Klein J R, Grunewald R W, Steffgen J, Franz H E
Department of Nephrology, University of Ulm, FRG.
Adv Perit Dial. 1991;7:225-9.
Osteocalcin (OC) is a bone-specific protein whose blood concentration is a specific and sensitive marker of bone turnover. In adults undergoing continuous ambulatory peritoneal dialysis (CAPD), mean serum osteocalcin levels (S-OC) are lower than in similar patients on hemodialysis. We therefore measured the serum (S) and dialysate (D) levels of OC, estimated the peritoneal clearance (Cp) and mass transfer (MT) of OC and evaluated the relationship between S-OC levels and other serum biochemical parameters of bone metabolisms. Fourteen adult patients on CAPD were studied with a mean age of 46.3 +/- 13 years and a mean dialytic age on CAPD of 17.4 +/- 9.6 months. OC concentrations in (S) and (D) were 60.8 +/- 55.5 micrograms/l (normal range: 4.3-12.4 micrograms/l) and 6.9 +/- 6.2 micrograms/l, respectively. The Cp of OC was 1.08 +/- 0.3 ml/min and the MT of OC over 4-h dialysis exchange periods was 14.5 +/- 12.3 micrograms when using a dialysis solution containing 2.27% glucose. S-OC was significantly correlated with serum levels of alkaline phosphatase (r = 0.80), intact PTH (r = 0.82) and the MT of OC (r = 0.94). No significant correlations were found with serum levels of total calcium, phosphate, creatinine, total protein and dialytic age. These results suggest that the OC level in serum is influenced by both bone turnover and peritoneal clearance. Therefore, altered serum levels of OC should be interpreted always together with the peritoneal mass transfer of OC. Taking this into account, OC and intact PTH may be of value as markers of increased bone turnover secondary to renal osteodystrophy in CAPD.
骨钙素（OC）是一种骨特异性蛋白，其血液浓度是骨转换的特异性和敏感标志物。在接受持续性非卧床腹膜透析（CAPD）的成年人中，血清骨钙素水平（S-OC）均值低于接受血液透析的类似患者。因此，我们测量了OC的血清（S）和透析液（D）水平，估算了OC的腹膜清除率（Cp）和物质转运（MT），并评估了S-OC水平与骨代谢其他血清生化参数之间的关系。对14例接受CAPD的成年患者进行了研究，其平均年龄为46.3±13岁，平均腹膜透析龄为17.4±9.6个月。S和D中的OC浓度分别为60.8±55.5微克/升（正常范围：4.3 - 12.4微克/升）和6.9±6.2微克/升。使用含2.27%葡萄糖的透析液时，OC的Cp为1.08±0.3毫升/分钟，4小时透析交换期内OC的MT为14.5±12.3微克。S-OC与血清碱性磷酸酶水平（r = = 0.80）、完整甲状旁腺激素（r = 0.82）以及OC的MT（r = 0.94）显著相关。与血清总钙、磷、肌酐、总蛋白水平及透析龄未发现显著相关性。这些结果表明，血清OC水平受骨转换和腹膜清除率两者影响。因此，血清OC水平的改变应始终结合OC的腹膜物质转运来解释。考虑到这一点，OC和完整甲状旁腺激素可能作为CAPD中肾性骨营养不良继发骨转换增加的标志物具有价值。
