Nanoparticle-induced inflammation and fibrosis in ex vivo murine precision-cut liver slices and effects of nanoparticle exposure conditions

Efficacy of neutral electrolyzed water vs. common topical antiseptics in the healing of full‑thickness burn: Preclinical trial in a mouse model

Burn injuries impose challenges such as infection risk, pain management, fluid loss, electrolyte imbalance and psychological and emotional impact, on healthcare professionals, requiring effective treatments to enhance wound healing. The present study evaluated the efficacy superoxidized electrolyzed solution (SES), with low (SES-low) or high (SES-high) concentrations of active species, alone or in combination with a formulation in gel (G), in comparison with commonly prescribed treatments for burn injury, including nitrofurazone (NF) and silver sulfadiazine (S); normal saline was used as placebo (PI). A scald burn model was established in BALB/c mice. Measurements of the burned area and histological parameters such as inflammatory infiltration state, epithelial regeneration and collagen fibers were evaluated on days 3, 6, 9, 18 and 32 to assess healing score and status. All treatments achieved wound closure at day 32; histopathological parameters indicated that SES-low and SES-low + G performed better than the Pl and S groups (P<0.05). All treatments showed a lower count of inflammatory cells compared with S (P<0.05); for collagen deposition and orientation, SES-low + G showed a more uniform horizontal orientation compared with Pl, SES-high + G, NF and S groups (P<0.05). SES-Low was the most effective substance to induce favorable and organized healing, while S was the worst, inducing disorganized closure of the wound due to a pro-inflammatory effect.

Lost in Rotation: How TiO2 and ZnO Nanoparticles Disrupt Coordinated Epithelial Cell Rotation

Coordinated cell movement is a cardinal feature in tissue organization that highlights the importance of cells working together as a collective unit. Disruptions to this synchronization can have far-reaching pathological consequences, ranging from developmental disorders to tissue repair impairment. Herein, it is shown that metal oxide nanoparticles (NPs), even at low and non-toxic doses (1 and 10 µg mL-1), can perturb the coordinated epithelial cell rotation (CECR) in micropatterned human epithelial cell clusters via distinct nanoparticle-specific mechanisms. Zinc oxide (ZnO) NPs are found to induce significant levels of intracellular reactive oxygen species (ROS) to promote mitogenic activity. Generation of a new localized force field through changes in the cytoskeleton organization and an increase in cell density leads to the arrest of CECR. Conversely, epithelial cell clusters exposed to titanium dioxide (TiO2) NPs maintain their CECR directionality but display suppressed rotational speed in an autophagy-dependent manner. Thus, these findings reveal that nanoparticles can actively hijack the nano-adaptive responses of epithelial cells to disrupt the fundamental mechanics of cooperation and communication in a collective setting.

Bridging Smart Nanosystems with Clinically Relevant Models and Advanced Imaging for Precision Drug Delivery

Intracellular delivery of nano-drug-carriers (NDC) to specific cells, diseased regions, or solid tumors has entered the era of precision medicine that requires systematic knowledge of nano-biological interactions from multidisciplinary perspectives. To this end, this review first provides an overview of membrane-disruption methods such as electroporation, sonoporation, photoporation, microfluidic delivery, and microinjection with the merits of high-throughput and enhanced efficiency for in vitro NDC delivery. The impact of NDC characteristics including particle size, shape, charge, hydrophobicity, and elasticity on cellular uptake are elaborated and several types of NDC systems aiming for hierarchical targeting and delivery in vivo are reviewed. Emerging in vitro or ex vivo human/animal-derived pathophysiological models are further explored and highly recommended for use in NDC studies since they might mimic in vivo delivery features and fill the translational gaps from animals to humans. The exploration of modern microscopy techniques for precise nanoparticle (NP) tracking at the cellular, organ, and organismal levels informs the tailored development of NDCs for in vivo application and clinical translation. Overall, the review integrates the latest insights into smart nanosystem engineering, physiological models, imaging-based validation tools, all directed towards enhancing the precise and efficient intracellular delivery of NDCs.

