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Plenty of new approach methodologies (NAMs) for risk assessment have been developed but only some are included in OECD Test Guidelines (TGs) for regulatory implementation. Nevertheless, NAMs are increasingly applied, e.g. for nanomaterial (NM) risk assessments. The EFSA Guidance on NM risk assessment suggests that NAM‐derived data concerning degradation/dissolution (in relevant biofluids), intestinal uptake/crossing, genotoxicity, cytotoxicity, oxidative stress, (pro‐)inflammatory potential and barrier integrity, for many of which no OECD TGs exist, have to be evaluated first. Consequently, NM risk assessments involve data from non‐guideline studies, requiring time‐consuming and challenging case‐by‐case evaluations. Establishing an OECD TG is a formal process aiming for international use according to the Mutual Acceptance of Data (MAD). However, not every promising NAM can be prioritised for OECD TGs. A qualification, based on an expert opinion, may enable an efficient use of adequate NAMs for a specific context‐of‐use. Furthermore, it supports the optimisation of promising NAMs for regulatory applications. Existing qualification systems operate in the context of e.g., drug development tools (FDA) and research and development into pharmaceuticals (EMA). The NAMS4NANO consortium was tasked to propose a generic framework for a qualification system for chemical risk assessment in the food and feed sector to speed up the regulatory use of NAMs. Here we describe our proposal including the process and evaluation criteria. A detailed test method description, preferably as standard operating procedures (SOPs), describing the set‐up of the NAM including its application and evaluation phase is crucial. Furthermore, the scientific validity, i.e. its reliability and relevance for the context‐of‐use, needs to be demonstrated, for which we suggest a less rigorous process compared to OECD TGs. We propose to initially establish a qualification system for NM risk assessment, aligned with the EFSA framework. This document is an interim version to stipulate a broader discussion among experts and stakeholders. [ABSTRACT FROM AUTHOR]

New Approach Methodologies (NAMs), broadly understood to include in silico, in chemico, in vitro and ex vivo methods, show great potential in advancing risk assessment albeit their regulatory implementation is lagging. The EFSA Guidance on risk assessment of nanomaterials (EFSA Guidance on Nano‐RA) suggests nano‐specific risk assessment is best achieved through Integrated Approaches to Testing and Assessment (IATAs) with NAMs as the first choice to generate new information. Integrating NAMs in risk assessment promises several advantages such as a better human focus, more detailed insights into molecular mechanisms and a higher efficacy. However, applying NAMs to NMs also poses considerable challenges such as issues related to dispersion stability, dosimetry, agglomeration, dissolution, transformations or assay interferences. Significant efforts are being undertaken by standardisation organisations and research projects to establish various NAMs for NMs. Here a thorough review is provided covering NAMs that will be potentially useful for risk assessment of NMs in the food and feed sector. It follows the structure of the EFSA Guidance on Nano‐RA and expands it, where needed, to support decision‐making in selection of NAMs for NM risk assessment. The review begins with an overview on nano‐specific NAM‐frameworks, followed by a description of individual NAMs including those relevant to NM physicochemical characterisation, exposure and hazard assessment covering toxicodynamics and toxicokinetics. The focus is on NAMs concerning NM degradation/dissolution, genotoxicity, cytotoxicity, oxidative stress, (pro‐)inflammation, and barrier integrity as those are important endpoints for initial screening according to the EFSA framework. As a result, in total 267 individual nano‐relevant NAMs, mostly "not validated" (with a few notable exceptions), were included in this review. Validation notwithstanding, NAMs could already prove relevant and reliable for risk assessment of NMs, especially in integrated approaches. [ABSTRACT FROM AUTHOR]

Metal sub-microparticles (SMPs) and nanoparticles (NPs) presence in food is attributable to increasing pollution from the environment in raw materials and finished products. In the present study, a multifaceted analytical strategy based on Environmental Scanning Electron Microscopy and High-Angle Annular Dark-Field—Scanning Transmission Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy (ESEM-EDX, HAADF-STEM-EDX) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was proposed for the detection and characterization of metal and metal-containing SMPs and NPs in durum wheat samples, covering a size measurement range from 1 nm to multiple µm. ESEM-EDX and ICP-MS techniques were applied for the assessment of SMP and NP contamination on the surface of wheat grains collected from seven geographical areas characterized by different natural and anthropic conditions, namely Italy, the USA, Australia, Slovakia, Mexico, Austria, and Russia. ICP-MS showed significant differences among the mean concentration levels of metals, with the USA and Italy having the highest level. ESEM-EDX analysis confirmed ICP-MS concentration measurements and measured the highest presence of particles < 0.8 µm in size in samples from Italy, followed by the USA. Less marked differences were observed when particles < 0.15 µm were considered. HAADF-STEM-EDX was applied to a selected number of samples for a preliminary assessment of internal contamination by metal SMPs and NPs, and to expand the measurable particle size range. The multifaceted approach provided similar results for Fe-containing SMPs and NPs. ICP-MS and ESEM-EDX also highlighted the presence of a significant abundance of Ti- and Al-containing particles, while for STEM-EDX, sample preparation artifacts complicated the interpretation. Finally, HAADF-STEM-EDX results provided relevant information about particles in the low nm range, since, by applying this technique, no particles smaller than 50 nm were observed in accordance with ESEM-EDX. [ABSTRACT FROM AUTHOR]

ObjectiveWe have previously shown that overexpression of the Na-Ca exchanger (NCX1), a protein responsible for Ca(2+) extrusion from cells, increases β-cell programmed cell death (apoptosis) and reduces β-cell proliferation. To further characterize the role of NCX1 in β-cells under in vivo conditions, we developed and characterized mice deficient for NCX1.Research design and methodsBiologic and morphologic methods (Ca(2+) imaging, Ca(2+) uptake, glucose metabolism, insulin release, and point counting morphometry) were used to assess β-cell function in vitro. Blood glucose and insulin levels were measured to assess glucose metabolism and insulin sensitivity in vivo. Islets were transplanted under the kidney capsule to assess their performance to revert diabetes in alloxan-diabetic mice.ResultsHeterozygous inactivation of Ncx1 in mice induced an increase in glucose-induced insulin release, with a major enhancement of its first and second phase. This was paralleled by an increase in β-cell proliferation and mass. The mutation also increased β-cell insulin content, proinsulin immunostaining, glucose-induced Ca(2+) uptake, and β-cell resistance to hypoxia. In addition, Ncx1(+/-) islets showed a two- to four-times higher rate of diabetes cure than Ncx1(+/+) islets when transplanted into diabetic animals.ConclusionsDownregulation of the Na/Ca exchanger leads to an increase in β-cell function, proliferation, mass, and resistance to physiologic stress, namely to various changes in β-cell function that are opposite to the major abnormalities seen in type 2 diabetes. This provides a unique model for the prevention and treatment of β-cell dysfunction in type 2 diabetes and after islet transplantation.