Pascal Dumortier

Guidelines for mineral fibre analyses in biological samples: report of the ERS Working Group

Microscopic techniques for analysing asbestos fibres in lung tissue and bronchoalveolar lavage have provided major information in the understanding of asbestos-related diseases. These analyses are increasingly applied for clinical work and medicolegal problems. Differences in sampling, preparation and counting techniques, definitions of reference populations and expression of results have caused major difficulties in comparing results from different laboratories. Therefore it appeared necessary to set a goal to harmonize these analyses between the European laboratories active in this field. This article summarizes the work of a European Respiratory Society working group with participation from nine European laboratories. The five main issues touched upon are: 1) definitions of control populations and reference levels; 2) sampling, preparation and analytical techniques; 3) asbestos fibres in lung tissues in different pathologies; 4) asbestos bodies in lung tissue, bronchoalveolar lavage and sputum; and 5) basis for the interpretation of fibres and asbestos bodies in biological samples. These guidelines indicate the crucial importance of several factors for the interpretation of the results; namely, adequate sampling, comparable analytical procedures and expression of the results, the use of well-defined reference populations, and a comprehensive understanding of the factors affecting the fibre retention and the dose-responses associated with the different asbestos-related diseases.

Respiratory health effects of man-made vitreous (mineral) fibres

The group of man-made mineral or vitreous fibres (MMMFs or MMVFs) includes glass wool, rock wool, slag wool, glass filaments and microfibres, and refractory ceramic fibres (RCFs). Experimental observations have provided evidence that some types of MMVF are bioactive under certain conditions. The critical role of size parameters has been demonstrated in cellular and animal experiments, when intact fibres are in direct contact with the target cells. It is, however, difficult to extrapolate the results from these studies to humans since they bypass inhalation, deposition, clearance and translocation mechanisms. Inhalation studies are more realistic, but show differences between animal species regarding their sensibility to tumour induction by fibres. Fibre biopersistence is an important factor, as suggested by recent inhalation studies, which demonstrate positive results with RCF for fibrosis, lung tumours and mesothelioma. There is no firm evidence that exposure to glass-, rock- and slag wool is associated with lung fibrosis, pleural lesions, or nonspecific respiratory disease in humans. Exposure to RCF could enhance the effects of smoking in causing airways obstruction. An elevated standard mortality ratio for lung cancer has been demonstrated in cohorts of workers exposed to MMVF, especially in the early technological phase of mineral (rock slag) wool production. During that period, several carcinogenic agents (arsenic, asbestos, polycyclic aromatic hydrocarbons (PAH)) were also present at the workplace and quantitative data about smoking and fibre levels are lacking. It is not possible from these data to determine whether the risk of lung cancer is due to the MMVFs themselves. No increased risk of mesothelioma has been demonstrated in the cohorts of workers exposed to glass-, slag- or rock wool. There are in fact insufficient epidemiological data available concerning neoplastic diseases in RCF production workers because of the small size of the workforce and the relatively recent industrial production.

'Black Spots' and hyaline pleural plaques on the parietal pleura of 150 urban necropsy cases.

The absence of any direct connection between the lung and the parietal pleura raises questions about the mechanisms of pleural migration and retention of inhaled particles. It has been suggested that specific areas of parietal pleura absorb and retain inorganic particles from the pleural space, including carbon pigments and asbestos fibers, and could be starting points for pathologic changes induced by mineral fibers. These particle-collecting structures have been called “black spots.” To study their distribution, macroscopic appearance, and possible relationship with pleural plaques, the parietal pleura of 150 consecutive necropsies of urban dwellers (mean age 67.7 ± 12.9 years) were examined. The size and intensity of spots were scored and recorded on a computer scheme together with information of the presence of pleural plaques. Black spots were observed in 92.7% of the cases. They were mainly located in the lower costal and diaphragmatic zones and could correspond to the anatomic distribution of structures involved in pleural cavity clearance. Scores correlated with sex and age. There was no relationship between the predominant locations of black spots and hyaline pleural plaques.

Erionite bodies and fibres in bronchoalveolar lavage fluid (BALF) of residents from Tuzkoy, Cappadocia, Turkey.

