Anti-fibrotic effect of adipose-derived stem cells on fibrotic scars

Figure 3 Collagen degradation. Collagen type 1 and type 3 are the predominant collagen types in fibrosis. ECM homeostasis requires a balance between collagen production and collagen degradation. MMPs manage the collagen degradation, while TIMPs inhibit MMPs, therefore inhibiting degradation. MMPs need activation, which is inhibited by PAI1. So, when TGF-β₁ increases, PAI1 renders more inhibition of MMPs activation, therefore inhibiting ECM turnover/ remodeling and increasing fibrosis. MMP: Matrix metalloproteinase; TIMP: Tissue inhibitor of metalloproteinase; TGF-β1: Transforming growth factor beta; IL-1β: Interleukin-1β; PAI1: Plasminogen activator inhibitor 1.