Reflex voiding in rat occurs at consistent bladder volume regardless of pressure or infusion rate.

AIMS: The central nervous system (CNS) regulates lower urinary tract reflexes using information from sensory afferents; however, the mechanisms of this process are not well known. Pressure and volume were measured at the onset of the guarding and micturition reflexes across a range of infusion rates to provide insight into what the CNS is gauging to activate reflexes. METHODS: Female Sprague Dawley rats were anesthetized with urethane for open outlet cystometry. A set of 10 infusion rates (ranging 0.92-65.5 mL/h) were pseudo-randomly distributed across 30 single-fill cystometrograms. Bladder pressure and external urethral sphincter electromyography were used for the determination of the onset of the micturition and guarding reflexes, respectively. The bladder volume at the onset of both reflexes was estimated from the total infusion rate during a single fill. RESULTS: In response to many single-fill cystometrograms, there was an increased volume the bladder could store without a significant increase in pressure. Volume was adjusted for this effect for the analysis of how pressure and volume varied with infusion rate at the onset of the micturition and guarding reflexes. In 25 rats, the micturition reflex was evoked at similar volumes across all infusion rates, whereas the pressure at micturition reflex onset increased with increasing infusion rates. In 11 rats, the guarding reflex was evoked at similar pressures across infusion rates, but the volume decreased with increasing infusion rates. CONCLUSIONS: These results suggest that the CNS is interpreting volume from the bladder to activate the micturition reflex and pressure from the bladder to activate the guarding reflex.

Analysis of urethral blood flow by high-resolution laser speckle contrast imaging in a rat model of vaginal distension.

OBJECTIVE: To investigate the feasibility of laser speckle contrast imaging (LSCI) for monitoring urethral blood flow (UBF). MATERIALS AND METHODS: In this study, 18 healthy, virgin female Sprague-Dawley rats aged 8-week-old were used. The animals were divided into the sham group (n = 9) and the vaginal distension (VD) group (n = 9). The sham group underwent one catheterization of the vagina without distension and the VD group underwent one VD. Following the VD or sham treatment for one week, LSCI assessment of urethral blood flow was performed during bladder filling and leak point pressure (LPP) process. RESULTS: During the LPP process, in the VD group, the mean LPP was significantly lower than in the sham group (p < 0.05) and the mean UBF level was also significantly lower than in the sham group (p < 0.05) in the LPP condition. The mean relative change of UBF (Δ Flow) was significantly different between the sham group and VD group. The value was 0.646 ± 0.229 and 0.295 ± 0.19, respectively (p < 0.05). During the bladder filling process, the VD group had a significant lower mean UBF level than the sham group under full bladder conditions (p = 0.008). The mean ΔFlow was also significantly lower than in the sham group. The value was 0.115 ± 0.121 and 0.375 ± 0.127, respectively (p = 0.016). CONCLUSIONS: The results confirmed that LSCI was able to determine UBF in female rats. The VD group had lower baseline UBF and lower increases in UBF during bladder filling and LPP process compared with the sham group.

A Modified Small Intestinal Submucosa Patch with Multifunction to Promote Scarless Repair and Reinvigoration of Urethra.

To reconstruct and restore the functions of the male urethra is a challenging task for urologists. The acellular matrix graft currently used in the clinics is mono-functional and may cause a series of complications including stricture, fibrosis, and stone formation. As a result, such graft materials cannot meet the increasing demand for multifunctionality in the field of urethral tissue engineering. In this context, a multifunctional urethral patch is designed for the repair of urethral defects by mixing protocatechualdehyde (PCA) with small intestinal submucosa (SIS) under an alkalin condition to allow cross linking. As shown, the PCA/SIS patch possesses excellent biocompatibility, antioxidant activity, and anti-inflammatory property. More importantly, this patch can remarkably promote the adhesion, proliferation, and directional extension of rabbit bladder epithelial mucous cells (R-EMCs) as well as rabbit bladder smooth muscle cells (R-SMCs), and upregulate the expression of cytokeratin in the EMCs and contractile protein in the SMCs in vitro. In vivo experiments also confirm that the PCA/SIS patch can significantly enhance scarless repair of urethral defects in rabbits by facilitating smooth muscle regeneration, reducing excessive collagen deposition, and accelerating re-epithelialization and neovascularization. Taken together, the newly developed multifunctional PCA/SIS patch provides a promising candidate for urethral regeneration.

