Percorrer por autor "Bessa, Maria João"
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- Assessing the in vitro toxicity of airborne (nano)particles to the human respiratory system: from basic to advanced modelsPublication . Bessa, Maria João; Brandão, Fátima; Rosário, Fernanda; Moreira, Luciana; Reis, Ana Teresa; Valdiglesias, Vanessa; Laffon, Blanca; Fraga, Sónia; Teixeira, João PauloSeveral studies have been conducted to address the potential adverse health risks attributed to exposure to nanoscale materials. While in vivo studies are fundamental for identifying the relation-ship between dose and occurrence of adverse effects, in vitro model systems provide important information regarding the mechanism(s) of action at the molecular level. With a special focus on exposure to inhaled (nano)particulate material toxicity assessment, this review provides an over-view of the available human respiratory models and exposure systems for in vitro testing, advan-tages, limitations, and existing investigations using models of different complexity. A brief overview of the human respiratory system, pathway and fate of inhaled (nano)particles is also presented.
- Assessing the in vitro toxicity of engineered and airborne nanoceramics: contribution to the safe production and use of nanomaterials in the ceramic industryPublication . Bessa, Maria João; Fraga, Sónia; Teixeira, João Paulo; Laffon, Blanca LageAdvanced ceramic technologies have a strong potential for airborne (nano)particle formation and emission, meaning that workers of those industries are at great risk of exposure to these particles. However, toxicological data of these (nano)particles is lacking, particularly for airborne particles released within sectors such as the ceramic industry. To address this relevant topic, the present work aimed to assess the toxicity of occupationally relevant doses of industrially process-generated particles emitted during two industrial thermal spraying technologies [atmospheric plasma spraying (APS) and high velocity oxy-fuel (HVOF)], as well as of four engineered nanoparticles [ENP; tin oxide (SnO2), antimony-tin oxide (ATO; Sb2O3●SnO2), cerium oxide (CeO2) and zirconium oxide (ZrO2)] used as raw materials for ceramics manufacture. Two human respiratory in vitro systems, either conventional alveolar epithelial A549 cultures under submerged or air-liquid interface (ALI) conditions, or advanced three-dimensional (3D) upper airway epithelium (MucilAirTM) cultures at ALI were exposed to the selected particles. Major toxicity endpoints including plasma membrane integrity, metabolic activity, oxidative stress, inflammatory response, and genotoxicity were assessed. Overall, the tested process-generated particles seem to be more toxic compared to the ENP, most likely due to their higher chemical complexity and composition [elevated levels of metallic elements like chromium (Cr) and nickel (Ni)]. Among the two evaluated thermal spraying processes, particles derived from HVOF were more cytotoxic than those emitted from APS. Either fine (PGFP) and ultrafine (PGNP) particles from both spraying processes were able to induce measurable genotoxic effects. While APS particles lead to increased levels of histone 2AX (H2AX) phosphorylation, HVOF particles caused 8-oxo-7,8-dihydroguanine (8-oxo-G) oxidative DNA lesions. ENP were more toxic to human alveolar epithelial cultures when aerosolised than in liquid suspension, particularly ZrO2 NP. On the other hand, advanced MucilAirTM cultures, that better mimic in vivo physiological features, such as the mucociliary defence mechanisms, were quite resistant to both HVOF-derived particles and ENP aerosols. Thus, while 3D human upper airway epithelial cultures exhibited attenuated responses, the conventional A549 cultures were more sensitive to the studied (nano)particles.The present work highlights the hazard of industrially derived (nano)particles, either intentionally used or incidentally released into the workplace air during advanced ceramic processes. Importantly, particles’ physicochemical properties alongside the testing conditions (cell model and type of exposure) played a determinant role in the observed biological responses. These findings reinforce the importance of using physiologically relevant in vitro models in (nano)particle toxicity studies, for better data extrapolation to humans.
- Assessment of Beneficial and Possible Toxic Effects of Two New Alfalfa-Derived Shelf ProductsPublication . Soto-Zarazúa, María; Bah, Moustapha; García-Alcocer, María; Berumen, Laura; Costa, Carla Sofia; Bessa, Maria João; Rodrigues, Francisca; Teixeira, João Paulo; Oliveira, Maria BeatrizAerial parts of Medicago sativa L. have been used as food and its consumption has been associated with health benefits, one among the most important being menopausal symptoms control. This work was aimed to explore possible pharmacological effects of two new alfalfa-derived products that have recently emerged as daily beverage preparations. In exploring their potential estrogenic effects, they produced no relevant alteration in the uterus. However, lowering glucose levels until normal values without causing further hypoglycemic effect were observed, when rats were treated with 1.5 g/kg/day samples. In vivo acute toxicity was not found when the alfalfa products were tested up to 3 g/kg rat weight. Furthermore, in vitro studies were conducted to assess their possible toxic effects. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase tests were carried out on the Caco-2 cell model to determine cell viability and membrane integrity. A concentration-dependent effect was observed, with a significant decrease in cell viability after exposure to concentrations of alfalfa product up to 100 mg/mL (after 3 h of incubation) and 50 mg/mL (after 24 h of treatment). Although in vitro level, the decrease in cell viability at these still low doses may underlie some toxicity, making necessary additional studies before any recommendation of a sustained consumption of these products by humans.
- 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.
