An In Vitro and In Vivo Comparison of Osteogenic Differentiation of Human Mesenchymal Stromal/Stem Cells

Figure 1

Schematic representation of the bone remodelling process. Solid lines indicate differentiation, and dotted lines indicate stimulation. Osteocytes within bone tissue stimulate osteoclast progenitor cells to differentiates into osteoclasts. Osteoblasts can also stimulate osteoclast progenitor cells through RANK/RANKL binding. Once the defective bone tissue is cleared, macrophage-like cells smooth the resorbed bone tissue. Before undergoing apoptosis, osteoclasts recruit osteoblasts for matrix deposition. Osteoblasts stimulate the release of osteoprotegerin (OPG) that acts as a soluble decoy and inhibits osteoclast differentiation. Adapted from Wittkowske et al. [12], bone remodelling cycle, https://creativecommons.org/licenses/by/4.0/legalcodehttp://creativecommons.org/licenses/by/4.0/. MSC: mesenchymal stroma/stem cell; RANK: receptor activator of nuclear factor kappa-Β; RANKL: receptor activator of nuclear factor kappa-Β ligand; OPG: osteoprotegerin.