Pneumonectomy following penetrating trauma with ECMO as postoperative support: case report - (Lung trauma and ECMO).

BACKGROUND: Penetrating thoracic injuries have a significant risk of morbi-mortality. Despite the advancements in damage control methods, a subset of patients with severe pulmonary vascular lesions and bronchial injuries persists. In some of these cases, post-traumatic pneumonectomy is required, and perioperative extracorporeal membrane oxygenation (ECMO) support may be required due to right ventricular failure and respiratory failure. CASE DESCRIPTION: A male was brought to the emergency department (ED) with a penetrating thoracic injury, presenting with massive right hemothorax and active bleeding that required ligation of the right pulmonary hilum to control the bleeding. Subsequently, he developed right ventricular dysfunction and ARDS, necessitating a dynamic hybrid ECMO configuration to support his condition and facilitate recovery. CONCLUSIONS: Penetrating thoracic injuries with severe pulmonary vascular lesions may need pneumonectomy to control bleeding. ECMO support reduces the associated mortality by decreasing the complications rate. A multidisciplinary team is essential to achieve good outcomes in severe compromised patients.

Pulmonary Contusion-An Unusual Clinical and Radiological Presentation: Case Report.

Pulmonary contusion (PC), defined as damage to the lung parenchyma with edema and hemorrhage, has classically been associated with acceleration-deceleration injuries. It is a frequent pathology in clinical practice. However, its clinical presentation and imaging findings are nonspecific. Patients with this entity can present with findings that can range from mild dyspnea to life-threatening respiratory failure and hemodynamic instability. We present the case of a 61-year-old man, a former smoker, who presented to the emergency department after suffering blunt chest trauma. On admission, he complained of only mild shortness of breath, and his vital signs were typical. Initial imaging identified asymmetric pulmonary infiltrates and mediastinal lymphadenopathy; this was suspicious for additional pathology in addition to PC. After an exhaustive evaluation, a neoplastic or infectious disease process was ruled out. Even though the patient presented with a clinical deterioration of respiratory function compatible with secondary acute respiratory distress syndrome, there was a complete recovery after supportive measures and supplemental oxygen. In conclusion, the nonspecific clinical and imaging findings in patients with pulmonary contusion warrant a complete evaluation of these cases. An early diagnosis is essential to establish adequate support and monitoring to prevent possible complications that could worsen the patient's prognosis.

E-cigarette use-associated lung injury (EVALI).

The prevalence of vaping has overtaken conventional cigarettes as the most frequent form of nicotine consumption among 15-24-year olds. There are currently a large number of both legitimate and illegitimate products and suppliers offering more than 8000 different flavors of vape on the market, whose additives are not tested, studied or regulated and whose safety and toxicity profile remains unknown. In vitro studies have demonstrated a dose-dependent decrease in the viability of normal human bronchial epithelial cells after exposure to vapor from electronic vape devices.Short- and medium-term studies to date indicate that vapor-induced pulmonary lesions are the most serious and commonly reported side effect; such lesions include bilateral ground glass opacities in lung bases with subpleural preservation, bilateral infiltrates, pleural effusion, pneumomediastinum and nodular opacities. Cases of EVALI have been described in patients with daily exposure, as well as in users who reported having been exposed to these substances at least once a month. The most frequently inhaled substances are THC, flavored liquids of unknown content, and nicotine.The clinical manifestations of dyspnea and cough are the most frequent respiratory symptomatology, in addition to constitutional manifestations such as fever and chills, and gastrointestinal manifestations such as vomiting, nausea, abdominal pain and diarrhea. To these can be added the presence of tachypnea, tachycardia, elevated blood pressure, hypoxia, leukocytosis with neutrophilia and elevated ESR.

