Secretory Phospholipase A2-IIA Protein and mRNA Pools in Extracellular Vesicles of Bronchoalveolar Lavage Fluid from Patients with Early Acute Respiratory Distress Syndrome: A New Perception in the Dissemination of Inflammation?

Secretory phospholipase-IIA A2 (sPLA2-IIA) is expressed in a variety of cell types under inflammatory conditions. Its presence in the bronchoalveolar lavage (BAL) fluid of patients with acute respiratory distress syndrome (ARDS) is associated with the severity of the injury. Exosomal type extracellular vesicles, (EVs), are recognized to perform intercellular communication. They may alter the immune status of recipient target cells through cargo shuttling. In this work, we characterized the exosomal type EVs isolated from BAL fluid of patients with early and late ARDS as compared to control/non-ARDS patients, through morphological (confocal and electron microscopy) and biochemical (dynamic light scattering, qRT-PCR, immunoblotting) approaches. We provide evidence for the presence of an sPLA2-IIA-carrying EV pool that coprecipitates with exosomes in the BAL fluid of patients with ARDS. PLA2G2A mRNA was present in all the samples, although more prominently expressed in early ARDS. However, the protein was found only in EVs from early phase ARDS. Under both forms, sPLA2-IIA might be involved in inflammatory responses of recipient lung cells during ARDS. The perception of the association of sPLA2-IIA to the early diagnosis of ARDS or even with a mechanism of development and propagation of lung inflammation can help in the adoption of appropriate and innovative therapeutic strategies.

Elevated CA-125 in IgG4 mesenteritis: a red herring or a disease biomarker? Case report and literature review.

Mesenteric panniculitis (MP) is a rare chronic disease characterized by inflammation and subsequently fibrosis of adipose tissue of the omentum. Only recently it has been associated with IgG4-related disease. Cancer antigen 125 (CA-125) is a high-molecular mass glycoprotein, traditionally associated with ovarian cancer, although it can be elevated in other conditions. Herein we describe a case of a 56-year-old man with IgG4 related mesenteric panniculitis associated with very high levels of CA-125 at the onset of disease. The CA-125 levels corresponded to clinical disease activity and improved with steroid therapy and rituximab. A literature review was performed concerning possible association of MP, IgG4-related disease and CA-125. The review of literature suggests that high levels of CA-125 can be raised in non-malignant, inflammatory conditions including IgG4-related mesenteritis and can improve with treatment.

The contribution of left heart disease in COPD patients with pulmonary hypertension.

BACKGROUND: Pulmonary hypertension (PH), regardless of its etiology, is associated with an impaired outcome in patients with chronic obstructive pulmonary disease (COPD). The aim of our study was to determine the incidence, cause, and effect of PH as detected by echocardiography in COPD patients. METHODS: Patients with confirmed COPD of any stage were evaluated by echocardiography for the likelihood of PH according to the proposed criteria. Patients with possible/likely to have PH underwent right heart catheterization, upon agreement, to confirm the presence, severity, and cause of PH. RESULTS: Of 91 patients, 39 were in stable condition (group A) and 52 with COPD exacerbation (group B). Group B patients presented with PH and left ventricular diastolic dysfunction more often than group A patients. One of two fulfilled the criteria for possible/likely PH. The incidence of likely/possible PH was significantly higher in group B. Nineteen group B patients with likely/possible PH underwent RHC, and PH was confirmed in 15 cases and in 73.3% was associated with left heart disease. The presence of possible/likely PH was associated with a statistically significant increase in mortality compared to those with unlikely PH. CONCLUSIONS: The use of echocardiographic criteria for the presence of PH is adequate for the screening of COPD patients. Patients with acute exacerbation of COPD and possible/likely PH demonstrate worse mortality compared to patients unlikely to have PH.

The impact of healthcare professionals' personality and religious beliefs on the decisions to forego life sustaining treatments: an observational, multicentre, cross-sectional study in Greek intensive care units.