Simulation of the female pelvic mobility and vesical pressure changes employing fluid-structure interaction method.

INTRODUCTION AND HYPOTHESIS: This study aims to develop a fluid-structural interaction (FSI) method to pinpoint the effects of pressure changes inside the bladder and their impact on the supporting structure and the urethra mobility. METHODS: A physiological model of the nulliparous female pelvis, including the organs, supportive structures, and urine, was developed based on magnetic resonance images. Soft tissues with nonlinear hyperelastic material characteristics were modeled. The Navier-Stokes equations governing the fluid flow within the computational domain (urine) were solved. The urine and soft tissue interactions were simulated by the FSI method. The vesical pressure and its impact on the urethral mobility and supportive structures were investigated during the Valsalva maneuver. Moreover, the simulation results were validated by comparing with a urodynamic test and other research. RESULTS: The results demonstrated that the vesical pressure simulated by the FSI method could predict the nonlinear behavior of the urodynamic test pressure. The urethra retropubic bladder neck and the bladder neck-pubic bone angle changed 58.92% and -55.76%, respectively. The retropubic urethral length distance changed by -48.74%. The error compared to the statistical results of other research is < 5%. CONCLUSIONS: The total deformation and mobility of the urethra predicted by the FSI model were consistent with clinical observations in a subject. The urethra supports dependence on the tissues' mechanical properties, interaction between the tissues, and effect of urine fluid inside the bladder. This simulation effectively depicts the patterns of urethra mobility, which provides a better understanding of the behavior of the pelvic floor.

High-density spinal cord stimulation selectively activates lower urinary tract nerves.

Objective.Epidural spinal cord stimulation (SCS) is a potential intervention to improve limb and autonomic functions, with lumbar stimulation improving locomotion and thoracic stimulation regulating blood pressure. Here, we asked whether sacral SCS could be used to target the lower urinary tract (LUT) and used a high-density epidural electrode array to test whether individual electrodes could selectively recruit LUT nerves.Approach. We placed a high-density epidural SCS array on the dorsal surface of the sacral spinal cord and cauda equina of anesthetized cats and recorded the stimulation-evoked activity from nerve cuffs on the pelvic, pudendal and sciatic nerves.Main results. Here we show that sacral SCS evokes responses in nerves innervating the bladder and urethra and that these nerves can be activated selectively. Sacral SCS always recruited the pelvic and pudendal nerves and selectively recruited both of these nerves in all but one animal. Individual branches of the pudendal nerve were always recruited as well. Electrodes that selectively recruited specific peripheral nerves were spatially clustered on the arrays, suggesting anatomically organized sensory pathways.Significance.This selective recruitment demonstrates a mechanism to directly modulate bladder and urethral function through known reflex pathways, which could be used to restore bladder and urethral function after injury or disease.

Mild thermal stimulation of the buttock skin increases urinary voiding efficiency in anesthetized rats.

In the present study, we examined the effects of mild thermal stimulation of the skin on voiding efficiency using urethane-anesthetized rats with reduced voiding efficiency. Spontaneous urination was induced by infusing saline. For each voiding, the voiding efficiency was calculated from the voided volume and the bladder capacity measured. A Peltier thermode was attached to the buttock skin to apply stimulation: cooling between to 25 °C and 35 °C, every 20 s throughout the saline infusion. The voiding efficiency was 29 ± 9 % (mean ± SD) before stimulation and increased significantly by 10-15 % during stimulation. During thermal stimulation, the maximum vesical pressure during micturition was unchanged, but the urethral relaxation duration was significantly prolonged. Applying local anesthesia to the stimulated skin area abolished the changes in voiding efficiency in response to thermal stimulation. These results suggest that the excitation of cutaneous thermoreceptive afferents modulates urethral function during urination, thereby improving voiding efficiency.

Enhanced visualization of female squirting.

