Neural control of the lower urinary tract

The long-lasting post-stimulation inhibitory effects of bladder activity induced by posterior tibial nerve stimulation in unanesthetized rats

Tibial nerve stimulation (TNS) is one of the neuromodulation methods used to treat an overactive bladder (OAB). However, the treatment mechanism is not accurately understood owing to significant differences in the results obtained from animal and clinical studies. Thus, this study was aimed to confirm the response of bladder activity to the different stimulation frequencies and to observe the duration of prolonged post-stimulation inhibitory effects following TNS. This study used unanesthetized rats to provide a closer approximation of the clinical setting and evaluated the changes in bladder activity in response to 30 min of TNS at different frequencies. Moreover, we observed the long-term changes of post-stimulation inhibitory effects. Our results showed that bladder response was immediately inhibited after 30 min of 10 Hz TNS, whereas it was excited at 50 Hz TNS. We also used the implantable stimulator to observe a change in duration of the prolonged post-stimulation inhibitory effects of the TNS and found large discrepancies in the time that the inhibitory effect lasted after stimulation between individual animals. This study provides important evidence that can be used to understand the neurophysiological mechanisms underlying the bladder inhibitory response induced by TNS as well as the long-lasting prolonged post-stimulation effect.

[Brain death criterion and organ donation: current neuroscientific perspective]

In der akademischen und öffentlichen Debatte wird der irreversible Hirnfunktionsausfall als Kriterium des Todes (Hirntodkriterium) immer wieder hinterfragt. Im vorliegenden Artikel werden 6 prototypische Thesen gegen das Hirntodkriterium diskutiert: 1) Nichtsuperiorität des Gehirns gegenüber anderen Organen, 2) Unsicherheit der Hirntoddiagnostik, 3) erhaltene Schmerzempfindung Hirntoter, 4) (spontane) sexuelle Reifung und erhaltene Reproduktionsfunktion Hirntoter, 5) Symmetrie von Hirntod und Embryonalphase, 6) Gleichsetzung des intensivmedizinisch erhaltenen Restorganismus Hirntoter mit dem lebenden Menschen.

Keine dieser Thesen hält einer kritischen Analyse stand. In Deutschland wird das Ganzhirntodkriterium angewendet. Der Hirntod geht mit dem völligen Ausfall jeglicher Empfindung, Bewusstheit, Mimik, Augen‑, Zungen- und Schlundmotorik, Willkürmotorik und Sexualfunktion einher (funktionelle „Enthauptung“). Medizinisch-technisch können andere Organe bzw. ihre Primitivsteuerung ersetzt werden, nicht aber das Gehirn. Das Gehirn, nicht der Körper, ist bestimmend für das menschliche Individuum. Die Gleichsetzung des künstlich erhaltenen Restorganismus, naturphilosophisch als lebendiges System interpretierbar, mit dem Organismus desselben lebenden Menschen wird durch die beliebige Reduzierbarkeit der Anzahl beteiligter Organe ad absurdum geführt. Der irreversible Hirnfunktionsausfall führt unausweichlich zum Herzstillstand, unbehandelt innerhalb von Minuten, unter Intensivtherapie i. d. R. innerhalb von Tagen. Auch beim Embryo/Fötus führt die Fehlanlage des gesamten Gehirns zum (vorgeburtlichen) Tod. Die in Deutschland gesetzliche Richtlinie zur Hirntodfeststellung hat eine im internationalen Vergleich hohe Diagnosesicherheit, es sind damit keine bestätigten Fehldiagnosen aufgetreten.

Bladder and Bowel Management in Dogs With Spinal Cord Injury

Spinal cord injury in companion dogs can lead to urinary and fecal incontinence or retention, depending on the severity, and localization of the lesion along the canine nervous system. The bladder and gastrointestinal dysfunction caused by lesions of the autonomic system can be difficult to recognize, interpret and are easily overlooked. Nevertheless, it is crucial to maintain a high degree of awareness of the impact of micturition and defecation disturbances on the animal's condition, welfare and on the owner. The management of these disabilities is all the more challenging that the autonomic nervous system physiology is a complex topic. In this review, we propose to briefly remind the reader the physiology of micturition and defecation in dogs. We then present the bladder and gastrointestinal clinical signs associated with sacral lesions (i.e., the L7-S3 spinal cord segments and nerves) and supra-sacral lesions (i.e., cranial to the L7 spinal cord segment), largely in the context of intervertebral disc herniation. We summarize what is known about the natural recovery of urinary and fecal continence in dogs after spinal cord injury. In particular we review the incidence of urinary tract infection after injury. We finally explore the past and recent literature describing management of urinary and fecal dysfunction in the acute and chronic phase of spinal cord injury. This comprises medical therapies but importantly a number of surgical options, some known for decades such as sacral nerve stimulation, that might spark some interest in the field of spinal cord injury in companion dogs.

