Bronchoalveolar lavage

Aspiration techniques for bronchoalveolar lavage in translational respiratory research: Paving the way to develop novel therapeutic moieties

Bronchoalveolar lavage (BAL) is a simple, yet informative tool in understanding the immunopathology of various lung diseases via quantifying various inflammatory cells, cytokines and growth factors. At present, this traditional method is often blended with several robust and sophisticated molecular and biological techniques sustaining the significance and longevity of this technique. Crucially, the existence of slightly distinct approaches and variables employed at different laboratories around the globe in performing BAL aspiration indeed demands an utmost need to optimize and develop an effective, cost-effective and a reproducible technique. This mini review will be of importance to the biological translational scientist, particularly respiratory researchers in understanding the fundamentals and approaches to apply and consider with BAL aspiration techniques. This will ensure generating a meaningful and clinically relevant data which in turn accelerate the development of new and effective therapeutic moieties for major respiratory conditions.

Bronchoalveolar Lavage of Murine Lungs to Analyze Inflammatory Cell Infiltration

Bronchoalveolar Lavage (BAL) is an experimental procedure that is used to examine the cellular and acellular content of the lung lumen ex vivo to gain insight into an ongoing disease state. Here, a simple and efficient method is described to perform BAL on murine lungs without the need of special tools or equipment. BAL fluid is isolated by inserting a catheter in the trachea of terminally anesthetized mice, through which a saline solution is instilled into the bronchioles. The instilled fluid is gently retracted to maximize BAL fluid retrieval and to minimize shearing forces. This technique allows the viability, function, and structure of cells within the airways and BAL fluid to be preserved. Numerous techniques may be applied to gain further understanding of the disease state of the lung. Here, a commonly used technique for the identification and enumeration of different types of immune cells is described, where flow cytometry is combined with a select panel of fluorescently labeled cell surface-specific markers. The BAL procedure presented here can also be used to analyze infectious agents, fluid constituents, or inhaled particles within murine lungs.

Standardization of bronchoalveolar lavage method based on suction frequency number and lavage fraction number using rats

Bronchoalveolar lavage (BAL) is a useful tool in researches and in clinical medicine of lung diseases because the BAL fluid contains biochemical and cytological indicators of the cellular response to infection, drugs, or toxicants. However, the variability among laboratories regarding the technique and the processing of the BAL material limits clinical research. The aim of this study was to determine the suction frequency and lavage fraction number necessary to reduce the variability in lavage using male Sprague-Dawley rats. We compared the total cell number and protein level of each lavage fraction and concluded that more cells and protein can be obtained by repetitive lavage with a suction frequency of 2 or 3 than by lavage with a single suction. On the basis of total cell recovery, approximately 70% of cells were obtained from fractions 1~3. The first lavage fraction should be used for evaluation of protein concentration because fractions 2~5 of lavage fluid were diluted in manifolds. These observations were confirmed in bleomycin-induced inflamed lungs of rats. We further compared the BAL data from the whole lobes with data from the right lobes and concluded that BAL data of the right lobes represented data of the whole lobes. However, this conclusion can only be applied to general lung diseases. At the end, this study provides an insight into the technical or analytical problems of lavage study in vivo.

Diagnóstico citológico de neoplasia pulmonar por meio de lavado broncoalveolar em uma cadela: relato de caso

Relata-se o caso de uma cadela de raça Poodle, de 12 anos de idade, com quadro clínico de tosse crônica não responsiva à terapia medicamentosa. O exame radiográfico mostrou imagem de consolidação do lobo pulmonar esquerdo. O exame de lavado broncoalveolar pelo broncofibroscópio mostrou células epiteliais com características de malignidade, permitindo firmar o diagnóstico de carcinoma pulmonar sem diferenciação entre neoplasia primária ou metastática.

Cytologic evaluation of the respiratory tract

Evaluation of respiratory tract disease is a challenge for several reasons: no serum biochemical or hematologic tests that localize injury to the respiratory system are available, imaging techniques do not usually lead to etiologic diagnoses, and excisional biopsies are often very difficult to obtain from respiratory lesions. For these reasons, specific diagnosis of respiratory tract disease often resides in cytologic evaluation. This article reviews the various cytologic collection techniques that yield high-quality specimens from the upper and lower respiratory tract. Cytologic features of the normal respiratory tract as well as common respiratory disorders are described and illustrated.

