Abstract 14542: Impact of MicroRNA Expression in Human Atrial Tissue For Patients With Atrial Fibrillation Undergoing Open Heart Surgery
BACKGROUND Although microRNA (miR) was shown to regulate initiation and/or progression of atrial fibrillation (AF) in a canine AF model, underling mechanism in human tissue and its clinical impact are still unclear. We hypothesized that certain miRs in atrial tissue may be related to AF occurrence, suggesting there use as biomarkers in cardiac surgery for its management. This study sought to evaluate the relationship between miR expression in human atrial tissue with AF after cardiac surgery and MAZE procedure outcomes.
METHODS Right atrial tissues were obtained from 26 patients undergoing open heart surgery, who were divided into four groups (Group A: chronic AF or unsuccessful MAZE procedure, n=5; Group B: successful MAZE procedure, n=8; Group C: sinus rhythm (SR) and postoperative AF, n=3; Group D: preoperative SR without postoperative AF, n=10). MiR expression was determined using high density microarray-and those highly-expressed were assessed with real-time PCR. Fibrosis in each atrial tissue specimen was examined with Masson trichrome staining.
RESULTS (1) MiR microarray analysis showed that miR 21, 23b, 199b, and 208b were elevated in the preoperative AF group (A+B) as compared to the preoperative SR group (C+D). (2) Real-time PCR showed high expressions of miR 21 (2.2-fold) and 208b (4.4-fold) in the AF group as compared to the SR group. (3) In altered expression profiles of miRs in each group (A,B,C) relative to group D, miR 21 expression was increased from Group C to A (A: 2.8-fold, B:2.4-fold, C: 1.7-fold). (4) Fibrosis was increased from group D to A (A: 44.2±14.6%, B: 22.3±5.8%, C: 14.7±2.4%, D:11.2±2.9%). There was a correlation between percent fibrosis and miR 21 expression (r=0.508, p<0.05).
CONCLUSIONS In conclusion, miR 21 and 208b expressions in human atrial tissue are related to AF occurrence. The degree of miR 21 expression may predict MAZE procedure outcome and postoperative AF occurrence in patients undergoing cardiac surgery with preoperative SR.
- © 2011 by American Heart Association, Inc.