Expression and Localization of Granzymes and Perforin in Human Calcific Aortic Valve Disease.

Background and aim of the study: Calcified aortic valve disease (CAVD) is an actively regulated disease that shares pathophysiological hallmarks with atherosclerosis. One of these common features is extracellular matrix (ECM) remodeling, which consists of a dynamic degradation and deposition of the ECM composition. Granzymes (Grs) are ECM degrading and pro-apoptotic proteases that have been detected in atherosclerotic lesions, but their role in CAVD remains unknown. Methods: The expression of granzymes and perforin was characterized in heavily stenotic valves (n = 20) and control valves (n = 6) using quantitative RT-PCR and immunohistochemistry. Results: Quantitative RT-PCR revealed that levels of granzymes A, B, H, K and M mRNA were 4.9-fold (p <0.001), 7.1-fold (p <0.001), 4.6-fold (p <0.001), 4.7-fold (p <0.001) and 2.8-fold (p = 0.069) higher, respectively, in stenotic aortic valves than in control valves. Perforin mRNA levels were 3.6-fold (p <0.001) higher in stenotic valves than in control valves. Granzyme A immunohistochemical positivity was observed in mast cells and lymphocytes, granzyme H in mast cells but not in lymphocytes, and granzyme K in lymphocytes but not in mast cells. A statistical analysis was also performed to investigate the effect of statin treatment on granzyme expression, but no differences were found when compared to non-statin-treated patients. Conclusions: The data acquired showed that CAVD is characterized by an increased expression of granzymes A, B, H, K, and perforin.