Acadesine alleviates acute pancreatitis-related lung injury by mediating the barrier protective function of pulmonary microvascular endothelial cells

Acute respiratory distress syndrome (ARDS): from mechanistic insights to therapeutic strategies

Acute respiratory distress syndrome (ARDS) is a clinical syndrome of acute hypoxic respiratory failure caused by diffuse lung inflammation and edema. ARDS can be precipitated by intrapulmonary factors or extrapulmonary factors, which can lead to severe hypoxemia. Patients suffering from ARDS have high mortality rates, including a 28-day mortality rate of 34.8% and an overall in-hospital mortality rate of 40.0%. The pathophysiology of ARDS is complex and involves the activation and dysregulation of multiple overlapping and interacting pathways of systemic inflammation and coagulation, including the respiratory system, circulatory system, and immune system. In general, the treatment of inflammatory injuries is a coordinated process that involves the downregulation of proinflammatory pathways and the upregulation of anti-inflammatory pathways. Given the complexity of the underlying disease, treatment needs to be tailored to the problem. Hence, we discuss the pathogenesis and treatment methods of affected organs, including 2019 coronavirus disease (COVID-19)-related pneumonia, drowning, trauma, blood transfusion, severe acute pancreatitis, and sepsis. This review is intended to provide a new perspective concerning ARDS and offer novel insight into future therapeutic interventions.

Rhein Mitigates Lung Injury in Severe Acute Pancreatitis Through the Inhibition of MARK4-Mediated Microtubule Destabilization

Purpose

Explore the therapeutic effect and molecular mechanism of rhein on severe acute pancreatitis associated acute lung injury (SAP-ALI).

Methods

The SAP-ALI rat model was constructed by retrograde injection of 5% sodium taurocholate into the pancreaticobiliary duct, and pulmonary microvascular endothelial cell (PMVEC) injury model was induced by LPS. The potential therapeutic effects and appropriate dosages of rhein on SAP-ALI and PMVEC were investigated in both in vivo and in vitro experiments. Furthermore, the regulatory role of MARK4 in the related pathological process were confirmed by some experimental methods. RNA sequencing analysis was performed to explore the potential downstream genes of MARK4. Moreover, the regulatory effect of rhein on MARK4 was validated through molecular docking and rescue experiments.

Results

Rhein intervention had potential therapeutic effects on acute lung injury triggered by SAP and pulmonary endothelial cell injury induced by LPS. MARK4 may contribute to pulmonary endothelial cell injury through the modulation of microtubule structure. Compared with LPS stimulation, a total of 2081 differentially expressed genes were identified after MARK4 knockdown. The results of molecular docking and rescue experiments indicated that rhein may exert its protective effects by targeting MARK4.

Conclusion

Rhein may regulate the microtubule structure by targeting MARK4, thereby alleviating SAP-ALI and LPS-induced pulmonary endothelial cell injury.

The endothelial activation and stress index is a potential prognostic indicator for patients with acute pancreatitis managed in the intensive care unit: a retrospective study

Background

The endothelial activation and stress index (EASIX) serves as a dependable and efficient surrogate marker for endothelial dysfunction, which plays an essential role in the pathophysiology of acute pancreatitis (AP). Hence, we investigated the prognostic value of EASIX in AP.

Methods

This was a retrospective study, using patient information obtained from the Medical Information Market for Intensive Care-IV (MIMIC-IV) database. EASIX was calculated using lactate dehydrogenase, serum creatinine, and platelet counts obtained during the first measurement within 24 h of admission. Patients were grouped into three cohorts based on log2-transformed EASIX. The main endpoint of the study was 28-day all-cause mortality (ACM) in AP patients, with the secondary endpoint being 90-day ACM. The relationship between EASIX and prognosis in patients with AP was evaluated using Cox proportional hazards models, Kaplan-Meier curves, restricted cubic spline (RCS) curves, and subgroup analyses. Receiver operating characteristic (ROC) curves were constructed to evaluate the predictive performance of EASIX compared to other indicators.

Results

The study cohort comprised 620 patients in total. Multivariate Cox proportional hazards analysis indicated that an increased log2 (EASIX) was linked to a higher risk of 28-day ACM in AP patients (HR, 1.32; 95% CI: 1.14-1.52; p < 0.001). The risk of 28-day ACM was higher in Tertiles 2 and 3 compared with Tertile 1 [(HR, 2.80; 95% CI: 1.21-6.45); (HR, 3.50; 95% CI: 1.42-8.66)]. Comparable findings were noted for 90-day ACM. Kaplan-Meier curves demonstrated that patients with elevated log2 (EASIX) had lower 28- and 90-day survival rates. The RCS curves suggested a non-linear relationship between log2 (EASIX) and 28- and 90-day ACM. ROC curves indicated that log2 (EASIX) was not inferior to sequential organ failure assessment and systemic inflammatory response syndrome scores in predicting the prognosis of patients with AP. Subgroup analyses demonstrated no interaction between log2 (EASIX) and any subgroup.

