Impact of obesity and overweight on DNA stability: Few facts and many hypotheses

Obesity increases DNA damage in the breast epithelium

Obesity is a modifiable risk factor for breast cancer. Yet, how obesity contributes to cancer initiation is not fully understood. The goal of this study was to determine if the body mass index (BMI) and metabolic hallmarks of obesity are related to DNA damage in normal breast tissue. In a mouse model of diet-induced obesity, weight gain was associated with elevated levels of DNA double-strand breaks in the mammary gland. We also found a positive correlation between BMI and DNA breaks in the breast epithelium of premenopausal women (but not postmenopausal women). High BMI was associated with elevated systemic and tissue-level oxidative DNA damage across the lifespan, and we propose that the breast epithelium undergoing menstruous proliferation waves is particularly prone to the generation of DNA breaks from oxidative lesions. Ancestry was an important modulator of the obesity-DNA break connection. Compared to non-Hispanic Whites, women identifying as African Americans had higher levels of DNA breaks, as well as elevated leptin and IGF-1. In 3D cultures of breast acini, both leptin and IGF-1 caused an accumulation of DNA damage. The results highlight a connection between premalignant genomic alterations in the breast epithelium and metabolic health modulated by obesity and ancestry. They call for attention on biological determinants of breast cancer risk disparities.

Integrating the metabolic and molecular circuits in diabetes, obesity and cancer: a comprehensive review

The progressive globalization of sedentary lifestyles and diets rich in lipids and processed foods has caused two major public health hazards-diabetes and obesity. The strong interlink between obesity and type 2 diabetes mellitus and their combined burden encompass them into a single term 'Diabesity'. They have also been tagged as the drivers for the onset of cancer. The clinical association between diabetes, obesity, and several types of human cancer demands an assessment of vital junctions correlating the three. This review focuses on revisiting the molecular axis linking diabetes and obesity to cancer through pathways that get imbalanced owing to metabolic upheaval. We also attempt to describe the functional disruptions of DNA repair mechanisms due to overwhelming oxidative DNA damage caused by diabesity. Genomic instability, a known cancer hallmark results when DNA repair does not work optimally, and as will be inferred from this review the obtruded metabolic homeostasis in diabetes and obesity creates a favorable microenvironment supporting metabolic reprogramming and enabling malignancies. Altered molecular and hormonal landscapes in these two morbidities provide a novel connection between metabolomics and oncogenesis. Understanding various aspects of the tumorigenic process in diabesity-induced cancers might help in the discovery of new biomarkers and prompt targeted therapeutic interventions.

Oxidative DNA Damage and Arterial Hypertension in Light of Current ESC Guidelines

A new insight into oxidative stress is based on oxidative deoxyribonucleic acid (DNA) damage. DNA is the pivotal biopolymer for life and health. Arterial hypertension (HT) is a globally common disease and a major risk factor for numerous cardiovascular (CV) conditions and non-cardiac complications, making it a significant health and socio-economic problem. The aetiology of HT is multifactorial. Oxidative stress is the main driver. Oxidative DNA damage (oxidised guanosine (8OHdG), strand breaks (SSBs, DSBs)) seems to be the crucial and initiating causal molecular mechanism leading to HT, acting through oxidative stress and the resulting consequences (inflammation, fibrosis, vascular remodelling, stiffness, thickness, and endothelial dysfunction). In light of the current European Society of Cardiology (ESC) guidelines with defined gaps in the evidence, this manuscript, for the first time, (1) summarizes evidence for oxidative DNA damage in HT and other CV risk factors, (2) incorporates them into the context of known mechanisms in HT genesis, (3) proposes the existing concept of HT genesis innovatively supplemented with oxidative DNA damage, and (4) mentions consequences such as promising new targets for the treatment of HT (DNA damage response (DDR) pathways).

Molecular regulation of DNA damage and repair in female infertility: a systematic review

DNA damage is a key factor affecting gametogenesis and embryo development. The integrity and stability of DNA are fundamental to a woman's successful conception, embryonic development, pregnancy and the production of healthy offspring. Aging, reactive oxygen species, radiation therapy, and chemotherapy often induce oocyte DNA damage, diminished ovarian reserve, and infertility in women. With the increase of infertility population, there is an increasing need to study the relationship between infertility related diseases and DNA damage and repair. Researchers have tried various methods to reduce DNA damage in oocytes and enhance their DNA repair capabilities in an attempt to protect oocytes. In this review, we summarize recent advances in the DNA damage response mechanisms in infertility diseases such as PCOS, endometriosis, diminished ovarian reserve and hydrosalpinx, which has important implications for fertility preservation.

Epigenetic and transcriptional control of adipocyte function by centenarian-associated SIRT6 N308K/A313S mutant

BACKGROUND

Obesity is a major health burden. Preadipocytes proliferate and differentiate in mature adipocytes in the adipogenic process, which could be a potential therapeutic approach for obesity. Deficiency of SIRT6, a stress-responsive protein deacetylase and mono-ADP ribosyltransferase enzyme, blocks adipogenesis. Mutants of SIRT6 (N308K/A313S) were recently linked to the in the long lifespan Ashkenazi Jews. In this study, we aimed to clarify how these new centenarian-associated SIRT6 genetic variants affect adipogenesis at the transcriptional and epigenetic level.

METHODS

We analyzed the role of SIRT6 wild-type (WT) or SIRT6 centenarian-associated mutant (N308K/A313S) overexpression in adipogenesis, by creating stably transduced preadipocyte cell lines using lentivirus on the 3T3-L1 model. Histone post-translational modifications (PTM: acetylation, methylation) and transcriptomic changes were analyzed by mass spectrometry (LC-MS/MS) and RNA-Seq, respectively, in 3T3-L1 adipocytes. In addition, the adipogenic process and related signaling pathways were investigated by bioinformatics and biochemical approaches.

RESULTS

Overexpression of centenarian-associated SIRT6 mutant increased adipogenic differentiation to a similar extent compared to the WT form. However, it triggered distinct histone PTM profiles in mature adipocytes, with significantly higher acetylation levels, and activated divergent transcriptional programs, including those dependent on signaling related to the sympathetic innervation and to PI3K pathway. 3T3-L1 mature adipocytes overexpressing SIRT6 N308K/A313S displayed increased insulin sensitivity in a neuropeptide Y (NPY)-dependent manner.

CONCLUSIONS

SIRT6 N308K/A313S overexpression in mature adipocytes ameliorated glucose sensitivity and impacted sympathetic innervation signaling. These findings highlight the importance of targeting SIRT6 enzymatic activities to regulate the co-morbidities associated with obesity.

Dulaglutide reduces oxidative DNA damage and hypermethylation in the somatic cells of mice fed a high-energy diet by restoring redox balance, inflammatory responses, and DNA repair gene expressions

Obesity is an established risk factor for numerous malignancies, although it remains uncertain whether the disease itself or weight-loss drugs are responsible for a greater predisposition to cancer. The objective of the current study was to determine the impact of dulaglutide on genetic and epigenetic DNA damage caused by obesity, which is a crucial factor in the development of cancer. Mice were administered a low-fat or high-fat diet for 12 weeks, followed by a 5-week treatment with dulaglutide. Following that, modifications of the DNA bases were examined using the comet assay. To clarify the underlying molecular mechanisms, oxidized and methylated DNA bases, changes in the redox status, levels of inflammatory cytokines, and the expression levels of some DNA repair genes were evaluated. Animals fed a high-fat diet exhibited increased body weights, elevated DNA damage, oxidation of DNA bases, and DNA hypermethylation. In addition, obese mice showed altered inflammatory responses, redox imbalances, and repair gene expressions. The findings demonstrated that dulaglutide does not exhibit genotoxicity in the investigated conditions. Following dulaglutide administration, animals fed a high-fat diet demonstrated low DNA damage, less oxidation and methylation of DNA bases, restored redox balance, and improved inflammatory responses. In addition, dulaglutide treatment restored the upregulated DNMT1, Ogg1, and p53 gene expression. Overall, dulaglutide effectively maintains DNA integrity in obese animals. It reduces oxidative DNA damage and hypermethylation by restoring redox balance, modulating inflammatory responses, and recovering altered gene expressions. These findings demonstrate dulaglutide's expediency in treating obesity and its associated complications.