INTRODUCTION: Squirting is the involuntary expulsion of fluid from the female urethra following stimulation of the anterior vaginal wall before or during orgasm. The mechanism underlying squirting has not been established. PURPOSE: To elucidate the mechanism of squirting. METHODS: The subjects in the current study were women who were able to squirt. They were not sex workers. A urethral catheter was inserted before sexual stimulation and the bladder was emptied. Then, a mixture of indigo carmine (10 ml) and saline (40 ml) was injected into the bladder. Sexual stimulation was provided to facilitate squirting, which was videotaped and verified. The secretions were collected in sterile cups, and prostate specific antigen (PSA) and glucose levels were measured. RESULTS: Five women (2 in the 30s, 2 in the 40s, and 1 in the 50s) participated in this study. All women were able to squirt; three squirted only with manual sexual stimulation and two with penetrative sexual stimulation. The discharged fluid was blue in all cases, confirming the bladder as the source. The fluid was PSA-positive in four patients. CONCLUSIONS: The main component of squirt fluid is urine, but may also contain fluid from Skene's glands (female prostate). This is the first report in which visualization of squirting was enhanced.

Pressure transmission theory-The Rasputin of incontinence.

BACKGROUND: Enhorning's pressure transmission theory (PTT), though mortally wounded by multiple invalidations from the 1990 Integral Theory of female urinary incontinence (IT), like Rasputin, continues to survive as a theory for continence and incontinence. AIM: To examine the questions: How has the PTT survived? What is its contribution to knowledge? METHODS: Eleven different invalidations are presented based on images, pressure readings, clinical examples, experiments by the author, and others, for example, flow mechanics, finite element models, and surgical operations. RESULTS: Each of the 11 invalidations prima facie invalidate the PTTs of enhorning and others. CONCLUSIONS: "How has the PTT survived?" Having provided a plausible explanation for all abdominal stress urinary incontinence operations since 100 years, PTT, unsurprisingly, like climate change today, had become an entrenched convention which abdicated the need for midurethral sling (MUS) surgeons to learn the very different functional surgical anatomy underlying the MUS. "Has the PTT progressed knowledge, or retarded it?" This lack of knowledge by the surgeons of how and why the MUS works could be held responsible for the large number of major complications reported by the TVT: including, transected urethras, obturator nerve damage, perforation of external iliac vessels, more than 20 deaths. The role of the sling is to strengthen the pubourethral neoligament to prevent the urethra opening out under stress, not to elevate it. Elevating the sling remains the major cause of the most frequent complication of the MUS today, postoperative urinary retention.

Locomotor Exercise Enhances Supraspinal Control of Lower-Urinary-Tract Activity to Improve Micturition Function after Contusive Spinal-Cord Injury.

The recovery of lower-urinary-tract activity is a top priority for patients with spinal-cord injury. Historically, locomotor training improved micturition function in both patients with spinal cord injury and animal models. We explore whether training augments such as the supraspinal control of the external urethral sphincter results in enhanced coordination in detrusor-sphincter activity. We implemented a clinically relevant contusive spinal-cord injury at the 12th thoracic level in rats and administered forced wheel running exercise for 11 weeks. Awake rats then underwent bladder cystometrogram and sphincter electromyography recordings to examine the micturition reflex. Subsequently, pseudorabies-virus-encoding red fluorescent protein was injected into the sphincter to trans-synaptically trace the supraspinal innervation of Onuf's motoneurons. Training in the injury group reduced the occurrence of bladder nonvoiding contractions, decreased the voiding threshold and peak intravesical pressure, and shortened the latency of sphincter bursting during voiding, leading to enhanced voiding efficiency. Histological analysis demonstrated that the training increased the extent of spared spinal-cord tissue around the epicenter of lesions. Compared to the group of injury without exercise, training elicited denser 5-hydroxytryptamine-positive axon terminals in the vicinity of Onuf's motoneurons in the cord; more pseudorabies virus-labeled or c-fos expressing neurons were detected in the brainstem, suggesting the enhanced supraspinal control of sphincter activity. Thus, locomotor training promotes tissue sparing and axon innervation of spinal motoneurons to improve voiding function following contusive spinal-cord injury.

Age is associated with reduced urethral pressure and afferent activity in rat.

