Asbestos Retention In Human Respiratory Tissues: Comparative Measurements In Lung Parenchyma And In Parietal Pleura

Our plain-English summary of Asbestos Retention In Human Respiratory Tissues: Comparative Measurements In Lung Parenchyma And In Parietal Pleura, by P. Sebastien, X. Janson, A. Gaudichet (1980).

The study

• Authors: P. Sebastien, X. Janson, A. Gaudichet
• Published: Biological Effects Of Mineral Fibres (J.C. Wagner, Editor), Lyon: Iarc Scientific Publications, Volume 30, Pp. 237-246 (1980)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library, J-M no. 004989. The article is still under copyright, so we describe it here rather than post it.

In plain English

This French study measured asbestos fibres in autopsy tissue from 29 people with varied exposure, including asbestos textile, cement and shipyard workers. Pathologists had sent the cases to confirm a diagnosis. Using a transmission electron microscope, the authors examined 112 tissue samples, including samples of lung and of parietal pleura, the lining of the chest wall. Results were significantly positive for fibres in lung samples in 27 of the 29 cases, but in pleural samples in only 16. There was no evident relationship between lung and pleural concentrations. In the lungs, amphibole-type fibres were 0 to 100% of fibres, mean 56. In the pleura, almost all fibres were chrysotile, which was over 90% of fibres in 30 of 40 pleural samples. Pleural fibres were also shorter: mean length 2.3 micrometres against 4.9 in lung. The authors concluded that pleural retention cannot be derived from lung measurements, and that in these people with mixed exposure, chrysotile seemed to be almost the only asbestos type retained in pleural tissue. They noted that unevenly spread pleural fibres could be missed by the microscope.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Autopsy case series comparing asbestos fibre content of lung tissue and parietal pleura by transmission electron microscopy
• Who was studied: 29 autopsy cases (112 tissue samples in total) sent to the laboratory by pathologists requesting confirmation of diagnosis. The authors were based in Paris and Créteil, France. Each case had lung samples from different sites and parietal pleural samples, and a few also had mediastinal lymph nodes.
• Exposure: Mixed types of asbestos dust in varied jobs listed in Table 1. These included asbestos textile workers, shipyard insulators and workers, asbestos cement and mill workers, asbestos sheet cutters, dock workers, boiler makers, brake maintenance and repair, plumber, glass maker and others. Some cases had exposure 'undiscovered' or only 'probable' or 'occasional'.
• Main results:
  • Lung samples were significantly positive for fibres in 27 of 29 cases. Concentrations ranged from 'not detected' to 420 (unit printed as '10°/cc'; the exponent is unreadable in the scan).
  • Parietal pleural samples were significantly positive in only 16 of 29 cases. Concentrations ranged from 'not detected' to 51, in the same garbled unit.
  • There was no evident relationship between the highest lung concentration and the highest pleural concentration in each case.
  • The pleural sample types were significantly positive at these rates: normal costal tissue 5 of 15, costal plaques 7 of 11 (64%), diaphragmatic plaques 5 of 7.
  • In lung, the proportion of amphibole-type fibres ranged from 0 to 100% (mean 56, standard deviation 32). Positive pleural samples contained almost all chrysotile.
  • In each case, the proportion of chrysotile was higher in pleura than in lung. Chrysotile made up more than 90% of fibres in 30 of the 40 pleural samples.
  • Mean fibre sizes, lung versus pleura: length 4.9 vs 2.3 micrometres; diameter 0.13 vs 0.06 micrometres. Fibres longer than 4 micrometres were 42% vs 16%; fibres longer than 8 micrometres were 15% vs 2%.
  • Among thin chrysotile fibres (diameter 0.03 to 0.25 micrometres), fibres 0.4 to 4 micrometres long were 60% in lung vs 84% in pleura. Fibres longer than 4 micrometres were 38% vs 14%. Few thick chrysotile fibres were seen.
  • Only one case (number 26) had a significant amount of amphibole-type fibre in the pleura. In that case, thin amphiboles were shorter in pleura than in lung. For thicker amphibole fibres, short and long fibre frequencies were not significantly different.
• The authors' conclusion: The authors concluded that asbestos retention in parietal pleura cannot be derived from lung measurements. In these cases with mixed exposure, chrysotile seemed to be almost the only asbestos type retained in parietal pleural tissue. They suggested this might be taken into account when assessing the risk of pleural diseases, especially mesothelioma, attributable to each fibre type. They also wrote that the findings stress a poor understanding of how mesothelioma arises in humans.
• Limitations the authors state:
  • Many negative pleural samples may reflect uneven distribution of fibres in pleura. Concentrated fibres could be missed because the electron microscope examines a very small sample.
  • Autopsy studies are of limited value for explaining how fibres move in the respiratory tract. Fibre content reflects past retention, translocation and clearance in tissue changed by disease, so experimental data are needed.

Topics

Medical terms in this study, explained in our Lexicon: Parenchyma, Parietal Pleura, Autopsy, Amphibole Group, Pleura, Chrysotile.

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