Asbestos bodies in bronchoalveolar lavage fluids of brake lining and asbestos cement workers

Asbestos bodies count and morphometry in bulk lung tissue samples by non-invasive X-ray micro-tomography

The number of the Asbestos Bodies (AB), i.e. asbestos that developed an iron-protein coating during its permanence in biological tissues, is one of the most accessible markers of asbestos exposure in individuals. The approaches developed to perform AB count in biological tissues are based on the manual examination of tissue digests or histological sections by means of light or electron microscopies. Although these approaches are well established and relatively accessible, manual examination is time-consuming and can be reader-dependent. Besides, approximations are applied because of the limitations of 2D readings and to speed up manual counts. In addition, sample preparation using tissue digests require an amount of tissue that can only be obtained by invasive surgery or post-mortem sampling. In this paper, we propose a new approach to AB counting based on non-destructive 3D imaging, which has the potential to overcome most of the limitations of conventional approaches. This method allows automating the AB count and determining their morphometry distribution in bulk tissue samples (ideally non-invasive needle biopsies), with minimal sample preparation and avoiding approximations. Although the results are promising, additional testing on a larger number of AB-containing biological samples would be required to fully validate the method.

Comparative analysis of induced sputum and bronchoalveolar lavage fluid (BALF) profile in asbestos exposed workers

Background

Biological monitoring of healthy workers exposed to hazardous dusts lack validated screening tools. Induced sputum (IS) cellular profile was compared with bronchoalveolar lavage fluid (BALF) profile in asbestos exposed workers in order to assess its usefulness in monitoring workers exposed to asbestos for a long period of time.

Methods

IS and BALF analysis was performed in 39 workers of a car brakes and clutches factory that uses chrysotile asbestos. Selection criteria were an employment history of > 15 years and the absence of a diagnosis of pneumonoconiosis. The type of cells, the existence of dust cells, of iron laden macrophages and of asbestos bodies were assessed and compared between IS and BALF samples.

Results

35 IS samples (90%) had dust cells, 34 (87%) iron laden macrophages and in 8 samples (21%) asbestos bodies were found. In most samples neutrophils were dominated. Samples with asbestos bodies (ABs) had significantly higher lymphocytes and lower neutrophils count compared with the samples without ABs. Macrophages and neutrophils in IS and BALF exhibited significant inter-relations (Spearman's rho: 0.26-0.29, p < 0.05) while IS lymphocytes count showed an inverse relation with BALF neutrophils (Spearman's rho: -0.36). Neutrophils and dust cells were highly correlated between the samples (Spearman's rho: 0.35, p < 0.05) while IS dust cells and lymphocytes were inversely related (Spearman's rho: -0.36, p < 0.05). More years of employment in the company was related with more neutrophils (Spearman's rho: 0.26) and less lymphocytes (Spearman's rho: -0.33) count. In multivariate analysis the presence of AB in IS samples was strongly related to the presence of asbestos bodies and lymphocytes count in BALF samples.

Conclusions

IS and BALF analysis showed a similar cellular profile indicating that IS sampling in exposed workers to asbestos as a less invasive and expensive method may be useful in providing an insight both for inhalation of dusts and inflammatory processes in the lung.

Patterns of pulmonary dysfunction in asbestos workers: a cross-sectional study

BACKGROUND

Restrictive patterns of pulmonary function abnormalities associated with asbestos exposure are well described. Studies are less consistent, however, regarding the association of asbestos inhalation with airway dysfunction and obstructive impairment.

METHODS

We compared pulmonary function test results between 277 chrysotile exposed workers (22% non-smokers) and 177 unexposed controls (50.3% non-smokers). Information on exposure and smoking were collected using a standardized questionnaire. Standardized spirometric and DCLO Measurement methods were utilized. CXRs were read based on ILO pneumoconiosis guidelines.

RESULTS

Asbestos exposed subjects had significantly reduced FVC, FEV1, FEV1/FVC and DLCO. Restricting the analysis to non-smokers, asbestos workers still had about 3% lower FEV1/FVC ratio than controls, but this difference did not reach statistical significance. Among exposed workers, the presence of radiographic evidence of asbestosis further lowered FVC and DLCO but not FEV1/FVC compared to asbestos exposure without radiographic asbestosis. Additionally, smoking asbestos workers had significantly lower DLCO compared to non-smoking workers.

CONCLUSION

Asbestos exposure, especially when radiographic evidence of interstitial fibrosis from asbestosis is present, leads to significant decreases in FVC, FEV1 and the DLCO. However, asbestos exposure alone is not significantly associated with a reduction of the FEV1/FVC. Smoking-asbestos workers had significantly lower DLCO than their non-smoking counterparts. Whether asbestos interacts with smoking additively or synergistically on DLCO needs further investigation. Similarly, further studies are needed to assess the progression and clinical significance of asbestos induced airway dysfunction.

Grand rounds: asbestos-related pericarditis in a boiler operator

CONTEXT

Occupational and environmental exposures to asbestos remain a public health problem even in developed countries. Because of the long latency in asbestos-related pathology, past asbestos exposure continues to contribute to incident disease. Asbestos most commonly produces pulmonary pathology, with asbestos-related pleural disease as the most common manifestation. Although the pleurae and pericardium share certain histologic characteristics, asbestos-related pericarditis is rarely reported.

