Inducible nitric oxide synthase genetic polymorphism and risk of asbestosis

Our plain-English summary of Inducible nitric oxide synthase genetic polymorphism and risk of asbestosis, by A. Franko, M. Dodič-Fikfak, N. Arnerić, et al (Journal of Biomedicine & Biotechnology, 2011).

The study

• Authors: A. Franko, M. Dodič-Fikfak, N. Arnerić, V. Dolžan
• Journal: Journal of Biomedicine & Biotechnology
• Published: 2011;2011:685870
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Asbestos, a known occupational pollutant, may upregulate the activity of inducible nitric oxide synthase (iNOS) and thus the production of nitric oxide (NO). This study investigated whether iNOS (CCTTT)(n) polymorphism is associated with an increased asbestosis risk in exposed workers. The study cohort consisted of 262 cases with asbestosis and 265 controls with no asbestos-related disease. For each subject the cumulative asbestos exposure data were available. The number of CCTTT repeats was determined following PCR amplification of the iNOS promoter region. Logistic regression was performed to estimate asbestosis risk. The OR of asbestosis was 1.20 (95% CI = 0.85-1.69) for the LL genotype compared to the combined SL and SS genotypes and 1.26 (95% CI = 0.86-1.85) for the LL genotype compared to the SL genotype. The results of this study are borderline significant and suggest a possible role of iNOS (CCTTT)(n) polymorphism in the risk of asbestosis; however, further studies are needed.

In plain English

This nested case-control study from Slovenia asked whether a variation in the gene for inducible nitric oxide synthase (iNOS), an enzyme that makes nitric oxide, was linked to asbestosis. It included 262 workers diagnosed with asbestosis and 265 workers with no asbestos-related disease. The two groups were matched by gender and age. All came from a cohort of 2080 workers exposed to asbestos at the Salonit Anhovo asbestos cement plant. Gene testing succeeded in 258 cases and 259 controls. Workers were grouped by the number of times a short DNA sequence (CCTTT) was repeated, giving short (S) and long (L) forms. The LL genotype was found in 132 cases and 121 controls. The odds ratio for asbestosis was 1.20 (95% CI 0.85 to 1.69) for LL compared with SL and SS combined, and 1.26 (95% CI 0.86 to 1.85) for LL compared with SL. The article reported no significant difference in genotype frequency between the groups. Higher cumulative asbestos exposure was associated with asbestosis; smoking was not. The authors described the results as borderline significant and called for larger studies.

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: nested case-control study (genetic association study)
• Who was studied: 262 workers with asbestosis (cases) and 265 workers with no asbestos-related disease (controls), matched by gender and age. All were selected from a cohort of 2080 workers occupationally exposed to asbestos at the Salonit Anhovo asbestos cement plant, Slovenia, who presented at the State Board for Recognition of Occupational Asbestos Diseases between 1 January 1998 and 31 December 2003. Genotyping succeeded in 258 cases and 259 controls.
• Exposure: Occupational asbestos exposure in asbestos cement manufacturing, measured as cumulative asbestos exposure (fibres/cm3-years) taken from a previous study. This article does not name the fiber types. The genetic factor studied was the number of CCTTT repeats in the iNOS gene promoter.
• Main results:
  • Genotype counts: the LL genotype was found in 132 of 258 cases and 121 of 259 controls; SL in 83 cases and 96 controls; SS in 43 cases and 42 controls.
  • No significant difference was found between cases and controls in the frequency of the LL genotype versus the combined SL and SS genotypes.
  • Odds ratio of asbestosis for the LL genotype compared with the combined SL and SS genotypes: 1.20 (95% CI 0.85 to 1.69).
  • Odds ratio of asbestosis for the LL genotype compared with the SL genotype: 1.26 (95% CI 0.86 to 1.85).
  • Odds ratio of asbestosis for the SL genotype compared with the SS genotype: 0.84 (95% CI 0.50 to 1.42).
  • The odds ratio for LL versus combined SL and SS remained practically unchanged after adjustment for gender, age, smoking and cumulative asbestos exposure.
  • Average cumulative asbestos exposure was 37.67 fibres/cm3-years in cases and 11.23 fibres/cm3-years in controls. The authors reported this difference as statistically significant.
  • With cumulative asbestos exposure logarithmically transformed, the odds ratio of asbestosis was 3.21 (95% CI 2.43 to 4.23).
  • No association was observed between asbestosis and smoking (ever versus never).
• The authors' conclusion: The authors described the results as borderline significant. They concluded that further studies with more subjects are needed to clarify the association between the iNOS polymorphism and asbestosis. They stated that, to their knowledge, this was the first study of this association.
• Limitations the authors state:
  • Some controls might already have had asbestosis that could only be detected by tissue (histopathological) examination. The authors suggested that in that case the association might have been slightly stronger.
  • The authors stated that studies with a larger number of subjects are needed.

Topics

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

Medical terms in this study, explained in our Lexicon: Inducible Nitric Oxide Synthase (iNOS), Asbestos Exposure.

Related studies

• The role of endothelial nitric oxide synthase gene polymorphisms in patients with lung cancer — C. Koçer, N. Benlier, et al. (2020)
• The influence of genetic polymorphisms of GSTP1 on the development of asbestosis — A. Franko, V. Dolzan, et al. (2008)
• Expression of inducible nitric oxide synthase in healthy pleura and in malignant mesothelioma — Y. Soini, K. Kahlos, et al. (2000)
• Early inflammatory response to asbestos exposure in rat and hamster lungs: role of inducible nitric oxide synthase — M. Dörger, A.M. Allmeling, et al. (2002)
• Dual role of inducible nitric oxide synthase in acute asbestos-induced lung injury — M. Dörger, A.M. Allmeling, et al. (2002)
• Heme oxygenase-1 promoter polymorphism is associated with risk of malignant mesothelioma — A. Murakami, Y. Fujimori, et al. (2012)

Browse more research in Journal of Biomedicine & Biotechnology, or return to medical research.