Hypertension and congenital aortic valve malformations are frequent causes of ascending aortic aneurysms. The molecular
mechanisms of aneurysm formation under these circumstances are not well understood. Reference genes for gene activity
studies in aortic tissue that are not influenced by aortic valve morphology and its hemodynamic consequences, aortic
dilatation, hypertension, or antihypertensive medication are not available so far. This study determines genes in ascending
aortic tissue that are independent of these parameters. Tissue specimens from dilated and undilated ascending aortas were
obtained from 60 patients (age #70 years) with different morphologies of the aortic valve (tricuspid undilated n = 24,
dilated n = 11; bicuspid undilated n = 6, dilated n = 15; unicuspid dilated n = 4). Of the studied individuals, 36 had
hypertension, and 31 received ACE inhibitors or AT1 receptor antagonists. The specimens were obtained intraoperatively
from the wall of the ascending aorta. We analyzed the expression levels of 32 candidate reference genes by quantitative RTPCR (RT-qPCR). Differential expression levels were assessed by parametric statistics. The expression analysis of these 32
genes by RT-qPCR showed that EIF2B1, ELF1, and PPIA remained constant in their expression levels in the different
specimen groups, thus being insensitive to aortic valve morphology, aortic dilatation, hypertension, and medication with
ACE inhibitors or AT1 receptor antagonists. Unlike many other commonly used reference genes, the genes EIF2B1, ELF1, and
PPIA are neither confounded by aortic comorbidities nor by antihypertensive medication and therefore are most suitable for
gene expression analysis of ascending aortic tissue.
