Urinary γ-glutamyltransferase (GGT) as a potential marker of bone resorption
- 作者：Yutaro Asaba ; Kiyoshi Hiramatsu ; Yasumoto Matsui ; Atsushi Harada ; Yuji Nimura ; Nobuyoshi Katagiri ; Toshihiro Kobayashi ; Tsuyoshi Takewaka ; Masako Ito ; Shumpei Niida ; et al.
- 关键词：Osteoclast ; Bone resorption ; GGT
- 刊名：Bone
- 出版年：2006
- 期刊代码：39_87563282
- 类别：med
- 出版时间：December 2006
- 卷：39
- 期：6
- 页码：1276-1282
- 文件大小：658 K
摘要
We recently identified γ-glutamyltransferase (GGT) as a novel bone-resorbing factor. The present study was undertaken to determine whether GGT is a marker of bone resorption in two genetic models of hyper- and hypo-function of osteoclasts, as well as in postmenopausal women with accelerated bone resorption, using type I collagen N-telopeptide (NTX) and deoxypyridinoline (DPD) as established biochemical markers. Urinary excretion of GGT, corrected for creatinine, was found to be increased in osteoprotegerin (OPG)-deficient osteoporotic mice as well as in patients with postmenopausal osteoporosis (67–83 years of age); in both cases the urinary level decreased after treatment of patients or mice with alendronate, a selective inhibitor of bone resorption, concomitantly with a reduction in DPD and NTX. Conversely, in osteopetrotic op/op mice, urinary GGT increased in parallel with DPD after induction of osteoclasts with M-CSF injection. Constant infusion of parathyroid hormone (PTH) also increased urinary GGT along with DPD. In a survey of 551 postmenopausal women (50–89 years of age) at their regular health checkup, urinary GGT excretion exhibited a high correlation with DPD (ρ = 0.49, p < 0.0001). The calculated sensitivity and specificity for diagnosing elevated bone resorption, as determined by a DPD value higher than 7.6 nM/mM Cr, were 61%and 92%, respectively, when a cut-off value of 40 IU/g Cr was assigned for urinary GGT. Since GGT activity can be measured inexpensively in large numbers in a very short time, the measurement of urinary level may provide a convenient and useful method for mass screening to identify those with increased bone turnover and hence at increased risk for bone fracture.