Evaluation of micronuclei, cytomorphometric and cytologic changes of the oral mucosa in hookah and cigarette smokers

OBJECTIVE

To analyze the effect of hookah and cigarettes on the oral mucosa of smokers through the use of exfoliative cytology.

STUDY DESIGN

Smear samples were collected by exfoliative cytology from the tongue of 33 hookah smokers, 22 cigarette smokers, and 30 non-smokers. The selected analyses include micronuclei (MN), metanuclear anomalies, epithelial maturation, and cytomorphology (nuclear area [NA], cytoplasmic area [CA], and NA/CA ratio).

RESULTS

The largest differences observed for MN and metanuclear anomalies were between cigarette smokers and the control group (notably 1 MN P = .04; total cells with MN P = .039; total MN P = .042; karyorrhexis and binucleation, P = .0001). The hookah group, compared with the control group, showed the greatest differences for karyolysis (P = .0023), binucleation (P = .0003), and broken egg (P = .008). Significant differences were found between the smokers and the control groups regarding changes in the superficial cell without nucleus, perinuclear halo, vacuolization, color change, mucus, and keratohyalin granules. There was a significant increase in the NA and NA/CA ratio in the smoker groups.

CONCLUSION

This study showed that a combined analysis of exfoliative cytology associated with other diagnostic methods is a useful tool for studying oral carcinogenesis. Hookah and cigarettes showed similar effects in terms of displaying substantial cytogenetic and cytotoxic damage.

Amelioration of Cytogenotoxic Damage in Drug Abusers Supplemented with Folic Acid

BACKGROUND

Cytogenotoxic damage caused by the consumption of legal and illegal drugs in drug abusers has been demonstrated, primarily due to alterations in their antioxidant capacity, cellular repair mechanisms, and increased production of free radicals. Folic acid shows antioxidant activity by acting as a reducing agent, neutralizing present free radicals, and reducing genomic damage.

METHODS

The intervention involved administering 15 mg of folic acid, divided into three doses per day, to a group of 44 drug abusers. The frequency of nuclear abnormalities (NAs) was determined; micronuclei (MNs), nuclear buds (NBUDs), binucleated cells (BNs), abnormally condensed chromatin (CC), karyorrhexis (KX), pyknotic nuclei (PNs), and karyolysis (KL) were determined at different pre-treatment (baseline) and post-treatment time points at 15 and 30 days. Additionally, a group of 44 healthy individuals was used as the control group.

RESULTS

We observed a statistically significant decrease in the frequency of NAs in the drug abuser group (28.45 ± 17.74 before supplementation vs. 11.18 ± 7.42 at 15 days and 9.11 ± 10.9 at 30 days of supplementation). Specifically, it decreased the frequency of NBUDs, BNs, CC, KX, and PNs (p < 0.05).

CONCLUSION

Our study demonstrates a clear improvement in cytogenotoxic damage in drug abusers supplemented with folic acid.

The buccal micronucleus cytome assay: New horizons for its implementation in human studies

In this report we provide a summary of the presentations and discussion of the latest knowledge regarding the buccal micronucleus (MN) cytome assay. This information was presented at the HUMN workshop held in Malaga, Spain, in connection with the 2023 European, Environmental Mutagenesis and Genomics conference. The presentations covered the most salient topics relevant to the buccal MN cytome assay including (i) the biology of the buccal mucosa, (ii) its application in human studies relating to DNA damage caused by environmental exposure to genotoxins, (iii) the association of buccal MN with cancer and a wide range of reproductive, metabolic, immunological, neurodegenerative and other age-related diseases, (iv) the impact of nutrition and lifestyle on buccal MN cytome assay biomarkers; (v) its potential for application to studies of DNA damage in children and obesity, and (vi) the growing prospects of enhancing the clinical utility by automated scoring of the buccal MN cytome assay biomarkers by image recognition software developed using artificial intelligence. The most important knowledge gap is the need of prospective studies to test whether the buccal MN cytome assay biomarkers predict health and disease.

Evaluation of Cytotoxic and Genotoxic Effects in Buccal Mucosal Cells in Non-Smokers and Users of Traditional Combustible Tobacco Products and Non-Combustible Alternatives

AIMS/OBJECTIVES

The aim of this cross-sectional observational study was to investigate cytogenetic damage to the buccal mucosa in non-smokers and consumers of traditional combustible tobacco products and non-combustible alternatives.

METHODS

A total of 160 participants were divided into four groups according to the type of product used, including non-smokers, users of conventional combustible tobacco (cigarettes), heated tobacco, and electronic, tobacco-free vapor products (e-cigarettes). Buccal mucosa samples were analyzed using the micronucleus cytome assay to assess cytotoxic and genotoxic damage.

RESULTS

E-cigarette users showed significantly higher values for all tested parameters in the micronucleus test compared to non-smokers (p < 0.05). Similarly, users of tobacco heating products showed an increase in all parameters (p < 0.05), with the exception of the number of cells with micronuclei. Conventional cigarette smokers showed a notable increase in the number of binucleated cells and cells with karyorrhexis and karyolysis (p ≤ 0.05). When assessing the differences between users of traditional combustible tobacco products and non-combustible alternatives, these did not appear to be significant, except for e-cigarette users, who had significantly more cells with condensed chromatin (p ≤ 0.001), while users of tobacco heating products had more pyknotic cells (p ≤ 0.001).

CONCLUSION

The results of this study underscore the heightened occurrence of cytotoxic and genotoxic damage in users of both conventional combustible tobacco products and non-combustible alternatives compared to non-smokers, emphasizing the detrimental impact of these products on the oral mucosa.