Pain in Endometriosis

Endometriosis is a chronic and debilitating condition affecting ∼10% of women. Endometriosis is characterized by infertility and chronic pelvic pain, yet treatment options remain limited. In many respects this is related to an underlying lack of knowledge of the etiology and mechanisms contributing to endometriosis-induced pain. Whilst many studies focus on retrograde menstruation, and the formation and development of lesions in the pathogenesis of endometriosis, the mechanisms underlying the associated pain remain poorly described. Here we review the recent clinical and experimental evidence of the mechanisms contributing to chronic pain in endometriosis. This includes the roles of inflammation, neurogenic inflammation, neuroangiogenesis, peripheral sensitization and central sensitization. As endometriosis patients are also known to have co-morbidities such as irritable bowel syndrome and overactive bladder syndrome, we highlight how common nerve pathways innervating the colon, bladder and female reproductive tract can contribute to co-morbidity via cross-organ sensitization.

Establishment of animal model manifested as bladder neurogenic changes generated by bilateral pelvic nerve injury in male rats

PURPOSE

To establish a male rat model of neurogenic bladder after bilateral pelvic nerve injury (BPNI) and investigate the factors associated with onset of neurogenic bladder.

METHODS

Twenty-four 8-week-old male Sprague-Dawley rats were randomly divided into three groups (n = 8 rats per group). Rats in 4-week and 8-week nerve injury group underwent BPNI, while rats in the sham group underwent a sham operation. Bladder functional analysis were performed and then bladders tissues were harvested for morphological examination and investigating the mRNA expression levels of target genes in all rats.

RESULTS

The bladder weight significantly increased in rats following BPNI. Functional analysis revealed non-voiding contractions and decreased detrusor contractility following BPNI, manifested as elevated post-void residual and bladder capacity while reduced maximum voiding pressure and voiding efficiency. The collagen area in bladder tissue and mRNA expression levels of target genes significantly increased at 4 or 8 weeks post-BPNI except Smad3. At 4 weeks post-BPNI, expression levels of vesicular acetylcholine transporter were reduced, then returned to baseline at 8 weeks. Expression levels of tyrosine hydroxylase were reduced at both 4 and 8 weeks post-BPNI.

CONCLUSIONS

A neurogenic bladder animal model was successfully established by performing BPNI in male rats, characterized by impaired voiding function, bladder detrusor fibrosis, and reduced neurotransmitter release.

The Urothelium: Life in a Liquid Environment

The urothelium, which lines the renal pelvis, ureters, urinary bladder, and proximal urethra, forms a high-resistance but adaptable barrier that surveils its mechanochemical environment and communicates changes to underlying tissues including afferent nerve fibers and the smooth muscle. The goal of this review is to summarize new insights into urothelial biology and function that have occurred in the past decade. After familiarizing the reader with key aspects of urothelial histology, we describe new insights into urothelial development and regeneration. This is followed by an extended discussion of urothelial barrier function, including information about the roles of the glycocalyx, ion and water transport, tight junctions, and the cellular and tissue shape changes and other adaptations that accompany expansion and contraction of the lower urinary tract. We also explore evidence that the urothelium can alter the water and solute composition of urine during normal physiology and in response to overdistension. We complete the review by providing an overview of our current knowledge about the urothelial environment, discussing the sensor and transducer functions of the urothelium, exploring the role of circadian rhythms in urothelial gene expression, and describing novel research tools that are likely to further advance our understanding of urothelial biology.

Sexual dimorphism of detrusor function demonstrated by urodynamic studies in rhesus macaques

The lower urinary tract (LUT) and micturition reflexes are sexually dimorphic across mammals. Sex as a biological variable is also of critical importance for the development and translation of new medical treatments and therapeutics interventions affecting pelvic organs, including the LUT. However, studies of LUT function with comparisons between the sexes have remained sparse, especially for larger mammals. Detrusor function was investigated by filling cystometry and pressure flow studies in 16 male and 22 female rhesus macaques. By filling cystometry, male subjects exhibited a significantly larger bladder capacity and compliance compared to females. Pressure flow studies showed a significantly higher bladder pressure at voiding onset, peak pressure, and elevation in detrusor-activated bladder pressure from the end of bladder filling to peak pressure in the male subjects. The activation of reflex micturition, with associated detrusor contractions, resulted in voiding in a significantly larger proportion of female compared to male subjects. A higher urethral outlet resistance is suggested in the male subjects. We conclude that sexual dimorphism of detrusor function is prominent in rhesus macaques, shares many features with the human, and merits consideration in translational and pre-clinical research studies of micturition and LUT function in non-human primates.

