Epidemiology of acute lung injury

The Predictive Validity of the Berlin Definition of Acute Respiratory Distress Syndrome for Patients With COVID-19-Related Respiratory Failure Treated With High-Flow Nasal Oxygen: A Multicenter, Prospective Cohort Study

OBJECTIVES

The Berlin definition of acute respiratory distress syndrome (ARDS) was constructed for patients receiving invasive mechanical ventilation (IMV) with consideration given to issues related to reliability, feasibility, and validity. Notwithstanding, patients with acute respiratory failure (ARF) may be treated with high-flow nasal oxygen (HFNO) and may not fall within the scope of the original definition. We aimed to evaluate the predictive validity of the Berlin definition in HFNO-treated patients with COVID-19-related respiratory failure who otherwise met ARDS criteria.

DESIGN

Multicenter, prospective cohort study.

SETTING

Five ICUs of five centers in Argentina from March 2020 to September 2021.

PATIENTS

We consecutively included HFNO-treated patients older than 18 years with confirmed COVID-19-related ARF, a Pa o2 /F io2 of less than 300 mm Hg, bilateral infiltrates on imaging, and worsening respiratory symptoms for less than 1 week.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We evaluated the predictive validity of mortality at day 28 using the area under the receiver operating characteristics curve (AUC), compared the predictive validity across subgroups, and characterized relevant clinical outcomes. We screened 1,231 patients and included 696 ARDS patients [30 (4%) mild, 380 (55%) moderate, and 286 (41%) severe]. For the study cohort, the AUC for mortality at day 28 was 0.606 (95% CI, 0.561-0.651) with the AUC for subgroups being similar to that of the overall cohort. Two hundred fifty-six patients (37%) received IMV. By day 28, 142 patients (21%) had died, of whom 81 (57%) had severe ARDS. Mortality occurred primarily in patients who were transitioned to IMV.

CONCLUSIONS

The predictive validity of the Berlin ARDS definition was similar for HFNO-treated patients as compared with the original population of invasively ventilated patients. Our findings support the extension of the Berlin definition to HFNO-treated patients with ARDS.

Intravenous Autologous Bone Marrow-derived Mesenchymal Stromal Cells Delay Acute Respiratory Distress Syndrome in Swine

Rationale: Early post injury mitigation strategies in ARDS are in short supply. Treatments with allogeneic stromal cells are administered after ARDS develops, require specialized expertise and equipment, and to date have shown limited benefit. Objectives: Assess the efficacy of immediate post injury intravenous administration of autologous or allogeneic bone marrow-derived mesenchymal stromal cells (MSCs) for the treatment of acute respiratory distress syndrome (ARDS) due to smoke inhalation and burns. Methods: Yorkshire swine (n = 32, 44.3 ± 0.5 kg) underwent intravenous anesthesia, placement of lines, severe smoke inhalation, and 40% total body surface area flame burns, followed by 72 hours of around-the-clock ICU care. Mechanical ventilation, fluids, pressors, bronchoscopic cast removal, daily lung computed tomography scans, and arterial blood assays were performed. After injury and 24 and 48 hours later, animals were randomized to receive autologous concentrated bone marrow aspirate (n = 10; 3 × 106 white blood cells and a mean of 56.6 × 106 platelets per dose), allogeneic MSCs (n = 10; 6.1 × 106 MSCs per dose) harvested from healthy donor swine, or no treatment in injured control animals (n = 12). Measurements and Main Results: The intravenous administration of MSCs after injury and at 24 and 48 hours delayed the onset of ARDS in swine treated with autologous MSCs (48 ± 10 h) versus control animals (14 ± 2 h) (P = 0.004), reduced ARDS severity at 24 (P < 0.001) and 48 (P = 0.003) hours, and demonstrated visibly diminished consolidation on computed tomography (not significant). Mortality at 72 hours was 1 in 10 (10%) in the autologous group, 5 in 10 (50%) in the allogeneic group, and 6 in 12 (50%) in injured control animals (not significant). Both autologous and allogeneic MSCs suppressed systemic concentrations of TNF-α (tumor necrosis factor-α). Conclusions: The intravenous administration of three doses of freshly processed autologous bone marrow-derived MSCs delays ARDS development and reduces its severity in swine. Bedside retrieval and administration of autologous MSCs in swine is feasible and may be a viable injury mitigation strategy for ARDS.

Yinma Jiedu Granule attenuates LPS-induced acute lung injury in rats via suppressing inflammation level

ETHNOPHARMACOLOGICAL RELEVANCE

Yinma Jiedu Granule (YMJD) is a traditional Chinese patent medicine (CPM), which has been proved to have anti-inflammatory effects and therapeutical effects on obstructive pulmonary disease.

AIM OF STUDY

The purpose of the current investigation is to find out if YMJD can alleviate acute lung injury (ALI) induced by lipopolysaccharide (LPS) in rats and its underlying mechanisms.

MATERIALS AND METHODS

Rats were treated with either vehicle or YMJD for 14 consecutive days, and 2 h after the last administration, the rat model of ALI was induced by the intratracheal instillation of LPS. High performance liquid chromatography (HPLC) was applied for the fingerprint analysis of YMJD. The efficacy and molecular mechanisms were investigated.

RESULTS

The results showed that treatment with YMJD improved the general state of rats, reduced weight loss and serum lactate (LA) levels, attenuated pulmonary edema and pathological damage of the lung tissue. Moreover, we found that YMJD effectively decreased the infiltration of white blood cells (WBC), lymphocytes (LYM), mononuclear cells (MON) and neutrophils (NEUT) in bronchoalveolar lavage fluid (BALF), reduced the concentration of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) and inhibited inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in the lung tissue. Additionally, we found that YMJD could significantly increase the activity of superoxide dismutase (SOD) and reduce the malondialdehyde (MDA) level in the lung tissue. By employing RNA-sequencing, we have identified that JAK2/STAT1 is an important pathway that is involved in the lung protection of YMJD, and further Western blot assay verified that YMJD could effectively inhibit the activation of the JAK2/STAT1 pathway.

