Acute Lung Injury/acute Respiratory Distress Syndrome Research Articles

Cepharanthine Dry Powder Inhaler for the Treatment of Acute Lung Injury.

Severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) induces a severe cytokine storm that may cause acute lung injury/acute respiratory distress syndrome (ALI/ARDS) with high clinical morbidity and mortality in infected individuals. Cepharanthine (CEP) is a bisbenzylisoquinoline alkaloid isolated and extracted from Stephania cepharantha Hayata. It exhibits various pharmacological effects, including antioxidant, anti-inflammatory, immunomodulatory, anti-tumor, and antiviral activities. The low oral bioavailability of CEP can be attributed to its poor water solubility. In this study, we utilized the freeze-drying method to prepare dry powder inhalers (DPI) for the treatment of acute lung injury (ALI) in rats via pulmonary administration. According to the powder properties study, the aerodynamic median diameter (Da) of the DPIs was 3.2 μm, and the in vitro lung deposition rate was 30.26; thus, meeting the Chinese Pharmacopoeia standard for pulmonary inhalation administration. We established an ALI rat model by intratracheal injection of hydrochloric acid (1.2 mL/kg, pH = 1.25). At 1 h after the model's establishment, CEP dry powder inhalers (CEP DPIs) (30 mg/kg) were sprayed into the lungs of rats with ALI via the trachea. Compared with the model group, the treatment group exhibited a reduced pulmonary edema and hemorrhage, and significantly reduced content of inflammatory factors (TNF-α, IL-6 and total protein) in their lungs (p < 0.01), indicating that the main mechanism of CEP underlying the treatment of ALI is anti-inflammation. Overall, the dry powder inhaler can deliver the drug directly to the site of the disease, increasing the intrapulmonary utilization of CEP and improving its efficacy, making it a promising inhalable formulation for the treatment of ALI.

Inhaled aptamer therapy: A hopeful therapy for lung disease

Inhaled aptamer therapy: A hopeful therapy for lung disease

Upregulation of alveolar fluid clearance is not sufficient for Na+,K+-ATPase β subunit-mediated gene therapy of LPS-induced acute lung injury in mice

Acute Lung Injury/Acute Respiratory Distress Syndrome (ALI/ARDS) is characterized by diffuse alveolar damage and significant edema accumulation, which is associated with impaired alveolar fluid clearance (AFC) and alveolar‐capillary barrier disruption, leading to acute respiratory failure. Our previous data showed that electroporation‐mediated gene delivery of the Na+, K+-ATPase β1 subunit not only increased AFC, but also restored alveolar barrier function through upregulation of tight junction proteins, leading to treatment of LPS‐induced ALI in mice. More importantly, our recent publication showed that gene delivery of MRCKα, the downstream effector of β1 subunit-mediated signaling towards upregulation of adhesive junctions and epithelial and endothelial barrier integrity, also provided therapeutic potential for ARDS treatment in vivo but without necessarily accelerating AFC, indicating that for ARDS treatment, improving alveolar capillary barrier function may be of more benefit than improving fluid clearance. In the present study, we investigated the therapeutical potential of β2 and β3 subunits, the other two β isoforms of Na+, K+-ATPase, for LPS‐induced ALI. We found that gene transfer of either the β1, β2, or β3 subunits significantly increased AFC compared to the basal level in naïve animals and each gave similar increased AFC to each other. However, unlike that of the β1 subunit, gene transfer of the β2 or β3 subunit into pre-injured animal lungs failed to show the beneficial effects of attenuated histological damage, neutrophil infiltration, overall lung edema, or increased lung permeability, indicating that β2 or β3 gene delivery could not treat LPS induced lung injury. Further, while β1 gene transfer increased levels of key tight junction proteins in the lungs of injured mice, that of either the β2 or β3 subunit had no effect on levels of tight junction proteins. Taken together, this strongly suggests that restoration of alveolar-capillary barrier function alone may be of equal or even more benefit than improving AFC for ALI/ARDS treatment.

THE IL-33/ST2 AXIS PROMOTES ACUTE RESPIRATORY DISTRESS SYNDROME BY NATURAL KILLER T CELLS.