DNA damage, obesity and obesity-related health complications: what are new data telling us?

PURPOSE OF REVIEW

Obesity is associated with increased DNA damage, which may in turn contribute to the development of obesity-related complications. DNA damage can also affect adipocyte biology, resulting in increased adiposity. Carefully managed weight loss programs can reverse this process. This article surveys new data that support these contentions.

RECENT FINDINGS

Whole exome sequencing analyses have identified rare variants linked to high BMI and adiposity. Two of the identified genes are linked to DNA damage and DNA repair, suggesting that DNA damage itself may play a role in the cause of obesity. It has also been recognized that obesity increases DNA damage in breast tissue of carriers of BRCA mutations and rates of tumour formation in BRCA1+ mice, indicating effect of obesity on cancer development in high-risk populations. In addition, obesity promotes cancer cell chemoresistance by decreasing fatty acid oxidation involved in cellular DNA damage response, leading to apoptotic cellular death. Obesity is also associated with a reduced capacity of oocytes to repair sperm DNA damage, leading to lower in-vitro fertilization rates in women with obesity.

SUMMARY

DNA damage and cellular responses to DNA damage can be both the result and the cause of obesity and can strongly influence the development and treatment of obesity-associated diseases.

Glyphosate Use and Mosaic Loss of Chromosome Y among Male Farmers in the Agricultural Health Study

BACKGROUND

Glyphosate is the most commonly used herbicide worldwide and has been implicated in the development of certain hematologic cancers. Although mechanistic studies in human cells and animals support the genotoxic effects of glyphosate, evidence in human populations is scarce.

OBJECTIVES

We evaluated the association between lifetime occupational glyphosate use and mosaic loss of chromosome Y (mLOY) as a marker of genotoxicity among male farmers.

METHODS

We analyzed blood-derived DNA from 1,606 farmers ≥ 50 years of age in the Biomarkers of Exposure and Effect in Agriculture study, a subcohort of the Agricultural Health Study. mLOY was detected using genotyping array intensity data in the pseudoautosomal region of the sex chromosomes. Cumulative lifetime glyphosate use was assessed using self-reported pesticide exposure histories. Using multivariable logistic regression, we estimated odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between glyphosate use and any detectable mLOY (overall mLOY) or mLOY affecting ≥ 10 % of cells (expanded mLOY).

RESULTS

Overall, mLOY was detected in 21.4% of farmers, and 9.8% of all farmers had expanded mLOY. Increasing total lifetime days of glyphosate use was associated with expanded mLOY [highest vs. lowest quartile; OR = 1.75 (95% CI: 1.00, 3.07), p trend = 0.03 ] but not with overall mLOY; the associations with expanded mLOY were most apparent among older (≥ 70 years of age) men [OR = 2.30 (95% CI: 1.13, 4.67), p trend = 0.01 ], never smokers [OR = 2.32 (95% CI: 1.04, 5.21), p trend = 0.04 ], and nonobese men [OR = 2.04 (95% CI: 0.99, 4.19), p trend = 0.03 ]. Similar patterns of associations were observed for intensity-weighted lifetime days of glyphosate use.

DISCUSSION

High lifetime glyphosate use could be associated with mLOY affecting a larger fraction of cells, suggesting glyphosate could confer genotoxic or selective effects relevant for clonal expansion. As the first study to investigate this association, our findings contribute novel evidence regarding the carcinogenic potential of glyphosate and require replication in future studies. https://doi.org/10.1289/EHP12834.

Sperm DNA damage: The possible link between obesity and male infertility, an update of the current literature

Obesity prevalence worldwide is increasing significantly. Whilst maternal obesity has clear detrimental impacts on fertility, pregnancy and foetal outcomes, more recently there has been an increasing focus on the role of paternal obesity in human fertility. Recent meta-analyses have indicated that obesity in men negatively affects basic sperm parameters such as sperm count, concentration and motility, increases the incidence of infertility and reduces the chances of conception. Sperm DNA damage, typically characterised by DNA strand breaks and oxidation of DNA nucleotides, is a specialised marker of sperm quality that has been independently associated with recurrent miscarriage, reduced assisted reproduction success and increased mutational loads in subsequent offspring. Whilst, there are still conflicting data in humans as to the association of obesity in men with sperm DNA damage, evidence from rodent models is clear, indicating that male obesity increases sperm DNA damage. Human data are often conflicting because of the large heterogeneity amongst studies, the use of body mass index as the indicator of obesity and the methods used for detection of sperm DNA damage. Furthermore, comorbidities of obesity (i.e., heat stress, adipokines, insulin resistance, changes in lipids, hypogonadism and obstructive sleep apnoea) are also independently associated with increased sperm DNA damage that is not always modified in men with obesity, and as such may provide a causative link to the discrepancies amongst human studies. In this review, we provide an update on the literature regarding the associations between obesity in men and fertility, basic sperm parameters and sperm DNA damage. We further discuss potential reasons for the discrepancies in the literature and outline possible direct and indirect mechanisms of increased sperm DNA damage resulting from obesity. Finally, we summarise intergenerational obesity through the paternal linage and how sperm DNA damage may contribute to the transmission.

Quantifying telomere transcripts as tool to improve risk assessment for genetic instability and genotoxicity

Telomere repeat-containing RNAs (TERRA) are transcribed from telomeres as long non-coding RNAs and are part of the telomere structure with protective function. The genetic stability of cells requires telomeric repeats at the ends of chromosomes. Maintenance of telomere length (TL) is essential for proliferative capacity and chromosomal integrity. In contrast, telomere shortening is a recognized risk factor for carcinogenesis and a biomarker of aging due to the cumulative effects of environmental exposures and life experiences such as trauma or stress. In this context, telomere repeats are lost due to cell proliferation, but are also susceptible to stress factors including reactive oxygen species (ROS) inducing oxidative base damage. Quantitative PCR (qPCR) of genomic DNA is an established method to analyze TL as a tool to detect genotoxic events. That same qPCR method can be applied to RNA converted into cDNA to quantify TERRA as a useful tool to perform high-throughput screenings. This short review summarizes relevant qPCR studies using both TL and TERRA quantification, provides an overall view of the molecular mechanisms of telomere protection against ROS by TERRA, and summarizes the presented studies comparing the results at DNA and RNA levels, which indicate that fluctuations at transcript level might reflect a short-term response. Therefore, we conclude that performing both of these measurements together will improve genotoxicity studies.

Impact of mobile phone-specific electromagnetic fields on DNA damage caused by occupationally relevant exposures: results of ex vivo experiments with peripheral blood mononuclear cells from different demographic groups

The aim of this study was to investigate if age and body mass of humans have an impact on the DNA-damaging properties of high-frequency mobile phone-specific electromagnetic fields (HF-EMF, 1950 MHz, universal mobile telecommunications system, UMTS signal) and if this form of radiation has an impact on the genotoxic effects of occupationally relevant exposures. Pooled peripheral blood mononuclear cells (PBMC) from three groups [young normal weight, young obese (YO), and older age normal weight individuals] were exposed to different doses of HF-EMF (0.25, 0.5, and 1.0 W/kg specific absorption rate-SAR) and simultaneously or sequentially to different chemicals which cause DNA damage (CrO3, NiCl2, benzo[a]pyrene diol epoxide-BPDE, and 4-nitroquinoline 1-oxide-4NQO) via different molecular mechanisms. We found no difference in regard to the background values in the three groups but a significant increase of DNA damage (81% without and 36% with serum) in cells from old participants after radiation with 1.0 W/kg SAR 16 h. In combined treatment experiments we found no impact of the UMTS signal on chemically induced DNA damage in the different groups in general. However, a moderate decrease of DNA damage was seen in simultaneous treatment experiments with BPDE and 1.0 W/kg SAR in the YO group (decline 18%). Taken together our findings indicate that HF-EMF cause DNA damage in PBMC from older subjects (69.1 years). Furthermore, they show that the radiation does not increase induction of DNA damage by occupationally relevant chemicals.

