Keratinocyte growth factor pretreatment is associated with decreased macrophage inflammatory protein-2alpha concentrations and reduced neutrophil recruitment in acid aspiration lung injury

A two-hit model of acid aspiration was used to examine the effect of keratinocyte growth factor (KGF) on chemokine levels and neutrophil recruitment into the lung. Mice were subjected to cecal ligation and puncture and then either KGF or saline, intratracheally (i.t.). Forty-eight hours later, the mice were given i.t. acid. After 8 h, neutrophil counts in bronchoalveolar lavage (BAL) fluid were significantly decreased in animals pretreated with KGF (23 +/- 4 x 10(3)/mouse) compared with saline (74 +/- 2 x 10(3)/mouse). In addition, the BAL fluid IL-6 levels were decreased in the KGF-treated group (88+/- 44 pg/mL) compared with the saline group (166 +/- 34 pg/mL). To examine the mechanism behind the KGF-induced reduction in neutrophil influx, the murine chemokines KC and macrophage inflammatory protein (MIP)-2alpha were measured. KC levels in plasma and BAL fluid were not significantly different between the treatment groups. Likewise, levels of MIP-2alpha in plasma were not affected by KGF treatment. However, 8 h after acid aspiration, MIP-2alpha concentrations were significantly lower in the KGF-treated group. The ratio of MIP-2alpha in BAL fluid versus plasma was lower in the KGF group (0.72 +/- 0.28) than in the saline group at 3 h (2.23 +/- 0.93) and also significantly lower in the KGF group (3.02 +/- 0.78) compared with the saline group (6.23 +/- 1.19) at 8 h. In this study, KGF pretreatment after acid aspiration was associated with reduced neutrophil recruitment into the lung and a decrease in MIP-2alpha gradients between BAL fluid and plasma.     

Cytokine expression in severe pneumonia: a bronchoalveolar lavage study.

OBJECTIVE: To assess the cytokine expression (tumor necrosis factor-alpha [TNF-alpha], interleukin [IL]-1beta, and IL-6) in severe pneumonia, both locally (in the lungs) and systemically (in blood). DESIGN: Prospective sequential study with bronchoalveolar lavage (BAL) and blood sampling. SETTING: Six-bed respiratory intensive care unit of a 1,000-bed teaching hospital. PATIENTS: Thirty mechanically ventilated patients (>48 hrs) were allocated to either the pneumonia group (n = 20) or a control group (n = 10). INTERVENTIONS: Protected specimen brush and BAL samples for quantitative cultures, and serum and BAL fluid TNF-alpha, IL-1beta, and IL-6 levels were measured on days 1, 3, and 7. In the control group, the procedure was done on day 1 only. MEASUREMENTS AND MAIN RESULTS: Serum TNF-alpha levels were significantly higher in patients with pneumonia compared with controls (35 +/- 4 vs. 17 +/- 3 pg/mL, respectively, p = .001). IL-6 levels in serum and BAL fluid were higher in pneumonia than in control patients (serum, 837 +/- 260 vs. 94 +/- 35 pg/mL, respectively, p = .017; BAL fluid, 1176 +/- 468 vs. 234 +/- 83 pg/mL, respectively, p = .05). On days 1, 3, and 7 in patients with pneumonia, IL-1beta levels turned out to be higher in BAL fluid than in serum (71 +/- 17 vs. 2 +/-1 pg/mL on day 1; 49 +/- 8 vs. 6 +/- 2 pg/mL on day 3; and 47 +/- 16 vs. 3 +/- 2 pg/mL on day 7 for BAL fluid and serum, respectively, p < .05). No significant correlation between BAL fluid cytokine levels and lung bacterial burden was shown in presence of antibiotic treatment. Although no clear relationship was found between BAL fluid and serum cytokines and mortality, there was a trend toward higher serum IL-6 levels in nonsurvivors (1209 +/- 433 pg/mL) with pneumonia compared with survivors (464 +/- 260 pg/mL). In addition, serum TNF-alpha and IL-6 correlated with multiple organ failure score (r2 = .36, p = .004 for both) and with lung injury score (r2 = .30, p = .01, and r2 = .22, p = .03, for TNF-alpha and IL-6, respectively). CONCLUSIONS: The present study describes the lung and systemic inflammatory response in severe pneumonia. The lung cytokine expression seems to be independent from the lung bacterial burden in the presence of antibiotic treatment. Because of the limited sample size, we did not find a clear relationship between serum and BAL fluid cytokine levels and outcome.     