Acute respiratory distress syndrome (ARDS) is characterized by uncontrolled inflammation, which manifests as leukocyte infiltration and lung injury. However, the molecules that initiate this infiltration remain incompletely understood. We evaluated the effect of the nuclear alarmin IL-33 on lung damage and the immune response in LPS-induced lung injury. We established a LPS-induced lung injury mouse model. We used genetically engineered mice to investigate the relationship among the IL-33/ST2 axis, NKT cells, and ARDS. We found that IL-33 was localized to the nucleus in alveolar epithelial cells, from which it was released 1 h after ARDS induction in wild-type (WT) mice. Mice lacking IL-33 (IL-33 - / - ) or ST2 (ST2 - / - ) exhibited reduced neutrophil infiltration, alveolar capillary leakage, and lung injury in ARDS compared with WT mice. This protection was associated with decreased lung recruitment and activation of invariant nature killer (iNKT) cells and activation of traditional T cells. Then, we validated that iNKT cells were deleterious in ARDS in CD1d - / - and Vα14Τg mice. Compared with WT mice, Vα14Τg mice exhibited increased lung injury in ARDS, and the CD1d - / - mice showed outcomes opposite those of the Vα14Τg mice. Furthermore, we administered a neutralizing anti-ST2 antibody to LPS-treated WT and Vα14Τg mice 1 h before LPS administration. We found that IL-33 promoted inflammation through NKT cells in ARDS. In summary, our results demonstrated that the IL-33/ST2 axis promotes the early uncontrolled inflammatory response in ARDS by activating and recruiting iNKT cells. Therefore, IL-33 and NKT cells may be therapeutic target molecules and immune cells, respectively, in early ARDS cytokine storms.

Inhibition of fatty acid synthase protects obese mice from acute lung injury via ameliorating lung endothelial dysfunction

BackgroundObesity has been identified as a risk factor for acute lung injury/acute respiratory distress syndrome (ALI/ARDS). However, the underlying mechanisms remain elusive. This study aimed to investigate the role of fatty acid synthase (FASN) in lipopolysaccharide (LPS)-induced ALI under obesity.MethodsA high-fat diet-induced obese (DIO) mouse model was established and lean mice fed with regular chow diet were served as controls. LPS was intratracheally instilled to reproduce ALI in mice. In vitro, primary mouse lung endothelial cells (MLECs), treated by palmitic acid (PA) or co-cultured with 3T3-L1 adipocytes, were exposed to LPS. Chemical inhibitor C75 or shRNA targeting FASN was used for in vivo and in vitro loss-of-function studies for FASN.ResultsAfter LPS instillation, the protein levels of FASN in freshly isolated lung endothelial cells from DIO mice were significantly higher than those from lean mice. MLECs undergoing metabolic stress exhibited increased levels of FASN, decreased levels of VE-cadherin with increased p38 MAPK phosphorylation and NLRP3 expression, mitochondrial dysfunction, and impaired endothelial barrier compared with the control MLECs when exposed to LPS. However, these effects were attenuated by FASN inhibition with C75 or corresponding shRNA. In vivo, LPS-induced ALI, C75 pretreatment remarkably alleviated LPS-induced overproduction of lung inflammatory cytokines TNF-α, IL-6, and IL-1β, and lung vascular hyperpermeability in DIO mice as evidenced by increased VE-cadherin expression in lung endothelial cells and decreased lung vascular leakage.ConclusionsTaken together, FASN inhibition alleviated the exacerbation of LPS-induced lung injury under obesity via rescuing lung endothelial dysfunction. Therefore, targeting FASN may be a potential therapeutic target for ameliorating LPS-induced ALI in obese individuals.

Targeting Receptor-Interacting Protein Kinase 1 by Novel Benzothiazole Derivatives: Treatment of Acute Lung Injury through the Necroptosis Pathway.

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) are serious and devastating pulmonary manifestations of acute systemic inflammation with high morbidity and mortality worldwide. Currently, there are no specific effective treatments for ALI/ARDS. RIPK1, which contributes to necroptosis and inflammation, is confirmed to be a promising strategy for the treatment of ALI. Herein, 23 benzothiazole derivatives were designed to specifically target RIPK1, and SZM-1209 showed high anti-necroptotic activity (EC50 = 22.4 nM) and kinase selectivity on RIPK1 over RIPK3 (Kd,RIPK1 = 85 nM, Kd,RIPK3 > 10,000 nM). In a mTNF-α-induced systemic inflammatory response syndrome (SIRS) model, SZM-1209 could completely reverse mouse deaths with significant anti-inflammatory effects. Furthermore, in a NNK short-term intratracheal exposure-induced ALI model, SZM-1209 significantly alleviated ALI by reducing pulmonary edema and pathological damage. Collectively, activities of SZM-1209 against RIPK1, necroptosis, SIRS, and ALI warranted further investigation of optimized benzothiazoles as promising lead structures against ALI-related diseases.

