A randomized control trial evaluating the advice of a physiological-model/digital twin-based decision support system on mechanical ventilation in patients with acute respiratory distress syndrome.

Background: Acute respiratory distress syndrome (ARDS) is highly heterogeneous, both in its clinical presentation and in the patient's physiological responses to changes in mechanical ventilator settings, such as PEEP. This study investigates the clinical efficacy of a physiological model-based ventilatory decision support system (DSS) to personalize ventilator therapy in ARDS patients.

Methods: This international, multicenter, randomized, open-label study enrolled patients with ARDS during the COVID-19 pandemic.

Ventilator-induced Lung Injury Promotes Inflammation within the Pleural Cavity.

Mechanical ventilation contributes to the morbidity and mortality of patients in intensive care, likely through the exacerbation and dissemination of inflammation. Despite the proximity of the pleural cavity to the lungs and exposure to physical forces, little attention has been paid to its potential as an inflammatory source during ventilation. Here, we investigate the pleural cavity as a novel site of inflammation during ventilator-induced lung injury.

Circulating Myeloid Cell-derived Extracellular Vesicles as Mediators of Indirect Acute Lung Injury.

Blood-borne myeloid cells, neutrophils and monocytes, play a central role in the development of indirect acute lung injury (ALI) during sepsis and noninfectious systemic inflammatory response syndrome. By contrast, the contribution of circulating myeloid cell-derived extracellular vesicles (EVs) to ALI is unknown, despite acute increases in their numbers during sepsis and systemic inflammatory response syndrome. Here, we investigated the direct role of circulating myeloid-EVs in ALI using a mouse isolated perfused lung system and a human cell coculture model of pulmonary vascular inflammation consisting of lung microvascular endothelial cells and peripheral blood mononuclear cells.

Correction of a chronic pulmonary disease through lentiviral vector-mediated protein expression.

We developed a novel lentiviral vector, pseudotyped with the F and HN proteins from Sendai virus (rSIV.F/HN), that produces long-lasting, high-efficiency transduction of the respiratory epithelium. Here we addressed whether this platform technology can secrete sufficient levels of a therapeutic protein into the lungs to ameliorate a fatal pulmonary disease as an example of its translational capability.

Microvesicle-Mediated Communication Within the Alveolar Space: Mechanisms of Uptake by Epithelial Cells and Alveolar Macrophages.

Intra-alveolar microvesicles (MVs) are important mediators of inter-cellular communication within the alveolar space, and are key components in the pathophysiology of lung inflammation such as acute respiratory distress syndrome (ARDS). Despite the abundance of data detailing the pro-inflammatory effects of MVs, it remains unclear how MVs interact or signal with target cells in the alveolus. Using both and alveolar models, we analyzed the dynamics of MV uptake by resident alveolar cells: alveolar macrophages and epithelial cells.

Investigation of Microvesicle Uptake by Mouse Lung-marginated Monocytes .

Extracellular microvesicles (MVs) are released into the circulation in large numbers during acute systemic inflammation, yet little is known of their intravascular cell/tissue-specific interactions under these conditions. We recently described a dramatic increase in the uptake of intravenously injected MVs by monocytes marginated within the pulmonary vasculature, in a mouse model of low-dose lipopolysaccharide-induced systemic inflammation. To investigate the mechanisms of enhanced MV uptake by monocytes, we developed an in vitro model using in vivo derived monocytes.

Update on the Features and Measurements of Experimental Acute Lung Injury in Animals: An Official American Thoracic Society Workshop Report.

Advancements in methods, technology, and our understanding of the pathobiology of lung injury have created the need to update the definition of experimental acute lung injury (ALI). We queried 50 participants with expertise in ALI and acute respiratory distress syndrome using a Delphi method composed of a series of electronic surveys and a virtual workshop. We propose that ALI presents as a "multidimensional entity" characterized by four "domains" that reflect the key pathophysiologic features and underlying biology of human acute respiratory distress syndrome.

Decision support system to evaluate ventilation in the acute respiratory distress syndrome (DeVENT study)-trial protocol.

Background: The acute respiratory distress syndrome (ARDS) occurs in response to a variety of insults, and mechanical ventilation is life-saving in this setting, but ventilator-induced lung injury can also contribute to the morbidity and mortality in the condition. The Beacon Caresystem is a model-based bedside decision support system using mathematical models tuned to the individual patient's physiology to advise on appropriate ventilator settings. Personalised approaches using individual patient description may be particularly advantageous in complex patients, including those who are difficult to mechanically ventilate and wean, in particular ARDS.

Secreted Extracellular Cyclophilin A Is a Novel Mediator of Ventilator-induced Lung Injury.

Mechanical ventilation is a mainstay of intensive care but contributes to the mortality of patients through ventilator-induced lung injury. eCypA (extracellular CypA [cyclophilin A]) is an emerging inflammatory mediator and metalloproteinase inducer, and the gene responsible for its expression has recently been linked to coronavirus disease (COVID-19). To explore the involvement of eCypA in the pathophysiology of ventilator-induced lung injury.

Intra-alveolar neutrophil-derived microvesicles are associated with disease severity in COPD.

Despite advances in the pathophysiology of chronic obstructive pulmonary disease (COPD), there is a distinct lack of biochemical markers to aid clinical management. Microvesicles (MVs) have been implicated in the pathophysiology of inflammatory diseases including COPD, but their association to COPD disease severity remains unknown. We analyzed different MV populations in plasma and bronchoalveolar lavage fluid (BALF) taken from 62 patients with mild to very severe COPD (51% male; mean age: 65.

Monocytes mediate homing of circulating microvesicles to the pulmonary vasculature during low-grade systemic inflammation.