Modeling Mediated Crossover Acute and Subacute Damage to the Pulmonary System During Systemic (Subcutaneous) Administration of Bleomycin in Mice to Test the Potential Therapeutic Effect of Polyphenols / Modelado del Daño Agudo y Subagudo Cruzado Mediado al Sistema Pulmonar Durante la Infección Sistémica (Subcutánea) de Administración de Bleomicina a Ratones para Probar el Posible Efecto Terapéutico de los Polifenoles

SUMMARY: The potential anti-inflammatory and antifibrotic activity of polyphenolic extracts of blueberry and grape was evaluated in a mouse model of lung damage induced by subcutaneous administration of bleomycin. The results of testing the polyphenolic extracts on two different systemic administration variants of bleomycin (intraperitoneal and subcutaneous) were compared. It was found that regardless of the method of bleomycin administration, indirect cross-acute and subacute damage to the pulmonary system was observed. Both patterns exhibited the same prevalence and severity. The administration of polyphenolic extracts of blueberry and grape to mice resulted in a significant decrease in theseverity of acute and subacute patterns of lung damage, suggesting their protective properties for the microcirculatory bed and a pronounced anti-inflammatory effect.

La potencial actividad antiinflamatoria y antifibrótica de los extractos polifenólicos de arándano y uva se evaluó en un modelo de daño pulmonar en ratón inducido por la administración subcutánea de bleomicina. Se compararon los resultados de las pruebas de los extractos polifenólicos en dos variantes diferentes de administración sistémica de bleomicina (intraperitoneal y subcutánea). Se encontró que, independientemente del método de administración de bleomicina, se observaba daño indirecto cruzado, agudo y subagudo al sistema pulmonar. Ambos patrones exhibieron la misma prevalencia y gravedad. La administración de extractos polifenólicos de arándano y uva a ratones dio como resultado una disminución significativa en la gravedad de los patrones agudos y subagudos de daño pulmonar, lo que sugiere sus propiedades protectoras del lecho micro- circulatorio y un efecto antiinflamatorio pronunciado.

Anti-inflammatory and antioxidant properties of betaine protect against sepsis-induced acute lung injury: CT and histological evidence.

The aim of this research was to determine the anti-inflammatory effect of betaine on sepsis-induced acute respiratory distress syndrome (ARDS) in rats through histopathological examination, radiologic imaging, and biochemical analysis. Eight rats were included in the control group, and no procedure was performed. Feces intraperitoneal procedure (FIP) was performed on 24 rats to create a sepsis-induced ARDS model. These rats were separated into three groups as follows: FIP alone (sepsis group, n=8), FIP + saline (1 mL/kg, placebo group, n=8), and FIP + betaine (500 mg/kg, n=8). Computed tomography (CT) was performed after FIP, and the Hounsfield units (HU) value of the lungs was measured. The plasma levels of tumor necrosis factor (TNF)-α, interleukin-1ß (IL-1ß), IL-6, C-reactive protein, malondialdehyde (MDA), and lactic acid (LA) were determined, and arterial oxygen pressure (PaO2) and arterial CO2 pressure (PaCO2) were measured from an arterial blood sample. Histopathology was used to evaluate lung damage. This study completed all histopathological and biochemical evaluations in 3 months. All evaluated biomarkers were decreased in the FIP + betaine group compared to FIP + saline and FIP alone (all P<0.05). Also, the parenchymal density of the rat lung on CT and histopathological scores were increased in FIP + saline and FIP alone compared to control and these findings were reversed by betaine treatment (all P<0.05). Our study demonstrated that betaine suppressed the inflammation and ameliorated acute lung injury in a rat model of sepsis.

Assessing Pulmonary Epithelial Damage in Hantavirus Cardiopulmonary Syndrome: Challenging the Predominant Role of Vascular Endothelium through sRAGE as a Potential Biomarker.

