Bakker Winston W, van Dael Catharina M L, Pierik Leonie J W M, van Wijk Joanna A E, Nauta Jeroen, Borghuis Theo, Kapojos Jola J
Department of Pathology, University Medical Center, Groningen, The Netherlands.
Pediatr Nephrol. 2005 Oct;20(10):1410-5. doi: 10.1007/s00467-005-1936-3. Epub 2005 Aug 4.
Since an active isoform of plasma hemopexin (Hx) has been proposed to be a potential effector molecule in minimal change disease (MCD), we tested plasma and urine samples from subjects with MCD in relapse (n = 18) or in remission (n = 23) (after treatment with prednisolone) for presence or activity of Hx. For comparison, plasma or urine from proteinuric subjects with focal and segmental glomerulosclerosis (FSGS, n = 11), membranoproliferative glomerulonephritis (MPGN, n = 9), IgA nephropathy (n = 5) or healthy control donors (n = 10), were incorporated into the study. Electrophoresis and Western blotting methods were used for evaluation of the Hx status, whereas protease activity of Hx was tested upon kidney tissue in vitro according to standard methods. The results show (1) a decreased mean titer of plasma Hx exclusively in MCD relapse subjects as compared with MCD in remission (0.21+/-0.14 mg/ml vs 0.44+/-0.06 mg/ml; p < 0.01). Mean Hx titers in other proteinuric subjects ranged from 0.38+/-0.05 mg/ml to 0.40+/- 0.06 mg/ml, whereas, the mean titer of healthy controls was 0.59+/-0.03 mg Hx/ml; (2) an increased Hx activity (expressed in arbitrary units) exclusively in plasma from MCD relapse subjects (3.3+/-0.72 vs 1.16+/-0.56, MCD remission; p < 0.01); (3) different Western blot patterns in MCD relapse vs remission plasma; (4) reduced stainability or virtual absence of the 80-kD Hx band in blots of urine from MCD relapse in contrast to urine samples from other proteinuric subjects with FSGS, MPGN, or IgA nephropathy. It is concluded that Hx in MCD relapse subjects may exist in an altered isoform, showing enhanced protease activity as compared with subjects in remission, subjects with other forms of primary glomerulopathy, or healthy control individuals.
由于血浆血红素结合蛋白（Hx）的一种活性异构体被认为是微小病变病（MCD）中一种潜在的效应分子，我们检测了18例复发期MCD患者和23例缓解期MCD患者（经泼尼松龙治疗后）的血浆和尿液样本中Hx的存在情况或活性。为作比较，研究纳入了11例局灶节段性肾小球硬化（FSGS）、9例膜增生性肾小球肾炎（MPGN）、5例IgA肾病的蛋白尿患者以及10例健康对照者的血浆或尿液。采用电泳和蛋白质印迹法评估Hx状态，而Hx的蛋白酶活性则根据标准方法在体外肾脏组织上进行检测。结果显示：（1）与缓解期MCD患者相比，复发期MCD患者血浆Hx平均滴度降低（0.21±0.14mg/ml对0.44±0.06mg/ml；p<0.01）。其他蛋白尿患者的Hx平均滴度在0.38±0.05mg/ml至0.40±0.06mg/ml之间，而健康对照者的平均滴度为0.59±0.03mg Hx/ml；（2）仅复发期MCD患者血浆中的Hx活性增加（以任意单位表示）（3.3±0.72对缓解期MCD的1.16±0.56；p<0.01）；（3）复发期与缓解期MCD血浆的蛋白质印迹模式不同；（4）与FSGS、MPGN或IgA肾病等其他蛋白尿患者的尿液样本相比，复发期MCD患者尿液印迹中80-kD Hx条带的染色性降低或几乎不存在。结论是，复发期MCD患者的Hx可能以一种改变的异构体形式存在，与缓解期患者、其他形式原发性肾小球病患者或健康对照个体相比，其蛋白酶活性增强。