Cytogenotoxicity effects in addicts with multidrug consumption

Drug abuse is considered a global health problem with serious social impact. In recent decades, changes in drug consumption patterns have shown a clear rising trend in the use of multiple drugs. Although the buccal micronucleus cytome (BMCyt) assay has evaluated cytotoxicity in drug abuse, there has not been an approach that takes into account this pattern of multiple drug use. Therefore, in this study, we evaluate for the first time the cytogenotoxic effects in multidrug users, and its correlation with the amount consumed and years of abuse. This study was conducted on 166 individuals by the BMCyt assay. A total of 83 individuals with a history of multiple licit (alcohol and tobacco) and at least one illicit drug abuse (marijuana, methamphetamines, cocaine, and/or inhalants), and 83 healthy individuals, non-drug abusers were analyzed. The results showed that drug abusers had higher frequencies of nuclear abnormalities nuclear buds, binucleated cells, pyknotic nuclei (PNs), karyorrhexis (KX), and abnormally condensed chromatin when compared with healthy controls. Moreover, results suggests that the use of licit and illicit drugs is related to cytogenotoxic damage, as was shown by an upward trend in the frequency of nuclear abnormalities identified in groups 1 (alcohol + tobacco + at least one illicit drug) and 2 (tobacco + at least one illicit drug). Furthermore, a positive correlation was found in the different groups, between the years and the amount of consumption of some drugs (alcohol, methamphetamine, and tobacco) with cytotoxicity markers such as KL, KX, and PNs.

The influence of smoking on the effectiveness of at-home bleaching: A prospective clinical study

OBJECTIVES

To evaluate the effect of smoking on tooth whitening and color change after at-home bleaching.

MATERIALS AND METHODS

This prospective clinical study evaluated two groups of participants: NS-non-smokers (n = 24) and S-smokers (n = 16). All subjects were treated with at-home bleaching using 22% carbamide peroxide (CP) for 1 h/day for 14 days. Color coordinates (L*-luminosity, a*-red-green axis and b*-yellow-blue axis) were obtained before bleaching (D0-baseline), 1 day (D1), 15 days (D15), and 1 month (D30) after bleaching. The whiteness index (WID ) and CIEDE2000 color differences (ΔE00 ) were calculated for S and NS. Color changes between S and NS subjects for specific teeth (CI-Central Incisors, LI-Lateral Incisors, and C-Canines) were analyzed using the Mann-Whitney test (α = 0.05).

RESULTS

There was no significant difference in WID between S and NS subjects at baseline. NS participants showed higher WID than S at D1, D15, and D30 (p < 0.05). NS showed higher ΔWID for CI and C between D0 and the other evaluation times (D1, D15, and D30) compared to S. Smokers showed higher darkening of CI than NS in ΔWID D30-D1 (p < 0.05). Color changes showed similar overall behavior for ΔWID . For all evaluation times, ΔWID and ΔE00 values were below the corresponding acceptability thresholds.

CONCLUSION

At-home bleaching was effective on smokers and nonsmokers. Smoking negatively affected color stability after bleaching. ΔE00 and ΔWID were acceptable for both groups.

CLINICAL SIGNIFICANCE

Although smoking negatively affected color stability after bleaching, the observed changes were clinically acceptable.

Recommendations and quality criteria for micronucleus studies with humans

Micronucleus (MN) analyses in peripheral blood lymphocytes and exfoliated cells from different organs (mouth, nose, bladder and cervix) are at present the most widely used approaches to detect damage of genetic material in humans. MN are extranuclear DNA-containing bodies, which can be identified microscopically. They reflect structural and numerical chromosomal aberrations and are formed as a consequence of exposure to occupational, environmental and lifestyle genotoxins. They are also induced as a consequence of inadequate intake of certain trace elements and vitamins. High MN rates are associated with increased risk of cancer and a range of non-cancer diseases in humans. Furthermore, evidence is accumulating that measurements of MN could be a useful tool for the diagnosis and prognosis of different forms of cancer and other diseases (inflammation, infections, metabolic disorders) and for the assessment of the therapeutic success of medical treatments. Recent reviews of the current state of knowledge suggest that many clinical studies have methodological shortcomings. This could lead to controversial findings and limits their usefulness in defining the impact of exposure concentrations of hazardous chemicals, for the judgment of remediation strategies, for the diagnosis of diseases and for the identification of protective or harmful dietary constituents. This article describes important quality criteria for human MN studies and contains recommendations for acceptable study designs. Important parameters that need more attention include sufficiently large group sizes, adequate duration of intervention studies, the exclusion of confounding factors which may affect the results (sex, age, body mass index, nutrition, etc.), the evaluation of appropriate cell numbers per sample according to established scoring criteria as well as the use of proper stains and adequate statistical analyses.

Cytological Screening Model of Normal Oral Mucosa Exposed to Carcinogens: A Pilot Study

INTRODUCTION

Oral cytopathology is able to detect incipient cellular alterations, but it is not routinely applied to this purpose. We aimed to establish a model to screen individuals with no oral lesion exposed to smoking/alcohol, by means of the nuclear area, cell proliferation rate, and analysis of genetic damage.

METHODS

In this cross-sectional pilot study, 90 patients were allocated into 3 groups: oral cancer group (patients with oral squamous cell carcinoma), tobacco/alcohol group (patients without oral lesions and exposed to these risk factors), and control group (individuals with no lesion and not exposed to tobacco and alcohol). The cytological smears performed in these individuals were stained with Papanicolaou, a silver-staining and a Feulgen reaction. The nuclei of cells were measured, and AgNORs/nucleus and micronuclei (MN) were quantified. The cutoff values were stipulated evaluating the healthy mucosa (control group) and the cancerization field mucosa (oral cancer group).

RESULTS

Cutoff values for the screening of individuals exposed to carcinogens were ≥8% of nuclei larger than 100 μm2, ≥3.38 AgNOR/nucleus, and ≥3 MN per 1,000 cells.

CONCLUSIONS

Nuclear area measurement and AgNORs/nucleus and MN quantification identified the incipient phase of oral carcinogenesis. A screening model for individuals without oral lesion exposed to smoking/alcohol was proposed.

E-cig might cause cell damage of oral mucosa

OBJECTIVE

The aim of this study was to investigate cytogenetic and cytotoxic damage through the evaluation of micronuclei (MN) and metanuclear anomalies in the oral mucosa of electronic cigarette (e-cig) users.

