COMP and osteoarthritis: Interestingly, cartilage oligomeric matrix protein (COMP, thrombospondin 5) was significantly down regulated in VO-OVX-VD3 as compared to VO-OVX, but not statistically different from the level in VO-SH animals, elevated COMP levels in serum being found to be predictive of developing joint destruction in osteoarthritis (RO-SH: 1.00±0.10; RO-OVX: 1.32±0.15; RO-OVX-VD3∶1.42±0.10; VO-SH: 1.06±0.09; VO-OVX: 1.26±0.07; VO-OVX-VD3∶0.79±0.09; p = 0.0003; ANOVA in the 6 groups).