CONCLUSIONS

YMJD could attenuate LPS-induced ALI through suppressing inflammation and oxidative stress in the lung tissue of rats, associating with the inhibition of JAK2/STAT1 activation. These findings provide evidence for the clinical use of YMJD for treatment of inflammatory pulmonary diseases like ALI.

Rethinking Acute Respiratory Distress Syndrome after COVID-19: If a "Better" Definition Is the Answer, What Is the Question?

The definition of acute respiratory distress syndrome (ARDS) has a somewhat controversial history, with some even questioning the need for the term "ARDS." This controversy has been amplified by the coronavirus disease (COVID-19) pandemic given the marked increase in the incidence of ARDS, the relatively new treatment modalities that do not fit neatly with the Berlin definition, and the difficulty of making the diagnosis in resource-limited settings. We propose that attempts to revise the definition of ARDS should apply the framework originally developed by psychologists and social scientists and used by other medical disciplines to generate and assess definitions of clinical syndromes that do not have gold standards. This framework is structured around measures of reliability, feasibility, and validity. Future revisions of the definition of ARDS should contain the purpose, the methodology, and the framework for empirically testing any proposed definition. Attempts to revise critical illness syndromes' definitions usually hope to make them "better"; our recommendation is that future attempts use the same criteria used by other fields in defining what "better" means.

Selected Phytochemicals to Combat Lungs Injury: Natural Care

The human has two lungs responsible for respiration and drug metabolism. Severe lung infection caused by bacteria, mycobacteria, viruses, fungi, and parasites may lead to lungs injury. Smoking and tobacco consumption may also produce lungs injury. Inflammatory and pain mediators are secreted by alveolar macrophages. The inflammatory mediators, such as cytokines, interleukin (IL)-1, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF)-α, neutrophils, and fibroblasts are accumulated in the alveoli sac, which becomes infected. It may lead to hypoxia followed by severe pulmonary congestion and the death of the patient. There is an urgent need for the treatment of artificial respiration and ventilation. However, the situation may be the worst for patients suffering from lung cancer, pulmonary tuberculosis, and acute pneumonia caused by acute respiratory distress syndrome (ARDS). Re-urgency has been happening in the case of coronavirus disease of 2019 (COVID-19) patients. Therefore, it is needed to protect the lungs with the intake of natural phytomedicines. In the present review, several selected phyto components having the potential role in lung injury therapy have been discussed. Regular intake of natural vegetables and fruits bearing these constituents may save the lungs even in the dangerous attack of SARS-CoV-2 in lung cancer, pulmonary TB, and pneumatic patients.

Emerging roles of fibroblast growth factor 21 in critical disease

In spite of the great progress in the management of critical diseases in recent years, its associated prevalence and mortality of multiple organ failure still remain high. As an endocrine hormone, fibroblast growth factor 21 (FGF21) functions to maintain homeostasis in the whole body. Recent studies have proved that FGF21 has promising potential effects in critical diseases. FGF21 has also been found to have a close relationship with the progression of critical diseases and has a great predictive function for organ failure. The level of FGF21 was elevated in both mouse models and human patients with sepsis or other critical illnesses. Moreover, it is a promising biomarker and has certain therapeutic roles in some critical diseases. We focus on the emerging roles of FGF21 and its potential effects in critical diseases including acute lung injury/acute respiratory distress syndrome (ALI/ARDS), acute myocardial injury (AMI), acute kidney injury (AKI), sepsis, and liver failure in this review. FGF21 has high application value and is worth further studying. Focusing on FGF21 may provide a new perspective for the management of the critical diseases.

High-Flow Nasal Oxygen for Severe Hypoxemia: Oxygenation Response and Outcome in Patients with COVID-19

Rationale: The "Berlin definition" of acute respiratory distress syndrome (ARDS) does not allow inclusion of patients receiving high-flow nasal oxygen (HFNO). However, several articles have proposed that criteria for defining ARDS should be broadened to allow inclusion of patients receiving HFNO. Objectives: To compare the proportion of patients fulfilling ARDS criteria during HFNO and soon after intubation, and 28-day mortality between patients treated exclusively with HFNO and patients transitioned from HFNO to invasive mechanical ventilation (IMV). Methods: From previously published studies, we analyzed patients with coronavirus disease (COVID-19) who had PaO2/FiO2 of ⩽300 while treated with ⩾40 L/min HFNO, or noninvasive ventilation (NIV) with positive end-expiratory pressure of ⩾5 cm H2O (comparator). In patients transitioned from HFNO/NIV to invasive mechanical ventilation (IMV), we compared ARDS severity during HFNO/NIV and soon after IMV. We compared 28-day mortality in patients treated exclusively with HFNO/NIV versus patients transitioned to IMV. Measurements and Main Results: We analyzed 184 and 131 patients receiving HFNO or NIV, respectively. A total of 112 HFNO and 69 NIV patients transitioned to IMV. Of those, 104 (92.9%) patients on HFNO and 66 (95.7%) on NIV continued to have PaO2/FiO2 ⩽300 under IMV. Twenty-eight-day mortality in patients who remained on HFNO was 4.2% (3/72), whereas in patients transitioned from HFNO to IMV, it was 28.6% (32/112) (P < 0.001). Twenty-eight-day mortality in patients who remained on NIV was 1.6% (1/62), whereas in patients who transitioned from NIV to IMV, it was 44.9% (31/69) (P < 0.001). Overall mortality was 19.0% (35/184) and 24.4% (32/131) for HFNO and NIV, respectively (P = 0.2479). Conclusions: Broadening the ARDS definition to include patients on HFNO with PaO2/FiO2 ⩽300 may identify patients at earlier stages of disease but with lower mortality.

Population enrichment for critical care trials: phenotypes and differential outcomes

PURPOSE OF REVIEW

Sepsis and acute respiratory distress syndrome (ARDS) are two heterogenous acute illnesses where numerous RCTs have indeterminate results. We present a narrative review on the recent developments in enriching patient populations for future sepsis and ARDS trials.

