Intestinal permeability in a patient with liver cirrhosis

Abstract

Liver cirrhosis is a worldwide public health problem, and patients with this disease are at high risk of developing complications, bacterial translocation from the intestinal lumen to the mesenteric nodes, and systemic circulation, resulting in the development of severe complications related to high mortality rate. The intestinal barrier is a structure with a physical and biochemical activity to maintain balance between the external environment, including bacteria and their products, and the internal environment. Patients with liver cirrhosis develop a series of alterations in different components of the intestinal barrier directly associated with the severity of liver disease that finally increased intestinal permeability. A "leaky gut" is an effect produced by damaged intestinal barrier; alterations in the function of tight junction proteins are related to bacterial translocation and their products. Instead, increasing serum proinflammatory cytokines and hemodynamics modification, which results in the appearance of complications of liver cirrhosis such as hepatic encephalopathy, variceal hemorrhage, bacterial spontaneous peritonitis, and hepatorenal syndrome. The intestinal microbiota plays a fundamental role in maintaining the proper function of the intestinal barrier; bacterial overgrowth and dysbiosis are two phenomena often present in people with liver cirrhosis favoring bacterial translocation. Increased intestinal permeability has an important role in the genesis of these complications, and treating it could be the base for prevention and partial treatment of these complications.

Keywords: bacterial translocation; hepatic encephalopathy; intestinal permeability; liver cirrhosis; spontaneous bacterial peritonitis; variceal hemorrhage.

Figure 1

Components of the intestinal barrier. It is composed of intestinal microbiota, a mucin layer with IgA immunoglobulin (and other defense proteins) covering the mixed columnar epithelial cells (enterocytes, globet cells, enterochromaffin cells and intestinal stem cells). Subepithelial region containing the lamina propria, the enteric nervous system, connective tissue and muscle layers. Intraepithelial lymphocytes are above, underlying basement membrane. There are many differents immune cells, like macrophages, dendritic cells, plasma cells, lymphocytes and in some cases, neutrophils, and organized lymphoid tissue like lymphoid structures compound as the Peyer’s patch (terminal ileum), containing M cells, dendritic cells and lymphocytes. Note: Adapted with permission from Salvo-Romero E, Alonso Cotoner C, Pardo-Camacho C, et al. The intestinal barrier function and its involvement in digestive disease. Rev Esp Enferm Dig. 2015;107:686–696. Abbreviations: CNS, central nervous system; ENS, enteric nervous system; IEC, intestinal epithelial cell; IESC, intestinal epithelial stem cell; IgA, immunoglobulin A; EC, enterochromaffin cell; DC, dendritic cells; PC, plasma cell.