Recent advances in the early diagnosis of asbestosis

Our plain-English summary of Recent advances in the early diagnosis of asbestosis, by R. Bégin, G. Ostiguy, R. Filion, et al (Seminars in Roentgenology, 1992).

The study

• Authors: R. Bégin, G. Ostiguy, R. Filion, S. Groleau
• Journal: Seminars in Roentgenology
• Published: 1992;27(2):121-39
• Type of article: Review
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 004964).

Summary of the article

This review covered recent progress in three areas: understanding early lung injury after asbestos dust inhalation, recognizing these early events in humans, and recognizing early asbestosis clinically. The authors drew on rat studies by Brody and colleagues, their own sheep model, and studies of asbestos workers, including long-term miners and millers in Quebec's Eastern Townships. The described mechanisms began with fibers deposited at alveolar duct bifurcations and damaging epithelial cells. Macrophages then accumulated, and long fibers were incompletely phagocytosed. Activated macrophages released fibronectin, PDGF, IGF-1, oxygen radicals and plasminogen activator, which recruited fibroblasts and led to collagen deposition. Among workers without radiographic asbestosis, 50% showed enhanced gallium-67 lung uptake. In follow-up, 12 of 16 workers with normal radiographs and positive gallium scans (75%) progressed to clinical asbestosis. Lung lavage showed a subclinical alveolitis and gave information on fibrosing activity. The pulmonary pressure-volume curve could detect changes before the chest radiograph. The authors cited a study in which HRCT was abnormal in 57 of 169 exposed workers with normal radiographs. They listed five proposed HRCT criteria suggestive of asbestosis and noted that interpretation is controversial. In their experience, 10% to 20% of long-term exposed workers had HRCT findings suggestive of early asbestosis with a normal chest radiograph. They concluded that the diffuse character of such abnormalities would support interpreting them as early asbestosis.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This article is a review. The authors reviewed research, much of it their own, on how asbestosis begins and newer tests to detect it early. They described their sheep experiments, in which a single exposure to chrysotile asbestos fibers, unlike latex beads, raised lavage fibronectin and led to grade 1 asbestosis. Among long-term Quebec asbestos miners and millers without radiographically detectable asbestosis, 50% had enhanced gallium-67 lung uptake. In a follow-up, 12 of 16 workers with normal chest radiographs and positive gallium scans progressed to clinical asbestosis. The authors also discussed lung lavage, lung function tests and high-resolution CT (HRCT). They cited a study by Staples and colleagues in which HRCT was abnormal in 57 of 169 exposed workers with normal chest radiographs. The authors wrote that, in their clinical experience, 10% to 20% of long-term exposed workers have HRCT findings suggestive of early asbestosis despite normal radiographs, a figure they were still formally investigating. They called the interpretation of HRCT-only findings controversial but concluded that, in their view, the diffuse character of the abnormalities would support interpreting them as asbestos-induced injury or early asbestosis.

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: Narrative review of the authors' own and others' animal and human research on early asbestosis and its detection
• Who was studied: Reviewed work included rat experiments by other researchers, the authors' sheep model, and the authors' studies of long-term asbestos miners and millers of the Quebec Eastern Townships, plus other investigators' HRCT studies of asbestos-exposed workers
• Exposure: In the sheep experiments, a single exposure to saline, saline plus latex beads, or chrysotile asbestos fibers; in humans, long-term work in asbestos mines and mills
• Main results:
  • In sheep, lavage fibronectin rose only in the asbestos-exposed animals, to levels two to three times above control or latex-exposed sheep
  • In asbestos-exposed sheep, the alveolitis evolved to grade 1 asbestosis, while inflammation in latex-exposed sheep regressed
  • In asbestos workers, lavage fibronectin and procollagen 3 levels were comparable to controls in workers without clinically evident disease, but significantly elevated in those with subclinical or clinical asbestosis
  • Among Quebec asbestos workers without radiographically detectable asbestosis, 50% had enhanced gallium-67 uptake in the lung
  • In a follow-up of 16 asbestos workers with normal chest radiographs and positive gallium scans, 12 progressed to full clinical asbestosis (75%)
  • Cited study by Staples et al (not this article's own data): HRCT was abnormal in 57 of 169 asbestos-exposed workers with normal chest radiographs (33%)
  • In the authors' clinical experience (not yet formally documented), some 10% to 20% of long-term asbestos-exposed workers have HRCT findings suggestive of early asbestosis while their chest radiographs are normal
• The authors' conclusion: The authors concluded that gallium-67 scanning detects early asbestos-induced inflammation, that lavage adds information on the fibrosing character of the disease, and that, in their view, the diffuse character of abnormalities seen only on HRCT would support interpreting them as asbestos-induced injury or early asbestosis
• Limitations the authors state:
  • Use of gallium-67 scanning will be limited by relatively high radiation exposure, workers' fear of injections and radiation, and the need for two clinic visits 48 hours apart
  • Lung lavage is relatively invasive
  • Interpretation of some HRCT signs (subpleural curvilinear lines and densities) varies between readers, and these signs are not specific to asbestosis
  • The 10% to 20% figure reflects the authors' clinical experience; a formal objective investigation was still under way

Topics

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

Medical terms in this study, explained in our Lexicon: Eastern Townships, Macrophage, Platelet-Derived Growth Factor (PDGF), Fibroblast, Collagen, Deposition, Chest X-Ray, High-Resolution CT (HRCT).

Related studies

• Computed tomography in the early detection of asbestosis — R. Bégin, G. Ostiguy, et al. (1993)
• Recent Advances in the Diagnosis of Malignant Mesothelioma: Focus on Approach in Challenging Cases and in Limited Tissue and Cytologic Samples — S. Monaco, M. Mehrad, et al. (2018)
• Dendritic Cells in Human Lung Disease: Recent Advances — J.W. Upham, Y. Xi (2017)
• Increased alveolar plasminogen activator in early asbestosis — A. Cantin, C. Allard, et al. (1989)
• Recent advances in the treatment of malignant pleural mesothelioma — S.S. Ramalingam, C.P. Belani (2008)
• Recent advances in pulmonary cytopathology — S.D. Greenberg (1983)

Browse more research in Seminars in Roentgenology, or return to medical research.