Degree Of Lung Injury Research Articles

ROLE OF CASPASE-1/CASPASE-11-HMGB1-RAGE/TLR4 SIGNALING IN THE EXACERBATION OF EXTRAPULMONARY SEPSIS INDUCED LUNG INJURY BY MECHANICAL VENTILATION.

Mechanical ventilation (MV) is a clinically important measure for respiratory support in critically ill patients. Although moderate tidal volume MV does not cause lung injury, it can further exacerbate lung injury in pathological state such as sepsis. This pathological process is known as the 'two-hit' theory, whereby an initial lung injury (e.g., infection, trauma, or sepsis) triggers an inflammatory response that activates immune cells, presenting the lung tissue in a fragile state and rendering it more susceptible to subsequent injury. The second hit occurs when mechanical ventilation is applied to lung tissue in a fragile state, and it is noteworthy that this mechanical ventilation is harmless to healthy lung tissue, further aggravating pre-existing lung injury through unknown mechanisms. This interaction between initial injury and subsequent mechanical ventilation develops a malignant cycle significantly exacerbating lung injury and severely hampering patient prognosis. The two-hit theory is critical to understanding the complicated mechanisms of ventilator-associated lung injury and facilitates the subsequent development of targeted therapeutic strategies. CLP mice model was used to mimic clinical sepsis patients. After 12 hours the mice were mechanical ventilated for 2-6 hours. MV by itself didn't lead to HMGB1 release, but significantly strengthened HMGB1 in plasma and cytoplasm of lung tissue in septic mice. Plasma and lung tissue activation of cytokines and chemokines, MAPK signaling pathway, neutrophil recruitment, and ALI were progressively decreased in LysM HMGB1-/- (Hmgb1 deletion in myeloid cells) and iHMGB1-/- mice (inducible HMGB1-/- mouse strain where the Hmgb1 gene was globally deleted after tamoxifen treatment). Compared with C57BL/6 mice, although EC-HMGB1-/- (Hmgb1 deletion in endothelial cells) mice didn't have lower levels of inflammation, neutrophil recruitment and lung injury were reduced. Compared with LysM HMGB1-/- mice, EC-HMGB1-/- mice had higher levels of inflammation but significantly lower neutrophil recruitment and lung injury. Overall, iHMGB1-/- mice had the lowest levels of all the above indicators. The level of inflammation, neutrophil recruitment and the degree of lung injury were decreased in RAGE-/- mice, and even the above indices were further decreased in TLR4/RAGE-/- mice. Levels of inflammation and neutrophil recruitment were decreased in Caspase-11-/- and Caspase-1/11-/- mice, but no statistical difference between these two gene knockout mice. These data show for the first time that the Caspase-1/Caspase-11-HMGB1-TLR4/RAGE signaling pathway plays a key role in mice model of sepsis induced lung injury exacerbated by MV. Different species of HMGB1 knockout mice have different lung protective mechanisms in the 'two hits' model, and location is the key to function. Specifically, LysM HMGB1-/- mice due to the deletion of HMGB1 in myeloid cells resulted in a pulmonary protective mechanism that was associated with a downregulation of the inflammatory response. EC HMGB1-/- mice are deficient in HMGB1 owing to endothelial cells, resulting in a distinct pulmonary protective mechanism independent of the inflammatory response and more relevant to the improvement of alveolar-capillary permeability. iHMGB1-/- mice, which are systemically HMGB1-deficient, share both of these lung-protective mechanisms.

Histological Scoring Systems for the Assessment of the Degree of Lung Injury in Rats

Acute respiratory distress syndrome (ARDS) is a serious pulmonary reaction with well-defined clinical parameters in humans triggered by many causes besides bacterial and viral pneumonia. However, there is no definitive definition of ARDS parameters in the experimental animal model. With its 2010 workshop report, the American Thoracic Society defined the main histopathological features that determine the presence of ARDS in laboratory animals, such as changes in parenchymal tissue, altered integrity of the alveolar capillary barrier, inflammation, and abnormal lung function. Understanding these parameters, scoring tissue lesions is used to convert observational pathological data into semi-quantitative or quantitative data for statistical analysis and improved precision.

Assessment of Autoregulation of the Cerebral Circulation during Acute Lung Injury in a Neonatal Porcine Model.