STUDY DESIGN

The patients were recruited into 4 groups: e-cig users, smokers, former smokers, and nonsmokers (control). The samples were collected by means of exfoliative cytology of the lateral region of the tongue and the floor of the mouth. The smears obtained were fixed and stained by the Feulgen method for investigation of MN and metanuclear anomalies.

RESULTS

A significant difference was observed for MN frequency only between the smoker and control groups. As for metanuclear anomalies, significant differences were observed: karyolysis between: smokers and control, e-cig and control, as well as former smokers; karyorrhexis: between smoker and control; binucleation: between e-cig and former smoker, as well as control; broken eggs: between e-cig and all other groups; nuclear bud: between e-cig and former smokers, as well as control.

CONCLUSIONS

E-cig and alcohol users presented genotoxicity and cytotoxicity in the oral mucosa cells. The use of e-cigs and alcohol by former smokers can cause more damage to the cells of the oral mucosa compared to those who have not used e-cigs.

Association between DNA ploidy and micronucleus frequency in chronic smokers and impact of smoking cessation

Tobacco use may initiate the process of oral carcinogenesis with clinically undetectable changes. Smoking cessation may prevent its progression. The objective of this study was to evaluate the association between DNA ploidy and micronucleus (MN) frequency in chronic smokers. Three groups were evaluated: Smoker Group, Former Smoker Group and Control Group. Exfoliative cytology was performed on the lateral border of the tongue and mouth floor. MN and DNA ploidy analyses were performed, as well as the correlation between the variables. The data showed a difference between the groups for the total MN (p = 0.0227), and the Smoker group had the highest mean (4.22 ± 4.12). The three groups did not differ statistically from each other on ploidy evaluation (p-value > 0.05). There was also an association between aneuploidy and increased MN frequency in the Former Smoker group (p = 0.0036). In conclusion, these results point out that there is a relationship between the frequency of MN and aneuploidy in former smokers. Moreover, smoking cessation, even for a short period of time, may promote the decrease of MN frequency caused by tobacco use.

Early genotoxic damage through micronucleus test in exfoliated buccal cells and occupational dust exposure in construction workers: a cross-sectional study in L'Aquila, Italy

AIM

The city of L'Aquila (central Italy) was hit by a strong earthquake in 2009 that caused the collapse of several buildings, deaths and injured people. In the following years, a great number of building sites were activated, building workers resulted intensely exposed and represent a relevant target for research on environmental mutagenesis and epidemiological surveillance. Cells of buccal mucosa are considered an appropriate site for early detecting of cytogenetic damage, since it represents the first barrier in inhalation or ingestion and can metabolize carcinogenic agents into reactive chemicals. Our study is aimed 1) at comparing the early genotoxic damage as measured by the buccal mucosa micronucleus test in two subgroups of workers defined by different occupational exposure and 2) at evaluating possible confounding variables such as lifestyle factors.

METHODS AND RESULTS

A cross-sectional study was conducted in L'Aquila, on 24 outdoor workers (OWs) highly exposed on the construction sites and 26 indoor workers (IWs), all subjected to the compulsory occupational surveillance system, in the period 2017-2018. Buccal cells samples were collected and, based on the Micronucleus test, the exfoliated cells were classified in respect of nuclear changes observed. Moreover, a self-report questionnaire composed of 84 items, was administered to the workers.

RESULTS

Significant differences were observed between Exp⁺ (OWs) and Exp^- (IWs) in the number of the analyzed cells (expressed as mean value out of 1000 cells): respectively 954.46 vs 990.06 normal cells, (p < 0.001); 19.79 vs 4.95 micronucleated cells, as marker of chromosomal damage (p < 0.001); 13.93 vs 8.96 binucleated cells, as marker of failed cytokinesis (p < 0.001); 2.09 vs 1.18 karyolytic cells, as marker of cell death and damaged DNA (p < 0.05). According with a multivariate regression analysis, in addition to the job exposure (OW vs IW, beta = 12.221, p < 0.001), the only variable independently associated with an increase in Micronuclei (MNs) is the smoking habit (OWs vs IWs, beta = 6.683, p < 0.001) which, even if not associated with dust exposure, worsens cell integrity. Moreover, this worsening effect is weaker in workers not exposed to the site dust (moderation effect). Within social demographic factors, the high educational level only apparently seems to affect MNs number: even if unbalanced in favor of IWs vs OWs, this variable resulted a confounder, since its effect disappears when the interaction between these two factors is considered, because it is a covariate of smoking habit as well as of the job condition.

CONCLUSION

Despite some limitation, our findings clearly confirm the role of occupational exposure as a marker of cytogenetic damage associated with MNs number in construction workers. Moreover, smoking status appears as the only other investigated factor independently associated to the outcome. The statistical model, in addition, highlights possible moderation and confounding effects, such as interaction between smoking and occupational exposure and the unbalanced school education level in workers. Micronucleus test in exfoliated buccal cells would be considered a suitable method for studying the early genotoxic damage in the construction occupational setting as well as in evaluating the efficacy of preventive practices.

Genomic Instability in Peripheral Blood and Buccal Mucosal Cells of Marijuana Smokers: The Impact of Tobacco Smoke

BACKGROUND

The aim of this study was to evaluate cytotoxic, mutagenic and genotoxic effects on buccal mucosa and peripheral blood cells from marijuana and tobacco smokers.

METHODS

For this purpose, a total of 45 volunteers were distributed into four groups: CTRL group (control): individuals who did not smoke marijuana or tobacco (n = 11); Group M: Marijuana smokers (n = 13); Group T: Tobacco smokers (n = 13); Group M + T: Smokers of both marijuana and tobacco (n = 08).

RESULTS

Smokers of both marijuana and tobacco led an increase of micronucleated cells on buccal mucosa when compared to control group. The occurrence of karyolysis showed significant changes in this group as well. The comet assay data revealed genetic damage in peripheral blood cells for all groups of smokers.

