Inflammatory events after fibrin microembolization. Alterations in alveolar macrophage and neutrophil function

We performed bronchoalveolar lavage (BAL) 0.5 to 24 h after thrombin-induced pulmonary microembolization in spontaneously breathing sheep to examine the inflammatory events that occur after pulmonary intravascular coagulation. Neutrophil alveolitis was evident as early as 0.5 h after microembolization and was maximal at 4 h (4.9 +/- 1.5% neutrophils of total BAL cells at baseline versus 26.2 +/- 2.8% at 4 h post-thrombin). Neutrophils obtained both at baseline (isolated from peripheral blood) and at 0.5 to 24 h after thrombin (isolated from BAL) did not demonstrate significant basal production of superoxide anion (O2-) and produced similar amounts of O2- upon challenge with phorbol myristate acetate (PMA) 200 micrograms/ml. The basal O2- production by alveolar macrophages was also not increased. However, alveolar macrophages recovered after fibrin microembolization produced greater amounts of O2- (29.1 +/- 6.3 nm O2-/10(6) cells at 0.5 h) after challenge with PMA compared with alveolar macrophages recovered prior to embolization (10.6 +/- 1.6 nm O2-/10(6) cells baseline), suggesting that thrombin-induced microembolization primes alveolar macrophages and enhances their O2- generation. Neutrophil chemotactic activity was detected in BAL fluid at 0.5 h post-microembolization and reached a peak level at 2 h. Alveolar macrophages were a source of the chemotactic activity since conditioned medium obtained from 2-h post-thrombin macrophages induced neutrophil chemotaxis, whereas baseline cells did not. The addition of the thrombin to macrophages did not result in the generation of chemotactic activity from baseline macrophages, indicating that macrophages were activated during the process of intravascular coagulation rather than by thrombin per se. Post-thrombin BAL fluid also stimulated O2- generation from sheep neutrophils.(ABSTRACT TRUNCATED AT 250 WORDS)     

Increased levels of oxidized methionine residues in bronchoalveolar lavage fluid proteins from patients with idiopathic pulmonary fibrosis

Phagocytic cells are believed to play a crucial role in the development of inflammatory lung diseases. We assumed that the oxidation of methionine (met) to methionine sulfoxide [met(O)] by oxygen-derived free radicals released from phagocytes is one parameter to identify the oxidative mechanisms of lung injury. To test this hypothesis we determined the molar ratio of met(O)/met in the soluble protein fraction of bronchoalveolar lavage (BAL) fluids from healthy nonsmokers and from nonsmoking patients with idiopathic pulmonary fibrosis (IPF) or sarcoidosis. The met(O)/met ratio of the healthy nonsmoker group (n = 11) was 0.046 +/- 0.008 (mean +/- SEM). In contrast, the met(O)/met ratio of the nonsmoking IPF group (n = 11) was significantly increased to 0.223 +/- 0.053 (p less than 0.0002). The BAL fluids of this group showed strongly increased numbers of neutrophils but normal numbers of alveolar macrophages (AM). In the sarcoidosis group (n = 10) the met(O)/met ratio (0.048 +/- 0.010) was not significantly different from control values. A close relationship was found between the met(O)/met ratios and the relative as well as the absolute neutrophil counts (r = 0.86; p less than 0.0002; n = 22). In contrast, no significant correlation was found between the met(O)/met ratios and the absolute AM counts (r = 0.22; p = 0.32; n = 22). We conclude that mechanisms of oxidative lung injury in IPF can be characterized by oxidation of met and that this oxidation may be mediated by neutrophils.     

Hyperoxic exposure in humans. Effects of 50 percent oxygen on alveolar macrophage leukotriene B4 synthesis.

