CTSB and metabolic syndrome: This protein acts as a negative regulator of pro-atherogenic cysteine proteases [124] and is considered as a potential sensitive biomarker of changes in glomerular filtration in the kidneys, SVDs, and MetS [5,125,126,127,128], because cys-C is a powerful inhibitor of cysteine protease, which plays a pleiotropic role in the pathophysiology of human vessels.