DNA damage in children and adolescents with cardiovascular disease risk factors

The Associations between Intakes of One-Carbon Metabolism-Related Vitamins and Breast Density among Young Women

BACKGROUND

Folate is the primary methyl donor and B vitamins are cofactors for one-carbon metabolism that maintain DNA integrity and epigenetic signatures implicated in carcinogenesis. Breast tissue is particularly susceptible to stimuli in early life. Only limited data are available on associations of one-carbon metabolism-related vitamin intake during youth and young adulthood with breast density, a strong risk factor for breast cancer.

METHODS

Over 18 years in the DISC and DISC06 Follow-up Study, diets of 182 young women were assessed by three 24-hour recalls on five occasions at ages 8 to 18 years and once at 25 to 29 years. Multivariable-adjusted linear mixed-effects regression was used to examine associations of intakes of one-carbon metabolism-related vitamins with MRI-measured percent dense breast volume (%DBV) and absolute dense breast volume (ADBV) at ages 25 to 29 years.

RESULTS

Folate intake in youth was inversely associated with %DBV (Ptrend = 0.006) and ADBV (Ptrend = 0.02). These inverse associations were observed with intake during post-, though not premenarche. In contrast, premenarche vitamin B2 intake was positively associated with ADBV (Ptrend < 0.001). Young adult folate and vitamin B6 intakes were inversely associated with %DBV (all Ptrend ≤ 0.04), whereas vitamins B6 and B12 were inversely associated with ADBV (all Ptrend ≤ 0.04).

CONCLUSIONS

Among these DISC participants intakes of one-carbon metabolism-related vitamins were associated with breast density. Larger prospective studies among diverse populations are needed to replicate these findings.

IMPACT

Our results suggest the importance of one-carbon metabolism-related vitamin intakes early in life with development of breast density and thereby potentially breast cancer risk later in life.

DNA Damage, n-3 Long-Chain PUFA Levels and Proteomic Profile in Brazilian Children and Adolescents

Fatty acids play a significant role in maintaining cellular and DNA protection and we previously found an inverse relationship between blood levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and DNA damage. The aim of this study was to explore differences in proteomic profiles, for 117 pro-inflammatory proteins, in two previously defined groups of individuals with different DNA damage and EPA and DHA levels. Healthy children and adolescents (n = 140) aged 9 to 13 years old in an urban area of Brazil were divided by k-means cluster test into two clusters of DNA damage (tail intensity) using the comet assay (cluster 1 = 5.9% ± 1.2 and cluster 2 = 13.8% ± 3.1) in our previous study. The cluster with higher DNA damage and lower levels of DHA (6.2 ± 1.6 mg/dL; 5.4 ± 1.3 mg/dL, p = 0.003) and EPA (0.6 ± 0.2 mg/dL; 0.5 ± 0.1 mg/dL, p < 0.001) presented increased expression of the proteins CDK8-CCNC, PIK3CA-PIK3R1, KYNU, and PRKCB, which are involved in pro-inflammatory pathways. Our findings support the hypothesis that low levels of n-3 long-chain PUFA may have a less protective role against DNA damage through expression of pro-inflammatory proteins, such as CDK8-CCNC, PIK3CA-PIK3R1, KYNU, and PRKCB.

Social Stress-Induced Oxidative DNA Damage Is Related to Prospective Cardiovascular Risk

Psychosocial stress increases cardiovascular risk, which coincides with enhanced oxidative DNA damage. Increased sympathetic tone-related catecholamine release causes oxidative stress, which contributes to catecholamine-related cardiotoxicity. Therefore, we tested the hypothesis whether acute psychosocial stress induces oxidative DNA damage, its degree being related to the cardiovascular risk profile and depending on the sympathetic stress response. After assessment of the prospective cardiovascular Münster score (PROCAM) to determine the risk of acute myocardial infarction, 83 male and 12 female healthy volunteers underwent the Trier social stress test for groups (TSST-G). Heart rate variability was quantified by measuring the standard deviation (SDNN) and root mean square of successive differences (RMSSD) between normal-to-normal inter-beat intervals. Salivary α-amylase (sAA) activity was assessed as a surrogate for noradrenaline plasma concentrations. Oxidative DNA damage was determined using whole-blood single-cell gel electrophoresis ("tail moment" in the "comet assay"). A total of 33 subjects presented with a prospective risk of myocardial infarction (risk+) vs. 59 subjects without risk (risk-). The TSST-G stress significantly increased blood pressure, heart rate, and sAA in both groups, while oxidative DNA damage was only increased in the risk+ group. Immediately after the TSST-G, the "tail moment" showed significant inverse linear relations with both SDNN and RMSSD. Acute psychosocial stress may cause oxidative DNA damage, the degree of which is directly related to the individual cardiovascular risk profile and depends on the stress-induced increase in the sympathetic tone.

