Sodium dodecyl sulphate polyacrylamide gel electrophoresis patterns of proteinuria in various renal diseases of childhood

Abstract

This study examined the potential of an automated electrophoretic system (PHASTSYSTEM, Pharmacia. Uppsala, Sweden) to distinguish patterns of proteinuria in children with various renal diseases. It proved possible to produce ready-to-read sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE) separation of 1 microliter of unconcentrated urine in 2 h. Glomerular, tubular and mixed patterns of proteinuria were identified. Steroid-responsive nephrotic syndrome (SRNS) was readily identified by strong bands of albumin and transferrin during relapses. In contrast, steroid-resistant nephrotic syndrome was associated with two additional bands of haptoglobin and IgG. Albumin dimers (Mr 120 kDa) were found in the active phase of the disease in the urine of 90% of children with SRNS. Patterns of tubular proteinuria were found in children with proximal renal tubular abnormalities. The presence of mixed patterns of glomerular and tubular proteinuria strongly suggest renal insufficiency. SDS PAGE electrophoresis can readily be applied in clinical practice. It may prove helpful in the diagnosis and management of children with renal diseases enabling correlation to be made between proteinuria, renal pathology and prognosis.

A boy with congenital analbuminemia and steroid-sensitive idiopathic nephrotic syndrome: an experiment of nature

“…Proteinuria mainly consists of albumin, but other proteins including transferrin [3] and gamma globulins (IgG, subclasses) [1,17] are also lost in the urine though to a much lesser amount.…”

Progressive glomerular toxicity of ifosfamide in children

“…The argument for later onset and progressive nature is further strengthened by the fact that two of the children with clinical glomerular impairment were part of our previously published report [8]. They showed evidence of subclinical glomerular impairment by SDS-PAGE urine protein electrophoresis [29], 6 and 7 months after the end of therapy. Median follow-up in previous studies [26,27] was considerably less than ours and this may be a reason for their lower incidence.…”

Differentiation of proteinurias with electrophoresis

“…The introduction of the Phast system has now increased access to sodium dodecyl sulphate (SDS)-PAGE. As Brocklebank et al [23] point out, the technique is easy to use in clinical practice and results are available in 2 h. However, the short separation distance of only 4 cm does not allow resolution of closely adjacent bands. Since the application volume is Offprint requests to: J. H. H. Ehrich restricted to 1 gl, albumin is normally the only protein band detected in urines of physiological protein concentration (<0.1 g/l).…”

“…In this issue of the journal, Brocklebank et al [23] report the use of a commercially available, automated electrophoretic system (Phast system, Pharmacia, Uppsala, Sweden) to distinguish glomerular, tubular and a mixed gtomerulotubular pattern of proteinuria in children with various renal diseases. The method was used to separate urinary proteins in 1 gl unconcentrated urine taken from healthy or diseased children.…”

“…Almost 25 years later, Davies [3] and Ornstein [4] published the theory and practice of disc electrophoresis allowing the differentiation of urinary proteins according to their molecular weight. In the following years, many variations [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] of the polyacrylamide gel electrophoresis (PAGE) principle have been developed for use in nephrology (Table 1) and numerous publications have classified proteinurias according to different urinary protein molecular weight patterns [22,[24][25][26][27][28][29][30][31]. However, problems remain and many paediatric and adult nephrologists do not use PAGE routinely.…”