Surfactant treatment of respiratory failure induced by hydrochloric acid aspiration in rats.

BACKGROUND: The surfactant system seems to be involved in the pathophysiology of respiratory failure caused by hydrochloric acid (HCl) aspiration. This study was an investigation of the effect of different treatment strategies using an exogenous surfactant preparation on lung function of rats suffering from respiratory failure after intratracheal HCl instillation. METHODS: In rats anesthetized with halothane, nitrous oxide, and oxygen, tracheotomy was performed and the lungs were mechanically ventilated. Respiratory failure was induced by intratracheal instillation of HCl (0.1 N, 3 ml/kg). After the PaO2 decreased to < 200 mmHg, the animals were randomly divided into five groups. Group I received no treatment; group II received a natural surfactant preparation intratracheally (200 mg/kg); group III underwent bronchoalveolar lavage (BAL) with saline, followed by surfactant treatment (200 mg/kg); and groups IV and V underwent BAL with saline and a diluted surfactant suspension (3.3 mg/ml in 30 ml/kg), respectively. Groups IV and V received a second and third BAL 60 and 120 min after the first lavage. Blood gas analysis and protein measurements in BAL fluids were performed. RESULTS: Gas exchange improved in Groups III and V only. Protein concentrations were high in all BAL fluids. In the rats receiving BAL three times (groups IV and V), a decrease in protein concentration was observed. CONCLUSIONS: From these results, it was concluded that plasma-derived proteins (which are known to inhibit surfactant function) are washed out of the alveoli by BAL, resulting in improved efficacy of surfactant treatment.

Pharmacological model for airway hypersensitivity produced by propranolol and reserpine in guinea pigs.

Combined treatment with propranolol and reserpine enhanced acetylcholine-induced dose-response curves for bronchoconstriction in guinea pigs in vivo. This airway hyperreactivity model was investigated pharmacologically. (1) Increased capillary permeability and increases in leukocytes in bronchoalveolar lavage fluid (BALF) were not observed after this combined treatment. (2) The increased airway sensitivity to acetylcholine produced by propranolol and reserpine was inhibited by ketotifen and theophylline, reported in clinical studies to inhibit airway hyperreactivity. (3) Two leukotriene (LT) receptor antagonists, MCI-826 and FPL-55712, clearly inhibited this increased airway reactivity. (4) A thromboxane A2 (TXA2) receptor antagonist, ONO-3708, and TXA2 synthetase inhibitor, OKY-046, also inhibited this increased airway reactivity. These results suggest that the airway hyperreactivity model produced by propranolol and reserpine in guinea pigs is a valuable pharmacological tool for investigating a remedy and LT and TXA2 may be involved in the onset of this airway hyperreactivity.

Lung function and bronchial responsiveness after bronchoalveolar lavage and bronchial biopsy performed without premedication in stable asthmatic subjects.

We evaluated tolerance, safety, and effects on lung function and bronchial responsiveness of BAL (4 x 50 ml) combined with BB (three to five specimens) performed without premedication in 13 mild and stable asthmatics and eight healthy volunteers. All subjects tolerated bronchoscopy procedures well and without serious side effects. During procedures, no supplemental oxygen was administered and no ECG abnormalities were noted. The PEFR was measured before and immediately after bronchoscopy and at 5-min intervals up until recovery. The maximal percentage fall in PEFR after bronchoscopy was significantly greater in asthmatics (23.1 +/- 13.9 percent) compared to normal subjects (7.8 +/- 8.2 percent, p less than 0.01). Changes in PEFR returned to baseline values within 120 min in all asthmatics. The tcPO2 was recorded at baseline, during and after bronchoscopy. In both groups, a significant change in tcPO2 was measured during the infusion of BAL aliquots, and persisted throughout the procedure. A significant difference in asthmatics compared to healthy subjects was evident during BB and at the end of the procedure (p less than 0.05). In asthmatics, M challenge was performed on three different days over a three-week period prior to bronchoscopy, and was repeated at intervals of 2, 6, and 24 h following procedure. The PC20 M values measured before bronchoscopy were found to have a very high reproducibility (intraclass correlation coefficient = 0.93). The PC20 values measured during experiment times after bronchoscopy were not significantly different from baseline values. These data demonstrate that in mild and stable asthmatics, BAL combined with BB can be safely performed following administration of only local anesthesia. In carefully selected asthmatic subjects, transient bronchoconstriction and a lowering of oxygen tension can be induced by BAL and BB, whereas changes in bronchial responsiveness are more unlikely to occur.

