Unique bone marrow blood vessels couple angiogenesis and osteogenesis in bone homeostasis and diseases
Yifan Zhao, Liang Xie
Abstract
Blood vessels serve as a versatile transport system and play crucial roles in organ development, regeneration, and stem cell behavior. In the skeletal system, certain capillaries support perivascular stem cells or osteoprogenitor cells and thereby regulate bone formation. Recent studies reported that a specialized capillary subtype, termed type H vessels, is shown to couple angiogenesis and osteogenesis in rodents and humans. They can be distinguished by specific cell surface markers, as the endothelial cells in the metaphysis and endosteum highly express the junctional protein CD31 and the sialoglycoprotein endomucin. Here, we provide an overview of the role of type H vessels in bone homeostasis and summarize their linkage with various cytokines to control bone cell behavior and bone formation. We also discuss the potential clinical application for bone disorders by targeting these specific vessels according to their physiological and pathobiological settings.