Obesity-associated non-oxidative genotoxic stress alters trophoblast turnover in human first trimester placentas.

Placental growth is most rapid during the first trimester (FT) of pregnancy, making it vulnerable to metabolic and endocrine influences. Obesity, with its inflammatory and oxidative stress, can cause cellular damage. We hypothesized that maternal obesity increases DNA damage in the FT placenta, affecting DNA damage response and trophoblast turnover. Examining placental tissue from lean and obese non-smoking women (4-12 gestational weeks), we observed higher overall DNA damage in obesity (COMET assay). Specifically, DNA double-strand breaks were found in villous cytotrophoblasts (vCTB; semi-quantitative γH2AX immunostaining), while oxidative DNA modifications (8-OHdG; FPG-COMET assay) were absent. Increased DNA damage in obese FT placentas did not correlate with enhanced DNA damage sensing and repair. Indeed, obesity led to reduced expression of multiple DNA repair genes (mRNA array), which were further shown to be influenced by inflammation through in vitro experiments using TNFα treatment on FT chorionic villous explants. Tissue changes included elevated vCTB apoptosis (TUNEL assay; caspase-cleaved cytokeratin 18), but unchanged senescence (p16) and reduced proliferation (Ki67) of vCTB, the main driver of FT placental growth. Overall, obesity is linked to heightened non-oxidative DNA damage in FT placentas, negatively affecting trophoblast growth and potentially leading to temporary reduction in early fetal growth.

Genotoxicity of selected cannabinoids in human lymphoblastoid TK6 cells.

Natural non-psychoactive cannabinoids such as cannabigerol (CBG), cannabidiol (CBD), cannabichromene (CBC), cannabidivarin (CBDV), and cannabinol (CBN) are increasingly consumed as constituents of dietary products because of the health benefits claims. Cannabinoids may reduce certain types of pain, nausea, and anxiety. Anti-inflammatory and even anti-carcinogenic properties have been discussed. However, there are insufficient data available regarding their potential (geno-)toxic effects. Therefore, we tested CBG, CBD, CBC, CBDV, and CBN for their genotoxic potential and effects on mitosis and cell cycle in human lymphoblastoid TK6 cells. The selected cannabinoids (except CBDV) induced increased micronuclei formation, which was reduced with the addition of a metabolic activation system (S9 mix). CBDV induced micronuclei only after metabolic activation. Mitotic disturbances were observed with all tested cannabinoids, while G1 phase accumulation of cells was observed for CBG, CBD and CBDV. The genotoxic effects occurred at about 1000-fold higher concentrations than are reported as blood levels from human consumption. However, the results clearly indicate a need for further research into the genotoxic effects of cannabinoids. The mechanism of the mitotic disturbance, the shape of the dose-response curves and the possible effects of mixtures of cannabinoids are aspects which need clarification.

The Comet Assay as a Tool in Human Biomonitoring Studies of Environmental and Occupational Exposure to Chemicals-A Systematic Scoping Review.

Biomonitoring of human populations exposed to chemical substances that can act as potential mutagens or carcinogens, may enable the detection of damage and early disease prevention. In recent years, the comet assay has become an important tool for assessing DNA damage, both in environmental and occupational exposure contexts. To evidence the role of the comet assay in human biomonitoring, we have analysed original research studies of environmental or occupational exposure that used the comet assay in their assessments, following the PRISMA-ScR method (preferred reporting items for systematic reviews and meta-analyses extension for scoping reviews). Groups of chemicals were designated according to a broad classification, and the results obtained from over 300 original studies (n = 123 on air pollutants, n = 14 on anaesthetics, n = 18 on antineoplastic drugs, n = 57 on heavy metals, n = 59 on pesticides, and n = 49 on solvents) showed overall higher values of DNA strand breaks in the exposed subjects in comparison with the unexposed. In summary, our systematic scoping review strengthens the relevance of the use of the comet assay in assessing DNA damage in human biomonitoring studies.

The ameliorative effect of rosmarinic acid and epigallocatechin gallate against doxorubicin-induced genotoxicity.

