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The gut microbiome is linked to osteoporosis. Previous clinical studies showed inconsistent results. This study aimed to characterize the gut microbiota feature and reveal its relation with diet in postmenopausal osteoporosis. Fifty-five postmenopausal women with osteoporosis (Op group) and forty-four age-matched postmenopausal women (normal bone mineral density, Con group) were included in this study. Fecal microbiota was collected and analyzed by shallow shotgun sequencing. Food frequency questionnaires were collected from both groups, and Spearman analysis was used to clarify its correlation with gut microbiota. A total of 2671 species from 29 phyla, 292 families, 152 orders, 80 classes were detected in the study. The two groups had no significant difference in the α and β diversity (p > 0.05). At the genus level, Anaerostipes was enriched in Op group (p < 0.05). At species level, Methanobrevibacter smithii, Bifidobacterium animalis, Rhodococcus defluvii, Lactobacillus plantarum, and Carnobacterium mobile were enriched in the Op group, while Bacillus luciferensis, Acetivibrio cellulolyticus, Citrobacter amalonaticus, and Bifidobacterium breve were differentially enriched in the Con group. Food frequency questionnaire showed that postmenopausal women with osteoporosis intaked more red meat, beer, white and red wine (p < 0.05), and the Con group had more yogurt, fruit, and tea consumption. Red meat consumption had a significant negative correlation with Streptosporangiales (p < 0.01) and Actinomadura (p < 0.05). Fruits intake negatively correlated with Nocardiaceae, Rhodococcus, and Rhodococcus defluvii (p < 0.05). More yogurt intake was consistently correlated with a greater abundance of Streptosporangiales. This study suggests that gut microbiota is significantly altered in the postmenopausal osteoporosis population at genus and species levels, and specific dietary intake might relate to these changes., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Indoleamine-2,3-dioxygenase-1 (IDO1) pathogenically suppresses immune cell infiltration and promotes tumor cell immune escape by overmetabolizing tryptophan to N -formyl kynurenine in the tumor microenvironment (TME). However, it remains challenging for IDO1 immune checkpoint inhibitors to achieve a significant potency of progression-free survival. Here, we developed a breakthrough in IDO1 inhibition by sono-targeted biobromination reaction using immunostimulating hypobromic- P -phenylperoxydibenzoic acid-linked metallic organic framework nanomedicine (H-MOF NM) to remodel the TME from debrominated hypoxia into hypobromated normoxia and activate the IDO1 immune pathway with in vitro and in vivo remarkable antitumor efficacy. H-MOF NM contains Br + and O - active ingredients with an enlarged band gap to deactivate IDO1 through an innovative biochemical mechanism, taking control over brominating IDO1 amino acid residues at the active sites in the remodeled TME and subsequently activating the immune response, including DC maturation, T-cell activation, and macrophage polarization. Importantly, the H-MOF NM achieves multiple immune responses with high tumor regression potency by combination sono-immunotherapy. This study describes an excellent IDO1 inhibition strategy through the development of immune biobrominative H-MOF nanomedicine and highlights efficient combination immunotherapy for tumor treatment.

Tumor microenvironment (TME) plays an important role in the tumor progression. Among TME components, cancer-associated fibroblasts (CAFs) show multiple tumor-promoting effects and can induce tumor immune evasion and drug-resistance. Regulating CAFs can be a potential strategy to augment systemic anti-tumor immunity. Here, the study observes that hydrogen treatment can alleviate intracellular reactive oxygen species of CAFs and reshape CAFs' tumor-promoting and immune-suppressive phenotypes. Accordingly, a controllable and TME-responsive hydrogen therapy based on a CaCO 3 nanoparticles-coated magnesium system (Mg-CaCO 3 ) is developed. The hydrogen therapy by Mg-CaCO 3 can not only directly kill tumor cells, but also inhibit pro-tumor and immune suppressive factors in CAFs, and thus augment immune activities of CD4 + T cells. As implanted in situ, Mg-CaCO 3 can significantly suppress tumor growth, turn the "cold" primary tumor into "hot", and stimulate systematic anti-tumor immunity, which is confirmed by the bilateral tumor transplantation models of "cold tumor" (4T1 cells) and "hot tumor" (MC38 cells). This hydrogen therapy system reverses immune suppressive phenotypes of CAFs, thus providing a systematic anti-tumor immune stimulating strategy by remodeling tumor stromal microenvironment., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

The essential role of the neural network in enhancing bone regeneration has often been overlooked in biomaterial design, leading to delayed or compromised bone healing. Engineered mesenchymal stem cells (MSCs)-derived exosomes are becoming increasingly recognized as potent cell-free agents for manipulating cellular behavior and improving therapeutic effectiveness. Herein, MSCs are stimulated with nerve growth factor (NGF) to regulate exosomal cargoes to improve neuro-promotive potential and facilitate innervated bone regeneration. In vitro cell experiments showed that the NGF-stimulated MSCs-derived exosomes (N-Exos) obviously improved the cellular function and neurotrophic effects of the neural cells, and consequently, the osteogenic potential of the osteo-reparative cells. Bioinformatic analysis by miRNA sequencing and pathway enrichment revealed that the beneficial effects of N-Exos may partly be ascribed to the NGF-elicited multicomponent exosomal miRNAs and the subsequent regulation and activation of the MAPK and PI3K-Akt signaling pathways. On this basis, N-Exos were delivered on the micropores of the 3D-printed hierarchical porous scaffold to accomplish the sustained release profile and extended bioavailability. In a rat model with a distal femoral defect, the N-Exos-functionalized hierarchical porous scaffold significantly induced neurovascular structure formation and innervated bone regeneration. This study provided a feasible strategy to modulate the functional cargoes of MSCs-derived exosomes to acquire desirable neuro-promotive and osteogenic potential. Furthermore, the developed N-Exos-functionalized hierarchical porous scaffold may represent a promising neurovascular-promotive bone reparative scaffold for clinical translation.

Marrow niches in osteosarcoma (OS) are a specialized microenvironment that is essential for the maintenance and regulation of OS cells. However, existing animal xenograft models are plagued by variability, complexity, and high cost. Herein, we used a decellularized osteosarcoma extracellular matrix (dOsEM) loaded with extracellular vesicles from human bone marrow-derived stem cells (hBMSC-EVs) and OS cells as a bioink to construct a micro-osteosarcoma (micro-OS) through 3D printing. The micro-OS was further combined with a microfluidic system to develop into an OS-on-a-chip (OOC) with a built-in recirculating perfusion system. The OOC system successfully integrated bone marrow niches, cell‒cell and cell-matrix crosstalk, and circulation, allowing a more accurate representation of OS characteristics in vivo . Moreover, the OOC system may serve as a valuable research platform for studying OS biological mechanisms compared with traditional xenograft models and is expected to enable precise and rapid evaluation and consequently more effective and comprehensive treatments for OS., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Osteoporotic fracture is one of the most serious complications of osteoporosis. Most fracture sites have bone defects, and restoring the balance between local osteogenesis and bone destruction is difficult during the repair of osteoporotic bone defects. In this study, we successfully fabricated three-dimensional (3D)-printed biodegradable magnesium alloy (Mg-Nd-Zn-Zr) scaffolds and prepared a zoledronic acid-loaded ceramic composite coating on the surface of the scaffolds. The osteogenic effect of Mg and the osteoclast inhibition effect of zoledronic acid were combined to promote osteoporotic bone defect repair. In vitro degradation and drug release experiments showed that the coating significantly reduced the degradation rate of 3D-printed Mg alloy scaffolds and achieved a slow release of loaded drugs. The degradation products of drug-loaded coating scaffolds can promote osteogenic differentiation of bone marrow mesenchymal stem cells as well as inhibit the formation of osteoclasts and the bone resorption by regulating the expression of related genes. Compared with the uncoated scaffolds, the drug-coated scaffolds degraded at a slower rate, and more new bone grew into these scaffolds. The healing rate and quality of the osteoporotic bone defects significantly improved in the drug-coated scaffold group. This study provides a new method for theoretical research and clinical treatment using functional materials for repairing osteoporotic bone defects., Competing Interests: The authors declare no conflict of interest.., (Copyright:© 2023, Ran Z, Wang Y, Li J, et al.)

3D-printed biofunctional scaffolds have promising applications in bone tissue regeneration. However, the development of bioinks with rapid internal vascularization capabilities and relatively sustained osteoinductive bioactivity is the primary technical challenge. In this work, we added rat platelet-rich plasma (PRP) to a methacrylated gelatin (GelMA)/methacrylated alginate (AlgMA) system, which was further modified by a nanoclay, laponite (Lap). We found that Lap was effective in retarding the release of multiple growth factors from the PRP-GelMA/AlgMA (PRP-GA) hydrogel and sustained the release for up to 2 weeks. Our in vitro studies showed that the PRP-GA@Lap hydrogel significantly promoted the proliferation, migration, and osteogenic differentiation of rat bone marrow mesenchymal stem cells, accelerated the formation of endothelial cell vascular patterns, and promoted macrophage M2 polarization. Furthermore, we printed hydrogel bioink with polycaprolactone (PCL) layer-by-layer to form active bone repair scaffolds and implanted them in subcutaneous and femoral condyle defects in rats. In vivo experiments showed that the PRP-GA@Lap/PCL scaffolds significantly promoted vascular inward growth and enhanced bone regeneration at the defect site. This work suggests that PRP-based 3D-bioprinted vascularized scaffolds will have great potential for clinical translation in the treatment of bone defects., Competing Interests: The authors declare no conflicts of interest., (Copyright:© 2023, Cao B, Lin J, Tan J, et al.)