Overexpression of FoxM1 optimizes the therapeutic effect of bone marrow mesenchymal stem cells on acute respiratory distress syndrome

BackgroundInjury of alveolar epithelial cells and capillary endothelial cells is crucial in the pathogenesis of acute lung injury/acute respiratory distress syndrome (ALI/ARDS). Mesenchymal stem cells (MSCs) are a promising cell source for ALI/ARDS treatment. Overexpression of Fork head box protein M1 (FoxM1) facilitates MSC differentiation into alveolar type II (AT II) cells in vitro. Moreover, FoxM1 has been shown to repair the endothelial barrier. Therefore, this study explored whether overexpression of FoxM1 promotes the therapeutic effect of bone marrow-derived MSCs (BMSCs) on ARDS by differentiation of BMSCs into AT II cells or a paracrine mechanism.MethodsA septic ALI model was established in mice by intraperitoneal administration of lipopolysaccharide. The protective effect of BMSCs-FoxM1 on ALI was explored by detecting pathological variations in the lung, total protein concentration in bronchoalveolar lavage fluid (BALF), wet/dry (W/D) lung weight ratio, oxidative stress levels, cytokine levels, and retention of BMSCs in the lung. In addition, we assessed whether FoxM1 overexpression promoted the therapeutic effect of BMSCs on ALI/ARDS by differentiating into AT II cells using SPC−/− mice. Furthermore, the protective effect of BMSCs-FoxM1 on lipopolysaccharide-induced endothelial cell (EC) injury was explored by detecting EC proliferation, apoptosis, scratch wounds, tube formation, permeability, and oxidative stress, and analyzing whether the Wnt/β-catenin pathway contributes to the regulatory mechanism in vitro using a pathway inhibitor.ResultsCompared with BMSCs-Vector, treatment with BMSCs-FoxM1 significantly decreased the W/D lung weight ratio, total BALF protein level, lung injury score, oxidative stress, and cytokine levels. With the detected track of BMSCs-FoxM1, we observed a low residency rate and short duration of residency in the lung. Notably, SPC was not expressed in SPC−/− mice injected with BMSCs-FoxM1. Furthermore, BMSCs-FoxM1 enhanced EC proliferation, migration, and tube formation; inhibited EC apoptosis and inflammation; and maintained vascular integrity through activation of the Wnt/β-catenin pathway, which was partially reversed by XAV-939.ConclusionOverexpression of FoxM1 enhanced the therapeutic effect of BMSCs on ARDS, possibly through a paracrine mechanism rather than by promoting BMSC differentiation into AT II cells in vivo, and prevented LPS-induced EC barrier disruption partially through activating the Wnt/β-catenin signaling pathway in vitro.

Immunotherapy strategies and prospects for acute lung injury: Focus on immune cells and cytokines.

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a disastrous condition, which can be caused by a wide range of diseases, such as pneumonia, sepsis, traumas, and the most recent, COVID-19. Even though we have gained an improved understanding of acute lung injury/acute respiratory distress syndrome pathogenesis and treatment mechanism, there is still no effective treatment for acute lung injury/acute respiratory distress syndrome, which is partly responsible for the unacceptable mortality rate. In the pathogenesis of acute lung injury, the inflammatory storm is the main pathological feature. More and more evidences show that immune cells and cytokines secreted by immune cells play an irreplaceable role in the pathogenesis of acute lung injury. Therefore, here we mainly reviewed the role of various immune cells in acute lung injury from the perspective of immunotherapy, and elaborated the crosstalk of immune cells and cytokines, aiming to provide novel ideas and targets for the treatment of acute lung injury.

