Micronuclei, reproduction and child health

Effect of maternal diet on the frequency of micronuclei in pregnant women and newborns: A protocol for systematic review and meta-analysis

BACKGROUND

The effects of diet on maternal and child genetic levels have been previously reported. Diet-associated DNA damage, such as the presence of micronuclei (MN), may be related to an increased risk of developing chronic diseases, such as cancer. Such damage is particularly concerning during pregnancy as it can affect the newborn.

AIM

This review will aim to summarize the primary evidence of the impact of diet during pregnancy on micronucleus frequency in the maternal-newborn population.

METHODS

This protocol was developed based on the Preferred Reporting Items guidelines for Systematic Reviews and Meta-analyses Protocol. The review was registered with the International Register of Prospective Systematic Reviews on February 17, 2022 (registration number: CRD42022302401). We will use PubMed, Embase, Web of Science, Scopus, Science direct, and Google databases to search for observational studies. This review will include studies that investigate the diet consumed by pregnant women and its effect on the frequency of MN in mothers and newborns without any time or language limitations. For data extraction, researchers will independently review the full text and collect information that characterizes the study and its findings. We will analyze the results by calculating the odds ratio for each type of diet evaluated, accompanied by a 95% confidence interval. We will perform a quantitative synthesis of homogeneous studies to perform a meta-analysis. Micronucleus frequency quantifies the effect and will be presented as the mean and standard deviation or median and interquartile range.

EXPECTED RESULTS

This review will aim to identify which dietary patterns during pregnancy may be associated with an increase in the frequency of MN in mothers and their newborns. Understanding the impact of diet on the frequency of MN is essential to deepen studies and to propose strategies that aim to protect the health of the public through food.

The Importance of Monitoring Non-clonal Chromosome Aberrations (NCCAs) in Cancer Research

Cytogenetic analysis has traditionally focused on the clonal chromosome aberrations, or CCAs, and considered the large number of diverse non-clonal chromosome aberrations, or NCCAs, as insignificant noise. Our decade-long karyotype evolutionary studies have unexpectedly demonstrated otherwise. Not only the baseline of NCCAs is associated with fuzzy inheritance, but the frequencies of NCCAs can also be used to reliably measure genome or chromosome instability (CIN). According to the Genome Architecture Theory, CIN is the common driver of cancer evolution that can unify diverse molecular mechanisms, and genome chaos, including chromothripsis, chromoanagenesis, and polypoidal giant nuclear and micronuclear clusters, and various sizes of chromosome fragmentations, including extrachromosomal DNA, represent some extreme forms of NCCAs that play a key role in the macroevolutionary transition. In this chapter, the rationale, definition, brief history, and current status of NCCA research in cancer are discussed in the context of two-phased cancer evolution and karyotype-coded system information. Finally, after briefly describing various types of NCCAs, we call for more research on NCCAs in future cytogenetics.

Genotoxic Risks to Male Reproductive Health from Radiofrequency Radiation

During modern era, mobile phones, televisions, microwaves, radio, and wireless devices, etc., have become an integral part of our daily lifestyle. All these technologies employ radiofrequency (RF) waves and everyone is exposed to them, since they are widespread in the environment. The increasing risk of male infertility is a growing concern to the human population. Excessive and long-term exposure to non-ionizing radiation may cause genetic health effects on the male reproductive system which could be a primitive factor to induce cancer risk. With respect to the concerned aspect, many possible RFR induced genotoxic studies have been reported; however, reports are very contradictory and showed the possible effect on humans and animals. Thus, the present review is focusing on the genomic impact of the radiofrequency electromagnetic field (RF-EMF) underlying the male infertility issue. In this review, both in vitro and in vivo studies have been incorporated explaining the role of RFR on the male reproductive system. It includes RFR induced-DNA damage, micronuclei formation, chromosomal aberrations, SCE generation, etc. In addition, attention has also been paid to the ROS generation after radiofrequency radiation exposure showing a rise in oxidative stress, base adduct formation, sperm head DNA damage, or cross-linking problems between DNA & protein.

