[Expression of nephrin, podocin and a-actinine-4 in renal tissue of patients with proteinuria].
BACKGROUND
Slit diaphragm and/or podocyte's cytoskeleton alterations are related to proteinuria and nephrotic syndrome. In our population, focal and segmental glomerulosclerosis causing nephrotic syndrome is the more frequent biopsy demonstrated glomerulopathy. Our aim was search for alterations in some slit diaphragm-associated proteins in patients with nephrotic range proteinuria.


METHODS
Renal tissue from 40 patients with nephrotic range proteinuria, 10 patients with non-nephrotic proteinuria, 3 with isolated hematuria, and 10 samples of normal renal tissue (deceased donors) were studied, by indirect immunofluorescence, for expression of nephrin, podocin, and alpha-actinin-4.


RESULTS
Expression of these proteins was lineal, homogeneous, in the glomerular capillary walls in normal renal tissue and in patients with isolated hematuria. In nephrotic proteinuria this normal appearance was altered and immunostaining showed a fine granular appearance. In 18 cases (45%) of patients with nephrotic proteinuria and 3 cases (30%) of patients with non-nephrotic proteinuria there was loss of at least one of these proteins (p = 0.49). These alterations were found in the diverse glomerulopathies more frequently causing nephrotic syndrome.


CONCLUSIONS
In nephrotic range proteinuria redistribution or loss of expression of slit diaphragm-associated proteins is very frequent. In many of our cases this fact could be more a consequence than a cause of proteinuria. These alterations can be also evidenced in patients with non-nephrotic proteinuria.
Arias
L F
LF
Departamento de Patología, Universidad de Antioquia, Medellín, Colombia. luisfer_uda@yahoo.com
Vieco
B E
BE
Arteta
A A
AA
D000185:Actinin / Q000032:analysis / Q000096:biosynthesis*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D047908:Intracellular Signaling Peptides and Proteins / Q000032:analysis; D007668:Kidney / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008565:Membrane Proteins / Q000032:analysis / Q000096:biosynthesis*; D008875:Middle Aged; D011507:Proteinuria / Q000378:metabolism*; D055815:Young Adult
C111453:ACTN4 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C407223:NPHS2 protein; C113267:nephrin; D000185:Actinin