part of part of has part has part characteristic of inheres in has modifier Pyridinoline Abnormal circulating collagen degradation product concentration Elevated circulating pyridinoline concentration 2021-01-02T13:36:47Z An increased concentration of hydroxylysyl-pyridinoline (pyridinoline) in the blood circulation. The urinary cross-links lysyl-pyridinoline (LP, or deoxypyridinoline DPD) and hydroxylysyl-pyridinoline (HP, or pyridinoline PYD) are established biochemical markers of osteoclastic bone resorption and collagen degradation. Pyridinolines are formed during fibril formation of type I and type II collagen in the extracellular matrix. Some lysyl- and hydroxylysyl-residues in distinct positions in the collagen triple-helix and in the telopeptides of the tropocollagen are oxidized by lysyl oxidase. Subsequently three of these residues are covalently linked thereby interconnecting tropocollagen molecules and stabilizing the collagen matrix. When bone collagen is degraded, pyridinolines remain as stable degradation products and are secreted with the urine. Depending on whether or not these lysyl residues had been hydroxylated prior to crosslinking, lysyl-pyridinoline (LP) or hydroxylysyl-pyridinoline (HP) is generated. abnormal increased amount blood