Hantavirus cardiopulmonary syndrome (HCPS) is a severe respiratory illness primarily associated with microvascular endothelial changes, particularly in the lungs. However, the role of the pulmonary epithelium in HCPS pathogenesis remains unclear. This study explores the potential of soluble Receptors for Advanced Glycation End-products (sRAGE) as a biomarker for assessing pulmonary epithelial damage in severe HCPS, challenging the prevailing view that endothelial dysfunction is the sole driver of this syndrome. We conducted a cross-sectional study on critically ill HCPS patients, categorizing them into mild HCPS, severe HCPS, and negative control groups. Plasma sRAGE levels were measured, revealing significant differences between the severe HCPS group and controls. Our findings suggest that sRAGE holds promise as an indicator of pulmonary epithelial injury in HCPS and may aid in tracking disease progression and guiding therapeutic strategies. This study brings clarity on the importance of investigating the pulmonary epithelium's role in HCPS pathogenesis, offering potential avenues for enhanced diagnostic precision and support in this critical public health concern.

Changes in the levels of free sialic acid during ex vivo lung perfusion do not correlate with pulmonary function. Experimental model.

BACKGROUND: Ex vivo lung perfusion (EVLP) constitutes a tool with great research potential due to its advantages over in vivo and in vitro models. Despite its important contribution to lung reconditioning, this technique has the disadvantage of incurring high costs and can induce pulmonary endothelial injury through perfusion and ventilation. The pulmonary endothelium is made up of endothelial glycocalyx (EG), a coating of proteoglycans (PG) on the luminal surface. PGs are glycoproteins linked to terminal sialic acids (Sia) that can affect homeostasis with responses leading to edema formation. This study evaluated the effect of two ex vivo perfusion solutions on lung function and endothelial injury. METHODS: We divided ten landrace swine into two groups and subjected them to EVLP for 120 min: Group I (n = 5) was perfused with Steen® solution, and Group II (n = 5) was perfused with low-potassium dextran-albumin solution. Ventilatory mechanics, histology, gravimetry, and sialic acid concentrations were evaluated. RESULTS: Both groups showed changes in pulmonary vascular resistance and ventilatory mechanics (p < 0.05, Student's t-test). In addition, the lung injury severity score was better in Group I than in Group II (p < 0.05, Mann-Whitney U); and both groups exhibited a significant increase in Sia concentrations in the perfusate (p < 0.05 t-Student) and Sia immunohistochemical expression. CONCLUSIONS: Sia, as a product of EG disruption during EVLP, was found in all samples obtained in the system; however, the changes in its concentration showed no apparent correlation with lung function.

Evaluation of the therapeutic effects of oestradiol on the systemic inflammatory response and on lung injury caused by the occlusion of the proximal descending aorta in male rats.

OBJECTIVES: Ischaemia and reperfusion-induced microvascular dysfunction is a serious problem encountered during a variety surgical procedures, leading to systemic inflammation and affecting remote organs, specially the lungs. 17ß-Oestradiol reduces pulmonary repercussions from various acute lung injury forms. Here, we focused on the 17ß-oestradiol therapeutic effects after aortic ischaemia and reperfusion (I/R) by evaluating lung inflammation. METHODS: Twenty-four Wistar rats were submitted to I/R by insufflation of a 2-F catheter in thoracic aorta for 20 min. Reperfusion took 4 h and 17ß-oestradiol (280 µg/kg, i.v.) was administered after 1 h of reperfusion. Sham-operated rats were controls. Bronchoalveolar lavage was performed and lung samples were prepared for histopathological analysis and tissue culture (explant). Interleukin (IL)-1ß, IL-10 and tumour necrosis factor-α were quantified. RESULTS: After I/R, higher number of leukocytes in bronchoalveolar lavage were reduced by 17ß-oestradiol. The treatment also decreased leukocytes in lung tissue. I/R increased lung myeloperoxidase expression, with reduction by 17ß-oestradiol. Serum cytokine-induced neutrophil chemoattractant 1 and IL-1ß increased after I/R and 17ß-oestradiol decreased cytokine-induced neutrophil chemoattractant 1. I/R increased IL-1ß and IL-10 in lung explants, reduced by 17ß-oestradiol. CONCLUSIONS: Our results showed that 17ß-oestradiol treatment performed in the period of reperfusion, modulated the systemic response and the lung repercussions of I/R by thoracic aortic occlusion. Thus, we can suggest that 17ß-oestradiol might be a supplementary approach leading the lung deterioration after aortic clamping in surgical procedures.

