Toxicology Letters (TOXICOL LETT)

Publications in this journal

• Article: Metallothionein prevention of arsenic trioxide-induced cardiac cell death is associated with its inhibition of mitogen-activated protein kinases activation in vitro and in vivo.

  Xiao Miao, Guanfang Su, Yonggang Wang, Weixia Sun, Wei Wei, Wei Li, Lining Miao, Lu Cai, Yi Tan, Qiuju Liu
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  ABSTRACT: Cardiotoxicity induced by arsenic trioxide has become a serious blockade of clinical applications of this effective anticancer agent. The general mechanism responsible for arsenic cardiotoxicity has been attributed to its induction of oxidative stress. Metallothionein (MT) has been extensively proven to be a potent endogenous antioxidant that protects heart against oxidative stress-induced cardiac damage. To investigate whether and how MT protects against arsenic cardiotoxicity, MT-overexpressing H9c2 (MT-H9c2) cardiac cells and transgenic (MT-TG) mice with their corresponding controls were exposed to the clinical relevant dose of arsenic trioxide. Cardiac cell apoptosis was detected by molecular indices, including the cleavage of caspase 3 and caspase 12, Bax/Bcl2 expression ratio, CHOP expression and/or confirmed by a terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling assay. Arsenic trioxide dose- and time-dependently induced cardiac cell death in H9c2 cells with a significant activation of major MAPK subfamily members such as ERK1/2, JNK and p38, but not in MT-H9c2 cells. Importantly, the protective effect of MT on arsenic trioxide-induced apoptotic cell death was completely recaptured in the heart of MT-TG with a significant prevention of MAPKs activation. These results indicate that arsenic trioxide-upregulated MAPKs might play important role in arsenic trioxide-induced apoptotic cell death in cardiac cells both in vivo and in vitro, and MT's suppression of arsenic trioxide apoptotic effect was associated with the inhibition of MAPK activation. Therefore, selective elevation of cardiac MT levels with pharmacological approaches may be a potential strategy for the prevention of arsenic cardiotoxicity.
  Toxicology Letters 05/2013;
• Article: Diosmin abrogates chemically induced hepatocarcinogenesis via alleviation of oxidative stress, hyperproliferative and inflammatory markers in murine model.

  Mir Tahir, Muneeb U Rehman, Abdul Lateef, Abdul Quaiyoom Khan, Rehan Khan, Wajhul Qamar, Oday O'Hamiza, Farrah Ali, Syed Kazim Hasan, Sarwat Sultana
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  ABSTRACT: Hepatocellular carcinoma (HCC) is a global health problem and is fourth leading cause of cancer related deaths. Now-a-days new strategies have been accounted for the chemoprevention of liver cancer due to ineffective traditional treatments against HCC. In the present study, we have shown that diosmin attenuates 2-AAF induced hepatic toxicity and early tumour promotion markers (ODC, PCNA and Ki67), its chemopreventive efficacy against DEN initiated and 2-AAF promoted hyper-proliferation and hepatocarcinogenesis in Wistar rats. Hepatocarcinogenesis has been characterised by the presence of apparent hepatic nodules, hepatic proliferation, elevation in the levels of proliferation markers (PCNA and Ki67), and inflammatory markers (COX-2 and iNOS) in DEN and 2-AAF administered rats. Protective efficacy of diosmin has been investigated in terms of its potential in reducing the percentage of visible hepatic nodules and the restoration of early tumor markers (PCNA, Ki67 and ODC), oxidative stress biomarkers, serum cytotoxicity markers (AST, ALT and LDH), cell necrosis markers (NF- kappa B and TNF-α) and inflammatory markers (COX-2 and iNos). Our study demonstrates that the inhibition of cell proliferation and down regulation of inflammatory markers may be, at least in part, the underlying mechanisms related to the liver tumor inhibition by diosmin. The present study allows us to conclude that diosmin being a dietary supplement, could be used as chemopreventive agent to prevent hepatocarcinogenesis.
  Toxicology Letters 05/2013;
• Article: Protein Binding Modulates the Cellular Uptake of Silver Nanoparticles Into Human Cells: Implications for In Vitro to In Vivo Extrapolations?

