ARDS Neutrophils Have a Distinct Phenotype and are Resistant to Phosphoinositide 3-kinase Inhibition (original) (raw)
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Scientific Reports
Acute respiratory distress syndrome (ARDS) is associated with high mortality. We sought to identify biological pathways in ARDS that differentiate survivors from non-survivors. We studied bronchoalveolar lavage fluid (BALF) from 36 patients with ARDS (20 survivors, 16 non-survivors). Each sample, obtained within seven days of ARDS onset, was depleted of high abundance proteins and labeled for iTRAQ LC-MS/MS separately. Protein identification and relative quantification was performed employing a target-decoy strategy. A variance weighted t-test was used to identify differential expression. Ingenuity Pathway Analysis was used to determine the canonical pathways that differentiated survivors from non-survivors. We identified 1115 high confidence proteins in the BALF out of which 142 were differentially expressed between survivors and non-survivors. These proteins mapped to multiple pathways distinguishing survivors from non-survivors, including several implicated in lung injury and repair such as coagulation/thrombosis, acute phase response signaling and complement activation. We also identified proteins assigned to fibrosis and ones involved in detoxification of lipid peroxide-mediated oxidative stress to be different in survivors and non-survivors. These results support our previous findings demonstrating early differences in the BALF protein expression in ARDS survivors vs. non-survivors, including proteins that counter oxidative stress and canonical pathways associated with fibrosis. Acute respiratory distress syndrome (ARDS) occurs as a response to infectious or inflammatory triggers and is characterized by acute tachypnea, refractory hypoxia, and loss of lung compliance 1. Although a variety of conditions are triggers for ARDS, common risk factors include pneumonia (59%), extrapulmonary sepsis (16%), and aspiration (14.2%) 2. Despite widespread adoption of lung protective ventilation 3 , early use of muscle relaxants 4 , extracorporeal membrane oxygenation 5 and prone ventilation 6 , case fatality rates remain at 30-40% 2, 7-10. Regardless of the cause of ARDS, there is an unmet need to develop tools to reliably assess the mortality risk of patients early in ARDS evolution in order to design interventions to improve survival rates. The current definition of ARDS is based on physiological derangement 11 and does not identify causal mechanisms. However, there is heterogeneity in disease susceptibility 12-16 and manifestations. Only 50% of cases classified as ARDS have diffuse alveolar damage on biopsy 17. Other lung-specific responses differ with respect to the degree of hypoxia 2 , ventilator driving pressure 18 , lung stiffness 17 , and collagen deposition 19-21. A greater understanding of the differences in the
Advances in Understanding of the Pathogenesis of Acute Respiratory Distress Syndrome
Respiration, 2015
The clinical syndrome of acute lung injury (ALI) occurs as a result of an initial acute systemic inflammatory response. This can be consequent to a plethora of insults, either direct to the lung or indirect. The insult results in increased epithelial permeability, leading to alveolar flooding with a proteinrich oedema fluid. The resulting loss of gas exchange leads to acute respiratory failure and typically catastrophic illness, termed acute respiratory distress syndrome (ARDS), requiring ventilatory and critical care support. There remains a significant disease burden, with some estimates showing 200,000 cases each year in the USA with a mortality approaching 50%. In addition, there is a significant burden of morbidity in survivors. There are currently no disease-modifying therapies available, and the most effective advances in caring for these patients have been in changes to ventilator strategy as a result of the ARDS network studies nearly 15 years ago. Here, we will give an overview of more recent advances in the understanding of the cellular biology of ALI and highlight areas that may prove fertile for future diseasemodifying therapies.
PLoS ONE, 2011
Acute respiratory distress syndrome (ARDS) is a poorly understood condition with greater than 30% mortality. Massive recruitment of neutrophils to the lung occurs in the initial stages of the ARDS. Significant variability in the severity and duration of ARDS-associated pulmonary inflammation could be linked to heterogeneity in the inflammatory capacity of neutrophils. Interferon-stimulated genes (ISGs) are a broad gene family induced by Type I interferons. While ISGs are central to anti-viral immunity, the potential exists for these genes to evoke extensive modification in cellular response in other clinical settings. In this prospective study, we sought to determine if ISG expression in circulating neutrophils from ARDS patients is associated with changes in neutrophil function. Circulating neutrophil RNA was isolated, and hierarchical clustering ranked patients' expression of three ISGs. Neutrophil response to pathogenic bacteria was compared between normal and high ISG-expressing neutrophils. High neutrophil ISG expression was found in 25 of 95 (26%) of ARDS patients and was associated with reduced migration toward interleukin-8, and altered responses to Staphylococcus aureus, but not Pseudomonas aeruginosa, which included decreased p38 MAP kinase phosphorylation, superoxide anion release, interleukin-8 release, and a shift from necrotic to apoptotic cell death. These alterations in response were reflected in a decreased capacity to kill S. aureus, but not P. aeruginosa. Therefore, the ISG expression signature is associated with an altered circulating neutrophil response phenotype in ARDS that may predispose a large subgroup of patients to increased risk of specific bacterial infections.