- Azadirachta indica A. Juss (neem) phenolic extract inhibits human B-lymphoblastoid cells growth via cell cycle arrest, apoptosis induction, and DNA damagePublication . Santos, Klebson Silva; Costa, Carla; Bessa, Maria João; Teixeira, João Paulo; Muniz, Ana Veruska Cruz da Silva; Padilha, Francine Ferreira; Dariva, Cláudio; Oliveira, Maria Beatriz Pinto PriorAim: As far as is known, the pharmaceutical effects of neem on human B-lymphoblastoid (TK6) cells have not been studied until now. Hence, the present study aimed to obtain neem phenolic extracts for inhibits the proliferation of TK6 cells and explore some possible underlying mechanisms involved in these effects. Methods: Hexane extract (HE) was obtained in the first step. After that, the residual hexane was removed from the neem. The dried neem sample was used in a new extraction for obtaining the ethyl acetate extract (EAE). Total phenolic compounds (TPC) and total flavonoid contents (TFC) were determined by spectrophotometric methods. Lactate dehydrogenase (LDH) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) tests were used to evaluate the cytotoxicity in TK6 cells. The stop at G0/G1 cell cycle and inducing apoptosis in the TK6 cells were analyzed by flow cytometry. For deoxyribonucleic acid (DNA) damage evaluation, the alkaline comet test was used. Results: The higher TFC (65.50 mg/g of extract ± 1.17 mg/g of extract) and TPC (52.08 mg of extract ± 0.88 mg of extract) were obtained in EAE compared to HE that was obtained TFC of 14.61 mg/g of extract ± 0.60 mg/g of extract and TPC of 3.20 mg/g of extract ± 1.20 mg/g of extract. EAE was more significantly cytotoxic to TK6 cells than HE. The apoptosis induction was higher after exposure to 15.0 µg/mL of EAE (11.29%) in comparison to 15.0 µg/mL of HE (2.52%). The G0/G1 phase increased from 72% negative control (NC) to 83% after treatment with neem extracts (15 µg/mL). Neem extracts were also able to cause DNA strand breaks in TK6 cells. Conclusions: The extraction residue from neem leaf after hexane extraction is a source important of cytotoxic and genotoxic molecules against TK6 cells, the results also can suggest that the toxic effects in TK6 cells can be provided most likely due to the presence of high content of TPC from neem extracts.
- Cytotoxic effects of single and binary mixtures of metal oxide nanoparticles and metal(loid) on A549 human cell line.Publication . Rosário, Fernanda; Bessa, Maria João; Brandão, Fátima; Costa, Carla; Lopes, Cláudia B.; Estrada, Ana Cristina; Tavares, Daniela S.; Teixeira, João Paulo; Reis, Ana TeresaBackground, Motivation and Objective: The need to assess the toxicity resulting from exposure to mixtures of chemicals has been recognized by the WHO and EU, as humans are simultaneously exposed to an array of natural and anthropogenic contaminants. Of particular interest are the potential combined effects resulting from interaction of nanoparticles (NPs) and metals. While the first are the current driving force for emerging contaminants, the latter, as legacy contaminants, remain a concern. Metals show strong affinity to NPs, which can change the uptake and toxicity to the organism of each individual contaminant. Studying the effects on the respiratory tract is of upmost relevance because of its constant contact with xenobiotics, resulting in adverse effects on the lung. Considering the above, the objective of this work was to assess and compare viability, cell cycle, and uptake of A549 cells after exposure to single and binary mixtures of titanium dioxide nanoparticles (TiO2NP), cerium oxide nanoparticles (CeO2NP), arsenic (As) and mercury (Hg). These chemicals were chosen because: 1) TiO2NP are among the most abundantly used NPs; 2) CeO2NP have been used in nanomedicine for its high biocompatibility and cytoprotective effect; and 3) As and Hg due to their non‐biodegradable, persistent, and extremely toxic character. This work intends to support adequate human risk assessment resulting from co-exposure to multiple contaminants.
- Cytotoxicity and DNA damage of a panel of manufactured nanomaterials in rat alveolar epithelial RLE-6TN cellsPublication . Brandão, Fátima; Fraga, Sónia; Costa, Carla; Bessa, Maria João; Haase, Andrea; Teixeira, João PauloMain goal: The aim of this study was to evaluate the cyto- and genotoxicity of a panel of MNMs, including SiO2 NPs, graphene oxide, and nano-sized pigments in rat alveolar epithelial cells (RLE-6TN), a primary target following inhalation exposure.
- Cytotoxicity of Clay-TiO2 nanostructures in human HepG2 cellsPublication . Bessa, Maria João; Reinosa, Julian Jimenez; Fernandez, José Francisco; Banares, Miguel; Teixeira, João Paulo; Costa, CarlaBackground and Objective: In the last decades, nanotechnology has become increasingly attractive to different scientific and industrial fields as it becomes evident that manufactured nanomaterials offer a whole new range of potentialities. On the other hand, different studies have been showing that nanomaterials can be toxic and therefore may harm both the environment and the human health. Recent advances in the production of nanomaterials lead to the development of new structures, namely of nanoparticles immobilized in microstructures that by presenting new physico-chemical features must be test in regards to their toxic potential. Therefore, the aim of the present work was the evaluation of the in vitro cytotoxicity of TiO2 nanoparticles (TiO2 NPs) immobilized in clay (C-TiO2 ) in a hepatocellular carcinoma human cell line (HepG2). In order to understand the origin of the observed effects, TiO2 NPs and clay alone were also studied.
- A first insight into the genotoxicity induced on A549 human cell line by titanium and cerium dioxide nanoparticles co-exposed with arsenic and mercuryPublication . Vilaça, Cláudia; Rosário, Fernanda; Bessa, Maria João; Ribeiro, César; Costa, Carla; Teixeira, João Paulo; Reis, Ana TeresaObjectives: Nanogenotoxicity studies traditionally consider exposure to a single NP. However, potential genotoxicity resulting from exposure to mixtures of NP and other contaminants cannot be neglected; This work will constitute the first insight into the DNA damage induced on A549 cells by exposure to binary mixtures of titanium (TiO2) and cerium (CeO2) dioxide, and highly toxic metals arsenic (As) and mercury (Hg).
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