Pelvic-girdle reconstruction with three-dimensional-printed endoprostheses after limb-salvage surgery for pelvic sarcomas: current landscape.

Resection of pelvic bone tumors and the subsequent reconstruction of the pelvic girdle pose challenges due to complex anatomy, load-bearing demands, and significant defects. 3D-printed implants have revolutionized pelvic girdle reconstruction by offering customized solutions, porous surface structures for precise resection with custom guides, and improved integration. Many tertiary medical centers have adopted 3Dprinted hemipelvic endoprostheses, leading to enhanced outcomes. However, most studies are limited to single centers, with a small number of cases and short follow-up periods. Additionally, the design of these implants often relies heavily on individual experience, resulting in a lack of uniformity and significant variation. To provide a comprehensive assessment of this technology, we conducted an analysis of existing literature, encompassing tumor resection classification, various types of prosthesis design, reconstruction concepts, and post-reconstruction functional outcomes.

Macrophage fusion event as one prerequisite for inorganic nanoparticle-induced antitumor response.

While most nanomaterials are designed to assist tumor therapy, some inorganic nanoparticles have been reported to impede cancer development. We assume that the immune response elicited by these foreign nanoparticles might be associated with the remodeling of immune landscape in the tumor microenvironment (TME). We studied representative inorganic nanoparticles widely used in the biomedical field and first demonstrated that needle-shaped hydroxyapatite (n-nHA), granule-shaped hydroxyapatite, and silicon dioxide can effectively impair tumor progression in vivo. Substantial multinucleated giant cells (MNGCs) were formed around these antitumor nanoparticles, while the ratio of monocytes and macrophages was decreased in the TME. We found that high expression of the STXBP6 protein induced by n-nHA-treated macrophages triggers autophagy, which markedly promotes macrophage fusion into MNGCs. In this way, extensive depletion of tumor-associated macrophages in the TME was achieved, which suppressed tumor growth and metastasis. This intrinsic antitumor immunity of inorganic nanoparticles should not be neglected when designing future nanomedicines to treat cancer.

Core-Shell Structured Porous Calcium Phosphate Bioceramic Spheres for Enhanced Bone Regeneration.

Adequate new bone regeneration in bone defects has always been a challenge as it requires excellent and efficient osteogenesis. Calcium phosphate (CaP) bioceramics, including hydroxyapatite (HA) and biphasic calcium phosphates (BCPs), have been extensively used in clinical bone defect filling due to their good osteoinductivity and biodegradability. Here, for the first time, we designed and fabricated two porous CaP bioceramic granules with core-shell structures, named in accordance with their composition as BCP@HA and HA@BCP (core@shell). The spherical shape and the porous structure of these granules were achieved by the calcium alginate gel molding technology combined with a H2O2 foaming process. These granules could be stacked to build a porous structure with a porosity of 65-70% and a micropore size distribution between 150 and 450 µm, which is reported to be good for new bone ingrowth. In vitro experiments confirmed that HA@BCP bioceramic granules could promote the proliferation and osteogenic ability when cocultured with bone marrow mesenchymal stem cells, while inhibiting the differentiation of RAW264.7 cells into osteoclasts. In vivo, 12 weeks of implantation in a critical-sized femoral bone defect animal model showed a higher bone volume fraction and bone mineral density in the HA@BCP group than in the BCP@HA or pure HA or BCP groups. From histological analysis, we discovered that the new bone tissue in the HA@BCP group was invading from the surface to the inside of the granules, and most of the bioceramic phase was replaced by the new bone. A higher degree of vascularization at the defect region repaired by HA@BCP was revealed by 3D microvascular perfusion angiography in terms of a higher vessel volume fraction. The current study demonstrated that the core-shell structured HA@BCP bioceramic granules could be a promising candidate for bone defect repair.