Role of chronic Pseudomonas aeruginosa infection in airway mucosal permeability

The role of Pseudomonas aeruginosa infection in airway mucosal permeability was studied in 16 patients with chronic bronchitis by measuring the amounts of radiolabeled albumin in sputum. One group (A) consisted of six patients (two female, four male, 53 +/- 6 years, SEM) with chronic P aeruginosa infection for 5 +/- 0.9 years. Another group (B) consisted of ten patients (five female, five male, 67 +/- 4 years) without P aeruginosa infection for at least two years. No significant differences between groups A and B were found in the volume of sputum (63 +/- 21 ml/day in group A and 45 +/- 8 ml/day in group B, p = 0.44), the obstructive changes (FEV1 of 57 +/- 6 percent in group A and 51 +/- 4 percent in group B), or the duration of disease (19 +/- 4 years in group A and 14 +/- 4 years in group B). Saliva, sputum, and serum samples were collected at intervals of 2 h over an 8-h period, and at 24 h after intravenous administration of 131I-labeled human albumin. For counting, free 131I was removed by dialysis. Radiocounts (cpm) of saliva were significantly smaller than those of sputum or serum. The cpm from each sputum sample was divided by serum cpm at the time of each sampling. Group A showed significantly higher values in the ratio of sputum- to serum-cpm than did group B at all sampling times. Furthermore, the ratios at 2 and 4 h after 131I-albumin injection significantly correlated with sputum volume per day, whereas they did not correlate with any other factors (age, obstructive impairment, and duration of disease). These findings suggest that chronic P aeruginosa infection produces an increase in airway mucosal permeability to albumin.

Performance and prognosis in patients with lung cancer. The Edinburgh Lung Cancer Group

The Edinburgh Lung Cancer Group prospectively registered 651 new patients presenting with lung cancer during 1981; only 47 survived five years (7%). The survival rate was highest in patients selected for surgery (35/116, 30%) and in this group was related to cell type, stage of disease, and possibly to Karnofsky performance score (not statistically significant). By comparison with non-surgical patients these 116 patients undergoing surgery were highly selected in terms of age, favourable histological type, stage of disease, and performance score. Forty-two of the 535 non-surgical patients were given radical radiotherapy alone and seven (17%) survived five years. The remaining 493 received palliative radiotherapy, chemotherapy (alone or combined with radiotherapy), or symptomatic treatment alone; only five (1%) survived five years. Median survival was related to cell type (adenocarcinoma 2.6 months, squamous cell carcinoma 6.2 months), stage (stage I 8.5 months, stage III 4 months), and Karnofsky performance index (greater than or equal to 90 9.3 months, less than or equal to 50 1.2 months). Age and sex had no independent prognostic value in any group. Performance score was highly correlated with stage (and age) and in this study represented the "best prognostic factor" in clinical practice.

Future directions for bronchoalveolar lavage

Bronchoalveolar lavage provides a means to sample the lung. The ability to describe material obtained from the lower respiratory tract has greatly facilitated pulmonary diagnosis, and it is likely that improvements in diagnostic techniques will continue to develop. The ability to accurately measure lower respiratory tract components has permitted staging of lung disease. Such staging will probably provide improved prognostic insight and permit the development of new therapeutic strategies in lung disease.

