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1.  Sex-specific effects of dietary fatty acids on saliva cortisol and social behavior in guinea pigs under different social environmental conditions 
Unbalanced dietary intakes of saturated (SFAs) and polyunsaturated (PUFAs) fatty acids can profoundly influence the hypothalamic-pituitary-adrenal (HPA)-axis and glucocorticoid secretions in relation to behavioral performances. The beneficial effects of higher dietary PUFA intakes and PUFA:SFA ratios may also affect social interactions and social-living per se, where adequate physiological and behavioral responses are essential to cope with unstable social environmental conditions.
Effects of diets high in PUFAs or SFAs and a control diet were investigated in male and female guinea pigs after 60 days of supplementation. Plasma fatty acid patterns served as an indicator of the general fatty acid status. HPA-axis activities, determined by measuring saliva cortisol concentrations, social behaviors, and hierarchy ranks were analyzed during group housing of established single-sexed groups and during challenging social confrontations with unfamiliar individuals of the other groups.
The plasma PUFA:SFA ratio was highest in PUFA supplemented animals, with female levels significantly exceeding males, and lowest in SFA animals. SFA males and females showed increased saliva cortisol levels and decreased aggressiveness during group housing, while sociopositive behaviors were lowest in PUFA males. Males generally showed higher cortisol increases in response to the challenging social confrontations with unfamiliar individuals than females. While increasing cortisol concentrations were detected in control and PUFA animals, no such effect was found in SFA animals. During social confrontations, PUFA males showed higher levels of agonistic and sociopositive behaviors and also gained higher dominance ranks among males, which was not detected for females.
While SFAs seemingly impaired cortisol responses and social behaviors, PUFAs enabled adequate behavioral responses in male individuals under stressful new social environmental conditions. This sex-specific effect was possibly related to a general sex difference in the n-3 PUFA bioavailability and cortisol responses, which may indicate that males are more susceptible to changing environmental conditions, and shows how dietary fatty acids can shape social systems.
Electronic supplementary material
The online version of this article (doi:10.1186/s13293-016-0107-5) contains supplementary material, which is available to authorized users.
PMCID: PMC5034672  PMID: 27688870
Polyunsaturated fatty acid; Saturated fatty acid; Saliva cortisol concentrations; Social confrontations; Social behavior; Social hierarchy
2.  Oxidative Stress, DNA Damage and DNA Repair in Female Patients with Diabetes Mellitus Type 2 
PLoS ONE  2016;11(9):e0162082.
Diabetes mellitus type 2 (T2DM) is associated with oxidative stress which in turn can lead to DNA damage. The aim of the present study was to analyze oxidative stress, DNA damage and DNA repair in regard to hyperglycemic state and diabetes duration.
Female T2DM patients (n = 146) were enrolled in the MIKRODIAB study and allocated in two groups regarding their glycated hemoglobin (HbA1c) level (HbA1c≤7.5%, n = 74; HbA1c>7.5%, n = 72). In addition, tertiles according to diabetes duration (DD) were created (DDI = 6.94±3.1 y, n = 49; DDII = 13.35±1.1 y, n = 48; DDIII = 22.90±7.3 y, n = 49). Oxidative stress parameters, including ferric reducing ability potential, malondialdehyde, oxidized and reduced glutathione, reduced thiols, oxidized LDL and F2-Isoprostane as well as the activity of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase were measured. Damage to DNA was analyzed in peripheral blood mononuclear cells and whole blood with single cell gel electrophoresis. DNA base excision repair capacity was tested with the modified comet repair assay. Additionally, mRNA expressions of nine genes related to base excision repair were analyzed in a subset of 46 matched individuals.
No significant differences in oxidative stress parameters, antioxidant enzyme activities, damage to DNA and base excision repair capacity, neither between a HbA1c cut off />7.5%, nor between diabetes duration was found. A significant up-regulation in mRNA expression was found for APEX1, LIG3 and XRCC1 in patients with >7.5% HbA1c. Additionally, we observed higher total cholesterol, LDL-cholesterol, LDL/HDL-cholesterol, triglycerides, Framingham risk score, systolic blood pressure, BMI and lower HDL-cholesterol in the hyperglycemic group.
