Erionite exposure and mesotheliomas in rats

Our plain-English summary of Erionite exposure and mesotheliomas in rats, by J.C. Wagner, J.W. Skidmore, R.J. Hill, et al (British Journal of Cancer, 1985).

The study

• Authors: J.C. Wagner, J.W. Skidmore, R.J. Hill, D.M. Griffiths
• Journal: British Journal of Cancer
• Published: 1985;51(5):727-30
• Cited by: 154 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Epidemiological and environmental surveys in the Cappadocian region of Turkey have linked the high incidence of pleural and peritoneal mesothelioma in the occupants of some villages with the zeolite fibres released from the locally occurring volcanic tuff. In view of the low ambient fibre concentrations and the extraordinary incidence of mesothelioma a study to test the hypothesis of high biological activity for the zeolite fibres was required. Experimental studies using both intrapleural inoculation and inhalation techniques have been undertaken with the erionite from this region and from Oregon in the United States. Additionally a non-fibrous zeolite from Japan and a synthetic non-fibrous zeolite of similar chemical composition to erionite have been included in the experiments. In these studies the samples from Oregon and Turkey produced a very high incidence of tumours. All the rats inoculated intrapleurally with Oregon erionite and almost all those inoculated with the Turkish fibre died with a mesothelioma. Inhalation of the Oregon erionite induced a similar effect. No other dusts we have investigated have produced this high incidence of tumours particularly following inhalation. These studies demonstrate that we now have a valuable new fibre for experimental study and a possible hazard to man in regions other then Turkey.

In plain English

This animal experiment tested erionite, a zeolite fibre linked to mesotheliomas in villages of Cappadocia, Turkey. Fischer 344 rats had dust injected into the chest cavity or breathed dust for one year. In the injection experiment, groups of 40 rats received 20 mg of Oregon (USA) erionite, rock fibre from the Turkish village of Karain, a non-fibrous Japanese zeolite or chrysotile asbestos; a control group received saline alone. Mesothelioma developed in 40 of 40 Oregon erionite rats, 38 of 40 Karain rats, 19 of 40 chrysotile rats, 2 of 40 non-fibrous zeolite rats and 1 of 40 saline rats. Mean survival of rats with mesothelioma was 390 and 435 days for the two erionites, against 678 days for chrysotile. In the inhalation experiment, 27 of 28 Oregon erionite rats surviving beyond 12 months developed mesothelioma. None did among crocidolite-exposed or unexposed rats, and one did among rats breathing synthetic non-fibrous zeolite. The authors concluded that erionite was a new fibre for experimental study and a possible hazard to people in regions other than Turkey.

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: Animal experiment (intrapleural inoculation and inhalation studies in rats)
• Who was studied: Fischer 344 barrier-maintained rats at the Medical Research Council Pneumoconiosis Unit, Penarth, Wales. Intrapleural experiment: 200 rats (100 males, 100 females) in 5 groups of 20 males and 20 females, inoculated at about 60 days of age. Inhalation experiment: 4 groups of 20 males and 20 females each, except the crocidolite group (16 males, 19 females), first exposed at about 57 days of age.
• Exposure: Intrapleural: 20 mg of Oregon erionite, Turkish (Karain) rock fibre, non-fibrous (Japanese) zeolite or chrysotile (positive control). A fifth group received saline, the vehicle, and no dose is stated for it. Inhalation: Oregon erionite, non-fibrous synthetic erionite or UICC crocidolite at a mean respirable dust concentration of 10 mg per cubic metre, 7 hours a day, 5 days a week, for one year; a fourth group was unexposed. The Karain sample came from a cave next to the home of a family in which several mesotheliomas had occurred.
• Main results:
  • Intrapleural: all 40 rats given Oregon erionite died with mesothelioma (mean survival 390 days).
  • Intrapleural: 38 of 40 rats given Karain rock fibre developed mesothelioma (mean survival 435 days).
  • Intrapleural: the chrysotile group had 19 mesotheliomas out of 40, and the saline group had 1 out of 40.
  • Intrapleural: the non-fibrous zeolite group had 2 mesotheliomas out of 40, one of them peritoneal.
  • Intrapleural: average time from inoculation to death from mesothelioma was 678 days for chrysotile, compared with 390 days for Oregon erionite and 435 days for Karain rock fibre.
  • Inhalation: 27 of 28 rats exposed to Oregon erionite and surviving more than 12 months developed mesothelioma, occurring between 385 and 800 days (average 580 days); 12 other animals had been sacrificed earlier to study dust accumulation.
  • Inhalation: in the crocidolite group (28 rats), no mesothelioma occurred, but one squamous carcinoma of the lung was observed.
  • Inhalation: in the synthetic non-fibrous zeolite group (28 rats) there was one mesothelioma and one adenocarcinoma; the unexposed control group (28 rats) had no tumours.
• The authors' conclusion: The authors concluded that the studies showed erionite to be a new fibre for experimental study and a possible hazard to people in regions other than Turkey. They also wrote that erionite's greater potential to induce mesothelioma compared with crocidolite, despite similar fibre sizes, pointed to additional properties of erionite worth further investigation.

Topics

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

Medical terms in this study, explained in our Lexicon: erionite, Mesothelioma, Peritoneal Mesothelioma, Zeolite.

Related studies

• Pluripotential nature of mesotheliomata induced by inhalation of erionite in rats — N.F. Johnson, R.E. Edwards, et al. (1984)
• In vitro genotoxic activities of fibrous erionite — A. Poole, R.C. Brown, et al. (1983)
• Metaphase and anaphase analysis of V79 cells exposed to erionite, UICC chrysotile and UICC crocidolite — L.D. Palekar, J.F. Eyre, et al. (1987)
• The in vitro genetic effects of fibrous erionite and crocidolite asbestos — K.T. Kelsey, E. Yano, et al. (1986)
• Assessment of asbestos body formation by high resolution FEG-SEM after exposure of Sprague-Dawley rats to chrysotile, crocidolite, or erionite — N.B. Gandolfi, A.F. Gualtieri, et al. (2016)
• Malignant pleural mesothelioma caused by environmental exposure to asbestos or erionite in rural Turkey: CT findings in 84 patients — A.A. Sahin, L. Cöplü, et al. (1993)

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