RECENT FINDINGS

Many researchers are actively pursuing enrichment strategies to reduce heterogeneity to increase the sensitivity of future trials. Enrichment refers to the use of measurable patient characteristics, known before randomisation, to refine trial populations. Biomarkers could increase the diagnostic certainty of sepsis, whereas chest radiology training to enhance reliability of interpretation and stabilisation period of mechanical ventilation have been considered to increase the diagnostic certainty of ARDS. Clinical and biomarker data analyses identifies four to six sepsis clinical phenotypes and two ARDS clinical phenotypes. Similarly, leukocyte gene expression data identifies two to four sepsis molecular phenotypes. Use of a test-dose identifies ARDS subpopulations who are likely to benefit from higher PEEP. Early-phase trials report how a biomarker that is altered by the intervention, such as lymphocyte count for recombinant interleukin-7 therapy and higher check point inhibitor expression for anti-check point treatments in sepsis, could identify a higher treatment effect population for future trials.

SUMMARY

Enrichment reduces heterogeneity and will enhance the sensitivity of future trials. However, enrichment, even when it identifies more homogenous populations, may not be efficient to deploy in trials or clinical practice.

External validity of Adult Sepsis Event's simplified eSOFA criteria: a retrospective analysis of patients with confirmed infection in China

Background

The US Centers for Disease Control and Prevention (CDC) recently released simplified eSOFA organ dysfunction criteria of Adult Sepsis Event for sepsis surveillance in the US. Our study aimed to compare the prevalence, characteristics, and outcomes of sepsis patients identified by eSOFA criteria versus Sequential Organ Failure Assessment (SOFA) Score (Sepsis-3) and assess the external validity of eSOFA criteria in China.

Methods

We conducted a retrospective cohort study of adult residents of Yuetan Subdistrict, Beijing, China, who were hospitalized from July 1, 2012 to June 30, 2014. Among patients with infection, sepsis was identified if there was a concurrent rise in SOFA score by 2 or more points (Sepsis-3) or the presence of 1 or more eSOFA criteria: vasopressor initiation, mechanical ventilation initiation, doubling in creatinine, doubling in bilirubin to 2.0 mg/dL or above, 50% or greater decrease in platelet count to less than 100 cells/μL, or lactate equal to or above 2.0 mmol/L. Areas under the receiver operating characteristic curves (AUROCs) for in-hospital mortality were compared between sepsis patients detected by the two criteria, adjusting for baseline characteristics.

Results

Of 1716 hospitalized patients with infection, 935 (54.5%) met Sepsis-3 criteria, 573 (33.4%) met eSOFA criteria, while 475 (27.7%) met both criteria. Demographic and clinical characteristics of sepsis patients meeting Sepsis-3 or eSOFA criteria were similar. In-hospital mortality was higher with eSOFA criteria versus Sepsis-3 (46.6% vs. 32.0%, p < 0.001). eSOFA criteria had high PPV (82.9%), but low sensitivity (50.8%) for the diagnosis of Sepsis-3. Patients meeting both criteria had the highest in-hospital mortality rate (52.8%, all p < 0.001), while patients who only met eSOFA criteria had higher mortality rate than those meeting Sepsis-3 alone (16.3% vs. 10.4%, p = 0.097). The predicted probability for in-hospital mortality was higher with eSOFA criteria versus Sepsis-3 (AUROC 0.830 vs. 0.795, p = 0.001) adjusting for baseline characteristics.

Conclusions

The CDC Adult Sepsis Event’s eSOFA criteria identify a smaller, more severely ill cohort of sepsis patients with similar demographic and clinical characteristics as the more complex Sepsis-3 SOFA score. These results suggest similar performance of eSOFA criteria across diverse populations, with low sensitivity and high specificity for the diagnosis of Sepsis-3.

Shikonin improve sepsis-induced lung injury via regulation of miRNA-140-5p/TLR4-a vitro and vivo study

Shikonin is an anti-inflammatory agent extracted from natural herbs. The aim of this study is to explain the treatment effects and mechanism of Shikonin in acute lung injury induced by sepsis. In this study, first, we evaluate different Shikonin concentrations for the anti-inflammation of acute lung injury induced by sepsis in an in vivo study. On the basis of the results, we confirm that 50.0 mg/kg was the best therapeutic Shikonin concentration. As a second step, we discuss the mechanism of Shikonin by a vitro cell experiment. Finaly, we validate that Shikonin has effective treatment effects on acute lung injury via regulation of microRNA-140-5p/toll-like receptor 4 (miRNA-140-5p/TLR4) in the in vivo study. The results of vitro and vivo study showed that Shikonin could improve acute lung injury induced by sepsis. The mechanism might be correlation miRNA-140-5p expression increasing, and regulated targeted gene TLR4, with TLR4 expression depressing, the downstream myeloid differentiation protein 88 and nuclear factor κB proteins expression were suppressed. In conclusion, Shikonin improved sepsis induced lung injury by regulation miRNA-140-5p/TLR4.

Ventilation-Like Mechanical Strain Modulates the Inflammatory Response of BEAS2B Epithelial Cells

Protective mechanical ventilation is aimed at preventing ventilator-induced lung injury while ensuring sufficient gas exchange. A new approach focuses on the temporal profile of the mechanical ventilation. We hypothesized that the temporal mechanical strain profile modulates inflammatory signalling. We applied cyclic strain with various temporal profiles to human bronchial epithelial cells (BEAS2B) and assessed proinflammatory response. The cells were subjected to sinusoidal, rectangular, or triangular strain profile and rectangular strain profile with prestrain set to 0, 25, 50, or 75% of the maximum stain, static strain, and strain resembling a mechanical ventilation-like profile with or without flow-controlled expiration. The BEAS2B response to mechanical load included altered mitochondrial activity, increased superoxide radical levels, NF-kappaB translocation, and release of interleukin-8. The response to strain was substantially modulated by the dynamics of the stimulation pattern. The rate of dynamic changes of the strain profile correlates with the degree of mechanical stress-induced cell response.