The moderating role of macronutrient intake in relation to body composition and genotoxicity: A study with gym users

In a cross-sectional study of gymnasium users (both sexes, ages = 41.9 ± 14.8 years), we examined the moderating role of macronutrient intake in relation to body composition and genotoxicity. A questionnaire was administered to evaluate characteristics of the participants. To assess macronutrient consumption, we used 24-h food recalls on three non-consecutive days. Body composition (body fat percentage and muscle mass) was evaluated with a bioimpedance scale. Genotoxicity was assessed with the buccal micronucleus cytome assay. Multiple linear regression models were applied, adjusting for age; sex; tobacco and alcohol consumption; and (with regard to exercise habits) frequency, training time, intensity, and types. Micronucleus frequency was directly associated with body fat and inversely associated with muscle mass. Our study shows that carbohydrate and fat intakes affect body fat percentage and micronucleus frequency in gymnasium users.

Use of the Single Cell Gel Electrophoresis Assay for the Detection of DNA-protective Dietary Factors: Results of Human Intervention Studies

The single cell gel electrophoresis technique is based on the measurement of DNA migration in an electric field and enables to investigate via determination of DNA-damage the impact of foods and their constituents on the genetic stability. DNA-damage leads to adverse effects including cancer, neurodegenerative disorders and infertility. In the last 25 years approximately 90 human intervention trials have been published in which DNA-damage, formation of oxidized bases, alterations of the sensitivity towards reactive oxygen species and chemicals and of repair functions were investigated with this technique. In approximately 50% of the studies protective effects were observed. Pronounced protection was found with certain plant foods (spinach, kiwi fruits, onions), coffee, green tea, honey and olive oil. Also diets with increased contents of vegetables caused positive effects. Small amounts of certain phenolics (gallic acid, xanthohumol) prevented oxidative damage of DNA; with antioxidant vitamins and cholecalciferol protective effects were only detected after intake of doses that exceed the recommended daily uptake values. The evaluation of the quality of the studies showed that many have methodological shortcomings (lack of controls, no calibration of repair enzymes, inadequate control of the compliance and statistical analyses) which should be avoided in future investigations.

Impact of Bariatric Surgery on the Stability of the Genetic Material, Oxidation, and Repair of DNA and Telomere Lengths

Obesity causes genetic instability, which plays a key-role in the etiology of cancer and aging. We investigated the impact of bariatric surgery (BS) on DNA repair, oxidative DNA damage, telomere lengths, alterations of antioxidant enzymes and, selected proteins which reflect inflammation. The study was realized with BS patients (n = 35). DNA damage, base oxidation, BER, and NER were measured before and 1 month and 6 months after surgery with the single-cell gel electrophoresis technique. SOD and GPx were quantified spectrophotometrically, malondealdehyde (MDA) was quantified by HPLC. Telomere lengths were determined with qPCR, and plasma proteome profiling was performed with high-resolution mass spectrophotometry. Six months after the operations, reduction of body weight by 27.5% was observed. DNA damage decreased after this period, this effect was paralleled by reduced formation of oxidized DNA bases, a decline in the MDA levels and of BER and NER, and an increase in the telomere lengths. The activities of antioxidant enzymes were not altered. Clear downregulation of certain proteins (CRP, SAA1) which reflect inflammation and cancer risks was observed. Our findings show that BS causes reduced oxidative damage of DNA bases, possibly as a consequence of reduction of inflammation and lipid peroxidation, and indicate that the surgery has beneficial long-term health effects.

Single 30 min treadmill exercise session suppresses the production of pro-inflammatory cytokines and oxidative stress in obese female adolescents

OBJECTIVES

Regular treadmill exercise may result in changes in pro-inflammatory cytokines and oxidative stress. However, the way acute treadmill exercise mechanisms affect the changes in pro-inflammatory cytokines and oxidative stress in obese has not been comprehensively exposed. This study aimed to analyze the pro-inflammatory cytokines and oxidative stress between 30 min before treadmill exercise and 24 h after treadmill exercise in obese adolescents.

METHODS

A total of 20 obese females aged 19-24 years were recruited from female students and given one session of treadmill exercise with an intensity of 60-70% HR_max. Thiobarbituric acid reactive substance (TBARS) was used to analyze serum levels of MDA, while enzyme-linked immunosorbent assay (ELISA) was used to analyze serum levels of TNF-α and IL-6. Moreover, the independent samples t-test with a significance level of 5% was employed to have the statistical analysis.

RESULTS

The results on 24 h after treadmill exercise and delta (Δ) between CTRL and TREG showed a significant difference (p<0.001).

CONCLUSIONS

This study found a decrease in pro-inflammatory cytokines and oxidative stress 24 h after treadmill exercise in obese adolescents. Therefore, treadmill exercise can be a promising strategy for preventing adolescents from obesity as well as preventing disease risks associated with oxidative stress and chronic inflammation.

Combined Approach: FFQ, DII, Anthropometric, Biochemical and DNA Damage Parameters in Obese with BMI ≥ 35 kg m-2

Although obesity with its comorbidities is linked with higher cancer risk, the data on genome stability in the obese/severely obese are scarce. This is the first study with three DNA damage assessment assays (Fpg-modified and alkaline comet assays and micronucleus cytome assay) performed on a severely obese population (n = 53) where the results were compared with daily intake of food groups, nutrient intake, dietary inflammatory index (DII), and anthropometric and biochemical parameters usually measured in obese individuals. Results demonstrated the association between DNA damage levels and a decrease in cell proliferation with anthropometric measurements and the severity of obese status, together with elevated levels of urates, inorganic phosphates, chlorides, and hs troponin I levels. DII was connected with oxidative DNA damage, while BMI and basal metabolic rate (BMR) were associated with a decrease in cell proliferation and DNA damage creation. Measured daily BMR and calculated daily energy intake from the food frequency questionnaire (FFQ) demonstrated no significant difference (1792.80 vs. 1869.86 kcal day-1 mean values). Groups with higher DNA damage than expected (tail intensity in comet assay >9% and >12.4%, micronucleus frequency >13), consumed daily, weekly, and monthly more often some type of food groups, but differences did not show a clear influence on the elevated DNA damage levels. Combination of all three DNA damage assays demonstrated that some type of damage can start earlier in the obese individual lifespan, such as nuclear buds and nucleoplasmic bridges, then comes decrease in cell proliferation and then elevated micronucleus frequencies, and that primary DNA damage is not maybe crucial in the overweight, but in severely obese. Biochemically changed parameters pointed out that obesity can have an impact on changes in blood cell counts and division and also on genomic instability. Assays were able to demonstrate groups of sensitive individuals that should be further monitored for genomic instability and cancer prevention, especially when obesity is already connected with comorbidities, 13 different cancers, and a higher mortality risk with 7-10 disease-free years loss. In the future, both DNA damage and biochemical parameters should be combined with anthropometric ones for further obese monitoring, better insight into biological changes in the severely obese, and a more individual approach in therapy and treatment. Patients should also get a proper education about the foodstuff with pro- and anti-inflammatory effect.

DNA damage response signaling: A common link between cancer and cardiovascular diseases

DNA damage response (DDR) signaling ensures genomic and proteomic homeostasis to maintain a healthy genome. Dysregulation either in the form of down- or upregulation in the DDR pathways correlates with various pathophysiological states, including cancer and cardiovascular diseases (CVDs). Impaired DDR is studied as a signature mechanism for cancer; however, it also plays a role in ischemia-reperfusion injury (IRI), inflammation, cardiovascular function, and aging, demonstrating a complex and intriguing relationship between cancer and pathophysiology of CVDs. Accordingly, there are increasing number of reports indicating higher incidences of CVDs in cancer patients. In the present review, we thoroughly discuss (1) different DDR pathways, (2) the functional cross talk among different DDR mechanisms, (3) the role of DDR in cancer, (4) the commonalities and differences of DDR between cancer and CVDs, (5) the role of DDR in pathophysiology of CVDs, (6) interventional strategies for targeting genomic instability in CVDs, and (7) future perspective.

Association between DNA repair capacity and body mass index in women

OBJECTIVE

Examine whether DNA repair capacity (DRC) levels are associated with body mass index (BMI) in adult women.