Background: Existing state-of-the-art "safe zone" prediction methods are statistics-based methods, image-matching techniques, and machine learning methods. Yet, those methods bring a tension between accuracy and interpretability., Purpose: To explore the model explanations and estimator consensus for "safe zone" prediction., Material and Methods: We collected the pelvic datasets from Orthopaedic Hospital, and a novel acetabular cup detection method is proposed for automatic ROI segmentation. Hybrid priors comprising both specific priors from data and general priors from experts are constructed. Specifically, specific priors are constructed based on the fine-tuned ResNet-101 convolutional neural networks (CNN) model, and general priors are constructed based on expert knowledge. Our method considers the model explanations and dynamic consensus through appending a SHapley Additive exPlanations (SHAP) module and a dynamic estimator stacking., Results: The proposed method achieves an accuracy of 99.40% and an area under the curve of 0.9998. Experimental results show that our model achieves superior results to the state-of-the-art conventional ensemble classifiers and deep CNN models., Conclusion: This new screening model provides a new option for the "safe zone" prediction of acetabular cup.

Mechanical signals from extracellular matrix stiffness are important cues that regulate the proliferation and differentiation of bone marrow mesenchymal stem cells (BMSCs). However, the incorporation of BMSCs into soft hydrogels and the dominance of soft matrices for BMSC growth and differentiation limit the directed differentiation of BMSCs incorporated into hydrogels for tissue engineering, especially osteogenesis. Here, we found that the expression of miR-99b increased with increasing hydrogel stiffness and that miR-99b regulated the proliferation and differentiation of BMSCs seeded on the surface of substrates with different stiffnesses. Furthermore, miR-99b significantly promoted the migration of BMSCs in 3D hydrogels. Mechanistically, we demonstrated that matrix stiffness-sensitive miR-99b targets the mammalian target of the rapamycin signaling pathway to regulate the adipogenic and osteogenic differentiation of BMSCs. In addition, by modulating the expression of miR-99b, the osteogenic differentiation of BMSCs in soft 3D hydrogels was promoted. Consistently, the flexible BMSC-GelMA hydrogel transfected with miR-99b significantly promoted bone regeneration in the rat calvarial defect area. These results suggest that miR-99b plays a key role in the mechanotransduction and phenotypic transformation of BMSCs and may inspire new tissue engineering applications with MSCs as key components., (© 2023 Author(s).)

Osteoporosis results in decreased bone mass and insufficient osteogenic function. Existing titanium alloy implants have insufficient osteoinductivity and delayed/incomplete fracture union can occur when used to treat osteoporotic fractures. Copper ions have good osteogenic activity, but their dose-dependent cytotoxicity limits their clinical use for bone implants. In this study, titanium alloy implants functionalized with a TiCu/TiCuN coating by arc ion plating achieved a controlled release of copper ions in vitro for 28 days. The coated alloy was co-cultured with bone marrow mesenchymal stem cells and showed excellent biocompatibility and osteoinductivity in vitro . A further exploration of the underlying mechanism by quantitative real-time polymerase chain reaction and western blotting revealed that the enhancement effects are related to the upregulation of genes and proteins (such as axin2, β-catenin, GSK-3β, p-GSK-3β, LEF1 and TCF1/TCF7) involved in the Wnt/β-catenin pathway. In vivo experiments showed that the TiCu/TiCuN coating significantly promoted osteoporotic fracture healing in a rat femur fracture model, and has good in vivo biocompatibility based on various staining results. Our study confirmed that TiCu/TiCuN-coated Ti promotes osteoporotic fracture healing associated with the Wnt pathway. Because the coating effectively accelerates the healing of osteoporotic fractures and improves bone quality, it has significant clinical application prospects., (© The Author(s) 2022. Published by Oxford University Press.)

Background: Stable fixation is crucial in fracture treatment. Currently, optimal fracture fixation devices with osteoinductivity, mechanical compatibility, and corrosion resistance are urgently needed for clinical practice. Niobium (Nb), whose mechanical properties are similar to those of bone tissue, has excellent biocompatibility and corrosion resistance, so it has the potential to be the most appropriate fixation material for internal fracture treatment. However, not much attention has been paid to the use of Nb in the area of clinical implants. Yet its role and mechanism of promoting fracture healing remain unclear. Hence, this study aims at elucidating on the effectiveness of Nb by systematically evaluating its osteogenic performance via in vivo and ex vivo tests., Methods: Systematic in vivo and in vitro experiments were conducted to evaluate the osteogenic properties of Nb. In vitro experiments, the biocompatibility and osteopromoting activity of Nb were assessed. And the osteoinductive activity of Nb was assessed by alizarin red, ALP staining and PCR test. In vivo experiments, the effectiveness and biosafety of Nb in promoting fracture healing were evaluated using a rat femoral fracture model. Through the analysis of gene sequencing results of bone scab tissues, the upregulation of PI3K-Akt pathway expression was detected and it was verified by histochemical staining and WB experiments., Results: Experiments in this study had proved that Nb had excellent in-vitro cell adhesion and proliferation-promoting effects without cytotoxicity. In addition, ALP activity, alizarin red staining and semi-quantitative analysis in the Nb group had indicated its profound impact on enhancing osteogenic differentiation of MC3T3-E1 cells. We also found that the use of Nb implants can accelerate fracture healing compared to that with Ti6Al4V using an animal model of femur fracture in rats, and the biosafety of Nb was confirmed in vivo via histological evaluation. Furthermore, we found that the osteogenic effects of Nb were achieved through activation of the PIK/Akt3 signalling pathway., Conclusion: As is shown in the present research, Nb possessed excellent biosafety in clinical implants and accelerated fracture healing by activating the PI3K-Akt signalling pathway, which had good prospects for clinical translation, and it can replace titanium alloy as a material for new functional implants., Competing Interests: The authors have no conflicts of interest relevant to this article., (© 2022 Published by Elsevier B.V. on behalf of Chinese Speaking Orthopaedic Society.)

In this study, a femtosecond laser with a wavelength of 800 nm was used to modify the surface of a titanium alloy bone scaffold created via selective laser melting (SLM). The outcomes demonstrated that the surface morphology of the bone scaffold after femtosecond laser treatment was micro-nano morphology. The hydrophobic structure of the scaffold was changed into a super-hydrophilic structure, improving the surface roughness, which was highly helpful for osteoblast adhesion and differentiation. The femtosecond laser surface treatment in vitro samples produced a thick layer of hydroxyapatite (HAP) with improved surface bioactivity. The effectiveness of osseointegration and interstitial growth of the specimens treated with the femtosecond laser surface were found to be better when bone scaffolds were implanted into the epiphysis of the tibia of rabbits. As a result, femtosecond laser therapy dramatically enhanced the surface activity of bone scaffolds and their capacity to integrate with the surrounding bone tissues, serving as a trustworthy benchmark for future biological scaffold research., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Wang, Zhang, Liu, Xu, Huang, Shi, Liu, Li, Li, Hao and Hao.)

Trimethylamine-N-oxide (TMAO), an important gut microbiota (GM)-derived metabolite, has been shown to be abnormally increased in osteoporosis. However, the role and underlying mechanism of TMAO in regulating bone loss during osteoporosis have not been fully investigated. In the current study, we found that 100-400 μM TMAO dose-dependently enhanced TRAP-positive osteoclasts, F-actin ring formation, and resorption area on bovine bone slices and up-regulated osteoclast-related gene expression (Calcr, Traf6, Dcstamp, Acp5, C-Fos, and NFATc1). Western blotting validated that TMAO not only activated NF-κB signaling pathway but also stimulated c-Fos and NFATc1 protein expression in a dose-dependent manner. Furthermore, BAY 11-7082, an NF-κB inhibitor, pretreatment markedly suppressed TRAP-positive osteoclast formation and osteoclast-related genes under TMAO treatment. BAY 11-7082 also inhibited p-p65/p65, c-Fos, and NFATc1 protein expression promoted by TMAO. Moreover, TMAO significantly increased ROS production, which was inhibited by N-acetylcysteine (NAC), an ROS antagonist. In addition, we proved that NAC pretreatment could inhibit TMAO-promoted NF-κB activation. NAC also suppressed TRAP-positive osteoclast formation, osteoclast-related gene expression, and protein expression of c-Fos and NFATc1 under TMAO treatment. In vivo studies showed significantly decreased bone mass and increased TRAP-positive osteoclasts in TMAO-treated C57BL/6 mice. Moreover, western-blotting and immunohistochemical staining showed that TMAO administration markedly stimulated NF-κB p65 expression. Additionally, TMAO administration significantly promoted the gene and protein expression of C-Fos and NFATc1. In conclusion, TMAO could promote osteoclast differentiation and induce bone loss in mice by activating the ROS-dependent NF-κB signaling pathway.

