GRP and osteoarthritis: Gla-rich protein (GRP), also known as upper zone of growth plate and cartilage matrix associated protein (UCMA) [7,8], is a circulating vitamin K-dependent protein (VKDP) shown to execute important functions in multiple processes associated with the development of CIDs, such as CVD, osteoarthritis, rheumatoid arthritis, and CKD [9,10,11,12,13,14], and has recently been proposed as a biomarker for vascular and valvular calcification (VC) and kidney dysfunction [15,16].