Microbial translocation in chronic liver diseases

The intestinal microflora is not only involved in the digestion of nutrients, butalso in local immunity, forming a barrier against pathogenic microorganisms. The derangement of the gut microflora may lead to microbial translocation, defined asthe passage of viable microorganisms or bacterial products (i.e., LPS,lipopeptides) from the intestinal lumen to the mesenteric lymph nodes and otherextraintestinal sites. The most recent evidence suggests that microbialtranslocation (MT) may occur not only in cirrhosis, but also in the early stageof several liver diseases, including alcoholic hepatopathy and nonalcoholic fattyliver disease. Different mechanisms, such as small intestinal bacterialovergrowth, increased permeability of intestinal mucosa, and impaired immunity,may favor MT. Furthermore, MT has been implicated in the pathogenesis of thecomplications of cirrhosis, which are a significant cause of morbidity andmortality in cirrhotic subjects. Therapeutic strategies aiming at modulating the gut microflora and reducing MT have focused on antibiotic-based options, such as selective intestinal decontamination, and nonantibiotic-based options, such asprokinetics and probiotics. In particular, probiotics may represent an attractivestrategy, even though the promising results of experimental models and limitedclinical studies need to be confirmed in larger randomized trials.