MRI and active surveillance: thoughts from across the pond.

In the United States (US), urological guidelines recommend active surveillance (AS) for patients with low-risk prostate cancer (PCa) and endorse it as an option for those with favorable intermediate-risk PCa with a > 10-year life expectancy. Multiparametric magnetic resonance imaging (mpMRI) is being increasingly used in the screening, monitoring, and staging of PCa and involves the combination of T2-weighted, diffusion-weighted, and dynamic contrast-enhanced T1-weighted imaging. The American Urological Association (AUA) guidelines provide recommendations about the use of mpMRI in the confirmatory setting for AS patients but do not discuss the timing of follow-up mpMRI in AS. The National Comprehensive Cancer Network (NCCN) discourages using it more frequently than every 12 months. Finally, guidelines state that mpMRI can be used to augment risk stratification but should not replace periodic surveillance biopsy. In this review, we discuss the current literature regarding the use of mpMRI for patients with AS, with a particular focus on the approach in the US. Although AS shows a benefit to the addition of mpMRI to diagnostic, confirmatory, and follow-up biopsy, there is no strong evidence to suggest that mpMRI can safely replace biopsy for most patients and thus it must be incorporated into a multimodal approach. CLINICAL RELEVANCE STATEMENT: According to the US guidelines, regular follow-ups are important for men with prostate cancer on active surveillance, and prostate MRI is a valuable tool that should be utilized, in combination with PSA kinetics and biopsies, for monitoring prostate cancer. KEY POINTS: According to the US guidelines, the addition of MRI improves the detection of clinically significant prostate cancer. Timing interval imaging of patients on active surveillance remains unclear and has not been specifically addressed. MRI should trigger further work-ups, but not replace periodic follow-up biopsies, in men on active surveillance.

High-dimensional Cytometry (ExCYT) and Mass Spectrometry of Myeloid Infiltrate in Clinically Localized Clear Cell Renal Cell Carcinoma Identifies Novel Potential Myeloid Targets for Immunotherapy.

Renal Cell Carcinoma (RCC) is one of the most commonly diagnosed cancers worldwide with research efforts dramatically improving understanding of the biology of the disease. To investigate the role of the immune system in treatment-naïve clear cell Renal Cell Carcinoma (ccRCC), we interrogated the immune infiltrate in patient-matched ccRCC tumor samples, benign normal adjacent tissue (NAT) and peripheral blood mononuclear cells (PBMCs isolated from whole blood, focusing our attention on the myeloid cell infiltrate. Using flow cytometric, MS, and ExCYT analysis, we discovered unique myeloid populations in PBMCs across patient samples. Furthermore, normal adjacent tissues and ccRCC tissues contained numerous myeloid populations with a unique signature for both tissues. Enrichment of the immune cell (CD45+) fraction and subsequent gene expression analysis revealed a number of myeloid-related genes that were differentially expressed. These data provide evidence, for the first time, of an immunosuppressive and pro-tumorigenic role of myeloid cells in early, clinically localized ccRCC. The identification of a number of immune proteins for therapeutic targeting provides a rationale for investigation into the potential efficacy of earlier intervention with single-agent or combination immunotherapy for ccRCC.

Oncologic outcomes among Black and White men with grade group 4 or 5 (Gleason score 8-10) prostate cancer treated primarily by radical prostatectomy.

BACKGROUND: The aim of this study was to describe pathologic and short-term oncologic outcomes among Black and White men with grade group 4 or 5 prostate cancer managed primarily by radical prostatectomy. METHODS: This was a multi-institutional, observational study (2005-2015) evaluating radical prostatectomy outcomes by self-identified race. Descriptive analysis was performed via nonparametric statistical testing to compare baseline clinicopathologic data. Univariable and multivariable time-to-event analyses were performed to assess biochemical recurrence (BCR), metastasis, cancer-specific mortality (CSM), and overall survival between Black and White men. RESULTS: In total, 1662 men were identified with grade group 4 or 5 prostate cancer initially managed by radical prostatectomy. Black men represented 11.3% of the cohort (n = 188). Black men were younger, demonstrated a longer time from diagnosis to surgery, and were at a lower clinical stage (all P < .05). Black men had lower rates of pT3/4 disease (49.5% vs 63.5%; P < .05) but higher rates of positive surgical margins (31.6% vs 26.5%; P = .14) on pathologic evaluation. There was no difference in BCR, CSM, or overall survival over a median follow-up of 40.7 months. Black men had a lower 5-year cumulative incidence of metastasis-free survival (93.6%; 95% confidence interval [CI], 86.5%-97.0%) in comparison with White men (85.8%; 95% CI, 83.1%-88.0%), which did not persist in an age-adjusted analysis. CONCLUSIONS: Black and White men with high-grade prostate cancer at diagnosis demonstrated similar oncologic outcomes when they were managed by primary radical prostatectomy. Our findings suggest that racial disparities in prostate cancer mortality are not related to differences in the efficacy of extirpative therapy.

