Investigation of micronucleus frequencies in lymphocytes of inhabitants environmentally exposed to chrysotile asbestos

Our plain-English summary of Investigation of micronucleus frequencies in lymphocytes of inhabitants environmentally exposed to chrysotile asbestos, by H. Dönmez-Altuntas, M. Baran, F.S. Oymak, et al (International Journal of Environmental Health Research, 2007).

The study

• Authors: H. Dönmez-Altuntas, M. Baran, F.S. Oymak, Z. Hamurcu, N. Imamoğlu, M. Ozesmi, H. Demirtas
• Journal: International Journal of Environmental Health Research
• Published: 2007;17(1):45-51
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Exposure to asbestos minerals has been associated with a wide variety of adverse health effects including lung cancer, pleural mesothelioma, and cancer of other organs. Many of the regions of Turkey have asbestos deposits. People in Doğanli village - one of these regions - have been environmentally exposed to chrysotile asbestos since they were born. In this study the effects of asbestos on micronucleus (MN) frequencies of inhabitants exposed to chrysotile asbestos have been examined. Thirty subjects who had been environmentally exposed to chrysotile asbestos and living in Doğanli village, and 25 controls were studied to assess the MN frequency. The control group was selected from healthy individuals with no exposure to asbestos and living in similar geographic conditions to Doğanli village. Peripheral blood samples were collected from each subject and cultured for MN assay. Cytochalasin-B was added to lymphocyte cultures for evaluation of MN in binucleated (BN) cells. The differences between those exposed to chrysotile asbestos and controls were not statistically significant in terms of BN cells with MN (p > 0.05). There was not a significant relationship between MN frequencies and age, sex, smoking, both in chrysotile asbestos-exposed subjects and in controls (p > 0.05). Although the detection of calcified pleural plaques found in the inhabitants has indicated environmental exposure to chrysotile asbestos, our results show that chrysotile asbestos was not an inducer of MN in subjects exposed to chrysotile asbestos.

In plain English

This study looked for chromosome damage in the blood of villagers environmentally exposed to chrysotile asbestos since birth. In Doğanlı village, Sivas, Turkey, soil containing chrysotile was used to paint and plaster houses and insulate fireplaces until villagers stopped in the last decade. The authors compared 30 people living there since birth (22 women, 8 men, mean age 59.97 years) with 25 unexposed controls from a farming village in Kayseri. Lymphocytes (white blood cells) were cultured, and 1000 binucleated cells per person were checked for micronuclei. These are small extra nuclei formed during cell division from lagging whole chromosomes or chromosome fragments. The mean percentage of binucleated cells with micronuclei was 1.03 (standard deviation 0.52) in exposed villagers and 1.00 (0.49) in controls, a difference that was not statistically significant (p = 0.946). Age, sex and smoking showed no significant relationship with micronucleus frequency in either group, though each group had only three smokers. The authors concluded that micronucleus frequencies were not increased in the exposed villagers. They suggested DNA repair after exposure ended as a possible explanation and called for further 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: Comparison study (exposed group versus unexposed controls) measuring micronucleus frequency in cultured blood lymphocytes
• Who was studied: 30 exposed residents of Doğanlı village (270 inhabitants), Sivas, Turkey, who had lived there since birth: 22 women and 8 men, mean age 59.97 years (range 32 to 80), 27 non-smokers and 3 smokers. 25 controls from a village of Kayseri with no asbestos exposure: 15 women and 10 men, mean age 54.80 years (range 33 to 77), 22 non-smokers and 3 smokers. The study dates are not given.
• Exposure: Environmental and household exposure since birth to chrysotile asbestos in local soil, used to paint and plaster walls and floors and to insulate fireplaces. Villagers stopped using it in the last decade. No exposure measurements are reported.
• Main results:
  • The mean percentage of binucleated cells with any micronuclei was 1.03 (standard deviation 0.52) in the 30 exposed villagers and 1.00 (standard deviation 0.49) in the 25 controls, p = 0.946. This was not a significant increase.
  • No significant differences between exposed villagers and controls were found for binucleated cells with 1 micronucleus (0.84 versus 0.72 percent, p = 0.388), 2 micronuclei (0.14 versus 0.20 percent, p = 0.235), or 3 or 4 micronuclei (p = 1.000).
  • There was no significant relationship between micronucleus frequency and age, sex or smoking, either in the exposed villagers or in the controls (p greater than 0.05).
• The authors' conclusion: The authors concluded that micronucleus frequencies were not increased in inhabitants environmentally exposed to chrysotile asbestos. They suggested that DNA repair after exposure ended might explain this, and said further studies are required.
• Limitations the authors state:
  • The authors attributed the lack of a smoking effect on micronucleus frequency probably to the small number of smokers (three in each group).

Topics

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

Medical terms in this study, explained in our Lexicon: Chrysotile, Asbestos, Lung Cancer, Pleural Mesothelioma, Pleural Plaques, Environmental Exposure.

Related studies

• Reduction of chrysotile asbestos-induced genotoxicity in human peripheral blood lymphocytes by garlic extract — K. Bhattacharya, S. Yadava, et al. (2004)
• Validity of the Lymphocyte Cytokinesis-Block Micronucleus Assay (L-CBMN) as biomarker for human exposure to chemicals with different modes of action: A synthesis of systematic reviews — M. Kirsch-Volders, M. Fenech, et al. (2018)
• Mitotic disturbances and micronucleus induction in Syrian hamster embryo fibroblast cells caused by asbestos fibers — E. Dopp, J. Saedler, et al. (1995)
• Elevated micronucleus frequencies in patients with pleural plaque secondary to environmental exposure to asbestos — M. Gövercin, A.G. Tomatır, et al. (2014)
• Exposure to asbestos: correlation between blood levels of mesothelin and frequency of micronuclei in peripheral blood lymphocytes — V. Marini, L. Michelazzi, et al. (2011)
• Chromosomal aberrations induced by chrysotile and crocidolite in human lymphocytes in vitro — F. Valerio, M. de Ferrari, et al. (1983)

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