Micronucleus Frequency in Exfoliated Buccal Cells of Children Living in an Industrialized Area of Apulia (Italy)

Is micronucleus assay in oral cells suitable biomarker for evaluating the risk of carcinogenesis in gas station attendants? A systematic review

This study aimed to evaluate all studies which used the micronucleus assay using oral cells in the attempt to understand whether such technique is efficient in evaluating genotoxicity in gas station attendants. Full manuscripts from 16 studies were carefully selected by the authors. Our results demonstrate that continuous exposure to derivatives of petroleum may lead to genotoxic effects since all studies demonstrated positive findings (16 out of 16) and 11 of them had a strong or moderate final rating. In summary, our results reveal that gas station attendants are occupationally exposed to genotoxic agents and that the micronucleus assay in oral mucosa is indeed an effective method to evaluate genotoxicity in this specific case. Such findings are very important for protecting these professionals who are continuously exposed to chemicals for long periods.

The use of micronucleus assay in oral mucosa cells as a suitable biomarker in children exposed to environmental mutagens: theoretical concepts, guidelines and future directions

In the last decades, the micronucleus assay has been recognized as a suitable biomarker for monitoring populations exposed to many different occupational factors, lifestyle, environmental conditions, radiation exposure, and deleterious effects of pesticides. The objective of this work is to direct the design of future field studies in the assessment of the risk of children exposed to environmental mutagens, radiation, and pesticides. This review sought available information on the analysis of micronuclei in oral cells in children. A literature search for papers investigating DNA damage, genetic damage, oral cells, buccal cells, genotoxicity, mutagenicity and micronucleus was begun in 2000 and is scheduled to be concluded in May, 2022. Briefly, a search of PubMed, MEDLINE, and Google Scholar for a variety of articles was performed. The results showed that there are still few studies that addressed micronuclei of oral cells in children exposed to the most diverse environmental conditions. Only environmental pollution was associated with damage to the genome of oral cells in children. Therefore, researchers need to be calibrated in cell analysis, standardization of field study protocols and the development of new research in the evaluation of children using the micronucleus test as a tool in child biomonitoring.

Is micronucleus assay in nasal mucosa cells an appropriate technique for detecting genotoxins by inhalation in humans? A systematic review

This study aimed to evaluate the scientific literature on the micronucleus assay in nasal mucosa as an appropriate method for evaluating genotoxicity caused by chemical agents. According to the PRISMA guidelines, only in vivo human studies with micronucleus assays using nasal cells were considered. Reviews, case reports, editorials, letters to the editor, and articles not written in English were excluded. The following scientific databases/search engines were used: PubMed/MEDLINE, Scopus, and Web of Science. Results: This review included 13 studies. Four articles detected no statistical significance regarding the frequency of micronuclei while nine articles showed an increase in micronuclei in nasal cells. In the qualitative analysis, two articles were considered strong, eight were moderate and three were weak. The micronucleus assay using nasal mucosa cells is a sensitive and effective technique for assessing DNA damage and an appropriate method for monitoring humans continuously exposed to chemicals.

Is micronucleus assay a suitable method for biomonitoring children exposed to X-ray? A systematic review with meta-analysis

PURPOSE

The aim of this study was to evaluate if the micronucleus test using oral epithelial cells is a suitable biomarker for biomonitoring children exposed to X-ray.

MATERIAL AND METHODS

A search was performed through the electronic databases PubMed/Medline, Scopus, and Web of Science, all studies published up to February 2022 that examined the relationship between exposure of children to radiographic examinations and micronucleus.

RESULTS

A total of 17 full-text manuscripts were screened for eligibility. Only two studies found a difference in micronucleus labeling. On the other hand, all studies showed that X-ray was able to induce cellular death in oral mucosa cells. Following the parameters of the Effective Practices in Public Health Project (EPHPP), five manuscripts reached moderate and strong scores, and four studies were categorized as weak at final rating. In the meta-analysis, statistically significant difference was detected in micronucleated cells in children before and after radiographic examinations (SMD = 0.96, 95% CI, 0.07-1.84, p = .04), with τ2=1.09; χ2=53.37, and p < .001.

CONCLUSION

Radiographic examinations in children can cause genotoxic and cytotoxic damage in the oral epithelium with a large effect size.