Doxorubicin (Dox), an effective anticancer agent, is known for its genotoxic effects on normal cells. Phenolic compounds, renowned for their antitumor, antioxidant, and antigenotoxic properties, have gained prominence in recent years. This study investigates the individual and combined protective effects of rosmarinic acid (RA) and epigallocatechin gallate (EGCG) against Dox-induced genotoxicity using various in vitro test systems. The synergistic/antagonistic interaction of these combinations on Dox's chemotherapeutic effect is explored in breast cancer cell lines. Both RA and EGCG significantly mitigate Dox-induced genotoxicity in comet, micronucleus, and Ames assays. While Dox exhibits higher selectivity against MCF-7 cells, EGCG and RA show greater selectivity against MDA-MB-231 cells. The coefficient of drug interaction reveals a synergistic effect when RA or EGCG is combined with Dox in breast cancer cells. In conclusion, both EGCG and RA effectively reduce Dox-induced genetic damage and enhance Dox's cell viability-reducing effect in breast cancer cells.

Rosmarinic acid (RA) showed protective effect against doxorubicin-induced genotoxicity.Epigallocatechin gallate (EGCG) demonstrated pro-oxidant properties at high concentrations.EGCG and RA selectively targeted MDA-MB-231 cells.Synergistic effect was observed when EGCG or RA was administered together with Dox on breast cancer cells.

Maternal Smoking in the First Trimester and its Consequence on the Early Placenta.

Smoking during pregnancy increases the risk of adverse pregnancy outcomes, such as stillbirth and fetal growth restriction. This suggests impaired placental function and restricted nutrient and oxygen supply. Studies investigating placental tissue at the end of pregnancy have revealed increased DNA damage as a potential underlying cause, which is driven by various toxic smoke ingredients and oxidative stress induced by reactive oxygen species (ROS). However, in the first trimester, the placenta develops and differentiates, and many pregnancy pathologies associated with reduced placental function originate here. Therefore, we determined DNA damage in a cohort of first-trimester placental samples of verified smokers and nonsmokers. In fact, we observed an 80% increase in DNA breaks (P < .001) and shortened telomeres by 5.8% (P = .04) in placentas exposed to maternal smoking. Surprisingly, there was a decrease in ROS-mediated DNA damage, ie, 8-oxo-guanidine modifications, in placentas of the smoking group (-41%; P = .021), which paralleled the reduced expression of base excision DNA repair machinery, which restores oxidative DNA damage. Moreover, we observed that the increase in placental oxidant defense machinery expression, which usually occurs at the end of the first trimester in a healthy pregnancy as a result of the full onset of uteroplacental blood flow, was absent in the smoking group. Therefore, in early pregnancy, maternal smoking causes placental DNA damage, contributing to placental malfunction and increased risk of stillbirth and fetal growth restriction in pregnant women. Additionally, reduced ROS-mediated DNA damage along with no increase in antioxidant enzymes suggests a delay in the establishment of physiological uteroplacental blood flow at the end of the first trimester, which may further add to a disturbed placental development and function as a result of smoking in pregnancy.

Genotoxicity of pyrrolizidine alkaloids in metabolically inactive human cervical cancer HeLa cells co-cultured with human hepatoma HepG2 cells.

Pyrrolizidine alkaloids (PAs) are secondary plant metabolites, which can be found as contaminant in various foods and herbal products. Several PAs can cause hepatotoxicity and liver cancer via damaging hepatic sinusoidal endothelial cells (HSECs) after hepatic metabolization. HSECs themselves do not express the required metabolic enzymes for activation of PAs. Here we applied a co-culture model to mimic the in vivo hepatic environment and to study PA-induced effects on not metabolically active neighbour cells. In this co-culture model, bioactivation of PA was enabled by metabolically capable human hepatoma cells HepG2, which excrete the toxic and mutagenic pyrrole metabolites. The human cervical epithelial HeLa cells tagged with H2B-GFP were utilized as non-metabolically active neighbours because they can be identified easily based on their green fluorescence in the co-culture. The PAs europine, riddelliine and lasiocarpine induced micronuclei in HepG2 cells, and in HeLa H2B-GFP cells co-cultured with HepG2 cells, but not in HeLa H2B-GFP cells cultured alone. Metabolic inhibition of cytochrome P450 enzymes with ketoconazole abrogated micronucleus formation. The efflux transporter inhibitors verapamil and benzbromarone reduced micronucleus formation in the co-culture model. Furthermore, mitotic disturbances as an additional genotoxic mechanism of action were observed in HepG2 cells and in HeLa H2B-GFP cells co-cultured with HepG2 cells, but not in HeLa H2B-GFP cells cultured alone. Overall, we were able to show that PAs were activated by HepG2 cells and the metabolites induced genomic damage in co-cultured HeLa cells.

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.

