Phagocytosis of chrysotile fibers by pleural mesothelial cells in culture

Our plain-English summary of Phagocytosis of chrysotile fibers by pleural mesothelial cells in culture, by M.C. Jaurand, H. Kaplan, J. Thiollet, et al (The American Journal of Pathology, 1979).

The study

• Authors: M.C. Jaurand, H. Kaplan, J. Thiollet, M.C. Pinchon, J.F. Bernaudin, J. Bignon
• Journal: The American Journal of Pathology
• Published: 1979;94(3):529-38
• Cited by: 50 articles, as counted by NIH iCite
• Read it: PubMed · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy.

Abstract

Pleural mesothelial cells (PMC) from the parietal pleura of rats were incubated in culture with UICC A chrysotile fibers. The sequence of events in phagocytosis was studied by electron microscopy: phases of attachment sequestration, and degranulation of lysosomal content into the phagocytic vacuole were observed. This demonstrates that PMC can engage in phagocytosis of chrysotile fibers.

In plain English

In this laboratory experiment, the authors grew mesothelial cells taken from the parietal pleura (the lining of the chest wall) of two-month-old Wistar rats. They exposed 15-day-old cultures to UICC A chrysotile fibers for 15 minutes, 45 minutes or 4 hours. They examined the cells by electron microscopy, using a stain for the enzyme acid phosphatase to mark lysosomes, the cell's digestive compartments. After 15 minutes, in some cells, fibers touched the cell surface or lay in folds of the membrane. After 45 minutes, more fibers were inside the cells, enclosed in membrane-bound sacs, some of which showed enzyme staining. After 4 hours, many fibers were inside the cells, staining very close to them was intense, and the rest of the cell structure looked well preserved. The authors concluded that these cells can engage in phagocytosis (engulfing) of chrysotile fibers. They suggested that the release of lysosome contents into the sac (vacuole) containing the fibers may be an early step in the cell-damaging and cancer-causing action of asbestos. They noted that movement of cells toward particles could not be observed in this setup. The article does not say how many rats or cells were examined.

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: laboratory (in vitro) experiment on cultured rat cells, examined by electron microscopy and acid phosphatase cytochemistry
• Who was studied: Mesothelial cells isolated from the parietal pleura of two-month-old Wistar rats, grown as primary cultures and used at 15 days old; laboratory in Creteil, France; number of rats or cells not stated
• Exposure: UICC A chrysotile fibers added to the culture dishes at a concentration printed as "100 gg X ml 1" (unit garbled in the scan), left for 15 minutes, 45 minutes or 4 hours; mean fiber length printed as "< 4g" (unit garbled)
• Main results:
  • After 15 minutes, in some cells, fibers were in contact with cell membranes or within invaginations of the membrane; lysosomes were unchanged and distant from the fibers
  • After 45 minutes, more fibers were in the cells, inside membrane-bound structures
  • At 45 minutes the acid phosphatase reaction inside the phagosomes was generally negative, but some showed a positive reaction, indicating phagolysosomes
  • By 4 hours, many fibers were seen inside the cytoplasm, apparently inside phagocytic vacuoles, with intense acid phosphatase staining very close to the fibers
  • At 4 hours primary lysosomes were rarely observed
  • Four hours after incubation with chrysotile, the ultrastructure of the cells was still well preserved
• The authors' conclusion: The authors concluded that pleural mesothelial cells can engage in phagocytosis of chrysotile fibers, by a process similar to that for other particles. They suggested that the degranulation phase (release of lysosomal granules into the phagocytic vacuole) may be a preliminary step in the cytolytic and carcinogenic action of asbestos fibers.
• Limitations the authors state:
  • Under in vitro conditions and with closely bound cells, the authors could not observe chemotaxis (the first phase of phagocytosis)

Topics

Medical terms in this study, explained in our Lexicon: Phagocytosis, Chrysotile, Mesothelial Cells, Parietal Pleura, UICC.

Related studies

• The interactions between asbestos fibers and metaphase chromosomes of rat pleural mesothelial cells in culture. A scanning and transmission electron microscopic study — N.S. Wang, M.C. Jaurand, et al. (1987)
• Vitronectin adsorption to chrysotile asbestos increases fiber phagocytosis and toxicity for mesothelial cells — J. Wu, W. Liu, et al. (2000)
• 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)
• Analysis of cell cycle disruptions in cultures of rat pleural mesothelial cells exposed to asbestos fibers — V. Levresse, A. Renier, et al. (1997)
• Phagocytosis of crocidolite asbestos induces oxidative stress, DNA damage, and apoptosis in mesothelial cells — W. Liu, J.D. Ernst, et al. (2000)
• Asbestos-induced endothelial cell activation and injury. Demonstration of fiber phagocytosis and oxidant-dependent toxicity — J.G. Garcia, L.D. Gray, et al. (1988)

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