Biodistribution and pulmonary metabolic effects of silver nanoparticles in mice following acute intratracheal instillations

Comprehensive pulmonary metabolic responses to silica nanoparticles exposure in Fisher 344 rats

Silica nanoparticles (SiNPs) could induce adverse pulmonary effects, but the mechanism was not clear enough. Metabolomics is a sensitive and high-throughput approach that could investigate the intrinsic causes of adverse health effects caused by SiNPs. The current investigation represented the first in vivo metabolomics study examining the chronic pulmonary toxicity of SiNPs at a low dosage, mimicking real human exposure situation. The recovery process after the cessation of exposure was also taken into consideration. Fisher 344 rats were treated with either saline or SiNPs for 6 months. Half of the animals in each group received an additional six-month period for recovery. The findings indicated that chronic low-level exposure to SiNPs resulted in notable alterations in pulmonary metabolism of amino acids, lipids, carbohydrates, and nucleotides. SiNPs exerted an impact on various metabolites and metabolic pathways which are linked to oxidative stress, inflammation and tumorigenesis. These included but were not limited to L-carnitine, spermidine, taurine, xanthine, and glutathione metabolism. The metabolic alterations caused by SiNPs exhibited a degree of reversibility. However, the interference of SiNPs on two metabolic pathways related to tumorigenesis was observed to persist after a recovery period. The two metabolic pathways are glycerophospholipid metabolism as well as phenylalanine, tyrosine and tryptophan biosynthesis. This study elucidated the metabolic alterations induced by chronic low-level exposure to SiNPs and presented novel evidence of the chronic pulmonary toxicity and carcinogenicity of SiNPs, from a metabolomic perspective.

Metabolomics-directed nanotechnology in viral diseases management: COVID-19 a case study

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently regarded as the twenty-first century's plague accounting for coronavirus disease 2019 (COVID-19). Besides its reported symptoms affecting the respiratory tract, it was found to alter several metabolic pathways inside the body. Nanoparticles proved to combat viral infections including COVID-19 to demonstrate great success in developing vaccines based on mRNA technology. However, various types of nanoparticles can affect the host metabolome. Considering the increasing proportion of nano-based vaccines, this review compiles and analyses how COVID-19 and nanoparticles affect lipids, amino acids, and carbohydrates metabolism. A search was conducted on PubMed, ScienceDirect, Web of Science for available information on the interrelationship between metabolomics and immunity in the context of SARS-CoV-2 infection and the effect of nanoparticles on metabolite levels. It was clear that SARS-CoV-2 disrupted several pathways to ensure a sufficient supply of its building blocks to facilitate its replication. Such information can help in developing treatment strategies against viral infections and COVID-19 based on interventions that overcome these metabolic changes. Furthermore, it showed that even drug-free nanoparticles can exert an influence on biological systems as evidenced by metabolomics.

Silver nanoparticles induced hepatoxicity via the apoptotic/antiapoptotic pathway with activation of TGFβ-1 and α-SMA triggered liver fibrosis in Sprague Dawley rats

Despite the extraordinary use of silver nanoparticles (AgNPs) in medicinal purposes and the food industry, there is rising worry about potential hazards to human health and the environment. The existing study aims to assess the hepatotoxic effects of different dosages of AgNPs by evaluating hematobiochemical parameters, oxidative stress, liver morphological alterations, immunohistochemical staining, and gene expression to clarify the mechanism of AgNPs' hepatic toxic potential. Forty male Sprague Dawley rats were randomly assigned into control and three AgNPs intraperitoneally treated groups 0.25, 0.5, and 1 mg/kg b.w. daily for 15 and 30 days. AgNP exposure reduced body weight, caused haematological abnormalities, and enhanced hepatic oxidative and nitrosative stress with depletion of the hepatic GSH level. Serum hepatic injury biomarkers with pathological hepatic lesions where cholangiopathy emerges as the main hepatic alteration in a dosage- and duration-dependent manner were also elevated. Furthermore, immunohistochemical labelling of apoptotic markers demonstrated that Bcl-2 was significantly downregulated while caspase-3 was significantly upregulated. In conclusion, the hepatotoxic impact of AgNPs may be regulated by two mechanisms, implying the apoptotic/antiapoptotic pathway via raising BAX and inhibiting Bcl-2 expression levels in a dose-dependent manner. The TGF-β1 and α-SMA pathway which triggered fibrosis with incorporation of iNOS which consequently activates the inflammatory process were also elevated. To our knowledge, there has been no prior report on the experimental administration of AgNPs in three different dosages for short and long durations in rats with the assessment of Bcl-2, BAX, iNOS, TGF-β1, and α-SMA gene expressions.

