Browsing by Author "Bettencourt, Ana F."
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Biological effects of ingested nanomaterials and potential adverse outcomes for human healthPublication . Vieira, Adriana; Gramacho, Ana Catarina; Rolo, Dora; Vital, Nádia; Pereira, Joana; Matos, Paulo; Jordan, Peter; Martins, Carla; Assunção, Ricardo; Alvito, Paula; Gonçalves, Lídia; Bettencourt, Ana F.; Silva, Maria João; Louro, HenriquetaThe technology based on manufactured nanomaterials (NMs) has been pointed as key enabling technology, due to its potential to improve many products and processes, namely in agriculture, food and feed industry, leading to an exponential growth. Many products, already available, have NMs, such titanium dioxide NMs used as food additives, and many others are in development. Oral exposure may occur either directly, through the consumption of products/pharmaceuticals containing NMs, or indirectly, through the ingestion of foods contaminated with NMs released from food-contact materials or even through concentration in the food chain due to environmental accumulation. Therefore, the gastrointestinal tract appears to be a probable route of exposure to NMs and may lead to systemic exposure if the body barriers are surpassed. One major concern for public health is that NMs may produce biological effects, such as genotoxicity that are associated with increased risk of cancer. Although NMs have been extensively investigated in recent years, the studies have generated contradictory results, possibly due to differences in the physicochemical properties of the NMs studied and to other variables in the test systems. This work aimed to investigate the nano-bio interactions of titanium dioxide NMs, at cellular and molecular level, in the context of intestinal tract and digestion processes, to better understand their potential adverse impacts on human health. The results of the NMs uptake by intestinal cells, as well as their cytotoxic and genotoxic effects will be presented. This nanotoxicology approach may be incorporated at early-stage in the development of new NMs for food industry, in a “safe-by-design” approach that will enable safety to keep pace with innovation.
- Cellular, Molecular and Genotoxic Effects of Digested Titanium Dioxide NanomaterialsPublication . Rolo, Dora; Pereira, Joana F.S; Vieira, Adriana; Roque, Rossana; Gramacho, Ana Catarina; Vital, Nádia; Matos, Paulo; Gonçalves, Lídia; Bettencourt, Ana F.; Silva, Mafalda A.; Martins, Carla; Assunção, Ricardo; Alvito, Paula; Jordan, Peter; Silva, Maria João; Louro, HenriquetaHuman exposure to titanium dioxide nanomaterials(TiO2NMs) occurs particularly by ingestion, due to food/food contact materials and consumer products. However, the possibility of adverse effects in gastrointestinal tract is unclear. Aiming to study the impact of digestion on the NMs’ properties and their cellular/molecular effects, two human intestinal cell lines were used, Caco-2 and HT29-MTX-E12. After exposure to TiO2NMs(NM-102, NM-103, NM-105), undigested or subjected to standardized static in vitro digestion method (mimicking human digestion), the cells were analyzed for toxicity, genotoxicity, reactive oxygen species, NM uptake and intestinal translocation. We showed that in vitro digestion of TiO2NMs may increase their toxicity and DNA-damaging effect, depending on the NM, more relevant for the rutile/anatase NM-105, possibly due to its smaller hydrodynamic size in the cellular medium. Effects on chromosomal integrity were seen in HT29-MTX-E12 cells, for all tested TiO2NMs, especially after digestion. Internalization into early endosomes was confirmed for NM-103 and NM-105, before and after digestion, in monolayers of both cell lines, and at the apical membrane of polarized Caco-2 cells. The internalized NMs accumulated in late endosomes/multivesicular bodies, partially transversing the basolateral membrane of polarized Caco-2 cells without changing transepithelial electrical resistance or epithelial marker abundance. These results suggest that part of the TiO2NMs can be transcytosed through colonic epithelia without disrupting intestinal barrier integrity. Overall, the biological outcomes from TiO2NMs interaction with intestinal cells were more pronounced after digestion, highlighting its relevance in the hazard assessment of ingested NMs.
- Investigation of the genotoxicity of digested titanium dioxide nanomaterials in human intestinal cellsPublication . Vieira, Adriana; Rolo, Dora; Vital, Nádia; Martins, Carla; Assunção, Ricardo; Alvito, Paula; Gonçalves, Lídia; Bettencourt, Ana F.; Silva, Maria João; Louro, HenriquetaAbout Investigation of the genotoxicity of digested titanium dioxide nanomaterials in human intestinal cells
- Nano-bio interactions of titanium dioxide nanomaterials in the intestinal moiety after simulated digestion in vitroPublication . Louro, Henriqueta; Rolo, Dora; Gramacho, Ana C.; Pereira, Joana; Matos, Paulo; Jordan, Peter; Martins, Carla; Assunção, Ricardo; Alvito, Paula; Gonçalves, Lídia; Bettencourt, Ana F.; Silva, Maria JoãoThe exponential development of nanomaterials (NMs) contrasts with insufficient risk assessment for human health and the environment, leading to concerns for public health. Their potential to improve many products and processes, namely in agriculture, food and feed industry, has led to increased use of NMs, such as titanium dioxide nanomaterials (TiO2). In fact, oral exposure to TiO2 may occur either directly, through the consumption of products/pharmaceuticals containing NMs, or indirectly, through the ingestion of food/water contaminated due to environmental accumulation. Therefore, the gastrointestinal tract (GIT) appears to be a probable route of exposure to NMs and may lead to systemic exposure if the body barriers are surpassed. Since NMs primary physicochemical properties may define nano-bio interactions1, NMs with the same chemistry but with different shape, diameter, length, surface charge or functionalization may lead to different toxicities. Conversely, since the GIT is chemically and physically complex, ingested NMs will pass through different environments prior to their intestinal uptake, affecting their physicochemical properties, so that these secondary physicochemical properties should be considered while evaluating their safety in the food chain. The aim of this work was to investigate the nano-bio interactions of three TiO2 (NM-102, NM-103, NM-105, from Joint Research Centre, Ispra) in the context of intestinal tract and digestion processes. As alternative to animal testing, an in vitro harmonized digestion method2 was used for simulating the human digestion of NMs and their characteristics were studied in acellular and intestinal (Caco-2) cells context. The NMs were characterized using dynamic light scattering (DLS, for size distribution), electrophoretic light scattering (zeta potential), transmission electron microscopy (TEM) for morphological characterization and X-ray energy dispersive spectrometry (EDS) for elemental chemical analysis. TiO2 samples were labelled directly with a fluorescent probe and used for uptake studies with confocal microscopy (CM). In parallel, a co-culture model of Caco-2 with mucous-secreting HT29-MTX was initiated and exposed to TiO2 to ascertain epithelial barrier translocation. The results did not show major differences in the NMs’ pH, osmolality, charge signal or mean size, except for NM-103. TEM and TEM –EDS analysis showed that it is possible to identify primary particles after digestion process and preliminary CM results suggest that some of the tested TiO2 nanomaterials can be uptake by the cells, suggestive of potential subcellular effects that warrant further investigation. References [1] H. Louro, A. Saruga, J. Santos, M. Pinhão, M.J. Silva, Toxicol. In Vitro. 56 (2019)172–183. [2] A. Brodkorb, L.Egger, M. Alminger, P. Alvito et al. Nat Protoc. 2019 Apr;14(4):991-1014.