Long-term sexual health outcomes in men with classic bladder exstrophy.

OBJECTIVES: To identify the long-term sexual health outcomes and relationships in men born with classic bladder exstrophy (CBE). MATERIALS AND METHODS: A prospectively maintained institutional database comprising 1248 patients with exstrophy-epispadias was used. Men aged ≥18 years with CBE were included in the study. A 42-question survey was designed using a combination of demographic information and previously validated questionnaires. RESULTS: A total of 215 men met the inclusion criteria, of whom 113 (53%) completed the questionnaire. The mean age of the respondents was 32 years. Ninety-six (85%) of the respondents had been sexually active in their lifetime, and 66 of these (58%) were moderately to very satisfied with their sex life. The average Sexual Health Inventory for Men score was 19.8. All aspects of assessment using the Penile Perception Score questionnaire were on average between 'very dissatisfied' and 'satisfied'. Thirty-two respondents (28%) had attempted to conceive with their partner. Twenty-three (20%) were successful in conceiving, while 31 (27%) reported a confirmed fertility problem. A total of 31 respondents (27%) reported undergoing a semen analysis or post-ejaculatory urine analysis. Of these, only four respondents reported azoospermia. CONCLUSION: Patients with CBE have many of the same sexual and relationship successes and concerns as the general population. This is invaluable information to give to both the parents of boys with CBE, and to the boys themselves as they transition to adulthood.

A Retrospective Analysis of the Effect on Survival of Time from Diagnosis to Neoadjuvant Chemotherapy to Cystectomy for Muscle Invasive Bladder Cancer.

PURPOSE: We determine the impact of the timing of radical cystectomy from the diagnosis of muscle invasive bladder cancer on survival in patients also treated with neoadjuvant chemotherapy. MATERIALS AND METHODS: We performed a retrospective chart review of consecutive patients with muscle invasive bladder cancer who received neoadjuvant chemotherapy followed by cystectomy between 1996 and 2014 at a single institution. Cox proportional hazards regression models were used to investigate the effect of treatment time intervals on overall survival. Three treatment intervals were analyzed for survival impact, from diagnosis of muscle invasive bladder cancer to initiation of neoadjuvant chemotherapy, from initiation of neoadjuvant chemotherapy to cystectomy and from diagnosis to cystectomy. Other pretreatment and posttreatment clinicopathological parameters were also analyzed. RESULTS: Median time from the diagnosis of muscle invasive bladder cancer to radical cystectomy was 28 weeks. Cystectomy performed less than 28 weeks from the diagnosis did not result in significant improvement in overall survival outcomes (HR 0.68, 95% CI 0.28-1.63, p=0.388). Neither the timing of neoadjuvant chemotherapy initiation from diagnosis (median 6 weeks) nor the timing of cystectomy from neoadjuvant chemotherapy initiation (median 22 weeks) was associated with survival. Patient age, variant histology, extravesical and/or lymph node involvement (T3-4 and/or N1 or greater) were significantly associated with survival. CONCLUSIONS: The timing of radical cystectomy in relation to muscle invasive bladder cancer diagnosis date does not significantly impact overall survival in patients with muscle invasive bladder cancer receiving neoadjuvant chemotherapy.

Blood Transfusion is Associated with Increased Perioperative Morbidity and Adverse Oncologic Outcomes in Bladder Cancer Patients Receiving Neoadjuvant Chemotherapy and Radical Cystectomy.

