SPP1 and nephrolithiasis: Urolithiasis and CAD share a common pathogenesis as the process of renal calcification is similar to atherosclerotic calcification because the formation of subepithelial calcium phosphate deposits in renal papillary vessels provides the nidus for kidney stone formation and osteopontin, an important component in the urinary calcium stone matrix, is also an important factor for the development of atherosclerosis and CAD [44].