Electronic waste exposure and DNA damage: a systematic review and meta-analysis

OBJECTIVES

Inappropriate processing and disposal of electronic waste (e-waste) expose workers and surrounding populations to hazardous chemicals, including clastogens and aneugens. Recently, considerable literature has grown around e-waste recycling, associated chemical exposures and intermediate health outcomes, including DNA damage. Micronuclei (MN) frequency has been widely used as a biomarker to investigate DNA damage in human populations exposed to genotoxic agents. We conducted a systematic review of published studies to assess DNA damage in e-waste-exposed populations and performed a meta-analysis to evaluate the association between e-waste exposure and DNA damage.

METHODS

This systematic review with meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement checklist. Articles published in English from January 2000 through December 2020 investigating the associations between e-waste exposure and DNA damage were retrieved from the following three major databases: MEDLINE, ProQuest, and Scopus. Studies that reported the use of MN assay as a biomarker of DNA damage were included for meta-analysis. Studies that also reported other DNA damage biomarkers such as chromosomal aberrations, comet assay biomarkers, 8-hydroxy-2'-deoxyguanosine (8-OHdG), telomere length, apoptosis rate were reported using narrative synthesis.

RESULTS

A total of 20 publications were included in this review, of which seven studies were within the occupational setting, and the remaining 13 studies were ecological studies. The review found six biomarkers of DNA damage (micronuclei, comets assay parameters (tail length, % tail DNA, tail moment, and olive tail moment), 8-OHdG, telomere length, apoptosis rate and chromosomal aberrations) which were assessed using seven different biological matrices (buccal cells, blood, umbilical cord blood, placenta, urine and semen). Most studies showed elevated levels of DNA damage biomarkers among e-waste exposed populations than in control populations. The most commonly used biomarkers were micronuclei frequency (n=9) in peripheral blood lymphocytes or buccal cells and 8-OHdG (n=7) in urine. The results of the meta-analysis showed that electronic waste recycling has contributed to an increased risk of DNA damage measured using MN frequency with a pooled estimate of the standardized mean difference (SMD) of 2.30 (95% CI: 1.36, 3.24, p<0.001) based on 865 participants.

CONCLUSIONS

Taken together, evidence from this systematic review with meta-analysis suggest that occupational and non-occupational exposure to e-waste processing is associated with increased risk of DNA damage measured through MN assay and other types of DNA damage biomarkers. However, more studies from other developing countries in Africa, Latin America, and South Asia are needed to confirm and increase these results' generalizability.

Empirical relationship between chromosomal damage and airborne particulate matter: A systematic review and meta-analysis of studies in exposed populations

Ambient particulate matter (PM) has gained significant attention as an environmental risk factor for human health. Although the association between ambient PM and micronucleus (MN) induction has been investigated, the quantitative association of PM and genomic instability is inconclusive. We conducted a systematic review and meta-analysis to study the association between PM exposure and MN endpoint. Four databases were systematically searched for studies published up to November 2022, to find papers investigating the relationship between ambient PM and MN induction. Random effect models were conducted to estimate the overall effect based on the Ratio of Means (RoM) with 95% confidence intervals (95% CIs). Subgroup analysis, funnel plot, and Egger and Begg tests, were also performed. Twenty-three studies across nine countries, including 4450 participants, were included. A meta-RoM of 2.13 for MN (95% CI 1.63-2.79) was observed for individuals exposed to ambient PM compared to non-exposed. A significant difference in the subgroup test was found for buccal cells (3.16, 95% CI 2.20-4.52) and low economy level (3.61, 95% CI 1.44-9.01). Our meta-analysis suggests the presence of an association between PM exposure and the frequency of MN and identified the kind of cells and economic status as possible effect modifiers. The use of effective methods, such as the MN assay, enables identification of early genetic damage in humans, which in turn may anticipate the risk of developing respiratory diseases, including lung cancer.

