Laser ablation inductively coupled plasma mass spectrometry as a novel clinical imaging tool to detect asbestos fibres in malignant mesothelioma

Our plain-English summary of Laser ablation inductively coupled plasma mass spectrometry as a novel clinical imaging tool to detect asbestos fibres in malignant mesothelioma, by O.M. Voloaca, C.J. Greenhalgh, L.M. Cole, et al (Rapid Communications in Mass Spectrometry, 2020).

The study

• Authors: O.M. Voloaca, C.J. Greenhalgh, L.M. Cole, M.R. Clench, A.J. Managh, S.L. Haywood-Small
• Journal: Rapid Communications in Mass Spectrometry
• Published: 2020;34(21):e8906
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Rationale: Malignant pleural mesothelioma is an extremely aggressive and incurable malignancy associated with prior exposure to asbestos fibres. Difficulties remain in relation to early diagnosis, notably due to impeded identification of asbestos in lung tissue. This study describes a novel laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) imaging approach to identify asbestos within mesothelioma models with clinical significance.

Methods: Human mesothelioma cells were exposed to different types of asbestos fibres and prepared on plastic slides for LA-ICP-MS analysis. No further sample preparation was required prior to analysis, which was performed using an NWR Image 266 nm laser ablation system coupled to an Element XR sector-field ICP mass spectrometer, with a lateral resolution of 2 μm. Data was processed using LA-ICP-MS ImageTool v1.7 with the final graphic production made using DPlot software.

Results: Four different mineral fibres were successfully identified within the mesothelioma samples based on some of the most abundant elements that make up these fibres (Si, Mg and Fe). Using LA-ICP-MS as an imaging tool provided information on the spatial distribution of the fibres at cellular level, which is essential in asbestos detection within tissue samples. Based on the metal counts generated by the different types of asbestos, different fibres can be identified based on shape, size, and elemental composition. Detection of Ca was attempted but requires further optimisation.

Conclusions: Detection of asbestos fibres in lung tissues is very useful, if not necessary, to complete the pathological dt9iagnosis of asbestos-related malignancies in the medicolegal field. For the first time, this study demonstrates the successful application of LA-ICP-MS imaging to identify asbestos fibres and other mineral fibres within mesothelioma samples. Ultimately, high-resolution, fast-speed LA-ICP-MS analysis has the potential to be integrated into clinical workflow to aid earlier detection and stratification of mesothelioma patient samples.

© 2020 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd.

In plain English

This laboratory proof-of-concept study tested whether a technique called laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), which maps elements across a sample, could locate mineral fibres among mesothelioma cells. No patients or patient tissue were studied. The authors exposed a human mesothelioma cell line, NCI-H28, to 3 micrograms per millilitre of one fibre type: amosite, chrysotile or crocidolite asbestos, or wollastonite, a non-asbestiform fibre used as a control. Cells were spun onto plastic slides and scanned with a 2 micrometre laser spot. Iron, magnesium and silicon were each imaged separately. All four fibres were mapped. Iron signals were low for chrysotile, high for amosite and highest for crocidolite. Wollastonite showed no magnesium and a high silicon signal. Fibres hidden inside or beneath cells under the microscope still appeared in the element maps. Calcium could not be measured. The areas analysed were chosen because fibres were visible by microscope, and telling fibres apart blind was not yet done. The authors concluded the method could ultimately aid early diagnosis of pleural mesothelioma, but said testing in human lung tissue is still needed.

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 proof-of-concept experiment on a cultured human cell line (not a study of patients)
• Who was studied: Human mesothelioma cells of the NCI-H28 line (a model of epithelioid malignant pleural mesothelioma), obtained from the American Type Culture Collection. A biphasic cell line, MSTO-211H, was also used as a background, but its data were not presented.
• Exposure: UICC standard research-grade fibres: amosite, chrysotile and crocidolite asbestos, plus the non-asbestiform fibre wollastonite as a negative control. Cells were treated with 3 micrograms per millilitre of a single fibre type for 24 hours.
• Main results:
  • The fibres were identified by their iron, magnesium and silicon content. The authors mapped all four fibre types within the 2D cell preparations.
  • Chrysotile gave a low iron signal, which the authors linked to its limited iron content.
  • Amosite gave a high iron signal, in line with iron making up more than 39% of its nominal composition.
  • Crocidolite gave the highest iron signal of the fibres, matching its nominal composition.
  • Wollastonite showed no magnesium and a high silicon signal. A slight iron signal was seen, which the authors said could be explained by metal impurities.
  • Fibres that disappeared within or underneath cells in microscope images could still be seen in the LA-ICP-MS images.
  • Detection of calcium was attempted but was unsuccessful.
• The authors' conclusion: The authors concluded that these preliminary data suggest the instrument could ultimately be used in a clinical setting to aid early diagnosis of malignant pleural mesothelioma.
• Limitations the authors state:
  • The approach has not yet been validated in human lung tissue samples.
  • Only regions where fibres were already visible by optical microscopy were selected for analysis.
  • The elements were imaged separately rather than all at once, because of instrument speed.
  • Telling the fibre types apart in blind analysis, based on elemental composition alone, was described as a future step rather than something achieved.

Topics

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

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Pleural Mesothelioma, Mesothelioma.

Related studies

• Quantitative analysis of asbestos in drinking water and its migration in mice using fourier-transform infrared spectroscopy and inductively coupled plasma optical emission spectrometry — B. Zheng, L. Zang, et al. (2019)
• Detection of malignant pleural mesothelioma in exhaled breath by multicapillary column/ion mobility spectrometry (MCC/IMS) — K. Lamote, M. Vynck, et al. (2016)
• Applying Probe Electrospray Ionization Mass Spectrometry to Cytological Diagnosis: A Preliminary Study by Using Cultured Lung Cancer Cells — Y. Morimoto, T. Oya, et al. (2021)
• Evaluation of asbestos dispersion during laser ablation of rocks containing Naturally Occurring Asbestos (NOA) — A. Bloise, F. Parisi, et al. (2024)
• Elemental Mapping of Human Malignant Mesothelioma Tissue Samples Using High-Speed LA-ICP-TOFMS Imaging — O.M. Voloaca, M.R. Clench, et al. (2022)
• Sample preparation method for visualization of nanoparticulate captured on mixed cellulose ester filter media by enhanced darkfield microscopy and hyperspectral imaging — N.M. Neu-Baker, A.C. Eastlake, et al. (2019)

Browse return to medical research.