De Santo N G, Anastasio P, Cirillo M, Spitali L, Capazzo G, Santoro D
Chair of Nephrology, Second University of Naples, Italy.
Nephrol Dial Transplant. 1995;10(9):1629-36.
The renal haemodynamic response to a meat meal is usually measured as either filtration capacity (maximal achieved GFR), or renal reserve (maximal GFR increase over baseline), or percent renal reserve (maximal GFR increase as a percentage of baseline). The time-course of GFR response to a meat meal varies in different individuals as the peak GFR tends to occur late in renal disease. This study proposes a new method to measure the GFR response independently of differences in peaking time.
The study is based on measurement of GFR (inulin clearance, ml/min x 1.73 m2 BSA) in three 30-min pre-meal clearance periods (baseline) followed by analysis of the GFR changes for up to 180 min (four 30-min and one 60-min clearance periods) after a meat meal (2 g of protein/kg of BW as red cooked meat). Data were analysed from 85 healthy people (GFR > or = 100) and 273 individuals with renal disease (RD) who were divided into three groups based on their baseline GFR (RD1, n = 115, GFR 99-66; RD2, n = 85, GFR 65-33; RD3, n = 73, GFR < 33).
In healthy people after the meat meal GFR peaked between 30 and 60 min and returned to baseline by 120 min. In the three RD groups GFR peaked later than in healthy people (P < 0.001) and remained higher than baseline for up to 180 min (P < 0.001). Cumulative post-meal GFR changes, calculated as cumulative GFR increase over baseline up to 120 min after meal (ml/120 min x 1.73 m2 BSA), were significantly different (P < 0.01) in the four groups (healthy people, 937 +/- 141; RD1, 1222 +/- 141; RD2, 587 +/- 104; RD3, 361 +/- 89). Interindividual variability in cumulative GFR increase was only partially explained by the value of filtration capacity (r2 = 0.285), renal reserve (r2 = 0.640), and percent renal reserve (r2 = 0.175).
The data indicate that commonly used parameters are poor indices of the actual total time-course of the renal response to a protein load.
对一顿肉食的肾血流动力学反应通常通过滤过能力（达到的最大肾小球滤过率）、肾储备（相对于基线的最大肾小球滤过率增加值）或肾储备百分比（相对于基线的最大肾小球滤过率增加值占基线的百分比）来衡量。由于肾小球滤过率对一顿肉食的反应时程在不同个体中有所不同，因为肾小球滤过率峰值在肾脏疾病中往往出现较晚。本研究提出了一种新的方法来测量肾小球滤过率反应，而不受峰值时间差异的影响。
该研究基于在三个餐前30分钟清除期（基线）测量肾小球滤过率（菊粉清除率，毫升/分钟×1.73平方米体表面积），然后分析一顿肉食（2克蛋白质/千克体重，红烧肉类）后长达180分钟（四个30分钟和一个60分钟清除期）的肾小球滤过率变化。对85名健康人（肾小球滤过率≥100）和273名肾病患者的数据进行了分析，这些肾病患者根据其基线肾小球滤过率分为三组（RD1，n = 115，肾小球滤过率99 - 66；RD2，n = 85，肾小球滤过率65 - 33；RD3，n = 73，肾小球滤过率< 33）。
在健康人中，肉食后肾小球滤过率在30至60分钟达到峰值，并在120分钟时恢复到基线。在三个肾病组中，肾小球滤过率峰值出现的时间比健康人晚（P < 0.001），并且在长达180分钟内一直高于基线（P < 0.001）。餐后肾小球滤过率的累积变化，计算为餐后120分钟内相对于基线的肾小球滤过率累积增加值（毫升/120分钟×1.73平方米体表面积），在四组中差异显著（P < 0.01）（健康人，937 ± 141；RD1，1222 ± 141；RD2，587 ± 104；RD3，361 ± 89）。肾小球滤过率累积增加值的个体间变异性仅部分由滤过能力值（r2 = 0.285）、肾储备（r2 = 0.640）和肾储备百分比（r2 = 0.175）解释。
数据表明，常用参数不能很好地反映肾脏对蛋白质负荷反应的实际总时程。