The pathogenesis of oxygen toxicity remains unknown but may involve leukocyte mediated injury. The effects of hyperoxia on several lower respiratory tract parameters were examined in bronchoalveolar lavage fluid of normal nonsmoking subjects who inhaled a fractional inspired oxygen concentration of 50 percent (mean exposure: 44 h). Evidence that 50 percent O2 produced oxidative stress in the lung included recovery of fluorescent products of lipid peroxidation and partial oxidation of alpha 1-antitrypsin in BAL fluid obtained after O2 exposure. To examine whether alveolar macrophage-derived leukotriene B4 may be generated in response to 50 percent O2, AM were isolated from O2-exposed subjects and compared with AM recovered from subjects breathing room air. Leukotriene B4 levels were elevated in supernatants from both unstimulated and arachidonic acid-stimulated AM obtained from hyperoxia-exposed subjects. In hyperoxia-exposed individuals, LTB4 levels were also elevated in extracted BAL fluid. The percentage of BAL neutrophils was also significantly increased after O2 exposure (2.8 +/- 0.6 vs 1.2 +/- 0.4 percent, p = 0.05). We conclude that an FIO2 of 50 percent inhaled for 44 h is associated with enhanced oxidative stress, stimulation of AM to release LTB4, and a small but significantly increased percentage of neutrophils recovered in BAL fluid.     

There is no activation of O2- production by alveolar macrophages and neutrophil polymorphonuclear leukocytes in rat lung transplants during the reimplantation response and acute rejection.

Activation of phagocytes (alveolar macrophages [AM] and neutrophil polymorphonuclear leukocytes [PMN]) can cause tissue damage in inflammatory lung diseases. In this study we investigated whether phagocytes contribute to the development of tissue damage in lung grafts histologically observed during two different processes: the reimplantation response and the acute rejection. Therefore, the number and profile of bronchoalveolar lavage (BAL) and blood phagocytes and their in vitro spontaneous and serum-treated-zymosan (STZ)-stimulated O2- production were assessed after allogeneic (BN to LEW) and syngeneic (LEW to LEW) transplantation of the left lung in rats. BAL PMN numbers increased during the reimplantation response, whereas during the late phase of the rejection process BAL AM and PMN numbers were increased. The O2- production by the BAL phagocytes and blood PMN were not increased at any stage. Strikingly, the STZ-stimulated O2- production by the BAL phagocytes was significantly impaired during acute rejection. Our data suggest that activation of the O2- production by bronchoalveolar phagocytes does not play an important role in the development of tissue damage in lung transplants during the reimplantation response and acute rejection. The impaired O2- production by alveolar phagocytes during acute lung rejection may contribute to the increased susceptibility for pulmonary infections after lung transplantation.     

The effect of continuous veno-venous hemofiltration or direct hemoperfusion with polymyxin B-immobilized fiber on neutrophil respiratory oxidative burst in patients with sepsis and septic shock

Neutrophil activates and injures tissues and organs during sepsis or septic shock. Blood purification therapies such as continuous veno-venous hemofiltration (CVVH) and direct hemoperfusion with polymyxin-immobilized fiber (PMX-DHP) have been used for the treatment of sepsis and septic shock, however, the effects of such therapies on neutrophil activation have previously been poorly understood. We sought to evaluate neutrophil reactive oxygen species (ROS), especially H2O2 production, in the pathophysiology of sepsis or septic shock and the effect of CVVH or PMX-DHP on neutrophil ROS. Seven critically ill septic patients requiring CVVH (and 12 matched septic patients who did not require CVVH as control) and seven septic shock patients treated with PMX-DHP were studied. We found that patients with sepsis or septic shock had significantly higher levels of neutrophil ROS compared with normal volunteers (183 +/- 42, 292 +/- 90, and 103 +/- 30) (P < 0.05, and < 0.005). Neutrophil ROS did not change over time in patients treated either with CVVH or without CVVH. In contrast, neutrophil ROS significantly inhibited PMX-DHP treatment in patients with septic shock (pretreatment; 292 +/- 88 vs. post-treatment; 205 +/- 93, P < 0.05). In conclusion, neutrophil ROS was significantly enhanced in the sepsis or septic shock affected patients. CVVH did not affect neutrophil ROS while PMX-DHP significant inhibited neutrophil ROS.     