DNA damage as indicator of the environmental vulnerability of bats in Brazil's Caatinga drylands

Brazil's Caatinga drylands is under extensive environmental deterioration, with 38% of its natural cover already lost. There is a need for a better understanding of the effects of such degradation on Caatinga's rich and singular biota. Bats form a large part of this biota, and are pointed as good bioindicators. Here, we used the micronucleus test -an easy-to-use, accessible and cost-effective in vivo approach- to detect DNA damage in cells from bats of different species and feeding habits in three protected areas in the Caatinga, comparing them with samples from an industrial sugarcane plantation. We hypothesized that environmental disturbance would reflect in DNA damage, with lower levels of damage in the less disturbed protected areas. The frequency of micronucleated cells differed significantly between sites and feeding habits (carnivores > insectivores > frugivores > nectarivores > hematophagous) but did not differ between sexes. Alarmingly, the highest levels of DNA damage were in two strictly protected areas (Seridó and Raso da Catarina Ecological Stations). Glossophaga and Anoura were the genera with more damaged cells, and had, respectively, 1.48 and 3.53 times more micronucleated cells (average of 19.33 and 22.67 cells, respectively) than individuals from the same genera from the area with least damaged cells (average of 7.80 and 5.00 cells, respectively). Our analysis is a warning call for an in-depth investigation on the effects of both genotoxic contamination and environmental stressors on bats and other species in Brazil's Caatinga, including the role that historical human-induced processes -like the intense use of agrochemicals- may have had in the region.

"Micronuclei and Disease" special issue: Aims, scope, and synthesis of outcomes

The purpose of the "Micronuclei and Disease" special issue (SI) is to: (i) Determine the level of evidence for association of micronuclei (MN), a biomarker of numerical and structural chromosomal aberrations, with risk of specific diseases in humans; (ii) Define plausible mechanisms that explain association of MN with each disease; (iii) Identify knowledge gaps and research needed to translate MN assays into clinical practice. The "MN and Disease" SI includes 14 papers. The first is a review of mechanisms of MN formation and their consequences in humans. 11 papers are systematic reviews and/or meta-analyses of the association of MN with reproduction, child health, inflammation, auto-immune disease, glycation, metabolic diseases, chronic kidney disease, cardiovascular disease, eleven common cancers, ageing and frailty. The penultimate paper focuses on effect of interventions on MN frequency in the elderly. A road map for translation of MN data into clinical practice is the topic of the final paper. The majority of reviewed studies were case-control studies in which the ratio of mean MN frequency in disease cases relative to controls, i.e. the mean ratio (MR), was calculated. The mean of these MR values, estimated by meta-analyses, for lymphocyte and buccal cell MN in non-cancer diseases were 2.3 and 3.6 respectively, and for cancers they were 1.7 and 2.6 respectively. The highest MR values were observed in studies of cancer cases in which MN were measured in the same tissue as the tumour (MR = 4.9-10.8). This special issue is an important milestone in the evidence supporting MN as a reliable genomic biomarker of developmental and degenerative disease risk. These advances, together with results from prospective cohort studies, are helping to identify diseases in which MN assays can be practically employed in the clinical setting to better identify high risk patients and to prioritise them for preventive therapy.

Roadmap for translating results from the micronucleus assay into clinical practice: From observational studies to randomized controlled trials

According to the definition delivred by the WHO, a biomarker, independently from its role that may be indicative of exposure, response or effect, is inevitably linked to a clinical outcome or to a disease. The presence of a continuum from early biological events to therapy, and prognosis is the unifying mechanism that justifies this conclusion. Traditionally, the technical and inter-individual variability of the assays, together with the long duration between early pathogenetic events and the disease, prevented clinical applications to these biomarkers. These limitations became less important with the emerging of personalized preventive medicine because of the focus on disease prediction and prevention, and the recommended use of all data concerning measurable patient's features. Several papers have been published on the best validation procedures for translating biomarkers to real life. The history of cholesterol concentration is extensively discussed as a reliable example of a biomarker that - after a long and controversial validation process - is currently used in clinical practice. The frequency of micronucleated cells is a reliable biomarker for the pathogenesis of cancer and other non-communicable diseases, and the link with clinical outcomes is substantiated by epidemiological evidence and strong mechanistic basis. Available literature concerning the use of the micronucleus assay in clinical studies is discussed, and a suitable three-levels road-map driving this biomarker towards clinical practice is presented. Under the perspective of personalized medicine, the use of the micronucleus assays can play a decisive role in addressing preventive and therapeutic strategies of chronic diseases. In many cases the MN assay is either currently used in clinical practice or classified as adequate to consider translation into practice. The roadmap to clinical validation of the micronucleus assay finds inspiration from the history of biomarkers such as cholesterol, which clearly showed that the evidence from prospective studies or RCTs is critical to achieve the required level of trust from the healthcare profession. (307 words).