DESIGN AND PARTICIPANTS

A nested study composed of 539 women without breast cancer (BC) from a case-control BC study in addition to 104 that were recruited later for a total of 643.

MEASUREMENTS

DRC levels were measured in lymphocytes using a host-cell reactivation assay with a luciferase reporter gene damaged by UVC. This assay measures the efficiency of nucleotide excision repair (NER). Log-binomial regression model was used. The prevalence ratio (PR) was used to evaluate the magnitude of the association between the BMI and DRC levels. An assessment of interaction terms was performed with the likelihood ratio test. The confounding effect was assessed by comparing the point estimates of the crude and adjusted PR.

RESULTS

The 75th percentiles of DRC levels of the women with a BMI between 18 and 25 and > 25 showed statistically significant differences. The prevalence of a DRC ≤ 5 % among women with BMI > 25 is 1.24 (95 % CI: 1.03, 1.48) times the prevalence of having a DRC ≤ 5 % among the women with BMI ≤ 25 after adjustments for different covariates. This excess was statistically significant (p < 0.05). Women with a family history of cancer had an estimated PR of 1.25 (95 % CI, 0.87-1.39; P ≥ 0.05); and women with no family history of cancer, the estimated PR was 1.6 (95 % CI, 1.14-2.22; p ≤ 0.05).

CONCLUSIONS

Women with BMI > 25 tend to have lower DRC levels. When having a family history of cancer, the PR of low DRC levels in overweight/obese individuals was not statistically significant. However, the PR of low levels of DRC in overweight/obese individuals with no family history of cancer was statistically significant.

DNA damage and antioxidant capacity in COPD patients with and without lung cancer

Background and objective

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation of the lower airways, and COPD patients show two to five times higher risk of lung cancer than smokers with normal lung function. COPD is associated with increased oxidative stress, which may cause DNA damage and lung carcinogenesis. Our aim was to evaluate DNA damage and oxidative stress (lipid peroxidation and antioxidant status) and their relationship in patients with COPD with and without lung cancer.

Methods

We evaluated 18 patients with COPD, 18 with COPD with lung cancer, and 18 controls (former or current smokers). DNA damage was evaluated in peripheral blood lymphocytes using a comet assay; the concentration of malondialdehyde (MDA) and hydrophilic antioxidant performance (HAP) were measured in the plasma.

Results

DNA damage was higher in patients with COPD with cancer than in the controls (p = 0.003). HAP was significantly lower in patients with COPD with cancer than in those without cancer and controls. The presence of lung cancer and COPD showed a positive association with DNA strand breaks and the concentration of MDA.

Conclusion

COPD with lung cancer was associated with elevated DNA damage in peripheral lymphocytes, and cancer and COPD showed a positive correlation with DNA damage. The antioxidant capacity showed a negative association with the interaction COPD and cancer and presence of COPD. The mechanisms underlying the increased incidence of lung cancer in COPD are unknown; DNA damage may be involved. Further research may provide insights into their development and treatment.

Antitoxic Effects of Curcumin against Obesity-Induced Multi-Organs' Biochemical and Histopathological Abnormalities in an Animal Model

Background

Obesity is a significant public health problem that is characterized by an increase in oxidative stress and enhanced inflammatory responses associated with immune cell invasion of adipose tissues. This study assessed several biochemical abnormalities, apoptosis, oxidative stress status, and associated histological changes in the liver, duodenum, and heart brought on by high-fat diet-induced obesity in rats. It also assessed the mechanistic benefits of curcumin in reversing these inflammatory, metabolic, and histological impairments.

Methods

Rats were assigned into three groups each including ten rats: the control group (CD), the high-fat diet group (HFD), and the high-fat diet + curcumin (HFDC) group. Serum glucose, insulin, and triglycerides (TAGs) were observed. In addition, apoptosis (indicated by hepatic DNA fragmentation) and oxidative stress status (indicated by hepatic MPO, GSH, and SOD) were assessed. Histopathological examinations included the GIT (liver and duodenum) and heart in addition to quantitative real-time polymerase chain reaction (qRT-PCR) assays of the adipose tissue genetic expressions for inflammatory signaling pathways (TLR4, IL-6, and TNF-α).

Results

The overall findings showed that the HFD group exhibited significantly higher levels of glucose, TAGs, and insulin than the control group (P < 0.01). The histological abnormalities of the studied organs in the HFD group were paralleled by these biochemical abnormalities, which were strongly associated with increased apoptosis, increased oxidative stress, and increased expression of the inflammatory signaling markers. There were significant improvements in the HFDC group in terms of biochemical, inflammatory, and histological investigations.

Conclusions

This study's findings concluded that obesity is significantly associated with biochemical and microscopic alterations in many organs. Curcumin exerted potent antitoxic, antioxidant, tissue-protective, and antiobesity effects. Curcumin is recommended to be added to various dietary regimens to prevent or delay the organs' dysfunction among obese people.

Obesity, inflammation, and cancer in dogs: Review and perspectives

Obesity is the most common nutritional disease in dogs, and its prevalence has increased in recent decades. Several countries have demonstrated a prevalence of obesity in dogs similar to that observed in humans. Chronic low-grade inflammation is a prominent basis used to explain how obesity results in numerous negative health consequences. This is well known and understood, and recent studies have pointed to the association between obesity and predisposition to specific types of cancers and their complications. Such elucidations are important because, like obesity, the prevalence of cancer in dogs has increased in recent decades, establishing cancer as a significant cause of death for these animals. In the same way, intensive advances in technology in the field of human and veterinary medicine (which even proposes the use of animal models) have optimized existing therapeutic methods, led to the development of innovative treatments, and shortened the time to diagnosis of cancer. Despite the great challenges, this review aims to highlight the evidence obtained to date on the association between obesity, inflammation, and cancer in dogs, and the possible pathophysiological mechanisms that link obesity and carcinogenesis. The potential to control cancer in animals using existing knowledge is also presented.

Obesity: a perfect storm for carcinogenesis

Obesity-related cancers account for 40% of the cancer cases observed in the USA and obesity is overtaking smoking as the most widespread modifiable risk factor for carcinogenesis. Here, we use the hallmarks of cancer framework to delineate how obesity might influence the carcinogenic hallmarks in somatic cells. We discuss the effects of obesity on (a) sustaining proliferative signaling; (b) evading growth suppressors; (c) resisting cell death; (d) enabling replicative immortality; (e) inducing angiogenesis; (f) activating invasion and metastasis; (g) reprogramming energy metabolism; and (h) avoiding immune destruction, together with its effects on genome instability and tumour-promoting inflammation. We present the current understanding and controversies in this evolving field, and highlight some areas in need of further cross-disciplinary focus. For instance, the relative importance of the many potentially causative obesity-related factors is unclear for each type of malignancy. Even within a single tumour type, it is currently unknown whether one obesity-related factor consistently plays a predominant role, or if this varies between patients or, even in a single patient with time. Clarifying how the hallmarks are affected by obesity may lead to novel prevention and treatment strategies for the increasingly obese population.

Obesity-related genomic instability and altered xenobiotic metabolism: possible consequences for cancer risk and chemotherapy

The increase in the prevalence of obesity has led to an elevated risk for several associated diseases including cancer. Several studies have investigated the DNA damage in human blood samples and showed a clear trend towards increased DNA damage in obesity. Reduced genomic stability is thus one of the consequences of obesity, which may contribute to the related cancer risk. Whether this is influenced by compromised DNA repair has not been elucidated sufficiently yet. On the other hand, obesity has also been linked to reduced therapy survival and increased adverse effects during chemotherapy, although the available data are controversial. Despite some indications that obesity might alter hepatic metabolism, current literature in humans is insufficient, and results from animal studies are inconclusive. Here we have summarised published data on hepatic drug metabolism to understand the impact of obesity on cancer therapy better. Furthermore, we highlight knowledge gaps in the interrelationship between obesity and drug metabolism from a toxicological perspective.

