Asbestos bodies, their formation, composition and character

Our plain-English summary of Asbestos bodies, their formation, composition and character, by F.D. Pooley (Environmental Research, 1972).

The study

• Author: F.D. Pooley
• Journal: Environmental Research
• Published: 1972;5(4):363-79
• Cited by: 68 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Asbestos bodies extracted from human lungs have been examined under the electron microscope to determine their morphology and diffraction characteristics. The asbestos bodies were extracted from the lungs of persons exposed to the four types of commercial asbestos fiber, namely crocidolite, amosite, anthophyllite and chrysotile. Asbestos bodies were rarely formed on fibers less than 10 µm in length and practically always on straight fibers. They were found to occur on all the four commercial varieties of asbestos but less frequently on chrysotile fibers. The characteristics of the individual fibers were found to play a large part in determining the range and frequency of body shapes observed. There appears to be no evidence to suggest stepwise formation of asbestos bodies. Asbestos bodies were found to have a major crystalline component which is structurally similar to extracts of ferritin produced from animal and human organs. The material forming the asbestos body is definitely biological in origin and corresponded closely to the material defined in the medical literature as hemosiderin.

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

In plain English

This laboratory study, by a single author, used electron microscopy to examine asbestos bodies (coated asbestos fibers) taken at post mortem from the lungs of people with known industrial asbestos exposure. Some had been exposed only to chrysotile, amosite, crocidolite or anthophyllite, and others to mixed dusts. Few bodies had formed on fibers shorter than 10 micrometres, and nearly all bodies and their fibers were straight. Uncoated fibers far outnumbered coated ones. In tissue containing chrysotile, the ratio of uncoated to coated fibers was much larger than in tissue containing amphiboles. Body shapes differed by fiber. On anthophyllite, sheath-like bodies outnumbered segmented ones about four to one. On crocidolite, segmented bodies outnumbered sheath types three to one. On amosite the two were about equal. Diffraction patterns of the coating matched those of ferritin extracts. The author concluded that the properties of each fiber, not a stepwise cycle, likely set body shape. The author also concluded that the coating is biological and corresponds to hemosiderin, and that alkali digestion is the best extraction method.

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: Laboratory electron microscopy and electron diffraction study of asbestos bodies extracted from post-mortem human lung tissue, with comparison against ferritin samples
• Who was studied: Post-mortem lung specimens from people with known industrial exposure to asbestos. Table 3 lists case numbers of 11, 6 and 30 alongside the locations Finland, South Africa and Great Britain, but the scanned table does not allow each number to be matched reliably to an exposure type. The number of bodies examined is not given.
• Exposure: Exposure to only one of chrysotile, amosite, crocidolite or anthophyllite, or to mixed dusts (mainly chrysotile plus amosite or crocidolite)
• Main results:
  • Across all specimens, few bodies had formed on fibers shorter than 10 micrometres, while many were longer than 50 micrometres
  • In nearly all cases, bodies and the fibers they had formed on were straight
  • In all lung specimens, uncoated fibers were far more numerous than coated fibers
  • In tissues containing chrysotile, the ratio of uncoated to coated fibers was much larger than in tissues containing amphibole fibers
  • Bodies formed on all four commercial asbestos types. Bodies on chrysotile were very scarce in tissue from persons exposed only to chrysotile, while bodies were very numerous in tissues containing amphibole fibers.
  • On anthophyllite, sheath-like bodies outnumbered segmented bodies by approximately four to one
  • On crocidolite, segmented bodies were seen more commonly than sheath types, in a ratio of three to one. Rounded and cylindrical segmented forms made up almost 50% of crocidolite bodies.
  • On amosite, the ratio of sheath to segmented forms was approximately equal
  • Diffraction patterns from bodies extracted by KOH digestion matched those of untreated ferritin extracts and of a liver extract described elsewhere as hemosiderin. Ashing altered the body structure to some extent.
• The authors' conclusion: The author concluded that there was no evidence for stepwise formation of asbestos bodies and that fiber properties likely dictate body shape. The author also concluded that the body material is biological in origin and resembles ferritin extracts and hemosiderin, and that alkali digestion is the best extraction method.
• Limitations the authors state:
  • Electron diffraction detects only crystalline material, so other compounds in the bodies may have been missed
  • Bodies prepared by ashing thin sections were often broken by the microtome blade, and fewer bodies were available by this method
  • Variation in protein content cannot be detected by diffraction methods

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Bodies, Crocidolite, Amosite, Anthophyllite, Chrysotile, Crystalline, Ferritin, Asbestos Body Formation.

Related studies

• The ultrastructure of asbestos bodies from guinea-pig lungs — J.M. Davis (1964)
• Ferritin adsorption on amosite fibers: possible implications in the formation and toxicity of asbestos bodies — B. Fubini, F. Barceló, et al. (1997)
• Iron associated with asbestos bodies is responsible for the formation of single strand breaks in phi X174 RFI DNA — L.G. Lund, M.G. Williams, et al. (1994)
• Further observations on the ultrastructure and chemistry of the formation of asbestos bodies — J.M. Davis (1970)
• Asbestos dust as a nucleation center in the calcification of old fibrous tissue lesions, and the possible association of this process to the formation of asbestos bodies — J.M. Davis (1970)
• Closing the knowledge gap on the composition of the asbestos bodies — F. Bardelli, C. Giacobbe, et al. (2023)

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