BMI, blood pressure and blood lipid status were worse in hyperglycemic individuals. However, no major disparities regarding oxidative stress, damage to DNA and DNA repair were present which might be due to good medical treatment with regular health checks in T2DM patients in Austria.
PMCID: PMC5012603  PMID: 27598300
3.  Elastic band resistance training influences transforming growth factor-ß receptor I mRNA expression in peripheral mononuclear cells of institutionalised older adults: the Vienna Active Ageing Study (VAAS) 
Ageing, inactivity and obesity are associated with chronic low-grade inflammation contributing to a variety of lifestyle-related diseases. Transforming growth factor-β (TGF-β) is a multimodal protein with various cellular functions ranging from tissue remodelling to the regulation of inflammation and immune functions. While it is generally accepted that aerobic exercise exerts beneficial effects on several aspects of immune functions, even in older adults, the effect of resistance training remains unclear. The aim of this study was to investigate whether progressive resistance training (6 months) with or without nutritional supplementation (protein and vitamins) would influence circulating C-reactive protein and TGF-β levels as well as TGF-β signalling in peripheral mononuclear cells (PBMCs) of institutionalised adults with a median age of 84.5 (65.0–97.4) years.
Elastic band resistance training significantly improved performance as shown by the arm-lifting test (p = 0.007), chair stand test (p = 0.001) and 6-min walking test (p = 0.026). These results were paralleled by a reduction in TGF-β receptor I (TGF-βRI) mRNA expression in PBMCs (p = 0.006), while circulating inflammatory markers were unaffected. Protein and vitamin supplementation did not provoke any additional effects. Interestingly, muscular endurance of upper and lower body and aerobic performance at baseline were negatively associated with changes in circulating TGF-β at the early phase of the study. Furthermore, drop-outs of the study were characterised not only by lower physical performance but also higher TGF-β and TGF-βRI mRNA expression, and lower miRNA-21 expression.
Progressive resistance training with elastic bands did not influence chronic low-grade inflammation but potentially affected TGF-β signalling in PBMCs through altered TGF-βRI mRNA expression. There appears to be an association between physical performance and TGF-β expression in PBMCs of older adults, in which the exact mechanisms need to be clarified.
PMCID: PMC4929754  PMID: 27375767
Vienna Active Ageing Study (VAAS); TGF-β pathway; microRNA; Chronic inflammation; Inflammageing; Strength training
4.  Biomarkers of Aging: From Function to Molecular Biology 
Nutrients  2016;8(6):338.
Aging is a major risk factor for most chronic diseases and functional impairments. Within a homogeneous age sample there is a considerable variation in the extent of disease and functional impairment risk, revealing a need for valid biomarkers to aid in characterizing the complex aging processes. The identification of biomarkers is further complicated by the diversity of biological living situations, lifestyle activities and medical treatments. Thus, there has been no identification of a single biomarker or gold standard tool that can monitor successful or healthy aging. Within this short review the current knowledge of putative biomarkers is presented, focusing on their application to the major physiological mechanisms affected by the aging process including physical capability, nutritional status, body composition, endocrine and immune function. This review emphasizes molecular and DNA-based biomarkers, as well as recent advances in other biomarkers such as microRNAs, bilirubin or advanced glycation end products.
PMCID: PMC4924179  PMID: 27271660
aging; biomarker; physical function; inflammaging; DNA based marker; molecular marker; miRNA
5.  Vitamin and antioxidant rich diet increases MLH1 promoter DNA methylation in DMT2 subjects 
Clinical Epigenetics  2012;4(1):19.
Oxidative stress may lead to an increased level of unrepaired cellular DNA damage, which is discussed as one risk for tumor initiation. Mismatch repair (MMR) enzymes act as proofreading complexes that maintain the genomic integrity and MMR-deficient cells show an increased mutation rate. One important gene in the MMR complex is the MutL homolog 1 (MLH1) gene. Since a diet rich in antioxidants has the potential to counteract harmful effects by reactive oxygen species (ROS), we investigated the impact of an antioxidant, folate, and vitamin rich diet on the epigenetic pattern of MLH1. These effects were analyzed in individuals with non-insulin depended diabetes mellitus type 2 (NIDDM2) and impaired fasting glucose (IFG).
