Percorrer por autor "Fernández-Bertólez, Natalia"
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- Adequacy of the standardised in vitro mammalian cell Micronucleus (MN) test for nanomaterials genotoxicity testingPublication . Fernández-Bertólez, Natalia; Rodríguez-Fernández, R.; Lema-Arranz, C.; Pásaro, E.; Brandão, Fátima; Teixeira, João Paulo; Costa, Carla; Valdiglesias, Vanessa; Laffon, BlancaAbout adequacy of the standardised in vitro mammalian cell Micronucleus (MN) test for nanomaterials genotoxicity testing.
- Are iron oxide nanoparticles safe? Current knowledge and future perspectivesPublication . Valdiglesias, Vanessa; Fernández-Bertólez, Natalia; Kiliç, Gözde; Costa, Carla; Costa, Solange; Fraga, Sonia; Bessa, Maria Joao; Pásaro, Eduardo; Teixeira, João Paulo; Laffon, BlancaDue to their unique physicochemical properties, including superparamagnetism, iron oxide nanoparticles (ION) have a number of interesting applications, especially in the biomedical field, that make them one of the most fascinating nanomaterials. They are used as contrast agents for magnetic resonance imaging, in targeted drug delivery, and for induced hyperthermia cancer treatments. Together with these valuable uses, concerns regarding the onset of unexpected adverse health effects following exposure have been also raised. Nevertheless, despite the numerous ION purposes being explored, currently available information on their potential toxicity is still scarce and controversial data have been reported. Although ION have traditionally been considered as biocompatible - mainly on the basis of viability tests results - influence of nanoparticle surface coating, size, or dose, and of other experimental factors such as treatment time or cell type, has been demonstrated to be important for ION in vitro toxicity manifestation. In vivo studies have shown distribution of ION to different tissues and organs, including brain after passing the blood-brain barrier; nevertheless results from acute toxicity, genotoxicity, immunotoxicity, neurotoxicity and reproductive toxicity investigations in different animal models do not provide a clear overview on ION safety yet, and epidemiological studies are almost inexistent. Much work has still to be done to fully understand how these nanomaterials interact with cellular systems and what, if any, potential adverse health consequences can derive from ION exposure.
- Assessment of genotoxic effects of titanium dioxide nanoparticles on different human cell typesPublication . Fernández-Bertólez, Natalia; Brandao, Fátima; Rosário, Fernanda; Bessa, Maria João; Fraga, Sónia; Pásaro, Eduardo; Teixeira, Joao Paulo; Costa, Carla; Laffon, Blanca; Vanessa, ValdiglesiasThe main objective of the present work was to assess the cellular uptake and potential genotoxicity (micronuclei induction) of TiO2 NPs on four diverse human cell lines.
- Assessment of oxidative damage induced by iron oxide nanoparticles on different nervous system cellsPublication . Fernández-Bertólez, Natalia; Costa, Carla; Bessa, Maria João; Park, Magriet; Carriere, Marie; Dussert, Fanny; Teixeira, João Paulo; Pásaro, Eduardo; Laffon, Blanca; Valdiglesias, VanessaIron oxide nanoparticles (ION) have received much attention for their utility in biomedical applications, such as magnetic resonance imaging, drug delivery and hyperthermia, but concerns regarding their potential harmful effects are also growing. Even though ION may induce different toxic effects in a wide variety of cell types and animal systems, there is a notable lack of toxicological data on the human nervous system, particularly important given the increasing number of applications on this specific system. An important mechanism of nanotoxicity is reactive oxygen species (ROS) generation and oxidative stress. On this basis, the main objective of this work was to assess the oxidative potential of silica-coated (S-ION) and oleic acid-coated (O-ION) ION on human SH-SY5Y neuronal and A172 glial cells. To this aim, ability of ION to generate ROS (both in the absence and presence of cells) was determined, and consequences of oxidative potential were assessed (i) on DNA by means of the 8-oxo-7,8-dihydroguanine DNA glycosylase (OGG1)-modified comet assay, and (ii) on antioxidant reserves by analyzing ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG). Conditions tested included a range of concentrations, two exposure times (3 and 24 h), and absence and presence of serum in the cell culture media. Results confirmed that, even though ION were not able to produce ROS in acellular environments, ROS formation was increased in the neuronal and glial cells by ION exposure, and was parallel to induction of oxidative DNA damage and, only in the case of neuronal cells treated with S-ION, to decreases in the GSH/GSSG ratio. Present findings suggest the production of oxidative stress as a potential action mechanism leading to the previously reported cellular effects, and indicate that ION may pose a health risk to human nervous system cells by generating oxidative stress, and thus should be used with caution.