Objective: The objective of the study was to investigate the effectiveness of applying the individualized guide plate which is based on digital image processing and 3D printing technology to percutaneous needle biopsy of periacetabular tumor. Methods: From July 2017 to August 2019, 11 patients (5 males and 6 females, aged 13-70 years, mean 42.3 years) with acetabular tumors diagnosed by needle biopsy in our hospital were enrolled in this retrospective study. Preoperative CT and MRI enhancement examination were performed routinely, and the DICOM data were collected and imported into Medraw Print software. According to the specific anatomical morphology of acetabula, this study adopted the reverse calculation and direct design to print the individualized puncture guide plate using 3D printing technology. The puncture point and sampling approaches were determined by the guide plate morphology and the "double guide-hole and slideable groove" design. First, we evaluated the fitness of the 3D guide plate to the local anatomical structure, its assisted-puncture accuracy was estimated by imaging examinations, and postoperative complications were recorded. The accuracy of the needle biopsy pathological result was estimated with reference to that of the tumor resection. Results: Our results showed that the 3D printing individualized guide plate matched the patients' pelvic skin well, the puncture approach was consistent with the preoperative design, and no significant anatomical injuries including vascular and neural complications occurred after surgery. Nine patients' (90%) biopsy results were consistent with their postoperative pathological results, and one patient gave up the tumor resection. Conclusion: Based on digital image processing and 3D printing technology, the individualized guide plate can be used to guide the needle biopsy of acetabular tumors which makes the operation simpler and more precise., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Wu, Liu, Wang, Wu, Zhao, Jiang, Dai, Hao, Fu and Ai.)

Sarcomas are rare malignant tumors that may arise from anywhere of the body, such as bone, adipose, muscle and vascular. However, the conventional pathogenesis of sarcomas has not been found. Therefore, there is an urgent need to identify novel therapeutic strategies and improve prognosis effects for sarcomas. Methylation of N6 adenosine (m6A) regulation is a novel proposed regulatory pattern that works in post-transcription level, which was also the most widely distributed methylation modification in eukaryotic mRNA. Growing evidences have demonstrated that m6A modification played an indispensable role in tumorigenesis. Here, we integrated multi-omics data including genetic alterations, gene expression and epigenomics regulation to systematically analysis the regulatory atlas of 21 m6A regulators in sarcoma. Firstly, we investigated the genetic alterations of m6A regulators and found that ~44% TCGA sarcoma patients have genetic mutations. We also investigated the basic annotation of 21 regulators, such as expression correlation and PPI interactions. Then we identified the upstream and downstream regulatory networks of between transcription factors (TFs)/non-coding RNAs and m6A regulators in sarcoma based on motif analysis and gene expression. These results implied that m6A regulator mediated regulatory axes could be used as prognostic biomarkers in sarcoma. Knockdown experiment results revealed that m6A regulators, YTHDF2 and HNRNPA2B1 participated in the cancer cell invasion and metastasis. Moreover, we also found that the expression levels of m6A regulators were related to immune cell infiltration of sarcoma patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Pang, Luo, Cao, Wu, Wang and Hao.)

Background: The rapid spread of infectious bacteria has brought great challenges to public health. It is imperative to explore effective and environment-friendly antibacterial modality to defeat antibiotic-resistant bacteria with high biosafety and broad-spectrum antibacterial property., Results: Herein, biocompatible Cu 3 SnS 4 nanoflakes (NFs) were prepared by a facile and low-cost fabrication procedure. These Cu 3 SnS 4 NFs could be activated by visible light, leading to visible light-mediated photocatalytic generation of a myriad of reactive oxygen species (ROS). Besides, the plasmonic Cu 3 SnS 4 NFs exhibit strong near infrared (NIR) absorption and a high photothermal conversion efficiency of 55.7%. The ROS mediated cellular oxidative damage and the NIR mediated photothermal disruption of bacterial membranes collaboratively contributed to the advanced antibacterial therapy, which has been validated by the efficient eradication of both Gram-negative Escherichia coli and Gram-positive methicillin-resistant Staphylococcus aureus strains in vitro and in vivo. Meanwhile, the exogenous copper ions metabolism from the Cu 3 SnS 4 NFs facilitated the endothelial cell angiogenesis and collagen deposition, thus expediting the wound healing. Importantly, the inherent localized surface plasmon resonance effect of Cu 3 SnS 4 NFs empowered them as an active substrate for surface-enhanced Raman scattering (SERS) imaging and SERS-labeled bacteria detection., Conclusions: The low cost and biocompatibility together with the solar-driven broad-spectrum photocatalytic/photothermal antibacterial property of Cu 3 SnS 4 NFs make them a candidate for sensitive bacteria detection and effective antibacterial treatment., (© 2022. The Author(s).)

Background: Thus far, the hip revision surgery has been widely used and promoted, and the technology has been constantly innovated, such as tissue engineering, 3D printing prosthesis, etc. However, traditional standardized prosthesis, allograft, autograft, bone cement and reinforcing ring are still the main treatment methods in the mainstream pelvic defects classification systems for hip revision. In addition, the mainstream classification systems are still mainly focus on the peri-acetabulum, but less on the large-scale complex pelvic defects that widely affecting the regions far away from the acetabulum, which also have a significant impact on the holistic biomechanical properties of pelvis., Methods: After integrating the design experience of custom prostheses and the understanding of biomechanical properties of pelvis, an innovative pelvic defects classification for custom revision was preliminarily proposed, and was practiced in surgeries. Some typical cases were chosen for elucidation in this study, and two observers each evaluated their CT data independently twice. Intraobserver and interobserver agreement were calculated using the kappa statistic to evaluate the reliability. The pelvis defects were classified into five types and two subtypes. The corresponding reconstruction principles, as the main basis to support the classification, were also described in detail. Prosthesis position examination and Harris hip score were utilized to evaluate the clinical outcome., Results: The installed prostheses resulted in high concordance with preoperative position planning, significantly improved Harris score, low postoperative complication rate and no re-revision case. In addition, The interobserver and intraobserver agreement were both excellent., Conclusion: The presenting revision system for complex pelvic defects utilizing 3D-printed custom prosthesis and corresponding classification of pelvic defects can preliminarily guide patients' grouping and prosthesis design, and may potentially provide an innovative, feasible, and efficient basis for complex total hip arthroplasty (THA) revision., Translational Potential Statement: This study provides a novel method for prosthetic revision of peri-acetabular pelvic defects, and is expected to systematically improve the efficiency of prosthesis design and surgery in clinical practice., (© 2021 The Authors.)

Osteosarcoma (OS) is the primary malignant bone tumor. Despite therapeutic strategies including surgery, chemotherapy, and radiotherapy have been introduced into the war of fighting OS, the 5-year survival rate for patients still remains unchangeable for decades. Besides, the critical bone defects after surgery, drug-resistance and side effects also attenuate the therapeutic effects and predict poor prognosis. Recently, photothermal therapy (PTT) has attracted extensive attention featuring minimal invasiveness and high spatial-temporal precision characteristics. Herein, an ultrathin 2D inorganic ancient pigment Egyptian blue decorated 3D-printing scaffold (CaPCu) with profound PTT efficacy at the second near-infrared (NIR-II) biowindow against OS and enhanced osteogenesis performance is successfully constructed. Importantly, this work uncovers the underlying biological mechanisms that genes associated with cell death, proliferation, and bone development are regulated by CaPCu-scaffold-based therapy. This work not only elucidates the fascinating clinical translation prospects of CaPCu-scaffold-based PTT against OS in NIR-II biowindow, but also demonstrates the potential mechanisms and offers a novel strategy to develop the next-generation, multifunctional tissue-engineering biomaterials., (© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Background and Objectives: The treatment of pelvic tumors is widely recognized to be challenging. The purpose of this study was to evaluate the efficacy of personalized three-dimensional (3D) printing-based limb salvage and reconstruction treatment for pelvic tumors., Methods: Twenty-eight pelvic tumor patients were enrolled. 3D printing lesion models and osteotomy templates were prepared for surgery planning, prosthesis design, and osteotomy assistance during surgery. 3D printing-based personalized pelvic prostheses were manufactured and used in all 28 patients. Follow-up of postoperative survival, prosthesis survival, imaging examinations, and Musculoskeletal Tumor Society (MSTS) lower limb functional scores were carried out., Results: The mean follow-up period was 32.2 months, during which 16 patients had disease-free survival, 3 survived with the disease, and 9 died. The prostheses were stable, and the mean offset of the center of rotation was 5.48 mm. The prosthesis-bone interface showed good integration. For the 19 surviving patients, the mean MSTS lower limb functional score was 23.2. Postoperative complications included superficial infection in six patients and hip dislocation in three patients., Conclusions: Personalized 3D printing-based limb salvage and reconstruction was an effective treatment for pelvic tumors. Our patients achieved good early postoperative efficacy and functional recovery., (© 2021 Wiley Periodicals LLC.)

