Evaluation of superparamagnetic iron oxide-polymer composite microcapsules for magnetic resonance-guided high-intensity focused ultrasound cancer surgery.

BACKGROUND: Superparamagnetic poly (lactic-co-glycolic acid) (PLGA)-coated Fe3O4 microcapsules are receiving increased attention as potential diagnostic and therapeutic modalities in the field of oncology. In this study, PLGA-coated Fe3O4 microcapsules were combined with a magnetic resonance imaging-guided high-intensity focused ultrasound (MR-guided HIFU) platform, with the objective of investigating the effects of these composite microcapsules regarding MR-guided HIFU liver cancer surgery in vivo. METHODS: PLGA-coated Fe3O4 microcapsules consisting of a liquid core and a PLGA-Fe3O4 shell were fabricated using a modified double emulsion evaporation method. Their acute biosafety was confirmed in vitro using MDA cells and in vivo using rabbits. To perform MR-guided HIFU surgery, the microcapsules were intravenously injected into a rabbit liver tumor model before MR-guided HIFU. T2-weighted images and MR signal intensity in normal liver parenchyma and tumor tissue were acquired before and after injection, to assess the MR imaging ability of the microcapsules. After MR-guided HIFU ablation tissue temperature mapping, the coagulative volume and histopathology of the tumor tissue were analyzed to investigate the ablation effects of MR-guided HIFUs. RESULTS: Scanning and transmission electron microscopy showed that the microcapsules displayed a spherical morphology and a shell-core structure (mean diameter, 587 nm). The hysteresis curve displayed the typical superparamagnetic properties of the microcapsules, which are critical to their application in MR-guided HIFU surgery. In MR-guided HIFU surgery, these microcapsules functioned as an MRI contrast agent, induced significant hyperthermal enhancement (P < 0.05) and significantly enhanced the volume of coagulative necrosis (P < 0.05). CONCLUSIONS: The administration of PLGA-coated Fe3O4 microcapsules is a potentially synergistic technique regarding the enhancement of MR-guided HIFU cancer surgery.

Treated dentin matrix induces odontogenic differentiation of dental pulp stem cells via regulation of Wnt/ß-catenin signaling.

Treated dentin matrix (TDM) is an ideal scaffold material containing multiple extracellular matrix factors. The canonical Wnt signaling pathway is necessary for tooth regeneration. Thus, this study investigated whether the TDM can promote the odontogenic differentiation of human dental pulp stem cells (hDPSCs) and determined the potential role of Wnt/ß-catenin signaling in this process. Different concentrations of TDM promoted the dental differentiation of the hDPSCs and meanwhile, the expression of GSK3ß was decreased. Of note, the expression of the Wnt/ß-catenin pathway-related genes changed significantly in the context of TDM induction, as per RNA sequencing (RNA seq) data. In addition, the experiment showed that new dentin was visible in rat mandible cultured with TDM, and the thickness was significantly thicker than that of the control group. In addition, immunohistochemical staining showed lower GSK3ß expression in new dentin. Consistently, the GSK3ß knockdown hDPSCs performed enhanced odotogenesis compared with the control groups. However, GSK3ß overexpressing could decrease odotogenesis of TDM-induced hDPSCs. These results were confirmed in immunodeficient mice and Wistar rats. These suggest that TDM promotes odontogenic differentiation of hDPSCs by directly targeting GSK3ß and activating the canonical Wnt/ß-catenin signaling pathway and provide a theoretical basis for tooth regeneration engineering.

Inhibitory effect of the TSG-6 on the BMP-4/Smad signaling pathway and odonto/osteogenic differentiation of dental pulp stem cells.

This study aimed to observe the molecular mechanism underlying the effect of tumor necrosis factor-inducible protein 6 (TSG-6) on the bone morphogenetic protein-4 (BMP-4)/drosophila mothers against decapentaplegic protein(Smad) signaling pathway and mineralization of dental pulp stem cells (DPSCs) in inflammatory environment. Normal and TSG-6 gene-modified DPSCs were cultured in a mineralization-inducing fluid containing 0 or 50 ng/mL TNF-α separately. The real-time polymerase chain reaction was used to measure the expression of TSG-6 and odonto/osteogenic differentiation makers at the mRNA level. Western blot analysis and cellular immunofluorescence were used to observe the odonto/osteogenic differentiation of DPSCs and the variation of BMP-4/Smad signaling pathway at the protein level. Moreover, normal and modified DPSCs combined with hydrogel were used for subcutaneous implantation in nude mice. The levels of odonto/osteogenic markers and BMP-4/Smad-related proteins were lower in Ad-TSG-6 DPSCs than in normal DPSCs after mineralization induction, and were higher in TSG-6-RNAi DPSCs than in normal DPSCs after culturing with mineralization-inducing fluid containing 50 ng/mL TNF-α. The subcutaneous transplantation of normal and modified DPSCs combined with hydrogel in nude mice demonstrated that normal DPSCs were formed in the tissue containing collagen. The tissue formed by Ad-TSG-6 DPSCs was highly variable, and the cells were very dense. We can know that TNF-α regulates the expression of TSG-6, thereby inhibiting the BMP-4/Smad signaling pathway and the odonto/osteogenic differentiation ability of DPSCs.

