardia, hypoxia, postsurgical memory, hoarseness, and sore throat) were assessed. Thirteen RCTs with a combined subject population of 591 patients came within the purview of this meta-analysis. Use of dexmedetomidine was associated with a higher Ramsay sedation scale score [mean difference (MD): 1.02, 95% confidence interval (CI), 0.77-1.28, P < 0.00001], vocal cord movement score (MD = 0.72, 95% CI, 0.20-1.24, P = 0.007), coughing scores (MD = 0.66, 95% CI, 0.10-1.22, P = 0.02), limb movement scores (MD = 0.69, 95% CI, 0.47-0.91, P < 0.00001); increased risk of bradycardia [relative risk (RR): 3.03, 95% CI, 1.38-6.68, P = 0.006] and hypotension (RR: 2.87, 95% CI, 1.44-5.75, P = 0.003); and lower risk of hypoxia (RR: 0.32, 95% CI, 0.15-0.70; P = 0.004) and postsurgical memory (RR: 0.50, 95% CI, 0.35-0.72, P = 0.0002). As indicated by our results, dexmedetomidine appears to be an effective and well-tolerated agent for performing awake intubation. Its use was associated with better intubation conditions, preservation of airway patency, and reduced recall of intubation, as compared with the traditional sedative agents. The risk of bradycardia and hypotension was significantly higher with dexmedetomidine as compared with that with other sedatives. However, these were easily managed with atropine and vasoactive agents.

Network Meta-Analysis on the Efficacy of Dexmedetomidine, Midazolam, Ketamine, Propofol, and Fentanyl for the Prevention of Sevoflurane-Related Emergence Agitation in Children.

Sevoflurane is associated with a relatively high incidence of emergence agitation (EA) in children. Prophylactic treatment, including midazolam, dexmedetomidine, ketamine, fentanyl and propofol, has been used to prevent EA. However, the question of which prophylactic treatment should be preferred to decrease the incidence of EA is still unclear. We conducted a network meta-analysis of randomized controlled trials to investigate the comparative efficacy of midazolam, dexmedetomidine, ketamine, fentanyl, and propofol for the prevention of sevoflurane-related EA in children. First, we used the odds ratios and 95% confidence interval as effect size. The results revealed that dexmedetomidine 0.19 (0.14-0.27), midazolam 0.22 (0.07-0.60), ketamine 0.28 (0.16-0.51), propofol 0.23 (0.10-0.53), and fentanyl 0.25 (0.17-0.36) led to a significant reduction of the incidence of EA when compared with placebo. With placebo as the standard of comparison, the degree of incoherence (a measure of how closely the entire network fits together) was small (ω = 8.66728e-08). The logor were dexmedetomidine -1.75 (-2.11 to -1.39), midazolam -1.07 (-1.54 to -0.60), ketamine -1.292 (-1.92 to -0.66), and fentanyl -1.13 (-1.56 to -0.70). When compared with dexmedetomidine, the logor were placebo 1.75 (1.39-2.11), midazolam 0.67 (0.09-1.25), ketamine 0.45 (-0.25-1.15), propofol 0.75 (0.19-1.31), and fentanyl 0.617 (0.13-1.11). When compared with ketamine, the logor were placebo 1.29 (0.66-1.92), midazolam 0.22 (-0.56 to 1.00), dexmedetomidine -0.45 (-1.15-0.25); propofol 0.29 (-0.45-1.03); and fentanyl 0.16 (-0.59-0.92). The study that showed dexmedetomidine, midazolam, ketamine, propofol, and fentanyl could significantly decrease the incidence of EA when compared with placebo. One interesting finding of this network meta-analysis is that dexmedetomidine might be the best choice to prevent EA. However, there is weak evidence that dexmedetomidine is better than ketamine for the prevention of sevoflurane-related EA in children. As a result, more studies are needed to compare dexmedetomidine with ketamine.

Mechanosensitive ion channel Piezo1 mediates mechanical ventilation-exacerbated ARDS-associated pulmonary fibrosis.