Platelet-activating factor acetylhydrolase is increased in lung lavage fluid from patients with acute respiratory distress syndrome

OBJECTIVE: Platelet-activating factor (PAF) is a proinflammatory phospholipid that may contribute to inflammation in the acute respiratory distress syndrome (ARDS). PAF acetylhydrolase (PAF-AH) degrades PAF and regulates its biological activity. We characterized PAF-AH in bronchoalveolar lavage fluid from ARDS patients (n = 33, 22 survivors), patients at risk for ARDS (n = 6), and healthy controls (n = 6). DESIGN: Bronchoalveolar lavage was performed during acute (<96 hrs from onset), plateau (6 to 12 days), and late (> or = 14 days) phases of ARDS. PATIENTS: Intubated patients with ARDS or a risk factor for ARDS. MEASUREMENTS AND MAIN RESULTS: In ARDS, total bronchoalveolar lavage PAF-AH activity was markedly increased in the acute phase (87 +/- 89 mU/mL, n = 33) and then decreased in the plateau (23 +/- 14 mU/mL, n = 10) and late phases (19 +/- 14 mU/mL, n = 7) (p = .003). Total bronchoalveolar lavage PAF-AH activity during the acute phase of ARDS was also increased as compared with patients at risk for ARDS (16 +/- 13 mU/mL, n = 6) and healthy controls (3 +/- 3 mU/mL, n = 6) (p < .001). In contrast, plasma PAF-AH activities were the same in controls (3215 +/- 858 mU/mL, n = 6), in patients at risk for ARDS (3606 +/- 1607 mU/mL, n = 6), and during the acute phase of ARDS (3098 +/- 2395 mU/mL, n = 33) (p = .18). PAF-AH mRNA was present in alveolar macrophages in the acute phase of ARDS (five of six) and in at-risk patients (two of three) but not in healthy controls. CONCLUSIONS: PAF-AH activity is increased in bronchoalveolar lavage fluid from patients with ARDS. Likely sources include leakage of plasma PAF-AH into alveoli or release of PAF-AH from injured cells; however, the presence of PAF-AH mRNA in alveolar macrophages suggests that PAF-AH may be actively synthesized in the lungs of patients with ARDS. PAF-AH activity in the lungs of ARDS patients may regulate inflammation caused by PAF and related oxidized phospholipids generated in the inflammatory response.     

Interleukin-2 involvement in early acute respiratory distress syndrome: relationship with polymorphonuclear neutrophil apoptosis and patient survival

OBJECTIVE: To determine blood and lung alveolar concentrations of interleukin (IL)-2 in acute respiratory distress syndrome (ARDS) and their relationship with polymorphonuclear neutrophil (PMN) apoptosis and patient survival. DESIGN: Prospective cohort study. SETTING: Medical and surgical intensive care units (ICUs; Canada) and the intensive care department (Belgium). PATIENTS: Nineteen consecutive patients with ARDS, 14 non-ARDS ICU patients, and 20 healthy volunteers. INTERVENTIONS: Blood samples and bronchoalveolar lavages (BAL) obtained via venous puncture and by fiberoptic bronchoscopy in the first 72 hrs after the onset of ARDS. MEASUREMENTS AND MAIN RESULTS: One early point concentration of IL-2 was measured in both blood and BAL fluids of the three groups. In vivo alveolar PMN apoptotic index in BAL fluids and the influence of BAL fluid exposure on normal blood PMN spontaneous apoptosis in vitro were evaluated. Blood IL-2 was significantly lower in patients with ARDS compared with non-ARDS ICU patients and controls. In contrast, IL-2 in BAL fluids of patients with ARDS was dramatically elevated compared with non-ARDS ICU patients and controls. ARDS survivors exhibited lower early IL-2 blood levels than nonsurvivors and generally had a higher IL-2 lung content Lung alveolar PMN apoptosis in vivo was lower in patients with ARDS in comparison with controls. This apoptotic index was correlated with corresponding IL-2 alveolar levels in patients with ARDS. Exposure of normal blood PMN to BAL fluids from patients with ARDS delayed apoptosis in vitro. Immunodepletions of IL-2, granulocyte-macrophage colony stimulating factor, and a combination of both cytokines from BAL fluids of ARDS patients significantly restored PMN apoptosis. The recovery of PMN apoptosis was more effective when IL-2 was depleted in BAL fluids from ARDS survivors compared with nonsurvivors. CONCLUSIONS: Opposite and disproportional concentrations of IL-2 are observed in blood and lung fluids of patients with early ARDS. IL-2 significantly contributes (with granulocyte-macrophage colony stimulating factor) to the inhibition of PMN apoptosis in BAL fluids of patients with ARDS. Early low blood IL-2 and high IL-2-driven inhibition of PMN apoptosis are beneficial to survivors. Thus, IL-2 is a new candidate for monitoring in early ARDS and an interesting indicator of prognosis.     

