Comparative studies on the cytotoxicity of amphibole and serpentine asbestos

Our plain-English summary of Comparative studies on the cytotoxicity of amphibole and serpentine asbestos, by J.E. Craighead, B.T. Mossman, B.J. Bradley (Environmental Health Perspectives, 1980).

The study

• Authors: J.E. Craighead, B.T. Mossman, B.J. Bradley
• Journal: Environmental Health Perspectives
• Published: 1980;34:37-46
• Type of article: Review
• Cited by: 27 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The chemical and physical properties of serpentine and amphibole asbestos are considered in the context of their interaction with tissue of the tracheobronchial tree and lungs. In vitro studies in cultures of several types are evaluated and work with the erythrocyte hemolysis system is reviewed. Although fibers of the two major mineral types differ substantially, it is likely they are modified by secretions and membranes of cells after inhalation to the respiratory tract. Investigations using virgin asbestos might not provide an accurate picture of events in vitro.

In plain English

This paper, by three authors from a pathology department in Vermont, was a review comparing serpentine asbestos (chrysotile) with amphibole asbestos (mainly crocidolite) in laboratory studies. It drew on published work and on the authors' own laboratory experiments, some using human red blood cells, and was not a study of health in exposed people. In the authors' red blood cell work, chrysotile caused marked changes in cell shape soon after it was added. Crocidolite broke down red cells only after prolonged exposure and without those shape changes. Chrysotile coated with albumin or sialic acid, or acid-treated, did not make the cells leak. In cultures of hamster windpipe (tracheal) lining cells, chrysotile slowed growth over a range of doses; equivalent amounts of crocidolite had no effect. In hamster tracheal tissue cultures, both fiber types damaged the surface lining, chrysotile more so, while the deeper basal cells stayed intact. The authors concluded that the surface and form of both kinds of asbestos are altered after inhalation, so studies using untreated ("virgin") fibers may not reflect events in the body.

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: Review of laboratory (in vitro) studies comparing serpentine and amphibole asbestos, including summaries of the authors' own cell and organ culture experiments
• Who was studied: Laboratory systems, not a study of health in exposed people. These were human red blood cells (erythrocytes), monolayer cultures of hamster tracheal epithelial cells, and hamster tracheal organ cultures, studied at the University of Vermont. Cell numbers and dates are not given.
• Exposure: Chrysotile (serpentine) compared with crocidolite (amphibole). Amosite and anthophyllite are discussed as other amphiboles. Doses were given in mg/ml of culture medium, but the figures are not legible enough to report them reliably.
• Main results:
  • In the authors' red blood cell studies, chrysotile caused dramatic changes in cell shape shortly after it was added to a cell suspension.
  • Chrysotile did not make red cells leak hemoglobin when the fibers were coated with albumin or sialic acid, or after acid digestion.
  • Crocidolite broke down red blood cells only after prolonged exposure. The cell shape changes did not develop, and the fiber-cell contact was less intimate.
  • In hamster tracheal epithelial monolayer cultures, chrysotile inhibited cell growth over a range of doses. Equivalent amounts of crocidolite had no effect.
  • In hamster tracheal organ cultures, both crocidolite and chrysotile were cytotoxic to the differentiated mucociliary cell layer, and the cytotoxicity of chrysotile was more pronounced.
  • In the organ cultures, the basal cells remained intact with both fiber types. In an earlier report by two of the authors, basal cells exposed to crocidolite took up the particles and underwent hyperplasia and metaplasia.
• The authors' conclusion: The authors concluded that the surface properties and forms of both amphibole and serpentine asbestos are altered after inhalation into the respiratory tract, and that this should be considered when designing in vivo laboratory experiments. They also stated that the amphiboles amosite and crocidolite are less cytotoxic than chrysotile.
• Limitations the authors state:
  • The authors stated that laboratory studies using virgin (untreated) asbestos may not properly simulate events in the body.
  • The authors noted that results from different laboratories conflict, likely because the culture systems and protocols differ. They also noted that dosing by weight may be a poor measure because fiber surface properties appear critical.
  • The authors stated that the role of contaminants on the fibers in causing cell injury was hypothetical, with no conclusive evidence published.

Topics

Medical terms in this study, explained in our Lexicon: Amphibole Group, Serpentine Group, Amphibole Asbestos.

Related studies

• Thermal modification of chrysotile asbestos: evidence for decreased cytotoxicity — R. Valentine, M.J. Chang, et al. (1983)
• Cytotoxicity of oxidants and asbestos fibers in cultured human mesothelial cells — V.L. Kinnula, K. Aalto, et al. (1994)
• Cytotoxicity of respirable dusts from industrial minerals: comparison of two naturally occurring and two man-made silicates — D. Nadeau, L. Fouquette-Couture, et al. (1987)
• Factors involved in the cytotoxicity of UICC amosite towards macrophages — R. Davies, D.M. Griffiths, et al. (1983)
• Biological effects and comparative cytotoxicity of thermal transformed asbestos-containing materials in a human alveolar epithelial cell line — F. Giantomassi, A.F. Gualtieri, et al. (2010)
• Influence of crystallization habit of minerals on in vitro cytotoxicity — L.D. Palekar, C.M. Spooner, et al. (1979)

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