Skeletal Resident Stem Cells

Abstract

Objective: The extracellular matrix of bone is embedded with chemical variants of hydroxyapatite crystals formed by the mineralization process and collagenous and noncollagenous proteins. The primary cellular elements of bone involved in the production, maintenance, and resorption are osteoblasts, osteocytes, and osteoclasts. In this chapter, mesenchymal stromal cells (MSCs), a common term for skeletal resident stem cells, will be utilized. Bone marrow, periosteum, and growth plates have all been found to contain MSCs. The first human tissue in which MSCs were identified was bone marrow. By producing osteoblasts, MSCs in the bone marrow support hematopoiesis and uphold bone biology. Scaffolds are frequently used in bioengineering procedures to simulate the mineral component of the bone extracellular matrix. The use of spheroids for scaffold-free tissue constructs and even a combination of scaffold-based and scaffold-free bioprinting have been mentioned as current alternatives. As bone is a highly vascularized tissue, the role of the circulatory system in supplying progenitor cells with nutrients and oxygen they need to grow, repair, and stay healthy is highlighted during embryogenesis and bone repair. The combined and balanced action of mesenchymal and angiogenic progenitors, essential to bone homeostasis, associated with 3D bioprinting technology is emerging as a promising regenerative medicine tool for treating complex diseases such as fracture nonunion and avascular necrosis of the femoral head.