Vascular endothelial growth factor in bronchoalveolar lavage from normal subjects and patients with diffuse parenchymal lung disease

Vascular endothelial growth factor (VEGF) is a potent angiogenic agent that is expressed by epithelial cells in the mature lung of various animal species. We hypothesized that VEGF levels in lower respiratory tract secretions may vary with age or with lung inflammation in human beings. We measured VEGF165 in bronchoalveolar lavage fluid (BALF) from normal volunteers (NVs) of varying age and from patients with cystic fibrosis (CF), sarcoidosis, or idiopathic pulmonary fibrosis (IPF). A considerable gradient in VEGF levels was found with relatively high VEGF concentrations in BALF as compared with serum VEGF. VEGF levels were 303 +/- 34 pg/mL (mean +/- SEM) in serum samples from patients with CF (N = 9) versus 122 +/- 16 pg/mL for the comparable, youngest group of NVs (P < .01). BALF VEGF concentrations were 165 +/- 17 pg/mL for CF upper lobe BALF (N = 9), 140 +/- 17 pg/mL for CF lower lobe BALF (N = 9), and 235 +/- 24 pg/mL for young adult NVs (N = 29). Serum VEGF levels did not differ significantly between NVs and patients with interstitial lung disease, but mean BALF VEGF levels declined significantly with advancing age in NVs and were significantly depressed in patients with IPF (32 +/- 6 pg/mL) as compared with all other groups, including the oldest group of NVs (134 +/- 13 pg/mL, P < .0001). We conclude that a considerable gradient in VEGF concentration exists from epithelial bronchoalveolar surface fluid to serum. Concentrations of VEGF in lower respiratory tract secretions vary with age and are significantly depressed in IPF.     

Acute lung injury and acute respiratory distress syndrome at the intensive care unit of a general university hospital in Brazil. An epidemiological study using the American-European Consensus Criteria

OBJECTIVES: To determine: (1) the frequency of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS); (2) the mortality associated with these syndromes and (3) the influence of risk factors, comorbidities and organ system dysfunction in the mortality of ALI patients. DESIGN: Prospective cohort study. SETTING: Intensive care unit (ICU) of a general university hospital in Brazil. PATIENTS AND PARTICIPANTS: All patients that remained in the ICU for more than 24 h were evaluated regarding the presence/development of ALI/ARDS according to the 1994 American-European Consensus Conference. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: One thousand three hundred and one patients were studied and analyzed regarding mortality, risk factors, comorbidities and organ system dysfunction(s). The frequency of ALI was 3.8% (50), of which ARDS was 2.3% (30) and ALI/non-ARDS 1.5% (20) (p=0.15). The ICU mortality of patients with ALI was 44.0%; in ALI/non-ARDS and ARDS patients it was 40.0% and 46.7%, respectively (p=0.43). The hospital mortality of ALI patients was 48.0%; in ALI/non-ARDS and ARDS patients it was 50.0% and 46.7%, respectively (p=0.21). A multivariate analysis demonstrated that renal (ICU and hospital: p=0.002) and hematological dysfunction (ICU: p=0.008; hospital: p=0.02) were independently associated with ICU and hospital mortality in ALI patients. CONCLUSIONS: (1) The frequency of ALI was 3.8%, of which the frequency of ARDS was 2.3% and of ALI/non-ARDS 1.5%; (2) The ICU and hospital mortality of ALI patients was 44.0% and 48.0%, respectively; mortality rates of ARDS and ALI/non-ARDS did not differ significantly; (3) Renal and hematological dysfunction were associated with mortality in ALI patients.     

Complement activation and increased alveolar-capillary permeability after major surgery and in adult respiratory distress syndrome

The concentrations of C3a des Arg were measured in bronchoalveolar fluid (BAL) and plasma from 12 patients with adult respiratory distress syndrome (ARDS). Compared with 32 controls, all patients had increased BAL fluid levels (p less than .001), and nine of 12 had increased plasma levels (p less than .001) of this split product from the third complement component. Reduced total hemolytic activity (CH50) in serum was seen in five patients (p less than .01). As an indication of damage to the alveolar-capillary barrier, ten of the 12 ARDS patients had elevated albumin concentrations in BAL fluid (p less than .001). These signs of complement activation and lung tissue damage are not specific for ARDS. Thus, in 15 patients investigated preoperatively and postoperatively, we found that major surgery induced a significant increase of BAL fluid C3a (p less than .01) and plasma C3a (p less than .02), a significant reduction of CH50 (p less than .001), and a significant increase of BAL fluid albumin (p less than .02). Similar values of CH50 and plasma C3a were seen in ARDS and after surgery (p greater than .05). Of the 12 ARDS patients, eight had increased BAL fluid concentrations of C3a (p less than .001), and ten had increased BAL fluid levels of albumin (p less than .001) compared with the post-surgical patients. Measuring complement consumption in blood by these techniques is of limited value in ARDS due to the lack of specificity. BAL fluid albumin has a similar degree of sensitivity and specificity for ARDS as does BAL fluid C3a.(ABSTRACT TRUNCATED AT 250 WORDS)     

