Pluripotential nature of mesotheliomata induced by inhalation of erionite in rats

Our plain-English summary of Pluripotential nature of mesotheliomata induced by inhalation of erionite in rats, by N.F. Johnson, R.E. Edwards, D.E. Munday, et al (British Journal of Experimental Pathology, 1984).

The study

• Authors: N.F. Johnson, R.E. Edwards, D.E. Munday, N. Rowe, J.C. Wagner
• Journal: British Journal of Experimental Pathology
• Published: 1984;65(3):377-88
• Cited by: 20 articles, as counted by NIH iCite
• Read it: PubMed · Free full text

Abstract

Mesotheliomata can be induced more rapidly and more frequently by inhalation of erionite than by asbestos inhalation. Erionite-induced tumours have in general a similar ultrastructural appearance to inoculum-induced pleural and peritoneal mesotheliomata. Unusual features of these tumours were the presence of dense-cored vesicles and cells staining positively for neuron-specific enolase which indicated the presence of endocrine cells. In addition, one tumour showed differentiation towards bone-forming cells. The expression of both epithelial and mesodermal characteristics demonstrates the pluripotential nature of mesothelial cells under certain circumstances.

In plain English

This was an animal pathology study. The authors examined pleural tumours (mesotheliomata) from seven rats that had breathed erionite, a fibrous zeolite mineral from Oregon, USA, for 12 months, 7 hours a day, 5 days a week. They used light and electron microscopy and chemical and antibody stains. The paper's statement that erionite causes these tumours faster and more often than asbestos refers to earlier work the authors cite, not to these seven rats. The tumours were epithelial, fibrosarcomatous or mixed, and most were mixed. Epithelial-like cells stained for keratin, and spindle cells stained less intensely. Two tumours stained positively for neuron-specific enolase, and dense-cored vesicles were commonly seen. The authors took these as signs of endocrine cells. One tumour formed bone-like material. The authors judged the tumours similar to other experimentally induced mesotheliomata. They concluded that the mix of epithelial and mesodermal features showed the pluripotential nature of mesothelial cells, meaning the cells can develop along several lines. They noted that fixation may not have preserved hyaluronic acid well.

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; pathology study (light microscopy, electron microscopy, histochemistry and immunohistochemistry) of tumours from rats exposed by inhalation
• Who was studied: pleural tumours from seven rats exposed to erionite by inhalation
• Exposure: inhalation of erionite (a fibrous zeolite mineral) from Rome, Oregon, USA, for 12 months, 7 hours a day, 5 days a week; the concentration is printed in the scanned text as 'Io mg/m3', which cannot be read with certainty
• Main results:
  • In these seven rat tumours, the forms were epithelial, fibrosarcomatous or mixed; most were mixed, with either the fibrous or the epithelial part more prominent
  • In keratin staining, spindle cells generally stained less intensely than epithelial-like cells
  • Two of the seven tumours stained positively for neuron-specific enolase
  • Dense-cored vesicles were commonly seen in epithelial-like tumour cells; together with the neuron-specific enolase staining, the authors took this to indicate endocrine cells
  • One tumour (case no. 6) formed bone trabeculae and had lipid-rich cells
  • In that tumour, there was a gradual transition from osteoblast-like cells to typical mesothelial cells on the tumour surface
  • In six of the seven cases, traces of hyaluronic acid were seen in some intracellular vacuoles
  • The authors judged the range of tumour appearances similar to other experimentally induced mesotheliomata
• The authors' conclusion: The authors concluded that the tumours' expression of both epithelial and mesodermal characteristics demonstrates that mesothelial cells can be pluripotential under certain circumstances
• Limitations the authors state:
  • The initial fixation may not have been fully adequate to preserve hyaluronic acid
  • The relative expression of features such as intracytoplasmic microfibrils and dense-cored vesicles was difficult to compare across tumours

Topics

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

Medical terms in this study, explained in our Lexicon: erionite, Mesothelial Cells.

Related studies

• Erionite exposure and mesotheliomas in rats — J.C. Wagner, J.W. Skidmore, et al. (1985)
• In vitro genotoxic activities of fibrous erionite — A. Poole, R.C. Brown, et al. (1983)
• Mesotheliomas induced in rats by the fibrous mineral erionite are independent from p53 alterations — E.V. Kleymenova, G. Horesovsky, et al. (1999)
• Mesotheliomata in rats after inoculation with asbestos and other materials — J.C. Wagner, G. Berry, et al. (1973)
• Fiber-induced hydroxyl radical formation: correlation with mesothelioma induction in rats and humans — K.R. Maples, N.F. Johnson (1992)
• The in vitro genetic effects of fibrous erionite and crocidolite asbestos — K.T. Kelsey, E. Yano, et al. (1986)

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