PURPOSE: Perioperative blood transfusion (PBT) has been inconsistently associated with adverse outcomes. Bladder cancer patients are unique as they frequently undergo neoadjuvant chemotherapy (NAC) with resulting immunosuppression, which may be exacerbated by transfusion-related immunomodulation. We examined the effect of leukoreduced PBT on oncologic outcomes and perioperative morbidity in radical cystectomy (RC) patients who received NAC, quantifying exposure with a novel dose-index variable. METHODS: The Johns Hopkins Radical Cystectomy database was queried for patients who had undergone NAC followed by RC from 2010 to 2013. Overall, 119 patients had available PBT and survival data. A multivariable Cox model evaluated risk factors, including pathologic stage, Charlson Comorbidity Index, age, race, year of surgery, surgical margin status, PBT, and preoperative hemoglobin for bladder cancer-specific survival (CSS) and overall survival (OS). Logistic regression models determined factors that were independently associated with perioperative morbidity. RESULTS: Median follow-up was 7.8 months (range 0.2-41.8), and during follow-up there were 25 deaths and 21 cancer deaths. PBT significantly predicted OS (hazard ratio [HR] 1.26, 95 % confidence interval [CI] 1.07-1.49; p = 0.005), CSS (HR 1.32, 95 % CI 1.11-1.57; p = 0.002), and morbidity (odds ratio [OR] 1.67, 95 % CI 1.26-2.21; p = 0.004) in univariate analyses. In multivariable models, PBT was significantly associated with morbidity (OR 1.77, 95 % CI 1.30-2.39; p = 0.0002), but not OS or CSS. Intraoperative transfusion was associated with decreased OS and CSS, and increased morbidity, whereas postoperative transfusion was only associated with increased morbidity. CONCLUSIONS: Intraoperative blood transfusion was associated with increased perioperative morbidity and worsened OS and CSS in patients undergoing RC who had NAC. Although PBT may be life-saving in certain patients, a restrictive transfusion strategy may improve outcomes.

Infectious complications in transfused patients after radical cystectomy.

INTRODUCTION: Infectious complications are common after radical cystectomy (RC), and allogeneic blood transfusions may increase infection risk by an immunosuppressive effect. While it has been suggested that perioperative blood transfusion (PBT) may be associated with adverse oncologic outcomes after RC, no large analyses have assessed whether PBT increases the risk of perioperative infection after RC. MATERIALS AND METHODS: We used the Nationwide Inpatient Sample (1998 to 2011) to study the rate of PBT during RC for bladder cancer and identify infectious complications. We compared rates of infectious complications in patients who did and did not receive PBT and developed a multivariable model to assess the independent risk of infectious complication associated with PBT controlling for age, year of surgery, obesity, chronic kidney disease, comorbidity score, and type of urinary diversion. RESULTS: We identified 126,454 RCs performed during the study period. A total of 34,203 (27%) received a PBT. The use of PBT increased over the study period, from 18.4% in 1998 to 31.6% in 2011 (p < 0.0001). Patients who received a PBT had an increased risk of perioperative infectious complications [36.7% versus 27.7%, unadjusted OR (95% CI) = 1.51 (1.43-1.60), p < 0.0001]. After adjusting for potential confounders, PBT remained an independent predictor of infectious complications [adjusted OR (95% CI) = 1.46 (1.38-1.55), p < 0.0001]. CONCLUSIONS: This analysis provides strong observational evidence that PBT is associated with an increased risk of perioperative infectious complications, which may be secondary to transfusion-related immunomodulation. Urologists should aggressively pursue blood conservation strategies and adhere to evidence-based restrictive transfusion thresholds, particularly given the rising rate of PBT.

Bacillus Calmette-Guérin immunotherapy for genitourinary cancer.