Effect of Erythropoietin on Erectile Function after Radical Prostatectomy: The ERECT Randomized Clinical Trial.

PURPOSE: Erectile dysfunction significantly impacts quality of life for men undergoing radical prostatectomy for prostate cancer. Erythropoietin is a promising neurotrophic factor for neurogenic erectile dysfunction based on preclinical and retrospective data. MATERIALS AND METHODS: ERECT (NCT00737893) is a phase 2, double-blinded, randomized, placebo-controlled trial (July 2017-December 2019) evaluating the impact of perioperative erythropoietin on recovery of erectile function and other patient-reported, health-related quality of life outcomes after bilateral nerve-sparing radical prostatectomy (3, 6, 9, and 12 months). Erythropoietin (20,000 units) or saline placebo was injected subcutaneously the day before, day of, and day after surgery for 3 total doses. RESULTS: Of 63 patients assessed for eligibility, 56 patients were randomized. Arms (29 erythropoietin, 27 placebo) were well balanced (89.3% robotic, median age 55.5 years). International Index of Erectile Function-Erectile Function Domain (IIEF-EF) scores increased from median 12.5 at 3 months to 24.5 at 12 months. Median 2-week serum hemoglobin was higher for the erythropoietin arm compared to placebo (14.7 vs 13.6, p=0.02). There was no statistically significant difference in IIEF-EF scores at 6 months comparing erythropoietin to placebo (p=0.50) or at other time points (mixed model regression coefficient: -1.7, 95% CI -6.1-2.7, p=0.45). Excellent nerve-sparing rating (10/10) was associated with improved IIEF-EF recovery (+5.2, p=0.022). Other patient-reported, health-related quality of life domains as well as oncologic outcome and complications were similar between arms during followup. CONCLUSIONS: In the context of brief perioperative dosing, erythropoietin did not improve recovery of erectile function for men undergoing radical prostatectomy for prostate cancer compared to placebo. Further research to identify effective adjuncts to improve health-related quality of life for these men is needed.

Testicular ultrasound underestimates the size of small testicular masses: a radiologic-pathologic correlation study.

PURPOSE: Increasing use and resolution of testicular ultrasound imaging has resulted in a greater diagnosis of non-palpable small testicular masses and subsequent over-treatment with orchiectomy. Our aim was to determine the diagnostic accuracy of testicular ultrasound to accurately determine the pathologic size of small testicular masses (SMTMs) and to evaluate the association of various measurements with benign pathology. METHODS: Retrospectively, an institutional testicular cancer database was reviewed to evaluate the patients who underwent an orchiectomy for a testicular mass seen on ultrasound from 2003 to 2017. Three-dimensional measurements were compared from the ultrasound and pathology specimens, including other measures such as tumor volume and percentage of testicular volume. Finally, the predictive accuracy of maximum diameter and tumor volume to predict benign pathology was evaluated using receiver-operating curve analysis. RESULTS: We identified 208 patients and showed that ultrasound significantly underestimated sub-centimeter testicular masses (mean difference 0.56 cm, 95%CI 0.89-0.14, p = 0.004) and testicular masses between 1 and < 2 cm (mean difference 0.50 cm, 95%CI 0.97-0.15, p = 0.009). Tumor volume measured on ultrasound was consistently similar to pathologic tumor volume across all sizes and was significantly correlated (Spearman's Rho = 0.81). Mass volume had a greater predictive accuracy for benign pathology than maximum diameter using a 1 cm cut-off (AUC 0.65 vs 0.60). CONCLUSION: Using the maximal diameter, testicular ultrasound significantly miscalculated the pathologic dimensions of masses less than 2 cm compared to orchiectomy specimens. Volumetric measurements may better represent actual tumor sizes for SMTMs and may be a more useful measure for identifying those a higher risk for benign pathology, however, further studies are required.

Prostate Health Index and multiparametric magnetic resonance imaging to predict prostate cancer grade reclassification in active surveillance.

