Cytokeratin 5 and cytokeratin 20 inversely correlate with tumour grading in Ta non-muscle-invasive bladder cancer.

Cytokeratin 5 is a marker of basal molecular subtypes of muscle-invasive bladder cancer (MIBC), which correlates with worse overall survival compared to luminal subtypes. Our observations have not confirmed CK5 as a marker of high-grade (HG) disease in Ta non-muscle-invasive bladder cancer (NMIBC). Therefore, to understand the basal-luminal immunohistochemistry profile in Ta NMIBC, we performed immunohistochemistry for CK5, P40, P63 (basal), GATA3 and CK20 (luminal) and studied the correlation with HG and clinical outcome in 109 patients with Ta NMIBC. HG and low-grade (LG) diseases were scored in each patient. Four different CK5 patterns were evaluated: absent (median 41.3%), normal (72.5%), rising (84.4%) and full thickness (23.9%). The median percentage of GATA3 was 100%. HG disease and CK5 expression and rising CK5 pattern had a significant inverse correlation, whereas HG disease and CK20 expression had a significant positive correlation. We also found a significant inverse correlation between CK5 expression and CK20 expression. Quantitative PCR confirmed that the presence of CK5 correlated with up-regulation of CK5 RNA. None of the markers could differentiate patients with regard to clinical outcome. Our results suggest a role for CK5 and CK20 in differentiating between LG and HG disease in Ta NMIBC.

Development and External Validation of a Multiparametric Magnetic Resonance Imaging and International Society of Urological Pathology Based Add-On Prediction Tool to Identify Prostate Cancer Candidates for Pelvic Lymph Node Dissection.

PURPOSE: We sought to expand current prediction tools for lymph node invasion in patients with prostate cancer using current state-of-the-art available tumor information, including multiparametric magnetic resonance imaging based tumor stage and detailed biopsy information. MATERIALS AND METHODS: We selected patients with prostate cancer for study who had available registered information on ISUP (International Society of Urological Pathology) based biopsy grading and multiparametric magnetic resonance imaging, and who had undergone radical prostatectomy with extended pelvic lymph node dissection. We developed a lymph node invasion prediction tool in 420 patients and externally validated it in 187. A concordance index was estimated to quantify the discriminative performance of the model. RESULTS: In the development cohort a median of 21 lymph nodes were removed per patient and 71 patients (16.9%) were diagnosed with lymph node invasion. Statistically significant predictors of lymph node invasion were the initial prostate specific antigen value, multiparametric magnetic resonance imaging based T stage, maximum tumor length in 1 core in mm and ISUP grade group corresponding to the maximum tumor involvement in 1 core. The predictive accuracy of this lymph node invasion prediction tool was 79.7% after fivefold internal cross validation and 72.5% after external validation. CONCLUSIONS: We report a contemporary, externally validated prediction tool for lymph node invasion in patients with prostate cancer. This prediction tool is a response to the paradigm shift from systematic to targeted biopsies by incorporating additional core specific biopsy information instead of the percent of positive cores. This new tool will also overcome stage migration, which is a potential risk when multiparametric magnetic resonance imaging information is used in digital rectal examination based nomograms.

The Cancer of the Bladder Risk Assessment (COBRA) score for estimating cancer-specific survival after radical cystectomy: external validation in a large bi-institutional cohort.

