Fascioliasis: bile duct collagen induced by proline from the worm [Fasciola hepatica]

We investigated whether collagen increases occur in the bile duct during fascioliasis, and their relationship to the release of proline by the worm. Experiments showed increased levels of collagen in the bile ducts of rats following 2 wk of infusion with proline or i.p. implantation with Fasciola. The increase in bile duct collagen in proline-infused animals and in worm-implanted animals could be completely inhibited to the amount in controls by 3,4-dehydroproline. These effects suggest that the hyperplasia of the bile duct that is induced by liver flukes involves stimulation of collagen deposition through their release of proline.