Novel Angiogenic and Angiocrine Factors in Bone Microenvironment: Therapeutic Potential for Bone Repair

Blood vessels serve as conduits that connect the entire body, playing a crucial role in supporting tissue growth and maintaining homeostasis. Endothelial cells (ECs) line the inner surface of blood vessels. In conjunction with pericytes, they are indispensable for organ development and tissue homeostasis. This is accomplished through the production of paracrine signalling molecules known as angiocrine factors. Within the skeletal system, angiocrine factors derived from ECs, in combination with angiogenic factors released by bone cells, coordinate the intercellular communication within the bone microenvironment. Interestingly, the role of EGFL family proteins such as EGFL7 and EGFL6 have been identified in the bone microenvironment, which regulate the coupling effect of angiogenesis and osteogenesis, and bone defect repair. Gaining an understanding of the diverse mechanisms through which EC - derived angiocrine factors regulate bone and cartilage homeostasis, as well as their involvement in pathogenesis, is a significant step forward in developing potential therapeutic strategies for skeletal diseases.