Fractional analysis of bronchoalveolar lavage fluid cytology in cystic fibrosis patients with normal lung function. Bronchoalveolar lavage for the evaluation of anti-inflammatory treatment (BEAT) study group.

Cystic fibrosis (CF) is associated with a neutrophil dominated airway inflammation. So far bronchoalveolar lavage (BAL) studies in CF have used pooled BAL samples which may be more representative of the alveolar compartment rather than the airways. To assess whether the first sample of a BAL is more sensitive in the evaluation of airway inflammation, the authors have studied 105 stable CF patients aged 5-37 yrs with a mean forced expiratory volume in one second (FEV1) of 96+/-15% (mean+/-SD). BAL cytology of the first and pooled samples were compared to reference values obtained in children without respiratory disease. Absolute cell counts and the percentage of neutrophils were significantly increased in CF patients. If the 95% confidence interval was used as a cut-off point, 17/105 CF patients had a normal percentage of neutrophils in pooled BAL samples, but only three also had a normal percentage of neutrophils in the first BAL aliquot. Therefore, neutrophil dominated airway inflammation is more pronounced in the first, mainly bronchial, bronchoalveolar lavage sample suggesting that sequential analysis of bronchoalveolar lavage fluid may have a higher sensitivity to detect early inflammatory changes in CF patients.     

HMGB1 induces human lung endothelial cell cytoskeletal rearrangement and barrier disruption

Acute lung injury (ALI) results from loss of alveolar-capillary barrier integrity and the evolution of high-permeability pulmonary edema resulting in alveolar flooding and significant morbidity and mortality. HMGB1 is a late mediator of sepsis which uniquely participates in the evolution of sepsis and sepsis-induced ALI. The molecular events by which HMGB1 contributes to ALI remain poorly characterized. We characterized the role of HMGB1 in endothelial cell (EC) cytoskeletal rearrangement and vascular permeability, events essential to paracellular gap formation and barrier dysfunction characteristic of ALI. Initial experiments demonstrated HMGB1-mediated dose-dependent (5-20 μg/ml) decreases in transendothelial cell electrical resistance (TER) in the human pulmonary artery EC, a reflection of loss of barrier integrity. Furthermore, HMGB1 produced dose-dependent increases in paracellular gap formation in concert with loss of peripheral organized actin fibers, dissociation of cell-cell junctional cadherins, and the development of central stress fibers, a phenotypic change associated with increased contractile activity and increased EC permeability. Using siRNA strategies directed against known HMGB1 receptors (RAGE, TLR2, TLR4), we systematically determined that the receptor for advanced glycation end products (RAGE) is the primary receptor signaling HMGB1-induced TER decreases and paracellular gap formation via p38 MAP kinase activation and phosphorylation of the actin-binding protein, Hsp27. These studies add to the understanding of HMGB1-induced inflammatory events and vascular barrier disruption and offer the potential for clinical intervention in sepsis-induced ALI.     

Pulmonary neutrophil infiltration in murine sepsis: role of inducible nitric oxide synthase