Inflammatory and Fibrinolytic System in Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is the most advanced form of acute lung injury (ALI). This is characterized by bilateral pulmonary infiltrates and severe hypoxemia. According to Berlin definition of ARDS, this is defined based on the timings, radiographic changes, edema formation, and severity on the PaO₂/FiO₂ ratio. During ARDS, the loss of integrity of the epithelium causes the septic shock. The degree of epithelial injury is the major prognostic marker of ARDS. In addition to this, inflammatory cell migration, fibro-proliferation, and activation of apoptosis also play an important role in the pathophysiology of ARDS. The alveolar epithelial cell is the prime target during injury where this cell either undergo apoptosis or epithelial-mesenchymal transition (EMT). Injury to the AECs triggers the changes in the DNA fragmentation and activation of certain apoptotic markers such as caspases at the same time some cells undergo biochemical changes and loses its epithelial morphology as well epithelial biomarkers and gain mesenchymal biomarkers and morphology. In both the cases, the fibrinolytic system plays an important role in maintaining the integrity of the disease process efficiently. This review highlights the research evidence of apoptosis and EMT in lung development, injury and its prognosis in ARDS thereby to develop an effective strategy for the treatment of ARDS.

Pediatric acute respiratory distress syndrome - current views

Acute respiratory distress syndrome (ARDS) mainly involves acute respiratory failure. In addition to this affected patients feel progressive arterial hypoxemia, dyspnea, and a marked increase in the work of breathing. The only clinical solution for the above pathological state is ventilation. Mechanical ventilation is necessary to support life in ARDs but it itself worsen lung injury and the term is known clinically as ‘ventilation induced lung injury’ (VILI). At the cellular level, respiratory epithelial cells are subjected to cyclic stretch, i.e. repeated cycles of positive and negative strain, during normal tidal ventilation. In aerated areas of diseased lungs, or even normal lungs subjected to injurious positive pressure mechanical ventilation, the cells are at risk of being over distended, and worsening injury by disrupting the alveolar epithelial barrier. Further, hypercapnic acidosis (HCA) in itself confers protection from stretch injury, potentially via a mechanisms involving inhibition of nuclear factor κB (NF-κB), a transcription factor central to inflammation, injury and repair. Mesenchymal stem cells are the latest in the field and are being investigated as a possible therapy for ARDS.

Fifty Years of Research in ARDS. The Epidemiology of Acute Respiratory Distress Syndrome. A 50th Birthday Review

Since its first description 50 years ago, no other intensive care syndrome has been as extensively studied as acute respiratory distress syndrome (ARDS). Despite this extensive body of research, many basic epidemiologic questions remain unsolved. The lack of gold standard tests jeopardizes accurate diagnosis and translational research. Wide variation in the population incidence has been reported, making even simple estimates of the burden of disease problematic. Despite these limitations, there has been an increase in the understanding of pathophysiology and important risk factors both for the development of ARDS and for important patient-centered outcomes like mortality. In this Critical Care Perspective, we discuss the historical context of ARDS description and attempts at its definition. We highlight the epidemiologic challenges of studying ARDS, as well as other intensive care syndromes, and propose solutions to address them. We update the current knowledge of ARDS trends in incidence and mortality, risk factors, and recently described endotypes.

Usefulness of 1,3 Beta-D-Glucan Detection in non-HIV Immunocompromised Mechanical Ventilated Critically Ill Patients with ARDS and Suspected Pneumocystis jirovecii Pneumonia

INTRODUCTION

Pneumocystis jirovecii pneumonia (PCP) is a major cause of disease in immunocompromised individuals. Diagnosis is typically obtained by microscopy and/or PCR. For ambiguous PCR results, we evaluated the new biomarker 1,3-Beta-D-Glucan (BDG).

METHODS

BDG serum levels were assessed and correlated to PCR results in immunosuppressed patients with ARDS.

RESULTS

11 (22%) out of 50 patients had suspected PCP. APACHE II (26 vs. 24; p < 0.002), SOFA score (16 vs. 14; p < 0.010) and mortality rate (34 vs. 69% p < 0.004; 34 vs. 80% p < 0.003) were significantly altered in patients with positive (pPCR) and slightly positive (spPCR) PCJ PCR as compared to patients with no-PCP (nPCP). BDG levels were significantly lower in patients with nPCP (86; 30-315 pg/ml) than in patients with pPCR (589; 356-1000 pg/ml; p < 0.001) and spPCP (398; 297-516 pg/ml; p < 0.004) referring to the cutoff in this study for PCP of 275 pg/ml. An overall sensitivity (S) of 92% (95% CI 86-96%) and specificity (SP) of 84% (95% CI 79-85%) for PCP were found for the BDG Fungitell assay. In detail, S of 98% (95% CI 94-100%) and SP of 86% (95% CI 82-92%) for pPCP and S of 98% (95% CI 96-100%) and SP of 88% (95% CI 86-96%) for spPCO were found.

CONCLUSION

Serum BDG levels were strongly elevated in PCP, and the negative predictive value is high. BDG could be used as a preliminary test for patients with suspected PCP, especially in patients with slightly positive PCR results.

Pneumonitis and pneumonia after aspiration

Aspiration pneumonitis and aspiration pneumonia are clinical syndromes caused by aspiration. These conditions are clinically significant due to their high morbidity and mortality. However, aspiration as a preceding event are often unwitnessed, particularly in cases of asymptomatic or silent aspiration. Furthermore, despite the difference in treatment approaches for managing aspiration pneumonitis and aspiration pneumonia, these two disease entities are often difficult to discriminate from one another, resulting in inappropriate treatment. The use of unclear terminologies hinders the comparability among different studies, making it difficult to produce evidence-based conclusions and practical guidelines. We reviewed the most recent studies to define aspiration, aspiration pneumonitis, and aspiration pneumonia, and to further assess these conditions in terms of incidence and epidemiology, pathophysiology, risk factors, diagnosis, management and treatment, and prevention.