Oxygen delivery-dependent oxygen consumption in acute respiratory failure

OBJECTIVE: To investigate whether oxygen consumption (VO2) is dependent on oxygen delivery (DO2) in adult respiratory distress syndrome (ARDS) and non-ARDS acute respiratory failure. DESIGN: Intervention study of a consecutive sample of patients admitted to the ICU with the diagnosis of acute respiratory failure. SETTING: Tertiary care center. PATIENTS: Thirteen consecutive patients with a diagnosis of ARDS and 11 with a diagnosis of respiratory failure not due to ARDS. Patients were monitored with an oximetric pulmonary artery catheter and mechanically ventilated. INTERVENTIONS: DO2 was decreased by the application of positive end-expiratory pressure (PEEP) (20 cm H2O), and subsequently increased by an iv infusion of dobutamine (10 micrograms/kg.min). RESULTS: After the application of PEEP, DO2 decreased significantly in both groups. However, VO2 decreased significantly (p less than .01) only in the ARDS group. When dobutamine was infused, DO2 increased significantly (p less than .01) in both groups, but VO2 increased only in ARDS patients. DO2 correlated significantly with VO2 both in ARDS (r2 = .81, p less than .01) and in non-ARDS (r2 = .38, p less than .05) patients. The correlation coefficient was significantly higher for ARDS than for non-ARDS patients. Comparing the slopes of the regression lines, a stronger dependency of VO2 on DO2 was found in ARDS than in non-ARDS respiratory failure (p less than .001). The oxygen extraction ratio correlated with DO2 in non-ARDS patients (r2 = .49, p less than .05), but not in ARDS patients. CONCLUSIONS: VO2 is dependent on DO2 over a wide range of DO2 values in acute respiratory failure. This dependency phenomenon is much stronger in ARDS than in respiratory failure due to other causes. Due to the abnormal dependency of VO2 on DO2, changes in the oxygenation status may not be reflected by changes in mixed venous oxygen saturation in ARDS.     

Nitric oxide suppresses the secretion of vascular endothelial growth factor and hepatocyte growth factor from human mesenchymal stem cells

The production of growth factors such as vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) by human bone marrow mesenchymal stem cells (MSCs) may play an important role in their paracrine effects on proliferation, differentiation, and protection. NO is produced during ischemia and may affect MSC function. However, it is unknown whether NO alters the production of VEGF and HGF from MSCs. To study this, human MSCs were stimulated to produce growth factors with TNF or LPS with and without various doses of NO donors or NOS inhibitors. We found that FK409, an NO donor, significantly suppressed the production of VEGF and HGF from human MSCs. Vascular endothelial growth factor in the supernatants of cells treated by 20 nM FK409 (497 +/- 19 pg/mL) was significantly lower compared with controls (625 +/- 34 pg/mL). Similarly, NO donor significantly suppressed the amount of HGF from controls (118 +/- 3 to 40 +/- 2 pg/mL) after treatment with 20 nM FK409. NO donor also abolished the augmentation of VEGF production induced by LPS. The amount of VEGF in the supernatant was 571 +/- 11 pg/mL when cells were treated with 20 nM FK409 and LPS (200 ng/mL), which was significantly lower than groups treated with LPS alone (941 +/- 30 pg/mL). This study constitutes an initial report regarding the effect of NO on human MSC growth factor production.     

Tumor necrosis factor in serum and in bronchoalveolar lavage of patients at risk for the adult respiratory distress syndrome

Tumor necrosis factor-alpha (TNF) production was analyzed in 30 mechanically ventilated patients at high risk for the adult respiratory distress syndrome (ARDS) as defined by the presence of septic syndrome or following multiple trauma. Ten patients mechanically ventilated with acute cerebral hemorrhage were studied as a control group. Serum samples were drawn on entry into the study every 30 minutes for 90 minutes (0hr), 24 hours (24hr), and 48 hours (48hr) after enrollment. Bronchoalveolar lavage (BAL) was performed on the first and third day serum and BAL fluid were essayed for TNF content. No detectable amount of TNF was observed in 10 nonseptic controls. Production of TNF did not vary over the study period and was observed not only in patients with septic syndrome but also in patients without sepsis. Tumor necrosis factor did not correlate with mortality, severity of illness, and clinical parameters. Patients developing ARDS showed a significantly higher concentration of TNF in BAL than in serum (96 ± 25v 28 ± 27 pg/mL at 0hr; 91 ± 29 v 22 ± 25 pg/mL at 48hr; P < .05). These data support the concept of local pulmonary production of this cytokine in ARDS.     

