Bioceramics/Electrospun Polymeric Nanofibrous and Carbon Nanofibrous Scaffolds for Bone Tissue Engineering Applications

Lamb1-mediated Wnt/β-catenin signaling pathway drives endothelial angiogenesis for fracture healing

OBJECTIVES

Fractures, usually caused by trauma or osteoporosis, are the most common traumatic injuries to large organs in humans. Osteogenesis and angiogenesis are two crucial parts of fracture healing that work together to promote the repair and regeneration of damaged bone. Endothelial cell migration is critical for angiogenesis. Therefore, it is well worth exploring whether endothelial cells (ECs) can enhance fracture healing.

METHODS

The public datasets were analyzed by scRNA-seq, and the ECs were subjected to subset analysis and pseudotime analysis. Next, ECs_Lamb1+ cells underwent GO and KEGG pathway enrichment analyses, and were subjected to GSVA. Finally, the mechanism was verified and evaluated via qRT-PCR, cellular immunofluorescence staining, and transwell assay.

RESULTS

After cell annotations, 9 cell types were obtained, and it was found that the proportions of ECs were significantly reduced. EC subset analysis showed that the ratio of ECs_Lamb1+ cells was significantly up-regulated in the Fracture group; pseudotime analysis showed that ECs_Lamb1- cells were gradually reduced over time, whereas ECs_Lamb1+ cells were gradually expanding along the trajectories to reach a maximum at the end of the trajectory; pathway enrichment analyses revealed that ECs_Lamb1+ cells were mainly associated with several signaling pathways regulating cell proliferation, differentiation, repair, angiogenesis, and inflammatory responses, such as PI3K-Akt signaling pathway, Wnt/β-catenin, and MAPK. The results of basic assays demonstrated that successful knockdown of Lamb1 expression via siRNA-LAMB1 was detrimental to HUVEC proliferation, migration, and tube formation, and could suppress the expression of wnt3a, GSK-3β, β-catenin, and VEGFA; whereas, HY-141873 in combination with siRNA-LAMB1 partially reversed the down-regulated wnt3a, GSK-3β, β-catenin, and VEGFA expression, and HUVEC proliferation, migration, and tube formation were partially improved.

CONCLUSION

Lamb1 promotes fracture repair and healing by up-regulating VEGFA expression via the activation of Wnt signaling pathway to catalyze EC growth and migration and induce endothelial angiopoiesis.

Effectiveness of the Association of Fibrin Scaffolds, Nanohydroxyapatite, and Photobiomodulation with Simultaneous Low-Level Red and Infrared Lasers in Bone Repair

Biomaterials and biopharmaceuticals for correcting large bone defects are a potential area of translational science. A new bioproduct, purified from snake venom and fibrinogen from buffalo blood, aroused interest in the repair of venous ulcers. Expanding potential uses, it has also been used to form biocomplexes in combination with bone grafts, associated with physical therapies or used alone. The aim of this preclinical study was to evaluate low-level laser photobiomodulation (PBM) in critical defects in the calvaria of rats filled with nanohydroxyapatite (NH) associated with the heterologous fibrin biopolymer (HFB). Sixty animals were used, divided into six groups (n = 10 each): G1 (NH); G2 (HFB); G3 (NH + HFB); G4 (NH + PBM); G5 (HFB + PBM); G6 (NH + HFB + PBM). PBM simultaneously used red (R) and infrared (IR) light emission, applied intraoperatively and twice a week, until the end of the experiment at 42 days. Microtomography, bone formation can be seen initially at the margins of the defect, more evident in G5. Microscopically, bone formation demonstrated immature and disorganized trabeculation at 14 days, with remnants of grafting materials. At 42 days, the percentage of new bone formed was higher in all groups, especially in G5 (HFB, 45.4 ± 3.82), with collagen fibers at a higher degree of maturation and yellowish-green color in the birefringence analysis with Picrosirius-red. Therefore, it is concluded that the HFB + PBM combination showed greater effectiveness in the repair process and presents potential for future clinical studies.

An Overview on the Big Players in Bone Tissue Engineering: Biomaterials, Scaffolds and Cells

Presently, millions worldwide suffer from degenerative and inflammatory bone and joint issues, comprising roughly half of chronic ailments in those over 50, leading to prolonged discomfort and physical limitations. These conditions become more prevalent with age and lifestyle factors, escalating due to the growing elderly populace. Addressing these challenges often entails surgical interventions utilizing implants or bone grafts, though these treatments may entail complications such as pain and tissue death at donor sites for grafts, along with immune rejection. To surmount these challenges, tissue engineering has emerged as a promising avenue for bone injury repair and reconstruction. It involves the use of different biomaterials and the development of three-dimensional porous matrices and scaffolds, alongside osteoprogenitor cells and growth factors to stimulate natural tissue regeneration. This review compiles methodologies that can be used to develop biomaterials that are important in bone tissue replacement and regeneration. Biomaterials for orthopedic implants, several scaffold types and production methods, as well as techniques to assess biomaterials' suitability for human use-both in laboratory settings and within living organisms-are discussed. Even though researchers have had some success, there is still room for improvements in their processing techniques, especially the ones that make scaffolds mechanically stronger without weakening their biological characteristics. Bone tissue engineering is therefore a promising area due to the rise in bone-related injuries.

Research advances of nanomaterials for the acceleration of fracture healing

The bone fracture cases have been increasing yearly, accompanied by the increased number of patients experiencing non-union or delayed union after their bone fracture. Although clinical materials facilitate fracture healing (e.g., metallic and composite materials), they cannot fulfill the requirements due to the slow degradation rate, limited osteogenic activity, inadequate osseointegration ability, and suboptimal mechanical properties. Since early 2000, nanomaterials successfully mimic the nanoscale features of bones and offer unique properties, receiving extensive attention. This paper reviews the achievements of nanomaterials in treating bone fracture (e.g., the intrinsic properties of nanomaterials, nanomaterials for bone defect filling, and nanoscale drug delivery systems in treating fracture delayed union). Furthermore, we discuss the perspectives on the challenges and future directions of developing nanomaterials to accelerate fracture healing.

Special Issue: Bioceramics, Bioglasses, and Gels for Tissue Engineering

Undoubtedly, biomaterials such as bioceramics, bioactive glasses, and gels have attracted a wide range of research interest in the field of tissue engineering (TE), as they facilitate the essential support and environment for cells to grow, differentiate, and, specifically, regenerate new tissues [...].