In neonates with acute lung injury (ALI), targeting lower oxygenation saturations is suggested to limit oxygen toxicity while maintaining vital organ function. Although thresholds for cerebral autoregulation are studied for the management of premature infants, the impact of hypoxia on hemodynamics, tissue oxygen consumption and extraction is not well understood in term infants with ALI. We examined hemodynamics, cerebral autoregulation and fractional oxygen extraction, as measured by near-infrared spectroscopy (NIRS) and blood gases, in a neonatal porcine oleic acid injury model of moderate ALI. We hypothesized that in ALI animals, cerebral oxygen extraction would be increased to a greater degree than kidney or gut oxygen extraction as indicative of the brain's adaptive efforts to increase cerebral oxygen extraction at the expense of splanchnic end organs. Fifteen anesthetized, ventilated 5-day-old neonatal piglets were divided into moderate lung injury by treatment with oleic acid or control (sham injection). The degree of lung injury was quantified at baseline and after establishment of ALI by blood gases, ventilation parameters and calculated oxygenation deficit, hemodynamic indices by echocardiography and lung injury score by ultrasound. PaCO2 was maintained constant during ventilation. Cerebral, renal and gut oxygenation was determined by NIRS during stepwise decreases in inspired oxygen from 50% to 21%, correlated with PaO2 and PvO2; changes in fractional oxygen extraction (ΔFOE) were calculated from NIRS and from regional blood gas samples. The proportion of cerebral autoregulation impairment attributable to blood pressure, and to hypoxemia, was calculated from autoregulation nomograms. ALI manifested as hypoxemia with increasing intrapulmonary shunt fraction, decreased lung compliance and increased resistance, and marked increase in lung ultrasound score. Brain, gut and renal NIRS, obtained from probes placed over the anterior skull, central abdomen and flank, respectively, correlated with concurrent SVC (brain) or IVC (gut, renal) PvO2 and SvO2. Cerebral autoregulation was impaired after ALI as a function of blood pressure at all FiO2 steps, but predominantly by hypoxemia at FiO2 < 40%. Cerebral ΔFOE was higher in ALI animals at all FiO2 steps. We conclude that in an animal model of neonatal ALI, cerebrovascular blood flow regulation is primarily dependent on oxygenation. There is not a defined oxygenation threshold below which cerebral autoregulation is impaired in ALI. Cerebral oxygen extraction is enhanced in ALI, reflecting compensation for exhausted cerebral autoregulation due to the degree of hypoxemia and/or hypotension, thereby protecting against tissue hypoxia.

Paeoniflorin attenuates particulate matter-induced acute lung injury by inhibiting oxidative stress and NLRP3 inflammasome-mediated pyroptosis through activation of the Nrf2 signaling pathway

Particulate matter (PM), the main component of air pollutants, emerges as a research hotspot, especially in the area of respiratory diseases. Paeoniflorin (PAE), known as anti-inflammatory and immunomodulatory effects, has been reported to alleviate acute lung injury (ALI). However, the effect of PAE on PM-induced ALI and the underlying mechanisms are still unclear yet. In this study, we established the PM-induced ALI model using C57BL/6J mice and BEAS-2B cells to explore the function of PAE. In vivo, mice were intraperitoneally injected with PAE (100 mg/kg) or saline 1 h before instilled with 4 mg/kg PM intratracheally and were euthanized on the third day. For lung tissues, HE staining and TUNEL staining were used to evaluate the degree of lung injury, ELISA assay was used to assess inflammatory mediators and oxidative stress level, Immunofluorescence staining and western blotting were applied to explore the role of pyroptosis and Nrf2 signaling pathway. In vitro, BEAS-2B cells were pretreated with 100 μM PAE before exposure to 200 μg/ml PM and were collected after 24h for the subsequent experiments. TUNEL staining, ROS staining, and western blotting were conducted to explore the underlying mechanisms of PAE on PM-induced ALI. According to the results, PAE can attenuate the degree of PM-induced ALI in mice and reduce PM-induced cytotoxicity in BEAS-2B cells. PAE can relieve PM-induced excessive oxidative stress and NLRP3 inflammasome-mediated pyroptosis. Additionally, PAE can also activate Nrf2 signaling pathway and inhibition of Nrf2 signaling pathway can impair the protective effect of PAE by aggravating oxidative stress and pyroptosis. Our findings demonstrate that PAE can attenuate PM-induced ALI by inhibiting oxidative stress and NLRP3 inflammasome-mediated pyroptosis, which is mediated by Nrf2 signaling pathway.

Syringic acid attenuates acute lung injury by modulating macrophage polarization in LPS-induced mice

