Hexarelin modulates lung mechanics, inflammation, and fibrosis in acute lung injury

Introduction: Acute respiratory distress syndrome (ARDS) is an acute form of diffuse lung injury characterized by (i) an intense inflammatory response, (ii) increased pulmonary vascular permeability, and (iii) the loss of respiratory pulmonary tissue. In this article we explore the therapeutic potential of hexarelin, a synthetic hexapeptide growth hormone secretagogue (GHS), in an experimental model of ARDS. Hexarelin has anti-inflammatory properties and demonstrates cardiovascular-protective activities including the inhibition of cardiomyocyte apoptosis and cardiac fibrosis, both of which may involve the angiotensin-converting enzyme (ACE) system. Methods: In our experimental model, ARDS was induced by the instillation of 100 mM HCl into the right bronchus; these mice were treated with hexarelin (320 μg/kg, ip) before (Pre) or after (Post) HCl challenge, or with vehicle. Respiratory system compliance, blood gas analysis, and differential cell counts in a selective bronchoalveolar lavage (BAL) were determined 6 or 24 hours after HCl instillation. In an extended study, mice were observed for a subsequent 14 days in order to assess lung fibrosis. Results: Hexarelin induced a significant improvement in lung compliance and a reduction of the number of total immune cells in BAL 24 hours after HCl instillation, accompanied with a lower recruitment of neutrophils compared with the vehicle group. At day 14, hexarelin-treated mice presented with less pulmonary collagen deposition compared with vehicle-treated controls. Conclusions: Our data suggest that hexarelin can inhibit the early phase of the inflammatory response in a murine model of HCl-induced ARDS, thereby blunting lung remodeling processes and fibrotic development.

SARS-CoV-2 Infects Endothelial Cells In Vivo and In Vitro

SARS-CoV-2 infection can cause fatal inflammatory lung pathology, including thrombosis and increased pulmonary vascular permeability leading to edema and hemorrhage. In addition to the lung, cytokine storm-induced inflammatory cascade also affects other organs. SARS-CoV-2 infection-related vascular inflammation is characterized by endotheliopathy in the lung and other organs. Whether SARS-CoV-2 causes endotheliopathy by directly infecting endothelial cells is not known and is the focus of the present study. We observed 1) the co-localization of SARS-CoV-2 with the endothelial cell marker CD31 in the lungs of SARS-CoV-2-infected mice expressing hACE2 in the lung by intranasal delivery of adenovirus 5-hACE2 (Ad5-hACE2 mice) and non-human primates at both the protein and RNA levels, and 2) SARS-CoV-2 proteins in endothelial cells by immunogold labeling and electron microscopic analysis. We also detected the co-localization of SARS-CoV-2 with CD31 in autopsied lung tissue obtained from patients who died from severe COVID-19. Comparative analysis of RNA sequencing data of the lungs of infected Ad5-hACE2 and Ad5-empty (control) mice revealed upregulated KRAS signaling pathway, a well-known pathway for cellular activation and dysfunction. Further, we showed that SARS-CoV-2 directly infects mature mouse aortic endothelial cells (AoECs) that were activated by performing an aortic sprouting assay prior to exposure to SARS-CoV-2. This was demonstrated by co-localization of SARS-CoV-2 and CD34 by immunostaining and detection of viral particles in electron microscopic studies. Moreover, the activated AoECs became positive for ACE-2 but not quiescent AoECs. Together, our results indicate that in addition to pneumocytes, SARS-CoV-2 also directly infects mature vascular endothelial cells in vivo and ex vivo, which may contribute to cardiovascular complications in SARS-CoV-2 infection, including multipleorgan failure.