Silica nanoparticles induce ferroptosis of HUVECs by triggering NCOA4-mediated ferritinophagy

Silica nanoparticles (SiNPs) have been widely used in electronics, chemistry, and biomedicine. Human exposure to SiNPs and possible health effects have attracted much attention. The potential cardiovascular toxicity of SiNPs and their related mechanisms are still unclear. Therefore, in this study, we investigated the toxic effects of SiNPs on human umbilical vein endothelial cells (HUVECs). We found that SiNPs could induce HUVECs ferroptosis. The results showed that the level of intracellular divalent iron and lipid peroxidation increased, and mitochondrial cristae decreased. In addition, the pretreatment of the iron chelator deferoxamine mesylate (DFO) could alleviate the ferroptosis of cells. Interestingly, pretreatment of 3-methyladenine (3-MA), an autophagy/PI3K inhibitor could partially inhibit autophagy and reduce ferroptosis, which indicated that autophagy played an important role in cell ferroptosis. Additionally, after knocking down nuclear receptor coactivator 4 (NCOA4), Ferritin Heavy Chain 1 (FTH1) expression was up-regulated, and the levels of divalent iron and lipid peroxidation decreased, which suggested that NCOA4 mediated the ferroptosis of HUVECs induced by SiNPs. In conclusion, this study shows that SiNPs can induce cardiovascular toxicity in which there is ferroptosis. NCOA4-mediated ferritinophagy and resultant ferroptosis by SiNPs may play an important role. This study provides a new theoretical strategy for the treatment and prevention of cardiovascular diseases in the future.

Culture of vibrating microtome tissue slices as a 3D model in biomedical research

The basic idea behind the use of 3-dimensional (3D) tools in biomedical research is the assumption that the structures under study will perform at the best in vitro if cultivated in an environment that is as similar as possible to their natural in vivo embedding. Tissue slicing fulfills this premise optimally: it is an accessible, unexpensive, imaging-friendly, and technically rather simple procedure which largely preserves the extracellular matrix and includes all or at least most supportive cell types in the correct tissue architecture with little cellular damage. Vibrating microtomes (vibratomes) can further improve the quality of the generated slices because of the lateral, saw-like movement of the blade, which significantly reduces tissue pulling or tearing compared to a straight cut. In spite of its obvious advantages, vibrating microtome slices are rather underrepresented in the current discussion on 3D tools, which is dominated by methods as organoids, organ-on-chip and bioprinting. Here, we review the development of vibrating microtome tissue slices, the major technical features underlying its application, as well as its current use and potential advances, such as a combination with novel microfluidic culture chambers. Once fully integrated into the 3D toolbox, tissue slices may significantly contribute to decrease the use of laboratory animals and is likely to have a strong impact on basic and translational research as well as drug screening.

Study of the Embryonic Toxicity of TiO2 and ZrO2 Nanoparticles

Currently, the widespread use of TiO₂ and ZrO₂ nanoparticles (NPs) in various industries poses a risk in terms of their potential toxicity. A number of experimental studies provide evidence of the toxic effect of TiO₂ and ZrO₂ NPs on biological objects. In order to supplement the level of knowledge and assess the risks of toxicity and danger of TiO₂ and ZrO₂ NPs, we decided to conduct a comprehensive experiment to study the embryonic toxicity of TiO₂ and ZrO₂ NPs in pregnant rats. For the experiment, mongrel white rats during pregnancy received aqueous dispersions of powders of TiO₂ and ZrO₂ NPs at a dose of 100 mg/kg/day. To characterize the effect of TiO₂ and ZrO₂ NPs on females and the postnatal ontogenesis of offspring, a complex of physiological and biochemical research methods was used. The results of the experiment showed that TiO₂ NPs as ZrO₂ NPs (100 mg/kg per os) cause few shifts of similar orientation in the maternal body. Neither TiO₂ NPs nor ZrO₂ NPs have an embryonic and teratogenic effect on the offspring in utero, but both modify its postnatal development.