OBJECTIVE: To perform an external validation of the Cancer of the Bladder Risk Assessment (COBRA) score for estimating cancer-specific survival (CSS) after radical cystectomy (RC) in a large bi-institutional cohort of patients. PATIENTS AND METHODS: Patients treated with RC and lymph node dissection (LND) between May 1996 and July 2017 were retrieved from the RC databases of Leuven and Turin. Collected variables were age at RC, tumour stage, lymph node (LN) density, neoadjuvant chemotherapy, the extent of LND, and nodal stage. The primary outcome was CSS visualised using Kaplan-Meier plots. Cox proportional hazard models were used to assess the impact of variables on CSS. We performed a pairwise comparison between the COBRA score levels using a log-rank test corrected by Bonferroni, and developed a simplified COBRA score with three risk categories. To compare models, we assessed concordance indices (C-indices), receiver operating characteristic curves with area under the curve (AUC), calibration plots, and decision curve analysis (DCA). Finally, we compared both COBRA and simplified COBRA models with the established American Joint Committee on Cancer (AJCC) model. RESULTS: A total of 812 patients were included. All COBRA score variables had a significant impact on CSS in a Cox proportional hazard model. However, pairwise comparison of the COBRA subscores could not differentiate significantly between all COBRA score levels. Based on these findings, we developed a simplified COBRA score by introducing three categories within the following COBRA score ranges: low- (0-1) vs intermediate- (2-4) vs high-risk (5-7). A pairwise comparison could discriminate significantly between all COBRA risk categories. When finally comparing COBRA and simplified COBRA models with the AJCC model, AJCC performed better than both. C-indices, AUCs, calibration plots and DCA for AJCC were all better compared with the original and simplified COBRA models. CONCLUSION: We performed an external validation of the COBRA score in a large bi-institutional cohort. We observed that several risk groups had overlapping CSS, demonstrating suboptimal performance of the COBRA score. Therefore, we constructed a simplified model with three COBRA score risk categories. This model resulted in demarcated risk groups with non-overlapping CSS and good predictive accuracy. However, both COBRA score models were outperformed by the AJCC staging system. Therefore, we conclude that the AJCC staging system should remain the current standard for stratifying patients after RC for CSS.

Genito-urinary genomics and emerging biomarkers for immunomodulatory cancer treatment.

Immunotherapy is gradually becoming a key factor in the therapeutic algorithm for patients with genito-urinary (GU) cancers at different stages of disease. Robust and reliable biomarkers are crucial for an appropriate inclusion of patients in clinical trials and for a reliable patient selection for treatments with immunomodulatory drugs. The increasing knowledge on the genomic landscape of GU cancers supports stratification of patients for targeted therapies. This review focusses on emerging biomarkers and the role of genomics in predicting clinical benefit to immunomodulatory agents in GU cancers. Based on cancer incidences and available data we restricted this overview to bladder, prostate and renal cancer.

Functional and molecular characterisation of the bilateral pelvic nerve crush injury rat model for neurogenic detrusor underactivity.

OBJECTIVES: To create a rat model for neurogenic detrusor underactivity (DU) by bilateral pelvic nerve crush injury (BPNI) and to study temporal changes in detrusor contractility and morphology. MATERIALS AND METHODS: Male Sprague-Dawley rats were subjected to BPNI or sham surgery and evaluated at 1, 3 and 9 weeks after surgery. Bladder function was determined in vivo by awake cystometry, micturition pattern analysis, and 24-h urine collection. Bladders were harvested for in vitro pharmacological investigation by isometric tension recording. Bladders and major pelvic ganglia were investigated by quantitative reverse transcription-polymerase chain reaction and histochemistry. RESULTS: Overflow incontinence was observed at 1 week after BPNI. At 3 and 9 weeks after BPNI, rats showed a bladder phenotype characteristic for DU with increased post-void residual urine volumes, reduced voiding efficiencies, and lower maximum pressures. In isolated bladder strips, contractile responses to KCl, carbachol, and α,ß-methylene adenosine 5'-triphosphate (α,ß-mATP) were preserved. On the other hand, neural-induced contractility was reduced after BPNI, in line with reduced expression of protein gene product 9.5 and choline acetyltransferase in the major pelvic ganglion at 1 week after BPNI. The bladder-to-body weight ratio and detrusor thickness increased after BPNI, indicating detrusor hypertrophy to compensate for the reduced neural input. CONCLUSIONS: BPNI induces a rat model for neurogenic DU. In this model, the detrusor maintains its contractility but denervation of the detrusor was observed.