Magnesium (Mg) alloys that have both antibacterial and osteogenic properties are suitable candidates for orthopedic implants. However, the fabrication of ideal Mg implants suitable for bone repair remains challenging because it requires implants with interconnected pore structures and personalized geometric shapes. In this study, we fabricated a porous 3D-printed Mg-Nd-Zn-Zr (denoted as JDBM) implant with suitable mechanical properties using selective laser melting technology. The 3D-printed JDBM implant exhibited cytocompatibility in MC3T3-E1 and RAW267.4 cells and excellent osteoinductivity in vitro . Furthermore, the implant demonstrated excellent antibacterial ratios of 90.0% and 92.1% for methicillin-resistant S. aureus (MRSA) and Escherichia coli , respectively. The 3D-printed JDBM implant prevented MRSA-induced implant-related infection in a rabbit model and showed good in vivo biocompatibility based on the results of histological evaluation, blood tests, and Mg 2+ deposition detection. In addition, enhanced inflammatory response and TNF-α secretion were observed at the bone-implant interface of the 3D-printed JDBM implants during the early implantation stage. The high Mg 2+ environment produced by the degradation of 3D-printed JDBM implants could promote M1 phenotype of macrophages (Tnf, iNOS, Ccl3, Ccl4, Ccl5, Cxcl10, and Cxcl2), and enhance the phagocytic ability of macrophages. The enhanced immunoregulatory effect generated by relatively fast Mg 2+ release and implant degradation during the early implantation stage is a potential antibacterial mechanism of Mg-based implant. Our findings indicate that 3D-printed porous JDBM implants, having both antibacterial property and osteoinductivity, hold potential for future orthopedic applications., Competing Interests: All authors have read and approved the manuscript and have no conflicts of interest to disclose., (© 2021 The Authors.)

Mesenchymal stem cells (MSCs) secrete paracrine trophic factors that are beneficial for tissue regeneration. In this study, a sponge-like scaffold with hierarchical and interconnected pores was developed using low-temperature deposition modeling (LDM) printing. Its effects on the cellular behavior, especially on the paracrine secretion patterns of MSCs, were comprehensively investigated. We found that compared with the scaffolds printed via the fused deposition modeling (FDM) technique, the LDM-printed sponges enhanced the adhesion, retention, survival, and ingrowth of MSCs and promoted cell-material interactions. Moreover, the paracrine functions of the cultured MSCs on the LDM-printed sponges were improved, with significant secretion of upregulated immunomodulatory, angiogenic, and osteogenic factors. MSCs on the LDM-printed sponges exert beneficial paracrine effects on multiple regenerative processes, including macrophage polarization, tube formation, and osteogenesis, verifying the enhanced immunomodulatory, angiogenic, and osteogenic potential. Further protein function assays indicated that focal adhesion kinase (FAK), downstream AKT, and yes-associated-protein (YAP) signaling might participate in the required mechanotransductive pathways, through which the hierarchical porous structures stimulated the paracrine effects of MSCs. In a rat distal femoral defect model, the MSC-laden LDM-printed sponges significantly promoted vascularized bone regeneration. The results of the present study demonstrate that the hierarchical porous biomimetic sponges prepared via LDM printing have potential applications in tissue engineering based on their cell-material interaction promotion and MSC paracrine function modulation effects. Furthermore, our findings suggest that the optimization of biomaterial properties to direct the paracrine signaling of MSCs would enhance tissue regeneration., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Long-term survival is still low for high-risk patients with soft tissue sarcoma treated with standard management options, including surgery, radiation, and chemotherapy. Immunotherapy is a promising new potential treatment paradigm. However, the application of immune checkpoint inhibitors for the treatment of patients with sarcoma did not yield promising results in a clinical trial. Therefore, there is a considerable need to identify factors that may lead to immune checkpoint inhibitor resistance., Methods: In this study, we performed a bioinformatic analysis of The Cancer Genome Atlas (TCGA) to detect key long noncoding RNAs (lncRNAs) that were correlated with immune checkpoint inhibitory molecules in sarcoma. The expression levels of these lncRNAs and their correlation with patient prognosis were explored. The upstream long noncoding RNAs were also examined via 450K array data from the TCGA. The potential roles of these lncRNAs were further examined via KEGG and GO analysis using DAVID online software. Finally, the relationship between these lncRNAs and immune cell infiltration in tumors and their effect on immune checkpoint inhibitors were further explored., Results: We identified lncRNAs correlated with tumor cell immune evasion in sarcoma. The expression of these lncRNAs was upregulated and correlated with worse prognosis in sarcoma and other human cancer types. Moreover, low DNA methylation occupation of these lncRNA loci was detected. Negative correlations between DNA methylation and lncRNA expression were also found in sarcoma and other human cancer types. KEGG and GO analyses indicated that these lncRNAs correlated with immune evasion and negative regulation of the immune response in sarcoma. Finally, high expression of these lncRNAs correlated with more suppressive immune cell infiltration and reduced sensitivity to immune checkpoint inhibitors in sarcoma and other human cancer types., Conclusion: Our results suggest that long noncoding RNAs confer immune checkpoint inhibitor resistance in human cancer. Further characterization of these lncRNAs may help to elucidate the mechanisms underlying immune checkpoint inhibitor resistance and uncover a novel therapeutic intervention point for immunotherapy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Pang and Hao.)

Background: With the development of medical technology, credible options for defect reconstructions after the resection of benign bone tumors of the lower extremities have become a high priority. As the current reconstructive methods commonly used in clinical practice have some flaws, new methods of reconstruction need to be explored. We aimed to prepare a new kind of bioactive scaffold for the repair of bone defects through a stem cell rapid screening-enrichment-composite technology system developed by our team. Furthermore, we aimed to investigate the curative effects of these bioactive scaffolds., Methods: Firstly, cell count, trypan blue exclusion rate, and ALP staining were used to evaluate changes in enrichment efficiency, cell activity, and osteogenic ability before and after enrichment. Then, the scaffolds were placed under the skin of nude mice to verify their osteogenic effects in vivo. Finally, the scaffolds were used for the reconstruction of bone defects after operations for benign bone tumors in a patient's lower limb. The healing status of the defect site at 1 and 3 months was assessed by X-ray, and the Musculoskeletal Tumor Society (MSTS) score was applied to reflect the recovery of patient limb function., Results: The system effectively enriched stem cells without affecting the activity and osteogenic abilities of the bone marrow mesenchymal stem cells (BMSCs). Meanwhile, the bioactive scaffolds obtained better osteogenic effects. In patients, the active scaffolds showed better bone integration and healing status, and the patients also obtained higher MSTS scores at 1 and 3 months after surgery., Conclusion: As a new technique, the rapid screening-enrichment-composite technology of stem cells demonstrates a better therapeutic effect in the reconstruction of bone defects after surgery for benign bone tumors of the lower extremities, which will further improve patient prognosis.

Limb salvage surgery of malignant pelvic tumors is the most challenging procedure in musculoskeletal oncology due to the complex anatomy of the pelvic bones and soft tissues. It is crucial to accurately resect the pelvic tumors with appropriate margins in this procedure. However, there is still a lack of efficient and repetitive image planning methods for tumor identification and segmentation in many hospitals. In this paper, we present a novel deep learning-based method to accurately segment pelvic bone tumors in MRI. Our method uses a multi-view fusion network to extract pseudo-3D information from two scans in different directions and improves the feature representation by learning a relational context. In this way, it can fully utilize spatial information in thick MRI scans and reduce over-fitting when learning from a small dataset. Our proposed method was evaluated on two independent datasets collected from 90 and 15 patients, respectively. The segmentation accuracy of our method was superior to several comparing methods and comparable to the expert annotation, while the average time consumed decreased about 100 times from 1820.3 seconds to 19.2 seconds. In addition, we incorporate our method into an efficient workflow to improve the surgical planning process. Our workflow took only 15 minutes to complete surgical planning in a phantom study, which is a dramatic acceleration compared with the 2-day time span in a traditional workflow., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: /Objective: This study aimed to evaluate the effectiveness and safety of treating medial malleolar fractures using our patented Mg-Nd-Zn-Zr alloy (abbr. JDBM) screws with Ca-P coating, in order to provide a solid basis for their further clinical translation., Methods: Nine patients with medial malleolar fractures were treated using coated JDBM screws. All patients had closed injuries, and none had open fractures. Postoperative radiography was performed to evaluate fracture healing and degradation of the JDBM screws. The visual analogue scale (VAS) was used to evaluate the degree of postoperative pain perceived by the patients, and the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot scoring system was used to evaluate their postoperative ankle function. Postoperative complications, including infection, failure of internal fixation, and malunion, were carefully recorded during follow-up., Results: The mean follow-up time was 12.2 ​± ​4.9 months. After the operation, all patients achieved good medial malleolar fracture alignment, and none of them experienced breakage of the JDBM screws before fracture healing. Postoperative radiography indicated JDBM screws gradually degradated with implantation time, and obvious degradation could be observed 12 months, postoperatively. At the final follow-up, the patients' mean VAS score was 2.3 ​± ​1.9. The mean AOFAS score was 90.4 ​± ​8.9, with excellent or good rates of 88.9%. None of the patients experienced infection, failure of internal fixation, malunion, or other complications., Conclusion: Coated biodegradable JDBM screws are effective for the treatment of medial malleolar fractures, and have good prospects for further clinical translation in the future., Translational Potential Statement: The results of this study indicates coated biodegradable JDBM screw is an alternative internal fixation instrument for fracture treatment and has excellent prospects for clinical translation., Competing Interests: The authors have no conflicts of interest relevant to this article., (© 2020 The Authors.)