Relationship between Lower Urinary Tract Dysfunction and Dementia

Lower urinary tract dysfunction (LUTD) is a common health challenge in dementia patients with significant morbidity and socioeconomic burden. It often causes lower urinary tract (LUT) symptoms, restricts activities of daily life, and impairs quality of life. Among several LUT symptoms, urinary incontinence (UI) is the most prominent storage symptom in the later stages of dementia. UI in patients with dementia results not only from cognitive impairment, but also from urological defects such as detrusor overactivity. Management of LUTD in patients with dementia is based on multiple factors, including cognitive state, functional impairment, concurrent comorbidities, polypharmacy and urologic condition. Behavioral therapy under caregiver support represents appropriate treatment strategy for UI in these patients. Pharmacological treatment can be considered in patients refractory to behavioral therapy, but it is more effective when combined with behavioral therapy. Antimuscarinics and mirabegron, a beta-3 receptor agonist, are effective for managing storage symptoms involving the LUT. However, anticholinergic side effects in elderly subjects are a concern, particularly when there is a risk of exacerbating cognitive impairment with prolonged use of antimuscarinics. Proper recognition and treatment of LUTD in dementia can improve quality of life in these patients.

Detrusor Smooth Muscle KV7 Channels: Emerging New Regulators of Urinary Bladder Function

Relaxation and contraction of the urinary bladder smooth muscle, also known as the detrusor smooth muscle (DSM), facilitate the micturition cycle. DSM contractility depends on cell excitability, which is established by the synchronized activity of multiple diverse ion channels. K+ channels, the largest family of channels, control DSM excitability by maintaining the resting membrane potential and shaping the action potentials that cause the phasic contractions. Among the members of the voltage-gated K+ (KV) channel superfamily, KV type 7 (KV7) channels - KV7.1-KV7.5 members encoded by KCNQ1-KCNQ5 genes - have been recently identified as functional regulators in various cell types including vascular, cardiac, and neuronal cells. Their regulatory roles in DSM, however, are just now emerging and remain to be elucidated. To address this gap, our research group has initiated the systematic investigation of human DSM KV7 channels in collaboration with clinical urologists. In this comprehensive review, we summarize the current understanding of DSM Kv7 channels and highlight recent discoveries in the field. We describe KV7 channel expression profiles at the mRNA and protein levels, and further elaborate on functional effects of KV7 channel selective modulators on DSM excitability, contractility, and intracellular Ca2+ dynamics in animal species along with in vivo studies and the limited data on human DSM. Within each topic, we highlight the main observations, current gaps in knowledge, and most pressing questions and concepts in need of resolution. We emphasize the lack of systematic studies on human DSM KV7 channels that are now actively ongoing in our laboratory.

Animal Model for Lower Urinary Tract Dysfunction in Parkinson's Disease

Although Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra and subsequent motor symptoms, various non-motor symptoms often precede these other symptoms. While motor symptoms are certainly burdensome, a wide range of non-motor symptoms have emerged as the key determinant of the quality of life in PD patients. The prevalence of lower urinary tract symptoms differs according to the study, with ranges between 27% and 63.9%. These can be influenced by the stage of disease, the presence of lower urinary tract-related comorbidities, and parallels with other manifestations of autonomic dysfunction. Animal models can provide a platform for investigating the mechanisms of PD-related dysfunction and for the assessment of novel treatment strategies. Animal research efforts have been primarily focused on PD motor signs and symptoms. However, the etiology of lower urinary tract dysfunction in PD has yet to be definitively clarified. Several animal PD models are available, each of which has a different effect on the autonomic nervous system. In this article, we review the various lower urinary tract dysfunction animal PD models. We additionally discuss techniques for determining the appropriate model for evaluating the development of lower urinary tract dysfunction treatments.

Stem Cell Therapy for Neurogenic Bladder Dysfunction in Rodent Models: A Systematic Review

PURPOSE

Neurogenic bladder dysfunction (NGB) has an impact on the quality of life, which made it an important research subject in preclinical studies. The present review investigates the effect of stem cell (SC) therapy on bladder functional recovery after the onset of spinal cord injury (SCI), multiple sclerosis (MS), Parkinson disease (PD), and stroke in rodent models.