CONCLUSION

In summary, our results showed that marijuana and /or tobacco are able to induce genetic damage and cytotoxicity in oral and peripheral blood cells.

Smoking causes induction of micronuclei and other nuclear anomalies in cervical cells

INTRODUCTION

Smoking is an independent cause of cervical cancer, which is the 4th most common malignancy in women. It is currently not known if tobacco consumption causes chromosomal damage (which is a hallmark of human cancer) in cervical cells and if age and the hormonal status have an impact on tobacco induced genetic instability in the cervix.

METHODS

We conducted a study with pre- and post-menopausal women smokers and never-smokers (25/group). Smokers consumed 30 light/medium cigarettes/day and were matched with the non-smoking group. Cervical cells were analyzed for induction of micronuclei (MN) which are caused by structural/numerical chromosomal aberrations; additionally, other nuclear anomalies reflecting genomic instability and cytotoxicity were scored. Furthermore, the frequencies of basal cells were recorded which reflect the mitotic activity of the mucosa.

RESULTS

MN and other abnormalities were increased in both groups of smokers. The effects were most pronounced in postmenopausal smokers (i.e. 2-fold higher) compared to premenopausal smokers. Also the number of basal cells (indicative for cell proliferation) was clearly enhanced in older women. Tar and nicotine had no detectable impact on chromosomal damage but a clear association with pack-years was observed.

CONCLUSIONS

Smoking increased chromosomal instability, cytotoxicity and induced cell divisions in cervical mucosa cells of pre- and post-menopausal women. The effects were more pronounced in the latter group indicating a higher risk for diseases (including cancer) that are causally related to DNA damage.

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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Occupational exposure to formaldehyde and early biomarkers of cancer risk, immunotoxicity and susceptibility

Formaldehyde (FA) is a high-volume production chemical manufactured worldwide to which many people are exposed to both environmentally and occupationally. FA was recently reclassified as a human carcinogen. Several epidemiological studies have revealed an increased risk of cancer development among workers exposed to FA. Although FA genotoxicity was confirmed in a variety of experimental systems, data from human studies are conflicting. The aim of the present study was to evaluate the occupational exposure to FA in a multistage approach relating the exposure with different biomarkers (dose and effect) and individual susceptibility. Air monitoring was performed to estimate the level of exposure to FA during shift work. Eighty-five workers from hospital anatomy-pathology laboratories exposed to FA and 87 controls were tested for cytogenetic alterations in lymphocytes (micronucleus, MN; sister-chromatid exchange, SCE) and T-cell receptor (TCR) mutation assay. The frequency of MN in exfoliated buccal cells, a first contact tissue was also assessed. Percentages of different lymphocyte subpopulations were selected as immunotoxicity biomarkers. The level of formic acid in urine was investigated as a potential biomarker of internal dose. The effects of polymorphic genes of xenobiotic metabolising enzymes and DNA repair enzymes on the endpoints studied were determined. The mean level of FA exposure was 0.38 ± 0.03 ppm. MN (in lymphocytes and buccal cells) and SCE were significantly increased in FA-exposed workers compared to controls. MN frequency positively correlated with FA levels of exposure and duration. Significant alterations in the percentage of T cytotoxic lymphocytes, NK cells and B lymphocytes were found between groups. Polymorphisms in CYP2E1, GSTP1 and FANCA genes were associated with increased genetic damage in FA-exposed subjects. The obtained information may provide new important data to be used by health and safety care programs and by governmental agencies responsible for setting the acceptable levels for occupational exposure to FA.

Assessment of the nuclear medicine personnel occupational exposure to radioiodine

PURPOSE

To physically and cytogenetically screen medical personnel of Department of Endocrinology and Nuclear Medicine, Holy Cross Cancer Center, Kielce, Poland (DENM) who are occupationally exposed to ¹³¹I.

MATERIALS AND METHODS

The exposure was monitored by whole-body and finger ring dosimeters. The thyroid iodine intake was measured by a whole-body spectrometer equipped with two semiconductor gamma radiation detectors. A cytokinesis-block micronucleus assay and the premature chromosome condensation technique were used to assess the aberration score. Cytogenetic analyses were carried out on a group of 29 workers and were compared to 32 controls (healthy donors), matched for gender and age.

RESULTS

On average, the exposed group showed a significantly higher frequency of genetic damage and a higher proliferation index compared to the control group. Smoking status, age and duration of exposure influenced the observed effects in both groups. No differences in measured biomarkers were observed after stratification of the exposed group into two subgroups based on the measured ¹³¹I activity below and above 6 Bq.

CONCLUSION

The findings suggest that radiation protection principles based on whole-body and finger ring dosimetry, supported by activity measurements with a whole-body spectrometer, may be insufficient to monitor the absorbed dose estimation of the nuclear medicine staff who are occupationally exposed to ¹³¹I. Furthermore, their future health risks are influenced by confounders. Direct assessments comparing physical and biological dose estimations on the larger group are needed to accurately monitor occupational radiation exposure.

Results of buccal micronucleus cytome assay in pesticide-exposed and non-exposed group

Since many different pesticides have been used occupationally, there have been inconsistent results regarding DNA damages among greenhouse workers. Thus, the aim of the study is to evaluate DNA damages, cell death, and chromosomal instability by using the buccal micronucleus cytome (BMcyt) assay in greenhouse workers and to compare those with a non-exposed group. The BMcyt assay was applied to the exfoliated buccal cell samples collected from 66 pesticide-exposed and 50 non-exposed individuals. We evaluated the frequency of micronucleus (MN), nuclear bud (NBUD), binucleated (BN) cells, and karyolitic (KL), pyknotic (PY), and karyorrhectic (KH) cells. The results showed that the MN, BN, PY, and KH frequencies of the pesticide-exposed group were significantly higher than those of the controls (P ˂ 0.05, P ˂ 0.05, P ˂ 0.01, and P ˂ 0.05, respectively). We observed that the MN, BN, PY, and KH frequencies in the autumn were statistically different compared with those in the control group (P = 0.037 for MN, P = 0.001 for BN, P = 0.016 for PY, and P = 0.033 for KH). The same comparison was done in the spring for the control, and there was a statistically significant difference for MN (P = 0.046) and PY (P = 0.014). We can conclude that pesticide exposure in greenhouse workers was one of the factors that altered DNA damages, cell death, and chromosomal instability in oral mucosa cells.

