Excessive accumulation of asbestos fibre in the bronchoalveolar space may be a marker of individual susceptibility to developing asbestosis: experimental evidence

Our plain-English summary of Excessive accumulation of asbestos fibre in the bronchoalveolar space may be a marker of individual susceptibility to developing asbestosis: experimental evidence, by R. Bégin, P. Sébastien (British Journal of Industrial Medicine, 1989).

The study

• Authors: R. Bégin, P. Sébastien
• Journal: British Journal of Industrial Medicine
• Published: 1989;46(12):853-5
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Free full text

Abstract

Earlier studies have shown that only 60% of sheep exposed to a given chrysotile exposure developed asbestosis. Analyses of lung lavage (BAL) fibre content early in the disease showed that, despite identical injected doses, the subset of sheep with interstitial lung disease had significantly more fibre retention. To determine if the fibre retention preceded or followed early disease, 15 were exposed at 10 day intervals to 100 mg chrysotile by intratracheal injection. Animals were studied at three month intervals by chest radiograph (CR) and BAL. At month 15, 10 sheep had definitely abnormal CR (group B) and five had normal CR (group A). Fibre analyses of BAL reproduced earlier finding of a higher level of fibre retention early in the disease, month 15: 92 +/- 2 f/microliter in group B v 35 +/- 19 in group A. Moreover, at month 3, when no disease was detectable, group B already had a significantly higher fibre retention level: 84 +/- 2 in group B v 52 +/- 3 in group A (p less than 0.05). These data clearly imply that high alveolar dust retention precedes the disease process and that alveolar dust clearance capacity may be a major determinant of asbestosis.

In plain English

This was an experiment in sheep. It tested whether sheep that go on to develop asbestosis already hold more asbestos fibres in their lungs before the disease appears. The authors used 25 sheep. Ten received salt solution only, and 15 received 100 mg of chrysotile asbestos infused into the windpipe every 10 days. The authors checked the sheep with chest x rays and lung washings (bronchoalveolar lavage), and counted fibres in the washings at months 3 and 15. The control sheep's x rays stayed normal. By month 15, 10 of the 15 exposed sheep had definitely abnormal x rays (early asbestosis) and 5 did not. At month 15, sheep with asbestosis averaged 92 fibres per microlitre of washing fluid, against 35 in exposed sheep without it. At month 3, when no disease was detectable, the figures were 84 against 52, a statistically significant difference. Fibre length was comparable between the groups. The authors concluded that high fibre retention comes before the disease, and that the ability to clear dust from the lungs may be a major determinant of asbestosis.

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: Animal experiment in sheep (repeated measurements on the same animals over time)
• Who was studied: 25 sheep weighing 25 to 40 kg: 10 controls given phosphate buffered saline only and 15 exposed to chrysotile; Sherbrooke and Montreal, Quebec, Canada
• Exposure: 100 mg UICC Canadian chrysotile asbestos in 100 ml phosphate buffered saline, infused into the trachea every 10 days until disease was clearly detected by chest radiograph in more than half the exposed animals
• Main results:
  • The chest radiographs of the 10 control sheep remained normal throughout the study
  • By month 15, 10 of the 15 asbestos-exposed sheep had a definitely abnormal (ILO category 1) chest radiograph (group B, early asbestosis) and 5 had normal radiographs (group A). The first abnormal radiograph appeared during month 9.
  • At month 15, fibre content of lung lavage fluid was 92 plus or minus 2 fibres per microlitre in group B (with asbestosis) versus 35 plus or minus 19 in group A (without asbestosis). Values are means with standard error.
  • At month 15, fibre content was 2.6 times higher in group B than in group A (p less than 0.05)
  • At month 3, when all exposed sheep had normal radiographs, fibre content was already significantly higher in group B: 84 plus or minus 2 versus 52 plus or minus 3 fibres per microlitre in group A (p less than 0.05)
  • Fibre length was comparable in both groups of sheep
• The authors' conclusion: The authors concluded that high alveolar dust retention precedes the disease process and that alveolar dust clearance capacity may be a major determinant of asbestosis (of individual susceptibility to developing it).

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Chrysotile, Interstitial Lung Disease, Chest X-Ray.

Related studies

• Mass, number and size of lung fibres in the pathogenesis of asbestosis in sheep — P. Sébastien, R. Bégin, et al. (1990)
• Biochemical components of bronchoalveolar lavage in early experimental asbestosis of the sheep: phospholipase A2 activity, prostaglandin E2 and proteins — P. Sirois, G. Drapeau, et al. (1983)
• Assessment of progression of asbestosis in the sheep model by bronchoalveolar lavage and pulmonary function tests — R. Bégin, M. Rola-Pleszczynski, et al. (1983)
• Pulmonary and systemic immunoregulatory changes during the development of experimental asbestosis — M. Rola-Pleszczynski, S. Gouin, et al. (1984)
• Contributions of experimental asbestosis in sheep to the understanding of asbestosis — R. Bégin, A. Cantin, et al. (1991)
• Asbestos bodies in bronchoalveolar lavage in relation to asbestos bodies and asbestos fibres in lung parenchyma — A. Karjalainen, R. Piipari, et al. (1996)

Browse more research in British Journal of Industrial Medicine, or return to medical research.