A MODERN VIEW ON REPARATIVE OSTEOGENESIS: MAIN STAGES AND THEIR PATTERNS

Abstract

Introduction. Reparative osteogenesis is a staged mechanism that ensures the restoration of damaged bone tissue. The study and summarization of current data about bone defect regeneration is the basis for the search and development of methods to improve this process. The aim of the study is to analyze and systematize the current data about reparative osteogenesis, describe the main stages and their patterns. Materials and methods. Searching the relevant sources using online scientific databases and keywords. Selection of publications for review. Further analysis and synthesis of information. The results. Despite different interpretations of the stages of reparative osteogenesis by researchers, they all describe the same coordinated process. The following key stages have been identified: haematoma formation, inflammation, MSC involvement and angiogenesis, cartilage, connective and bone tissue formation, their subsequent reorganisation, ossification and remodelling. Each of these stages involves specific cellular elements, local and general regulatory factors. The development of osteogenic cells and mechanisms of intercellular interaction, as well as the main signalling pathways and molecules (Wnt, RANK/RANKL/OPG, BMPs, HIF, etc.) that regulate osteo- and angiogenesis are described. The role of hypoxia in the process of bone regeneration and angiogenesis is highlighted. The H-type vessels and their participation in the regulation of osteogenesis are considered. Attention is paid to the phenomenon of ‘chondrocyte transdifferentiation’, which is one of the sources of osteoblasts during endochondral ossification. In the context of remodelling, the law of bone biomechanics and piezoelectric adaptive remodelling, as well as bone multicellular units as microsystems that ensure the restructuring of coarse fibrous bone tissue into lamellar bone tissue, are described. Conclusions. Reparative osteogenesis is a complicated and coordinated process at both the cellular and molecular levels. The regeneration process depends on numerous local and systemic factors and the optimization search is carried out at each stage