Preventing acute lung injury from progressing to pulmonary fibrosis by maintaining ERS homeostasis through a multistage targeting nanomicelle

Acute lung injury / acute respiratory distress syndrome (ALI/ARDS) or pulmonary fibrosis (PF) has been regarded as a global health issue with high mortality and limited drug therapy. Clinical evidence suggests that undesired macrophage polarization (M) is the main factor driving the development of ALI/ARDS, and endoplasmic reticulum stress (ERS) has been considered an important determinant of M polarization. Accordingly, we proposed a hypothesis that restoration of ER homeostasis would effectively balance the homeostasis of M and prevent ALI from progressing to pulmonary fibrosis (PF). To this end, we designed a multistage targeted nanomicelle mainly based on hyaluronic acid (HA) and α-tocopherol succinate (α-TOS) (named as HSST or pHSST with peptide modified) to load ERS inhibitor (KIRA6, K) and anti-inflammatory drug (Dexamethasone, Dex) respectively. When inflammation occurred, K-loaded pHSST (K@pHSST) and Dex-loaded HSST (Dex@HSST) firstly achieved lung targeting by "hitchhiking" myeloid M and neutrophils (Neu) that patrol in the blood and then achieved inflammation-associated cells targeting through a CD44 receptor-ligand-mediated mode by HA. For K@pHSST, at the same time, the ER-targeting molecule (Pardaxin, Par) was used to modify the nanomicelles for tertiary ER-targeting effect and specifically delivering of the K to ER. While in response to high-level intracellular reactive oxygen species (ROS), Dex@HSST disintegrated due to the reductive α-tocopherol succinate (α-TOS) and disulfide bond. The released Dex exerted anti-inflammatory effects and promoted type 2 M cells (M2) polarization via activating intracellular glucocorticoid receptors. Through the combined administration of Dex@HSST and K@pHSST, this strategy could effectively reduce ROS, limit cytokine storm, restore ER homeostasis, reverse imbalanced M polarization, and fundamentally resolve ALI and prevent PF.

Inhalation of L-arginine-modified liposomes targeting M1 macrophages to enhance curcumin therapeutic efficacy in ALI

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS), characterized by uncontrolled lung inflammation, is one of the most devastating diseases with high morbidity and mortality. As the first line of defense system, macrophages play a crucial role in the pathogenesis of ALI/ARDS. Therefore, it has great potential to selectively target M1 macrophages to improve the therapeutic effect of anti-inflammatory drugs. l-arginine plays a key role in regulating the immune function of macrophages. The receptors mediating l-arginine uptake are highly expressed on the surface of M1-type macrophages. In this study, we designed an l-arginine-modified liposome for aerosol inhalation to target M1 macrophages in the lung, and the anti-inflammatory drug curcumin was encapsulated in liposomes as model drug. Compared with unmodified curcumin liposome (Cur-Lip), l-arginine functionalized Cur-Lip (Arg-Cur-Lip) exhibited higher uptake by M1 macrophages in vitro and higher accumulation in inflamed lungs in vivo. Furthermore, Arg-Cur-Lip showed more potent therapeutic effects in LPS-induced RAW 264.7 cells and the rat model of ALI. Overall, these findings indicate that l-arginine-modified liposomes have great potential to enhance curcumin treatment of ALI/ARDS by targeting M1 macrophages, which may provide an option for the treatment of acute lung inflammatory diseases such as coronavirus disease 2019 (COVID-19), severe acute respiratory syndrome and middle east respiratory syndrome.

Administration of Parthenolide extract (ACT001) improved autophagy and attenuate inflammatory in Rats with ARDS

IntroductionACT001 is widely used for the treatment of glioblastomas, breast cancers, and leukemic and the mechanism underlying the effect is anti-inflammatory. However, whether ACT001 has any effects on acute respiratory distress syndrome (ARDS) is not clear. ObjectivesTo investigate whether ACT001 helps to reduce mortality and pneumonedema after ARDS, and explore whether the mechanism is related to balance autophagy and inflammatory response. MethodsIn this study, a rat model based on CLP was used to explore the potency of ACT001 in ARDS. The expression of the autophagy-related protein, lung injuries, cytokines, and inflammatory-related protein was assessed. ResultsCompared with CLP group, ACT001 improved the survival rate, and lung wet-to-dry weight ratio. ACT001 activates autophagy, which is involved in the pathophysiologic process of sepsis, balancing the cytokine excessive release and lung injury in ARDS. ConclusionACT001 reduces mortality through improved autophagy and attenuates inflammation after ARDS.

Emerging roles of fibroblast growth factor 21 in critical disease.