Comparative immunohistochemical characterization of interstitial cells in the urinary bladder of human, guinea pig and pig.

Interstitial cells (ICs) are thought to play a functional role in urinary bladder. Animal models are commonly used to elucidate bladder physiology and pathophysiology. However, inter-species comparative studies on ICs are rare. We therefore analyzed ICs and their distribution in the upper lamina propria (ULP), the deeper lamina propria (DLP) and the detrusor muscular layer (DET) of human, guinea pig (GP) and pig. Paraffin slices were examined by immunohistochemistry and 3D confocal immunofluorescence of the mesenchymal intermediate filament vimentin (VIM), alpha-smooth muscle actin (αSMA), platelet-derived growth factor receptor alpha (PDGFRα) and transient receptor potential cation channel A1 (TRPA1). Image stacks were processed for analysis using Huygens software; quantitative analysis was performed with Fiji macros. ICs were identified by immunoreactivity for VIM (excluding blood vessels). In all species ≥ 75% of ULP ICs were VIM+/PDGFRα+ and ≥ 90% were VIM+/TRPA1+. In human and pig ≥ 74% of ULP ICs were VIM+/αSMA+, while in GP the percentage differed significantly with only 37% VIM+/αSMA+ ICs. Additionally, over 90% of αSMA+ ICs were also TRPA1+ and PDGFRα+ in human, GP and pig. In all three species, TRPA1+ and PDGFRα+ ICs point to an active role for these cells in bladder physiology, regarding afferent signaling processes and signal modification. We hypothesize that decline in αSMA-positivity in GP reflects adaptation of bladder histology to smaller bladder size. In our experiments, pig bladder proved to be highly comparable to human urinary bladder and seems to provide safer interpretation of experimental findings than GP.

Neoadjuvant degarelix with or without apalutamide followed by radical prostatectomy for intermediate and high-risk prostate cancer: ARNEO, a randomized, double blind, placebo-controlled trial.

BACKGROUND: Recent retrospective data suggest that neoadjuvant androgen deprivation therapy can improve the prognosis of high-risk prostate cancer (PCa) patients. Novel androgen receptor pathway inhibitors are nowadays available for treatment of metastatic PCa and these compounds are promising for early stage disease. Apalutamide is a pure androgen antagonist with a very high affinity with the androgen receptor. The combination of apalutamide with degarelix, an LHRH antagonist, could increase the efficacy compared to degarelix alone. OBJECTIVE: The primary objective is to assess the difference in proportions of minimal residual disease at prostatectomy specimen between apalutamide + degarelix vs placebo + degarelix. Various secondary endpoints are assessed: variations of different biomarkers at the tumour level (tissue microarrays to evaluate DNA-PKs, PARP, AR and splice variants, PSMA, etc.), whole transcriptome sequencing, exome sequencing and clinical (PSA and testosterone kinetics, early biochemical recurrence free survival, quality of life, safety, etc.) and radiological endpoints. METHODS: ARNEO is a single centre, phase II, randomized, double blind, placebo-controlled trial. The plan is to include at least 42 patients per each of the two study arms. Patients with intermediate/high-risk PCa and who are amenable for radical prostatectomy with pelvic lymph node dissection can be included. After signing an informed consent, every patient will undergo a pelvic 68Ga -PSMA-11 PSMA PET/MR and receive degarelix at standard dosage and start assuming apalutamide/placebo (60 mg 4 tablets/day) for 12 weeks. Within thirty days from the last study medication intake the same imaging will be repeated. Every patient will undergo PSA and testosterone testing the day of randomization, before the first drug intake, and after the last dose. Formalin fixed paraffin embedded tumour samples will be collected and used for transcriptome analysis, exome sequencing and immunohistochemistry. DISCUSSION: ARNEO will allow us to answer, first, whether the combined treatment can result in an increased proportion of patients with minimal residual disease. Secondly, It will enable the study of the molecular consequences at the level of the tumour. Thirdly, what the consequences are of new generation androgen receptor pathway inhibitors on 68Ga -PSMA-11 PET/MR. Finally, various clinical, safety and quality of life data will be collected. TRIAL REGISTRATION: EUDRaCT number: 2016-002854-19 (authorization date 3rd August 2017). clinicalTrial.gov: NCT03080116 .