Measures of the inflammatory response in cryptogenic fibrosing alveolitis

Cryptogenic fibrosing alveolitis (CFA) is characterized by interstitial fibrosis and parenchymal inflammation. Eleven patients with CFA (10 proved by lung biopsy) were followed over 2 yr using clinical symptoms, radiographic change, and pulmonary function tests to adjust their treatment. Lung lavage, positron camera (PET) measurements of regional extravascular lung density (Dev), pulmonary blood volume (Vb), and the metabolic rate for 18F-deoxyglucose (MRglc), clearance of 99mTc-diethylenetriaminepentacetate (99mTc-DTPA) aerosol, and lung uptake of 67Ga were measured initially and at the end of the first year to give a profile of the inflammatory response. Compared with normal subjects, there was an increased percentage of neutrophils and eosinophils in the lung lavage, increased Dev (p less than 0.002) with no significant difference in Vb, increased MRglc (p less than 0.02), 99mTc-DTPA clearance (p less than 0.002), and 67Ga uptake (p less than 0.02). The smallest increases in Dev were seen in the two patients with most destruction shown by lung biopsy. There were inverse correlations between Dev and both FVC and TLC, but a direct correlation between Vb and transfer factor. 99mTc-DTPA clearance changed concordantly with clinical status and radiographic and respiratory function changes during the first year. If glucose utilization (MRglc) remained in the normal range between the initial and first yearly assessment, the patient improved or remained stable during the second year as shown by clinical status and radiographic and respiratory function measurements. If it rose or remained high, the patient's condition deteriorated.(ABSTRACT TRUNCATED AT 250 WORDS)

A sensitive method to detect synthesis of the functional classical, alternative and terminal pathway of complement by cells cultured in vitro

A new method used to study in vitro synthesis by human monocytes and alveolar macrophages of the essential complement components for the functional classical, alternative and terminal pathway is presented. The method is based on accumulation of major complements components on activators of the alternative (agarose beads) and classical (lgM-sensitized sheep erythrocytes; ElgM) pathway during co-culture with the phagocytes. There was a time-dependent increase in binding of labelled protein to the co-cultured activators, demonstrating de novo protein synthesis by the phagocytes. Moreover, there was a significant binding to the co-cultured agarose beads and ElgM of monoclonal anti-C3c, anti-C3g, polyclonal anti-C5-C9 and of two monoclonal antibodies (poly C9-MA and MCaEll) to a neoantigen of polymerized C9 present in the terminal complement complex (TCC). In addition, we found a significant binding of polyclonal anti-C4 antibodies to co-cultured ElgM. Incubation of the activators in human serum, subsequently revealed the same pattern of antibody binding. There was no binding of anti-S protein antibodies to the activators after incubation with serum or with the phagocytes. We thus conclude that mononuclear phagocyte-produced complement in the form of C3b, iC3b, and the TCC (C5b-9) was deposited on both activators, whereas C4b was detected on the ElgM. It is our hope that this method can be applied when studying complement biosynthesis by cells other than mononuclear phagocytes.

Proton magnetic resonance imaging to stage activity of interstitial lung disease

Patients with active interstitial lung disease (ILD) are often treated with high-dose corticosteroids, although such therapy is not universally effective and has significant risks. Clinicians have utilized various ancillary diagnostic techniques to help with difficult treatment decisions. Since magnetic resonance imaging (MRI) has the theoretic and experimental potential of differentiating various stages of ILD, we prospectively studied 34 adult patients in a 0.15 Tesla resistive magnet body imager. The most severely affected patients, who were thought to warrant a steroid trial, had the greatest MRI image intensity, and dramatic improvement was seen following successful treatment. Qualitative MRI data were as useful as any other ancillary diagnostic technique (radiographic, physiologic, scintigraphic) in predicting clinical course. Computer-generated relaxation times were not sufficiently precise to differentiate active from inactive disease. Although limited by availability and cost, MRI appears to be a useful ancillary diagnostic technique in ILD patients facing immunomodulating therapy.

Association of lipid-laden alveolar macrophages and gastroesophageal reflux in children

The association of lipid-laden alveolar macrophages (LLAM) and gastroesophageal reflux (GER) was investigated prospectively in 115 patients in two groups. Group 1 included 74 children with chronic respiratory tract disorders and documented GER by prolonged esophageal pH monitoring, barium esophagram, and esophagoscopy; group 2 included 41 children with chronic respiratory tract disorders without GER. LLAM were present in 63 (85%) and eight (19%) children from groups 1 and 2, respectively (P less than 0.0001). Thus a strong association between the presence of LLAM and GER in children with chronic respiratory tract disorders was established. We suggest that LLAM from bronchial lavage may be a useful marker for tracheal aspiration in children with GER in whom chronic lung disease may subsequently develop.