  Nancy A Monteiro-Riviere, Meghan E Samberg, Steven J Oldenburg, Jim E Riviere
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  ABSTRACT: Nanoparticles (NP) absorbed in the body will come in contact with blood proteins and form NP/protein complexes termed protein coronas, which may modulate NP cellular uptake. This study quantitated human epidermal keratinocyte (HEK) uptake of silver (Ag) NP complexed to different human serum proteins. Prior to HEK dosing, AgNP (20nm and 110nm citrate BioPure™; 40nm and 120nm silica-coated) were preincubated for 2h at 37°C without (control) or with physiological levels of albumin (44mg/ml), IgG (14.5mg/ml) or transferrin (3mg/ml) to form protein-complexed NP. HEK were exposed to the protein incubated AgNP for 3h, rinsed and incubated for 24h, rinsed in buffer and lysed. Ag was assayed by inductively-coupled plasma optical emission spectrometry. Uptake of Ag in HEK was<4.1% of applied dose with proteins suppressing citrate, but not silica coated Ag uptake. IgG exposure dramatically reduced 110nm citrate AgNP uptake. In contrast, greatest uptake of 20nm silica AgNP was seen with IgG, while 110nm silica AgNP showed minimal protein effects. Electron microscopy confirmed cellular uptake of all NP but showed differences in the appearance and agglomeration state of the NP within HEK vacuoles. This work suggests that NP association with different serum proteins, purportedly forming different protein coronas, significantly modulates Ag uptake into HEK compared to native NP uptake, suggesting caution in extrapolating in vitro uptake data to predict behavior in vivo where the nature of the protein corona may determine patterns of cellular uptake, and thus biodistribution, biological activity and toxicity.
  Toxicology Letters 05/2013;
• Article: Attenuation of Subchronic Formaldehyde Inhalation Toxicity With Oral Administration of Glutamate, Glycine and Methionine.

  Boris A Katsnelson, Tamara D Degtyareva, Larisa I Privalova, Ilzira A Minigaliyeva, Tatiana V Slyshkina, Vladimir V Ryzhov, Olga Yu Beresneva
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  ABSTRACT: Inhalation exposure of outbred female white rats (initial age about 4 months) to formaldehyde vapours (12.8±0.69mg/m(3)) 4hrs per day, 5 days per week during 10 weeks induced statistically significant changes in some indices characterizing differential WBC count, functional status of the central nervous system and liver, redox and porphyrin metabolisms, bone marrow micronuclei count as well as free amino acid spectrum of the blood serum. The development of intoxication was accompanied by increased urinary excretion of formaldehyde, formic acid and methanol. Daily oral administration of glutamate (150-180mg), glycine (12mg) and methionine (50mg) in combination rendered all of the formaldehyde's toxic effects reduced. This administration also caused a significant increase in the ratio between the rates of excretion of formic acid and non-metabolized formaldehyde. This shift supposedly reflects activation of oxidative detoxifying biotransformation of formaldehyde. Taking into consideration that the combination of amino acids used in this study proved innocuous in protectively effective doses, the administration in this combination may be recommended to humans exposed to high levels of formaldehyde in workplace or ambient air.
  Toxicology Letters 05/2013;
• Article: Sanguinarine induces apoptosis in human colorectal cancer HCT-116 cells through ROS-mediated Egr-1 activation and mitochondrial dysfunction.

  Min Ho Han, Gi-Young Kim, Young Hyun Yoo, Yung Hyun Choi
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  ABSTRACT: We examined the effects of sanguinarine, a benzophenanthridine alkaloid, on reactive oxygen species (ROS) production and the association of these effects with apoptotic cell death in a human colorectal cancer HCT-116 cell line. Sanguinarine generated ROS, which was followed by a decrease in the mitochondrial membrane potential (MMP), the activation of caspase-9 and -3, and the down-regulation of anti-apoptotic proteins, such as Bcl2, XIAP and cIAP-1. Sanguinarine also promoted the activation of caspase-8 and truncation of Bid (tBid). However, the quenching of ROS generation by N-acetyl-L-cysteine, a scavenger of ROS, reversed the sanguinarine-induced apoptosis effects via inhibition of the MMP collapse, tBid expression, and activation of caspases. Sanguinarine also markedly induced the expression of the early growth response gene-1 (Egr-1) during the early period, after which expression level was decreased. In addition, HCT-116 cells transfected with Egr-1 siRNA displayed significant blockage of sanguinarine-induced apoptotic activity in a ROS-dependent manner. These observations clearly indicate that ROS, which are key mediators of Egr-1 activation and MMP collapse, are involved in the early molecular events in the sanguinarine-induced apoptotic pathway acting in HCT-116 cells.
  Toxicology Letters 05/2013;
• Article: Dual inhibitor of phosphoinositide 3-kinase/mammalian target of rapamycin NVP-BEZ235 effectively inhibits cisplatin-resistant urothelial cancer cell growth through autophagic flux.