Galanin Administration Partially Restores Erectile Function After Cavernous Nerve Injury and Mediates Endogenous Nitrergic Nerve Outgrowth In Vitro.

BACKGROUND: Previously, we found that the neuropeptide galanin was strongly upregulated soon after bilateral cavernous nerve injury (BCNI) and that galanin and its receptors were expressed in nitrergic erectile innervation. Galanin has been observed to exert neuroregenerative effects in dorsal root ganglion neurons, but evidence for these effects in the major pelvic ganglion (MPG) after BCNI is lacking. AIM: To evaluate the neurotropic effects of galanin receptor agonists and antagonists in vitro in nitrergic neurons and MPG and in vivo in rats after BCNI. METHODS: Male Sprague-Dawley rats underwent BCNI and sham surgery. Organ culture and single-cell neuron culture of the MPG were performed. Osmotic pump treatment with the galanin agonist in vivo and measurement of erectile response to electrostimulation after BCNI, immunohistochemical localization of galanin and receptors in the human neurovascular bundle, and myographic analysis of rat corpus cavernosum smooth muscle relaxation to galanin receptor agonists were investigated. OUTCOMES: Neurite outgrowth in vitro and erectile response to electrostimulation after BCNI in vivo, immunohistochemical localization of galanin and receptors, and penile muscle relaxation in vitro. RESULTS: Galanin showed neurotrophic action in vitro and inhibition of endogenous galanin significantly impaired neurite outgrowth in nitrergic but not in sympathetic MPG neurons. In vivo administration of a selective galanin receptor-2 agonist, M1145, resulted in partial recovery of erectile function (EF) after BCNI. Galanin did not act as a direct vasodilator on corpus cavernosum muscle strips. CLINICAL TRANSLATION: Endogenous neurotrophins such as galanin could be used as a strategy to improve EF for patients after BCNI from radical prostatectomy. STRENGTHS AND LIMITATIONS: We evaluated the effect of galanin on nerve regeneration and EF recovery in vivo and in vitro. Limitations include the lack of washout period for the in vivo experiment and absence of differences in the expression of neuronal markers between treatment groups. CONCLUSIONS: We identified galanin as a potential endogenous mechanism for nerve regeneration after BCNI, which could play a physiologic role in EF recovery after radical prostatectomy. In vivo treatment with exogenous galanin was beneficial in enhancing EF recovery after BCNI, but further research is necessary to understand the underlying mechanisms. Weyne E, Hannan JL, Gevaert T, et al. Galanin Administration Partially Restores Erectile Function After Cavernous Nerve Injury and Mediates Endogenous Nitrergic Nerve Outgrowth In Vitro. J Sex Med 2018;15:480-491.

3D-electron microscopic characterization of interstitial cells in the human bladder upper lamina propria.