Protectin conjugates in tissue regeneration 1 restores lipopolysaccharide-induced pulmonary endothelial glycocalyx loss via ALX/SIRT1/NF-kappa B axis

Background Endothelial glycocalyx loss is integral to increased pulmonary vascular permeability in sepsis-related acute lung injury. Protectin conjugates in tissue regeneration 1 (PCTR1) is a novel macrophage-derived lipid mediator exhibiting potential anti-inflammatory and pro-resolving benefits. Methods PCTR1 was administrated intraperitoneally with 100 ng/mouse after lipopolysaccharide (LPS) challenged. Survival rate and lung function were used to evaluate the protective effects of PCTR1. Lung inflammation response was observed by morphology and inflammatory cytokines level. Endothelial glycocalyx and its related key enzymes were measured by immunofluorescence, ELISA, and Western blot. Afterward, related-pathways inhibitors were used to identify the mechanism of endothelial glycocalyx response to PCTR1 in mice and human umbilical vein endothelial cells (HUVECs) after LPS administration. Results In vivo, we show that PCTR1 protects mice against lipopolysaccharide (LPS)-induced sepsis, as shown by enhanced the survival and pulmonary function, decreased the inflammatory response in lungs and peripheral levels of inflammatory cytokines such as tumor necrosis factor-α, interleukin-6, and interleukin-1β. Moreover, PCTR1 restored lung vascular glycocalyx and reduced serum heparin sulphate (HS), syndecan-1 (SDC-1), and hyaluronic acid (HA) levels. Furthermore, we found that PCTR1 downregulated heparanase (HPA) expression to inhibit glycocalyx degradation and upregulated exostosin-1 (EXT-1) protein expression to promote glycocalyx reconstitution. Besides, we observed that BAY11-7082 blocked glycocalyx loss induced by LPS in vivo and in vitro, and BOC-2 (ALX antagonist) or EX527 (SIRT1 inhibitor) abolished the restoration of HS in response to PCTR1. Conclusion PCTR1 protects endothelial glycocalyx via ALX receptor by regulating SIRT1/NF-κB pathway, suggesting PCTR1 may be a significant therapeutic target for sepsis-related acute lung injury.

Ulinastatin as an Adjuvant Therapy to Restricting Volumes of Resuscitation Fluid Strategy for Patients with Septic Shock after Initial Management

Septic shock is the most serious complication of sepsis, leading to unacceptably high morbidity and mortality worldwide. Fluid resuscitation using crystalloids has become the mainstay of early and aggressive treatment of severe sepsis and septic shock, while increased daily fluid balances from day 2 until day 7 have been related with increased mortality. Recently, pharmacological management has been recommended to combine with appropriate fluid resuscitation for the treatment of septic shock. In this study, we compared the clinical efficacy of restricting volumes of resuscitation fluid strategy with or without intravenous infusion of ulinastatin (UTI) in treating patients with septic shock and additionally examined the patient’s changes of the extravascular lung water index (EVLWI), pulmonary vascular permeability index (PVPI), systemic vascular resistance index (SVRI), cardiac function, lactic acid (LA) level, coagulation function, and renal function. The study included 182 patients with septic shock, among which 89 patients had undergone restricting volumes of resuscitation fluid strategy with intravenous infusion of UTI and 93 patients had undergone restricting volumes of resuscitation fluid strategy alone. It was found that patients with septic shock after restricting volumes of resuscitation fluid strategy with intravenous infusion of UTI showed an increased SVRI concomitant with declined PVPI and EVLWI, increased mean artery pressure (MAP), cardiac output (CO), left ventricular ejection fraction (LVEF), stroke volume (SV), and heart rate (HR), declined levels of cardiac troponin I (cTnI), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and C-reactive protein (CRP), reduced LA level along with shortened prothrombin time (PT) and partially activated thrombin time (PATT), and decreased levels of blood urea nitrogen (BUN), creatinine (Cr), and uric acid (UA) when comparable to those after restricting volumes of resuscitation fluid strategy alone ( P < 0.05 ). We also observed fewer scores of the Acute Physiology and Chronic Health Evaluation (APACHE II) and the sequential organ failure assessment (SOFA) in patients undergoing restricting volumes of resuscitation fluid strategy with intravenous infusion of UTI than those undergoing restricting volumes of resuscitation fluid strategy alone ( P < 0.05 ). According to the above data, it is concluded that UTI as an adjuvant therapy for restricting volumes of resuscitation fluid strategy in treating septic shock may decrease the LA level, attenuate the inflammatory response, reduce vascular permeability, prevent pulmonary edema, and restore cardiac and renal functions.