Nitric oxide (NO) derived from inducible NO synthase (iNOS) contributes to the pathophysiology of acute lung injury (ALI). The effect of iNOS on pulmonary neutrophil infiltration in ALI is not known. Thus, we assessed pulmonary microvascular neutrophil sequestration through intravital videomicroscopy and pulmonary neutrophil infiltration, reflected by myeloperoxidase activity and lavage neutrophil counts, after induction of sepsis by cecal ligation/perforation in wild-type (iNOS+/+) versus iNOS-/- mice. Pulmonary microvascular neutrophil sequestration was attenuated in septic iNOS-/- versus iNOS+/+ mice (15 +/- 1 vs. 20 +/- 1 leukocytes per field, p < 0.05), but lavage neutrophil counts were greater in iNOS-/- mice (5.7 +/- 1.5% vs. 0.7 +/- 0.1%, p < 0.05) between 6 and 18 hours after cecal ligation and perforation. When iNOS+/+ bone marrow was transplanted into bone marrow-depleted iNOS-/- mice (+ to - chimeras; iNOS limited to marrow-derived inflammatory cells), septic pulmonary microvascular neutrophil sequestration and lavage neutrophil counts were restored to levels seen in septic iNOS+/+ mice. In contrast, in - to + chimeras, pulmonary neutrophil trafficking was similar to iNOS-/- mice. In vitro cytokine-stimulated neutrophil transendothelial migration was significantly greater for iNOS-/- versus iNOS+/+ neutrophils (7.9 +/- 0.7% vs. 3.8 +/- 0.6%, p < 0.05) but was independent of endothelial iNOS. Thus, neutrophil iNOS-derived NO is an important autocrine modulator of pulmonary neutrophil infiltration in murine sepsis.     

Subclinical alveolar inflammation in rheumatoid arthritis: superoxide anion, neutrophil chemotactic activity and fibronectin generation by alveolar macrophages

Interstitial lung disease (ILD) can be detected by pulmonary function testing (PFT) in 30-40% of rheumatoid arthritis (RA) patients. We assessed by bronchoalveolar lavage (BAL) the patterns of alveolitis in 21 RA patients: group 1 comprised 12 patients without evidence of ILD, and group 29 patients with clinical ILD defined by abnormal pulmonary function tests and/or chest X-ray. Cellular characteristics of BAL were studied in both groups. In addition, alveolar macrophages (AM) from patients in group 1 were isolated, and three parameters of cellular activation were studied: superoxide anion, fibronectin and neutrophil chemotactic activity generation. Total cell counts were not increased in group 1 but significantly increased in group 2 compared to controls. In group 1, 5/12 patients had elevated lymphocyte percentage (greater than 18%) suggesting subclinical lymphocyte alveolitis. In contrast, neutrophil alveolitis (greater than 4%) was found in 7/9 patients in group 2, mean percentage 12.9 +/- 4.2, compared with 1.2 +/- 6.4% in controls and 1.9 +/- 0.5% in group 1. These changes were not correlated with disease duration nor rheumatoid factor titres. Marked elevation of lymphocyte percentage was observed in patients with abnormal serum beta-2-microglobulin. Alveolar macrophages from group 1 patients released increased amounts of superoxide anion (7260 +/- 2700 vs controls 850 +/- 120 URL/5.10(5) cells), neutrophil chemotactic activity (21 +/- 4.8 vs controls 8.1 +/- 0.7 cells/HPF), and fibronectin (6.1 +/- 1.6 vs controls 1.3 +/- 0.2 ng.10(6) cells/hour). Whether or not lymphocyte alveolitis and/or AM dysfunction are pathogenic mechanisms of subsequent interstitial lung disease in patients who are still free of symptoms remains to be determined.     

Bronchoalveolar lavage eosinophilia associated with Pneumocystis carinii pneumonitis in AIDS patients. Comparative study with non-AIDS patients

Lower pulmonary tract cell populations collected by bronchoalveolar lavages (BAL) were evaluated in three groups of immunocompromised patients: HIV infected patients with Pneumocystis carinii (PC) pneumonitis (n = 22), or pneumonitis not related to PC (n = 29), and non-HIV-infected, immunocompromised patients with a PC pneumonitis (n = 18). In AIDS patients with PC pneumonitis, the cell populations were 59.3 +/- 4.5 percent alveolar macrophages (AM), 19.6 +/- 2.5 percent lymphocytes, 14.6 +/- 4.4 percent polymorphonuclear cells (PMN), and 10.3 +/- 3.6 percent eosinophils. In HIV-infected patients without PC pneumonitis, they were 76.5 +/- 3.3 percent AM, 13 +/- 2.1 percent lymphocytes, 9.2 +/- 0.3 percent PMN, and 0.6 +/- 0.2 percent eosinophils, and in non-HIV-infected, immunocompromised patients with PC pneumonitis, they were 43.9 +/- 5.7 percent AM, 30.2 +/- 4.3 percent lymphocytes, 20.4 +/- 4.7 percent PMN, and 0.9 +/- 0.4 percent eosinophils. The most striking finding was a marked BAL eosinophilia in AIDS patients with PC pneumonitis. The significance of this particular cellular pulmonary response to PC is not clear, and its consequences on the lung structures and/or PC require evaluation.     