Acute Respiratory Distress Syndrome: 30 Years Later?
Canadian Respiratory Journal, 1999
Acute respiratory distress syndrome (ARDS) was first described about 30 years ago. Modern definitions and statements have recently been proposed to describe ARDS accurately, but none is perfect. Diffuse alveolar damage is the basic pathological pattern most commonly observed in ARDS, and the term includes permeability edema. The alveolar epithelium of the alveolar-capillary barrier is clearly a key component requiring repair, given its multipotent functional activity. Lung inflammation and neutrophil accumulation are essential markers of disease in ARDS, and a wide variety of pro- and anti-inflammatory cytokines have been described in the alveolar fluid and blood of patients. These molecules still have to prove their value as diagnostic or prognostic biomarkers of ARDS.Supportive therapy in ARDS improved in the past decade; mechanical ventilation with lung protective strategies and patient positioning are gaining interest, but the indications for corticosteroids for ARDS are still d...
Journal of Critical Care, 2013
Purpose: Recent studies suggest a role for distal airway injury in acute respiratory distress syndrome (ARDS). The epithelium lining the small airways secretes a large number of molecules such as surfactant components and inflammatory mediators. There is little information on how these small airway secretory functions are altered in ARDS. Materials and Methods: We studied the lungs of 31 patients with ARDS (PaO 2 /fraction of inspired oxygen ≤200, 45 ± 14 years, 16 men) and 11 controls (52 ± 16 years, 7 men) submitted to autopsy and quantified the expression of interleukin (IL) 6, IL-8, surfactant proteins (SP) A and SP-B in the epithelium of small airways using immunohistochemistry and image analysis. In addition, an index of airway epithelial apoptosis was determined by the terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphatase nick-end labeling assay, caspase 3, and Fas/Fas ligand expression. The density of inflammatory cells expressing IL-6 and IL-8 within the small airway walls was also quantified. Results: Acute respiratory distress syndrome airways showed an increase in the epithelial expression of IL-8 (P = .006) and an increased density of inflammatory cells expressing IL-6 (P = .004) and IL-8 (P b .001) compared with controls. There were no differences in SP-A and SP-B epithelium expression or in epithelial apoptosis index between ARDS and controls. Conclusion: Distal airways are involved in ARDS lung inflammation and show a high expression of proinflammatory interleukins in both airway epithelial and inflammatory cells. Apoptosis may not be a major mechanism of airway epithelial cell death in ARDS.
American Journal of Respiratory and Critical Care Medicine, 1996
It was recently demonstrated that nitric oxide (NO) inhalation improves arterial oxygenation in patients with the adult respiratory distress syndrome (ARDS). However, the potential adverse reaction of NO on inflammatory cells and mediators in the lung has not yet been investigated. In this study, we evaluated the impact of NO inhalation on lung polymorphonuclear neutrophil (PMN) activation and proinflammatory cytokine release, both of which are involved in the pathophysiology of ARDS. Two groups of patients with ARDS of similar etiologies were compared; one received NO (n =9) and the other did not (n = 5). After 4 d of NO inhalation (18 ppm), PMN from bronchoalveolar lavage (BAL) showed a reduction in both spontaneous H202 production (p < 0.05) and 132 integrin CDll b/ CD18 expression (p < 0.05). Moreover, the high levels of IL-8 and IL-6 decreased in BAL fluid supernatants after NO inhalation (p < 0.05). In the NO-untreated group of patients with ARDS, neither PMN activation nor levels of IL-8 and IL-6 in BAL fluid changed significantly on Day 4. These results suggest that NO inhalation might reduce lung inflammation in ARDS, as reflected by PMN activation status and IL-8/IL-6 release. Chollet-Martln 5, Gatecel C, Kermarrec N, Gougerot-Pocldalo M-A, Payen DM. Alveolar neutrophil funrtions and cytokine levels in patients with the adult respiratory distress syndrome during nitric oxide inhalation.
Respiratory research, 2002
The predictive role of many cytokines and adhesion molecules has not been studied systematically in acute respiratory distress syndrome (ARDS). We measured prospectively tumour necrosis factor alpha (TNF-alpha), interleukin (IL)-1, soluble vascular adhesion molecule-1 (VCAM-1) and soluble intercellular adhesion molecule-1 (ICAM-1) in serum and bronchoalveolar lavage fluid (BALF) within 2 hours following admission, in 65 patients. The patients were divided into: those fulfilling the criteria for ARDS (n = 23, group A), those who were pre-ARDS and who developed ARDS within 24 hours (n = 14, group B), and those on pre-ARDS but who never developed ARDS (n = 28, group C). All the measured molecules were only found at higher levels in the serum of patients that died either with or without ARDS (P < 0.05 - P < 0.0001). Patients at risk exhibited a good negative predictive value (NPV) of the measured molecules for ARDS development both in their serum (89 to 95%) and BALF (86 to 92%) l...