Leaching of chrysotile asbestos in human lungs. Correlation with in vitro studies using rabbit alveolar macrophages

Our plain-English summary of Leaching of chrysotile asbestos in human lungs. Correlation with in vitro studies using rabbit alveolar macrophages, by M.C. Jaurand, J. Bignon, P. Sebastien, et al (Environmental Research, 1977).

The study

• Authors: M.C. Jaurand, J. Bignon, P. Sebastien, J. Goni
• Journal: Environmental Research
• Published: 1977;14(2):245-54
• Cited by: 94 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The chemical microanalysis of chrysotile fibers obtained from human lungs and from chrysotile phagocytosed in vitro by rabbit alveolar macrophages (AM) was carried out with the use of an energy dispersive spectrometer mounted on a scanning electron microscope (SEM). This microanalysis was compared to natural fibers in order to investigate the chemical stability of chrysotile in biologic residence. The Mg versus Si content was estimated by the ratio of the peaks intensity Si:Mg. Lung samples were obtained from workmen with definite asbestos exposure, and chrysotile asbestos was extracted by chemical digestion. Phagocytosed chrysotile fibers were obtained after incubating standard chrysotile (AWCC) with rabbit alveolar macrophages for 24 hours or 5 days. Both chrysotile fibers from human lungs and from in vitro incubation with AM have shown an increase of the Si:Mg ratio in respect to standard fibers. Moreover, the results have shown that the magnesium leakage was not constant along the fiber axis and was different from one fiber to another.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This French laboratory study examined whether chrysotile asbestos fibers change chemically inside the body. Using an electron microscope with an X-ray analyzer, the authors measured the silicon-to-magnesium (Si:Mg) ratio of fibers. A higher ratio indicates magnesium has been lost. They studied fibers recovered from three patients with definite asbestos exposure and compared them with untreated chrysotile from Thetford mines and UICC chrysotile A. They also exposed UICC chrysotile A to rabbit alveolar macrophages (lung scavenger cells) for 24 hours or 5 days. The chemicals used to extract fibers did not change the ratio. Fibers from human lungs had higher ratios than control fibers, the ratio varied along a single fiber, and in some coated fibers magnesium was no longer detectable. Fibers taken up by rabbit macrophages also had higher ratios (5.40 to 9.37 after 24 hours; 3.91 to 5.11 after 5 days) than fibers kept in culture medium without cells (1.78 to 2.88). The authors suggested that products of cell metabolism may account for this magnesium loss, and that uneven loss may change how a fiber reacts along its length.

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 study: chemical microanalysis (scanning electron microscope with energy dispersive spectrometer) of chrysotile fibers recovered from human lungs, compared with an in vitro experiment in which rabbit alveolar macrophages took up chrysotile
• Who was studied: Three patients exposed to asbestos at work. Sixteen lung tissue samples were digested, with 10 coated and uncoated fibers analyzed per sample. Table 2 (as scanned) lists case 1 as female, aged 39, and cases 2 and 3 as males aged 68 and 38. Fiber counts for case 3 were made in sputum. The study also used alveolar macrophages obtained by lung lavage from anesthetized rabbits.
• Exposure: Human cases: occupational asbestos exposure (Table 2 as scanned lists 3, 13 and 10 years of exposure; chrysotile made up 65%, 55% and 70% of fibers). In vitro: UICC chrysotile A added to macrophage cultures at 75 micrograms per ml for 24 hours or 5 days. Controls: native Thetford mines (Canada) chrysotile and UICC chrysotile A.
• Main results:
  • Control fibers: treatment with formaldehyde and sodium hypochlorite did not change silicon and magnesium content. The treated-to-natural ratio ranged from 0.99 to 1.04 over 1 to 15 weeks.
  • Chrysotile fibers from the human lungs had larger Si:Mg ratios than control fibers.
  • In the human lung fibers, the Si:Mg ratio differed at points along the same fiber, which the authors took to mean magnesium loss was not uniform. For example, a fiber from case 2 measured 28.4, 34.5 and 28.3 at three points.
  • In some coated fibers from human lungs, magnesium could no longer be detected.
  • Fibers taken up by rabbit macrophages had Si:Mg ratios of 5.40 to 9.37 after 24 hours.
  • Fibers taken up by rabbit macrophages had Si:Mg ratios of 3.91 to 5.11 after 5 days.
  • Fibers kept without cells had lower ratios: 1.78 to 2.88 in Eagle BME culture medium and 1.49 to 2.51 in saline. The culture medium itself did not change the ratio.
  • Fibers outside the macrophages had values similar to control fibers incubated without macrophages.
  • Fibers taken up by macrophages in vitro also showed ratios that varied along the fiber, the same pattern seen in human lung fibers.
• The authors' conclusion: The authors suggested that biochemical factors from cell metabolism may attack fibers inside cells. They proposed this may account for the loss of magnesium relative to silicon in fibers residing in the body. They also proposed that uneven magnesium loss may give a fiber different reactivity at different points along its length, possibly due to macrophage metabolic products.
• Limitations the authors state:
  • Small variations in control-fiber ratios were attributed to electronic variation of the analytic instrument.
  • The steps used to prepare the macrophages for microscopy caused the cells to shrink (retract).

Topics

Medical terms in this study, explained in our Lexicon: Chrysotile, Alveolar Macrophage, Asbestos Exposure.

Related studies

• Effects of asbestos on the random migration of rabbit alveolar macrophages — Q.N. Myrvik, E.A. Knox, et al. (1985)
• 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)
• In vitro reactivity of alveolar macrophages and red blood cells with asbestos fibres treated with oxalic acid, sulfur dioxide and benzo-3,4-pyrene — M.C. Jaurand, L. Magne, et al. (1981)
• Phagocytosis of asbestos fibers by human pulmonary alveolar macrophages — T. McLemore, M. Corson, et al. (1979)
• Response of bovine alveolar macrophages in vitro to welding fume particles — L.R. White, A.B. Marthinsen, et al. (1983)
• Comparison of phagocytosis of uncoated versus coated asbestos fibers by cultured human pulmonary alveolar macrophages — T.L. McLemore, V. Roggli, et al. (1981)

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