OBJECTIVES The high incidence of malignant mesothelioma in some villages of Cappadocia (Turkey) is due to environmental exposure to erionite fibres. The aim was to evaluate the fibre burden in bronchoalveolar lavage fluid (BALF) from inhabitants of an erionite village and compare it with Turkish subjects with or without environmental exposure to tremolite asbestos. METHODS Ferruginous bodies (FBs) and fibres were measured and analyzed by light and transmission electron microscopy (TEM) in the BALF of 16 subjects originating from Tuzköy. RESULTS FBs were detected in the BALF of 12 subjects, with concentrations above 1 FB/ml in seven of them. Erionite was the central fibre of 95.7% of FBs. Erionite fibres were found in the BALF of all subjects, by TEM, and these fibres were low in Mg, K, and Ca compared with erionite from Tuzköy soil. The mean concentration of erionite fibres in BALF was similar to that of tremolite fibres in Turks with environmental exposure to tremolite. The proportion of fibres longer than 8 μm in BALF represented 35.6% for erionite compared with 14.0% for tremolite. The asbestos fibre concentrations in erionite villagers was not different from that in Turks without environmental exposure to tremolite. CONCLUSION Analysis of BALF gives information about fibre retention in populations environmentally exposed to erionite for whom data on fibre burden from lung tissue samples are scarce. This may apply to exposed Turks having emigrated to other countries.

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

Asbestos body (AB) concentrations in bronchoalveolar lavage samples of 15 brake lining (BL) workers exposed only to chrysotile have been determined and compared with those from 44 asbestos cement (AC) workers extensively exposed to amphiboles. The mean AB concentrations (263 +/- 802 and 842 +/- 2086 AB/ml respectively) for those groups did not differ significantly but were much higher than those found in control groups. Analytical electron microscopy of asbestos body cores showed that in the BL group 95.6% were chrysotile fibres whereas in the AC group amphiboles accounted for 93.1%. The size characteristics of the central fibres differed for chrysotile and amphibole AB, the former being shorter and thinner. Examination of repeated bronchoalveolar lavage samples showed that the mechanisms of clearance of chrysotile fibres do not affect AB concentration for at least 10 months after cessation of exposure. It thus appears that routine counting of ABs in BAL allows the assessment of current or recent occupational exposures to asbestos. Exposures to chrysotile lead to AB concentrations comparable with those encountered in exposures to amphiboles.

Macroscopic assessment of pulmonary emphysema by image analysis.

AIMS--To propose a computerised image analysis based method for measuring, on paper mounted lung sections, the area macroscopically occupied by emphysema. METHODS--The study was based on the assessment of 69 lung sections prepared following a modified Gough-Wentworth technique. The results obtained from image analysis, point counting, and panel grading methods were compared, as was the repeatability of image analysis and panel grading. RESULTS--The results from image analysis and from point counting were not significantly different (p = 0.609) and significant quadratic regressions (r = 0.96, p < 0.001) were found between measurements from image analysis and from panel grading, the computerised technique being shown to be the most reproducible. CONCLUSIONS--Image analysis is a valuable and reproducible method to measure the area of lung macroscopically involved by emphysema.

Chrysotile and tremolite asbestos fibres in the lungs and parietal pleura of Corsican goats

Background and Aims: Environmental exposures to chrysotile and tremolite from the soil cause pleural plaques and mesothelioma in northeast Corsica. Goats grazing in the contaminated areas inhale asbestos fibres. We used this natural animal model to study whether these exposures actually result in increased fibre burdens in the lungs and parietal pleura. Methods: Ten goats from areas with asbestos outcrops and two from other areas were slaughtered. Fibre content of lung and parietal pleural samples was determined by analytical transmission electron microscopy. Results: Both chrysotile and tremolite fibres were detected. In the exposed goats, the geometric mean concentrations of asbestos fibres longer than 1 μm were 0.27 × 106 fibres/g dry lung tissue and 1.8 × 106 fibres/g dry pleural tissue. Asbestos fibres were not detected in the lungs of the two control goats. Chrysotile fibres shorter than 5 μm were predominant in the parietal pleura. Tremolite fibres accounted for 78% and 86% of the fibres longer than 5 μm in lung and parietal pleural samples, respectively. Conclusions: Environmental exposure in northeast Corsica results in detectable chrysotile and tremolite fibre loads in the lung and parietal pleura of adult goats. Tremolite fibres of dimensions with a high carcinogenic potency are detected in the parietal pleura.

