S100A8/A9 promotes MMP-9 expression in the fibroblasts from cardiac rupture after myocardial infarction by inducing macrophages secreting TNFα.

The level of S100A8/A9 was upregulated in MI patients with CR. S100A8/A9 induced the activation of NF-κB and expression of MMP-9 protein in HCF cells through facilitating secretion of TNFα from macrophages, which may play a role in triggering extracellular matrix degradation and CR.