PI3K/Akt pathway-mediated enhancement of bone and vascular regeneration by gelatin/hyaluronic acid/exosome composite scaffold in bone tissue engineering

The Role of G Protein-Coupled Receptors in the Regulation of Orthopaedic Diseases by Gut Microbiota

Exercise and diet modulate the gut microbiota, which is involved in the regulation of orthopaedic diseases and synthesises a wide range of metabolites that modulate cellular function and play an important role in bone development, remodelling and disease. G protein-coupled receptors (GPCRs), the largest family of transmembrane receptors in the human body, interact with gut microbial metabolites to regulate relevant pathological processes. This paper provides a review of different dietary and exercise effects on the pathogenic gut microbiota and their metabolites associated with GPCRs in orthopaedic diseases. RESULTS: Generally, metabolites produced by gut microbiota contribute to the maintenance of bone health by activating the corresponding GPCRs, which are involved in bone metabolism, regulation of immune response, and maintenance of gut flora homeostasis. Exercise and diet can influence gut microbiota, and an imbalance in gut microbiota homeostasis can trigger a series of adverse immune and metabolic responses by affecting GPCR function, ultimately leading to the onset and progression of various orthopaedic diseases. Understanding these relationships is crucial for elucidating the pathogenesis of orthopaedic diseases and developing personalised probiotic-based therapeutic strategies. In the future, we should further explore how to prevent and treat orthopaedic diseases through GPCR-based modulation of gut microbes and their interactions. The development of substances that precisely modulate gut microbes through different exercises and diets will provide more effective interventions to improve bone health in patients.

3D-printed gallium-infused scaffolds for osteolysis intervention and bone regeneration

Exacerbation of osteolysis in osteoporotic bone defects presents a significant challenge for implant-based treatments. This underscores the urgent need to develop implants that actively mitigate osteolysis while simultaneously promoting bone regeneration. In this study, the osteogenic potential of mesoporous bioactive glass (MBG) and β-tricalcium phosphate (β-TCP) was combined with the anti-bone resorption property of Ga doping. Ga-MBG was synthesized using a self-transformation method and subsequently incorporated into β-TCP at concentrations of 5 wt%, 10 wt% and 15 wt%. Scaffolds were prepared using extrusion-based 3D printing. The cytocompatibility of the composite scaffolds and their regulatory effects on the differentiation of osteoblasts and osteoclasts were systematically examined. In addition, the molecular mechanisms underlying bone regeneration and osteolysis regulation in osteoblasts were explored. Subsequently, cranial defects were repaired in a rat model of osteoporosis to assess the therapeutic efficacy and biological safety of the optimal concentration of the Ga-MBG/TCP composite scaffold. These findings indicated that the 10 wt% Ga-MBG/TCP composite scaffold exhibited excellent biocompatibility, enhanced new bone formation, and effectively mitigated osteolysis. These results provide a foundation for further investigation into the optimal concentration of Ga-MBG implants and highlight their potential application in future therapies for osteoporotic bone defects.

Crafting the future of bone regeneration: the promise of supramolecular peptide nanofiber hydrogels

Bone tissue engineering has rapidly emerged as an ideal strategy to replace autologous bone grafts, establishing a comprehensive system centered on biomaterial scaffolds, seeding cells, bioactive factors, and biophysical stimulation, thus paving the way for new horizons in surgical bone regeneration. However, the scarcity of suitable materials poses a significant challenge in replicating the intricate multi-layered structure of natural bone tissue. Supramolecular peptide nanofiber hydrogels (SPNHs) have shown tremendous potential as novel biomaterials due to their excellent biocompatibility, biodegradability, tunable mechanical properties, and multifunctionality. Various supramolecular peptides can assemble into nanofiber hydrogels, while bioactive sequences and factors can be embedded through physical adsorption or covalent binding, endowing the hydrogels with diverse biochemical properties. Finally, this review explored the future challenges and prospects of SPNHs in bone tissue engineering, with the aim of providing insights for further advancements in this field.

Development of Biomimetic Substrates for Limbal Epithelial Stem Cells Using Collagen-Based Films, Hyaluronic Acid, Immortalized Cells, and Macromolecular Crowding

Despite the promising potential of cell-based therapies developed using tissue engineering techniques to treat a wide range of diseases, including limbal stem cell deficiency (LSCD), which leads to corneal blindness, their commercialization remains constrained. This is primarily attributable to the limited cell sources, the use of non-standardizable, unscalable, and unsustainable techniques, and the extended manufacturing processes required to produce transplantable tissue-like surrogates. Herein, we present the first demonstration of the potential of a novel approach combining collagen films (CF), hyaluronic acid (HA), human telomerase-immortalized limbal epithelial stem cells (T-LESCs), and macromolecular crowding (MMC) to develop innovative biomimetic substrates for limbal epithelial stem cells (LESCs). The initial step involved the fabrication and characterization of CF and CF enriched with HA (CF-HA). Subsequently, T-LESCs were seeded on CF, CF-HA, and tissue culture plastic (TCP). Thereafter, the effect of these matrices on basic cellular function and tissue-specific extracellular matrix (ECM) deposition with or without MMC was evaluated. The viability and metabolic activity of cells cultured on CF, CF-HA, and TCP were found to be similar, while CF-HA induced the highest (p < 0.05) cell proliferation. It is notable that CF and HA induced cell growth, whereas MMC increased (p < 0.05) the deposition of collagen IV, fibronectin, and laminin in the T-LESC culture. The data highlight the potential of, in particular, immortalized cells and MMC for the development of biomimetic cell culture substrates, which could be utilized in ocular surface reconstruction following further in vitro, in vivo, and clinical validation of the approach.