Daño pulmonar experimental por bleomicina en ratas: alteraciones del lavado broncoalveolar e histopatología / Experimental pulmonary damage by bleomycin in rats: changes in bronchoalveolar lavage and histopathology

Estudios previos han demostrado que la instilación endotraquial de bleomicina en la rata produce edema e inflamación al cabo de 24H y cierto grado de fibrosis luego de 15 días. El objetivo de este trabajo fue evaluar el daño pulmonar inducido a largo plazo (3,7,14,30 y 60 días)por la instilación endotraqueal de 1U de bleomicina por 100g de peso a fin de relacionar las alteraciones del lavado broncoalveolar (LBA) conla histopatología pulmonar. La serie control consistió en ratas instiladas con NaCl 0,9 por ciento vía endotraqueal y sometidas a similares procedimientos. En el LBA se practicó recuento celular y determinaciones de proteínas, fosfolípidos, fosfatasa alcalina gama glutamiltranspeptidasa (GGT). Se observó aumento significativo (p<0,05)de la realción peso pulmonar/peso corporal en las ratas tratadas con bleomicina la histología reveló daño pulmonar temprano (3 a 7 días):aumento de neutrófilos y eosinófilos y hemorragia intra-alveolar. En días ulteriores (14 a 60 días) se observó pérdida de la arquitectura, proliferación de neumocitos tipo II y fibrosis pulmonar. En el LBA de las ratas tratadas con bleomicina se observó aumento significativo (p<0,05)en realción a la serie de control en las siguientes variables: células (3 y 14 días), proteínas (3-7 y 30 días), fosfolípidos, fosfatasa alcalina y GGT (7-14 y 30 días). En el daño pulmonar pr bleomicina existiría relación entre el grado de inflamación de la fase exudativa y las alteraciones del LBA. La determinación de fosfatasa alcalina y GGT en el LBA podría ser potencialmente útil en el seguimiento del daño pulmonar por bleomicina

[Mechanisms of pulmonary fibrosis]. / Mécanismes de la fibrose pulmonaire.

Lung fibrosis is characterized by the accumulation of extracellular matrix and mesenchymal cells leading a progressive loss of respiratory functional units. The accumulation of mesenchymal cells results from their migration and local replication. These cellular events are dependent upon the local presence of cytokines with chemotactic and/or mitogenic activity. The sequence of events leading the lung fibrosis is thought to result from a stereotyped response: after an initial injury, an inflammatory reaction develops and controls tissue repair through local production of cytokines. The permanency of these processes results in the development of fibrosis.

[Value of bronchoalveolar lavage in the diagnosis and management of diffuse interstitial fibrosing lung diseases]. / Intérêt du lavage broncho-alvéolaire dans le diagnostic et la prise en charge des pneumopathies interstitielles diffuses fibrosantes.

Bronchoalveolar lavage (BAL) is an exploratory technique which is easy to perform and collect cellular constituents, notably inflammatory and immunocompetent cells, as well as biological elements that are present in the distal airways. In patient with chronic diffuse infiltrative lung disease, analysis of these parameters reveals various disturbances such as neutrophilia frequently associated with eosinophilia and, in some cases, lymphocytosis. These features are not specific, but they differentiate chronic diffuse infiltrative lung diseases from sarcoidosis and hypersensitivity lung diseases. Alveolar inflammation (alveolitis) correlates with the evolutive potential of the lesions and their ability to respond to treatment. The presence of lymphocytosis is usually associated with response to corticosteroid therapy, whereas the presence or persistence of neutrophilia and, even more, eosinophilia is characteristic of patients who do not respond to corticosteroids but are amenable to the cyclophosphamide-corticosteroid combination. BAL therefore increasingly appears as an irreplaceable tool to understand the physiopathology of chronic diffuse infiltrative lung diseases.