  Jian-Ri Li, Chen-Li Cheng, Chi-Rei Yang, Yen-Chuan Ou, Ming-Ju Wu, Jiunn-Liang Ko
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  ABSTRACT: Purpose: Therapeutically induced autophagic cell death has been proven to be effective in cases of solid tumors. The dual phosphatidylinositol 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) inhibitor NVP-BEZ235 possesses antitumor activity against solid tumors. Inhibition of mTOR has been shown to elicit autophagy. In this study, we examined the antiproliferation and autophagic activities of NVP-BEZ235 in parental and cisplatin-resistant urothelial carcinoma (UC) cells. Materials and Methods: Two UC cell lines, NTUB1 and a cisplatin-resistant subline N/P(14), were applied to examine the cytotoxic effect of NVP-BEZ-235. The cell death mechanism was also evaluated. Results: NVP-BEZ235 was effective in inhibiting the growth of UC cells including parental and cisplatin-resistant cells on flow cytometry assay and Western blot. Although NVP-BEZ235 did not induce LC3-II conversion, it did elicit acidic vesicular organelle (AVO) development on flow cytometry. On Western blot, NVP-BEZ235 decreased p62 and phospho-Rb expressions in a concentration-dependent manner. GFP-LC3 conversion and the appearance of cleaved-GFP following NVP-BEZ235 treatment were demonstrated on Western blot. In addition, lysosomotropic inhibition of autophagy by chloroquine (CQ), an agent that is currently in clinical use and a known antagonist of autophagy, resulted in proliferation of UC cells. Thus, inhibition of autophagic flux by CQ appears to be a survival mechanism that counteracts the anticancer effects of NVP-BEZ235. Conclusions: We demonstrated that NVP-BEZ235 inhibits UC cell proliferation by activating autophagic flux and cell cycle arrest, but does not induce apoptotic cell death. Our findings suggest that the anticancer efficacy of NVP-BEZ235 is due to autophagic flux and co-treatment with CQ counteracts the cytotoxic effect.
  Toxicology Letters 05/2013;
• Article: Nephroprotective effect of GSK-3β inhibition by lithium ions and δ-opioid receptor agonist dalargin on gentamicin-induced nephrotoxicity.

  E Y Plotnikov, O A Grebenchikov, V A Babenko, I B Pevzner, L D Zorova, V V Likhvantsev, D B Zorov
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  ABSTRACT: Nephrotoxicity and ototoxicity are the most considerable side effects of aminoglycoside antibiotics, such as gentamicin that seriously limits its application in medicine. The major mechanism of negative effect of gentamicin on kidney cells involves damage of mitochondria and induction of an oxidative stress that causes cell death resulting in kidney dysfunction. In this work we compared effects of the lithium ions and δ-opioid receptors agonist, dalagrin on gentamicin-induced kidney injury. It was revealed that LiCl and dalargin treatment reduced renal tubular cell death and diminished kidney injury caused by gentamicin. Both LiCl and dalargin were found to enhance phosphorylation of glycogen synthase kinase 3β in the kidney which points to induction of nephroprotective signaling pathways. Thus, we conclude that lithium ions and dalargin might be considered as novel promising agents for future use to prevent negative consequences of therapy with aminoglycoside antibiotics.
  Toxicology Letters 05/2013;
• Article: Interactive effects of smoking and glutathione S-transferase polymorphisms on the development of non-alcoholic fatty liver disease.

