Asbestos fibre burden in gallbladder: A case study

Our plain-English summary of Asbestos fibre burden in gallbladder: A case study, by A. Croce, S. Capella, E. Belluso, et al (Micron, 2018).

The study

• Authors: A. Croce, S. Capella, E. Belluso, F. Grosso, N. Mariani, R. Libener, C. Rinaudo
• Journal: Micron
• Published: 2018;105:98-104
• Type of article: Case report
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The methods conventionally used to determine the burden of asbestos fibres inhaled/incorporated in lung require chemical digestion of the biological matrix before counting/characterising the inorganic fibrous phases under scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS). Asbestos fibres can also be present in extra-pulmonary organs, and we set out to quantify the fibres in gallbladder. Although the standardised procedure requires approximately 5 × 10-1 g of wet tissue, this amount of tissue is not always available. We applied the procedure on about 9 × 10-4 g of gallbladder from a patient with known environmental and workplace exposure to asbestos. The patient died of malignant pleural mesothelioma and was also affected by severe bile-tract problems. The traditional procedure of digesting tissue samples in NaClO and filtering the resulting suspension was carried out. The filter was then examined under SEM/EDS using two methods 1. following the standardised procedure to assess the fibre burden in lung by investigating only 2 mm2 of the filter (660 microscopic fields), and 2. analysing all the microscopic fields in one-quarter of the filter (about 82 mm2). In parallel, histological sections (prepared in the usual way for medical diagnosis) were analysed without digestion or manipulation of the sample using variable pressure SEM/EDS. The fibre counts obtained using the two methods were of the same order of magnitude, i.e., ∼105 fibres/g of wet tissue. We showed that the counting of fibres in human tissue may be successfully carried out even when a limited amount of tissue is available. We also found that, when exposure to asbestos is considerable, the number of asbestos fibres accumulating in the gallbladder may be significant.

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In plain English

This case study measured asbestos fibres in gallbladder tissue from one patient. She was an 80-year-old woman who died of malignant pleural mesothelioma; environmental and workplace asbestos exposure had been ascertained. Because the tissue available was limited, about 9 × 10^-4 g of tissue, weighed after paraffin removal, was digested for counting. The standard procedure used for lung samples analyses about 5 × 10^-1 g of wet tissue. The tissue was chemically digested and the resulting filter was examined by electron microscopy in two laboratories. One laboratory examined about 82 mm2 of filter and counted 62 fibres, or 2.9 × 10^5 fibres per gram of wet tissue. The other examined 2 mm2 and counted 3 fibres, or 3.3 × 10^5 per gram. The first method took 20 hours and the second 2 to 3 hours. On the filter, chrysotile was most frequent, and crocidolite and tremolite/actinolite were less frequent. Undigested tissue sections also showed chrysotile and crocidolite. The authors concluded that fibres can be counted in small tissue samples. They called the work preliminary and noted that three fibres give limited information about fibre characteristics.

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 study of one patient: laboratory analysis of gallbladder tissue by scanning electron microscopy with energy dispersive spectroscopy, on undigested histological sections and on chemically digested tissue. The digestion procedure is the one conventionally used for lung, which requires about 5 × 10^-1 g of wet tissue.
• Who was studied: Paraffin-embedded gallbladder tissue from one 80-year-old woman who died of malignant pleural mesothelioma (MPM) and also had severe bile-tract problems. The analyses were done in Alessandria and Turin, Italy. About 9 × 10^-4 g of tissue, weighed after paraffin removal, was digested, and further sections were examined without digestion.
• Exposure: Environmental and workplace exposure to asbestos was ascertained for the patient; the article does not give details of jobs or doses. The authors state that the minerals found corresponded to those most used in industries in Piedmont, where the patient worked, and in house roofs.
• Main results:
  • In undigested gallbladder sections, agglomerates of very thin fibrils were identified as chrysotile.
  • In undigested sections, some fibrous phases were identified as crocidolite. For some elongated serpentine crystals, the authors could not determine whether they were chrysotile (asbestos) or antigorite (not asbestos).
  • In the digested sample, fibre composition was most often chrysotile, and less often crocidolite or tremolite/actinolite asbestos.
  • University of Eastern Piedmont method: 82 mm2 of filter analysed, 62 serpentine and amphibole fibres counted, 2.9 × 10^5 fibres per gram of wet tissue.
  • University of Turin method: 2 mm2 of filter analysed, 3 serpentine and amphibole fibres counted, 3.3 × 10^5 fibres per gram of wet tissue.
  • The two methods gave fibre concentrations of the same order of magnitude, about 10^5 fibres per gram of wet tissue.
  • Characterising all fibres in a quarter of the filter (about 82 mm2) took 20 hours; analysing 2 mm2 took 2 to 3 hours.
• The authors' conclusion: The authors concluded that fibres in human tissues, not only from the respiratory system, can be counted even when only a limited amount of tissue is available.
• Limitations the authors state:
  • The amount of tissue available for analysis was limited, so the traditional procedure was applied to only about 9 × 10^-4 g of tissue.
  • The authors describe the work as a preliminary study and say additional cases are needed for statistically sounder results.
  • The 2 mm2 method detected only three fibres, which the authors say does not give deep knowledge of the fibres' characteristics.
  • The authors note difficulty in matching the chemical spectra to specific minerals. The chemical data are qualitative, and residual sodium hypochlorite from digestion appears in the spectra.
  • Tremolite and actinolite could not be definitely told apart.
  • Digestion and filtration likely broke apart fibre aggregates, so aggregates were rarely seen after digestion.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile, Crocidolite, Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Scanning Electron Microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Pleural Mesothelioma.

Related studies

• Asbestos fibres detected by scanning electron microscopy in the gallbladder of patients with malignant pleural mesothelioma (MPM) — F. Grosso, A. Croce, et al. (2017)
• Asbestos fibers in the gallbladder of patients affected by benign biliary tract diseases — F. Grosso, L. Randi, et al. (2015)
• Asbestos lung burden and asbestosis after occupational and environmental exposure in an asbestos cement manufacturing area: a necropsy study — C. Magnani, F. Mollo, et al. (1998)
• Stability of mineral fibres in contact with human cell cultures. An in situ μXANES, μXRD and XRF iron mapping study — S. Pollastri, A.F. Gualtieri, et al. (2016)
• The asbestos fibre burden in human lungs: new insights into the chrysotile debate — I.S. Feder, I. Tischoff, et al. (2017)
• Increased expression of epidermal growth factor receptor in rat pleural mesothelial cells correlates with carcinogenicity of mineral fibres — S.P. Faux, C.E. Houghton, et al. (2000)

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