Neurophysiology and therapeutic receptor targets for stress urinary incontinence

Efficacy of Electroacupuncture in the Treatment of Mild to Moderate Female Stress Urinary Incontinence: Protocol for a Systematic Review and Network Meta-Analysis

BACKGROUND

Stress urinary incontinence (SUI), the most common form of urinary incontinence, is a condition that affects many women. It is characterized by involuntary urine leakage during activities that increase abdominal pressure, such as sneezing, coughing, or physical exertion, according to the International Continence Society. SUI affects patients' quality of life and causes depression and emotional disorders, which negatively influences physical and mental health. The participants in the studies in this review comprised women with mild to moderate SUI, because there are more female patients than male patients, and most patients with severe SUI are treated surgically. Moreover, after retrieval, there were no systematic reviews or network meta-analyses (NMAs) of conservative treatments, such as electroacupuncture (EA), in women with mild to moderate SUI.

OBJECTIVE

This study aims to investigate the efficacy of electroacupuncture among women with mild to moderate SUI using an NMA.

METHODS

Randomized clinical trials related to conservative treatments for SUI will be searched in 5 English and 3 Chinese literature databases: EMBASE, PubMed, Cochrane, Web of Science, ClinicalTrials.gov, Chinese National Knowledge Infrastructure (CNKI), WanFang, and the Chinese BioMedical Literature Database. The search period for these 8 electronic databases will be from 2002 to 2022. The PROSPERO database and the International Platform of Registered Systematic Review and Meta-Analysis Protocols (INPLASY) database will also be searched. Two reviewers will independently complete the research selection. After screening the studies, 2 other researchers will extract the data, and the quality of the included studies will be evaluated according to the quality standards specified in the Cochrane Collaboration Tool (version 2). The primary outcomes will be the change in urine leakage determined by a 1-hour pad test and International Consultation on Incontinence Questionnaire Short Form (ICIQ-SF) scores at baseline and at the conclusion of the follow-up. The secondary outcomes will be 72-hour incontinence episodes, residual bladder volume, effective rate, urodynamic indexes, and other reported measurements. Stata (version 14.0; StataCorp) and Review Manager (RevMan version 5.3; Cochrane) will be implemented for data synthesis and meta-analysis.

RESULTS

The results are not yet accessible because this is a protocol for a systematic review and meta-analysis. The protocol was registered on INPLASY on February 22, 2023. By April 6, 2023, we had completed the literature search of the 8 databases and completed the selection and data extraction of the articles.

CONCLUSIONS

The results of this systematic review will demonstrate the efficacy of EA among women with mild to moderate SUI. The results will provide evidence for clinicians and guideline makers to choose suitable treatments for SUI.

TRIAL REGISTRATION

International Platform of Registered Systematic Review and Meta-Analysis Protocols (INPLASY) 202320098; https://inplasy.com/inplasy-2023-2-0098/.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/55870.

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.

Differentiation of patient-specific void urine-derived human induced pluripotent stem cells to fibroblasts and skeletal muscle myocytes

Cell-based therapy is a major focus for treatment of stress urinary incontinence (SUI). However, derivation of primary cells requires tissue biopsies, which often have adverse effects on patients. A recent study used human induced pluripotent stem cells (iPSC)-derived smooth muscle myocytes for urethral sphincter regeneration in rats. Here, we establish a workflow using iPSC-derived fibroblasts and skeletal myocytes for urethral tissue regeneration: (1) Cells from voided urine of women were reprogrammed into iPSC. (2) The iPSC line U1 and hESC line H9 (control) were differentiated into fibroblasts expressing FSP1, TE7, vinculin, vimentin, αSMA, fibronectin and paxillin. (3) Myogenic differentiation of U1 and H9 was induced by small molecule CHIR99021 and confirmed by protein expression of myogenic factors PAX7, MYOD, MYOG, and MF20. Striated muscle cells enriched by FACS expressed NCAM1, TITIN, DESMIN, TNNT3. (4) Human iPSC-derived fibroblasts and myocytes were engrafted into the periurethral region of RNU rats. Injected cells were labelled with ferric nanoparticles and traced by Prussian Blue stain, human-specific nuclear protein KU80, and human anti-mitochondria antibody. This workflow allows the scalable derivation, culture, and in vivo tracing of patient-specific fibroblasts and myocytes, which can be assessed in rat SUI models to regenerate urethral damages and restore continence.

Advances in the molecular pathogenesis and cell therapy of stress urinary incontinence

Stress urinary incontinence (SUI) is very common in women. It affects patients' mental and physical health, and imposed huge socioeconomic pressure. The therapeutic effect of conservative treatment is limited, and depends heavily on patient persistence and compliance. Surgical treatment often brings procedure-related adverse complications and higher costs for patients. Therefore, it is necessary to better understand the potential molecular mechanisms underlying stress urinary incontinence and develop new treatment methods. Although some progress has been made in the basic research in recent years, the specific molecular pathogenic mechanisms of SUI are still unclear. Here, we reviewed the published studies on the molecular mechanisms associated with nerves, urethral muscles, periurethral connective tissue and hormones in the pathogenesis of SUI. In addition, we provide an update on the recent progresses in research on the use of cell therapy for treating SUI, including research on stem cells therapy, exosome differentiation and gene regulation.

Effect of Electroacupuncture Added to Pelvic Floor Muscle Training in Women with Stress Urinary Incontinence: A Randomized Clinical Trial

BACKGROUND

Pelvic floor muscle training (PFMT) is a first-line conservative therapy for stress urinary incontinence (SUI). Electroacupuncture (EA) has been used to treat SUI recently.

OBJECTIVE

To compare the effectiveness of PFMT + EA versus PFMT + sham EA for SUI in women.

