title: [Biochemical markers of bone turnover. New aspect. Bone collagen metabolism: new biological markers for estimation of bone quality].
abstract: Collagen cross-links play important roles in the expression of bone strength and the proper biological function of bone. The cross-links of collagen can be roughly divided into two types : lysyl oxidase mediated cross-links (enzymatic immature and mature cross-links) and advanced glycation end-products (AGEs ; nonenzymatic cross-links, pentosidine) . Recently, we show that reduction in enzymatic cross-links and excessive formation of nonenzymatic crossl-links, pentosidine in bone could be important for explaining the variation of fracture susceptibility in osteoporosis (Osteoporos Int 17 (7) : 986-995, 2006) and diabetes (Osteoporos Int 17 (10) : 1514-1523, 2006) . We also demonstrate that urinary excretion AGEs cross-link, pentosidine is a novel risk for future vertebral fracture (J Bone Miner Metab 26 (1) : 93-100, 2008) . Such deteriorated cross-links in osteoporosis may be induced by moderately elevated homocysteine in sera (Osteoporos Int 2009 in press, Calcif Tissue Int 79 (3) : 160-168, 2006, J Bone Miner Metab 26 (6) : 595-602, 2008) . These results indicate that elevated serum or urine pentosidine and plasma homocysteine levels in osteoporosis and diabetes is useful marker for estimation of fracture risk independent of bone turnover and bone mineral density. In this review, I summarize the recent literatures regarding bone quality markers.
authors.affiliation: Department of Orthopaedic Surgery, Jikei University of Medicine.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Saito
mesh_terms: D001120:Arginine / Q000031:analogs & derivatives / Q000097:blood / Q000652:urine; D015415:Biomarkers / Q000097:blood / Q000652:urine; D015519:Bone Density; D016723:Bone Remodeling; D001862:Bone Resorption / Q000175:diagnosis*; D001842:Bone and Bones / Q000378:metabolism*; D003094:Collagen / Q000378:metabolism*; D017127:Glycation End Products, Advanced / Q000378:metabolism; D006710:Homocysteine / Q000097:blood; D006801:Humans; D008239:Lysine / Q000031:analogs & derivatives / Q000097:blood / Q000652:urine; D010024:Osteoporosis / Q000175:diagnosis* / Q000209:etiology; D018384:Oxidative Stress
chemical_list: D015415:Biomarkers; D017127:Glycation End Products, Advanced; D006710:Homocysteine; D003094:Collagen; D001120:Arginine; C062187:pentosidine; D008239:Lysine