INTRODUCTION: Pulmonary fibrosis is a major cause of the poor prognosis of acute respiratory distress syndrome (ARDS). While mechanical ventilation (MV) is an indispensable life-saving intervention for ARDS, it may cause the remodeling process in lung epithelial cells to become disorganized and exacerbate ARDS-associated pulmonary fibrosis. Piezo1 is a mechanosensitive ion channel that is known to play a role in regulating diverse physiological processes, but whether Piezo1 is necessary for MV-exacerbated ARDS-associated pulmonary fibrosis remains unknown. OBJECTIVES: This study aimed to explore the role of Piezo1 in MV-exacerbated ARDS-associated pulmonary fibrosis. METHODS: Human lung epithelial cells were stimulated with hydrochloric acid (HCl) followed by mechanical stretch for 48 h. A two-hitmodel of MV afteracidaspiration-inducedlunginjuryin mice was used. Mice were sacrificed after 14 days of MV. Pharmacological inhibition and knockout of Piezo1 were used to delineate the role of Piezo1 in MV-exacerbated ARDS-associated pulmonary fibrosis. In some experiments, ATP or the ATP-hydrolyzing enzyme apyrase was administered. RESULTS: The stimulation of human lung epithelial cells to HCl resulted in phenotypes of epithelial-mesenchymal transition (EMT), which were enhanced by mechanical stretching. MV exacerbated pulmonary fibrosis in mice exposed to HCl. Pharmacologicalinhibitionorknockout of Piezo1 attenuated the MV-exacerbated EMT process and lung fibrosis in vivo and in vitro. Mechanistically, the observed effects were mediated by Piezo1-dependent Ca2+ influx and ATP release in lung epithelial cells. CONCLUSIONS: Our findings identify a key role for Piezo1 in MV-exacerbated ARDS-associated pulmonary fibrosis that is mediated by increased ATP release in lung epithelial cells. Inhibiting Piezo1 may constitute a novelstrategyfor the treatment of MV-exacerbated ARDS-associated pulmonary fibrosis.

Immunothrombosis in Acute Respiratory Dysfunction of COVID-19.

COVID-19 is an acute, complex disorder that was caused by a new ß-coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Based on current reports, it was surprising that the characteristics of many patients with COVID-19, who fulfil the Berlin criteria for acute respiratory distress syndrome (ARDS), are not always like those of patients with typical ARDS and can change over time. While the mechanisms of COVID-19-related respiratory dysfunction in COVID-19 have not yet been fully elucidated, pulmonary microvascular thrombosis is speculated to be involved. Considering that thrombosis is highly related to other inflammatory lung diseases, immunothrombosis, a two-way process that links coagulation and inflammation, seems to be involved in the pathophysiology of COVID-19, including respiratory dysfunction. Thus, the current manuscript will describe the proinflammatory milieu in COVID-19, summarize current evidence of thrombosis in COVID-19, and discuss possible interactions between these two.

Structure, kinetic properties and biological function of mechanosensitive Piezo channels.

Mechanotransduction couples mechanical stimulation with ion flux, which is critical for normal biological processes involved in neuronal cell development, pain sensation, and red blood cell volume regulation. Although they are key mechanotransducers, mechanosensitive ion channels in mammals have remained difficult to identify. In 2010, Coste and colleagues revealed a novel family of mechanically activated cation channels in eukaryotes, consisting of Piezo1 and Piezo2 channels. These have been proposed as the long-sought-after mechanosensitive cation channels in mammals. Piezo1 and Piezo2 exhibit a unique propeller-shaped architecture and have been implicated in mechanotransduction in various critical processes, including touch sensation, balance, and cardiovascular regulation. Furthermore, several mutations in Piezo channels have been shown to cause multiple hereditary human disorders, such as autosomal recessive congenital lymphatic dysplasia. Notably, mutations that cause dehydrated hereditary xerocytosis alter the rate of Piezo channel inactivation, indicating the critical role of their kinetics in normal physiology. Given the importance of Piezo channels in understanding the mechanotransduction process, this review focuses on their structural details, kinetic properties and potential function as mechanosensors. We also briefly review the hereditary diseases caused by mutations in Piezo genes, which is key for understanding the function of these proteins.

Glucocorticoid-Induced Leucine Zipper: A Promising Marker for Monitoring and Treating Sepsis.

Sepsis is a clinical syndrome that resulting from a dysregulated inflammatory response to infection that leads to organ dysfunction. The dysregulated inflammatory response transitions from a hyper-inflammatory phase to a hypo-inflammatory or immunosuppressive phase. Currently, no phase-specific molecular-based therapies are available for monitoring the complex immune response and treating sepsis due to individual variations in the timing and overlap of the dysregulated immune response in most patients. Glucocorticoid-induced leucine zipper (GILZ), is broadly present in multiple tissues and circumvent glucocorticoid resistance (GCR) or unwanted side effects. Recently, the characteristics of GILZ downregulation during acute hyperinflammation and GILZ upregulation during the immunosuppressive phase in various inflammatory diseases have been well documented, and the protective effects of GILZ have gained attention in the field of sepsis. However, whether GILZ could be a promising candidate biomarker for monitoring and treating septic patients remains unknown. Here, we discuss the effect of GILZ in sepsis and sepsis-induced immunosuppression.