DESIGN, SETTING, AND PARTICIPANTS

A prospective, multicenter, randomized, controlled clinical trial was conducted at four hospitals in China involving 304 women with SUI from May 20, 2014 to November 21, 2017. Data were analyzed from April 20 to December 21, 2018.

INTERVENTION

Participants were randomized to receive 8 wk of PFMT+ EA (n = 154) or PFMT + sham EA (n = 150).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome was the change in the amount of urine leakage measured on a 1-hr pad test. Student's t test, the χ² test, and the Wilcoxon rank-sum test were used for data analysis.

RESULTS AND LIMITATIONS

Among the 304 participants randomized, 286 completed the study. The mean age was 57.6 yr (standard deviation [SD] 8.9) for the PFMT + sham EA group and 57.2 yr (SD 9.1) for the PFMT + EA group. The mean urine leakage at baseline was 13.6 g for the PFMT + sham EA group and 13.9 g for the PFMT + EA group. After the 8-wk intervention, the PFMT + EA group had a greater decrease in mean urine leakage (-9.8 g) than the PFMT + sham EA group (-5.8 g) with a mean difference of 4.0 g (95% confidence interval [CI] 0.8-7.2). Significantly more patients experienced a ≥50% reduction in urine leakage and the mean number of incontinence episodes in 24 h in the PFMT + EA group than in the PFMT + sham EA group (26.3%, 95%CI 15.8-36.8%). The PFMT + EA group experienced better improvement in participant-reported SUI severity at 6 wk (p < 0.001) and 8 wk (p < 0.001) and self-evaluated therapeutic effects at 2-32 wk (p < 0.001) after the intervention. Lack of measurement of the amount of urine leakage during follow-up is a limitation.

CONCLUSIONS

In this randomized clinical trial, 8-wk combined treatment with PFMT + EA led to a greater improvement in SUI symptoms and better outcomes than with PFMT + sham EA.

PATIENT SUMMARY

We evaluated the effectiveness and safety of pelvic floor muscle training combined with electroacupuncture for stress urinary incontinence in women, Our results show that this is a promising therapeutic approach for the treatment of stress urinary incontinence.

Increasing Effects of Selective 5-Hydroxytryptamine Type 2C Receptor Stimulation on Evoked Momentary Urethral Closure in Female Rats and Humans

Under healthy conditions, more than one urethra-closing reflex, including both bladder afferent-independent and -dependent actions, function during momentary elevation of intravesical (bladder) pressure to prevent urinary incontinence. In the current study, the effects of a novel selective 5-hydroxytryptamine type 2C (5-HT2C) receptor agonist, TAK-233, on evoked momentary urethra-closing functions were investigated in female rats and humans to elucidate 5-HT2C receptor functions. In anesthetized female rats, TAK-233 dose-dependently and significantly increased urethral resistance during sneezing in rats with distended vaginas and bilaterally transected pelvic nerves. The drug also dose-dependently and significantly increased urethral resistance during momentary intravesical pressure elevation by electrical stimulation of abdominal muscles in rats with a transected spinal cord at the T8-T9 level and intact pelvic nerves. The increased effects observed during electrical stimulation were abolished by either an intravenously administered selective 5-HT2C receptor antagonist, SB 242084, or bilateral transection of the pelvic nerves or somatic nerves innervating the external urethral sphincter and pelvic floor muscles. In the spinal cord-transected and pelvic nerve-intact rats, TAK-233 enlarged the urethra-closing responses induced by both passive and abrupt intravesical pressure elevation, measured by a microtip transducer located in the middle urethra. Additionally, the effects of TAK-233 on the stimulus threshold of urethral contractile responses induced by transcranial magnetic stimulation were investigated in healthy female volunteers. The drug dose-dependently and significantly lowered this stimulus threshold, indicating an increased sensitivity of the response. These results demonstrate that 5-HT2C receptor stimulation enhances the evoked momentary urethra-closing functions in both female rats and humans. SIGNIFICANCE STATEMENT: 5-hydroxytryptamine (serotonin) type 2C (5-HT2C) receptor stimulation by TAK-233 enhanced urethral resistance in rats during an evoked momentary event in which the bladder afferent-independent or -dependent reflex functions via striated muscle-mediated mechanisms. The increases in sensitivity of transcranial magnetic stimulation-evoked urethral contractile responses in healthy female subjects indicates that this mechanism also functions in humans. The evoked momentary conditions activating these reflexes provide a suitable model to demonstrate the effects of 5-HT2C receptor stimulation.

Neurophysiological control of urinary bladder storage and voiding-functional changes through development and pathology

The effective storage of urine and its expulsion relies upon the coordinated activity of parasympathetic, sympathetic, and somatic innervations to the lower urinary tract (LUT). At birth, all mammalian neonates lack the ability to voluntary regulate bladder storage or voiding. The ability to control urinary bladder activity is established as connections to the central nervous system (CNS) form through development. The neural regulation of the LUT has been predominantly investigated in adult animal models where comparatively less is known about the neonatal and postnatal neurophysiological development that facilitate urinary continence. Furthermore, congenital neurological or anatomical defects can adversely affect both storage and voiding functions through postnatal development and into adulthood, leading to secondary conditions including vesicoureteral reflux, chronic urinary tract infections, and end-stage renal disease. Therefore, the aim of the review is to provide the current knowledge available on neurophysiological regulation of the LUT through pre- to postnatal development of human and animal models and the consequences of congenital anomalies that can affect LUT neural function.