BackgroundAcute lung injury (ALI) is a continuum of lung changes caused by multiple lung injuries, characterized by a syndrome of uncontrolled systemic inflammation that often leads to significant morbidity and death. Anti-inflammatory is one of its treatment methods, but there is no safe and available drug therapy. Syringic acid (SA) is a natural organic compound commonly found in a variety of plants, especially in certain woody plants and fruits. In modern pharmacological studies, SA has anti-inflammatory effects and therefore may be a potentially safe and available compound for the treatment of acute lung injury. PurposeThis study attempts to reveal the protective mechanism of SA against ALI by affecting the polarization of macrophages and the activation of NF-κB signaling pathway. Trying to find a safer and more effective drug therapy for clinical use. MethodsWe constructed the ALI model using C57BL/6 mice by intratracheal instillation of LPS (10 mg/kg). Histological analysis was performed with hematoxylin and eosin (H&E). The wet-dry ratio of the whole lung was measured to evaluate pulmonary edema. The effect of SA on macrophage M1-type was detected by flow cytometry. BCA protein quantification method was used to determine the total protein concentration in bronchoalveolar lavage fluid (BALF). The levels of Interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α in BALF were determined by the ELISA kits, and RT-qPCR was used to detect the expression levels of IL-6, IL-1β and TNF-α mRNA of lung tissue. Western blot was used to detect the expression levels of iNOS and COX-2 and the phosphorylation of p65 and IκBα in the NF-κB pathway in lung tissue. In vitro experiments were conducted with RAW267.4 cell inflammation model induced by 100 ng/ml LPS and A549 cell inflammation model induced by 10 μg/ml LPS. The effects of SA on M1-type and M2-type macrophages of RAW267.4 macrophages induced by LPS were detected by flow cytometry. The toxicity of compound SA to A549 cells was detected by MTT method which to determine the safe dose of SA. The expressions of COX-2 and the phosphorylation of p65 and IκBα protein in NF-κB pathway were detected by Western blot. ResultsWe found that the pre-treatment of SA significantly reduced the degree of lung injury, and the infiltration of neutrophils in the lung interstitium and alveolar space of the lung. The formation of transparent membrane in lung tissue and thickening of alveolar septum were significantly reduced compared with the model group, and the wet-dry ratio of the lung was also reduced. ELISA and RT-qPCR results showed that SA could significantly inhibit the production of IL-6, IL-1β, TNF-α. At the same time, SA could significantly inhibit the expression of iNOS and COX-2 proteins, and could inhibit the phosphorylation of p65 and IκBα proteins. in a dose-dependent manner. In vitro experiments, we found that flow cytometry showed that SA could significantly inhibit the polarization of macrophages from M0 type macrophages to M1-type macrophages, while SA could promote the polarization of M1-type macrophages to M2-type macrophages. The results of MTT assay showed that SA had no obvious cytotoxicity to A549 cells when the concentration was not higher than 80 μM, while LPS could promote the proliferation of A549 cells. In the study of anti-inflammatory effect, SA can significantly inhibit the expression of COX-2 and the phosphorylation of p65 and IκBα proteins in LPS-induced A549 cells. ConclusionSA has possessed a crucial anti-ALI role in LPS-induced mice. The mechanism was elucidated, suggesting that the inhibition of macrophage polarization to M1-type and the promotion of macrophage polarization to M2-type, as well as the inhibition of NF-κB pathway by SA may be the reasons for its anti-ALI. This finding provides important molecular evidence for the further application of SA in the clinical treatment of ALI.

α7nAChR Activation Combined with Endothelial Progenitor Cell Transplantation Attenuates Lung Injury in Diabetic Rats with Sepsis through the NF-κB Pathway.

Chronic diabetes mellitus compromises the vascular system, which causes organ injury, including in the lung. Due to the strong compensatory ability of the lung, patients always exhibit subclinical symptoms. Once sepsis occurs, the degree of lung injury is more severe under hyperglycemic conditions. The α7 nicotinic acetylcholine receptor (α7nAChR) plays an important role in regulating inflammation and metabolism and can improve endothelial progenitor cell (EPC) functions. In the present study, lung injury caused by sepsis was compared between diabetic rats and normal rats. We also examined whether α7nAChR activation combined with EPC transplantation could ameliorate lung injury in diabetic sepsis rats. A type 2 diabetic model was induced in rats via a high-fat diet and streptozotocin. Then, a rat model of septic lung injury was established by intraperitoneal injection combined with endotracheal instillation of LPS. The oxygenation indices, wet-to-dry ratios, and histopathological scores of the lungs were tested after PNU282987 treatment and EPC transplantation. IL-6, IL-8, TNF-α, and IL-10 levels were measured. Caspase-3, Bax, Bcl-2, and phosphorylated NF-κB (p-NF-κB) levels were determined by blotting. Sepsis causes obvious lung injury, which is exacerbated by diabetic conditions. α7nAChR activation and endothelial progenitor cell transplantation reduced lung injury in diabetic sepsis rats, alleviating inflammation and decreasing apoptosis. This treatment was more effective when PNU282987 and endothelial progenitor cells were administered together. p-NF-κB levels decreased following treatment with PNU282987 and EPCs. In conclusion, α7nAChR activation combined with EPC transplantation can alleviate lung injury in diabetic sepsis rats through the NF-κB signaling pathway.

Protective effect of apelin-13 on ventilator-induced acute lung injury.

