Elemental and immunohistochemical analysis of the lungs and hilar lymph node in a patient with asbestos exposure, a pilot study

Our plain-English summary of Elemental and immunohistochemical analysis of the lungs and hilar lymph node in a patient with asbestos exposure, a pilot study, by Y. Koga, T. Satoh, K. Kaira, et al (Environmental Health and Preventive Medicine, 2016).

The study

• Authors: Y. Koga, T. Satoh, K. Kaira, M. Koka, T. Hisada, J. Hirato, B. Altan, M. Yatomi, A. Ono, Y. Kamide, Y. Shimizu, H. Aoki-Saito, H. Tsurumaki, K. Shimizu, A. Mogi, T. Ishizuka, M. Yamada, K. Dobashi
• Journal: Environmental Health and Preventive Medicine
• Published: 2016;21(6):492-500
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objectives: Studies have shown that inhaled mine dust, such as asbestos, can be translocated to various organs including the lymph nodes. Recently, we have established a protocol that enables us to identify inhaled elements using paraffin embedded lung specimens by in-air microparticle-induced X-ray emission (micro-PIXE). However, little research has examined the concentration of these inhaled fibers in various organs or the mechanisms of their translocation. In this study, we compared the concentration of inhaled fibers in the lung parenchyma to the concentration in the hilar lymph node as well as to determine the elemental spatial distribution of the inhaled fibers in a patient with occupational asbestos exposure.

Methods: Lung tissues and hilar lymph node in a patient with asbestos exposure were used in this study. Elemental analysis was performed by in-air micro-PIXE. Immunohistochemical analysis was performed using anti CD163, smooth muscle actin, vimentin and β-catenin antibody.

Results: The analysis revealed that the amount of inhaled silicon was approximately 6 times higher in the lymph node than in the lungs. The spatial analysis showed that silicon, iron and aluminium were co-localized in the hilar lymph node. The immunohistochemical analysis showed localized agreement of the inhaled fibers with macrophages, smooth muscle actin, and vimentin in the hilar lymph node.

Conclusions: This study showed that in-air micro-PIXE could be useful for analyzing the elemental distribution and quantification of inhaled fibers in the human body. Furthermore, immunohistochemistry in combination with in-air micro-PIXE analyses may help to determine the mechanism of mine dust distribution in vivo.

In plain English

This pilot study examined tissue from one 76-year-old man who had cut asbestos and worked in electrical insulation and welding. He had calcified pleural plaques, two separate primary lung cancers, and a 55 pack-year smoking history. The article did not identify the asbestos fiber type this patient was exposed to. The authors used in-air micro-PIXE to measure elements in stored tissue from both lungs and a right hilar lymph node. They also stained for macrophages (scavenger cells) and for markers of a cell change called EMT. The control was lung tissue from a woman with early-stage lung adenocarcinoma and no history of smoking or occupational dust exposure. Silicon was significantly higher in the lymph node than in either lung; the abstract calls it approximately 6 times higher. Magnesium and iron were significantly higher in the lymph node than in the left lung. Aluminium was 3 times higher, but the difference was not significant. Macrophages and the EMT markers were found around fibers in the lymph node. The authors concluded that in-air micro-PIXE could be useful for studying inhaled fibers in the body.

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: Pilot study of tissue from a single patient, combining elemental analysis by in-air micro-PIXE with immunohistochemistry. Lung tissue from one patient without occupational dust exposure served as a control.
• Who was studied: One 76-year-old man with occupational asbestos exposure, pleural thickening and double primary lung cancers: a large cell carcinoma in the right upper lobe and an adenosquamous carcinoma in the lower left lobe. He was a former smoker of 55 pack-years. The control was lung tissue from a 74-year-old woman, a housekeeper with no history of smoking or occupational dust exposure, who had surgery for early-stage (stage IA) adenocarcinoma.
• Exposure: Occupational asbestos exposure from cutting asbestos, with electrical insulation and welding work for 14 years. A figure caption instead says 15 years at a shipyard. The exposure occurred over 40 years before the investigation. The fiber type for this patient is not identified; the article names amosite and chrysotile only when discussing other studies.
• Main results:
  • Silicon (measured relative to sulphur) was significantly higher in the right hilar lymph node than in the right or left lung tissue. The abstract states it was approximately 6 times higher.
  • Magnesium and iron were significantly higher in the right hilar lymph node than in the left lung tissue.
  • Aluminium was 3 times higher in the lymph node than in either lung, but the difference was not significant.
  • Aluminium, iron, magnesium and silicon appeared in the same locations in the right hilar lymph node, but not in the lung tissue.
  • In the control lung, very low levels of iron and silicon were detected. Magnesium and aluminium were below the detection level.
  • Staining for macrophages (CD163) was strong in the lymph node and weak in the lung tissue. Macrophages gathered around the inhaled fibers.
  • Smooth muscle actin (SMA) was found with inhaled fibers in the lung tissue and the lymph node. Vimentin and beta-catenin were expressed around fibers in the lymph node.
  • Most fibers seen in the hilar lymph node under polarized light microscopy were less than 5 micrometres long.
  • The authors suggested the aluminium may have come from welding fumes, because asbestos does not contain aluminium.
• The authors' conclusion: The authors concluded that in-air micro-PIXE could be useful for analyzing the distribution and amount of inhaled fibers in the human body. They added that combining it with immunohistochemistry may help determine how mine dust spreads in the body.
• Limitations the authors state:
  • The authors stated that further studies are needed on the relationship between EMT processes and cancer after asbestos exposure.
  • The detection sensitivity for silicon and magnesium had not been determined; the authors assumed it was similar to that for aluminium or iron.
  • Light elements such as magnesium appeared spread across the tissue maps, which the authors attributed to background from the ion beam.
  • The equipment needs a powerful proton ion beam, which is very expensive.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Translocation, Parenchyma, Elemental Analysis, Macrophage, Immunohistochemistry.

Related studies

• Characteristics of asbestos concentration in lung as compared to asbestos concentration in various levels of lymph nodes that collect drainage from the lung — R.F. Dodson, S. Shepherd, et al. (2007)
• Asbestos fibers in para-aortic and mesenteric lymph nodes — T. Uibu, E. Vanhala, et al. (2009)
• Asbestos content of lung tissue, lymph nodes, and pleural plaques from former shipyard workers — R.F. Dodson, M.G. Williams, et al. (1990)
• Intrapulmonary lymph nodes. Clinical, radiologic, and pathologic features — R.L. Kradin, P.W. Spirn, et al. (1985)
• A comparison of asbestos burden in lung parenchyma, lymph nodes, and plaques — R.F. Dodson, M.G. Williams, et al. (1991)
• Pleural mesothelioma in a woman whose documented past exposure to asbestos was from smoking asbestos-containing filtered cigarettes: the comparative value of analytical transmission electron microscopic analysis of lung and lymph-node tissue — R.F. Dodson, S.P. Hammar (2006)

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