Hypoxia has been firmly correlated to the drug resistance of solid tumors. Alleviation of hypoxia by tumor reoxygenation is expected to sensitize the chemotherapy toward solid tumors. Alternatively, ferroptosis provides a therapeutic strategy to overcome apoptotic resistance and multidrug resistance of solid tumors, collaboratively strengthening the chemotherapy toward hypoxic tumors. Herein, an ultrasound (US)-activatable nanomedicine was developed for overcoming hypoxia-induced resistance to chemotherapy and efficiently inhibiting tumor growth by inducing sensitized apoptosis and collaborative ferroptosis of tumor cells. This nanomedicine was constructed by integrating ferrate and doxorubicin into biocompatible hollow mesoporous silica nanoplatforms, followed by assembling a solid-liquid phase-change material of n-heneicosane. The US-induced mild hyperthermia initiates the phase change of n-heneicosane, enabling US-activated co-release of ferrate and doxorubicin. Results reveal that the released ferrate effectively reacts with water as well as the over-expressed hydrogen peroxide and glutathione in tumor cells, achieving tumor-microenvironment-independent reoxygenation and glutathione-depletion in tumors. The reoxygenation down-regulates expressions of hypoxia-inducible factor 1α and multidrug resistance gene/transporter P-glycoprotein in tumor cells, sensitizing the apoptosis-based doxorubicin chemotherapy. More importantly, exogenous iron metabolism from the nanomedicine initiates intracellular Fenton reactions, leading to reactive oxygen species overproduction and iron-dependent ferroptotic death of tumor cells. Furthermore, the glutathione-depletion inactivates the glutathione peroxidase 4 (GPX4, a critical regulatory target in ferroptosis), inhibiting the reduction of lipid peroxides and reinforcing the ferroptotic cell death. The sensitized chemotherapy together with the iron-dependent ferroptosis of tumor cells play a synergistic role in boosting the growth suppression of hypoxic osteosarcoma in vivo. Additionally, the nanomedicine acts as a nanoprobe for in vivo photoacoustic imaging and glutathione tracking, showing great potential as theranostic agents for hypoxic solid tumors treatment., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Despite significant advances in osteochondral tissue engineering, it remains challenging to successfully reconstruct native-like complex tissues organized in three-dimension with spatially varying compositional, structural and functional properties. In this contribution, inspired by the gradients in extracellular matrix (ECM) composition and collagen fiber architecture in native osteochondral tissue, we designed and fabricated a tri-layered (superficial cartilage (S), deep cartilage (D) and subchondral bone (B) layer) stratified scaffold in which a mesenchymal stem cell (MSC)-laden gelatin methacrylamide (GelMA) hydrogel with zone-specific growth factor delivery was combined with melt electrowritten triblock polymer of poly(ε-caprolactone) and poly(ethylene glycol) (PCEC) networks with depth-dependent fiber organization. Introducing PCEC fibers into the weak GelMA hydrogel contributed to a significant increase in mechanical strength. In vitro biological experiments indicated that the stratified fiber-reinforced and growth factor-loaded hydrogel construct induced the MSCs to differentiate down both the chondrogenic and osteogenic lineages and that the engineered complex exhibited cellular phenotype and matrix accumulation profiles resembling those of the native tissue. Simultaneous cartilage and subchondral bone regeneration were achieved in vivo by using the tri-layered integrated scaffold. More importantly, the inclusion of the S layer could impart the regenerated cartilage with a more lubricating and wear-resistant surface. These findings suggest that the bioinspired construct mimicking the spatial variations of native osteochondral tissue might serve as a promising candidate to enhance osteochondral regeneration., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Breast cancer (BC) is the most common malignant disease affecting women's health worldwide. The benefits from conventional therapeutic modalities are severely limited. An increasing number of promising photothermal materials have been recently developed and introduced into the therapeutic regimens of BC, but the underlying biological mechanism remains unclear. Silicon-based materials have enjoyed many popularities in the biomedical field owing to their desirable biocompatibility, biodegradability and versatility. Herein, we introduced two dimensional (2D) silicene nanosheets (SNSs) into the BC treatment and achieved profound photothermal-ablation efficacy. Importantly, this work reveals the underlying biological mechanism and regulation factors of photonic hyperthermia in BC. The RNA sequencing and immunoblot demonstrated that photothermia enhanced apoptosis in BC by activating caspase 3 and caspase 7. Importantly, knockdown of lysine demethylase KDM3A sensitized BC to photothermia epigenetically. It has been revealed that KDM3A could erase p53K372me1 and suppress the anti-cancer functions of p53, leading to the downregulation of pro-apoptotic proteins-PUMA and NOXA verified by Co-IP and ChIP-qPCR assays. Therefore, our results not only import near infrared light (NIR) induced photothermal ablation generated by SNSs-BSA into the BC treatment, but also clarify the underlying mechanism and regulation factors for further photothermal performance optimization and clinical translation., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Polycaprolactone (PCL) is widely used in bone tissue engineering due to its biocompatibility and mechanical strength. However, PCL is not biologically active and shows poor hydrophilicity, making it difficult for new bones to bind tightly to its surface. Magnesium (Mg), an important component of natural bone, exhibits good osteo-inductivity and biological activity. Therefore, porous PCL/Mg scaffolds, including pure PCL, PCL/5%Mg, PCL/10%Mg, and PCL/15%Mg, were prepared to elucidate whether the porous structure of scaffolds and the bioactivity of PCL may be enhanced via 3D printing and incorporation of Mg powder. Compared with the control group (pure PCL only), the hydrophilicity of composite PCL/Mg scaffolds was greatly increased, resulting in the scaffolds having decreased water contact angles. Tests for adhesion and proliferation of rat bone marrow mesenchymal stem cells (rBMSCs) indicated that the PCL/10%Mg scaffold showed superior compatibility. Furthermore, as indicated by alkaline phosphatase (ALP) activity and semiquantitative analysis of alizarin red staining, PCL/10%Mg scaffolds exhibited significantly stronger osteogenic activity than the other scaffolds. Animal experiments demonstrated that PCL/10%Mg scaffolds displayed pro-osteogenic effects at an early stage (4 weeks) and produced more new bone mass 8-12 weeks following implantation, compared with the control group. Visceral and blood parameter analyses indicated that PCL/10%Mg scaffolds did not exert any noticeable toxic effects. PCL/10%Mg composite scaffolds were found to promote bone defect repair at an early stage with good cytocompatibility. This finding revealed a new concept in designing bone tissue materials, which showed potential as a clinical treatment for bone defects.

Hypoxemia after acute myocardial infarction (AMI) causes severe damage to cardiac cells and induces cardiac dysfunction. Protection of cardiac cells and reconstruction of cardiac functions by re-introducing oxygen into the infarcted myocardium represents an efficient approach for the treatment of AMI. However, the established methods for oxygen supplementation mainly focus on systemic oxygen delivery, which always results in inevitable oxidative stress on normal tissues. In this work, an ultrasound (US) activated oxygen generation nanosystem has been developed, which specifically releases oxygen in the infarcted myocardium and alleviates the hypoxemic myocardial microenvironment to protect cardiac cells after AMI. The nanosystem was constructed through the formation of calcium peroxide in the mesopores of biocompatible mesoporous silica nanoplatforms, followed by the assembly of the thermosensitive material heneicosane and polyethyleneglycol. The mild hyperthermia induced by US irradiation triggered the phase change of heneicosane, thus achieving US responsive diffusion of water and release of oxygen. The US-activated oxygen release significantly alleviated the hypoxia and facilitated the mitigation of oxidative stress after AMI. Consequently, the survival of cardiac cells under hypoxic conditions was substantially improved and the damage in the infarcted myocardial tissue was minimized. This US-activated oxygen generation nanosystem may provide an efficient modality for the treatment of AMI.