Short- and long-term reproducibility of the COMET assay for measuring DNA damage biomarkers in frozen blood samples of the EPIC-Heidelberg cohort.

The comet assay is widely used for quantification of genomic damage in humans. Peripheral blood derived mononuclear cells (PBMCs) are the most often used cell type for this purpose. Since the comet assay can be performed in an enhanced throughput format, it can be applied to large sample collections such as biobanks. The European Prospective Investigation into Cancer and Nutrition (EPIC) study is one of the largest existing prospective cohort studies, and the German Cancer Research Institute (DKFZ) in Heidelberg is a participating center with 25.000 frozen blood samples stored from around 25 years ago, enabling retrospective assessment of disease risk factors. However, experience with decades long frozen samples in the comet assay is so far missing. In Heidelberg, 800 study participants were re-invited twice between 2010 and 2012 to donate further blood samples. Here, we analyzed 299 Heidelberg-EPIC samples, compiled from frozen PBMC and buffy coat preparations selected from the different sampling time points. In addition, 47 frozen PBMC samples from morbidly obese individuals were included. For buffy coat samples, we observed a poor correlation between DNA damage in the same donors assessed at two sampling time points. Additionally, no correlation between DNA damage in buffy coat samples and PBMCs was found. For PBMCs, a good correlation was observed between samples of the same donors at the two time points. DNA damage was not affected by age and smoking status, but high BMI (>30; obesity) was associated with increased DNA damage in PBMCs. There was no indication for a threshold of a certain BMI for increased DNA damage. In conclusion, while 25 year-long stored buffy coat preparations may require adaptation of certain experimental parameters such as cell density and electrophoresis conditions, frozen PBMC biobank samples can be analyzed in the comet assay even after a decade of storage.

Cytotoxic and genotoxic properties of artathomsonine, a new oxoberberine alkaloid from Artabotrys thomsonii (annonaceae).

A phytochemical investigation of the liana of Artabotrys thomsonii led to the isolation of a new oxoberberine alkaloid, 2,10-dihydroxy-3,9-dimethoxy-8-oxo-protoberberine (7), along with six known compounds. Their chemical structures were elucidated by 1 D and 2 D NMR spectroscopic methods and HRESI-MSn data analysis. Compounds 4 and 7 were selected for further in vitro investigations. In accordance with expectations from their chemical structures, compounds 7 and 4 showed a clear antioxidant activity in a cell-free assay, with compound 7 being 7-fold more active than 4. Cytotoxicity, cytostatic and genotoxic effects only occurred at high micromolar concentrations of 50 µM or more. Compound 7 was slightly less effective than compound 4. A low micromolar concentration of 10 µM did not cause any damaging cellular effects but showed potential for a protection against the micronucleus-inducing effect of reactive oxygen species hydrogen peroxide, although not to a significant extent.

Cell survival after DNA damage in the comet assay.

The comet assay is widely used in basic research, genotoxicity testing, and human biomonitoring. However, interpretation of the comet assay data might benefit from a better understanding of the future fate of a cell with DNA damage. DNA damage is in principle repairable, or if extensive, can lead to cell death. Here, we have correlated the maximally induced DNA damage with three test substances in TK6 cells with the survival of the cells. For this, we selected hydrogen peroxide (H2O2) as an oxidizing agent, methyl methanesulfonate (MMS) as an alkylating agent and etoposide as a topoisomerase II inhibitor. We measured cell viability, cell proliferation, apoptosis, and micronucleus frequency on the following day, in the same cell culture, which had been analyzed in the comet assay. After treatment, a concentration dependent increase in DNA damage and in the percentage of non-vital and apoptotic cells was found for each substance. Values greater than 20-30% DNA in tail caused the death of more than 50% of the cells, with etoposide causing slightly more cell death than H2O2 or MMS. Despite that, cells seemed to repair of at least some DNA damage within few hours after substance removal. Overall, the reduction of DNA damage over time is due to both DNA repair and death of heavily damaged cells. We recommend that in experiments with induction of DNA damage of more than 20% DNA in tail, survival data for the cells are provided.

Genotoxicity of selected pyrrolizidine alkaloids in human hepatoma cell lines HepG2 and Huh6.

