Angiogenesis correlates with macrophage and mast cell infiltration in lung tissue of animals exposed to fluoro-edenite fibers

Our plain-English summary of Angiogenesis correlates with macrophage and mast cell infiltration in lung tissue of animals exposed to fluoro-edenite fibers, by G. Musumeci, C. Loreto, S. Giunta, et al (Experimental Cell Research, 2016).

The study

• Authors: G. Musumeci, C. Loreto, S. Giunta, V. Rapisarda, M.A. Szychlinska, R. Imbesi, A. Castorina, T. Annese, S. Castorina, P. Castrogiovanni, D. Ribatti
• Journal: Experimental Cell Research
• Published: 2016;346(1):91-8
• Cited by: 15 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Angiogenesis plays a crucial role in progression of pleural malignant mesothelioma. A significantly increased incidence of pleural mesothelioma has been attributed to exposure to fluoro-edenite, a fibrous amphibole extracted from a local stone quarry. In this study, we have investigated the expression of CD68-positive macrophages, tryptase-positive mast cells and CD31 positive areas, as expression of microvascular density, in lung tissue of sheeps exposed to fluoro-edenite fibers vs controls, by immunohistochemical, morphometric and Western blot analysis. The result have evidenced a significant increase in the expression of CD68-positive macrophages, tryptase-positive mast cells as well as a significant increase in microvascular density evaluated as CD31 positive areas in lung tissue of of sheeps exposed to fluoro-edenite fibers vs controls. These data confirmed the important role played by tumor microenvironment components, including macrophages and mast cells, in favour of angiogenesis in pleural mesothelioma induced by fluoro-edenite exposure.

Copyright © 2016 Elsevier Inc. All rights reserved.

In plain English

This was an animal study of sheep in Sicily, Italy. The authors examined lung tissue from 60 sheep that grazed 3 km from the town of Biancavilla, where fluoro-edenite, a fibrous amphibole, was extracted from a local stone quarry. They compared it with lung tissue from 10 control sheep that grazed about 50 km from the quarry. The animals were 4.0 to 6.5 years old and were slaughtered at a slaughterhouse. Using tissue staining, image analysis and Western blot, the authors measured markers of macrophages (CD68), mast cells (tryptase) and small blood vessels (CD31, used as a measure of microvascular density). Fluoro-edenite fibers were seen in the lungs of the exposed sheep. All three markers were higher in exposed sheep than in controls, and the authors reported these differences as statistically significant (p less than 0.05 or less than 0.01). The authors concluded that macrophages and mast cells play a role in favouring angiogenesis (new blood vessel growth) in pleural mesothelioma induced by fluoro-edenite exposure. The article does not report that any of these sheep had mesothelioma, and the authors state no limitations.

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: Animal study comparing lung tissue of environmentally exposed sheep with unexposed control sheep, using immunohistochemistry, morphometric (image) analysis and Western blot
• Who was studied: 60 sheep of both sexes randomly selected from six flocks grazing 3 km from Biancavilla (Sicily, Italy), and 10 control sheep from a flock grazing about 50 km from the Biancavilla stone quarry; ages 4.0 to 6.5 years; slaughtered at a slaughterhouse. Dates of sampling not stated.
• Exposure: Environmental exposure to fluoro-edenite, a fibrous amphibole extracted from a local stone quarry near Biancavilla, through grazing near the town. No fiber doses or air concentrations were measured.
• Main results:
  • Fluoro-edenite fibers were found in the lung tissue of exposed sheep, in close contact with the alveolar lining, bronchioles and interstitium.
  • CD68 (macrophage marker) staining differed between exposed and unexposed sheep, at both high and low staining intensity, with p less than 0.01.
  • Tryptase (mast cell marker) staining differed between exposed and unexposed lung tissue. The difference was p less than 0.05 for high-intensity staining and p less than 0.01 for low-intensity staining.
  • CD31 (blood vessel marker) staining differed between exposed and unexposed lung tissue at both high and low intensity, with p less than 0.01.
  • The percentage of lung area stained for CD68, tryptase and CD31 was higher in exposed sheep than in unexposed sheep (p less than 0.01, p less than 0.05 and p less than 0.01, respectively).
  • Western blot showed increased CD68 (p less than 0.05), tryptase (p less than 0.05) and CD31 (p less than 0.01) in lung tissue of exposed sheep.
• The authors' conclusion: The authors concluded that their data confirmed a role for tumor microenvironment components, including macrophages and mast cells, in favouring angiogenesis in pleural mesothelioma induced by fluoro-edenite exposure.

Topics

Medical terms in this study, explained in our Lexicon: Angiogenesis, Macrophage, fluoro-edenite, Malignant Mesothelioma, Pleural Mesothelioma, Amphibole Group, Tumor Microenvironment.

Related studies

• Asbestos-induced fibrosis in rats: increase in lung mast cells and autacoid contents — I. Keith, R. Day, et al. (1987)
• Immunohistochemical expression of retinoblastoma and phospho-retinoblastoma protein in sheep lung exposed to fluoro-edenite fibers — G. Musumeci, C. Loreto, et al. (2010)
• Defense and protection mechanisms in lung exposed to asbestiform fiber: the role of macrophage migration inhibitory factor and heme oxygenase-1 — C. Loreto, R. Caltabiano, et al. (2020)
• Monitoring of fluoro-edenite fibre pollution through the study of sheep lymph nodes as a model of a biological indicator — V. Rapisarda, G. Rapisarda, et al. (2005)
• Occupational exposure to fluoro-edenite and prevalence of anti-nuclear autoantibodies — V. Rapisarda, C. Loreto, et al. (2018)
• Mineral fibre toxicity: expression of retinoblastoma (Rb) and phospho-retinoblastoma (pRb) protein in alveolar epithelial and mesothelial cell lines exposed to fluoro-edenite fibres — G. Musumeci, V. Cardile, et al. (2011)

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