Gut microbiota and gastrointestinal tract, liver and pancreas. From physiology to pathology

The human organism is colonized by an enormous number of microbes, both on its surface and its inside. The set of microorganisms living in our gut is defined gut microbiota, which is considered now a functional organ of our body. Gut microbiota plays a key role in regulating both health and disease; its quantitative and/or qualitative variations, by altering the homeostasis between microbes and host, may lead to the onset of various diseases. Dis¬orders associated with the impairment of gut microbiota include functional gastrointestinal diseases, intestinal infectious diseases, inflammatory bowel disease (IBD), liver and pancreatic diseases, gastrointestinal malignancies, but also metabolic syndrome and diabetes and obesity, allergic diseases, autism, and others. The intestinal microbiota is considered a signaling hub that integrates environmental inputs, such as diet, with genetic and immune signals to affect the host’s metabolism, immunity, including autoimmunity and autoinflammation