In this post-hoc analysis of a randomized trial we analyzed DNA methylation of MLH1, MSH2, and MGMT at baseline and after 8 weeks of intervention, consisting of 300 g vegetables and 25 ml plant oil rich in polyunsaturated fatty acids per day. DNA methylation was quantified using combined bisulfite restriction enzyme analysis (COBRA) and pyrosequencing. MLH1 and DNMT1 mRNA expression were investigated by qRT-PCR. DNA damage was assessed by COMET assay. Student’s two-tailed paired t test and one-way ANOVA with Scheffé corrected Post hoc test was used to determine significant methylation and expression differences. Two-tailed Pearson test was used to determine correlations between methylation level, gene expression, and DNA strand break amount.
The intervention resulted in significantly higher CpG methylation in two particular MLH1 promoter regions and the MGMT promoter. DNA strand breaks and methylation levels correlated significantly. The expression of MLH1, DNMT1, and the promoter methylation of MSH2 remained stable. CpG methylation levels and gene expression did not correlate.
This vitamin and antioxidant rich diet affected the CpG methylation of MLH1. The higher methylation might be a result of the ROS scavenging antioxidant rich diet, leading to lower activity of DNA demethylating enzymes. Our results suggest the hypothesis of CpG demethylation via DNA repair enzymes under these circumstances. NIDDM2 and IFG patients benefit from this simple dietary intervention involving epigenetic and DNA repair mechanisms.
PMCID: PMC3579724  PMID: 23025454
MLH1; ROS; DNA methylation; Demethylation; Nutritional intervention; Diabetes; Antioxidant; Pyrosequencing
6.  Features of an altered AMPK metabolic pathway in Gilbert’s Syndrome, and its role in metabolic health 
Scientific Reports  2016;6:30051.
Energy metabolism, involving the ATP-dependent AMPK-PgC-Ppar pathway impacts metabolic health immensely, in that its impairment can lead to obesity, giving rise to disease. Based on observations that individuals with Gilbert’s syndrome (GS; UGT1A1*28 promoter mutation) are generally lighter, leaner and healthier than controls, specific inter-group differences in the AMPK pathway regulation were explored. Therefore, a case-control study involving 120 fasted, healthy, age- and gender matched subjects with/without GS, was conducted. By utilising intra-cellular flow cytometry (next to assessing AMPKα1 gene expression), levels of functioning proteins (phospho-AMPK α1/α2, PgC 1 α, Ppar α and γ) were measured in PBMCs (peripheral blood mononucleated cells). In GS individuals, rates of phospho-AMPK α1/α2, -Ppar α/γ and of PgC 1α were significantly higher, attesting to a boosted fasting response in this condition. In line with this finding, AMPKα1 gene expression was equal between the groups, possibly stressing the post-translational importance of boosted fasting effects in GS. In reflection of an apparently improved health status, GS individuals had significantly lower BMI, glucose, insulin, C-peptide and triglyceride levels. Herewith, we propose a new theory to explain why individuals having GS are leaner and healthier, and are therefore less likely to contract metabolic diseases or die prematurely thereof.
PMCID: PMC4956769  PMID: 27444220
7.  Longer telomeres in chronic, moderate, unconjugated hyperbilirubinaemia: insights from a human study on Gilbert’s Syndrome 
Scientific Reports  2016;6:22300.
Bilirubin (BR) is a natural endogenous compound with a potent bioactivity. Gilbert’s Syndrome (GS) is a benign hereditary condition of increased unconjugated bilirubin (UCB) in serum and serves as a convenient model for studying the effects of BR in humans. In absence of liver disease, increased UCB levels are inversely associated to all-cause mortality risk, especially from cardiovascular diseases (CVDs). On the other hand, telomere malfunction is linked to a higher risk of CVDs. To our knowledge, there is no data on whether UCB is linked to telomere length in healthy or diseased individuals In the present study we have observed a relationship between mildly increased serum UCB and telomere length. We used an in vivo approach, assessing telomere length in PBMCs from individuals with GS (n = 60) and matched healthy controls (n = 60). An occurrence of longer telomeres was observed in male individuals chronically exposed to increased UCB, as well as in Gunn rats, an animal model of unconjugated hyperbilirubinaemia. Previously identified differences in immunomodulation and redox parameters in individuals with GS, such as IL-6, IL-1β and ferric reducing ability of plasma, were confirmed and proposed as possible contributors to the occurrence of longer telomeres in GS.