OBJECTIVE: To identify the value of combining the Prostate Health Index (PHI) and multiparametric magnetic resonance imaging (mpMRI), tools which have previously been shown to be independently predictive of prostate cancer (PCa) grade reclassification (GR; Gleason score >6), for the purpose of predicting GR at the next surveillance biopsy to reduce unnecessary prostate biopsies for men in PCa active surveillance (AS). PATIENTS AND METHODS: Between 2014 and 2019, we retrospectively identified 253 consecutive men in the Johns Hopkins AS programme who had mpMRI and PHI followed by a systematic ± targeted biopsy. PHI and PHI density (PHID) were evaluated across Prostate Imaging-Reporting and Data System version 2.0 (PI-RADSv2) scores and compared to those with and without GR. Next, the negative predictive value (NPV) and area under the receiver operating curve (AUC) were calculated to compare the diagnostic value of PI-RADSv2 score combined with PHI, PHID, or prostate-specific antigen density (PSAD) for GR using their respective first quartile as a cut-off. RESULTS: Of the 253 men, 38 men (15%) had GR. Men with GR had higher PHI values (40.7 vs 32.0, P = 0.001), PHID (0.83 vs 0.57, P = 0.007), and PSAD (0.12 vs 0.10, P = 0.037). A PI-RADSv2 ≤3 alone had a NPV of 91.6% for GR (AUC 0.67). Using a PHI cut-off of 25.6 in addition to PI-RADSv2 ≤3, the NPV and AUC were both increased to 98% and 0.70, respectively. Using a PSAD cut-off of 0.07 ng/mL/mL with PI-RADSv2 had an AUC of 0.69 and NPV of 95.4%. PHI and PI-RADSv2 together could have avoided 20% of biopsies at the cost of missing 2.6% of GRs. CONCLUSIONS: The combination of PHI and mpMRI can aid in the prediction of GR in men on AS and may be useful for decreasing the burden of surveillance prostate biopsies.

Transperineal prostate biopsy with cognitive magnetic resonance imaging/biplanar ultrasound fusion: description of technique and early results.

OBJECTIVE: To describe our technique and early results performing transperineal prostate biopsy using cognitive magnetic resonance imaging (MRI)/biplanar ultrasound fusion. Key components of this technique include use of the PrecisionPoint Transperineal Access System (Perineologic, Cumberland, MD) and simultaneous transrectal ultrasound guidance in the axial and sagittal planes. PATIENTS AND METHODS: In total, 95 patients (38 studied retrospectively and 57 studied prospectively) underwent a transperineal MRI-targeted prostate biopsy using the technique detailed in this manuscript. All biopsies were performed by a single urologist (MAG). Data were collected with respect to cancer detection rates, tolerability, and complications. The subset of patients who were studied prospectively was assessed for complications by telephone interviews performed at 4-6 days and 25-31 days following the prostate biopsy. RESULTS: Between February 2018 and June 2019, 95 men underwent a transperineal prostate biopsy using MRI/biplanar ultrasound fusion guidance. Patients had a total of 124 PI-RADS 3-5 lesions that were targeted for biopsy. In total, 108 (87.1%) lesions were found to harbor prostate cancer of any grade. Grade group ≥ 2 prostate cancer was found in 81 (65.3%) of targeted lesions. The detection rates for grade group ≥ 1 and grade group ≥ 2 prostate cancer rose with increasing PI-RADS score. In 65 (68.4%) cases, the patient's highest grade prostate cancer was found within an MRI target. Additionally, 12 of 55 (21.8%) patients who were found to have no or grade group 1 prostate cancer on systematic biopsy were upgraded to grade group ≥ 2 prostate cancer with MRI targeting. Only 1 (1.1%) patient received periprocedural antibiotics and no patient experienced an infectious complication. Self-limited hematuria and hematospermia were commonly reported following the procedure (75.4% and 40.4%, respectively) and only 1 (1.1%) patient developed urinary retention. CONCLUSIONS: We demonstrate the safety and feasibility of performing transperineal prostate biopsy using cognitive MRI/biplanar ultrasound fusion guidance. The described technique affords the safety benefits of the transperineal approach as well as obviates the need for a formal fusion platform. Additionally, this method can conveniently be performed under local anesthesia with acceptable tolerability.

Outcomes of very high-risk prostate cancer after radical prostatectomy: Validation study from 3 centers.

