Covalent cross-linking of liver collagen by pyridinoline increases in the course of experimental alveolar echinococcosis.

We report that covalent cross-linking of collagen molecules by pyridinoline increases significantly in liver in a murine model of alveolar echinococcosis. The highest amount of pyridinoline per collagen molecule (up to 3.5 fold the control values) is found in liver parasitic lesions. It is also increased, but to a far lesser extent, at distance from the fibrotic areas, in macroscopically normal zones of the liver, suggesting that the increase in mature collagen cross-linking occurring in the fibrogenesis due to Echinococcus multilocularis infection involves the whole liver. The comparison of these data with those we have obtained in another parasitic disease, murine schistosomiasis leading to a milder liver fibrosis, largely reversible following chemotherapy, supports a relationship between the liver pyridinoline level and the severity of liver fibrosis. Pyridinoline could be a tissular marker of chronic liver fibrosis in parasitic diseases.