  Kentaro Oniki, Masaharu Hori, Junji Saruwatari, Kazunori Morita, Ayami Kajiwawa, Misaki Sakata, Shuichi Mihara, Yasuhiro Ogata, Kazuko Nakagawa
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  ABSTRACT: Glutathione S-transferases (GSTs) protect cells against exogenous and endogenous oxidative stress. GST polymorphisms are associated with the development of cardiovascular disease (CVD) and diabetes mellitus (DM), especially in current-smokers. Non-alcoholic fatty liver disease (NAFLD) is a predictor of future CVD or DM, because oxidative stress contributes to their pathogenesis. This study investigated whether the combination of smoking status and GST genotypes could affect the risk for NAFLD. A cross-sectional analysis was conducted among 713 Japanese participants (458 males and 255 females) during a health screening program. The GSTM1 null, GSTT1 null, GSTP1 *A/*B or *B/*B and GSTA1 *A/*B or *B/*B genotypes were determined and deemed to be high-risk genotypes. The prevalence of NAFLD was 18.7%. Among never-smokers, carriers of one, and those of two or more high-risk GSTM1, GSTP1 or GSTA1 genotypes were at a higher risk for NAFLD than those who were not carriers [odds ratio (95% confidence interval): 2.6 (1.1-5.9) and 3.3 (1.3-8.1), respectively], and the risk was further increased among current-smokers [4.6 (1.6-13.0) and 5.4 (1.2-23.7), respectively]. This is the first report to show that the combination of current-smoking and harboring high-risk GSTM1, GSTP1 and/or GSTA1 genotypes is interactively associated with the risk of NAFLD.
  Toxicology Letters 04/2013;
• Article: Indoxyl 3-sulfate stimulates Th17 differentiation enhancing phosphorylation of c-Src and STAT3 to worsen experimental autoimmune encephalomyelitis.

  Sung-Jun Hwang, You-Jung Hwang, Mi-Ok Yun, Jong-Hee Kim, Gap-Soo Oh, Joo-Hung Park
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  ABSTRACT: Although AhR activation regulates CD4T cell differentiation, how it works has yet to be elucidated. In the present study, using in vitro Th17 differentiation model, we examined effects of AhR activation by indoxyl 3-sulfate (I3S), a uremic toxin, on Th17 differentiation and investigated underlying mechanisms. I3S increased expression of RORγt, the master transcription factor for Th17 differentiation, and stimulated Th17 differentiation, in a comparative manner as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a prototypical AhR ligand. Activation of STAT3, which is phosphorylated by the IL-6 signaling pathways and thus is necessary for Th17 differentiation, was strongly stimulated by I3S and TCDD. Phosphorylation of c-Src, which was shown to be activated by AhR ligands, was also increased by I3S and TCDD, and blocking of c-Src activity by 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo[3,4-d]pyrimidine (PP2) inhibited phosphorylation of both c-Src and STAT3, raising a possibility that stimulatory activities of I3S and TCDD on Th17 differentiation could be exerted via increased phosphorylation of c-Src, which in turn stimulates STAT3 activation. Finally, we found that I3S worsened experimental autoimmune encephalomyelitis (EAE), which is primarily mediated by Th17 cells, enhancing the frequency of IL-17-producing cells in draining lymph nodes.
  Toxicology Letters 04/2013;
• Article: Bone Morphogenetic Protein-7 inhibits silica-induced pulmonary fibrosis in rats.

  Gengxia Yang, Zhonghui Zhu, Yan Wang, Ai Gao, Piye Niu, Lin Tian
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  ABSTRACT: Bone morphogenetic protein-7 (BMP-7) has been shown to inhibit liver and renal fibrosis in in vivo and in vitro studies. There is no study to investigate BMP-7's role in the development of pulmonary fibrosis induced by silica. In the current study, we used the rat model to explore the potential antifibrotic role of BMP-7 and its underlying mechanism in silica-induced pulmonary fibrosis. Sixty Wistar rats were randomly assigned into three groups. Control group received saline, silica group received silica and BMP-7 treated group received silica and BMP-7. BMP-7 was administered to silica-treated rats intraperitoneally at a dose of 300μg/kg/injection from day 8 to day 30 every other day. After the animals were sacrificed on day 15 and 30, hydroxyproline levels, the protein expressions of BMP/Smad and TGF-β/Smad signaling, and histopathology in lung tissues were analyzed. The hydroxyproline contents in BMP-7 treated groups were significantly lower than the silica groups (P<0.05). Histopathological results showed BMP-7 could reduce the progression of silica induced fibrosis. Furthermore, the expression of p-Smad1/5/8, a marker of BMP/Smad signaling, was significantly up-regulated in BMP-7 treated groups (P<0.05) compared with the silica groups. On the contrary, the expression of p-Smad2/3, a marker for TGF-β/Smad signaling, reduced significantly in BMP-7-treated groups compared with silica groups (P<0.05). In conclusion, the pulmonary fibrosis induced by silica in rats was significantly reduced with the therapeutic treatment of BMP-7. The antifibrotic effect of BMP-7 could be related to the activation of BMP/Smad signaling and inhibition of TGF-β/Smad pathways.
  Toxicology Letters 04/2013;
• Article: Differential Induction of Cytochrome P450 Isoforms and Peroxisomal Proliferation by Cyfluthrin in Male Wistar Rats.