There is a large gap between the elastic modulus of the existing femoral stem and the host bone. This gap can lead to long-term complications, such as aseptic loosening and, eventually, a need for revision surgery. The porous metallic biomimetic femoral stem can effectively reduce stress shielding and provide firm implant fixation through bone ingrowth. The purpose of this research is to investigate the application of different porous femoral stems in relieving bone resorption and promoting osseointegration by finite element analysis. We present an intuitive visualization method based on a diamond lattice structure to understand the relationship between pore size, porosity, bone ingrowth criteria and additive manufacturing constraints. We further obtain an admissible design space of diamond lattice structure for porosity selection. We evaluate the relative micromotion of bone-implant interface and bone volume with density loss for three femoral stems with diamond lattice-based homogenous porous structures in admissible design space. We also evaluate porous femoral stems with four different grading orientations along the axial and radial directions of the femoral stem. These include an axial graded femoral stem with a porosity increased distally (DAGS), an axial graded femoral stem with a porosity increased proximally (PAGS), a radial graded femoral stem with a porosity increased inwardly (IRGS), and a radial graded femoral stem with a porosity increased externally (ERGS). The results indicate that: (i) homogenous porous femoral stems with 40% porosity, (ii) DAGS and (iii) IRGS can maintain the relative micromotion of the bone-implant interface in the safety range for bone ingrowth. The calculated volumes of bone with density loss in the cases of DAGS and IRGS are 3.6% and 3.3%, respectively, which are nearly 74% lower than that of fully dense stems. Therefore, DAGS and IRGS have an evident advantage in promoting osseointegration and relieving bone resorption. Thus, the graded femoral stem is more promising than the homogeneous porous stem., (Copyright © 2020 IPEM. Published by Elsevier Ltd. All rights reserved.)

Recently, more interest has been paid to the association between bone mass and gut microecological dysbiosis. The results of clinical studies comparing gut microbiota (GM) in osteoporosis patients have been inconsistent due to different inclusion and exclusion criteria. To date, the association between the GM and senile osteoporosis remains poorly understood. Here, we utilized an aged rat model (22 months old) of senile osteoporosis to study the association of the composition and function of the GM with osteoporosis by 16S rRNA and metagenomic sequencing. The results showed that there was a significant reduction in alpha diversity and the F/B ( Firmicutes/Bacteroidetes ) ratio in aged rats. At the genus level, the enrichment of Helicobacter was potentially related to osteoporosis as a risk factor. Metagenomics results based on two databases indicated that shifts in the GM contribute to senile osteoporosis through metabolic pathways and subsequent immune disorders. In conclusion, our study reveals the association of gut microbiota composition and function with senile osteoporosis in an aged rat model in a brand new way, and variations in the GM might contribute to senile osteoporosis through metabolic pathways.

As a critical factor involved in the maintenance of physiological homeostasis, the gut microbiota (GM) reportedly plays a key role in bone development. To date, the association between the GM and steroid deficiency-induced osteoporosis remains poorly understood. Forty female Sprague Dawley rats were divided into an ovariectomy (OVX) or control group. We performed 16S rRNA and metagenome sequencing, to compare diversity, taxonomic differences, and functional genes. The GM composition did not change in the control group and the number of operational taxonomic units increased significantly following ovariectomy. Alpha diversity, determined by ACE estimator, CHAO estimator, the Shannon index, and the Simpson index showed an increasing trend after ovariectomy. Samples in the OVX group were well clustered both pre- and post-ovariectomy, as demonstrated by principal coordinate 1 (PC1) and PC2. Functional genes of GM, including those involved in synthesis and metabolism of carbohydrates and nucleotides, microbial structure, and heme, as well as hemin uptake and utilization, increased at the early stage of osteoporosis. We observed that Ruminococcus flavefaciens exhibited the greatest variation in abundance among the GM and this was also associated with osteoclastic indicators and the estrobolome. Specific changes in fecal microbiota are associated with the pathogenesis of steroid deficiency-induced osteoporosis.

Background: Bone scaffold is one of the most effective methods to treat bone defect. The ideal scaffold of bone tissue should not only provide space for bone tissue growth, but also have sufficient mechanical strength to support the bone defect area. Moreover, the scaffold should provide a customized size or shape for the patient's bone defect., Methods: In this study, strontium-containing Mg-doped wollastonite (Sr-CSM) bioceramic scaffolds with controllable pore size and pore structure were manufactured by direct ink writing 3D printing. Biological properties of Sr-CSM scaffolds were evaluated by apatite formation ability, in vitro proliferation ability of rabbit bone-marrow stem cells (rBMSCs), and alkaline phosphatase (ALP) activity using β-TCP and Mg-doped wollastonite (CSM) scaffolds as control. The compression strength of three scaffold specimens was probed after completely drying them while been submerged in Tris-HCl solution for 0, 2,4 and 6 weeks., Results: The mechanical test results showed that strontium-containing Mg-doped wollastonite (Sr-CSM) scaffolds had acceptable initial compression strength (56 MPa) and maintained good mechanical stability during degradation in vitro. Biological experiments showed that Sr-CSM scaffolds had a better apatite formation ability. Cell experiments showed that Sr-CSM scaffold had a higher cell proliferation ability compared with β-TCP and CSM scaffold. The higher ALP activity of Sr-CSM scaffold indicates that it can better stimulate osteoblastic differentiation and bone mineralization., Conclusions: Therefore, Sr-CSM scaffolds not only have acceptable compression strength, but also have higher osteogenesis bioactivity, which can be used in bone tissue engineering scaffolds.

Titanium-tantalum-niobium-zirconium (Ti-Ta-Nb-Zr) alloy is a novel material currently available for orthopedic applications. However, these scaffolds, manufactured using traditional methods, present disadvantages such as irregular pore size, unsuitable mechanical features, and poor connectivity between pores. In this study, porous Ti-Ta-Nb-Zr (60% Ti, 2% Ta, 36% Nb, and 2% Zr) scaffolds were printed by selective laser melting (SLM) with a controllable pore size of 300-400 μm. The mechanical properties of the SLM-manufactured scaffolds were evaluated, as well as its osteogenesis in vitro and osteointegration in vivo. Porous Ti-Ta-Nb-Zr scaffolds yielded superior cell proliferation and cell adhesion results with human bone mesenchymal stem cells (hBMSCs) compared with porous Ti6Al4V scaffolds. The osteogenic differentiation experiment demonstrated enhanced osteogenic differentiation of hBMSCs in the Ti-Ta-Nb-Zr group than in the Ti6Al4V group. After the porous Ti-Ta-Nb-Zr or control scaffolds were implanted into a cylindrical bone defect in the rabbit lateral femoral condyle, the initial radiological results confirmed the excellent osteogenic activity of the novel 3D-printed scaffolds. Histological analysis further indicated that the Ti-Ta-Nb-Zr scaffolds promoted bone regeneration and osteointegration more effectively than Ti6Al4V scaffolds. Our findings demonstrate that the SLM-manufactured porous Ti-Ta-Nb-Zr scaffold has considerable potential for clinical orthopedic application.

