Effect of size continuum from nanoplastics to microplastics on marine mussel Mytilus edulis: Comparison in vitro/in vivo exposure scenarios

International audienceFor several decades, plastic has been a global threat in terms of pollution. Plastic polymers, when introduce in the aquatic environment, are exposed to fragmentation processes into microplastics (MPs) and nanoplastics (NPs) which could potentially interact with living organisms. The objective of this work was to study the effects of plastic particles representative of those found in the environment, on the marine mussels Mytilus edulis, under two exposure scenarii: in vivo and in vitro. Whole mussels or cultured hemocytes were exposed for 24 hours to NPs and MPs generated from macro-sized plastics collected in the field, but also to reference NPs, at concentrations found in the environment: 0.08, 10 μg and 100 μg.L-1. Results showed that immune response was only activated when mussels were exposed in vivo. However, cytotoxicity (hemocyte mortality) and genotoxicity (DNA damage) parameters were induced after both types of exposure, but in a dose-dependent manner after in vitro hemocyte exposure to all tested plastic conditions. These results indicate that in vitro approaches could be considered as potential predictors of in vivo exposures

Hétérogénéité tumorale des cancers du sein

International audienceThe objective of this literature review is to describe the types of tumor heterogeneity in breast cancer and their clinical implication. Two kinds of tumor heterogeneity are described: intertumor heterogeneity and intra-tumor heterogeneity. In breast cancer, inter-tumor heterogeneity was best characterized in the 2000s thanks to high throughput analyses. These analyzes resulted in a molecular classification of breast cancers distinguishing four subtypes: Luminal A, Luminal B, HER 2+ and basal like. This variability may be observed between the primary tumor and metastases, namely the temporal intratumor heterogeneity. The average discrepancy for the progesterone receptor, estrogen, and between HER2 status appears to be 33%, 20% and 8%, respectively. It is then interesting to study the heterogeneity within the primary tumor: this spatial intra-tumor heterogeneity is poorly known. Physiopathology of intra-tumor heterogeneity light be deciphered by studies on cancer stem cells and clonal evolution model. In addition, the tumor microenvironment seems to actively contribute to this heterogeneity. The major interest to study this heterogeneity is the clinical implication that could result. While precision medicine is emerging, it is important to capture the heterogeneity of each specific tumor type. These new biological knowledge will allow us to anticipate such heterogeneity and individualize the management of breast cancer. Copyrigh

Efficacité des « seuils » dans la prise en charge des cancers de l'ovaire: revue de la littérature

International audienceObjective The "Institut national du cancer" has established since 2007 a minimum threshold of 20 patients per year per center to treat patients with gynecologic cancer. This review aims to assess whether the literature data validate this approach, and specifically for ovarian cancer. Methods A search of the MEDLINE database was conducted, to reference all relevant articles evaluating one hand the links between the survival of patients with ovarian cancer and the average volume of patients per center and by operator; and secondly the relationship between quality of oncological surgery and these volumes. Results Nineteen studies met our inclusion criteria; seventeen were retrospective and two were prospective; population samples ranged from 476 to 96,802 patients. The most important data, quantitatively and qualitatively, concern the evaluation of survival based on the average volume per center, with 8 out of 13 studies finding a statistically significant correlation between average volume per center and survival. Data on the quality of surgery are less abundant and more heterogeneous, depending on the definition of the "optimal" surgery by the authors. Conclusion The establishment of threshold centers appears to be an effective way to improve survival in ovarian cancer. However, these thresholds would have to be specific to ovarian cancer and not extended to "gynecological cancers.

Toxicity assessment of environmental MPs and NPs and polystyrene NPs on the bivalve Corbicula fluminea using a multi-marker approach

International audienceSmall plastic particles, microplastics (MPs) and nanoplastics (NPs) represent a major threat in aquatic environments. Freshwater organisms are exposed to MPs and NPs, particularly in industrial and urban areas. The present study aimed to compare the toxicity between polystyrene NPs (PS NPs) and environmental microplastics (ENV MPs) and nanoplastics (ENV NPs) generated from macro-sized debris collected in the Garonne River on the freshwater bivalve C. fluminea. The organisms were exposed to the different plastic particles at three environmentally relevant concentrations: 0.008, 10, and 100 μg L−1 for 21 days. The biological responses of organisms were assessed using a multi-biomarker approach from the sub-individual to the individual level. The results demonstrated that: i) ENV NPs triggered more effects on detoxification processes and immune response, confirming that using manufactured NPs for laboratory exposure can lead to misleading conclusions on the risks posed by plastic particles; ii) effects of ENV MPs were less marked than ENV NPs, emphasizing the importance of testing a size continuum of plastic particles from NPs to MPs; iii) some effects were only observed for the low and/or intermediate concentrations tested, underlining the importance of using environmentally relevant concentrations. In light of these results, laboratory studies should be continued by exposing aquatic species to environmental MPs and NPs. The properties of these particles have to be characterized for a better risk assessment of environmental plastic particles