CASE PRESENTATION

We present a 59-year-old man who worked around boilers for almost 30 years and was eventually determined to have calcific, constrictive pericarditis. He initially presented with an infectious exacerbation of chronic bronchitis. Chest radiographs demonstrated pleural and pericardial calcifications. Further evaluation with cardiac catheterization showed a hemodynamic picture consistent with constrictive pericarditis. A high-resolution computerized tomography scan of the chest demonstrated dense calcification in the pericardium, right pleural thickening and nodularity, right pleural plaque without calcification, and density in the right middle lobe. Pulmonary function testing showed mild obstruction and borderline low diffusing capacity.

DISCUSSION

Based on the patient's occupational history, the presence of pleural pathology consistent with asbestos, previous evidence that asbestos can affect the pericardium, and absence of other likely explanations, we concluded that his pericarditis was asbestos-related.

RELEVANCE TO CLINICAL PRACTICE

Similar to pleural thickening and plaque formation, asbestos may cause progressive fibrosis of the pericardium.

Electron microscopic microanalysis of bronchoalveolar lavage: a way to identify exposure to silica and silicate dust

OBJECTIVES

The diagnostic implications of finding non-fibrous inorganic particles in bronchoalveolar lavage (BAL) fluid has not been fully assessed. The aim of this study has been to measure the silica and non-fibrous silicates in BAL fluid from populations with different exposures to inorganic dust, and to find whether such measurement is useful for diagnostic purposes.

MATERIALS AND METHODS

BAL samples from 19 subjects with only environmental exposure to inorganic dust (group A, mean (SD) age 50.7 (15.2)), 23 subjects with normal chest x ray films exposed to silica or silicates at work (group B, mean (SD) age 52.0 (12.4)), and 15 subjects with a previous diagnosis of silicosis (group C, mean (SD) age 68.0 (6.5)) were studied. Absolute and relative cell counts were found, and the samples were prepared for microanalysis by electron microscopy (EM). Firstly, semiquantitative x ray microanalysis was performed to find the level of silicon (Si) (peak/background Si) and this was followed by microanalysis of individual particles by EM. Variables related to the level of Si detected were assessed with multivariate analysis.

RESULTS

Detected levels were higher in group B (2.09, 95% confidence interval (95% CI) 1.56 to 2.82) and C (1.50, 95% CI 1.07 to 2.12) than in group A (0.87, 95% CI 0.66 to 1.16) (P < 0.05, Dunett t test). A first multivariate analysis showed that exposure to silica or silicates was the only determinant of the level of Si expressed as log peak/background Si, when adjusted for age, sex, smoking habit, and cell count. A second multivariate analysis with microanalysis of individual particles as an independent variable showed the silica count to be the main predictor of detected concentration of Si. Silica and non-aluminium silicates together explain 55.5% (R2) of the variation in detected levels of Si.

CONCLUSIONS

Detected levels of Si in BAL fluid depend on silica count and are higher in subjects with exposure to inorganic dust at work, but will not discriminate between exposed subjects with and without silicosis. Because semiquantitative x ray microanalysis does not accurately define exposure to non-silica inorganic particles, this measurement must be followed by EM microanalysis of individual particles in most cases, especially when exposure to silicates or metal dust is suspected.

Biopersistence of respirable synthetic fibers and minerals: point of view of the chest physician

Problems of diagnosis related to the presence or absence of particles in lung and pleural tissues are discussed from the clinician's viewpoint. The advantage of applying mineralogical analytical techniques is considered.

Airflow obstruction in nonsmoking, asbestos- and mixed dust-exposed workers

Obstructive changes in small airways have been described in patients exposed to asbestos and other mineral dusts. The physiologic significance of these small airways abnormalities and their relationship to dust burden and alveolitis remain unclear. We performed bronchoalveolar lavage (BAL) in 30 nonsmoking and 30 age-matched smoking subjects, all with mild asbestos and mixed dust exposure, to determine if parameters of lung dust burden correlated with spirometric evidence of airflow obstruction. Seventeen of 30 nonsmoking subjects and 24 of 30 smoking subjects met spirometric criteria for airflow obstruction. There were significantly more obstructed subjects in both dust exposed groups (P < 0.05) than in an age-matched nondust exposed group. There was, however, no significant difference in the number of obstructed subjects between the smoking and nonsmoking groups. There was no correlation in either group between airflow obstruction and total or differential cell counts, ferruginous bodies, total asbestos fibers, or the percent of free silica in the particulate fraction recovered by BAL. We conclude that evidence of small airways obstruction occurs commonly in occupationally dust exposed subjects and appears to be related to dust exposure per se and not to alveolar inflammation or fiber retention, important factors in the development of alveolitis and interstitial lung disease.

Small airways dysfunction among non-smoking shipyard arc welders

Increased volume of trapped gas (VTG), indicating small airways dysfunction, was found among 14 never smoking non-atopic welders who had worked for 10-31 (mean 22) years in their occupation. Spirometry and nitrogen wash out data were compared with those from a reference group of 14 never smoking men not exposed to welding. A methacholine provocation test was carried out. The effect was measured by change in forced expiratory volume in one second (FEV1) and VTG. The maximum decrease in FEV1 after inhalation of methacholine was 6% in welders and 2% among referents. Before provocation VTG and VTG total lung capacity (TLC) was higher among welders (127 ml v 98 ml and 1.76% v 1.38%). The increase in VTG and VTG/TLC was higher in welders after inhalation of methacholine at concentrations of 0.001% to 2% and remained increased after inhalation of salbutamol. The differences indicate small airways disease among shipyard welders.