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: The administration of Bacillus Calmette-Guérin (BCG) immunotherapy has become the standard of care for high-grade non-muscle invasive bladder cancer (NMIBC) and carcinoma in-situ (CIS) in terms of prevention of recurrence and progression. While most agree on a 6 week induction cycle, various maintenance schedules (if any at all) have been implemented without a unifying consensus. This review assesses the historical emergence of BCG immunotherapy, beginning with its discovery as a vaccinatin for tuberculosis to its effect on the host immune system and potential therapeutic benefits for various oncologic conditions. The data establishing BCG immunotherapy as the standard of care for high-grade NMIBC and CIS over other bladder instillation modalities is presented in addition to the effect maintenance BCG therapy has on sustaining the immuno-protective effect. Bacillus Calmette-Guérin (BCG) immunotherapy is currently the most effective treatment of non-muscle invasive bladder cancer and one of the most successful applications of immunotherapy to the treatment of cancer. This review summarises the history and development of BCG as a modern cancer treatment, appraises current optimal application of BCG immunotherapy in bladder cancer, discusses promising new therapies closely related to BCG, and briefly explores the possibility that BCG or related treatments may have an application in other urological malignancies. BCG is a nonspecific stimulant to the reticuloendothelial system and induces a local inflammatory response with the infiltration of granulocytes followed by macrophages and lymphocytes, particularly helper T cells. The initial BCG controlled trial showed a statistically significant reduction in tumour recurrence and found the advantage increased with duration of follow-up. Similar results were reported in much higher risk patients in an independent concurrent study. Follow-up suggested that a single 6-week course of intravesical BCG provided long-term protection (up to 10 years) from tumour recurrence and even reduced disease progression. While induction BCG (six weekly instillations) reduced recurrence, progression and mortality at 10 years, this advantage was lost by 15 years, and patients remained at high risk for progression without the use of maintenance BCG. In a meta-analysis by the Cochrane group, induction BCG was found to be markedly superior to mitomycin C in high-risk patients but not in low-risk patients. Additionally, the National Comprehensive Cancer Network guidelines lists the use of intravesical BCG as preferred therapy, citing Category 1 data for high-grade Ta, all T1, and any Tis tumours. Maintenance BCG therapy may be the most important advance in BCG treatment of bladder cancer since the initial introduction. The risk of tumour recurrence and disease progression is life-long in most patients, but the immune stimulation induced by BCG wanes with time. Logarithmic dose reduction of BCG in patients with increasing side-effects will typically prevent escalation of toxicity. Simple dose reduction, appropriate antibiotics, and understanding treatment contraindications have greatly increased the safety of BCG. The 3-week maintenance schedule for 3 years has been evaluated in randomised clinical trials and appears to be the current optimal treatment. With the success achieved in bladder cancer and the relative safety and economy of BCG, consideration should be given to further research for its effectiveness in other genitourinary malignancies.

Diagnostic value of routine chest radiography in febrile, neutropenic children for early detection of pneumonia and mould infections.

BACKGROUND: Despite recent studies failing to demonstrate the value of routine chest radiography (CXR) in the initial evaluation of the febrile neutropenic patient with cancer, this screening test is advocated by some experts. We evaluated the benefits of CXR for early diagnosis of pulmonary infection at St. Jude Children's Research Hospital (SJCRH) with emphasis on early recognition of mould infections. PATIENTS AND METHODS: We reviewed the courses of 200 consecutive febrile neutropenic pediatric patients to determine if routine CXR at initial evaluation was useful in the identification of clinically occult pneumonia. We also reviewed all cases of proven or probable mould infections from the opening of SJCRH in 1962 until 1998 when routine CXR was no longer practiced in our institution to identify cases that were first recognized by routine CXR. RESULTS: Of 200 febrile neutropenic patients, pulmonary abnormalities consistent with pneumonia were detected by routine CXR in only five patients without pulmonary signs or symptoms. In only one case was a change in management considered. Of the 70 patients with pulmonary mould infection identified from 1962 to 1998, routine CXR was performed in 45 patients at the onset of a febrile, neutropenic episode in which a mould infection was diagnosed. Routine CXR was pivotal in the recognition of the mould infection in only two cases over this 36-year period. CONCLUSION: CXR is warranted in the evaluation of the newly febrile neutropenic pediatric oncology patient only when respiratory signs or symptoms are present.

Patient-Reported Impact of Pelvic Organ Prolapse on Continence and Sexual Function in Women With Exstrophy-Epispadias Complex.

