Asbestos body phagocytosis by human free alveolar macrophages

Our plain-English summary of Asbestos body phagocytosis by human free alveolar macrophages, by T.L. McLemore, M.L. Mace, V. Roggli, et al (Cancer Letters, 1980).

The study

• Authors: T.L. McLemore, M.L. Mace, V. Roggli, M.V. Marshall, E.C. Lawrence, R.K. Wilson, R.R. Martin, B.R. Brinkley, S.D. Greenberg
• Journal: Cancer Letters
• Published: 1980;9(2):85-93
• Cited by: 23 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000840).

Abstract

Phagocytosis of asbestos bodies by human free alveolar macrophages (FAMs) was documented employing light microscopy. This process was more carefully studied utilizing scanning electron microscopy (SEM) which demonstrated morphological and surface membrane changes in FAMs following phagocytosis of asbestos bodies. FAM viability was also evaluated following 24--72-h incubation of cells with asbestos bodies at a final concentration of 250 micrograms/ml. Slight, but significant, cytotoxicity was observed following the initial 24-h culture period (P = 0.032, paired, 2-tailed t-test). No further cytotoxicity was observed, however, when cells were further incubated for 48-h and 72-h intervals (P greater than 0.05 in all instances). These studies demonstrate asbestos bodies are readily phagocytized by cultured FAMs, and are only slightly cytotoxic to these human lung cells.

In plain English

This laboratory study examined how human lung immune cells called free alveolar macrophages respond to asbestos bodies (asbestos fibers that have become coated inside the lung). The macrophages were collected by lung washing from 7 healthy non-smoking volunteers aged 21 to 24. The asbestos bodies were extracted from lung tissue taken at autopsy from 3 asbestos insulation workers aged 62 to 78. The article does not say which asbestos fiber type they contained. Cells were cultured with asbestos bodies at 250 micrograms per millilitre. Under light and scanning electron microscopes, the macrophages were seen engulfing asbestos bodies, with changes in cell shape and surface membranes. Cell survival was slightly lower than in control cultures after 24 hours (P = 0.032), but no further loss was seen at 48 and 72 hours (P greater than 0.05). The authors concluded that asbestos bodies are readily engulfed and only slightly toxic to these cells. They said the findings support the theory that coated asbestos fibers are less harmful to human lung cells than uncoated fibers.

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) cell-culture experiment using light microscopy, scanning electron microscopy and a cell-viability test
• Who was studied: Free alveolar macrophages (lung immune cells) collected by bronchoscopic saline lavage from 7 healthy, non-smoking volunteers aged 21 to 24 with no occupational exposure to asbestos or other particulates; Baylor College of Medicine, Houston, Texas
• Exposure: Asbestos bodies (coated asbestos fibers) recovered by bleach digestion of autopsy lung tissue from 3 asbestos insulation workers aged 62 to 78, added to cell cultures at 250 micrograms per millilitre for periods from 1 hour up to 72 hours. The fiber type is not stated.
• Main results:
  • Under the light microscope, macrophages incubated for 1 hour with asbestos bodies were seen engulfing (phagocytizing) an asbestos body.
  • Scanning electron microscopy showed stages of engulfment, including a macrophage that had completely engulfed a small asbestos body and was distorted in shape, and blebbing of the cell membranes.
  • Macrophages cultured with asbestos bodies had slightly lower viability than control cultures after 24 hours (P = 0.032, paired 2-tailed Student's t-test).
  • No further loss of viability was found at 48 and 72 hours of culture with asbestos bodies (P greater than 0.05 in all instances).
• The authors' conclusion: The authors concluded that asbestos bodies are readily phagocytized by cultured human macrophages and are only slightly cytotoxic to them. They said this supports the theory that asbestos bodies are less harmful to human lung cells than uncoated asbestos fibers, a comparison they drew with an earlier study from their laboratory that used raw fibers.

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos Body Formation, Phagocytosis, Alveolar Macrophage, Asbestos Bodies, Scanning Electron Microscopy (SEM).

Related studies

• Comparison of phagocytosis of uncoated versus coated asbestos fibers by cultured human pulmonary alveolar macrophages — T.L. McLemore, V. Roggli, et al. (1981)
• Phagocytosis of asbestos fibers by human pulmonary alveolar macrophages — T. McLemore, M. Corson, et al. (1979)
• Asbestos-stimulated tumour necrosis factor release from alveolar macrophages depends on fibre length and opsonization — K. Donaldson, X.Y. Li, et al. (1992)
• Phagocytosis of hemozoin (native and synthetic malaria pigment), and Plasmodium falciparum intraerythrocyte-stage parasites by human and mouse phagocytes — P. Olliaro, L. Lombardi, et al. (2000)
• Leaching of chrysotile asbestos in human lungs. Correlation with in vitro studies using rabbit alveolar macrophages — M.C. Jaurand, J. Bignon, et al. (1977)
• Degradation of cartilage proteoglycan and collagen by synovial cells. Stimulation by macrophages under activation by phagocytosis, lymphocyte factors, bacterial products or other inflammatory stimuli — C. Peeters-Joris, G. Vaes (1984)

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