[Cutting edge on research of cartilage metabolism. Recent progress in bio-molecular imaging of articular cartilage].

In the process of cartilage degeneration seen in osteoarthritis, loss of proteoglycan from articular cartilage has been widely accepted as a critical early event, followed by collagen degradation designated as a point of no return. Recent advance in the development of targeted molecular probes and new imaging modalities enabled the detection of qualitative and functional change of articular cartilage. In this paper, we describe the recent progress of bio-molecular imaging of articular cartilage including our fluorescent-labeled glycosaminoglycan-binding octaarginine.