総説

腎病理から紐解く，CKD（慢性腎臓病）治療

髙野　秀樹

WAARM Journal, 2023; 5: 1–16

Key words：慢性腎臓病，老化，腎生検，低酸素，腎不全

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Abstract

  The kidneys are closely linked with the aging process, regulating homeostasis in the body and functioning as an endocrine organ. Chronic kidney disease is not only identified by the development of end-stage renal disease, but also by the high incidence of cardiovascular disease, which calls for urgent attention in preventive care. Determining the underlying cause of chronic kidney disease requires renal biopsy. Glomerular injury results in abnormal urine findings, while tubulointerstitial injury causes renal dysfunction. The nephron has a distinct architecture where blood vessels leaving the glomerulus return through the renal tubulointerstitium. Tubulointerstitial structure makes it susceptible to hypoxia, and reabsorption requires energy and significant oxygen consumption. Prevention of atherosclerosis has been the central focus in treating chronic kidney disease. With the advent of modern agents, it is critical to consider renal histology to manage the progression of the final common pathway of renal failure.

Key words:  慢性腎臓病，老化，腎生検，低酸素，腎不全

はじめに

　腎臓と老化には密接な関係がある．そこには，リン（P）の代謝排泄が大きく関与する．
　P の過剰摂取，高 P 血症は血圧上昇などにも繋がり，動脈硬化に関与すると言われる．通常は血清P が上昇する以前に Fibroblast Growth Factor-23（FGF23）が出現し，腎からの P の再吸収を抑制し，P 排泄を促進する．この FGF-23 から指令を受ける受容体が，Klotho 蛋白といわれ，そのほとんどは腎に局在している．この蛋白質をノックアウトした動物モデルでは，P の排泄が上手くできず，動脈石灰化や骨粗鬆症，皮膚の萎縮などいわゆる“早老”の症状を呈する．CKD では，腎機能が低下してくると，リン（P）の蓄積が起こり，同様に動脈硬化が促進しており，骨代謝の障害が起こる．即ち，腎臓を守ることは，老化の進行抑制することに繋がる．