Chromatographic Detection of 8-Hydroxy-2'-Deoxyguanosine in Leukocytes of Asbestos Exposed Workers for Assessing Past and Recent Carcinogen Exposures

Our plain-English summary of Chromatographic Detection of 8-Hydroxy-2'-Deoxyguanosine in Leukocytes of Asbestos Exposed Workers for Assessing Past and Recent Carcinogen Exposures, by F. Cellai, S. Bonassi, A. Cristaudo, et al (Diagnostics, 2020).

The study

• Authors: F. Cellai, S. Bonassi, A. Cristaudo, A. Bonotti, M. Neri, M. Ceppi, M. Bruzzone, M. Milić, A. Munnia, M. Peluso
• Journal: Diagnostics
• Published: 2020;10(4)
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Asbestos fibers include a group of silicate minerals that occur in the environment and are widely employed in occupational settings. Asbestos exposure has been associated to various chronic diseases; such as pulmonary fibrosis; mesothelioma; and lung cancer; often characterized by a long period of latency. Underlying mechanisms that are behind the carcinogenic effect of asbestos have not been fully clarified. Therefore; we have conducted an epidemiological study to evaluate the relationship between 8-hydroxy-2'-deoxyguanosine (8-oxodG), one of the most reliable biomarkers of oxidative stress and oxidative DNA damage; and asbestos exposure in the peripheral blood of residents in Tuscany and Liguria regions; Italy; stratified by occupational exposure to this carcinogen. Levels of 8-oxodG were expressed such as relative adduct labeling (RAL); the frequency of 8-oxodG per 105 deoxyguanosine was significantly higher among exposed workers with respect to the controls; i.e., 3.0 ± 0.2 Standard Error (SE) in asbestos workers versus a value of 1.3 ± 0.1 (SE) in unexposed controls (p < 0.001). When the relationship with occupational history was investigated; significant higher levels of 8-oxodG were measured in current and former asbestos workers vs. healthy controls; 3.1 ± 0.3 (SE) and 2.9 ± 0.2 (SE), respectively. After stratification for occupational history; a significant 194% excess of adducts was found in workers with 10 or more years of past asbestos exposure (p < 0.001). 8-oxodG can be used for medical surveillance programs of cohorts of workers with past and recent exposures to carcinogens for the identification of subjects requiring a more intense clinical surveillance.

In plain English

This cross-sectional study in Italy measured 8-oxodG, a marker of oxidative DNA damage, in white blood cells of 185 men: 98 asbestos workers under health surveillance at University Hospital of Pisa and 87 unexposed blood donors in Genoa. Of the workers, 39 had current potential exposure, mostly in construction, and 59 had past exposure, mostly in chemistry, metal-mechanics and shipbuilding. Fiber type and airborne fiber levels were unknown. Average 8-oxodG per 100,000 deoxyguanosine was 3.0 (standard error 0.2) in workers and 1.3 (0.1) in controls. Adjusted for age, education and smoking, the mean ratio was 2.36 (95% CI 1.99–2.81). Compared with controls, it was 2.43 (1.90–3.12) for current workers, 2.32 (1.88–2.86) for former workers and 2.94 (2.11–4.11) for 16 workers employed 10 or more years. Among workers only, 10 or more years versus 4 or fewer gave 1.34 (0.85–2.10), not statistically significant. Smoking was not significantly associated with 8-oxodG. The authors concluded that measuring 8-oxodG could help identify workers with increased genetic damage. They noted that workers may also have been exposed to other carcinogens.

