Influence of Scaffold Microarchitecture on Angiogenesis and Regulation of Cell Differentiation during the Early Phase of Bone Healing: A Transcriptomics and Histological Analysis

Abstract

The early phase of bone healing is a complex and poorly understood process. With additive manufacturing, we can generate a specific and customizable library of bone substitutes to explore this phase. In this study, we produced tricalcium phosphate-based scaffolds with microarchitectures composed of filaments of 0.50 mm in diameter, named Fil050G, and 1.25 mm named Fil125G, respectively. The implants were removed after only 10 days in vivo followed by RNA sequencing (RNAseq) and histological analysis. RNAseq results revealed upregulation of adaptive immune response, regulation of cell adhesion, and cell migration-related genes in both of our two constructs. However, significant overexpression of genes linked to angiogenesis, regulation of cell differentiation, ossification, and bone development was observed solely in Fil050G scaffolds. Moreover, quantitative immunohistochemistry of structures positive for laminin revealed a significantly higher number of blood vessels in Fil050G samples. Furthermore, µCT detected a higher amount of mineralized tissue in Fil050G samples suggesting a superior osteoconductive potential. Hence, different filament diameters and distances in bone substitutes significantly influence angiogenesis and regulation of cell differentiation involved in the early phase of bone regeneration, which precedes osteoconductivity and bony bridging seen in later phases and as consequence, impacts the overall clinical outcome.

Prioritizing Biomaterial Driven Clinical Bioactivity Over Designing Intricacy during Bioprinting of Trabecular Microarchitecture: A Clinician’s Perspective

“…Both macro- and microporosities within a biomaterial play crucial roles in promoting osteogenesis and angiogenesis (Figure ). − Larger macropores, with an average size exceeding 100 μm, facilitate osteogenesis, and macropores exceeding 500 μm facilitate angiogenesis. , …”

Organoid Models and Next-Generation Sequencing for Bone Marrow and Related Disorders

“…Their findings indicated that the phagocytosis of these degradation products spurred oxidative stress and nudged macrophages toward an inflammatory state (M1). In a different investigation, Guerrero et al evaluated two distinct types of bone substitute constructs for their application in the early phases of bone healing, using RNA-seq and histology as tools for comparison [102]. The results demonstrated that while both constructs exhibited robust expression of genes linked to cell adhesion, migration, and adaptive immune responses, one construct demonstrated elevated expression of genes involved with ossification, bone development, and angiogenesis.…”