INTRODUCTION: Pyrrolizidine alkaloids (PAs) are found in many plant species as secondary metabolites which affect humans via contaminated food sources, herbal medicines and dietary supplements. Hundreds of compounds belonging to PAs have been identified. PAs undergo hepatic metabolism, after which they can induce hepatotoxicity and carcinogenicity. Many aspects of their mechanism of carcinogenicity are still unclear and it is important for human risk assessment to investigate this class of compounds further. MATERIAL AND METHODS: Human hepatoma cells HepG2 were used to investigate the genotoxicity of different chemical structural classes of PAs, namely europine, lycopsamine, retrorsine, riddelliine, seneciphylline, echimidine and lasiocarpine, in the cytokinesis-block micronucleus (CBMN) assay. The different ester type PAs europine, seneciphylline, and lasiocarpine were also tested in human hepatoma Huh6 cells. Six different PAs were investigated in a crosslink comet assay in HepG2 cells. RESULTS: The maximal increase of micronucleus formation was for all PAs in the range of 1.64-2.0 fold. The lowest concentrations at which significant induction of micronuclei were found were 3.2 µM for lasiocarpine and riddelliine, 32 µM for retrorsine and echimidine, and 100 µM for seneciphylline, europine and lycopsamine. Significant induction of micronuclei by lasiocarpine, seneciphylline, and europine were achieved in Huh6 cells at similar concentrations. Reduced tail formation after hydrogen peroxide treatment was found in the crosslink comet assay for all diester type PAs, while an equimolar concentration of the monoesters europine and lycopsamine did not significantly reduce DNA migration. CONCLUSION: The widely available human hepatoma cell lines HepG2 and Huh6 were suitable for the assessment of PA-induced genotoxicity. Selected PAs confirmed previously published potency rankings in the micronucleus assay. In HepG2 cells, the crosslinking activity was related to the ester type, which is a first report of PA mediated effects in the comet assay.

Simulating the Post-gastric Bypass Intestinal Microenvironment Uncovers a Barrier-Stabilizing Role for FXR.

Regional changes to the intestinal microenvironment brought about by Roux-en-Y gastric bypass (RYGB) surgery may contribute to some of its potent systemic metabolic benefits through favorably regulating various local cellular processes. Here, we show that the intestinal contents of RYGB-operated compared with sham-operated rats region-dependently confer superior glycemic control to recipient germ-free mice in association with suppression of endotoxemia. Correspondingly, they had direct barrier-stabilizing effects on an intestinal epithelial cell line which, bile-exposed intestinal contents, were partly farnesoid X receptor (FXR)-dependent. Further, circulating fibroblast growth factor 19 levels, a readout of intestinal FXR activation, negatively correlated with endotoxemia severity in longitudinal cohort of RYGB patients. These findings suggest that various host- and/or microbiota-derived luminal factors region-specifically and synergistically stabilize the intestinal epithelial barrier following RYGB through FXR signaling, which could potentially be leveraged to better treat endotoxemia-induced insulin resistance in obesity in a non-invasive and more targeted manner.

Micronucleus frequency in chronic kidney disease patients: A review.

BACKGROUND: Chronic kidney disease (CKD) is defined as a gradual loss of renal function progressing from very mild damage, with no obvious symptoms in stage one, to complete kidney failure in stage five, which ultimately requires kidney replacement therapy by organ transplantation or dialysis. Cancer incidence and other health problems, mainly diabetes and hypertension, are elevated in CKD, ultimately leading to elevated mortality. METHODS: A literature search on the induction of micronuclei (MN) as endpoint for genomic damage in white blood cells and buccal mucosa cells of CKD patients was conducted. Possible associations with disease stage, treatment modalities, and vitamin or antioxidant supplementations were analyzed. RESULTS: In total, 26 studies were enclosed in the data analysis. Patient groups in the predialysis or hemodialysis state of the disease exhibit higher levels of genomic damage, measured as micronucleus frequency in peripheral blood lymphocytes and buccal mucosa cells, than healthy control groups. Genomic damage seems to increase with the disease stage during the predialysis phase. The association with dialysis regimens or with years on dialysis is less clear, but there are indications that efficient removal of uremic toxins is beneficial. Patients with CKD receive a variety of medications, some of which could modulate genomic damage levels and thus contribute to the observed heterogeneity. In addition, supplementation with vitamins or antioxidants may in some cases lower the genomic damage. Meta-Analysis confirmed the high and significant levels of genomic damage present in CKD patients compared to matched healthy controls. CONCLUSION: Genomic damage, as measured by the MN frequency, is elevated in CKD patients. Different strategies, including supplementation with antioxidants and optimizing dialysis processes, can reduce the levels of genomic damage and the different associated pathologies. Whether MN frequency can in the future also be used to assist in certain therapeutic decisions in CKD will have to be investigated further in larger studies.

