^* Injectable Graft Substitute Active on Bone Tissue Regeneration.

Current bone regeneration strategies often rely on autografts or synthetic scaffolds. Injectable scaffolds offer a minimally invasive alternative for bone repair. However, few materials combine both osteoconductive and osteoinductive properties. Lysophosphatidic acid (LPA) has been linked to cytoskeletal changes in bone cells. 1α,25-dihydroxyvitamin D3 (1,25D3) is known to support extracellular matrix maturation. Combining these agents in a collagen scaffold could enhance bone healing outcomes. This gap motivated the development of a 3D collagen scaffold enriched with LPA and 1,25D3. The potential of such a scaffold for clinical use remains underexplored.

The goal was to create an injectable scaffold that supports bone regeneration. This scaffold was designed to deliver LPA and 1,25D3 in a collagen matrix. The specific problem addressed is the need for a scaffold that accelerates bone repair. The motivation stems from the limitations of current grafting materials. The scaffold was tested using an in vitro model of bone fracture. Researchers aimed to evaluate how LPA and 1,25D3 affect osteoblast behavior. The study focused on gel contraction, cell migration, and extracellular matrix production. The findings could inform the design of injectable bone graft substitutes.

A three-dimensional collagen gel was formulated with lysophosphatidic acid and 1,25D3. Human primary osteoblasts were used in a 3D culture model of bone fracture. Gel contraction was measured as an indicator of osteoblast activity. Cell concentration effects were analyzed to assess scaffold responsiveness. LPA’s influence on actin cytoskeleton and myosin light chain phosphorylation was studied. 1,25D3’s role in extracellular matrix maturation was evaluated separately. The scaffold’s osteoconductive properties were assessed through cell proliferation and migration. Results were compared to determine the individual and combined effects of LPA and 1,25D3.

The collagen gel contracted in response to osteoblast activity and LPA presence. Gel contraction increased with higher cell concentrations and LPA levels. LPA induced actin cytoskeleton reorganization and myosin light chain phosphorylation. These changes promoted cell apposition and fragment fastening in the model. LPA also stimulated osteoblast proliferation, differentiation, and migration. 1,25D3 did not enhance gel contraction but improved extracellular matrix quality. The scaffold supported cell migration from the bone defect site into the gel. Together, LPA and 1,25D3 enriched the scaffold with osteoconductive properties.

The collagen scaffold with LPA and 1,25D3 supports cell migration and matrix maturation. LPA enhances gel contraction through cytoskeletal changes in osteoblasts. 1,25D3 contributes to extracellular matrix quality without affecting gel contraction. The scaffold’s injectable nature allows for minimally invasive bone defect filling. These findings suggest the scaffold could be useful in sinus lift and fracture repair. The combination of LPA and 1,25D3 may improve bone regeneration outcomes. Further studies are needed to validate the scaffold’s performance in vivo. This scaffold represents a promising candidate for bone tissue engineering.