Persistent elevation of inflammatory cytokines predicts a poor outcome in ARDS. Plasma IL-1 beta and IL-6 levels are consistent and efficient predictors of outcome over time

Proposal for the use of anakinra in acute respiratory distress secondary to COVID-19

The outcome of the SARS-CoV-2 (COVID-19) infection fundamentally affects the lung field, causing ACUTE RESPIRATORY DISTRESS SYNDROME (ARDS). This process is an inflammatory picture, involving an NLRP3 INFLAMOSOME-triggered cytokine storm, the main player in alveolar destruction. IL-1 beta stands out among the cytokines that are triggered in this picture. ANAKINRA is a potent biological drug, capable of blocking this IL 1 beta. We propose its use in controlling ARDS secondary to COVID-19 infection.

[Proposal for the use of anakinra in acute respiratory distress secondary to COVID-19]

The outcome of the SARS-CoV-2 (COVID-19) infection fundamentally affects the lung field, causing acute respiratory distress syndrome (ARDS). This process is an inflammatory picture, involving an NLRP3 inflamosome-triggered cytokine storm, the main player in alveolar destruction. IL-1 beta stands out among the cytokines that are triggered in this picture. Anakinra is a potent biological drug, capable of blocking this IL-1ß. We propose its use in controlling ARDS secondary to COVID-19 infection.

Interleukin-6 Inhibition Reduces Neuronal Injury In A Murine Model of Ventilator-Induced Lung Injury

Mechanical ventilation is a known risk factor for delirium, a cognitive impairment characterized by frontal cortex and hippocampal dysfunction. Although interleukin-6 (IL-6) is upregulated in mechanical ventilation-induced lung injury (VILI) and may contribute to delirium, it is not known whether inhibition of systemic IL-6 mitigates delirium-relevant neuropathology. To histologically define neuropathological effects of IL-6 inhibition in an experimental VILI model. VILI was simulated in anesthetized adult mice using a 35cc/kg tidal volume mechanical ventilation model. There were two controls groups: 1) spontaneously breathing, or 2) anesthetized and mechanically ventilated with 10cc/kg tidal volume to distinguish effects of anesthesia from VILI. Two hours prior to inducing VILI, mice were treated with either anti-IL-6 antibody, anti-IL-6 receptor antibody, or saline. Neuronal injury, stress, and inflammation were assessed using immunohistochemistry. Cleaved caspase-3 (CC3), a neuronal apoptosis marker, was significantly increased in the frontal (p<0.001) and hippocampal (p<0.0001) brain regions and accompanied by significant increases in c-Fos and heat shock protein-90 in the frontal cortices of VILI mice compared to controls (p<0.001). These findings were not related to cerebral hypoxia and there was no evidence of irreversible neuronal death. Frontal and hippocampal neuronal CC3 were significantly reduced with anti-IL-6 antibody (p<0.01 and p<0.0001, respectively), anti-IL-6 receptor antibody (p<0.05 and p<0.0001, respectively) compared to saline VILI mice. VILI induces potentially reversible neuronal injury and inflammation in the frontal cortex and hippocampus, which is mitigated with IL-6 inhibition. These data suggest a potentially novel neuroprotective role of systemic IL-6 inhibition that justifies further investigation.

Photobiomodulation and Antiviral Photodynamic Therapy in COVID-19 Management

Coronavirus disease 2019 (COVID-19) has shocked the world by its spread and contagiousness. There is no approved vaccine and no proven treatment for this infection. Some potential treatments that have already been associated with antiviral and anti-inflammatory effects are under investigation. Photobiomodulation therapy (PBMT) is a photon-based therapy that uses light to mediate a variety of metabolic, analgesic, anti-inflammatory, and immunomodulatory effects. Antiviral photodynamic therapy (aPDT) is a branch of photodynamic therapy based on the reaction between a photosensitizing agent and a light source in the presence of oxygen, which can produce oxidative and free radical agents to damage the viral structures such as proteins and nucleic acids. This chapter aims to discuss the potential therapeutic benefit of PBMT and aPDT in the context of the novel coronavirus. Studies indicate that PBMT and aPDT could be useful in many viral and bacterial pulmonary complications like influenza, SARS-CoV, and MERS, but we found no direct study on SARS-CoV-2. With a combination of PBMT and aPDT, we may be able to combat COVID-19 with minimal interference with pharmaceutical agents. It might improve the efficacy of PBMT and aPDT by using monoclonal antibodies and preparing new photosensitizers at the nanoscale that target the lung tissue specifically. More animal and human studies would need to take place to reach an effective protocol. This chapter would encourage other scientists to work on this new platform.

Identification of PBMC-based molecular signature associational with COVID-19 disease severity

The longevity of COVID-19 as a global pandemic, and the devastating effects it has had on certain subsets of individuals thus far has highlighted the importance of identifying blood-based biomarkers associated with disease severity. We employed computational and transcriptome analyses of publicly available datasets from PBMCs from 126 patients with COVID-19 admitted to ICU (n = 50), COVID-19 not admitted to ICU (n = 50), non-COVID-19 admitted to ICU (n = 16) and non-COVID-19 not admitted to ICU (n = 10), and utilized the Gencode V33 assembly to analyze protein coding mRNA and long noncoding RNA (lncRNA) transcriptomes in the context of disease severity. Our data identified several aberrantly expressed mRNA and lncRNA based biomarkers associated with SARS-CoV-2 severity, which in turn significantly affected canonical, upstream, and disease functions in each group of patients. Immune, interferon, and antiviral responses were severely suppressed in COVID-19 patients admitted to ICU versus those who were not admitted to ICU. Our data suggests a possible therapeutic approach for severe COVID-19 through administration of interferon therapy. Delving further into these biomarkers, roles and their implications on the onset and disease severity of COVID-19 could play a crucial role in patient stratification and identifying varied therapeutic options with diverse clinical implications.

Effect of ticagrelor on acute kidney injury in septic rats and its underlying mechanism

The aim of the present study was to determine whether the effects and underlying mechanisms of ticagrelor in a rat model of sepsis-induced acute kidney injury (AKI) were mediated via the CD62P pathway. A total of 15 rats were randomly assigned to the following groups: Normal, sham, cecal ligation and puncture (CLP), CLP + clinical dose of ticagrelor (CCD) and CLP + loading dose of ticagrelor (CLD). Ticagrelor was administered 12 h before modeling, immediately after modeling, and 12 h after modeling at a dose of 8.6 and 46.42 mg/kg in the CCD and CLD groups, respectively. Rats in the normal, sham and CLP groups were treated with the same volume of distilled water. Serum creatinine (SCr), CD62P and interleukin-1β (IL-1β) levels, myeloperoxidase (MPO) activity in the renal tissue and the apoptosis rate of renal cells were increased in the CLP group, compared with in the normal and sham groups (P<0.05). In addition, ticagrelor treatment reduced SCr, CD62P and IL-1β expression levels, renal tissue MPO activity and renal cell apoptosis in rats with sepsis-induced AKI (P<0.05). CD62P expression was closely associated with the occurrence of sepsis-induced AKI. The mechanism of ticagrelor-mediated reductions in inflammation, renal neutrophil infiltration and renal cell apoptosis is possibly associated with reductions in CD62P expression.

Endothelial cells and SARS-CoV-2: An intimate relationship

Angiotensin-converting enzyme 2 (ACE2) is an important player of the renin-angiotensin-aldosterone system (RAAS) in regulating the conversion of angiotensin II into angiotensin (1-7). While expressed on the surface of human cells, such as lung, heart, kidney, neurons, and endothelial cells (EC), ACE2 is the entry receptor for SARS-CoV-2. Here, we would like to highlight that ACE2 is predominant on the EC membrane. Many of coronavirus disease 2019 (COVID-19) symptoms have been associated with the large recruitment of immune cells, directly affecting EC. Additionally, cytokines, hypoxia, and complement activation can trigger the activation of EC leading to the coagulation cascade. The EC dysfunction plus the inflammation due to SARS-CoV-2 infection may lead to abnormal coagulation, actively participating in thrombo-inflammatory processes resulting in vasculopathy and indicating poor prognosis in patients with COVID-19. Considering the intrinsic relationship between EC and the pathophysiology of SARS-CoV-2, EC-associated therapies such as anticoagulants, fibrinolytic drugs, immunomodulators, and molecular therapies have been proposed. In this review, we will discuss the role of EC in the lung inflammation and edema, in the disseminate coagulation process, ACE2 positive cancer patients, and current and future EC-associated therapies to treat COVID-19.