Ultrastructure of extrinsic allergic bronchiolo-alveolitis

Electron microscopic findings in open lung biopsies of 13 patients with extrinsic allergic bronchiolo-alveolitis (EABA) were studied. Eleven of the patients had farmer's lung and two had been exposed to other mouldy dust. Numerous lymphocytes, macrophages and giant cells were found both in the alveolar and bronchiolar lumina. Bronchiolar changes included loss of microvilli on the ciliated cells, granulomas, detachment of basal cells from each other, as well as disintegration of the basement membrane. In the alveoles hyperplasia and hypertrophy of type II (granular) pneumocytes often loosely connected with the basement membrane, were frequently demonstrated. Disintegration of the basement membrane accompanied by detachment of the pneumocytes occurred occasionally. In the interstitium lymphocytes, mast cells and plasma cells predominated. The size and shape of lymphocytes were variable. In addition, some lymphocytes with pseudopods were detected both in alveolar lumen and in the interstitium. Mast cells were found in close connection with plasma cells occasionally. Granulomas consisting of these cells and giant cells were usually present. Foreign material resembling hyphal fragments was found in the giant cells of two patients. The present series emphasizes the role of lymphocytes, macrophages, giant cells and mast cells, in the pathogenesis of EABA. The presence of numerous plasma cells in the lung parenchyma suggests the possibility of local antibody response caused by exposure to inhaled antigens.

Changes in lipids of lung lavage in monkeys after chronic exposure to ambient levels of ozone

A group of 8 sub-adult bonnet monkeys (Macaca radiata) was exposed to 0.3 ppm ozone (O3) and another group of 7 monkeys to 0.15 ppm O3 for 8 h/day for 90 days. A third group of 4 monkeys was exposed to 0.15 ppm O3 for 8 h/day for 21 days. The control group consisted of 7 monkeys which breathed filtered air for 90 days. Levels of linoleic and arachidonic acids in the total lipids from lung lavage increased about 2-fold in those exposed to O3 as compared to the levels in the controls. Furthermore, the relative level of cholesterol ester (CE) decreased and phosphatidylcholine (PC) increased markedly with chronic exposure of animals to O3. Enhanced polyunsaturated fatty acid (PUFA) composition in lung lavage and changes in the levels of CE and PC may be related to animals' adaptation to O3-exposure.

Asbestosis. Bronchoalveolar lavage fluid proteins and their relationship to pulmonary epithelial permeability

We measured levels of albumin and immunoglobulins in serum and bronchoalveolar lavage (BAL) fluid in 28 men with asbestosis and 11 control subjects. The half-time clearance of inhaled diethylene triamine pentacetate labelled with technetium-99m (99mTc-DTPA) from the lungs (t1/2LB) was measured in 26 patients with asbestosis and in 31 normal nonsmoking controls. In those individuals in whom immunoglobulins were detected in BAL fluid, the mean IgG:albumin ratio in BAL fluid was 0.30 (range, 0.11 to 0.97), significantly less than the ratio of 0.43 (0.28 to 0.66) in control subjects (p less than 0.05). There was no significant difference in IgA:albumin ratios between patients and control subjects. The mean BAL:serum albumin ratio in patients with asbestosis was 2.3 X 10(-3) (range, 0.2 to 9.5 X 10(-3), significantly greater than the ratio of 1.2 X 10(-3) (0.5 to 2.0 X 10(-3] in control subjects (p less than 0.02). The t1/2LB was significantly shorter in both smokers and nonsmokers with asbestosis, compared with 31 normal nonsmoking controls, but there were no relationships between t1/2LB and BAL:serum albumin ratio or any other BAL protein levels in either smokers or nonsmokers with asbestosis.

