Comparative Study of Genotoxicity in Different Tobacco Related Habits using Micronucleus Assay in Exfoliated Buccal Epithelial Cells

Evaluation of the genetic damage to workers in a Greek shipyard

Shipyards are industrial areas where workers are likely exposed to environmental pollutants such as welding fumes, fine organic solvent and dye dust, that render the occupational environment a high risk one. Assessing the risk that workers are exposed to is a high critical factor in improving their working conditions. The present study aims to investigate the potential genetic damage to workers exposed to a harsh environment in a Greek shipyard. It is focused on assessing the percentage of induced micronuclei, as well as on changes in the various cell types of shipyard workers' oral mucosa epithelium by implementing the buccal micronucleus cytome assay. Exposed workers appeared with statistically significant induced micronuclei as compared to office employees. Statistically, significant cell lesions were detected and are related to workers' exposure to environmental conditions. The workers' smoking habit contributed as well to the observed buccal epithelial cell alterations. The observed data signify the high-risk workers are exposed; resulting in the shipyard's management the need to implement measures improving the working environment conditions and to reevaluate the workers' personal protective equipment requirements.

The Micronuclei Scoring as a Biomarker for Early Detection of Genotoxic Effect of Cigarette Smoking

OBJECTIVE

The main aim of this study is to evaluate the micronuclei scoring as a biomarker for early detection and screening of genotoxic effect of cigarette smoking in the peripheral blood T- lymphocytes.

METHODS

A total number of eligible 148 individuals have participated in the study; 78 Current smokers and 70 never smokers. Cytokinesis-block micronucleus assay was performed for all the participants in the peripheral blood T-lymphocytes. Assessment of the smoking status of the participants was conducted through the detailed smoking history, Fagerström test for nicotine dependence (FTND) scoring, and determination of the urinary cotinine creatinine ratio (CCR).

RESULT

A significantly higher frequency of  micronuclei  in the binucleated T-lymphocytes(BMNi) was identified in the smokers group as compared to the nonsmokers; OR=4.9, 95% CI=1.9-12.5), P-value=0.006. Both of the pack years and the smoking duration of the smokers could significantly predict the BMNi scoring; P-value=0.001, 0.002 respectively.

CONCLUSION

Our results indicate the association between BMNi and cigarette smoking, suggesting that BMNi Scoring can be a useful biomarker for early detection and screening of the genotoxic effect of cigarette smoking as a primary preventive measure for various smoking induced cancers.
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The smokeless tobacco habit and DNA damage: A systematic review and meta-analysis

BACKGROUND

The aim of this systematic review was to evaluate the frequency of micronuclei or other DNA damage in the oral mucosa of adults that have smokeless tobacco habits compared to adults that not have these habits.

MATERIAL AND METHODS

We searched PubMed, Scopus, Web of Science, LILACS, BBO and Cochrane Library and SIGLE. We also surveyed gray literature. We included only clinical trials that compare the frequency of micronuclei or other DNA damage in the oral mucosa of adults that have smokeless tobacco habits compared to adults that not have these habits. Quality assessments of the selected trials were evaluated by two independent reviewers, using the Effective Public Health Practice Project - (EPHPP) with modifications.

RESULTS

After the database screening and removal of duplicates, 2574 studies were identified. After title screening, 172 studies remained, and this number was reduced to 25 after careful examination of the abstracts. The standardized mean difference of the frequency of micronuclei between groups was 1.88, with a 95% confidence interval of 1.40 to 2.36 (p < 0.00001). In all analyses heterogeneity was detected.

CONCLUSIONS

Despite the heterogeneity of studies, the frequency of micronuclei was significant bigger in adults who have the smokeless tobacco habit when compared to those not have this habit. The same occurred with the frequency of binucleated cells, karyolisis and karyorrhexis.

Evaluation of genotoxic effects in Brazilian agricultural workers exposed to pesticides and cigarette smoke using machine-learning algorithms

Monitoring exposure to xenobiotics by biomarker analyses, such as a micronucleus assay, is extremely important for the precocious detection and prevention of diseases, such as oral cancer. The aim of this study was to evaluate genotoxic effects in rural workers who were exposed to cigarette smoke and/or pesticides and to identify possible classification patterns in the exposure groups. The sample included 120 participants of both sexes aged between 18 and 39, who were divided into the following four groups: control group (CG), smoking group (SG), pesticide group (PG), and smoking + pesticide group (SPG). Their oral mucosa cells were stained with Giemsa for cytogenetic analysis. The total numbers of nuclear abnormalities (CG = 27.16 ± 14.32, SG = 118.23 ± 74.78, PG = 184.23 ± 52.31, and SPG = 191.53 ± 66.94) and micronuclei (CG = 1.46 ± 1.40, SG = 12.20 ± 10.79, PG = 21.60 ± 8.24, and SPG = 20.26 ± 12.76) were higher (p < 0.05) in the three exposed groups compared to the GC. In this study, we considered several different classification algorithms (the artificial neural network, K-nearest neighbors, support vector machine, and optimum path forest). All of the algorithms displayed good classification (accuracy > 80%) when using dataset2 (without the redundant exposure type SPG). It is clear that the data form a robust pattern and that classifiers could be successfully trained on small datasets from the exposure groups. In conclusion, exposing agricultural workers to pesticides and/or tobacco had genotoxic potential, but concomitant exposure to xenobiotics did not lead to additive or potentiating effects.

Does smoking habit increase the micronuclei frequency in the oral mucosa of adults compared to non-smokers? A systematic review and meta-analysis

OBJECTIVES

A systematic review of clinical studies to evaluate the frequency of micronuclei in the oral mucosa of smokers and non-smokers in adult patients was performed.

MATERIALS AND METHODS

A comprehensive search was carried out on MEDLINE via PubMeb, Scopus, Web of Science, LILACS, BBO, and Cochrane Library and SIGLE without restrictions. Dissertations and thesis were searched using the ProQuest Dissertations and Periodicos Capes Thesis Databases. We included only cross-sectional clinical trials that compared the frequency of micronuclei in the oral mucosa of smokers and non-smokers in adult patients.

DATA

After the removal of duplicates, 1338 articles were identified. After title and abstract screening, 35 studies remained. Eighteen studies were further excluded, whereas 17 studies remained for qualitative analysis and 16 for the meta-analysis of the primary and secondary outcomes. A significant difference in the frequency of micronuclei in smokers when compared to non-smokers was observed in the present study.

CONCLUSIONS

Despite the high variation in the methodology of the assessed studies, this study showed a higher frequency of micronuclei in exfoliated cells of smokers compared to non-smokers.

CLINICAL SIGNIFICANCE

The use of tobacco is associated with cytotoxic and genotoxic effects because a higher frequency of micronuclei in exfoliated cells of smokers was observed.