急性呼吸窘迫综合征患者肺泡微环境对肺成纤维细胞生物学活性的影响

目的探讨不同程度急性呼吸窘迫综合征（ARDS）肺泡微环境的变化对肺成纤维细胞（LF）的影响。 方法以2014年1月至2016年12月绍兴市人民医院重症监护病房（ICU）收治的58例符合ARDS诊断标准的患者,依据患者氧合指数和柏林定义标准将患者分为轻度组（26例）、中度组（15例）、重度组（17例）,另纳入10例行机械通气但无肺部疾病患者作为无肺损伤组。所有入选患者均进行支气管肺泡灌洗,留取支气管肺泡灌洗液（BALF）标本,酶联免疫吸附法（ELISA）检测其中白细胞介素1β（IL-1β）、角质细胞生长因子（KGF）和肝细胞生长因子（HGF）水平,并进行蛋白定量及细胞计数。同时,体外培养肺成纤维细胞系MRC-5细胞,与各组患者BALF共培养,采用Transwell法检测细胞迁移能力,采用Western-blotting法检测各组细胞Collagen Ⅰ和血小板源性生长因子α受体（PDGF-Rα）表达。 结果与无肺损伤组比较,ARDS轻度组、中度组及重度组患者的IL-1β[12（8,21）、776（449,943）、802（691,1 004）、886（548,1 130）ng/L]、KGF[2.0（1.0,2.2）、19.0（15.8,24.5）、41.4（36.2,57.3）、64.7（49.2,82.1）ng/L]、HGF[90（75,106）、514（373,785）、867（674,1 248）、940（660,1 344）ng/L]、蛋白含量[（0.09 ± 0.03）、（0.29 ± 0.10）、（0.45 ± 0.09）、（0.68 ± 0.16）g/L]及细胞总数[（2.4 ± 0.6）、（16.5 ± 2.1）、（17.8 ± 2.0）、（18.2 ± 2.0）× 10⁹个/mL]均明显升高（Z=26.182、55.871、36.354,F=72.860、177.291,P均<0.05）,且与重度组患者比较,轻度组及中度组患者的KGF水平及蛋白含量显著降低（P均<0.05）,轻度组仅HGF水平及总细胞数明显降低（P均<0.05）,而ADRS各组间IL-1β比较,差异均无统计学意义（P均>0.05）。同时,与无肺损伤组比较,ARDS各组间趋化指数均明显升高（F=12.291,P=0.003）,且重度ARDS组患者明显高于轻度及中度组患者（P均<0.05）。四组间CollagenⅠ蛋白及PDGF-Rα蛋白比较,差异均有统计学意义（F=358.943,P=0.001;F=4.574,P=0.002）。ARDS各组CollagenⅠ蛋白明显高于无肺损伤组,且中度、重度组明显高于轻度组（P均<0.05）。而PDGF-Rα蛋白在无肺损伤组和轻度组几乎无表达,但在中度、重度组均有明显表达（P均<0.05）。 结论随着ARDS程度的加重,BALF中KGF、HGF明显上升,BALF可通过诱导LF表达PDGF-Rα和CollagenⅠ,促进LF的迁移与分化。     

Relationship between tumor necrosis factor-alpha and ammonia in patients with hepatic encephalopathy due to chronic liver failure

