Low fruit consumption and folate deficiency are associated with LINE-1 hypomethylation in women of a cancer-free population

Environmental Influences on the Epigenome: Exposure- Associated DNA Methylation in Human Populations

DNA methylation is the most well studied of the epigenetic regulators in relation to environmental exposures. To date, numerous studies have detailed the manner by which DNA methylation is influenced by the environment, resulting in altered global and gene-specific DNA methylation. These studies have focused on prenatal, early-life, and adult exposure scenarios. The present review summarizes currently available literature that demonstrates a relationship between DNA methylation and environmental exposures. It includes studies on aflatoxin B₁, air pollution, arsenic, bisphenol A, cadmium, chromium, lead, mercury, polycyclic aromatic hydrocarbons, persistent organic pollutants, tobacco smoke, and nutritional factors. It also addresses gaps in the literature and future directions for research. These gaps include studies of mixtures, sexual dimorphisms with respect to environmentally associated methylation changes, tissue specificity, and temporal stability of the methylation marks.

LINE-1 hypermethylation in white blood cell DNA is associated with high-grade cervical intraepithelial neoplasia

Background

Long Interspersed Nuclear Elements-1 (LINEs-1) methylation from white blood cells (WBCs) DNA has been proposed as biomarker associated with different types of cancer. The aim of the present study was to investigate the degree of WBCs LINE-1 methylation, according to high-risk Human Papilloma Virus (hrHPV) status in a healthy population, and the association with high-grade Cervical Intraepithelial Neoplasia (CIN2+) in hrHPV positive women.

Methods

Women with abnormal cervical cells were enrolled and classified by histological diagnosis and hrHPV infection. A structured questionnaire was used to obtain information on socio-demographic variables and lifestyle factors. LINE-1 methylation level in WBCs was measured by pyrosequencing-based methylation analysis after bisulfite conversion.

Results

Among 252 women diagnosed with normal cervical epithelium, with regard to LINE-1 methylation level no significant difference was observed between hrHPV positive and hrHPV negative women, also adjusting for known risk factors of infection. The association between WBCs LINE-1 methylation and CIN2+ status was analyzed in hrHPV positive women. The median value of LINE-1 methylation levels was higher in cases (CIN2+) than in controls (75.00% versus 73.17%; p = 0.002). For a one-unit increase in LINE-1 methylation level, the odds of being diagnosed with CIN2+ increased by 10%, adjusting for known factors related to LINE-1 methylation (adjOR: 1.10; 95% CI:1.01–1.20; p = 0.032). The Receiver-Operating Characteristic (ROC) curve analysis identified the cut-off value of 73.8% as the best threshold to separate cases from controls (sensitivity: 63.4% and specificity: 61.8%).

Conclusions

LINE-1 methylation status in WBCs DNA may represent a cost-effective and tissue-accessible biomarker for high-grade CIN in hrHPV positive women. However, LINE-1 hypermethylation cannot be considered specific for cervical cancer (CC) and a model based solely on LINE-1 methylation levels has limited performance. Further investigations are necessary to propose and validate a novel methylation biomarker panel, based on LINE-1 methylation and other differentially methylated regions, for the screening of women at risk of CC.

Guide for Current Nutrigenetic, Nutrigenomic, and Nutriepigenetic Approaches for Precision Nutrition Involving the Prevention and Management of Chronic Diseases Associated with Obesity

Chronic diseases, including obesity, are major causes of morbidity and mortality in most countries. The adverse impacts of obesity and associated comorbidities on health remain a major concern due to the lack of effective interventions for prevention and management. Precision nutrition is an emerging therapeutic approach that takes into account an individual's genetic and epigenetic information, as well as age, gender, or particular physiopathological status. Advances in genomic sciences are contributing to a better understanding of the role of genetic variants and epigenetic signatures as well as gene expression patterns in the development of diverse chronic conditions, and how they may modify therapeutic responses. This knowledge has led to the search for genetic and epigenetic biomarkers to predict the risk of developing chronic diseases and personalizing their prevention and treatment. Additionally, original nutritional interventions based on nutrients and bioactive dietary compounds that can modify epigenetic marks and gene expression have been implemented. Although caution must be exercised, these scientific insights are paving the way for the design of innovative strategies for the control of chronic diseases accompanying obesity. This document provides a number of examples of the huge potential of understanding nutrigenetic, nutrigenomic, and nutriepigenetic roles in precision nutrition.

