Effects of mineral fibres in an in vitro placental syncytiotrophoblast model

Our plain-English summary of Effects of mineral fibres in an in vitro placental syncytiotrophoblast model, by G. Tossetta, S. Fantone, A.D. Procopio, et al (Current Research in Toxicology, 2025).

The study

• Authors: G. Tossetta, S. Fantone, A.D. Procopio, A. Pugnaloni, A.F. Gualtieri, D. Marzioni
• Journal: Current Research in Toxicology
• Published: 2025;8:100231
• Read it: PubMed · Publisher · Free full text

Abstract

It is known that mineral fibres can be found in placental tissues, but their effect is not known on these tissues. BeWo in vitro model of syncytiotrophoblast, the outer layer of maternal-foetal barrier, is necessary to understand if mineral fibres can alter placental cell turnover and consequently to influence the outcome of pregnancy. We performed in vitro experiments using chrysotile UICC (UICC), chrysotile Valmalenco (VM) and erionite (ERI) to investigate the potential cytotoxic effects of these mineral fibres on BeWo cells. We demonstrated that all fibres are toxic while only UICC fibres caused a DNA damage that the cells were not able to repair through RAD51 activity. In addition, we demonstrated that DNA replication is not altered while cyclin D1 showed a significant decrease in VM and UICC suggesting that the cell cycle is altered in G1 phase. Moreover, UICC increased active form of caspase 3 demonstrating that apoptosis can be induced in BeWo cells. We suggest that although morphological changes are not visible in BeWo cells treated with these mineral fibres, DNA damage can lead to altered placenta physiology that can be seen late when the damage at the foetal tissues has already occurred.

© 2025 The Author(s).

In plain English

This laboratory study exposed BeWo cells, a human cell line used to model the syncytiotrophoblast (the outer layer of the placenta that faces the mother's blood), to three mineral fibre samples. These were chrysotile from Valmalenco, Italy (VM), the UICC chrysotile standard (UICC) and fibrous erionite-Na (ERI). Each was added at 50 μg/ml for periods from 10 minutes to 48 hours. All three reduced cell viability: erionite from 30 minutes and both chrysotiles from 2 hours, with greater effect at longer times. None visibly changed the cells' appearance or their ability to fuse into a syncytium. All three raised a marker of DNA damage (γ-H2AX), most clearly UICC. Only UICC lowered the DNA-repair protein RAD51 and raised active caspase 3, a marker of programmed cell death. Cyclin D1 fell with VM and UICC. The authors concluded that the fibres can impair trophoblast cell development by inducing DNA damage. They called for studies of pregnancy complications in women exposed to asbestos. The work used cultured cells only, not people.

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 laboratory experiment on a cultured human cell line
• Who was studied: Human BeWo cells grown in culture as a model of placental syncytiotrophoblast. Each experiment was repeated three times (N = 3). No human subjects or animals were studied.
• Exposure: Chrysotile from Valmalenco, Italy (VM); UICC standard chrysotile (UICC); and fibrous erionite-Na from Jersey, Nevada, USA (ERI). Each was applied at 50 μg/ml for 10 min, 30 min, 2 h, 4 h, 8 h, 24 h and 48 h. Control cells received no fibres. The article groups all three samples under the heading of asbestos fibres.
• Main results:
  • Cell viability (MTT assay) fell significantly with ERI from 30 minutes, and with UICC and VM from 2 hours (N = 3).
  • Cytotoxicity increased with longer fibre contact time, up to 48 hours.
  • None of the fibres visibly changed BeWo cell morphology after 24 hours, and none altered syncytialization as measured by E-cadherin (N = 3).
  • The DNA-damage marker γ-H2AX increased with all three fibres, most markedly with UICC (p less than 0.001).
  • Expression of the DNA-repair protein RAD51 decreased significantly only with UICC (N = 3). The authors interpreted this as the cells being unable to repair UICC-induced damage.
  • PCNA, a marker of DNA replication, was not changed by any fibre.
  • Cyclin D1 decreased significantly with VM (p = 0.005) and UICC (p = 0.023). The authors suggested the cell cycle could be altered in the G1 phase.
  • The cleaved (active) form of caspase 3, an apoptosis marker, increased significantly only with UICC.
• The authors' conclusion: The authors concluded that asbestos fibres can significantly impair trophoblast cell development by inducing DNA damage, and that only UICC chrysotile induced apoptosis. They attributed this difference apparently to the different sizes of the UICC and VM fibres, citing size measurements from earlier studies.
• Limitations the authors state:
  • The authors stated that further studies are needed to evaluate the relationship between asbestos fibres and pregnancy complications in women exposed to asbestos.
  • The authors noted that primary trophoblast cells or in vivo experiments in pregnant women would be the best model. They chose the BeWo cell line because they judged those alternatives to have greater limitations.
  • The authors noted that it is not clear how asbestos fibres reach placental tissue.

Topics

Medical terms in this study, explained in our Lexicon: Chrysotile, UICC, erionite, Apoptosis.

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