Figure 2.

The matrix-degrading properties of fibroblasts in the infarcted myocardium. During the inflammatory phase of infarct healing, pro-inflammatory cytokines, such as interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and IL-6 stimulate the expression and secretion of matrix metalloproteinases (MMPs) that degrade the extracellular matrix, setting the stage for the replacement of damaged tissue with a collagen-based scar. During the inflammatory and early proliferative phases of infarct healing, the induction of membrane-type matrix metalloproteinases (MT-MMPs) on the cell surface plays an important role in fibroblast migration, thus localizing the reparative fibroblasts to the area of infarction.