Mechanical Ventilation (MV) is an essential mechanism of life support in the clinic. It may also lead to ventilator-induced acute lung injury (VILI) due to local alveolar overstretching and/or repeated alveolar collapse. However, the pathogenesis of VILI is not completely understood, and its occurrence and development may be related to physiological processes such as the inflammatory response, oxidative stress, and apoptosis. Some studies have found that the the apelin/APJ axis is an endogenous antagonistic mechanism activated during acute respiratory distress syndrome(ARDS), that can counteract the injury response and prevent uncontrolled lung injury. To indicate that apelin-13 plays a protective role in VILI, an animal model of VILI was established in this study to explore whether apelin-13 can alleviate VILI in rats by inhibiting inflammation, apoptosis and oxidative stress. SD rats were divided into four groups: control, high tidal volume, high tidal volume + normal saline and high tidal volume + apelin-13. After tracheotomy, the rats in control maintained spontaneous breathing, and the other rats were connected to the small animal ventilator for 4h to establish the rat VILI model. The mRNA expression of apelin was measured by real-time quantitative polymerase chain reaction(qRT-PCR), immunofluorescence and Western blotting(WB) were used to detect the expression level of APJ, and WB was used to detect the expression of the apoptotic proteins Bax and bcl-2. The degree of lung injury was evaluated by pathological staining of lung tissue,W/D ratio, and BALF total protein concentration. The expression of inflammatory factors(IL-1β, IL-6, TNF-α) in alveolar lavage fluid was measured using ELISA. The activities of MPO and cat and the content of MDA, an oxidative product, in lung tissue were measured to evaluate the degree of oxidative stress in the lung. After treatment with apelin-13, the apelin/APJ axis in the lung tissue of VILI model rats was activated, and the effect was further enhanced. The pathological damage of lung tissue was alleviated, the expression of the antiapoptotic protein Bcl-2 and the proapoptotic protein Bax was reversed, and the levels of the inflammatory cytokines IL-1β, IL-6, TNF-α levels were all decreased. MPO activity and MDA content decreased, while CAT activity increased. The apelin/apj axis is activated in VILI. Overexpression of apelin-13 further plays a protective role in VILI, mainly by including reducing pathological damage, the inflammatory response, apoptosis and antioxidant stress in lung tissue, thus delaying the occurrence and development of VILI.

Vitamin D3 improved hypoxia-induced lung injury by inhibiting the complement and coagulation cascade and autophagy pathway

BackgroundPulmonary metabolic dysfunction can cause lung tissue injury. There is still no ideal drug to protect against hypoxia-induced lung injury, therefore, the development of new drugs to prevent and treat hypoxia-induced lung injury is urgently needed. We aimed to explore the ameliorative effects and molecular mechanisms of vitamin D3 (VD3) on hypoxia-induced lung tissue injury.MethodsSprague–Dawley (SD) rats were randomly divided into three groups: normoxia, hypoxia, and hypoxia + VD3. The rat model of hypoxia was established by placing the rats in a hypobaric chamber. The degree of lung injury was determined using hematoxylin and eosin (H&E) staining, lung water content, and lung permeability index. Transcriptome data were subjected to differential gene expression and pathway analyses. In vitro, type II alveolar epithelial cells were co-cultured with hepatocytes and then exposed to hypoxic conditions for 24 h. For VD3 treatment, the cells were treated with low and high concentrations of VD3.ResultsTranscriptome and KEGG analyses revealed that VD3 affects the complement and coagulation cascade pathways in hypoxia-induced rats, and the genes enriched in this pathway were Fgb/Fga/LOC100910418. Hypoxia can cause increases in lung edema, inflammation, and lung permeability disruption, which are attenuated by VD3 treatment. VD3 weakened the complement and coagulation cascade in the lung and liver of hypoxia-induced rats, characterized by lower expression of fibrinogen alpha chain (Fga), fibrinogen beta chain (Fgb), protease-activated receptor 1 (PAR1), protease-activated receptor 3 (PAR3), protease-activated receptor 4 (PAR4), complement (C) 3, C3a, and C5. In addition, VD3 improved hypoxic-induced type II alveolar epithelial cell damage and inflammation by inhibiting the complement and coagulation cascades. Furthermore, VD3 inhibited hypoxia-induced autophagy in vivo and in vitro, which was abolished by the mitophagy inducer, carbonyl cyanide-m-chlorophenylhydrazone (CCCP).ConclusionVD3 alleviated hypoxia-induced pulmonary edema by inhibiting the complement and coagulation cascades and autophagy pathways.

QiShenYiQi pills preserve endothelial barrier integrity to mitigate sepsis-induced acute lung injury by inhibiting ferroptosis

Ethnopharmacological relevanceThe QiShengYiQi pill (QSYQ) is a traditional Chinese medicinal formulation. The effectiveness and safety of QSYQ in treating respiratory system disorders have been confirmed. Its pharmacological actions include anti-inflammation, antioxidative stress, and improving energy metabolism. However, the mechanism of QSYQ in treating sepsis-induced acute lung injury (si-ALI) remains unclear. Aim of the studySi-ALI presents a clinical challenge with high incidence and mortality rates. This study aims to confirm the efficacy of QSYQ in si-ALI and to explore the potential mechanisms, providing a scientific foundation for its application and insights for optimizing treatment strategies and identifying potential active components. Materials and methodsThe impact of QSYQ on si-ALI was evaluated using the cecal ligation and puncture (CLP) experimental sepsis animal model. The effects of QSYQ on endothelial cells were observed through coculturing with LPS-stimulated macrophage-conditioned medium. Inflammatory cytokine levels, HE staining, Evans blue staining, lung wet/dry ratio, and cell count and protein content in bronchoalveolar lavage fluid were used to assess the degree of lung injury. Network pharmacology was utilized to investigate the potential mechanisms of QSYQ in treating si-ALI. Western blot and immunofluorescence analyses were used to evaluate barrier integrity and validate mechanistically relevant proteins. ResultsQSYQ reduced the inflammation and alleviated pulmonary vascular barrier damage in CLP mice (all P < 0.05). A total of 127 potential targets through which QSYQ regulates si-ALI were identified, predominantly enriched in the RAGE pathway. The results of protein-protein interaction analysis suggest that COX2, a well-established critical marker of ferroptosis, is among the key targets. In vitro and in vivo studies demonstrated that QSYQ mitigated ferroptosis and vascular barrier damage in sepsis (all P < 0.05), accompanied by a reduction in oxidative stress and the inhibition of the COX2 and RAGE (all P < 0.05). ConclusionsThis study demonstrated that QSYQ maintains pulmonary vascular barrier integrity by inhibiting ferroptosis in CLP mice. These findings partially elucidate the mechanism of QSYQ in si-ALI and further clarify the active components of QSYQ, thereby providing a scientific theoretical basis for treating si-ALI with QSYQ.

