Effects of the new-identified amphibole fluoro-edenite in lung epithelial cells

Our plain-English summary of Effects of the new-identified amphibole fluoro-edenite in lung epithelial cells, by S. Travaglione, B. Bruni, L. Falzano, et al (Toxicology in Vitro, 2003).

The study

• Authors: S. Travaglione, B. Bruni, L. Falzano, L. Paoletti, C. Fiorentini
• Journal: Toxicology in Vitro
• Published: 2003;17(5-6):547-52
• Cited by: 18 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

An epidemiological survey on mortality for malignant pleural neoplasm in Italy evidenced a number of patients in Biancavilla, a village located in a volcanic area of eastern Sicily, none of which had been significantly exposed to asbestos during their professional lives. Environmental studies suggested the involvement of the material derived from stone quarries in the disease onset. A detailed crystal-chemical analysis of amphiboles contained in this material allowed the discovery and the identification of a new fiber that was named fluoro-edenite. In order to define the mode of action of fluoro-edenite at a subcellular level, we have conducted a study by using A549 cells, a tumor-cell line from a human lung carcinoma with properties of alveolar epithelial cells. The results obtained showed a remarkable tropism of A549 cells toward fluoro-edenite fibers. In fact, these epithelial cells contacted the fibers via the extension of membrane ruffles and filopodia that allowed the capture and most probably the internalization of material into the cytoplasm. Moreover, fluoro-edenite interfered with epithelial cell physiology, by reducing the proliferation rate without perturbing the cell cycle and increasing the release of the proinflammatory cytokine IL-6, one of the main mediators of asbestos-induced pathophysiological response.

In plain English

This was a laboratory study of human lung cells grown in dishes, not a study of people. The authors exposed A549 cells, a human lung tumor cell line, to fluoro-edenite, a newly identified amphibole mineral from lava stone at Monte Calvario near Biancavilla, Sicily. Cells received three concentrations (printed as 1, 5 and 50 mg/ml) for 24, 48 or 72 hours. Under the electron microscope, the cells reached toward the fibers with membrane extensions called ruffles and filopodia and wrapped around them. The authors suggested the cells probably took the fibers inside. The cells' internal actin framework was not changed, and the cells' passage through the phases of the cell cycle was not affected, but the cells multiplied more slowly. Treated cells released more of the inflammatory signal IL-6 over time, most clearly at 72 hours. The authors concluded that their data link fluoro-edenite exposure to certain cellular changes. They added that more work is needed to establish a role for the fiber in lung disease 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: Laboratory (in vitro) cell-culture experiment
• Who was studied: A549 cells, a tumor cell line from a human lung carcinoma with properties of alveolar (type-II like) epithelial cells; no human subjects
• Exposure: Fluoro-edenite, a new amphibole extracted as prismatic crystals from benmoreitic lava at Monte Calvario (Biancavilla, Sicily), ground in an agate mill. Cells were exposed 24 hours after seeding at three concentrations printed as 1, 5 and 50 mg/ml, for 24, 48 and 72 hours.
• Main results:
  • Under scanning electron microscopy, the lung epithelial cells showed a marked attraction (tropism) toward the fluoro-edenite fibers.
  • The cells extended membrane ruffles and filopodia that contacted and wrapped around the fibers. The authors suggested this could lead to the fibers being engulfed into the cell's cytoplasm.
  • The actin cytoskeleton (the cell's internal framework) was unchanged in treated cells compared with control cells.
  • Exposure did not change how cells passed through the phases of the cell cycle, but it reduced the cells' capacity to proliferate.
  • Fluoro-edenite treatment led to IL-6 secretion by the cells in a time-dependent way, with the clearest difference at 72 hours. Numerical values are shown only in a figure.
• The authors' conclusion: The authors concluded that their data show a link between fluoro-edenite exposure and certain cellular alterations of the kind caused by airborne particles known to damage lung cells.
• Limitations the authors state:
  • The authors stated that further work is needed to establish whether this fiber plays a role in the onset of lung disease in Biancavilla.

Topics

Medical terms in this study, explained in our Lexicon: Amphibole Group, fluoro-edenite, Neoplasm, Biancavilla, Discovery, A549 Cells, Carcinoma, Cytokine.

Related studies

• 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)
• Multinucleation and pro-inflammatory cytokine release promoted by fibrous fluoro-edenite in lung epithelial A549 cells — S. Travaglione, B.M. Bruni, et al. (2006)
• Pleural mesothelioma cases in Biancavilla are related to a new fluoro-edenite fibrous amphibole — P. Comba, A. Gianfagna, et al. (2003)
• In vitro determinants of asbestos fiber toxicity: effect on the relative toxicity of Libby amphibole in primary human airway epithelial cells — K.E. Duncan, P.M. Cook, et al. (2014)
• Asbestos causes apoptosis in alveolar epithelial cells: role of iron-induced free radicals — A. Aljandali, H. Pollack, et al. (2001)
• Differential activation of the inflammasome in THP-1 cells exposed to chrysotile asbestos and Libby "six-mix" amphiboles and subsequent activation of BEAS-2B cells — M. Li, M.E. Gunter, et al. (2012)

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