PMCID: PMC4772088  PMID: 26926838
8.  Effects of elastic band resistance training and nutritional supplementation on muscle quality and circulating muscle growth and degradation factors of institutionalized elderly women: the Vienna Active Ageing Study (VAAS) 
Regular resistance exercise training and a balanced diet may counteract the age-related muscular decline on a molecular level. The aim of this study was to investigate the influence of elastic band resistance training and nutritional supplementation on circulating muscle growth and degradation factors, physical performance and muscle quality (MQ) of institutionalized elderly.
Within the Vienna Active Ageing Study, 91 women aged 83.6 (65.0–92.2) years were randomly assigned to one of the three intervention groups (RT, resistance training; RTS, resistance training plus nutritional supplementation; CT, cognitive training). Circulating levels of myostatin, activin A, follistatin, IGF-1 and GDF-15, as well as MQ and functional parameters were tested at baseline as well as after 3 and 6 months of intervention.
MQ of lower extremities significantly increased in the RT group (+14 %) and RTS group (+12 %) after 6 months. Performance improved in the RT and RTS groups for chair stand test (RT: +18 %; RTS: +15 %). Follistatin increased only in the RT group (+18 %) in the latter phase of the intervention, accompanied by a decrease in the activin A-to-follistatin ratio (−7 %). IGF-1, myostatin and GDF-15 levels were not affected by the intervention.
Our data confirm that strength training improves physical performance and MQ even in very old institutionalized women. This amelioration appears to be mediated by blocking muscle degradation pathways via follistatin rather than inducing muscle growth through the IGF-1 pathway. As plasma levels of biomarkers reflect an overall status of various organ systems, future studies of tissue levels are suggested.
PMCID: PMC4834098  PMID: 26931422
Circulating myokines; Sarcopenia; Strength training; Ageing; Blood-based biomarkers; Essential amino acids
9.  Sex-Specific Effects of Diets High in Unsaturated Fatty Acids on Spatial Learning and Memory in Guinea Pigs 
PLoS ONE  2015;10(10):e0140485.
Unsaturated fatty acids (UFAs), including omega-3, omega-6 polyunsaturated and omega-9 monounsaturated fatty acids, are essential components and modulators of neuromembranes and may affect various aspects of physiology and cognition. UFAs are suggested to positively affect spatial learning and memory and also to diminish the negative consequences of physiological stress on cognitive abilities. Due to pronounced sex differences in neurophysiological functions, we hypothesize that these UFA-related effects might differ between male and female individuals. We therefore determined the effects of dietary UFAs on cognitive performances in a radial-Y-maze in male and female guinea pigs in relation to saliva cortisol concentrations, a marker for physiological stress. Animals were assigned to four treatment groups and maintained on diets enriched in either chia seeds (omega-3), walnuts (omega-6), or peanuts (omega-9), or a control diet. Female learning abilities throughout a three-day learning phase were positively affected by omega-3 and omega-9, as determined by a decreasing latency to pass the test and the number of conducted errors, while males generally showed distinct learning abilities, irrespective of the diet. A sex difference in learning performances was found in the control group, with males outperforming females, which was not detected in the UFA-supplemented groups. This was paralleled by significantly increased saliva cortisol concentrations in males throughout the cognition test compared to females. Three days after this learning phase, UFA-supplemented males and all females showed unchanged performances, while control males showed an increased latency and therefore an impaired performance. These results were corroborated by pronounced differences in the plasma UFA-status, corresponding to the different dietary treatments. Our findings indicate sex-specific effects of dietary UFAs, apparently enhancing spatial learning abilities only in females and protecting males from long-term memory impairment, while male learning abilities seem to be more strongly affected by an acute physiological stress response to the maze task.
PMCID: PMC4607430  PMID: 26469777
10.  Effects of Diets High in Unsaturated Fatty Acids on Socially Induced Stress Responses in Guinea Pigs 
PLoS ONE  2014;9(12):e116292.
