Micronuclei in Exfoliated Buccal Cells of Children Living in a Cluster Area of Salento (Southern Italy) with a High Incidence of Lung Cancer: The IMP.AIR Study

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.

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.

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.

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.

Inflammatory cytokine storms severity may be fueled by interactions of micronuclei and RNA viruses such as COVID-19 virus SARS-CoV-2. A hypothesis

In this review we bring together evidence that (i) RNA viruses are a cause of chromosomal instability and micronuclei (MN), (ii) those individuals with high levels of lymphocyte MN have a weakened immune response and are more susceptible to RNA virus infection and (iii) both RNA virus infection and MN formation can induce inflammatory cytokine production. Based on these observations we propose a hypothesis that those who harbor elevated frequencies of MN within their cells are more prone to RNA virus infection and are more likely, through combined effects of leakage of self-DNA from MN and RNA from viruses, to escalate pro-inflammatory cytokine production via the cyclic GMP-AMP synthase (cGAS), stimulator of interferon genes (STING) and the Senescence Associated Secretory Phenotype (SASP) mechanisms to an extent that is unresolvable and therefore confers high risk of causing tissue damage by an excessive and overtly toxic immune response. The corollaries from this hypothesis are (i) those with abnormally high MN frequency are more prone to infection by RNA viruses; (ii) the extent of cytokine production and pro-inflammatory response to infection by RNA viruses is enhanced and possibly exceeds threshold levels that may be unresolvable in those with elevated MN levels in affected organs; (iii) reduction of MN frequency by improving nutrition and life-style factors increases resistance to RNA virus infection and moderates inflammatory cytokine production to a level that is immunologically efficacious and survivable.

Biomonitoring of children and adolescents using orthodontic appliances made of acrylic resins through micronucleus testing of exfoliated buccal and palatal mucosa cells

INTRODUCTION

The present study aimed to investigate the occurrence of micronuclei and the degenerative nuclear alterations indicative of apoptosis and necrosis in the exfoliated buccal and palatal mucosa cells of children and adolescents using orthodontic appliances made of self-curing acrylic resins.

METHODS

The micronuclei and nuclear alterations were evaluated in a minimum of 2000 cells collected from the cheeks and palates of 30 patients of both sexes, aged between 6 and 12 years. The cell evaluations were performed before appliance installation and 15 to 21 days after installation. A conditional test was used. In all analyses, the significance level was 5%.

RESULTS

No differences in the occurrence of micronuclei or the nuclear degenerative changes indicative of apoptosis and necrosis were observed in the cheek cells between the 2 time points (P > 0.05). However, evaluation of the palate cells revealed a significant increase in the occurrence of micronuclei and the nuclear alterations indicative of apoptosis (P < 0.01) but not of karyolysis (P > 0.05).

CONCLUSIONS

Direct contact of orthodontic appliances made of acrylic resins with the oral mucosa increases the incidence of chromosomal damage and degenerative nuclear alterations.

Cytogenotoxicity Evaluation of Young Adults Exposed to High Levels of Air Pollution in a Mexican Metropolitan Zone Using Buccal Micronucleus Cytome Assay

Air pollution has become a serious public health problem globally. Recent studies support the harmful effect of air pollution on human health, in addition to scientific evidence that recognizes it as a human carcinogen. The buccal micronucleus cytome (BMC) assay is employed extensively to measure cytotoxic and genotoxic damage in a population exposed to environmental contamination. The objective of this study was to evaluate the cytotoxic and genotoxic effects in healthy young adults exposed to different levels of air pollution and to identify areas with air pollution rates above the regulatory limits. This study was performed through the BMC assay in oral mucosa samples from 80 healthy young adults from the Guadalajara metropolitan zone. Three highly contaminated areas were taken into account: Tlaquepaque, Miravalle, and Las Pintas. Las Aguilas, a less contaminated area, was used as a reference. The frequencies of nuclear abnormalities in the areas with the highest and lowest levels of air pollution were compared with the Mann–Whitney U test. In addition, an analysis of the concentration of environmental pollutants, particulate matter ≤ 10 μm (PM10), ozone (O₃), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and carbon monoxide (CO), were carried out in the mentioned areas, in order to identify the events above the regulatory limits in a year period. The results showed that young adults exposed to a higher concentration of pollutants showed higher frequencies of nuclear abnormalities. The individuals from the areas of Tlaquepaque, Miravalle, and Las Pintas showed cytotoxic damage since statistically significant differences were found in the abnormalities of pyknotic nuclei (PNs), condensed chromatin (CC), karyorrhexis (KX), and karyolysis (KL). The individuals who showed the most cytotoxic damage were from the Las Pintas area with higher frequencies in nuclear abnormalities (PNs, CC, KX, and KL) (p < 0.0001). Genotoxic damage was found in individuals from two zones, Miravalle and Las Pintas, with statistically significant differences in the abnormality of nuclear buds (NBUDs) (p < 0.0001). Our results suggest that exposure to high levels of air pollution in healthy young adults has an effect on cellular and nuclear integrity and thus in human health, since areas with higher air pollution showed an increase in cytotoxicity, specifically in early and late markers of cell death (CC, KX, PN, and KL) and genotoxic damage (BUDs).

