Pleural mesothelial cells stimulated by asbestos release chemotactic activity for neutrophils in vitro

Our plain-English summary of Pleural mesothelial cells stimulated by asbestos release chemotactic activity for neutrophils in vitro, by V.B. Antony, C.L. Owen, K.J. Hadley (The American Review of Respiratory Disease, 1989).

The study

• Authors: V.B. Antony, C.L. Owen, K.J. Hadley
• Journal: The American Review of Respiratory Disease
• Published: 1989;139(1):199-206
• Cited by: 46 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The development of the pleural inflammatory response to asbestos remains poorly defined. Importantly, the role of the pleural mesothelial cell in recruitment of neutrophils to the pleural space is not known. We hypothesized that rabbit pleural mesothelial cells stimulated by asbestos fibers release chemotactic factor(s) for neutrophils. Primary cultures of rabbit pleural mesothelial cells were established, and their purity verified by the presence of keratin and hyaluronic acid mucin. Mesothelial cells in serum-free media, in the presence of 30 micrograms/ml of crocidolite asbestos, released chemotaxins for neutrophils. This activity was not dependent on the type of asbestos fiber or fiber length. It was dose-dependent until 30 micrograms/ml of asbestos. The chemotactic fractions had the ability to increase both directed and random migration of neutrophils. The chemotactic activity was not present in sonicated fractions of unstimulated mesothelial cells, nor in supernates of asbestos fibers alone. Characterization of the chemotactic activity showed that it was heat stable (56 degrees C per 30 min) and sensitive to digestion with trypsin and papain. On Sephadex G-50 chromatography, it had a molecular weight between 6,000 and 9,000. Production of the chemotactic activity was inhibitable by cycloheximide. These results demonstrate that pleural mesothelial cells can actively synthesize a protein fraction with chemotactic activity for neutrophils. Production of this mesothelial cell-derived chemotactic activity for neutrophils may play an important role in the initiation of the inflammatory response of the pleura to asbestos.

In plain English

This was a laboratory study of cells grown in dishes, not a study of people. The authors cultured pleural mesothelial cells (cells lining the chest cavity) from 16 rabbits and exposed them to crocidolite or chrysotile asbestos in serum-free medium. They then tested whether the surrounding fluid attracted neutrophils, a type of white blood cell, taken from normal human subjects. Fluid from asbestos-exposed mesothelial cells attracted significantly more neutrophils than medium alone, asbestos alone, or unexposed cells. At the same dose, crocidolite produced more of this activity than chrysotile. Long and short crocidolite fibers gave similar results. Asbestos-exposed fibroblasts, and mesothelial cells exposed to silica, did not produce significant activity. Tests indicated the attracting substance was a protein, with peak activity at a molecular weight around 8,000. Adding cycloheximide, a protein-synthesis blocker, before the asbestos significantly inhibited its production. The authors concluded that mesothelial cells can actively make this protein, and that it may play a role in starting the pleura's inflammatory response to asbestos. They noted their experiments did not establish whether the response is specific to asbestos.

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 using cultured rabbit pleural mesothelial cells
• Who was studied: Pleural mesothelial cells from 16 pathogen-free New Zealand white rabbits, used at culture passages 2 to 8; neutrophils for the attraction tests came from normal human subjects
• Exposure: Standard UICC crocidolite and chrysotile asbestos at zero to 60 µg/ml (main dose 30 µg/ml), including crocidolite sonicated until more than 95% of fibers were under 5 µm long; silica (30 µg/ml) was used as a comparison particle
• Main results:
  • Fluid from mesothelial cells incubated for 4 hours with 30 µg/ml crocidolite had significantly greater neutrophil-attracting activity than medium alone, asbestos alone, or mesothelial cells alone (p less than 0.05, n = 18 experiments)
  • At 30 µg/ml for 4 hours, crocidolite produced greater activity than chrysotile (p less than 0.05, n = 16)
  • Fiber length made no significant difference: crocidolite fibers over 5 µm gave 137 ± 5 neutrophils per 10 high-power fields, and sonicated crocidolite (95% of fibers under 5 µm) gave 144 ± 12
  • Maximal activity in fluid from asbestos-stimulated mesothelial cells was reached after 2 hours of incubation
  • Fluid from fibroblasts incubated with asbestos (22 ± 3 neutrophils per 10 high-power fields) and from mesothelial cells incubated with silica (28 ± 5) did not contain significant activity
  • Ruptured and sonicated unstimulated mesothelial cells did not contain significant activity (14 ± 6 neutrophils per 10 high-power fields)
  • Asbestos doses above 30 µg/ml increased release of lactic dehydrogenase from mesothelial cells, a sign of cell damage
  • The activity behaved as a protein: it was destroyed by trypsin and papain and was stable at 56°C for 30 seconds. Its peak eluted at a molecular weight around 8,000.
  • Cycloheximide added before asbestos significantly inhibited the activity (p less than 0.05, n = 8 experiments). Adding it at the end of incubation did not.
• The authors' conclusion: The authors concluded that pleural mesothelial cells can actively synthesize a protein fraction that attracts neutrophils, and that its production may play an important role in starting the pleura's inflammatory response to asbestos
• Limitations the authors state:
  • The authors stated their experiments do not define whether the mesothelial cell response is specific to asbestos fibers

Topics

Medical terms in this study, explained in our Lexicon: Mesothelial Cells, Hyaluronic Acid, Crocidolite, Fiber Length, Pleura.

Related studies

• Neutrophil chemotactic factor release and neutrophil alveolitis in asbestos-exposed individuals — A.A. Hayes, A.H. Rose, et al. (1988)
• Asbestos-induced release of a human alveolar macrophage-derived neutrophil chemotactic factor — A.A. Hayes, T.J. Venaille, et al. (1990)
• Interleukin-1-mediated release of interleukin-8 by asbestos-stimulated human pleural mesothelial cells — D.E. Griffith, E.J. Miller, et al. (1994)
• In vitro biodegradation of chrysotile fibres by alveolar macrophages and mesothelial cells in culture: comparison with a pH effect — M.C. Jaurand, A. Gaudichet, et al. (1984)
• Time course of chemotactic factor generation and the corresponding macrophage response to asbestos inhalation — D.B. Warheit, L.H. Hill, et al. (1986)
• Chemotactic factor generation by asbestos. Fibre type differences and the effects of leaching — E. Yano, A. Takeuch, et al. (1984)

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