Six-month Follow-up Chest CT Findings after Severe COVID-19 Pneumonia

Background Little is known about the long-term lung radiographic changes in patients who have recovered from coronavirus disease 2019 (COVID-19), especially those with severe disease. Purpose To prospectively assess pulmonary sequelae and explore the risk factors for fibrotic-like changes in the lung at 6-month follow-up chest CT of survivors of severe COVID-19 pneumonia. Materials and Methods A total of 114 patients (80 [70%] men; mean age, 54 years ± 12) were studied prospectively. Initial and follow-up CT scans were obtained a mean of 17 days ± 11 and 175 days ± 20, respectively, after symptom onset. Lung changes (opacification, consolidation, reticulation, and fibrotic-like changes) and CT extent scores (score per lobe, 0-5; maximum score, 25) were recorded. Participants were divided into two groups on the basis of their 6-month follow-up CT scan: those with CT evidence of fibrotic-like changes (traction bronchiectasis, parenchymal bands, and/or honeycombing) (group 1) and those without CT evidence of fibrotic-like changes (group 2). Between-group differences were assessed with the Fisher exact test, two-sample t test, or Mann-Whitney U test. Multiple logistic regression analyses were performed to identify the independent predictive factors of fibrotic-like changes. Results At follow-up CT, evidence of fibrotic-like changes was observed in 40 of the 114 participants (35%) (group 1), whereas the remaining 74 participants (65%) showed either complete radiologic resolution (43 of 114, 38%) or residual ground-glass opacification or interstitial thickening (31 of 114, 27%) (group 2). Multivariable analysis identified age of greater than 50 years (odds ratio [OR]: 8.5; 95% CI: 1.9, 38; P = .01), heart rate greater than 100 beats per minute at admission (OR: 5.6; 95% CI: 1.1, 29; P = .04), duration of hospital stay greater than or equal to 17 days (OR: 5.5; 95% CI: 1.5, 21; P = .01), acute respiratory distress syndrome (OR: 13; 95% CI: 3.3, 55; P < .001), noninvasive mechanical ventilation (OR: 6.3; 95% CI: 1.3, 30; P = .02), and total CT score of 18 or more (OR: 4.2; 95% CI: 1.2, 14; P = .02) at initial CT as independent predictors for fibrotic-like changes in the lung at 6 months. Conclusion Six-month follow-up CT showed fibrotic-like changes in the lung in more than one-third of patients who survived severe coronavirus disease 2019 pneumonia. These changes were associated with an older age, acute respiratory distress syndrome, longer hospital stays, tachycardia, noninvasive mechanical ventilation, and higher initial chest CT score. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Wells et al in this issue.

Evaluation of the gut microbiome in association with biological signatures of inflammation in murine polytrauma and shock

Severe injuries are frequently accompanied by hemorrhagic shock and harbor an increased risk for complications. Local or systemic inflammation after trauma/hemorrhage may lead to a leaky intestinal epithelial barrier and subsequent translocation of gut microbiota, potentially worsening outcomes. To evaluate the extent with which trauma affects the gut microbiota composition, we performed a post hoc analysis of a murine model of polytrauma and hemorrhage. Four hours after injury, organs and plasma samples were collected, and the diversity and composition of the cecal microbiome were evaluated using 16S rRNA gene sequencing. Although cecal microbial alpha diversity and microbial community composition were not found to be different between experimental groups, norepinephrine support in shock animals resulted in increased alpha diversity, as indicated by higher numbers of distinct microbial features. We observed that the concentrations of proinflammatory mediators in plasma and intestinal tissue were associated with measures of microbial alpha and beta diversity and the presence of specific microbial drivers of inflammation, suggesting that the composition of the gut microbiome at the time of trauma, or shortly after trauma exposure, may play an important role in determining physiological outcomes. In conclusion, we found associations between measures of gut microbial alpha and beta diversity and the severity of systemic and local gut inflammation. Furthermore, our data suggest that four hours following injury is too early for development of global changes in the alpha diversity or community composition of the intestinal microbiome. Future investigations with increased temporal-spatial resolution are needed in order to fully elucidate the effects of trauma and shock on the gut microbiome, biological signatures of inflammation, and proximal and distal outcomes.

Perspectives on Targeting IL-6 as a Potential Therapeutic Strategy for COVID-19

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has been a major threat to global public health. In Indonesia, the cases have rapidly increased, and the case fatality rate remains high. With COVID-19, most of the deaths have been caused by acute respiratory distress syndrome and dysregulation of the immune response. A lung biopsy from a patient with COVID-19 showed inflammatory cellular infiltration with diffuse alveolar damage. Massive pulmonary destruction has also been reported as a result of highly increased levels of proinflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-1β, interferon-γ (IFN-γ), induced protein 10 (IP-10), and monocyte chemoattractant protein-1 (MCP-1). IL-6 is an inflammatory cytokine produced by various cell types, including immune cells and nonleukocytes, such as endothelial cells, fibroblasts, epithelial cells, type II pneumocytes, and certain tumor cells. Several studies have shown that IL-6 contributes to the severity and mortality of COVID-19. In this review, we would like to explore the immune response in COVID-19 and the role of IL-6 in the immunopathogenesis of COVID-19.

IFN signaling and neutrophil degranulation transcriptional signatures are induced during SARS-CoV-2 infection

SARS-CoV-2 virus has infected more than 92 million people worldwide resulting in the Coronavirus disease 2019 (COVID-19). Using a rhesus macaque model of SARS-CoV-2 infection, we have characterized the transcriptional signatures induced in the lungs of juvenile and old macaques following infection. Genes associated with Interferon (IFN) signaling, neutrophil degranulation and innate immune pathways are significantly induced in macaque infected lungs, while pathways associated with collagen formation are downregulated, as also seen in lungs of macaques with tuberculosis. In COVID-19, increasing age is a significant risk factor for poor prognosis and increased mortality. Type I IFN and Notch signaling pathways are significantly upregulated in lungs of juvenile infected macaques when compared with old infected macaques. These results are corroborated with increased peripheral neutrophil counts and neutrophil lymphocyte ratio in older individuals with COVID-19 disease. Together, our transcriptomic studies have delineated disease pathways that improve our understanding of the immunopathogenesis of COVID-19.

Revised Korean Society of Infectious Diseases/National Evidence-based Healthcarea Collaborating Agency Guidelines on the Treatment of Patients with COVID-19

Despite the global effort to mitigate the spread, coronavirus disease 2019 (COVID-19) has become a pandemic that took more than 2 million lives. There are numerous ongoing clinical studies aiming to find treatment options and many are being published daily. Some effective treatment options, albeit of variable efficacy, have been discovered. Therefore, it is necessary to develop an evidence-based methodology, to continuously check for new evidence, and to update recommendations accordingly. Here we provide guidelines on pharmaceutical treatment for COVID-19 based on the latest evidence.

Flow cytometric evaluation of the neutrophil compartment in COVID-19 at hospital presentation: A normal response to an abnormal situation

Coronavirus disease 2019 (COVID-19) is a rapidly emerging pandemic disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Critical COVID-19 is thought to be associated with a hyper-inflammatory process that can develop into acute respiratory distress syndrome, a critical disease normally mediated by dysfunctional neutrophils. This study tested the hypothesis whether the neutrophil compartment displays characteristics of hyperinflammation in COVID-19 patients. Therefore, a prospective study was performed on all patients with suspected COVID-19 presenting at the emergency room of a large academic hospital. Blood drawn within 2 d after hospital presentation was analyzed by point-of-care automated flow cytometry and compared with blood samples collected at later time points. COVID-19 patients did not exhibit neutrophilia or eosinopenia. Unexpectedly neutrophil activation markers (CD11b, CD16, CD10, and CD62L) did not differ between COVID-19-positive patients and COVID-19-negative patients diagnosed with other bacterial/viral infections, or between COVID-19 severity groups. In all patients, a decrease was found in the neutrophil maturation markers indicating an inflammation-induced left shift of the neutrophil compartment. In COVID-19 this was associated with disease severity.

