SERUM CONCENTRATION OF THE PYRIDINOLINE CROSS-LINKED CARBOXYTERMINAL TELOPEPTIDE OF TYPE-I COLLAGEN (ICTP) IS A USEFUL INDICATOR OF DECLINEAND RECOVERY OF BONE-MINERAL DENSITY IN LUMBAR SPINE - ANALYSIS IN JAPANESE POSTMENOPAUSAL WOMEN WITH OR WITHOUT HORMONE REPLACEMENT

To reassess the clinical utility of serum pyridinoline cross-linked ca rboxyterminal telopeptide of type I collagen (ICTP), a promising but c ontroversial indicator of bone resorption, we evaluated its performanc e as a biochemical marker in a 6-month study of a strictly selected po pulation of 76 Japanese postmenopausal and healthy women, 33 recipient s of hormone replacement therapy and 43 nonrecipients. We measured bon e mineral density (BMD) of the lumbar spine (L-2-L-4), and serum ICTP, carboxyterminal propeptide of type I procollagen (PICP) and other con ventional serum biochemical markers, e.g. bone gla protein (BGP), alka line phosphatase, calcium and phosphate at the entry and 6 months late r. We calculated the percent change between the baseline and 6-month v alues (Delta%) in lumbar BMD and the biochemical markers, individually , and compared the degree of correlations between Delta% in BMD and th at in the biochemical markers. Delta% in ICTP and Delta% in BGP correl ated with Delta% in BMD negatively and significantly. Especially Delta % in ICTP correlated with that in BMD to a high degree (P<0.0001). No significant correlation was observed in other biochemical markers. We concluded that serum ICTP is a sensitive and useful bone resorption ma rker in the postmenopausal population, which strongly correlates with the change in BMD.