Pulmonary fibrosis and ferruginous bodies associated with exposure to synthetic fibers

Our plain-English summary of Pulmonary fibrosis and ferruginous bodies associated with exposure to synthetic fibers, by A.J. Ghio, W. Funkhouser, C.B. Pugh, et al (Toxicologic Pathology, 2006).

The study

• Authors: A.J. Ghio, W. Funkhouser, C.B. Pugh, S. Winters, J.G. Stonehuerner, A.M. Mahar, V.L. Roggli
• Journal: Toxicologic Pathology
• Published: 2006;34(6):723-9
• Type of article: Case report
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Exposure to synthetic fibers with employment in textile mills can be associated with an elevated risk of interstitial lung disease (ILD). A mechanism of injury has not been determined. ILD can follow exposures to inorganic fibers (e.g., asbestos) which are associated with a mobilization of iron and catalysis of an oxidative stress. We describe 2 patients with ILD associated with exposure to synthetic textile fibers who demonstrated carbon-based ferruginous bodies suggesting an in vivo accumulation of iron by synthetic fibers after deposition in the lung. These iron-laden bodies varied from perfectly linear fibers to almost particulate matter. Linear structures were irregularly interrupted by deposition of iron-abundant material. The capacity of these synthetic fibers to complex iron and generate an oxidative stress is confirmed in vitro.

In plain English

This article described two women with interstitial lung disease (scarring of the lung tissue) who had worked for many years in textile mills. It also reported laboratory tests on fibers collected from mill surfaces. It was not a study of asbestos, and neither patient reported asbestos exposure. Patient 1 was 56 and had never smoked. She had spent 20 years grading and inspecting at a mill that used Nylon and Rayon. Patient 2 was 41 and a smoker until she was first seen. She had spent 23 years as a grader at a different mill. Both lung biopsies showed fibrosis, and iron staining showed ferruginous (iron-coated) bodies. In patient 2's lung tissue, 8 of 20 fibers examined were made of carbon and oxygen, and one iron-coated body had formed on a nylon fiber. The other 12 fibers included talc and silica. Fibers collected at the mill looked similar to the lung fibers and gave a comparable chemical pattern. In the laboratory, mill fibers took up iron, and loading them with iron increased oxidant generation. The authors concluded that textile workers with pulmonary fibrosis can potentially show synthetic fibers with ferruginous body formation. They noted that other exposures could also explain the findings.

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: Two case reports, combined with laboratory (in vitro) tests of iron uptake and oxidant generation by fibers collected from a textile mill
• Who was studied: Two African-American women referred with interstitial lung disease: a 56-year-old lifetime nonsmoker who worked 20 years grading and inspecting in a textile mill, and a 41-year-old former smoker who worked 23 years as a grader in a different textile mill
• Exposure: Synthetic textile fibers. Patient 1's mill used Nylon and Rayon; a nylon fiber was identified in patient 2's lung tissue. Patient 1 had no reported employment allowing asbestos or silica exposure, and patient 2 reported no occupational exposure to asbestos, silica or silicates.
• Main results:
  • Patient 1 had restrictive lung function, with a forced vital capacity of 1.35 L (51% predicted). Her thoracoscopic biopsy showed interstitial fibrosis with honeycombing.
  • In patient 1's biopsy, iron (Perls') staining outlined what appeared to be both fibers and particles.
  • Patient 2 had a forced vital capacity of 1.07 L (38% predicted). Her thoracoscopic biopsy showed end-stage fibrotic injury of the lung.
  • Iron staining of patient 2's biopsy showed numerous ferruginous bodies.
  • Patient 2's lung tissue contained 35,000 uncoated fibers per gram of wet lung tissue, counted by scanning electron microscopy.
  • Of 20 consecutive fibers from patient 2's lung analyzed for chemical composition, 8 consisted of carbon and oxygen with no inorganic components.
  • The remaining 12 fibers from patient 2's lung were five talc, two silica, two aluminum silicates, one rutile, one iron (probably the oxide) and one sodium potassium aluminum silicate.
  • Analysis confirmed a ferruginous body associated with a nylon fiber in patient 2's lung tissue.
  • Fibers collected from the textile mill gave a chemical pattern comparable to the fibers isolated from the lung tissue.
  • Mill fibers as collected carried 0.040 µg iron per mg of fiber.
  • The capacity of the mill fibers to take up iron was approximately 9.20 µg per mg of fiber.
  • The authors reported that oxidant generation by the fibers was significantly elevated relative to controls. It increased further after iron loading: absorbance was 0.127 without iron loading and 0.255 with iron loading (Table 1).
  • A radical scavenger (DMTU) and an iron chelator (deferoxamine) each significantly reduced oxidant generation by the textile fibers.
• The authors' conclusion: The authors concluded that textile workers with pulmonary fibrosis can potentially show evidence of synthetic fibers retained in the lung, with ferruginous body formation. They concluded that their laboratory work supports this iron accumulation reflecting a potential oxidative stress in the lower respiratory tract.
• Limitations the authors state:
  • The iron-coated structures might instead reflect other exposures in these patients that disrupted normal iron handling in the lungs.
  • The carbon-based fibers found in the lung may be those inside the ferruginous bodies, or they may come from a second exposure.

Topics

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

Medical terms in this study, explained in our Lexicon: Pulmonary Fibrosis, Ferruginous Bodies, Interstitial Lung Disease, Oxidative Stress, Deposition.

Related studies

• Ferruginous bodies and pulmonary fibrosis in dead low to moderately exposed asbestos cement workers: histological examination — L.G. Johansson, M.P. Albin, et al. (1987)
• Pulmonary fibrosis, carcinoma, and ferruginous body counts in amosite asbestos workers. A study of six cases — V.L. Roggli, S.D. Greenberg, et al. (1980)
• Ferruginous bodies: implications in the mechanism of fiber and particle toxicity — A.J. Ghio, A. Churg, et al. (2004)
• Gender differences in murine pulmonary responses elicited by cellulose nanocrystals — A.A. Shvedova, E.R. Kisin, et al. (2016)
• Agreement between chest radiography and high-resolution computed tomography in diagnosing dust-related interstitial lung fibrosis — R.R. Tiwari (2015)
• Lung dust content in idiopathic pulmonary fibrosis: a study with scanning electron microscopy and energy dispersive x ray analysis — E. Monsó, J.M. Tura, et al. (1991)

Browse more research in Toxicologic Pathology, or return to medical research.