A pilot biomonitoring study of air pollution in the urban area of Sarajevo, Bosnia and Herzegovina: genotoxicity assessment in buccal cells

Air pollution, recognized as a human carcinogen, is a significant cause of death in industrial and developing countries, and Bosnia and Herzegovina (B&H) is one of the leading countries for air pollution-caused death rate and has the poorest urban air quality in Europe. Despite a population decrease, urban air pollution in B&H has increased due to traffic pollution and still intensive use of solid fuel for heating and cooking. Human biomonitoring studies, regarding the described air pollution, have not been conducted before, and particularly have not been conducted in the region of Sarajevo. Good health, well-being, and environmental protection are part of the 17 defined Sustainable Development Global Goals. Accordingly, this study aimed to determine baseline levels of DNA damage in a group of Sarajevo citizens and to compare seasonal variations in DNA damage in relation to the reported levels of air pollution. From 33 individuals included in the study, samples were collected in the summer and winter seasons. The buccal micronucleus cytome (BMCyt) assay and comet assay in leucocytes isolated from saliva were performed. Mean values and standard deviations of log-transformed tail intensity (%), tail length (µm), and tail moment results in winter were 1.14 ± 0.23, 2.20 ± 0.14, and 1.03 ± 0.29, respectively, while in the summer season those values were 1.19 ± 0.19, 2.25 ± 0.17, and 1.07 ± 0.25, respectively. No significant differences were found for the comet assay parameters. Nevertheless, BMCyt results showed significant increases in micronuclei (P = .008), binuclear cells (P = .04), karyolysis (P = .0003), condensed chromatin (P = .03), and pyknosis (P = .002) in winter. Although the results of comet and BMCyt assays are not in accordance, this study contributes to the human air pollution biomonitoring in Sarajevo, B&H, and based on the genotoxic effects of air pollution evidenced by the BMCyt biomarker further studies of this kind are necessary.

Is micronucleus assay in oral exfoliated cells a useful biomarker for biomonitoring populations exposed to pesticides? A systematic review with meta-analysis

The systematic review (SR) with meta-analysis aimed to infer if micronucleus assay using oral mucosal cells a useful biomarker for biomonitoring populations continuously exposed to pesticides (EP). The SR has been made in accordance with the PRISMA-P guidelines. The PICOS strategy has focused to answer the following question: "Does exposure to pesticides cause genetic damage in oral cells?" The literature search was made in the following scientific databases: Web of Science, PubMed/Medline, and Scopus. The approach was defined as follows: standardized mean difference (SMD) and 95% confidence intervals (CI). The quality assessment of manuscripts was obtained by the EPHPP (Effective Public Health Practice Project). The GRADE tool was chosen for assessing the quality of evidence. A total of 108 articles were selected in this setting. After screening abstracts and titles, 23 manuscripts were evaluated for eligibility. After reviewing the studies, two were considered weak and 22 were classified as moderate or strong. The meta-analysis data pointed out statistically significant differences in volunteers exposed to EP (SMD = 1.23, 95% CI, 0.69 to 1.77, p < 0.001), with a Tau2 = 1.44; Chi2 = 566.38, and p < 0.001, so that the selected manuscripts were considered heterogeneous and the I2 of 97% indicated high heterogeneity. Taken together, this review was able to validate the micronucleus assay in oral exfoliated cells as a useful biomarker in individuals continuously exposed to EP because the studies categorized as moderate and strong have demonstrated positive response related to mutagenesis.

Risk Factors for Lung Cancer in the Province of Lecce: Results from the PROTOS Case–Control Study in Salento (Southern Italy)

In the province of Lecce (southern Italy), a higher incidence of lung cancer (LC) among men compared to regional and national data was reported. In a sub-area in the center of the province (cluster area), the incidence and mortality for LC was even higher. PROTOS is a case–control study aimed at investigating possible risk factors for LC in the province area. A total of 442 patients with LC and 1326 controls matched by sex and age living in the province of Lecce for at least 10 years were enrolled and georeferenced; they filled in a questionnaire with their personal information and exposures. For each risk factor, an Odds Ratio adjusted for all the other variables was calculated. The risk of LC increased with excessive use of alcohol in women, for those subjects with a family cancer history, for each increase in pack/year of cigarettes, for men more exposed considering the industrial district in the cluster area, and for those using pesticides in agriculture without wearing personal protective equipment. The higher incidence of adenocarcinoma in both sexes suggests that, in addition to cigarette smoking, concurrent exposures to other environmental, occupational, and life-style factors may play a role in increased cancer risk and should be more deeply explored.

