Background: Several genes transiently expressed during the maturation of the metanephrogenic mesenchyme have been reported in recent years while there is accumulating evidence of a reverted developmental pathway during tissue damage and loss of function.
Methods: Here we studied the expression of nine genes associated with kidney maturation from samples of normal human fetal, juvenile and adult kidneys and cultured glomerular cells using Northern blotting analysis. Subsequently, kidneys from patients with congenital nephrotic syndrome of the Finnish type (CNF), presenting with heavy proteinuria, and Wilms' tumor tissue were studied for the corresponding expression pattern for evidence of dedifferentiation/persistence of a fetal expression pattern.
Results: All the genes studied had their distinct expression pattern within the tissues and cells tested. No conclusive evidence of dedifferentiation could be obtained in the samples from CNF kidneys, whereas, as expected, the gene expression pattern of Wilms' tumor tissue was highly similar to that of fetal kidney tissue.
Conclusion: Some genes thought to be only transiently expressed during kidney maturation were, however, constantly found in the samples from fetal to newborn and adult kidneys.