Sangxingtang inhibits the inflammation of LPS-induced acute lung injury in mice by down-regulating the MAPK/NF-κB pathway

In the present study, we investigated anti-inflammatory effects of Sangxingtang (SXT) on acute lung injury using a lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse model. The cell counting in the bronchoalveolar lavage fluid (BALF) was performed. The degree of lung edema was evaluated by measuring the wet/dry weight (W/D) ratio. The superoxidase dismutase (SOD) and myeloperoxidase (MPO) activities were assayed by SOD and MPO kits, respectively. The levels of inflammatory mediators, including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), were assayed by the enzyme-linked immunosorbent assay methods. Pathological changes of lung tissues were observed by Hematoxylin and eosin (HE) staining. The inflammatory signaling pathway-related proteins nuclear factor mitogen activated protein kinases (P38MAPK), extracellular regulated protein kinases (Erk), c-Jun N-terminal kinase (Jnk) and nuclear transcription factor (NF-κB) p65 expressions were measured by Western blotting. Our results showed that the treatment with the SXT markedly attenuated the inflammatory cell numbers in the BALF, decreased the levels of P-P38MAPK, P-Erk, P-Jnk and P-NF-κB p65 and the total protein levels in lungs, improved the SOD activity and inhibited the MPO activity. Histological studies demonstrated that SXT substantially reduced the LPS-induced neutrophils in lung tissues, compared with the untreated LPS group. In conclusion, our results indicated that SXT had protective effects on LPS-induced ALI in mice.

Electrical impedance tomography (EIT) for quantification of pulmonary edema in acute lung injury

Background

Assessment of pulmonary edema is a key factor in monitoring and guidance of therapy in critically ill patients. To date, methods available at the bedside for estimating the physiologic correlate of pulmonary edema, extravascular lung water, often are unreliable or require invasive measurements. The aim of the present study was to develop a novel approach to reliably assess extravascular lung water by making use of the functional imaging capabilities of electrical impedance tomography.

Methods

Thirty domestic pigs were anesthetized and randomized to three different groups. Group 1 was a sham group with no lung injury. Group 2 had acute lung injury induced by saline lavage. Group 3 had vascular lung injury induced by intravenous injection of oleic acid. A novel, noninvasive technique using changes in thoracic electrical impedance with lateral body rotation was used to measure a new metric, the lung water ratio_EIT, which reflects total extravascular lung water. The lung water ratio_EIT was compared with postmortem gravimetric lung water analysis and transcardiopulmonary thermodilution measurements.

Results

A significant correlation was found between extravascular lung water as measured by postmortem gravimetric analysis and electrical impedance tomography (r = 0.80; p < 0.05). Significant changes after lung injury were found in groups 2 and 3 in extravascular lung water derived from transcardiopulmonary thermodilution as well as in measurements derived by lung water ratio_EIT.

Conclusions

Extravascular lung water could be determined noninvasively by assessing characteristic changes observed on electrical impedance tomograms during lateral body rotation. The novel lung water ratio_EIT holds promise to become a noninvasive bedside measure of pulmonary edema.

Judging quality of current septic shock definitions and criteria

Septic shock definitions are being revisited. We assess the feasibility, reliability, and validity characteristics of the current definitions and criteria of septic shock. Septic shock is conceptualised as cardiovascular dysfunction, tissue perfusion and cellular abnormalities caused by infection. Currently, for feasibility, septic shock is identified at the bedside by using either hypotension or a proxy for tissue perfusion/cellular abnormalities (e.g., hyperlactatemia). We propose that concurrent presence of cardiovascular dysfunction and perfusion/cellular abnormalities could improve validity of septic shock diagnosis, as we are more likely to identify a patient population with all elements of the illness concept. This epidemiological refinement should not affect clinical care and may aid study design to identify illness-specific biomarkers and interventions.

Hesperetin attenuates ventilator-induced acute lung injury through inhibition of NF-κB-mediated inflammation

Hesperetin, a major bioflavonoid in sweet oranges and lemons, has been reported to have anti-inflammatory properties. However, the effect of hesperetin on ventilator-induced acute lung injury has not been studied. In present study, we investigated the protective effect of hesperetin on ventilator-induced acute lung injury in rats. Rats were orally administered hesperetin (10, 20, or 40mg/kg) two hour before acute lung injury was induced by mechanical ventilation. Rats were then randomly divided into six groups: the lung protective ventilation group (n=20, LV group), injurious ventilation group (n=20, HV group), vehicle-treated injurious ventilation group (n=20, LV+vehicle group), hesperetin (10mg/kg)-treated acute lung injury group (n=20, HV+Hsp (10mg)), hesperetin (20mg/kg)-treated acute lung injury group (n=20, HV+Hsp (20mg)), and hesperetin (40mg/kg)-treated acute lung injury group (n=20, HV+Hsp (40mg)). The lung tissues and bronchoalveolar lavage fluid were isolated for subsequent measurements. Treatment with hesperetin dramatically improved the histology of lung tissue, and reduced the wet/dry ratio, myeloperoxidase activity, protein concentration, and production of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β, and MIP-2 in the bronchoalveolar lavage fluid of rats with ventilator-induced acute lung injury. Additionally, our study indicated that this protective effect of hesperetin results from its ability to increase the expression of peroxisome proliferator-activated receptor (PPAR)-γ and inhibit the activation of the nuclear factor (NF)-κB pathway. These results suggest that hesperetin may be a potential novel therapeutic candidate for protection against ventilator-induced acute lung injury.

Timosaponin B-II inhibits lipopolysaccharide-induced acute lung toxicity via TLR/NF-κB pathway

Timosaponin B-II (TB), a main bioactive compound in Anemarrhena asphodeloides Bunge, has various kinds of pharmacological activities, the present study aimed to investigate the protective role of TB on lipopolysaccharide (LPS)-induced acute lung injury (ALI). ALI was induced in mice by intratracheal instillation of LPS, and TB (20 and 60 mg/kg) was given orally 1 h prior to LPS administration. After 6 h, bronchoalveolar lavagefluid (BALF) and lung tissue were collected. TB decreased LPS-induced evident lung histopathological changes, lung wet-to-dry weight (W/D) ratio and lung myeloperoxidase (MPO) activity. In addition, TB inhibited inflammatory cells and cytokines including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in BALF. Furthermore, we demonstrated that TB inhibited the Toll-like receptor-2 (TLR2), Toll-like receptor-4 (TLR4), myeloid differentiation primary response gene-88 (MyD88), nuclear factor-κB (NF-κB) p65 in LPS-induced ALI. These results showed that administration of TB prior to LPS improves ALI, possibly mediating ALI through suppressing TLR/NF-κB pathway activation.

