Micronuclei in neonates and children: effects of environmental, genetic, demographic and disease variables

Abstract

Children may be more susceptible to the effects of the environmental exposure and medical treatments than adults; however, limited information is available about the differences in genotoxic effects in children by age, sex and health status. Micronucleus (MN) assay is a well established method of monitoring genotoxicity, and this approach is thoroughly validated for adult lymphocytes by the Human Micronucleus Biomonitoring project (HUMN.org). Similar international undertaking is in progress for exfoliated buccal cells. Most of the MN studies in children are focused on analyses of lymphocytes but in the recent years, more investigators are interested in using exfoliated cells from the oral cavity and other cell types that can be collected non-invasively, which is particularly important in paediatric cohorts. The baseline MN frequency is relatively low in newborns and its assessment requires large cohorts and cell sample counts. Available results are mostly consistent in conclusion that environmental pollutants and radiation exposures lead to the increase in the MN frequency in children. Effects of medical treatments are less clear, and more studies are needed to optimise the doses and minimise genotoxicity without compromising therapy outcomes. Despite the recent progress in MN assay in children, more studies are warranted to establish the relationship between MN in lymphocytes and exfoliated cells, to clarify sex, age and genotype differences in baseline MN levels and the changes in response to genotoxicants. One of the most important types of MN studies in children are prospective cohorts that will help to clarify the predictive value of MN and other cytome end points for cancer and other chronic diseases of childhood and adulthood. Emerging 'omic' and other novel molecular technologies may shed light on the molecular mechanisms and biological pathways associated with the MN levels in children.

Global Gene Expression Analysis in Cord Blood Reveals Gender-Specific Differences in Response to Carcinogenic Exposure In Utero

“…Micronuclei formation in peripheral blood T-lymphocytes may be regarded as a phenotypic endpoint that reflects the deleterious effects on chromosomes because of the (combined) exposure to genotoxic carcinogens (51). Previous studies report that the baseline MN frequency is relatively low in newborns and no differences in gender have been identified (29,52), which is confirmed in our study.…”

Assessment of effects of mouthwash by Buccal Micronucleus Cytome Assay: a Preliminary Study

“…In addition, these groups did not differ statistically in the MN frequencies in differentiated cells (data not shown). Bloching et al (2007) and Holland et al (2011) found a relationship between age and increased MN frequencies. These observations could be explained by cellular senescence, since the increase of MN frequencies with age occurs probably due to a combination of effects that include mutations accumulation acquired in genes involved in DNA repair, segregation of chromosomes, checkpoints cycle mobile, numerical and structural aberrations in chromosomes caused by exposure to endogenous and exogenous genotoxins (FENECH; BONASSI, 2011).…”

Assessment of the level of damage to the genetic material of children exposed to pesticides in the province of Córdoba

“…Children whose parents or relatives were smokers, consumed coffee or tea in excess, used chronic medications, have been exposed to X-rays in the past 6 months, have been exposed to contaminants in drinking water or to any other environmental pollutants close to their place of residence 28 were excluded because all these factors are considered potentially confounding for results.…”