MiRNA microarray analysis of human bicuspid and tricuspid aortic valve leaflet tissues

Bicuspid aortic valve (BAV) is a common congenital cardiac anomaly, with an estimated incidence of 1-2%. It is responsible for the greatest burden of aortic valve disease in patients younger than 70 years in North America. We performed microRNA profiling in end-stage valve leaflets with BAV and TAV. Patients undergoing elective aortic valve replacement for aortic stenosis at St. Michael’s Hospital, University of Toronto, between June 2010 and June 2011 were enrolled. Aortic valve leaflets were obtained intraoperatively from patients with congenital bicuspid (BAV; N=10) and tricuspid aortic valves (TAV; N=10) at the time of valve replacement. Leaflets were flash frozen in liquid nitrogen. MiRNA was isolated using the miRNeasy kit (Qiagen, Hilden, Germany) according to the manufacturer`s instructions. For miRNA microarray analysis, total RNA was directly labeled with biotin and hybridized to the GenoExplorer microRNA human array containing 1583 human miRNA probes (Genosensor, Tempe, AZ) and the fluorescent signals were then scanned using a GenePix 4000b Biochip. The average of 3 mean fluorescence signal intensities for each miRNA probe was normalized to that for tRNAmet. Precursor miRNAs detected at 2-fold greater than background were considered to be expressed. Data were analyzed with GenePix 5.0 software, provided by GenoSensor Corp.