- Avaliação in vitro da neurotoxicidade de nanopartículas de magnetite revestidas por sílicaPublication . Costa, Carla; Brandão, Fátima; Kiliç, Gözde; Fernández-Bertólez, Natalia; Bessa, M. João; Costa, Solange; Valdiglesias, Vanessa; Laffon, Blanca; Teixeira, João Paulo
- Biocompatibility testing and antioxidant properties of cerium dioxide nanoparticles in human nervous system cellsPublication . Fernández-Bertólez, Natalia; Touzani, Assia; Ramos-Pan, Lucía; Reis, Ana Teresa; Teixeira, João Paulo; Laffon, Blanca; Valdiglesias, VanessaCerium dioxide nanoparticles (CeO NP), or nanoceria, are versatile materials with interesting properties for industry and medicine fields, particularly redox properties and catalytic activity. Because of their distinctive features, they have gained high attention in biomedical and pharmacological research to be employed in drug delivery, tissue regeneration, radioprotection, or diagnostic imaging. However, previous works reported that nanoceria may also induce reactive oxygen species (ROS) under certain conditions, leading to cellular stress, cellular damage, or cell death. In this study, the effects of CeO NP on cell viability and morphology as well as their influence on oxidative stress (both oxidant and ROS scavenging capacities) were investigated in nervous system cells (SH-SY5Y neuronal and A172 glial cells) treated with a wide range of CeO NP concentrations (1-100 µg/mL) for several treatment times. Results obtained showed that, despite being stable in time and effectively internalized by both cell types, CeO NP did not produce significant decrease in viability, evaluated by MTT assay, morphological alterations, or intrinsic cell-free ROS, but they generated cellular ROS limited to longer exposure periods. Furthermore, CeO NP demonstrated a certain intrinsic ability to scavenge ROS generated by HO in both tested cell types, more pronounced in neuronal cells. These results confirm the good biocompatibility of nanoceria on human nervous system cells and support further exploring their potential use in biomedicine field, particularly for those therapeutic and diagnostic applications related to the nervous system.
- Cellular and Molecular Toxicity of Iron Oxide NanoparticlesPublication . Laffon, Blanca; Fernández-Bertólez, Natalia; Costa, Carla; Brandão, Fátima; Teixeira, João Paulo; Pásaro, Eduardo; Valdiglesias, VanessaIron oxide nanoparticles (ION) have attracted much attention because of their particular physico-chemical properties, including superparamagnetism. These features make them suitable for many purposes and several interesting biomedical applications, such as to increase contrast in magnetic resonance imaging (MRI), as drug delivery systems and as hyperthermia agents. However, they have also shown to be easily accumulated in diverse tissues and induce toxicity at different levels. This chapter reviews the different cellular and molecular effects induced by ION reported from in vitro studies with human and non-human cell lines. Those effects are mainly dependent on ION type and concentration, time of exposure, presence and nature of coating, and cell type evaluated. They include decreases in viability, plasmatic membrane disruption, oxidative damage, mitochondrial alterations, cell cycle impairments, cytoskeleton disruption, cell death, and alterations in cell motility, and in cell integrity. Despite these negative effects, the numerous advantages of ION together with their promising applications in biomedicine, make it necessary to clearly define their toxicity in order to discard potential health risks and to reach optimal benefits of their use.
- Effect of cytochalasin-B on TIO2 nanoparticles uptake by different cell linesPublication . Brandão, Fátima; Costa, Carla; Fraga, Sónia; Valdiglesias, Vanessa; Fernández-Bertólez, Natalia; Laffon, Blanca; Pásaro, Eduardo; Teixeira, João PauloThe in vitro cytokinesis-block micronucleus cytome assay (CBMN) is widely used for genotoxicity evaluation of nanomaterials (NMs). However, cytochalasin-B (Cyt-B) used in this test may affect the uptake of NMs due to possible interference with endocytosis. Thus, the aim of this study was to investigate the influence of Cyt-B on the uptake of TiO2 nanoparticles (TiO2 NPs) by four different human cell lines: lung cells (A549), glial cells (A172), neurons (SH-SY5Y), and liver cells (HepG2).
