Expression of Osteoprotegerin and Soluble Receptor Activator of Nuclear Factor Kappa B Ligand in the Aortic Valve Calcification

The mechanism of valve calcification, representing the main cause of aortic stenosis (AS) formation and progression still remains unclear. Currently, the role of the OPG/RANKL/RANK system is considered as one of important variants of valve calcification pathogenesis. In this study we have investigated the differences in the levels of OPG and sRANKL involved in the calcification processes in tissues of patients with severe AS. The study was performed on AS patients, on patients with aortic dilatation, and also on AS patients with aortic dilatation. Increased level of RANKL was found in AS patients and it was higher in valve than in aortic tissue. In patients with aortic dilatation the RANKL level negatively correlated with aortic dilatation. The results of this study confirm importance of the OPG/RANKL/RANK system for calcification in AS patients. Although patients of all groups had comparable values of OPG (including patients with aortic dilatation), increased RANKL level was found only in AS patients. This suggests involvement of some additional mechanisms influencing the increase of RANKL expression.