A 43-Year-Old Brazilian Man with Acute Impairment of Lung Function and Pulmonary Nodules with Features of Electronic Cigarette or Vaping Product Use-Associated Lung Injury (EVALI).

BACKGROUND Electronic smoking devices were created, and their production industrialized, recently. Since their creation, their use has spread widely. This increase in users led to the appearance of a new lung condition. In 2019, the CDC established the criteria for the diagnosis of electronic cigarette or vaping product use-associated lung injury (EVALI) and the eponym EVALI is now widely recognized. The condition results from the inhalation of heated vapor, which damages the large and small airways and alveoli. CASE REPORT This report presents the case of a 43-year-old Brazilian man with acute impairment of lung function, pulmonary nodules on chest computed tomography (CT) and features of EVALI. He was hospitalized after 9 days of respiratory symptoms due to worsening dyspnea, and underwent a bronchoscopy on the same day. His condition evolved into severe hypercapnic respiratory failure that took 3 weeks to improve, and he underwent a surgical lung biopsy that showed an organizing pneumonia pattern. He was discharged after 50 days of hospitalization. Infectious diseases and other lung conditions were ruled out on clinical, laboratory, radiological, epidemiological, and histopathological grounds. CONCLUSIONS In conclusion, we report the unusual presentation of EVALI on chest CT showing nodules instead of a ground-glass pattern, as stated in the CDC definitions of a confirmed case. We also report the progression to a critical clinical state and, after treatment, the evolution to complete recovery. We also draw attention to the difficulties in diagnosing and managing the disease, especially at a time when COVID-19 has emerged.

Sulfasalazine prevents lung injury due to intra-abdominal sepsis in rats: possible role of Nrf2 and angiopoietin-2.

This study aimed to investigate the effect of sulfasalazine in preventing and treating intra-abdominal sepsis-induced acute respiratory distress syndrome (ARDS) in a rat model. Forty male Wistar albino rats were used. The rats were randomly divided into four equal groups, and sepsis was induced in 30 rats by intraperitoneal administration of a fecal saline solution prepared from rat feces. Group 1: normal control (n=10) [non-surgical], Group 2: fecal intraperitoneal injection (FIP) (n=10) [untreated septic group], Group 3: FIP+saline (placebo) (n=10) [saline administered intraperitoneally], Group 4 (n=10): FIP+sulfasalazine [250 mg/kg per day administered intraperitoneally]. Computed tomography was performed and blood samples were collected for biochemical and blood gas analysis. The lungs were removed for histopathological studies. Statistically significant reductions in interleukin (IL)-6, IL1-ß, tumor necrosis factor (TNF)-α, malondialdehyde (MDA), and angiopoietin-2 (ANG-2) levels were observed in the sulfasalazine group compared to the FIP+saline group (P<0.001). Nrf2 levels were significantly higher in the sulfasalazine-treated group than in the FIP and FIP+saline groups (P<0.01). Lung tissue scores were significantly reduced in the sulfasalazine group compared to the other sepsis groups. The Hounsfield unit (HU) value was significantly lower in the sulfasalazine group than in the FIP+saline group (P<0.001). PaO2 values were significantly higher in the sulfasalazine-treated group than in the FIP+saline-treated group (P<0.05). Sulfasalazine was shown to be effective in preventing and treating ARDS.

A Specific Pattern and Dynamics of Circulating Cytokines Are Associated with the Extension of Lung Injury and Mortality in Colombian Adults with Coronavirus Disease-19.