Age-related changes in the lower urinary tract (LUT) can affect the coordination of reflexes and increase the incidence of bladder disorders in elderly. This study examines the age-related loss of urethral signaling capability by measuring the afferent activity directly. We find that less urethral pressure develops in response to fluid flow in old rats compared to young rats and that pressure and flow evoke less urethral afferent activation. These findings are consistent with our previous study demonstrating that the urethra-to-bladder reflex, which is required for efficient voiding, becomes weaker with age. We measured the pudendal afferent response in young (4-7 months) and old (18-24 months) rats to fluid flow in the urethra across a range of flow rates. We used paraffin embedding and hematoxylin and eosin staining to quantify age-related changes in the sensory branch of the pudendal nerve. Urethral afferent signaling in response to the same urethral flow rates was weaker in older animals. That is, the sensitivity of urethra afferents to flow decreased with age, and higher flow rates were required in older animals to recruit urethra afferents. There was also a reduction in the myelin thickness of pudendal afferents in old rats, which is a possible contributing factor to the sensory activity. Furthermore, the same flow rates evoked less pressure in the urethras of old animals, indicating there is an age-related change of the urethral tissue that reduces the pressure stimulus to which these afferents respond. These results help characterize the underlying changes in LUT system with age.

Learned control of urinary reflexes in cattle to help reduce greenhouse gas emissions.

Indiscriminate voiding of excreta by cattle contributes to greenhouse gas (GHG) emissions and soil and water contamination1,2. Emissions are higher in animal-friendly husbandry offering cattle more space2 - a trade-off we call the 'climate killer conundrum'. Voiding in a specific location (latrine) would help resolve this dilemma by allowing ready capture and treatment of excreta under more spacious farming conditions. For urination, toileting requires self-control and coordination of a complex chain of behaviors including awareness of bladder fullness, overriding of excretory reflexes, selection of a latrine and intentional relaxation of the external urethral sphincter3. Attempts to train toileting in cattle have so far been only partly successful4-6, even though their excretion and associated neurophysiological control are similar to those in species capable of toileting3. Similarly, very young infants have been considered incapable of self-initiated voiding, but they can be taught with extensive training7. Using a backward chaining, reward-based training procedure, we here show that cattle can control their micturition reflex and use a latrine for urination. Such self-control provides evidence that animals can learn to respond to and reveal internal experiences via appropriately trained operant behaviors, thereby providing another way to explore their subjective states.

Efficacy of Sphincter Control Training and medical device in the treatment of premature ejaculation: A multicenter randomized controlled clinical trial.

A new line of treatment for premature ejaculation (PE) based on the use of masturbation aid device in combination with behavioral techniques has emerged in recent years. We report a multicenter randomized clinical trial with a parallel group design to determine the effectiveness of an electronic device called Myhixel I© in the treatment of PE. Forty patients who met the criteria for the diagnosis of lifelong PE, were assigned to two treatment groups completed the Sphincter control training (SCT) program in eight weeks. The only difference between groups was the use of the device. The main measure was the "fold increase" (FI) of the intravaginal ejaculatory latency time (IELT). The geometric means of IELT show, at the end of the treatment at week 8, a superiority of the device group. The mean FI 4.27 (SD 2.59) at the end of treatment for the device group was clearly higher than obtained in the previous clinical trial, in which a specific medical device was not used. No side effects were observed and it required little therapeutic input and no partner involvement. The SCT program in combination with the Myhixel I© is an effective treatment for PE.

Anatomy of Cowper's gland in humans suggesting a secretion and emission mechanism facilitated by cooperation of striated and smooth muscles.

This study presents the detailed anatomy of the Cowper's gland in humans. Elucidating the mechanism of secretion and emission of the Cowper's gland requires analysis of the muscles around the Cowper's gland. We hypothesized that the Cowper's gland involves not only smooth muscle but also the striated muscles of the pelvic floor. Here, we provide comprehensive and three-dimensional anatomy of the Cowper's gland and its surrounding structures, which overcomes the current local and planar understanding. In this study, seven male corpses of body donors were used to conduct macroscopic anatomy, histology, and three-dimensional reconstruction. The Cowper's gland was surrounded laterally and posterosuperiorly by striated and smooth muscles, respectively. The striated muscle bundle was connected from the superficial transverse perineal muscle, levator ani, and external anal sphincter to the external urethral sphincter (rhabdosphincter). The smooth muscle was part of the deep transverse perineal muscle and entered between the bilateral Cowper's glands and lobules. Our findings indicate that the secretion and emission of the Cowper's gland in humans are carried out through the cooperation of striated and smooth muscles.

