Preclinical safety and hepatotoxicity evaluation of biomineralized copper sulfide nanoagents.

Albumin-biomineralized copper sulfide nanoparticles (Cu2-xS NPs) have attracted much attention as an emerging phototheranostic agent due to their advantages of facile preparation method and high biocompatibility. However, comprehensive preclinical safety evaluation is the only way to meet its further clinical translation. We herein evaluate detailedly the safety and hepatotoxicity of bovine serum albumin-biomineralized Cu2-xS (BSA@Cu2-xS) NPs with two different sizes in rats. Large-sized (LNPs, 17.8 nm) and small-sized (SNPs, 2.8 nm) BSA@Cu2-xS NPs with great near-infrared absorption and photothermal conversion efficiency are firstly obtained. Seven days after a single-dose intravenous administration, SNPs distributed throughout the body are cleared primarily through the feces, while a large amount of LNPs remained in the liver. A 14-day subacute toxicity study with a 28-day recovery period are conducted, showing long-term hepatotoxicity without recovery for LNPs but reversible toxicity for SNPs. Cellular uptake studies indicate that LNPs prefer to reside in Kupffer cells, leading to prolonged and delayed hepatotoxicity even after the cessation of NPs administration, while SNPs have much less Kupffer cell uptake. RNA-sequencing analysis for gene expression indicates that the inflammatory pathway, lipid metabolism pathway, drug metabolism-cytochrome P450 pathway, cholesterol/bile acid metabolism pathway, and copper ion transport/metabolism pathway are compromised in the liver by two sizes of BSA@Cu2-xS NPs, while only SNPs show a complete recovery of altered gene expression after NPs discontinuation. This study demonstrates that the translational feasibility of small-sized BSA@Cu2-xS NPs as excellent nanoagents with manageable hepatotoxicity.

[Study on potential hepatotoxicity of main monomers of Polygonum multiflorum based on liver micro-tissue].

In this study, we aimed to establish a rat liver micro-tissue evaluation system to evaluate the hepatotoxicity of the main monomers in Polygonum multiflorum. Rat primary hepatocytes were isolated and purified by two-step in situ perfusion method to prepare hepatic parenchymal cells. The ultra-low adsorption plate and the inverted model were used to establish an in vitro hepatotoxicity evaluation system. After the system was established, the main monomer components(monanthone with emodin type, rhein, emodin, emodin-8-O-ß-D-glucopyranoside, physcion) of P. multiflorum were selected for in vitro hepatotoxicity evaluation. This study showed that the primary cells of the liver can form liver micro-tissues in the low adsorption plate method and the mold perfusion method, with good liver structure and function, which can be used to evaluate the hepatotoxicity of the drug to be tested after long-term administration. The five monomers to be tested in P. multiflorum can significantly affect the proliferation of primary liver micro-tissues in rats in a dose-and time-dependent manner. The hepatotoxic effects were as follows: monanthone with emodin type > rhein > emodin > emodin-8-O-ß-D-glucopyranoside > physcion. The results suggested that the emodin-type monoterpene and rhein might be the potential hepatotoxic components, while the metabolites of emodin-8-O-ß-D-glucoside and emodin methyl ether showed more toxic risks. The rat primary hepatocyte micro-tissue model system established in this experiment could be used to achieve long-term drug administration in vitro, which was consistent with the clinical features of liver injury caused by long-term use of P. multiflorum. The experimental results provided important information and reference on the clinical application and toxic component of P. multiflorum.

[Biomechanical research of transforaminal lumbar interbody fusion model].

Based on the surgical model using transforaminal lumbar interbody fusion (TLIF) to treat lumbar spondylolisthesis, this paper presents the investigations of the biomechanical characteristics of cage and pedicle screw in lumbar spinal fusion implant fixed system under different combinations with finite element method. Firstly, combining the CT images with finite element pretreatment software, we established three dimensional nonlinear finite element model of human lumbar L4-L5 segmental slight slippage and implant under different fixed combinations. We then made a comparison analysis between the biomechanical characteristics of lumbar motion range, stress distribution of cage and pedicle screw under six status of each model which were flexion, extension, left lateral bending, right lateral bending, left axial rotation and right axial rotation. The results showed that the motion ranges of this model under different operations were reduced above 84% compared with those of the intact model, and the stability of the former was improved significantly. The stress values of cage and pedicle screw were relatively larger when they were fixed by single fusion device additional unilateral pedicle screw, but there was no statistically significant difference. The above research results would provide reference and confirmation for further biomechanics research of TLIF extracorporal specimens, and finally provide biomechanical basis for the feasibility of unilateral internal fixed diagonal intervertebral fusion TLIF surgery.

[Construction and analysis of a finite element model of human L4-5 lumbar segment].

In the present study, a finite element model of L4-5 lumbar motion segment was established based on the CT images and a combination with image processing software, and the analysis of lumbar biomechanical characteristics was conducted on the proposed model according to different cases of flexion, extension, lateral bending and axial rotation. Firstly, the CT images of lumbar segment L4 to L5 from a healthy volunteer were selected for a three dimensional model establishment which was consisted of cortical bone, cancellous bone, posterior structure, annulus, nucleus pulposus, cartilage endplate, ligament and facet joint. The biomechanical analysis was then conducted according to different cases of flexion, extension, lateral bending and axial rotation. The results showed that the established finite element model of L4-5 lumbar segment was realistic and effective. The axial displacement of the proposed model was 0.23, 0.47, 0.76 and 1.02 mm, respectively under the pressure of 500, 1 000, 1 500 and 2 000 N, which was similar to the previous studies in vitro experiments and finite element analysis of other people under the same condition. The stress distribution of the lumbar spine and intervertebral disc accorded with the biomechanical properties of the lumbar spine under various conditions. The established finite element model has been proved to be effective in simulating the biomechanical properties of lumbar spine, and therefore laid a good foundation for the research of the implants of biomechanical properties of lumbar spine.