The synergistic effect of tobacco and alcohol consumption on oral squamous cell carcinoma: a systematic review and meta-analysis

OBJECTIVES

This systematic review (SR) aimed to summarise and critically appraise available evidence about the association between the synergistic consumption of alcohol and tobacco and the occurrence of oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

Observational studies investigating the association between the synergistic consumption of alcohol and tobacco and OSCC occurrence were included. Studies were selected in a two-phase process and searches were conducted on five main electronic databases, complemented by three grey literature databases.

RESULTS

From 3260 records identified, 33 articles were included for qualitative analysis, of which 15 were included in the meta-analyses. Overall, the synergistic consumption was positively associated with the occurrence of OSCC (odds ratio [OR] = 5.37; 95% confidence interval [95%CI] = 3.54-8.14). Increased odds for OSCC occurrence were observed regarding the synergistic consumption of alcohol and smoked tobacco (OR = 4.74; 95%CI = 3.51-6.40), alcohol and smokeless tobacco (OR = 7.78; 95%CI = 2.86-21.14), and alcohol, smoked tobacco, and smokeless tobacco (OR = 16.17; 95%CI = 7.97-32.79).

CONCLUSIONS

According to the results of this SR, the synergistic consumption of alcohol and tobacco (both smoked and smokeless) significantly increased the odds for the occurrence of OSCC.

CLINICAL RELEVANCE

The knowledge provided by this SR may be useful for a better understanding of differences in the effect of synergistic consumption of alcohol and tobacco products in OSCC development. These data might aid healthcare authorities to develop measures for tobacco and alcohol control considering the needs of their population.

Micronuclei in Exfoliated Cells: A Biomarker of Genotoxicity in Tobacco Users

Aims:

The aim of this study was to analyze the tobacco-related genotoxic effects in individual with habit of smoking and chewing tobacco.

Materials and Methods:

The present study sample consisted of 120 individuals attending the outpatient department of D. J. College of Dental Sciences and Research, Modinagar, Uttar Pradesh (UP). The sample was divided into four groups as follows: Group I (individuals with habit of smoking tobacco), Group II (individuals with habit of chewing tobacco), Group III (individuals with habit of smoking and chewing tobacco), and Group IV control group (nontobacco-exposed individuals). Patients were asked to rinse their mouth gently with water. The exfoliated cells were obtained by scraping the buccal mucosa of individuals with a wooden spatula. The scraped cells were placed on the precleaned slides. The smears were then stained with RAPID-PAP™ and analyzed under the microscope. Data were analyzed using SPSS statistical software.

Results:

In the present study, an arbitrary unit was obtained using frequency/day multiplied by the duration of years (risk multiplication factor [RMF], a positive and significant correlation were observed between the RMF and the mean percentage of micronucleated cell count in smokers, chewers, and in individuals with both smoking and chewing habit, respectively. A weak positive and nonsignificant correlation were observed between age and mean percentage of micronucleated cells in smokers and smokers + chewers, respectively, while it was weak negative and nonsignificant in chewers. In control group, correlation between age and percentage of micronucleated cells was weak positive and nonsignificant at 5% level of significance.

Conclusion:

The micronuclei in exfoliated mucosal cells from buccal mucosa can be used as a biomarker of genotoxicity in predicting the effects of carcinogens.

DNA damage in oral epithelial cells of individuals chronically exposed to indoor radon (222Rn) in a hydrothermal area

Hydrothermal areas are potentially hazardous to humans as volcanic gases such as radon (²²²Rn) are continuously released from soil diffuse degassing. Exposure to radon is estimated to be the second leading cause of lung cancer, but little is known about radon health-associated risks in hydrothermal regions. This cross-sectional study was designed to evaluate the DNA damage in the buccal epithelial cells of individuals chronically exposed to indoor radon in a volcanic area (Furnas volcano, Azores, Portugal) with a hydrothermal system. Buccal epithelial cells were collected from 33 individuals inhabiting the hydrothermal area (Ribeira Quente village) and from 49 individuals inhabiting a non-hydrothermal area (Ponta Delgada city). Indoor radon was measured with Ramon 2.2 detectors. Chromosome damage was measured by micronucleus cytome assay, and RAPD-PCR was used as a complementary tool to evaluate DNA damage, using three 10-mer primers (D11, F1 and F12). Indoor radon concentration correlated positively with the frequency of micronucleated cells (r _s = 0.325, p = 0.003). Exposure to radon is a risk factor for the occurrence micronucleated cells in the inhabitants of the hydrothermal area (RR = 1.71; 95% CI, 1.2-2.4; p = 0.003). One RAPD-PCR primer (F12) produced differences in the banding pattern, a fact that can indicate its potential for detecting radon-induced specific genomic alterations. The observed association between chronic exposure to indoor radon and the occurrence of chromosome damage in human oral epithelial cells evidences the usefulness of biological surveillance to assess mutations involved in pre-carcinogenesis in hydrothermal areas, reinforcing the need for further studies with human populations living in these areas.