Transurethral versus suprapubic catheterization to test urethral function in rats.

Transurethral and suprapubic catheterization have both been used to test urethral function in rats; however, it is unknown whether these methods affect urethral function or if the order of catheterization affects the results. The aim of this cross-over designed experiment was to compare the effects of catheterization methods and order on leak point pressure (LPP) testing. LPP and simultaneous external urethral sphincter electromyography (EUS EMG) were recorded in anesthetized female virgin Sprague-Dawley rats in a cross-over design to test the effects of transurethral and suprapubic catheterization. There was no significant difference in peak bladder pressure during LPP testing whether measured with a transurethral or suprapubic catheter. There was no significant difference in peak bladder pressure between the first and second catheter insertions. However, peak EMG firing rate, as well as peak EMG amplitude and EMG amplitude difference between peak and baseline were significantly higher after the first catheter insertion compared to the second insertion, regardless of the catheter method. Our results suggest that route of catheterization does not alter urethral function, e.g. create a functional partial outlet obstruction. Either catheterization method could be used for LPP and/or EUS EMG testing in rats.

Development of epithelial cholinergic chemosensory cells of the urethra and trachea of mice.

Cholinergic chemosensory cells (CCC) are infrequent epithelial cells with immunosensor function, positioned in mucosal epithelia preferentially near body entry sites in mammals including man. Given their adaptive capacity in response to infection and their role in combatting pathogens, we here addressed the time points of their initial emergence as well as their postnatal development from first exposure to environmental microbiota (i.e., birth) to adulthood in urethra and trachea, utilizing choline acetyltransferase (ChAT)-eGFP reporter mice, mice with genetic deletion of MyD88, toll-like receptor-2 (TLR2), TLR4, TLR2/TLR4, and germ-free mice. Appearance of CCC differs between the investigated organs. CCC of the trachea emerge during embryonic development at E18 and expand further after birth. Urethral CCC show gender diversity and appear first at P6-P10 in male and at P11-P20 in female mice. Urethrae and tracheae of MyD88- and TLR-deficient mice showed significantly fewer CCC in all four investigated deficient strains, with the effect being most prominent in the urethra. In germ-free mice, however, CCC numbers were not reduced, indicating that TLR2/4-MyD88 signaling, but not vita-PAMPs, governs CCC development. Collectively, our data show a marked postnatal expansion of CCC populations with distinct organ-specific features, including the relative impact of TLR2/4-MyD88 signaling. Strong dependency on this pathway (urethra) correlates with absence of CCC at birth and gender-specific initial development and expansion dynamics, whereas moderate dependency (trachea) coincides with presence of first CCC at E18 and sex-independent further development.

The urethra in continence and sensation: Neural aspects of urethral function.

AIMS: Traditionally, the urethra has been considered a mere conduit to guide urine from the bladder to the external side of the body. Building evidence indicates that the urethra may directly influence bladder function via mechanisms restricted to the lower urinary tract (LUT). METHODS: Here, we discuss the tissue arrangement of the urethra and addressed the contribution of new paraneuronal cells to LUT function. We also briefly reviewed two frequent LUT pathologies associated with urethral dysfunction. RESULTS: Continence depends on an intact and functional urethral sphincter, composed of smooth, and striated muscle fibers and regulated by somatic and autonomic fibers. Recent studies suggest the existence of an urethro-vesical reflex that also contributes to normal LUT function. Indeed, the urethral lumen is lined by a specialized epithelium, the urothelium, in the proximal urethra. In this region, recent evidence demonstrates the presence of specific paraneuronal cells, expressing the neurotransmitters acetylcholine and serotonin. These cells are in close proximity of nerve fibers coursing in the lamina propria and are able to release neurotransmitters and rapidly induce detrusor contractions, supporting the existence of an urethro-vesical crosstalk. CONCLUSION: The mechanism underlying the fast communication between the urethra and thebladder are beginning to be understood and should involve the interaction between specificepithelial cells and fibres innervating the urethral wall. It is likely that this reflex should bealtered in pathological conditions, becoming an attractive therapeutic target.

