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    Poster Networking

    Hemostatic Systems in Cancer, Inflammation and Immunity

    Poster Networking Session

    PB0726 - Plasminogen is crucial for early phase Echinococcus multilocularis infection but not for alveolar echinococcosis progression

    Monday, June 26, 2023
    18:30 – 19:30 ET
    Room: Exhibition
    Background: Infection with the tapeworm Echinococcus multilocularis causes alveolar echinococcosis (AE), one of the most life-threatening zoonotic diseases. Upon oral ingestion of eggs, larvae migrate to the liver and proliferate invasively as a so called metacestode, which can metastasize to distant foci. Parasites are known to use the broad proteolytic activity of plasmin to evade host defense and ease tissue migration. To study its importance in E. multilocularis infections, we used plasminogen-deficient mice and the plasminogen activation inhibitor tranexamic acid (TXA).

    Aims: Evaluation of the impact of plasminogen in E. multilocularis infections and assessment of the therapeutic potential of tranexamic acid in alveolar echinococcosis.

    Methods: C57Bl/6 wild-type and plasminogen deficient mice were orally infected with 1000 E. multilocularis eggs. TXA treatment started one week or one month after infection with 10 mg/ml in tab water. Organs of plasminogen deficient mice were analyzed after 77 days and those of TXA treated mice after 120 days.

    Results: Hepatic metacestode lesions were profoundly reduced by 88% in plasminogen deficient mice, together with decreased circulated Th2 cells. In contrast, TXA treatment did not lead to reduced metacestode growth. Delayed TXA administration did even result in 40 % more lesions, with decreased circulating Th17/Th22 cells and a trend towards more Th1 cells.

    Conclusion(s): Our data suggests that plasminogen plays a crucial part in E. multilocularis pathogenesis. A lack of plasminogen massively reduced metacestode lesions but TXA treatment did not result in decreased metacestode burden. We conclude that plasminogen or plasmin are critical for the early phase of E. multilocularis infection but not for invasive metacestode growth.