Molecular Characterization of Non-Neurogenic and Neurogenic Lower Urinary Tract Dysfunction (LUTD) in SCI-Induced and Partial Bladder Outlet Obstruction Mouse Models.

We examined bladder function following spinal cord injury (SCI) by repeated urodynamic investigation (UDI), including external urethral sphincter (EUS) electromyography (EMG) in awake restrained mice and correlated micturition parameters to gene expression and morphological changes in the bladder. A partial bladder outlet obstruction (pBOO) model was used for comparison to elucidate both the common and specific features of obstructive and neurogenic lower urinary tract dysfunction (LUTD). Thirty female C57Bl/6J mice in each group received an implanted bladder catheter with additional electrodes placed next to the EUS in the SCI group. UDI assessments were performed weekly for 7 weeks (pBOO group) or 8 weeks (SCI group), after which bladders were harvested for histological and transcriptome analysis. SCI mice developed detrusor sphincter dyssynergia (DSD) one week after injury with high-pressure oscillations and a significantly increased maximal bladder pressure Pmax and were unable to void spontaneously during the whole observation period. They showed an increased bladder-to-bodyweight ratio, bladder fibrosis, and transcriptome changes indicative of extracellular matrix remodeling and alterations of neuronal signaling and muscle contraction. In contrast, pBOO led to a significantly increased Pmax after one week, which normalized at later time points. Increased bladder-to-bodyweight ratio and pronounced gene expression changes involving immune and inflammatory pathways were observed 7 weeks after pBOO. Comparative transcriptome analysis of SCI and pBOO bladders revealed the activation of Wnt and TGF-beta signaling in both the neurogenic and obstructive LUTD and highlighted FGF2 as a major upregulated transcription factor during organ remodeling. We conclude that SCI-induced DSD in mice leads to profound changes in neuronal signaling and muscle contractility, leading to bladder fibrosis. In a similar time frame, significant bladder remodeling following pBOO allowed for functional compensation, preserving normal micturition parameters.

Urinary miRNA profiles discriminate between obstruction-induced bladder dysfunction and healthy controls.

Urgency, frequency and incomplete emptying are the troublesome symptoms often shared between benign prostatic obstruction-induced (BLUTD) and neurogenic (NLUTD) lower urinary tract dysfunction. Previously, using bladder biopsies, we suggested a panel of miRNA biomarkers for different functional phenotypes of the bladder. Urine is a good source of circulating miRNAs, but sex- and age-matched controls are important for urinary metabolite comparison. In two groups of healthy subjects (average age 32 and 57 years old, respectively) the total protein and RNA content was very similar between age groups, but the number of secreted extracellular vesicles (uEVs) and expression of several miRNAs were higher in the young healthy male volunteers. Timing of urine collection was not important for these parameters. We also evaluated the suitability of urinary miRNAs for non-invasive diagnosis of bladder outlet obstruction (BOO). A three urinary miRNA signature (miR-10a-5p, miR-301b-3p and miR-363-3p) could discriminate between controls and patients with LUTD (BLUTD and NLUTD). This panel of representative miRNAs can be further explored to develop a non-invasive diagnostic test for BOO. The age-related discrepancy in the urinary miRNA content observed in this study points to the importance of selecting appropriate, age-matched controls.

Effects of opioids and benzodiazepines on bladder function of awake restrained mice.

OBJECTIVE: We aimed to study the effects of anaesthetics on bladder function using repeated urodynamic investigation (UDI) including external urethral sphincter (EUS) electromyography (EMG) in awake restrained mice. MATERIALS AND METHODS: Female C57Bl/6J mice underwent either bladder catheter (n=6) or bladder catheter plus electrodes (n=10) implantation next to the EUS. A control group (n=3) was included for histological analysis. Following awake UDI, the effects of midazolam (5 mg/kg) and opioids (fentanyl (50 µg/kg) and hydromorphine (250 µg/kg)) on bladder function were studied. Mice were allowed to recover from drug application for at least one day before being subjected to the next drug and UDI. Bladder weight was assessed and fibrotic changes were analysed by Masson's trichrome staining. RESULTS: EUS-EMG activity during voiding was reduced compared to before and after voiding in baseline measurements. Threshold and maximal detrusor pressure were significantly increased in both midazolam and the opioids. The opioids lead to either a significantly increased bladder filling volume and micturition cycle duration (hydromorphine) or a complete loss of the voiding phase leading to overflow incontinence (fentanyl). Bladder-to bodyweight ratio was significantly increased in both groups with an implanted catheter compared to controls. No differences were observed between the groups with- or without implanted electrodes regarding bladder-to bodyweight ratio, bladder fibrosis and urodynamic parameters. CONCLUSIONS: Repeated UDIs combined with EUS-EMG are feasible in the awake mouse model. The presence of electrodes next to the EUS does not obstruct the bladder outlet. Opioids and benzodiazepines severely interfere with physiological bladder function: fentanyl and hydromorphine disrupted the voiding phase evidenced by the reduced coordination of EUS activity with detrusor contraction, while bladder emptying under midazolam was achieved by EUS relaxation only.

Gene expression analysis in the mouse brainstem identifies Cart and Nesfatin as neuropeptides coexpressed in the Calbindin-positive neurons of the Nucleus papilio.

STUDY OBJECTIVES: The brainstem contains several neuronal populations, heterogeneous in terms of neurotransmitter/neuropeptide content, which are important for controlling various aspects of the rapid eye movement (REM) phase of sleep. Among these populations are the Calbindin (Calb)-immunoreactive NPCalb neurons, located in the Nucleus papilio, within the dorsal paragigantocellular nucleus (DPGi), and recently shown to control eye movement during the REM phase of sleep. METHODS: We performed in-depth data mining of the in situ hybridization data collected at the Allen Brain Atlas, in order to identify potentially interesting genes expressed in this brainstem nucleus. Our attention focused on genes encoding neuropeptides, including Cart (Cocaine and Amphetamine Regulated Transcripts) and Nesfatin 1. RESULTS: While nesfatin 1 appeared ubiquitously expressed in this Calb-positive neuronal population, Cart was coexpressed in only a subset of these glutamatergic NPCalb neurons. Furthermore, an REM sleep deprivation and rebound assay performed with mice revealed that the Cart-positive neuronal population within the DPGi was activated during REM sleep (as measured by c-fos immunoreactivity), suggesting a role of this neuropeptide in regulating some aspects of REM sleep. CONCLUSIONS: The assembled information could afford functional clues to investigators, conducive to further experimental pursuits.