The deubiquitinase STAMBP modulates cytokine secretion through the NLRP3 inflammasome

The NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome is a multimeric, cytoplasmic, protein complex that regulates maturation and secretion of interleukin (IL)-1β, a potent pro-inflammatory cytokine. Critical to host defense against pathogens, IL-1β amplifies early innate immune responses by activating transcription of numerous other cytokines and chemokines. Excessive IL-1β is associated with poor outcomes in inflammatory illnesses, such as sepsis and the acute respiratory distress syndrome (ARDS). Tight regulation of this signaling axis is vital, but little is known about mechanisms to limit excessive inflammasome activity. Here we identify the deubiquitinase STAM-binding protein (STAMBP) as a negative regulator of the NLRP3 inflammasome. In monocytes, knockout of STAMBP by CRISPR/Cas9 gene editing increased expression of numerous cytokines and chemokines in response to Toll-like receptor (TLR) agonists or bacterial lipopolysaccharide (LPS). This exaggerated inflammatory response was dependent on IL-1β signaling, and STAMBP knockout directly increased release of IL-1β with TLR ligation. While STAMBP does not modulate NLRP3 protein abundance, cellular depletion of the deubiquitinase increased NLRP3 K63 chain polyubiquitination resulting in increased NLRP3 inflammasome activation. These findings describe a unique mechanism of non-degradative ubiquitination of NLRP3 by STAMBP to limit excessive inflammasome activation and to reduce injurious IL-1β signaling.

Local administration of p-coumaric acid decreases lipopolysaccharide-induced acute lung injury in mice: In vitro and in silico studies

Acute lung injury (ALI) remains to cause a high rate of mortality in critically ill patients. It is known that inflammation is a key factor in the pathogenesis of lipopolysaccharide (LPS)-induced ALI, which makes it a relevant approach to the treatment of ALI. In this study, we evaluated the potential of nasally instilled p-coumaric acid to prevent LPS-induced ALI in mice, by evaluating its effects on cellular and molecular targets involved in inflammatory response via in vitro and in silico approaches. Our results demonstrated that p-coumaric acid reduced both neutrophil accumulation and pro-inflammatory cytokine abundance, and simultaneously increased IL-10 production at the site of inflammation, potentially contributing to protection against LPS-induced ALI in mice. In the in vitro experiments, we observed inhibitory effects of p-coumaric acid against IL-6 and IL-8 production in stimulated A549 cells, as well as reactive oxygen species generation by neutrophils. In addition, p-coumaric acid treatment decreased neutrophil adhesion on the TNF-α-stimulated endothelial cells. According to the in silico predictions, p-coumaric acid reached stable interactions with both the ATP-binding site of IKKβ as well as the regions within LFA-1, critical for interaction with ICAM-1, thereby suppressing the production of proinflammatory mediators and hindering the neutrophil infiltration, respectively. Collectively, these findings indicate that p-coumaric acid is a promising anti-inflammatory agent that can be used for developing a pharmaceutical drug for the treatment of ALI and other inflammatory disorders.

BK Channels Regulate LPS-induced CCL-2 Release from Human Pulmonary Endothelial Cells

We recently established a role for the stretch-activated two-pore-domain K+ (K2P) channel TREK-1 (K2P2.1) in inflammatory cytokine secretion using models of hyperoxia-, mechanical stretch-, and TNF-α-induced acute lung injury. We have now discovered the expression of large conductance, Ca2+-activated K+ (BK) channels in human pulmonary microvascular endothelial cells and primary human alveolar epithelial cells using semiquantitative real-time PCR, IP and Western blot, and investigated their role in inflammatory cytokine secretion using an LPS-induced acute lung injury model. As expected, LPS induced IL-6 and CCL-2 secretion from pulmonary endothelial and epithelial cells. BK activation with NS1619 decreased LPS-induced CCL-2 but not IL-6 secretion from endothelial cells and had no effect on epithelial cells, although fluorometric assays revealed that BK activation hyperpolarized the plasma membrane potential (Em) of both cell types. Interestingly, BK inhibition (Paxilline) did not alter cytokine secretion or the Em in either cell type. Furthermore, LPS treatment by itself did not affect the Em or intracellular Ca2+ concentrations. Therefore, we propose BK channel activation as a novel targeted approach to counteract LPS-induced CCL-2 secretion from endothelial cells. This protective effect appears to occur via Em hyperpolarization but independent of intracellular Ca2+ concentrations.

Biological subphenotypes of acute respiratory distress syndrome may not reflect differences in alveolar inflammation

Biological subphenotypes have been identified in acute respiratory distress syndrome (ARDS) based on two parsimonious models: the "uninflamed" and "reactive" subphenotype (cluster-model) and "hypo-inflammatory" and "hyper-inflammatory" (latent class analysis (LCA) model). The distinction between the subphenotypes is mainly driven by inflammatory and coagulation markers in plasma. However, systemic inflammation is not specific for ARDS and it is unknown whether these subphenotypes also reflect differences in the alveolar compartment. Alveolar inflammation and dysbiosis of the lung microbiome have shown to be important mediators in the development of lung injury. This study aimed to determine whether the "reactive" or "hyper-inflammatory" biological subphenotype also had higher concentrations of inflammatory mediators and enrichment of gut-associated bacteria in the lung. Levels of alveolar inflammatory mediators myeloperoxidase (MPO), surfactant protein D (SPD), interleukin (IL)-1b, IL-6, IL-10, IL-8, interferon gamma (IFN-ƴ), and tumor necrosis factor-alpha (TNFα) were determined in the mini-BAL fluid. Key features of the lung microbiome were measured: bacterial burden (16S rRNA gene copies/ml), community diversity (Shannon Diversity Index), and community composition. No statistically significant differences between the "uninflamed" and "reactive" ARDS subphenotypes were found in a selected set of alveolar inflammatory mediators and key features of the lung microbiome. LCA-derived subphenotypes and stratification based on cause of ARDS (direct vs. indirect) showed similar profiles, suggesting that current subphenotypes may not reflect the alveolar host response. It is important for future research to elucidate the pulmonary biology within each subphenotype properly, which is arguably a target for intervention.

The potential involvement of P2X7 receptor in COVID-19 pathogenesis: A new therapeutic target?

Coronavirus disease 2019 (COVID-19) pathogenesis remains under investigation. Growing evidence indicates the establishment of a hyperinflammatory response, characterized by sustained production of cytokines, such as IL-1β. The release and maturation of this cytokine are dependent on the activation of a catalytic multiprotein complex, known as "inflammasome". The most investigated is the NLRP3 inflammasome, which can be activated by various stimuli, such as the recognition of extracellular ATP by the P2X7 receptor. Based on the recent literature, we present evidence that supports the idea that the P2X7R/NLRP3 axis may be involved in the immune dysregulation caused by the SARS-CoV-2 infection.

Clearance of inflammatory cytokines in patients with septic acute kidney injury during renal replacement therapy using the EMiC2 filter (Clic-AKI study)

BACKGROUND

The EMiC2 membrane is a medium cut-off haemofilter (45 kiloDalton). Little is known regarding its efficacy in eliminating medium-sized cytokines in sepsis. This study aimed to explore the effects of continuous veno-venous haemodialysis (CVVHD) using the EMiC2 filter on cytokine clearance.

METHODS

This was a prospective observational study conducted in critically ill patients with sepsis and acute kidney injury requiring kidney replacement therapy. We measured concentrations of 12 cytokines [Interleukin (IL) IL-1β, IL-1α, IL-2, IL-4, IL-6, IL-8, IL-10, interferon (IFN)-γ, tumour necrosis factor (TNF)-α, vascular endothelial growth factor, monocyte chemoattractant protein (MCP)-1, epidermal growth factor (EGF)] in plasma at baseline (T0) and pre- and post-dialyzer at 1, 6, 24, and 48 h after CVVHD initiation and in the effluent fluid at corresponding time points. Outcomes were the effluent and adsorptive clearance rates, mass balances, and changes in serial serum concentrations.

RESULTS

Twelve patients were included in the final analysis. All cytokines except EGF concentrations declined over 48 h (p < 0.001). The effluent clearance rates were variable and ranged from negligible values for IL-2, IFN-γ, IL-1α, IL-1β, and EGF, to 19.0 ml/min for TNF-α. Negative or minimal adsorption was observed. The effluent and adsorptive clearance rates remained steady over time. The percentage of cytokine removal was low for most cytokines throughout the 48-h period.