R-Spondin 2 Induces Odontogenic Differentiation of Dental Pulp Stem/Progenitor Cells via Regulation of Wnt/ß-Catenin Signaling.

Odontoblast cells generated from human dental pulp stem/progenitor cells (hDPSCs) secrete reparative dentin in responds to an injury. Endogenous Wnt signaling is also activated during this process, and these Wnt-activated cells are responsible for the following repair response. R-spondin 2 (Rspo2) is a potent stem cell growth factor, which strongly potentiates Wnt/ß-catenin signaling and plays a vital role in cell differentiation and regeneration. However, the role of Rspo2 during odontoblast differentiation in hDPSCs has not yet been completely understood. This study investigated the effects of Rspo2 on hDPSCs to provide therapeutic insight into dentin regeneration and reparative dentin formation. HDPSCs were extracted from human molars or premolars. Immunofluorescence staining and flow cytometric analysis were used to detect the mesenchymal stem cell markers in hDPSCs. EdU assay and Cell Counting Kit-8 (CCK-8) were performed to explore cell proliferation. The odontogenic differentiation levels were determined by measuring the mRNA and protein expression of DSPP, DMP-1, ALP, and BSP. Immunofluorescence staining was performed to detect the localization of ß-catenin. The biological effects of Rspo2 on hDPSCs was investigated using the Lentivirus-based Rspo2 shRNA and recombined human Rspo2 (rhRspo2). Recombined human DKK-1 (rhDKK-1) and recombined human Wnt3a (rhWnt3a) were used for further investigation. The cells generated from human dental pulp expressed mesenchymal stem cell markers Vimentin, Stro-1, Nestin, C-kit, CD90, and CD73, while were negative for CD3, CD31, and CD34. The mRNA expression levels of the odontogenic-related genes DSPP, DMP-1, ALP, and BSP were upregulated in the rhRspo2 treated cells. Silencing Rspo2 suppressed the proliferation and differentiation of the hDPSCs. Blockade of Wnt signaling with DKK-1 inhibited Rspo2-induced activation of Wnt/ß-catenin signaling and cell differentiation. The combined use of rhWnt3a and rhRspo2 created a synergistic effect to improve the activation of Wnt/ß-catenin signaling. Rspo2 promoted the proliferation and odontogenic differentiation of hDPSCs by regulating the Wnt/ß-catenin signaling pathway.

Establishment of an Experimental Intracerebral Haemorrhage Model for Mass Effect Research using a Thermo-sensitive Hydrogel.

The mechanical response of brain tissue closely relates to cerebral blood flow and brain diseases. During intracerebral haemorrhage (ICH), a mass effect occurs during the initial bleeding and results in significant tissue deformation. However, fewer studies have focused on the brain damage mechanisms and treatment approaches associated with mass effects compared to the secondary brain injuries after ICH, which may be a result of the absence of acceptable animal models mimicking a mass effect. Thus, a thermo-sensitive poly (N-isopropylacrylamide) (PNIPAM) hydrogel was synthesized and injected into the rat brain to establish an ICH model for mass effect research. The PNIPAM hydrogel or autologous blood was injected to establish an ICH animal model, and the space-occupying volumes, brain tissue elasticity, brain oedema, neuronal cell death, iron deposition and behavioural recovery were evaluated. The lower critical solution temperature of PNIPAM hydrogel was 32 °C, and the PNIPAM hydrogel had a rough surface with similar topography and pore structure to a blood clot. Furthermore, the ICH model animals who received an injection of PNIPAM and blood produced similar lesion volumes, elasticity changes and mechanically activated ion channel piezo-2 upregulation in brain tissue. Meanwhile, slight iron deposition, neuronal cell death and brain oedema were observed in the PNIPAM hydrogel model compared to the blood model. In addition, the PNIPAM hydrogel showed good biocompatibility and stability in vivo via subcutaneous implantation. Our findings show that PNIPAM hydrogel cerebral infusion can form a mass effect similar to haematoma and minimize the interference of blood, and the establishment of a mass effect ICH model is beneficial for understanding the mechanism of primary brain injury and the role of mass effects in secondary brain damage after ICH.

Folate-receptor-targeted laser-activable poly(lactide-co-glycolic acid) nanoparticles loaded with paclitaxel/indocyanine green for photoacoustic/ultrasound imaging and chemo/photothermal therapy.