In spite of the great progress in the management of critical diseases in recent years, its associated prevalence and mortality of multiple organ failure still remain high. As an endocrine hormone, fibroblast growth factor 21 (FGF21) functions to maintain homeostasis in the whole body. Recent studies have proved that FGF21 has promising potential effects in critical diseases. FGF21 has also been found to have a close relationship with the progression of critical diseases and has a great predictive function for organ failure. The level of FGF21 was elevated in both mouse models and human patients with sepsis or other critical illnesses. Moreover, it is a promising biomarker and has certain therapeutic roles in some critical diseases. We focus on the emerging roles of FGF21 and its potential effects in critical diseases including acute lung injury/acute respiratory distress syndrome (ALI/ARDS), acute myocardial injury (AMI), acute kidney injury (AKI), sepsis, and liver failure in this review. FGF21 has high application value and is worth further studying. Focusing on FGF21 may provide a new perspective for the management of the critical diseases.

Clinical characteristics and predictors of burn complicated with smoke inhalation injury: A retrospective analysis.

Fire smoke enters the human lungs through the respiratory tract. The damage to the respiratory tract and lung tissue is known as smoke inhalation injury (SII). Fire smoke can irritate airway epithelium cells, weaken endothelial cell adhesion and lyse alveolar type II epithelia cells, leading to emphysema, decreased lung function, pneumonia and risk of acute lung injury/acute respiratory distress syndrome (ARDS). The purpose of the present study was to analyze the clinical characteristics of patients with SII and the risk factors affecting their prognosis. A total of 103 patients with SII admitted between January 2016 to December 2021 to the Burns Unit of the Characteristic Medical Center of Chinese People's Armed Police Force and 983 Hospital of the Joint Logistics Support Force of the Chinese People's Liberation Army were selected for the present study. The demographics and clinical features between different severities of SII were analyzed. Univariate/multivariate logistic regression was used to analyze the potential predictors for severity, ARDS and mortality of patients with SII. Receiver operating characteristic (ROC) curves were used to screen independent risk factors and identify their prediction accuracy. It was concluded that total body surface area (TBSA), III burn area (of total %TBSA), cases of respiratory infections, ARDS morbidity, mortality, acute physiology and chronic health evaluation II, lung injury prediction score, lactic acid, white blood cells (WBC), alanine transaminase, blood urea nitrogen, serum creatinine and uric acid were indicators that were raised with increasing severity of SII. However red blood cells, hemoglobin, platelet count, total protein, albumin, and albumin/globulin were decreased with the increasing severity of SII (P<0.05). WBC >20.91 (109/l) was a reliable indicator for severe SII. Lactic acid >9.60 (mmol/l) demonstrated a high degree of accuracy in predicting ARDS development in patients with SII. Hemoglobin <83.00 (g/l) showed a high degree of accuracy in predicting mortality. In summary, the highlighted assessment parameters could be used to contribute to devising improved treatment plans to preempt worsening conditions (such as shock, ARDS, multiple organ dysfunction syndrome and death).

Therapeutic Targeting of NF-κB in Acute Lung Injury: A Double-Edged Sword.

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a devastating disease that can be caused by a variety of conditions including pneumonia, sepsis, trauma, and most recently, COVID-19. Although our understanding of the mechanisms of ALI/ARDS pathogenesis and resolution has considerably increased in recent years, the mortality rate remains unacceptably high (~40%), primarily due to the lack of effective therapies for ALI/ARDS. Dysregulated inflammation, as characterized by massive infiltration of polymorphonuclear leukocytes (PMNs) into the airspace and the associated damage of the capillary-alveolar barrier leading to pulmonary edema and hypoxemia, is a major hallmark of ALI/ARDS. Endothelial cells (ECs), the inner lining of blood vessels, are important cellular orchestrators of PMN infiltration in the lung. Nuclear factor-kappa B (NF-κB) plays an essential role in rendering the endothelium permissive for PMN adhesion and transmigration to reach the inflammatory site. Thus, targeting NF-κB in the endothelium provides an attractive approach to mitigate PMN-mediated vascular injury, not only in ALI/ARDS, but in other inflammatory diseases as well in which EC dysfunction is a major pathogenic mechanism. This review discusses the role and regulation of NF-κB in the context of EC inflammation and evaluates the potential and problems of targeting it as a therapy for ALI/ARDS.