Obesity, oxidative DNA damage and vitamin D as predictors of genomic instability in children and adolescents

BACKGROUND/OBJECTIVES

Epidemiological evidence indicates obesity in childhood and adolescence to be an independent risk factor for cancer and premature mortality in adulthood. Pathological implications from excess adiposity may begin early in life. Obesity is concurrent with a state of chronic inflammation, a well-known aetiological factor for DNA damage. In addition, obesity has been associated with micro-nutritional deficiencies. Vitamin D has attracted attention for its anti-inflammatory properties and role in genomic integrity and stability. The aim of this study was to determine a novel approach for predicting genomic instability via the combined assessment of adiposity, DNA damage, systemic inflammation, and vitamin D status.

SUBJECTS/METHODS

We carried out a cross-sectional study with 132 participants, aged 10-18, recruited from schools and paediatric obesity clinics in London. Anthropometric assessments included BMI Z-score, waist and hip circumference, and body fat percentage via bioelectrical impedance. Inflammation and vitamin D levels in saliva were assessed by enzyme-linked immunosorbent assay. Oxidative DNA damage was determined via quantification of 8-hydroxy-2'-deoxyguanosine in urine. Exfoliated cells from the oral cavity were scored for genomic instability via the buccal cytome assay.

RESULTS

As expected, comparisons between participants with obesity and normal range BMI showed significant differences in anthropometric measures (p < 0.001). Significant differences were also observed in some measures of genomic instability (p < 0.001). When examining relationships between variables for all participants, markers of adiposity positively correlated with acquired oxidative DNA damage (p < 0.01) and genomic instability (p < 0.001), and negatively correlated with vitamin D (p < 0.01). Multiple regression analyses identified obesity (p < 0.001), vitamin D (p < 0.001), and oxidative DNA damage (p < 0.05) as the three significant predictors of genomic instability.

CONCLUSIONS

Obesity, oxidative DNA damage, and vitamin D deficiency are significant predictors of genomic instability. Non-invasive biomonitoring and predictive modelling of genomic instability in young patients with obesity may contribute to the prioritisation and severity of clinical intervention measures.

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.

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.

Monitoring human genotoxicity risk associated to urban and industrial Buenos Aires air pollution exposure

The quality of life in large megacities is directly affected by its air quality. In urban environments, suspended particles from anthropogenic origin is one of the main air contaminants identified as highly genotoxic, mutagenic, or carcinogenic. Atmospheric monitoring is therefore imperative, and bioassays to detect the effects of genotoxic agents give usually excellent results. Analysis of micronucleus (MN) in exfoliated oral mucosa cells is a sensitive non-invasive method for monitoring genetic damage in human populations. The first aim of this study was to analyze and characterize levels of volatile organic compounds (VOCs), particulate matter (PM), and polycyclic aromatic hydrocarbons (PAHs) in two areas from Buenos Aires: La Plata city, an urban (U) area and Ensenada, an industrial (I) area. Secondly, we evaluated the possible health risk of its inhabitants through a simple genotoxic assay on exfoliated oral mucosa cells. Whole blood cell count and nuclear abnormalities frequencies were evaluated in the exfoliated oral mucosa cells from urban and industrial inhabitants. Smoking habit represented a significant factor increasing MN percentage while, age did not increase the production of any of the nuclear aberrations assayed (micronuclei, binucleated, karyorrhexis) when the inhabitants from the urban and the industrial areas were compared. In addition, changes in MN and binucleated cell percentages in males and females were found to be area-dependent. We suggest that regardless PM concentration, PM-specific characteristics (size, shape, chemical elements, etc.) and VOCs levels could be responsible for the different harmful genotoxic effects seen in the two areas. Although this is a preliminary study, our results allowed to recognize that individuals living in both the urban and the industrial areas could be considered susceptible groups and should periodically undergo biological monitoring and appropriate care.

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

Micronuclei (MN) are biomarkers of early biological effect often used for detecting DNA damage in human population exposed to genotoxic agents. The aim of this study was to evaluate the frequency of MN in exfoliated buccal cells of children living in an industrialized (impacted) area compared with that found in children living in a control area without significant anthropogenic impacts. A total of 462 6–8-year-old children (206 in the impacted area, 256 in the control area) attending primary school were enrolled. A questionnaire was administered to the parents of the recruited children to obtain information about personal data, lifestyles, and food habits of their children. Atmospheric particulate fractions were collected near the involved schools to assess the level of environmental exposure of the children. The presence of MN was highlighted in 68.4% of children living in the impacted area with a mean MN frequency of 0.66‰ ± 0.61‰. MN positivity and frequency were significantly lower in the control area (37.1% and 0.27‰ ± 0.43‰, respectively). The frequency of MN was positively associated with quasi-ultrafine particulate matter (PM_0.5), traffic near the home, and consuming barbecued food; while adherence to the Mediterranean diet and practicing sport were negatively associated.