OBJECTIVES: To assess the opinion of intensive care unit (ICU) personnel and the impact of their personality and religious beliefs on decisions to forego life-sustaining treatments (DFLSTs). SETTING: Cross-sectional, observational, national study in 18 multidisciplinary Greek ICUs, with >6 beds, between June and December 2015. PARTICIPANTS: 149 doctors and 320 nurses who voluntarily and anonymously answered the End-of-Life (EoL) attitudes, Personality (EPQ) and Religion (SpREUK) questionnaires. Multivariate analysis was used to detect the impact of personality and religious beliefs on the DFLSTs. RESULTS: The participation rate was 65.7%. Significant differences in DFLSTs between doctors and nurses were identified. 71.4% of doctors and 59.8% of nurses stated that the family was not properly informed about DFLST and the main reason was the family's inability to understand medical details. 51% of doctors expressed fear of litigation and 47% of them declared that this concern influenced the information given to family and nursing staff. 7.5% of the nurses considered DFLSTs dangerous, criminal or illegal. Multivariate logistic regression identified that to be a nurse and to have a high neuroticism score were independent predictors for preferring the term 'passive euthanasia' over 'futile care' (OR 4.41, 95% CI 2.21 to 8.82, p<0.001, and OR 1.59, 95% CI 1.03 to 2.72, p<0.05, respectively). Furthermore, to be a nurse and to have a high-trust religious profile were related to unwillingness to withdraw mechanical ventilation. Fear of litigation and non-disclosure of the information to the family in case of DFLST were associated with a psychoticism personality trait (OR 2.45, 95% CI 1.25 to 4.80, p<0.05). CONCLUSION: We demonstrate that fear of litigation is a major barrier to properly informing a patient's relatives and nursing staff. Furthermore, aspects of personality and religious beliefs influence the attitudes of ICU personnel when making decisions to forego life-sustaining treatments.

Burnout and job satisfaction of intensive care personnel and the relationship with personality and religious traits: An observational, multicenter, cross-sectional study.

OBJECTIVES: To investigate if burnout in the Intensive Care Unit (ICU) is influenced by aspects of personality, religiosity and job satisfaction. RESEARCH METHODOLOGY: Cross-sectional study, designed to assess burnout in the ICU and to investigate possible determinants. Three different questionnaires were used: the Malach Burnout Inventory, the Eysenck Personality Questionnaire and the Spiritual/Religious Attitudes Questionnaire. Predicting factors for high burnout were identified by multivariate logistic regression analysis. SETTING/PARTICIPANTS: This national study was addressed to physicians and nurses working full-time in 18 Greek ICU departments from June to December 2015. RESULTS: The participation rate was 67.9% (n=149) and 65% (n=320) for ICU physicians and nurses, respectively). High job satisfaction was recorded in both doctors (80.8%) and nurses (63.4%). Burnout was observed in 32.8% of the study participants, higher in nurses compared to doctors (p<0.001). Multivariate analysis revealed that neuroticism was a positive and extraversion a negative predictor of exhaustion (OR 5.1, 95%CI 2.7-9.7, p<0.001 and OR 0.49, 95%CI 0.28-0.87, p=0.014, respectively). Moreover, three other factors were identified: Job satisfaction (OR 0.26, 95%CI 0.14-0.48, p<0.001), satisfaction with current End-of-Life care (OR 0.41, 95%CI 0.23-0.76, p=0.005) and isolation feelings after decisions to forego life sustaining treatments (OR 3.48, 95%CI 1.25-9.65, p=0.017). CONCLUSIONS: Personality traits, job satisfaction and the way End-of-Life care is practiced influence burnout in the ICU.

Why there is a need to discuss pulmonary hypertension other than pulmonary arterial hypertension?