The Fate of Intranasally Instilled Silver Nanoarchitectures

The intranasal administration of drugs allows an effective and noninvasive therapeutic action on the respiratory tract. In an era of rapidly increasing antimicrobial resistance, new approaches to the treatment of communicable diseases, especially lung infections, are urgently needed. Metal nanoparticles are recognized as a potential last-line defense, but limited data on the biosafety and nano/biointeractions preclude their use. Here, we quantitatively and qualitatively assess the fate and the potential risks associated with the exposure to a silver nanomaterial model (i.e., silver ultrasmall-in-nano architectures, AgNAs) after a single dose instillation. Our results highlight that the biodistribution profile and the nano/biointeractions are critically influenced by both the design of the nanomaterial and the chemical nature of the metal. Overall, our data suggest that the instillation of rationally engineered nanomaterials might be exploited to develop future treatments for (non)communicable diseases of the respiratory tract.

Indirect mediators of systemic health outcomes following nanoparticle inhalation exposure

The growing field of nanoscience has shed light on the wide diversity of natural and anthropogenic sources of nano-scale particulates, raising concern as to their impacts on human health. Inhalation is the most robust route of entry, with nanoparticles (NPs) evading mucociliary clearance and depositing deep into the alveolar region. Yet, impacts from inhaled NPs are evident far outside the lung, particularly on the cardiovascular system and highly vascularized organs like the brain. Peripheral effects are partly explained by the translocation of some NPs from the lung into the circulation; however, other NPs largely confined to the lung are still accompanied by systemic outcomes. Omic research has only just begun to inform on the complex myriad of molecules released from the lung to the blood as byproducts of pulmonary pathology. These indirect mediators are diverse in their molecular make-up and activity in the periphery. The present review examines systemic outcomes attributed to pulmonary NP exposure and what is known about indirect pathological mediators released from the lung into the circulation. Further focus was directed to outcomes in the brain, a highly vascularized region susceptible to acute and longer-term outcomes. Findings here support the need for big-data toxicological studies to understand what drives these health outcomes and better predict, circumvent, and treat the potential health impacts arising from NP exposure scenarios.

Analysis of Nanomaterials on Biological and Environmental Systems and New Analytical Methods for Improved Detection

The advancing field of nanoscience has produced lower mass, smaller size, and expanded chemical composition nanoparticles over recent years. These new nanoparticles have challenged traditional analytical methods of qualification and quantification. Such advancements in nanoparticles and nanomaterials have captured the attention of toxicologists with concerns regarding the environment and human health impacts. Given that nanoparticles are only limited by size (1–100 nm), their chemical and physical characteristics can drastically change and thus alter their overall nanotoxicity in unpredictable ways. A significant limitation to the development of nanomaterials is that traditional regulatory and scientific methods used to assess the biological and environmental toxicity of chemicals do not generally apply to the assessment of nanomaterials. Significant research effort has been initiated, but much more is still needed to develop new and improved analytical measurement methods for detecting and quantitating nanomaterials in biological and environmental systems.

Impact of Particle Size on Toxicity, Tissue Distribution and Excretion Kinetics of Subchronic Intratracheal Instilled Silver Nanoparticles in Mice

The unique physicochemical properties of silver nanoparticles (AgNPs) make them useful in a wide range of sectors, increasing their propensity for human exposure, as well as the need for thorough toxicological assessment. The biodistribution of silver, hematological parameters and GSH/GSSG levels in the lung and liver were studied in mice that were intratracheally instilled with AgNP (5 and 50 nm) and AgNO₃ once a week for 5 weeks, followed by a recovery period of up to 28 days (dpi). Data was gathered to build a PBPK model after the entry of AgNPs into the lungs. AgNPs could be absorbed into the blood and might cross the physiological barriers and be distributed extensively in mice. Similar to AgNO₃, AgNP5 induced longer-lasting toxicity toward blood cells and increased GSH levels in the lung. The exposure to AgNP50 increased the GSH from 1 dpi onward in the liver and silver was distributed to the organs after exposure, but its concentration decreased over time. In AgNP5 treated mice, silver levels were highest in the spleen, kidney, liver and blood, persisting for at least 28 days, suggesting accumulation. The major route for excretion seemed to be through the urine, despite a high concentration of AgNP5 also being found in feces. The modeled silver concentration was in line with the in vivo data for the heart and liver.

In Vitro Hepatotoxic and Neurotoxic Effects of Titanium and Cerium Dioxide Nanoparticles, Arsenic and Mercury Co-Exposure

Considering the increasing emergence of new contaminants, such as nanomaterials, mixing with legacy contaminants, including metal(loid)s, it becomes imperative to understand the toxic profile resulting from these interactions. This work aimed at assessing and comparing the individual and combined hepatotoxic and neurotoxic potential of titanium dioxide nanoparticles (TiO₂NPs 0.75–75 mg/L), cerium oxide nanoparticles (CeO₂NPs 0.075–10 μg/L), arsenic (As 0.01–2.5 mg/L), and mercury (Hg 0.5–100 mg/L) on human hepatoma (HepG2) and neuroblastoma (SH-SY5Y) cells. Viability was assessed through WST-1 (24 h) and clonogenic (7 days) assays and it was affected in a dose-, time- and cell-dependent manner. Higher concentrations caused greater toxicity, while prolonged exposure caused inhibition of cell proliferation, even at low concentrations, for both cell lines. Cell cycle progression, explored by flow cytometry 24 h post-exposure, revealed that TiO₂NPs, As and Hg but not CeO₂NPs, changed the profiles of SH-SY5Y and HepG2 cells in a dose-dependent manner, and that the cell cycle was, overall, more affected by exposure to mixtures. Exposure to binary mixtures revealed either potentiation or antagonistic effects depending on the composition, cell type and time of exposure. These findings prove that joint toxicity of contaminants cannot be disregarded and must be further explored.

