Percorrer por autor "Tavares, A.M."
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- Evaluation of combined cytotoxic effects of effects of ochratoxin A and fumonisina B1 in human liver and renal cellsPublication . Tavares, A.M.; Mendonça, I.; Alvito, Paula; Loureiro, S.; Louro, Henriqueta; Silva, MariaMycotoxins are fungal food contaminants with potential to cause severe acute and chronic conditions1. Therefore, food contamination with mycotoxins such as ochratoxin A (OTA) and fumonisin B1 (FB1) causes great concern. Previous studies addressed the co-occurrence of these toxins in foods2, however there is little knowledge on their combined cytotoxic effects. In the present study we aimed to evaluate the cytotoxic effects of mixtures of OTA and FB1 in two human-derived cell lines.
- Interlaboratory Validation of the Cell Transformation Assay (CTA) for Carcinogenic Assessment of BPA AlternativesPublication . El Yamani, N.; Aimonen, K.; Dusinska, M.; Guichard, Y.; Honza, T.; Louro, H.; Pereira, M.J.; Rundén-Pran, E.; SenGupta, T.; Tavares, A.M.; Silva, M.J.Bisphenol A (BPA) has long been used in various plastic products, resins and coatings, making human exposure to this chemical inevitable. Due to its harmful health effects, including endocrine disruption, and immunotoxicity, BPA has been increasingly replaced by several alternative compounds. However, there are still significant gaps in research regarding the safety of these BPA alternatives, particularly concerning their potential carcinogenicity. One of the in vitro assays to assess carcinogenic potential of chemicals is the Bhas-42 cell transformation assay (CTA). The assay can detect both genotoxic and non-genotoxic carcinogens It is valuable in identifying potential cancer risks before widespread exposure occurs, contributing to the development of safer chemicals and products, as well as better regulatory standards while adhering to the 3R concept. The EU-Partnership for the Assessment of Risks from Chemicals (PARC) project is addressing these research gaps to enhance the risk assessment of BPA alternatives. BPA and some alternatives, including BPZ, BPE, BPAP, BPA-MAE, BPP, and TCBPA, were selected for evaluation of their carcinogenic potential using the in vitro 2-stage Bhas-42 CTA. A key objective of the project is to validate the CTA as a reliable in vitro method for assessing carcinogenicity. To ensure consistency and accuracy across participating labs, an interlaboratory comparison was initiated and a standardized SOP was developed, including concentration ranges for controls and BPA analogues, in alignment with OECD guidance document. The first results from the protocol harmonization, using the selected controls, were consistent across all participating labs. BPA and its analogues are being tested, and the results are under evaluation. The data generated will contribute to the overall weight of evidence on the hazards posed by these chemicals and, when combined with findings from other endpoints, will provide a solid basis for refining their regulation.
- The effects of matrix proteins on the aflatoxin M1 bioaccessibility and the Caco-2 intestinal transportPublication . Tavares, A.M.; Egge, L.; Portmann, R.; Alvito, PaulaMycotoxins are fungal natural contaminants commonly found in food products that cause severe effects in human health, especially children. The mycotoxins occur in a great variety of foods, and can form complexes with the food matrix with a significant impact on their bioaccessibility. The bioaccessible fraction of the food contaminant contributes to the effective internal exposure depending on the contamination level, food matrix and the way the food is contaminated (spiked or naturally). To our knowledge, until now no studies were performed to disclose the possible role of milk proteins in the bioaccessibility of aflatoxin M1 (AFM1), a mycotoxin commonly found in milk products. On behalf of a Short Term Scientific Mission within the Infogest COST action and of the project Mycomix (FCT, Portugal), a collaboration study between the National Health Institute Doutor Ricardo Jorge (Portugal) and Agroscope Liebefeld- Posieux (Switzerland) was established. The recently submitted harmonized in vitro digestion protocol2 was for the first time applied to study the bioaccessibility of AFM1 in artificially contaminated infant formula and the protein profile of the samples analysed by LC-MS/MS. The results revealed a good performance of the harmonized method, showing a successful digestion of the proteins into smaller peptides. However, the presence of aflatoxin M1 contamination was not detected before and after digestion, suggesting an interaction with the food matrix. Moreover, in the transport assays, the presence of AFM1 did not impair the Caco-2 cells membrane integrity as shown by the Transepithelial Electrical Resistance. Further assays including an optimized AFM1 extraction method are in progress to evaluate toxin bioaccessibility and its presence in basolateral, apical cell media and cell cytoplasm.