Using a structured, formal meta-analytic technique with rigorous data selection, conditioning and quality assessment, we attempted to structure clinically relevant guidelines for managing vesicoureteral reflux in children. The lack of robust prospective randomized controlled trials limits the strength of these guidelines but they can serve to provide a framework for practice and set boundaries for safe and effective practice. As new data emerge, these guidelines will necessarily evolve.

Stem cells are believed to regulate normal prostatic homeostasis and to play a role in the etiology of prostate cancer and benign prostatic hyperplasia. We show here that the proximal region of mouse prostatic ducts is enriched in a subpopulation of epithelial cells that exhibit three important attributes of epithelial stem cells: they are slow cycling, possess a high in vitro proliferative potential, and can reconstitute highly branched glandular ductal structures in collagen gels. We propose a model of prostatic homeostasis in which mouse prostatic epithelial stem cells are concentrated in the proximal region of prostatic ducts while the transit-amplifying cells occupy the distal region of the ducts. This model can account for many biological differences between cells of the proximal and distal regions, and has implications for prostatic disease formation.

Urothelium synthesizes a group of integral membrane proteins called uroplakins, which form two-dimensional crystals (urothelial plaques) covering >90% of the apical urothelial surface. We show that the ablation of the mouse uroplakin III (UPIII) gene leads to overexpression, defective glycosylation, and abnormal targeting of uroplakin Ib, the presumed partner of UPIII. The UPIII-depleted urothelium features small plaques, becomes leaky, and has enlarged ureteral orifices resulting in the back flow of urine, hydronephrosis, and altered renal function indicators. Thus, UPIII is an integral subunit of the urothelial plaque and contributes to the permeability barrier function of the urothelium, and UPIII deficiency can lead to global anomalies in the urinary tract. The ablation of a single urothelial-specific gene can therefore cause primary vesicoureteral reflux (VUR), a hereditary disease affecting ∼1% of pregnancies and representing a leading cause of renal failure in infants. The fact that VUR caused by UPIII deletion seems distinct from that caused by the deletion of angiotensin receptor II gene suggests the existence of VUR subtypes. Mutations in multiple gene, including some that are urothelial specific, may therefore cause different subtypes of primary reflux. Studies of VUR in animal models caused by well-defined genetic defects should lead to improved molecular classification, prenatal diagnosis, and therapy of this important hereditary problem.

Endoscopic treatment provides a high rate of success in children with reflux that decreases with increasing grade, although multiple treatments may be necessary. Future reports of endoscopic therapy should include rates of urinary tract infection and renal scarring.

The apical surface of mouse urothelium is covered by two-dimensional crystals (plaques) of uroplakin (UP) particles. To study uroplakin function, we ablated the mouse UPII gene. A comparison of the phenotypes of UPII- and UPIII-deficient mice yielded new insights into the mechanism of plaque formation and some fundamental features of urothelial differentiation. Although UPIII knockout yielded small plaques, UPII knockout abolished plaque formation, indicating that both uroplakin heterodimers (UPIa/II and UPIb/III or IIIb) are required for plaque assembly. Both knockouts had elevated UPIb gene expression, suggesting that this is a general response to defective plaque assembly. Both knockouts also had small superficial cells, suggesting that continued fusion of uroplakin-delivering vesicles with the apical surface may contribute to umbrella cell enlargement. Both knockouts experienced vesicoureteral reflux, hydronephrosis, renal dysfunction, and, in the offspring of some breeding pairs, renal failure and neonatal death. These results highlight the functional importance of uroplakins and establish uroplakin defects as a possible cause of major urinary tract anomalies and death.

These results provide the first in vivo evidence that THP is a critical urinary defense factor and suggest that its deficiency could be an important contributing factor in human nephrolithiasis, a condition afflicting tens of millions of people in the world annually.

The specific features of the prostate adenoma predisposing to the development of symptomatic benign prostatic hyperplasia (BPH) are unknown. Our objective was to determine whether the histological composition of the prostate adenoma is related to the development of symptomatic BPH. Prostate adenomas were obtained from men with asymptomatic BPH undergoing cystoprostatectomy for invasive transitional cell carcinoma, and from men with symptomatic BPH undergoing open prostatectomy, transurethral resection of the prostate and pharmacotherapy. The severity of bladder outlet obstruction was evaluated with the Boyarsky symptom score and uroflowmetry. The percentages of stroma, epithelium and glandular lumen were determined in the prostate adenomas via quantitative image analysis on a computer-assisted morphometry system. The prostate adenomas from the 33 men with symptomatic BPH contained 62 +/- 1%, 15 +/- 1% and 23 +/- 1 of stroma, epithelium and glandular lumen, respectively. The prostate adenomas from 6 men with asymptomatic disease contained 54 +/- 1%, 21 +/- 1% and 25 +/- 1% of stroma, epithelium and glandular lumen, respectively. The ratios of stromal-to-epithelial hyperplasia in the prostate adenomas from men with symptomatic and asymptomatic disease were 4.6 +/- 0.3 and 2.7 +/- 0.1, respectively. The differences in percentage of stroma and epithelium, and the stromal-to-epithelial ratio in the prostate adenomas from men with symptomatic and asymptomatic BPH were statistically significant. Our study suggests that the histological composition of the prostate adenoma is related to the development of symptomatic BPH.

The adhesion of uropathogenic Escherichia coli to the urothelial surface of the bladder is a prerequisite for the establishment of bladder infections. This adhesion process relies on E. coli adhesins and their cognate urothelial receptors, and it also is influenced by an intricate array of defense mechanisms of the urinary system. In this study, we examined the in vivo role of Tamm-Horsfall protein (THP), the most abundant urinary protein, in innate urinary defense. We genetically ablated the mouse THP gene and found that THP deficiency predisposes mice to bladder infections by type 1-fimbriated E. coli. Inoculation of too few type 1-fimbriated E. coli to colonize wild-type mice caused significant bladder colonization in THP-knockout mice. In contrast, THP deficiency did not enhance the ability of P-fimbriated E. coli to colonize the bladder. Our results provide the first in vivo evidence indicating that under physiological conditions, the mannosylated THP can serve as an effective soluble "receptor," binding to the type 1-fimbriated E. coli and competitively inhibiting them from adhering to the uroplakin Ia receptors present on the urothelial surface. These results suggest that potential THP defects, either quantitative or qualitative, could predispose the urinary bladder to bacterial infections. The generation of THP-deficient mice established the role of THP as a first line of urinary defense and should help elucidate other potential functions of this major protein in urinary tract physiology and diseases.