Background: This study aimed to evaluate the validity of proximal fibular anatomic landmarks for measuring the coronal tibial mechanical axis in patients with knee osteoarthritis and to investigate individual factors associated with their reliability., Methods: A total of 106 knees in 96 patients were retrospectively reviewed. The angles between the tibial mechanical axis and fibular shaft axis (TFA), medial cortex of the proximal fibular shaft (MTA), and lateral cortex of the proximal fibular shaft (LTA) were measured from full-leg standing digital anteroposterior radiographs. An angle within three degrees was considered reliable. The association between the above three angles and individual factors, such as age, sex, body mass index (BMI), and varus-valgus knee malalignment, was determined to investigate individual factors associated with their reliability., Results: The median TFA, MTA, and LTA were 1.52°, 1.56°, and 2.62°, respectively. The reliability rates of TFA, MTA, and LTA were 73.6% (95% CI: 65.19-81.98%), 82.1% (74.77-89.38%), and 58.5% (49.11-67.87%), respectively. The reliability of TFA and MTA was not associated with individual variables. The reliability of LTA was associated with BMI. Among patients with BMI greater than 25.3 kg/m 2 , LTA was considered reliable in 65.7%; this rate was significantly higher than that among patients with BMI less than 25.3 kg/m 2 ., Conclusions: The fibular shaft axis and medial cortex of the proximal fibular shaft are reliable landmarks of the mechanical axis of the tibia. However, the reliability of the lateral cortex of the proximal fibular shaft is less satisfactory, especially in patients with BMI less than 25.3 kg/m 2 ., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: A porous Ti6Al4V implant that is manufactured using selective laser melting (SLM) has broad potential applications in the field of orthopaedic implants. The pore structure of the SLM porous Ti6Al4V implant allows for cell migration and osteogenic differentiation, which is favorable for bone ingrowth and osseointegration. However, it is unclear whether the pore structure and partially melted Ti6Al4V particles on a SLM porous Ti6Al4V implant will increase bacterial adhesion and, perhaps, the risk of implant-related infection., Questions/purposes: (1) Is there more bacterial adhesion and colonization on SLM porous Ti6Al4V implants than on polished orthopaedic implants? (2) Do partially melted Ti6Al4V particles on SLM porous Ti6Al4V implants reduce human bone mesenchymal stem cells (hBMSCs) adhesion, viability, and activity?, Methods: To determine bacterial adhesion and biofilm formation, we incubated five different Ti6Al4V discs (polished, grit-blasted, plasma-sprayed, particle SLM porous, and nonparticle SLM porous discs) with methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli. Bacterial coverage on the surface of the five different Ti6Al4V discs were evaluated based on scanning electron microscopy (SEM) images quantitatively. In addition, a spread-plate method was used to quantitatively evaluate the bacterial adhesion on those implants. The biofilm formation was stained with crystal violet and semi-quantitatively determined with a microplate reader. The morphology and adhesion of hBMSCs on the five Ti6Al4V discs were observed with SEM. The cell viability was quantitatively evaluated with a Cell Counting Kit-8 assay. In addition, the osteogenic activity was determined in vitro with a quantitatively alkaline phosphatase activity assay and alizarin-red staining. For semiquantitative analysis, the alizarin-red stained mineralized nodules were dissolved and determined with a microplate reader., Results: The polished discs had the lowest MRSA adhesion (8.3% ± 2.6%) compared with grit-blasted (19.1% ± 3.9%; p = 0.006), plasma-sprayed (38.5% ± 5.3%; p < 0.001), particle (23.1% ± 2.8%; p < 0.001), and nonparticle discs (15.7% ± 2.5%; p = 0.003). Additionally, when comparing the two SLM discs, we found that particle discs had higher bacterial coverage than nonparticle discs (23.1% ± 2.8% versus 15.7% ± 2.5%; p = 0.020). An E. coli analysis showed similar results, with the higher adhesion to particle SLM discs than to nonparticle discs (20.7% ± 4.2% versus 14.4% ± 3.6%; p = 0.011). In addition, on particle SLM porous discs, bacterial colonies were localized around the partially melted Ti6Al4V particles, based on SEM images. After a 7-day incubation period, the cell viability in the particle group (optical density value 0.72 ± 0.05) was lower than that in the nonparticle groups (optical density value: 0.87 ± 0.08; p = 0.003). Alkaline phosphatase activity, as a marker of osteogenic differentiation, was lower in the particle group than in the nonparticle group (1.32 ± 0.12 U/mL versus 1.58 ± 0.09 U/mL; p = 0.012)., Conclusion: Higher bacterial adhesion was observed on SLM porous discs than on polished discs. The partially melted Ti6Al4V particles on SLM porous discs not only enhanced bacterial adhesion but also inhibited the osteogenic activity of hBMSCs. Postprocessing treatment is necessary to remove partially melted Ti6Al4V particles on an SLM implant before further use. Additional studies are needed to determine whether an SLM porous Ti6Al4V implant increases the risk of implant-related infection in vivo., Clinical Relevance: As implants with porous Ti6Al4V made using SLM are being designed, our preliminary findings suggest that postprocessing treatment is needed to remove partially melted Ti6Al4V particles before further use. In addition, the depth of the porous structure of the SLM implant should not exceed the maximum depth of bone ingrowth because the host immune defense cannot prevent bacterial adhesion without integration.

The porous surface of a polyetheretherketone (PK)-nanoporous lithium-doped magnesium silicate (NLS) blend (PKNLS) was fabricated on a PK surface by layer-by-layer pressuring, sintering, and salt-leaching. As controls, porous surfaces of a PK/lithium-doped magnesium silicate blend (PKLS) and PK were fabricated using the same method. The results revealed that porosity, water absorption, and protein absorption of the porous surface of PKNLS containing macropores and nanopores were obviously enhanced compared to PKLS and PK containing macropores without nanopores. In addition, PKNLS, with both macroporostiy and nanoporosity, displayed the highest ability of apatite mineralization in simulated body liquid, indicating excellent bioactivity. In vitro responses (including adhesion, proliferation, and differentiation) of MC3T3E1 cells to PKNLS were significantly enhanced compared to PKLS and PK. In vivo implantation results showed that new bone grew into the macroporous surface of PKNLS, and the amount of new bone for PKNLS was the highest. In short, PKNLS integration with PK significantly promoted cells/bone-tissue responses and exhibited excellent osteogenesis in vivo, which might have great potential for bone repair., Competing Interests: The authors report no conflicts of interest in this work.

Trace elements play important roles in human health, but little is known about their functions in humoral immunity. Here, we show an important role for iron in inducing cyclin E and B cell proliferation. We find that iron-deficient individuals exhibit a significantly reduced antibody response to the measles vaccine when compared to iron-normal controls. Mice with iron deficiency also exhibit attenuated T-dependent or T-independent antigen-specific antibody responses. We show that iron is essential for B cell proliferation; both iron deficiency and α-ketoglutarate inhibition could suppress cyclin E1 induction and S phase entry of B cells upon activation. Finally, we demonstrate that three demethylases, KDM2B, KDM3B and KDM4C, are responsible for histone 3 lysine 9 (H3K9) demethylation at the cyclin E1 promoter, cyclin E1 induction and B cell proliferation. Thus, our data reveal a crucial role of H3K9 demethylation in B cell proliferation, and the importance of iron in humoral immunity.

Background/aim: Osteosarcoma (OS) is a diagnosed primary cancer of the bone. Despite the great advances that have been made during the past decades in OS therapy, drug resistance and tumor recurrence are still major problems. It is urgent to find novel strategies to overcome drug resistance in order to prolong the survival time of OS patients., Materials and Methods: Cell viability was investigated by the cell count kit-8 (CCK-8) and colony formation assays. P-Glycoprotein (P-gp) expression was analyzed by RT-qPCR and western blot. A xenograft mouse model was used to identify the synergistic efficacy of a P-gp inhibitor with cisplatin. Student's t-test was used to determine statistically significant differences., Results: P-gp expression levels were associated with cisplatin efficacy in OS patients. OS cells with higher P-gp expression were more resistant to cisplatin. Knockdown or inhibition of P-gp sensitized OS cells to cisplatin., Conclusion: Down-regulating the expression of P-gp in OS maybe a promising strategy to overcome cisplatin resistance., (Copyright© 2019, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Antibacterial and osteogenic design is required for ideal orthopedic implants. The excellent antimicrobial performance of silver nanoparticles (AgNPs) has attracted interest for the treatment of implant-related infections. However, the dose-dependent cytotoxicity of silver and its negative impact on bone implants restrict the further use of AgNPs coatings. Therefore, a hybrid coating containing polydopamine (PDA), hydroxyapatite (HA), AgNPs, and chitosan (CS) is prepared. Organic chelators CS and PDA that have promising biocompatibility are used to prevent the rapid release of silver ions from the AgNPs coating. The double chelating effect of PDA and CS significantly reduces silver ion release from the hybrid coating. The coating exhibits excellent anti-biofilm efficiency of 91.7%, 89.5%, and 92.0% for Staphylococcus aureus, Staphylococcus epidermidis, and Escherichia coli, respectively. In addition, the coating can significantly stimulate osteogenic differentiation of MC3T3-E1 cells and promote bone-implant osseointegration in vivo as compared to that in the control group. The longitudinal biosafety of the coating is confirmed in vivo by histological evaluation and blood tests. The results of this study indicate that the hybrid coating exhibits antibacterial properties as well as allow bone-implant osseointegration, thereby providing insight into the design of multifunctional implants for long-term orthopedic applications., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Porous tantalum (Ta) scaffold is a novel implant material widely used in orthopedics including joint surgery, spinal surgery, bone tumor surgery, and trauma surgery. However, porous Ta scaffolds manufactured using the traditional method have many disadvantages. We used selective laser melting (SLM) technology to manufacture porous Ta scaffolds, and the pore size was controlled to 400 μm. The compressive strength and elastic modulus of the porous scaffolds were evaluated in vitro. To evaluate the osteogenesis and osseointegration of Ta scaffolds manufactured by SLM technology, cytocompatibility in vitro and osseointegration ability in vivo were evaluated. This porous Ta scaffold group showed superior cell adhesion and proliferation results of human bone mesenchymal stem cells (hBMSCs) compared with the control porous Ti6Al4V group. Moreover, the alkaline phosphatase (ALP) activity at day 7 and the semiquantitative analysis of Alizarin red staining at day 21 demonstrated that osteogenic differentiation of hBMSCs was enhanced in the Ta group. The porous Ta scaffold was implanted into a cylindrical bone defect with a height and diameter of 1 and 0.5 cm, respectively, in the lateral femoral condyle of New Zealand rabbits. Radiographic analysis showed that the new bone formation in Ta scaffolds was higher than that in Ti6Al4V scaffolds. Histological images indicated that compared with porous Ti6Al4V scaffolds, Ta scaffolds increased bone ingrowth and osseointegration. The porous Ta scaffold manufactured by SLM not only has a regular pore shape and connectivity but also has controllable elastic modulus and compressive strength. Moreover, the osteogenesis and osseointegration results in vitro and in vivo were improved compared with those of the porous Ti6Al4V scaffold manufactured using the same technology. These findings demonstrate that the porous Ta scaffold manufactured by SLM is potentially useful for orthopedic clinical application.

