• An Air-liquid Interface Bronchial Epithelial Model for Realistic, Repeated Inhalation Exposure to Airborne Particles for Toxicity Testing.

      Braakhuis, Hedwig M; He, Ruiwen; Vandebriel, Rob J; Gremmer, Eric R; Zwart, Edwin; Vermeulen, Jolanda P; Fokkens, Paul; Boere, John; Gosens, Ilse; Cassee, Flemming R (2020-05-13)
    • Considerations for Safe Innovation: The Case of Graphene.

      Park, Margriet V D Z; Bleeker, Eric A J; Brand, Walter; Cassee, Flemming R; van Elk, Merel; Gosens, Ilse; de Jong, Wim H; Meesters, Johannes A J; Peijnenburg, Willie J G M; Quik, Joris T K; et al. (2017-10-24)
      The terms "Safe innovation" and "Safe(r)-by-design" are currently popular in the field of nanotechnology. These terms are used to describe approaches that advocate the consideration of safety aspects already at an early stage of the innovation process of (nano)materials and nanoenabled products. Here, we investigate the possibilities of considering safety aspects during various stages of the innovation process of graphene, outlining what information is already available for assessing potential hazard, exposure, and risks. In addition, we recommend further steps to be taken by various stakeholders to promote the safe production and safe use of graphene.
    • Mechanism of Action of TiO: Recommendations to Reduce Uncertainties Related to Carcinogenic Potential.

      Braakhuis, Hedwig M; Gosens, Ilse; Heringa, Minne B; Oomen, Agnes G; Vandebriel, Rob J; Groenewold, Monique; Cassee, Flemming R (2020-04-13)
      The Risk Assessment Committee of the European Chemicals Agency issued an opinion on classifying titanium dioxide (TiO2) as a suspected human carcinogen upon inhalation. Recent animal studies indicate that TiO2 may be carcinogenic through the oral route. There is considerable uncertainty on the carcinogenicity of TiO2, which may be decreased if its mechanism of action becomes clearer. Here we consider adverse outcome pathways and present the available information on each of the key events (KEs). Inhalation exposure to TiO2 can induce lung tumors in rats via a mechanism that is also applicable to other poorly soluble, low-toxicity particles. To reduce uncertainties regarding human relevance, we recommend gathering information on earlier KEs such as oxidative stress in humans. For oral exposure, insufficient information is available to conclude whether TiO2 can induce intestinal tumors. An oral carcinogenicity study with well-characterized (food-grade) TiO2 is needed, including an assessment of toxicokinetics and early KEs. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 61 is January 8, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
    • Quantitative human health risk assessment along the lifecycle of nano-scale copper-based wood preservatives.

      Hristozov, Danail; Pizzol, Lisa; Basei, Gianpietro; Zabeo, Alex; Mackevica, Aiga; Hansen, Steffen Foss; Gosens, Ilse; Cassee, Flemming R; de Jong, Wim; Koivisto, Antti Joonas; et al. (2018-06-12)
      The use of nano-scale copper oxide (CuO) and basic copper carbonate (Cu2(OH)2CO3) in both ionic and micronized wood preservatives has raised concerns about the potential of these substances to cause adverse humans health effects. To address these concerns, we performed quantitative (probabilistic) human health risk assessment (HHRA) along the lifecycles of these formulations used in antibacterial and antifungal wood coatings and impregnations by means of the EU FP7 SUN project's Decision Support System (SUNDS, www.sunds.gd). The results from the risk analysis revealed inhalation risks from CuO in exposure scenarios involving workers handling dry powders and performing sanding operations as well as potential ingestion risks for children exposed to nano Cu2(OH)2CO3 in a scenario involving hand-to-mouth transfer of the substance released from impregnated wood. There are, however, substantial uncertainties in these results, so some of the identified risks may stem from the safety margin of extrapolation to fill data gaps and might be resolved by additional testing. Our stochastic approach successfully communicated the contribution of different sources of uncertainty in the risk assessment. The main source of uncertainty was the extrapolation from short to long-term exposure, which was necessary due to the lack of (sub)chronic in vivo studies with CuO and Cu2(OH)2CO3. Considerable uncertainties also stemmed from the use of default inter- and intra-species extrapolation factors.
    • Toxicity of copper oxide and basic copper carbonate nanoparticles after short-term oral exposure in rats.

      de Jong, Wim H; De Rijk, Eveline; Bonetto, Alessandro; Wohlleben, Wendel; Stone, Vicki; Brunelli, Andrea; Badetti, Elena; Marcomini, Antonio; Gosens, Ilse; Cassee, Flemming R (2018-11-19)
      Copper oxide (CuO) nanoparticles (NPs) and copper carbonate nanoparticles (Cu
    • Transcriptional profiling reveals gene expression changes associated with inflammation and cell proliferation following short-term inhalation exposure to copper oxide nanoparticles.

      Costa, Pedro M; Gosens, Ilse; Williams, Andrew; Farcal, Lucian; Pantano, Daniele; Brown, David M; Stone, Vicki; Cassee, Flemming R; Halappanavar, Sabina; Fadeel, Bengt (2018-03)
      Our recent studies revealed a dose-dependent proinflammatory response to copper oxide nanoparticles (CuO NPs) in rats following short-term inhalation exposure for five consecutive days. Here transcriptomics approaches were applied using the same model to assess global gene expression in lung tissues obtained 1 day post-exposure and after a recovery period of 22 days from rats exposed to clean air or 6 hour equivalent doses of 3.3 mg m-3(low dose) and 13.2 mg m-3(high dose). Microarray analyses yielded about 1000 differentially expressed genes in the high-dose group and 200 in low-dose compared to the clean air control group, and less than 20 after the recovery period. Pathway analysis indicated cell proliferation/survival and inflammation as the main processes triggered by exposure to CuO NPs. We did not find significant perturbations of pathways related to oxidative stress. Upregulation of epithelial cell transforming protein 2 (Ect2), a known oncogene, was noted and ECT2 protein was upregulated in the lungs of exposed animals. Proliferation of alveolar epithelial cells was demonstrated based on Ki67 expression. The gene encoding monocyte chemoattractant protein 1 (or CCL2) was also upregulated and this was confirmed by immunohistochemistry. However, no aberrant DNA methylation of inflammation-associated genes was observed. In conclusion, we have found that inhalation of CuO NPs in rats causes upregulation of the oncoprotein ECT2 and the chemokine CCL2 and other proinflammatory markers as well as proliferation in bronchoalveolar epithelium after a short-term inhalation exposure. Thus, pathways known to be associated with neoplastic processes and inflammation were affected in this model.