Comparative study of the protective effect of Xuebijing injection and Sivelestat sodium on acute lung injury/acute respiratory distress syndrome rats

To compare the protective effect of Xuebijing injection versus Sivelestat sodium on acute lung injury/acute respiratory distress syndrome (ALI/ARDS) rats. A total of 71 male Sprague-Dawley (SD) rats were randomly divided into the blank control group (n = 8), ALI/ARDS model group (n = 21), Xuebijing injection group (n = 21) and Sivelestat sodium group (n = 21). Rats in the blank control group were injected with normal saline while the other three groups were intravenously injected 25 mg/kg lipopolysaccharide (LPS) via the tail vein to establish ALI/ARDS model. After induction of ALI/ARDS model, the blank control group and ALI/ARDS model group were given intraperitoneal injection of an equal volume of normal saline twice a day. Rats in the Xuebijing injection group were given tail vein injection of 8 mL/kg Xuebijing injection twice a day, and those in the Sivelestat sodium group were given intraperitoneal injection of 100 mg/kg Sivelestat sodium three times a day. All rats were administered continuously for five days. During the experiment, the general status of rats was observed, and the weight and survival were recorded. At the end of the experiment, bronchoalveolar lavage fluid (BALF) of rats was collected for the detection of inflammatory cells and inflammatory factors. Histopathological changes of rats lung tissue were observed. Compared with the ALI/ARDS model group, the Xuebijing injection group and Sivelestat sodium group had significantly decreased white blood cell (WBC) count and percent of neutrophil (NEU%) [WBC (×109/L): 55.86±6.68, 49.96±6.76 vs. 73.13±7.35, NEU%: 0.459±0.077, 0.315±0.047 vs. 0.709±0.067, all P < 0.05], significantly increased percent of lymphocytes (LYM%: 0.412±0.067, 0.517±0.051 vs. 0.232±0.057, both P < 0.05), and reduced interleukin-6 (IL-6) level (ng/L: 295.2±39.7, 281.9±33.1 vs. 469.6±77.0) in BALF. However, there were no significant differences in these parameters between the Xuebijing injection group and Sivelestat sodium injection group (all P > 0.05). Survival rate at the end of experiment was higher in the Xuebijing group than that in the Sivelestat sodium injection group and ALI/ARDS model group [52.4% (11/21) vs. 28.6% (6/21), 14.3% (3/21)], and survival rate at the end of experiment was higher in the Sivelestat sodium injection group than that in the ALI/ARDS model group, but the differences were not statistically significant (P > 0.05). In addition, weight and weight growth rate in the Xuebijing injection group were higher than the Sivelestat sodium group at the end of the experiment [weight (g): 217.1±6.4 vs. 207.1±7.0, weight growth rate: (-0.9±2.8)% vs. (-4.3±3.5)%], there were no significant difference between the two groups (both P > 0.05). Lung histopathology in the ALI/ARDS model group revealed high level of inflammatory exudate and inflammatory cells infiltrated in the alveoli of rats, along with damage of local alveolar epithelial cell and alveolar structure. However, these histological changes were improved in the Xuebijing injection group and in the Sivelestat sodium group. Xuebijing injection can alleviate ALI/ARDS-induced lung injury and systemic damage and improve the survival of rats by inhibiting inflammation. The protective effect of Xuebijing injection is essentially consistent with that of Sivelestat sodium.

Mechanism of high mobility group protein B1 in lipopolysaccharide-induced acute lung injury/acute respiratory distress syndrome