Role of Ano1 Ca2+-activated Cl- channels in generating urethral tone

Urinary continence is maintained in the lower urinary tract by the contracture of urethral sphincters, including smooth muscle of the internal urethral sphincter. These contractions occlude the urethral lumen, preventing urine leakage from the bladder to the exterior. Over the past 20 years, research on the ionic conductances that contribute to urethral smooth muscle contractility has greatly accelerated. A debate has emerged over the role of interstitial cell of Cajal (ICC)-like cells in the urethra and their expression of Ca²⁺-activated Cl^- channels encoded by anoctamin-1 [Ano1; transmembrane member 16 A (Tmem16a) gene]. It has been proposed that Ano1 channels expressed in urethral ICC serve as a source of depolarization for smooth muscle cells, increasing their excitability and contributing to tone. Although a clear role for Ano1 channels expressed in ICC is evident in other smooth muscle organs, such as the gastrointestinal tract, the role of these channels in the urethra is unclear, owing to differences in the species (rabbit, rat, guinea pig, sheep, and mouse) examined and experimental approaches by different groups. The importance of clarifying this situation is evident as effective targeting of Ano1 channels may lead to new treatments for urinary incontinence. In this review, we summarize the key findings from different species on the role of ICC and Ano1 channels in urethral contractility. Finally, we outline proposals for clarifying this controversial and important topic by addressing how cell-specific optogenetic and inducible cell-specific genetic deletion strategies coupled with advances in Ano1 channel pharmacology may clarify this area in future studies.NEW & NOTEWORTHY Studies from the rabbit have shown that anoctamin-1 (Ano1) channels expressed in urethral interstitial cells of Cajal (ICC) serve as a source of depolarization for smooth muscle cells, increasing excitability and tone. However, the role of urethral Ano1 channels is unclear, owing to differences in the species examined and experimental approaches. We summarize findings from different species on the role of urethral ICC and Ano1 channels in urethral contractility and outline proposals for clarifying this topic using cell-specific optogenetic approaches.

Electroacupuncture for stress-predominant mixed urinary incontinence: a protocol for a three-armed randomised controlled trial

INTRODUCTION

Evidence specific for stress-predominant mixed urinary incontinence is still lacking at present, and acupuncture may relieve the symptoms. We plan to conduct this multi-centre, three-armed, randomised controlled trial to investigate the efficacy and safety of electroacupuncture among women with stress-predominant mixed urinary incontinence.

METHODS AND ANALYSIS

The trial will be conducted at five hospitals in China. Two hundred thirty-two eligible women will be randomly assigned (2:1:1) to the electroacupuncture, sham electroacupuncture or waiting-list group to receive either 24-session acupuncture/sham acupuncture treatment over 8 weeks and 24-week follow-up or 20-week watchful waiting. The primary outcome is the proportion of participants with at least 50% reduction in mean 24-hour stress incontinence episode frequencies from baseline to week 8. The outcome will be analysed with the intention to treatpopulation (defined as participants randomised) with a two-sided p value of less than 0.05 considered significant.

ETHICS AND DISSEMINATION

The protocol has been approved by Guang'anmen Hospital Institutional Review Board (2019-241-KY). Detailed information of the trial will be informed to the participants, and written informed consent will be obtained from every participant. Results of the trial are expected to be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT04299932).

The diversity of neuronal phenotypes in rodent and human autonomic ganglia

Selective sympathetic and parasympathetic pathways that act on target organs represent the terminal actors in the neurobiology of homeostasis and often become compromised during a range of neurodegenerative and traumatic disorders. Here, we delineate several neurotransmitter and neuromodulator phenotypes found in diverse parasympathetic and sympathetic ganglia in humans and rodent species. The comparative approach reveals evolutionarily conserved and non-conserved phenotypic marker constellations. A developmental analysis examining the acquisition of selected neurotransmitter properties has provided a detailed, but still incomplete, understanding of the origins of a set of noradrenergic and cholinergic sympathetic neuron populations, found in the cervical and trunk region. A corresponding analysis examining cholinergic and nitrergic parasympathetic neurons in the head, and a range of pelvic neuron populations, with noradrenergic, cholinergic, nitrergic, and mixed transmitter phenotypes, remains open. Of particular interest are the molecular mechanisms and nuclear processes that are responsible for the correlated expression of the various genes required to achieve the noradrenergic phenotype, the segregation of cholinergic locus gene expression, and the regulation of genes that are necessary to generate a nitrergic phenotype. Unraveling the neuron population-specific expression of adhesion molecules, which are involved in axonal outgrowth, pathway selection, and synaptic organization, will advance the study of target-selective autonomic pathway generation.

Urethral dysfunction in a rat model of chemically induced prostatic inflammation: potential involvement of the MRP5 pump

Prostate inflammation (PI) is a clinical condition associated with infection and/or inflammation of the prostate. It is a common disease frequently associated to lower urinary tract (LUT) symptoms. The urethra is an understudied structure in the LUT and plays a fundamental role in the urinary cycle. Here, we proposed to evaluate the effect of PI on the urethra tissue. Male Sprague-Dawley rats were used, and PI was induced by formalin injection into the ventral lobes of the prostate. The pelvic urethra at the prostatic level was harvested for histological analysis, contraction (electrical field stimulation and phenylephrine), and relaxation (sodium nitroprusside/MK-571) experiments. Various gene targets [cytochrome c oxidase subunit 2, transforming growth factor-β₁, interleukin-1β, hypoxia-inducible factor-1α, α_1A-adrenoceptor, inositol 1,4,5-trisphosphate receptor type 1, voltage-gated Ca²⁺ channel subunit-α_1D, neuronal nitric oxide synthase, soluble guanylyl cyclase, phosphodiesterase 5A, protein kinase CGMP-dependent 1, and multidrug resistance-associated protein 5 (MRP5; ATP-binding cassette subfamily C member 5)] were quantified, and cGMP levels were measured. No histological changes were detected, and functional assays revealed decreased contraction and increased relaxation of urethras from the PI group. The addition of MK-571 to functional assays increased urethral relaxation. Genes associated with inflammation were upregulated in urethras from the PI group, such as cytochrome oxidase c subunit 2, transforming growth factor-β₁, interleukin-1β, and hypoxia-inducible factor-1α. We also found increased expression of L-type Ca²⁺ channels and the neuronal nitric oxide synthase enzyme and decreased expression of the MRP5 pump. Finally, cGMP production was enhanced in urethral tissue of PI animals. The results indicate that PI is associated with proinflammatory gene expression in the urethra without histologically evident inflammation and that PI produces a dysfunctional urethra and MRP5 pump downregulation, which results in cGMP accumulation inside the cell. These findings would help to better understand LUT dysfunctions associated with PI and the role of MRP pumps in the control of LUT function.