CONCLUSION

EMiC2-CVVHD achieved modest removal of most cytokines and demonstrated small to no adsorptive capacity despite a decline in plasma cytokine concentrations. This suggests that changes in plasma cytokine concentrations may not be solely influenced by extracorporeal removal.

TRIAL REGISTRATION

NCT03231748, registered on 27th July 2017.

A synthetic chalcone derivative, compound 39, alleviates lipopolysaccharide-induced acute lung injury in mice

Our research group has previously synthesized various chalcone analogues. Of these analogues, compound 39 has been shown to exhibit potent antioxidative activities but its anti-inflammatory and anti-apoptosis effects remain unclear. Thus, the present study investigated the in vivo and in vitro effects and mechanisms of compound 39 in lipopolysaccharide (LPS)-induced acute lung injury (ALI). To induce ALI, the mice received LPS via a tracheal instillation 6 h after intragastric administration of compound 39 or vehicle. Histological changes, the lung wet/dry weight ratio, and the amounts of protein and inflammatory cells in the broncho-alveolar lavage (BAL) fluid were assessed after 24 h. Additionally, to determine its underlying mechanisms, Western blot and immunofluorescence analyses were used. Moreover, the in vitro effects of compound 39 were also investigated. In the in vivo experiment, compound 39 markedly alleviated histopathological alterations, lung edema, and protein leakage, and exhibited potent anti-inflammatory effects. In the in vitro experiments, compound 39 dose-dependently reduced the levels of pro-inflammatory cytokines and reactive oxygen species. The results suggested that the anti-inflammatory effects of compound 39 were due to suppression of the mitogen-activated protein kinase (MAPK)/nuclear factor κB (NF-κB) pathway. Compound 39 also enhanced the protein levels of Bcl-2 and reduced the protein levels of Bax and cleaved caspase-3. The present study confirmed the anti-inflammatory, oxy-radical prohibitive, and anti-apoptosis activities of compound 39 against LPS-induced tissue and cell damage, and revealed the mechanisms underlying those processes.

Nanoparticle delivery of microRNA-146a regulates mechanotransduction in lung macrophages and mitigates injury during mechanical ventilation

Mechanical ventilation generates injurious forces that exacerbate lung injury. These forces disrupt lung barrier integrity, trigger proinflammatory mediator release, and differentially regulate genes and non-coding oligonucleotides including microRNAs. In this study, we identify miR-146a as a mechanosensitive microRNA in alveolar macrophages that has therapeutic potential to mitigate lung injury during mechanical ventilation. We use humanized in-vitro systems, mouse models, and biospecimens from patients to elucidate the expression dynamics of miR-146a needed to decrease lung injury during mechanical ventilation. We find that the endogenous increase in miR-146a following injurious ventilation is not sufficient to prevent lung injury. However, when miR-146a is highly overexpressed using a nanoparticle delivery platform it is sufficient to prevent injury. These data indicate that the endogenous increase in microRNA-146a during mechanical ventilation is a compensatory response that partially limits injury and that nanoparticle delivery of miR-146a is an effective strategy for mitigating lung injury during mechanical ventilation.

Central Administration of Angiotensin-(1-7) Improves Vasopressin Impairment and Hypotensive Response in Experimental Endotoxemia

Angiotensin-(1-7) [Ang-(1-7)]/Mas receptor is a counter-regulatory axis that counteracts detrimental renin-angiotensin system (RAS) effects, especially regarding systemic inflammation, vasopressin (AVP) release, and hypothalamic-pituitary-adrenal (HPA) activation. However, it is not completely understood whether this system may control centrally or systemically the late phase of systemic inflammation. Thus, the aim of this study was to determine whether intracerebroventricular (i.c.v.) administration of Ang-(1-7) can modulate systemic inflammation through the activation of humoral pathways in late phase of endotoxemia. Endotoxemia was induced by systemic injection of lipopolysaccharide (LPS) (1.5 mg/kg, i.v.) in Wistar rats. Ang-(1-7) (0.3 nmol in 2 µL) promoted the release of AVP and attenuated interleukin-6 (IL-6) and nitric oxide (NO) levels but increased interleukin-10 (IL-10) in the serum of the endotoxemic rats. The central administration of Mas receptor antagonist A779 (3 nmol in 2 µL, i.c.v.) abolished these anti-inflammatory effects in endotoxemic rats. Furthermore, Ang-(1-7) applied centrally restored mean arterial blood pressure (MABP) without affecting heart rate (HR) and prevented vascular hyporesponsiveness to norepinephrine (NE) and AVP in animals that received LPS. Together, our results indicate that Ang-(1-7) applied centrally promotes a systemic anti-inflammatory effect through the central Mas receptor and activation of the humoral pathway mediated by AVP.

SARS-CoV-2 leads to a small vessel endotheliitis in the heart

BACKGROUND

SARS-CoV-2 infection (COVID-19 disease) can induce systemic vascular involvement contributing to morbidity and mortality. SARS-CoV-2 targets epithelial and endothelial cells through the ACE2 receptor. The anatomical involvement of the coronary tree is not explored yet.

METHODS

Cardiac autopsy tissue of the entire coronary tree (main coronary arteries, epicardial arterioles/venules, epicardial capillaries) and epicardial nerves were analyzed in COVID-19 patients (n = 6). All anatomical regions were immunohistochemically tested for ACE2, TMPRSS2, CD147, CD45, CD3, CD4, CD8, CD68 and IL-6. COVID-19 negative patients with cardiovascular disease (n = 3) and influenza A (n = 6) served as controls.

FINDINGS

COVID-19 positive patients showed strong ACE2 / TMPRSS2 expression in capillaries and less in arterioles/venules. The main coronary arteries were virtually devoid of ACE2 receptor and had only mild intimal inflammation. Epicardial capillaries had a prominent lympho-monocytic endotheliitis, which was less pronounced in arterioles/venules. The lymphocytic-monocytic infiltrate strongly expressed CD4, CD45, CD68. Peri/epicardial nerves had strong ACE2 expression and lympho-monocytic inflammation. COVID-19 negative patients showed minimal vascular ACE2 expression and lacked endotheliitis or inflammatory reaction.

INTERPRETATION

ACE2 / TMPRSS2 expression and lymphomonocytic inflammation in COVID-19 disease increases crescentically towards the small vessels suggesting that COVID-19-induced endotheliitis is a small vessel vasculitis not involving the main coronaries. The inflammatory neuropathy of epicardial nerves in COVID-19 disease provides further evidence of an angio- and neurotrophic affinity of SARS-COV2 and might potentially contribute to the understanding of the high prevalence of cardiac complications such as myocardial injury and arrhythmias in COVID-19.

FUNDING

No external funding was necessary for this study.

Role of extracorporeal membrane oxygenation in critically Ill COVID-19 patients and predictors of mortality

The role of extracorporeal membrane oxygenation (ECMO) in the management of critically ill COVID‐19 patients remains unclear. Our study aims to analyze the outcomes and risk factors from patients treated with ECMO. This retrospective, single‐center study includes 17 COVID‐19 patients treated with ECMO. Univariate and multivariate parametric survival regression identified predictors of survival. Nine patients (53%) were successfully weaned from ECMO and discharged. The incidence of in‐hospital mortality was 47%. In a univariate analysis, only four out of 83 pre‐ECMO variables were significantly different; IL‐6, PCT, and NT‐proBNP were significantly higher in non‐survivors than in survivors. The Respiratory Extracorporeal Membrane Oxygenation Survival Prediction (RESP) score was significantly higher in survivors. After a multivariate parametric survival regression, IL‐6, NT‐proBNP and RESP scores remained significant independent predictors, with hazard ratios (HR) of 1.069 [95%‐CI: 0.986‐1.160], P = .016 1.001 [95%‐CI: 1.000‐1.001], P = .012; and .843 [95%‐CI: 0.564‐1.260], P = .040, respectively. A prediction model comprising IL‐6, NT‐proBNP, and RESP score showed an area under the curve (AUC) of 0.87, with a sensitivity of 87.5% and 77.8% specificity compared to an AUC of 0.79 for the RESP score alone. The present study suggests that ECMO is a potentially lifesaving treatment for selected critically ill COVID‐19 patients. Considering IL‐6 and NT‐pro‐BNP, in addition to the RESP score, may enhance outcome predictions.