Influence of bariatric surgery induced weight loss on oxidative DNA damage.

Obesity is associated with elevated cancer risk, which may be represented by elevated genomic damage. Oxidative stress plays a key role in obesity related detrimental health consequences including DNA oxidation damage. The elevated cancer risk in obesity may be a consequence. Weight loss has been shown to reduce genomic damage, but the role of oxidative stress in that has not been clarified. The aim of this study is therefore to investigate the influence of bariatric surgery induced weight loss on DNA oxidation damage in morbidly obese subjects. For this aim, we used cryopreserved peripheral blood mononuclear cells in the FPG comet assay. Advanced protein oxidation products and 3-nitrotyrosine were measured as oxidative and nitrative protein stress markers. Furthermore, expression of oxidative stress related proteins HSP70 and Nrf2 as well as mitochondrial enzyme citrate synthase and NADPH oxidase subunit p22 phox were analysed. Our findings revealed significantly reduced DNA strand breaks, but DNA base oxidation was not reduced. We observed significant reduction in plasma AOPPs and 3-nitrotyrosine, which indicated an improvement in oxidative/nitrative stress. However, expression of HSP70 and Nrf2 were not altered after weight loss. In addition, expression of citrate synthase and p22 phox were also unaltered. Overall, bariatric surgery induced significant reduction in excess body weight and improved the patients' health status, including reduced DNA strand breaks and slightly improved antioxidant status in some of the investigated endpoints, while cellular ROS formation and DNA oxidation damage stayed unaltered. This complex situation may be due to combined beneficial effects of weight loss and burdening of the body with fat breakdown products. In the future, collecting samples two years after surgery, when patients have been in a weight plateau for some time, might be a promising approach.

Overlapping mechanism of the induction of genomic damage by insulin and adrenaline in human promyelocytic HL-60 cells.

Endogenous hormones systemically regulate the growth and metabolism and some prior studies have shown that their imbalance can have a potential to induce genomic damage in in vitro and animal models. Some conditions that are associated with elevated levels of endogenous hormones are hyperinsulinemia and intense exercise-induced stress causing increased adrenaline. In this study we test whether these two hormones, could cause an additive increase in genomic damage and whether they have an overlapping mechanism of action. For this, we use the human promyelocytic HL60 cells, as they express the receptors for both hormones. At doses taken from the saturation level of the individual dose response curves, no additivity in genomic damage was detected through micronucleus induction. This hints towards a common step in the pathway, which is under these conditions fully activated by each of the individual hormone. To investigate this further, individual and common parts in insulin and adrenaline signalling such as their respective hormone receptors, the downstream protein AKT and the involvement of mitochondria and NADPH oxidase (NOX) enzymes were studied. The results indicate no additive effect of high hormone concentrations in genomic damage in the in vitro model, which may be due to exhaustion of the NOX 2-mediated reactive oxygen production. It remains to be determined whether a similar situation may occur in in vivo situations.

Potassium bromate as positive assay control for the Fpg-modified comet assay.

The comet assay is a popular assay in biomonitoring studies. DNA strand breaks (or unspecific DNA lesions) are measured using the standard comet assay. Oxidative stress-generated DNA lesions can be measured by employing DNA repair enzymes to recognise oxidatively damaged DNA. Unfortunately, there has been a tendency to fail to report results from assay controls (or maybe even not to employ assay controls). We believe this might have been due to uncertainty as to what really constitutes a positive control. It should go without saying that a biomonitoring study cannot have a positive control group as it is unethical to expose healthy humans to DNA damaging (and thus potentially carcinogenic) agents. However, it is possible to include assay controls in the analysis (here meant as a cryopreserved sample of cells i.e. included in each experiment as a reference sample). In the present report we tested potassium bromate (KBrO3) as a positive comet assay control for the formamidopyrimidine DNA glycosylase (Fpg)-modified comet assay. Ten laboratories used the same procedure for treatment of monocytic THP-1 cells with KBrO3 (0.5, 1.5 and 4.5 mM for 1 h at 37°C) and subsequent cryopreservation. Results from one laboratory were excluded in the statistical analysis because of technical issues in the Fpg-modified comet assay. All other laboratories found a concentration-response relationship in cryopreserved samples (regression coefficients from 0.80 to 0.98), although with different slopes ranging from 1.25 to 11.9 Fpg-sensitive sites (%DNA in tail) per 1 mM KBrO3. Our results demonstrate that KBrO3 is a suitable positive comet assay control.