  A Anadón, M A Martínez, M Martínez, V Castellano, I Ares, A Romero, R Fernández, M R Martínez-Larrañaga
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  ABSTRACT: Cyfluthrin effects on in vivo drug metabolizing enzymes were evaluated using the oxidative substrate antipyrine. Antipyrine pharmacokinetics in plasma and urinary excretion of its major metabolites with and without cyfluthrin oral treatment (20mg/kg/day for 6 days) were investigated in rats. Cyfluthrin increased the apparent intrinsic clearance and decreased the antipyrine half-life at β phase. Cyfluthrin also increased the clearance of the antipyrine metabolites, norantipyrine, 4-hydroxyantipyrine and 3-hydroxymethylantipyrine and the formation rate constants for each of the three metabolites measured in urine. These results suggest that cyfluthrin affects hepatic cytochrome P450 (CYP) system. In order to confirm, a second experiment was carried out. We evaluated the effects of repeated exposure to cyfluthrin on hepatic and renal CYP2E, CYP1A and CYP4A subfamilies and peroxisomal proliferation in rats following oral administration (10 and 20mg/kg/day for 6 days). At the highest dose, cyfluthrin increased renal and hepatic O-deethylation of ethoxyresorufin and O-demethylation of methoxyresorufin, metabolism mediated by the CYP1A subfamily. Liver and kidney were susceptible to cyfluthrin-dependent induction of 12- and 11-hydroxylation of lauric acid, suggesting CYP4A subfamily induction. Also cyfluthrin increased the β-oxidation of palmitoyl-coenzyme A and carnitine acetyltransferase activity, supporting cyfluthrin as a peroxisome proliferator. In conclusion, the demonstration that cyfluthrin induced hepatic CYP1A, CYP4A subfamilies and peroxisomal proliferation raises the possibility of cyfluthrin could produce changes in oxidative stress.
  Toxicology Letters 04/2013;
• Article: PF-04691502 triggers cell cycle arrest, apoptosis and inhibits the angiogenesis in hepatocellular carcinoma cells.

  Feng-Ze Wang, Peng-Jiao, Na-Na Yang, Chuang-Yuan, Ya-Li Zhao, Qiang-Qiang Liu, Hong-Rong Fei, Ji-Guo Zhang
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  ABSTRACT: Hepatocellular carcinoma (HCC) is a major cause of morbidity and mortality in the world. The aim of the present study is to determine the antitumor effect of PF-04691502, a potent inhibitor of PI3K and mTOR kinases, on the apoptosis and angiogenesis of the hepatoma cancer cells. Our results indicate that treatment of cancer cells with PF-04691502 reduces cell viability and inhibits cell growth in a dose-dependent manner. PF-04691502 triggers apoptosis via a mitochondrial pathway, accompanied by activation of caspase-3, caspase-9, and Poly(ADP-Ribose) Polymerase (PARP). Pre-treatment of hepatoma cells with the caspase-3 inhibitor (z-DEVD-fmk) blocks the PF-04691502-induced death of these cells. In addition, growth factors-induced tube formation and the migration of HUVECs are markedly inhibited by PF-04691502 treatment. The mechanisms of anti-angiogenesis of PF-04691502 are associated with inhibiting the expression of VEGF and HIF-1α. Based on the overall results, we suggest that PF-04691502 reduces hepatocellular carcinoma cell viability, induces cell apoptosis, and inhibits cell growth and tumor angiogenesis, implicating its potential therapeutic value in the treatment of HCC.
  Toxicology Letters 04/2013;
• Article: Acute effects of an exposure to 100ppm 1-methoxypropanol-2 on the upper airways of human subjects.

