Richard N. Yu

Small-Molecule Inhibition of BRDT for Male Contraception

Summary A pharmacologic approach to male contraception remains a longstanding challenge in medicine. Toward this objective, we explored the spermatogenic effects of a selective small-molecule inhibitor (JQ1) of the bromodomain and extraterminal (BET) subfamily of epigenetic reader proteins. Here, we report potent inhibition of the testis-specific member BRDT, which is essential for chromatin remodeling during spermatogenesis. Biochemical and crystallographic studies confirm that occupancy of the BRDT acetyl-lysine binding pocket by JQ1 prevents recognition of acetylated histone H4. Treatment of mice with JQ1 reduced seminiferous tubule area, testis size, and spermatozoa number and motility without affecting hormone levels. Although JQ1-treated males mate normally, inhibitory effects of JQ1 evident at the spermatocyte and round spermatid stages cause a complete and reversible contraceptive effect. These data establish a new contraceptive that can cross the blood:testis boundary and inhibit bromodomain activity during spermatogenesis, providing a lead compound targeting the male germ cell for contraception. PaperClip

Phase III, Randomized, Open-Label Study of Daily Imatinib Mesylate 400 mg Versus 800 mg in Patients With Newly Diagnosed, Previously Untreated Chronic Myeloid Leukemia in Chronic Phase Using Molecular End Points: Tyrosine Kinase Inhibitor Optimization and Selectivity Study

PURPOSE To evaluate the safety and efficacy of initial treatment with imatinib mesylate 800 mg/d (400 mg twice daily) versus 400 mg/d in patients with newly diagnosed chronic myeloid leukemia in chronic phase. PATIENTS AND METHODS A total of 476 patients were randomly assigned 2:1 to imatinib 800 mg (n = 319) or 400 mg (n = 157) daily. The primary end point was the major molecular response (MMR) rate at 12 months. RESULTS At 12 months, differences in MMR and complete cytogenetic response (CCyR) rates were not statistically significant (MMR, 46% v 40%; P = .2035; CCyR, 70% v 66%; P = .3470). However, MMR occurred faster among patients randomly assigned to imatinib 800 mg/d, who had higher rates of MMR at 3 and 6 months compared with those in the imatinib 400-mg/d arm (P = .0035 by log-rank test). CCyR also occurred faster in the 800-mg/d arm (CCyR at 6 months, 57% v 45%; P = .0146). The most common adverse events were edema, gastrointestinal problems, and rash, and all were more common in patients in the 800-mg/d arm. Grades 3 to 4 hematologic toxicity also occurred more frequently in patients receiving imatinib 800 mg/d. CONCLUSION MMR rates at 1 year were similar with imatinib 800 mg/d and 400 mg/d, but MMR and CCyR occurred earlier in patients treated with 800 mg/d. Continued follow-up is needed to determine the clinical significance of earlier responses on high-dose imatinib.

Treatment of Vesicoureteral Reflux Using Endoscopic Injection of Nonanimal Stabilized Hyaluronic Acid/Dextranomer Gel: Initial Experience in Pediatric Patients by a Single Surgeon

OBJECTIVE. Endoscopic injection of nonanimal stabilized hyaluronic acid/dextranomer gel is an increasingly recognized treatment option for vesicoureteral reflux. The procedure is minor compared with open surgery and, when successful, avoids the need for long-term antibiotic prophylaxis. We present data from our first 18 months using nonanimal stabilized hyaluronic acid/dextranomer gel to treat children with vesicoureteral reflux. PATIENTS AND METHODS. Pediatric patients aged ≤15 years with uncomplicated primary vesicoureteral reflux were recruited for endoscopic treatment with nonanimal stabilized hyaluronic acid/dextranomer gel. A follow-up voiding cystourethrogram was scheduled at ≥2 weeks after treatment, and vesicoureteral reflux resolution was defined as grade 0. Repeat nonanimal stabilized hyaluronic acid/dextranomer gel treatment was offered to patients with persistent vesicoureteral reflux. RESULTS. Of 120 patients treated, 6 were lost to follow-up, and 7 were yet to undergo posttreatment voiding cystourethrogram. The 107 remaining patients (efficacy population) had a mean age of 4.1 years (range: 0.5–15.0), and the median reflux grade was 2 (range: 1–5). The mean time to follow-up voiding cystourethrogram was 9.7 weeks (range: 2–26). Vesicoureteral reflux was resolved in 82.2% of patients and 86.9% of ureters after initial endoscopic treatment with nonanimal stabilized hyaluronic acid/dextranomer gel. The overall reflux resolution rate for patients increased to 90.7% after a second treatment in 14 patients. Two patients reported postoperative flank pain, although this was mild and transient in nature. No other adverse events were reported. No patients underwent open surgery for vesicoureteral reflux. CONCLUSIONS. Endoscopic treatment with nonanimal stabilized hyaluronic acid/dextranomer gel is effective in a high proportion of children with vesicoureteral reflux and, in our opinion, may be considered as a first-line treatment option.