- Effects of Zinc Oxide Nanoparticle Exposure on Human Glial Cells and Zebrafish EmbryosPublication . Valdiglesias, Vanessa; Alba-González, Anabel; Fernández-Bertólez, Natalia; Touzani, Assia; Ramos-Pan, Lucía; Reis, Ana Teresa; Moreda-Piñeiro, Jorge; Yáñez, Julián; Laffon, Blanca; Folgueira, MónicaZinc oxide nanoparticles (ZnO NPs) are among the most widely used nanomaterials. They have multiple applications in cosmetics, textiles, paints, electronics and, recently, also in biomedicine. This extensive use of ZnO NPs notably increases the probability that both humans and wildlife are subjected to undesirable effects. Despite being among the most studied NPs from a toxicological point of view, much remains unknown about their ecotoxicological effects or how they may affect specific cell types, such as cells of the central nervous system. The main objective of this work was to investigate the effects of ZnO NPs on human glial cells and zebrafish embryo development and to explore the role of the released Zn2+ ions in these effects. The effects on cell viability on human A172 glial cells were assessed with an MTT assay and morphological analysis. The potential acute and developmental toxicity was assessed employing zebrafish (Danio rerio) embryos. To determine the role of Zn2+ ions in the in vitro and in vivo observed effects, we measured their release from ZnO NPs with flame atomic absorption spectrometry. Then, cells and zebrafish embryos were treated with a water-soluble salt (zinc sulfate) at concentrations that equal the number of Zn2+ ions released by the tested concentrations of ZnO NPs. Exposure to ZnO NPs induced morphological alterations and a significant decrease in cell viability depending on the concentration and duration of treatment, even after removing the overestimation due to NP interference. Although there were no signs of acute toxicity in zebrafish embryos, a decrease in hatching was detected after exposure to the highest ZnO NP concentrations tested. The ability of ZnO NPs to release Zn2+ ions into the medium in a concentration-dependent manner was confirmed. Zn2+ ions did not seem entirely responsible for the effects observed in the glial cells, but they were likely responsible for the decrease in zebrafish hatching rate. The results obtained in this work contribute to the knowledge of the toxicological potential of ZnO NPs.
- Evaluation of cytotoxicity and genotoxicity induced by oleic acid-coated iron oxide nanoparticles in human astrocytesPublication . Fernández-Bertólez, Natalia; Costa, Carla; Brandão, Fátima; Duarte, José Alberto; Teixeira, Joao Paulo; Pásaro, Eduardo; Valdiglesias, Vanessa; Laffon, BlancaIron oxide nanoparticles (ION) are gaining importance as diagnostic and therapeutic tool of central nervous system diseases. Although oleic acid-coated ION (O-ION) have been described as stable and biocompatible, their potential neurotoxicity was scarcely evaluated in human nervous cells so far. The primary aim of this work was to assess the molecular and cellular effects of O-ION on human astrocytes (A172 cells) under different experimental conditions. An extensive set of cyto- and genotoxicity tests was carried out, including lactate dehydrogenase release assay, cell cycle alterations, and cell death production, as well as comet assay, γH2AX assay, and micronucleus (MN) test, considering also iron ion release capacity and alterations in DNA repair ability. Results showed a moderate cytotoxicity related to cell cycle arrest and cell death promotion, regardless of serum presence. O-ION induced genotoxic effects, namely primary DNA damage, as detected by the comet assay and H2AX phosphorylation, but A172 cells were able to repair this particular damage because no chromosome alterations were found (confirmed by MN test results). Accordingly, no effects on the DNA repair ability were observed. The presence of serum proteins did not influence O-ION toxicity. Iron ions released from the O-ION surface seemed not to be responsible for the cytotoxic and genotoxic effects observed. Environ. Mol. Mutagen. 2019. © 2019 Wiley Periodicals, Inc.
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