Pulmonary hypertension (PH) is a condition characterized by the elevation of the mean pulmonary artery pressure above 25 mmHg and the pulmonary vascular resistance above 3 wood units. Pulmonary arterial hypertension (PAH) is an uncommon condition with severe morbidity and mortality, needing early recognition and appropriate and specific treatment. PH is frequently associated with hypoxemia, mainly chronic obstructive pulmonary disease and DPLD and/or left heart diseases (LHD), mainly heart failure with reduced or preserved ejection fraction. Although in the majority of patients with PH the cause is not PAH, a significant number of published studies are still in regard to group I PH, leading to a logical assumption that PH due to other causes is not such an important issue. So, is there a reason to discuss PH other than PAH? Chronic lung diseases, mainly chronic obstructive lung disease and DPLD, are associated with a high incidence of PH which is linked to exercise limitations and a worse prognosis. Although pathophysiological studies suggest that specific PAH therapy may benefit such patients, the results presented from small studies in regard to the safety and effectiveness of the specific PAH therapy are discouraging. PH is a common complication of left heart disease and is related to disease severity, especially in patients with reduced ejection fraction. There are two types of PH related to LHD based on diastolic pressure difference (DPD, defined as diastolic pulmonary artery pressure - mean PAWP): Isolated post-capillary PH, defined as PAWP > 15 mmHg and DPD < 7 mmHg, and combined post-capillary PH and pre-capillary PH, defined as PAWP > 15 mmHg and DPD ≥ 7 mmHg. The potential use of PAH therapies in patients with PH related to left heart disease is based on a logical pathobiological rationale. In patients with heart failure, endothelial dysfunction has been proposed as a cause of PH and hence as a target for treatment, supported by the presence of increased endothelin-1 activity and impaired nitric oxide-dependent vasodilation. Unfortunately, so far, there is no evidence supporting the use of specific PAH therapies in patients with PH related to left heart disease. In conclusion, the presence of PH in patients with conditions other than PAH contributes to the severity of the disease, affecting the outcome and quality of life. The disappointing results regarding the effectiveness of specific PAH therapies in patients with chronic lung diseases and LHD underline the need for seeking new underlying mechanisms and thus novel therapies targeting PH due to left heart disease and/or lung diseases.

Immobilization of Lipid Substrates: Application on Phospholipase A2 Determination.

The purpose of the study was to assess a fluorimetric assay for the determination of total phospholipase A(2) (PLA(2)) activity in biological samples introducing the innovation of immobilized substrates on crosslinked polymeric membranes. The immobilized C(12)-NBD-PtdCho, a fluorescent analogue of phosphatidylcholine, exhibited excellent stability for 3 months at 4 °C and was not desorbed in the aqueous reaction mixture during analysis. The limit of detection was 0.5 pmol FA (0.2 pg) and the linear part of the response curve extended from 1 up to 190 nmol FA/h/mL sample. The intra- and inter-day relative standard deviations (%RSD), were ≤6 and ≤9 %, respectively. Statistical comparison with other fluorescent methods showed excellent correlation and agreement. Semiempirical calculations showed a fair amount of electrostatic interaction between the NBD-labeled substrate and the crosslinked polyvinyl alcohol with the styryl pyridinium residues (PVA-SbQ) material, from the plane of which, the sn-2 acyl chain of the phospholipid stands out and is accessible by PLA(2). Atomic Force Microscopy revealed morphological alterations of the immobilized substrate after the reaction with PLA(2). Mass spectrometry showed that only C(12)-NBD-FA, the PLA(2 )hydrolysis product, was detected in the reaction mixture, indicating that PLA(2) recognizes PVA-SbQ/C(12)-NBD-PtdCho as a surface to perform catalysis.

Effect of azithromycin on the LPS-induced production and secretion of phospholipase A2 in lung cells.

