Biological in vitro and in vivo responses of chrysotile versus amphiboles

Our plain-English summary of Biological in vitro and in vivo responses of chrysotile versus amphiboles, by J. Bignon, M.C. Jaurand (Environmental Health Perspectives, 1983).

The study

• Authors: J. Bignon, M.C. Jaurand
• Journal: Environmental Health Perspectives
• Published: 1983;51:73-80
• Type of article: Review
• Cited by: 22 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Although all commercial forms of asbestos have been demonstrated to be carcinogenic in animals, so far epidemiological data are controversial concerning what asbestos types are the most carcinogenic and fibrogenic in humans. In order to understand the early cellular events induced by fibrous particles, different in vitro studies (hemolysis, release of enzymes by macrophages, assays on cell culture systems) have been carried out in several laboratories; most of these studies have shown that cell and subcellular in vitro responses were different depending on fiber types: chrysotile versus amphiboles. This presentation compares the results of different laboratories with our data obtained by using a model which modifies the chemistry of the fibers by acid treatment. The acid-leached chrysotile and acid-treated amphibole fibers showed different biological responses in several in vitro systems used in comparison to unleached fibers. These differences in the in vitro reactivity were related to the chemical state of the fibers and might explain the differences in their effects in animals after intrapleural injection as assessed by the percentage of mesothelioma, the latency period, the survival time and the degree of pleural fibrosis. The carcinogenic effect of the fibers is discussed in relation of their in vitro inflammatory or cytotoxic responses.

In plain English

This review compared laboratory and animal studies of chrysotile versus the amphiboles crocidolite and amosite, including the authors' work with acid-treated fibers. In the studies reviewed, chrysotile generally damaged red blood cells more than amphiboles and was more toxic in most cell-line studies. Acid treatment lowered these effects for chrysotile and raised them for amphiboles. However, acid-treated chrysotile made macrophages release LDH, which the authors took as a sign of cell damage. In cited rat inhalation studies, chrysotile caused more lung fibrosis than crocidolite. In a 1969 study, fibers were introduced into the space around the lung (pleural cavity). Mesotheliomas developed in 61% of specific pathogen-free rats given chrysotile, 59% given crocidolite and 40% given amosite, and in 69%, 68% and 31% of standard rats. Another study found crocidolite three times as active as chrysotile, but the authors noted a contradictory experiment in that paper. The authors' own rat study found similar mesothelioma numbers with chrysotile and crocidolite but shorter latency with chrysotile. The authors concluded that chrysotile seemed the most reactive fiber and that surface chemistry, not only size, may play a role.

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 in vitro and animal studies from the authors' laboratory and others
• Who was studied: Published in vitro (red blood cells, macrophages, cell lines, rat mesothelial cells) and animal (mainly rat) studies from the preceding decade
• Exposure: Chrysotile versus amphiboles (crocidolite, amosite; anthophyllite in some studies), either untreated or acid-leached (oxalic acid)
• Main results:
  • In hemolysis studies by several authors, chrysotile was more hemolytic than the amphiboles
  • After acid treatment, chrysotile was less hemolytic, whereas acid-treated amphiboles were more hemolytic
  • In cell-line studies, acid treatment decreased the cytotoxicity of chrysotile and increased that of crocidolite and amosite
  • In macrophage studies, acid-treated chrysotile did not release lysosomal enzymes but did release LDH, which the authors described as indicating a cytotoxic effect
  • In macrophage studies, untreated amphiboles appeared cytotoxic, whereas chrysotile acted as an inflammatory stimulus
  • In cited rat inhalation studies (Wagner et al.; Davis et al.), chrysotile caused more lung fibrosis than crocidolite
  • In Wagner and Berry (1969), discussed under pleural carcinogenesis, mesotheliomas occurred in 61% (chrysotile) and 59% (crocidolite) of specific pathogen-free rats, and in 69% and 68% of standard rats. Amosite produced 40% (specific pathogen-free) and 31% (standard).
  • In Wagner et al. (1974), experiment 3, UICC crocidolite was three times as active as UICC chrysotile. In experiment 1 of the same paper, 21 of 59 rats given SFA chrysotile and 11 of 59 given crocidolite had mesotheliomas.
  • In the authors' own laboratory study of intrapleural injection in rats, chrysotile and crocidolite produced about the same number of mesotheliomas. Chrysotile caused a more marked early inflammatory reaction and a shorter latency period.
• The authors' conclusion: The authors concluded that chrysotile seemed the most reactive fiber in vitro and in vivo. They questioned applying the Stanton fiber-size theory generally, and suggested that reactive sites on the fiber surface may also play a role, particularly in cancer.
• Limitations the authors state:
  • In animal studies, other factors (dose, route of exposure, strain and so on) varied between studies
  • Interpreting human data is difficult because people have usually been exposed to mixed fibers
  • More in vitro experiments are needed to clarify macrophage responses

Topics

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

Medical terms in this study, explained in our Lexicon: Chrysotile, Amphibole Group, Carcinogenic, Fibrogenic, Macrophage, Mesothelioma, Latency, Fibrosis.

Related studies

• Biological reactivity of calcium silicate composites--in vitro studies — J. Hunt, F.D. Pooley, et al. (1981)
• Biological effects of chrysotile after SO2 sorption. II. Effects on alveolar macrophages and red blood cells — M.C. Jaurand, J. Bignon, et al. (1978)
• Analysis of amphibole asbestos in chrysotile and other minerals — J. Addison, L.S. Davies (1990)
• Amphiboles and chrysotile asbestos exposure — V.L. Roggli, P.C. Pratt (1988)
• The biological reactivity of calcium silicate composites: in vivo studies — R.J. Richards, T.D. Tetley, et al. (1981)
• In vitro and in vivo genotoxic effects of straight versus tangled multi-walled carbon nanotubes — J. Catalán, K.M. Siivola, et al. (2016)

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