Therapeutic effects and modulatory mechanism of Alpiniae oxyphyllae Fructus in chronic intermittent hypoxia induced enuresis in rats

OBJECTIVE

The objective of this study was to explore the effect of Alpiniae oxyphyllae Fructus (AOF) on a rat model of chronic intermittent hypoxia (CIH)-induced enuresis. Findings of this study may help identify therapeutic targets in children with nocturnal enuresis (NE).

METHODS

Female rats were randomly divided into a control group (saline gavage, 4 weeks of normal air), CIH group (saline gavage, 4 weeks of CIH), and AOF group (AOF gavage, 4 weeks of CIH). The variables measured in this study included water intake, urine output, bladder leak point pressure (BLPP), malondialdehyde (MDA) levels, and superoxide dismutase (SOD) activity. The expression levels of the purinergic P₂X₃ receptor, muscarinic M₃ receptor, and ß₃-adrenergic receptor (ß₃-AR) in the bladder were also measured. The bladder was subjected to haematoxylin and eosin (HE) and Weigert staining, and histological changes were observed under a light microscope to evaluate the morphological changes in the bladder in each group.

RESULTS

Compared with the control group, urine output was increased, and the BLPP was decreased in the CIH group, but AOF administration decreased urine output and increased BLPP. In addition, the serum MDA level increased and the SOD activity decreased in the CIH group compared with the control group. Administration of AOF decreased the MDA level and increased the SOD activity. Additionally, compared with the control group, HE and Weigert staining in the CIH group showed that the bladder detrusor muscle bundles were disordered and loose, some muscle bundles were broken, the content of collagen fibres in the gap was reduced, and the gap was significantly widened. However, following the administration of AOF, the bladder detrusor muscle bundles were neatly arranged, and the content of collagen fibres in the gap was increased. Furthermore, compared with the control group, the purinergic P₂X₃ receptor and muscarinic M₃ receptor were expressed at higher levels, and ß₃-AR was expressed at lower levels in the CIH group, but AOF administration decreased the expression of the purinergic P₂X₃ receptor and muscarinic M₃ receptor and increased the expression of the ß₃-AR.

CONCLUSIONS

AOF improves enuresis by inhibiting oxidative stress and regulating the expression of the purinergic P₂X₃ receptor, muscarinic M₃ receptor, and ß₃ adrenergic receptor.

[Overview of pharmacological mechanisms controlling micturition in the central nervous system]

The functions of the lower urinary tract, to storage and periodically release urine, are dependent on the activity of smooth and striated muscles in the bladder, urethra and external urethral sphincter. This activity is in turn controlled by neural circuits not only in the periphery, but also in the central nervous system (CNS). During urine storage, the outlet is closed and the bladder smooth muscle is quiescent by the neural control mechanism mainly organized in the spinal cord. When bladder volume reaches the micturition threshold, activation of a micturition center in the dorsolateral pons (the pontine micturition center) induces micturition through activation of sacral parasympathetic (pelvic) nerves. The brain rostral to the pons (diencephalon and cerebral cortex) is also involved in excitatory and inhibitory regulation of the micturition reflex. Various transmitters including dopamine, serotonin, norepenephrine, GABA, excitatory and inhibitory amino acids, opioids and acetylcholine are implicated in the modulation of the micturition reflex in the CNS. Therefore, injury or neurodegenerative diseases of the CNS as well as drugs can produce bladder and urethral dysfunctions such as urinary frequency, urgency and incontinence or inefficient bladder emptying.

[Therapeutic new targets for stress urinary incontinence in the central nervous system]

Stress urinary incontinence (SUI) is a common and bothersome problem among middle-aged women. However, there are few useful drugs for SUI. Urethral hypermobility and intrinsic sphincter deficiency are two main causes of SUI. Various animal models of SUI, such as vaginal distention, pudendal nerve injury, or ovariectomy, have been developed to study the pathophysiology of SUI. In addition, we have previously reported that cerebral infarction rats also induce SUI. Leak point pressure measurements are the most commonly used methods to evaluate the urethral dysfunction in SUI animal models. Originally, we have developed microtransducer-tipped catheter measurements of urethral activity during sneezing. Previous or our basic research has clarified potential strategies for pharmacotherapy of SUI in the central nervous system. Therapeutic targets include adrenergic and serotonergic (5-HT) receptors in the spinal cord, which stimulate pudendal nerve innervating the external urethral sphincter and/or sympathetic nerve innervating urethral smooth muscle. Activation of α₁-adrenoceptors, 5-HT_2C, or 5-HT₇ receptors enhances the reflex at the spinal cord level whereas pre- or postsynaptic α₂-adrenoceptors and/or 5-HT_1A receptors inhibit the reflex. We have recently reported that stimulation of the spinal μ-opioid receptors by tramadol also enhances the reflex. Thus, we review the recent advances in basic SUI research and potential targets for pharmacotherapy of SUI in the central nervous system.