All-Trans Retinoic Acid Directs Urothelial Specification of Murine Embryonic Stem Cells via GATA4/6 Signaling Mechanisms

The urinary bladder and associated tract are lined by the urothelium, a transitional epithelium that acts as a specialized permeability barrier that protects the underlying tissue from urine via expression of a highly specific group of proteins known as the uroplakins (UP). To date, our understanding of the developmental processes responsible for urothelial differentiation has been hampered due to the lack of suitable models. In this study, we describe a novel in vitro cell culture system for derivation of urothelial cells from murine embryonic stem cells (ESCs) following cultivation on collagen matrices in the presence all trans retinoic acid (RA). Upon stimulation with micromolar concentrations of RA, ESCs significantly downregulated the pluripotency factor OCT-4 but markedly upregulated UP1A, UP1B, UP2, UP3A, and UP3B mRNA levels in comparison to naïve ESCs and spontaneously differentiating controls. Pan-UP protein expression was associated with both p63- and cytokeratin 20-positive cells in discrete aggregating populations of ESCs following 9 and 14 days of RA stimulation. Analysis of endodermal transcription factors such as GATA4 and GATA6 revealed significant upregulation and nuclear enrichment in RA-treated UP2-GFP+ populations. GATA4−/− and GATA6−/− transgenic ESC lines revealed substantial attenuation of RA-mediated UP expression in comparison to wild type controls. In addition, EMSA analysis revealed that RA treatment induced formation of transcriptional complexes containing GATA4/6 on both UP1B and UP2 promoter fragments containing putative GATA factor binding sites. Collectively, these data suggest that RA mediates ESC specification toward a urothelial lineage via GATA4/6–dependent processes.

Adult care of children from pediatric urology.

PURPOSE In this article we highlight the difference, from established adult urology, in required approach to the care of adolescents and young adults presenting with the long-term consequences of the major congenital anomalies of the genitourinary tract. We review some abnormalities of the kidneys, progressive renal failure and disorders of bladder function from which general conclusions can be drawn. MATERIALS AND METHODS The published literature was reviewed and augmented with material from our institutional databases. For renal function the CAKUT (congenital abnormalities of the kidney and urinary tract) database at University College London Hospitals was used, which includes 101 young adult patients with CAKUT in whom the urinary tract has not been diverted or augmented. For bladder function some data are from patient records at Boston Childrens Hospital. RESULTS Adolescents who grow up with the burden of a major congenital anomaly have an overwhelming desire to be normal. Many achieve high levels of education and occupy a wide range of employment scenarios. Babies born with damaged kidneys will usually experience improvement in renal function in the first 3 years of life. Approximately 50% of these cases will remain stable until puberty, after which half of them will experience deterioration. Any urologist who treats such patients needs to test for proteinuria as this is a significant indicator of such deterioration. In its absence, the urologist must have a reasonable strategy for seeking a urological cause. The most effective management for nephrological renal deterioration is with angiotensin converting enzyme inhibitors, which slow but do not prevent end stage renal failure. Renal deterioration is generally slower in these patients than in those with other forms of progressive renal disease. The bladder is damaged by obstruction or by functional abnormalities such as myelomeningocele. Every effort should be made to stabilize or reconstruct the bladder in childhood. A dysfunctional bladder is associated with or causes renal damage in utero, but continued dysfunction will cause further renal damage. Bladder function often changes in puberty, especially in boys with posterior urethral valves who may experience high pressure chronic retention. Dysfunction is managed with antimuscarinic drugs, clean intermittent self-catheterization and intestinal augmentation. Adult urologists must be able to manage the long-term problems associated with these treatments. CONCLUSIONS Pediatric conditions requiring management in adolescence are rare but have major, lifelong implications. Their management requires a broad knowledge of pediatric and adult urology, and could well be a specialty in its own right. Therefore, adult urologists must remain aware of the conditions, the problems that they may encounter and the special management required for these patients to live normal lives.

Urological Complications and Vesicoureteral Reflux Following Pediatric Kidney Transplantation