Cytogenetic Effects in Children Exposed to Air Pollutants: A Systematic Review and Meta-Analysis

The aim of this systematic review and meta-analysis was to assess the association between exposure to ambient air pollutants and micronuclei (MN) frequency in children. This work was performed according to the Cochrane Collaboration and the PRISMA guidelines and recommendations. Articles published before November 2021 were identified by an advanced search on PubMed/MEDLINE, Scopus and Web of Science databases. A critical appraisal using a specific tool was conducted to assess the quality of each included study. All analyses were carried out by using the Review Manager (RevMan) 5.4 software (The Cochrane Collaboration, London, UK). One hundred and forty-five references were firstly identified, and, at the end of selection process, 13 studies met the inclusion criteria. Six studies carried out a direct evaluation through the use of air samplers, whereas the other ones accessed environmental databases (n = 2) or used other tools (n = 3). In two cases, exposure was not directly investigated, with children sampled in two different areas with well-known different levels of pollution. The overall effect size (ES) was 1.57 ((95% CI = 1.39; 1.78), p-value < 0.00001) (total evaluated subjects: 4162), which highlighted a statistically significant association between outdoor air pollution and MN frequency in children. As a high MN frequency has been associated with a number of pathological states and a higher risk of developing chronic degenerative diseases, our results should be taken into consideration by policy makers to design and implement interventions aimed at reducing the introduction of pollutants in the atmosphere as well as at minimizing the exposure extent, particularly in children.

The expression of microRNAs and exposure to environmental contaminants related to human health: a review

Environmental contaminants exposure may lead to detrimental changes to the microRNAs (miRNAs) expression resulting in several health effects. miRNAs, small non-coding RNAs that regulate gene expression, have multiple transcript targets and thereby regulate several signalling molecules. Even a minor alteration in the abundance of one miRNA can have deep effects on global gene expression. Altered patterns of miRNAs can be responsible for changes linked to various health outcomes, suggesting that specific miRNAs are activated in pathophysiological processes. In this review, we provide an overview of studies investigating the impact of air pollution, organic chemicals, and heavy metals on miRNA expression and the potential biologic effects on humans.Abbreviations: AHRR, aryl-hydrocarbon receptor repressor; AHR, aryl-hydrocarbon receptor; As, arsenic; BCL2, B-cell lymphoma 2; BCL2L11, B-cell lymphoma 2 like 11; BCL6, B-cell lymphoma 6; BPA, bisphenol A; CVD, cardiovascular diseases; CD40, cluster of differentiation 40; CCND1, Cyclin D1; CDKN1A, cyclin-dependent kinase inhibitor 1A; Cr, chromium; CTBP1, C-terminal binding protein 1; CXCL12, C-X-C motif chemokine ligand 12; DAZAP1, deleted in azoospermia associated protein 1; DEP, diesel exhaust particles; EGFR, epidermal growth factor receptor; eNOS, endothelial nitric oxide synthase; EVs, extracellular vesicles; FAK, focal adhesion kinase; FAS, fas cell surface death receptor; FOXO, forkhead box O; HbA1c, glycated hemoglobin; Hg, mercury; HLA-A, human leukocyte antigen A; HMGB, high-mobility group protein B; IFNAR2, interferon alpha receptor subunit 2; IL-6, interleukin-6; IRAK1, interleukin 1 receptor associated kinase 1; JAK/STAT, janus kinase/signal transducers and activators of transcription; MAPK, mitogen-activated protein kinase; miRNAs, microRNAs; MVs, microvesicles; NCDs, noncommunicable diseases; NFAT, nuclear factor of activated T cells; NFkB, nuclear factor kappa B; NRF2, nuclear factor, erythroid-derived 2; NRG3, neuregulin 3; O₃, ozone; OP, organophosphorus pesticides; PAHs, polycyclic aromatic hydrocarbons; Pb, lead; PCBs, polychlorinated biphenyls; PDCD4, programmed cell death 4; PDGFB, platelet derived growth factor subunit beta; PDGFR, platelet-derived growth factor receptor; PI3K/Akt, phosphoinositide-3-kinase/protein kinase B; PKA, protein kinase A; PM, particulate matter; PRKCQ, protein kinase C theta; PTEN, phosphatase and tensin homolog; SORT1, sortilin 1; TGFβ, transforming growth factor-β; TLR, toll-like receptor; TNF, tumor necrosis factors; TRAF1, tumor necrosis factors-receptor associated factors 1; TRAP, traffic-related air pollution; TREM1, triggering receptor expressed on myeloid cells 1; TRIAP1, TP53 regulated inhibitor of apoptosis 1; VCAM-1, vascular cell adhesion molecule 1; VEGFA, vascular endothelial growth factor A; XRCC2, X-ray repair cross complementing 2; YBX2, Y-box-binding protein 2; ZEB1, zinc finger E-box-binding homeobox 1; ZEB2, zinc finger E-box-binding homeobox 2; 8-OH-dG, 8-hydroxy-guanine.