Continuum from microplastics to nanoplastics: effects of size and source on the estuarine bivalve Scrobicularia plana

International audiencePlastic has been largely detected in estuarine environments and represents major concern towards aquatic living organisms. The present study evaluates the impact of microplastics (MPs) and nanoplastics (NPs) under realistic exposure conditions. Scrobicularia plana individuals were exposed to low concentrations (0.008, 10, and 100 µg L−1) of environmental MPs and NPs as well as to standard PS NPs, as a comparison condition. The aim of this study was to understand the ecotoxicological effects of environmental plastic particles on S. plana gills and digestive glands but also to compare the effects of plastic polymers size in order to highlight if the size could induce different toxicity profiles within this model organism, at different levels of biological organization. Results showed a differential induction of detoxification enzymes (CAT, GST), immunity (AcP), DNA damage processes as well as a differential effect on behavior and condition index of animals depending upon the type of plastic, the size, the concentration tested, and the type of organ. This study underlines the necessity of testing (i) plastics collected from the environment as compared to standard ones and (ii) the effect of size using plastics coming from the same batch of macrosized plastics. This study concludes on the future need directions that plastic-based studies must take in order to be able to generate a large quantity of relevant data that could be used for future regulatory needs on the use of plastic

Direct and trophic exposure of polystyrene and environmental nanoplastics on Corbicula fluminea

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Toxicity of Environmental and Polystyrene Plastic Particles on the Bivalve Corbicula Fluminea: Focus on the Molecular Responses

International audienceMicroplastics (MPs) and nanoplastics (NPs) are major ecotoxicological concerns in aquatic environments. Among aquatic organisms, filter feeders are particularly exposed to the ingestion of MPs and NPs, filtering large quantities of water for food and having an unselective feeding strategy. The present study investigates the effect of environmental microplastics (ENV MPs) and nanoplastics (ENV NPs) generated from macro-sized plastic debris collected in the Garonne River (France), and polystyrene NPs (PS NPs) on the freshwater bivalve Corbicula fluminea (Müller 1774). The organisms were exposed to each type of plastic particle at three concentrations: 0.008, 10 and 100 μg L−1 for 21 days. Gene expression measurements were conducted in gills and visceral mass at 7 and 21 days to assess the effects of plastic particles on different functions (endocytosis, detoxication, respiratory chain, oxidative stress, immunity, apoptosis and neurotoxicity). Our results revealed that: i) an up-regulation of genes, mainly involved in endocytosis, oxidative stress, immunity, apoptosis and neurotoxicity, was observed at 7 days of exposure for almost all environmental plastic particles and at 21 days of exposure for PS NPs in the gills, ii) PS NPs at the three concentrations tested and ENV MPs at 0.008 μg L−1 induced strong down-regulation of genes involved in detoxication, oxidative stress, immunity, apoptosis and neurotoxicity at 7 days of exposure in the visceral mass whereas ENV MPs at 10 and 100 μg L−1 and all ENV NPs induced less pronounced effects, iii) overall, PS NPs and ENV MPs 0.008 μg L−1 did not trigger the same effects as ENV MPs 10 and 100 μg L−1 and all ENV NPs, either in the gills or the visceral mass at 7 and 21 days of exposure. This study highlighted the need to use MPs and NPs sampled in the environment for future ecotoxicological studies, compared to manufactured PS NPs as their properties (composition, size distribution, surface charge, additive and adsorbed contaminants) induce different effects at the molecular level to living organisms

Direct and trophic exposure of polystyrene and environmental nanoplastics on Corbicula fluminea

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Effect of an environmental microplastic mixture from the Seine River and one of the main associated plasticizers, dibutylphthalate, on the sentinel species Hediste diversicolor

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