To investigate the role and possible pathogenesis of high mobility group protein B1 (HMGB1) in lipopolysaccharide (LPS)-induced acute lung injury/acute respiratory distress syndrome (ALI/ARDS). (1) In vivo, 24 SPFC57BL/6 male mice were randomly divided into normal control group, ALI/ARDS model group, ethyl pyruvate (EP) treatment group and EP control group, with 6 mice in each group. The ALI/ARDS model was established by intraperitoneal injection of 20 mg/kg LPS. Mice in normal control group and EP control group were intraperitoneally injected with the same amount of sterile normal saline. Then, mice in the EP treatment group and EP control group were intraperitoneally injected with 40 mg/kg HMGB1 inhibitor EP. After 6 hours, the mice were sacrificed and lung tissues were collected. The expressions of heparan sulfate (HS), syndecans-1 (SDC-1), heparanase (HPA) and matrix metalloproteinases-9 (MMP-9) in lung tissues were detected by immunofluorescence technique. Orbital blood of mice was collected and serum was extracted to detect the content of HMGB1 by enzyme linked immunosorbent assay (ELISA). (2) In vitro, human umbilical vein endothelial cells (HUVECs) were randomly divided into 6 groups: normal control group, HUVECs damage group (treated with 1 mg/L LPS for 6 hours), HMGB1 group (treated with 1 μmol/L recombinant HMGB1 for 6 hours), HMGB1+EP group (treated with recombinant HMGB1 for 1 hour and then added 1 μmol/L EP for 6 hours), LPS+EP group (treated with LPS for 1 hour and then added 1 μmol/L EP for 6 hours), EP group (treated with 1 μmol/L EP for 6 hours). The expressions of HS, SDC-1, HPA and MMP-9 in endothelial cells were detected by immunofluorescence technique. (1) In vivo, light microscopy showed that the alveolar space was thickened after LPS stimulation, and there were a large number of inflammatory cells infiltrating in the alveolar space. Compared with ALI/ARDS model group, the expressions of HS and SDC-1 in lung tissue of EP treatment group were significantly increased [HS (fluorescence intensity): 0.80±0.20 vs. 0.53±0.02, SDC-1 (fluorescence intensity): 0.72±0.02 vs. 0.51±0.01, both P < 0.05], and the expressions of HPA and MMP-9 were significantly decreased [HPA (fluorescence intensity): 2.36±0.05 vs. 3.00±0.04, MMP-9 (fluorescence intensity): 2.55±0.13 vs. 3.26±0.05, both P < 0.05]; there were no significant changes of the above indexes in EP control group. Compared with ALI/ARDS model group, the content of serum HMGB1 in EP treatment group decreased significantly (μg/L: 131.88±16.67 vs. 341.13±22.47, P < 0.05); there was no significant change in the EP control group. (2) In vitro, compared with HMGB1 group, the expressions of HS and SDC-1 in HMGB1+EP group were significantly higher [HS (fluorescence intensity): 0.83±0.07 vs. 0.56±0.03, SDC-1 (fluorescence intensity): 0.80±0.01 vs. 0.61±0.01, both P < 0.05], and the expressions of HPA and MMP-9 were significantly lower [HPA (fluorescence intensity): 1.30±0.02 vs. 2.29±0.05, MMP-9 (fluorescence intensity): 1.55±0.04 vs. 2.50±0.06, both P < 0.05]; the expression of HS, SDC-1, HPA and MMP-9 had no significant changes in EP group. HMGB1 participates in LPS-induced injury of endothelial cell glycocalyx, leading to increased lung permeability, and inhibition of HMGB1 can alleviate lung injury.

Advances in the Regulation of Macrophage Polarization by Mesenchymal Stem Cells and Implications for ALI/ARDS Treatment.

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a common condition with high mortality. ALI/ARDS is caused by multiple etiologies, and the main clinical manifestations are progressive dyspnea and intractable hypoxemia. Currently, supportive therapy is the main ALI/ARDS treatment, and there remains a lack of targeted and effective therapeutic strategies. Macrophages are important components of innate immunity. M1 macrophages are pro-inflammatory, while M2 macrophages are anti-inflammatory and promote tissue repair. Mesenchymal stem cells (MSCs) are stem cells with broad application prospects in tissue regeneration due to their multi-directional differentiation potential along with their anti-inflammatory and paracrine properties. MSCs can regulate the balance of M1/M2 macrophage polarization to improve the prognosis of ALI/ARDS. In this paper, we review the mechanisms by which MSCs regulate macrophage polarization and the signaling pathways associated with polarization. This review is expected to provide new targets for the treatment of ALI/ARDS.

Clinical efficacy of blood purification using a polymethylmethacrylate hemofilter for the treatment of severe acute pancreatitis.

BackgroundSevere acute pancreatitis (SAP) is a systemic inflammatory disease, and it can often complicate into acute kidney injury (AKI) and acute lung injury/acute respiratory distress syndrome (ALI/ARDS). This study aimed to evaluate the clinical effectiveness of blood purification using a polymethylmethacrylate (PMMA) hemofilter.MethodsWe retrospectively examined 54 patients, who were diagnosed with SAP according to the Japanese criteria from January 2011 to December 2019.ResultsOf a total of 54 SAP patients, 26 patients progressively developed AKI and required continuous hemodialysis with a PMMA membrane hemofilter (PMMA-CHD). Acute Physiology and Chronic Health Evaluation (APACHE) II score and Sequential Organ Failure Assessment (SOFA) score were significantly higher in patients requiring PMMA-CHD than in patients not requiring hemodialysis. The lung injury scores were also significantly higher in patients requiring PMMA-CHD. Of the 26 patients, 16 patients developed ALI/ARDS and required mechanical ventilation. A total of seven patients developed severe ALI/ARDS and received additional intermittent hemodiafiltration using a PMMA hemofilter (PMMA-HDF). Although the length of intensive care unit stay was significantly longer in patients with severe ALI/ARDS, blood purification therapy was discontinued in all the patients. The survival rates at the time of discharge were 92.3% and 92.9% in patients with and without PMMA-CHD, respectively. These real mortality ratios were obviously lower than the estimated mortality ratios predicted by APACHE II scores.ConclusionsThese finding suggest that the blood purification using a PMMA hemofilter would be effective for the treatment of AKI and ALI/ARDS in SAP patients.