BACKGROUND: Among men with localized high-risk prostate cancer (PCa), patients who meet very high-risk (VHR) criteria have been shown to experience worse outcomes after radical prostatectomy (RP) in a previous study. Variations of VHR criteria have been suggested to be prognostic in other single-center cohorts, but multicenter outcomes validating VHR criteria have not been described. This study was designed to validate VHR criteria for identifying which PCa patients are at greatest risk for cancer progression. METHODS: Patients with high-risk PCa undergoing RP (2005-2015) at 3 tertiary centers were pooled. The outcomes of men with VHR PCa were compared with the outcomes of those who did not meet VHR criteria. The high-risk criteria were a clinical stage of T3 to T4, a prostate-specific antigen level > 20 ng/mL, or a biopsy Gleason grade sum of 8 to 10. The VHR criteria were multiple high-risk features, >4 biopsy cores with a Gleason grade sum of 8 to 10, or primary Gleason grade pattern 5. Biochemical recurrence, metastasis (METS), and cancer-specific mortality (CSM) were assessed with competing risks regressions. Overall mortality was assessed with Cox survival models. RESULTS: Among 1981 patients with high-risk PCa, men with VHR PCa (n = 602) had adverse pathologic outcomes: 37% versus 25% for positive margins and 37% versus 15% for positive lymph nodes (P < .001 for both comparisons). Patients with VHR PCa also had higher adjusted hazard ratios for METS (2.78; 95% confidence interval [CI], 2.08-3.72), CSM (6.77; 95% CI, 2.91-15.7), and overall mortality (2.44; 95% CI, 1.56-3.80; P < .001 for all comparisons). CONCLUSIONS: In a validation study of patients who underwent treatment for high-risk PCa, VHR criteria were strongly associated with adverse pathologic and oncologic outcomes.

Adjuvant radiation with androgen-deprivation therapy for men with lymph node metastases after radical prostatectomy: identifying men who benefit.

OBJECTIVES: To perform a comparative analysis of three current management strategies for patients with lymph node metastases (LNM; pN1) following radical prostatectomy (RP): observation, androgen-deprivation therapy (ADT), and external beam radiation therapy (EBRT) + ADT. PATIENTS AND METHODS: Patients with LNM after RP were identified using the National Cancer Database (2004-2013). Exclusion criteria included any use of radiation therapy or ADT before RP, clinical M1 disease, or incomplete follow-up data. Patients were categorised according to postoperative management strategy. The primary outcome was overall survival (OS). Kaplan-Meier curves and adjusted multivariable Cox proportional hazards models were employed. Sub-analyses further evaluated patient risk stratification and time to receipt of adjuvant therapy. RESULTS: A total of 8 074 patients met the inclusion criteria. Postoperatively, 4 489 (55.6%) received observation, 2 065 (25.6%) ADT, and 1 520 (18.8%) ADT + EBRT. The mean (median; interquartile range) follow-up was 52.3 (48.0; 28.5-73.5) months. Patients receiving ADT or ADT + EBRT had higher pathological Gleason scores, T-stage, positive surgical margin rates, and nodal burden. Adjusted multivariable Cox models showed improved OS for ADT + EBRT vs observation (hazard ratio [HR] 0.77, 95% confidence interval [CI] 0.64-0.94; P = 0.008) and vs ADT (HR 0.76, 95% CI: 0.63-0.93; P = 0.007). There was no difference in OS for ADT vs observation (HR 1.01, 95% CI: 0.87-1.18; P = 0.88). Findings were similar when restricting adjuvant cohorts for timing of adjuvant therapy. There was no difference in OS between groups for up to 2 549 (31.6%) patients lacking any of the following adverse features: ≥pT3b disease, Gleason score ≥9, three or more positive nodes, or positive surgical margin. CONCLUSIONS: For patients with LNM after RP, the use of adjuvant ADT + EBRT improved OS in the majority of patients, especially those with adverse pathological features. Conversely, adjuvant therapy did not confer significant OS benefit in up to 30% of patients without high-risk features, who may be managed with observation and forego the morbidity associated with immediate ADT or radiation.

Comparison of Pathological Stage in Patients Treated with and without Neoadjuvant Chemotherapy for High Risk Upper Tract Urothelial Carcinoma.

