Faculty Bibliography

Prostate carcinoma and benign prostatic hypertrophy may both originate in stem cells, highlighting the importance of the characterization of these cells. The prostate gland contains a network of ducts each of which consists of a proximal (adjacent to the urethra), an intermediate, and a distal region. Here, we report that two populations of cells capable of regenerating prostatic tissue in an in vivo prostate reconstitution assay are present in different regions of prostatic ducts. The first population (with considerable growth potential) resides in the proximal region of ducts and in the urethra, and the survival of these cells does not require the presence of androgens. The second population (with more limited growth potential) is found in the remaining ductal regions and requires androgen for survival. In addition, we find that primitive proximal prostate cells that are able to regenerate functional prostatic tissue in vivo are also programmed to re-establish a proximal-distal ductal axis. Similar to their localization in the intact prostate, cells with the highest regenerative capacity are found in the proximal region of prostatic ducts formed in an in vivo prostate reconstitution assay. The primitive proximal cells can be passaged through four generations of subrenal capsule grafts. Together, these novel findings illustrate features of primitive prostate cells that may have implications for the development of therapies for treating proliferative prostatic diseases

PURPOSE: Current American Urological Association treatment guidelines for vesicoureteral reflux do not include any recommendations pertaining to endoscopic therapy (subureteral injection of bulking agent). We performed a meta-analysis of the existing literature pertaining to endoscopic treatment to allow comparison with reports of open surgical correction. MATERIALS AND METHODS: We searched all peer reviewed articles published through 2003 pertaining to endoscopic treatment of vesicoureteral reflux. A total of 63 articles were double reviewed by 9 pediatric urologists, and the data were tabulated on data retrieval sheets. A mixed effects logistic regression model was used to obtain overall estimates of event probabilities (eg reflux resolution, ureteral obstruction) together with their 95% confidence intervals. Individual study estimates were obtained with overall estimate and observation characteristics using empirical Bayes calculations. Differences between or among specific groups were assessed using the F-test. RESULTS: The database included 5,527 patients and 8,101 renal units. Following 1 treatment the reflux resolution rate (by ureter) for grades I and II reflux was 78.5%, grade III 72%, grade IV 63% and grade V 51%. If the first injection was unsuccessful, the second treatment had a success rate of 68%, and the third treatment 34%. The aggregate success rate with 1 or more injections was 85%. The success rate was significantly lower for duplicated (50%) vs single systems (73%), and neuropathic (62%) vs normal bladders (74%). The success rate was similar among children and adults. Following a previous failed open reimplantation endoscopic treatment was successful in 65% of patients. After endoscopic treatment with variable followup pyelonephritis developed in 0.75% of patients and cystitis in 6%. There were few reports of renal scarring following treatment. CONCLUSIONS: 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

Although the epithelial lining of much of the mammalian urinary tract is known simply as the urothelium, this epithelium can be divided into at least three lineages of renal pelvis/ureter, bladder/trigone, and proximal urethra based on their embryonic origin, uroplakin content, keratin expression pattern, in vitro growth potential, and propensity to keratinize during vitamin A deficiency. Moreover, these cells remain phenotypically distinct even after they have been serially passaged under identical culture conditions, thus ruling out local mesenchymal influence as the sole cause of their in vivo differences. During vitamin A deficiency, mouse urothelium form multiple keratinized foci in proximal urethra probably originating from scattered K14-positive basal cells, and the keratinized epithelium expands horizontally to replace the surrounding normal urothelium. These data suggest that the urothelium consists of multiple cell lineages, that trigone urothelium is closely related to the urothelium covering the rest of the bladder, and that lineage heterogeneity coupled with cell migration/replacement form the cellular basis for urothelial squamous metaplasia