Immunohistological analysis of lung tissue from patients with cryptogenic fibrosing alveolitis suggesting local expression of immune hypersensitivity

Immunohistological analysis using monoclonal antibodies in conjunction with histochemical techniques has been applied to lung biopsy material from patients with cryptogenic fibrosing alveolitis. Subsets of lymphoid and non-lymphoid cells have been identified in situ. This analysis showed that the inflammatory cells present were predominantly mononuclear. Most of the lymphoid cells were B lymphocytes, organised into follicles with occasional germinal centre formation. IgM was the major class of immunoglobulin expressed. Both T4+ and T8+ lymphocytes were seen diffusely distributed in the interstitium. The T4+ positive cells were also seen within the B lymphoid follicles. Almost all non-lymphoid cells expressed the phenotype of inflammatory macrophages, but a few also expressed a phenotype characteristic of interdigitating cells. These results suggest that a local B lymphoid immune response is occurring in cryptogenic fibrosing alveolitis. The possibility that a cell mediated immune response is also emerging is discussed.

Assessment of drug disposition in the lung

Airway disposition of drugs is assessed with either physiological changes in lung mechanics or nuclear scanning of the tagged medication. Several methods have been described for assessment of the pulmonary disposition of drugs delivered by routes other than the airways. These methods include tissue biopsy and sputum analysis of pooled secretions and tracheal washings. More recently, bronchoalveolar lavage fluid has been analysed for a variety of pharmacological agents and comparisons drawn between blood and lavage supernatant levels. Problems in correcting for dilution have been overcome by using a naturally occurring tracer substance, such as creatinine or albumin, which has a similar molecular weight to the test chemicals and which can be assayed readily in blood and lavage fluid. It has become apparent that neither naturally occurring not exogenous chemicals enter the lung in a concentration that is predictable from their levels in the blood. While the alpha 2-macroglobulin level in lavage fluid is approximately 25 times less than that in serum, a 1:1 relationship exists for alpha 1-antitrypsin. Cortisol achieves a concentration in lung fluid equal to that of blood, but lung fluid concentrations of methylprednisolone and prednisone are one-half, or at best one-third, of the blood concentration, respectively. Knowledge regarding the penetration of antibiotics into the lung is useful in determining the potential effectiveness of a given agent and its likely acinar MIC. It appears that the alveolar-capillary unit is not freely permeable to all agents, raising the possibility that a blood-lung barrier exists which is responsible for maintaining the alveolar environment. The knowledge that there is a differential permeability among drugs makes it important for clinicians to assess this characteristic of each agent before conclusions linking dose and response are drawn.

Assessment of progression of asbestosis in the sheep model by bronchoalveolar lavage and pulmonary function tests

To study the relationship between the results of bronchoalveolar lavage and pulmonary function tests during induction and progression of asbestosis, three groups of six sheep were exposed repeatedly by intratracheal injection to either saline (controls), low doses of Canadian chrysotile UICC asbestos (cumulative exposure 328 mg) (low-dose group), or high doses of the same fibres (cumulative dose 2282 mg) (high-dose group) until there was clear evidence of alveolitis from the lung biopsy specimens of all sheep of the high-dose group. During the course of this induction and for the following eight months lung biopsies, bronchoalveolar lavage and pulmonary function tests were performed at two-month intervals. At the time of initial alveolitis in the high-dose group there was no significant change in the cellularity of the bronchoalveolar lavage fluid, but static lung compliance (Cst), vital capacity (VC), arterial oxygen tension (Pao2), and diffusion capacity (DL/VA) were significantly lower than in the other groups. In the following months, as the alveolitis evolved into a fibrosing process, macrophages and neutrophils from the bronchoalveolar lavage fluid increased significantly and pulmonary function deteriorated. Proteins and enzymes in the bronchoalveolar lavage fluid also increased significantly in the high-dose group. These data show that in the sheep model of asbestosis simple tests of pulmonary function correlate well with histological changes and changes in the bronchoalveolar lavage fluid in the course of the disease and can be used to assess progression of asbestosis.

