Department of Medicine and Genetics, Division of Gastroenterology and Liver Diseases, Marion Bessin Liver Research Center, Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, New York, NY 10461, USA
Agostino Di Ciaula
Clinica Medica “A. Murri”, Department of Biomedical Sciences & Human Oncology, University of Bari Medical School, 70124 Bari, Italy
The largest surface of the human body exposed to the external environment is the gut. At this level, the intestinal barrier includes luminal microbes, the mucin layer, gastrointestinal motility and secretion, enterocytes, immune cells, gut vascular barrier, and liver barrier. A healthy intestinal barrier is characterized by the selective permeability of nutrients, metabolites, water, and bacterial products, and processes are governed by cellular, neural, immune, and hormonal factors. Disrupted gut permeability (leaky gut syndrome) can represent a predisposing or aggravating condition in obesity and the metabolically associated liver steatosis (nonalcoholic fatty liver disease, NAFLD). In what follows, we describe the morphological-functional features of the intestinal barrier, the role of major modifiers of the intestinal barrier, and discuss the recent evidence pointing to the key role of intestinal permeability in obesity/NAFLD.