Increased oxidized methionine residues in BAL fluid proteins in acute or chronic bronchitis.

Phagocytic cells such as alveolar macrophages (AM) or polymorphonuclear neutrophils (PMN) in the bronchoalveolar tract are a potential source of the oxygen-derived free radicals which are presumed to be involved in lung tissue damage. Previous results have shown that the methionine sulphoxide (MET(O)) content of bronchoalveolar lavage fluid (BALF) protein is a reliable parameter to indicate oxidative processes in idiopathic pulmonary fibrosis (IPF). We measured the molar ratio between MET(O) and methionine (MET) in the BALF protein from healthy nonsmokers (control group), healthy smokers and patients with acute or chronic bronchitis (AB or CB). The MET(O)/MET ratio of the nonsmoking group (n = 11) was 0.046 +/- 0.008 (mean +/- SEM). Healthy smokers (n = 8) had similar values (0.042 +/- 0.008), even though they had strongly increased AM counts in BALF. Patients with AB (n = 12) showed an increased MET(O)/MET ratio (0.191 +/- 0.031) and had high PMN but normal AM counts in BALF. Patients with CB (n = 13) showed an increase in the MET(O)/MET ratio (0.086 +/- 0.010) and moderately increased PMN and markedly increased AM counts. Taking all results together, the MET(O)/MET ratio correlated positively with the relative PMN number (r = 0.70; p less than 0.0002) and inversely with the relative AM number (r = 0.67; p less than 0.0002). In the group with CB, the MET(O)/MET ratio correlated inversely with forced expiratory volume in one second (FEV1) % pred. (r = -0.77) and FEV1/inspiratory vital capacity (IVC) % pred. (r = -0.89).(ABSTRACT TRUNCATED AT 250 WORDS)     

Alveolar macrophage immaturity in infants and young children.

Very little is known about alveolar macrophage (AM) immunological function in early childhood. Using nonbronchoscopic bronchoalveolar lavage (BAL), this study sought to compare the proportion, number, and function of AM between very young and older children. BAL fluid (BALF) leukocyte parameters were determined in 63 children, and data divided into 3 age groups: group 1 (<2 yrs), group 2 (> or =2-< or =5 yrs) and group 3 (> or =6-< or =17 years). In a further subgroup of children, AM function and immune receptor expression were assessed, and data categorized into two age groups: <2 yrs and > or =2 yrs of age. Compared to groups 2 and 3, the AM percentage in the BAL in group 1 was significantly increased (median: 98% versus 92% and 91%), as was the albumin-adjusted AM concentration. AM from children <2 yrs expressed less human leukocyte antigen (HLA)-DR (versus > or =2 yrs of age), were less effective in reducing nitro blue tetrazolium, and released less interleukin (IL)-1 and tumour necrosis factor on lipopolysaccharide stimulation. There was no difference in release of IL-6, expression of intercellular adhesion molecule-1 (CD54), and AM stimulation of allogeneic T-cells, between children <2 yrs and > or =2 yrs of age. It was concluded that the capacity of alveolar macrophage to stimulate T-cells is not enhanced in early childhood, and that immaturity of alveolar macrophage function may contribute to an increased susceptibility to respiratory infections in this age group.     

