Percorrer por autor "Cristovam, Elisabete"
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- Cytotoxic and genotoxic effects of environmental relevant concentrations of bisphenol A and interactions with doxorubicinPublication . Ramos, Carina; Ladeira, Carina; Zeferino, Sofia; Dias, Ana; Faria, Isabel; Cristovam, Elisabete; Gomes, Manuel; Ribeiro, EdnaBisphenol A (BPA) is one of the most widely utilized endocrine disruptors to which humans are exposed, particularity through ingestion. BPA is an aneugenic compound with a putative association to tumorigenesis. Although extensively studied in estrogen-responsive cells, information regarding its effects on cells from the upper gastrointestinal tract exposed to free/active forms of BPA are still scarce. Similarly, BPA interactions with other drugs has been neglected, although it has been suggested to has a potential role in doxorubicin (DOX) chemoresistance. This study is intended to assess potential cytotoxic and genotoxic effects of BPA, as well as its interactions with DOX, in Human epithelial type 2 cells (Hep-2) originated from a human laryngeal carcinoma and in a DNA damage responsive cell line, the human lung fibroblasts (MRC-5). Cell viability was analyzed through the resazurin assay. The G protein-coupled estrogen receptor 1 (GPER) expression was visualized by immunodetection. Genotoxicity, namely DNA damage and oxidative DNA damage, were assessed by comet assay and micronuclei induction, and mitotic disruption was evaluated cytologically by fluorescent microscopy wif DAPI staining. Cytotoxicity analysis showed that exposure to BPA per se does not affect cellular viability. Nevertheless, the genotoxic analysis showed that BPA induced an increase of DNA damage in the Hep-2 cell line and in oxidative damage in the MRC-5 cell line. An increase of micronuclei was also observed in both cell lines following BPA exposure. BPA and DOX co-exposures suggested that BPA acts as an antagonist of DOX effects in both cell lines. The interaction wif DOX appears to be cell type dependent, exhibiting a non-monotonic response curve in MRC-5 cells, a GPER expressing cell line. Our study emphasizes the need for a deeper knowledge of BPA interactions, particularly with chemotherapeutic agents, in the context of risk assessment and public health.
- Cytotoxicity effects of bisphenol A in Hep2 and MRC5 cell lines: is established TDI protective enough?Publication . Ribeiro, Edna; Zeferino, Ana Sofia; Dias, Ana; Cristovam, Elisabete; Viegas, SusanaEndocrine disrupting chemicals (EDCs) are exogenous compounds generally employed in the food and drinks processing and packing, with potential associated hazardous effects for human health. Bisphenol A (BPA) stands out as a paradigmatic xenoestrogen for which human exposure is widespread, omnipresent and persistent, particularly trough ingestion of contaminated food and beverages. European Food Safety Authority (EFSA) experts on the latest comprehensive re-evaluation of BPA exposure and toxicity reduced the tolerable daily intake (TDI) from 50 μg/kg bw/day to 4 μg/kg bw/day. This compound is included in the Priority List of Chemicals within the EU Strategy for Endocrine Disruptors and classified as high concern in terms of human/wildlife exposure. BPA even at very low concentrations can influence cell fate in a cell type specific manner and epidemiological studies have demonstrated positive correlations between BPA levels detected in human biological samples and etiology of numerous pathologies. Here we aimed to evaluate potential cytotoxic effects of BPA concentrations within the range detected in human biological samples consistent to exposure levels below the established TDI, namely 4.4 μM, 4.4 nM and 0.44 nM in Hep2 and MRC5 cell lines. Cytotoxic effects were assessed trough the fluorometric method CellTiter-Blue assay and expression of BPA high affinity receptor GPER, in MRC5 cells, was performed trough immunofluorescence technique. We demonstrate that MCR5 cells express GPER receptor and no significant differences in viability associated with BPA exposure was observed in both cell lines. Our results indicate that BPA concentrations below the EFSA established TDI do not affect Hep2 or MRC5 cellular viability which sustains the indication of safe levels. Nevertheless, further research must be performed in order to assess potential effects that are not reflected by cytotoxicity such as genotoxicity and mixtures interactions.
- Viruses present indoors and analyses approachesPublication . Ribeiro, Edna; Leitão, Maria do Céu; Cristovam, Elisabete; Dias, AnaThrough human history viruses have shown enormous epidemiological and pandemic potential as the occurrence and spread of viruses in pandemic dimensions poses a threat to the health and lives of seven billion people worldwide. Scientific evidence has associated harmful health effects to indoor air hazards recognizing the existence of a vital concern in public health sector. Thus the assessment of human exposure to biological aerosols and droplets indoor became an imperative requirement of the investigation. Environmental bioburden assessment of viruses relies on both culture-dependent approaches that comprise classical methodologies, still prominent and vital in the field of modern biotechnology, and culture-independent approaches based on nucleic acid amplification techniques, which are considered the gold standard in clinical virology. The main factor influencing indoor microbiology is the human being and their activities. Indoor environments to be considered are those regularly occupied by humans: residences, offices, schools, industrial buildings, healthcare facilities, farming activities and other settings occupied all the time, or in which occupant density is high. It’s well known that approximately 60% of total human respiratory and gastrointestinal infections are acquired indoor, since viruses have a rapid spread in the community and can be transmitted easily, especially in crowded and poorly ventilated environments, causing high morbidity and decline in quality of life and productivity. Studies have shown that respiratory syncytial virus, rhinovirus, metapneumovirus, influenza and parainfluenza virus, and human enterovirus infections may be associated with virus-induced asthma, leading to diseases such as pneumonia. Gastroenteritis infectious (about 30±40% of cases) is attributable to viruses. Rotavirus, Astrovirus, Norwalk-like viruses and other caliciviruses are responsible for 48% of all reported outbreaks of infectious intestinal disease. Safe working conditions are essential for healthy living, that’s why the programmes conceived as a result of strategic and preventive policy maintenance, in refrigeration and ventilation systems, are the determining factor for the control of biological pollutants. Moreover, the development of highly sensitive and specific detection and identification methodologies with capacity to be used in diverse applications, such as diagnosis, public health risk assessment, research and for the implementation of preventive measures and protocols are imperative.