Adverse effects and underlying mechanism of amorphous silica nanoparticles in liver

Amorphous silica nanoparticles (SiNPs) have been widely used and mass-producted due to its unique properties. With the life cycle of SiNPs-based products, SiNPs are further released into the air, soil, surface water and sediment, resulting in an increasing risk to humans. SiNPs could enter into the human body through vein, respiratory tract, digestive tract or skin. Moreover, recent evidences have showed that, regardless of exposure pathways, SiNPs could even be traced in liver, which is gradually considered as one of the main organs that SiNPs accumulate. Increasing evidences supported the link between SiNPs exposure and adverse liver effects. However, the research models are diverse and the molecular mechanisms have not been well integrated. In this review, the liver-related studies of SiNPs in vivo and in vitro were screened from the PubMed database by systematic retrieval method. We explored the interaction between SiNPs and the liver, and especially proposed a framework of SiNPs-caused liver toxicity, considering AOP Wiki and existing studies. We identified increased reactive oxygen species (ROS) as a molecular initiating event (MIE), oxidative stress, endoplasmic reticulum stress, lysosome disruption and mitochondrial dysfunction as subsequent key events (KEs), which gradually led to adverse outcomes (AOs) containing liver dysfunction and liver fibrosis through a series of key events about cell inflammation and death such as hepatocyte apoptosis/pyroptosis, hepatocyte autophagy dysfuncton and hepatic macrophages pyroptosis. To our best knowledge, this is the first AOP proposed on SiNPs-related liver toxicity. In the future, more epidemiological studies need to be performed and more biomarkers need to be explored to improve the AOP framework for SiNPs-associated liver toxicity.

Standardized Protocol for the Preparation of Precision-Cut Kidney Slices: A Translational Model of Renal Fibrosis

Renal fibrosis is a hallmark of progressive renal diseases. To date, there is a lack of effective therapeutics for the treatment of renal fibrosis, in part due to the scarcity of clinically relevant translational disease models. Since the early 1920s, hand-cut tissue slices have been used as a means to better understand organ (patho)physiology in a variety of scientific fields. From that time, the equipment and methodology for the preparation of tissue slices has continuously improved, thereby expanding the applicability of the model. Nowadays, precision-cut kidney slices (PCKS) have been demonstrated to be an extremely valuable translation model for renal (patho)physiology, bridging the gap between preclinical and clinical research. A key feature of PCKS is that the slices contain all cell types and acellular components of the whole organ in the original configuration while preserving cell-cell and cell-matrix interactions. In this chapter, we describe how to prepare PCKS and how the model can be implemented in fibrosis research.

NF-κB mediates silica-induced pulmonary inflammation by promoting the release of IL-1β in macrophages

Long-term exposure to respirable silica particles causes pulmonary inflammation and fibrosis primarily promoted by cytokines released from alveolar macrophages, yet the underlying mechanism is still unclear. From the perspective of nuclear factor kappa B (NF-κB), we studied the mechanism of IL-1β biosynthesis and release. Utilizing BAY 11-7082, an NF-κB specific inhibitor, we showed the alteration of macrophage viability and examined the expression of both IL-1β and NF-κB in vitro. We found that silica nanoparticles (SiNPs) were internalized by macrophages and caused damage to cell integrity. The immunofluorescence assay showed that SiNPs exposure enhanced the expression of IL-1β and NF-κB, which could be effectively suppressed by BAY 11-7082. Besides, we built silica exposure mouse model by intratracheally instilling 5 mg of SiNPs and checked the effect of silica exposure on pulmonary pathological changes. Consistently, we found an upregulation of IL-1β and NF-κB after SiNPs exposure, along with the aggravated inflammatory cell infiltration, thickened alveolar wall, and enhanced expression of collagens. In conclusion, SiNPs exposure causes pulmonary inflammation and fibrosis that is regulated by NK-κB through upregulating IL-1β in alveolar macrophages.