Neutrophil chemotactic factor release and neutrophil alveolitis in asbestos-exposed individuals

Alveolar neutrophil accumulation occurs in asbestosis. To evaluate a possible role for release of neutrophil chemotactic factor (NCF) in the pathogenesis of asbestosis, spontaneous NCF release from alveolar macrophages obtained by bronchoalveolar lavage (BAL) in eight individuals with asbestosis, 13 asbestos-exposed individuals without asbestosis, and five control subjects has been studied. Alveolar macrophages were incubated in medium (four hours; 37 degrees C), and neutrophil responses to the supernatants were assayed in a microchemotaxis chamber. Alveolar macrophages from subjects with asbestosis released more NCF (97 +/- 19 neutrophils per high-power field [N/HPF]) than controls (3 +/- 1 N/HPF; p less than 0.01). Alveolar macrophages from individuals with asbestos exposure and increased BAL neutrophil proportions (n = 7) released more NCF (93 +/- 24 N/HPF) than individuals with asbestos exposure and normal BAL neutrophil proportions (n = 6; 11 +/- 6 N/HPF; p less than 0.02). The results show that spontaneous NCF release occurs in asbestosis and that NCF release is associated with neutrophil alveolitis in asbestos-exposed individuals without asbestosis, suggesting a pathogenic role for NCF in mediating this neutrophil alveolitis. The results of the study also suggest that the presence of crackles is a better predictor of the presence of neutrophil alveolitis than is an abnormal chest x-ray film.     

Correlation of bronchoalveolar lavage findings to severity of Pneumocystis carinii pneumonia in AIDS. Evidence for the development of high-permeability pulmonary edema.

We correlated bronchoalveolar lavage findings with the clinical course and outcome of Pneumocystis pneumonia. Forty-eight patients with AIDS and a confirmed diagnosis of P carinii pneumonia were studied. Patients with additional pulmonary infections were excluded. On the basis of BAL findings, they were divided into those with a low neutrophil count (less than 5 percent) and those with a high neutrophil count (greater than or equal to 5 percent). Sixteen patients with AIDS but without PCP served as a control group. All BAL fluid samples from the control group showed a low neutrophil count. The group with PCP and a high neutrophil count had more severe respiratory compromise and greater morbidity than the group with PCP and a low neutrophil count. Mortality rate was not different. The group showing a high BALF neutrophil count also showed a higher BALF protein concentration, a higher ratio of BALF protein concentration to plasma protein concentration, and the presence of alpha 2-globulins compared with other groups. These findings suggest that increased alveolar-capillary permeability occurs during severe PCP.     

Increased expression of apoptosis signalling receptors by alveolar macrophages in sarcoidosis.

The Fas receptor (FasR) and the tumour necrosis factor (TNF) receptor 55/60 kDa (TNFR1) are recognized as apoptosis signalling receptors. They are known to be expressed by lymphocytes in association with immune regulation and immunological disorders. This study aimed to investigate the expression of FasR and TNFR1 by alveolar macrophages (AM) in patients with sarcoidosis. Bronchoalveolar lavage (BAL) was performed in 12 patients with active sarcoidosis and 11 control subjects. BAL cells were characterized by monoclonal antibodies using a peroxidase-antiperoxidase method. Both FasR and TNFR1 were expressed on a higher percentage of AM in sarcoidosis with respect to control subjects (mean +/-sem 40.8+/-3.1% versus 14.9+/-1.7%, p<0.001 and 61.9+/-3.3% versus 23.1+/-4.1%, p<0.001, respectively). There was a close relationship between the expression of FasR and TNFR1 on AM (r = 0.86, p<0.001). The percentages of FasR+ AM and TNFR1+ AM were in direct proportion to the percentage of BAL lymphocytes (r = 0.75 and 0.84), the CD4/CD8 ratio (r = 0.78 and 0.78), and the percentage of the CD14+ AM subset (r = 0.77 and 0.87), p<0.001 for all correlations. This study indicates that alveolar macrophages expressing apoptotic receptors are increased in patients with active sarcoidosis. Further studies are required to determine whether these alveolar macrophages from patients with sarcoidosis undergo apoptosis more readily than those from control subjects.     

Neutrophil short-lived oxidant production: enhancement following onset of sepsis-induced lung injury.