Young transgenic hMTH1 mice are protected against dietary fat-induced metabolic stress-implications for enhanced longevity

hMTH1 protects against mutation during oxidative stress. It degrades 8‐oxodGTP to exclude potentially mutagenic oxidized guanine from DNA. hMTH1 expression is linked to ageing. Its downregulation in cultured cells accelerates RAS‐induced senescence, and its overexpression in hMTH1‐Tg mice extends lifespan. In this study, we analysed the effects of a brief (5 weeks) high‐fat diet challenge (HFD) in young (2 months old) and adult (7 months old) wild‐type (WT) and hMTH1‐Tg mice. We report that at 2 months, hMTH1 overexpression ameliorated HFD‐induced weight gain, changes in liver metabolism related to mitochondrial dysfunction and oxidative stress. It prevented DNA damage as quantified by a comet assay. At 7 months old, these HFD‐induced effects were less severe and hMTH1‐Tg and WT mice responded similarly. hMTH1 overexpression conferred lifelong protection against micronucleus induction, however. Since the canonical activity of hMTH1 is mutation prevention, we conclude that hMTH1 protects young mice against HFD by reducing genome instability during the early period of rapid growth and maximal gene expression. hMTH1 protection is redundant in the largely non‐growing, differentiated tissues of adult mice. In hMTH1‐Tg mice, expression of a less heavily mutated genome throughout life provides a plausible explanation for their extended longevity.

Changes in anthropometric, biochemical, oxidative, and DNA damage parameters after 3-weeks-567-kcal-hospital-controlled-VLCD in severely obese patients with BMI ≥ 35 kg m-2

BACKGROUND & AIMS

Severe obesity and its comorbidities relate to increased genomic instability/cancer risk. Obesity in Croatia is rapidly increasing, and long diets are sometimes the reason for obese to quit health improvement programs. A shorter diet with more strict calorie reduction could also lead to weight reduction and health improvements, but data are scarce. We tested for the first time if a very low-calorie diet (VLCD) can improve anthropometric, biochemical and genomic stability parameters in severely obese with BMI ≥ 35 kg m^-2.

METHODS

22 participants were chosen among those regularly attending the hospital for obesity control, with no other previous treatment for bodyweight reduction. Under 24 h medical surveillance, patients received 3-weeks-567-kcal-hospital-controlled-VLCD composed of 50-60% complex carbohydrates, 20-25% proteins, and 25-30% fat, with the attention to food carbo-glycemic index, in 3 meals freshly prepared in hospital. We analyzed changes in body weight, BMI, basal metabolism rate, waist-hip ratio, visceral fat level, body fat mass, percent body fat, skeletal muscle mass, basal metabolism, energy intake, lipid profile, thyroid hormones, TSH, and genomic instability (alkaline and oxidative FPG comet assay) before and on the last VLCD day.

RESULTS

Diet caused BMI reduction (in average 3-4 BMI units' loss), excessive weight loss (between 10 and 35%), significant weight loss (average 9 kg, range 4.8-14.4 kg) and a significant decrease in glucose, insulin, urea, cholesterol, HDL-c, LDL-c, oxidative (FPG) and DNA damage (alkaline comet assay) levels.

CONCLUSIONS

The diet can lead to ≥10% excessive weight loss, significant health, and genomic stability improvement, and keep severely obese interest in maintaining healthy habits. The study was registered at ClinicalTrials.gov as NCT05007171 (10.08.2021).

A pooled analysis of molecular epidemiological studies on modulation of DNA repair by host factors

Levels of DNA damage represent the dynamics between damage formation and removal. Therefore, to better interpret human biomonitoring studies with DNA damage endpoints, an individual's ability to recognize and properly remove DNA damage should be characterized. Relatively few studies have included DNA repair as a biomarker and therefore, assembling and analyzing a pooled database of studies with data on base excision repair (BER) was one of the goals of hCOMET (EU-COST CA15132). A group of approximately 1911 individuals, was gathered from 8 laboratories which run population studies with the comet-based in vitro DNA repair assay. BER incision activity data were normalized and subsequently correlated with various host factors. BER was found to be significantly higher in women. Although it is generally accepted that age is inversely related to DNA repair, no overall effect of age was found, but sex differences were most pronounced in the oldest quartile (>61 years). No effect of smoking or occupational exposures was found. A body mass index (BMI) above 25 kg/m2 was related to higher levels of BER. However, when BMI exceeded 35 kg/m2, repair incision activity was significantly lower. Finally, higher BER incision activity was related to lower levels of DNA damage detected by the comet assay in combination with formamidopyrimidine DNA glycosylase (Fpg), which is in line with the fact that oxidatively damaged DNA is repaired by BER. These data indicate that BER plays a role in modulating the steady-state level of DNA damage that is detected in molecular epidemiological studies and should therefore be considered as a parallel endpoint in future studies.

The Influence of Environmental Polycyclic Aromatic Hydrocarbons (PAHs) Exposure on DNA Damage among School Children in Urban Traffic Area, Malaysia

This study aimed to investigate the association between particulate PAHs exposure and DNA damage in Malaysian schoolchildren in heavy traffic (HT) and low traffic (LT) areas. PAH samples at eight schools were collected using a low volume sampler for 24 h and quantified using Gas Chromatography-Mass Spectrometry. Two hundred and twenty-eight buccal cells of children were assessed for DNA damage using Comet Assay. Monte-Carlo simulation was performed to determine incremental lifetime cancer risk (ILCR) and to check the uncertainty and sensitivity of the estimated risk. Total PAH concentrations in the schools in HT area were higher than LT area ranging from 4.4 to 5.76 ng m^-3 and 1.36 to 3.79 ng m^-3, respectively. The source diagnostic ratio showed that PAHs in the HT area is pyrogenic, mainly from diesel emission. The 95th percentile of the ILCR for children in HT and LT area were 2.80 × 10^-7 and 1.43 × 10^-7, respectively. The degree of DNA damage was significantly more severe in children in the HT group compared to LT group. This study shows that total indoor PAH exposure was the most significant factor that influenced the DNA damage among children. Further investigation of the relationship between PAH exposure and genomic integrity in children is required to shed additional light on potential health risks.

Effects of a 3-Week Hospital-Controlled Very-Low-Calorie Diet in Severely Obese Patients

Although a very-low-calorie diet (VLCD) is considered safe and has demonstrated benefits among other types of diets, data are scarce concerning its effects on improving health and weight loss in severely obese patients. As part of the personalized weight loss program developed at the Duga Resa Special Hospital for Extended Treatment, Croatia, we evaluated anthropometric, biochemical, and permanent DNA damage parameters (assessed with the cytochalasin B-blocked micronucleus cytome assay-CBMN) in severely obese patients (BMI ≥ 35 kg m-2) after 3-weeks on a 567 kcal, hospital-controlled VLCD. This is the first study on the permanent genomic (in)stability in such VLCD patients. VLCDs caused significant decreases in weight (loss), parameters of the lipid profile, urea, insulin resistance, and reduced glutathione (GSH). Genomic instability parameters were lowered by half, reaching reference values usually found in the healthy population. A correlation was found between GSH decrease and reduced DNA damage. VLCDs revealed susceptible individuals with remaining higher DNA damage for further monitoring. In a highly heterogeneous group (class II and III in obesity, differences in weight, BMI, and other categories) consisting of 26 obese patients, the approach demonstrated its usefulness and benefits in health improvement, enabling an individual approach to further monitoring, diagnosis, treatment, and risk assessment based on changing anthropometric/biochemical VLCD parameters, and CBMN results.

Folate deficiency enhances the in vitro genotoxicity of bile acids in human colon and liver cells

Obese subjects have a high baseline of genotoxic stress, but the underlying mechanism is poorly understood. Given that obesity is associated with high bile acids (BA) and low folate, we aimed to determine the interactive effect of folate deficient or supplementation to the genotoxicity and cytotoxicity of BA in human colon and liver cells. NCM460 and L-02 cells were cultured in folate deficient (22.6 nM) and replete (2260 nM) RPMI 1640 medium with or without 50 μM deoxycholic acid (DCA) or lithocholic acid (LCA) for 7 days. Moreover, these cells were cultured in folate supplemented (5.65, 11.3 and 22.6 μM) and standard (2.26 μM) medium with 200 μM DCA or LCA for 7 days. Genotoxicity and cytotoxicity were measured using the cytokinesis-block micronucleus cytome assay. Our results showed that under folate-replete condition, 50 μM DCA or LCA significantly increased the rate of micronuclei in NCM460 and L-02 cells. Significantly, the micronuclei-inducing effect of 50 μM DCA or LCA was further enhanced by folate deficiency. Interestingly, folate supplementation exerted a dose-dependent manner to significantly decrease the rates of micronuclei, nucleoplasmic bridges, nuclear buds, apoptosis and necrosis induced by 200 μM DCA or LCA in NCM460 and L-02 cells. In conclusion, the genotoxicity of moderate BA (50 μM) was exacerbated by folate deficiency and folate supplementation could efficiently protect cells against the genotoxicity and cytotoxicity of high BA (200 μM).