A mass event of paraquat poisoning via inhalation.

In January 2023, a rare event of collective inhalation paraquat poisoning occurred in Shandong, China. To analyze the clinical characteristics of an event of respiratory tract paraquat poisoning through inhalation. Clinical data from eight patients with paraquat inhalation poisoning were retrospectively analyzed. The patients were mainly exposed to paraquat via the respiratory tract. The main clinical manifestations were ocular and respiratory irritation. Lung computed tomography (CT) showed that all eight patients had varying degrees of lung injury, mainly manifesting as exudative lesions. Laboratory tests revealed arterial blood gas hypoxemia, abnormal white blood cell count, and increased neutrophil ratio. Sufficient glucocorticoid impact therapy was effective, and all eight patients survived. Eight patients experienced chest tightness, shortness of breath, and varying degrees of lung injury due to inhalation of paraquat through the respiratory tract. The early use of glucocorticoids and other comprehensive treatment measures, active prevention and treatment of lung infections, and protection of organ function have beneficial effects in such cases.

Expression of Angiopoietin-2 in Lung Tissue of Juvenile SD Rats with Lipopolysaccharide-Induced Acute Lung Injury and the Role of Ulinastatin.

This study aimed to observe the expression of angiopoietin-2 (Ang-2) in the lung tissue of juvenile SD rats with lipopolysaccharide (LPS)-induced acute lung injury (ALI) and to clarify the role of ulinastatin (UTI). Ninety 18-21-day-old juvenile SD male rats were randomly divided into five groups (n = 18). ALI rat model was established by intraperitoneal injection of LPS (LPS 10mg/kg), while the control group was given the same dose of normal saline. The UTI intervention group was given the injection of UTI (5000 U/mL) immediately after the injection of LPS, which was divided into UTI low-dose group (LPS + 5ml/kg UTI), UTI medium-dose group (LPS + 10ml/kg UTI), and UTI high-dose group (LPS + 20ml/kg UTI).The respiratory status of each group of rats was observed, and six rats were randomly selected to be killed in each group at 6, 12, and 24h, and the lung tissues were dissected and retained. The pathological changes of the lung tissues were observed by hematoxylin-eosin (HE) staining, the expression levels and locations of Ang-2 and vascular endothelial growth factor (VEGF) in lung tissue were observed by immunohistochemical staining, and the expressions of genes and proteins of Ang-2 and VEGF were detected by quantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. Three hours after intraperitoneal injection, rats in the model group developed shortness of breath and the developed respiratory distress progressed over time. The lung pathological changes in the model group were obvious compared with those in the control group, and gradually worsened with time, and the pathological changes of lung in the rats in the UTI intervention group were reduced compared with those in the model group. At different time points, the expressions of Ang-2 and VEGF in the lung tissue of rats in the model group were higher than those in the control group, and were lower in the UTI intervention group than those in the model group. The expressions of Ang-2 and VEGF protein were lower in the low-dose group of UTI group than those in the high-dose group of UTI group at different time points (P < 0.05), and the expressions of Ang-2 and VEGF protein in the low-dose group of UTI were significantly lower than those in the medium-dose group at 12h and 24h (P < 0.05). The expression of Ang-2 was increased in the lung tissue of juvenile SD rats with LPS-induced ALI, and was associated with the degree of lung injury. UTI might attenuate LPS-induced ALI by inhibiting the expression of Ang-2 in lung tissue, and the low dose was more obvious than the medium and high dose.

The possibilities of computer tomography in the quantitative assessment of lung injury in SARS-COV-2 pneumonia

The aim of the study: to evaluate the effect of the degree of lung injury on the disease progression in COVID-19.Materials and methods: during the study, 100 patients were examined on the basis of the coronavirus hospital of the Non-commercial JSC «Karaganda medical university» (Karaganda city) among the ages from 18 to 93 years. All patients underwent computed tomography (CT) on Canon Aquilion Prime SP tomograph (160 sections). Scanning was carried out at admission, on 4-5, 8-9 days or according to indications. The degree of lung injury in CT was determined on the basis of an «empirical» percentage visual scale of CT 0-4. A comparative assessment of changes in lung tissue with the stages of the course of the disease SARS-COV-2 was carried out.Results and discussion: when comparing the indicators of the degree of lung damage in CT and the clinical severity of the disease, they have a weak direct correlation (P≥0.05).Conclusion: CT is a highly informative diagnostic method of SARS-COV-2 (sensitivity 97-98 %), allows to identify all semiotic elements of lung tissue injury, the extent of the pathological process, the effectiveness of the treatment and prediction of the clinical course of the disease.

