Attenuation of calcific aortic valve disease by sortilin blockade in a preclinical minipig model

Abstract Introduction Calcific aortic valve disease (CAVD) is a progressive, life-threatening condition characterized by aortic stenosis and subsequent heart failure. Emerging evidence highlights the crucial role of oxidative stress in CAVD pathogenesis by promoting damage to the aortic valve's endothelium. Our previous work suggested that sortilin orchestrates a complex intracellular signaling pathway leading to endothelial dysfunction through increased reactive oxygen species (ROS) production in mice. Purpose To elucidate the molecular mechanisms by which sortilin links endothelial injury and oxidative stress to the progression of CAVD, and to evaluate the therapeutic potential of its inhibition. Methods Molecular mechanisms in vitro were investigated using isolated human valve endothelial cells. To assess the effects in vivo, Göttingen minipigs were randomly assigned to either a standard diet (SD) or a high-fat and cholesterol diet (HF) for 20 weeks. During this period, animals received either a placebo or the sortilin inhibitor AF38469 orally. Blood samples were collected periodically to analyze biochemical and oxidative stress markers. Aortic valve cusps were analyzed for cellularity, collagen, fibrosis, and calcification using histology. Immunohistochemistry and Western blotting were used to assess oxidative stress and osteoblast markers. Vascular reactivity studies were performed on isolated resistance vessels to evaluate endothelial function. Results The HF diet severely compromised endothelial integrity on the aortic valve surface, which was preserved by sortilin inhibition. Furthermore, the HF diet group showed increased levels of oxidative stress, activation of myofibroblast/osteoblast phenotypes, and mineralization within the valve—all of which were significantly reduced by the sortilin inhibitor AF38469. Notably, AF38469 also prevented the increases in plasma cholesterol and triglycerides as well as the endothelial dysfunction observed in the placebo-treated HF diet group. Conclusions Our data establish that sortilin negatively regulates valvular degeneration by driving the destruction of endothelial integrity, and promoting inflammation and oxidative stress. These findings underscore the critical role of the sortilin pathway in CAVD progression, highlighting sortilin inhibition as a promising novel therapeutic strategy for this disease.