Impact of crack cocaine use on the occurrence of oral lesions and micronuclei

The aim of this study was to investigate the occurrence of oral lesions and micronuclei in crack cocaine users. A cross-sectional study was conducted involving 106 crack users and 106 non-users matched for age, sex, and tobacco use. Socio-demographic characteristics, the consumption of psychoactive substances, and the occurrence of fundamental lesions were investigated. Cellular changes in the oral mucosa (karyolysis, karyorrhexis, 'broken egg' events, and micronuclei) were determined by exfoliative cytology for 54 participants in each group. Crack users had a greater occurrence of fundamental lesions (P=0.001). Furthermore, they had higher mean occurrences of micronuclei (17.25 vs. 3.80), karyolysis (12.39 vs. 9.46), and karyorrhexis (30.39 vs. 10.11) (number per 1000 cells) than non-users (all P<0.05). No difference between the groups was found with regard to broken egg events (P>0.05). After controlling for confounding variables, fundamental lesions were 2.02-fold more frequent and micronuclei were 3.54-fold more frequent in crack users. Crack use was found to be associated with clinical and cellular changes in the oral mucosa. These findings can contribute to the planning of health care for individuals who are dependent on street drugs.

The micronucleus test for the oral mucosa: global trends and new questions

This study reviews global trends in the publication of papers on the micronucleus test of the exfoliated cells of the oral mucosa in mammals as an approach for environmental biomonitoring. This test has been widely used due to its precision for the detection of chromosome damage. Our temporal analysis showed a significant increase (p < 0.05) in the publication of papers on the oral mucosa over the past 33 years. Brazil was the country that published most papers (24% of the total), followed by India (16%), the USA (10%), Mexico (7%), and Turkey (6%). A further 30 countries contributed the other 37% of the papers. Overall, 99% of the micronucleus studies involved human subjects, and only 1% involved other mammals. As many wild mammals are subject to the same environmental pressures as humans, in particular chemical pollution, it seems likely that many species are equally susceptible to genotoxicogical damage. We emphasize the importance of applying this technique to the analysis of the oral mucosa of wild mammals, as well as the evaluation of its effectiveness, as observed in humans, and the expansion of the available approaches to the monitoring of environmental quality.

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.

Can Feulgen Stain be a Reliable Biomarker over PAP Stain for Estimation of Micronuclei Score?

INTRODUCTION

Malignant transformation of the Potentially Malignant Lesions (PML) in the oral cavity is associated with elevated mortality rate because of its aggressive and exceedingly invasive nature. Meticulous diagnosis and prompt therapy of PML may help prevent malignant conversion in oral lesions. Carcinogenic insult to oral cells results in chromosomal damage and formation of Micronuclei (Mn), before the development of clinical symptoms.

AIM

To determine the genotoxic effect of smoking and chewing tobacco on target tissue using Mn assay and to evaluate the prevalence of other nuclear anomalies associated with it and to determine the reliability of feulgen stain for Mn assay over Papaincolau (PAP) stain.

MATERIALS AND METHODS

PAP and feulgen staining was done to study Mn in individuals who were having tobacco habits (smoking and chewing) without lesion (n=30), individuals who were having tobacco habit (smoking and chewing) with PML (n=30) and apparently healthy subjects (n=30). Data was analysed for statistical significance using SPSS 17.0 by Kruskal - Wallis Test and Bonferronii test.

RESULTS

Tobacco habits in the form of smoking and chewing have mutagenic effects on human chromosomes which is indicated by increased frequency of Mn in oral exfoliative cells. The mean Mn frequency using feulgen stain was found to be 12.27 with lesion, 10.23 with without lesion and 3.87 in controls. Whereas, metanucleated analysis revealed no significant correlation with the formation of Mn. Non-specific DNA stain (PAP) showed high numbers of Mn cells in all the groups compared to feulgen. Statistically significant difference (p<0.0001) was observed when both the stains were compared for Mn numbers.

CONCLUSION

These findings indicate that the individuals having tobacco habits (smoking and chewing) with lesion have high number of Mn cells, thus supporting the assay to be used as a reliable biomarker to assess the genotoxic effect of tobacco in the oral mucosa. The reason for almost twice as high Mn in PAP stained smears is suggestive of cell injury which is collimated by formation of keratin bodies, resulting in its misinterpretation as Mn, leading to false positive results. Hence, it was concluded that PAP stain can be used to identify abnormal cytological changes resulting from mutagenic agent but not to interpret Mn.

Clinical Evaluation of Genotoxicity of In-office Bleaching

Objective: The aim of this study was to evaluate the genotoxicity of in-office bleaching with 35% hydrogen peroxide in epithelial cells from the gingival and lip tissues.

Methods and Materials: Thirty volunteers with central incisors shade A1 or darker were selected for this study. The gingival tissue of the teeth to be bleached was isolated with a light-polymerized resin dam, and the 35% hydrogen peroxide gel was administered during three 15-minute applications over the course of the 45-minute application period. Two bleaching sessions with a one-week interval in between were performed. Exfoliated oral mucosa gingival epithelial cells and upper lip lining were collected at baseline and one month after the in-office dental bleaching. The scraped cells were placed on clean glass slides and smears were prepared. After staining with Giemsa solution, two blinded examiners performed cell and micronuclei counts under a 100× optical microscope. Tooth sensitivity was evaluated using the Visual Analogue Scale (VAS). Shade evaluation was recorded before and one month after the bleaching treatment with the value-oriented shade guide Vita Bleachedguide 3D-MASTER and the spectrophotometer Vita Easyshade. Data from the shade guide units and the micronuclei (MN) frequency were subjected to a Mann-Whitney test (α=0.05). The overall difference between before and one month after the bleaching treatment (ΔE and ΔSGU), absolute risk, and intensity of tooth sensitivity (TS) were calculated, as was the 95% confidence interval (CI).

Results: The frequency of MN was not increased after bleaching with 35% hydrogen peroxide in both study groups (p&gt;0.05). The absolute risk of TS of the participants was 93% (95% CI, 79%-98%), with a mean VAS intensity of 5.7 ± 2.9 (95% CI, 4.6-6.8). Meaningful whitening was observed after bleaching. The change in shade guide units in the Bleachedguide 3D-MASTER was 2.3 ± 1.4. In terms of ΔE, the change in color was 7.7 ± 3.5.