PURPOSE:: Development and differentiation of the human fetal prostate are androgen dependent and follow a specific pattern of solid bud-ductal morphogenesis, which involves stromal-epithelial interactions. Androgen receptor associated protein 55 (ARA55) an androgen receptor coactivator localized in stromal cells, binds to androgen receptor (AR) and regulates androgen receptor translocation and transcriptional activity. We investigated whether ARA55 has a role in human prostate development. MATERIALS AND METHODS:: ARA55 expression was examined in 25 human prostates from fetuses at gestational ages 10 to 40 weeks and compared to the expression of 34betaE12 (a basal cell marker), smooth muscle actin, desmin (a smooth muscle marker), vimentin (a mesenchymal marker) and Ki-67 (a proliferation marker) by immunohistochemistry. RESULTS:: Prostatic epithelium appeared as solid epithelial buds from the urogenital sinus. It underwent arborization and ductal differentiation from the center to the periphery. ARA55 was expressed in stromal cells with a zonal pattern, primarily in the peripheral zone surrounding the noncanalized acini. Most cells in solid buds were positive for 34betaE12, while only basal layer cells in the centrally located epithelial ducts stained with 34betaE12. Solid buds also had a higher proliferation index than ducts. In addition, ARA55 expressing stromal cells but not ARA55 negative stromal cells showed smooth muscle differentiation. CONCLUSIONS:: The intimate relationship between ARA55 expressing stromal cells and mitotically active, noncanalized acini suggests that ARA55 has a role in the stromal-epithelial interaction involved in fetal prostate development

PURPOSE: Neurogenic bladder is a major problem for children with spina bifida. Despite rigorous pharmacological and surgical treatment, incontinence, urinary tract infections and upper tract deterioration remain problematic. We have previously demonstrated the ability to establish surgically a skin-central nervous system-bladder reflex pathway in patients with spinal cord injury with restoration of bladder storage and emptying. We report our experience with this procedure in 20 children with spina bifida. MATERIALS AND METHODS: All children with spina bifida and neurogenic bladder underwent limited laminectomy and a lumbar ventral root (VR) to S3 VR microanastomosis. The L5 dorsal root was left intact as the afferent branch of the somatic-autonomic reflex pathway after axonal regeneration. All patients underwent urodynamic evaluation before and after surgery. RESULTS: Preoperative urodynamic studies revealed 2 types of bladder dysfunction- areflexic bladder (14 patients) and hyperreflexic bladder with detrusor external sphincter dyssynergia (6). All children were incontinent. Of the 20 patients 17 gained satisfactory bladder control and continence within 8 to 12 months after VR microanastomosis. Of the 14 patients with areflexic bladder 12 (86%) showed improvement. In these cases bladder capacity increased from 117.28 to 208.71 ml, and mean maximum detrusor pressure increased from 18.35 to 32.57 cm H2O. Five of the 6 patients with hyperreflexic bladder demonstrated improvement, with resolution of incontinence. Urodynamic studies in these cases revealed a change from detrusor hyperreflexia with detrusor external sphincter dyssynergia and high detrusor pressure to nearly normal storage and synergic voiding. In these cases mean bladder capacity increased from 94.33 to 177.83 ml, and post-void residual urine decreased from 70.17 to 23.67 ml. Overall, 3 patients failed to exhibit any improvement. CONCLUSIONS: The artificial somatic-autonomic reflex arc procedure is an effective and safe treatment to restore bladder continence and reverse bladder dysfunction for patients with spina bifida

PURPOSE: Congenital mid ureteral stricture is rare. We report 7 cases, and discuss the differences in preoperative evaluation and surgical management compared to other obstructive entities. MATERIALS AND METHODS: Medical records and imaging studies of 7 children identified with mid ureteral strictures between 1998 and 2002 were reviewed retrospectively. Five newborns presented with prenatal hydronephrosis, and 2 children presented at age 15 years, one in the course of evaluation of blunt trauma, and one due to pain and abdominal mass. Imaging studies included renal ultrasound, voiding cystourethrography, radionuclide renography and computerized tomography. All patients underwent retrograde pyelography. Pathological examination of each specimen was undertaken at the respective institutions. RESULTS: Prenatal hydronephrosis was the most common presentation. There were no urinary tract infections. All patients had significant obstruction on the affected side. No patient had vesicoureteral reflux. After imaging but before surgery the urinary obstruction was believed to be at the ureteropelvic junction in 4 patients and the ureterovesical junction in 2, and secondary to posterior urethral valves in 1. At cystoscopy all of the affected ureters had a normally located and normally configured orifice. Retrograde pyelography led to an accurate diagnosis of mid ureteral narrowing in all patients. Six patients underwent ureteroureterostomy, all of whom had satisfactory outcomes. In 1 of these patients contralateral nephrectomy was performed due to nonfunction of the multicystic dysplastic kidney. The remaining patient underwent nephrectomy for ipsilateral end stage kidney disease and hydronephrosis. In this patient the ureters were stenotic and suggested asymmetry in the thickness of the muscular coat, perhaps secondary to extrinsic compression. CONCLUSIONS: Congenital mid ureteral stricture is rare. Renal ultrasound and radionuclide renography alone do not reliably demonstrate the site of obstruction. Retrograde pyelography at the time of surgical correction of presumed ureteral obstruction is an important adjunct for correctly identifying the site of narrowing in the affected ureteral segment, unless the ureter has been imaged with another modality

