Department of Nephrology, The Royal Melbourne Hospital, Parkville, Victoria, Australia.
Department of Medicine (RMH), University of Melbourne, Parkville, Victoria, Australia.
Am J Nephrol. 2018;47(6):376-384. doi: 10.1159/000489671. Epub 2018 May 23.
Cortical bone is a significant determinant of bone strength and its deterioration contributes to bone fragility. Thin cortices and increased cortical porosity have been noted in patients with chronic kidney disease (CKD), but the "Turnover Mineralization Volume" classification of renal osteodystrophy does not emphasize cortical bone as a key parameter. We aimed to assess trabecular and cortical bone microarchitecture by histomorphometry and micro-CT in patients with CKD G5 and 5D (dialysis).
Transiliac bone biopsies were performed in 14 patients undergoing kidney transplantation (n = 12) and parathyroidectomy (n = 2). Structural parameters were analysed by histomorphometry and micro-CT including trabecular bone volume, thickness (TbTh), number (TbN) and separation and cortical thickness (CtTh) and porosity (CtPo). Indices of bone remodelling and mineralisation were obtained and relationships to bone biomarkers examined. Associations were determined by Spearman's or Pearson's rank correlation coefficients.
By micro-CT, trabecular parameters were within normal ranges in most patients, but all patients showed very low CtTh (127 ± 44 µm) and high CtPo (60.3 ± 22.5%). CtPo was inversely related to TbN (r = -0.56; p = 0.03) by micro-CT and to TbTh (r = -0.60; p = 0.024) by histomorphometry and correlated to parathyroid hormone values (r = 0.62; p = 0.021). By histomorphometry, bone turnover was high in 50%, low in 21% and normal in 29%, while 36% showed abnormal patterns of mineralization. Significant positive associations were observed between osteoblast surface, osteoclast surface, mineralization surface and bone turnover markers.
Deterioration of cortical -microarchitecture despite predominantly normal trabecular parameters reinforces the importance of comprehensive cortical evaluation in patients with CKD.
皮质骨是骨强度的重要决定因素，其恶化导致骨脆性增加。在慢性肾脏病（CKD）患者中，已注意到皮质变薄和皮质孔隙率增加，但肾性骨营养不良的“转换矿化体积”分类并不强调皮质骨是关键参数。我们旨在通过组织形态计量学和微 CT 评估 CKD G5 和 5D（透析）患者的小梁和皮质骨微结构。
对 14 名接受肾移植（n=12）和甲状旁腺切除术（n=2）的患者进行了髂骨活检。通过组织形态计量学和微 CT 分析结构参数，包括小梁骨体积、厚度（TbTh）、数量（TbN）和分离以及皮质厚度（CtTh）和孔隙率（CtPo）。获得了骨重建和矿化指数，并检查了与骨生物标志物的关系。通过 Spearman 或 Pearson 等级相关系数确定相关性。
通过微 CT，大多数患者的小梁参数均在正常范围内，但所有患者的 CtTh（127±44µm）和 CtPo（60.3±22.5%）均非常低。CtPo 与微 CT 中的 TbN 呈负相关（r=-0.56；p=0.03）和组织形态计量学中的 TbTh 呈负相关（r=-0.60；p=0.024），并与甲状旁腺激素值相关（r=0.62；p=0.021）。通过组织形态计量学，50%的骨转换率高，21%的骨转换率低，29%的骨转换率正常，36%的骨转换率出现异常矿化模式。骨细胞表面、破骨细胞表面、矿化表面和骨转换标志物之间存在显著的正相关关系。
尽管小梁参数主要正常，但皮质微结构的恶化仍强调了在 CKD 患者中进行全面皮质评估的重要性。