Plasminogen activator and thromboplastin activity from sheep alveolar macrophages

Alveolar lavage cells from normal sheep were found to be composed of over 95% macrophages. When the cells were cultured, fibrinolytic and thromboplastin-like activities could be detected within 2-4 hours of incubation. As the number of cultured cells was increased the two activities in the conditioned medium increased proportionately. The cells were separated into two distinct subpopulations by means of a sedimentation velocity cell fractionation technique. The macrophage subpopulations were examined for differences in size, morphology, esterase staining and ability to release plasminogen activator and procoagulant activity respectively. These activities were confined to the large cell subpopulation. The fibrinolytic activity was shown to be plasminogen-dependent and could be inhibited by DFP. On the basis of this the fibrinolytic activity has been designated as plasminogen activator. The procoagulant activity was shown to be thromboplastin in nature because it was Factor VII dependent, inactivated by phospholipase C and not inhibited by DFP. The procoagulant activity has been designated as macrophage thromboplastin. The two activities could be distinguished on the basis of DFP inhibition.

Arterial PCO2 as an index of activity in fibrosing alveolitis

Alveolar hyperventilation is a characteristic feature of the interstitial lung diseases, yet its pathogenesis remains unknown. We examined the relationship between inflammatory alveolar acinar cell counts and the steady state, resting arterial PCO2 in patients with fibrosing alveolitis. To eliminate the influence of overwhelming mechanical lung restriction or resting hypoxemia, we studied 20 patients who, despite having clinicopathologically confirmed fibrosing alveolitis, had vital capacities exceeding 50 percent of predicted, and arterial O2 saturations above 90 percent. There was a significant inverse relationship between the proportion of polymorphonuclear leukocytes (PMNs) in the recovered BAL fluid and the arterial PCO2 (r = -0.67; p less than 0.01). When PCO2 was above 35 mm Hg, the BAL PMN count was 8 percent or less (mean = 3.4; SD = 2.5), while the mean BAL PMN count among those patients whose PCO2 was less than 35 mm Hg was significantly higher (mean = 11.7; SD = 3.7; p less than 0.01). PCO2 levels were unrelated to arterial O2 saturation or PaO2. No relationship was found between the PCO2 and BAL lymphocyte counts. The findings suggest that in fibrosing alveolitis, the arterial PCO2 may be used as an indicator of the state of the inflammatory component of the alveolitis.

Drug-induced lipidosis and the alveolar macrophage

The alveolar macrophage is the principal component of the defense mechanisms of the lung. As a result, alterations in its function can predispose the host organism to pulmonary disease or damage. This cell shows toxic responses to a wide variety of chemicals which are delivered to the lungs by either inhalation or via the systemic circulation. In this regard, this review will focus on the effects of a group of cationic amphiphilic drugs which when administered to humans and animals causes a lysosomal storage disorder of lipids, principally phospholipids, in alveolar macrophages. The susceptibility to the disorder is species-dependent and can be induced in fetal, neonatal and adult animals. Evidence exists that the accumulation of lipids within the cells occurs as a result of an impairment in lipid catabolism, however, not all of the available data are consistent with this theory. In light of this, other mechanisms to explain the etiology of this lipidosis are discussed. Associated with the increase in lipid content within the cell, striking morphological, biochemical and functional changes occur to the alveolar macrophage. Available data indicate that afflicted cells have an increased phagocytic activity and exhibit enhanced killing of one strain of bacteria. While these data suggest an enhancement in certain cellular functions, inadequate information presently exists to allow conclusions to be drawn concerning the consequences of this disorder.

Fibreoptic bronchoscopy: ten years on

Fibreoptic bronchoscopy was introduced more than 10 years ago and is now in many centres a routine diagnostic procedure, having superseded rigid bronchoscopy. Its major role is in the diagnosis of bronchial carcinoma, where the results are as good as, if not better than, results with the rigid instrument. Other major applications have been found in investigating haemoptysis, transbronchial lung biopsy in interstitial lung disease, and in the critically ill patient in the intensive care unit. More recently, the instrument has been used to perform bronchoalveolar lavage in investigating interstitial lung diseases and to enable lobar and segmental lung function studies to be performed. Fibreoptic bronchoscopy is a major advance in the diagnosis of pulmonary diseases, but there will always be times when rigid bronchoscopy is preferable.