Yoram Mor

Multiple Imprinted and Stemness Genes Provide a Link between Normal and Tumor Progenitor Cells of the Developing Human Kidney

Wilms tumor (WT), the embryonic kidney malignancy, is suggested to evolve from a progenitor cell population of uninduced metanephric blastema, which typically gives rise to nephrons. However, apart from blastema, WT specimens frequently contain cells that have differentiated into renal tubular or stromal phenotypes, complicating their analysis. We aimed to define tumor-progenitor genes that function in normal kidney development using WT xenografts (WISH-WT), in which the blastema accumulates with serial passages at the expense of differentiated cells. Herein, we did transcriptional profiling using oligonucleotide microarrays of WISH-WT, WT source, human fetal and adult kidneys, and primary and metastatic renal cell carcinoma. Among the most significantly up-regulated genes in WISH-WT, we identified a surprising number of paternally expressed genes (PEG1/MEST, PEG3, PEG5/NNAT, PEG10, IGF2, and DLK1), as well as Meis homeobox genes [myeloid ecotropic viral integration site 1 homologue 1 (MEIS1) and MEIS2], which suppress cell differentiation and maintain self-renewal. A comparison between independent WISH-WT and WT samples by real-time PCR showed most of these genes to be highly overexpressed in the xenografts. Concomitantly, they were significantly induced in human fetal kidneys, strictly developmentally regulated throughout mouse nephrogenesis and overexpressed in the normal rat metanephric blastema. Furthermore, in vitro differentiation of the uninduced blastema leads to rapid down-regulation of PEG3, DLK1, and MEIS1. Interestingly, ischemic/reperfusion injury to adult mouse kidneys reinduced the expression of PEG3, PEG10, DLK1, and MEIS1, hence simulating embryogenesis. Thus, multiple imprinted and stemness genes that function to expand the renal progenitor cell population may lead to evolution and maintenance of WT.

Developmental tumourigenesis: NCAM as a putative marker for the malignant renal stem/progenitor cell population

During development, renal stem cells reside in the nephrogenic blastema. Wilms’ tumour (WT), a common childhood malignancy, is suggested to arise from the nephrogenic blastema that undergoes partial differentiation and as such is an attractive model to study renal stem cells leading to cancer initiation and maintenance. Previously we have made use of blastema‐enriched WT stem‐like xenografts propagated in vivo to define a ‘WT‐stem’ signature set, which includes cell surface markers convenient for cell isolation (frizzled homolog 2 [Drosophila] – FZD2, FZD7, G‐protein coupled receptor 39, activin receptor type 2B, neural cell adhesion molecule – NCAM). We show by fluorescence‐activated cell sorting analysis of sphere‐forming heterogeneous primary WT cultures that most of these markers and other stem cell surface antigens (haematopoietic, CD133, CD34, c‐Kit; mesenchymal, CD105, CD90, CD44; cancer, CD133, MDR1; hESC, CD24 and putative renal, cadherin 11), are expressed in WT cell sub‐populations in varying levels. Of all markers, NCAM, CD133 and FZD7 were constantly detected in low‐to‐moderate portions likely to contain the stem cell fraction. Sorting according to FZD7 resulted in extensive cell death, while sorted NCAM and CD133 cell fractions were subjected to clonogenicity assays and quantitative RT‐PCR analysis, exclusively demonstrating the NCAM+ fraction as highly clonogenic, overexpressing the WT ‘stemness’ genes and topoisomerase2A (TOP2A), a bad prognostic marker for WT. Moreover, treatment of WT cells with the topoisomerase inhibitors, Etoposide and Irinotecan resulted in down‐regulation of TOP2A along with NCAM and WT1. Thus, we suggest NCAM as a marker for the WT progenitor cell population. These findings provide novel insights into the cellular hierarchy of WT, having possible implications for future therapeutic options.

The isolation and characterization of renal cancer initiating cells from human Wilms' tumour xenografts unveils new therapeutic targets

There are considerable differences in tumour biology between adult and paediatric cancers. The existence of cancer initiating cells/cancer stem cells (CIC/CSC) in paediatric solid tumours is currently unclear. Here, we show the successful propagation of primary human Wilms tumour (WT), a common paediatric renal malignancy, in immunodeficient mice, demonstrating the presence of a population of highly proliferative CIC/CSCs capable of serial xenograft initiation. Cell sorting and limiting dilution transplantation analysis of xenograft cells identified WT CSCs that harbour a primitive undifferentiated – NCAM1 expressing – “blastema” phenotype, including a capacity to expand and differentiate into the mature renal‐like cell types observed in the primary tumour. WT CSCs, which can be further enriched by aldehyde dehydrogenase activity, overexpressed renal stemness and genes linked to poor patient prognosis, showed preferential protein expression of phosphorylated PKB/Akt and strong reduction of the miR‐200 family. Complete eradication of WT in multiple xenograft models was achieved with a human NCAM antibody drug conjugate. The existence of CIC/CSCs in WT provides new therapeutic targets.

