Expression of metalloproteinases (MMP-1, MMP-2, and MMP-9) and their inhibitors (TIMP-1 and TIMP-2) in schistosomal portal fibrosis

Focal extracellular matrix degradation morphologically identified in human portal pipestem fibrosis due to Schistosoma mansoni did not express immunoh istochemical reactivity for metalloproteinases (MMP-1, MMP-2, and MMP-9) an d their inhibitors (TIMP-1 and TIMP-2). However, when active schistosomal p eriovular granulomas were present, a strong reactivity for MMP-1, MMP-2, TI MP-1, and TIMP-2 was observed. No reactivity was ever observed for MMP-9. H owever, the positive pattern of immunohistochemical expression was not seen in old fibrotic periovular granulomas, which were sometimes situated in ot her areas of the same microscopic section. Positive staining for MMPs and T IMPs was observed at the same time in hepatocytes and within the apical por tion of bile duct epithelium. These findings are consistent with the concep t that matrix degradation in recent and old fibroses, in addition to differ ing at the ultrastructural level, also differs in immunohistochemical expre ssion of metalloproteinases and their inhibitors.