BMSC-Derived Exosomes Ameliorate LPS-Induced Acute Lung Injury by miR-384-5p-Controlled Alveolar Macrophage Autophagy

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are common critical diseases. Bone marrow mesenchymal stem cell (BMSC) transplantation is previously shown to effectively rescue injured lung tissues. The therapeutic mechanism of BMSC-derived exosomes is not fully understood. Here, we investigated the BMSC-derived exosomal microRNAs (miRNAs) on effecting lipopolysaccharide- (LPS-) induced ALI and its mechanism. In vitro, rat alveolar macrophages were treated with or without exosomes in the presence of 10 μg/ml LPS for 24 h. Cell viability was determined with Cell Counting Kit-8 assay. Apoptotic ratio was determined with TUNEL and Annexin V-FITC/PI double staining. The levels of miR-384-5p and autophagy-associated genes were measured by RT-qPCR and western blot. Autophagy was observed by TEM and assessed by means of the mRFP-GFP-LC3 adenovirus transfection assay. In vivo, we constructed LPS-induced ALI rat models. Exosomes were injected into rats via the caudal vein or trachea 4 h later after LPS treatment. The lung histological pathology was determined by H&E staining. Pulmonary vascular permeability was assessed by wet-to-dry weight ratio and Evans blue dye leakage assay, and inflammatory cytokines in serum and BALF were measured by ELISA. Furthermore, the therapeutic mechanism involved in miR-384-5p and Beclin-1 was determined. The results showed that BMSC-derived exosomes were taken up by the alveolar macrophages and attenuated LPS-induced alveolar macrophage viability loss and apoptosis. Exosomes effectively improved the survival rate of ALI rats within 7 days, which was associated with alleviating lung pathological changes and pulmonary vascular permeability and attenuating inflammatory response. Furthermore, this study for the first time found that miR-384-5p was enriched in BMSC-derived exosomes, and exosomal miR-384-5p resulted in relieving LPS-injured autophagy disorder in alveolar macrophages by targeting Beclin-1. Therefore, exosomal miR-384-5p could be demonstrated as a promising therapeutic strategy for ALI/ARDS.

COVID-19 ARDS is characterized by higher extravascular lung water than non-COVID-19 ARDS: the PiCCOVID study

Background In acute respiratory distress syndrome (ARDS), extravascular lung water index (EVLWi) and pulmonary vascular permeability index (PVPI) measured by transpulmonary thermodilution reflect the degree of lung injury. Whether EVLWi and PVPI are different between non-COVID-19 ARDS and the ARDS due to COVID-19 has never been reported. We aimed at comparing EVLWi, PVPI, respiratory mechanics and hemodynamics in patients with COVID-19 ARDS vs. ARDS of other origin. Methods Between March and October 2020, in an observational study conducted in intensive care units from three university hospitals, 60 patients with COVID-19-related ARDS monitored by transpulmonary thermodilution were compared to the 60 consecutive non-COVID-19 ARDS admitted immediately before the COVID-19 outbreak between December 2018 and February 2020. Results Driving pressure was similar between patients with COVID-19 and non-COVID-19 ARDS, at baseline as well as during the study period. Compared to patients without COVID-19, those with COVID-19 exhibited higher EVLWi, both at the baseline (17 (14–21) vs. 15 (11–19) mL/kg, respectively, p = 0.03) and at the time of its maximal value (24 (18–27) vs. 21 (15–24) mL/kg, respectively, p = 0.01). Similar results were observed for PVPI. In COVID-19 patients, the worst ratio between arterial oxygen partial pressure over oxygen inspired fraction was lower (81 (70–109) vs. 100 (80–124) mmHg, respectively, p = 0.02) and prone positioning and extracorporeal membrane oxygenation (ECMO) were more frequently used than in patients without COVID-19. COVID-19 patients had lower maximal lactate level and maximal norepinephrine dose than patients without COVID-19. Day-60 mortality was similar between groups (57% vs. 65%, respectively, p = 0.45). The maximal value of EVLWi and PVPI remained independently associated with outcome in the whole cohort. Conclusion Compared to ARDS patients without COVID-19, patients with COVID-19 had similar lung mechanics, but higher EVLWi and PVPI values from the beginning of the disease. This was associated with worse oxygenation and with more requirement of prone positioning and ECMO. This is compatible with the specific lung inflammation and severe diffuse alveolar damage related to COVID-19. By contrast, patients with COVID-19 had fewer hemodynamic derangement. Eventually, mortality was similar between groups. Trial registration number and date of registration ClinicalTrials.gov (NCT04337983). Registered 30 March 2020—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04337983.