Bronchoalveolar lavage: comparison of three commonly used procedures.

We have studied three different lavage procedures (100, 200 and 300 ml) in patients with pulmonary sarcoidosis (stage I). The effect of bronchoalveolar lavage (BAL) on cell yield, lavage fluid recovery, dwelling time, lavage-induced arterial oxygen desaturation and occurrence of side effects was analyzed. The patients did not differ significantly in prelavage lung function and blood gas parameters. The lowest BAL return was seen in the 300-ml lavage procedure (49.5%), while the medium yielded over 70%. The lowest cell yield was seen in the BAL 100 group (10.4 X 10(6)); the highest in the BAL 300 (19.4 X 10(6)), but the latter did not differ significantly from BAL 200 (18.4 X 10(6)). Dwelling time of the fluid differed only slightly between the small and middle volume lavage (average 3.2 vs. 3.9 min p less than 0.01), but was significantly lower from the average dwelling time in the BAL 300 group (9.8 min, p less than 0.001). Arterial oxygen desaturation was lowest in the BAL 100 and most pronounced in the large-volume lavage. Side effects were seen in all but 1 patient undergoing BAL 300. Cough was the most often reported side effect (9 patients); fever was observed in 6 patients, dyspnea in 4 (all undergoing large-volume lavage). Considering our results we do not think that it is justifiable to increase the volume of instilled fluid above 200 ml, because this may lead to serious side effects without increasing benefits. Using lower than 200 ml volumes decrease diagnostic yield although the risk of developing side effects is much lower.

Cytotoxic factor for fibroblasts in bronchoalveolar lavage fluid of bleomycin-treated rats.

The mechanisms of lung injury and fibrosis in diffuse interstitial lung diseases were studied by tests on the in vitro effect of bronchoalveolar lavage fluid (BALF) from bleomycin-treated rats on quiescent fibroblasts in culture. The BALF was obtained on days 2, 3, 6, 15, and 29 after intratracheal administration of bleomycin. Cytotoxic activity was detected in the BALF only on day 2. The factor responsible for the cytotoxic activity was detected in 50-70% ammonium sulfate fraction, and lost 10% of its activity after 30 min at 56 degrees C, 75% after 10 min at 80 degrees C, and all activity after 10 min at 100 degrees C. The factor was completely precipitated by 60% acetone and was not extractable with ether. In ion exchange chromatography, the factor was eluted with the main fraction of protein, and gel filtration indicated that it had a molecular weight of 60-70 kDa. Histological examination showed disappearance of the normal alveolar architecture on day 2, and pulmonary fibrosis on day 15. Thus the cytotoxic factor may be one of factors responsible for lung injury and may act as trigger for subsequent fibrosis in bleomycin-induced lung damage.

[Theoretical basis and clinical assessment of fluid evacuation from the lungs during bronchoalveolar lavage in children]. / Teoreticheskoe obosnovanie i klinicheskaia otsenka évakuatsii zhidkosti iz legkikh pri bronkhoal'veoliarnom lavazhe u detei.

The authors discuss the theoretical aspects of the process of lavage fluid absorption from bronchial and alveolar spaces during broncho-alveolar lavage. It is shown that pressure in the vessels of pulmonary circulation, the blood colloid osmotic pressure, and permeability of the alveolar-capillary barrier play an important role in the dynamics of changes of the absorption process. Methods for correcting the intensity of absorption (use of solutions of different osmotic force for lavage) are suggested. Data gained in observation over the use of therapeutic lavage in children confirm the theoretical conclusions and demonstrate the favourable results of lavage in children with atelectases.

Tumor necrosis factor alpha-induced pulmonary vascular endothelial injury.