Generation of superoxide anion (O2-) by activated neutrophils (PMN) is implicated in the pathogenesis of endothelial cell injury in sepsis. To quantitate this phenomenon we studied the kinetics of O2- production by PMN following in vivo and in vitro exposure to Pseudomonas aeruginosa. PMN were isolated from young swine before and after a 1-hr infusion with 5 x 10(8) organisms/ml at 0.3 ml/20 kg/min. Baseline PMN were studied in an in vitro system where 1 x 10(6) porcine PMN were incubated with live Pseudomonas for 1 hr at 37 degrees C. Neutrophils from septic pigs exhibited a significantly increased (P less than 0.05) initial rate of O2 production, which was 125% greater at 2 min following initial stimulation than saline controls (P less than 0.001). Neutrophils exposed in vitro displayed a similar enhancement of the rate of O2- production; however, the rate was 3.6 times greater than that noted in vivo. The in vivo change in PMN oxidant generation was associated with a rise in both extravascular lung water (EVLW) and increased bronchoalveolar lavage protein (BAL-P) content. These data suggest that sepsis-induced acute lung injury is accompanied by "priming" of circulating PMN; however, important factors are present in the circulation in sepsis that serve to attenuate the damaging potential of PMN oxidant species.     

miR-126-5p expression in the plasma of patients with sepsis-induced acute lung injury and its correlation with inflammation and immune function

Objective

This work was implemented to elucidate the miR-126-5p expression in the plasma of patients with sepsis-induced acute lung injury (ALI) and its correlation with inflammation and immune function.

Methods

The peripheral blood of patients with sepsis-induced ALI was obtained, and the levels of inflammatory factors (interleukin-6 [IL-6], C-reactive protein [CRP], and procalcitonin [PCT]) were determined. Meanwhile, T lymphocyte subsets (CD3+, CD4+, and CD8+), and immunoglobulins (IgA, IgM, and IgG) were tested. miR-126-5p and TRAF6 mRNA expression in plasma was assessed. Receiver operating characteristic (ROC) curve was performed to assess the diagnostic accuracy of miR-126-5p in sepsis without ALI and sepsis with ALI. Correlation between miR-126-5p expression and clinical indicators was analyzed. The targets of miR-126-5p were predicted using the bioinformatics method, and the direct targets were verified through investigations.

Results

miR-126-5p expression in plasma of patients with sepsis-induced ALI was reduced than that of patients with sepsis without ALI. miR-126-5p expression was negatively correlated with IL-6, CRP, and PCT but positively correlated with IgA, IgM, and IgG as well as CD3+, CD4+, and CD8+ in patients with sepsis-induced ALI. ROC curve suggested that miR-126-5p (AUC: 0.777; 95%CI: 0.689–0.866) could distinguish patients with sepsis with ALI from patients with sepsis without ALI. TRAF6 expression in patients with sepsis-induced ALI was higher than that in patients with sepsis without ALI. TRAF6 was a target gene of miR-126-5p,

Conclusion

This research highlights that miR-126-5p is reduced in the plasma of patients with sepsis-induced ALI, and miR-126-5p relates to systemic inflammation and immune function indicators.     

Alterations of Adhesion Molecule Expression and Inflammatory Mediators in Acute Lung Injury Induced by Septic and Non-septic Challenges