OBJECTIVE: This study aimed to characterize long-term urogynecologic issues of women with a history of bladder exstrophy and pelvic organ prolapse (POP) and to assess the impact of POP repair on continence and sexual function. DESIGN: Patient demographics and surgical history related to exstrophy and POP were collected through chart review. Patient perceptions regarding sexual function, urinary continence, and quality of life were assessed through Web-based administration of validated questionnaires: International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form and POP-Urinary Incontinence Sexual Questionnaire. SETTING: Maryland, United States. PARTICIPANTS: Review of a single-institution exstrophy-epispadias complex database resulted in 25 adult female patients with a history of POP treated at the authors' institution. Eleven patients participated and were included in the analysis. MAIN OUTCOME MEASURES: Urinary continence and sexual function. RESULTS: All participants underwent surgical repair for prolapse, with 7 (63.6%) experiencing unsuccessful initial repair and subsequent recurrence. Median total number of POP repairs was 2.5 (1-4). After correction of POP, patients reported a median improvement in International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form scores of 11 (21 to -1) of 21 and in POP-Urinary Incontinence Sexual Questionnaire scores of 9.5 (6.5-33.0) of 48.0. With regard to urinary continence, 6 (54.5%) patients presently reported no incontinence, 3 (27.3%) reported mild incontinence, and 2 (18.2%) reported continuous incontinence. CONCLUSIONS: Pelvic organ prolapse poses significant reductions in quality of life for women born with exstrophy, with effects on urinary continence and sexual function. Identification and correction of prolapse seems to result in notable improvements in the lives of these patients.

Profound Hematuria in a Toddler Yields an Unusual Diagnosis.

Herein we present a rare case of profound recurrent gross hematuria in a young child with no known predisposing event. She was eventually diagnosed with a large lymphovascular malformation of the bladder. She underwent multiple unsuccessful attempts at embolization before eventual curative partial cystectomy.

The ratio of CD8 to Treg tumor-infiltrating lymphocytes is associated with response to cisplatin-based neoadjuvant chemotherapy in patients with muscle invasive urothelial carcinoma of the bladder.

INTRODUCTION: Randomized controlled trials of platinum-based neoadjuvant chemotherapy (NAC) for bladder cancer have shown that patients who achieve a pathologic response to NAC exhibit 5 y survival rates of approximately 80-90% while NAC resistant (NR) cases exhibit 5 y survival rates of approximately 30-40%. These findings highlight the need to predict who will benefit from conventional NAC and the need for plausible alternatives. METHODS: The pre-treatment biopsy tissues from a cohort of 41 patients with muscle invasive bladder who were treated with NAC were incorporated in tissue microarray and immunohistochemistry for PD-L1, CD8, and FOXP3 was performed. Percentage of PD-L1 positive tumor cells was measured. Tumor-infiltrating lymphocytes (TIL) densities, along with CD8 and Treg-specific TILs, were measured. RESULTS: TIL density was strongly correlated with tumor PD-L1 expression, consistent with the mechanism of adaptive immune resistance in bladder cancer. Tumor cell PD-L1 expression was not a significant predictor of response. Neither was the CD8 nor Treg TIL density associated with response. Intriguingly though, the ratio of CD8 to Treg TIL densities was strongly associated with response (p = 0.0003), supporting the hypothesis that the immune system plays a role in the response of bladder cancer to chemotherapy. DISCUSSION: To our knowledge, this is the first report in bladder cancer showing that the CD8 to Treg TIL density in the pre-treatment tissues is predictive for conventional NAC response. These findings warrant further investigations to both better characterize this association in larger cohorts and begin to elucidate the underlying mechanism(s) of this phenomenon.

The Tunica Vaginalis Flap as an Adjunct to Epispadias Repair: A Preliminary Report.