Increased systemic levels of inflammatory cytokines have been associated with the development of pathophysiologic events during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. To further explore differences in the pattern and dynamics of plasma cytokines in individuals with coronavirus disease-19 (COVID-19), and the relationship with disease mortality, here we evaluated the plasma levels of proinflammatory and regulatory cytokines in Colombian patient survivors and nonsurvivors of SARS-CoV-2 infection. Individuals with confirmed COVID-19, with other respiratory diseases requiring hospitalization, and healthy controls, were included. Plasma levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α, interferon-γ, IL-10, soluble tumor necrosis factor receptor I (sTNFRI), and transforming growth factor-ß1 were measured by a bead-based assay or enzyme-linked immunosorbent assay and clinical, laboratory, and tomographic parameters were registered during hospitalization. The levels of most of the evaluated cytokines were increased in COVID-19 individuals relative to healthy controls. The levels of IL-6, IL-10, and sTNFRI were directly associated with the development of respiratory failure, immune dysregulation, and coagulopathy, as well as with COVID-19 mortality. Particularly, the early, robust, and persistent increase of circulating IL-6 characterized COVID-19 nonsurvivors, while survivors were able to counteract the inflammatory cytokine response. In addition, IL-6 systemic levels positively correlated with the tomographic extension of lung damage in individuals with COVID-19. Thus, an exacerbated inflammatory cytokine response, particularly mediated by IL-6 added to the inefficiency of regulatory cytokines, distinguishes COVID-19-associated tissue disturbances, severity, and mortality in Colombian adults.

Exogenous surfactant reduces inflammation and redox imbalance in rats under prone or supine mechanical ventilation.

Mechanical ventilation (MV) is a lifesaving therapy for patients with acute or chronic respiratory failure. Despite, it can also cause lung injury by inducing or worsening inflammatory responses and oxidative stress. Several clinical approaches have protective effects on the lungs, including the prone position and exogenous surfactant; however, few studies have evaluated the association between the two strategies, especially in individuals without previous lung injury. We tested the hypothesis that the effects of the homogenization in lung aeration caused by the prone position in association with the anti-inflammatory properties of exogenous surfactant pre-treatment could have a cumulative protective effect against ventilator-induced lung injury. Therefore, Wistar rats were divided into four experimental groups: Mechanical Ventilation in Supine Position (MVSP), Mechanical Ventilation in Prone position (MVPP), Mechanical Ventilation in Supine Position + surfactant (MVSPS), and Mechanical Ventilation in Prone Position + Surfactant (MVPPS). The intranasal instillation of a porcine surfactant (Curosurf®) was performed in the animals of MVSPS and MVPPS 1 h before the MV, all the rats were subjected to MV for 1 h. The prone position in association with surfactant decreased mRNA expression levels of pro-inflammatory cytokines in ventilated animals compared to the supine position; in addition, the NfκB was lower in MVPP, MVSPS and MVPPS when compared to MVSP. However, it had no effects on oxidative stress caused by MV. Pre-treatment with exogenous surfactant was more efficient in promoting lung protection than the prone position, as it also reduced oxidative damage in the lung parenchyma. Nevertheless, the surfactant did not cause additional improvements in most parameters that were also improved by the prone position. Our results indicate that the pre-treatment with exogenous surfactant, regardless of the position adopted in mechanical ventilation, preserves the original lung histoarchitecture, reduces redox imbalance, and reduces acute inflammatory responses caused by mechanical ventilation in healthy adult Wistar rats.

