Figure 1.

The temporal host response upon implantation of a cell-laden scaffold. An acute inflammatory response initiates as part of the surgical implantation, which creates a wound. This initial response is accompanied by recruitment of leukocytes, notably inflammatory macrophages (shown in red), which release pro-inflammatory cytokines. If the scaffold is non-biologic, the host response evolves eventually shifting to an altered healing phase that is accompanied by a polarization shift in the macrophage and formation of multinucleated foreign body giant cells (shown in green) and the eventual walling off of the implant by a fibrous capsule. The resolution of the foreign body response is the presence of macrophages and FBGCs at the implant surface, maintaining low grade chronic inflammation, and the isolation of the implant from the host tissue.