Related Experiment Video
Updated: Apr 17, 2026

Generation of Human Nasal Epithelial Cell Spheroids for Individualized Cystic Fibrosis Transmembrane Conductance Regulator Study
Published on: April 11, 2018
Cystic fibrosis: model of pathogenesis based on the apical membrane potential
Beatrica Kurbel1, Saša Rapan2, Sven Kurbel3
1Department of Anesthesiology, Zagreb University Hospital, Zagreb; Croatia.
Abstract:
A simple model of cystic fibrosis (CF) is proposed, based on the apical membrane (ApM) potential. The ApM of epithelial cells is highly permeable to sodium and activation of CFTRs makes it permeable to chloride. Calculated ApM potentials of cells with activated cystic fibrosis transmembrane conductance regulators (CFTRs) are between the sodium and chloride Nernst values and thus allow rapid absorption of both ions in exocrine glands. In CF patients the potential is near the sodium Nernst value and thus more salt is left in the ducts. Simulation predicts that the sodium driving force increases more than 3.5 times if the ApM permeability for Cl- increases from 5-94% of the sodium permeability. In pancreatic ductal cells basolateral sodium bicarbonate cotransporters (pNBC1) allows influx of bicarbonates with sodium. Bicarbonates are exchanged for intraductal chloride by anion exchanger 1 (AE1) in the ApM. Activated CFTRs let some chloride to leak back to ducts, followed by water that dilutes ductal proteins. Replenished intraductal chloride allows more bicarbonate secretion. In CF patients, pancreatic water and bicarbonate secretion is limited by the intraductal chloride pool.
Related Concept Videos
Cystic Fibrosis: Pathogenesis
CF is primarily caused by a genetic mutation in a chromosome 7 gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The most common gene mutation leading to CF is the ΔF508 mutation,...
Cystic Fibrosis: Management
Sinus disease and chronic...
The Significance of Membrane Transport
Transporters facilitate either an active or passive movement of solutes. They can allow a single-molecule transport down its...
Mechanisms of Membrane-bending
Membrane bending can happen due to intrinsic changes in lipid composition or extrinsic association with different proteins. The proteins involved...
Transcellular Transport of Solutes

