Immunomodulatory effects in workers exposed to naturally occurring asbestos fibers

Our plain-English summary of Immunomodulatory effects in workers exposed to naturally occurring asbestos fibers, by C. Ledda, C. Costa, S. Matera, et al (Molecular Medicine Reports, 2017).

The study

• Authors: C. Ledda, C. Costa, S. Matera, B. Puglisi, V. Costanzo, M. Bracci, C. Fenga, V. Rapisarda, C. Loreto
• Journal: Molecular Medicine Reports
• Published: 2017;15(5):3372-3378
• Cited by: 18 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Natural asbestiform fibers are defined 'naturally occurring asbestos' (NOA) and refer to the mineral as a natural component of soils or rocks. The release of NOA fibers into the air from rocks or soils by routine human activities or natural weathering processes represents a risk for human beings. Fluoro-edenite (FE) is a NOA fiber detected in the benmoreitic lava in the area of Biancavilla, South-west slope of Mt. Etna. The aim of the present study was to investigate FE immunotoxicity pathways in a group of 38 occupationally exposed construction workers, in order to find any biological markers of its effect. Subjects underwent respiratory function tests and HRCT total chest scanning. Serum IL-1β, IL-6, IL-8 and TNF-α were measured. The presence of PPs was significantly greater in subjects exposed than in the control (25 vs. 2). In subjects exposed to FE, IL-1β and TNF-α values were significantly higher than the controls. The previously observed increase of IL-1β and IL-18 showed a probable involvement of the proteic complex defined inflammosome by FE fibers.

In plain English

This study compared 38 male construction workers who lived and worked in Biancavilla, Sicily, Italy, with 38 male construction workers who lived and worked at least 40 km away. Local lava rock in Biancavilla contains fluoro-edenite, a naturally occurring asbestiform fiber. Of the exposed workers, 21 (55%) had handled gravel from the local Mount Calvario quarry until 1998. All workers had breathing tests, high-resolution CT chest scans and blood tests for four inflammation markers (cytokines). The two groups were similar in age, body mass index (BMI), smoking, drinking and years worked. Pleural plaques were found in 25 (66%) exposed workers and 2 (5%) controls. Average blood levels of IL-1β and TNF-α were significantly higher in exposed workers. IL-6 and IL-8 were higher, but not statistically significantly. Two exposed workers had a restrictive breathing defect and one had an obstructive defect. The authors concluded that fluoro-edenite may conceivably trigger inflammatory processes that, as with asbestos, may activate the inflammasome, a protein complex involved in inflammation.

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: Comparison study of fiber-exposed construction workers and an unexposed control group of construction workers, using questionnaire, spirometry, HRCT chest scans and blood tests
• Who was studied: 38 construction workers residing and working in Biancavilla (Sicily, Italy) and 38 control construction workers living and working at least 40 km away; all were male. Study dates are not given.
• Exposure: Fluoro-edenite (FE), a naturally occurring asbestiform fiber in local lava used as building material. 21 (55%) exposed workers had handled gravel from the Mount Calvario quarry until 1998, and all had restored houses built with quarry lava. No fiber measurements were reported.
• Main results:
  • Pleural plaques were present in 25 (66%) exposed workers and 2 (5%) controls (P<0.0001 in Table I).
  • Among the 25 exposed workers with pleural involvement, 21 (84%) had bilateral plaques. Calcifications were reported in 5 (17%) participants.
  • HRCT showed low-grade fibrosis in 3 exposed workers (one unilateral, two bilateral). Table I reports parenchymal abnormalities in 3 (8%) exposed workers versus 0 (0%) controls.
  • Mean serum IL-1β was 27.51 plus or minus 8.43 pg/ml in exposed workers versus 15.28 plus or minus 5.64 pg/ml in controls (P<0.0001).
  • Mean serum TNF-α was 21.14 plus or minus 6.13 pg/ml in exposed workers versus 9.79 plus or minus 3.81 pg/ml in controls (P<0.0001).
  • IL-6 and IL-8 were higher in exposed workers than in controls, but not statistically significantly (P greater than 0.05).
  • In the exposed group, two workers (5%) had a restrictive and one (3%) an obstructive ventilatory defect. All controls were in the normal range.
  • Age, body mass index, smoking, alcohol consumption and working age did not differ between exposed workers and controls.
• The authors' conclusion: The authors considered it conceivable that fluoro-edenite triggers inflammatory processes that, as with asbestos, may lead to activation of the inflammasome. They said research on immune-modulators in fluoro-edenite-related disease should continue.

Topics

Medical terms in this study, explained in our Lexicon: naturally occurring asbestos (NOA), Asbestiform, fluoro-edenite, Biancavilla, High-Resolution CT (HRCT).

Related studies

• Mesothelin methylation, soluble mesothelin related protein levels and inflammation profiling in workers chronically exposed to naturally occurring asbestos fibers — C. Ledda, C. Loreto, et al. (2024)
• FBLN-3 as a biomarker of pleural plaques in workers occupationally exposed to carcinogenic fibers: a pilot study — V. Rapisarda, C. Ledda, et al. (2015)
• Evaluation of public and worker exposure due to naturally occurring asbestos in gravel discovered during a road construction project — R.A. Perkins, J. Hargesheimer, et al. (2008)
• Analysis of fibulin-3 after exposure to asbestos-like fibers — V. Rapisarda, R. Caltabiano, et al. (2017)
• Prevalence of anti-nuclear autoantibodies in subjects exposed to natural asbestiform fibers: a cross-sectional study — C. Ledda, R. Caltabiano, et al. (2018)
• 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)

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