Review

Gut-Kidney Connection and Dietary Fibers: Roles of the Intestinal Barrier

Takuya SUZUKI1, 2 *

1 Graduate School of Biosphere Science, Hiroshima University
2 Graduate School of Integrated Sciences for Life, Hiroshima University

The intestinal epithelium provides a physical barrier that limits the permeation of luminal noxious molecules such as pathogens, toxins, and antigens, while allowing the appropriate absorption of nutrients and water. This barrier is achieved by different components including intercellular tight junction (TJ) structures, which regulate paracellular permeability. Disruption of the intestinal TJ barrier, followed by permeation of luminal noxious molecules, induces inflammation and perturbation of the mucosal immune system and, therefore, can act as a trigger for the development of intestinal and systemic diseases. Chronic kidney disease, a worldwide public health issue, is characterized by impaired renal function. Evidence demonstrates that chronic kidney disease often presents with intestinal hyperpermeability and systemic inflammation, although the underlying mechanisms are still unclear. Patients with chronic kidney disease also have profoundly altered intestinal microflora. Accordingly, the intestinal environment and the integrity of its barrier could be potential targets for treatments aimed at preventing or reducing chronic kidney disease. Dietary fibers exert various beneficial effects on health. Some studies have demonstrated that dietary fibers reduce the plasma levels of colon-derived uremic toxins such as indoxyl and p-cresyl sulfates through the alteration of microflora. Additionally, short-chain fatty acids, bacterial metabolites of dietary fibers, have the potential to enhance the integrity of the intestinal TJ barrier. In this review, we discuss the impact of dietary fibers in chronic kidney disease, with emphasis on the regulation of the intestinal TJ barrier and microflora.
Keywords: chronic kidney disease, dietary fiber, intestinal barrier, tight junction

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