Analysis of asbestos bodies in BAL from subjects with particular exposures

Four patients with asbestos-related diseases and with unusual exposures underwent bronchoalveolar lavage (BAL) for mineralogical analysis. Asbestos bodies (AB) were counted by light microscopy and analyzed by transmission electron microscopy and X-ray energy spectrometry. ABs were found in all cases, after a mean delay from the end of exposure of 27.7 years. Analysis of the core fibers indicated the type of alveolar asbestos burden and was compared with the previous exposures: Pleural plaques due to household exposure to amosite and crocidolite. Pleural plaques due to occult occupational exposure to crocidolite in a coal miner. Asbestosis due to environmental exposure to tremolite in Turkey. Asbestosis, pleural plaques, and peritoneal mesothelioma due to a short, intense exposure to crocidolite. AB counting in BAL and identification of the central fibers by analytical electron microscopy is a useful, non-invasive and reliable method to evaluate the alveolar retention of bio-persistent fibers and to relate them to specific exposures.

High Risk of Malignant Mesothelioma and Pleural Plaques in Subjects Born Close to Ophiolites

BACKGROUND Ophiolites, a special sequence of geologic rock units, are known sources of naturally occurring asbestos. The aim of this study was to test whether the occurrence of malignant mesothelioma (MM) or pleural plaques (PPs) in the province of Sivas, Turkey, is determined by the proximity of the patients birthplace to ophiolites and, if so, to establish the magnitude of the risk. METHODS The birthplaces of patients with MM or PPs (cases) and patients with prostate or breast cancer (control subjects), diagnosed between 2000 and 2010 and identified through a mandatory cancer registry or from hospital records (PPs), were located on a geologic map, and the nearest distance to ophiolites was measured. The relation of MM or PPs with distance to ophiolites was analyzed by logistic regression. Samples of soil and house plaster were determined by x-ray diffraction. RESULTS Patients with MM (n = 100) or PPs (n = 133) were born significantly nearer to ophiolites (median distance, 4.5 km for men, 0 km for women) than were patients with prostate cancer (n = 161) or breast cancer (n = 139) (median distance, 20 km for both). ORs were 1.6 (men) ( P < .001) and 2.0 (women) ( P < .001) for every 5-km decrease in the distance of birthplace to ophiolites for MM, compared with prostate and breast cancer, respectively. CONCLUSION In this area without substantial industrial asbestos use, there is an association between the occurrence of mesothelioma (and of PPs) and the proximity of the subjects birthplace to ophiolites.

The role of environmental and occupational exposures in Turkish immigrants with fibre-related disease

Environmental exposure to tremolite and erionite causes endemic diseases of the lung and pleura in Turkey. This study aimed to evaluate the impact of these exposures and further occupational exposures on fibre-related diseases in Turkish immigrants living in Belgium. The study included 51 males and 17 females that emigrated < 1-38 yrs ago. Most of them (n=46) had nonmalignant pleural lesions, one had asbestosis and one had mesothelioma. Environmental asbestos exposure was likely for the majority of patients (60%), but there were also reports of possible occupational asbestos (n = 14) and erionite (n = 2) exposure. Tremolite was the main fibre type in bronchoalveolar lavage fluid (BALF). Elevated concentrations of amosite or crocidolite were detected in only two patients. The delay elapsed since the end of the environmental exposure had no influence on the asbestos body or the tremolite fibre concentrations in the BALF of Turkish immigrants. Most fibre-related diseases in Turkish immigrants are probably due to environmental rather than occupational exposure. Precise information about geographical origin and occupation should be obtained when investigating these patients. Mineralogical analysis of bronchoalveolar lavage fluid gives valuable information on the type and intensity of exposure, especially in patients with both environmental and occupational exposure.