Conclusion

Elevated EASIX levels were significantly correlated with a heightened risk of 28- and 90-day ACM in AP patients.

Effect of atorvastatin on lipopolysaccharide-induced lung inflammation and hypoxia in mice; modulation of HIF-1α, CINC and MIP-2

BACKGROUND

Acute lung injury is a crucial pathological state, particularly in some severe infectious respiratory illnesses, distinguished by acute inflammation, pulmonary edema, hypoxia, and neutrophil recruitment. Cytokine-induced neutrophil chemoattractant (CINC) and macrophage inflammatory protein-2 (MIP-2) play a vital role in neutrophil recruitment.

OBJECTIVE

Here, we validated the potential repressing effect of atorvastatin on acute lung injury induced by lipopolysaccharide (LPS) in mice.

MATERIALS AND METHODS

Mice were injected with LPS (250 μg/kg; i.p.) daily for 7 days, and atorvastatin (25 and 50 mg/kg; orally) daily along with LPS.

RESULTS

Atorvastatin ameliorated oxidative stress as evidenced by increased reduced glutathione (GSH) and nuclear factor-erythroid 2 related factor 2 (Nrf2) levels and decreased malondialdehyde (MDA) levels. Additionally, it lessened inflammatory biomarkers including tumor necrosis factor-alpha (TNF-α), mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), CINC, and MIP-2, as well as hypoxia biomarker hypoxia-inducible factor-1α (HIF-1α). Moreover, atorvastatin slowed the progression of lung tissue histological lesions.

CONCLUSION

Collectively, the present study suggests that, atorvastatin effectively protects against LPS-induced acute lung injury through inhibition of oxidative stress, inflammation, hypoxia, and neutrophil recruitment.

Inhibition of aquaporin-9 ameliorates severe acute pancreatitis and associated lung injury by NLRP3 and Nrf2/HO-1 pathways

Inflammation, apoptosis and oxidative stress play crucial roles in the deterioration of severe acute pancreatitis-associated acute respiratory distress syndrome (SAP-ARDS). Unfortunately, despite a high mortality rate of 45 %[1], there are limited treatment options available for ARDS outside of last resort options such as mechanical ventilation and extracorporeal support strategies[2]. This study investigated the potential therapeutic role and mechanisms of AQP9 inhibitor RG100204 in two animal models of severe acute pancreatitis, inducing acute respiratory distress syndrome: 1) a sodium-taurocholate induced rat model, and 2) and Cerulein and lipopolysaccharide induced mouse model. RG100204 treatment led to a profound reduction in inflammatory cytokine expression in pancreatic, and lung tissue, in both models. In addition, infiltration of CD68 + and CD11b + cells into these tissues were reduced in RG100204 treated SAP animals, and edema and SAP associated tissue damage were improved. Moreover, we demonstrate that RG100204 reduced apoptosis in the lungs of rat SAP animals, and reduces NF-κB signaling, NLRP3, expression, while profoundly increasing the Nrf2-dependent anti oxidative stress response. We conclude that AQP9 inhibition is a promising strategy for the treatment of pancreatitis and its systemic complications, such as ARDS.

Targeting the AMPK/Nrf2 Pathway: A Novel Therapeutic Approach for Acute Lung Injury

ALI(acute lung injury) is a severe respiratory dysfunction caused by various intrapulmonary and extrapulmonary factors. It is primarily characterized by oxidative stress and affects the integrity of the pulmonary barrier. In severe cases, ALI can progress to ARDS(acute respiratory distress syndrome), a condition that poses a serious threat to the lives of affected patients. To date, the etiological mechanisms underlying ALI remain elusive, and available therapeutic options are quite limited. AMPK(AMP-activated protein kinase), an essential serine/threonine protein kinase, performs a pivotal function in the regulation of cellular energy levels and cellular regulatory mechanisms, including the detection of redox signals and mitigating oxidative stress. Meanwhile, Nrf2(nuclear factor erythroid 2-related factor 2), a critical transcription factor, alleviates inflammation and oxidative responses by interacting with multiple signaling pathways and contributing to the modulation of oxidative enzymes associated with inflammation and programmed cell death. Indeed, AMPK induces the dissociation of Nrf2 from Keap1(kelch-like ECH-associated protein-1) and facilitates its translocation into the nucleus to trigger the transcription of downstream antioxidant genes, ultimately suppressing the expression of inflammatory cells in the lungs. Given their roles, AMPK and Nrf2 hold promise as novel treatment targets for ALI. This study aimed to summarise the current status of research on the AMPK/Nrf2 signaling pathway in ALI, encompassing recently reported natural compounds and drugs that can activate the AMPK/Nrf2 signaling pathway to alleviate lung injury, and provide a theoretical reference for early intervention in lung injury and future research on lung protection.

