Asbestos fibers in para-aortic and mesenteric lymph nodes

Our plain-English summary of Asbestos fibers in para-aortic and mesenteric lymph nodes, by T. Uibu, E. Vanhala, A. Sajantila, et al (American Journal of Industrial Medicine, 2009).

The study

• Authors: T. Uibu, E. Vanhala, A. Sajantila, P. Lunetta, P. Mäkelä-Bengs, S. Goebeler, M. Jäntti, A. Tossavainen
• Journal: American Journal of Industrial Medicine
• Published: 2009;52(6):464-70
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Asbestos fibers are known to accumulate in lung parenchyma and thoracic lymph nodes, but their presence and translocation into the extrapulmonary tissues need clarification. We assessed the presence of asbestos in the para-aortic (PA) and mesenteric (ME) lymph nodes.

Methods: PA and ME lymph nodes and lung tissue from 17 persons who underwent medicolegal autopsy for suspicion of asbestos-related disease and from five controls were analyzed for asbestos fibers using transmission electron microscopy.

Results: High concentrations of amphibole asbestos fibers were detected in several lung tissue samples and in the respective PA and ME lymph nodes. The mean concentration for the 10 persons with a lung asbestos content of >/=1 million fibers/g of dry tissue (f/g) was 0.85 (<0.05-4.36) million f/g in the PA lymph nodes and 0.55 (<0.02-2.86) million f/g in the ME lymph nodes. The respective mean values for the 12 persons with a lung asbestos concentration of <1 million f/g were 0.07 for the PA lymph nodes and 0.03 million f/g for the ME nodes. The lung asbestos burden that predicted the detection of asbestos in abdominal lymph nodes was 0.45 million f/g.

Conclusions: In addition to their accumulation in lung tissue, asbestos fibers also collect in the retroperitoneal and the mesenteric lymph nodes. Even low-level occupational exposure results in the presence of crocidolite, amosite, anthophyllite, tremolite, or chrysotile in these abdominal lymph nodes. Our results support the hypothesis of lymph drainage as an important translocation mechanism for asbestos in the human body.

In plain English

This Finnish autopsy study looked for asbestos fibers in two groups of abdominal lymph nodes: para-aortic nodes, near the aorta at the level of the kidney arteries, and mesenteric nodes, beside the small intestine. The authors used transmission electron microscopy to examine these nodes and lung tissue from 22 men aged 52 to 85 who had medicolegal autopsies in Helsinki and Tampere between 2002 and 2006. Seventeen were suspected of an asbestos-related death. Five were controls whose work histories made occupational exposure unlikely. Among the 10 men with at least 1 million fibers per gram of dry lung tissue, fibers were found in the para-aortic nodes of 8 and the mesenteric nodes of 8, with mean levels of 0.85 and 0.55 million fibers per gram. Among the 12 men with lower lung levels, 5 had fibers in at least one node group. Lung levels were higher than node levels. Nearly all fibers were amphiboles, and chrysotile was found in two persons. The authors concluded that their results support the hypothesis that lymph drainage is an important route by which asbestos moves through 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: Autopsy tissue study: lymph nodes and lung tissue from suspected asbestos-related deaths and from controls, analyzed by transmission electron microscopy
• Who was studied: 22 men aged 52 to 85 at death who underwent medicolegal autopsy at the Departments of Forensic Medicine in Helsinki and Tampere, Finland, from September 2002 to November 2006. Seventeen were cases with suspected asbestos-related death and 5 were male controls autopsied for other reasons. Persons with visible tumor spread in the para-aortic or mesenteric regions were excluded.
• Exposure: Cases had suspected asbestos-related causes of death and worked in jobs such as insulator, construction worker, shipyard worker and brick mason. Controls had work histories with unlikely occupational asbestos exposure. Fibers identified were anthophyllite, amosite, crocidolite, tremolite and, in two persons, chrysotile.
• Main results:
  • Among the 10 men with a lung level of at least 1 million fibers per gram of dry tissue, asbestos fibers were detected in the para-aortic nodes of 8 of 10 (80%) and the mesenteric nodes of 8 of 10 (80%). All 10 had fibers in at least one of the two node groups.
  • In those 10 men, the mean concentration was 0.85 (range under 0.05 to 4.36) million fibers per gram in the para-aortic nodes and 0.55 (range under 0.02 to 2.86) million fibers per gram in the mesenteric nodes.
  • Among the 12 men with a lung level below 1 million fibers per gram, fibers were found in 4 of 12 (33%) para-aortic and 3 of 12 (25%) mesenteric node samples. Five of 12 (42%) had fibers in either node group. Mean levels were 0.07 (para-aortic) and 0.03 (mesenteric) million fibers per gram.
  • Compared with the higher-lung-level group, the lower frequency of positive results in this group was statistically significant for the mesenteric nodes and for all abdominal nodes combined, but not for the para-aortic nodes.
  • Fiber content was clearly higher in lung tissue than in the lymph nodes. The differences between para-aortic and mesenteric nodes were not significant.
  • In samples where fibers were found, concentrations were 72 (range 0.5 to 644) times lower in para-aortic nodes and 60 (range 2 to 260) times lower in mesenteric nodes than in lung tissue. No correlation was found between lung levels and abdominal node levels.
  • A lung level of 0.45 million fibers per gram predicted the detection of asbestos in the abdominal lymph nodes. The area under the curve for this analysis was 0.900.
  • Virtually all fibers detected were amphiboles, and chrysotile was found in two persons. The fiber types in the lymph nodes were the same as those in the matching lung samples.
• The authors' conclusion: The authors concluded that asbestos fibers can be found in the retroperitoneal and mesenteric lymph nodes even in most people with low-level occupational exposure. They also concluded that their results support the hypothesis that lymph drainage is an important way asbestos moves through the body.
• Limitations the authors state:
  • The sample preparation method did not allow reliable counting of asbestos bodies.
  • One control had a high lung asbestos level. The authors said this illustrates the difficulty of recognizing exposure in atypical work situations.
  • The authors stated that their results do not rule out that fibers in the mesenteric nodes were swallowed and passed through the gut.

Topics

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

Medical terms in this study, explained in our Lexicon: Parenchyma, Translocation, Autopsy, Transmission Electron Microscopy (TEM), Amphibole Asbestos, Occupational Exposure, Crocidolite, Amosite.

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 content of lung tissue, lymph nodes, and pleural plaques from former shipyard workers — R.F. Dodson, M.G. Williams, et al. (1990)
• 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)
• Elemental and immunohistochemical analysis of the lungs and hilar lymph node in a patient with asbestos exposure, a pilot study — Y. Koga, T. Satoh, et al. (2016)
• Asbestos content in the lymph nodes of nonoccupationally exposed individuals — R.F. Dodson, J. Huang, et al. (2000)

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