Tumor necrosis factor alpha (TNF-alpha) mediates components of the acute-phase response, stimulates granulocyte metabolism, and induces endothelial cell surface changes. We studied whether human recombinant TNF-alpha (rTNF-alpha) could increase pulmonary edema formation and pulmonary vascular permeability. Rabbits preinfused with 125I-albumin were administered rTNF-alpha or saline. Animals were sacrificed, and lung wet/dry weight ratios as well as bronchoalveolar lavage fluid and plasma 125I activities were determined. rTNF-alpha increased lung wet/dry weight ratios by 151% (P less than 0.02) and bronchoalveolar lavage fluid/plasma 125I activity ratios by 376% (P less than 0.01) compared with values for saline controls. Electron microscopy of lung sections demonstrated endothelial injury, perivascular edema, and extravasation of an ultrastructural permeability tracer. To demonstrate that rTNF-alpha could directly increase pulmonary vascular endothelial permeability in vitro, we studied albumin transfer across cultured porcine pulmonary artery endothelial cell monolayers. rTNF-alpha induced time-dependent dose-response increments in transendothelial albumin flux in the absence of granulocyte effector cells. These observations suggest that rTNF-alpha can provoke acute pulmonary vascular endothelial injury in vivo as well as in vitro.

Impaired antipneumococcal activity of bronchoalveolar lining material of neonatal rats.

Pulmonary clearance of inhaled pneumococci is markedly impaired in neonatal rats compared with that in adult rats. To determine whether this impairment is due to a deficiency of extracellular bactericidal factors, the antipneumococcal activity of free fatty acids (FFA) in lung surfactant and the levels of lysozyme and transferrin in lavage fluids were quantified. Surfactant from adult rats averaged 68 U of antipneumococcal activity per g (dry weight) of lung, compared with less than 0.25 U for rats less than 1 week old (P less than 0.001). The kinds of FFA in surfactant of neonatal and adult rats were essentially identical, and the antipneumococcal activity of highly purified FFA from surfactant of neonatal and adult rats was also the same. However, the quantity of FFA in surfactant varied significantly with age, and rats less than 3 weeks old had much lower levels of surfactant FFA than did adults (P less than 0.001). In addition, lavage fluids from neonatal rats inhibited the antipneumococcal activity of surfactant FFA more than lavage fluids from adults did (P less than 0.02). This inhibitory activity did not appear to be due to protein binding. Lavage fluids from neonates showed an age-related deficiency of lysozyme (P less than 0.001), but lysozyme appeared to play no role in pneumococcal killing by the surfactant fraction of lavage fluids in vitro. Transferrin levels in lavage fluids were similar for neonates and adults. It was concluded that lung surfactant from neonatal rats was deficient in antipneumococcal activity, due mostly to low levels of FFA and to a lesser degree to increased levels of inhibitor(s) in lavage fluids.

Prolonged exposure of neutrophils to saline or bronchoalveolar lavage fluid does not alter superoxide anion generation.

The role played by neutrophils (PMNs) in the genesis of lung injury in diverse clinical situations, such as bronchial asthma, idiopathic pulmonary fibrosis, and the adult respiratory distress syndrome, is an area of intensive investigation. Functional studies of PMNs, particularly those obtained from the alveoli by bronchoalveolar lavage, should shed light on their contribution to lung injury. However, it has not been demonstrated whether procedures used to harvest cells from the lung (bronchoalveolar lavage), particularly the potentially prolonged exposure to saline, commonly used to perform lavage, and other components of lavage fluid, can alter the functional characteristics of PMNs. In this report we demonstrate that a 2- to 3-hour exposure of neutrophils to saline from both humans and sheep in vitro does not alter the functional characteristics of PMNs as determined by superoxide anion generation after activation with phorbol myristate acetate (PMA; 6.96 +/- 0.44 vs. 7.60 +/- 0.32 nmol O2-/250,000 PMNs for control and saline-treated human cells, respectively, after a 45-min incubation with 10(-7) M PMA, and 4.73 +/- 0.30 vs. 4.50 +/- 0.42 nmol O2-/250,000 PMNs for control and saline-treated sheep cells). In a second series of experiments, we studied the effect of exposure of human PMNs to bronchoalveolar lavage fluid supernatants obtained from normal volunteers on superoxide anion generation by neutrophils.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Local abnormalities of coagulation and fibrinolysis and alveolar fibrin deposition in sheep with oleic acid-induced lung injury.