Eriodictyol, a plant flavonoid, attenuates LPS-induced acute lung injury through its antioxidative and anti-inflammatory activity

Acute lung injury (ALI) is characterized by excessive inflammatory responses and oxidative injury in the lung tissue. It has been suggested that anti-inflammatory or antioxidative agents could have therapeutic effects in ALI, and eriodictyol has been reported to exhibit antioxidative and anti-inflammatory activity in vitro. The aim of the present study was to investigate the effect of eriodictyol on lipopolysaccharide (LPS)-induced ALI in a mouse model. The mice were divided into four groups: Phosphate-buffered saline-treated healthy control, LPS-induced ALI, vehicle-treated ALI (LPS + vehicle) and eriodictyol-treated ALI (LPS + eriodictyol). Eriodictyol (30 mg/kg) was administered orally once, 2 days before the induction of ALI. The data showed that eriodictyol pretreatment attenuated LPS-induced ALI through its antioxidative and anti-inflammatory activity. Furthermore, the eriodictyol pretreatment activated the nuclear factor erythroid-2-related factor 2 (Nrf2) pathway in the ALI mouse model, which attenuated the oxidative injury and inhibited the inflammatory cytokine expression in macrophages. In combination, the results of the present study demonstrated that eriodictyol could alleviate the LPS-induced lung injury in mice by regulating the Nrf2 pathway and inhibiting the expression of inflammatory cytokines in macrophages, suggesting that eriodictyol could be used as a potential drug for the treatment of LPS-induced lung injury.

Tectorigenin inhibits the inflammation of LPS-induced acute lung injury in mice

AIM

In a previous study, the anti-inflammatory effects of tectorigenin were disclosed. In this study, the anti-inflammatory effects of tectorigenin on acute lung injury using a lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse model were investigated

METHOD

The cell-count in the bronchoalveolar lavage fluid (BALF) was measured. The animal lung edema degree was evaluated by the wet/dry weight (W/D) ratio. The superoxidase dismutase (SOD) activity and myeloperoxidase (MPO) activity was assayed using SOD and MPO kits, respectively. The levels of inflammatory mediators, including tumor necrosis factor-α (TNF-α), IL-1β, and IL-6 were assayed using an enzyme-linked immunosorbent assay method. Pathological changes of lung tissues were observed through HE staining. The inflammatory signal pathway related protein nuclear factor NF-κB p65 mRNA expression was measured by real-time PCR, and the protein level of NF-κB p65 was measured using Western blotting analysis.

RESULTS

The data showed that treatment with the tectorigenin markedly attenuated the inflammatory cell numbers in the BALF, decreased nuclear factor NF-κB p65 mRNA level and protein level in the lungs, and improved SOD activity and inhibited MPO activity. Histological studies showed that tectorigenin substantially inhibited LPS-induced neutrophils in lung tissue compared with the model group.

CONCLUSION

The results indicated that tectorigenin had a protective effect on LPS-induced ALI in mice.

Anti-inflammatory effects of water extract of Taraxacum mongolicum hand.-Mazz on lipopolysaccharide-induced inflammation in acute lung injury by suppressing PI3K/Akt/mTOR signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Taraxacum mongolicum Hand.-Mazz is a famous medicinal plant in China, has been listed in the Pharmacopoeia of the People's Republic of China and used to treat infection, fever, upper respiratory tract infection, pneumonia, and other infectious diseases. This study aims to evaluate the possible mechanisms responsible for the anti-inflammation effects of water extract of T. mongolicum Hand.-Mazz (WETMHM) on lipopolysaccharide (LPS)-induced inflammatory in acute lung injury.

MATERIALS AND METHODS

Female BALB/c mice were randomly divided into five groups with 10 mice in each group: (1) control group (saline), (2) LPS group, (3) LPS+dexamethasone (LPS+Dex, 2mg/kg, administered by gavage), (4) LPS+WETMHM (5 g/kg, administered by gavage), (5) LPS+WETMHM (10 g/kg, administered by gavage). The cell counting in the bronchoalveolar lavage fluid (BALF) was measured. The animal lung edema degree was evaluated by wet/dry weight (W/D) ratio. The superoxidase dismutase (SOD) activity and myeloperoxidase (MPO) activity were assayed by SOD and MPO kits, respectively. The levels of inflammation mediators including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 were assayed by an enzyme-linked immunosorbent assay method. Pathological changes of lung tissues were observed by hematoxylin and eosin (HE) staining. The levels of P-PI3K, PI3K, P-Akt, Akt, P-mTOR and mTOR were measured by Western blotting.

RESULTS

The data showed that treatment with the WETMHM inhibited LPS-induced inflammation: (1) WETMHM attenuated inflammation cell numbers in the BALF, (2) decreased protein levels of lung PI3K/Akt/mTOR, and (3) improved SOD activity and (4) inhibited MPO activity; (5) histological studies demonstrated that WETMHM substantially inhibited LPS-induced neutrophils in lung tissue.

CONCLUSION

The results indicated that the WETMHM had a protective effect on LPS-induced ALI in mice.

Conditioned media from adipose stromal cells limit lipopolysaccharide-induced lung injury, endothelial hyperpermeability and apoptosis

Background

Acute Respiratory Distress Syndrome (ARDS) is a condition that contributes to morbidity and mortality of critically ill patients. We investigated whether factors secreted by adipose stromal cells (ASC) into conditioned media (ASC-CM) will effectively decrease lung injury in the model of lipopolysaccharide (LPS)-induced ARDS.

Methods

To assess the effect of ASC-CM on ARDS indices, intravenous delivery of ASC and ASC-CM to C57Bl/6 mice was carried out 4 h after LPS oropharyngeal aspiration; Evans Blue Dye (EBD) was injected intravenously 1 h prior to animal sacrifice (48 h post-LPS). Lungs were either fixed for histopathology, or used to extract bronchoalveolar lavage fluid (BALF) or EBD. To assess the effect of ASC-CM on endothelial barrier function and apoptosis, human pulmonary artery endothelial cells were treated with ASC-CM for 48-72 h.

