The zymogen and active form of MMP-2 and MMP-9 were quantitated in the culture medium with specific ELISA; these assays confirmed that, when the stimulus was applied on both sides, MMP-9 increased 4-fold in the CHD region, whereas in the AMN the increase was 8-fold with respect to the respective controls (Figure 2a). Here, MMP9 is linked to coronary artery disorder.