Correlation between atrial ZnT-1 expression and atrial fibrillation in humans: a pilot study.
BACKGROUND
Until recently, the membrane protein ZnT-1 was studied mainly in the context of zinc homeostasis. However, new findings indicate that it acts as an inhibitor of L-type calcium channels. We recently found that acute rapid pacing of the rat atria in vivo augments the expression of ZnT-1, while knockdown of ZnT-1 in culture can oppose the inhibition of L-type calcium channels following rapid pacing. This pilot study, the first to assess cardiac ZnT-1 in humans, was designed to look for possible correlation between the atrial expression of ZnT-1 and atrial fibrillation.


METHODS
Right atrial appendage tissue was collected from 39 patients (27 with sinus rhythm and 12 with atrial fibrillation; 6-permanent, 6- paroxysmal or persistent) undergoing open-heart surgery. The expression of ZnT-1 was analyzed by Western blot utilizing beta-actin as an internal loading control and a standard rat heart sample (STD) for inter-blot comparison.


RESULTS
Overall atrial fibrillation patients (n = 12) had median ZnT-1/beta-actin of 1.80 STD (inter-quartile range 1.26 to 2.85) versus 0.73 STD (0.24 to 1.64) in the sinus rhythm group (P = 0.002). No association was found between ZnT-1 level and most other clinical parameters tested. Multivariate analysis determined that atrial fibrillation and increased body mass index were the only independent variables clearly associated with higher ZnT-1 levels (Standardized coefficients Beta = 0.62, 0.31; P = 0.002, P = 0.04, respectively).


CONCLUSIONS
This pilot study provides evidence for increased ZnT-1 expression in the atria of patients with atrial fibrillation.
Etzion
Yoram
Y
Cardiac Arrhythmia Research Laboratory, Soroka University Medical Center, Beer-Sheva, Israel. tzion@bgu.ac.il
Ganiel
Amir
A
Beharier
Ofer
O
Shalev
Aryeh
A
Novack
Victor
V
Volvich
Liobov
L
Abrahamov
Dan
D
Matsa
Menachem
M
Sahar
Gideon
G
Moran
Arie
A
Katz
Amos
A
D000368:Aged; D001281:Atrial Fibrillation / Q000235:genetics* / Q000378:metabolism*; D027682:Cation Transport Proteins / Q000096:biosynthesis* / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D006325:Heart Atria / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects
D027682:Cation Transport Proteins; C498299:SLC30A1 protein, human