NecroX-5 alleviate lipopolysaccharide-induced acute respiratory distress syndrome by inhibiting TXNIP/NLRP3 and NF-κB.

The activation of NLRP3 inflammasome and NF-κB pathway, associating with oxidativestress, have been implicated in the development of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). NecroX-5 has been reported to exhibit theeffectsofanti-oxidation and anti-stress in various diseases. However, the role of NecroX-5 in ALI has not been explicitly demonstrated. The aim of this study was to explore the therapeutic effects and potential mechanism action of NecroX-5 on ALI. Here, we found that NecroX-5 pretreatment dramatically diminished the levels of IL-1ß, IL-18 and ROS in in RAW264.7 cells challenged with LPS and ATP. Furthermore, NecroX-5 suppressed the activation of NLRP3 inflammasome and NF-κB signalpathway. In addition, NecroX-5 also inhibited the thioredoxin-interacting protein (TXNIP) expression. In vivo, NecroX-5 reduced the LPS-induced lung histopathological injury, the number of TUNEL-positive cells, lung wet/dry (W/D) ratio, levels of total protein and inflammatory cytokines in the bronchoalveolar lavage fluid (BALF) in mice. Additionally, LPS-induced upregulation of myeloperoxidase (MPO), ROS production and malondialdehyde (MDA) were inhibited by NecroX-5 administration. Thus, our results demonstrate that NecroX-5 protects against LPS-induced ALI by inhibiting TXNIP/NLRP3 and NF-κB.

Inhibition of calcineurin/NFATc4 signaling attenuates ventilator­induced lung injury.

Ventilator­induced lung injury (VILI) is a life­threatening condition caused by the inappropriate use of mechanical ventilation (MV). However, the precise molecular mechanism inducing the development of VILI remains to be elucidated. In the present study, it was revealed that the calcineurin/NFATc4 signaling pathway mediates the expression of adhesion molecules and proinflammatory cytokines essential for the development of VILI. The present results revealed that a high tidal volume ventilation (HV) caused lung inflammation and edema in the alveolar walls and the infiltration of inflammatory cells. The calcineurin activity and protein expression in the lungs were increased in animals with VILI, and NFATc4 translocated into the nucleus following calcineurin activation. Furthermore, the translocation of NFATc4 and lung injury were prevented by a calcineurin inhibitor (CsA). Thus, the present results highlighted the critical role of the calcineurin/NFATc4 signaling pathway in VILI and suggest that this pathway coincides with the release of ICAM­1, VCAM­1, TNF­α and IL­1ß.

Preconditioning of physiological cyclic stretch inhibits the inflammatory response induced by pathologically mechanical stretch in alveolar epithelial cells.

The aim of the present study was to investigate the effects of preconditioning of physiological cyclic stretch (CS) on the overexpression of early pro-inflammatory cytokines [including tumor necrosis factor (TNF)-α, interleukin (IL)-1ß and IL-8] during the inflammatory response induced by pathologically mechanical stretch in lung epithelial cells, and to determine its molecular mechanism of action. Cells were subjected to 5% CS for various durations (0, 15, 30, 60 and 120 min) prior to 6 h treatment with pathological 20% CS. In a separate experiment, cells were preconditioned with physiological 5% CS or incubated with a nuclear factor (NF)-κB inhibitor, pyrroldine dithiocarbamate (PDTC). The expression levels of inflammatory mediators were measured using reverse transcription-quantitative polymerase chain reaction. NF-κB was quantified using western blot analysis. Preconditioning with physiological 5% CS for 30, 60 and 120 min was demonstrated to significantly attenuate the release of pathologically mechanical stretch-induced early pro-inflammatory cytokines (TNF-α, IL-1ß and IL-8) in alveolar epithelial cells (P<0.05) and significantly reduce the expression of NF-κB (P<0.05). Peak suppression was observed in cells preconditioned for 60 min. In the second set of experiments, it was demonstrated that mechanical stretch-induced release of TNF-α, IL-1ß and IL-8 was significantly inhibited by both PDTC pretreatment and 5% CS pretreatment alone (all P<0.05). Furthermore, significant inhibition was also observed when both 5% CS pretreatment and PDTC pretreatment was used on mechanical stretch-induced cells (P<0.05), which was markedly greater than the inhibition induced by either pretreatment alone. The present findings suggest that preconditioning with physiological 5% CS is able to inhibit the inflammatory response induced by pathologically mechanical stretch in alveolar epithelial cells. These anti-inflammatory effects are induced, at least in part, by suppressing the NF-κB signaling pathway.