METHODS

All experiments evaluated the regenerative potential of SC on the management of NGB in rodent models up to June 2019, were included. From 1,189 relevant publications, 20 studies met our inclusion criteria of which 15 were conducted on SCI, 2 on PD, 2 on stroke, and 1 on MS in the rodent models. We conducted a meta-analysis on SCI experiments and for other neurological diseases, detailed urodynamic findings were reported.

RESULTS

The common SC sources used for therapeutical purposes were neural progenitor cells, bone marrow mesenchymal SCs, human amniotic fluid SCs, and human umbilical cord blood SCs. There was a significant improvement of micturition pressure in both contusion and transaction SCI models 4 and 8 weeks post-SC transplantation. Residual urine volume, micturition volume, and bladder capacity were improved 28 days after SC transplantation only in the transaction model of SCI. Nonvoiding contraction recovered only in 56 days post-cell transplantation in the contusion model.

CONCLUSION

Partial bladder recovery has been evident after SC therapy in SCI models. Due to limitations in the number of studies in other neurological diseases, additional studies are necessary to confirm the detailed mechanism for bladder recovery.

Cholinergic modulation of CRH and non-CRH neurons in Barrington's nucleus of the mouse

Corticotropin-releasing hormone (CRH) is expressed in Barrington's nucleus (BarN), which plays an essential role in the regulation of micturition. To control the neural activities of BarN, glutamatergic and GABAergic inputs from multiple sources have been demonstrated; however, it is not clear how modulatory neurotransmitters affect the activity of BarN neurons. We have employed knock-in mice, CRH-expressing neurons of which are labeled with a modified yellow fluorescent protein (Venus). Using whole cell patch-clamp recordings, we examined the responses of Venus-expressing (putative CRH-expressing) neurons in BarN (Bar^CRH), as well as non-CRH-expressing neurons (Bar^CRH-negative), following bath application of cholinergic agonists. According to the present study, the activity of Bar^CRH neurons could be modulated by dual cholinergic mechanisms. First, they are inhibited by a muscarinic receptor-mediated mechanism, most likely through the M2 subclass of muscarinic receptors. Second, Bar^CRH neurons are excited by a nicotinic receptor-mediated mechanism. Bar^CRH-negative neurons also responded to cholinergic agents. Choline transporter-immunoreactive nerve terminals were observed in close proximity to the neurites, as well as the somata of Bar^CRH. The present results suggest that BarN neurons are capable of responding to cholinergic input.NEW & NOTEWORTHY This study investigates the effects of bath-applied cholinergic agonists on Barrington's nucleus (BarN) neurons in vitro. They were either excitatory, through nicotinic receptors, or inhibitory, through muscarinic receptors. Putative corticotropin-releasing hormone (CRH)-expressing neurons in BarN, as well as putative non-CRH-expressing neurons, responded to cholinergic agonists.

Mechanosensitivity Is a Characteristic Feature of Cultured Suburothelial Interstitial Cells of the Human Bladder

Bladder dysfunction is characterized by urgency, frequency (pollakisuria, nocturia), and dysuria and may lead to urinary incontinence. Most of these symptoms can be attributed to disturbed bladder sensitivity. There is growing evidence that, besides the urothelium, suburothelial interstitial cells (suICs) are involved in bladder afferent signal processing. The massive expansion of the bladder during the filling phase implicates mechanical stress delivered to the whole bladder wall. Little is known about the reaction of suICs upon mechanical stress. Therefore, we investigated the effects of mechanical stimulation in cultured human suICs. We used fura-2 calcium imaging as a major physiological readout. We found spontaneous intracellular calcium activity in 75 % of the cultured suICs. Defined local pressure application via a glass micropipette led to local increased calcium activity in all stimulated suICs, spreading over the whole cell. A total of 51% of the neighboring cells in a radius of up to 100 µm from the stimulated cell showed an increased activity. Hypotonic ringer and shear stress also induced calcium transients. We found an 18-times increase in syncytial activity compared to unstimulated controls, resulting in an amplification of the primary calcium signal elicited in single cells by 50%. Our results speak in favor of a high sensitivity of suICs for mechanical stress and support the view of a functional syncytium between suICs, which can amplify and distribute local stimuli. Previous studies of connexin expression in the human bladder suggest that this mechanism could also be relevant in normal and pathological function of the bladder in vivo.

Cerebellum and micturition: what do we know? A systematic review

Aims

Micturition depends on a complex voluntary and involuntarily neuronal network located at various levels of the nervous system. The mechanism is highly dependent on the hierarchical organization of central nervous system pathways. If the role of the cortex and brainstem centres is well established, the role of other subcortical areas structures, such as the cerebellum is poorly understood. We are interested in discussing the current knowledge on the role of cerebellum in micturition.

