TGF-beta mRNA expression in the renal pelvis after experimental and clinical ureteropelvic junction obstruction

Purpose: The renal parenchymal expression of transforming growth factor-beta (TGF-beta) is increased in experimental obstructive uropathy. To better understand the pathophysiology of hydronephrosis, we pursued this observation by determining if the expression of TGF-beta is also increased in the obstructed renal pelvis. Materials and Methods: The expression of TGF-beta mRNA was evaluated in experimental and clinical ureteropelvic junction obstruction by reverse transcriptase polymerase chain reaction (RT-PCR). Southern blot analysis with labeled human cDNA probes for TGF-beta was then done to verify the results. Results: Experimentally, pelves subjected to ureteral constriction showed significantly higher TGF-beta mRNA expression than normals. After reversal of obstruction, the expression of TGF-beta remained significantly higher than normals but was not different from pelves with ongoing obstruction. Clinically, there was a significantly higher level of TGF-beta mRNA expression in obstructed pelves than in nonobstructed ureters. High levels of TGF-beta mRNA expression correlated significantly with good clinical outcome, good renal function, muscle hypertrophy and acute onset of obstruction. Conclusions: There is increased TGF-beta mRNA expression in the renal pelvis following clinical and experimental ureteropelvic junction obstruction. These data implicate TGF-beta in the adaptive molecular responses that increase muscle and collagen elaboration seen in hydronephrosis.