Extravascular, primarily intra-alveolar, fibrin deposition is a histologic hallmark of acute lung injury in humans and experimental animals, but the mechanisms leading to this finding are poorly understood. To determine whether local abnormalities in the fibrinolytic-procoagulant balance contribute to alveolar fibrin deposition in acute lung injury, we studied bronchoalveolar lavage (BAL) fluids of anesthetized sheep that received intravenous oleic acid. Prominent alveolar fibrin deposition was observed within 2 h after oleic acid-induced lung injury. Procoagulant and fibrinolytic activities were determined in BAL samples of anesthetized, mechanically ventilated sheep before and 2 h after intravenous oleic acid or saline. BAL procoagulant activity was found to be due mainly to tissue factor associated with Factor VII. In baseline BAL samples, we found relatively low levels of procoagulant activity and relatively high levels of fibrinolytic activity. After induction of oleic acid-induced lung injury, the procoagulant activity of BAL was markedly increased, whereas fibrinolytic activity was either depressed or undetectable. Antiplasmin activity was detectable in BAL of sheep after oleic acid-induced lung injury, which contributed at least in part to the depressed fibrinolytic activity observed. These perturbations occurred with the appearance of extensive alveolar fibrin deposition. In control sheep, BAL fibrinolytic activity was decreased, and antiplasmin activity increased modestly after 2 h of mechanical ventilation, but procoagulant activity was unchanged and alveolar fibrin was not observed. Procoagulant activity in lung lymph and plasma after lung injury did not differ from baseline values, and fibrinolytic activity was undetectable in lymph or plasma samples. These data indicate that increased procoagulant activity and concurrent disruption of the balance of coagulation and fibrinolysis establish local conditions that promote acute fibrin deposition in the alveoli of mechanically ventilated, oleic acid-injured sheep.

The effect of bronchoalveolar lavage on bronchial responsiveness in patients with airflow obstruction.

This study assessed the effect of bronchoalveolar lavage (BAL) on nonspecific bronchial responsiveness in 31 patients. Of these, 20 had airflow obstruction; 11 control subjects had normal pulmonary function. Bronchial responsiveness to methacholine, expressed as the dose of inhaled methacholine required to provoke a 20 percent fall in forced expiratory volume in one second (PD20 FEV1), was measured before and after BAL. We found no evidence for the induction of responsiveness by BAL in 11 control subjects with negative methacholine tests prior to the procedure. There were small but significant falls in FEV1 following BAL in both the control group and in patients with airflow obstruction. Thus, BAL does not appear to induce nonspecific bronchial hyperresponsiveness in subjects without airflow obstruction, nor does it affect airway responsiveness in emphysema patients. Among asthmatics, bronchial responsiveness can be increased as a result of BAL; this increase was greatest in patients who were most responsive initially.

Hyaluronate in bronchoalveolar lavage fluid in sarcoidosis and its relationship to alveolar cell populations.

Hyaluronate is a potential marker of activated pulmonary fibroblasts and appears in increased amounts in bronchoalveolar lavage fluid from patients with sarcoidosis. This study was performed to investigate a possible link between the local immune response and pulmonary fibroblast proliferation. The median hyaluronate concentration in the lavage fluid from 23 sarcoid patients was 12.0 (interquartile range 7.5-28.5) micrograms/l. The hyaluronate concentration was positively correlated to the concentration and proportion of lymphocytes (p less than 0.001 and p less than 0.01, respectively) as well as to the concentrations of T lymphocyte subsets (OKT4+ p less than 0.01, OKT8+ p less than 0.05). No correlation was found between the hyaluronate concentration and the OKT4+/OKT8+ ratio. Furthermore, a significant correlation was observed in the lavage fluid between hyaluronate and angiotensin-converting enzyme, a marker of monocyte/macrophage activity (p less than 0.01). Thus, the intensity of the sarcoid alveolitis was associated with biochemical signs of pulmonary fibroblast proliferation/activation in sarcoidosis.