COVID-19-associated acute respiratory distress syndrome (CARDS): Current knowledge on pathophysiology and ICU treatment - A narrative review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces coronavirus-19 disease (COVID-19) and is a major health concern. Following two SARS-CoV-2 pandemic “waves,” intensive care unit (ICU) specialists are treating a large number of COVID19-associated acute respiratory distress syndrome (ARDS) patients. From a pathophysiological perspective, prominent mechanisms of COVID19-associated ARDS (CARDS) include severe pulmonary infiltration/edema and inflammation leading to impaired alveolar homeostasis, alteration of pulmonary physiology resulting in pulmonary fibrosis, endothelial inflammation (endotheliitis), vascular thrombosis, and immune cell activation.

Although the syndrome ARDS serves as an umbrella term, distinct, i.e., CARDS-specific pathomechanisms and comorbidities can be noted (e.g., virus-induced endotheliitis associated with thromboembolism) and some aspects of CARDS can be considered ARDS “atypical.” Importantly, specific evidence-based medical interventions for CARDS (with the potential exception of corticosteroid use) are currently unavailable, limiting treatment efforts to mostly supportive ICU care.

In this article, we will discuss the underlying pulmonary pathophysiology and the clinical management of CARDS. In addition, we will outline current and potential future treatment approaches.

Prognostic value of lung ultrasound and its link with inflammatory biomarkers in patients with SARS-CoV-2 infection

Background

Lung ultrasound (LUS) has shown to correlate well with the findings obtained by chest computed tomography (CT) in acute-phase COVID-19. Although there is a significant correlation between blood biomarkers and CT radiological findings, a potential correlation between biochemical parameters and LUS images is still unknown. Our purpose was to evaluate whether mortality can be predicted from either of two lung ultrasound scoring systems (LUSS) as well as the potential association between lung lesions visualised by LUS and blood biomarkers.

Methods

We performed a retrospective observational study on 45 patients aged > 70 years with SARS-CoV-2 infection who required hospitalisation. LUS was carried out at admission and on day 7, when the clinical course was favourable or earlier in case of worsening. Disease severity was scored by means of LUSS in 8 (LUSS8) and in 12 (LUSS12) quadrants. LUS and blood draw for inflammatory marker analysis were performed at the same time.

Results

LUSS8 vs LUSS12 predicted mortality in 93.3% vs 91.1% of the cases; their associated odds ratios (OR) were 1.67 (95% CI 1.20–2.31) and 1.57 (95% CI 1.10–2.23), respectively. The association between biochemical parameters and LUSS scores was significant for ferritin; the OR for LUSS12 was 1.005 (95% CI 1.001–1.009) and for LUSS8 1.005 (95% CI 1.0–1.1), using thresholds for both of them.

Conclusions

The prognostic capacity of LUSS12 does not surpass that of LUSS8. There is a correlation between ferritin levels and LUSS.

K2P2.1 (TREK-1) potassium channel activation protects against hyperoxia-induced lung injury

No targeted therapies exist to counteract Hyperoxia (HO)-induced Acute Lung Injury (HALI). We previously found that HO downregulates alveolar K_2P2.1 (TREK-1) K⁺ channels, which results in worsening lung injury. This decrease in TREK-1 levels leaves a subset of channels amendable to pharmacological intervention. Therefore, we hypothesized that TREK-1 activation protects against HALI. We treated HO-exposed mice and primary alveolar epithelial cells (AECs) with the novel TREK-1 activators ML335 and BL1249, and quantified physiological, histological, and biochemical lung injury markers. We determined the effects of these drugs on epithelial TREK-1 currents, plasma membrane potential (Em), and intracellular Ca²⁺ (iCa) concentrations using fluorometric assays, and blocked voltage-gated Ca²⁺ channels (Ca_V) as a downstream mechanism of cytokine secretion. Once-daily, intra-tracheal injections of HO-exposed mice with ML335 or BL1249 improved lung compliance, histological lung injury scores, broncho-alveolar lavage protein levels and cell counts, and IL-6 and IP-10 concentrations. TREK-1 activation also decreased IL-6, IP-10, and CCL-2 secretion from primary AECs. Mechanistically, ML335 and BL1249 induced TREK-1 currents in AECs, counteracted HO-induced cell depolarization, and lowered iCa²⁺ concentrations. In addition, CCL-2 secretion was decreased after L-type Ca_V inhibition. Therefore, Em stabilization with TREK-1 activators may represent a novel approach to counteract HALI.

Endothelial Damage in Acute Respiratory Distress Syndrome

The pulmonary endothelium is a metabolically active continuous monolayer of squamous endothelial cells that internally lines blood vessels and mediates key processes involved in lung homoeostasis. Many of these processes are disrupted in acute respiratory distress syndrome (ARDS), which is marked among others by diffuse endothelial injury, intense activation of the coagulation system and increased capillary permeability. Most commonly occurring in the setting of sepsis, ARDS is a devastating illness, associated with increased morbidity and mortality and no effective pharmacological treatment. Endothelial cell damage has an important role in the pathogenesis of ARDS and several biomarkers of endothelial damage have been tested in determining prognosis. By further understanding the endothelial pathobiology, development of endothelial-specific therapeutics might arise. In this review, we will discuss the underlying pathology of endothelial dysfunction leading to ARDS and emerging therapies. Furthermore, we will present a brief overview demonstrating that endotheliopathy is an important feature of hospitalised patients with coronavirus disease-19 (COVID-19).

Small Resistance Artery Disease and ACE2 in Hypertension: A New Paradigm in the Context of COVID-19

Cardiovascular disease causes almost one third of deaths worldwide, and more than half are related to primary arterial hypertension (PAH). The occurrence of several deleterious events, such as hyperactivation of the renin–angiotensin system (RAS), and oxidative and inflammatory stress, contributes to the development of small vessel disease in PAH. Small resistance arteries are found at various points through the arterial tree, act as the major site of vascular resistance, and actively regulate local tissue perfusion. Experimental and clinical studies demonstrate that alterations in small resistance artery properties are important features of PAH pathophysiology. Diseased small vessels in PAH show decreased lumens, thicker walls, endothelial dysfunction, and oxidative stress and inflammation. These events may lead to altered blood flow supply to tissues and organs, and can increase the risk of thrombosis. Notably, PAH is prevalent among patients diagnosed with COVID-19, in whom evidence of small vessel disease leading to cardiovascular pathology is reported. The SARS-Cov2 virus, responsible for COVID-19, achieves cell entry through an S (spike) high-affinity protein binding to the catalytic domain of the angiotensin-converting enzyme 2 (ACE2), a negative regulator of the RAS pathway. Therefore, it is crucial to examine the relationship between small resistance artery disease, ACE2, and PAH, to understand COVID-19 morbidity and mortality. The scope of the present review is to briefly summarize available knowledge on the role of small resistance artery disease and ACE2 in PAH, and critically discuss their clinical relevance in the context of cardiovascular pathology associated to COVID-19.

Targeting Macrophages as a Therapeutic Option in Coronavirus Disease 2019

Immune cells of the monocyte/macrophage lineage are characterized by their diversity, plasticity, and variety of functions. Among them, macrophages play a central role in antiviral responses, tissue repair, and fibrosis. Macrophages can be reprogrammed by environmental cues, thus changing their phenotype during an antiviral immune response as the viral infection progresses. While M1-like macrophages are essential for the initial inflammatory responses, M2-like macrophages are critical for tissue repair after pathogen clearance. Numerous reports have evaluated the detrimental effects that coronaviruses, e.g., HCoV-229E, SARS-CoV, MERS-CoV, and SARS-CoV-2, have on the antiviral immune response and macrophage functions. In this review, we have addressed the breadth of macrophage phenotypes during the antiviral response and provided an overview of macrophage-coronavirus interactions. We also discussed therapeutic approaches to target macrophage-induced complications, currently under evaluation in clinical trials for coronavirus disease 2019 patients. Additionally, we have proposed alternative approaches that target macrophage recruitment, interferon signaling, cytokine storm, pulmonary fibrosis, and hypercoagulability.