OBJECTIVE: To report our preliminary institutional experience of incorporating a tunica vaginalis flap (TVF) as an adjunct into primary or secondary epispadias repair. PATIENTS AND METHODS: A prospectively maintained institutionally approved database of exstrophy-epispadias complex patients was used to identify and retrospectively review male patients who underwent epispadias repair from September 2010 to October 2014 at the authors' institution. Patients who underwent epispadias repair with TVF were identified and their clinical outcomes were measured. RESULTS: A total of 49 male patients were identified as meeting inclusion criteria, of which 15 (2 isolated epispadias, 13 classic bladder exstrophy) underwent epispadias repair incorporating a TVF. Median age at time of repair was 12 months (interquartile range [IQR] 10-15.5). A median of 4 layers (IQR 4-5) was incorporated into each repair closure, applying EVICEL Fibrin Sealant as an additional layer in all patients. All patients received preoperative testosterone injection therapy of 2 mg/kg 5 and 2 weeks before surgery for penile growth. There were no intraoperative complications. Median follow-up of 19 months (IQR 12-23) revealed 5 patients who underwent epispadias revision, 3 (20%) of which developed a urethrocutaneous fistula. All patients had a successful repair without recurrence. CONCLUSION: The authors have found the utilization of a TVF with epispadias repairs to be beneficial but no better than the repair with our routine soft-tissue coverage in primary epispadias repair. However, in patients presenting with complex anatomy and limited tissue reserves, a TVF is an important adjunct to epispadias repair and/or revision and may lead to improved outcomes.

Cystolitholapaxy in Ileal Conduit.

Urolithiasis is a common complication of surgically treated bladder exstrophy. We report the case of a 43-year-old woman with a history of exstrophy, cystectomy, and ileal conduit urinary diversion presenting with a large calculus at the stomal neck of her conduit in the absence of a structural defect.

Identification and Validation of Protein Biomarkers of Response to Neoadjuvant Platinum Chemotherapy in Muscle Invasive Urothelial Carcinoma.

BACKGROUND: The 5-year cancer specific survival (CSS) for patients with muscle invasive urothelial carcinoma of the bladder (MIBC) treated with cystectomy alone is approximately 50%. Platinum based neoadjuvant chemotherapy (NAC) plus cystectomy results in a marginal 5-10% increase in 5-year CSS in MIBC. Interestingly, responders to NAC (

Gemcitabine and cisplatin neoadjuvant chemotherapy for muscle-invasive urothelial carcinoma: Predicting response and assessing outcomes.

PURPOSE: To evaluate gemcitabine-cisplatin (GC) neoadjuvant cisplatin-based chemotherapy (NAC) for pathologic response (pR) and cancer-specific outcomes following radical cystectomy (RC) for muscle-invasive bladder cancer and identify clinical parameters associated with pR. MATERIALS AND METHODS: We studied 150 consecutive cases of muscle-invasive bladder cancer that received GC NAC followed by open RC (2000-2013). A cohort of 121 patients treated by RC alone was used for comparison. Pathologic response and cancer-specific survival (CSS) were compared. We created the Johns Hopkins Hospital Dose Index to characterize chemotherapeutic dosing regimens and accurately assess sufficient neoadjuvant dosing regarding patient tolerance. RESULTS: No significant difference was noted in 5-year CSS between GC NAC (58%) and non-NAC cohorts (61%). The median follow-up was 19.6 months (GC NAC) and 106.5 months (non-NAC). Patients with residual non-muscle-invasive disease after GC NAC exhibit similar 5-year CSS relative to patients with no residual carcinoma (P = 0.99). NAC pR (≤ pT1) demonstrated improved 5-year CSS rates (90.6% vs. 27.1%, P < 0.01) and decreased nodal positivity rates (0% vs. 41.3%, P<0.01) when compared with nonresponders (≥ pT2). Clinicopathologic outcomes were inferior in NAC pathologic nonresponders when compared with the entire RC-only-treated cohort. A lower pathologic nonresponder rate was seen in patients tolerating sufficient dosing of NAC as stratified by the Johns Hopkins Hospital Dose Index (P = 0.049), congruent with the National Comprehensive Cancer Network guidelines. A multivariate classification tree model demonstrated 60 years of age or younger and clinical stage cT2 as significant of NAC response (P< 0.05). CONCLUSIONS: Pathologic nonresponders fare worse than patients proceeding directly to RC alone do. Multiple predictive models incorporating clinical, histopathologic, and molecular features are currently being developed to identify patients who are most likely to benefit from GC NAC.

Multicenter assessment of neoadjuvant chemotherapy for muscle-invasive bladder cancer.