  A Muttray, J Gosepath, J Brieger, A Faldum, O Mayer-Popken, D Jung, B Roßbach, W Mann, S Letzel
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  ABSTRACT: The German MAK value of 1-methoxypropanol-2 has been fixed at 100ppm. The aim of this study was to evaluate possible acute effects of an exposure to 100ppm 1-methoxypropanol-2 on the upper airways of human subjects. Twenty subjects were exposed in a crossover design to 100ppm 1-methoxypropanol-2 and to air in an exposure chamber for 4hours. Subjective symptoms were assessed by questionnaire. Olfactory thresholds for n-butanol and mucociliary transport time were measured before and after exposure. Concentrations of interleukin 1ß and interleukin 8 were determined in nasal secretions taken after exposure. mRNA levels of interleukins 1ß, 6 and 8, tumor necrosis factor α, granulocyte-macrophage colony-stimulating factor, monocyte chemotactic protein 1, and cyclooxygenases 1 and 2 were measured in nasal epithelial cells, obtained after exposure. Possible effects were investigated by semiparametric and parametric cross-over analyses. Subjects did not have any subjective irritating symptoms. The olfactory threshold was slightly elevated following exposure to 1-methoxypropanol-2. Mucociliary transport time did not change. Neither concentrations of interleukins in nasal secretions nor mRNA levels except for interleukin 1ß were higher after exposure to 1-methoxypropanol-2. In conclusion, the acute exposure to 100ppm 1-methoxypropanol-2 did not cause clear-cut adverse effects in test subjects.
  Toxicology Letters 04/2013;
• Article: Hyaluronidase: Its effects on HI-6 dichloride and dimethanesulphonate pharmacokinetic profile in pigs.

  Jana Zdarova Karasova, Michal Pavlík, Jaroslav Chladek, Daniel Jun, Kamil Kuca
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  ABSTRACT: Pigs were administered intramuscularly molar equivalents of HI-6 salts (HI-6 dichloride-10.71mg/kg and HI-6 DMS 13.59mg/kg) either with or without hyaluronidase (60 U/kg). Hyaluronidase is supposed to increase tissue permeability and diminishes discomfort caused by the intramuscular injection. Doses of HI-6 salts corresponded with standard HI-6 dichloride dose in one autoinjector (500mg) and were recalculated for one kilogram of body weight. According to the results, both HI-6 salts applied in combination with hyaluronidase had increased tissue absorption and improved pharmacokinetic profile. The Cmax was significantly higher in case of HI-6 DMS plus hyaluronidase (29.6±2.98μg/ml) administration increase compared to HI-6 DMS (23.8±3.04μg/ml) and HI-6 dichloride (19.0±0.93μg/ml); both without hyaluronidase. Bioavailability calculated as AUCtotal (HI-6 DMS with hyaluronidase, 4119±647min.μg/ml) was also significantly higher compared to HI-6 DMS (2259±329min.μg/ml) and HI-6 dichloride (1969±254min.μg/ml); both without hyaluronidase. The results suggest that administration of HI-6 salt with higher solubility is the first step in the improvement of application strategy, but use some substances with spreading effect (hyaluronidase) may also leads to better absorption and better bioavailability. Improved bioavailability could to go hand in hand with increased effectiveness of therapy without the need of multiple autoinjector applications.
  Toxicology Letters 04/2013;
• Article: New Insights into the Human Metabolism of the Fusarium Mycotoxins Deoxynivalenol and Zearalenone.

  Benedikt Warth, Michael Sulyok, Franz Berthiller, Rainer Schuhmacher, Rudolf Krska
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  ABSTRACT: This study reports on the detailed investigation of human deoxynivalenol (DON) and zearalenone (ZEN) in vivo metabolism through the analysis of urine samples obtained from one volunteer following a naturally contaminated diet containing 138μg DON and 10μg ZEN over a period of four days. Based on the mycotoxin intake and the concentrations of mycotoxin conjugates in urine, a mass balance was established. The average rates of DON excretion and glucuronidation were determined to be 68 and 76%, respectively. The investigation of formed glucuronides revealed DON-15-glucuronide as main conjugation product besides DON-3-glucuronide. Furthermore, for the first time in human urine a third DON-glucuronide was detected and the fate of ingested masked DON forms (3-acetyl-DON and DON-3-glucoside) was preliminary assessed. The mean excretion rate of ZEN was determined to be 9.4%. ZEN was mainly present in its glucuronide form and in some samples ZEN-14-glucuronide was directly determined 3-10h after exposure. For the first time concrete figures have become available for the excretion pattern of DON and ZEN-glucuronides throughout a day, the comparison of total DON in 24h and first morning urine samples and the urinary excretion rate of total ZEN in humans following exposure through naturally contaminated food. Therefore, valuable preliminary information has been obtained through the chosen experimental approach although the study involved only one single individual and needs to be confirmed in larger monitoring studies. The presented experiment contributes to a better understanding of human DON and ZEN in vivo metabolism and thereby supports advanced exposure and risk assessment to increase food safety and examine the relationship between these mycotoxins and potentially associated chronic diseases in the future.
  Toxicology Letters 04/2013;
• Article: Interlaboratory evaluation of a cow's milk allergy mouse model to assess the allergenicity of hydrolysed cow's milk based infant formulas.