Comparison of single- and triple-injection methods for ultrasound-guided interscalene brachial plexus blockade.

Ultrasound-guided interscalene brachial plexus blockade (IBPB) has a relatively high success rate in shoulder surgery; however, whether multiple injections are superior to a single injection (SI) is currently unknown. In the present study, ultrasound-guided SI and triple-injection (TI) IBPBs were compared in a prospective randomized trial. A total of 111 patients undergoing arthroscopic shoulder surgery and presenting with an American Society of Anesthesiologists physical status grading of I-II were randomly allocated to receive IBPB with 15 ml of 1% ropivacaine as a SI or TI. Performance time, procedure-related pain scores, success rate and prevalence of complications were recorded. The distribution of sensory and motor block onset in the radial, median, ulnar and axillary nerves were assessed every 5 min until 30 min post-local anesthetic injection. The duration of sensory and motor blocks were also assessed. A significantly longer performance time was recorded in the TI group (P<0.001). No significant difference was observed in success rate (91% in TI vs. 88% in SI) 30 min post-injection, and the prevalence of complications and procedure-related pain were similar between the two groups. Sensory and motor blocks of the ulnar nerve in the TI group were significantly faster and more successful compared with the SI group at all time points (P<0.041). It was also observed that sensory and motor blocks in the TI group were prolonged compared with the SI group (P<0.041). In conclusion, the TI method exhibited a faster time of onset and resulted in a more successful blockade of the ulnar nerve. TI method may be a more effective approach for IBPB in a clinical setting.

miR-127 contributes to ventilator-induced lung injury.

Although it is essential in critical care medicine, mechanical ventilation often results in ventilator­induced lung injury (VILI). Treating mice with lipopolysaccharide has been reported to upregulate the expression of miR­127, which has been implicated in the modulation of immune responses. However, the putative roles of miR­127 during the development of VILI have yet to be elucidated. The present study demonstrated that challenging mice with mechanical ventilation for 6 h significantly upregulated the expression of miR­127 in bronchoalveolar lavage fluid, serum and lung tissue samples. Conversely, following the downregulation of miR­127 expression in vivo using an adenovirus delivery system, VILI­associated pathologies, including alterations in the pulmonary wet/dry ratio, pulmonary permeability, lung neutrophil infiltration and levels of pro­inflammatory cytokines, were significantly attenuated. In addition, miR­127 knockdown inhibited the ventilation­induced activation of nuclear factor (NF)­κB and p38 mitogen­activated protein kinase (MAPK). These findings suggested that the upregulation of miR­127 expression may contribute to the development of VILI, through the modulation of pulmonary permeability, the induction of histopathological alterations, and the potentiation of inflammatory responses involving NF­κB and p38 MAPK­associated signaling pathways.

Preconditioning of physiological cyclic stretch attenuated HMGB1 expression in pathologically mechanical stretch-activated A549 cells and ventilator-induced lung injury rats through inhibition of IL-6/STAT3/SOCS3.

Previous studies have shown that physiologically cyclic stretch (5% CS) attenuated both oxidative- and LPS-induced increases in HMGB1 expression via STAT3. However, little information exists about the effect of precondition of physiological cyclic stretch (CS) on the expression of HMGB 1, which play a crucial role in ventilator-induced lung injury (VILI). We found that 5% CS-preconditioning significantly inhibited HMGB 1 expression, but not HMGB 1 receptors. 5% CS-preconditioning inhibits the IL-6/STAT3 pathway, and the inhibitory effect on the expression of HMGB 1 induced by 5% CS-preconditioning is abolished by additional treatment of rmIL-6. 5% CS-preconditioning also induces SOCS3 upregulation, and 5% CS-preconditioning fails to inhibit the IL-6/STAT3 pathway in cells transfected with SOCS3 siRNA. Moreover, low tidal volume ventilation preconditioning also decreases the severity of VILI evidenced by the markedly improved pulmonary alveolar-capillary barrier dysfunction, wet/dry weight ratio, and histological analysis. These results suggest that preconditioning of physiological 5% CS can reduce the expression of HMGB 1 induced by pathologically mechanical stretch through IL-6/STAT3 pathway associated with up-regulated SOCS3 expression.