Green Silver Nanoparticles Promote Inflammation Shutdown in Human Leukemic Monocytes

The use of silver nanoparticles (Ag NPs) in the biomedical field deserves a mindful analysis of the possible inflammatory response which could limit their use in the clinic. Despite the anti-cancer properties of Ag NPs having been widely demonstrated, there are still few studies concerning their involvement in the activation of specific inflammatory pathways. The inflammatory outcome depends on the synthetic route used in the NPs production, in which toxic reagents are employed. In this work, we compared two types of Ag NPs, obtained by two different chemical routes: conventional synthesis using sodium citrate and a green protocol based on leaf extracts as a source of reduction and capping agents. A careful physicochemical characterization was carried out showing spherical and stable Ag NPs with an average size between 20 nm and 35 nm for conventional and green Ag NPs respectively. Then, we evaluated their ability to induce the activation of inflammation in Human Leukemic Monocytes (THP-1) differentiated into M0 macrophages using 1 µM and 2 µM NPs concentrations (corresponded to 0.1 µg/mL and 0.2 µg/mL respectively) and two-time points (24 h and 48 h). Our results showed a clear difference in Nuclear Factor κB (NF-κb) activation, Interleukins 6–8 (IL-6, IL-8) secretion, Tumor Necrosis Factor-α (TNF-α) and Cyclooxygenase-2 (COX-2) expression exerted by the two kinds of Ag NPs. Green Ag NPs were definitely tolerated by macrophages compared to conventional Ag NPs which induced the activation of all the factors mentioned above. Subsequently, the exposure of breast cancer cell line (MCF-7) to the green Ag NPs showed that they exhibited antitumor activity like the conventional ones, but surprisingly, using the MCF-10A line (not tumoral breast cells) the green Ag NPs did not cause a significant decrease in cell viability.

Best Practices and Progress in Precision-Cut Liver Slice Cultures

Thirty-five years ago, precision-cut liver slices (PCLS) were described as a promising tool and were expected to become the standard in vitro model to study liver disease as they tick off all characteristics of a good in vitro model. In contrast to most in vitro models, PCLS retain the complex 3D liver structures found in vivo, including cell–cell and cell–matrix interactions, and therefore should constitute the most reliable tool to model and to investigate pathways underlying chronic liver disease in vitro. Nevertheless, the biggest disadvantage of the model is the initiation of a procedure-induced fibrotic response. In this review, we describe the parameters and potential of PCLS cultures and discuss whether the initially described limitations and pitfalls have been overcome. We summarize the latest advances in PCLS research and critically evaluate PCLS use and progress since its invention in 1985.

Multiscale Synchrotron-Based Imaging Analysis for the Transfer of PEGylated Gold Nanoparticles In Vivo

High spatial resolution imaging analysis is urgently needed to explore the biodistribution, transfer and clearance profiles, and biological impact of nanoparticles in the body, which will be helpful to clarify the efficacy of nanomedicine in clinical applications. Herein, by combination with multiscale synchrotron-based imaging techniques, including X-ray fluorescence (XRF) spectrometry, Fourier transform infrared (FTIR) spectroscopy, and micro X-ray phase contrast computed tomography (micro-XPCT), we visually displayed the transfer patterns and site-specific distribution of PEGylated gold nanoparticles (PEG-GNPs) in the suborgans of the liver, spleen, and kidney after an intravenous injection in mice. A combination of XRF and FTIR imaging analysis showed that the PEG bands presented similar distribution patterns with Au in the intraorgans, suggesting the stability of PEGylation on GNPs. We show that the PEG-GNPs presented heterogeneous distribution in the hepatic lobules with a large amount around the portal vein zone and then a gradient decrease in the sinusoidal region and the CV zone; in the spleen, it gradually accumulated in the splenic red pulp over time; and in the kidney, it quickly transported via the bloodstream to the renal pyramids and renal pelvis, and parts of PEG-GNPs finally accumulated in the renal medulla and renal cortex. Multidimensional micro-XPCT images further show that the PEG-GNP transfer in the liver induced hepatic blood vessel dilatation while they transferred in the liver, providing evidence of GNP transport across the blood vessel endothelial barrier.