Unsaturated fatty acids (UFAs), such as omega-3 and omega-6 poly- and omega-9 monounsaturated fatty acids are important nutrients and major components of neuronal cell membranes. They play a major role in modulating brain functions and physiology and may therefore diminish behavioral and physiological stress reactions in corroboration with decreased cortisol concentrations. Functionally, cortisol itself can modulate several behaviors and also the fatty acid metabolism in the long term. But only little is known about the behavioral and physiological influences of dietary UFAs in a social group, where individuals are regularly exposed to stressful situations. Therefore, the aim of this study was to determine the effects of dietary UFAs on saliva cortisol concentrations and behavioral responses in socially confronted guinea pigs. Three groups of animals were additionally supplemented with 500 mg chia seeds (high in omega-3), walnuts (high in omega-6), or peanuts (high in omega-9) per kg bodyweight each day and compared to a control group. During social confrontation saliva cortisol concentrations significantly increased in all groups, which was accompanied by a loss in bodyweight. However, cortisol levels remained lower in the chia and walnut groups compared to controls. Additionally, the walnut group displayed significantly increased locomotion, while no differences between groups were detected in socio-positive, sexual, or aggressive behaviors. Total plasma omega-3, omega-6, and omega-9 fatty acids were significantly increased in the corresponding groups, due to the dietary supplementations. However, a significant decrease in plasma omega-3 and an increase in plasma n-6 fatty acids were detected in the chia group when comparing the measurements before and after social confrontation. We conclude that both omega-3 and omega-6 polyunsaturated fatty acids can diminish behavioral and physiological stress responses to the social environment, enabling individuals to cope with social stressors, but at the expense of plasma derived omega-3 fatty acids.
PMCID: PMC4281161  PMID: 25551380
11.  Endogenous Tetrapyrroles Influence Leukocyte Responses to Lipopolysaccharide in Human Blood: Pre-Clinical Evidence Demonstrating the Anti-Inflammatory Potential of Biliverdin 
Sepsis is associated with abnormal host immune function in response to pathogen exposure, including endotoxin (lipopolysaccharide; LPS). Cytokines play crucial roles in the induction and resolution of inflammation in sepsis. Therefore, the primary aim of this study was to investigate the effects of endogenous tetrapyrroles, including biliverdin (BV) and unconjugated bilirubin (UCB) on LPS-induced cytokines in human blood. Biliverdin and UCB are by products of haem catabolism and have strong cytoprotective, antioxidant and anti-inflammatory effects. In the present study, whole human blood supplemented with BV and without was incubated in the presence or absence of LPS for 4 and 8 hours. Thereafter, whole blood was analysed for gene and protein expression of cytokines, including IL-1β, IL-6, TNF, IFN-γ, IL-1Ra and IL-8. Biliverdin (50 μM) significantly decreased the LPS-mediated gene expression of IL-1β, IL-6, IFN-γ, IL-1Ra and IL-8 (P<0.05). Furthermore, BV significantly decreased LPS-induced secretion of IL-1β and IL-8 (P<0.05). Serum samples from human subjects and, wild type and hyperbilirubinaemic Gunn rats were also used to assess the relationship between circulating bilirubin and cytokine expression/production. Significant positive correlations between baseline UCB concentrations in human blood and LPS-mediated gene expression of IL-1β (R=0.929), IFN-γ (R=0.809), IL-1Ra (R=0.786) and IL-8 (R=0.857) were observed in blood samples (all P<0.05). These data were supported by increased baseline IL-1β concentrations in hyperbilirubinaemic Gunn rats (P<0.05). Blood samples were also investigated for complement receptor-5 (C5aR) expression. Stimulation of blood with LPS decreased gene expression of C5aR (P<0.05). Treatment of blood with BV alone and in the presence of LPS tended to decrease C5aR expression (P=0.08). These data indicate that supplemented BV inhibits the ex vivo response of human blood to LPS. Surprisingly, however, baseline UCB was associated with heighted inflammatory response to LPS. This is the first study to explore the effects of BV in a preclinical human model of inflammation and suggests that BV could represent an anti-inflammatory target for the prevention of LPS mediated inflammation in vivo.