Responsiveness of lumbosacral superficial dorsal horn neurons during the voiding reflex and functional loss of spinal urethral-responsive neurons in streptozotocin-induced diabetic rats

AIMS

Sensory information from the lower urinary tract (LUT) is conveyed to the spinal cord to trigger and co-ordinate micturition. However, it is not fully understood how spinal dorsal horn neurons are excited during the voiding reflex. In this study, we developed an in vivo technique allowing recording of superficial dorsal horn (SDH) neurons concurrent with intravesical pressure (IVP) during the micturition cycle in both normal and diabetic rats.

METHODS

Lumbosacral dorsal horn neuronal activity and IVP were recorded from urethane-anesthetized naive and streptozotocin (STZ)-induced diabetic rats. Saline was continuously perfused into the urinary bladder through a cannula to induce micturition.

RESULTS

We classified SDH neurons into bladder- and urethral-responsive neurons, based on their responsiveness during the voiding reflex. Bladder-responsive SDH neurons responded to the rapid increase in IVP at the start of voiding. In contrast, urethral-responsive SDH neuronal firing increased at the peak IVP and their firing lasted during the voiding phase (the high-frequency oscillations). Urethral-responsive SDH neurons were more sensitive to capsaicin, received C afferent fiber inputs, and were rarely detected in STZ-diabetes rats. Administration of a cyclohexenoic long-chain fatty alcohol (TAC-302), which is reported to promote neurite outgrowth of peripheral nerves in STZ-diabetic rats, prevented the functional loss of spinal urethral response.

CONCLUSIONS

Sensory information from the bladder and urethra is conveyed separately to different groups of SDH neurons. Functional loss of spinal urethral sensory information through unmyelinated C afferent fibers may contribute to diabetic bladder dysfunction.

Treatment of urinary incontinence after total hysterectomy with acupuncture: A case report

RATIONALE

Acupuncture is a significant feature of traditional Chinese medicine, which can dredge the channels, harmonize qi and blood, replenish deficiency and relieve excess, strengthen the body and remove pathogens to treat urinary incontinence after hysterectomy, and improve the quality of life, which is simple, convenient, inexpensive, and practical.

PATIENT CONCERNS

After a total hysterectomy, the catheter was retained every day, causing urinary incontinence and elderly urine wetness for 30 days.

DIAGNOSES

Postoperative urinary incontinence for 1 month; type 2 diabetes for 4 years. Hypertension for 2 years.

INTERVENTIONS

From the first month after operation, acupuncture on bilateral, Ciliao (BL32), Zhongliao (BL33), and Xialiao (BL34).

OUTCOMES

The patient experienced bladder fullness on the 2nd day. On the 3rd day, the patient could arose from bed and urinated on her own. On the 4th day, she could urinate freely. The time and frequency of urination were normal.

LESSONS

acupuncture is safe and effective mode for the treatment of urinary incontinence issues after total hysterectomy. It greatly improves the quality of life and daily wellbeing.

Effect of artificial urinary sphincter implantation on erectile function and sexual satisfaction

Artificial urinary sphincter (AUS) implantation is the gold standard treatment in total stress urinary incontinence (SIU). Our aim is to evaluate the effect of AUS implantation on erectile function and sexual satisfaction (SS). Fourteen patients aged 58-73 years (mean: 66.92 ± 4.51 years) who underwent AUS implantation by a perineal approach between May 2015 and April 2018 were included in our study. Patients with neurogenic disease or very low or no erectile function and those who underwent non-nerve-sparing radical prostatectomy were excluded. Erectile function and intercourse satisfaction were evaluated pre-operatively and post-operatively at 6-month follow-up using international index of erectile function (IIEF) questionnaires. After AUS implantation; eight patients were totally dry, four achieved social continence (less than one pad/day), and two still had SUI (two or more pads/day). Mean pre- and post-operative IIEF values of the patients were 16.14 ± 3.18 and 17.42 ± 4.43 respectively. Mean pre- and post-operative SS values were 8.57 ± 1.78 and 8.71 ± 2.19 respectively. There was no statistically significant difference between pre- and post-operative IIEF-5 and intercourse satisfaction scores (p > 0.05). Although we did not see a significant effect of AUS implantation in our study, in SIU patients, coital incontinence or unpleasant odour during intercourse can lead to sexual avoidance and reduced SS, and AUS implantation may improve SS.

Dopaminergic urethral closure mechanisms in a rat model of Parkinson's disease

AIMS

Urinary incontinence is prevalent among patients with Parkinson's disease (PD). In the present study, we investigated urethral functions in a rat model of PD induced by 6-hydroxydopamine injection at their substantia nigra pars compacta as well as the roles of selective agonists/antagonist of dopamine D1- and D2-like receptors in active urethral closure mechanisms.

METHODS

We measured changes in the urethral pressure amplitude during electrical stimulation, urethral baseline pressure, and leak point pressure after intravenous administration of selective agonists or antagonists of the dopamine D1- and D2-like receptors in a rat model of PD.

RESULTS

The mean leak point pressure and the mean active urethral response values were significantly smaller for the untreated PD rat group compared with the control group. In PD model, the active urethral response increased significantly after treatment with the dopamine D1-like receptor agonist, whereas that induced by the dopamine D2-like receptor agonist decreased significantly. The response to the D2-like receptor agonist was suppressed in the PD rat by the dopamine D2-like receptor antagonist.

CONCLUSION

Our results suggest that the active urethral closure mechanisms are significantly impaired when dopamine is depleted. In the PD rat, dopamine D1-like receptor activity on the central nervous system appear to partially compensate for urethral functions negatively impacted by the lack of dopamine, whereas dopamine D2-like receptor activity might exacerbate urinary leakage owing to the negative effect of this activated receptor on urethral pressure under increased intra-abdominal pressure.

