Matrix metalloproteinases (MMPs) are a large group of zinc-dependent extracellular endopeptidase proteinases involved in the cleavage of extracellular matrix macromolecules. MMPs play an important role in normal physiology, migration of inflammatory cells and the repair process after tissue damage. In this book, the authors present current research in the study of the biology, functions and clinical implications of matrix metalloproteinases. Topics discussed include TGF-B and MMPs as a complex regulatory loop in tumor progression; MMPs role in the pathogenesis of osteoarthritis; gelatinases in the skin; detecting MMP activity in vivo; MMPs in renal fibrosis; macrophage migration inhibitory factor as a mediator of MMP production; MMP regulation by macrolides in cardiac disorders and MMPs in neural plasticity and disease.