What Remains up to 7 Months after Severe and Moderate Pneumonia in Non-Vaccinated Patients with Long COVID? Results of a CT Study.

There is a growing evidence of long-lasting lung changes after COVID-19. Our aim was to assess the degree of lung injury and evaluate the recovery process of 4-7-month-non-vaccinated convalescent patients discharged from hospital after moderate and severe COVID-19 pneumonia, who presented with symptoms of long-COVID. On control lung CT after mean 5-month recovery period, we classified and determined the prevalence of residual radiological abnormalities in 39 symptomatic patients. To assess the advancement of the persisting changes we used the total severity score (TSS) and the chest CT score and then correlated the results with clinical data. On follow-up CT images, 94.9% of patients showed persistent radiological abnormalities. The most frequent changes were ground-glass opacities (74.4%), reticular pattern (64.1%), fibrotic changes (53.8%), nodules (33.3%), bronchiectasis (15.4%), vascular enlargement (10.3%), and cavitation (5.1%). The median TSS score was 4.1 points (interquartile range 3), whereas the median of the chest CT score 5.4 points (interquartile range of 4.5). No significant differences were observed between sex subgroups and between the severe and moderate course groups. There were no association between both CT scores and the severity of the initial disease, indicating that, mean 5 months after the disease, pulmonary abnormalities reduced to a similar stage in both subgroups of severity.

Human placenta-derived mesenchymal stem cell administration protects against acute lung injury in a mouse model.

This study aims to investigate the effect of placenta-derived mesenchymal stem cells (PMSCs) administration on tissue repair following acute lung injury (ALI). PMSCs were transplanted intravenously to a mouse model of lipopolysaccharide-induced ALI. The therapeutic effects were determined by evaluating several indicators, including pathology; the wet/dry ratio of the lungs; blood gas analysis; the total protein content, cell numbers, and the activity of myeloperoxidase (MPO) in bronchial alveolar lavage fluid (BALF); and the levels of anti-inflammatory and proinflammatory cytokines in serum and BALF. To investigate the underlying mechanism, PMSC-derived exosomes were used for ALI treatment. Administration of PMSCs improved the degree of lung injury, reduced inflammation, increased the expression levels of anti-inflammatory cytokines, and protected lung function. As expected, the effects of PMSC-derived exosomes in the ALI model were similar to those of PMSCs, both in terms of improved lung function and reduced inflammation. These findings suggest that PMSCs have ameliorating effects on ALI that are potentially mediated via their secreted exosomes.

Tamibarotene targets heparin-binding protein for attenuating lung injury in sepsis.

Excessively active pulmonary inflammation is a hallmark of sepsis-induced lung damage. A synthetic retinoid drug called tamibarotene reduces inflammation in a variety of conditions, including acute promyelocytic leukemia (APL), renal fibrosis, and neuroinflammation. Its effect on sepsis-related lung injury, however, has not been explained. The purpose of the study was to investigate how tamibarotene affected lung damage induced by cecal ligation and puncture (CLP) procedure. A CLP sepsis mouse model was developed, and tamibarotene was pretreated to determine whether it improved lung injury and survival. The degree of lung injury was evaluated using the Hematoxylin and eosin staining and lung injury score. In order to determine pulmonary vascular permeability, measurements were taken for total protein and cell content of bronchoalveolar lavage fluid (BALF), wet/dry ratio of the lung, and Evans blue stain. The BALF inflammatory mediators, including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-1β, and IL-17A were discovered by enzyme-linked immunosorbent serologic assay (ELISA). Then, the levels of heparin-binding protein (HBP), and phospho-nuclear factor kappa-B (p-NF-κB) P65, and NF-κB P65 were determined using ELISA and Western blot analysis, respectively. Tamibarotene considerably increases survival and lessens lung damage stimulated by sepsis. Specifically, tamibarotene significantly relieves pulmonary vascular permeability and inhibits inflammation response in sepsis. Moreover, we further confirmed that these ameliorating effects of tamibarotene on sepsis may be exerted by targeting HBP and regulating the activation of NF-κB signaling pathway. These findings demonstrated that tamibarotene lessens sepsis-induced lung injury, and the effect could be exerted by targeting HBP and thereby deregulating the NF-κB signaling pathway.

A NETWORK PHARMACOLOGY-BASED TREATMENT ANALYSIS OF LUTEOLIN FOR REGULATING PYROPTOSIS IN ACUTE LUNG INJURY.

