Liver damage [e.g. nonalcoholic fatty liver disease activity score (NAS), number of neutrophils, interleukin-6 (IL-6) protein concentration], markers of intestinal permeability (bacterial endotoxin, tight junction proteins), and NO homeostasis in the small intestine were determined in vivo as well as ex vivo in an everted sac model and in Caco-2 cells. The gene discussed is IL6; the disease is metabolic dysfunction-associated steatotic liver disease.