BACKGROUND: We have recently demonstrated that in humans, circulating levels of tumor necrosis factor-alpha (TNF) correlate positively with severity of hepatic encephalopathy (HE) due to chronic liver failure.AIM. The main aim of this larger population study is to determine the relationship between TNF and ammonia in patients with HE and chronic liver failure due to liver cirrhosis. METHODS: Circulating levels of TNF and ammonia were measured in 108 patients with liver cirrhosis due to various etiologies in various clinical grades of HE (grades 0-4). TNF concentrations were measured in venous serum using commercially available solid-phase high sensitivity enzyme-linked immunosorbent assay. Ammonia levels were determined in venous plasma by the enzymatic method, using the glutamate dehydrogenase reaction. RESULTS: The mean+/-SEM values of circulating levels of TNF and ammonia at presentation in patients with grade 0 of HE (n = 30) were 3.89+/-0.2 pg/mL and 49.8+/-2.8 microg/mL respectively, in patients with grade 1 of HE (n = 26) were 8.56+/-0.34 pg/mL and 101.6+/-6.5 microg/mL respectively, in patients with grade 2 of HE (n = 22) were 11.59+/-0.48 pg/mL and 160.3+/-10.7 microg/mL respectively, in patients with grade 3 of HE (n = 20) were 19.98+/-0.94 pg/mL and 228.8+/-16.1 microg/mL respectively, and in patients with grade 4 of HE (n = 10) were 51.53+/-8.59 pg/mL and 284.2+/-20.3 microg/mL respectively. A significant positive correlation was found between circulating levels of TNF and those of ammonia (r = 0.62, P< 0.0001), and also between circulating levels of both substances and severity of HE in these patients (r = 0.95, P<0.0001, and r = 0.9, P<0.0001 respectively). TNF and ammonia were both significant independent predictors of severity of HE (P<0.0001 for both variables). CONCLUSION: The results of this study demonstrate a significant relationship between TNF and ammonia in patients with chronic liver failure and HE, and so strengthen the suggestion that TNF could be strongly involved in the pathogenesis of HE in these patients. Hence, we suggest a new theory in the pathogenesis of HE, the "TNF theory".     

Triggering receptors expressed on myeloid cells in pulmonary aspiration syndromes

OBJECTIVE: To investigate the potential role of serum and alveolar soluble triggering receptor expressed on myeloid cells (sTREM-1) as a biological marker of pulmonary aspiration syndromes. DESIGN: Prospective cohort study. SETTING: University-affiliated intensive care unit. PATIENTS: Seventy-five patients with pulmonary aspiration and 13 controls receiving mechanical ventilation. INTERVENTIONS: Blood and bronchoalveolar lavage (BAL) fluid samples were collected on enrollment. Soluble TREM-1 levels were measured by an enzyme-linked immunosorbent assay. MEASUREMENTS AND RESULTS: Thirty-eight of 75 participants had documented BAL culture-positive pulmonary aspiration. While circulating levels of sTREM-1 were comparable between those with aspiration syndromes (19.81 +/- 12.09 pg/ml) and controls (15.96 +/- 11.16 pg/ml) (p=0.27), the alveolar levels of sTREM-1 were higher in patients with culture-positive pulmonary aspiration (344.41 +/- 152.82 pg/ml) compared with those culture-negative pulmonary aspiration (142.76 +/- 89.88 pg/ml; p < 0.001). A cut-off value of 250 pg/ml for alveolar sTREM-1 achieved a sensitivity of 65.8% (95% CI 48.6-80.4) and a specificity of 91.9% (95% CI 78.1-98.2) with an area under the curve of 0.87 (95% CI 0.78-0.94). CONCLUSIONS: Alveolar sTREM-1 levels can be a potential biomarker for distinguishing BAL culture-positive from BAL culture-negative pulmonary aspiration.     

Cytokeratin 19 fragments in patients with acute lung injury: a preliminary observation

Objective Cytokeratin 19 (CK19) is a specific cytoskeletal structure for alveolar epithelium. We hypothesized that the levels of CK19 fragments in bronchoalveolar lavage (BAL) fluid could serve as an index of epithelial injury and as a prognosis marker in patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). The aims of our study were, in patients with ALI/ARDS: (1) to measure CK19 fragments concentrations in BAL fluid, (2) to assess its prognostic value, and (3) to identify the cellular source of CK19 in the alveolar space.Design Prospective preliminary study.Setting University hospital surgical ICU.Patients Twenty-two mechanically ventilated patients with ALI/ARDS and 10 non-ventilated control patients. Plasma samples were obtained for 11 ALI/ARDS patients.Measurements and results The concentration of BAL CK19 fragments was higher in patients (median 4916 pg/ml, 25th–75th percentile 2717–10533) than in controls (2208 pg/ml. 767–3923; p = 0.05), and higher in 10 non-survivors (7051 pg/ml, 4372–13371) than in 12 survivors (2888 pg/ml, 1315–5639; p = 0.03 among ALI/ARDS patients). BAL CK19 fragment concentration did not correlate with simplified acute physiologic score, lung injury score or PaO₂/FIO₂ ratio, but correlated positively with BAL albumin concentration (p = 0.002) and with number of BAL macrophages (p = 0.0001). Plasma CK19 fragment concentrations were 10 times lower than those in BAL. Immunohistochemical staining for CK19 showed a strong labelling of injured detached epithelial cells and hyperplastic epithelium in ALI/ARDS lung samples.Conclusion CK19 fragment concentrations were found to be elevated in BAL fluid in ALI/ARDS patients compared with control subjects. High BAL CK19 fragment levels were associated with a poor prognosis.Electronic supplementary material The electronic reference of this article is . The online full-text version of this article includes electronic supplementary material. This material is available to authorised users and can be accessed by means of the ESM button beneath the abstract or in the structured full-text article. To cite or link to this article you can use the above reference.     