Results

ASC-CM markedly reduced LPS-induced histopathologic changes of lung, protein extravasation into BALF, and suppressed the secretion of proinflammatory cytokines TNFα and IL6. White Blood Cells (WBC) from BALF of LPS-challenged mice receiving ASC-CM had decreased reactive oxygen species (ROS) generation compared to WBC from LPS-challenged mice receiving control media injection. Treatment of pulmonary endothelial monolayers with ASC-CM significantly suppressed H₂O₂-induced leakage of FITC dextran and changes in transendothelial resistance, as well as gap formation in endothelial monolayer. ASC-CM exposure reduced the percentage of endothelial cells expressing ICAM-1, and suppressed TNFα-induced expression of E-selectin and cleavage of caspase-3. ASC-CM reduced the endothelial level of pro-apoptotic protein Bim, but did not affect the level of Bcl-2, Bad, or Bad phosphorylation.

Conclusions

Factors secreted by ASC efficiently reduce ARDS indices, endothelial barrier hyperpermeability, and activation of pro-inflammatory and pro-apoptotic pathways in endothelium.

Protective effect of p-cymene on lipopolysaccharide-induced acute lung injury in mice

In the previous study, the anti-inflammatory effect of p-cymene had been found. In this study, we investigated anti-inflammatory effects of p-cymene on acute lung injury using lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse model. The cell counting in the bronchoalveolar lavage fluid (BALF) was measured. The animal lung edema degree was evaluated by wet/dry weight (W/D) ratio. The superoxidase dismutase (SOD) activity and myeloperoxidase (MPO) activity was assayed by SOD and MPO kits, respectively. The levels of inflammatory mediators including tumor necrosis factor alpha (TNF-α), IL-1β, and IL-6 were assayed by enzyme-linked immunosorbent assay method. The pathological changes of the lung tissues were observed by hematoxylin and eosin staining. The inflammatory signal pathway-related protein levels of NF-κB were measured using Western blotting. The data showed that treatment with the p-cymene markedly attenuated inflammatory cell numbers in the BALF, decreased NF-κB protein level in the lungs, improved SOD activity, and inhibited MPO activity. Histological studies demonstrated that p-cymene substantially inhibited LPS-induced neutrophils in the lung tissue compared with the model group. The results indicated that p-cymene had a protective effect on LPS-induced ALI in mice.

Cepharanthine, an alkaloid from Stephania cepharantha Hayata, inhibits the inflammatory response in the RAW264.7 cell and mouse models

The aim of this study was to investigate the protective effects of cepharanthine (CEP) on inflammation in lipopolysaccharide (LPS)-stimulated RAW264.7 cells in vitro and a LPS-induced lung injury model in vivo. RAW264.7 cells were treated with various concentrations of CEP for 1 h followed by incubation with or without 1 μg/ml LPS for 18 h. TNF-α, IL-6, and IL-1β in the supernatants were measured by ELISA. Nuclear factor-κB (NF-κB) and mitogen-activated protein kinase pathways were analyzed by Western blot. Mice were randomly divided into control group, LPS group, CEP + LPS group, and dexamethasone + LPS group. A male BALB/c mouse model of acute lung injury was induced by LPS. Bronchoalveolar lavage fluid was collected for inflammatory cell count and cytokine assays. Histopathologic examination was performed on mice that were not subjected to bronchoalveolar lavage fluid collection. CEP dose-dependently inhibited the release of TNF-α, IL-6, and IL-1β in LPS-stimulated RAW264.7 cells. Significantly, CEP dose-dependently suppressed NF-κB activation, IκBα degradation, and phosphorylation of ERK, JNK, and p38 induced by LPS. In vivo, it was also observed that CEP attenuated lung histopathologic changes and down-regulated the level of pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6, in the mouse acute lung injury model. These results suggest that CEP potentially decreases inflammation in vitro and in vivo and might be a therapeutic agent against inflammatory diseases.

Impact of distinct definitions of acute lung injury on its incidence and outcomes in Brazilian ICUs: prospective evaluation of 7,133 patients*

OBJECTIVES

Evaluation of prevalence and outcomes of acute lung injury in a large cohort of critically ill patients in Brazil and comparison of predictive receiver operating characteristic curve mortality of American European Consensus conference definition with new Berlin definition of acute respiratory distress syndrome.

DESIGN

A 15-month prospective, multicenter, observational study.

SETTING

Fourteen medical ICUs in Espirito Santo, a state of Brazil.

PATIENTS

Mechanically ventilated patients who fulfilled American European Consensus conference criteria of acute lung injury or Berlin definition of acute respiratory distress syndrome.

INTERVENTIONS

Clinical and respiratory data were collected for 7 consecutive days and on the 14 and 28 days. Twenty-eight day mortality, hospital mortality, and predictive receiver operating characteristic curve mortality were calculated.

MEASUREMENTS AND MAIN RESULTS

Of 7,133 patients, 130 patients (1.8%) fulfilled criteria for acute lung injury (American European Consensus conference) or acute respiratory distress syndrome (Berlin definition). Median time for diagnosis was 2 days (interquartile range, 0-3 d). Main risk factors were pneumonia (35.3%) and nonpulmonary sepsis (31.5%). Mean age was 44.2 ± 15.9 years, and 61.5% were men. Mean Acute Physiology and Chronic Health Evaluation II score was 20.7 ± 7.9. Mean PaO2/FIO2 was 206 ± 61.5, significantly lower in nonsurvivors on day 7 (p = 0.003). Mean mechanical ventilation time was 21 ± 15 days. Length of ICU stay was 26.4 ± 18.7 days. Twenty-eight-day mortality was 38.5% (95% CI, 30.1-46.8); hospital mortality was 49.2% (95% CI, 40.6-57.8). Predictive 28-day mortality area under the receiver operating characteristic curve for American European Consensus conference definition was 0.5625 (95% CI, 0.4783-0.6467) and for the Berlin definition 0.5664 (95% CI, 0.4759-0.6568; p = 0.9510).