Environmental exposure to mineral coal and by-products: Influence on human health and genomic instability

Environmental exposure to pollution generated by mining and burning coal is inevitable for people living nearby. Therefore, the aim of this study was to evaluate the influence of coal dust on health conditions and genomic instability of individuals who live near coal mines and thermoelectric power plants, and to relate the results to inorganic elements and inflammatory responses. Thus, we evaluated 284 individuals from four cities in the south of Brazil around a region with coal mines and a thermoelectric power plant (one city was considered a negative control). The results of the Comet assay and Micronucleus (MN) test did not show a genotoxic or mutagenic effect related to environmental exposure to coal, but the inflammatory cytokine tumor necrosis factor-α (TNF-α) was increased in all cities around the power plant when compared to the control conditions. Higher levels of MN were associated with body mass index and cardiovascular risk, and higher levels of Damage Index (DI), TNF-α and interleukin1β (IL-1β) with number of cigarettes/day. Principal component analysis (PCA) was used to integrate DNA damage and inflammatory results with inorganic elements. This study also demonstrated the relationship between zinc and MN, copper, and interleukin10 (IL-10), and among silicon and sulfur with DI and nucleoplasmic bridge. A relationship was also observed between the reduction of inorganic elements and both aging and quality of health. The use of different methodologies and the relationship between the results obtained in these studies, including different lifestyles, can increase the understanding of the interaction between this mineral and the health status of residents of regions affected by coal pollution.

Effects of Zingiber officinale extract supplementation on metabolic and genotoxic parameters in diet-induced obesity in mice

Obesity is an epidemic associated with many diseases. The nutraceutical Zingiber officinale (ZO) is a potential treatment for obesity; however, the molecular effects are unknown. Swiss male mice were fed a high-fat diet (59 % energy from fat) for 16 weeks to generate a diet-induced obesity (DIO) model and then divided into the following groups: standard diet + vehicle; standard diet + ZO; DIO + vehicle and DIO + ZO. Those in the ZO groups were supplemented with 400 mg/kg per d of ZO extract (oral administration) for 35 d. The animals were euthanised, and blood, quadriceps, epididymal fat pad and hepatic tissue were collected. DIO induced insulin resistance, proinflammatory cytokines, oxidative stress and DNA damage in different tissues. Treatment with ZO improved insulin sensitivity as well as decreased serum TAG, without changes in body weight or adiposity index. TNF-α and IL-1β levels were lower in the liver and quadriceps in the DIO + ZO group compared with the DIO group. ZO treatment reduced the reactive species and oxidative damage to proteins, lipids and DNA in blood and liver in obese animals. The endogenous antioxidant activity was higher in the quadriceps of DIO + ZO. These results in the rat model of DIO may indicate ZO as an adjuvant on obesity treatment.

Multi- and trans-generational disturbances of perfluorobutane sulfonate and perfluorohexane sulfonate on lipid metabolism in Caenorhabditis elegans

Short-chained perfluorobutane sulfonate (PFBS, four-carbon) and perfluorohexane sulfonate (PFHxS, six-carbon) are widely employed to substitute long-chained per- and poly-fluoroalkyl substances (PFASs). Recent studies showed the potential persistence of PFBS and PFHxS, and also reported their correlation with obesity. However, the long-term outcome and underlying mechanisms remained poorly understood. Presently, the effects of PFBS and PFHxS were studied on C. elegans with multi- and trans-generational experiments. The multi-generational effects were measured in continuous four generational exposure (i.e., F1 to F4). Results showed that PFBS did not stimulate the fat content in F1 but in F4 with continuous but different disturbances on the lipid metabolism and the insulin and insulin-like (IIS) pathway. PFHxS stimulated the fat content in F1 and F4 with similar disturbances on the lipid metabolism and IIS pathway. The trans-generational results showed that the effects of PFBS and PFHxS on the lipid metabolism and IIS pathway were not totally recovered in the offspring of F1 (i.e., T1-T3) and F4 (i.e., T1'-T3') which were not continuously exposed. PFHxS showed a common pattern to up-regulate daf-7 in both multi- and trans-generational effects. The long-term consequences of the short-chained PFASs substitutes should be concerned and epigenetic regulations should be considered in future mechanism studies.

Aşırı Kilolu Kişilerde Olası Genotoksik Hasarın Analizi

Amaç: Son yıllarda yapılmış olan araştırmalar ile obezitenin, DNA zincir kırıklarının onarım mekanizmasını değiştirdiği ortaya çıkartılmıştır. Ayrıca Beden Kütle indeksinde artış ile genomik kararsızlık arasında ilişki tespit edilmiştir. Sunulan çalışmada aşırı kilolu bireylerin muhtemel genotoksik hasarının araştırılması amaçlanmış olup periferal kan örneklerinde Tek Hücre Jel Elektroforezi deneyi kullanılarak olası genotoksik hasar düzeyi hesaplanmıştır. Gereç ve Yöntemler: Sunulan çalışmada 18 yaşından büyük aşırı kilolu ya da normal kiloya sahip bireylerin periferal lenfositlerinde olası DNA hasarı comet deneyi ile analiz edilmiştir. Sonuçlar SPSS analiz programı kullanılarak istatistiksel olarak karşılaştırılmıştır. Bulgular: Sunulan araştırmaya yaş ortalaması 30,13±7,97 olan 23 kadın ve yaş ortalaması 38,13±10,63 olan 32 erkek toplamda 55 sayıda gönüllü katılmıştır. DNA hasarının göstergesi olan kuyruk momenti değeri tüm bireylerde ortalama 1,21±0,45’dir. Aşırı kilolu kişilerin kuyruk momenti değeri ortalama 1,29±0,46 olarak bulunmuştur. Bu değer normal kiloya sahip bireylerin kuyruk momenti sonuçları (1,09±0,40) ile karşılaştırıldığında istatistiksel olarak anlamlı derecede fark bulunmamıştır (p>0.05). Çalışma sonuçlarımıza göre beden kitle indeksinde artış ile DNA hasarı arasında anlamlı fark bulunmamıştır (p>0.05). Sonuç: Sunulan çalışma Türkiye’deki yetişkin bireylerde aşırı kiloluluk ve DNA hasar düzeyinin değerlendirildiği ilk çalışma olma özelliğindedir. Gelecekte obeziteye ya da metabolik sendroma sahip kişilerde DNA hasar düzeyinin genotoksisite testleriyle araştırılacağı yeni çalışmaların yapılması önerilmektedir.

Assessment of Cytogenetic Damage and Cholinesterases' Activity in Workers Occupationally Exposed to Pesticides in Zamora-Jacona, Michoacan, Mexico

Pesticides have been considered as potential chemical mutagens; however, little is known about toxic and genotoxic effects during pesticide application in Zamora-Jacona, Michoacan State in Mexico. This study sought to determine DNA damage and cholinesterase activities inhibitions in 54 agricultural workers exposed to complex mixtures of pesticides vs. control group (26 individuals) using Comet assay in peripheral whole blood, micronucleus (MN) test in oral mucosa cells, Cytokinesis-blocked MN assay in lymphocytes (L-CBMNcyt) and measuring AChE and BChE activities in whole blood and plasma samples, respectively. Exposed subjects demonstrated significantly elevated levels of primary (Comet assay: tail intensity, tail length, tail moment, Olive tail moment) and permanent DNA damage (MN assay: in blood/buccal cells; frequencies of nuclear buds, binucleated cells, cells with condensed chromatin, karyorrhexis, pyknosis, and karyolysis). However, inhibition of cholinesterase activities (AChE and BChE) was not observed in the workers. Confounding factors including sex, age, BMI, working exposure period, protection level, smoking habit (cigarettes per day units), alcohol consumption (weekly), medication, were considered in the analysis. These combined techniques demonstrated usefulness in the health hazards risks pesticide exposure assessment and suggested the need for periodic monitoring together with the education and the training of occupational workers for the safe application of potentially harmful pesticides.

