In the present study, we revert and complement published data on MMP-9 gene deficiency in three animal models of colitis: an acute and a chronic DSS-mediated model of colonic inflammation mimicking various aspects of UC and an acute 2,4,6-trinitrobenzenesulfonic acid (TNBS)-mediated model that more closely resembles CD. Here, MMP9 is linked to Cowden disease.