Buccal micronucleus cytome assay in children living in an area with low anthropogenic pressure: The EFFE.BI.P. study

The study aimed to evaluate the micronucleus (MN) frequency in exfoliated buccal cells (EBCs) of 256 6-8-years-old schoolchildren living in a rural area of Salento peninsula (Southern Italy) with low anthropogenic pressure and with a normal rate of chronic diseases in order to determine the basal level of MN and identify which factors are able to influence it. Information about the personal data, lifestyles and dietary habits of the children were obtained by the administration of a questionnaire to their parents. The buccal micronucleus cytome assay was performed to evaluate the presence of early genotoxic effects among the children. In addition, the level of environmental exposure was assessed by sampling atmospheric particulate fractions near the schools attended by participants. The association between MN frequency and individual or environmental factors was also assessed. The children had a mean MN frequency of 0.27 ± 0.43‰ (95%CI = 0.22-0.33). This frequency was positively associated with vehicular traffic (OR = 2.99; 95%CI = 1.15-7.74) and negatively associated with a high educational level of the mother (OR = 0.41; 95%CI = 0.18-0.95) and physical exercise (OR = 0.56; 95%CI = 0.32-0.57). Data on genotoxic effects in buccal cells found in this study could be considered as the MN level in a pediatric population not exposed to environmental pollution.

Is micronucleus assay in oral exfoliated cells a suitable tool for biomonitoring children exposed to environmental pollutants? A systematic review

The aim of this review was to evaluate if micronucleus assay in oral exfoliated cells is a suitable tool for biomonitoring children exposed to environmental pollutants. Through the electronic databases PubMed/Medline, Scopus, and Web of Science, all published studies until April 2021 that examined the relationship between exposure to environmental pollutants and micronucleus frequency in oral cells were searched. All relevant articles using a combination of the following keywords-"children," "micronucleus," "oral cells," and "environmental pollution"-were considered. A total of 20 papers met the criteria for inclusion in the systematic review. The results regarding the cytogenetic damage induced by environmental pollutants are conflicting. Some authors have demonstrated that environmental pollution induces mutagenesis in oral cells while others did not. Following the parameters of the Project for Effective Public Health Practices (EPHPP) and after extensive reading of all the articles included, a total of 12 articles had moderate and strong scores and 8 had a classification considered weak. Taken together, this review was able to demonstrate the association between micronucleus frequency and exposure to environmental pollutants in oral exfoliated cells of children.

Early-Life Exposure to Environmental Air Pollution and Autism Spectrum Disorder: A Review of Available Evidence

The number of children diagnosed with Autism Spectrum Disorder (ASD) has rapidly increased globally. Genetic and environmental factors both contribute to the development of ASD. Several studies showed linkage between prenatal, early postnatal air pollution exposure and the risk of developing ASD. We reviewed the available literature concerning the relationship between early-life exposure to air pollutants and ASD onset in childhood. We searched on Medline and Scopus for cohort or case-control studies published in English from 1977 to 2020. A total of 20 articles were selected for the review. We found a strong association between maternal exposure to particulate matter (PM) during pregnancy or in the first years of the children’s life and the risk of the ASD. This association was found to be stronger with PM_2.5 and less evident with the other pollutants. Current evidence suggest that pregnancy is the period in which exposure to environmental pollutants seems to be most impactful concerning the onset of ASD in children. Air pollution should be considered among the emerging risk factors for ASD. Further epidemiological and toxicological studies should address molecular pathways involved in the development of ASD and determine specific cause–effect associations.

