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Implementing Patch Clamp and Live Fluorescence Microscopy to Monitor Functional Properties of Freshly Isolated PKD Epithelium
Published on: September 1, 2015
In vitro fluid secretion by epithelium from polycystic kidneys
J J Grantham1, M Ye, V H Gattone
1Department of Medicine, Kansas University Medical Center, Kansas City 66160.
The Journal of Clinical Investigation
|January 1, 1995
Summary
Autosomal dominant polycystic kidney disease (ADPKD) kidney cyst growth is due to fluid accumulation. ADPKD cells can absorb or secrete fluid, with cAMP-mediated secretion potentially driven by anion transport.
Area of Science:
- Nephrology
- Cell Biology
- Molecular Physiology
Background:
- Autosomal dominant polycystic kidney disease (ADPKD) is characterized by kidney enlargement due to fluid-filled cysts.
- Understanding the mechanisms of cyst fluid secretion is crucial for ADPKD research.
Purpose of the Study:
- To investigate the transepithelial fluid movement in isolated human ADPKD kidney cysts and cultured ADPKD epithelial cells.
- To determine the role of cyclic AMP (cAMP) and ion transport in ADPKD cyst fluid secretion.
Main Methods:
- Measurement of net transepithelial liquid movement in isolated ADPKD cysts and cultured ADPKD monolayers.
- Stimulation with forskolin (cAMP activator) and ouabain (Na+/K+-ATPase inhibitor).
- Measurement of intracellular cAMP levels, transepithelial electrical potential difference (PDte), short-circuit current (SCC), and tissue resistance (Rte).
Main Results:
- Forskolin stimulated fluid secretion in excised ADPKD cysts.
- Cultured ADPKD monolayers showed both fluid absorption and secretion, with forskolin inducing secretion.
- Ouabain inhibited fluid secretion when present in the basolateral medium, suggesting active solute transport.
- Forskolin increased intracellular cAMP and SCC, while decreasing Rte, indicating active fluid transport pathways.
Conclusions:
- ADPKD cells in surface cysts possess the capacity for both fluid absorption and secretion.
- cAMP-mediated fluid secretion into ADPKD cysts may be driven by anion transport across the basolateral membrane.
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