Differentiated and exponentially growing HL60 cells exhibit different sensitivity to some genotoxic agents in the comet assay.

The aim of this study was to investigate the effect of the cell differentiation status on the sensitivity to genotoxic insults. For this, we utilized the comet assay to test the DNA damage after treatment with 5 different substances with different mechanism of action in human promyelocytic HL60 cells with or without cell differentiation. A 4-hour MMS treatment induced a significant and concentration-dependent increase in DNA damage for both differentiated and undifferentiated cells, but the difference in sensitivity was only significant at the highest concentration. A 4-hour doxorubicin treatment did not induce DNA damage in differentiated HL60 cells, while it did in undifferentiated cells with its highest tested concentration. A one-hour etoposide treatment caused significant increase in DNA damage concentration dependently in both cell variants. This DNA damage was significantly higher in undifferentiated HL60 cells with several tested concentrations of etoposide. The treatment with the oxidizing substances hydrogen peroxide and potassium bromate yielded significant DNA damage induction in both undifferentiated and differentiated cells with no difference according to the differentiation status. Doxorubicin and etoposide are known to inhibit topoisomerase II. The activity of this enzyme has been shown to be higher in undifferentiated actively proliferating cells than in differentiated cells. This may be of relevance when exposures to topoisomerase-inhibiting compounds or the genotoxicity of compounds with unknown mechanism of action are assessed in routine testing.

A systematic review of the use of the alkaline comet assay for genotoxicity studies in human colon-derived cells.

This review describes the use of the comet assay for assessment of DNA damage in human colon cells. We screened 98 papers, which employed human colon -derived cells to analyse DNA damage induced by different insults with the comet assay. In most cases tumour cell lines were used, and only a few studies were performed with primary colon cells. The comet assay was mostly applied to test chemotherapeutics and natural products. We could not find a clear difference between the susceptibility of cell lines to genotoxic insults and they were all suitable for comet assay experiments. Further comparisons between cell lines, and with primary cells and stem cells would be desirable to understand the relevance of the established cell lines as model for the human target tissue better.

Protective effects of tricetinidin against oxidative stress inducers in rat kidney cells: A comparison with delphinidin and standard antioxidants.

The potential protective effect of tricetinidin as novel antioxidant is investigated and compared with selected known antioxidant substances in vitro. Dihydroethidium staining was performed to detect intracellular ROS formation and the protective effect of the antioxidant substances in combination with the superoxide-inducer antimycin a (AMA). Glutathione level, mitochondrial membrane potential and HO-1 expression were analysed for further characterization of the cellular response. The cytokinesis block micronucleus test was applied to investigate the anti-genotoxic effect of the substances against insulin induced genomic damage. AMA treatment caused a significant increase in intracellular ROS formation and insulin treatment induced a significant micronucleus induction in NRK cells. Combination of the antioxidant substances with AMA or insulin protected from the oxidative stress and the micronucleus-induction. All analysed antioxidants showed comparable effects on GSH production and mitochondrial membrane potential. Only delphinidin and tricetinidin caused an increase in HO-1 expression. Tricetinidin and delphinidin might be good candidates for development as an antioxidant supplement. Further research is necessary to show possible therapeutic and preventive effects of tricetinidin and delphinidin in vivo.

Decreased Chromosomal Damage in Lymphocytes of Obese Patients After Bariatric Surgery.

The number of bariatric surgeries being performed worldwide has markedly risen. While the improvement in obesity-associated comorbidities after bariatric surgery is well-established, very little is known about its impact on cancer risk. The peripheral lymphocyte micronucleus test is a widely used method for the monitoring of chromosomal damage levels in vivo, and micronucleus frequency positively correlates with cancer risk. Therefore, the aim of this study was to compare the micronucleus frequency before and after bariatric surgery in obese subjects. Peripheral blood mononuclear cells were collected from 45 obese subjects before and at two time-points after bariatric surgery (6 and 12 months) to assess spontaneous micronucleus frequency. Consistent with the increased cancer risk previously shown, bariatric surgery-induced weight loss led to a significant reduction in lymphocyte micronucleus frequency after 12 months. Interestingly, comorbidities such as type 2 diabetes mellitus and metabolic syndrome further seemed to have an impact on the lymphocyte micronucleus frequency. Our findings may indicate a successful reduction of cancer risk in patients following weight loss caused by bariatric surgery.