Hérnia torácica traumática associada a laceração de lobo pulmonarcaudal em cão / Traumatic thoracic hernia associated with laceration of the caudal lung lobe in a dog

Traumas torácicos são comuns em pacientes traumatizados e incluem principalmente contusão pulmonar, laceração pulmonar, pneumotórax, hemotórax, fraturas de costela e esterno e hérnia diafragmática. As principais causas são acidentes automobilísticos, quedas e mordeduras. Taquipneia ou dispneia são possíveis sinais clínicos, associados a choque hipovolêmico e sinais gastrointestinais. Lesões torácicas podem ser negligenciadas quando lesões distrativas, como fratura de membros, estão presentes. Assim, o exame clínico minucioso é obrigatório e os animais com insuficiência respiratória podem necessitar de estabilização e cirurgia de emergência. Considerando a importância do trauma torácico na prática clínica, o objetivo deste manuscrito é relatar o caso de hérnia espúria torácica associada a laceração traumática de lobo pulmonar caudal em uma cadela apresentando dispneia intensa após trauma automobilístico. Após uma avaliação emergencial e exames radiográficos, foi diagnosticado tórax instável, fraturas de costelas, contusão pulmonar e pneumotórax grave. Após estabilização clínica, foi realizado tratamento cirúrgico para estabilização do tórax instável. Durante a cirurgia, observou-se herniação e laceração do lobo caudal esquerdo do pulmão, sendo realizadas suturas para correção da laceração pulmonar e estabilização do gradil costal, além da toracostomia para controle do pneumotórax. Nos casos de tórax instável e encarceramento lobar, o tratamento cirúrgico é fundamental, como realizado neste caso, com o objetivo de reparar e reposicionar o lobo pulmonar e estabilizar o tórax instável. A herniação pulmonar traumática é um possível diagnóstico diferencial no tórax instável pós-traumático, assim como a reparação do lobo e a estabilização das costelas por meio de suturas são técnicas eficazes de tratamento cirúrgico.

Thoracic traumas are common in trauma patients and mainly include pulmonary contusion, pulmonary laceration, pneumothorax, hemothorax, rib and sternum fractures and diaphragmatic hernia. The main causes are car accidents, falls and bites. Tachypnea or dyspnea are possible clinical signs, associated with hypovolemic shock and gastrointestinal signs. Thoracic injuries may be overlooked when distracting injuries, such as limb fractures, are present. Thus, thorough clinical examination is mandatory and animals with respiratory failure may require stabilization and emergency surgery. Considering the importance of thoracic trauma in clinical practice, the manuscript aimed to report the case of spurious thoracic hernia associated with traumatic laceration of the caudal lung lobe in a bitch with severe dyspnea after car trauma. After an emergency evaluation and radiographic examinations, a flail chest, rib fractures, pulmonary contusion and severe pneumothorax were diagnosed. After clinical stabilization, surgical treatment was performed to stabilize the flail chest. During surgery, herniation and laceration of the left caudal lobe of the lung were observed, and sutures were performed to correct the pulmonary laceration and stabilize the rib cage, in addition to thoracostomy to control the pneumothorax. In cases of flail chest and lobar entrapment, surgical treatment is essential, as in this case, with the aim of repairing and repositioning the pulmonary lobe and stabilizing the flail chest. Traumatic pulmonary herniation is a possible differential diagnosis in post-traumatic flail chest, as well as repairing the lobe and stabilizing the ribs using sutures are effective surgical treatment techniques.

The role of NMDA glutamate receptors in lung injury caused by chronic long-term intermittent hypobaric hypoxia.

Chronic intermittent hypoxia (CIH), a component of sleep apnea-hypopnea syndrome, is suggested to cause damage to lung tissue, and the role of glutamate is not well studied. We used a chronic long-term intermittent hypobaric hypoxia (CLTIHH) model of rats to find out if such procedure causes lung injury and the potential effect of N-methyl-D-aspartate receptors (NMDARs) by using receptor antagonist MK-801 (dizocilpine). Thirty-two rats were placed into four groups; a control and three CLTIHH groups where rats were placed into a low-pressure chamber set to 430 mmHg for 5 h/day, 5 days/week, for 5 weeks. Only one group received MK-801 (0.3 mg/kg, ip) daily. We evaluated tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, and nuclear factor (NF)-kB for the inflammatory process, superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT), glutathione peroxidase (GPX), total antioxidant status (TAS), and total oxidant status (TOS) for oxidative stress, and caspase-9 levels. Blood plasma, bronchoalveolar fluid (BALF), and lung tissue extracts were evaluated. Both oxidant and inflammatory parameters were significantly increased in all the mediums of the CLTIHH groups except the group that received MK-801. Significant evidence was collected on MK-801 alleviating the effect of CLTIHH. Histological evaluations revealed lung damage and fibrotic changes in the CLTIHH groups. It was first shown that the CLTIHH procedure caused chronic lung injury, and that inflammation and oxidant stress were influential in the formation of lung injury. Secondly, NMDAR antagonist MK-801 effectively inhibited the development of lung injury and fibrosis.