BACKGROUND: The efficacy of neoadjuvant chemotherapy (NAC) for muscle-invasive bladder cancer (BCa) was established primarily with methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC), with complete response rates (pT0) as high as 38%. However, because of the comparable efficacy with better tolerability of gemcitabine and cisplatin (GC) in patients with metastatic disease, GC has become the most commonly used regimen in the neoadjuvant setting. OBJECTIVE: We aimed to assess real-world pathologic response rates to NAC with different regimens in a large, multicenter cohort. DESIGN, SETTING, AND PARTICIPANTS: Data were collected retrospectively at 19 centers on patients with clinical cT2-4aN0M0 urothelial carcinoma of the bladder who received at least three cycles of NAC, followed by radical cystectomy (RC), between 2000 and 2013. INTERVENTION: NAC and RC. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome was pathologic stage at cystectomy. Univariable and multivariable analyses were used to determine factors predictive of pT0N0 and ≤pT1N0 stages. RESULTS AND LIMITATIONS: Data were collected on 935 patients who met inclusion criteria. GC was used in the majority of the patients (n=602; 64.4%), followed by MVAC (n=183; 19.6%) and other regimens (n=144; 15.4%). The rates of pT0N0 and ≤pT1N0 pathologic response were 22.7% and 40.8%, respectively. The rate of pT0N0 disease for patients receiving GC was 23.9%, compared with 24.5% for MVAC (p=0.2). There was no difference between MVAC and GC in pT0N0 on multivariable analysis (odds ratio: 0.89 [95% confidence interval, 0.61-1.34]; p=0.6). CONCLUSIONS: Response rates to NAC were lower than those reported in prospective randomized trials, and we did not discern a difference between MVAC and GC. Without any evidence from randomized prospective trials, the best NAC regimen for invasive BCa remains to be determined. PATIENT SUMMARY: There was no apparent difference in the response rates to the two most common presurgical chemotherapy regimens for patients with bladder cancer.

Nonspecific Presentation of a Multiloculated Prostatic Abscess After Transurethral Prostatic Biopsy for Elevated Prostate-specific Antigen Level.

Prostate postbiopsy infectious complications typically present in the form of prostatitis and uncommonly urosepsis. Prostatic abscesses are generally found after multiple bouts of prostatitis and are associated with a clinically septic picture requiring intensive care unit admission and resuscitation. We report the case of a 65-year-old man who presented with prostatic abscess in the setting of nonspecific urinary symptoms after transrectal ultrasonography-guided prostate biopsy. At 4-month follow-up, he is currently free of disease with undetectable prostate-specific antigen level and negative imaging.

Correction: Paraventricular Nucleus Sim1 Neuron Ablation Mediated Obesity Is Resistant to High Fat Diet.

[This corrects the article DOI: 10.1371/journal.pone.0081087.].

The utility of an extensive postchemotherapy staging evaluation in patients receiving neoadjuvant chemotherapy for bladder cancer.

OBJECTIVE: To assess the utility of an extensive restaging examination performed after the completion of neoadjuvant chemotherapy (NAC) but before radical cystectomy (RC) in the management of patients with advanced bladder cancer. METHODS: We studied 62 patients who underwent NAC with the intent of proceeding to consolidative RC. A restaging examination, including endoscopic and bimanual examination, as well as cross-sectional imaging of the abdomen and pelvis, was performed after chemotherapy. The impact of restaging on clinical management was determined. In patients proceeding to RC, the degree of correlation between clinical stage (at diagnosis vs on restaging) and pathologic stage was determined. RESULTS: Restaging altered the treatment course in 6 patients (9.7%) in whom RC was not performed because of restaging findings. An additional 56 patients (90.3%) proceeded to RC. In these patients, compared with clinical stage at diagnosis, the postchemotherapy clinical stage correlated more strongly with pathologic stage (κ = 0.02 vs 0.17). On multivariate analysis, diagnostic clinical stage was not associated with pathologic stage (P = .85), whereas postchemotherapy clinical stage was strongly predictive of pathologic stage (P <.01). CONCLUSION: An extensive restaging examination altered treatment strategy in a small, but clinically significant subset of patients treated with NAC for bladder cancer. Furthermore, restaging allowed for more accurate prediction of pathologic stage after RC, thereby improving assessment of patient prognosis. Consideration should be given to incorporating a restaging evaluation into the standard management paradigm for bladder cancer.