PMCID: PMC4145741  PMID: 25177524
Cytokine; Inflammation; Tetrapyrroles; Lipopolysaccharide
12.  Biliverdin modulates the expression of C5aR in response to endotoxin in part via mTOR signaling 
•Biliverdin mitigates LPS-dependent C5aR expression in macrophages in part via mTOR.•Biliverdin promotes phosphorylation of Akt and PS6.•Biliverdin decreases LPS-mediated induction of C5aR-associated cytokines.
Macrophages play a crucial role in the maintenance and resolution of inflammation and express a number of pro- and anti-inflammatory molecules in response to stressors. Among them, the complement receptor 5a (C5aR) plays an integral role in the development of inflammatory disorders. Biliverdin and bilirubin, products of heme catabolism, exert anti-inflammatory effects and inhibit complement activation. Here, we define the effects of biliverdin on C5aR expression in macrophages and the roles of Akt and mammalian target of rapamycin (mTOR) in these responses. Biliverdin administration inhibited lipopolysaccharide (LPS)-induced C5aR expression (without altering basal expression), an effect partially blocked by rapamycin, an inhibitor of mTOR signaling. Biliverdin also reduced LPS-dependent expression of the pro-inflammatory cytokines TNF-α and IL-6. Collectively, these data indicate that biliverdin regulates LPS-mediated expression of C5aR via the mTOR pathway, revealing an additional mechanism underlying biliverdin’s anti-inflammatory effects.
PMCID: PMC4051991  PMID: 24814708
ANOVA, analysis of variance; BCA, bicinchoninic acid; FACS, fluorescence-activated cell sorting; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; HPRT, hypoxanthine-guanine phosphoribosyltransferase; M-CSF, macrophage-colony stimulating factor; NF-κB, nuclear factor kappa B; qRT-PCR, quantitative real time polymerase chain reaction; Macrophage; Inflammation; mTOR
15.  Bilirubin and Related Tetrapyrroles Inhibit Food-Borne Mutagenesis: A Mechanism for Antigenotoxic Action against a Model Epoxide 
Journal of Natural Products  2013;76(10):1958-1965.
Bilirubin exhibits antioxidant and antimutagenic effects in vitro. Additional tetrapyrroles that are naturally abundant were tested for antigenotoxicity in Salmonella. Un-/conjugated bilirubin (1 and 2), biliverdin (4), bilirubin and biliverdin dimethyl esters (3 and 5), stercobilin (6), urobilin (7), and protoporphyrin (8) were evaluated at physiological concentrations (0.01–2 μmol/plate; 3.5–714 μM) against the metabolically activated food-borne mutagens aflatoxin B1 (9) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (10). Compound 8 most effectively inhibited the mutagenic effects of 9 in strain TA102 and 10 in TA98. Compound 7 inhibited 9-induced mutagenesis in strain TA98 most effectively, while 1 and 4 were promutagenic in this strain. This is likely due to their competition with mutagens for phase-II detoxification. Mechanistic investigations into antimutagenesis demonstrate that tetrapyrroles react efficiently with a model epoxide of 9, styrene epoxide (11), to form covalent adducts. This reaction is significantly faster than that of 11 with guanine. Hence, the evaluated tetrapyrroles inhibited genotoxicity induced by poly-/heterocyclic amines found in foods, and novel evidence obtained in the present investigation suggests this may occur via chemical scavenging of genotoxic metabolites of the mutagens investigated. This may have important ramifications for maintaining health, especially with regard to cancer prevention.
PMCID: PMC3812704  PMID: 24156291
16.  In vitro DNA-damaging effects of intestinal and related tetrapyrroles in human cancer cells 
Experimental Cell Research  2013;319(4):536-545.
