Figure 8.

Diagram depicting a possible mechanism governing ectopic mineralisation in the tissue‐engineered skeletal muscle construct. C2C12 cells cultured in a three‐dimensional (3D) environment contain a population of cells that are able to fuse to form myotubes and a smaller population of cells that remain unfused, the so‐called ‘reserve’ cells. In the presence of osteoinductive factors, such as bone morphogenetic protein 2 (BMP2) or platelet derived growth factor (PDGF)‐BB, a proportion of these ‘reserve’ cells adopts a Sca‐1⁺/CD73⁺ phenotype. The phenotypically altered Sca‐1⁺/CD73⁺ population is osteogenic in nature and able to deposit a mineralized matrix. However, mineralization of the Sca‐1⁺/CD73⁺ population is mediated by the presence of pro‐inflammatory cytokines such as tumour necrosis factor α and interleukin 1. Hence, it is proposed that factors such as the level of inflammation, timing of non‐steroidal anti‐inflammatory drug (NSAID) administration, and relative abundance of osteoinductive proteins are likely to influence the outcome