Osteosarcoma (OS) is a primary malignant bone tumour. However, the genetic basis for the pathogenesis of OS remains elusive. In this study, we uncovered the role of the histone methyltransferase NSD2 in regulating tumourigenesis and chemosensitivity in OS. We show that NSD2 knockdown leads to increased apoptosis in OS cells in vitro and in vivo. Additionally, NSD2 knockdown significantly enhances the efficacy of cisplatin against OS cells and accordingly inhibits properties associated with cancer stem cells (CSCs). Furthermore, RNA sequencing (RNAseq) and Gene Ontology (GO) analysis revealed that NSD2 promotes transcription of genes associated with negative regulation of apoptotic signalling pathways and CSC properties. The results of chromatin immunoprecipitation quantitative polymerase chain reaction (ChIP-qPCR) assays indicated that NSD2 knockdown leads to decreased H3K36me2 modification at BCL2 and SOX2 loci, thus inhibiting the transcription of these two genes that are closely correlated with apoptosis, CSC properties and chemosensitivity in OS cells. Pathway analysis demonstrated that the ERK and AKT pathways mediate the regulation of OS progression and chemosensitivity by NSD2. Overall, our study is the first to uncover the function of NSD2 in OS chemosensitivity. NSD2 regulates the expression of the apoptosis regulatory proteins BCL2 and SOX2 through the ERK and AKT pathways. Our results suggest that NSD2 is a new target for combined chemotherapy and is a prognostic factor for OS.

Background: In osteosarcoma (OS), chemotherapy resistance has become one of the greatest issues leading to high mortality among patients. However, the mechanisms of drug resistance remain elusive, limiting therapeutic efficacy. Here, we set out to explore the relationship between dynamic histone changes and the efficacy of cisplatin against OS., Results: First, we found two histone demethylases associated with histone H3 lysine 27 trimethylation (H3K27me3) demethylation, KDM6A, and KDM6B that were upregulated after cisplatin treatment. Consistent with the clinical data, cisplatin-resistant OS specimens showed lower H3K27me3 levels than sensitive specimens. Then, we evaluated the effects of H3K27me3 alteration on OS chemosensitivity. In vitro inhibition of the histone methyltransferase EZH2 in OS cells decreased H3K27me3 levels and led to cisplatin resistance. Conversely, inhibition of the demethylases KDM6A and KDM6B increased H3K27me3 levels in OS and reversed cisplatin resistance in vitro and in vivo. Mechanistically, with the help of RNA sequencing (RNAseq), we found that PRKCA and MCL1 directly participated in the process by altering H3K27me3 on their gene loci, ultimately inactivating RAF/ERK/MAPK cascades and decreasing phosphorylation of BCL2., Conclusions: Our study reveals a new epigenetic mechanism of OS resistance and indicates that elevated H3K27me3 levels can sensitize OS to cisplatin, suggesting a promising new strategy for the treatment of OS.

Although anlotinib, a multi-targeted receptor tyrosine kinase inhibitor has been reported have antitumor effects in many preclinical and clinical trials, little is known about its effect on hepatocellular carcinoma (HCC). Here, we have shown the antitumor effects of anlotinib on HCC. Data indicated that anlotinib application significantly inhibited HCC cell viability, proliferation, colony formation, and prompted apoptosis in vitro. Furthermore, animal experiments also illustrated that anlotinib alleviated HCC progression. Mechanically, we demonstrated that anlotinib treatment downregulated the anti-apoptotic protein Bcl-2 and Survivin, but upregulated pro-apoptotic molecule Bax, which accounts for its therapeutic effect on HCC. Pathway analysis has shown decreased phosphorylation levels of Erk and Akt. Together, this study suggests that anlotinib may have a direct antitumor progression effect on HCC by inhibiting Bcl-2 and Survivin expression, promoting Bax expression via inactivating Erk and Akt pathways and could be a promising agent treating HCC., (Copyright © 2018 Elsevier Inc. All rights reserved.)

In this work, the in vivo biocompatibility and biodegradation behavior of Mg-Nd-Zn-Zr alloy (denoted as JDBM) screws were studied using a goat femoral condyle fracture model. Blood analysis indicates that the liver and kidney functions of goats were not affected by JDBM, JDBM coated with brushite (denoted as JDBM-DCPD) and PLA implants. Radiographic analysis shows that JDBM-DCPD screw has lower degradation rate than JDBM. Histological images show that compared with PLA, JDBM and JDBM-DCPD show superior effect to promote more new bone formation. JDBM-DCPD group has more new bone formation than JDBM group, indicating good osteoinductivity of DCPD coating. JDBM group show higher osteogenic factors level (BMP2, ALP and OC) in peri-implant callus tissue than PLA group. Long-term (18months) in vivo implants Micro-CT result shows that the degradation of JDBM-DCPD screw may be slower than desirable, and the thickness of DCPD coating could be further adjusted to match the degradation to the bone recovery., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Prosthetic reconstruction may be a promising treatment for peri-acetabular malignant bone tumour; however, it is associated with a high complication rate. Therefore, prosthetic design and approach of prosthetic reconstruction after tumour resection warrant study., Methods: We retrospectively analyzed 11 patients with peri-acetabular malignant bone tumours treated by personalized 3D-printed hemipelvic prostheses after en bloc resection between 2015 and 2016. Pre-operative and post-operative pain at rest was assessed according to a 10-cm VAS score. The results of functional improvement were evaluated using the MSTS-93 score at the final follow-up. We also analyzed tumour recurrence, metastases, and complications associated with the reconstruction procedure., Results: All patients were observed for six to 24 months with an average follow-up of 15.5 months. One patient had occasional pain of the involved hip at the final follow-up (VAS, pre vs. post 8 months: 3 vs. 2). The mean MSTS-93 score was 19.2 (range, 13-25). Hip dislocation was detected in two patients, while delayed wound healing occurred in one patient. One patient with mesenchymal chondrosarcoma had a left iliac bone metastasis. Local tumour recurrence was not observed., Conclusions: Reconstruction of bony defect after tumour resection using personalized 3D-printed hemipelvic prostheses can obtain acceptable functional results without severe complications. Based on previous reports and our results, we believe that reconstruction arthroplasty using 3D-printed hemipelvic prostheses will provide a promising alternative for those patients with peri-acetabular malignant bone tumours., Level of Evidence: Level IV, therapeutic study.

Osteoporotic fracture (OPF) remains a major clinical challenge for skeletal regeneration. Impaired osteogenesis and excessive remodeling result in prolonged and poor quality of fracture healing. To augment bone formation and inhibit excessive resorption simultaneously, we constructed a biodegradable magnesium-based implant integrated with the anti-catabolic drug zoledronic acid (ZA); this implant exhibits controllable, sustained release of magnesium degradation products and ZA in vitro. The extracts greatly stimulate the osteogenic differentiation of rat-bone marrow-derived mesenchymal stem cells (rBMSCs), while osteoclastogenesis is inhibited by ZA. Implantation of intramedullary nails to fix femur fracture in ovariectomy-induced osteoporotic rats for up to 12 weeks demonstrates magnesium implants alone can enhance OPF repair through promoting callus formation compared to conventional stainless steel, while the combinatory treatment with local ZA release from implant coating further increases bone regeneration rate and callus size, remarkably improves bone quality and mechanical strength and suppresses osteoclasts and bone remodeling, due to the synergistic effect of both agents. The slow and uniform degradation of the implant ensures a steady decrease in bending force, which meets clinical requirements. In summary, biodegradable magnesium-based implants can locally co-deliver magnesium degradation products and zoledronic acid in a controlled manner, and can be superior alternatives for the reconstruction of osteoporosis-related fracture., Statement of Significance: Management of osteoporotic fracture has posed a major challenge in orthopedics, as the imbalance between diminished osteogenesis and excessive bone remodeling often leads to delayed and compromised fracture repair. Among various efforts expended on augmenting osteoporotic fracture healing, herein we reported a new strategy by engineering and utilizing a biodegradable magnesium-based implant integrated with local drug delivery, specifically, zoledronic acid (ZA)-loaded polylactic acid/brushite bilayer coating on a biodegradable Mg-Nd-Zn-Zr alloy (denoted as Mg/ZA/CaP), aiming to combine the favorable properties of Mg and zoledronic acid for simultaneous modulation of bone formation and bone resorption. In vitro and in vivo studies demonstrated its superior treatment efficacy along with adequate degradation. It stimulated new bone formation while suppressing remodeling, ascribed to the local release of magnesium degradation products and zoledronic acid. To our knowledge, the enhanced fracture repair capability of Mg-based implants was for the first time demonstrated in an osteoporotic fracture animal model. This innovative biodegradable Mg-based orthopedic implant presents great potential as a superior alternative to current internal fixation devices for treating osteoporotic fracture., (Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)