Role of the serotonergic system in urethral continence reflexes during sneezing in rats

To clarify the role of serotonin (5-HT) in the prevention of stress urinary incontinence (SUI) during sneezing, we investigated the effect of intraperitoneal application of p-chlorophenylalanine (PCPA; a serotonin synthesis inhibitor) and intravenous application of CP-809101 (a 5-HT_2C agonist) or LP44 (a 5-HT₇ agonist) using female rats, in which the neurally evoked continence reflex during sneezing was examined. Amplitudes of urethral pressure response during sneezing (A-URS), urethral baseline pressure (UBP) at the middle urethra, and sneeze-induced leak point pressure (S-LPP) were measured in normal female adult rats with or without drug administration. PCPA decreased A-URS by 35.1 cmH₂O and UBP by 13.3 cmH₂O compared with normal rats. In PCPA-administrated rats, CP-809101 increased A-URS by 24.1 cmH₂O and UBP by 15.1 cmH₂O, and LP44 also increased A-URS by 20.6 cmH₂O and UBP by 11.4 cmH₂O compared with rats treated with PCPA alone. SUI was observed with S-LPP of 40.1 cmH₂O in PCPA-administrated rats, in which CP-809101 and LP44 increased S-LPP by 28.0 and 15.2 cmH₂O, respectively, compared with rats treated with PCPA alone. The effects of CP-809101 and LP44 were antagonized by SB-242084 (a selective 5-HT_2C antagonist) and SB-269970 (a selective 5-HT₇ antagonist), respectively. These results indicate that activation of 5-HT receptors enhances the active urethral closure reflex during sneezing, at least in part via 5-HT_2C and 5-HT₇ receptors.

Possible role of hyposensitivity of C-fiber afferents at the proximal urethra in the development of urge urinary incontinence in patients with detrusor overactivity

OBJECTIVE

The aim of the present study was to investigate associations between urethral sensation and urge urinary incontinence (UUI) in patients with and without detrusor overactivity (DO).

METHODS

The medical records of 80 consecutive patients who underwent filling cystometry and urethral current perception threshold (CPT) tests were examined retrospectively. Following the exclusion of 4 patients not eligible for analysis, patients were classified into neurogenic DO, idiopathic DO, or DO-negative groups based on neurological and cystometric findings (n = 30, 12, and 34, respectively). Eleven DO-negative patients were defined as normal controls on cystometrograms (CMG) using the following exclusion criteria: bladder compliance <12.5 mL/cmH₂ O, volume >275 mL at first filling sensation, and comorbidities possibly affecting lower urinary tract function. Thus, 53 patients were finally included in the study. Proximal urethral CPT was evaluated with intraurethral square-wave stimulation at 3 Hz to activate C-fiber afferents.

RESULTS

Median CPT was higher in neurogenic and idiopathic DO than in the normal CMG group (11.3 and 9.0 vs. 2.8 mA, respectively; P < .05), as well as in patients with UUI (n = 19) compared with non-UUI patients (n = 34; 12.5 vs. 5.4 mA, respectively; P < .05). The proportion of UUI patients was significantly greater in the DO-positive groups than in the normal CMG group (P < .05). CPTs were not associated with bladder capacity at the first filling sensation (r = 0.11).

CONCLUSION

Hyposensitive C-fibers of the proximal urethra may contribute to the development of urodynamic DO as well as UUI in patients complaining of lower urinary tract symptoms.

Effect of Electroacupuncture on Urinary Leakage Among Women With Stress Urinary Incontinence: A Randomized Clinical Trial

Importance

Electroacupuncture involving the lumbosacral region may be effective for women with stress urinary incontinence (SUI), but evidence is limited.

Objective

To assess the effect of electroacupuncture vs sham electroacupuncture for women with SUI.

Design, Setting, and Participants

Multicenter, randomized clinical trial conducted at 12 hospitals in China and enrolling 504 women with SUI between October 2013 and May 2015, with data collection completed in December 2015.

Interventions

Participants were randomly assigned (1:1) to receive 18 sessions (over 6 weeks) of electroacupuncture involving the lumbosacral region (n = 252) or sham electroacupuncture (n = 252) with no skin penetration on sham acupoints.

Main Outcomes and Measures

The primary outcome was change from baseline to week 6 in the amount of urine leakage, measured by the 1-hour pad test. Secondary outcomes included mean 72-hour urinary incontinence episodes measured by a 72-hour bladder diary (72-hour incontinence episodes).

Results

Among the 504 randomized participants (mean [SD] age, 55.3 [8.4] years), 482 completed the study. Mean urine leakage at baseline was 18.4 g for the electroacupuncture group and 19.1 g for the sham electroacupuncture group. Mean 72-hour incontinence episodes were 7.9 for the electroacupuncture group and 7.7 for the sham electroacupuncture group. At week 6, the electroacupuncture group had greater decrease in mean urine leakage (-9.9 g) than the sham electroacupuncture group (-2.6 g) with a mean difference of 7.4 g (95% CI, 4.8 to 10.0; P < .001). During some time periods, the change in the mean 72-hour incontinence episodes from baseline was greater with electroacupuncture than sham electroacupuncture with between-group differences of 1.0 episode in weeks 1 to 6 (95% CI, 0.2-1.7; P = .01), 2.0 episodes in weeks 15 to 18 (95% CI, 1.3-2.7; P < .001), and 2.1 episodes in weeks 27 to 30 (95% CI, 1.3-2.8; P < .001). The incidence of treatment-related adverse events was 1.6% in the electroacupuncture group and 2.0% in the sham electroacupuncture group, and all events were classified as mild.

