Chronic pancreatitis: evolving paradigms.
Chronic pancreatitis (CP) is characterized by progressive fibrosis, pain and/or loss of exocrine and endocrine functions. With the identification and characterization of pancreatic stellate cells (PSCs), the pathogenesis of CP and pancreatic fibrosis is now better understood. Molecular mediators shown to regulate the pathogenesis include transforming growth factor-beta, platelet-derived growth factor, and proinflammatory cytokines such as interleukin (IL)-1, IL-6 and tumor necrosis factor-alpha. Besides these, the roles of cyclooxygenase (COX)-2 and apoptosis-related proteins have also been implicated in the pathogenesis. Furthermore, molecular pathways involving mitogen-activated protein kinases, phosphatidylinositol 3-kinase, Ras superfamily G proteins, serine threonine protein kinase Raf-1 and peroxisome proliferator-activated receptor-gamma (PPAR-gamma) have been elucidated. Newer pathobiologic concepts concerning pain generation have also been put forward. Understanding the pathogenesis has led to the identification of novel molecular targets and the development of newer potential therapeutic agents. Those found to retard the progression of experimental CP and fibrosis in animal models include antioxidants, a Japanese herbal medicine called Saiko-keisi-to (TJ 10), the PPAR-gamma ligand troglitazone, the protease inhibitor Camostat mesilate, and Lovastatin.