NAM journal最新文献

New approach methodologies (NAMs) are changing the ways by which alternative toxicology, in vitro mainly, is approaching the evaluation of hazard of novel materials or compounds. Engineered nanoparticles (NPs) are a typical class of compounds where NAMs found an important area of application. The number of novel NPs and NPs-based products are increasing at a pace that classical in vivo toxicology has difficult to keep. NAMs on the other hand are faster and may provide more human relevant outcomes. According to the Safe and Sustainable by design (SSbD) framework, we report here the comparison of silver NPs (AgNPs) with different functionalization (naked, with curcumin or with hydroxyethyl cellulose). A lung in vitro model (A549 cells with THP-1-derived macrophages) is exposed with a NAM at the air-liquid interface (ALI). The outcomes are explored with a genomic approach followed by RT-PCR. The results show the relevance of combining two de facto NAM to obtain data relevant to human expected exposure and to mine the plethora of hazard information in vitro model can provide. The combination of these approaches should be considered as a reference approach also to pave the road for regulatory acceptance.

Blood-brain barrier (BBB) permeation determines human brain exposure to chemicals and is therefore a prerequisite for neurotoxicity. However, the lack of toxicokinetic BBB models remains a critical uncertainty in regulatory in vitro risk assessment, which was highlighted in the new EU roadmap towards phasing out animal testing. Human induced pluripotent stem cell (hiPSC)-derived BBB models combined with clinical positron emission tomography (PET) data provide translational benchmarks for evaluating whether in vitro permeability data predict human brain exposure. Microphysiological systems (MPS) may better emulate physiological flow than static transwell® systems. Nonetheless, it remains unclear whether additional complexity introduced by flow improves fitness-for-purpose, reproducibility, and regulatory utility of BBB new approach methodologies (NAMs). Therefore, we directly compared our static hiPSC-derived BBB model, which was previously validated with human clinical PET brain-penetration data, with its microfluidic counterpart to determine whether flow translates into measurable added value for human brain exposure assessment. The comparative pilot study demonstrated that microfluidic implementation of the static model was technically feasible and maintained key BBB functionality in terms of barrier integrity, efflux capacity, and permeability. However, the MPS displayed reduced in vivo-like barrier characteristics and lower brain-penetration predictive performance than the static counterpart within the tested compound set, which is relevant for regulatory neurotoxicity assessment. In addition, the static model offered advantages in standardization, robustness, and throughput that are important for future regulatory implementation. Finally, this study identified technical limitations of the selected microfluidic transwell®-in-chip implementation that may guide the future development of standardized, commercially available BBB systems.

In Next Generation Risk Assessments (NGRAs) of cosmetic ingredients, evaluations of systemic exposure after topical application range from conservative screening estimates to higher tier kinetic models. The latter need robust and predictive in silico and in vitro skin absorption and metabolism models to ensure regulatory confidence. This review provides an update on skin xenobiotic metabolizing enzymes (XMEs) and in vitro skin metabolism models of varying complexities. It is intended primarily for safety assessors and study planners who need to select and interpret skin-metabolism NGRA approaches for cosmetic ingredients. Qualitative information helps to inform subsequent tiers of the NGRA workflow by identifying potential reactive intermediates, while structural and SAR information helps assess bioactivation and detoxification pathways. Quantitative data should be of good quality, correctly interpreted and extrapolated to in vivo using appropriate equations and scaling factors to provide a relevant indication of first-pass skin metabolism. This can be influenced by access to XMEs, extrinsic and intrinsic factors. Challenges and open questions remain regarding standardized metabolism assays and related guidelines, as well as the development of in silico models to predict skin metabolites and skin bioavailability for integration into Physiologically Based Kinetic (PBK) models. Despite advances in technologies, efforts are still needed to improve our understanding of skin XMEs and their location, and to develop suitable models to predict and measure metabolic pathways. There are increasing efforts to integrate skin metabolism data into PBK models for dermal exposure. Further research into skin metabolism is needed for NGRAs of topically applied cosmetic ingredients.

Polymers are substances composed of molecules containing repeating monomer units and exhibiting a distribution of molecular weights due to differences in chain length. This inherent heterogeneity distinguishes them from discrete molecules and may complicate the application and interpretation of standardized hazard assessment procedures. Polymers have been exempt from REACH registration since its inception. While a formal revision of the REACH Regulation is currently no longer anticipated, discussions on introducing additional information requirements for certain polymers remain ongoing through implementing measures and comitology processes. These may include analytical, ecotoxicological, and toxicological data. Standardized regulatory testing typically relies on OECD test guidelines (TGs), which were primarily developed for well-defined chemical substances. Their applicability to polymers, with their molecular weight distribution, heterogenous composition and often challenging physiochemical properties, remains uncertain. The present study evaluates the technical applicability of four guidelines (OECD TG 120 (solution/extraction behavior of polymers in water), OECD TG 202 (Daphnia sp. acute immobilization), OECD TG 439 (in vitro skin irritation using reconstructed human epidermis), and OECD TG 487 (in vitro mammalian cell micronucleus test)) to 17 polymer materials. Testing was conducted in water, cell-culture media, and at the air-liquid interface. Results show that TG 120's sample preparation methods were not universally applicable. TG 202 is generally suitable for water-soluble polymers, however, reactive and poorly soluble polymers present challenges. TG 487 is only applicable to water-soluble polymers, and TG 439 is technically broadly applicable if the test material is pipettable or spoon-applicable. Our findings highlight the limitations of current OECD TGs for polymers and emphasize the need for adapted, standardized methods. This work cautions against indiscriminate use of existing TGs tailored for small molecules and supports the development of polymer-specific testing strategies to ensure reliable and accurate regulatory evaluation.