Phospholipases A2 and platelet-activating-factor acetylhydrolase in patients with acute respiratory distress syndrome

OBJECTIVE: Phospholipases A2 (PLA2) comprise a family of enzymes probably implicated in the development of acute respiratory distress syndrome (ARDS). The aim was to investigate PLA2 activities and characteristics in bronchoalveolar lavage (BAL) fluid, BAL cells, and plasma from patients with ARDS by a fluorometric method. DESIGN: Prospective, controlled study. SETTING: Fourteen-bed polyvalent intensive care unit in a university hospital. PATIENTS: A total of 31 mechanically ventilated patients, 20 with and 11 without ARDS, were studied. INTERVENTION: BAL was performed by fiberoptic bronchoscopy in mechanically ventilated patients with a controlled mechanical ventilation mode. MEASUREMENTS: PLA2 and platelet-activating-factor acetylhydrolase were determined in BAL fluid, cells, and plasma. For the classification of PLA2-specific inhibitors, Western blot analysis and their biochemical characteristics were used. RESULTS: In ARDS patients, increased PLA2 levels were detected in BAL fluid, BAL cells, and plasma compared with the control patients. PLA2 in BAL fluid was mainly type IIA secretory and cytosolic types. In plasma, type IIA secretory and cytosolic and a Ca-independent PLA2 were found. In BAL cells, a cytosolic form, probably a Ca-independent intracellular form, and a low activity of type IIA secretory PLA2 was also observed. Total PLA2 activity correlated inversely with Pao2/Fio2 ratio and positively with the mortality rate. Patients with direct ARDS exhibited higher PLA2 activity compared with patients with indirect ARDS. Platelet-activating-factor acetylhydrolase activity was higher in BAL fluid and plasma, but it was lower in BAL cells. CONCLUSION: Ca-dependent, secretory, cytosolic, and Ca-independent forms of PLA2 and platelet-activating-factor acetylhydrolase could play important roles in the development or down-regulation of inflammation in ARDS, respectively.     

Possible prognostic value of leukotriene B(4) in acute respiratory distress syndrome

OBJECTIVE: To study the major eicosanoids implicated in the pathophysiology of acute respiratory distress syndrome (ARDS) in order to estimate their relative prognostic values. METHODS: We conducted a prospective study in a consecutive series of patients with ARDS admitted to a university hospital intensive care unit. We measured the plasma concentrations of 3 inflammatory mediators (thromboxane B(2), 6-keto prostaglandin F(1alpha), and leukotriene B(4)) in peripheral arterial and mixed venous plasma samples. RESULTS: We studied 16 patients with ARDS, who had a mean alpha SD baseline ratio of P(aO(2)) to fraction of inspired oxygen (P(aO(2))/F(IO(2))) of 147 +/- 37 mm Hg and a mean +/- SD baseline lung injury score of 2.9 +/- 0.37. The plasma concentrations of thromboxane B(2), 6-keto prostaglandin F(1alpha), and leukotriene B(4) were greater than the general-population reference levels in both arterial and mixed venous plasma, but only leukotriene B(4) was higher in arterial plasma than in mixed venous plasma (401 +/- 297 pg/mL vs 316 +/- 206 pg/mL, p = 0.04). When we correlated the eicosanoid concentrations with specific indicators of clinical severity, we found correlations only between the baseline P((aO2))/F(IO(2)) and the arterial thromboxane B(2) level (r = -0.57, p = 0.02), the arterial leukotriene B(4) level (r = -0.59, p = 0.01), and the transpulmonary gradient of leukotriene B(4) level (r = -0.59, p = 0.01). We also found a correlation between the transpulmonary gradient of leukotriene B(4) and the lung injury score (r = 0.51, p = 0.04). The thromboxane B(2) concentration in arterial plasma and the leukotriene B(4) concentration in both arterial and mixed venous plasma were the only baseline plasma eicosanoid concentrations that predicted significant differences in outcome. When looking at the transpulmonary gradient of the eicosanoids studied, we found that only the gradient of leukotriene B(4) showed significant differences of clinical interest. Among survivors we observed practically no gradient (-4.9%), whereas among nonsurvivors we found a substantial positive gradient of 41.6% for the elevated arterial (post-pulmonary) values, compared with the pulmonary-artery (pre-pulmonary) values, and this difference was statistically significant (p = 0.02). CONCLUSIONS: The pro-inflammatory eicosanoid leukotriene B(4) showed the best correlation with lung-injury severity and outcome in patients with ARDS.     