Association between Food Intake, Clinical and Metabolic Markers and DNA Damage in Older Subjects

The use of DNA damage as marker of oxidative stress, metabolic dysfunction and age-related diseases is debated. The present study aimed at assessing the level of DNA damage (evaluated as DNA strand-breaks, endogenous and oxidatively-induced DNA damage) in a group of older subjects with intestinal permeability enrolled within the MaPLE (Gut and Blood Microbiomics for Studying the Effect of a Polyphenol-Rich Dietary Pattern on Intestinal Permeability in the Elderly) intervention trial, to evaluate its association with clinical, metabolic and dietary markers. DNA damage in peripheral blood mononuclear cells was assessed by the comet assay in 49 older subjects participating in the study. Clinical and metabolic markers, markers of inflammation, vascular function and intestinal permeability were determined in serum. Food intake was estimated by weighted food diaries. On the whole, a trend towards higher levels of DNA damage was observed in men compared to women (p = 0.071). A positive association between DNA damage and clinical/metabolic markers (e.g., uric acid, lipid profile) and an inverse association with dietary markers (e.g., vitamin C, E, B₆, folates) were found and differed based on sex. By considering the importance of DNA stability during aging, the results obtained on sex differences and the potential role of dietary and metabolic factors on DNA damage underline the need for further investigations in a larger group of older adults to confirm the associations found and to promote preventive strategies.

The Effects of Combined Physical Exercise on Serum Redox Biomarkers and Leukocyte DNA Damage of Obese Women

Obesity is usually linked to oxidative stress, which can lead to damage to biomolecules. The combination of aerobic and strength exercises seems to induce health benefits in obese individuals, but little is known about the effects of combined physical exercise on redox homeostasis and DNA damage in this population. Thus, the aim of the current study was to determine the effects of 16 weeks of combined physical exercise on biomarkers of oxidative stress and DNA damage in obese women. 17 obese women underwent 16 weeks of a combined physical training program, 3 times per week. Anthropometric and biochemical parameters, serum superoxide dismutase (SOD) and glutathione peroxidase activity, plasma 8-isoprostane levels, and DNA and chromosomal damage were evaluated before and after physical training. Combined physical exercise training decreased body weight (83.2 ± 9.6 vs. 80.2 ± 9.6 kg), body mass index (33.8 ± 3.6 vs. 32.6 ± 3.7 kg·m-2), body fat (40.2 ± 2.6 vs. 39.0 ± 3.2%), and waist circumference (99.3 ± 9.4 vs. 94.1 ± 8.8 cm), while the fat-free mass was augmented (59.9 ± 2.9 vs. 60.7 ± 3.1 kg). Moreover, blood glucose reduced (113.5 ± 29.6 vs. 107.3 ± 28.9 mg/dL) along with high-density lipoprotein (54.6 ± 18.1 vs. 59.0 ± 18.8 mg/dL), TSH (2.1 ± 1.1 vs. 2.6 ± 1.2 mIU/mL), and free T4 (0.9 ± 0.1 vs. 1.12 ± 0.2 ng/dL) increase after physical exercise training. Plasma 8-isoprostane levels (17.24 ± 7.9 vs. 29.11 ± 17.44 pg/mL) and DNA damage (34.16 ± 7.1 vs. 45.96 ± 5.8% DNA in tail) were also higher after physical training. No changes were observed in chromosomal damage levels. These results suggest that 16 weeks of combined exercise training 3 times per week is effective in reducing body fat but also increases oxidative stress and DNA damage in obese women.

Association of Body Mass Index With Somatic Mutations in Breast Cancer

Background

The relationship between body mass index (BMI) and the prognosis or treatment response in patients with breast cancer has been demonstrated in previous studies, but the somatic mutation profiles in breast cancer patients with different BMIs have not been explored.

Methods

In the present study, the somatic mutation profiles in 421 female breast cancer patients who were stratified into three subgroups based on BMI (normal weight, overweight/obese, and underweight) were investigated. Capture-based targeted sequencing was performed using a panel comprising 520 cancer-related genes.

Results

A total of 3547 mutations were detected in 390 genes. In breast cancer patients with different BMI statuses, the tumors exhibited high mutation frequency and burden. TP53 was the most common gene in the three groups, followed by PIK3CA, ERBB2, and CDK12. Meanwhile, the mutation hotspots in TP53 and PIK3CA were the same in the three BMI groups. More JAK1 mutations were identified in underweight patients than those in normal patients. Except for JAK1, differentially mutated genes in postmenopausal patients were completely different from those in premenopausal patients. The distribution of mutation types was significantly different among BMI groups in the postmenopausal group. Underweight patients in the postmenopausal group harbored more TP53 mutations, more amplifications, and more mutations in genes involved in the WNT signaling pathway.

Conclusions

Our next-generation sequencing (NGS)-based gene panel analysis revealed the gene expression profiles of breast cancer patients with different BMI statuses. Although genes with high mutation frequency and burden were found in different BMI groups, some subtle differences could not be ignored. JAK1 mutations might play a vital role in the progression of breast cancer in underweight patients, and this needs further analysis. Postmenopausal underweight patients with breast cancer have more aggressive characteristics, such as TP53 mutations, more amplifications, and more mutations in genes involved in the WNT signaling pathway. This study provides new evidence for understanding the characteristics of breast cancer patients with different BMIs.

Obese Adipose Tissue as a Driver of Breast Cancer Growth and Development: Update and Emerging Evidence

Obesity is an established risk factor for breast cancer growth and progression. A number of advances have been made in recent years revealing new insights into this link. Early events in breast cancer development involve the neoplastic transformation of breast epithelial cells to cancer cells. In obesity, breast adipose tissue undergoes significant hormonal and inflammatory changes that create a mitogenic microenvironment. Many factors that are produced in obesity have also been shown to promote tumorigenesis. Given that breast epithelial cells are surrounded by adipose tissue, the crosstalk between the adipose compartment and breast epithelial cells is hypothesized to be a significant player in the initiation and progression of breast cancer in individuals with excess adiposity. The present review examines this crosstalk with a focus on obese breast adipose-derived estrogen, inflammatory mediators and adipokines, and how they are mechanistically linked to breast cancer risk and growth through stimulation of oxidative stress, DNA damage, and pro-oncogenic transcriptional programs. Pharmacological and lifestyle strategies targeting these factors and their downstream effects are evaluated for feasibility and efficacy in decreasing the risk of obesity-induced breast epithelial cell transformation and consequently, breast cancer development.

Dietary Antioxidants in the Treatment of Male Infertility: Counteracting Oxidative Stress

Infertility affects about 15% of the population and male factors only are responsible for ~25-30% of cases of infertility. Currently, the etiology of suboptimal semen quality is poorly understood, and many environmental and genetic factors, including oxidative stress, have been implicated. Oxidative stress is an imbalance between the production of free radicals, or reactive oxygen species (ROS), and the capacity of the body to counteract their harmful effects through neutralization by antioxidants. The purpose of this review, by employing the joint expertise of international researchers specialized in nutrition and male fertility areas, is to update the knowledge about the reproductive consequences of excessive ROS concentrations and oxidative stress on the semen quality and Assisted Reproduction Techniques (ART) clinical outcomes, to discuss the role of antioxidants in fertility outcomes, and finally to discuss why foods and dietary patterns are more innocuous long term solution for ameliorating oxidative stress and therefore semen quality results and ART fertility outcomes. Since this is a narrative review and not a systematic/meta-analysis, the summarized information in the present study should be considered cautiously.

