DGH - Apresentações orais em encontros nacionais
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- Classification of microcytic anemias using machine learning methodsPublication . Neves Leitão, Beatriz; Vinga, Susana; Faustino, PaulaA prevalência mundial da anemia é estimada em 24,8% e de entre as suas possíveis causas sobressaem a carência nutricional em ferro (anemia ferropénica) e algumas doenças genéticas (hemoglobinopatias como, por exemplo, beta-talassémia e alfa-talassémia). O diagnóstico da etiologia das anemias microcíticas requer métodos laboratoriais caros e morosos, mas é fundamental para a decisão clínica referente ao tratamento e, quando apropriado, para o aconselhamento genético. Neste trabalho aplicaram-se algoritmos de aprendizagem automática (machine learning) para diferenciação das referidas anemias microcíticas usando apenas as informações obtidas no hemograma, um dos exames laboratoriais mais comuns em medicina. Os resultados destacaram o excelente desempenho dos classificadores desenvolvidos com o algoritmo de florestas aleatórias (random forests), tanto na classificação binária quanto na multiclasse, demonstrando o potencial da inteligência artificial na identificação da etiologia dessas anemias.
- Genotoxic effects of Alternaria mycotoxins in human liver HepG2 cellsPublication . Ventura, Célia; Vilela, Rita Sofia; Guerreiro, Beatriz; Louro, Henriqueta; Silva, Maria JoãoObjective: Mycotoxins are natural toxic compounds produced by filamentous fungi as secondary metabolites. Human exposure to mycotoxins occurs predominantly through ingestion of contaminated food, and have been associated with nephrotoxicity, hepatotoxicity, immunotoxicity, carcinogenicity, and teratogenicity. Alternaria mycotoxins are produced by black moulds of the genus Alternaria, which are common plant pathogens and saprophytes widely distributed in the environment. However, limited toxicological data exists on Alternaria mycotoxins. Within the scope of the European Partnership for the Assessment of Risks from Chemicals (PARC; https://www.eu-parc.eu/) these toxins were considered as priority substances, and several studies are underway with the aim of filling knowledge gaps regarding their genotoxicity, among other toxic effects. Methods: Genotoxicity was evaluated using the In Vitro Mammalian Cell Micronucleus Assay with cytokinesis block (CBMN) according to the OECD TG 487. HepG2 liver cells were exposed for 48 h to a concentration-range of each Alternaria mycotoxin following dose-range finding based on cytotoxicity testing (MTT assay). Vinblastine was used as a positive control. Results: All tested mycotoxins were cytotoxic in the MTT assay and genotoxic in the CBMN assay. In addition to the significant increase in micronucleated binucleated cells, some mycotoxins also induced a significant increase in other nuclear anomalies in HepG2 cells, showing a dose-response relationship. Conclusions: These results indicate that the studied Alternaria mycotoxins induce chromosomal damage, which can lead to genomic instability, a key driver in cancer. Therefore, this study contributes to PARC objectives, providing critical toxicological data for their hazard assessment following human oral exposure. The data will contribute to support their risk assessment and management by regulators and policy makers in order to protect human health from these emerging food contaminants.
- Impact of nanocelluloses on genome-wide DNA methylation pattern of human pulmonary and intestinal cellsPublication . Ventura, Célia; Vital, Nádia; Valente, Ana; Vieira, Luís; Louro, Henriqueta; Silva, Maria JoãoObjective: Nanocellulose is an innovative nanomaterial with interesting physicochemical properties for several industrial and biomedical applications and its safety for human health must be ensured. This study aimed to identify DNA methylation changes in human pulmonary and intestinal cells after exposure to two fibrillar celluloses with different physicochemical properties, both derived from Eucaliptus globulus. Their cellular effects were investigated in silico by functional pathway and gene ontology (GO) analysis. Methods: We applied Reduced Representation Bisulfite Sequencing to analyze the methylation differences in DNA CpG-rich regions from human bronchial (BEAS-2B) and intestinal (Caco-2) cells exposed for 24h to 14.3 µg/mL of cellulose nanofibrils (CNF) or microfibrils (CMF) versus non-exposed ones. A bioinformatics pipeline was implemented for identifying differentially methylated genes (DMGs), functional pathways, and GO associations. Results: CNF and CMF exposure resulted in 11 and 14 DMGs, respectively, in BEAS-2B cells, 6 being common to both nanocelluloses. In Caco-2 cells, 36 and 31 DMGs were identified, sharing 12 DMGs. No DMGs were shared between these cell lines. Hypomethylation predominated in BEAS-2B cells, and hypermethylation in Caco-2 cells. In BEAS-2B cells, both nanocelluloses affected similar pathways and GO terms (e.g., regulation of DNA replication, damage repair and senescence, telomere maintenance, and D-glucose transport). In Caco-2 cells, both CNF and CMF enriched, for instance, signal transduction, glycosylation, and cytoskeletal dynamics. Each nanocellulose type also affected other different pathways and terms. Conclusions: Nanocellulose may have a wide impact on the metabolism and survival of pulmonary and intestinal cells through several regulatory pathways, which depend on nanocellulose physicochemical properties. Cell type also influences the outcome, suggesting tissue-specific effects. These findings highlight the relevance of DNA methylation in nanotoxicology, providing insights into underlying molecular mechanisms of action. Keywords: gene ontology; nanomaterial; pathway analysis; RRBS
- Rastreio neonatal da drepanocitose: prevalência ao nascimento de 1: 2 381 RNPublication . Rodrigues, Diogo; Marcão, Ana; Lopes, Maria de Lurdes soares; Guimarães, Fábio; Vilarinho, LauraIntrodução e Objetivos: A drepanocitose é uma das patologias monogénicas mais comuns e graves a nível mundial, sendo atualmente considerada um problema de saúde pública na Europa. Trata-se de uma doença hereditária, com transmissão autossómica recessiva, na qual os doentes apresentam uma variante estrutural anormal de hemoglobina – HbS. Com este trabalho pretendemos apresentar a prevalência ao nascimento da drepanocitose em Portugal. Metodologia: Foram rastreados para a drepanocitose 324 077 Recém-Nascidos (RN), em duas fases distintas: Fase I (05/2021 - 01/2022) 24 130 RN exclusivamente dos distritos de Lisboa e Setúbal; Fase II (02/2022 - 07/2025) 299 947 RN de todo o Português. O perfil de hemoglobinas foi estudado pelo método da eletroforese capilar, a partir de amostras de sangue seco colhidas em cartão de Guthrie, entre o 3.º e o 6.º dia de vida do RN. Resultados: No total foram identificados 152 casos de drepanocitose dos quais 135 eram homozigóticos (HbSS) e 17 heterozigóticos compostos (HbSC). Todos os doentes foram reportados a um Centro de Tratamento (CT) para confirmação e avaliação clínica. A prevalência ao nascimento de drepanocitose no nosso país é de 1:2 381 RN. Além do casos de drepanocitose, foram também identificados e reportados para CT mais 15 casos de outras hemoglobinopatias: 3 β-talassémia major, 8 HbEE, 3 HbCC e 1 HbDD. Conclusões: Estes resultados evidenciam a crescente prevalência da drepanocitose em Portugal, alinhando-se com o panorama europeu, e que parece dever-se aos fluxos migratórios mais recentes. A inclusão do rastreio neonatal da drepanocitose no painel de doenças do Programa Nacional de Rastreio Neonatal, em 2023, comprova a importância desta patologia no nosso país.