Biopersistence of cerium in the human respiratory tract and ultrastructural findings

Our plain-English summary of Biopersistence of cerium in the human respiratory tract and ultrastructural findings, by J.C. Pairon, F. Roos, P. Sébastien, et al (American Journal of Industrial Medicine, 1995).

The study

• Authors: J.C. Pairon, F. Roos, P. Sébastien, B. Chamak, I. Abd-Alsamad, J.F. Bernaudin, J. Bignon, P. Brochard
• Journal: American Journal of Industrial Medicine
• Published: 1995;27(3):349-58
• Type of article: Case report
• Cited by: 26 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

For diagnostic purposes, mineralogical analysis was performed in bronchoalveolar lavage fluid and lung tissue from a 58-year-old patient previously exposed to asbestos and rare earth dusts. No significant retention of asbestos was demonstrated in lung tissue by light microscopy (asbestos bodies) or transmission electron microscopy analysis (uncoated fibers). Particles containing rare earth (cerium, lanthanum) and phosphorus were identified in alveolar macrophages in bronchoalveolar lavage fluid, and cerium-containing particles accounted for 70% of particles observed in the lung tissue. Ultrastructural analysis of lung tissue revealed the presence of particles containing cerium and phosphorus in interstitial macrophages and elastic fibers. These results suggest that rare earth is metabolized and should be considered as biopersistent in the human respiratory tract, since occupational inquiries revealed that exposure to cerium oxide abrasive powder had ceased at least 15 years earlier.

In plain English

This case report described a 58-year-old man admitted to a chest unit in 1980 with recent breathlessness. He had worked as a plumber and roofer from 1935 to 1959 and had used cerium oxide powders to polish crystal glass from 1963 to 1967. The authors analyzed lung washings (bronchoalveolar lavage) from 1980 and 1988, lung biopsies from 1980 and 1988, and autopsy lung tissue from 1990. The 1980 washings contained 15 typical ferruginous bodies per ml, with chrysotile and amosite cores, but no uncoated asbestos fibers. Lung tissue from 1988 and 1990 showed no significant asbestos retention. In the samples analyzed for rare earth particles, cerium was always found together with phosphorus. In the 1988 biopsy, 71% of the nonfibrous mineral particles analyzed contained cerium. Such particles lay in interstitial macrophages and among elastic fibers. The authors judged an asbestos origin of the pleural thickening highly probable. They concluded that asbestos could be a major determinant of the lung lesions, but that long-term cerium retention suggested cerium may have contributed. They also concluded that inhaled cerium oxide can be metabolized in humans, forming insoluble cerium phosphate.

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: case report (one patient), with repeated mineralogical and electron-microscope analysis of lavage fluid and lung tissue
• Who was studied: One 58-year-old man, a smoker of 50 pack-years who had not smoked for 8 years, admitted in 1980 for recent onset of dyspnea. Samples were taken in 1980, 1988 and at autopsy in 1990.
• Exposure: Asbestos from work as a plumber and roofer (1935 to 1959). Cerium oxide abrasive powders used for polishing crystal glass (1963 to 1967). Possible rare earth exposure as a movie projectionist (1951 to 1964).
• Main results:
  • Occupational inquiries identified use of cerium oxide powders for polishing crystal glass from 1963 to 1967 as a source of cerium exposure.
  • 1980 lavage fluid: ferruginous bodies at 41/ml, of which 15/ml were typical and 26/ml atypical.
  • 1980 lavage fluid: the cores of the typical ferruginous bodies were chrysotile and amosite. No uncoated asbestos fibers were found.
  • 1980 lavage fluid: about 10% of alveolar macrophages contained dense particles containing phosphorus, calcium, lanthanum and cerium.
  • 1980 transbronchial biopsy: dense particles with rare earth phosphate chemistry were found in interstitial macrophages and intermingled with elastic fibers.
  • 1988 lavage fluid: results were similar to 1980, with 26 typical and 60 atypical ferruginous bodies.
  • 1988 lung biopsy: 875 asbestos bodies per gram of dry lung tissue.
  • 1988 lung biopsy: one sample was analyzed for nonfibrous mineral particles. Of these nonfibrous particles, 71% contained cerium, although the total particle concentration was within the range seen in the general population in the authors' laboratory.
  • 1988 lung biopsy: the concentration of cerium-containing particles was well above the highest value seen in the laboratory's controls.
  • 1990 autopsy lung tissue: both the asbestos body count and the uncoated fiber count were below the laboratory's thresholds for significant asbestos retention. The asbestos body threshold was 1,000 per gram of dry lung tissue.
  • In the samples analyzed for rare earth particles, cerium was always found together with phosphorus. The autopsy samples were analyzed only for asbestos bodies and uncoated fibers. The patient's polishing powders contained cerium, with or without lanthanum, but no phosphorus.
  • Because exposure to rare earths ended in 1967, the authors stated that these compounds can persist in the respiratory system for at least 21 years.
  • The authors judged an asbestos origin of the pleural thickening highly probable. They found the origin of the parenchymal lung disease harder to attribute exclusively to asbestos.
• The authors' conclusion: The authors concluded that asbestos could be a major determinant of the respiratory lesions in this case. They also concluded that long-term retention of cerium and its distribution in lung tissue suggested a possible contribution of cerium. In their view, inhaled cerium oxide-containing particles can be metabolized in humans to insoluble cerium phosphate. They called for prospective studies of rare earth-exposed workers.

Topics

Medical terms in this study, explained in our Lexicon: biopersistence, Bronchoalveolar Lavage (BAL), Asbestos Bodies, Transmission Electron Microscopy (TEM), Alveolar Macrophage, Interstitial, Macrophage.

Related studies

• Electron microscopic findings in the lungs of miners — G. Harrison, N.L. Lapp (1972)
• Characterization of the lower respiratory tract inflammation of nonsmoking individuals with interstitial lung disease associated with chronic inhalation of inorganic dusts — W.N. Rom, P.B. Bitterman, et al. (1987)
• Lung cell toxicity experimentally induced by a mixed dust from Mexicali, Baja California, Mexico — A.R. Osornio-Vargas, N.A. Hernández-Rodríguez, et al. (1991)
• Serum protein concentrations and respiratory tract abnormalities following short-term exposure to amosite: a comparison between former asbestos workers and unexposed controls — D.R. Nash, N.G. Fortson, et al. (1981)
• A biopersistence study following exposure to chrysotile asbestos alone or in combination with fine particles — D.M. Bernstein, K. Donaldson, et al. (2008)
• Guidelines for mineral fibre analyses in biological samples: report of the ERS Working Group. European Respiratory Society — P. De Vuyst, A. Karjalainen, et al. (1998)

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