PURPOSE: High risk upper tract urothelial carcinoma has been associated with poor survival outcomes. Limited retrospective data support neoadjuvant chemotherapy prior to radical nephroureterectomy. To validate prior findings we evaluated differences in the pathological stage distribution in patients with high risk upper tract urothelial carcinoma based on the administration of neoadjuvant chemotherapy before radical nephroureterectomy. MATERIALS AND METHODS: We retrospectively analyzed the records of 240 patients with upper tract urothelial carcinoma at The Johns Hopkins Hospital from 2003 to 2017. Patients with biopsy proven high grade disease and a visible lesion on cross-sectional imaging were offered neoadjuvant chemotherapy prior to radical nephroureterectomy. A control group of a time matched cohort of patients with biopsy proven high grade disease underwent extirpative surgery alone. The chi-square and Fisher exact tests were used to evaluate clinical and pathological variables between the cohorts. RESULTS: There were 32 patients in the study group and 208 in the control group. Significantly lower pathological stage was noted in the study group than in the control group (p <0.001). Significantly fewer patients with pT2 disease or higher were treated with neoadjuvant chemotherapy (37.5% vs 59.6%, p = 0.02). There was a 46.5% reduction in the prevalence of pT3 disease or higher in study group patients without clinically node positive or low volume metastatic disease (25.9% vs 48.4%, p = 0.04). A 9.4% complete remission rate was observed in patients who underwent neoadjuvant chemotherapy. CONCLUSIONS: Patients with high risk upper tract urothelial carcinoma treated with neoadjuvant chemotherapy were noted to have a lower pathological stage distribution than patients treated with radical nephroureterectomy alone.

Growth Kinetics of Small Renal Masses on Active Surveillance: Variability and Results from the DISSRM Registry.

PURPOSE: Active surveillance is emerging as a safe and effective strategy for the management of small renal masses (4 cm or less). We characterized the growth rate and its pertinence to clinical outcomes in a prospective multi-institutional study of patients with small renal masses. MATERIALS AND METHODS: Since 2009, the DISSRM (Delayed Intervention and Surveillance for Small Renal Masses) prospective, multi-institutional registry of patients with small renal masses has enrolled patients who elect primary intervention or active surveillance. Patients who elect active surveillance received regularly scheduled imaging and those with 3 or more followup images were included in the current study to evaluate growth rates. RESULTS: We evaluated 318 patients who elected active surveillance, of whom 271 (85.2%) had 3 or more followup images available with a median imaging followup of 1.83 years. The overall mean ± SD small renal mass growth rate was 0.09 ± 1.51 cm per year (median 0.09) with no variables demonstrating statistically significant associations. The growth rate and variability decreased with longer followup (0.54 and 0.07 cm per year at less than 6 months and greater than 1 year, respectively). No patients had metastatic disease or died of kidney cancer. No statistically significant difference was noted in the growth rate in patients with biopsy demonstrated renal cell carcinoma or in those who died. CONCLUSIONS: Small renal mass growth kinetics are highly variable early on active surveillance with growth rates and variability decreasing with time. Early in active surveillance, especially during the initial 6 to 12 months, the growth rate is variable and does not reliably predict death or adverse pathological features in the patient subset with available pathology findings. An elevated growth rate may indicate the need for further assessment with imaging or consideration of biopsy prior to progressing to treatment. Additional followup will inform the best clinical pathway for elevated growth rates.

Retroperitoneal lymph node dissection for testicular seminomas: population-based practice and survival outcomes.

PURPOSE: While retroperitoneal lymph node dissection (RPLND) is traditionally reserved for nonseminomatous germ cell tumors, recent efforts to reduce long-term toxicities of radiation and chemotherapy have turned attention to its application for testicular seminomas. Currently, RPLND is reserved for the post-chemotherapy for stage II testicular seminomas; we aimed to describe current utilization of RPNLD for testicular seminomas by stage and implications for survival. METHODS: A national sample of men diagnosed with stage IA/IB/IS/IIA/IIB/IIC testicular seminoma (1988-2013) was evaluated from SEER Program registries. Stage-specific utilization of RPLND was determined. Cox proportional hazards models, adjusted for age, race, and radiotherapy, evaluated overall (OS) and cancer-specific survival (CSS) for the RPLND cohort. Adjusted models assessed predictors of RPLND. RESULTS: A total of 17,681 men (mean age 38.1 years) with testicular seminoma were included with low utilization of RPLND for stage I disease (1.3% overall) and higher rates for stage II disease (10.6% overall). There were no appreciable trends over time. Patients receiving RPLND did not appear to have worse OS or CSS on adjusted stage-by-stage analysis. Higher stage disease (IIA-IIC) was associated with greater need for RPLND while radiotherapy was associated with decreased use [OR 0.40 (0.32-0.51), p < 0.001]. CONCLUSIONS: Utilization of RPLND for testicular seminomas in the post-chemotherapy setting has remained stable over a 25-year period. Patients undergoing RPLND are a higher risk cohort but stage-by-stage survival outcomes appeared comparable to men not undergoing RPLND. Upcoming trials implementing RPLND as a first-line modality for testicular seminoma or isolated retroperitoneal relapse will help better quantify relative recurrence and survival.