Exposure to Particulate PAHs on Potential Genotoxicity and Cancer Risk among School Children Living Near the Petrochemical Industry

This study aimed to assess the association of exposure to particle-bound (PM_2.5) polycyclic aromatic hydrocarbons (PAHs) with potential genotoxicity and cancer risk among children living near the petrochemical industry and comparative populations in Malaysia. PM_2.5 samples were collected using a low-volume sampler for 24 h at three primary schools located within 5 km of the industrial area and three comparative schools more than 20 km away from any industrial activity. A gas chromatography-mass spectrometer was used to determine the analysis of 16 United States Environmental Protection Agency (USEPA) priority PAHs. A total of 205 children were randomly selected to assess the DNA damage in buccal cells, employing the comet assay. Total PAHs measured in exposed and comparative schools varied, respectively, from 61.60 to 64.64 ng m^-3 and from 5.93 to 35.06 ng m^-3. The PAH emission in exposed schools was contributed mainly by traffic and industrial emissions, dependent on the source apportionment. The 95th percentiles of the incremental lifetime cancer risk estimated using Monte Carlo simulation revealed that the inhalation risk for the exposed children and comparative populations was 2.22 × 10^-6 and 2.95 × 10^-7, respectively. The degree of DNA injury was substantially more severe among the exposed children relative to the comparative community. This study reveals that higher exposure to PAHs increases the risk of genotoxic effects and cancer among children.

Maternal overnutrition before and during pregnancy induces DNA damage in male offspring: A rabbit model

Using a rabbit model, we investigated whether maternal intake of a high-fat and high-carbohydrate diet (HFCD) before and during pregnancy induces an increase in micronuclei frequency and oxidative stress in offspring during adulthood. Female rabbits received a standard diet (SD) or HFCD for two months before mating and during gestation. The offspring from both groups were nursed by foster mothers fed SD until postnatal day 35. After weaning, all the animals received SD until postnatal day 440. At postnatal day 370, the frequency of micronuclei in peripheral blood reticulocytes (MN-RETs) increased in the male offspring from HFCD-fed mothers compared with the male offspring from SD-fed mothers. Additionally, fasting serum glucose increased in the offspring from HFCD-fed mothers compared with the offspring from SD-fed mothers. At postnatal day 440, the offspring rabbits were challenged with HFCD or continued with SD for 30 days. There was an increase in MN-RET frequency in the male rabbits from HFCD-fed mothers, independent of the type of challenging diet consumed during adulthood. The challenge induced changes in serum cholesterol, LDL and HDL that were influenced by the maternal diet and offspring sex. We measured malondialdehyde in the liver of rabbits as an oxidative stress marker after diet challenge. Oxidative stress in the liver only increased in the female offspring from HFCD-fed mothers who were also challenged with this same diet. The data indicate that maternal overnutrition before and during pregnancy is able to promote different effects depending on the sex of the animals, with chromosomal instability in male offspring and oxidative stress and hypercholesterolemia in female offspring. Our data might be important in the understanding of chronic diseases that develop in adulthood due to in utero exposure to maternal diet.

Role of Omentin in Obesity Paradox in Lung Cancer

Simple Summary

Unlike other cancers, lung cancer risk is inversely associated with body mass index (BMI) with limited mechanistic understanding. Overweight and obese patients have been consistently found to respond better to therapy and show better survival. The adipose tissue—in addition to storing energy—secretes multiple unique cytokines or adipokines. Our in silico analysis reveals that a novel adipokine, omentin, is significantly and consistently downregulated in lung cancers compared to healthy lung tissue. Omentin was also found to be negatively correlated with important oncogenic transcription factors like ELK4, FOXA1 and FOXC1. Our study warrants further mechanistic studies on the role of omentin in lung cancers.

Abstract

Lung cancer remains the second-most-common cancer worldwide and is associated with the highest number of cancer-related mortality. While tobacco smoking is the most important risk factor for lung cancer, many other lifestyles and occupational factors significantly contribute. Obesity is a growing global health concern and contributes to ~30% cancer-related mortality, but unlike other lifestyle diseases, lung cancer is negatively associated with obesity. We meta-analyzed multiple case-control studies confirming increased survival and better outcomes in overweight and obese lung cancer patients. Tumor heterogeneity analysis showed significant enrichment of adipocytes and preadipocytes in normal lungs compared to lung cancers. Interestingly, one of the understudied adipokine, omentin, was significantly and consistently lower in lung neoplasms compared to normal lungs. Omentin has been examined in relation to osteoarthritis, inflammatory bowel disease, cardiovascular diseases, diabetes, chronic liver disease, psoriasis and some other cancers. Aberrant expression of omentin has been reported in solid tumors; however, little is known about its role in lung cancer. We found omentin to be consistently downregulated in lung cancers, and it exhibited a negative correlation with important transcription factors FOXA1, EN1, FOXC1 and ELK4. We, therefore, suggest that omentin may serve as a prognostic factor in lung cancer and explain the “obesity paradox” in lung cancer.

Association of telomere length and telomerase methylation with n-3 fatty acids in preschool children with obesity

BACKGROUND

Telomeres play a crucial role in cellular survival and its length is a predictor for onset of chronic non-communicable diseases. Studies on association between telomeres and obesity in children have brought discrepant results and the underlying mechanisms and influential factors are to be elucidated. This study aimed to investigate changes in telomere length and telomerase reverse transcriptase (TERT) DNA methylation, and further to determine their correlation with n-3 polyunsaturated fatty acids (PUFAs) in preschool children with obesity.

METHODS

Forty-six preschool children with obesity aged 3 to 4 years were included in the study, with equal numbers of age- and gender-matched children with normal weight as control. Leukocyte telomere length was determined by the ratio of telomeric product and single copy gene obtained using real-time qPCR. DNA methylation of TERT promoter was analyzed by bisulfite sequencing. Fatty acids in erythrocytes were measured by gas chromatography with a total of 15 fatty acids analyzed. The total saturated fatty acids (SFAs), total n-6 PUFAs, total n-3 PUFAs, and the ratio of arachidonic acid (AA) to docosahexaenoic acid (DHA) were calculated. Then the correlation between leukocyte telomere length, TERT promoter methylation and fatty acids was determined.

RESULTS

In preschool children with obesity, leukocyte telomeres were shortened and had a negative association with the body mass index. The methylated fractions in 13 of 25 CpG sites in the TERT promoter were increased by approximately 3 to 35% in the children with obesity compared to the normal weight children. Erythrocyte lauric acid and total SFAs, lenoleic acid and total n-6 PUFAs were higher, and DHA was lower in the children with obesity than those in the children with normal weight. Correlative analysis showed that leukocyte telomere length had a positive association with total SFAs and DHA, and a negative association with the AA/DHA ratio. However, no association between erythrocyte DHA and the TERT promoter methylation was found.

CONCLUSION

These data indicate that the reduced body DHA content and increased AA/DHA ratio may be associated with shortened leukocyte telomeres in child obesity, which is probably not involved in the TERT promoter methylation.

Brazil nut prevents oxidative DNA damage in type 2 diabetes patients

The Brazil nut (Bertholletia excelsa, H.B.K.) originating from the Amazon region is one of the richest known sources of selenium (Se), a micronutrient that is essential and required for optimal physiological functioning. This mineral presents several health benefits, including improvement of the redox cellular status and maintenance of genomic stability. Knowing that type 2 diabetes mellitus (T2D) is strongly linked to oxidative stress and consequently DNA damage, the aim of this study was to assess the ex vivo antioxidative effects of Se through Brazil nut consumption and its potential in preventing oxidative DNA damage induced by H₂O₂. In order to accomplish this, the Comet assay (single-cell gel electrophoresis) was used to measure DNA damage in peripheral blood cells harvested before and after supplementation with Brazil nut. Comet assay was also applied ex vivo to measure the potential of Se to prevent oxidative damage to DNA induced by H₂O₂ in blood of type 2 diabetes patients collected before and after six months of supplementation with Brazil nut. We found that supplementation with Brazil nuts significantly increased serum Se levels. Furthermore, we observed a significant increase in fasting blood glucose after six months of consuming Brazil nuts; however, no significant effect was observed on the levels of glycated hemoglobin. Finally, we noticed that the cells were more resistant to H₂O₂-induced DNA damage after six months of supplementation with Brazil nut. Thus, consumption of Brazil nuts could decrease oxidative DNA damage in T2D patients, probably through the antioxidative effects of Se.