  B C A M van Esch, J H M van Bilsen, P V Jeurink, J Garssen, A H Penninks, J J Smit, R H H Pieters, L M J Knippels
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  ABSTRACT: This study describes two phases of a multi-phase project aiming to validate a mouse model for cow's milk allergy to assess the potential allergenicity of hydrolysed cow's milk based infant formulas (claim support EC-directive 2006/141/E). The transferability and the discriminatory power of this model was evaluated in 4 research centers. Mice were sensitized by oral gavage with whey or extensively hydrolysed whey (eWH) using cholera toxin as an adjuvant. Whey-specific antibodies, mMCP-1 levels, anaphylactic shock symptoms, body temperature and the acute allergic skin response were determined upon whey challenge. In phase I and II, all 4 centers detected elevated levels of whey-specific IgE/IgG1 in whey sensitized animals. Elevated levels of mMCP-1, anaphylactic symptoms, body temperature drop and acute allergic skin response were scored upon whey challenge in 3 out of 4 research centers. In contrast, none of the evaluated parameters were elevated in eWH orally exposed groups. The cow's milk allergy mouse model is capable to distinguish the sensitizing capacity of complete or hydrolysed cow's milk protein. The model uses straightforward parameters relevant to food allergic responses and can be effectively transferred between different laboratories. We propose this mouse model as a new strategy for the screening of new hypoallergenic cow's milk formulas.
  Toxicology Letters 04/2013;
• Article: Expression of WWOX and FHIT is downregulated by exposure to arsenite in human uroepithelial cells.

  Ya-Chun Huang, Wen-Chun Hung, Wan-Tzu Chen, Hsin-Su Yu, Chee-Yin Chai
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  ABSTRACT: Ecological studies in Taiwan, Chile, Argentina, Bangladesh, and Mexico have confirmed significant dose-dependent associations between ingestion of arsenic-contaminated drinking water and the risk of various human malignancies. The FHIT and WWOX genes are active in common fragile sites FRA3B and FRA16D, respectively. Reduced expression of FHIT or WWOX is known to be an early indicator of carcinogen-induced cancers. However, the effect of arsenite on the expressions and molecular mechanisms of these markers is still unclear. The aims of this study were (i) to observe the expression of ATR, WWOX and FHIT proteins in urothelial carcinoma (UC) between endemic and non-endemic areas of blackfoot disease (BFD) by immunohistochemical analyses; (ii) to compare expression of these genes between arsenite-treated SV-HUC-1 human epithelial cells and rat uroepithelial cells and (iii) to determine the role of DNMT and MEK inhibitors on expressions of WWOX and FHIT in response to arsenite in SV-HUC-1. The experiments revealed that expressions of ATR, WWOX and FHIT in UC significantly differed between BFD areas and non-BFD areas (p=0.003, 0.009 and 0.021, respectively). In fact, the results for the arsenite-treated groups showed that ATR, WWOX and FHIT are downregulated by arsenite in SV-HUC-1. However, the inhibitors suppressed the effects of arsenite on WWOX and FHIT proteins and mRNA expression. In conclusion, arsenite decreased expressions of ATR, WWOX and FHIT via ERK1/2 activation in SV-HUC-1 cells. These findings confirm that dysregulations of these markers may contribute to arsenite-induced carcinogenesis.
  Toxicology Letters 04/2013;
• Article: Smad3 Mediates Cigarette Smoke Extract (CSE) Induction of VEGF Release by Human Fetal Lung Fibroblasts.