AIMS: To explore the ultrastructure of interstitial cells in the upper lamina propria of the human bladder, to describe the spatial relationships and to investigate cell-cell contacts. METHODS: Focused ion beam scanning electron microscopy (FIB-SEM), 3-View SEM and confocal laser scanning microscopy were used to analyze the 3D ultrastructure of the upper lamina propria in male and female human bladders. RESULTS: 3View-SEM image stacks as large as 59 × 59 × 17 µm3 (xyz) at a resolution of 16 × 16 × 50 nm3 and high resolution (5 × 5 × 10 nm3 ) FIB-SEM stacks could be analyzed. Interstitial cells with myoid differentiation (mIC) and fibroblast like interstitial cells (fIC) were the major cell types in the upper lamina propria. The flat, sheet-like ICs were oriented strictly parallel to the urothelium. No spindle shaped cells were present. We furthermore identified one branched cell (bIC) with several processes contacting urothelial cells by penetrating the basal membrane. This cell did not make any contacts to other ICs within the upper lamina propria. We found no evidence for the occurrence of telocytes in the upper lamina propria. CONCLUSIONS: Comprehensive 3D-ultrastructural analysis of the human bladder confirmed distinct subtypes of interstitial cells. We provide evidence for a foremost unknown direct connection between a branched interstitial cell and urothelial cells of which the functional role has still to be elucidated. 3D-ultrastructure analyses at high resolution are needed to further define the subpopulations of lamina propria cells and cell-cell interactions.

The stem cell growth factor receptor KIT is not expressed on interstitial cells in bladder.

The mast/stem cell growth factor receptor KIT has long been assumed to be a specific marker for interstitial cells of Cajal (ICC) in the bladder, with possible druggable perspectives. However, several authors have challenged the presence of KIT+ ICC in recent years. The aim of this study was therefore to attempt to clarify the conflicting reports on KIT expression in the bladder of human beings, rat, mouse and guinea pig and to elucidate the possible role of antibody-related issues and interspecies differences in this matter. Fresh samples were obtained from human, rat, mouse and guinea pig cystectomies and processed for single/double immunohistochemistry/immunofluorescence. Specific antibodies against KIT, mast cell tryptase (MCT), anoctamin-1 (ANO1) and vimentin were used to characterize the cell types expressing KIT. Gut (jejunum) tissue was used as an external antibody control. Our results revealed KIT expression on mast cells but not on ICC in human, rat, mouse and guinea pig bladder. Parallel immunohistochemistry showed KIT expression on ICC in human, rat, mouse and guinea pig gut, which confirmed the selectivity of the KIT antibody clones. In conclusion, we have shown that KIT+ cells in human, rat, mouse and guinea pig bladder are mast cells and not ICC. The present report is important as it opposes the idea that KIT+ ICC are present in bladder. In this perspective, functional concepts of KIT+ ICC being involved in sensory and/or motor aspects of bladder physiology should be revised.

Comparative study of the organisation and phenotypes of bladder interstitial cells in human, mouse and rat.

With most research on interstitial cells (IC) in the bladder being conducted on animal models, it remains unclear whether all structural and functional data on IC from animal models can be translated to the human context. This prompted us to compare the structural and immunohistochemical properties of IC in bladders from mouse, rat and human. Tissue samples were obtained from the bladder dome and subsequently processed for immunohistochemistry and electron microscopy. The ultrastructural properties of IC were compared by means of electron microscopy and IC were additionally characterized with single/double immunohistochemistry/immunofluorescence. Our results reveal a similar organization of the IC network in the upper lamina propria (ULP), the deep lamina propria (DLP) and the detrusor muscle in human, rat and mouse bladders. Furthermore, despite several similarities in IC phenotypes, we also found several obvious inter-species differences in IC, especially in the ULP. Most remarkably in this respect, ULP IC in human bladder predominantly displayed a myoid phenotype with abundant presence of contractile micro-filaments, while those in rat and mouse bladders showed a fibroblast phenotype. In conclusion, the organization of ULP IC, DLP IC and detrusor IC is comparable in human, rat and mouse bladders, although several obvious inter-species differences in IC phenotypes were found. The present data show that translating research data on IC in laboratory animals to the human setting should be carried out with caution.

Brief Report: The Deletion of the Phosphatase Regulator NIPP1 Causes Progenitor Cell Expansion in the Adult Liver.