Stimulation of pulmonary big endothelin-1 and endothelin-1 by antithrombin III: a rationale for combined application of antithrombin III and endothelin antagonists in sepsis-related acute respiratory distress syndrome?

OBJECTIVES: Antithrombin (AT) III reduces lung damage in animal models of septic acute respiratory distress syndrome (ARDS), which is generally attributed to stimulation of endothelial prostacyclin synthesis. However, clinical studies have failed so far to demonstrate mortality reduction by application of AT III. We investigated whether AT III stimulates pulmonary prostacyclin release. In addition, we hypothesized that it may promote pulmonary endothelins, thereby mitigating its own protective effect in the course of ARDS. DESIGN: Controlled experiment using isolated organs. SETTING: Experimental laboratory. SUBJECTS: Male Wistar rats. INTERVENTIONS: Isolated lungs were perfused over 120 mins in recirculatory mode in the presence of 50 microg/mL endotoxin (n = 11), 2U/mL AT III (n = 10), 5 U/mL AT III (n = 13), endotoxin plus 2 U/mL AT III (n = 5), or vehicle alone (controls, n = 13), respectively. MEASUREMENTS AND MAIN RESULTS: We determined the effects of AT III on vascular release of thromboxane B2, 6-keto-prostaglandin-F1alpha, big endothelin-1, and endothelin-1. Control lungs released 59+/-23 pg/mL thromboxane B2, 1,480+/-364 pg/mL 6-keto-prostaglandin-F1alpha, 15.2+/-4.5 pg/mL big endothelin-1, and 0.46+/-0.13 pg/mL endothelin-1. Exposure to endotoxin increased thromboxane B2 release 2.9-fold, 6-keto-prostaglandin-F1alpha release 1.6-fold, and endothelin-1 1.6-fold (p < .05 each); levels of big endothelin-1 were unchanged. AT III at 2 U/mL elevated production of big endothelin-1 (1.7-fold) and endothelin-1 (1.2-fold) (p < .05 for both). AT III at 5 U/mL enhanced levels of big endothelin-1 (1.6-fold) and endothelin-1 (1.3-fold) (p < .05 for both). Neither dose of AT III affected thromboxane B2 or 6-keto-prostaglandin-F1alpha concentrations. Application of 2 U/mL AT III plus endotoxin stimulated big endothelin-1 production (2.6-fold) compared with endotoxin or AT III alone (p < .05 for both), but did not further elevate endothelin-1 release. CONCLUSIONS: AT III does not stimulate pulmonary prostacyclin, but promotes pulmonary release of big endothelin-1 and endothelin-1 under basal and, particularly, under septic conditions, which may blunt the AT III-induced lung protection during ARDS. Therefore, we suggest combined application of AT III and endothelin antagonists in animal models of septic ARDS.     

Local abnormalities in coagulation and fibrinolytic pathways predispose to alveolar fibrin deposition in the adult respiratory distress syndrome.

To determine the possible mechanism(s) promoting alveolar fibrin deposition in the adult respiratory distress syndrome (ARDS), we investigated the initiation and regulation of both fibrinolysis and coagulation from patients with ARDS (n = 14), at risk for ARDS (n = 5), and with interstitial lung diseases (ILD) (n = 8), and normal healthy individuals (n = 13). Bronchoalveolar lavage (BAL) extrinsic pathway inhibitor activity was increased in ARDS BAL compared with patients at risk for ARDS (P = 0.0146) or normal controls (P = 0.0013) but tissue factor-factor VII procoagulant activity was significantly increased in ARDS BAL compared with all other groups (P less than 0.001). Fibrinolytic activity was not detectable in BAL of 10 of the 14 patients with ARDS and low levels of activity were found in BAL of the other four ARDS patients. Depressed fibrinolysis in ARDS BAL was not due to local insufficiency of plasminogen; rather, there was inhibition of both plasmin and plasminogen activator. Plasminogen activator inhibitor 1 was variably detected and low levels of plasminogen activator inhibitor 2 were found in two ARDS BAL samples, but plasminogen activator inhibitor 2 was otherwise undetectable. ARDS BAL antiplasmin activity was, in part, due to alpha 2-antiplasmin. We conclude that abnormalities that result in enhanced coagulation and depressed fibrinolysis, thereby predisposing to alveolar fibrin deposition, occur in the alveolar lining fluids from patients with ARDS.