Comet assay and its use for evaluating oxidative DNA damage in some pathological states

The comet assay, or single-cell gel electrophoresis (SCGE), is a sensitive, rapid, relatively simple and inexpensive method for detecting DNA strand breaks in individual cells. It is used in a broad variety of applications and as a tool to investigate DNA damage and repair. The sensitivity and specificity of the assay are greatly enhanced if the DNA incubated with an enzyme, whichrecognizes a specific kind of DNA damage. This damage induced by oxidative stress plays a pivotal role in many diseases and in aging. This article is a critical review of the possible application of the comet assay in some pathological states in clinical practice. Most of the studies relate to evaluating the response of an organism to chemotherapy or radiotherapy with statistically significant evidence of DNA damage in patients. Other useful applications have been demonstrated for patients with heart or neurodegenerative diseases. Only a few studies have been published on the use of this method in critically ill patients, although its use would be appropriate. There are also other scenarios where the comet assay could prove to be very useful in the future, such as in predicting the likelihood of certain pathological conditions.

Effect of short-term hazelnut consumption on DNA damage and oxidized LDL in children and adolescents with primary hyperlipidemia: a randomized controlled trial

Children with primary hyperlipidemia are prone to develop premature atherosclerosis, possibly associated with increased oxidative stress. Nutritional therapy is the primary strategy in the treatment of hyperlipidemia and associated conditions. Dietary interventions with bioactive-rich foods, such as nuts, may contribute to the modulation of both lipid profile and the oxidative/antioxidant status. Our study aimed to assess the impact of a dietary intervention with hazelnuts on selected oxidative stress markers in children and adolescents with primary hyperlipidemia. A single-blind, 8-week, randomized, controlled, three-arm, parallel-group study was performed. Children and adolescents diagnosed with primary hyperlipidemia (n=60) received dietary guidelines and were randomized into three groups: group 1 received hazelnuts with skin (HZN+S), and group 2 hazelnuts without skin (HZN-S), at equivalent doses (15-30 g/day, based on body weight); group 3 (controls) received only dietary recommendations (no nuts). At baseline and after 8 weeks, plasma oxidized low-density lipoprotein (ox-LDL) concentrations, oxidative levels of DNA damage in PBMCs and potential correlation with changes in serum lipids were examined. A reduction of endogenous DNA damage by 18.9%±51.3% (P=.002) and 23.1%±47.9% (P=.007) was observed after HZN+S and HZN-S, respectively. Oxidatively induced DNA strand breaks decreased by 16.0%±38.2% (P=.02) following HZN+S treatment. Ox-LDL levels did not change after HZN+S intervention but positively correlated with total cholesterol and LDL cholesterol. A short-term hazelnut intervention improves cell DNA protection and resistance against oxidative stress but not ox-LDL in hyperlipidemic pediatric patients. The trial was registered at ISRCTN.com, ID no. ISRCTN12261900.