Conclusions and Relevance

Among women with stress urinary incontinence, treatment with electroacupuncture involving the lumbosacral region, compared with sham electroacupuncture, resulted in less urine leakage after 6 weeks. Further research is needed to understand long-term efficacy and the mechanism of action of this intervention.

Trial Registration

clinicaltrials.gov Identifier: NCT01784172.

How important is the α1-adrenoceptor in primate and rodent proximal urethra? Sex differences in the contribution of α1-adrenoceptor to urethral contractility

Urethral smooth muscle (USM) contributes to urinary continence by contracting during the urine storage phase, which is mainly mediated by activation of postjunctional α₁-adrenoceptors. Males and females show differences in the functioning of the lower urinary tract and the most common urinary tract symptoms (LUTS). LUTS in men typically occur in association with bladder outlet obstruction, whereas in women urinary urge-incontinence symptoms are more common. Therefore, this study aimed to evaluate sex differences in α₁-adrenoceptor subtype expression and their importance in proximal urethra contraction in the mouse (C57BL6/J) and marmoset (Callithrix jacchus). Contractile responses to phenylephrine, norepinephrine, potassium chloride (KCl), and electrical-field stimulation (EFS) were evaluated. Phenylephrine, norepinephrine, KCl, and EFS produced markedly greater contractions in male mice and marmoset USM compared with females. The sex differences remained unchanged by N^ω-nitro-l-arginine (l-NAME; nitric oxide synthase inhibitor), atropine (muscarinic receptor antagonist), and PPADS (P2X1-purinoceptor antagonist). Additionally, selective α_1A (but not α_1B- and α_1D-)-adrenoceptor antagonists significantly reduced phenylephrine-induced USM contractions. qRT-PCR for α_1A-, _B-, and _D-adrenoceptor subtypes revealed a marked presence of the α_1A-adrenoceptor subtype in male USM, but not females. Male mouse urethra also exhibited a higher tyrosine hydroxylase mRNA expression. Histomorphometric analysis showed a greater USM area in male than female mice. In conclusion, male mouse and marmoset proximal USM shows strong α_1A- adrenoceptor-induced contractions and abundant α_1A-adrenoceptor expression, whereas α_1A-adrenoceptor-mediated mechanisms are much less important in females. The differential expression of α₁-adrenoceptors in the proximal urethra may contribute to the higher incidence of urinary incontinence in women and obstructed voiding in men.

Smooth Muscle Progenitor Cells Derived From Human Pluripotent Stem Cells Induce Histologic Changes in Injured Urethral Sphincter

: Data suggest that myoblasts from various sources, including bone marrow, skeletal muscle, and adipose tissue, can restore muscle function in patients with urinary incontinence. Animal data have indicated that these progenitor cells exert mostly a paracrine effect on the native tissues rather than cell regeneration. Limited knowledge is available on the in vivo effect of human stem cells or muscle progenitors on injured muscles. We examined in vivo integration of smooth muscle progenitor cells (pSMCs) derived from human pluripotent stem cells (hPSCs). pSMCs were derived from a human embryonic stem cell line (H9-ESCs) and two induced pluripotent stem cell (iPSC) lines. pSMCs were injected periurethrally into urethral injury rat models (2 × 10⁶ cells per rat) or intramuscularly into severe combined immunodeficiency mice. Histologic and quantitative image analysis revealed that the urethras in pSMC-treated rats contained abundant elastic fibers and thicker muscle layers compared with the control rats. Western blot confirmed increased elastin/collagen III content in the urethra and bladder of the H9-pSMC-treated rats compared with controls. iPSC-pSMC treatment also showed similar trends in elastin and collagen III. Human elastin gene expression was not detectable in rodent tissues, suggesting that the extracellular matrix synthesis resulted from the native rodent tissues rather than from the implanted human cells. Immunofluorescence staining and in vivo bioluminescence imaging confirmed long-term engraftment of pSMCs into the host urethra and the persistence of the smooth muscle phenotype. Taken together, the data suggest that hPSC-derived pSMCs facilitate restoration of urethral sphincter function by direct smooth muscle cell regeneration and by inducing native tissue elastin/collagen III remodeling.

SIGNIFICANCE

The present study provides evidence that a pure population of human smooth muscle progenitor cells (pSMCs) derived from human pluripotent stem cells (hPSCs) (human embryonic stem cells and patient induced pluripotent stem cells) restores urethral sphincter function by two mechanisms: modulation of extracellular matrix protein metabolism in vivo and pSMC proliferation and differentiation into smooth muscle cells to regenerate the muscle layer in the lower urinary tract. These findings on the in vivo effects of human pSMCs should aid in optimizing regenerative therapies using human myoblasts.

A Pilot Randomized Placebo Controlled Trial of Electroacupuncture for Women with Pure Stress Urinary Incontinence

BACKGROUND

Acupuncture is a potential conservative therapy for women with stress urinary incontinence (SUI). There is limited evidence to support its effectiveness due to the poor quality of existing studies.

METHODS

We performed a pilot randomized, controlled trial to preliminarily assess the efficacy of electroacupuncture (EA) in women with pure SUI. A total of 80 women with pure SUI were randomly assigned to receive EA with deep needling at BL33 and BL35 (n = 40) or sham EA with non-penetrating needling at sham acupoints (n = 40) three sessions per week for 6 weeks. The women were followed for 24 weeks. The primary outcome was the change from baseline in the amount of urine leakage measured by a 1-hour pad test after 6 weeks. The secondary outcomes included the 72-hour incontinence episode frequency (IEF), International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF) score, and patient self-evaluation of therapeutic effect. Adverse events (AEs) were monitored throughout the trial.