Pathological analysis of the prostatic anterior fat pad at radical prostatectomy: insights from a prospective series.

OBJECTIVE: To assess factors associated with lymphatic drainage and lymph node (LN) metastasis to the prostatic anterior fat pad (PAFP) in men with prostate cancer and the utility of routine PAFP analysis at the time of radical prostatectomy (RP). PATIENTS AND METHODS: Our institution began to prospectively collect PAFP tissue in 2010. The PAFP was removed at the time of RP and sent as a pathological specimen separate from the pelvic LNs and prostate. Consecutive RPs performed at our institution in which the PAFP was removed were reviewed to determine the rate of LNs in the PAFP, the rate of metastatic LNs in the PAFP, and the association of metastatic PAFP LN with clinical and pathological features. The impact on biochemical recurrence (BCR) was assessed with a Cox's proportional hazard model. RESULTS: In all, 2 413 PAFP specimens were available for analysis. LNs were found in the PAFP in 255 (10.6%) cases and metastatic LNs in the PAFPs were found in 14 (0.6%) cases. Metastatic PAFP LNs were associated with anterior tumours in 11 of the 14 cases (P = 0.01), and were present only in preoperative D'Amico intermediate- (six of 14) and high- (eight of 14) risk patients (P < 0.001). Metastatic PAFP LNs were associated with extraprostatic disease in 13 of the 14 cases, although concomitant pelvic LN involvement was present in only four of the 14 cases. With a mean follow-up of 1.5 years, three of the 14 patients with metastatic PAFP LN developed BCR. Positive LN involvement in either the pelvic LN or PAFP had worse BCR than LN-negative patients (P < 0.001); however, there was no difference in BCR between patients with positive pelvic LN and positive PAFP LN (P = 0.5). CONCLUSION: Metastatic PAFP LNs are rare and always occur in the presence of other adverse pathological features. The routine pathological analysis of PAFP as a separate specimen, especially in low-risk disease, may not be warranted.

Role of spinal metabotropic glutamate receptor 5 in pudendal inhibition of the nociceptive bladder reflex in cats.

This study examined the role of spinal metabotropic glutamate receptor 5 (mGluR5) in the nociceptive C-fiber afferent-mediated spinal bladder reflex and in the inhibtion of this reflex by pudendal nerve stimulation (PNS). In α-chloralose-anesthetized cats after spinal cord transection at the T9/T10 level, intravesical infusion of 0.25% acetic acid irritated the bladder, activated nociceptive C-fiber afferents, and induced spinal reflex bladder contractions of low amplitude (<50 cmH2O) and short duration (<20 s) at a smaller bladder capacity ∼80% of saline control capacity. PNS significantly (P < 0.01) increased bladder capacity from 85.5 ± 10.1 to 137.3 ± 14.1 or 148.2 ± 11.2% at 2T or 4T stimulation, respectively, where T is the threshold intensity for PNS to induce anal twitch. MTEP {3-[(2-methyl-4-thiazolyl)ethynyl]pyridine; 3 mg/kg iv, a selective mGluR5 antagonist} completely removed the PNS inhibition and significantly (P < 0.05) increased bladder capacity from 71.8 ± 9.9 to 94.0 ± 13.9% of saline control, but it did not change the bladder contraction amplitude. After propranolol (3 mg/kg iv, a ß1/ß2-adrenergic receptor antagonist) treatment, PNS inhibition remained but MTEP significantly (P < 0.05) reduced the bladder contraction amplitude from 18.6 ± 2.1 to 6.6 ± 1.2 cmH2O and eliminated PNS inhibition. At the end of experiments, hexamethonium (10 mg/kg iv, a ganglionic blocker) significantly (P < 0.05) reduced the bladder contraction amplitude from 20.9 ± 3.2 to 8.1 ± 1.5 cmH2O on average demonstrating that spinal reflexes were responsible for a major component of the contractions. This study shows that spinal mGluR5 plays an important role in the nociceptive C-fiber afferent-mediated spinal bladder reflex and in pudendal inhibition of this spinal reflex.

Propranolol, but not naloxone, enhances spinal reflex bladder activity and reduces pudendal inhibition in cats.