Importance of Deubiquitination in Macrophage-Mediated Viral Response and Inflammation

Ubiquitination and deubiquitination play a fundamental role in the signaling pathways associated with innate and adaptive immune responses. Macrophages are key sentinels for the host defense, triggering antiviral and inflammatory responses against various invading pathogens. Macrophages recognize the genetic material of these pathogens as pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) through the activation of its pattern recognition receptors (PRRs), initiating the cascade of immune signaling, which leads to the production of pro- and anti-inflammatory cytokines that initiates the appropriate immune response. Macrophage-mediated immune response is highly regulated and tightly controlled by the ubiquitin system since its abnormal activation or dysregulation may result in the severe pathogenesis of numerous inflammatory and autoimmune diseases. Deubiquitinating enzymes (DUBs) play a crucial role in reversing the ubiquitination and controlling the magnitude of the immune response. During infection, pathogens manipulate the host defense system by regulating DUBs to obtain nutrients and increase proliferation. Indeed, the regulation of DUBs by small molecule inhibitors has been proposed as an excellent way to control aberrant activation of immune signaling molecules. This review is focused on the complex role of DUBs in macrophage-mediated immune response, exploring the potential use of DUBs as therapeutic targets in autoimmune and inflammatory diseases by virtue of small molecule DUB inhibitors.

Investigation of anti-inflammatory effects of oxygen nanobubbles in a rat hydrochloric acid lung injury model

Aim: To investigate the anti-inflammatory effect of oxygen nanobubbles (ONBs) in an acute lung injury rat model. Materials & methods: In a rat hydrochloric acid lung injury model, ONB fluid was administered intravenously in the ONB group (n = 6) and normal saline was administered in the control group (n = 6). 4 h later, arterial partial pressure of oxygen (PaO₂), mean arterial pressure and plasma inflammatory cytokines were measured. Results: There were no significant differences in the PaO₂, mean arterial pressure or TNF-α and IL-6 levels between the two groups. Conclusions: No anti-inflammatory effect could be confirmed at the present ONB dose in the rat model of acute lung injury.

Title: Cytokine release syndrome is not usually caused by secondary hemophagocytic lymphohistiocytosis in a cohort of 19 critically ill COVID-19 patients

Severe COVID-19 associated respiratory failure, poses the one challenge of our days. Assessment and treatment of COVID-19 associated hyperinflammation may be key to improve outcomes. It was speculated that in subgroups of patients secondary hemophagocytic lymphohistiocytosis (sHLH) or cytokine release syndrome (CRS) with features of macrophage activation syndrome might drive severe disease trajectories. If confirmed, profound immunosuppressive therapy would be a rationale treatment approach. Over a median observation period of 11 (IQR: 8; 16) days, 19 consecutive confirmed severe COVID-19-patients admitted to our intensive-care-unit were tested for presence of sHLH by two independent experts. HScores and 2004-HLH diagnostic criteria were assessed. Patients were grouped according to short-term clinical courses: discharge from ICU versus ongoing ARDS or death at time of analysis. The median HScore at admission was 157 (IQR: 98;180), without the key clinical triad of HLH, i.e. progressive cytopenia, persistent fever and organomegaly. Independent expert chart review revealed the absence of sHLH in all cases. No patient reached more than 3/6 of modified HLH 2004 criteria. Nevertheless, patients presented hyperinflammation with peripheral neutrophilic signatures (neutrophil/lymphocyte-ratio > 3.5). The latter best paralleled their short-term clinical courses, with declining relative neutrophil numbers prior to extubation (4.4, [IQR: 2.5;6.3]; n = 8) versus those with unfavourable courses (7.6, [IQR: 5.2;31], n = 9). Our study rules out virus induced sHLH as the leading cause of most severe-COVID-19 trajectories. Instead, an associated innate neutrophilic hyperinflammatory response or virus-associated-CRS appears dominant in patients with an unfavourable clinical course. Therapeutic implications are discussed.

Probable positive effects of the photobiomodulation as an adjunctive treatment in COVID-19: A systematic review

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Photobiomodulation (PBM) can reduce lung edema, cytokines in bronchoalveolar parenchyma, neutrophil influx.

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PBM reduces TNF-α, IL-1β, IL-6, ICAM-1, MIP-2 and Reactive oxygen species.

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Transthoracic approach is the direct methods for reducing lung inflammation.

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Intravenous approach increases the oxygenation of red blood cells.

Background

COVID-19, as a newly-emerged viral infection has now spread all over the world after originating in Wuhan, China. Pneumonia is the hallmark of the disease, with dyspnea in half of the patients and acute respiratory distress syndrome (ARDS) in up to one –third of the cases. Pulmonary edema, neutrophilic infiltration, and inflammatory cytokine release are the pathologic signs of this disease. The anti-inflammatory effect of the photobiomodulation (PBM) has been confirmed in many previous studies. Therefore, this review study was conducted to evaluate the direct effect of PBM on the acute lung inflammation or ARDS and also accelerating the regeneration of the damaged tissues. The indirect effects of PBM on modulation of the immune system, increasing the blood flow and oxygenation in other tissues were also considered.

Methodology

The databases of PubMed, Cochrane library, and Google Scholar were searched to find the relevant studies. Keywords included the PBM and related terms, lung inflammation, and COVID-19 -related signs. Studies were categorized with respect to the target tissue, laser parameters, and their results.

Results

Seventeen related papers were included in this review. All of them were in animal models. They showed that the PBM could significantly decrease the pulmonary edema, neutrophil influx, and generation of pro-inflammatory cytokines (tumor necrosis factor-α (TNF-α), interleukin 1 beta (IL-1β), interleukin 6 (IL-6), intracellular adhesion molecule (ICAM), reactive oxygen species (ROS), isoform of nitric oxide synthase (iNOS), and macrophage inflammatory protein 2 (MIP-2)).

Conclusion

Our findings revealed that the PBM could be helpful in reducing the lung inflammation and promoting the regeneration of the damaged tissue. PBM can increase the oxygenation indirectly in order to rehabilitate the affected organs. Thus, the infra-red lasers or light-emitting diodes (LEDs) are recommended in this regard.

The Inflammasome in Times of COVID-19

Coronaviruses (CoVs) are members of the genus Betacoronavirus and the Coronaviridiae family responsible for infections such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and more recently, coronavirus disease-2019 (COVID-19). CoV infections present mainly as respiratory infections that lead to acute respiratory distress syndrome (ARDS). However, CoVs, such as COVID-19, also present as a hyperactivation of the inflammatory response that results in increased production of inflammatory cytokines such as interleukin (IL)-1β and its downstream molecule IL-6. The inflammasome is a multiprotein complex involved in the activation of caspase-1 that leads to the activation of IL-1β in a variety of diseases and infections such as CoV infection and in different tissues such as lungs, brain, intestines and kidneys, all of which have been shown to be affected in COVID-19 patients. Here we review the literature regarding the mechanism of inflammasome activation by CoV infection, the role of the inflammasome in ARDS, ventilator-induced lung injury (VILI), and Disseminated Intravascular Coagulation (DIC) as well as the potential mechanism by which the inflammasome may contribute to the damaging effects of inflammation in the cardiac, renal, digestive, and nervous systems in COVID-19 patients.

Tert-butylhydroquinone augments Nrf2-dependent resilience against oxidative stress and improves survival of ventilator-induced lung injury in mice

Oxidative stress caused by mechanical ventilation contributes to the pathophysiology of ventilator-induced lung injury (VILI). A key mechanism maintaining redox balance is the upregulation of nuclear factor-erythroid-2-related factor 2 (Nrf2)-dependent antioxidant gene expression. We tested whether pretreatment with an Nrf2-antioxidant response element (ARE) pathway activator tert-butylhydroquinone (tBHQ) protects against VILI. Male C57BL/6J mice were pretreated with an intraperitoneal injection of tBHQ (n = 10), an equivalent volume of 3% ethanol (EtOH3%, vehicle, n = 13), or phosphate-buffered saline (controls, n = 10) and were then subjected to high tidal volume (HV_T) ventilation for a maximum of 4 h. HV_T ventilation severely impaired arterial oxygenation ([Formula: see text] = 49 ± 7 mmHg, means ± SD) and respiratory system compliance, resulting in a 100% mortality among controls. Compared with controls, tBHQ improved arterial oxygenation ([Formula: see text] = 90 ± 41 mmHg) and respiratory system compliance after HV_T ventilation. In addition, tBHQ attenuated the HV_T ventilation-induced development of lung edema and proinflammatory response, evidenced by lower concentrations of protein and proinflammatory cytokines (IL-1β and TNF-α) in the bronchoalveolar lavage fluid, respectively. Moreover, tBHQ enhanced the pulmonary redox capacity, indicated by enhanced Nrf2-depentent gene expression at baseline and by the highest total glutathione concentration after HV_T ventilation among all groups. Overall, tBHQ pretreatment resulted in 60% survival (P < 0.001 vs. controls). Interestingly, compared with controls, EtOH3% reduced the proinflammatory response to HV_T ventilation in the lung, resulting in 38.5% survival (P = 0.0054 vs. controls). In this murine model of VILI, tBHQ increases the pulmonary redox capacity by activating the Nrf2-ARE pathway and protects against VILI. These findings support the efficacy of pharmacological Nrf2-ARE pathway activation to increase resilience against oxidative stress during injurious mechanical ventilation.

