| 特集名 | 透析診療における分子バイオマーカーの新たな展開 | |
|---|---|---|
| 題名 | ［各論― 日常透析診療に役立つ分子バイオマーカー］骨・ミネラル代謝異常 | |
| 発刊年月 | 2011年 04月 | |
| 著者 | 小岩 文彦 | 昭和大学藤が丘病院腎臓内科 |
| 著者 | 丸田 雄一 | 昭和大学藤が丘病院腎臓内科 |
| 【 要旨 】 | 慢性腎臓病（CKD）に合併した骨ミネラル代謝異常（CKD-MBD）に伴う骨病変の診断は骨生検で行うのが望ましいが，骨折リスクに影響する骨塩量の変化や骨回転を簡便に検査可能な骨代謝マーカーが代用指標となる．しかし，腎機能障害の影響を受ける項目もあり，注意して判断する必要がある． fetuin-Aは循環血中の過剰なミネラルと結合，あるいは複合体を形成して石灰化を抑制し，石灰化抑制に寄与する．腎不全でfetuin-Aは低下するが，血中濃度と石灰化との関連は不明である．FGF 23は腎臓に作用してリン（P）利尿とビタミンD合成を抑制する．早期腎障害から血中濃度は上昇し，二次性副甲状腺機能亢進症の発症に関与する．さらにCKDのP代謝異常，腎機能低下予測，心血管病，予後に関与し，その度合いは血清P値より大きく，新たなCKD-MBD関連バイオマーカーとして注目されている． |
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| Theme | New Perspectives of Molecular Biomarker in Dialysis Therapy | |
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| Title | Biomarkers of bone and mineral metabolic disorders | |
| Author | Fumihiko Koiwa | Division of Nephrology, Department of Internal Medicine, Showa University Fujigaoka Hospital |
| Author | Yuichi Maruta | Division of Nephrology, Department of Internal Medicine, Showa University Fujigaoka Hospital |
| [ Summary ] | Although the standardized diagnostic method for determining bone disease in CKD-MBD patients is bone biopsy, measurement of serum bone metabolic markers can be readily evaluated to determine changes in bone mineral density or bone turnover. It should be kept in mind that there are some bone markers, including serum levels, which are influenced by renal function. Fetuin A is an inhibitor of extraosseous calcification in supersaturated environments which operates through binding excess minerals or the fetuin-mineral complex. Serum fetuin A levels are reduced due to renal failure. However, the relationship between serum fetuin A levels and calcification have not been clarified even for cases of chronic renal failure. Fibroblast growth factor 23 (FGF 23) binds to the FGF receptor klotho complex in the kidneys, induces phosphaturia by decreasing phosphate reabsorption and decreases the synthesis of 1,25-dihydroxyvitamin D. Serum FGF 23 levels increase in early renal failure, leading to the onset and progression of secondary hyperparathyroidism. Moreover, FGF 23 is associated with various clinical outcomes, including phosphate metabolic disorder, progression of renal failure, cardiovascular disease, and mortality. The detectability of these outcomes is higher when using serum phosphate levels as a biomarker. |
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