Epidemiological studies report a negative association between circulating bilirubin concentrations and the risk for cancer and cardiovascular disease. Structurally related tetrapyrroles also possess in vitro anti-genotoxic activity and may prevent mutation prior to malignancy. Furthermore, few data suggest that tetrapyrroles exert anti-carcinogenic effects via induction of cell cycle arrest and apoptosis. To further investigate whether tetrapyrroles provoke DNA-damage in human cancer cells, they were tested in the single cell gel electrophoresis assay (SCGE). Eight tetrapyrroles (unconjugated bilirubin, bilirubin ditaurate, biliverdin, biliverdin-/bilirubin dimethyl ester, urobilin, stercobilin and protoporphyrin) were added to cultured Caco2 and HepG2 cells and their effects on comet formation (% tail DNA) were assessed. Flow cytometric assessment (apoptosis/necrosis, cell cycle, intracellular radical species generation) assisted in revealing underlying mechanisms of intracellular action. Cells were incubated with tetrapyrroles at concentrations of 0.5, 5 and 17 μM for 24 h. Addition of 300 μM tertiary-butyl hydroperoxide to cells served as a positive control. Tetrapyrrole incubation mostly resulted in increased DNA-damage (comet formation) in Caco2 and HepG2 cells. Tetrapyrroles that are concentrated within the intestine, including protoporphyrin, urobilin and stercobilin, led to significant comet formation in both cell lines, implicating the compounds in inducing DNA-damage and apoptosis in cancer cells found within organs of the digestive system.
► DNA-damaging effects of bile pigments have been rarely investigated. ► Thus, eight tetrapyrroles were tested for DNA-damaging effects in the comet assay. ► To assess DNA damage, cancer cells were used, and flow cytometry parameters were measured. ► Especially protoporphyrin, urobilin and stercobilin increased DNA strand breaks significantly. ► Mechanisms could include oxidative stress, cell cycle arrest and apoptosis.
PMCID: PMC3569715  PMID: 23246570
BP(s), bile pigment(s); BR, unconjugated bilirubin; BR-DME, Bilirubin dimethyl ester; BRf, free bilirubin; BRDT, bilirubin ditaurate; BV, biliverdin; BV-DME, biliverdin dimethyl ester; PRO, protoporphyrin; SCGE, single cell gel electrophoresis; TP(s), tetrapyrrole(s); SB, stercobilin; UB, urobilin; Stercobilin; Urobilin; Protoporphyrin; SCGE; Comet
17.  Reduced circulating oxidized LDL is associated with hypocholesterolemia and enhanced thiol status in Gilbert syndrome 
Free Radical Biology & Medicine  2012;52(10):2120-2127.
A protective association between bilirubin and atherosclerosis/ischemic heart disease clearly exists in vivo. However, the relationship between bilirubin and in vivo oxidative stress parameters in a clinical population remains poorly described. The aim of this study was to assess whether persons expressing Gilbert syndrome (GS; i.e., unconjugated hyperbilirubinemia) are protected from thiol oxidation and to determine if this, in addition to their improved lipoprotein profile, could explain reduced oxidized low-density lipoprotein (oxLDL) status in them. Forty-four matched GS and control subjects were recruited and blood was prepared for the analysis of lipid profile and multiple plasma antioxidants and measures of oxidative stress. GS subjects possessed elevated plasma reduced thiol (8.03±1.09 versus 6.75±1.39 nmol/mg protein; P<0.01) and glutathione concentrations (12.7±2.39 versus 9.44±2.45 μM; P<0.001). Oxidative stress status (reduced:oxidized glutathione; GSH:GSSG) was significantly improved in GS (0.49±0.16 versus 0.32±0.12; P<0.001). Protein carbonyl concentrations were negatively associated with bilirubin concentrations and were significantly lower in persons with >40 μM bilirubin versus controls (<17.1 μmol/L; P<0.05). Furthermore, absolute oxLDL concentrations were significantly lower in GS subjects (P<0.05). Forward stepwise regression analysis revealed that bilirubin was associated with increased GSH:GSSG ratio and reduced thiol concentrations, which, in addition to reduced circulating LDL, probably decreased oxLDL concentrations within the cohort. In addition, a marked reduction in total cholesterol concentrations in hyperbilirubinemic Gunn rats is presented (Gunn 0.57±0.09 versus control 1.69±0.40 mmol/L; P<0.001), arguing for a novel role for bilirubin in modulating lipid status in vivo. These findings implicate the physiological importance of bilirubin in protecting from atherosclerosis by reducing thiol and subsequent lipoprotein oxidation, in addition to reducing circulating LDL concentrations.
