A procedure for the isolation of asbestos bodies from lung tissue by exploiting their magnetic properties: a new approach to asbestos body study

Our plain-English summary of A procedure for the isolation of asbestos bodies from lung tissue by exploiting their magnetic properties: a new approach to asbestos body study, by V. Borelli, C. Brochetta, M. Melato, et al (Journal of Toxicology and Environmental Health. Part a, 2007).

The study

• Authors: V. Borelli, C. Brochetta, M. Melato, C. Rizzardi, M. Polentarutti, C. Busatto, F. Vita, R. Abbate, R. Gotter, G. Zabucchi
• Journal: Journal of Toxicology and Environmental Health. Part a
• Published: 2007;70(14):1232-40
• Cited by: 21 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The role of asbestos bodies (and associated proteinacious coating) in asbestos associated diseases is not well understood. Currently employed methods of isolation of these bodies employ harsh chemicals that lead to destruction of their proteinacious coating. In this work a method was developed that enabled the purification of whole, integral, unmodified asbestos bodies (AB) by exploiting their magnetic properties. Albumin and ferritin were found to be the major proteins associated with AB isolated from lung tissue of mesothelioma patients. Magnetically isolated AB were shown to be cytotoxic and to activate free radical production from inflammatory cells at a higher extent than that induced by bodies obtained by chemical digestion. The finding that hypochlorite-treated AB induce DNA damage, while AB obtained by the method described in this article failed to do so, together with the differential behavior of these bodies toward inflammatory cells, suggests that native asbestos bodies should be used to investigate the pathogenetic role of these structures.

In plain English

This laboratory study, from the University of Trieste, Italy, described a new way to isolate asbestos bodies (asbestos fibers coated with iron-containing and protein material in the lung) without the harsh chemicals, such as bleach, normally used. The authors used lung tissue from four patients who died of mesothelioma and had worked in a ship-building industry. They separated the bodies from the tissue with a magnet. About two-thirds of the isolated bodies were intact, and most of the core fibers tested were consistent with crocidolite. The two main coating proteins identified were albumin and a ferritin subunit. In tests with human white blood cells (neutrophils) from healthy donors, only the magnetically isolated bodies significantly killed the cells and raised production of superoxide, a free radical. Bleach-treated bodies and the asbestos fibers tested (amosite and chrysotile for cell killing, plus crocidolite for superoxide) had no statistically significant effect under the test conditions. In a DNA test, bleach-treated bodies broke DNA, while magnetically isolated bodies and crocidolite fibers did not. The authors concluded that bodies isolated by chemical digestion are not an adequate tool for studying how asbestos bodies contribute to disease.

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 (in vitro) methods study: development of a magnetic isolation procedure for asbestos bodies, followed by tests of their coating proteins and their effects on human neutrophils and on DNA
• Who was studied: Autopsy lung tissue from four patients who died of mesothelioma and had a history of asbestos exposure from employment in a ship-building industry (Fincantieri, Monfalcone, Gorizia, Italy). Neutrophils from blood of healthy donors were used in the cell experiments.
• Exposure: Occupational asbestos exposure in ship-building. Each lung sample contained more than 120,000 asbestos bodies per gram of dried lung tissue. Bodies isolated by magnet (mAB) were compared with part of the same preparation soaked in commercial bleach for 3 days (hdAB), and with crocidolite, amosite and chrysotile fiber samples.
• Main results:
  • About two-thirds of the magnetically isolated bodies were unaltered and intact. In the remaining one-third, the bodies appeared fragmented or the coating was partly removed.
  • Five bodies per autopsy were cut open and their core fibers analysed. Most contained a silicate with an elemental composition consistent with crocidolite asbestos.
  • Proteins released from the magnetically isolated bodies showed 4 bands at about 67, 23, 14 and 6 kD. The 67-kD band was identified as albumin and the 23-kD band as a ferritin protein subunit.
  • Under the experimental conditions used, only the magnetically isolated bodies had significant cytotoxic activity against neutrophils, reaching a maximum at 6 bodies per 100 neutrophils. The asbestos fibers tested (amosite and chrysotile) and bleach-treated bodies did not have significant cytotoxic activity.
  • Only the superoxide produced by neutrophils exposed to magnetically isolated bodies was significantly different from the resting value. The asbestos fibers tested (chrysotile, crocidolite and amosite) and bleach-treated bodies did not significantly influence superoxide production.
  • Bleach-treated bodies caused DNA fragmentation, but magnetically isolated bodies did not cause DNA breaks.
  • No DNA fragmentation was found with uncoated crocidolite fibers.
• The authors' conclusion: The authors concluded that asbestos bodies isolated by chemical digestion are not an adequate tool to study the role of asbestos bodies in disease. They suggested that bleach-treated bodies might give false positive results and that magnetically isolated bodies need to be used for this purpose.
• Limitations the authors state:
  • About one-third of the isolated bodies were fragmented or partly stripped of coating. The authors attributed this probably to freezing and thawing or to mechanical stress during isolation.
  • The protein analysis could not identify the two lightest protein bands (14 and 6 kD).

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Bodies, Asbestos Body Formation, Ferritin, Mesothelioma.

Related studies

• Peroxidase-like activity of ferruginous bodies isolated by exploiting their magnetic property — V. Borelli, E. Trevisan, et al. (2012)
• A procedure for the isolation of amosite asbestos and ferruginous bodies from lung tissue and sputum — M.G. Williams, R.F. Dodson, et al. (1982)
• Magnetic lung measurements of relation to occupational exposure in asbestos miners and millers of Quebec — D. Cohen, T.S. Crowther, et al. (1981)
• Ferromagnetic contamination in the lungs and other organs of the human body — D. Cohen (1973)
• Chemo-physical properties of asbestos bodies in human lung tissues studied at the nano-scale by non-invasive, label free x-ray imaging and spectroscopic techniques — F. Bardelli, F. Brun, et al. (2021)
• Numbers of asbestos bodies on iron-stained tissue sections in relation to asbestos body counts in lung tissue digests — V.L. Roggli, P.C. Pratt (1983)

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