Gut-liver axis and probiotics: their role in non-alcoholic fatty liver disease.
The incidence of obesity and its related conditions, including non-alcoholic fatty liver disease (NAFLD), has dramatically increased in all age groups worldwide. Given the health consequences of these conditions, and the subsequent economic burden on healthcare systems, their prevention and treatment have become major priorities. Because standard dietary and lifestyle changes and pathogenically-oriented therapies (e.g., antioxidants, oral hypoglycemic agents, and lipid-lowering agents) often fail due to poor compliance and/or lack of efficacy, novel approaches directed toward other pathomechanisms are needed. Here we present several lines of evidence indicating that, by increasing energy extraction in some dysbiosis conditions or small intestinal bacterial overgrowth, specific gut microbiota and/or a "low bacterial richness" may play a role in obesity, metabolic syndrome, and fatty liver. Under conditions involving a damaged intestinal barrier ("leaky gut"), the gut-liver axis may enhance the natural interactions between intestinal bacteria/bacterial products and hepatic receptors (e.g., toll-like receptors), thus promoting the following cascade of events: oxidative stress, insulin-resistance, hepatic inflammation, and fibrosis. We also discuss the possible modulation of gut microbiota by probiotics, as attempted in NAFLD animal model studies and in several pilot pediatric and adult human studies. Globally, this approach appears to be a promising and innovative add-on therapeutic tool for NAFLD in the context of multi-target therapy.
Giulia Paolella, Luca Pierri, Marco Poeta, Martina Di Stasi, Pietro Vajro, Department of Medicine and Surgery, University of Salerno, 84081 Baronissi (Salerno), Italy.
Giulia
G
Paolella
Giulia Paolella, Luca Pierri, Marco Poeta, Martina Di Stasi, Pietro Vajro, Department of Medicine and Surgery, University of Salerno, 84081 Baronissi (Salerno), Italy.
Claudia
C
Mandato
Giulia Paolella, Luca Pierri, Marco Poeta, Martina Di Stasi, Pietro Vajro, Department of Medicine and Surgery, University of Salerno, 84081 Baronissi (Salerno), Italy.
Luca
L
Pierri
Giulia Paolella, Luca Pierri, Marco Poeta, Martina Di Stasi, Pietro Vajro, Department of Medicine and Surgery, University of Salerno, 84081 Baronissi (Salerno), Italy.
Marco
M
Poeta
Giulia Paolella, Luca Pierri, Marco Poeta, Martina Di Stasi, Pietro Vajro, Department of Medicine and Surgery, University of Salerno, 84081 Baronissi (Salerno), Italy.
Martina
M
Di Stasi
Giulia Paolella, Luca Pierri, Marco Poeta, Martina Di Stasi, Pietro Vajro, Department of Medicine and Surgery, University of Salerno, 84081 Baronissi (Salerno), Italy.
Pietro
P
Vajro
D000818:Animals; D018988:Bacterial Translocation; D004195:Disease Models, Animal; D064806:Dysbiosis; D054884:Host-Pathogen Interactions; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000382:microbiology*; D008099:Liver / Q000378:metabolism / Q000382:microbiology*; D064307:Microbiota; D065626:Non-alcoholic Fatty Liver Disease / Q000175:diagnosis / Q000378:metabolism / Q000382:microbiology / Q000628:therapy*; D019936:Probiotics / Q000627:therapeutic use*; D015398:Signal Transduction; D016896:Treatment Outcome
Bacterial translocation; Barrier function; Gut-liver axis; Intestinal microbiota; Non-alcoholic fatty liver disease; Probiotics; Small intestinal bacterial overgrowth