The Ppp1r8 gene encodes NIPP1, a nuclear interactor of protein phosphatase PP1. The deletion of NIPP1 is embryonic lethal at the gastrulation stage, which has hampered its functional characterization in adult tissues. Here, we describe the effects of a conditional deletion of NIPP1 in mouse liver epithelial cells. Ppp1r8(-/-) livers developed a ductular reaction, that is, bile-duct hyperplasia with associated fibrosis. The increased proliferation of biliary epithelial cells was at least partially due to an expansion of the progenitor cell compartment that was independent of liver injury. Gene-expression analysis confirmed an upregulation of progenitor cell markers in the liver knockout livers but showed no effect on the expression of liver-injury associated regulators of cholangiocyte differentiation markers. Consistent with an inhibitory effect of NIPP1 on progenitor cell proliferation, Ppp1r8(-/-) livers displayed an increased sensitivity to diet-supplemented 3,5-diethoxycarbonyl-1,4-dihydrocollidine, which also causes bile-duct hyperplasia through progenitor cell expansion. In contrast, the liver knockouts responded normally to injuries (partial hepatectomy, single CCl4 administration) that are restored through proliferation of differentiated parenchymal cells. Our data indicate that NIPP1 does not regulate the proliferation of hepatocytes but is a suppressor of biliary epithelial cell proliferation, including progenitor cells, in the adult liver. Stem Cells 2016;34:2256-2262.

Assessing Tumor-infiltrating Lymphocytes in Solid Tumors: A Practical Review for Pathologists and Proposal for a Standardized Method From the International Immunooncology Biomarkers Working Group: Part 1: Assessing the Host Immune Response, TILs in Invasive Breast Carcinoma and Ductal Carcinoma In Situ, Metastatic Tumor Deposits and Areas for Further Research.

Assessment of tumor-infiltrating lymphocytes (TILs) in histopathologic specimens can provide important prognostic information in diverse solid tumor types, and may also be of value in predicting response to treatments. However, implementation as a routine clinical biomarker has not yet been achieved. As successful use of immune checkpoint inhibitors and other forms of immunotherapy become a clinical reality, the need for widely applicable, accessible, and reliable immunooncology biomarkers is clear. In part 1 of this review we briefly discuss the host immune response to tumors and different approaches to TIL assessment. We propose a standardized methodology to assess TILs in solid tumors on hematoxylin and eosin sections, in both primary and metastatic settings, based on the International Immuno-Oncology Biomarker Working Group guidelines for TIL assessment in invasive breast carcinoma. A review of the literature regarding the value of TIL assessment in different solid tumor types follows in part 2. The method we propose is reproducible, affordable, easily applied, and has demonstrated prognostic and predictive significance in invasive breast carcinoma. This standardized methodology may be used as a reference against which other methods are compared, and should be evaluated for clinical validity and utility. Standardization of TIL assessment will help to improve consistency and reproducibility in this field, enrich both the quality and quantity of comparable evidence, and help to thoroughly evaluate the utility of TILs assessment in this era of immunotherapy.

Assessing Tumor-Infiltrating Lymphocytes in Solid Tumors: A Practical Review for Pathologists and Proposal for a Standardized Method from the International Immuno-Oncology Biomarkers Working Group: Part 2: TILs in Melanoma, Gastrointestinal Tract Carcinomas, Non-Small Cell Lung Carcinoma and Mesothelioma, Endometrial and Ovarian Carcinomas, Squamous Cell Carcinoma of the Head and Neck, Genitourinary Carcinomas, and Primary Brain Tumors.

