Faculty Bibliography

We have shown previously that during branching morphogenesis of the mouse prostate gland, Bone morphogenetic protein 7 functions to restrict Notch1-positive progenitor cells to the tips of the prostate buds. Here, we employed prostate-specific murine bi-genic systems to investigate the effects of gain and loss of Notch function during prostate development. We show that Nkx3.1(Cre) and Probasin(Cre) alleles drive expression of Cre recombinase to the prostate epithelium and periepithelial stroma. We investigated the effects of gain of Notch function using the Rosa(NI1C) conditional allele, which carries a constitutively active intracellular domain of Notch1 receptor. We carried out the analysis of loss of Notch function in Nkx3.1(Cre/+);RBP-J(flox/flox) prostates, where RBP-J is a ubiquitous transcriptional mediator of Notch signaling. We found that gain of Notch function resulted in inhibition of the tumor suppressor PTEN, and increase in cell proliferation and progenitor cells in the basal epithelium and smooth muscle compartments. In turn, loss of Notch/RBP-J function resulted in decreased cell proliferation and loss of epithelial and smooth muscle progenitors. Gain of Notch function resulted in an early onset of benign prostate hyperplasia by three months of age. Loss of Notch function also resulted in abnormal differentiation of the prostate epithelium and stroma. In particular, loss of Notch signaling and increase in PTEN promoted a switch from myoblast to fibroblast lineage, and a loss of smooth muscle. In summary, we show that Notch signaling is necessary for terminal differentiation of the prostate epithelium and smooth muscle, and that during normal prostate development Notch/PTEN pathway functions to maintain patterned progenitors in the epithelial and smooth muscle compartments. In addition, we found that both positive and negative modulation of Notch signaling results in abnormal organization of the prostate tissue, and can contribute to prostate disease in the adult organ

Lymphoid enhancer-binding factor (LEF)1 is a major mediator and a target in canonical Wnt/beta-catenin pathway. Interactions between the androgen receptor (AR) and canonical Wnt pathways have been implicated in the development of the genitourinary organs. Here, we investigated the localization and role of LEF1-positive cells during development of the prostate gland in human and in the murine model. We show that during human prostate development, LEF1 is restricted to the basal epithelial layer of the urogenital sinus. During mouse development, Lef1 is also present in the urogenital mesenchyme in addition to the basal epithelial layer of the urogenital sinus. In the course of elongation and branching of the prostatic ducts, Lef1 is localized to the proliferating epithelium at the distal tips of the buds. Notably, during branching morphogenesis, domains of Lef1 and AR are mutually exclusive. We further employed the TOPGAL reporter strain to examine the dynamics of Wnt signaling in the context of prostate regression upon a 7-d treatment with a competitive AR inhibitor, bicalutamide. We found that Wnt/Lef1-positive basal cells are not dependent upon androgen for survival. Furthermore, upon bicalutamide treatment, Wnt/Lef1-positive basal progenitors repopulated the luminal compartment. We conclude that Wnt/Lef1 activity identifies an androgen-independent population of prostate progenitors, which is important for embryonic development and organ maintenance and regeneration in the adult

PURPOSE: The American Urological Association established the Vesicoureteral Reflux Guideline Update Committee in July 2005 to update the management of primary vesicoureteral reflux in children guideline. The Panel defined the task into 5 topics pertaining to specific vesicoureteral reflux management issues, which correspond to the management of 3 distinct index patients and the screening of 2 distinct index patients. This report summarizes the existing evidence pertaining to children with diagnosed reflux including those young or older than 1 year without evidence of bladder and bowel dysfunction and those older than 1 year with evidence of bladder and bowel dysfunction. From this evidence clinical practice guidelines were developed to manage the clinical scenarios insofar as the data permit. MATERIALS AND METHODS: The Panel searched the MEDLINE(R) database from 1994 to 2008 for all relevant articles dealing with the 5 chosen guideline topics. The database was reviewed and each abstract segregated into a specific topic area. Exclusions were case reports, basic science, secondary reflux, review articles and not relevant. The extracted article to be accepted should have assessed a cohort of children with vesicoureteral reflux and a defined care program that permitted identification of cohort specific clinical outcomes. The reporting of meta-analysis of observational studies elaborated by the MOOSE (Meta-analysis Of Observational Studies in Epidemiology) group was followed. The extracted data were analyzed and formulated into evidence-based recommendations. RESULTS: A total of 2,028 articles were reviewed and data were extracted from 131 articles. Data from 17,972 patients were included in this analysis. This systematic meta-analysis identified increasing frequency of urinary tract infection, increasing grade of vesicoureteral reflux and presence of bladder and bowel dysfunction as unique risk factors for renal cortical scarring. The efficacy of continuous antibiotic prophylaxis could not be established with current data. However, its purported lack of efficacy, as reported in selected prospective clinical trials, also is unproven owing to significant limitations in these studies. Reflux resolution and endoscopic surgical success rates are dependent upon bladder and bowel dysfunction. The Panel then structured guidelines for clinical vesicoureteral reflux management based on the goals of minimizing the risk of acute infection and renal injury, while minimizing the morbidity of testing and management. These guidelines are specific to children based on age as well as the presence of bladder and bowel dysfunction. Recommendations for long-term followup based on risk level are also included. CONCLUSIONS: 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

