RED CELL MEMBRANE CHARGE
DEFECT AND PROTEINURIA IN CHILDREN WITH NEPHROTIC SYNDROME
Barakat SH, Abd-Alrahman EM*
Department of Pediatrics, Department of Medical
Biochemistry*
Faculty of Medicine- University of Alexandria, Alexandria, Egypt
It has been postulated that the loss of charge on the glomerular
basement membrare (GBM) in steroid- responsive nephrotic syndrome (SRNS) is
a generalized disorder affecting all membranes including membranes of red
blood cells (RBC).
Methods: The negative charge on RBC membranes had been
measured using the technique of alcian blue (AB) binding to RBC (ABRBC) in
20 children with nephrotic syrdrome (NS). 10 children with SRNS (studied in
relapse and after remission) 5 children with membranoproliferative
glomerulonephritis (MPGN) and 5 children with focal glomerulosclerosis
(FGS). Size selectivity of GBM was also measured indirecty by fine analysis
of urinary protein with sodium dodecyl sulfate- polyacrylamide gel
electrophoresis in those children.
Results: ABRBC was significantly reduced in all studied
nephrotic children when compared with healthy children. This reduction was
greater in SRNS and showed significant increase after remission
(p<0.05). A strong inverse correlation was detected between the degree
of proteinuria and ABRBC in SRNS (r =-0.97)only . Excretion of glomerular
proteins was restricted by size (< 80 kd) in SRNS but unrestricted
(<80 kd plus>80kd) in F G S and MPGN.
Conclusion: These findings suggest that a
generalized loss of membrane negative charge accurs in SRNS, and that the
reduction in glomerular anionic sites may be only partly responsible for
proteinuria in different types of childhood nephrosis, except for SRNS,
where it probably plays a major role.