Azithromycin is a member of macrolides, utilized in the treatment of infections. Independently, these antibiotics also possess anti-inflammatory and immunomodulatory properties. Phospholipase A2 isotypes, which are implicated in the pathophysiology of inflammatory lung disorders, are produced by alveolar macrophages and other lung cells during inflammatory response and can promote lung injury by destructing lung surfactant. The aim of the study was to investigate whether in lung cells azithromycin can inhibit secretory and cytosolic phospholipases A2, (sPLA2) and (cPLA2), respectively, which are induced by an inflammatory trigger. In this respect, we studied the lipopolysaccharide (LPS)-mediated production or secretion of sPLA2 and cPLA2 from A549 cells, a cancer bronchial epithelial cell line, and alveolar macrophages, isolated from bronchoalveolar lavage fluid of ARDS and control patients without cardiopulmonary disease or sepsis. Pre-treatment of cells with azithromycin caused a dose-dependent decrease in the LPS-induced sPLA2-IIA levels in A549 cells. This inhibition was rather due to reduced PLA2G2A mRNA expression and secretion of sPLA2-IIA protein levels, as observed by western blotting and indirect immunofluorescence by confocal microscopy, respectively, than to the inhibition of the enzymic activity per se. On the contrary, azithromycin had no effect on the LPS-induced production or secretion of sPLA2-IIA from alveolar macrophages. The levels of LPS-induced c-PLA2 were not significantly affected by azithromycin in either cell type. We conclude that azithromycin exerts anti-inflammatory properties on lung epithelial cells through the inhibition of both the expression and secretion of LPS-induced sPLA2-IIA, while it does not affect alveolar macrophages.

Targeting occult heart failure in intensive care unit patients with acute chronic obstructive pulmonary disease exacerbation: effect on outcome and quality of life.

PURPOSE: To estimate the prevalence of previously undiagnosed heart failure in mechanically ventilated patients with severe exacerbation of chronic obstructive pulmonary disease (COPD) and to evaluate the impact of specific heart failure treatment on patients' outcome. MATERIALS AND METHODS: In this prospective study, we included 107 consecutive patients with COPD without known history of cardiac disease who were admitted to the intensive care unit (ICU) because of hypercapnic respiratory failure leading to mechanical ventilation. RESULTS: Patients were divided into 4 groups according to the echocardiographic findings: patients with isolated right or left ventricular failure, biventricular failure, and normal heart function. Three of 4 patients demonstrated findings of heart failure. In 41%, the presence of previously unrecognized left ventricular dysfunction was revealed. Patients with isolated left ventricular dysfunction experienced less days on mechanical ventilation, less intensive care unit days, improved quality of life, and decreased in-hospital and 6-month mortality compared with patients with normal heart. CONCLUSIONS: In mechanically ventilated patients with severe exacerbation of COPD, unrecognized left or right ventricular failure is common. Among patients with isolated left ventricular failure, the early detection and appropriate treatment improves long-term quality of life and may decrease the short- and 6-month morbidity and mortality.

Dipalmitoyl-phosphatidylcholine biosynthesis is induced by non-injurious mechanical stretch in a model of alveolar type II cells.

Dipalmitoylphosphatidylcholine, (DP-PtdCho), the major phospholipid component of lung surfactant is biosynthesized via a de novo pathway, the last step of which is catalyzed by CDP-choline:cholinephosphotransferase (CPT) and two remodeling steps: a deacylation and a reacylation one, catalyzed by an acidic, Ca²âº-independent phospholipase A2 (aiPLA2) and a lyso-phosphatidylcholine acyltransferase (LPCAT), respectively. The aim of our study was to investigate whether a low magnitude, non-injurious static mode of mechanical stretch can induce phosphatidylcholine (PtdCho) biosynthesis and its remodeling to DP-PtdCho in the A549 cell-line, a model of alveolar type II cells. The deformation of A549 cells did not cause any release of lactate dehydrogenase, or phospholipids into the cell culture supernatants. An increase in PtdCho levels was observed after 1 h of static stretching, especially among the DP-PtdCho molecular species, as indicated by targeted lipidomics approach and site-directed fatty acyl-chain analysis. Moreover, although sphingomyelin (CerPCho) levels were unaffected, the DP-PtdCho/CerPCho ratio increased. Induction was observed in CPT, LPCAT and aiPLA2 enzymatic activities and gene expression. Finally, incubation of the cells with MJ33 suppressed aiPLA2 activity and DP-PtdCho production. Our data suggest that mild static mechanical stretch can promote the biosynthesis of PtdCho and its remodeling to DP-PtdCho in lung epithelial cells. Thus, low magnitude stretch could contribute to protective mechanisms rather than to injurious ones.

Attributable mortality of ventilator-associated pneumonia: a meta-analysis of individual patient data from randomised prevention studies.