Global Level of Plasma DNA Methylation is Associated with Overall Survival in Patients with Hepatocellular Carcinoma

BACKGROUND

The impact of folate deficiency on global DNA methylation is uncertain. It also is unclear whether global DNA methylation is associated with outcome in HCC. LINE-1 methylation levels, as a surrogate marker of global methylation, may be influenced by folate deficiency. However, the interaction between LINE-1 methylation and folate level on overall survival (OS) in hepatocellular carcinoma (HCC) patients is unknown. We evaluated whether LINE-1 hypomethylation and folate deficiency are associated with HCC prognosis.

METHODS

We prospectively recruited 172 HCC patients between 2008 and 2012. LINE-1 methylation levels in plasma and white blood cells (WBC) were measured by pyrosequencing, and plasma folate levels by a radioprotein-binding assay.

RESULTS

Patients with plasma LINE-1 methylation <70.0% (hypomethylation) had significantly worse OS compared with those with ≥70.0% methylation (hypermethylation) [hazard ratio (HR) = 1.77; 95% confidence interval (CI) 1.12-2.79; P = 0.015]. HCC patients with lower plasma folate levels also had worse survival (<27.7 vs. ≥27.7 nmol/L; HR = 1.96; 95% CI, 1.24-3.09; P = 0.004). Furthermore, survival was poor in patients in whom both plasma LINE-1 methylation and folate levels were low compared with those patients in whom both levels were high (HR = 3.36; 95%CI, 1.77-6.40; P < 0.001). This interaction neared statistical significance (P = 0.057). No significant association was found between WBC LINE-1 methylation levels and survival.

CONCLUSIONS

These findings suggest that both lower plasma levels of LINE-1 methylation and folate are associated with worse survival in HCC patients.

Low maternal adherence to a Mediterranean diet is associated with increase in methylation at the MEG3-IG differentially methylated region in female infants

Diet is dictated by the surrounding environment, as food access and availability may change depending on where one lives. Maternal diet during pregnancy is an important part of the in utero environment, and may affect the epigenome. Studies looking at overall diet pattern in relation to DNA methylation have been lacking. The Mediterranean diet is known for its health benefits, including decreased inflammation, weight loss, and management of chronic diseases. This study assesses the association between maternal adherence to a Mediterranean diet pattern during pregnancy and infant DNA methylation at birth. Mediterranean diet adherence in early pregnancy was measured in 390 women enrolled in the Newborn Epigenetic Study, and DNA methylation was assessed in their infants at birth. Multinomial logistic regression was used to assess the association between adherence to a Mediterranean diet and infant methylation at the MEG3, MEG3-IG, pleiomorphic adenoma gene-like 1, insulin-like growth factor 2 gene, H19, mesoderm-specific transcript, neuronatin, paternally expressed gene 3, sarcoglycan and paternally expressed gene 10 regions, measured by pyrosequencing. Infants of mothers with a low adherence to a Mediterranean diet had a greater odds of hypo-methylation at the MEG3-IG differentially methylated region (DMR). Sex-stratified models showed that this association was present in girls only. This study provides early evidence on the association between overall diet pattern and methylation at the 9 DMRs included in this study, and suggests that maternal diet can have a sex-specific impact on infant DNA methylation at specific imprinted DMRs.