Paraventricular nucleus Sim1 neuron ablation mediated obesity is resistant to high fat diet.

Single minded 1 (SIM1) is a transcription factor involved in brain patterning and control of energy balance. In humans, haploinsufficiency of SIM1 causes early-onset obesity. Mice deficient in the homologous gene, SIM1, also exhibit early onset obesity and increased sensitivity to a high fat diet. SIM1 is expressed in several areas of the brain implicated in control of energy balance including the paraventricular nucleus (PVN), the supraoptic nucleus (SON), the medial amygdala and nucleus of the lateral olfactory tract. We have previously shown that mice with global Sim1 neuron ablation exhibit obesity with hyperphagia as the primary defect. The PVN has a critical role in feeding and in high-fat appetite, thus, we sought to determine the effect of Sim1 neuron ablation limited to the PVN. We achieved PVN-SIM1 limited ablation through stereotactic injection of diphtheria toxin into the PVN of Sim1Cre-iDTR mice. The specificity of this ablation was confirmed by immunohistochemistry and quantitative real time PCR of the PVN, supraoptic nucleus and the amygdala. Mice with PVN Sim1 neuron ablation, similar to mice with global Sim1 neuron ablation, exhibit early onset obesity with hyperphagia as the primary defect. However, PVN-Sim1 neuron ablated mice have a decreased response to fasting-induced hyperphagia. Consistent with this decrement, PVN-Sim1 neuron ablated mice have a decreased hyperphagic response to PVN injection of agouti-related peptide (AgRP). When PVN-Sim1 neuron ablated mice are placed on a high fat diet, surprisingly, their intake decreases and they actually lose weight. When allowed ad lib access to high fat diet and normal chow simultaneously, PVN-Sim1 neuron ablated mice exhibit overall decreased intake. That is, in PVN-Sim1 neuron ablated mice, access to fat suppresses overall appetite.

Ablation of Sim1 neurons causes obesity through hyperphagia and reduced energy expenditure.

Single-minded 1 (Sim1) is a transcription factor necessary for development of the paraventricular nucleus of the hypothalamus (PVH). This nucleus is a critical regulator of appetite, energy expenditure and body weight. Previously we showed that Sim1(+/-) mice and conditional postnatal Sim1(-/-) mice exhibit hyperphagia, obesity, increased linear growth and susceptibility to diet-induced obesity, but no decrease in energy expenditure. Bilateral ablation of the PVH causes obesity due to hyperphagia and reduced energy expenditure. It remains unknown whether Sim1 neurons regulate energy expenditure. In this study, Sim1cre mice were bred to homozygous inducible diphtheria toxin receptor (iDTR) mice to generate mice expressing the simian DTR in Sim1 cells. In these mice, Sim1 neuron ablation was performed by intracerebroventricular (ICV) injection of diphtheria toxin. Compared to controls, mice with Sim1 neuron ablation became obese (with increased fat mass) on a chow diet due to increased food intake and reduced energy expenditure. In post-injection mice, we observed a strong inverse correlation between the degree of obesity and hypothalamic Sim1 expression. The reduction in baseline energy expenditure observed in these mice was accompanied by a reduction in activity. This reduction in activity did not fully account for the reduced energy expenditure as these mice exhibited decreased resting energy expenditure, decreased body temperature, decreased brown adipose tissue temperature, and decreased UCP1 expression suggesting an impairment of thermogenesis. In injected mice, hypothalamic gene expression of Sim1, oxytocin (OXT) and thyrotropin releasing hormone (TRH) was reduced by about 50%. These results demonstrate that Sim1 neurons in adult mice regulate both food intake and energy expenditure. Based on the body of work in the field, feeding regulation by Sim1 neurons likely occurs in both the PVH and medial amygdala, in contrast to energy expenditure regulation by Sim1 neurons, which likely is localized to the PVH.