Matrix Metalloproteinases in Parasitic Infections

Matrix metalloproteinases (MMPs) constitute a wide family of more than 20 distinct endopeptidases, either secreted or membrane-bound. They are involved in many physiological (embryogenesis, precursor or stem cell mobilization, tissue remodeling during wound healing, etc.) as well as pathological (inflammation, tumor progression and metastasis in cancer, vascular pathology, etc.) situations. These proteinases have been considered in the past exclusively for their degradation ability of molecules of extracellular matrix (ECM) (e.g., collagen, laminin, fibronectin) as well as that to release hidden epitopes from the ECM. In more recent years, it has been completely clarified that these enzymes are also involved in the immune response, acting on cytokines, hormones, and chemokines. Among many others, the so-called gelatinases, MMP-2, and MMP-9 are produced by neutrophils, macrophages, and monocytes. When infection is associated with leukocyte influx into specific organs, immunopathology and following tissue damage may occur, facilitated by gelatinases. The focus of this chapter will be on the participation of MMPs and in particular of gelatinases in either protozoan or helminth infections. A well-studied model is represented by cerebral malaria, for example, where MMPs play a crucial role in the pathogenesis of such disease. Also trypanosomosis and toxoplasmosis will be considered for protozoan infections, as well as neurocysticercosis, angiostrongyloidosis and trichinellosis, for helminth infections.