A 20-Year Experience with Treatment of Ectopic Ureteroceles

Between 1970 and 1990 a total of 37 patients (female-to-male ratio 3.6:1) was diagnosed and treated at our institution for ectopic ureterocele. Urinary tract infection was the most frequent mode of presentation (59%). Of the patients 54% were less than 3 years old at operation. Transurethral incision of ectopic ureterocele served only as a decompressive procedure for acutely ill infants and was followed with a high incidence (80%) of resultant vesicoureteral reflux. The elective surgical policy was individualized based on renal function and presence of vesicoureteral reflux. Overall results within the various groups were generally satisfactory regarding eradication of urinary tract infections, preservation of renal function and continence or treatment of vesicoureteral reflux. Upper pole heminephrectomy and partial ureterectomy were performed in 14 patients with 3 (21%) requiring reoperation, including only 2 (14%) subsequent reimplantations. Thus, we believe that an expectant approach to the lower urinary tract is well recommended in the majority of the patients with a poorly functioning ipsilateral renal segment. A modified technique of total reconstruction, performing only partial ureterectomy with double barrel reimplantation, was successful in 7 patients.

Sonographic appearances of torsion of the appendix testis and appendix epididymis in children

The most common cause of acute scrotum in prepubertal boys is torsion of the testicular or epididymal appendages. The purpose of this retrospective study was to characterize the features of these lesions as viewed on sonographic (US) and color Doppler US examination.

Prophylactic antibiotic treatment following laparoscopic robot-assisted radical prostatectomy for the prevention of catheter-associated urinary tract infections: did the AUA guidelines make a difference?

We sought to evaluate the effectiveness of the American Urological Association (AUA) antibiotic prophylaxis guidelines in patients undergoing robot-assisted laparoscopic radical prostatectomy (RALP). Our prospective registry database was reviewed for all RALP cases. The following variables were evaluated: age, associated comorbidities, body mass index (BMI), total operative time, length of stay (LOS), prostate weight, pathological grade and stage. Until 11/2011, RALP patients were treated with antibiotics administered in the operating room and continued until urethral catheter removal. Since 11/2011, all patients were treated with a single intravenous dose of Cephalosporin and Aminoglycoside given within 30xa0min of surgical incision. The rate of catheter-associated urinary tract infection (CAUTI) was evaluated in both groups. 229 RALP patients were identified. The first 60 patients (26.2%) were treated according to the old protocol (Group 1) while the remaining 169 (73.8%) were treated according to the new protocol (Group 2). Group match was identified in all categories but LOS. Moreover, LOS was found to be longer in Group 1 compared with Group 2 (5.8 vs. 4.5xa0days, pxa0<xa00.001). CAUTI rate was similar in both groups (8.3 vs. 8.9%, respectively, pxa0=xa00.89). Logistic regression analysis did not demonstrate any association between treatment protocol and potential risk for CAUTI. Therefore, a single preoperative dose of antibiotics does not increase the rate of CAUTI following RALP compared with prolonged antibiotic treatment. Moreover, it was found to be associated with shorter LOS. Complying with the AUA guidelines may reduce morbidity and medical costs.

Bulbocavernosus reflex testing: a preliminary study on the prognostic factors for potency and response to sildenafil citrate after bilateral nerve-sparing radical prostatectomy

ObjectiveErectile dysfunction (ED) following radical prostatectomy is of major concern for both patients and caring physicians. We evaluated the bulbocavernosus reflex latency (BCRL) and amplitude (BCRA) following bilateral nerve-sparing radical retropubic prostatectomy (NS-RRP) to predict the response to sildenafil citrate (SC).MethodsPatients were recruited in our ED clinic following NS-RRP. Exclusion criteria included preoperative significant ED, neurological disease, and nitrates treatment. Patients were defined as non-responders only after four consecutive unsuccessful trials of 100xa0mg SC.ResultsTwenty patients at least 3xa0months after surgery were included in this study. Five patients (25%) regained spontaneous erections, although insufficient for vaginal penetration. All of them had normal BCRL and normal BCRA as well as good response to 100xa0mg SC. Three patients (15%) lacked spontaneous erections and had prolonged BCRL with normal BCRA. This subgroup eventually regained erections using SC. Twelve patients (60%) lacked spontaneous erections and had prolonged BCRL and low BCRA. They failed SC trials and achieved erections using intra-cavernosal injections (ICI) of 10xa0μg PGE1.ConclusionsNeurophysiologic evaluation consisting of BCRL and BCRA was found to be useful in the prediction of the response to SC following bilateral NS-RRP. Patients who do not regain an erection, and have abnormal BCRL and BCRA 6xa0months after surgery, will probably be SC non-responders and may benefit from ICI. A subset of patients with preserved BCRA and prolonged latencies has been shown to have a better chance to respond to SC.

