ACAN and intervertebral disk degenerative disorder: As IDD progresses, the anabolism of extracellular matrix (ECM) components, including aggrecan (ACAN) and type II collagen (COL2A1), is suppressed, whereas the catabolism of ECM components, such as a disintegrin-like and metalloprotease with thrombospondin type-1 motif (ADAMTSs) and matrix metalloproteinases (MMPs), is increased in nucleus pulposus (NP)6.