The lung is frequently the first failing organ during the sequential development of multiple organ dysfunction under both septic or non-septic conditions. The present study compared polymorphisms of tumor necrosis factor (TNFα), monocyte chemoattractant protein-1 (MCP-1), and adhesion molecule (AM) expression on circulating, recruited, and migrating leukocytes in the development of lung injury after induction of acute pancreatitis (AP) or abdominal sepsis by cecal ligation and puncture (CLP). Pulmonary alveolar barrier and endothelial barrier permeability dysfunction were measured. The expression of AMs (CD11b, CD11b/c, CD31, CD54 and CD62L) on leukocytes isolated from blood, lung tissue, and bronchoalveolar space were measured by flowcytometry. Plasma exudation to the interstitial tissue and the bronchoalveolar space significantly increased 1 and 3 hours after induction of pancreatitis and to the bronchoalveolar space from 6 hours after sepsis. Bronchoalveolar levels of MCP-1 significantly increased earlier than plasma exudation to the alveoli in both pancreatitis and sepsis. Alterations in expression of adhesion molecules on bronchoalveolar lavage (BAL) leukocytes can represent a marker reflecting leukocyte activation in the lung tissue, since both BAL and lung tissue leukocytes showed similar patterns of changes. Expression of adhesion molecules on circulating leukocytes increased 1 hour after induction of pancreatitis. Activating phenotypes of circulating, lung tissue and bronchoalveolar leukocytes may thus be responsible for the-development and severity of secondary lung injury.Supported by grants from the Swedish Research Council (grant no 11236), the Crafoord Foundation, Ake Wiberg Foundation, Maj Bergvall Foundation, Golje Foundation and Clas Groschinsky Foundation.     

Pentamidine aerosol increases the number of alveolar macrophages in HIV-infected patients

In order to determine the possible effect of aerosolized pentamidine on the cellular composition of the bronchoalveolar lavage fluid in HIV-infected patients, differential counts of 22 consecutive patients who had been rebronchoscopied after 3-19 months were reviewed. Eleven patients were started on pentamidine prophylaxis subsequent to their first presentation. Eleven patients had never taken pentamidine or had discontinued the prophylactic regimen. Compared to first bronchoscopy, the bronchoalveolar lavage (BAL) from patients on regular prophylaxis revealed a significant increase in absolute alveolar macrophage (AM) counts at second presentation (20.8 +/- 11.2 to 50.3 +/- 39.4 x 10(5) cells/100 ml BAL; P less than 0.01). The AM counts of those without pentamidine remained essentially unchanged. Lymphocytes, including CD4 and CD8 subtypes, and neutrophils did not change over time in either group. The results of this retrospective analysis suggest that, in addition to its antimicrobial action, pentamidine may modulate local lung defence mechanisms, particularly by increasing the absolute number of AM.     

Increased alveolar plasminogen activator in early asbestosis

Alveolar macrophage-derived plasminogen activator (PA) activity is decreased in some chronic interstitial lung diseases such as idiopathic pulmonary fibrosis and sarcoidosis but increased in experimental models of acute alveolitis. Although asbestos fibers can stimulate alveolar macrophages (AM) to release PA in vitro, the effect of chronic asbestos exposure of the lower respiratory tract on lung PA activity remains unknown. The present study was designed to evaluate PA activity of alveolar macrophages and bronchoalveolar lavage (BAL) fluid in asbestos-exposed sheep and asbestos workers. Forty-three sheep were exposed to either 100 mg UICC chrysotile B asbestos in 100 ml phosphate-buffered saline (PBS) or to 100 ml PBS by tracheal infusion every 2 wk for 18 months. At Month 18, chest roentgenograms were analyzed and alveolar macrophage and extracellular fluid PA activity were measured in samples obtained by BAL. Alveolar macrophage PA activity was increased in the asbestos-exposed sheep compared to control sheep (87.2 +/- 17.3 versus 41.1 +/- 7.2 U/10(5) AM-24 h, p less than 0.05) as was the BAL fluid PA activity (674.9 +/- 168.4 versus 81.3 +/- 19.7 U/mg alb-24 h, p less than 0.01). Among the asbestos-exposed sheep, 10 had normal chest roentgenograms (Group SA) and 15 had irregular interstitial opacities (Group SB). Strikingly, whereas Group SA did not differ from the control group in BAL cellularity or PA activity, Group SB had marked increases in alveolar macrophages (p less than 0.005), AM PA activity (p less than 0.02), and BAL PA activity (p less than 0.001) compared to the control group.(ABSTRACT TRUNCATED AT 250 WORDS)