Sackmann H, Tran-Van T, Tack I, Hanaire-Broutin H, Tauber J P, Ader J L
Service d'Endocrinologie-Diabétologie, Rangueil University Hospital, Toulouse, France.
Diabetologia. 1998 Jan;41(1):86-93. doi: 10.1007/s001250050871.
The aim of this study was to determine whether renal functional reserve (RFR) is altered in insulin-dependent diabetic (IDDM) patients according to the stage of diabetic nephropathy. RFR was examined in 33 IDDM patients in similar glycaemic and metabolic control and compared to 12 healthy control subjects, during eight 1 h clearance periods prior to, during and after a 3-h stimulation by amino acid infusion (4.5 mg x kg(-1) x min[-1]). RFR was calculated as the difference between stimulated and baseline glomerular filtration rates (GFR). In 14 early normotensive diabetic patients with normal urinary albumin excretion, mean baseline GFR (133 +/- 3 ml x min(-1) x 1.73 m[-2]) was higher whereas RFR (10 +/- 4 ml x min(-1) x 1.73 m[-2]) was lower (p < 0.05) than in control subjects (113 +/- 4 and 28 +/- 2 ml x min(-1) x 1.73 m(-2), respectively). In 10 normotensive patients who had lived with IDDM for 16 years and who had microalbuminuria, baseline GFR and RFR (109 +/- 7 and 24 +/- 6 ml x min(-1) x 1.73 m(-2), respectively) were similar to those in control subjects. In 9 patients who had suffered IDDM for 23 years and had developed macroalbuminuria and hypertension, baseline GFR (78 +/- 8 ml x min(-1) x 1.73 m[-2]) was lower than in control subjects (p < 0.05) and RFR (8 +/- 4 ml x min(-1) x 1.73 m[-2]) was not significant. In addition, renal vascular resistance decreased significantly during infusion (p < 0.05) in microalbuminuric normotensive patients as well as in control subjects (by 9 +/- 4 and 11 +/- 4 mmHg x l(-1) x min(-1) x 1.73 m(-2), respectively) but not in normoalbuminuric normotensive or macroalbuminuric hypertensive patients. These results indicate that microalbuminuric normotensive patients retain a normal RFR, whereas RFR is reduced or suppressed at two opposite stages of the disease: in normoalbuminuric normotensive patients with a high GFR and in macroalbuminuric hypertensive patients with a decreased GFR. This dissimilar impairment reveals permanent glomerular hyperfiltration in both early IDDM without nephropathy and IDDM with overt diabetic nephropathy, but not in IDDM with incipient nephropathy.
本研究的目的是根据糖尿病肾病的阶段，确定胰岛素依赖型糖尿病（IDDM）患者的肾功储备（RFR）是否发生改变。在33例血糖和代谢控制相似的IDDM患者中检测RFR，并与12例健康对照者进行比较。在通过输注氨基酸（4.5mg·kg⁻¹·min⁻¹）进行3小时刺激之前、期间和之后的8个1小时清除期内进行检测。RFR计算为刺激后和基线肾小球滤过率（GFR）之间的差值。在14例早期血压正常、尿白蛋白排泄正常的糖尿病患者中，平均基线GFR（133±3ml·min⁻¹·1.73m⁻²）较高，而RFR（10±4ml·min⁻¹·1.73m⁻²）低于对照组（分别为113±4和28±2ml·min⁻¹·1.73m⁻²，p<0.05）。在10例患有IDDM 16年且有微量白蛋白尿的血压正常患者中，基线GFR和RFR（分别为109±7和24±6ml·min⁻¹·1.73m⁻²）与对照组相似。在9例患有IDDM 23年且已出现大量白蛋白尿和高血压的患者中，基线GFR（78±8ml·min⁻¹·1.73m⁻²）低于对照组（p<0.05），RFR（8±4ml·min⁻¹·1.73m⁻²）无显著差异。此外，微量白蛋白尿的血压正常患者以及对照组在输注期间肾血管阻力显著降低（p<0.05）（分别降低9±4和11±4mmHg·l⁻¹·min⁻¹·1.73m⁻²），但正常白蛋白尿的血压正常患者或大量白蛋白尿的高血压患者未出现这种情况。这些结果表明，微量白蛋白尿的血压正常患者保留了正常的RFR，而在疾病的两个相反阶段RFR降低或受到抑制：在GFR高的正常白蛋白尿的血压正常患者和GFR降低的大量白蛋白尿的高血压患者中。这种不同的损害揭示了在无肾病的早期IDDM和有明显糖尿病肾病的IDDM中均存在永久性肾小球高滤过，但在有早期肾病的IDDM中不存在。