Hibifolin protected pro-inflammatory response and oxidative stress in LPS-induced acute lung injury through antioxidative enzymes and the AMPK2/Nrf-2 pathway

ALI is a grave medical ailment that manifests as abrupt inflammation of the lungs and diminished oxygen levels. It poses a considerable challenge to the medical fraternity, with elevated rates of morbidity and mortality. Our research endeavors to investigate the potential of hibifolin, a flavonoid glucuronide, imbued with potent antioxidant properties, and its molecular mechanism to combat LPS-induced ALI in mice. The study utilized ICR mice to create an ALI model induced by LPS. Prior to LPS administration, hibifolin was given at 10, 30, or 50 mg/kg, or dexamethasone was given at 1 mg/kg to assess its preventative impact. Changes in lung tissue, pulmonary edema, and lipid peroxidation were analyzed using H&E stain assay, lung wet/dry ratio assay, and MDA formation assay, respectively. Activity assay kits were used to measure MPO activity and antioxidative enzymes (SOD, CAT, GPx) activity in the lungs. Western blot assay was used to determine the phosphorylation of Nrf-2 and AMPK2 in the lungs. Hibifolin demonstrated a concentration-dependent improvement in LPS-induced histopathologic pulmonary changes. This treatment notably mitigated pulmonary edema, lipid peroxidation, and MPO activity in ALI mice. Additionally, hibifolin successfully restored antioxidative enzyme activity in the lungs of ALI mice. Moreover, hibifolin effectively promoted Nrf-2 phosphorylation and reinstated AMPK2 phosphorylation in the lungs of ALI mice. The results indicate that hibifolin could effectively alleviate the pathophysiological impact of LPS-induced ALI. This is likely due to its antioxidative properties, which help to restore antioxidative enzyme activity and activate the AMPK2/Nrf2 pathway. These findings are valuable in terms of enhancing our knowledge of ALI treatment and pave the way for further investigation into hibifolin as a potential therapeutic option for lung injuries.

Intestinal Mucosal Immune Barrier: A Powerful Firewall Against Severe Acute Pancreatitis-Associated Acute Lung Injury via the Gut-Lung Axis

The pathogenesis of severe acute pancreatitis-associated acute lung injury (SAP-ALI), which is the leading cause of mortality among hospitalized patients in the intensive care unit, remains incompletely elucidated. The intestinal mucosal immune barrier is a crucial component of the intestinal epithelial barrier, and its aberrant activation contributes to the induction of sustained pro-inflammatory immune responses, paradoxical intercellular communication, and bacterial translocation. In this review, we firstly provide a comprehensive overview of the composition of the intestinal mucosal immune barrier and its pivotal roles in the pathogenesis of SAP-ALI. Secondly, the mechanisms of its crosstalk with gut microbiota, which is called gut-lung axis, and its effect on SAP-ALI were summarized. Finally, a number of drugs that could enhance the intestinal mucosal immune barrier and exhibit potential anti-SAP-ALI activities were presented, including probiotics, glutamine, enteral nutrition, and traditional Chinese medicine (TCM). The aim is to offer a theoretical framework based on the perspective of the intestinal mucosal immune barrier to protect against SAP-ALI.

Extracellular Vesicle ITGAM and ITGB2 Mediate Severe Acute Pancreatitis-Related Acute Lung Injury

Integrins expressed on extracellular vesicles (EVs) secreted by various cancers are reported to mediate the organotropism of these EVs. Our previous experiment found that pancreatic tissue of mice with severe cases of acute pancreatitis (SAP) overexpresses several integrins and that serum EVs of these mice (SAP-EVs) can mediate acute lung injury (ALI). It is unclear if SAP-EV express integrins that can promote their accumulation in the lung to promote ALI. Here, we report that SAP-EV overexpress several integrins and that preincubation of SAP-EV with the integrin antagonist peptide HYD-1 markedly attenuates their pulmonary inflammation and disrupt the pulmonary microvascular endothelial cell (PMVEC) barrier. Further, we report that injecting SAP mice with EVs engineered to overexpress two of these integrins (ITGAM and ITGB2) can attenuate the pulmonary accumulation of pancreas-derived EVs and similarly decrease pulmonary inflammation and disruption of the endothelial cell barrier. Based on these findings, we propose that pancreatic EVs can mediate ALI in SAP patients and that this injury response could be attenuated by administering EVs that overexpress ITGAM and/or ITGB2, which is worthy of further study due to the lack of effective therapies for SAP-induced ALI.