The mechanism of production of asbestos bodies from anthophyllite fibres

Our plain-English summary of The mechanism of production of asbestos bodies from anthophyllite fibres, by P.F. Holt, D.K. Young (The Journal of Pathology and Bacteriology, 1967).

The study

• Authors: P.F. Holt, D.K. Young
• Journal: The Journal of Pathology and Bacteriology
• Published: 1967;93(2):696-9
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Histological studies of sections of guinea-pig lungs suggest that asbestos bodies are derived from the cytoplasm of macrophages that have attempted to ingest asbestos fibres. Proteins are probably adsorbed from the cytoplasm on to the asbestos and this leads to a shrinkage of the structure which produces corrugations or divides the structure into beads.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This study examined how asbestos bodies, which are coated asbestos fibres found in lungs after asbestos is inhaled, are formed. The authors looked at some hundreds of asbestos fibres under the microscope in lung sections from guinea-pigs that had inhaled asbestos dust in an earlier study, which describes the exposure methods. They photographed the few fibres that seemed partway through forming asbestos bodies and deduced a likely sequence from these. Anthophyllite produced the largest and most characteristic asbestos bodies. Short fibres, up to about 5 micrometres, were almost all inside cells. The authors inferred that an extension of a scavenger cell (macrophage) flows along a fibre too long to engulf and can leave cell material behind, coating part or all of the fibre. They proposed that protein from this material attaches to the fibre, causing shrinkage that produces beaded or corrugated shapes. The authors concluded that their sections suggest asbestos bodies come from the cytoplasm of macrophages that tried to ingest asbestos fibres. They noted unexplained features, including when iron enters the coating.

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 study: microscope examination of lung tissue sections from guinea-pigs exposed by inhalation in an earlier experiment
• Who was studied: Lung sections from guinea-pigs used in an earlier experiment (Holt, Mills and Young, 1966); the number of animals is not given in this article; some hundreds of fibres were examined
• Exposure: Inhaled asbestos dust, with the article focusing on anthophyllite fibres; dusting apparatus and exposure times are given in the earlier report, not in this article
• Main results:
  • Anthophyllite produced the largest and most characteristic asbestos bodies
  • In the guinea-pig lungs, shorter fibres (up to about 5 micrometres long) were almost all inside cells
  • A few very long fibres, some longer than 100 micrometres, were embedded in tissue
  • In most cases a fibre entered a cell only when the cell had contacted the end of the fibre
  • The authors deduced that a macrophage's extension (process) that contacts the end of a fibre normally flows along it, engulfing it if the fibre is short
  • The authors deduced that when the extension is withdrawn from a fibre too long to engulf, it may leave a small blob of cytoplasm that becomes a sphere on the fibre
  • The authors described the cell extension detaching after spreading along the fibre, leaving the fibre coated along all or part of its length
  • The authors proposed that protein adsorption and loss of water cause the coating to shrink, producing corrugation
  • One large asbestos body, 25 micrometres long, was built around part of a fibre about 80 micrometres long, with the fibre projecting from one end
• The authors' conclusion: The authors concluded that their sections suggest asbestos bodies are derived from the cytoplasm of macrophages that attempted to ingest asbestos fibres, and that protein adsorption probably causes shrinkage that produces corrugations or beads
• Limitations the authors state:
  • The sequence of formation was deduced from only the few fibres that appeared to be in a transition state
  • It is unlikely that a whole long fibre and its attached cell lie in the plane of a single tissue section
  • Some features remained unexplained, including regularly spaced granules and the stage at which iron enters the coating

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos Bodies, Anthophyllite, Macrophage.

Related studies

• The mechanism of formation of asbestos bodies — S.K. Botham, P.F. Holt (1968)
• Particle size of latex beads dictates IL-1β production mechanism — T. Adachi, K. Takahara, et al. (2013)
• The development of glass-fibre bodies in the lungs of guinea-pigs — S.K. Botham, P.F. Holt (1971)
• The mechanism of pleural inflammation by long carbon nanotubes: interaction of long fibres with macrophages stimulates them to amplify pro-inflammatory responses in mesothelial cells — F.A. Murphy, A. Schinwald, et al. (2012)
• Comparison of effects on macrophage cultures of glass fibre, glass powder, and chrysotile asbestos — E.G. Beck, P.F. Holt, et al. (1972)
• Stimulation of oxidant production in alveolar macrophages by pollutant and latex particles — G.E. Hatch, D.E. Gardner, et al. (1980)

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