Relationships between Global DNA Methylation in Circulating White Blood Cells and Breast Cancer Risk Factors

It is not yet clear whether white blood cell DNA global methylation is associated with breast cancer risk. In this review we examine the relationships between multiple breast cancer risk factors and three markers of global DNA methylation: LINE-1, 5-mdC, and Alu. A literature search was conducted using Pubmed up to April 1, 2016, using combinations of relevant outcomes such as “WBC methylation,” “blood methylation,” “blood LINE-1 methylation,” and a comprehensive list of known and suspected breast cancer risk factors. Overall, the vast majority of reports in the literature have focused on LINE-1. There was reasonably consistent evidence across the studies examined that males have higher levels of LINE-1 methylation in WBC DNA than females. None of the other demographic, lifestyle, dietary, or health condition risk factors were consistently associated with LINE-1 DNA methylation across studies. With the possible exception of sex, there was also little evidence that the wide range of breast cancer risk factors we examined were associated with either of the other two global DNA methylation markers: 5-mdC and Alu. One possible implication of the observed lack of association between global WBC DNA methylation and known breast cancer risk factors is that the association between global WBC DNA methylation and breast cancer, if it exists, is due to a disease effect.

Integrated approach of nutritional and molecular epidemiology, mineralogical and chemical pollutant characterisation: the protocol of a cross-sectional study in women

INTRODUCTION

Environmentally-related health and disease are the result of the exposome, the totality of a person's environmental exposures, from all sources and routes, across their lifespan. Epigenetic phenomena, including DNA methylation, can be potentially modified by environmental and lifestyle factors, and result in environmental reprogramming of the genome for exposed individuals and for future generations of offspring.

OBJECTIVE

The objective of the project is to evaluate the risk of DNA hypomethylation due to air pollution, Mediterranean diet adherence, folate intake, and demographic and socioeconomic factors, in healthy women living in the metropolitan area of Catania, Italy.

METHODS AND ANALYSIS

Non-pregnant healthy women will be enrolled in a cross-sectional study. Sociodemographic, lifestyle and dietary intake information will be collected. LINE-1 methylation will be measured by pyrosequencing. The participants' home addresses will be geocoded and each woman will be assigned to the closest monitoring station for particulate matter (PM) exposure assessment. Mineralogical-chemical characterisation of PM and cellular model assays will be performed. An integrated approach will be designed to estimate the combined possible effect of air pollution, Mediterranean diet adherence, folate intake and other lifestyle characteristics on LINE-1 methylation levels.

ETHICS AND DISSEMINATION

The project has been approved by the ethics committees of the involved institution and funded by the University of Catania (Finanziamento della Ricerca, FIR 2014). All participants will be fully informed of the purpose and procedures of the study, and signed written consents will be obtained. All the data collected will be treated confidentially and analysed in an aggregate and anonymous way. The results will be published in peer-reviewed journals and communicated to local public health agencies, in order to provide essential information for timely and effective public health action.

Advances in Integrating Traditional and Omic Biomarkers When Analyzing the Effects of the Mediterranean Diet Intervention in Cardiovascular Prevention

Intervention with Mediterranean diet (MedDiet) has provided a high level of evidence in primary prevention of cardiovascular events. Besides enhancing protection from classical risk factors, an improvement has also been described in a number of non-classical ones. Benefits have been reported on biomarkers of oxidation, inflammation, cellular adhesion, adipokine production, and pro-thrombotic state. Although the benefits of the MedDiet have been attributed to its richness in antioxidants, the mechanisms by which it exercises its beneficial effects are not well known. It is thought that the integration of omics including genomics, transcriptomics, epigenomics, and metabolomics, into studies analyzing nutrition and cardiovascular diseases will provide new clues regarding these mechanisms. However, omics integration is still in its infancy. Currently, some single-omics analyses have provided valuable data, mostly in the field of genomics. Thus, several gene-diet interactions in determining both intermediate (plasma lipids, etc.) and final cardiovascular phenotypes (stroke, myocardial infarction, etc.) have been reported. However, few studies have analyzed changes in gene expression and, moreover very few have focused on epigenomic or metabolomic biomarkers related to the MedDiet. Nevertheless, these preliminary results can help to better understand the inter-individual differences in cardiovascular risk and dietary response for further applications in personalized nutrition.