Fong Debra, Denton Kate M, Moritz Karen M, Evans Roger, Singh Reetu R
Department of Physiology, Monash University, Clayton, Victoria, Australia.
Nephrology (Carlton). 2014 Mar;19(3):119-28. doi: 10.1111/nep.12198.
Compensatory renal growth is a characteristic adaptation to reduced renal mass that appears to recapitulate the normal pattern of maturation of the kidney during the postnatal period. Hypertrophy of tubules (predominantly the proximal tubule) and glomeruli is accompanied by increased single nephron glomerular filtration rate and tubular reabsorption of sodium. We propose that the very factors, which contribute to the increase in growth and function of the renal tubular system, are, in the long term, the precursors to the development of hypertension in those with a nephron deficit. The increase in single nephron glomerular filtration rate is dependent on multiple factors, including reduced renal vascular resistance associated with an increased influence of nitric oxide, and a rightward shift in the tubuloglomerular feedback curve, both of which contribute to the normal maturation of renal function. The increased influence of nitric oxide appears to contribute to the reduction in tubuloglomerular feedback sensitivity and facilitate the initial increase in glomerular filtration rate. The increased single-nephron filtered load associated with nephron deficiency may promote hypertrophy of the proximal tubule and so increased reabsorption of sodium, and thus a rightward shift in the pressure natriuresis relationship. Normalization of sodium balance can then only occur at the expense of chronically increased arterial pressure. Therefore, alterations/adaptations in tubules and glomeruli in response to nephron deficiency may increase the risk of hypertension and renal disease in the long-term.
肾代偿性生长是对肾单位减少的一种特征性适应，似乎重现了出生后肾脏正常的成熟模式。肾小管（主要是近端小管）和肾小球的肥大伴随着单个肾单位肾小球滤过率的增加和肾小管对钠的重吸收增加。我们提出，从长远来看，那些导致肾小管系统生长和功能增加的因素正是肾单位不足者发生高血压的先兆。单个肾单位肾小球滤过率的增加取决于多种因素，包括与一氧化氮影响增加相关的肾血管阻力降低，以及肾小管-肾小球反馈曲线的右移，这两者都有助于肾功能的正常成熟。一氧化氮影响的增加似乎有助于降低肾小管-肾小球反馈敏感性，并促进肾小球滤过率的初始增加。与肾单位不足相关的单个肾单位滤过负荷增加可能会促进近端小管的肥大，从而增加钠的重吸收，进而使压力-利钠关系右移。钠平衡的正常化只能以动脉压长期升高为代价。因此，长期来看，肾小管和肾小球对肾单位不足的改变/适应可能会增加高血压和肾脏疾病的风险。
