Molecular events involved in the morphogenesis of multicystic dysplastic kidney.
BACKGROUND
Wnt-1 is capable of inducing metanephric mesenchyme to undergo tubulogenesis. A relationship between the degree of cystogenesis and reduced E-cadherin (E-cad) expression was described. Syndecan-1 (Sdc-1) has a critical role in kidney development.


METHODS
Ten multicystic dysplastic kidneys (MCDKs) were stained with hematoxylin and eosin and immunohistochemistry was performed using Wnt-1, E-cad and Sdc-1 antibodies. Eight unaffected kidneys were used as controls.


RESULTS
Strong Wnt-1 immunostaining occurred inside cystic/tubular epithelial cells and in blastematous foci. An immunoreaction was observed in glomerular epithelial cells. In controls, just weak cytoplasmic Wnt-1 positivity was seen in tubular epithelial cells. E-cad reaction was negative in MCDKs while strong immunostaining was common in tubular cells of controls. A strong Sdc-1 immunoreaction depicted cystic, tubular and glomerular epithelial cells in MCDKs while Sdc-1 expression documented weak positivity in tubular epithelium alone.


CONCLUSIONS
Our data are in accordance with an involvement of Wnt-1 in normal nephrogenesis and with its role in altered epithelial differentiation of metanephric mesenchyme in MCDKs. Wnt-1 signal may function to suppress E-cad expression, a predisposing event for cystogenesis. High expression of Sdc-1 in tubular/cystic epithelial cells of MCDKs might alter the normal transition of stages of the developmental process and modify the anion charge of the glomerular barrier.
Unit of Pediatric Surgery, Department of Pediatric Surgery, University of Catania, Catania, Italy. arenasal @ inwind.it
Salvatore
S
Arena
Carmine
C
Fazzari
Maria Grazia
MG
Scuderi
Alessandra
A
Implatini
Daniela
D
Villari
Santo
S
Torre
Francesco
F
Arena
Vincenzo
V
Di Benedetto
D015703:Antigens, CD; D015820:Cadherins / Q000032:analysis; D016022:Case-Control Studies; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007668:Kidney / Q000737:chemistry* / Q000196:embryology / Q000254:growth & development; D009024:Morphogenesis; D021782:Multicystic Dysplastic Kidney / Q000196:embryology / Q000378:metabolism*; D015398:Signal Transduction; D053668:Syndecan-1 / Q000032:analysis; D051155:Wnt1 Protein / Q000032:analysis
D015703:Antigens, CD; C513384:CDH1 protein, human; D015820:Cadherins; C508241:SDC1 protein, human; D053668:Syndecan-1; C495247:WNT1 protein, human; D051155:Wnt1 Protein