Lung Injury Is Induced by Abrupt Increase in Respiratory Rate but Prevented by Recruitment Maneuver in Mild Acute Respiratory Distress Syndrome in Rats.

BACKGROUND: Gradually changing respiratory rate (RR) during time to reduce ventilation-induced lung injury has not been investigated. The authors hypothesized that gradual, compared with abrupt, increments in RR would mitigate ventilation-induced lung injury and that recruitment maneuver before abruptly increasing RR may prevent injurious biologic impact. METHODS: Twenty-four hours after intratracheal administration of Escherichia coli lipopolysaccharide, 49 male Wistar rats were anesthetized and mechanically ventilated (tidal volume, 6 ml/kg; positive end-expiratory pressure, 3 cm H2O) with RR increase patterns as follows (n = 7 per group): (1) control 1, RR = 70 breaths/min for 2 h; (2) and (3) abrupt increases of RR for 1 and 2 h, respectively, both for 2 h; (4) shorter RR adaptation, gradually increasing RR (from 70 to 130 breaths/min during 30 min); (5) longer RR adaptation, more gradual increase in RR (from 70 to 130 breaths/min during 60 min), both for 2 h; (6) control 2, abrupt increase of RR maintained for 1 h; and (7) control 3, recruitment maneuver (continuous positive airway pressure, 30 cm H2O for 30 s) followed by control-2 protocol. RESULTS: At the end of 1 h of mechanical ventilation, cumulative diffuse alveolar damage scores were lower in shorter (11.0 [8.0 to 12.0]) and longer (13.0 [11.0 to 14.0]) RR adaptation groups than in animals with abrupt increase of RR for 1 h (25.0 [22.0 to 26.0], P = 0.035 and P = 0.048, respectively) and 2 h (35.0 [32.0 to 39.0], P = 0.003 and P = 0.040, respectively); mechanical power and lung heterogeneity were lower, and alveolar integrity was higher, in the longer RR adaptation group compared with abruptly adjusted groups; markers of lung inflammation (interleukin-6), epithelial (club cell secretory protein [CC-16]) and endothelial cell damage (vascular cell adhesion molecule 1 [VCAM-1]) were higher in both abrupt groups, but not in either RR adaptation group, compared with controls. Recruitment maneuver prevented the increase in VCAM-1 and CC-16 gene expressions in the abruptly increased RR groups. CONCLUSIONS: In mild experimental acute respiratory distress syndrome in rats, gradually increasing RR, compared with abruptly doing so, can mitigate the development of ventilation-induced lung injury. In addition, recruitment maneuver prevented the injurious biologic impact of abrupt increases in RR.

The Na/K-ATPase role as a signal transducer in lung inflammation.