Conclusions: The in-office bleaching did not induce DNA damage to the gingival and lip tissue during the bleaching period. Although effective whitening was observed, most of the participants experienced TS.

Cytogenetic Biomonitoring in Buccal Mucosa Cells from Young Smokers

OBJECTIVE

Nowadays, much attention has been focused on the search for new non-invasive methodologies able to predict malignant transformation of oral mucosa cells. The aim of the present study was to comparatively evaluate DNA damage (micronucleus) and cellular death (pyknosis, karyolysis and karyorrhexis) in exfoliated oral mucosa cells from smokers and non-smokers in buccal mucosa cells.

STUDY DESIGN

A total of 24 young, healthy smokers and 14 non-smokers were included in this setting. Individuals had epithelial cells from the cheek mechanically exfoliated, placed in fixative and dropped in clean slides which were checked for the above nuclear phenotypes.

RESULTS

Smokers presented more (p < 0.05) micronucleated oral mucosa cells than non-smokers. Tobacco smoke was not able to increase other nuclear alterations closely related to cytotoxicity such as karyorrhexis, pyknosis and karyolysis.

CONCLUSION

In summary, these data indicate that the cigarette is able to induce micronuclei in oral mucosa cells, so the micronucleus test is a suitable method for predicting oral cancer risk.

Comparative evaluation of the mutagenicity and genotoxicity of smoke condensate derived from Korean cigarettes

OBJECTIVES

Cigarette smoking is associated with carcinogenesis owing to the mutagenic and genotoxic effects of cigarette smoke. The aim of this study was to evaluate the mutagenic and genotoxic effects of Korean cigarettes using in vitro assays.

METHODS

We selected 2 types of cigarettes (TL and TW) as benchmark Korean cigarettes for this study, because they represent the greatest level of nicotine and tar contents among Korean cigarettes. Mutagenic potency was expressed as the number of revertants per μg of cigarette smoke condensate (CSC) total particulate matter whereas genotoxic potency was expressed as a concentration-dependent induction factor. The CSC was prepared by the International Organization for Standardization 3308 smoking method. CHO-K1 cells were used in vitro micronucleus (MNvit) and comet assays. Two strains of Salmonella typhimurium (Salmonella enterica subsp.enterica; TA98 and TA1537) were employed in Ames tests.

RESULTS

All CSCs showed mutagenicity in the TA98 and TA1537 strains. In addition, DNA damage and micronuclei formation were observed in the comet and MNvit assays owing to CSC exposure. The CSC from the 3R4F Kentucky reference (3R4F) cigarette produced the most severe mutagenic and genotoxic potencies, followed by the CSC from the TL cigarette, whereas the CSC from the TW cigarette produced the least severe mutagenic and genotoxic potencies.

CONCLUSIONS

The results of this study suggest that the mutagenic and genotoxic potencies of the TL and TW cigarettes were weaker than those of the 3R4F cigarette. Further study on standardized concepts of toxic equivalents for cigarettes needs to be conducted for more extensive use of in vitro tests.

New models for prediction of micronuclei formation in nuclear medicine department workers

Background

Ionizing radiation causes detrimental health effects such as cancer and genetic damage. The study aim was to determine predictors for micronuclei (MN) occurrence and frequency in peripheral blood lymphocytes of health workers professionally exposed to radiation.

Methods

Health workers, age matched, selected for the study on regular check-ups, were divided according to the radiation exposure. The exposed group involved nuclear medicine department employees (54) and the control group comprised workers from other departments (36). Data about workers characteristics and habits, received annual doses (AD), total years of service (TYS) and exposed years of service (EYS) were taken from each subject. Blood samples were taken and micronuclei (MN) number in peripheral blood lymphocytes was calculated using CBMN assay according to standard protocols.

Results

Most workers were female, technicians, with mean age of 45.67 years and EYS about 15 years. Health workers exposed to radiation had significantly more MN than controls (p = 0.001). Female gender, older age, higher received annual doses, longer EYS and TYS increased the MN number. Technicians and laboratory workers have higher risk for MN occurrence. Significant predictors of MN formation according to constructed model were workers age, sex, AD and EYS. One EYS year increases MN frequency 1.017 times, while receiving 0.1 mSy raises MN frequency by 26 %. EYS accurately predicts 86.30 % of MN frequencies and AD 64.60 %.

Conclusions

The model, developed for the first time in this study, showed that received annual doses and duration of exposure to radiation can be used for prediction of MN numbers.

Evaluation of genotoxicity in workers exposed to low levels of formaldehyde in a furniture manufacturing facility

Formaldehyde (FA) is a chemical widely used in the furniture industry and has been classified as a potential human carcinogen. The purpose of this study was to evaluate the occupational exposure of workers to FA at a furniture manufacturing facility and the relationship between environmental concentrations of FA, formic acid concentration in urine, and DNA damage. The sample consisted of 46 workers exposed to FA and a control group of 45 individuals with no history of occupational exposure. Environmental concentrations of FA were determined by high-performance liquid chromatography. Urinary formic acid concentrations were determined by gas chromatography with flame ionization detector. DNA damage was evaluated by the micronucleus (MN) test performed in exfoliated buccal cells and comet assay with venous blood. The 8-h time-weighted average of FA environmental concentration ranged from 0.03 ppm to 0.09 ppm at the plant, and the control group was exposed to a mean concentration of 0.012 ppm. Workers exposed to higher environmental FA concentrations had urinary formic acid concentrations significantly different from those of controls (31.85 mg L(-1) vs. 19.35 mg L(-), p ≤ 0.01 Mann-Whitney test). Significant differences were found between control and exposed groups for the following parameters: damage frequency and damage index in the comet assay, frequency of binucleated cells in the MN test, and formic acid concentration in urine. The frequency of micronuclei, nuclear buds, and karyorrhexis did not differ between groups. There was a positive correlation between environmental concentrations of FA and damage frequency (Spearman's rank correlation coefficient [r s] = 0.24), damage index (r s = 0.21), binucleated cells (r s = 0.34), and urinary formic acid concentration (r s = 0.63). The results indicate that, although workers in the furniture manufacturing facility were exposed to low environmental levels of FA, this agent contributes to the observed increase in cytogenetic damage. In addition, urinary formic acid concentrations correlated strongly with occupational exposure to FA.