PURPOSE: The American Urological Association established the Vesicoureteral Reflux Guideline Update Committee in July 2005 to update the management of primary vesicoureteral reflux in children guideline. The Panel defined the task into 5 topics pertaining to specific vesicoureteral reflux management issues, which correspond to the management of 3 distinct index patients and the screening of 2 distinct index patients. This report summarizes the existing evidence pertaining to screening of siblings and offspring of index patients with vesicoureteral reflux and infants with prenatal hydronephrosis. From this evidence clinical practice guidelines are developed to manage the clinical scenarios insofar as the data permit. MATERIALS AND METHODS: The Panel searched the MEDLINE(R) database from 1994 to 2008 for all relevant articles dealing with the 5 chosen guideline topics. The database was reviewed and each abstract segregated into a specific topic area. Exclusions were case reports, basic science, secondary reflux, review articles and not relevant. The extracted article to be accepted should have assessed a cohort of children, clearly stating the number of children undergoing screening for vesicoureteral reflux. Vesicoureteral reflux should have been diagnosed with a cystogram and renal outcomes assessed by nuclear scintigraphy. The screening articles were extracted into data tables developed to evaluate epidemiological factors, patient and renal outcomes, and results of treatment. The reporting of meta-analysis of observational studies elaborated by the MOOSE group was followed. The extracted data were analyzed and formulated into evidence-based recommendations regarding the screening of siblings and offspring in index cases with vesicoureteral reflux and infants with prenatal hydronephrosis. RESULTS: In screened populations the prevalence of vesicoureteral reflux is 27.4% in siblings and 35.7% in offspring. Prevalence decreases at a rate of 1 screened person every 3 months of age. The prevalence is the same in males and females. Bilateral reflux prevalence is similar to unilateral reflux. Grade I-II reflux is estimated to be present in 16.7% and grade III-V reflux in 9.8% of screened patients. The estimate for renal cortical abnormalities overall is 19.3%, with 27.8% having renal damage in cohorts of symptomatic and asymptomatic children combined. In asymptomatic siblings only the rate of renal damage is 14.4%. There are presently no randomized, controlled trials of treated vs untreated screened siblings with vesicoureteral reflux to evaluate health outcomes as spontaneous resolution, decreased rates of urinary infection, pyelonephritis or renal scarring. In screened populations with prenatal hydronephrosis the prevalence of vesicoureteral reflux is 16.2%. Reflux in the contralateral nondilated kidney accounted for a mean of 25.2% of detected cases for a mean prevalence of 4.1%. In patients with a normal postnatal renal ultrasound the prevalence of reflux is 17%. The prenatal anteroposterior renal pelvic diameter was not predictive of reflux prevalence. A diameter of 4 mm is associated with a 10% to 20% prevalence of vesicoureteral reflux. The prevalence of reflux is statistically significantly greater in females (23%) than males (16%) (p=0.022). Reflux grade distribution is approximately a third each for grades I-II, III and IV-V. The estimate of renal damage in screened infants without infection is 21.8%. When stratified by reflux grade renal damage was estimated to be present in 6.2% grade I-III and 47.9% grade IV-V (p <0.0001). The risk of urinary tract infection in patients with and without prenatal hydronephrosis and vesicoureteral reflux could not be determined. The incidence of reported urinary tract infection in patients with reflux was 4.2%. CONCLUSIONS: The meta-analysis provided meaningful information regarding screening for vesicoureteral reflux. However, the lack of randomized clinical trials for screened patients to assess clinical health outcomes has made evidence-based guideline recommendations difficult. Consequently, screening guidelines are based on present practice, risk assessment, meta-analysis results and Panel consensus