Assessment of the immune response to tumors is growing in importance as the prognostic implications of this response are increasingly recognized, and as immunotherapies are evaluated and implemented in different tumor types. However, many different approaches can be used to assess and describe the immune response, which limits efforts at implementation as a routine clinical biomarker. In part 1 of this review, we have proposed a standardized methodology to assess tumor-infiltrating lymphocytes (TILs) in solid tumors, based on the International Immuno-Oncology Biomarkers Working Group guidelines for invasive breast carcinoma. In part 2 of this review, we discuss the available evidence for the prognostic and predictive value of TILs in common solid tumors, including carcinomas of the lung, gastrointestinal tract, genitourinary system, gynecologic system, and head and neck, as well as primary brain tumors, mesothelioma and melanoma. The particularities and different emphases in TIL assessment in different tumor types are discussed. The standardized methodology we propose can be adapted to different tumor types and may be used as a standard against which other approaches can be compared. Standardization of TIL assessment will help clinicians, researchers and pathologists to conclusively evaluate the utility of this simple biomarker in the current era of immunotherapy.

Topographies and isoforms of the progesterone receptor in female human, rat and mouse bladder.

Steroid hormones such as progesterone are known to influence bladder function. Progesterone effects are mediated by the progesterone receptor (PR) but no detailed studies of PR in bladder exist. We have investigated the presence, topography and subtypes of PR in mouse, rat and human bladder. Fresh tissue samples were obtained from cystectomies in female humans, rats and mice (n = 7 per group). Tissue samples were processed for immunohistochemistry (IHC), immunofluorescence (IF) and western blot (WB) and, for each species, a panel of specific PR antibody clones was used. Interpretation of IHC/IF was carried out by light/fluorescent microscopy and of WB via standard WB software. IHC/IF in female human bladder showed PR on the interstitial cells in the lamina propria and between detrusor smooth muscle cells, whereas in female rat and mouse bladder, PR was only found on the urothelium. WB in human bladder showed a 78-kD and a 60-kDa band, respectively, corresponding to a modified PR isoform A and PR isoform C. WB in rat and mice bladder showed a 60 kDa band and a 37 kDa band, respectively corresponding with PR isoform C and an unknown isoform. This is the first detailed investigation of the precise location and presence of several isoforms of PR in bladder, together with a comparison of these data between human, rat and mouse. Our study has revealed complex PR families in bladders from the various species studied and demonstrates obvious inter-species differences in PR topography and isoforms.

Identification of different phenotypes of interstitial cells in the upper and deep lamina propria of the human bladder dome.

PURPOSE: There is increasing evidence for an important role of the lamina propria in bladder physiology and interstitial cells seem to have a key role in this area. Interstitial cells in the upper lamina propria have been studied most frequently. We characterized interstitial cells in the deeper lamina propria and hypothesized that the 2 interstitial cell populations have different phenotypes based on their ultrastructural and immunohistochemical properties. MATERIALS AND METHODS: Tissue samples were obtained from macroscopically and microscopically normal areas of radical cystectomy specimens. A panel of immunohistochemical markers was used to characterize lamina propria interstitial cells. Single/double immunohistochemistry/immunofluorescence was performed. At a second phase electron microscopy was used to compare upper and deeper lamina propria interstitial cells. RESULTS: Overall the phenotype of upper lamina propria interstitial cells was vimentin, α-smooth muscle actin, caveolin-1 and 2, PDGFRα, and nonphosphorylated and phosphorylated connexin 43 positive, and CD34 and c-kit negative. The overall phenotype of deeper lamina propria interstitial cells was vimentin, CD34 and nonphosphorylated connexin 43 positive, and α-smooth actin, caveolin-1 and 2, PDGFRα, phosphorylated connexin 43 and c-kit negative. Based on ultrastructural findings upper lamina propria interstitial cells were fibroblasts with myoid features and sparse myofibroblasts while deeper lamina propria interstitial cells were interstitial cell of Cajal-like cells. CONCLUSIONS: To our knowledge this is the first study of 2 main interstitial cell populations in the upper and deeper lamina propria of the human bladder with distinct ultrastructural and immunohistochemical phenotypes. Future research is needed to elucidate whether these morphological findings reflect different roles for upper and deeper lamina propria interstitial cells in bladder physiology.

Characterization of subepithelial interstitial cells in normal and pathological human prostate.