CONCLUSIONS

In our population, prevalence of acute lung injury was low, most cases were diagnosed 2 days after ICU admission, and Berlin definition was not different from American European Consensus conference definition in predicting mortality. There are still several problems with the global epidemiology, definition, and mortality predictive indices that should be added to the classification of this still lethal syndrome to improve its predictive mortality power in the future.

p-Synephrine suppresses lipopolysaccharide-induced acute lung injury by inhibition of the NF-κB signaling pathway

OBJECTIVE

We investigated whether p-synephrine exerts potent anti-inflammatory effects against acute lung injury (ALI) induced by lipopolysaccharide (LPS) in vivo, and we further investigated the inhibitory mechanism of p-synephrine in LPS-induced ALI.

METHODS

Lipopolysaccharide (0.5 mg/kg) was instilled intranasally in phosphate-buffered saline to induce acute lung injury, and 6, 24, and 48 h after LPS was given, bronchoalveolar lavage fluid was obtained to measure pro-inflammatory mediator. We also evaluated the effects of p-synephrine on LPS-induced the severity of pulmonary injury. The phosphorylation of nuclear factor-κB (NF-κB) p65 protein was analyzed by Western blotting.

RESULTS

Our data showed that p-synephrine significantly reduced the amount of inflammatory cells, the lung wet-to-dry weight (W/D) ratio, reactive oxygen species, myeloperoxidase activity and enhanced superoxide dismutase (SOD) in mice with LPS-induced ALI. Tumor necrosis factor α and interleukin (IL)-6 concentrations decreased significantly while the concentration of IL-10 was significantly increased after p-synephrine pretreatment. In addition, p-synephrine suppressed not only the phosphorylation of NF-κB but also the degradation of its inhibitor (IκBα).

CONCLUSIONS

These results suggested that the inhibition of NF-κB activation and the regulation of SOD are involved in the mechanism of p-synephrine's protection against ALI.

Biomarkers of lung epithelial injury and inflammation distinguish severe sepsis patients with acute respiratory distress syndrome

Introduction

Despite recent modifications, the clinical definition of the acute respiratory distress syndrome (ARDS) remains non-specific, leading to under-diagnosis and under-treatment. This study was designed to test the hypothesis that a biomarker panel would be useful for biologic confirmation of the clinical diagnosis of ARDS in patients at risk of developing ARDS due to severe sepsis.

Methods

This was a retrospective case control study of 100 patients with severe sepsis and no evidence of ARDS compared to 100 patients with severe sepsis and evidence of ARDS on at least two of their first four ICU days. A panel that included 11 biomarkers of inflammation, fibroblast activation, proteolytic injury, endothelial injury, and lung epithelial injury was measured in plasma from the morning of ICU day two. A backward elimination model building strategy on 1,000 bootstrapped data was used to select the best performing biomarkers for further consideration in a logistic regression model for diagnosis of ARDS.

Results

Using the five best-performing biomarkers (surfactant protein-D (SP-D), receptor for advanced glycation end-products (RAGE), interleukin-8 (IL-8), club cell secretory protein (CC-16), and interleukin-6 (IL-6)) the area under the receiver operator characteristic curve (AUC) was 0.75 (95% CI: 0.7 to 0.84) for the diagnosis of ARDS. The AUC improved to 0.82 (95% CI: 0.77 to 0.90) for diagnosis of severe ARDS, defined as ARDS present on all four of the first four ICU days.

Conclusions

Abnormal levels of five plasma biomarkers including three biomarkers generated by lung epithelium (SP-D, RAGE, CC-16) provided excellent discrimination for diagnosis of ARDS in patients with severe sepsis. Altered levels of plasma biomarkers may be useful biologic confirmation of the diagnosis of ARDS in patients with sepsis, and also potentially for selecting patients for clinical trials that are designed to reduce lung epithelial injury.

Automated alerting and recommendations for the management of patients with preexisting hypoxia and potential acute lung injury: a pilot study

BACKGROUND

Acute lung injury (ALI) is associated with high mortality. Low tidal volume (Vt) ventilation has been shown to reduce mortality in ALI patients in the intensive care unit. Anesthesiologists do not routinely provide lung-protective ventilation strategies to patients with ALI in the operating room. The authors hypothesized that an alert, recommending lung-protective ventilation regarding patients with potential ALI, would result in lower Vt administration.

METHODS

The authors conducted a randomized controlled trial on anesthesia providers caring for patients with potential ALI. Patients with an average or last collected ratio of partial pressure of arterial oxygen to inspired fraction of oxygen less than 300 were randomized to providers being sent an alert with a recommended Vt of 6 cc/kg predicted body weight or conventional care. Primary outcomes were Vt/kg predicted body weight administered to patients. Secondary outcomes included ventilator parameters, length of postoperative ventilation, and death.

RESULTS

The primary outcome was a clinically significant reduction in mean Vt from 508-458 cc (P = 0.033), with a reduction in Vt when measured in cc/kg predicted body weight from 8 to 7.2 cc/kg predicted body weight (P = 0.040). There were no statistically significant changes in other outcomes or adverse events associated with either arm.

CONCLUSIONS

Automated alerts generated for patients at risk of having ALI resulted in a statistically significant reduction in Vt administered when compared with a control group. Further research is required to determine whether a reduction in Vt results in decreased mortality and/or postoperative duration of mechanical ventilation.

Acute respiratory distress syndrome: current concepts and future directions

Acute respiratory distress syndrome is one of the leading causes of death in critically ill patients. Recent advances in supportive care have led to a moderate improvement in mortality. In particular, a much lower mortality rate than expected was evident in the severest category of patients (requiring extracorporeal membrane oxygenation) in Australia during the recent H1N1 pandemic. Though improvements in supportive care may have provided some benefit, there remains an absence of effective biological agents that are necessary to achieve further incremental reduction in mortality. This article will review the evidence available for current treatment strategies and discuss future research directions that may eventually improve outcomes in this important global disease.