This study examined the role of ß-adrenergic and opioid receptors in spinal reflex bladder activity and in the inhibition induced by pudendal nerve stimulation (PNS) or tibial nerve stimulation (TNS). Spinal reflex bladder contractions were induced by intravesical infusion of 0.25% acetic acid in α-chloralose-anesthetized cats after an acute spinal cord transection (SCT) at the thoracic T9/T10 level. PNS or TNS at 5 Hz was applied to inhibit these spinal reflex contractions at 2 and 4 times the threshold intensity (T) for inducing anal or toe twitch, respectively. During a cystrometrogram (CMG), PNS at 2T and 4T significantly (P < 0.05) increased bladder capacity from 58.0 ± 4.7% to 85.8 ± 10.3% and 96.5 ± 10.7%, respectively, of saline control capacity, while TNS failed to inhibit spinal reflex bladder contractions. After administering propranolol (3 mg/kg iv, a ß1/ß2-adrenergic receptor antagonist), the effects of 2T and 4T PNS on bladder capacity were significantly (P < 0.05) reduced to 64.5 ± 9.5% and 64.7 ± 7.3%, respectively, of the saline control capacity. However, the residual PNS inhibition (about 10% increase in capacity) was still statistically significant (P < 0.05). Propranolol treatment also significantly (P = 0.0019) increased the amplitude of bladder contractions but did not change the control bladder capacity. Naloxone (1 mg/kg iv, an opioid receptor antagonist) had no effect on either spinal reflex bladder contractions or PNS inhibition. At the end of experiments, hexamethonium (10 mg/kg iv, a ganglionic blocker) significantly (P < 0.05) reduced the amplitude of the reflex bladder contractions. This study indicates an important role of ß1/ß2-adrenergic receptors in pudendal inhibition and spinal reflex bladder activity.

Role of spinal GABAA receptors in pudendal inhibition of nociceptive and nonnociceptive bladder reflexes in cats.

Picrotoxin, an antagonist for γ-aminobutyric acid receptor subtype A (GABAA), was used to investigate the role of GABAA receptors in nociceptive and nonnociceptive reflex bladder activities and pudendal inhibition of these activities in cats under α-chloralose anesthesia. Acetic acid (AA; 0.25%) was used to irritate the bladder and induce nociceptive bladder overactivity, while saline was used to distend the bladder and induce nonnociceptive bladder activity. To modulate the bladder reflex, pudendal nerve stimulation (PNS) was applied at multiple threshold (T) intensities for inducing anal sphincter twitching. AA irritation significantly (P < 0.01) reduced bladder capacity to 34.3 ± 7.1% of the saline control capacity, while PNS at 2T and 4T significantly (P < 0.01) increased AA bladder capacity to 84.0 ± 7.8 and 93.2 ± 15.0%, respectively, of the saline control. Picrotoxin (0.4 mg it) did not change AA bladder capacity but completely removed PNS inhibition of AA-induced bladder overactivity. Picrotoxin (iv) only increased AA bladder capacity at a high dose (0.3 mg/kg) but significantly (P < 0.05) reduced 2T PNS inhibition at low doses (0.01-0.1 mg/kg). During saline cystometry, PNS significantly (P < 0.01) increased bladder capacity to 147.0 ± 7.6% at 2T and 172.7 ± 8.9% at 4T of control capacity, and picrotoxin (0.4 mg it or 0.03-0.3 mg/kg iv) also significantly (P < 0.05) increased bladder capacity. However, picrotoxin treatment did not alter PNS inhibition during saline infusion. These results indicate that spinal GABAA receptors have different roles in controlling nociceptive and nonnociceptive reflex bladder activities and in PNS inhibition of these activities.

Somatic modulation of spinal reflex bladder activity mediated by nociceptive bladder afferent nerve fibers in cats.

