Browsing by Author "Pinto, Miguel"
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- An integrative assessment to determine the genotoxic hazard of estuarine sediments: combining cell and whole-organism responsesPublication . Costa, Pedro M.; Pinto, Miguel; Vicente, Ana; Gonçalves, Cátia; Rodrigo, Ana; Louro, Henriqueta; Costa, Maria Helena; Caeiro, Sandra; Silva, Maria JoãoThe application of the Comet assay in environmental monitoring remains challenging in face of the complexity of environmental stressors, e.g., when dealing with estuarine sediments, that hampers the drawing of cause-effect relationships. Although the in vitro Comet assay may circumvent confounding factors, its application in environmental risk assessment (ERA) still needs validation. As such, the present work aims at integrating genotoxicity and oxidative DNA damage induced by sediment-bound toxicants in HepG2 cells with oxidative stress-related effects observed in three species collected from an impacted estuary. Distinct patterns were observed in cells exposed to crude mixtures of sediment contaminants from the urban/industrial area comparatively to the ones from the rural/riverine area of the estuary, with respect to oxidative DNA damage and oxidative DNA damage. The extracts obtained with the most polar solvent and the crude extracts caused the most significant oxidative DNA damage in HepG2 cells, as measured by the formamidopyrimidine-DNA glycosylase (FPG)-modified Comet assay. This observation suggests that metals and unknown toxicants more hydrophilic than polycyclic aromatic hydrocarbons may be important causative agents, especially in samples from the rural part of the estuary, where oxidative DNA damage was the most significant. Clams, sole, and cuttlefish responded differentially to environmental agents triggering oxidative stress, albeit yielding results accordant with the oxidative DNA damage observed in HepG2 cells. Overall, the integration of in vivo biomarker responses and Comet assay data in HepG2 cells yielded a comparable pattern, indicating that the in vitro FPG-modified Comet assay may be an effective and complementary line-of-evidence in ERA even in particularly challenging, natural, scenarios such as estuarine environments.
- Avaliação do potencial citotóxico e genotóxico de contaminantes de sedimentos do Estuário do Sado numa linha celular humanaPublication . Pinto, Miguel; Costa, Pedro M.; Louro, Henriqueta; Costa, Maria Helena; Lavinha, João; Caeiro, Sandra; Silva, Maria JoãoO presente estudo integra-se num projeto mais amplo que visa avaliar o risco ambiental – que inclui os riscos ecológicos e para a saúde humana - associado a este ambiente estuarino contaminado. Em particular, este estudo teve como objetivo caracterizar o potencial citotóxico e genotóxico de sedimentos colhidos em vários locais de pesca do Estuário do Sado numa linha celular humana, tendo em vista uma avaliação de eventuais efeitos nefastos para a saúde humana.
- Human hepatoma cells exposed to estuarine sediment contaminant extracts permitted the differentiation between cytotoxic and pro-mutagenic fractionsPublication . Pinto, Miguel; Costa, Pedro M.; Louro, Henriqueta; Costa, Maria Helena; Lavinha, João; Caeiro, Sandra; Silva, Maria JoãoComplex toxicant mixtures present in estuarine sediments often render contaminant screening unfea- sible and compromise determining causation. HepG2 cells were subjected to bioassays with sediment extracts obtained with a series of progressively polar solvents plus a crude extract. The sediments were collected from an impacted area of an estuary otherwise regarded as pristine, whose stressors result mostly from aquaculture effluents and hydrodynamic shifts that enhance particle deposition. Compared to a reference scenario, the most polar extracts yielded highest cytotoxicity while higher genotoxicity (including oxidative damage) was elicited by non-polar solvents. While the former caused effects similar to those expected from biocides, the latter triggered effects compatible with known pro-mutagens like PAHs, even though the overall levels of toxicants were considered of low risk. The results indicate that the approach may constitute an effective line-of-evidence to infer on the predominant set of hazardous contaminants present in complex environmental mixtures.