► Bilirubin is associated with the prevention of thiol and protein oxidation in vivo. ► Gilbert syndrome subjects have higher plasma antioxidants and improved oxidative stress status versus controls. ► Elevated bilirubin is associated with improved lipid status in rodents and humans. ► Bilirubin may act via multiple pathways to prevent cardiovascular disease.
PMCID: PMC3377994  PMID: 22521902
BMI, body mass index; CVD, cardiovascular disease; DTNB, 5,5-dithiobis(2-nitrobenzoic acid); FRAP, ferric reducing ability of plasma; GS, Gilbert syndrome; GSH, reduced glutathione; GSSG, oxidized glutathione; HDL, high-density lipoprotein; HO-1, heme oxygenase-1; HPLC, high-performance liquid chromatography; LDL, low-density lipoprotein; oxLDL, oxidized low-density lipoprotein; TCA, trichloroacetic acid; TEAC, Trolox equivalent antioxidant capacity; UGT, uridine diphosphate glucuronosyltransferase; Cardiovascular disease; Bile pigment; Thiol; Glutathione; Bilirubin; Free radicals
18.  Fractionation of an Extract of Pluchea odorata Separates a Property Indicative for the Induction of Cell Plasticity from One That Inhibits a Neoplastic Phenotype 
Introduction. Several studies demonstrated that anti-inflammatory remedies exhibit excellent anti-neoplastic properties. An extract of Pluchea odorata (Asteraceae), which is used for wound healing and against inflammatory conditions, was fractionated and properties correlating to anti-neoplastic and wound healing effects were separated. Methods. Up to six fractionation steps using silica gel, Sephadex columns, and distinct solvent systems were used, and eluted fractions were analysed by thin layer chromatography, apoptosis, and proliferation assays. The expression of oncogenes and proteins regulating cell migration was investigated by immunoblotting after treating HL60 cells with the most active fractions. Results. Sequential fractionations enriched anti-neoplastic activities which suppressed oncogene expression of JunB, c-Jun, c-Myc, and Stat3. Furthermore, a fraction (F4.6.3) inducing or keeping up expression of the mobility markers MYPT, ROCK1, and paxillin could be separated from another fraction (F4.3.7), which inhibited these markers. Conclusions. Wound healing builds up scar or specific tissue, and hence, compounds enhancing cell migration support this process. In contrast, successful anti-neoplastic therapy combats tumour progression, and thus, suppression of cell migration is mandatory.
PMCID: PMC3312255  PMID: 22474515
19.  Inhalative Exposure to Vanadium Pentoxide Causes DNA Damage in Workers: Results of a Multiple End Point Study 
Environmental Health Perspectives  2008;116(12):1689-1693.
Inhalative exposure to vanadium pentoxide (V2O5) causes lung cancer in rodents.
The aim of the study was to investigate the impact of V2O5 on DNA stability in workers from a V2O5 factory.
We determined DNA strand breaks in leukocytes of 52 workers and controls using the alkaline comet assay. We also investigated different parameters of chromosomal instability in lymphocytes of 23 workers and 24 controls using the cytokinesis-block micronucleus (MN) cytome method.
Seven of eight biomarkers were increased in blood cells of the workers, and vanadium plasma concentrations in plasma were 7-fold higher than in the controls (0.31 μg/L). We observed no difference in DNA migration under standard conditions, but we found increased tail lengths due to formation of oxidized purines (7%) and pyrimidines (30%) with lesion-specific enzymes (formamidopyrimidine glycosylase and endonuclease III) in the workers. Bleomycin-induced DNA migration was higher in the exposed group (25%), whereas the repair of bleomycin-induced lesions was reduced. Workers had a 2.5-fold higher MN frequency, and nucleoplasmic bridges (NPBs) and nuclear buds (Nbuds) were increased 7-fold and 3-fold, respectively. Also, apoptosis and necrosis rates were higher, but only the latter parameter reached statistical significance.
V2O5 causes oxidation of DNA bases, affects DNA repair, and induces formation of MNs, NPBs, and Nbuds in blood cells, suggesting that the workers are at increased risk for cancer and other diseases that are related to DNA instability.
PMCID: PMC2599764  PMID: 19079721
comet assay; cytokinesis-block micronucleus assay; DNA damage; occupational exposure; vanadium pentoxide

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