The influence of lifestyle factors on miRNA expression and signal pathways: a review

The term 'lifestyle' includes different factors that contribute to the maintenance of a good health status. Increasing evidences suggest that lifestyle factors may influence epigenetic mechanisms, such as miRNAs expression. The dysregulation of miRNAs can modify the expression of genes and molecular pathways that may lead to functional alterations. This review summarizes human studies highlighting that diet, physical activity, smoking and alcohol consumption may affect the miRNA machinery and several biological functions. Most miRNAs are involved in molecular pathways that influence inflammation, cell cycle regulation and carcinogenesis resulting in the onset or progression of pathological conditions. Investigating these interactions will be pivotal for understanding the etiology of pathologic processes, the potential new treatment strategies and for preventing diseases.

Intervention Effects of the Health Promotion Programme "Join the Healthy Boat" on Objectively Assessed Sedentary Time in Primary School Children in Germany

Sedentary behaviour (SB) in children is related to negative health consequences that can track into adulthood. The programme "Join the Healthy Boat" promotes reduced screen time and a less sedentary lifestyle in schoolchildren. This study investigated the effects of the programme on children's SB. For one year, teachers delivered the programme. A total of 231 children (7.0 ± 0.6 years) participated in the cluster-randomised study; there were 154 one year later at follow-up. Children's SB was assessed using multi-sensor accelerometery, screen time via parental questionnaire. Effects were analysed using (linear) mixed effects regression models. At baseline, children spent 211 (±89) min daily in SB, at follow-up 259 (±109) min/day with no significant difference between the intervention (IG) and control group (CG). SB was higher during weekends (p < 0.01, for CG and IG). However, at follow-up, daily screen time decreased in IG (screen time of >1 h/day: baseline: 33.3% vs. 27.4%; follow-up: 41.2% vs. 27.5%, for CG and IG, respectively). This multi-dimensional, low-threshold intervention for one year does not seem to achieve a significant reduction in children's SB, although screen time decreased in IG. Therefore, it should be considered that screen time cannot be the key contributor to SB and should not solely be used for changing children's SB. However, if screen time is targeted, interventions should promote the replacement of screen time with active alternatives.

Micronuclei, reproduction and child health

The current review looks for relationships between results from biomarker studies with micronucleus and health effects related to reproduction and children. In adults, an age related increase in MN is well known as well as associations with environmental exposures especially air pollution from traffic and smoking. Literature searches in PubMED and SCOPUS were performed with the following keywords reproduction, children, micronuclei, health effects. In total 162 studies were identified with the keyword children. Concerning children and health and children and environmental exposures, the titles and abstracts of a total of 162 publications were screened for language, inclusion of data from children and selected according to a study selection chart. 9 studies were included for children and health, and 21 studies for children and environmental exposures, with 12 in buccal cells and 9 in lymphocytes. The publications were read and included in tables if data on controls was available. MN frequencies were collected for peripheral blood lymphocytes (PBLs), reticulocytes or buccal cells (BC) and reported as Mean ± SD or Median (IQR). The Mean frequency Ratio, MRi, corresponding to the MN mean for study persons divided by MN mean for control persons was stated as reported in the publication or calculated by us from the data in the publication, where possible. Our systematic analysis revealed a number of positive associations of MN frequencies as a marker of increased health risk in relation to reproduction as well as child health. The majority of studies reported with children concerns exposures of children as well as maternal exposures and newborn health with MN as a biomarker of exposure. Exposure monitoring by MN as biomarker is also reported in studies of school children however most often not related to health effects. The MRis are found in ranges from 1 to 5.5 most studies around 2. As far as MN frequencies in children and exposure are concerned, the MRis range from 0.9 to 5.5, with a range from 1.3-4.9 for lymphocytes and from 1.5 to 2.5 in buccal cells, except for two studies with no differences found between cases and controls. Only one study is available for MRi calculation in reticulocytes with the value of 2.3. These data are supporting MN as a relevant biomarker for children health. However, the data is mostly from small studies with different protocol leaving out the possibility of metanalyses and even statistical comparisons among studies. The actual risk from elevated MNs in children waits large cohort studies with pooled datasets as performed with MN measured in adults. Introduction of buccal cells as non invasive alternative to lymphocytes is increasing and as with the lymphocytes standardised protocols are recommended to enable comparative studies and metaanalyses.