Background: Acute lung injury (ALI) and its severe manifestation, acute respiratory distress syndrome, are complicated pulmonary inflammatory conditions for which standard therapeutics are still not well established. Although increasing research has indicated the anti-inflammatory, anticancer, and antioxidant effects of luteolin, especially in lung diseases, the molecular mechanisms underlying luteolin treatment remain largely unclear. Methods: The potential targets of luteolin in ALI were explored using a network pharmacology-based strategy and further validated in a clinical database. The relevant targets of luteolin and ALI were first obtained, and the key target genes were analyzed using a protein-protein interaction network, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. The targets of luteolin and ALI were then combined to ascertain the relevant pyroptosis targets, followed by Gene Ontology analysis of core genes and molecular docking of key active compounds to the antipyroptosis targets of luteolin in resolving ALI. The expression of the obtained genes was verified using the Gene Expression Omnibus database. In vivo and in vitro experiments were performed to explore the potential therapeutic effects and mechanisms of action of luteolin against ALI. Results: Fifty key genes and 109 luteolin pathways for ALI treatment were identified through network pharmacology. Key target genes of luteolin for treating ALI via pyroptosis were identified. The most significant target genes of luteolin in ALI resolution included AKT1, NOS2, and CTSG. Compared with controls, patients with ALI had lower AKT1 expression and higher CTSG expression. Luteolin simply reduced systemic inflammation and lung tissue damage in septic mice. Furthermore, we blocked AKT1 expression and found luteolin reduced the degree of lung injury and affected NOS2 levels. Conclusions: As demonstrated by a network pharmacology approach, luteolin may exert an antipyroptosis effect on ALI via AKT1, NOS2, and CTSG.

The role of rhIGF-1/BP3 in the prevention of pulmonary hypertension in bronchopulmonary dysplasia and its underlying mechanism

BackgroundThis study aimed to determine whether postnatal treatment with recombinant human IGF-1 (rhIGF-1)/binding peptide 3 (BP3) ameliorates lung injury and prevents pulmonary hypertension (PH) in bronchopulmonary dysplasia (BPD) models.MethodsWe used two models of BPD in this study: one model that was associated with chorioamnionitis (CA), stimulated by intra-amniotic fluid and exposure to lipopolysaccharide (LPS), whereas the other was exposed to postnatal hyperoxia. Newborn rats were treated with rhIGF-1/BP3 (0.2 mg/Kg/d) or saline via intraperitoneal injection. The study endpoints included the wet/dry weight (W/D) ratio of lung tissues, radial alveolar counts (RACs), vessel density, right ventricular hypertrophy (RVH), lung resistance, and lung compliance. Hematoxylin and eosin (H&E) and Masson staining were used to evaluate the degree of lung injury and pulmonary fibrosis. IGF-1 and eNOS expression were detected using western blotting or quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). The levels of SP-C, E-cadherin, N-cadherin, FSP1, and Vimentin in the lung tissues were detected by immunofluorescence.ResultsLPS and hyperoxia treatment increased lung injury and pulmonary fibrosis, enhanced RVH and total respiratory resistance, and decreased RAC, pulmonary vascular density and pulmonary compliance in young mice (all p < 0.01). Simultaneously, LPS and hyperoxia induced an increase in epithelial-mesenchymal transition (EMT) in airway epithelial cells. However, rhIGF-1/BP3 treatment reduced lung injury and pulmonary fibrosis, decreased RVH and total respiratory resistance, and enhanced RAC, pulmonary vascular density and pulmonary compliance, as well as inhibited EMT in airway epithelial cells in LPS and hyperoxia treated mice.ConclusionPostnatal rhIGF-1/BP3 treatment relieved the effects of LPS or hyperoxia on lung injury and prevented RVH, providing a promising strategy for the treatment of BPD.

Single-cell transcriptomes reveal heterogeneity of chlorine-induced mice acute lung injury and the inhibitory effect of pentoxifylline on ferroptosis

To investigate the effect of pentoxifylline (PTX) on Chlorine (Cl2)-induced acute lung injury (ALI) by single-cell RNA sequencing (scRNA-seq). Female BALB/c mice were exposed to Cl2 at 400 ppm for 15 min. H&E staining was used to observe the degree of lung injury. scRNA-seq was conducted to analysis of normal and Cl2-exposed mice lung tissues. Immunofluorescence was used to observe genes of interest. Thirty-two mice were randomly divided into four groups: Control, Cl2, Cl2+Fer-1, Cl2+PTX. TEM, WB and ELISA were used to detect ferroptosis-related indicators. The 5, 8, 10, 12, 16, 20 clusters were epithelial cells and 4, 15, 18, 19, 21 clusters were endothelial cells. Pseudo-time analysis revealed the differentiation trajectory of epithelial cells and key regulatory genes (Gclc, Bpifa1, Dnah5 and Dnah9) during the process of injury. Cell–cell communication analysis identified several important receptor–ligand complexes (Nrp1-Vegfa, Nrp2-Vegfa, Flt1-Vegfa and Flt4-Vegfa). Ferroptosis were found up-regulated in epithelial and endothelial cells by GSVA analysis. Highly expressed genes to which closely related ferroptosis were found by SCENIC analysis. PTX could significantly decrease the levels of MDA and abnormal high expression of solute carrier family 7 member 11 (SLC7A11, the key transporter of cystine) as well as increase the expression of GSH/GSSG and glutathione peroxidase 4 (GPX4) (p < 0.05). This study revealed novel molecular features of Cl2-induced ALI. PTX may be a potential specific drug by inhibiting the process of ferroptosis in epithelial and endothelial cells.

