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Projekt Druckansicht

Der Einfluss der intestinalen Mikrobiota auf die nichtalkoholische Fettlebererkrankung im humanisierten Mausmodell und ihre zielgerichtete therapeutische Beeinflussung mit Bakteriophagen.

Antragstellerin Dr. Sonja Lang
Fachliche Zuordnung Gastroenterologie
Förderung Förderung von 2018 bis 2020
Projektkennung Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 401846036
 
Erstellungsjahr 2021

Zusammenfassung der Projektergebnisse

Whereas several studies demonstrated that patients with non-alcoholic fatty liver disease (NAFLD) have changes in the composition of the gut bacterial microbiota, we could show that NAFLD is also associated with a lower viral diversity and compositional changes of the intestinal virome. We could further demonstrate that the intestinal virome could contain information about the underlying disease stage, which might be helpful in the future to noninvasively identify patients at risk for disease progression. Viruses are the most abundant microbes in the gut. The majority belongs to bacteriophages, viruses that infect bacteria, replicate inside, and destroy them. In the setting of alcohol-associated liver disease (ALD) and particularly in alcoholic hepatitis, we demonstrated, that, in parallel to a decreased bacterial diversity, the diversity of the intestinal virome is increased. Besides, we observed a lower diversity of intestinal fungi with an overgrowth of Candida sp. in patients with alcoholic hepatitis and alcohol-use disorder when compared with non-alcoholic controls. Serum levels of Saccharomyces cerevisiae antibodies, as systemic immune response to fungal products or fungi were in parallel increased in ALD patients with more advanced disease and high levels were associated with a lower probability of survival. We further identified cytolysin, a twosubunit exotoxin that is secreted by Enterococcus faecalis (E. faecalis) to be highly associated with worse outcome in patients with alcoholic hepatitis. To determine whether cytolysin contributes to liver damage mediated by E. faecalis, mice were gavaged with a cytolytic E. faecalis strain or a non-cytolytic E. faecalis strain; the mice were then placed on a chronicbinge ethanol diet. Compared to mice gavaged with phosphate-buffered saline, mice fed with ethanol after they were gavaged with cytolytic E. faecalis developed more severe liver injury. Using humanized mice that were colonized with bacteria from the feces of patients with alcoholic hepatitis, we investigated the therapeutic effects of bacteriophages that target cytolytic E. faecalis. We found that these bacteriophages decrease cytolysin in the liver and abolish ethanol-induced liver disease in humanized mice. Altogether, the projects that I worked on during the fellowship allow a better understanding of the connection between the gut microbiota and the liver, which will eventually lead to improved health outcomes in the setting of NAFLD and ALD.

Projektbezogene Publikationen (Auswahl)

 
 

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