Intestinal epithelial water transport

Intestinal epithelial water transport is a fundamental physiological process involving the massive flux of water across the intestinal mucosa to maintain systemic fluid balance and support digestion. This movement is not mediated by active water pumps but is driven by osmotic gradients created by the active transport of ions and solutes, such as sodium, chloride, and glucose (Kiela & Ghishan, 2016). The transport occurs via two main routes: the transcellular pathway, utilizing water-selective channels called aquaporins (e.g., AQP1, AQP3, AQP8) and solute co-transporters like SGLT1, and the paracellular pathway through tight junction proteins like claudins (Verkman, 2012). Dysregulation of these mechanisms is central to the pathogenesis of secretory diarrheas, inflammatory bowel diseases, and functional constipation. Therapeutic strategies do not usually target the water flux directly but rather modulate the ion transporters (e.g., CFTR, NHE3) or signaling pathways (e.g., Guanylate Cyclase C) that establish the driving osmotic forces (Masyuk et al., 2002). Drugs like linaclotide and tenapanor are used to manage these conditions by altering the secretion or absorption of ions, thereby correcting the bulk water distribution across the epithelium.

Other names

Bulk water distribution across the intestinal epitheliumIntestinal fluid transportTransepithelial water movementIntestinal water flux

Modulation of osmotic gradients through the regulation of ion transporters (e.g., CFTR, NHE3) and water channels (Aquaporins), or alteration of intestinal motility to influence the time available for water absorption.