Evaluation of Genotoxicity and Efficacy of At-home Bleaching in Smokers: A Single-blind Controlled Clinical Trial

Objective

This single-blind controlled study evaluated the genotoxicity and efficacy of at-home bleaching in smokers and nonsmokers.

Methods

We selected 60 patients with central incisors A2 or darker: 30 smokers (experimental group) and 30 nonsmokers (control group). The bleaching was carried out with 10% carbamide peroxide for three hours a day for three weeks. The color was evaluated using a shade guide, Vita Bleachedguide 3D-Master, at baseline, during bleaching (first, second, and third weeks), and one week and one month after bleaching. Smears were obtained with a moistened wooden spatula from marginal gingiva. All the cytologic smears were stained with Giemsa solution. From each slide, 1000 cells were examined under 40× magnification and where micronuclei (MN) were located, they were examined under 100× magnification. The change in shade guide units at the different assessment periods and the frequency of MN were subjected to a two-way repeated measures analysis of variance and Tukey test (α=0.05).

Results

In both groups we detected a whitening of approximately 4 to 5 shade guide units, without color rebound after one month (p&gt;0.05). The frequency of MN was significantly higher in the experimental group than in the control group, regardless of the bleaching treatment (p&gt;0.001).

Conclusion

The efficacy of bleaching does not appear to be affected by the smoking habit. Additionally, at-home bleaching did not induce DNA damage to the gingival tissue during the bleaching period.

Cytogenetic damage in the oral mucosa cells of bladder cancer patients exposed to tobacco in Southern Tunisia

Bladder cancer was associated to exposure to several pollutants which can be absorbed, inhaled, or possibly ingested. We analyzed the frequency of micronuclei (MNC) and binucleated cells (BNC) in exfoliated cells of the oral mucosa of 24 bladder cancer (BC) patients and 48 controls residing in Southern Tunisia. An assessment was carried out on the incidence of MNC and BNC in 1,000 cells per individual. The data were analyzed with SPSS, using the chi-square and the Mann-Whitney U test, α = 0.05. The frequency of MN cells in BC cases was 2.5-fold higher, than in the control group (P < 0.001), while the difference for BNC between both groups was not significant. The smoking habits, age, and gender significantly influenced the MN but not the BNC alterations. The results of our study showed significantly increased frequencies of MN but not of BNC in exfoliated oral cells of BC patients associated with the smoking status, sex, and age. This study provides preliminary evidence that the frequency of MN in oral mucosa could be a predictive biomarker for cancers in parts of the body other than the upper aerodigestive tract, such as BC. Further scrupulous investigations are certainly warranted in order to implement this assay as a routine test in the planning and validation of cancer surveillance and prevention programs.

Evidence of genotoxicity in lymphocytes of non-smoking alcoholics

Alcohol abuse is a significant public health issue. Epidemiological studies conducted on different populations consistently showed that consumption of alcoholic beverages is associated with cytogenetic damages and higher risk for several types of cancer. However, the interpretation of many cytogenetic studies resulted complicated because some confounding factors, such as smoking habit, are not always taken into account. In the present study, the frequency of sister chromatid exchanges (SCEs), chromosome aberrations (CAs) and micronuclei (MNs) in cultured human lymphocytes was assessed on 15 alcoholic and 15 non-alcoholic control male subjects. Moreover, considering the implication of the Glutathione S-transferases gene polymorphisms in the genetic susceptibility to alcoholic liver diseases, we considered an important issue to evaluate the relationship between these gene polymorphisms and the cytogenetic damage. In our sample we exclusively considered individuals that did not smoke nor consume drugs for a period of at least 2 years prior to the analysis. Statistically significant differences were found between alcoholics and controls in the frequency of SCEs/cell (P = 0.001), RI value (P = 0.001), CAs (P = 0.002) and CAB (P = 0.002). Vice versa, no significant differences were found between alcoholics and controls in terms of MNs frequency and CBPI value. In both samples, no statistically significant association was found between the analysed GSTs gene polymorphisms and the frequencies of MNs, SCEs and CAs. Finally, among alcoholics we found a positive correlation between SCEs and CAs frequencies and the duration of alcohol abuse.

Cytogenetic abnormality in exfoliated cells of buccal mucosa in head and neck cancer patients in the Tunisian population: impact of different exposure sources

Chromosome/DNA instability could be one of the primary causes of malignant cell transformation. The objective of the present study was to evaluate the spontaneous genetic damages in exfoliated cells of buccal mucosa of head and neck cancer (HNC) by counting micronucleus (MN) and binucleated (BN) cells frequencies. MN and BN frequencies were significantly increased in HNC patients compared with controls (5.53 ± 3.09/1000 cells, 5.63 ± 2.99/1000 cells versus 2.36 ± 2.11/1000 cells, 3.09 ± 1.82/1000 cells, P < 0.001). Regarding the gender and the age, the frequencies of the MN and BN were significantly higher than those of controls (P < 0.01). The evaluation of the MN and BN frequencies revealed a significant increase (P < 0.001) in the cases in relation to the control group after controlling the risk factors (tobacco smoking and chewing and occupational exposure) of HNC. Moreover, MN and BN frequencies were significantly increased in smokers and chewers compared with nonsmokers and nonchewers among patients (P < 0.05). MN frequency was significantly (P = 0.014) different between patients occupationally exposed (6.99 ± 3.40/1000 cells) and nonexposed (4.70 ± 2.48/1000 cells) among HNC group. The logistic regression model illustrated that HNC was significantly associated with frequencies of MN (OR = 8.63, P < 0.0001) and BN (OR = 5.62, P = 0.001). Our results suggest that increased chromosome/DNA instabilities may be associated with HNC.