BACKGROUND: Cancer is one of the most serious threats to human health. Precision medicine is an innovative approach to treatment, as part of which theranostic nanomedicine has been studied extensively. However, the required biocompatibility and substantial cost for the approval of nanomedicines hinder their clinical translation. PURPOSE: We designed a novel type of theranostic nanoparticle (NP) folate-receptor-targeted laser-activatable poly(lactide-co-glycolic acid) (PLGA) NPs loaded with paclitaxel (Ptx)/indo-cyanine green (ICG)-folic acid-polyethylene glycol (PEG)-PLGA-Ptx@ICG-perfluorohexane (Pfh)- using safe and approved materials and drugs, which would facilitate clinical translation. With laser irradiation, highly efficient photothermal therapy can be achieved. Additionally, targeted NPs can be activated by near-infrared laser irradiation at a specific region, which leads to the sharp release of Ptx at areas of high folate-receptor expression and ensures a higher Ptx concentration within the tumor region, thereby leading to chemo/photothermal synergistic antitumor efficacy. Meanwhile, the NPs can be used as a dual-modality contrast agent for photoacoustic and ultrasound imaging. MATERIALS AND METHODS: FA-PEG-PLGA-Ptx@ICG-Pfh NPs were prepared by sonification method and characterized for physicochemical properties. Cytotoxicity and in vivo biocompatibility were evaluated respectively by CCK8 assay and blood analysis. NPs as dual-modality contrast agents were evaluated by photoacoustic/ultrasound imaging system in vitro and in vivo. In vitro anticancer effect and in vivo anticancer therapy was evaluated by CCK8 assay and MDA-MB231 tumor-bearing mice model. RESULTS: FA-PEG-PLGA-Ptx@ICG-Pfh NPs were in the size of 308±5.82 nm with negative zeta potential and showed excellent photothermal effect. The NPs could be triggered sharp release of Ptx by laser irradiation, and showed the good biocompatibility in vitro and in vivo. Through photoacoustic/ultrasound imaging, the NPs showed an excellent ability as dual-modality contrast agents in vitro and in vivo. FA-PEG-PLGA-Ptx@ICG-Pfh NPs with laser irradiation showed the best anticancer efficacy in vitro and in vivo. CONCLUSION: Such a biocompatible and novel theranostic NP is expected to integrate dual-modality imaging with improved therapeutic efficacy and provide a promising paradigm for cancer therapy.

[Clinic analysis of 198 elder patients with maxillofacial fracture].

OBJECTIVE: The purpose of the study was to analyze the characteristics of elder patients with maxillofacial fracture. METHODS: We retrospectively analyzed the characteristics of maxillofacial fractures in the elder patients, who were treated from July 2010 to October 2017. The clinical characteristics of the etiology, fracture site, combined injury, systemic disease, and treatment method were analyzed. RESULTS: In the 198 elderly patients with maxillofacial fractures, the male-to-female ratio was 3.95︰1, and the mean age was 66.15 years old. Traffic accident injury (78 patients, 39.39%), fall injury (49 patients, 24.75%), high fall injury (33 patients, 16.67%) were the main factors of maxillofacial fracture in elderly patients. The most frequently observed fracture site was the mandible (120 patients). A total of 60 patients demonstrated associated injuries, in which limb injuries were the most prevalent (28 patients); whereas 66 patients had other systemic medical conditions, in which cardiovascular diseases was the most frequent (50 patients). The main treatment method of 198 patients was rigid internal fixation with small or micro-plates. CONCLUSIONS: Falling and traffic accidents are the main factors of maxillofacial fracture in elderly patients. Thus, interference measures should be observed for the prevention of maxillofacial fractures in elderly patients.

Low-intensity focused ultrasound mediated localized drug delivery for liver tumors in rabbits.

OBJECTIVE: To explore the antitumor effects of low-intensity focused ultrasound (LIFU) mediated localized drug delivery of adriamycin-microbubble-PLGA nanoparticle complexes on rabbits VX2 liver tumor. METHODS: ADM-NMCs were prepared by covalent linking of ADM-PLGA nanoparticles (ADM-NPs) to the shell of the microbubbles. A fixed water bag filled with microbubbles was subjected to LIFU and non-focused ultrasound respectively, and the ultrasound images of which were recorded before and after ultrasonication. A total of 54 VX2 liver tumor-burdened rabbits were divided into six groups randomly, including control, ADM-NPs combined with LIFU, microbubbles combined with LIFU, ADM-NPs and microbubbles combined with LIFU, ADM-NMCs combined with LIFU and ADM-NMCs combined with Non-FUS. The tumor volume and volume inhibition rate (VIR) of tumor progression were calculated and compared. Apoptotic cells were labeled by terminal deoxyuridine nick end. Proliferating cell nuclear antigen was detected by immunohistochemistry. The median survival time of the animals were recorded and compared. RESULTS: ADM-NMCs were successfully prepared with an average diameter of 1721 nm. The highest VIR and apoptotic index (AI) were found in the group of ADM-NMCs combined with LIFU while the lowest proliferating index (PI) was simultaneously observed in this group. The median survival time of the rabbits in the ADM-NMCs combined with LIFU group was the longest (71days) among all groups. CONCLUSIONS: ADM-NMCs combined with LIFU could inhibit the rabbits VX2 liver tumor progress by delaying the tumor proliferation and accelerating apoptosis, which presents a novel process for liver tumor targeting chemotherapy.