BACKGROUND: Estimating attributable mortality of ventilator-associated pneumonia has been hampered by confounding factors, small sample sizes, and the difficulty of doing relevant subgroup analyses. We estimated the attributable mortality using the individual original patient data of published randomised trials of ventilator-associated pneumonia prevention. METHODS: We identified relevant studies through systematic review. We analysed individual patient data in a one-stage meta-analytical approach (in which we defined attributable mortality as the ratio between the relative risk reductions [RRR] of mortality and ventilator-associated pneumonia) and in competing risk analyses. Predefined subgroups included surgical, trauma, and medical patients, and patients with different categories of severity of illness scores. FINDINGS: Individual patient data were available for 6284 patients from 24 trials. The overall attributable mortality was 13%, with higher mortality rates in surgical patients and patients with mid-range severity scores at admission (ie, acute physiology and chronic health evaluation score [APACHE] 20-29 and simplified acute physiology score [SAPS 2] 35-58). Attributable mortality was close to zero in trauma, medical patients, and patients with low or high severity of illness scores. Competing risk analyses could be done for 5162 patients from 19 studies, and the overall daily hazard for intensive care unit (ICU) mortality after ventilator-associated pneumonia was 1·13 (95% CI 0·98-1·31). The overall daily risk of discharge after ventilator-associated pneumonia was 0·74 (0·68-0·80), leading to an overall cumulative risk for dying in the ICU of 2·20 (1·91-2·54). Highest cumulative risks for dying from ventilator-associated pneumonia were noted for surgical patients (2·97, 95% CI 2·24-3·94) and patients with mid-range severity scores at admission (ie, cumulative risks of 2·49 [1·81-3·44] for patients with APACHE scores of 20-29 and 2·72 [1·95-3·78] for those with SAPS 2 scores of 35-58). INTERPRETATION: The overall attributable mortality of ventilator-associated pneumonia is 13%, with higher rates for surgical patients and patients with a mid-range severity score at admission. Attributable mortality is mainly caused by prolonged exposure to the risk of dying due to increased length of ICU stay. FUNDING: None.

Inhaled NO and sildenafil combination in cardiac surgery patients with out-of-proportion pulmonary hypertension: acute effects on postoperative gas exchange and hemodynamics.

BACKGROUND: The goal of this study was to examine the effects of coadministration of sildenafil and inhaled nitric oxide (iNO) in patients with out-of-proportion pulmonary hypertension who underwent cardiac valve replacement surgery. METHODS AND RESULTS: Twenty consecutive cardiac surgery patients with out-of-proportion pulmonary hypertension were randomly assigned postoperatively into 2 groups: group A received 10 ppm of iNO followed by sildenafil (100 mg) orally 30 minutes later, and group B initially received sildenafil (100 mg) orally followed by 10 ppm of iNO 60 minutes later. Hemodynamic and gas exchange data were obtained at baseline, after administration of either iNO or sildenafil alone, and at 90 minutes from baseline. In group A, iNO resulted in a significant reduction in mean pulmonary artery pressure (MPAP) and pulmonary vascular resistance index (PVRI) (by 9.6% and 20.8%, respectively). In group B, sildenafil administration also resulted in a significant decrease in mean arterial pressure, MPAP, pulmonary artery occlusive pressure, PVRI, and systemic vascular resistance index but also in the PaO(2)/inspired fraction of oxygen ratio (by 18.7%, 22.0%, 15.7%, 31.6%, 21.3%, and 14%, respectively). In both groups, the coadministration of the 2 drugs resulted in a significant further reduction of mean arterial pressure, MPAP, pulmonary artery occlusive pressure, systemic vascular resistance index, and PVRI, whereas cardiac index and mixed venous oxygen saturation remained unchanged. The hypoxemia after sildenafil administration in group B improved after the coadministration of iNO, and thus PaO(2)/inspired fraction of oxygen returned to values near baseline. CONCLUSION: In this study, the postoperative coadministration of iNO and oral sildenafil in patients with out-of-proportion pulmonary hypertension undergoing cardiac surgery is safe and results in an additive favorable effect on pulmonary arterial pressure and pulmonary vascular resistance, without systemic hypotension and ventilation/perfusion mismatch.

