臨牀透析 Vol.13 No.1(8-8)


特集名 副甲状腺機能低下症
題名 慢性透析患者の副甲状腺機能低下症 (8) 腎不全に伴う副甲状腺機能異常の骨代謝マーカー
発刊年月 1997年 01月
著者 田畑 勉 蒼龍会井上病院内科
著者 西沢 良記 大阪市立大学医学部第二内科
【 要旨 】 腎性骨異栄養症(ROD)は骨組織学的所見より高回転型骨症である線維性骨炎と低回転型骨症に大別され,さらに低回転型骨症は無形成骨症と骨軟化症に分けられる.Torresらは透析患者における血中intact PTH濃度と骨組織所見の検討より血中intact PTHが120pg/ml以下では低回転型骨症を,300pg/ml以上では高回転型骨症を示す頻度が高く,120~300pg/mlでは骨代謝回転を正常に維持できると報告している.骨形成の際に合成・分泌される骨基質蛋白や,骨吸収に伴って血中に放出される骨基質代謝産物などの骨代謝マーカーを繰り返し測定することでRODの骨代謝状態が評価されている.血液透析患者において血中intact PTHよりみた副甲状腺機能低下症(120pg/ml以下)では,骨代謝マーカーである骨型ALP,オステオカルシン,TRAP,PICPはともに正常群(120~300pg/ml)に比較して有意な低値を示した.骨代謝マ一カ一の代謝排泄過程が十分解明されていないものも多く,健常者の血中濃度域が透析患者の至適濃度とは考えにくく,相対値の意義は認めるものの,PTHと同様に透析患者における骨代謝マーカーの目標とする絶対値の意義の検討が必要と思われる.
Theme Hypoparathyroidism and Related Problems in Dialysis Patients
Title Markers of bone metabolism in hypoparathyroidism with renal failure
Author Tsutomu Tabata Department of Internal Medicine, Inoue Hospital
Author Yoshiki Nishizawa Second Department of Internal Medicine, Osaka City University Medical School
[ Summary ] Renal osteodystrophy (ROD) is categorized into high turnover bone and low turnover bone according to bone histology. High turnover bone disease consists of ostitis fibrosa which is accompanied by secondary hyperparathyroidism (2° HPT) and mixed type of ostitis fibrosa and osteomalacia. Osteomalacia and adynamic bone result from low turnover of bone. In contrast to the focal assessment of disease by bone histology, biochemical markers provide an integrated assessment of the activity of ROD, which has been assessed in terms of caicium metabolism, collagen turnover, and indices of the functional activity of bone cells themselves. The patients with adynamic bone disease have lower plasma parathyroid hormone (PTH) level when compared to those with normal or high bone turnover. Therefore hypoparathyroidism is considered to be one of the responsible factors. Torres, et al. reported that plasma intact PTH levels below 120pg/ml was highly predictive of low bone turnover, and that the plasma PTH level above 300pg/ml was always associated with histologic features of ostitis fibrosa. So they concluded that PTH levels of 120 to 300pg/ml were required to avoid low bone turnover and ostitis in hemodialysis patients. In our hemodialysis patients who had plasma intact PTH below 120pg/ml the plasma levels of bone-ALP, osteocalcin, TRAP, and PICP were significantly lower than those in the patients who had PTH between 120 and 300pg/ml. Plasma levels of biochemical markers in healthy subjects are not thought to be the optimal levels of those in hemodialysis patients, because the precise matabolism and excretion of biochemical markers is not fully understood. Further studies are need in order to clarify the optimal levels of biochemical markers in hemodialysis patients.
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