What's new in intraperitoneal test on Kevlar (asbestos substitute)?

Our plain-English summary of What's new in intraperitoneal test on Kevlar (asbestos substitute)?, by O.A. Brinkmann, K.M. Müller (Pathology, Research and Practice, 1989).

The study

• Authors: O.A. Brinkmann, K.M. Müller
• Journal: Pathology, Research and Practice
• Published: 1989;185(3):412-7
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The intraperitoneal test is a suitable experimental method for studying the different patterns of morphological reaction to foreign body substances of various kinds and concentrations as well as their transport within and elimination from the organism, Kevlar fibres are synthetic aromatic polyamid (aramid) fibres which, investigated by means of the intraperitoneal test in Wistar rats, show distinct pathogenetic reaction patterns: 1. In the early stage after application, the formation of multinucleated giant cells with phagocytosis of the amber-coloured Kevlar fibres, and an inflammatory reaction are foremost features. 2. The typical feature of the second stage is the development of granulomas with central necrosis indicating the cytotoxic nature of Kevlar fibres. 3. The third stage is dominated by the mesenchymal activation with capsular structures of collagenous fibres. Besides granulomatous foci, a slight submesothelial fibrosis is observed. 4. Fragments of Kevlar fibres are drained through lymphatic pathways and stored in lymph nodes where they lead to inflammatory reactions. 5. The reactive granulomatous changes in the greater omentum of rats are accompanied by proliferative mesothelial changes which, in one cases, even led to the development of a multilocular mesothelioma.

In plain English

This was an animal experiment by pathologists in Bochum, West Germany, on how tissue reacts to Kevlar, a synthetic aramid fibre used as an asbestos substitute in protective garments, tyre casings and brake linings. Kevlar fibres in saline were injected into the abdominal cavity of eight-week-old Wistar rats weekly for 4 weeks. The rats were killed 28 months after the first injection, and the omentum (a fold of the abdominal lining) and nearby lymph nodes were examined under light and scanning electron microscopes. The report was based on two animals. Kevlar fibres persisted, forming granulomas (walled-off inflammatory nodules) up to 3 mm across, most with dead tissue at the centre. There was also some scarring beneath the lining. Fibre fragments carried by scavenger cells reached the lymph nodes. In one case, lining cells had grown into an invasive mesothelioma of the abdominal lining. The authors said the reaction resembled that to glass or asbestos fibres and was not specific to Kevlar. They could not establish a direct connection between the tumour growth and the fibres. They concluded that the results supported the idea that malignant tumours develop in steps after exposure to fibrous dusts.

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 (intraperitoneal injection test in rats), short 'What's New' report
• Who was studied: Eight-week-old Wistar rats. The report was based on two animals exposed to Kevlar fibres. Specimens came from Bochum, West Germany.
• Exposure: Kevlar (para-aramid, a synthetic organic fibre) suspended in 1 ml physiological saline, injected into the abdominal cavity weekly for 4 weeks. The printed dose is garbled ('S mg'). Rats were killed 28 months after the first injection.
• Main results:
  • Kevlar fibres persisted in the omentum, with a granulomatous foreign-body reaction and multinucleated giant cells over at least 28 months
  • Most granulomas (up to 3 mm in diameter) had partial or total central necrosis, which the authors read as suggesting a cytotoxic effect of Kevlar
  • Submesothelial fibrosis was found in 'turbid' parts of the omentum
  • Kevlar fragments taken up by macrophages were found in lymph nodes draining the omentum, with inflammatory changes there
  • In one case, papillary mesothelial proliferation invaded adjacent tissue, which the authors described as reaching the stage of invasive mesothelioma of the omentum
  • The reaction resembled that seen after injection of glass or asbestos fibres and showed no pattern specific to Kevlar
• The authors' conclusion: The authors concluded that the results confirm the hypothesis that malignant tumours develop stepwise after exposure to fibrous dusts, through inflammatory-granulomatous, fibrogenic and ultimately neoplastic stages.
• Limitations the authors state:
  • In the tumour areas, the authors could not establish a direct connection between the tumour growth and the injected agents

Topics

Medical terms in this study, explained in our Lexicon: Phagocytosis, Granuloma, Necrosis, Fibrosis, Omentum, Mesothelioma.

Related studies

• Giant cell formation after intraperitoneal application of crocidolite asbestos fibres in rats — S. Sethi, E.G. Beck, et al. (1974)
• Comparative hazards of chrysotile asbestos and its substitutes: A European perspective — P.T. Harrison, L.S. Levy, et al. (1999)
• Man-made respirable-sized organic fibers: what do we know about their toxicological profiles? — D.B. Warheit, K.L. Reed, et al. (2001)
• Experimentally induced mesothelioma in white rats in response to intraperitoneal administration of amorphous crocidolite asbestos: preliminary report — K. Kolev (1982)
• Detection of mineral fibre carcinogenicity with the intraperitoneal test--recent results and their validity — F. Pott (1995)
• Tissue response to intraperitoneal asbestos with preliminary report of acute toxicity of heart-treated asbestos in mice — J. Jagatic, M.E. Rubnitz, et al. (1967)

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