  Maha Farid, Nobuhiro Kanaji, Masanori Nakanishi, Yoko Gunji, Joel Michalski, Shunichiro Iwasawa, Jun Ikari, Xingqi Wang, Hesham Basma, Amy J Nelson, Xiangde Liu, Stephen I Rennard
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  ABSTRACT: Cigarette smoke is the major cause of chronic obstructive pulmonary disease (COPD), yet pathogenic mechanisms are not fully understood. Vascular endothelial growth factor (VEGF) is one of the major regulators of endothelial cell survival and is believed to play a role in the pathogenesis of COPD. Fibroblasts are a significant source of VEGF in the lungs; however the effect of cigarette smoke exposure on VEGF release by fibroblasts is not fully understood. We hypothesized that cigarette smoke-induced disturbed VEGF release by human lung fibroblasts is a potential pathogenic mechanism that could contribute to COPD. Cigarette smoke extract (CSE) was prepared by modification of the methods of Carp and Janoff (Am.Rev.Respir.Dis,1978). Human fetal lung fibroblasts (HFL-1) were exposed to different concentrations of CSE and for different durations. VEGF release into the media was measured using ELISA. TGF-β1 receptor (TβR1)/Smad3 as a potential pathway for CSE modulated VEGF release was also investigated using biochemical analyses and siRNA inhibition of Smad3 and siRNA and pharmacologic inhibition of TβR1. CSE induced VEGF release by HFL-1 in concentration and time dependent manner. This was confirmed in two additional types of primary human fetal lung fibroblasts. CSE induced Smad3 phosphorylation and nuclear translocation in HFL-1 cells. Silencing of Smad3 by siRNA not only eliminated the stimulatory effect of CSE on VEGF release but also inhibited baseline VEGF production. Suppression of TβR1 by the pharmacological inhibitor (SB431542) markedly reduced VEGF release by HFL-1 in response to CSE and this effect was confirmed by TβR1 siRNA. In contrast, nicotine inhibited VEGF release by HFL-1 in a dose and time dependent manner. Our findings indicate that CSE stimulates Smad3-mediated VEGF release by lung fibroblasts. Nicotine does not account for the CSE stimulation of VEGF in HFL-1. The ability of lung fibroblasts to produce VEGF may play a role in pathogenesis of cigarette smoke induced lung disease.
  Toxicology Letters 04/2013;
• Article: TEA AND HUMAN HEALTH: THE DARK SHADOWS.

  Jain Aditi, Manghani Chanchal, Kohli Shrey, Nigam Darshika, Rani Vibha
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  ABSTRACT: Tea is one of the most popularly consumed beverage. Depending on the manufacturing process, different varieties of tea can be produced. The antioxidative and antimutagenic potential of tea in cardiovascular diseases, cancer and obesity have long been studied. These therapeutic and nutritional benefits of tea can be attributed to the presence of flavanoids. However, these flavanoids also have certain detrimental effects on human health when their consumption exceeds certain limits. The toxicity of these flavanoids can be attributed to the formation of reactive oxygen species in the body which causes damage to the DNA, lipid membranes etc. The aim of this review is to summarize briefly, the less studied evidences of various forms of toxicity associated with tea and its harmful effects on human health.
  Toxicology Letters 04/2013;
• Article: Vitamin C forestalls cigarette smoke induced NF-κB activation in alveolar epithelial cells.

  Bannhi Das, Palash C Maity, Alok K Sil
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  ABSTRACT: Cigarette smoking causes cellular oxidative stress resulting in inflammatory diseases of lung wherein transcription factor NF-κB plays an important role. It is possible that vitamin C, an antioxidant, may prevent cigarette smoke (CS)-induced NF-κB activation that involves degradation of I-κBɛ and nuclear translocation of c-Rel/p50 in alveolar epithelial cells. Therefore, to examine the hypothesis, we verified the effect of vitamin C on CS-induced expression of NF-κB driven luciferase reporter and NF-κB binding at its target DNA by EMSA in alveolar epithelial A549 cells.We also examined the level of I-κBɛ and sub-cellular distribution of c-Rel by western blotting and immunofluorescence respectively in CSE-treated A549 cells with or without vitamin C pretreatment. We observed a significant reduction in CSEinduced luciferase expression, NF-κB DNA binding, I-κBɛ degradation and c-Rel nuclear translocation in cells pretreated with vitamin C. To further validate the result, we examined sub-cellular distribution of c-Rel in lungs of CS-exposed guinea pigs treated or untreated with vitamin C. Result showed that vitamin C treatment resulted in markedly reduced c-Rel nuclear translocation. All these results demonstrate that vitamin C prevents CS(E)-induced NF-κB activation and thus it could be used for the prevention of CS-induced inflammatory diseases.
  Toxicology Letters 04/2013;