Propofol prevents lung injury following intestinal ischemia-reperfusion.

BACKGROUND: The antioxidant properties of propofol have been shown to improve ischemia/reperfusion injury. We investigated whether anesthesia with propofol can ameliorate remote lung injury induced by intestinal ischemia-reperfusion (IIR). MATERIALS AND METHODS: Thirty male Wistar rats were randomly allocated in three groups (n = 10 each): animals in group Sham were anesthetized with ketamine and xylazine and then laparotomy and sham IIR followed. Animals in group IIR received ketamine and xylazine and were then subjected to clamping of the superior mesenteric artery for 45 min and reperfusion for 4 h. Group IIR+P received anesthesia with propofol and then IIR was induced, as in group IIR. Blood samples for blood gases and malondialdehyde measurements were drawn at the end of reperfusion. Bronchoalveolar lavage fluid (BALF) was obtained to measure cell counts, total protein, and phospholipids levels. RESULTS: Induction of IIR resulted in deteriorated oxygenation, acidemia, and inflammatory cells sequestration, along with increased BALF protein content and increased proportions of small surfactant aggregates. Anesthesia with propofol alleviated intestinal injury and efficiently prevented lipid oxidation. In group IIR+P inflammatory cell infiltration and pulmonary histologic changes were significantly limited. The increase in BALF total protein and the changes in surfactant aggregates were prevented, leading to normal systemic oxygenation. CONCLUSION: Using propofol to induce and maintain anesthesia efficiently prevented IIR-induced lung injury. Systemic antioxidant protection, improvement of intestinal injury, inhibition of the inflammatory response, and preservation of the alveolar-capillary permeability seem to be crucial mediating mechanisms for this simple and clinically relevant intervention.

Mild stretch activates cPLA2 in alveolar type II epithelial cells independently through the MEK/ERK and PI3K pathways.

Alveolar epithelial type II cells (AT II) in which lung surfactant synthesis and secretion take place, are subjected to low magnitude stretch during normal breathing. The aim of the study was to explore the effect of mild stretch on phospholipase A(2) (PLA(2)) activation, an enzyme known to be involved in surfactant secretion. In A549 cells (a model of AT II cells), we showed, using a fluorometric assay, that stretch triggers an increase of total PLA(2) activity. Western blot experiments revealed that the cytosolic isoform cPLA(2) is rapidly phosphorylated under stretch, in addition to a modest increase in cPLA(2) mRNA levels. Treatment of A549 cells with selective inhibitors of the MEK/ERK pathway significantly attenuated the stretch-induced cPLA(2) phosphorylation. A strong interaction of cPLA(2) and pERK enzymes was demonstrated by immunoprecipitation. We also found that inhibition of PI3K pathway attenuated cPLA(2) activation after stretch, without affecting pERK levels. Our results suggest that low magnitude stretch can induce cPLA(2) phosphorylation through the MEK/ERK and PI3K-Akt pathways, independently.

Early changes of procalcitonin may advise about prognosis and appropriateness of antimicrobial therapy in sepsis.

PURPOSE: The objective of this study is to define if early changes of procalcitonin (PCT) may inform about prognosis and appropriateness of administered therapy in sepsis. METHODS: A prospective multicenter observational study was conducted in 289 patients. Blood samples were drawn on day 1, that is, within less than 24 hours from advent of signs of sepsis, and on days 3, 7, and 10. Procalcitonin was estimated in serum by the ultrasensitive Kryptor assay (BRAHMS GmbH, Hennigsdorf, Germany). Patients were divided into the following 2 groups according to the type of change of PCT: group 1, where PCT on day 3 was decreased by more than 30% or was below 0.25 ng/mL, and group 2, where PCT on day 3 was either increased above 0.25 ng/mL or decreased less than 30%. RESULTS: Death occurred in 12.3% of patients of group 1 and in 29.9% of those of group 2 (P < .0001). Odds ratio for death of patients of group 1 was 0.328. Odds ratio for the administration of inappropriate antimicrobials of patients of group 2 was 2.519 (P = .003). CONCLUSIONS: Changes of serum PCT within the first 48 hours reflect the benefit or not of the administered antimicrobial therapy. Serial PCT measurements should be used in clinical practice to guide administration of appropriate antimicrobials.