ACE2: Its potential role and regulation in severe acute respiratory syndrome and COVID-19

COVID-19, a new disease caused by the 2019-novel coronavirus (SARS-CoV-2), has swept the world and challenged its culture, economy, and health infrastructure. Forced emergence to find an effective vaccine to immunize people has led scientists to design and examine vaccine candidates all over the world. Until a vaccine is developed, however, effective treatment is needed to combat this virus, which is resistant to all conventional antiviral drugs. Accordingly, more about the structure, entry mechanism, and pathogenesis of COVID-19 is required. Angiotensin-converting enzyme 2 (ACE2) is the gateway to SARS-CoV and SARS-CoV-2, so our knowledge of SARS-CoV-2 can help us to complete its mechanism of interaction with ACE2 and virus endocytosis, which can be interrupted by neutralizing small molecules or proteins. ACE2 also plays a crucial role in lung injury.

Cytokine profile in plasma of severe COVID-19 does not differ from ARDS and sepsis

BACKGROUND

Elevated levels of inflammatory cytokines have been associated with poor outcomes among COVID-19 patients. It is unknown, however, how these levels compare with those observed in critically ill patients with acute respiratory distress syndrome (ARDS) or sepsis due to other causes.

METHODS

We used a Luminex assay to determine expression of 76 cytokines from plasma of hospitalized COVID-19 patients and banked plasma samples from ARDS and sepsis patients. Our analysis focused on detecting statistical differences in levels of 6 cytokines associated with cytokine storm (IL-1β, IL-1RA, IL-6, IL-8, IL-18, and TNF-α) between patients with moderate COVID-19, severe COVID-19, and ARDS or sepsis.

RESULTS

Fifteen hospitalized COVID-19 patients, 9 of whom were critically ill, were compared with critically ill patients with ARDS (n = 12) or sepsis (n = 16). There were no statistically significant differences in baseline levels of IL-1β, IL-1RA, IL-6, IL-8, IL-18, and TNF-α between patients with COVID-19 and critically ill controls with ARDS or sepsis.

CONCLUSION

Levels of inflammatory cytokines were not higher in severe COVID-19 patients than in moderate COVID-19 or critically ill patients with ARDS or sepsis in this small cohort. Broad use of immunosuppressive therapies in ARDS has failed in numerous Phase 3 studies; use of these therapies in unselected patients with COVID-19 may be unwarranted.

FUNDING

Funding was received from NHLBI K23 HL125663 (AJR); The Bill and Melinda Gates Foundation OPP1113682 (AJR and CAB); Burroughs Wellcome Fund Investigators in the Pathogenesis of Infectious Diseases #1016687 NIH/NIAID U19AI057229-16; Stanford Maternal Child Health Research Institute; and Chan Zuckerberg Biohub (CAB).

The levels of inflammatory cytokines in COVID-19 patients are compared to patients with other critical illness, such as sepsis or acute respiratory distress syndrome.

Biomarkers associated with COVID-19 disease progression

The coronavirus disease 2019 (COVID-19) pandemic is a scientific, medical, and social challenge. The complexity of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is centered on the unpredictable clinical course of the disease that can rapidly develop, causing severe and deadly complications. The identification of effective laboratory biomarkers able to classify patients based on their risk is imperative in being able to guarantee prompt treatment. The analysis of recently published studies highlights the role of systemic vasculitis and cytokine mediated coagulation disorders as the principal actors of multi organ failure in patients with severe COVID-19 complications. The following biomarkers have been identified: hematological (lymphocyte count, neutrophil count, neutrophil-lymphocyte ratio (NLR)), inflammatory (C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), procalcitonin (PCT)), immunological (interleukin (IL)-6 and biochemical (D-dimer, troponin, creatine kinase (CK), aspartate aminotransferase (AST)), especially those related to coagulation cascades in disseminated intravascular coagulation (DIC) and acute respiratory distress syndrome (ARDS). New laboratory biomarkers could be identified through the accurate analysis of multicentric case series; in particular, homocysteine and angiotensin II could play a significant role.

COVID-19 Patients with Pulmonary Fibrotic Tissue: Clinical Pharmacological Rational of Antifibrotic Therapy

In December 2019, the first data emerged from Wuhan, China, of a serious acute respiratory disease caused by a new coronavirus, SARS-CoV-2 (COVID-19). In a short time, the health emergency became a global pandemic. To date, there are about 18.8 million infected people and about 700,000 deaths. There are currently no effective vaccines, and treatments are mostly experimental. The symptoms associated with COVID-19 are different, ranging from mild upper respiratory tract symptoms to severe acute respiratory distress syndrome (SARS). Data from previous coronavirus outbreaks such as SARS-CoV (2003 outbreak) and emerging epidemiological data from the current global COVID-19 pandemic suggest that there could be substantial tissue fibrotic consequences following SARS-CoV-2 infection, responsible for severe and in some cases fatal lung lesions. Some data show that even patients cured of viral infection have lung fibrotic tissue residues responsible for incorrect respiratory function even after healing. The role of antifibrotic drug therapy in patients with ongoing SARS-CoV-2 infection or in patients cured of residual pulmonary fibrosis is still to be defined and unclear; the scientific rationale for initiating, continuing, or discontinuing therapy is poorly defined. In this article, we describe the advantages of antifibrotic therapy in patients with ongoing SARS-CoV-2 viral infection to prevent the worsening and aggravation of the clinical situation, and the advantages it could have in the role of preventing pulmonary fibrosis after SARS-CoV-2 infection, and in accelerating the complete healing process.

IFN signaling and neutrophil degranulation transcriptional signatures are induced during SARS-CoV-2 infection

The novel virus SARS-CoV-2 has infected more than 14 million people worldwide resulting in the Coronavirus disease 2019 (COVID-19). Limited information on the underlying immune mechanisms that drive disease or protection during COVID-19 severely hamper development of therapeutics and vaccines. Thus, the establishment of relevant animal models that mimic the pathobiology of the disease is urgent. Rhesus macaques infected with SARS-CoV-2 exhibit disease pathobiology similar to human COVID-19, thus serving as a relevant animal model. In the current study, we have characterized the transcriptional signatures induced in the lungs of juvenile and old rhesus macaques following SARS-CoV-2 infection. We show that genes associated with Interferon (IFN) signaling, neutrophil degranulation and innate immune pathways are significantly induced in macaque infected lungs, while pathways associated with collagen formation are downregulated. In COVID-19, increasing age is a significant risk factor for poor prognosis and increased mortality. We demonstrate that Type I IFN and Notch signaling pathways are significantly upregulated in lungs of juvenile infected macaques when compared with old infected macaques. These results are corroborated with increased peripheral neutrophil counts and neutrophil lymphocyte ratio in older individuals with COVID-19 disease. In contrast, pathways involving VEGF are downregulated in lungs of old infected macaques. Using samples from humans with SARS-CoV-2 infection and COVID-19, we validate a subset of our findings. Finally, neutrophil degranulation, innate immune system and IFN gamma signaling pathways are upregulated in both tuberculosis and COVID-19, two pulmonary diseases where neutrophils are associated with increased severity. Together, our transcriptomic studies have delineated disease pathways to improve our understanding of the immunopathogenesis of COVID-19 to facilitate the design of new therapeutics for COVID-19.