Increased extravascular lung water index (EVLWI) reflects rapid non-cardiogenic oedema and mortality in COVID-19 associated ARDS

Nearly 5% of patients suffering from COVID-19 develop acute respiratory distress syndrome (ARDS). Extravascular lung water index (EVLWI) is a marker of pulmonary oedema which is associated with mortality in ARDS. In this study, we evaluate whether EVLWI is higher in patients with COVID-19 associated ARDS as compared to COVID-19 negative, ventilated patients with ARDS and whether EVLWI has the potential to monitor disease progression. EVLWI and cardiac function were monitored by transpulmonary thermodilution in 25 patients with COVID-19 ARDS subsequent to intubation and compared to a control group of 49 non-COVID-19 ARDS patients. At intubation, EVLWI was noticeably elevated and significantly higher in COVID-19 patients than in the control group (17 (11–38) vs. 11 (6–26) mL/kg; p < 0.001). High pulmonary vascular permeability index values (2.9 (1.0–5.2) versus 1.9 (1.0–5.2); p = 0.003) suggested a non-cardiogenic pulmonary oedema. By contrast, the cardiac parameters SVI, GEF and GEDVI were comparable in both cohorts. High EVLWI values were associated with viral persistence, prolonged intensive care treatment and in-hospital mortality (23.2 ± 6.7% vs. 30.3 ± 6.0%, p = 0.025). Also, EVLWI showed a significant between-subjects (r = − 0.60; p = 0.001) and within-subjects correlation (r = − 0.27; p = 0.028) to Horowitz index. Compared to non COVID-19 ARDS, COVID-19 results in markedly elevated EVLWI-values in patients with ARDS. High EVLWI reflects a non-cardiogenic pulmonary oedema in COVID-19 ARDS and could serve as parameter to monitor ARDS progression on ICU.

Sodium houttuyfonate relieves acute lung injury by nano micellar carrier and inhibits mitogen-activated protein kinase and nuclear factor kappa-B activation in mice

Acute lung injury (ALI) is characterized by increased pulmonary vascular permeability in response to the accumulation of inflammatory cells, release of inflammatory cytokines, and activated oxidative stress. The present study was performed to investigate the effect of sodium houttuyfonate (SH), an extract of Houttuynia cordata, on inflammatory response and oxidative stress in ALI induced by lipopolysaccharides (LPS). Male C57BL/6 mice were randomly allocated to control, LPS, dimethyl sulfoxide (DMSO), and SH groups. The ALI model was established by intratracheal LPS injection. Lung tissue was collected 6 h after LPS injection for histopathological analysis, measurement of wet-to-dry ratio, myeloperoxidase (MPO) and oxidative stress levels, and the p38, jun N-terminal kinase (JNK), extracellular regulated kinase (ERK), and p65 phosphorylation levels. Bronchoalveolar fluid (BALF) was collected for the detection of protein concentration, MPO and cytokine levels. The histopathological test showed that SH significantly alleviates damage to pulmonary tissue. Improved vascular permeability was indicated by reduced BALF protein level and lung wet-to-dry ratio in the SH group. MPO levels were decreased in lung tissue and BALF. Oxidative stress and inflammatory responses were inhibited by SH, as indicated by MDA, SOD and cytokine levels. The MAPK and NF-KB pathways were inhibited as shown by the attenuated phosphorylation of p38, JNK, ERK and p65. Sodium houttuyfonate exhibited a protective role against LPS-induced lung injury through anti-oxidative and anti-inflammatory effects. The MAPK and NF-K B pathways may be inhibited by sodium houttuyfonate. Sodium Houttuynin has a good effect on a variety of acute infectious diseases, but its solubility and stability are insufficient, which limits its efficacy. Nano delivery system can enhance the effective ingredients of traditional Chinese medicine, reduce the toxic and side effects of drugs, and improve their medicinal properties. Therefore, this paper adopts nano delivery system to assist drug use and improve research efficiency.