An unusual radiologic appearance of Wilms tumor

a Department of Urology, Tel-Hashomer, Ramat-Gan, Affiliated to Sackler School of Medicine, Tel-Aviv University, Israel Department of Pathology, Tel-Hashomer, Ramat-Gan, Affiliated to Sackler School of Medicine, Tel-Aviv University, Israel c Department of Pediatric Hemato-Oncology. Tel-Hashomer, Ramat-Gan, Affiliated to Sackler School of Medicine, Tel-Aviv University, Israel Unit of Pediatric Imaging, Tel-Hashomer, Ramat-Gan, Affiliated to Sackler School of Medicine, Tel-Aviv University, Israel e The Chaim Sheba Medical Center and Edmond and Lily Safra Childrens Hospital, Tel-Hashomer, Ramat-Gan, Affiliated to Sackler School of Medicine, Tel-Aviv University, Israel

Secondary enuresis and urological manifestations in children with ataxia telangiectasia

BACKGROUNDnAtaxia telangiectasia (AT) is a neurodegenerative cerebellar disorder, caused by mutations in the ATM gene, involved in DNA repair. Radiosensitivity, progressive ataxia, immune deficiency and malignancies, are well known symptoms, but urological manifestations are scarcely described.nnnOBJECTIVEnTo characterize urologic manifestations in a large cohort of AT patients.nnnMETHODSnRetrospective cross-sectional chart study comprising 52 AT patients followed at a National AT Center.nnnRESULTSn25% of the cohort (13 patients/8 males) had urologic symptoms, which presented at 11xa0±xa04.3 years. The most common symptom was secondary enuresis affecting 15% of the patients (8 children/4 males). Incontinence appeared at 8xa0±xa06.2 years of age, and resolved spontaneously within 15xa0±xa08.3 months in 6 patients. It preceded loss of ambulatory capacity by 1-2 years in 7 patients. Lumbosacral MRI were normal (4 children) and urine cultures (all) were negative. Urodynamic evaluation that was performed in only one patient revealed overactive bladder. Additional manifestations were macroscopic hematuria due to bladder telangiectasia in a 12-year-old, and renal cell carcinoma in a 22-year-old. Other manifestations unrelated to AT were neprolithiasis, vesico-ureteral reflux and scrotal pain, each in 1 patient.nnnDISCUSSIONnTransient secondary enuresis is a frequent finding in AT patients, heralding loss of ambulatory capacity, tough its pathophysiological mechanism is largely no understood.

Postoperative Urinary Leakage Following Partial Nephrectomy for Renal Mass: Risk Factors and a Proposed Algorithm for the Diagnosis and Management:

Objectives: To evaluate the current incidence, risk factors, management, and long-term follow-up of urinary leakage following partial nephrectomy, in order to propose an algorithm for diagnosis and evaluation of postoperative urinary leakage. Materials and Methods: The study included 752 patients who underwent elective partial nephrectomies for renal masses between the years 1988 and 2013. Patients’ demographics, clinico-pathologic variables, and operative details were collected retrospectively. The associations between urinary leakage and patients’ variables were assessed by univariate and multivariate analyses. Results: Of the 752 patients, 21 (2.8%) experienced urinary leakage; 4 of the 21 patients with urinary leakage had spontaneous resolution, 1 patient underwent nephrectomy, and 16 patients were treated by retrograde ureteral stents insertion. One of them necessitated insertion of an additional percutaneous nephrostomy and another one deserved concomitant percutaneous drainage of a perirenal urinoma. The average period of time that elapsed from the operation until the insertion of stent was 8.5u2009±u20094.5u2009days. Stents were removed 68u2009±u200920.5u2009days postoperatively. None of the patients had either persistent or repeated leakage. On univariate analysis, hilar renal masses (pu2009<u20090.04) and higher preoperative creatinine levels (pu2009<u20090.01) were found to be associated with higher rates of urinary leakage. None of these variables was significant on a multivariate analysis. Review of the urinary leakage rate over time revealed it has been constantly decreasing over time, from 4% in early cases to 1.3% among the most recent ones. Conclusion: None of the preoperative variables that were examined in this study was significantly associated with increased risk of urinary leakage. However, cumulative surgical experience was associated with lower rates of urinary leakage, suggesting that the decrease in its incidence is related to the improved surgical skills, rather than to differences in tumors’ or patients’ characteristics.