Serum growth factors in asbestosis patients

Our plain-English summary of Serum growth factors in asbestosis patients, by Y. Li, A. Karjalainen, H. Koskinen, et al (Biomarkers, 2009).

The study

• Authors: Y. Li, A. Karjalainen, H. Koskinen, H. Vainio, E. Pukkala, K. Hemminki, P.W. Brandt-Rauf
• Journal: Biomarkers
• Published: 2009;14(1):61-6
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Various growth factors, including platelet-derived growth factor (PDGF) and transforming growth factor (TGF)-beta, have been implicated in the pathogenesis of asbestos-induced disease. PDGF and TGF-beta levels were determined by enzyme-linked immunosorbent assays in the banked serum samples of a cohort of workers with asbestosis, and the relationships of the growth factor levels to the subsequent development of cancer and to the radiographic severity and progression of asbestosis in the cohort were examined. Serum levels of PDGF and TGF-beta were found to be unrelated to the development of cancer, and serum levels of PDGF were found to be unrelated to the severity and progression of asbestosis. However, serum levels of TGF-beta were found to be statistically significantly related to disease severity (p = 0.01), increasing approximately 2.4-fold from ILO radiographic category 0 to category 3, and they were marginally related to disease progression (p = 0.07), in multivariate analysis controlling for other contributory factors including cumulative asbestos exposure. This suggests that serum TGF-beta may be a useful biomarker for asbestos-induced fibrotic disease.

In plain English

This study measured two growth factors, platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta), in stored blood serum from 82 Finnish workers with compensable asbestosis (74 men, 8 women). They came from a cohort assembled in Helsinki in 1978–79. Serum and chest X-rays were collected on return visits from 1980 to 1988, and the X-rays were graded on the ILO scale. Cancer was followed through the Finnish Cancer Registry to the end of 2001. By then there had been 33 cancers, including 20 lung cancers and three mesotheliomas. Neither growth factor differed meaningfully between those who did and did not develop cancer. PDGF was not related to asbestosis severity or progression. Average TGF-beta levels rose from 9.8 ng/ml in X-ray category 0 to 23.4 ng/ml in category 3 (p = 0.04). After adjusting for age, sex, smoking and cumulative asbestos exposure, the link with severity remained statistically significant (p = 0.01). The link with progression approached, but did not reach, significance (p = 0.07). The authors concluded that serum TGF-beta levels were correlated with the state of the lung disease in people with 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: Cohort study using banked (stored) serum samples and repeated chest radiographs, with cancer follow-up through a national registry
• Who was studied: 82 of 115 compensable asbestosis cases assembled in 1978–79 at the Finnish Institute of Occupational Health, Helsinki, Finland. The group was 74 men and 8 women, with an average age of 65 at the end of sample collection in 1988. There were 218 chest radiographs and 187 serum samples, collected 1980–88. The group included 16 never-smokers and 66 current or ex-smokers.
• Exposure: Occupational asbestos exposure averaging 20 years in jobs such as asbestos mining, asbestos insulation, asbestos spraying and asbestos cement manufacturing. Average estimated cumulative exposure was 523 fibre-years/ml (range 14–1750). Fiber types are not specified.
• Main results:
  • By 31 December 2001, the 82 subjects had developed 33 cancers: 20 lung cancers, three mesotheliomas and 10 others.
  • Serum TGF-beta and PDGF levels before cancer diagnosis did not vary meaningfully by cancer status. TGF-beta averaged 12.9 ng/ml without cancer vs 14.2 ng/ml with cancer; PDGF averaged 16.1 vs 16.2 ng/ml.
  • Serum PDGF did not vary meaningfully by radiographic severity: 18.6, 16.0, 16.9 and 19.0 ng/ml in major categories 0 to 3 (p = 0.59). It also did not vary by progression: 16.9 ng/ml without vs 16.4 ng/ml with progression (p = 0.73). None of these differences were statistically significant.
  • Serum TGF-beta rose with radiographic severity: 9.8 ng/ml in category 0 (n = 9), 13.3 in category 1 (n = 43), 15.0 in category 2 (n = 25) and 23.4 in category 3 (n = 5). This difference was statistically significant (p = 0.04).
  • Serum TGF-beta was 13.0 ng/ml in the 51 subjects without radiographic progression and 15.3 ng/ml in the 31 with progression. This difference was not statistically significant (p = 0.21).
  • In the multivariate model controlling for age, gender, smoking status and cumulative asbestos exposure, TGF-beta remained statistically significantly associated with radiographic severity: p = 0.01 by major category and p = 0.03 by subcategory.
  • In the multivariate model, the association of TGF-beta with radiographic progression approached, but did not reach, statistical significance (p = 0.07).
  • 31 of the 82 subjects (38%) showed radiographic progression of asbestosis during follow-up. None showed regression.
• The authors' conclusion: The authors concluded that serum TGF-beta levels are correlated with the state of pneumoconiosis in people with asbestosis. They suggested that measuring it may help monitor the disease and identify high-risk individuals.

Topics

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

Medical terms in this study, explained in our Lexicon: Platelet-Derived Growth Factor (PDGF), Disease Progression, Multivariate Analysis, Asbestos Exposure, Biomarker.

Related studies

• Serum oncoproteins and growth factors in asbestosis and silicosis patients — P.W. Brandt-Rauf, S. Smith, et al. (1992)
• Rat pleural mesothelial cells adapted to serum-free medium as a model for the study of growth factor effects — E. Bermudez, B. Libbus, et al. (1998)
• Immunohistochemical localization of transforming growth factor-beta and insulin-like growth factor-I in asbestosis in the sheep model — T.C. Lee, L.I. Gold, et al. (1997)
• Differential proliferation of rat lung fibroblasts induced by the platelet-derived growth factor-AA, -AB, and -BB isoforms secreted by rat alveolar macrophages — J.C. Bonner, A.R. Osornio-Vargas, et al. (1991)
• Relationship of fiber surface iron and active oxygen species to expression of procollagen, PDGF-A, and TGF-beta(1) in tracheal explants exposed to amosite asbestos — J. Dai, A. Churg (2001)
• Chrysotile asbestos upregulates gene expression and production of alpha-receptors for platelet-derived growth factor (PDGF-AA) on rat lung fibroblasts — J.C. Bonner, A.L. Goodell, et al. (1993)

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