Acute respiratory distress syndrome (ARDS) is marked by damage to the capillary endothelium and alveolar epithelium following edema formation and cell infiltration. Currently, there are no effective treatments for severe ARDS. Pathologies such as sepsis, pneumonia, fat embolism, and severe trauma may cause ARDS with respiratory failure. The primary mechanism of edema clearance is the epithelial cells' Na/K-ATPase (NKA) activity. NKA is an enzyme that maintains the electrochemical gradient and cell homeostasis by transporting Na+ and K+ ions across the cell membrane. Direct injury on alveolar cells or changes in ion transport caused by infections decreases the NKA activity, loosening tight junctions in epithelial cells and causing edema formation. In addition, NKA acts as a receptor triggering signal transduction in response to the binding of cardiac glycosides. The ouabain (a cardiac glycoside) and oleic acid induce lung injury by targeting NKA. Besides enzymatic inhibition, the NKA triggers intracellular signal transduction, fostering proinflammatory cytokines production and contributing to lung injury. Herein, we reviewed and discussed the crucial role of NKA in edema clearance, lung injury, and intracellular signaling pathway activation leading to lung inflammation, thus putting the NKA as a protagonist in lung injury pathology.

Glutamine ameliorates Bungarus multicinctus venom-induced lung and heart injury through HSP70: NF-κB p65 and P53/PUMA signaling pathways involved

Background: Bungarus multicinctus is one of the most dangerous venomous snakes prone to cardiopulmonary damage with extremely high mortality. In our previous work, we found that glutamine (Gln) and glutamine synthetase (GS) in pig serum were significantly reduced after Bungarus multicinctus bite. In the present study, to explore whether there is a link between the pathogenesis of cardiopulmonary injury and Gln metabolic changes induced by Bungarus multicinctus venom. We investigated the effect of Gln supplementation on the lung and heart function after snakebite. Methods: We supplemented different concentrations of Gln to mice that were envenomated by Bungarus multicinctus to observe the biological behavior, survival rate, hematological and pathological changes. Gln was supplemented immediately or one hour after the venom injection, and then changes in Gln metabolism were analyzed. Subsequently, to further explore the protective mechanism of glutamine on tissue damage, we measured the expression of heat-shock protein70 (HSP70), NF-κB P65, P53/PUMA by western blotting and real-time polymerase in the lung and heart. Results: Gln supplementation delayed the envenoming symptoms, reduced mortality, and alleviated the histopathological changes in the heart and lung of mice bitten by Bungarus multicinctus. Additionally, Gln increased the activity of glutamine synthetase (GS), glutamate dehydrogenase (GDH) and glutaminase (GLS) in serum. It also balanced the transporter SLC7A11 expression in heart and lung tissues. Bungarus multicinctus venom induced the NF-κB nuclear translocation in the lung, while the HO-1 expression was suppressed. At the same time, venom activated the P53/PUMA signaling pathway and the BAX expression in the heart. Gln treatment reversed the above phenomenon and increased HSP70 expression. Conclusion: Gln alleviated the glutamine metabolism disorder and cardiopulmonary damage caused by Bungarus multicinctus venom. It may protect lungs and heart against venom by promoting the expression of HSP70, inhibiting the activation of NF-κB and P53/PUMA, thereby delaying the process of snake venom and reducing mortality. The present results indicate that Gln could be a potential treatment for Bungarus multicinctus bite.

Pulmonary involvement from animal toxins: the cellular mechanisms

Venomous animals and their venom have always been of human interest because, despite species differences, coevolution has made them capable of targeting key physiological components of our bodies. Respiratory failure from lung injury is one of the serious consequences of envenomation, and the underlying mechanisms are rarely discussed. This review aims to demonstrate how toxins affect the pulmonary system through various biological pathways. Herein, we propose the common underlying cellular mechanisms of toxin-induced lung injury: interference with normal cell function and integrity, disruption of normal vascular function, and provocation of excessive inflammation. Viperid snakebites are the leading cause of envenomation-induced lung injury, followed by other terrestrial venomous animals such as scorpions, spiders, and centipedes. Marine species, particularly jellyfish, can also inflict such injury. Common pulmonary manifestations include pulmonary edema, pulmonary hemorrhage, and exudative infiltration. Severe envenomation can result in acute respiratory distress syndrome. Pulmonary involvement suggests severe envenomation, thus recognizing these mechanisms and manifestations can aid physicians in providing appropriate treatment.(AU)