Protective effect of anti-idiopathic pulmonary fibrosis drug Pirfenidone and Sufenidone (SC1011) on pulmonary injury induced by tuberculosis in a mouse tuberculosis model

Objective: To evaluate the protective effect of anti-idiopathic pulmonary fibrosis (IPF) marketed drug Pirfenidone and its clinical drug Sufenidone (SC1011) against lung injury in a mouse tuberculosis model. Methods: C57BL/6 mouse model of tuberculosis was established. A total of 75 C57BL/6 mice were infected with 1×107 CFU/ml H37Rv suspension by aerosol and randomly divided into untreated (n=9) group, isoniazid+rifampicin+pyrazinamide (HRZ) group (n=22), PFD+HRZ group (n=22), and SC1011+HRZ group (n=22). C57BL/6 mice were infected with H37Rv by aerosol for 6 weeks and then treated. Seven mice in each treatment group were weighed, sacrificed, dissected and observed for lung and spleen lesions at 4 and 8 weeks of treatment. HE staining and Masson staining were used to assess degree of lung injury and fibrosis, respectively. ELISA was used to assess the IFN-γ/TNF-α content in the serum of mice in each treatment group after 4 weeks of treatment. Hydroxyproline (HYP) content in lung tissue was measured by alkaline hydrolysis; meanwhile, CFU counts were used to assess the bacterial load in the lung and spleen of mice in each treatment group and the recurrence of spleen and lung tissue after 12 weeks of drug withdrawal. Results: At 8 weeks, the HYP content in the lung tissue was (630±58), (635±17), and (840±70) μg/mg in the PFD+HRZ, SC1011+HRZ, and HRZ treatment group, respectively (P<0.05).At 8 weeks, the proportion of Masson staining blue-stained area, that was, positive area, in lung tissue was 16.65%±1.82%, 10.01%±2.16%, and 21.36%±3.21%, respectively (F=27.11, P<0.001).The lung injury scores by HE staining at 8 weeks were (5.00±0.50), (5.00±0.47), and (6.89±0.99) points, respectively (F=19.81, P<0.001).The results of 4-week ELISA showed that the levels of TNF-α and IFN-γ in the serum of the SC1011+HRZ-treated group were lower than those of the HRZ-treated group (all P<0.05).The degree of lung injury and fibrosis in PFD+HRZ and SC1011+HRZ treatment groups were lower than those in HRZ treatment group (all P<0.001). The number of viable bacteria in the lung tissue of mice treated with PFD+HRZ, SC1011+HRZ, and HRZ for 4 weeks was lower than that of mice untreated [(1.82±0.10), (1.91±0.05), (1.79±0.17) vs. (5.27±0.07) lg(CFU+1)/ml, all P<0.05)]. And the aseptic transformation of the spleen of mice was achieved in each treatment group at 8 weeks of administration. After 12 weeks of drug withdrawal, the recurrence of lung infection in the SC1011+HRZ treatment group was 3/7 lower than 5/7 in the HRZ treatment group (P>0.05); the recurrence of spleen infection in the SC1011+HRZ treatment group was 1/7 lower than 5/7 in the HRZ treatment group (P>0.05).Pulmonary infection recurred more frequently in PFD+HRZ 6/7 versus HRZ 5/7 (P>0.05). Conclusions: PFD/SC1011, when combined with HRZ, reduced lung injury and reduced secondary fibrosis in pulmonary tuberculosis in C57BL/6 mice. SC1011 combined with HRZ has no significant short-term therapeutic effect on MTB, but may reduce its recurrence rate in long-term treatment, especially in reducing the recurrence rate of mouse spleen.

Protective role of FBXL19 in Streptococcus pneumoniae-induced lung injury in pneumonia immature mice

ObjectiveStreptococcus pneumoniae (Spn) is a common pathogen for pediatric pneumonia and leads to severe lung injury. This study is conducted to analyze the role of F-box and leucine rich repeat protein 19 (FBXL19) in Spn-induced lung injury in immature mice.MethodsImmature mice were infected with Spn to record the survival rates and bacterial loads in bronchoalveolar lavage fluid. Levels of FBXL19 and FOXM1 in lung tissues were determined via real-time quantitative polymerase chain reaction or Western blotting. After the interference of FBXL19, its impacts on lung inflammatory injury were appraised by the lung wet/dry weight ratio, myeloperoxidase activity, hematoxylin and eosin staining, and enzyme-linked immunosorbent assay. The binding of FBXL19 to forkhead box M1 (FOXM1) in mouse lung epithelial cells was determined. After MG132 treatment, the protein and ubiquitination levels of FOXM1 were measured. The functional rescue experiments were performed to analyze the role of FOXM1 in FBXL19-regulated lung injury.ResultsFBXL19 was downregulated while FOXM1 was upregulated in lung tissues of Spn-infected immature mice. Overexpression of FBXL19 reduced the degree of lung injury and inflammation. FBXL19 can bind to FOXM1 to reduce its protein level via ubiquitination degradation. MG132 reduced the ubiquitination and increased the protein level of FOXM1. Overexpression of FOXM1 reversed the protective role of FBXL19 overexpression in lung injury of Spn immature mice.ConclusionFBXL19 was downregulated by Spn and FBXL19 overexpression alleviated lung injury by inducing ubiquitination and degradation of FOXM1 in Spn immature mice.