Microvesicles (MVs), a plasma membrane-derived subclass of extracellular vesicles, are produced and released into the circulation during systemic inflammation, yet little is known of cell/tissue-specific uptake of MVs under these conditions. We hypothesized that monocytes contribute to uptake of circulating MVs and that their increased margination to the pulmonary circulation and functional priming during systemic inflammation produces substantive changes to the systemic MV homing profile. Cellular uptake of i.

Microvesicles as new therapeutic targets for the treatment of the acute respiratory distress syndrome (ARDS).

: Acute respiratory distress syndrome (ARDS) is a heterogeneous and multifactorial disease; it is a common and devastating condition that has a high mortality. Treatment is limited to supportive measures hence novel pharmacological approaches are necessary. We propose a new direction in ARDS research; this means moving away from thinking about individual inflammatory mediators and instead investigating how packaged information is transmitted between cells.

CCR2 mediates the adverse effects of LPS in the pregnant mouse.

In our earlier work, we found that intrauterine (i.u.) and intraperitoneal (i.

Ventilation following established ARDS: a preclinical model framework to improve predictive power.

Background: Despite advances in understanding the pathophysiology of acute respiratory distress syndrome, effective pharmacological interventions have proven elusive. We believe this is a consequence of existing preclinical models being designed primarily to explore biological pathways, rather than predict treatment effects. Here, we describe a mouse model in which both therapeutic intervention and ventilation were superimposed onto existing injury and explored the impact of β-agonist treatment, which is effective in simple models but not clinically.

Osteopontin mediates necroptosis in lung injury after transplantation of ischaemic renal allografts in rats.

Background: Respiratory complications after surgery are associated with morbidity and mortality. Acute lung injury can result from the systemic inflammatory response after acute kidney injury. The mechanisms behind this remote injury are not fully understood.

LPS-Induced Hypotension in Pregnancy: The Effect of Progesterone Supplementation.

Our previous work has shown that pregnancy exacerbates the hypotensive response to both infection and lipopolysaccharide (LPS). The high levels of progesterone (P4) associated with pregnancy have been suggested to be responsible for the pregnancy-induced changes in the cardiovascular response to infection. Here, we test the hypothesis that P4 supplementation exacerbates the hypotensive response of the maternal cardiovascular to LPS.

ATP redirects cytokine trafficking and promotes novel membrane TNF signaling microvesicles.

Cellular stress or injury induces release of endogenous danger signals such as ATP, which plays a central role in activating immune cells. ATP is essential for the release of nonclassically secreted cytokines such as IL-1β but, paradoxically, has been reported to inhibit the release of classically secreted cytokines such as TNF. Here, we reveal that ATP does switch off soluble TNF (17 kDa) release from LPS-treated macrophages, but rather than inhibiting the entire TNF secretion, ATP packages membrane TNF (26 kDa) within microvesicles (MVs).

Profiling inflammatory markers in patients with pneumonia on intensive care.

Clinical investigations lack predictive value when diagnosing pneumonia, especially when patients are ventilated and develop ventilator associated pneumonia (VAP). New tools to aid diagnosis are important to improve outcomes. This pilot study examines the potential for a panel of inflammatory mediators to aid in the diagnosis.

Progesterone, the maternal immune system and the onset of parturition in the mouse.

The role of progesterone (P4) in the regulation of the local (uterine) and systemic innate immune system, myometrial expression of connexin 43 (Cx-43) and cyclooxygenase 2 (COX-2), and the onset of parturition was examined in (i) naïve mice delivering at term; (ii) E16 mice treated with RU486 (P4-antagonist) to induce preterm parturition; and (iii) in mice treated with P4 to prevent term parturition. In naïve mice, myometrial neutrophil and monocyte numbers peaked at E18 and declined with the onset of parturition. In contrast, circulating monocytes did not change and although neutrophils were increased with pregnancy, they did not change across gestation.

The response of the innate immune and cardiovascular systems to LPS in pregnant and nonpregnant mice.

Sepsis is the leading cause of direct maternal mortality, but there are no data directly comparing the response to sepsis in pregnant and nonpregnant (NP) individuals. This study uses a mouse model of sepsis to test the hypothesis that the cardiovascular response to sepsis is more marked during pregnancy. Female CD1 mice had radiotelemetry probes implanted and were time mated.

High-Fat Feeding Protects Mice From Ventilator-Induced Lung Injury, Via Neutrophil-Independent Mechanisms.

Objective: Obesity has a complex impact on acute respiratory distress syndrome patients, being associated with increased likelihood of developing the syndrome but reduced likelihood of dying. We propose that such observations are potentially explained by a model in which obesity influences the iatrogenic injury that occurs subsequent to intensive care admission. This study therefore investigated whether fat feeding protected mice from ventilator-induced lung injury.

Intravascular donor monocytes play a central role in lung transplant ischaemia-reperfusion injury.

Rationale: Primary graft dysfunction in lung transplant recipients derives from the initial, largely leukocyte-dependent, ischaemia-reperfusion injury. Intravascular lung-marginated monocytes have been shown to play key roles in experimental acute lung injury, but their contribution to lung ischaemia-reperfusion injury post transplantation is unknown.

Objective: To define the role of donor intravascular monocytes in lung transplant-related acute lung injury and primary graft dysfunction.

Inhibition of TNF Receptor p55 By a Domain Antibody Attenuates the Initial Phase of Acid-Induced Lung Injury in Mice.

Background: Tumor necrosis factor-α (TNF) is strongly implicated in the development of acute respiratory distress syndrome (ARDS), but its potential as a therapeutic target has been hampered by its complex biology. TNF signals through two receptors, p55 and p75, which play differential roles in pulmonary edema formation during ARDS. We have recently shown that inhibition of p55 by a novel domain antibody (dAb™) attenuated ventilator-induced lung injury.