Epigenetic Regulation of Centromere Chromatin Stability by Dietary and Environmental Factors

The centromere is a genomic locus required for the segregation of the chromosomes during cell division. This chromosomal region together with pericentromeres has been found to be susceptible to damage, and thus the perturbation of the centromere could lead to the development of aneuploidic events. Metabolic abnormalities that underlie the generation of cancer include inflammation, oxidative stress, cell cycle deregulation, and numerous others. The micronucleus assay, an early clinical marker of cancer, has been shown to provide a reliable measure of genotoxic damage that may signal cancer initiation. In the current review, we will discuss the events that lead to micronucleus formation and centromeric and pericentromeric chromatin instability, as well transcripts emanating from these regions, which were previously thought to be inactive. Studies were selected in PubMed if they reported the effects of nutritional status (macro- and micronutrients) or environmental toxicant exposure on micronucleus frequency or any other chromosomal abnormality in humans, animals, or cell models. Mounting evidence from epidemiologic, environmental, and nutritional studies provides a novel perspective on the origination of aneuploidic events. Although substantial evidence exists describing the role that nutritional status and environmental toxicants have on the generation of micronuclei and other nuclear aberrations, limited information is available to describe the importance of macro- and micronutrients on centromeric and pericentromeric chromatin stability. Moving forward, studies that specifically address the direct link between nutritional status, excess, or deficiency and the epigenetic regulation of the centromere will provide much needed insight into the nutritional and environmental regulation of this chromosomal region and the initiation of aneuploidy.

Biomarkers of Nutrition for Development-Folate Review

The Biomarkers of Nutrition for Development (BOND) project is designed to provide evidence-based advice to anyone with an interest in the role of nutrition in health. Specifically, the BOND program provides state-of-the-art information and service with regard to selection, use, and interpretation of biomarkers of nutrient exposure, status, function, and effect. To accomplish this objective, expert panels are recruited to evaluate the literature and to draft comprehensive reports on the current state of the art with regard to specific nutrient biology and available biomarkers for assessing nutrients in body tissues at the individual and population level. Phase I of the BOND project includes the evaluation of biomarkers for 6 nutrients: iodine, iron, zinc, folate, vitamin A, and vitamin B-12. This review represents the second in the series of reviews and covers all relevant aspects of folate biology and biomarkers. The article is organized to provide the reader with a full appreciation of folate's history as a public health issue, its biology, and an overview of available biomarkers (serum folate, RBC folate, and plasma homocysteine concentrations) and their interpretation across a range of clinical and population-based uses. The article also includes a list of priority research needs for advancing the area of folate biomarkers related to nutritional health status and development.

DNA damage in non-communicable diseases: A clinical and epidemiological perspective

Non-communicable diseases (NCDs) are a leading cause of death and disability, representing 63% of the total death number worldwide. A characteristic phenotype of these diseases is the accelerated aging, which is the result of phenomena such as accumulated DNA damage, telomere capping loss and subcellular irreversible/nonrepaired oxidative damage. DNA damage, mostly oxidative, plays a key role in the development of most common NCDs. The present review will gather some of the most relevant knowledge concerning the presence of DNA damage in NCDs focusing on cardiovascular diseases, diabetes, chronic obstructive pulmonary disease, and neurodegenerative disorders, and discussing a selection of papers from the most informative literature. The challenge of comorbidity and the potential offered by new systems approaches for introducing these biomarkers into the clinical decision process will be discussed. Systems Medicine platforms represent the most suitable approach to personalized medicine, enabling to identify new patterns in the pathogenesis, diagnosis and prognosis of chronic diseases.

The influence of micronutrients in cell culture: a reflection on viability and genomic stability

Micronutrients, including minerals and vitamins, are indispensable to DNA metabolic pathways and thus are as important for life as macronutrients. Without the proper nutrients, genomic instability compromises homeostasis, leading to chronic diseases and certain types of cancer. Cell-culture media try to mimic the in vivo environment, providing in vitro models used to infer cells' responses to different stimuli. This review summarizes and discusses studies of cell-culture supplementation with micronutrients that can increase cell viability and genomic stability, with a particular focus on previous in vitro experiments. In these studies, the cell-culture media include certain vitamins and minerals at concentrations not equal to the physiological levels. In many common culture media, the sole source of micronutrients is fetal bovine serum (FBS), which contributes to only 5-10% of the media composition. Minimal attention has been dedicated to FBS composition, micronutrients in cell cultures as a whole, or the influence of micronutrients on the viability and genetics of cultured cells. Further studies better evaluating micronutrients' roles at a molecular level and influence on the genomic stability of cells are still needed.