Transperineal ultrasound as a reliable tool in the assessment of membranous urethra length in radical prostatectomy patients.

To evaluate the usefulness of transperineal ultrasound (TPUS) as a method of membranous urethra length (MUL) measurement and investigate whether preoperative (MULpre) and postoperative (MULpost) would be associated with the degree and time of urinary continence recovery after laparoscopic radical prostatectomy (LRP). 84 patients who underwent LRP between January 2017 and December 2018 were selected for final analysis. All patients had preoperative and postoperative measurement of MUL in TPUS. Urinary continence was defined as no pad or a safety pad. Recovery of continence was assessed at 1, 3, 6 and 12 months after catheter removal. We prospectively analyzed correlation of MULpre, MULpost and a percent change in membranous urethral length (MULratio) with the urinary continence status. 69 (82%) patients regained continence in the follow-up of 12 months. MULpre, MULpost and MULratio assessed in TPUS were larger in subgroups of patients who regained continence earlier and in the entire continent group. Spearman rank test showed strong correlations between MULpost and MULratio (R-0.6 and R-0.56, respectively, p < 0.0001) with the time to continence recovery in the cumulative 12 months follow-up. TPUS allowed a reliable measurement of MUL before and after LRP. MULpre, MULpost as well as MULratio are related with time to regain continence and recovery rate after LRP. Sparing longest possible sphincteric urethra, with respect to oncological outcomes is a key factor in recovering continence after prostate cancer surgery.

Choice of cystometric technique impacts detrusor contractile dynamics in wistar rats.

The objective of the current animal study was to investigate factors contributing to the different phases of the cystometrogram (CMG) in order to address disparities in research data reported in the current literature. Three experiments in 20 female Wistar rats were designed to investigate (1) the effects of anesthesia on the contractile pattern of the bladder during micturition; (2) the impact of the physical characteristics of the CMG technique upon the accuracy of intra-vesical pressure recordings; and (3) identification of physiological and methodological factors associated with the emptying and rebound phases during CMG. Variables tested included awake versus urethane-anesthetized conditions, use of a single catheter for both filling and intra-vesical pressure (Pves) recording versus a separate two catheter approach, and comparisons between ureter, bladder dome, and urethral catheter placements. Both awake and anesthetized conditions contributed to variations in the shape and magnitude of the CMG pressure curves. In addition, catheter size, acute incision of the bladder dome for catheter placement, use of the same catheter for filling and Pves recordings, as well as the placement and positioning of the tubing, all contributed to alterations of the physiological properties and characteristic of the various CMG phases, including the frequent occurrence of an artificial rebound during the third phase of micturition. The present results demonstrate how different experimental conditions lead not only to variability in Pves curves, but consistency of the measurements as well, which needs to be accounted for when interpreting CMG outcome data.

Changes in urethral smooth muscle and external urethral sphincter function with age in rats.

To confirm changes in urethral activity with age, both intravesical pressure and urethral perfusion pressure (UPP) were recorded and external urethral sphincter electromyography (EUS-EMG) was performed. A total of 33 female Sprague Dawley rats aged 3 months (young rats), 12 months (middle-aged rats), and 24 months (aged rats) were used. Bladder activity was evaluated using continuous cystometry. Urethral activity was evaluated by simultaneously recording intravesical pressure and UPP in isovolumetric conditions under urethane anesthesia in each group. Additionally, EUS-EMG activity was monitored under the same conditions. In continuous cystometry, the amplitude of bladder contractions was not different among the three groups; nevertheless, residual urine volume was significantly increased in middle-aged and aged rats, as compared in young rats. With respect to UPP, the change in UPP was significantly smaller in aged rats (60%) and middle-aged rats (64%) than in young rats. Furthermore, the mean amplitude of high-frequency oscillations of the EUS was significantly lower in aged (61%) and middle-aged rats (70%) than in young rats. EUS-EMG revealed EUS bursting activity during voiding with clear active and silent phases in young rats but unclear active and silent phases in aged rats. Masson's trichrome staining of the urethra showed EUS atrophy in aged rats compared to young and middle-aged rats. The results indicate that aging induces two urethral dysfunctions in the urethral smooth muscle and EUS, which may lead to dyscoordination between the urinary bladder and urethra.