ECHINOCOCCUS-MULTILOCULARIS - RELATIONSHIP BETWEEN SUSCEPTIBILITY RESISTANCE AND LIVER FIBROGENESIS IN EXPERIMENTAL MICE/

To analyze collagen and other matrix protein deposits in experimental alveolar echinococcosis as well as the expression of lysyl oxidase, th e enzyme that initiates the first steps in the pyridinoline cross-link ing of collagen, and to establish a relationship between resistance/su sceptibility to Echinococcus multilocularis is larval growth and fibro genesis, we compared AKR/J mice (susceptible to E. multilocularis infe ction) with NMRI mice (resistant hosts) in this study. Collagen deposi ts in the lesions were evaluated using a colorimetric method; the natu re of matrix proteins involved in the periparasitic fibrosis and lysyl oxidase expression were assessed using immunostaining on tissue secti ons. The results obtained in this sequential study confirm that fibrog enesis is an important aspect of the host immune reaction against para sitic development and that both the extent and the course of matrix pr otein deposition differ in the liver of susceptible and resistant mice , respectively. The long-lasting expression of alpha-actin and lysyl o xidase by host cells in NMRI mice suggests that in this resistant stra in, fibrosis was not only more developed but also more highly cross-li nked and, thus, less sensitive to collagenases than in susceptible mic e. A very strong expression of lysyl oxidase by parasitic cells was ob served in both strains of mice; the observation that E. multilocularis itself has a role in lysyl oxidase crosslinking of host collagens can be hypothesized and would be a new example of parasite-host interplay .