Infection as a Risk Factor in the Pathogenesis of Primary Biliary Cirrhosis: Pros and Cons

Primary biliary cirrhosis (PBC) is a chronic and slowly progressive cholestatic liver disease of autoimmune etiology, characterized by injury of the intrahepatic bile ducts that may eventually lead to cirrhosis and liver failure. Evidence suggests cardinal roles for both environmental factors and genetic susceptibility. Nevertheless, the absolute etiology of PBC is unclear, despite recent well-designed case-control studies that reported environmental risk factors, including infectious agents, for PBC. Of the reported infectious agents, some of them are not reproducible and remain controversial. However, infection is no doubt one of the major risks among the environmental factors. This is supported by the fact that infectious agents in autoimmune diseases express antigens resulting in molecular mimicry and xenobiotics that play a role in breaking tolerance. Taken together, recent findings from genome wide assays as well as novel animal models may enable us to better understand the mechanism of pathogenesis responsible for this disease

Effects of Motilin Receptor Agonists and Ghrelin in Human <i>motilin receptor</i> Transgenic Mice

Gastrointestinal motility is regulated by neural factors and humoral factors. Both motilin and ghrelin improve gastrointestinal motility, but many issues remain unclear. We prepared human motilin receptor transgenic (Tg) mice and performed experiments evaluating the effects of motilin, erythromycin (EM), and ghrelin. EM and ghrelin promoted gastric emptying (GE) when administered either peripherally or centrally to Tg mice. Atropine (a muscarinic receptor antagonist) counteracted GE induced by centrally administered EM, but not that induced by peripherally administered EM. The administration of EM in this model promoted the effect of mosapride (a selective serotonin 5-hydroxytryptamine 4 (5-HT4) receptor agonist), and improved loperamide (a &#956;-opioid receptor agonist)-induced gastroparesis. The level of acyl-ghrelin was significantly attenuated by EM administration. Thus, we have established an animal model appropriate for the evaluation of motilin receptor agonists. These data and the model are expected to facilitate the identification of novel compounds with clinical potential for relieving symptoms of dyspepsia and gastroparesis