MMP9 and inflammatory bowel disease: Moreover, the MMP-9 level is markedly elevated in intestinal tissue, serum, and stool of patients with IBD and closely correlates with the disease activity and degree of inflammation [9, 10], while plasma matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP) were demonstrated to increase in the peripheral blood sample of patients with IBD, suggesting a positive correlation with endoscopic mucosal injury, disease activity, clinical activity, and CRP [11].