Narrow Results

Nanotechnology represents major scientific and economic issues for the future. TiO₂ is used as a reference nanoparticle (NP) for research and workplace exposure assessments due to its important industrial production. However, to date little consistent information exists about its human health effects. Approximately 50% of all TiO₂in vivo studies targeting the respiratory tract have been by inhalation and these exposures are often in the form of agglomerates rather than as individual NPs. Therefore, the size of the NP agglomerates represents the effective size interacting with the biological material and could thereby influence the NP mechanisms of action. Thus, interpretation of nanotoxicological data without considering the agglomeration state could partly explain the heterogeneous results found in the scientific literature for TiO₂ NPs. The objective of this review is to examine the literature concerning the importance of TiO₂ aerosol characterization in the assessment of pulmonary toxicity in rodents. In this way, this review reveals that the pulmonary responses following inhalation of TiO₂ NPs might not depend solely on the primary NP size, but also on the crystal phase, the NP agglomerate size, its structure and the mass concentration. It also shows that TiO₂ NPs may exert their toxicity mechanisms specifically because of the size of their agglomerates in aerosols, thus supporting the concept that aerosols composed essentially of small (< 100 nm) or large (> 100 nm) NP agglomerates do not seem to follow the same pulmonary toxicity mechanisms.

The ubiquitous presence of micro and nanoplastics (MNPs) in the environment has become a pressing global concern, particularly regarding the potential impacts on human health. This review underscores the urgent need for an integrative research framework that bridges the gap between epidemiological observations and toxicological insights. Human exposure to MNPs occurs predominantly through ingestion, inhalation and dermal contact pathways. Epidemiological findings have consistently demonstrated the presence of MNPs in diverse human tissues, signaling a broad exposure and emphasizing the imperative to explore potential health risks. Population surveys have shown that the concentration of MNPs in the feces of people using disposable plastic tableware reaches 24.65 items/g. These results are associated with changes in microbiota composition and metabolite levels relevant to central nervous system disorders, energy metabolism and inflammatory responses. The detectable abundance of MNPs in the nasal mucus of individuals wearing N95 masks was measured to be 10.6 ± 2.3 items/mg. Moreover, population- based studies have linked MNP exposure to adverse health outcomes, suggesting correlation relationships between exposure levels and specific diseases such as inflammatory bowel disease (IBD) and human pulmonary ground-glass nodules (GGN). These associations underscore the necessity for in-depth toxicological investigations to elucidate the toxicity mechanisms of MNPs. Meanwhile, laboratory-based toxicological studies have the potential to reveal causative relationships and various in vitro and in vivo models have been used to explore the mechanisms of the toxicity of MNPs in the gastrointestinal tract, lungs and cardiovascular system. However, early studies failed to reflect on the complexity of the real environment. To foster interdisciplinary collaborations, this paper aims to reconcile the disparities between exposure risks and human health impacts. By critically reviewing recent advancements in understanding the exposure risks of MNPs, epidemiological observations and organ-specific toxicity, this work furnishes a comprehensive perspective on the health implications of MNPs.

The ubiquitous presence of micro and nanoplastics (MNPs) in the environment has become a pressing global concern, particularly regarding the potential impacts on human health. This review underscores the urgent need for an integrative research framework that bridges the gap between epidemiological observations and toxicological insights. Human exposure to MNPs occurs predominantly through ingestion, inhalation and dermal contact pathways. Epidemiological findings have consistently demonstrated the presence of MNPs in diverse human tissues, signaling a broad exposure and emphasizing the imperative to explore potential health risks. Population surveys have shown that the concentration of MNPs in the feces of people using disposable plastic tableware reaches 24.65 items/g. These results are associated with changes in microbiota composition and metabolite levels relevant to central nervous system disorders, energy metabolism and inflammatory responses. The detectable abundance of MNPs in the nasal mucus of individuals wearing N95 masks was measured to be 10:6 ± 2:3 items/mg. Moreover, population-based studies have linked MNP exposure to adverse health outcomes, suggesting correlation relationships between exposure levels and specific diseases such as inflammatory bowel disease (IBD) and human pulmonary ground-glass nodules (GGN). These associations underscore the necessity for in-depth toxicological investigations to elucidate the toxicity mechanisms of MNPs. Meanwhile, laboratory-based toxicological studies have the potential to reveal causative relationships and various in vitro and in vivo models have been used to explore the mechanisms of the toxicity of MNPs in the gastrointestinal tract, lungs and cardiovascular system. However, early studies failed to reflect on the complexity of the real environment. To foster interdisciplinary collaborations, this paper aims to reconcile the disparities between exposure risks and human health impacts. By critically reviewing recent advancements in understanding the exposure risks of MNPs, epidemiological observations and organ-specific toxicity, this work furnishes a comprehensive perspective on the health implications of MNPs.