IntroductionAortic valve stenosis (AVS) is a complex disease, characterized by the thickening of the aortic valve with significant fibrosis and/or calcification [1]. Short-term symptoms include shortness of breath and fainting, while more long-term symptoms include heart failure and inevitably, death [2]. Treatment for AVS remains non-existent, with surgical intervention being the only viable option for at-risk patients. Thus, there has been interest in finding innovative approaches to treating this perilous disease [3,4].The pathogenesis of AVS is an active process involving multiple cell types and complexed underlying mechanisms [5,6]. Upon differentiation of mesenchymal-like cells to chondrogenic cells, matrix vesicles are released, containing enzymes and other factors that lead to the onset of calcification [7]. One of these enzymes, alkaline phosphatase (ALP), is a metalloenzyme that has been shown to play a profound role in calcification onset by concentrating calcium [8], mineralizing hydroxyapatite crystals [8], and inactivating inhibitory polyphosphates [9]. In humans, there are four ALP isozymes: alkaline phosphatase, tissue-nonspecific isozyme (TNALP), intestinal-type alkaline phosphatase, placental-type alkaline phosphatase, and placental-like alkaline phosphatase [10]. Two isoforms of TNALP exist: bone-specific TNALP and liver-specific TNALP, both of which are abundantly found in the serum [10]. Within the context of vascular calcification, bone TNALP is highly expressed in calcifying vascular smooth muscle cells and is likely to be responsible for calcium deposition and AVS pathogenesis [10].A multitude of studies draw conclusions regarding the pathogenesis of AVS in humans by utilizing aortic valve interstitial cells from bovine [11][12][13]. The ultimate goal of these studies is to identify mechanisms that will help us better understand calcification onset in humans. However, there is a need to directly compare these animal models to humans and assess whether or not it is plausible to make such a
AbstractAortic valve stenosis (AVS) is one of the most common heart valve diseases, and surgical intervention remains the only viable treatment option. Thus, there is a need for novel and innovative treatments. One approach is to study the biological pathogenesis of this disease in hopes of finding new targets for drug therapy. Although this may be a viable option, it faces some methodological concerns. Many studies attempted to address the underlying mechanisms of this disease using aortic valves from bovine models. Although these may be viable models in certain diseased conditions, this may not be the case when studying calcification in AVS. Thus, the aim of our study was to assess the significance of drawing conclusions from bovine models to humans in the context of AVS, and investigate the role of alkaline phosphatase (ALP), an enzyme that increases calcium mineralization and deposition in aortic valve calcification. We also wanted to identify any differences in calcification when using different os...