Impaired phospholipases A2production by stimulated macrophages from patients with acute respiratory distress syndrome.

The aim of this study was to investigate whether early phase of acute respiratory distress syndrome (ARDS) is associated with changes in immune response, either systemic or localized to the lung. ARDS and control mechanically ventilated patients, as well as healthy volunteers were studied. Alveolar macrophages (AMΦ) and blood monocytes (BM) were treated ex vivo with lipopolysaccharide (LPS), interferon-γ (IFNγ), and surfactant. Phospholipase A2 (PLA2) activity and TLR4 expression were evaluated as markers of cell response. AMΦ from ARDS patients did not respond upon treatment with either LPS or IFN-γ by inducing PLA2 production. On the contrary, upon stimulation, in control patients the intracellular PLA2, (mainly cPLA2) levels were increased, but secretion of PLA2 (mainly sPLA2-IIA) was observed only after treatment with LPS. Surfactant suppressed PLA2 production in cells from both groups of patients. Increased relative changes of total PLA2 activity and an upregulation of TLR4 expression upon stimulation was observed in BM from primary ARDS, control patients and healthy volunteers. In BM from secondary ARDS patients, however, no PLA2 induction was observed, with a concomitant down-regulation of TLR4 expression. Cytosolic PLA2, its activated form, p-cPLA2, and sPLA2-IIA were the predominant PLA2 types within the cells, while extracellularly only sPLA2-IIA was identified. These results support the concept of down-regulated innate immunity in early ARDS that is compartmentalized in primary and systemic in secondary ARDS. PLA2 isoforms could serve as markers of the immunity status in ARDS. Finally, our data highlight the role of surfactant in controlling inflammation.

Intestinal preconditioning ameliorates ischemia-reperfusion induced acute lung injury in rats: an experimental study.

BACKGROUND: Phospholipases A(2) (PLA(2)) have been implicated in the pathogenesis of acute respiratory distress syndrome (ARDS) induced by intestinal ischemia-reperfusion (IIR). Intestinal ischemic preconditioning (IIP) has been shown to improve intestinal tolerance to subsequent sustained ischemia and limit the systemic inflammatory response. We tested the effect of IIP on the intestinal ischemia-reperfusion-induced ARDS, with particular focus on PLA(2). METHODS: Rats were randomized into three groups: (1) sham surgery group (sGroup), 45 min sham intestinal ischemia-4 h reperfusion, (2) IIR group (IIRGroup), 45 min intestinal ischemia-4 h reperfusion, (3) IIP group (ipGroup), three cycles of intestinal ischemia for 4 min and reperfusion for 10 min followed by 45 min intestinal ischemia-4 h reperfusion. At the end of each experiment, blood gases were obtained and bronchoalveolar lavage (BAL) followed. Biochemical (total protein, PLA(2), PAF-AcH) and cytological parameters of the BAL fluid were quantified. Plasma MDA was measured as an indicator of systemic oxidative stress. Comparisons between groups were made using one-way ANOVA followed by post hoc comparison with a Tukey test or Mann-Whitney test when appropriate. Differences were considered significant if P < 0.05. RESULTS: Alveolar-arterial O(2) gradient values and wet to dry lung ratio were significantly (P < 0.05) increased in the IIRGroup and this increase was prevented in the ipGroup. Following the same pattern, BAL total protein, PLA(2), and PAF-AcH were significantly lower in the ipGroup. Ischemic preconditioning significantly abolished neutrophil count in BAL fluid. Plasma MDA was significantly lower in the ipGroup. Despite a significant tissue polymorphonuclear reduction, no significant lung or intestinal histologic damage score changes were revealed. CONCLUSIONS: Intestinal preconditioning protects IIR-induced lung injury, partly by modulating the arachidonic acid cascade.