New therapeutical targets in ulcerative colitis: the importance of ion transporters in the human colon

Introduction: The absorption of water and ions is an important function of colonic epithelial cells. Despite the comprehensive animal studies, there are only scarce data on the ion transporter activities of the normal and inflamed human colon. The aim of our study was to determine the expressional and functional characteristics of Na+/H+ exchangers (NHE) 1–3 and Cl-/HCO3- exchangers (AE) in primary colonic crypts in control patients and in patients with ulcerative colitis (UC). Methods: Colonic biopsies were obtained from normal and inflamed mucosa of patients undergoing colonoscopy. After collagenase digestion, the isolated colonic crypts were loaded with the pH sensitive fluorescent dye BCECF. Intracellular pH (pHi) was measured by microspectrofluorimetry. The mRNA expression of NHEs and the SLC26A3 Cl-/HCO3- exchangers (DRA) was assessed by real-time PCR.