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: Cross-sectional study comparing a DNA damage marker (8-oxodG, measured by 32P-postlabeling chromatography) in blood leukocytes of asbestos workers and unexposed controls
• Who was studied: 185 men in Italy. The 98 asbestos workers were under a health surveillance program at University Hospital of Pisa, Tuscany: 39 with current potential exposure and 59 with past exposure. The 87 unexposed controls were blood donors at Ospedale Policlinico San Martino, Genoa, Liguria. Workers with mesothelioma, cancer, immune disease, asbestosis or silicosis were excluded.
• Exposure: Occupational asbestos exposure; fiber type and fiber concentrations were not known. Former workers had mainly worked in the chemistry, metal-mechanics and shipbuilding sectors, exposed from 1980 to 1992. Current workers, classed as having current potential exposure, worked in construction and residential building and had been exposed since 1974. Exposure intensity was estimated from the duration and characteristics of occupations. Workers had a mean of 8.5 years of exposure.
• Main results:
  • Average 8-oxodG was 3.0 ± 0.2 (SE) per 10^5 deoxyguanosine in the 98 asbestos workers and 1.3 ± 0.1 (SE) in the 87 controls.
  • After adjustment for age, educational level and smoking, asbestos workers had a mean ratio of 2.36 (95% CI 1.99–2.81) compared with controls. The authors describe this as a 136% excess.
  • Current asbestos workers had an average of 3.1 ± 0.3 (SE) and former asbestos workers 2.9 ± 0.2 (SE). Compared with controls, the mean ratio was 2.43 (95% CI 1.90–3.12) for current workers and 2.32 (95% CI 1.88–2.86) for former workers.
  • The 16 workers employed 10 or more years had an average of 3.5 ± 0.5 (SE), compared with 1.3 ± 0.1 in controls. Their mean ratio versus controls was 2.94 (95% CI 2.11–4.11), described as a 194% excess.
  • Within the workers only, those with 10 or more years of exposure had a mean ratio of 1.34 (95% CI 0.85–2.10, p = 0.197) compared with those with 4 years or less. This was not statistically significant.
  • Across all participants, smoking was not significantly associated with 8-oxodG (smokers versus non-smokers: mean ratio 1.09, 95% CI 0.74–1.60).
  • Across all participants, those with university education had lower 8-oxodG than those with primary education only: 1.3 ± 0.2 (SE) versus 2.3 ± 0.2 (SE), mean ratio 0.65 (95% CI 0.48–0.88).
• The authors' conclusion: The authors concluded that measuring 8-oxodG in asbestos workers can help identify people with increased genetic damage, which they consider to imply a higher risk of lung cancer and other chronic diseases. They suggested it could be used in medical surveillance of workers with past exposure to carcinogens.
• Limitations the authors state:
  • No direct data were available on fiber exposure levels (f/mL-years) or asbestos type. Exposure intensity was estimated from job duration and characteristics.
  • Workers came from varied industries and may also have been exposed to other carcinogens, such as silica dust, heavy metals or polycyclic aromatic hydrocarbons, which could raise 8-oxodG.
  • Control subjects did not have the specific clinical examinations that the workers had.
  • The authors suggest that the many light smokers in the group could explain the lack of a smoking association.

Topics

Medical terms in this study, explained in our Lexicon: Silicate, Asbestos Exposure, Pulmonary Fibrosis, Mesothelioma, Lung Cancer, Latency, Carcinogenic, Biomarker.

Related studies

• 3-(2-deoxy-β-d-erythro-pentafuranosyl)pyrimido[1,2-α]purin-10(3H)-one deoxyguanosine adducts of workers exposed to asbestos fibers — S. Bonassi, F. Cellai, et al. (2017)
• 8-Hydroxy-2'-deoxyguanosine as a marker of oxidative DNA damage related to occupational and environmental exposures — A. Pilger, H.W. Rüdiger (2006)
• Association between 8-hydroxy-2'-deoxyguanosine levels in DNA of workers highly exposed to asbestos and their clinical data, occupational and non-occupational confounding factors, and cancer — B. Marczynski, T. Kraus, et al. (2000)
• 8-hydroxy-2' -deoxyguanosine (8-OHdG): A critical biomarker of oxidative stress and carcinogenesis — A. Valavanidis, T. Vlachogianni, et al. (2009)
• Detection of 8-oxo-2'-deoxyguanosine, a marker of oxidative DNA damage, in culture medium from human mesothelial cells exposed to crocidolite asbestos — Q. Chen, J. Marsh, et al. (1996)
• Urinary 8-oxo-7, 8-dihydro-2'-deoxyguanosine and biopyrrins levels among construction workers with asbestos exposure history — R. Yoshida, Y. Ogawa, et al. (2001)

Browse more research in Diagnostics, or return to medical research.