Sesquiterpene Lactone Deoxyelephantopin Isolated from Elephantopus scaber and Its Derivative DETD-35 Suppress BRAFV600E Mutant Melanoma Lung Metastasis in Mice

Melanoma is a highly metastatic disease with an increasing rate of incidence worldwide. It is treatment refractory and has poor clinical prognosis; therefore, the development of new therapeutic agents for metastatic melanoma are urgently required. In this study, we created a lung-seeking A375LM5IF4g/Luc BRAFV600E mutant melanoma cell clone and investigated the bioefficacy of a plant sesquiterpene lactone deoxyelephantopin (DET) and its novel semi-synthetic derivative, DETD-35, in suppressing metastatic A375LM5IF4g/Luc melanoma growth in vitro and in a xenograft mouse model. DET and DETD-35 treatment inhibited A375LM5IF4g/Luc cell proliferation, and induced G2/M cell-cycle arrest and apoptosis. Furthermore, A375LM5IF4g/Luc exhibited clonogenic, metastatic and invasive abilities, and several A375LM5IF4g/Luc metastasis markers, N-cadherin, MMP2, vimentin and integrin α4 were significantly suppressed by treatment with either compound. Interestingly, DET- and DETD-35-induced Reactive Oxygen Species (ROS) generation and glutathione (GSH) depletion were found to be upstream events important for the in vitro activities, because exogenous GSH supplementation blunted DET and DETD-35 effects on A375LM5IF4g/Luc cells. DET and DETD-35 also induced mitochondrial DNA mutation, superoxide production, mitochondrial bioenergetics dysfunction, and mitochondrial protein deregulation. Most importantly, DET and DETD-35 inhibited lung metastasis of A375LM5IF4g/Luc in NOD/SCID mice through inhibiting pulmonary vascular permeability and melanoma cell (Mel-A+) proliferation, angiogenesis (VEGF+, CD31+) and EMT (N-cadherin) in the tumor microenvironment in the lungs. These findings indicate that DET and DETD-35 may be useful in the intervention of lung metastatic BRAFV600E mutant melanoma.

Prognostic Significance of Plasma Hepatocyte Growth Factor in Sepsis

Background: To assess any correlation of plasma hepatocyte growth factor (HGF) levels with relevant endothelial cell injury parameters and determine the prognostic value in septic patients. Methods: A prospective, observational study was conducted in patients with sepsis admitted to the Department of Critical Care Medicine at the Zhongda Hospital from November 2017 to March 2018. Plasma HGF levels were measured by enzyme-linked immunosorbent assay in the first 24 h after admission (day 1) and on day 3. The primary endpoint was defined as all-cause 28-day mortality. Furthermore, we analyzed the correlation of HGF with relevant endothelial cell injury markers. Results: Eighty-six patients admitted with sepsis were included. HGF levels of nonsurvivors were elevated compared to those of survivors on day 1 (1940.62 ± 74.66 pg/mL vs. 1635.61 ± 47.49 pg/mL; P = 0.002) and day 3 (1824.82 ± 137.52 pg/mL vs. 1309.77 ± 83.49 pg/mL; P = 0.001) and showed a strong correlation with von Willebrand factor (r = 0.45, P < 0.0001), lactate (r = 0.35, P = 0.0011), pulmonary vascular permeability index (r = 0.38, P = 0.0241), first 24 h fluid administration (r = 0.38, P < 0.0001), and sequential organ failure assessment score (r = 0.40, P = 0.0001). Plasma HGF levels were able to prognostically discriminate between survivors and nonsurvivors on day 1 (AUC: 0.72, 95%CI: 0.60-0.84) and day 3 (AUC: 0.77, 95%CI: 0.63-0.91). Conclusions: HGF levels are associated with sepsis and correlated with established markers of endothelial cell injury. Elevated HGF levels in sepsis patients are an efficient indicator of poor prognosis. Trial registration: The study was registered in Clinical Trial (Registration Number: NCT02883231).