Behaviour of the new asbestos amphibole fluor-edenite in different lung cell systems

Our plain-English summary of Behaviour of the new asbestos amphibole fluor-edenite in different lung cell systems, by V. Cardile, M. Renis, C. Scifo, et al (The International Journal of Biochemistry & Cell Biology, 2004).

The study

• Authors: V. Cardile, M. Renis, C. Scifo, L. Lombardo, R. Gulino, B. Mancari, A. Panico
• Journal: The International Journal of Biochemistry & Cell Biology
• Published: 2004;36(5):849-60
• Cited by: 33 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The aim of the present research was to determine whether the recently identified and characterized new fibrous amphibole fluoro-edenite may induce a cytopathic response in cultured cells. The final goal was to gain suggestions on the potentiality of fluoro-edenite to be harmful to human beings. Epidemiological studies, in fact, have shown an excess of developing mesothelioma among residents in Biancavilla, a town in eastern Sicily located in the Etna volcanic area. Therefore, we treated human lung fibroblasts, human lung alveolar epithelial cancer cell line A549 and monocyte-macrophage cell line J774 with fluoro-edenite or crocidolite; the latter used as a highly toxic amphibole asbestos reference. Our results show that fluoro-edenite may induce functional modifications and affects some biochemical parameters in tested cell cultures in a concentration and time dependent manner. However, the observed functional modifications induced by fluoro-edenite are generally less dramatic than those induced by crocidolite and more evident on human lung alveolar epithelial cancer cell line A549 with respect to those obtained on human lung fibroblasts or monocyte-macrophage cell line J774. The sequence of the damage is hypothesised to be as follows: at increasing fluoro-edenite concentrations, and/or treatment times, the increase in reactive oxygen species (ROS) production could trigger significant DNA damage in cell cultures, concomitantly with drop in cell metabolism and increase in lactic dehydrogenase release. In conclusion, according to our data, fluoro-edenite appears as a probable carcinogenic agent, responsible for the high incidence of malignant pleural mesothelioma in Biancavilla.

In plain English

This laboratory study tested whether fluoro-edenite, a fibrous amphibole found in stone quarried near Biancavilla, Sicily, damages cells grown in culture. Other researchers had reported excess mesothelioma among residents there. The authors exposed normal human lung fibroblasts, a human lung cancer cell line (A549) and a mouse macrophage cell line (J774) to fluoro-edenite or to crocidolite, used as a reference asbestos. They tested three concentrations (5, 50 and 100 micrograms per millilitre) for 24, 48 or 72 hours. Fluoro-edenite lowered cell metabolism, increased leakage of the enzyme LDH (a sign of membrane damage), raised reactive oxygen species and increased DNA damage. The effects grew with concentration and time. In A549 cells after 72 hours at the highest concentration, LDH release was 52% with fluoro-edenite and 88% with crocidolite, against 14% in untreated cells. Effects were generally less marked than with crocidolite, and A549 cells appeared most sensitive. Unlike crocidolite, fluoro-edenite did not change nitric oxide levels. The authors concluded that fluoro-edenite appears to be a probable carcinogenic agent responsible for the high pleural mesothelioma incidence in Biancavilla.

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: In vitro cell culture experiment comparing fluoro-edenite with crocidolite at three concentrations and three exposure times
• Who was studied: Three cell types were studied: normal human adult lung fibroblasts (primary lines), the human lung alveolar epithelial cancer cell line A549, and the mouse monocyte-macrophage cell line J774. Each experiment was repeated at least three times in quadruplicate. No people or animals were studied.
• Exposure: Fluoro-edenite fibers from Biancavilla and crocidolite (OSHA standard) were suspended in culture medium. They were added at 5, 50 and 100 micrograms per millilitre for 24, 48 and 72 h. The micro prefix is lost in the text, which prints 'g/ml'.
• Main results:
  • Fluoro-edenite at 50 or 100 micrograms per millilitre drastically reduced the cells' ability to metabolize tetrazolium salts (a measure of cell viability, MTT assay) at 24, 48 and 72 h. At 5 micrograms per millilitre the interference was moderate.
  • Crocidolite caused a more drastic reduction in cell viability than fluoro-edenite at all three concentrations and times.
  • In A549 cells exposed to 100 micrograms per millilitre fluoro-edenite, LDH release was 29 ± 2.5% at 24 h, 38 ± 4.5% at 48 h and 52 ± 4.6% at 72 h.
  • In A549 cells exposed to 100 micrograms per millilitre crocidolite, LDH release was 52 ± 9.1% at 24 h, 58 ± 5.6% at 48 h and 88 ± 6.0% at 72 h.
  • In untreated A549 control cells, LDH release was 9 ± 1.8% at 24 h, 11 ± 1.0% at 48 h and 14 ± 2.2% at 72 h.
  • In all cell cultures, 24 h of treatment with 50 micrograms per millilitre fluoro-edenite or crocidolite was enough to significantly increase reactive oxygen species production.
  • Crocidolite increased nitric oxide synthesis and iNOS expression. Fluoro-edenite did not change nitric oxide levels under the study conditions. The data were not shown.
  • In the Comet assay on A549 cells after 72 h with 100 micrograms per millilitre fluoro-edenite, fragmented DNA (TDNA) was 71 ± 8.7%. Moderate DNA damage was seen at 5 micrograms per millilitre, and damage was much more dramatic at high concentrations.
  • Effects of fluoro-edenite were generally less dramatic than those of crocidolite, on a per weight basis.
  • A549 cells appeared more sensitive than the other cell types to the effects of both fluoro-edenite and crocidolite.
• The authors' conclusion: The authors concluded that, according to their data, fluoro-edenite appears to be a probable carcinogenic agent, responsible for the high incidence of malignant pleural mesothelioma in Biancavilla. They hypothesised that rising reactive oxygen species could trigger DNA damage.

Topics

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

Medical terms in this study, explained in our Lexicon: Amphibole Group, Edenite, fluoro-edenite, Mesothelioma, Biancavilla, Fibroblast, Macrophage, Crocidolite.

Related studies

• Fluoro-edenite fibers induce expression of Hsp70 and inflammatory response — V. Cardile, L. Lombardo, et al. (2007)
• A comparison of acute and long-term effects of industrial multiwalled carbon nanotubes on human lung and immune cells in vitro — T. Thurnherr, C. Brandenberger, et al. (2011)
• Multinucleation and pro-inflammatory cytokine release promoted by fibrous fluoro-edenite in lung epithelial A549 cells — S. Travaglione, B.M. Bruni, et al. (2006)
• Modulation of DNA single-strand breaks by intracellular glutathione in human lung cells exposed to asbestos fibers — A. Puhakka, T. Ollikainen, et al. (2002)
• Mineral fibre toxicity: expression of retinoblastoma (Rb) and phospho-retinoblastoma (pRb) protein in alveolar epithelial and mesothelial cell lines exposed to fluoro-edenite fibres — G. Musumeci, V. Cardile, et al. (2011)
• Angiogenesis correlates with macrophage and mast cell infiltration in lung tissue of animals exposed to fluoro-edenite fibers — G. Musumeci, C. Loreto, et al. (2016)

Browse more research in The International Journal of Biochemistry & Cell Biology, or return to medical research.