Qingfei Litan Decoction Against Acute Lung Injury/Acute Respiratory Distress Syndrome: The Potential Roles of Anti-Inflammatory and Anti-Oxidative Effects.

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is an acute respiratory failure syndrome characterized by progressive arterial hypoxemia and dyspnea. Qingfei Litan (QFLT) decoction, as a classic prescription for the treatment of acute respiratory infections, is effective for the treatment of ALI/ARDS. In this study, the compounds, hub targets, and major pathways of QFLT in ALI/ARDS treatment were analyzed using Ultra high performance liquid chromatography coupled with mass spectrometry (UHPLC-MS) and systemic pharmacology strategies. UHPLC-MS identified 47 main components of QFLT. To explore its anti-inflammatory and anti-oxidative mechanisms, gene ontology (Go) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and network pharmacological analysis were conducted based on the main 47 components. KEGG enrichment analysis showed that TNF signaling pathway and Toll-like receptor signaling pathway may be the key pathways of ALI/ARDS. We explored the anti-inflammatory and anti-oxidative pharmacological effects of QFLT in treatment of ALI/ARDS in vivo and in vitro. QFLT suppressed the levels of proinflammatory cytokines and alleviated oxidative stress in LPS-challenged mice. In vitro, QFLT decreased the levels of TNF-α, IL-6, IL-1β secreted by LPS-activated macrophages, increased GSH level and decreased the LPS-activated reactive oxygen species (ROS) in lung epithelial A549 cells. This study suggested that QFLT may have anti-inflammatory and anti-oxidative effects on ALI/ARDS, combining in vivo and in vitro experiments with systemic pharmacology, providing a potential therapeutic strategy option.

Fudosteine attenuates acute lung injury in septic mice by inhibiting pyroptosis via the TXNIP/NLRP3/GSDMD pathway

There is a dearth of effective pharmacotherapies for sepsis-induced acute lung injury/acute respiratory distress syndrome (ALI/ARDS) to which oxidative stress and excessive inflammation are major contributors. We hypothesized that fudosteine, a cysteine derivative, may protect against sepsis-induced ALI/ARDS given its anti-oxidant capacity. This study aimed to investigate the effects and mechanisms of fudosteine in a mouse model of sepsis-induced ALI. Sepsis was induced by cecal ligation and puncture (CLP). The intragastrical administration of fudosteine (25 mg/kg, 50 mg/kg, and 100 mg/kg) dose-dependently decreased proinflammatory cytokine levels in bronchoalveolar lavage fluid (BALF) and serum and reduced BALF/serum albumin and lung wet/dry weight ratios in septic mice. The lung injury score was significantly lowered by fudosteine [e.g., 0.18 ± 0.03 (100 mg/kg) vs. 0.42 ± 0.03 (CLP), P < 0.0001]. Fudosteine also reduced the biomarkers of lung epithelial injury in BALF and markedly improved oxidative stress indicators in lung tissues [e.g., malondialdehyde: 337.70 ± 23.78 (100 mg/kg) vs. 686.40 ± 28.36 (CLP) nmol/mg protein, P < 0.0001]. Lung tissue transcriptomics analyses revealed suppressed inflammatory responses and oxidative stress with fudosteine and the involvement of the inflammasome and pyroptosis pathways. Western blot analyses indicated that fudosteine inhibited the sepsis-induced activation of gasdermin D (GSDMD) and caspase-1 and the upregulation of thioredoxin-interacting protein (TXNIP), nucleotide-binding domain, leucine-rich repeat-containing receptor, pyrin domain-containing-3 (NLRP3), and apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC). Fudosteine therefore protects against sepsis-induced ALI in mice, and the inhibition of pyroptosis via the TXNIP/NLRP3/GSDMD pathway may be an underlying mechanism.