Integrative Metabolomics, Proteomics and Transcriptomics Analysis Reveals Liver Toxicity of Mesoporous Silica Nanoparticles

As pharmaceutical excipients, mesoporous silica nanoparticles (MSNs) have attracted considerable concern based on potential risks to the public. The impact of MSNs on biochemical metabolism is poorly understood, and few studies have compared the effects of MSNs administered via different routes. To evaluate the hepatotoxicity of MSNs, metabolomics, proteomics and transcriptomic analyses were performed in mice after intravenous (20 mg/kg/d) or oral ad-ministration (200 mg/kg/d) of MSNs for 10 days. Intravenous injection induced significant hepatic injury based on pathological inspection and increased the levels of AST/ALT and the inflammatory factors IL-6, IL-1β and TNF-a. Omics data suggested intravenous administration of MSNs perturbed the following metabolites: succinate, hypoxanthine, GSSG, NADP+, NADPH and 6-phosphogluconic acid. In addition, increases in GPX, SOD3, G6PD, HK, and PFK at proteomic and transcriptomic levels suggested elevation of glycolysis and pentose phosphate pathway, synthesis of glutathione and nucleotides, and antioxidative pathway activity, whereas oxidative phosphorylation, TCA and mitochondrial energy metabolism were reduced. On the other hand, oral administration of MSNs disturbed inflammatory factors and metabolites of ribose-5-phosphate, 6-phosphogluconate, GSSG, and NADP+ associated with the pentose phosphate pathway, glutathione synthesis and oxidative stress albeit to a lesser extent than intravenous injection despite the administration of a ten-fold greater dose. Overall, systematic biological data suggested that intravenous injection of nanoparticles of pharmaceutical excipients substantially affected hepatic metabolism function and induced oxidative stress and inflammation, whereas oral administration exhibited milder effects compared with intravenous injection.

Bioavailability and toxicity of silver nanoparticles: Determination based on toxicokinetic-toxicodynamic processes

Determining the bioavailability and toxicity mechanism of silver nanoparticles (AgNPs) is challenging as Ag⁺ is continuously released by external or internal AgNP dissolution in the actual exposure system (regardless of the laboratory or the natural environment). Here a novel pulsed-gradient Ag⁺ (AgNO₃) exposure was conducted with zebrafish (Danio rerio) larvae to simulate dissolved gradient concentrations of Ag⁺ from polyvinylpyrrolidone (PVP)-coated AgNPs. The accumulation and toxicity of the pulsed-gradient Ag⁺ (AgNO₃) and, in the meantime, the released Ag⁺ from PVP-AgNPs were predicted using a toxicokinetic-toxicodynamic (TK-TD) model with obtained Ag⁺ parameters. In order to further understand the possible mechanism of PVP-AgNP releasing Ag⁺ in the body, subcellular fractions (S9) of zebrafish were also used to incubate with AgNPs in vitro to mimic the realistic in vivo scenarios. In the TK process, in vivo analysis showed that AgNPs released around twice as many Ag⁺ into the body than were detected with a single Ag⁺ pulse-exposure system; this was supported by evidence that subcellular S9 fractions might cause the PVP-AgNPs to lose the capping agent and favor Ag⁺ release. In the TD process, toxicity (survival rate) was predicted by the total bodily Ag(I) concentration, suggesting that AgNP toxicity in larvae was mainly due to gradually released Ag⁺ rather than AgNPs themselves. This study helps clarify the role of Ag⁺ in AgNP toxicity and offers a novel framework by which to investigate the toxicity of metal nanoparticles and corresponding metal ions in biological systems.

Progress in the Application of Nano- and Micro-based Drug Delivery Systems in Pulmonary Drug Delivery

Nanotechnology is associated with the development of particles in the nano-size range that can be used in a wide range of applications in the medical field. It has gained more importance in the pharmaceutical research field particularly in drug delivery, as it results in enhanced therapeutic drug performance, improved drug solubility, targeted drug delivery to the specific sites, minimized side effects, and prolonged drug retention time in the targeted site. To date, the application of nanotechnology continues to offer several benefits in the treatment of various chronic diseases and results in remarkable improvements in treatment outcomes. The use of nano-based delivery systems such as liposomes, micelles, and nanoparticles in pulmonary drug delivery have shown to be a promising strategy in achieving drug deposition and maintained controlled drug release in the lungs. They have been widely used to minimize the risks of drug toxicity in vivo. In this review, recent advances in the application of nano- and micro-based delivery systems in pulmonary drug delivery for the treatment of various pulmonary diseases, such as lung cancer, asthma, and chronic obstructive pulmonary disease, are highlighted. Limitations in the application of these drug delivery systems and some key strategies in improving their formulation properties to overcome challenges encountered in drug delivery are also discussed.