Mechanoimmune-Driven Backpack Sustains Dendritic Cell Maturation for Synergistic Tumor Radiotherapy.

Cell backpacks present significant potential in both therapeutic and diagnostic applications, making it essential to further explore their interactions with host cells. Current evidence indicates that backpacks can induce sustained immune responses. Our original objective was to incorporate a model antigen into the backpacks to promote dendritic cell maturation and facilitate antigen presentation, thereby inducing immune responses. However, we unexpectedly discovered that both antigen-loaded backpacks and empty backpacks demonstrated comparable abilities to induce dendritic cell maturation, resulting in nearly identical potency in T-cell proliferation. Our mechanistic studies suggest that the attachment of backpacks induces mechanical forces on dendritic cells via opening the PIEZO1 mechanical ion channel. This interaction leads to the remodeling of the intracellular cytoskeleton and facilitates the production of type I interferons by dendritic cells. Consequently, the mechano-immune-driven dendritic cell backpacks, when combined with radiotherapy, induce a robust antitumor effect. This research presents an avenue for leveraging mechanotransduction to enhance combination immunotherapeutic strategies, potentially leading to groundbreaking advancements in the field.

Mechanistic study for drug induced cholestasis using batch-fabricated 3D spheroids developed by agarose-stamping method.

Cell spheroid culture can recapitulate the tissue microstructure and cellular responses in vivo. While there is a strong need to understand the modes of toxic action using the spheroid culture method, existing preparation techniques suffer from low efficiency and high cost. Herein, we developed a metal stamp containing hundreds of protrusions for batch bulk preparation of cell spheroids in each well of the culture plates. The agarose matrix imprinted by the stamp can form an array of hemispherical pits, which facilitated the fabrication of hundreds of uniformly sized rat hepatocyte spheroids in each well. Chlorpromazine (CPZ) was used as a model drug to investigate the mechanism for drug induced cholestasis (DIC) by agarose-stamping method. Hepatocyte spheroids showed a more sensitive detection of hepatotoxicity compared to 2D and Matrigel-based culture systems. Cell spheroids were also collected for staining of cholestatic protein and showed a CPZ-concentration-dependent decrease of bile acid efflux related proteins (BSEP and MRP2) and tight junction (ZO-1). In addition, the stamping system successfully delineated the DIC mechanism by CPZ that may be associated with the phosphorylation of MYPT1 and MLC2, two central proteins in the Rho-associated protein kinase pathway (ROCK), which were significantly attenuated by ROCK inhibitors. Our results demonstrated a large-scale fabrication of cell spheroids by the agarose-stamping method, with promising benefits for exploring the mechanisms for drug hepatotoxic responses.

Bismuth nanomaterials as contrast agents for radiography and computed tomography imaging and their quality/safety considerations.

Contrast agents for radiography and computed tomography (CT) scans are substances that can enhance the contrast of blood vessels and soft tissue with detailed imaging information of the diseased sites. However, the large doses, short circulation time and adverse effects are the intrinsic limitations of CT contrast agents, preventing their extended and safe use in the clinical setting. Bismuth nanoparticles (NPs) have gained attention for the high X-ray absorption of bismuth elements with acceptable biocompatibility, showing their potential to be translated into commercialized CT contrast agents. Compared with traditional iodine contrast agents, bismuth NPs are characterized by prolonged circulation time and enhanced contrast, largely due to the surface modification and enhanced permeability and retention effect of NPs. Bismuth NPs can also be flexibly upgraded into sophisticated nanoagents for multimodal imaging and therapeutic purposes by complexation with supporting chemicals, small molecule drugs, fluorescence labels, and other functional agents. Additionally, the affinity and retention of the bismuth NPs in the diseased sites can be further improved by modification of the targeting moiety on the NPs surface. However, a simple synthetic process and low complexity of bismuth NPs are highly recommended for scaling out and quality control of nanoagents with commercialization potential. Since product safety is a prerequisite for the translation of bismuth NPs from bench to the clinic, we focus on recent advances in the distribution, elimination, and toxicity of bismuth NPs previously reported. Finally, we delineate the associated mechanisms for nephrotoxicity and the strategy to reduce the toxicity of bismuth NPs. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials.

Hepatotoxicity of copper sulfide nanoparticles towards hepatocyte spheroids using a novel multi-concave agarose chip method.

Aim: To explore the hepatotoxicity of copper sulfide nanoparticles (CuSNPs) toward hepatocyte spheroids. Materials & methods: Other than the traditional agarose method to generate hepatocyte spheroids, we developed a multi-concave agarose chip (MCAC) method to investigate changes in hepatocyte viability, morphology, mitochondrial membrane potential, reactive oxygen species and hepatobiliary transporter by CuSNPs. Results: The MCAC method allowed a large number of spheroids to be obtained per sample. CuSNPs showed hepatotoxicity in vitro through a decrease in spheroid viability, albumin/urea production and glycogen deposition. CuSNPs also introduced hepatocyte spheroid injury through alteration of mitochondrial membrane potential and reactive oxygen species, that could be reversed by N-acetyl-l-cysteine. CuSNPs significantly decreased the activity of BSEP transporter by downregulating its mRNA and protein levels. Activity of the MRP2 transporter remained unchanged. Conclusion: We observed the hepatotoxicity of CuSNPs in vitro with associated mechanisms in an advanced 3D culture system.