Physiological concept for a blood based CFTR test.
We tested the hypothesis that the cystic fibrosis transmembrane conductance regulator (CFTR) could be involved in the volume regulation of human red blood cells (RBC). Experiments were based on two gadolinium (Gd(3+)) sensitive mechanisms, i.e. inhibition of ATP release (thetaATP(i)) and membrane destabilization. RBC of either cystic fibrosis (CF) patients or healthy donors (non-CF) were exposed to KCl buffer containing Gd(3+). A significantly larger quantity of non-CF RBC (2.55 %) hemolyzed as compared to CF RBC (0.89 %). It was found that both of the Gd(3+) mechanisms simultaneously are needed to achieve hemolysis, since either overriding thetaATP(i) by exogenous ATP addition prevented Gd(3+) induced hemolysis, or mimicking thetaATP(i) by apyrase in absence of Gd(3+) could not trigger hemolysis. Additionally, ion driven volume uptake was found to be a prerequisite for Gd3+ induced hemolysis as chloride and potassium channel blockers reduced the Gd(3+) response. The results show that in non-CF RBC Gd(3+) exerts its dual effect leading to hemolysis. On the contrary, in CF RBC, lacking CFTR dependent ATP release, the sole Gd(3+) effect of membrane destabilization is not sufficient to induce hemolysis similar to non-CF. This concept could form the basis of a novel method suitable for testing CFTR function in a blood sample.
Institute of Physiology II, University of Muenster, Germany. schille@uni-muenster.de
Astrid
A
Stumpf
Kerstin
K
Wenners-Epping
Mike
M
Wälte
Tobias
T
Lange
Hans-Georg
HG
Koch
Johannes
J
Häberle
Angelika
A
Dübbers
Sabine
S
Falk
Ludwig
L
Kiesel
Dessy
D
Nikova
Reimer
R
Bruns
Helga
H
Bertram
Hans
H
Oberleithner
Hermann
H
Schillers
D000255:Adenosine Triphosphate / Q000097:blood; D000328:Adult; D016022:Case-Control Studies; D003550:Cystic Fibrosis / Q000097:blood* / Q000175:diagnosis / Q000235:genetics; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000097:blood* / Q000235:genetics; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism; D005682:Gadolinium / Q000494:pharmacology; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D007231:Infant, Newborn; D018625:Microscopy, Atomic Force; D009996:Osmotic Fragility / Q000187:drug effects
D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D000255:Adenosine Triphosphate; D005682:Gadolinium