The goal of the present study was to determine if supraspinal pathways are necessary for inhibition of bladder reflex activity induced by activation of somatic afferents in the pudendal or tibial nerve. Cats anesthetized with α-chloralose were studied after acute spinal cord transection at the thoracic T9/T10 level. Dilute (0.25%) acetic acid was used to irritate the bladder, activate nociceptive afferent C-fibers, and trigger spinal reflex bladder contractions (amplitude: 19.3 ± 2.9 cmH2O). Hexamethonium (a ganglionic blocker, intravenously) significantly (P < 0.01) reduced the amplitude of the reflex bladder contractions to 8.5 ± 1.9 cmH2O. Injection of lidocaine (2%, 1-2 ml) into the sacral spinal cord or transection of the sacral spinal roots and spinal cord further reduced the contraction amplitude to 4.2 ± 1.3 cmH2O. Pudendal nerve stimulation (PNS) at frequencies of 0.5-5 Hz and 40 Hz but not at 10-20 Hz inhibited reflex bladder contractions, whereas tibial nerve stimulation (TNS) failed to inhibit bladder contractions at all tested frequencies (0.5-40 Hz). These results indicate that PNS inhibition of nociceptive afferent C-fiber-mediated spinal reflex bladder contractions can occur at the spinal level in the absence of supraspinal pathways, but TNS inhibition requires supraspinal pathways. In addition, this study shows, for the first time, that after acute spinal cord transection reflex bladder contractions can be triggered by activating nociceptive bladder afferent C-fibers using acetic acid irritation. Understanding the sites of action for PNS or TNS inhibition is important for the clinical application of pudendal or tibial neuromodulation to treat bladder dysfunctions.

Effects of duloxetine and WAY100635 on pudendal inhibition of bladder overactivity in cats.

This study was aimed at determining the effect of duloxetine (a serotonin-norepinephrine reuptake inhibitor) on pudendal inhibition of bladder overactivity. Cystometrograms were performed on 15 cats under α-chloralose anesthesia by infusing saline and then 0.25% acetic acid (AA) to induce bladder overactivity. To inhibit bladder overactivity, pudendal nerve stimulation (PNS) at 5 Hz was applied to the right pudendal nerve at two and four times the threshold (T) intensity for inducing anal twitch. Duloxetine (0.03-3 mg/kg) was administered intravenously to determine the effect on PNS inhibition. AA irritation significantly (P < 0.01) reduced bladder capacity to 27.9 ± 4.6% of saline control capacity. PNS alone at both 2T and 4T significantly (P < 0.01) inhibited bladder overactivity and increased bladder capacity to 83.6 ± 7.6% and 87.5 ± 7.7% of saline control, respectively. Duloxetine at low doses (0.03-0.3 mg/kg) caused a significant reduction in PNS inhibition without changing bladder capacity. However, at high doses (1-3 mg/kg) duloxetine significantly increased bladder capacity but still failed to enhance PNS inhibition. WAY100635 (N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridyl)cyclohexanecarboxamide; a 5-HT1A receptor antagonist, 0.5-1 mg/kg i.v.) reversed the suppressive effect of duloxetine on PNS inhibition and significantly (P < 0.05) increased the inhibitory effect of duloxetine on bladder overactivity but did not enhance the effect of PNS. These results indicate that activation of 5-HT1A autoreceptors on the serotonergic neurons in the raphe nucleus may suppress duloxetine and PNS inhibition, suggesting that the coadministration of a 5-HT1A antagonist drug might be useful in enhancing the efficacy of duloxetine alone and/or the additive effect of PNS-duloxetine combination for the treatment of overactive bladder symptoms.

Tamsulosin and spontaneous passage of ureteral stones in children: a multi-institutional cohort study.

PURPOSE: Tamsulosin is associated with increased passage of ureteral stones in adults but its effectiveness in children is uncertain. We determined the association between tamsulosin and the spontaneous passage of ureteral stones in children. MATERIALS AND METHODS: We performed a multi-institutional retrospective cohort study of patients 18 years or younger who presented between 2007 and 2012 with ureteral stones up to 10 mm and who were treated with tamsulosin or oral analgesics alone. The outcome was spontaneous stone passage, defined as radiographic clearance and/or patient report of passage. Subjects prescribed tamsulosin were matched with subjects prescribed analgesics alone, using nearest neighbor propensity score matching to adjust for treatment selection. Conditional logistic regression models were used to estimate the association between tamsulosin and spontaneous passage of ureteral stones, adjusting for stone size and location. RESULTS: Of 449 children with ureteral stones 334 were eligible for inclusion, and complete data were available for 274 patients from 4 institutions (99 receiving tamsulosin, 175 receiving analgesics alone). Following case matching, there were no differences in age, gender, weight, height, stone size or stone location between the 99 subjects prescribed tamsulosin and the 99 propensity score matched subjects prescribed analgesics alone. In the tamsulosin cohort 55% of ureteral stones passed, compared to 44% in the analgesics alone cohort (p=0.03). In multivariate analysis adjusting for stone size and location tamsulosin was associated with spontaneous passage of ureteral stones (OR 3.31, 95% CI 1.49-7.34). CONCLUSIONS: The odds of spontaneous passage of ureteral stones were greater in children prescribed tamsulosin vs analgesics alone.