PURPOSE:: We examined the immunolocalization of estrogen receptor (ER)alpha and ERbeta in the human fetal prostate. MATERIALS AND METHODS:: Tissue sections from human fetal prostates at 7 to 22 weeks of gestation were stained with antibodies to ERalpha, ERbeta, and cytokeratin 10 and 14. RESULTS:: ERalpha expression was not detected until 15 weeks of gestation with sparse staining in the utricle. By 19 weeks increased ERalpha expression was seen in the luminal cells of the ventral urogenital epithelium (UGE), basal cells of the dorsal UGE, utricle, distal periurethral ducts, peripheral stroma and posterior prostatic duct. K14 was detected in basal cells of the UGE and in several posterior acini. At 22 weeks ERalpha expression was more intense in all of these areas. ERbeta was expressed throughout the UGE, ejaculatory ducts, mullerian ducts and entire stroma at 7 weeks. Intense ERbeta staining was observed in these areas and in the prostatic buds by 8 weeks with persistent intense staining through 22 weeks. CONCLUSIONS:: To our knowledge we report the first immunolocalization of ERalpha in the human fetal prostate and the earliest demonstration of ERbeta expression in the prostate at 7 weeks of gestation. ERbeta expression is intense during ductal morphogenesis, suggesting a role in normal glandular growth and proliferation. The induction of squamous metaplasia in the UGE, distal periurethral ducts and utricle is associated with ERalpha expression in these areas, while the induction of squamous metaplasia in peripheral prostatic acini is associated with peripheral stromal ERalpha expression. This study suggests estrogen signaling pathways in the human fetal prostate via ERalpha that involve epithelial-epithelial and epithelial-stromal interactions

The biological ramifications of phosphorylation of the androgen receptor (AR) are largely unknown. To examine the phosphorylation of AR at serine 213, a putative substrate for Akt, a phosphorylation site-specific antibody was generated. The use of this antibody indicated that AR Ser-213 is phosphorylated in vivo and that phosphorylation is tightly regulated in a cell type-specific manner. Furthermore, Ser-213 phosphorylation took place with rapid kinetics and was inhibited by the phosphatidylinositol 3-kinase inhibitor LY294002. Phosphorylation occurred in response to R1881 and dihydrotestosterone but weakly if at all in response to testosterone. It did not occur in response to AR antagonists or growth factor stimulation in the absence of an AR agonist. Transcription assays using an AR-responsive reporter gene construct showed that activated phosphatidylinositol 3-kinase inhibited transcription mediated by wild type AR but not that of a mutant AR variant (S213A), which could not be phosphorylated at Ser-213. By immunohistochemistry, the AR Ser(P)-213 antigen was detected in prostate epithelial but not stromal cells despite the fact that an antibody recognizing both phosphorylated and non-phosphorylated forms of AR demonstrates that AR is present in both cell types as expected. In fetal tissue the AR-Ser(P)-213 antigen was present in epithelial cells of the urogenital sinus when endogenous androgen levels were high and activated Akt was prevalent, but absent at a later stage of development when endogenous androgen levels were low and Akt activation was minimal. Immunoreactivity was evident in differentiated cells lining the lumen of the urogenital sinus but not in rapidly dividing, Ki67 positive cells within the developing prostate or stromal tissue, suggesting that site-specific phosphorylation of AR Ser-213 by cellular kinases occurs in a non-proliferating cellular milieu