RESULTS

The median decrease from baseline of urine leakage measured by the 1-hour pad test was 2.5 g [interquartile range (IQR): 1.80-14.6 in the EA group, which was greater than the median decrease of 0.05 g (IQR: -2.80-+0.50) in the sham EA group after 6 weeks (p<0.01). The differences between groups in the decrease from baseline of 72-hour IEF became statistically significant at week 30 with a median decrease of 3.25 g (IQR: 1.25-5.69) in the EA group, and a median decrease of 1.00 g (IQR: -0.69-+2.88) in the sham EA group (p = 0.01). The participants in the EA group showed greater decreases in ICIQ-SF score and higher ratings in the help they received from the treatment than those in the sham EA group at weeks 6,18 and 30 (all p<0.05). No obvious AEs were observed in either group.

CONCLUSION

EA may effectively and safely relieve urinary incontinence symptoms and improve quality of life in women with pure SUI. EA demonstrated more than a placebo effect. Since this is a pilot study, results should be interpreted with caution.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02445573.

Differential expression of microRNAs in periurethral vaginal wall tissues of postmenopausal women with and without stress urinary incontinence

OBJECTIVE

The aims of this study were to investigate microRNA (miRNA) expression profiles in the periurethral vaginal wall tissues of postmenopausal women with and without stress urinary incontinence (SUI) and to explore the putative target genes associated with SUI via miRNA-messenger RNA (mRNA) pair prediction.

METHODS

Periurethral vaginal wall tissues of postmenopausal women with SUI (n = 13) and matched continent postmenopausal women (n = 13) were collected during transvaginal surgical operation. Total RNAs were extracted and miRNAs were profiled by TaqMan Array Human MicroRNA assays in three case-control pairs. TargetScanS, PicTar, and miRanda were used to obtain the putative miRNA-mRNA pairs based on sequence data, and three pairs were predicated. The relative expression levels of miRNAs in predicated miRNA-mRNA pairs were quantified in 10 other case-control pairs by real-time polymerase chain reaction. The expression levels of mRNAs and corresponding proteins were estimated via real-time polymerase chain reaction and Western blot analysis.

RESULTS

Twelve miRNAs were identified to be differentially expressed between two groups: the significantly up-regulated let-7a, miR-101#, miR-125b-2#, miR-190b, and miR-892b, and the down-regulated miR-124, miR-330-3p, miR-485-3p, miR-517b, miR-523, miR-589, and miR-93#. Moreover, three miRNA-mRNA pairs of interest were established via computational algorithms: miR-124 and growth factor receptor-bound protein 2; miR-330-3p and bicaudal D homolog 2; and miR-93# and signal transducer and activator of transcription 3. The expression levels of the three miRNAs were quantified, and a reduction in SUI was revealed. On the other hand, increased expression levels of predicated mRNAs and their protein products were detected.

CONCLUSIONS

This study reports the differential expression of 12 miRNAs in SUI and predicates three miRNA-mRNA pairs. Interestingly, all three predicated target genes are associated with neurodegenerative conditions, indicating the potential significance of neurodegenerative mechanisms in the etiology of SUI.

Regenerative medicine as a new therapeutic strategy for lower urinary tract dysfunction

The use of regenerative medicine for the treatment of organic and functional disorders intractable to conventional treatment has increased worldwide. This innovative medical field might particularly hold promise for the treatment of life-threatening diseases or healing of irreplaceable organs, such as the heart, liver and brain. Dysfunction of the urogenital tract and associated organs other than the kidney might not have immediate life-threatening implications; furthermore, the effectiveness of alternative therapy, such as enterocystoplasty for bladder cancer, has been shown. Therefore, most physicians or scientists do not give much importance to these disorders. However, urological disease has increased in developed societies in recent years. Furthermore, medical costs have also escalated. Disorders of the lower urinary tract, such as urinary disturbance or incontinence, can lead to other complications, impairing quality of life and ultimately increasing short- and long-term medical expenses. Regenerative medicine might hold potential solutions to these problems. Recent advances in urogenital regenerative medicine are reviewed in the present article, with particular reference to lower urinary tract reconstruction. The potential of regenerative medicine for the treatment of intractable lower urinary tract dysfunction compared with conventional treatment is also discussed.

Pathophysiology of urinary incontinence in murine models

Urethral closure mechanisms under stress conditions consist of passive urethral closure involving connective tissues, fascia and/or ligaments in the pelvis and active urethral closure mediated by hypogastric, pelvic and pudendal nerves. Furthermore, we have previously reported that the active urethral closure mechanism might be divided into two categories: (i) the central nervous control passing onto Onuf's nucleus under sneezing or coughing; and (ii) the bladder-to-urethral spinal reflex under Valsalva-like stress conditions, such as laughing, exercise or lifting heavy objects. There are over 200 million people worldwide with urinary incontinence, a condition that is associated with a significant social impact and reduced quality of life. Therefore, basic research for urinary continence mechanisms in response to different stress conditions can play an essential role in developing treatments for stress urinary incontinence. It has been clinically shown that the etiology of stress urinary incontinence is divided into urethral hypermobility and intrinsic sphincter deficiency, which could respectively correspond to passive and active urethral closure dysfunction. In this review, we summarize the representative stress urinary incontinence animal models and the methods to measure leak point pressures under stress conditions, and then highlight stress-induced urinary continence mechanisms mediated by active urethral closure mechanisms, as well as future pharmacological treatments of stress urinary incontinence. In addition, we introduce our previous reports including sex differences in urethral closure mechanisms under stress conditions and urethral compensatory mechanisms to maintain urinary continence after pudendal nerve injury in female rats.