Metsovo-tremolite asbestos fibres: in vitro effects on mutation, chromosome aberration, cell transformation and intercellular communication

Our plain-English summary of Metsovo-tremolite asbestos fibres: in vitro effects on mutation, chromosome aberration, cell transformation and intercellular communication, by K. Athanasiou, S.H. Constantopoulos, E. Rivedal, et al (Mutagenesis, 1992).

The study

• Authors: K. Athanasiou, S.H. Constantopoulos, E. Rivedal, D.J. Fitzgerald, H. Yamasaki
• Journal: Mutagenesis
• Published: 1992;7(5):343-7
• Cited by: 15 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Samples of Metsovo-tremolite asbestos, previously found to be the causative agent of endemic pleural calcification and an increased level of malignant pleural mesothelioma in a rural area of north-western Greece (Metsovo area), were tested in various in vitro toxicity test systems. It was found that asbestos fibres of this type were strong inducers of micronuclei and numerical chromosomal abnormalities while they induced low levels of chromosomal aberrations in mammalian cells in culture. Furthermore, this type of asbestos can induce a low level of in vitro transformation of Syrian hamster embryo cells. The fibres had no effect on gap-junctional cell-cell communication (followed by the dye-transfer method) and did not induce any mutations in the Salmonella typhimurium strain TA102 which is known to be sensitive to the action of various oxidative agents. These results support the hypothesis generated from studies on other types of asbestos that such fibres induce tumours by causing chromosomal mutations.

In plain English

This laboratory study tested tremolite asbestos fibres from the Metsovo area of north-western Greece on animal cells grown in culture and on bacteria. Earlier work had linked this tremolite to pleural calcification and malignant pleural mesothelioma in the area. The fibres were up to 10 micrometres long. In hamster BPNi cells, micronuclei (small extra nuclei, a sign of chromosome damage) rose with dose, from 17 per 1000 untreated cells to 205 per 1000 at 2.0 micrograms per square centimetre. In Syrian hamster embryo cells, the share of cells with an abnormal chromosome number rose from 4% to 38%. Chromosome aberrations stayed low with no clear dose pattern, but all treated groups combined showed a statistically significant increase over untreated cells. Tremolite caused a low level of transformation, an abnormal change in colony growth, but the highest dose was severely toxic to the cells. The fibres did not affect communication between neighbouring cells and caused no mutations in three Salmonella bacterial strains. The authors concluded that the results support the idea that such fibres cause tumours by causing chromosomal mutations.

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) experiments on cultured animal cells and bacteria
• Who was studied: Cultured cells: Chinese hamster V79 cells, the Syrian hamster BPNi cell line and Syrian hamster embryo (SHE) cells, plus Salmonella typhimurium strains TA98, TA100 and TA102
• Exposure: Metsovo-tremolite asbestos fibres, up to 10 micrometres long with an average diameter of about 0.20 micrometres. Cell doses ranged from 0.3 to 4.0 micrograms per square centimetre depending on the test. Bacterial doses ranged from 10 to 500 micrograms per plate.
• Main results:
  • In BPNi cells treated for 24 hours, micronuclei rose with dose: 17 per 1000 cells in controls, 31 at 0.5, 70 at 1.0 and 205 at 2.0 micrograms per square centimetre. The increase was significant even at 0.5 micrograms per square centimetre.
  • In SHE cells, the percentage of aneuploid cells (abnormal chromosome number) was 4% in controls, 8% at 0.5, 16% at 1.0, 26% at 2.0 and 38% at 3.0 micrograms per square centimetre. Tetraploid or near-tetraploid cells rose from 4% to 18%. The authors report significant increases even at 0.5 micrograms per square centimetre.
  • In SHE cells, chromosome aberrations were low: 3% in controls and 4%, 12%, 9% and 13% at 0.5, 1.0, 2.0 and 3.0 micrograms per square centimetre. There was no clear dose-response. When all treated groups were combined, the increase over controls was statistically significant.
  • In SHE cells, morphological transformation was seen in 0 of 1193 colonies in controls (below 0.08%), 2 of 984 (0.20%) at 0.5, 4 of 679 (0.59%) at 1.0 and 5 of 199 (printed as 1.17%) at 2.0 micrograms per square centimetre. At 4.0 micrograms per square centimetre there was severe cytotoxicity (relative survival 6.03%) and no transformed colonies.
  • Tremolite did not inhibit gap-junctional communication between neighbouring cells in V79 or BPNi cells at any dose or treatment duration tested.
  • Tremolite caused no increase in revertant colonies (mutations) in Salmonella strains TA98 and TA100.
  • Tremolite was also inactive in Salmonella strain TA102, a strain sensitive to oxygen-radical-producing agents.
  • A preliminary test showed a slight increase in sister chromatid exchange frequency in SHE cells that was not dose-related. The data were not shown.
• The authors' conclusion: The authors concluded that the results support the hypothesis, drawn from studies of other asbestos types, that such fibres induce tumours by causing chromosomal mutations. They also wrote that the negative TA102 result and the marginal sister chromatid exchange increase argue against active oxygen species as the mechanism.

Topics

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

Medical terms in this study, explained in our Lexicon: Tremolite, Endemic, Pleural Calcification, Pleural Mesothelioma, Micronuclei.

Related studies

• Crocidolite induces cell transformation and p53 gene mutation in BALB/c-3T3 cells — F. Lin, Y. Liu, et al. (2000)
• Association of Metsovo lung and pleural mesothelioma with exposure to tremolite-containing whitewash — A.M. Langer, R.P. Nolan, et al. (1987)
• Chrysotile and rock wool fibers induce chromosome aberrations and DNA damage in V79 lung fibroblast cells — Y. Cui, J. Ma, et al. (2018)
• Biological effects of tremolite — J.C. Wagner, M. Chamberlain, et al. (1982)
• Expression of cell adhesion molecules and connexins in gap junctional intercellular communication deficient human mesothelioma tumour cell lines and communication competent primary mesothelial cells — K. Pelin, A. Hirvonen, et al. (1994)
• Role of fibre characteristics on cytotoxicity and induction of anaphase/telophase aberrations in rat pleural mesothelial cells in vitro: correlations with in vivo animal findings — M. Yegles, X. Janson, et al. (1995)

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