PURPOSE Ureteral complications of renal transplantation can dramatically impact renal outcomes. We studied whether complications are associated with preexisting genitourinary pathology or transplant using a deceased donor allograft. MATERIALS AND METHODS We retrospectively reviewed all patients undergoing renal transplantation at our institution between 2000 and 2010. We abstracted patient demographic details, donor type (living vs deceased), end-stage renal disease etiology, reimplant technique, stent use, preoperative and postoperative imaging, history of lower genitourinary pathology and postoperative complication management. RESULTS A total of 211 kidneys were transplanted into 206 patients (mean age 13.7 years, mean followup 4.6 years). Most patients (89%) underwent extravesical ureteroneocystostomy without stenting (97%), with roughly half (47%) of transplants being from living donors. Preexisting urological pathology was present in 34% of cases. Postoperative obstruction or extravasation occurred in 16 cases (7.6%), of which 15 were acute. Complications were not associated with donor type, preexisting urological pathology other than posterior urethral valves, surgical technique, etiology of end-stage renal disease or patient age. However, posterior urethral valves or other preexisting genitourinary pathology was not associated with an increased likelihood of genitourinary complications. Posterior urethral valves were associated with development of postoperative vesicoureteral reflux (OR 6.7, p = 0.004) but were not associated with stent placement, surgical technique, donor type or etiology of end-stage renal disease. CONCLUSIONS Patients with posterior urethral valves undergoing renal transplantation are at increased risk for postoperative vesicoureteral reflux but not for other acute surgical complications. There is no association between donor type, etiology of end-stage renal disease, surgical technique or patient age and increased complications.

Stem Cells: A Review and Implications for Urology

OBJECTIVE The promise of stem cells is to provide a source of non-diseased material for the generation of patient-specific cells or tissue for replacement and reconstruction. This review will provide a broad perspective on stem cell research, from the sentinel discoveries to recent developments, and also discuss translational implications. METHODS We performed internet-based Pubmed database searches to identify recent articles and review papers pertaining to stem cell research and urologic applications. RESULTS Depending on their source, stem cells have a varied capacity to self-renew and divide and to differentiate into a desired phenotype. Pluripotent stem cells can potentially be differentiated into any cell type and multipotent stem cells are variably lineage restricted. In the urologic literature, stem cell derived smooth muscles have been produced and may be useful for tissue-engineered constructs. CONCLUSIONS The future of reconstructive surgery will surely incorporate a number of these stem cell based technologies in revolutionary ways that may improve and extend lives. However, the ultimate utility and clinical applicability of the different types of stem cells will depend on a complex synthesis of further basic research, future clinical trials, and ethical and regulatory reconcilement.

Barriers to Fertility Preservation in Male Adolescents With Cancer: It's Time for a Multidisciplinary Approach that Includes Urologists

m i Acancer diagnosis can be devastating news for a child and his or her family. Fortunately, advances in the treatment of childhood cancers have resulted in 5-year survival rates close to 80%. Late effects of cancer treatment, such as infertility, have thus become an active area of research; a recent study found that male cancer survivors were only half as likely to sire a pregnancy as healthy males. Surgery, chemotherapy, nd radiation exposure can all result in temporary or ermanent damage to sperm production, and fertility may e compromised soon after treatment has begun. In ddition to preserving reproductive capacity, sperm cryoreservation in young adults appears to have other benfits; for example, sperm banking has been reported to elp young men endure the emotional battle against ancer. For all of these reasons, boys who are able to roduce a semen sample are encouraged to bank sperm efore starting oncological treatment. Fertility preservation has been identified as a priority or practitioners, patients, and parents. However, a miority of patients actually pursue sperm banking, and any barriers appear to exist. One study showed that lthough 51% of male cancer patients showed interest in aving children in the future and were given a choice to ank, only 24% of them actually banked sperm. Factors uch as socioeconomic status and religious concerns have been reported as barriers, but the data are inconsistent and these variables are difficult to change. In comparison, the role of the practitioner and the quality of counseling provided have repeatedly been reported as the most significant factors in the decision to bank sperm, particularly in adolescents who may have

Semen analysis in adolescent cancer patients prior to bone marrow transplantation: when is it too late for fertility preservation?

Sperm banking is an effective method of fertility preservation in adolescent boys with cancer but is strikingly underutilized, partly due to inconsistencies in fertility counseling and unclear guidelines regarding who should bank sperm. Patients undergoing bone marrow transplantation (BMT) are of particular interest given the high risk of infertility in this population.

Klinefelter Syndrome Are We Missing Opportunities for Early Detection

Klinefelter syndrome is a common condition that remains underdiagnosed, particularly prior to adulthood. Early detection could prevent morbidity and mortality, but the classic phenotype of small testes and tall stature may not be apparent until adolescence, and there is minimal guidance regarding whom to screen. We performed a retrospective study at Boston Children’s Hospital in patients with the ICD-9 code for “Klinefelter syndrome” diagnosed prior to age 20 years, and determined age and reason for diagnosis, karyotype, heights, and comorbid conditions. Eighty percent had a 47,XXY karyotype, of whom half were diagnosed at age 11 to 19 years. The most common comorbidities were neurocognitive, including learning disabilities (67%), psychosocial problems (33%), and attention deficit disorder (27%). Subjects were only slightly taller than average in childhood (height standard deviation score = 0.64). These data show that Klinefelter syndrome is associated with long-standing comorbidities that frequently remain under-recognized; a karyotype should be considered in boys with neurocognitive problems.