Search

Assessment of nanomaterial (NM) induced inflammatory responses has largely relied on rodent testing via measurement of leukocyte accumulation in target organs. Despite observations that NMs activate neutrophil driven inflammatory responses in vivo, a limited number of studies have investigated neutrophil responses to NMs in vitro. We compared responses between the human neutrophil-like HL-60 cell line and human primary neutrophils following exposure to silver (Ag), zinc oxide (ZnO), copper oxide (CuO) and titanium dioxide (TiO2) NMs. NM cytotoxicity and neutrophil activation were assessed by measuring cellular metabolic activity, cytokine production, respiratory burst, and release of neutrophil extracellular traps. We observed a similar pattern of response between HL-60 cells and primary neutrophils, however we report that some neutrophil functions are compromised in the cell line. Ag NMs were consistently observed to stimulate neutrophil activation, with CuO NMs inducing similar though weaker responses. TiO2 NMs did not induce a neutrophil response in either cell type. Interestingly, ZnO NMs readily induced activation of HL-60 cells but did not appear to activate primary cells. Our findings are relevant to the development of a tiered testing strategy for NM hazard assessment which promotes the use of non-rodent models. Whilst we acknowledge that HL-60 cells may not be a perfect substitute for primary cells and require further investigation regarding their ability to predict neutrophil activation, we recommend their use for initial screening of NM-induced inflammation. Primary human neutrophils can then be used for more focused assessments of neutrophil activation before progressing to in vivo models where necessary. [ABSTRACT FROM AUTHOR]

Substantial limitations and uncertainties hinder the exposure assessment of engineered nanomaterials (ENMs). The present deficit of reliable measurements and models will inevitably lead in the near term to qualitative and uncertain exposure estimations, which may fail to support adequate risk assessment and management. Therefore it is necessary to complement the current toolset with user-friendly methods for near-term nanosafety evaluation. This paper proposes an approach for relative exposure screening of ENMs. For the first time, an exposure model explicitly implements quantitative weight of evidence (WoE) methods and utilises expert judgement for filling data gaps in the available evidence-base. Application of the framework is illustrated for screening of exposure scenarios for nanoscale titanium dioxide, carbon nanotubes and fullerenes, but it is applicable to other nanomaterials as well. The results show that the WoE-based model overestimates exposure for scenarios where expert judgement was substantially used to fill data gaps, which suggests its conservative nature. In order to test how variations in input data influence the obtained results, probabilistic Monte Carlo sensitivity analysis was applied to demonstrate that the model performs in stable manner. [ABSTRACT FROM AUTHOR]

In assessing hazard for human health posed by newly engineered nanomaterials (ENM), approaches such as Weight of Evidence (WOE) and expert judgment are required to develop conclusions about the hazard of ENM. This is because all factors affecting hazard are not currently well defined and are often subject to different interpretation. Here we report the application of a WOE procedure to assess the potential of ENM to cause harm for human health, by integrating and combining physicochemical properties of NM and toxicity data obtained within the EU-funded Particle Risk project. The procedure was applied to carbon black (CB), single-walled carbon nanotubes (SWNT), C60 fullerene and quantum dots (QD) ENM tested during the Particle Risk project. The results show that some of the investigated ENM present a relatively higher hazardousness level on the basis of the integration of their physicochemical properties and toxicological effects, and that their hazard may be ranked as follow: QD >> C60 > SWNT > CB. This case study shows the utility of WOE approach to obtain a hazard ranking of ENM. [ABSTRACT FROM AUTHOR]

The authors reflect on the alleged indiscriminate usage of the term "nanoparticles" in the titles of scientific studies and in statements to the press. They examine a study conducted by Song and colleagues regarding the association of nanoparticles to serious cases of occupational lung and pleural injury in China, and explain why the inclusion of the term "nanoparticles" in the title of the paper is misleading. They discuss the implications of the study on issues about nanoparticle toxicity.