In Next Generation Risk Assessments, measurements of hepatic intrinsic clearance (CL_int , _{in vitro} ) and metabolite(s) formation can markedly impact in vitro to in vivo extrapolations and subsequent testing of parent and/or metabolites in in vitro bioassays. It is especially important for slowly metabolized chemicals to use the most suitable model and experimental design to ensure that the IVIVE is accurate. We evaluated four long-term hepatic models (sandwich cultures of primary human hepatocytes (PHH), HepatoPac, HµREL and TruVivo), as well as PHH suspensions, using salicylic acid, 1-methyl-2-pyrrolidinone (NMP) and valproic acid. Assay designs differed in terms of positive and negative controls, cell densities and incubation durations. All models generated a measurable CL_int , _{in vitro} value for salicylic acid i.e. depletion >20%. Differences may be due to donor differences and the cell number. HepatoPac generally resulted in higher values compared with the other models. NMP was not metabolized by HµREL and TruVivo models and a reliable value was only possible using HepatoPac. NMP was metabolized by sandwich cultures; however, the half-life was much longer than the incubation duration. To derive a more robust value, follow up testing could include longer incubation times. Valproic acid was only metabolized in one of the three models in which it was detected, namely sandwich cultures. In conclusion, PHH sandwich cultures, HepatoPac, HµREL and TruVivo models are superior to PHH suspensions with respect to maintaining XME activities over days and for measuring CL_{int, in vitro} values for slowly metabolized chemicals. To gain regulatory acceptance and better interpret data from different labs, we recommend increasing the number of chemicals tested and harmonization of protocols.

Neurodegenerative diseases are characterized by progressive neuronal loss driven not only by intrinsic cellular dysfunction but also by complex interactions within the neural microenvironment, including extracellular matrix (ECM) composition, neuroimmune signaling, and neurovascular dynamics. Conventional two-dimensional systems and animal models fail to recapitulate this complexity, limiting their predictive value. Recent advances in three-dimensional (3D) neural platforms, particularly 3D bioprinting and organoid technologies, have enabled the development of more physiologically relevant models that better reproduce brain architecture and multicellular organization. These systems enable the investigation of key pathological processes, including neuroinflammation, protein aggregation, and synaptic dysfunction, while aligning with emerging New Approach Methodologies (NAMs) aimed at improving human-relevant disease modeling. However, current platforms remain constrained by limited maturation, insufficient vascularization, incomplete immune integration, and experimental variability. A central premise of this review is that effective disease modeling requires not only biological complexity but also precise engineering of the neural microenvironment. To organize this engineering effort, we introduce the Neural Microenvironment Design Code (NMDC), a framework encompassing mechanical, biochemical, electrophysiological, and immune-barrier design codes that collectively define the neural microenvironment. Using the NMDC as an organizing framework, we synthesize recent advances across major neurodegenerative diseases and identify key design principles governing biomaterial selection, spatial organization, cellular integration, and biofabrication. Collectively, these approaches position 3D neural models as programmable, human-relevant systems for predictive drug screening and personalized therapeutic development.

Reliable assessment of skin sensitization hazard and potency remains challenging for fragrance and other substances. Although current in chemico and in vitro assays perform well within their respective applicability domains, challenges remain for highly lipophilic, poorly water-soluble, cytotoxic chemicals and substances requiring metabolic or abiotic activation. To address these challenges, the established 2D Cocultured Activation Test (COCAT), combining HaCaT keratinocytes with THP-1 cells as surrogate dendritic cells, was modified by incorporating a reconstructed human epidermis (RHE). The resulting 3D RHE/THP-1 coculture model was evaluated using chemicals that presented challenges for quantitative assessment in the 2D COCAT method. Results were compared with previously published 2D COCAT data and human and animal weight-of-evidence (WoE)-derived skin sensitization potency values (PVs). Incorporation of the RHE substantially expanded the applicability domain by enabling quantitative potency assessment of substances for which robust concentration-response relationships could not previously be established. The 3D RHE/THP-1 model differentiated all sixteen substances over more than three orders of magnitude in skin sensitization potency and enabled systematic comparison of structurally related substances. Alcohol-aldehyde potency relationships were highly structure dependent, ranging from minor differences between benzyl alcohol and benzaldehyde to approximately 15-fold differences between hydroxycitronellol and hydroxycitronellal. Potency estimates showed good overall agreement with published PVs. These findings demonstrate that incorporation of RHE extends the applicability domain of the COCAT method, provides a more physiologically relevant in vitro approach for quantitative skin sensitization potency assessment, and supports the further development of human-relevant, animal-free next-generation risk assessment strategies.