Macrophage activation syndrome and COVID-19

An emerging, rapidly spreading coronavirus SARS-CoV-2 is causing a devastating pandemic. As we have not developed curative medicine and effective vaccine, the end of this life-threatening infectious disease is still unclear. Severe COVID-19 is often associated with hypercytokinemia, which is typically found in macrophage activation syndrome. SARS-CoV-2 infection causes this strong inflammation within the lung and propagates to respiratory and, ultimately, systemic organ malfunction. Although we have not fully understood the physiological and pathological aspects of COVID-19, current research progress indicates the effectiveness of anti-cytokine therapy. Here, we summarize macrophage activation syndrome and its possible contribution to COVID-19, and cytokine targeted attempts in severe COVID-19 cases.

A gendered magnifying glass on COVID-19

COVID-19 pandemia is affecting Countries worldwide with a gendered death excess as being a male represents, especially in the 50-69 years age group, an unfavourable factor. Females are constitutionally prone to defend themselves against pathogens with a stronger efficiency than males. As a fact, several genes involved into the regulation of the innate and adaptive immune response are strategically placed on the X-chromosome and, among them, pathogen-related receptors (PRRs), such as Toll-like receptor 7, suitable to recognize ssRNAs and trigger a gendered successful anti-viral fight. On the other hand, a more regulated IL-6 production and a more contained inflammation after the encounter of a pathogen supply score points in favour of the female sex in the view that an abnormal and exaggerated cytokine release does represent the hallmark of the deathful SARS-CoV-2 infection. The sex-prevalent expression of the attachment and permissive molecules ACE2 and TMPRSS2 further supports the concept of a male-oriented vulnerability. In this review, the possible role of biological and immunological sex differences into the higher morbidity and mortality of SARS-CoV-2 between females and males are discussed.

Pharmacological management of COVID-19 patients with ARDS (CARDS): A narrative review

Coronavirus disease 2019 (COVID-19) is highly infectious. It has been highlighted that if not expertly and individually managed with consideration of the vasocentric features, a COVID-19 patient with an acute respiratory distress syndrome (CARDS) may eventually develop multiorgan failure. Unfortunately, there is still no definite drug for CARDS that is capable of reducing either short-term or long-term mortality and no specific treatments for COVID-19 exist right now. In this narrative review, based on a selective literature search in EMBASE, MEDLINE, Scopus, The Cochrane Library, Web of Science, and Google Scholar and ClinicalTrials.gov, we have examined the emerging evidence on the possible treatment of CARDS. Although numerous pharmacologic therapies to improve clinical outcomes in CARDS have been studied also in clinical trials, none have shown efficacy and there is great uncertainty about their effectiveness. There is still no recommendation for the therapeutic use of any specific agent to treat CARDS because no drugs are validated to have significant efficacy in clinical treatment of COVID-19 patients in large-scale trials. However, there exist a number of drugs that may be useful at least in some patients. The real challenge now is to link the right patient to the right treatment.

Lycorine attenuates lipopolysaccharide-induced acute lung injury through the HMGB1/TLRs/NF-κB pathway

Lung injury associated with systemic inflammatory response is a common problem affecting human health. Previous studies have shown that lycorine exerts a anti-inflammatory effect. However, whether lycorine alleviates lung injury remains unclear. To explore this issue, BALB/c mice and MLE-12 cells were treated with lipopolysaccharide (LPS) to establish lung injury mouse model and cell model, respectively. Glycyrrhizic acid, known as an inhibitor of ALI, was also used to study the effects of lycorine in vitro. Our results showed that after LPS treatment, the lung injury score, lung wet-to-dry weight ratio, and malondialdehyde (MDA) production in the lung tissues and the expression levels of tumor necrosis factor-α, interleukin-1β, and interleukin-6 in bronchoalveolar lavage fluid were significantly increased, whereas their levels were decreased by lycorine. Additionally, LPS injection activated the high-mobility group box 1 (HMGB1)/Toll-like receptors (TLRs)/NF-κB pathway. However, lycorine treatment attenuated the activity of the HMGB1/TLRs/NF-κB pathway in the lung tissues. In vitro studies showed that lycorine administration significantly decreased the levels of inflammatory cytokines and MDA and attenuated the activity of the HMGB1/TLRs/NF-κB pathway in LPS-treated cells. Moreover, the inhibitory effects of lycorine on the inflammatory response and oxidative stress in LPS-treated lung cells were similar with that of glycyrrhizic acid, and this inhibition was intensified by both lycorine and glycyrrhizic acid treatment. We suggest that lycorine could alleviate LPS-induced lung injury of inflammation and oxidative stress by blocking the HMGB1/TLRs/NF-κB pathway, which gives a new perspective for ALI therapy to treat lycorine as a potential treatment clinically.

Pulmonary fibrosis and COVID-19: the potential role for antifibrotic therapy

In December, 2019, reports emerged from Wuhan, China, of a severe acute respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). By the end of April, 2020, over 3 million people had been confirmed infected, with over 1 million in the USA alone, and over 215 000 deaths. The symptoms associated with COVID-19 are diverse, ranging from mild upper respiratory tract symptoms to severe acute respiratory distress syndrome. The major risk factors for severe COVID-19 are shared with idiopathic pulmonary fibrosis (IPF), namely increasing age, male sex, and comorbidities such as hypertension and diabetes. However, the role of antifibrotic therapy in patients with IPF who contract SARS-CoV-2 infection, and the scientific rationale for their continuation or cessation, is poorly defined. Furthermore, several licensed and potential antifibrotic compounds have been assessed in models of acute lung injury and viral pneumonia. Data from previous coronavirus infections such as severe acute respiratory syndrome and Middle East respiratory syndrome, as well as emerging data from the COVID-19 pandemic, suggest there could be substantial fibrotic consequences following SARS-CoV-2 infection. Antifibrotic therapies that are available or in development could have value in preventing severe COVID-19 in patients with IPF, have the potential to treat severe COVID-19 in patients without IPF, and might have a role in preventing fibrosis after SARS-CoV-2 infection.

Systemic Markers of Monocyte Activation in Acute Pulmonary Oedema

BACKGROUND

Hydrostatic lung injury followed by pulmonary remodelling variably complicates cardiogenic acute pulmonary oedema (APO). Pulmonary remodelling may be regulated by the balance between distinct phenotypes of pulmonary macrophages; activated/inflammatory (M1), and reparative/anti-inflammatory (M2), derived from circulating monocyte populations. The aim of this study was to identify biomarkers in peripheral blood that are consistent with hydrostatic lung injury and pulmonary remodelling in APO and which follow the variable clinical course.

METHODS

To examine peripheral markers of lung inflammation, resolution and remodelling, 18 patients, admitted to the intensive care unit (ICU) with a clinical diagnosis of APO, were enrolled. Admission, 12- and 24-hour post-admission bloods were assayed for cytokines by ELISA (R&D Systems, Minneapolis, MN, USA) and leukocyte surface markers by flow cytometry.

RESULTS

Admission PaO₂ to FiO₂ ratio was positively correlated with Mon 2 (intermediate) monocyte prevalence, through increasing ratio of CD16⁺ monocytes to CD11b⁺ and CD40⁺ monocytes, and negatively correlated with Mon 1 (classical) monocyte prevalence, through decreasing ratio of CD16⁺ monocytes to CD62L⁺. Secondary cohort analysis compared 10 APO patients with established chronic heart failure (CHF) to eight without CHF. An increase in monocyte chemotactic peptide (MCP)-1, monocyte prevalence, and CD16^-CD62L⁺ monocytes with CHF, all characteristic of monocyte activation to a Mon 1 phenotype, were found in the CHF APO patients.

CONCLUSIONS

Increased systemic monocyte prevalence and expression of cell surface markers suggest a Mon 1 profile in CHF patients during episodes of APO. Future studies should define the role of systemic monocyte prevalence and activation in decompensated CHF.

Pulmonary fibrosis in the aftermath of the COVID-19 era (Review)

The year 2020 is characterized by the COVID-19 pandemic that has resulted in more than half a million deaths in recent months. The high mortality is associated with acute severe respiratory failure that results in ICU admission and intubation. While facing this fatal disease, research and clinical observations need to be carried out in order to evaluate the long-term effects of the COVID-19 acute respiratory distress syndrome (ARDS). Potent clinical and laboratory biomarkers should be studied to be able to predict the subgroup of patients that are going to deteriorate or develop lung fibrosis. The opportunity of personalized medicine is a good way to consider for these patients.