Abstract Body: Calcific aortic valve disease (CAVD) is the most common valvular heart disease worldwide, characterized by endothelial dysfunction, lipid accumulation, and inflammation, ultimately leading to calcification. We previously demonstrated that reduced integrin-linked kinase (ILK) expression in the aortic valve endothelium contributes to disease progression by promoting endothelial-to-osteoblastic differentiation. However, no biomarkers are currently available to detect endothelial ILK reduction.
We utilized a conditional endothelial ILK knockout murine model (ecILKcKO) to investigate aortic valve calcification and identify potential circulating microRNAs (miRNAs) as biomarkers for CAVD. ecILKcKO mice exhibited increased expression of calcification markers (OSX, OPN, RUNX2) at three weeks (p<0.05) and significant fibrosis and valve leaflet thickening (p<0.01). However, pronounced valve deterioration emerged at twelve weeks post-ILK deletion, with increased peak aortic valve velocity (p<0.0001) and calcium deposit formation. Following confirmation of CAVD development in this model, we conducted RNA sequencing to analyze circulating miRNAs and compared these findings with miRNA profiles from CAVD patients. Notably, miR-199a-3p and miR-26b-5p were significantly downregulated in both ecILKcKO mice and CAVD patients. Validation in twelve-week-old ecILKcKO mice confirmed decreased circulating miR-199a-3p (p<0.01) and miR-26b-5p (p<0.05), mirroring results in CAVD patients (n=60) versus non-CAVD controls (n=30) (p<0.05). ROC curve analysis revealed AUC>0.62 (p<0.05) for both miRNAs in human samples. Our findings suggest that circulating miR-199a-3p and miR-26b-5p are sensitive to endothelial ILK reduction and disease presence, positioning them as potential biomarkers for monitoring CAVD progression. The availability of the ecILKcKO model provides a valuable platform for further validation and mechanistic studies.