Okabe R, Nakatsuka K, Inaba M, Miki T, Naka H, Masaki H, Moriguchi A, Nishizawa Y
Department of Metabolism, Endocrinology and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan.
Clin Chem. 2001 Aug;47(8):1410-4.
The Elecsys beta-CrossLaps serum assay measures type I collagen degradation fragments (beta-CTx) that contain the beta-isomerized octapeptide EKAHD-beta-GGR. We investigated the analytical performance of the assay and changes in beta-CrossLaps in patients with metabolic bone diseases.
The electrochemiluminescent sandwich immunoassay uses two monoclonal antibodies directed against different regions of the linear EKAHD-beta-GGR.
beta-CrossLaps (beta-CTx) immunoreactivity was stable in serum and plasma stored at 4 degrees C for 24 h or at room temperature for 4 h, and it did not decrease appreciably in samples stored at -30 degrees C for 12 weeks. Nine cycles of repeated freezing-thawing did not affect serum beta-CTx. The intra- and interassay imprecision (CVs) for four samples was < or = 2.6% (n = 10) and < or = 4.1% (n = 10), respectively. The mean day-to-day biological variation (CV) was 20% in 10 postmenopausal women (n = 10 days). Serum beta-CTx and osteocalcin were correlated in patients with hyperparathyroidism (r = 0.796; P <0.0001; n = 28), chronic renal failure on hemodialysis (r = 0.784; P = 0.0003; n = 16), hypoparathyroidism (r = 0.950; P = 0.0001; n = 11), and pseudohypoparathyroidism (r = 0.987; P = 0.130; n = 4). Serum beta-CTx decreased by 47.4% +/- 8.8% (mean +/- SD) and 60.7% +/- 6.5% at 3 and 6 months, respectively, after initiation of estrogen replacement therapy in 34 women. These decreases were greater than the decreases in urinary excretion of deoxypyridinoline (31.8% +/- 3.9% and 38.1% +/- 4.4%, respectively) or pyridinoline cross-linked C-terminal telopeptide of type I collagen (15.9% +/- 3.9% and 16.9% +/- 4.6%, respectively).
The Elecsys beta-CrossLaps serum assay provides a potentially useful tool for assessing bone resorption state, including its response to estrogen replacement therapy.
罗氏电化学发光法检测血清β-交联C端肽可测定I型胶原降解片段（β-CTx），该片段包含β-异构化八肽EKAHD-β-GGR。我们研究了该检测方法的分析性能以及代谢性骨病患者β-交联C端肽的变化情况。
电化学发光夹心免疫分析法使用两种针对线性EKAHD-β-GGR不同区域的单克隆抗体。
β-交联C端肽（β-CTx）免疫反应性在4℃保存24小时或室温保存4小时的血清和血浆中稳定，在-30℃保存12周的样本中也无明显下降。9个循环的反复冻融不影响血清β-CTx。4个样本的批内和批间不精密度（CV）分别≤2.6%（n = 10）和≤4.1%（n = 10）。10名绝经后女性（n = 10天）的平均日间生物学变异（CV）为20%。在甲状旁腺功能亢进患者（r = 0.796；P <0.0001；n = 28）、血液透析的慢性肾衰竭患者（r = 0.784；P = 0.0003；n = 16）、甲状旁腺功能减退患者（r = 0.950；P = 0.0001；n = 11）和假性甲状旁腺功能减退患者（r = 0.987；P = 0.130；n = 4）中，血清β-CTx与骨钙素相关。34名女性开始雌激素替代治疗后3个月和6个月时，血清β-CTx分别下降了47.4%±8.8%和60.7%±6.5%。这些下降幅度大于脱氧吡啶啉尿排泄量的下降幅度（分别为31.8%±3.9%和38.1%±4.4%）或I型胶原吡啶啉交联C端肽的下降幅度（分别为15.9%±3.9%和16.9%±4.6%）。
罗氏电化学发光法检测血清β-交联C端肽为评估骨吸收状态提供了一种潜在有用的工具，包括其对雌激素替代治疗的反应。
