Cardiomyocyte progenitors in a canine pulmonary vein model of persistent atrial fibrillation.
BACKGROUND
This study aimed to discover the pathogenesis of focal atrial fibrillation (AF) originating from pulmonary veins by observing the histological structure and special cells in the canine pulmonary vein model of persistent atrial fibrillation.


METHODS
The pulmonary veins and the sinus node were obtained from 10 mongrel dogs (5 AF and 5 control group). Light microscopy, transmission electron microscopy, and immunohistochemistry were applied to transverse sections of each pulmonary vein and sinoatrial node. Morphological and distribution analyses were performed manually and automatically.


RESULTS
Cardiomyocyte progenitor (CMPs) and interstitial cells of Cajal (ICCs) showing typical features of either very immature or developing cells were found in the pulmonary vein sections of all animals subjected to experimental AF but not in the control group. The cells were mainly identified in sections with a thick muscular sleeve. A positive immunostaining of CMPs was also demonstrated; the staining characteristic was similar to that of P cells in the sinoatrial node, suggesting that these cells may function in a pacemaker capacity.


CONCLUSIONS
We demonstrated that pulmonary veins can host cardiac stem cell niches. Continuous rapid pacing can induce the differentiation of CMPs and ICCs, and CMPs may underlie the pacemaker activity of isolated pulmonary veins.
Department of Cardiology, Longgang District Central Hospital of Shenzhen, Guangdong, China.
Xian-zhi
XZ
He
Hai-yu
HY
Wang
Yan
Y
Shen
Qing-hua
QH
Zhong
Sheng-xian
SX
Fang
Wen-jun
WJ
Peng
Jian-fang
JF
Xue
D000818:Animals; D001281:Atrial Fibrillation / Q000473:pathology*; D002454:Cell Differentiation; D004285:Dogs; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D023421:Models, Animal; D032383:Myocytes, Cardiac / Q000473:pathology*; D011667:Pulmonary Veins / Q000473:pathology*; D012849:Sinoatrial Node / Q000473:pathology; D013234:Stem Cells / Q000473:pathology*