AIMS: To characterize the subepithelial (SE) stromal cells in normal human prostate and to study phenotypical changes in these SE stromal cells in benign prostate hyperplasia (BPH) and prostate cancer (PCa). METHODS AND RESULTS: Tissue was obtained from normal, hyperplastic and tumoral areas in prostatectomy specimens. Tissue samples were processed for morphology, immunohistochemistry, immunofluorescence and electron microscopy. An ultrastructural and immunohistochemical phenotype for the SE stromal cells was assessed, and changes occurring in BPH and PCa were looked for. Based on the ultrastructural findings the dominant SE stromal cell types in normal prostate were interstitial Cajal-like cells and spindle-shaped myoid cells with both myoid and fibroblastic features. An immunohistochemical correlate was found with selective expression of mesenchymal and myoid cell markers. In BPH and PCa, a changed stromal cell composition of the SE region was found. Furthermore, direct contacts between spindle-shaped myoid cells and tumour cells were observed in PCa. CONCLUSIONS: The present study shows for the first time that the SE area in the human prostate houses different stromal cell types with distinct phenotypes. In BPH and PCa specific disease-related changes were observed in the organization and phenotypes of SE interstitial cells.

Administration of imatinib mesylate in rats impairs the neonatal development of intramuscular interstitial cells in bladder and results in altered contractile properties.

AIMS: The KIT receptor is considered as a reliable marker for a subpopulation of interstitial cells (IC), and by persistent neonatal inhibition of KIT we have investigated the role of this receptor in the development of IC-networks in bladder and we have observed the functional consequences of this inhibition. METHODS: Newborn rat pups were treated daily with the KIT inhibitor imatinib mesylate (IM). After 7 days animals were sacrificed and bladder samples were dissected for morphological and functional studies. Morphological research consisted of immunohistochemistry with IC specific antigens (KIT and vimentin) and electron microscopy. The functional studies were based on isolated bladder strips in organ baths, in which spontaneous bladder contractility and the response to a non-subtype selective muscarinic agonist was evaluated. RESULTS: Suburothelial and intramuscular IC were found and characterized in neonatal rat bladder. IM-treatment induced a significant decrease in numbers of IC based on specific immunohistochemical markers, and electron microscopy revealed evidence of IC cell injury. These morphological alterations were observed on intramuscular IC only and not on IC in the suburothelium. Isolated muscle strips from IM-treated animals had a lower contractile frequency and an altered response to muscarinic agonists. CONCLUSIONS: The present study shows the presence of regional subpopulations of IC in neonatal rat bladder, provides evidence for a dependence on KIT of the development of intramuscular IC and supports the hypothesis that a poor development of networks of intramuscular IC might have repercussions on spontaneous and muscarinic-induced bladder contractility.

Inhibition of the cation channel TRPV4 improves bladder function in mice and rats with cyclophosphamide-induced cystitis.

Reduced functional bladder capacity and concomitant increased micturition frequency (pollakisuria) are common lower urinary tract symptoms associated with conditions such as cystitis, prostatic hyperplasia, neurological disease, and overactive bladder syndrome. These symptoms can profoundly affect the quality of life of afflicted individuals, but available pharmacological treatments are often unsatisfactory. Recent work has demonstrated that the cation channel TRPV4 is highly expressed in urothelial cells and plays a role in sensing the normal filling state of the bladder. In this article, we show that the development of cystitis-induced bladder dysfunction is strongly impaired in Trpv4(-/-) mice. Moreover, we describe HC-067047, a previously uncharacterized, potent, and selective TRPV4 antagonist that increases functional bladder capacity and reduces micturition frequency in WT mice and rats with cystitis. HC-067047 did not affect bladder function in Trpv4(-/-) mice, demonstrating that its in vivo effects are on target. These results indicate that TRPV4 antagonists may provide a promising means of treating bladder dysfunction.