Methods

A systematic search is performed in the medical literature, using the PubMed database with the keyword « cerebellum ». The latter is combined with «urination » OR « micturition » OR « urinary bladder ».

Results

Thirty-one articles were selected, focussing on micturition and describing the role of the cerebellum. They were grouped in 6 animal experimental studies, 20 functional brain imaging in micturition and 5 clinical studies.

Conclusions

Although very heterogeneous, experimental and clinical data clearly indicate the cerebellum role in the micturition control. Cerebellum modulates the micturition reflex and participates to the bladder sensory-motor information processing. The cerebellum is involved in the reflex micturition modulation through direct or indirect pathways to major brainstem or forebrain centres.

Urodynamic Assessment of Neuronal Intranuclear Inclusion Disease

Neuronal intranuclear inclusion disease (NIID) is a disease that causes leukoencephalopathy (dementia) and peripheral neuropathy (variable manifestation including bladder dysfunction). This is the first urodynamic report to show that bladder dysfunction in NIID is a combination of detrusor overactivity, decreased bladder sensation, large post-void residual, and neurogenic changes in the sphincter electromyogram. This report will help managing bladder dysfunction in NIID.

Transplanting neural progenitor cells to restore connectivity after spinal cord injury

Spinal cord injury remains a scientific and therapeutic challenge with great cost to individuals and society. The goal of research in this field is to find a means of restoring lost function. Recently we have seen considerable progress in understanding the injury process and the capacity of CNS neurons to regenerate, as well as innovations in stem cell biology. This presents an opportunity to develop effective transplantation strategies to provide new neural cells to promote the formation of new neuronal networks and functional connectivity. Past and ongoing clinical studies have demonstrated the safety of cell therapy, and preclinical research has used models of spinal cord injury to better elucidate the underlying mechanisms through which donor cells interact with the host and thus increase long-term efficacy. While a variety of cell therapies have been explored, we focus here on the use of neural progenitor cells obtained or derived from different sources to promote connectivity in sensory, motor and autonomic systems.

Ceftriaxone inhibits stress-induced bladder hyperalgesia and alters cerebral micturition and nociceptive circuits in the rat: A multidisciplinary approach to the study of urologic chronic pelvic pain syndrome research network study

AIMS

Emotional stress plays a role in the exacerbation and development of interstitial cystitis/bladder pain syndrome (IC/BPS). Given the significant overlap of brain circuits involved in stress, anxiety, and micturition, and the documented role of glutamate in their regulation, we examined the effects of an increase in glutamate transport on central amplification of stress-induced bladder hyperalgesia, a core feature of IC/BPS.

METHODS

Wistar-Kyoto rats were exposed to water avoidance stress (WAS, 1 hour/day x 10 days) or sham stress, with subgroups receiving daily administration of ceftriaxone (CTX), an activator of glutamate transport. Thereafter, cystometrograms were obtained during bladder infusion with visceromotor responses (VMR) recorded simultaneously. Cerebral blood flow (CBF) mapping was performed by intravenous injection of [¹⁴ C]-iodoantipyrine during passive bladder distension. Regional CBF was quantified in autoradiographs of brain slices and analyzed in three dimensional reconstructed brains with statistical parametric mapping.

RESULTS

WAS elicited visceral hypersensitivity during bladder filling as demonstrated by a decreased pressure threshold and VMR threshold triggering the voiding phase. Brain maps revealed stress effects in regions noted to be responsive to bladder filling. CTX diminished visceral hypersensitivity and attenuated many stress-related cerebral activations within the supraspinal micturition circuit and in overlapping limbic and nociceptive regions, including the posterior midline cortex (posterior cingulate/anterior retrosplenium), somatosensory cortex, and anterior thalamus.

CONCLUSIONS

CTX diminished bladder hyspersensitivity and attenuated regions of the brain that contribute to nociceptive and micturition circuits, show stress effects, and have been reported to demonstrated altered functionality in patients with IC/BPS. Glutamatergic pharmacologic strategies modulating stress-related bladder dysfunction may be a novel approach to the treatment of IC/BPS.

Sex differences in c-Fos and EGR-1/Zif268 activity maps of rat sacral spinal cord following cystometry-induced micturition

Storage and voiding of urine from the lower urinary tract (LUT) must be timed precisely to occur in appropriate behavioral contexts. A major part of the CNS circuit that coordinates this activity is found in the lumbosacral spinal cord. Immediate early gene (IEG) activity mapping has been widely used to investigate the lumbosacral LUT-related circuit, but most reports focus on the effects of noxious stimulation in anesthetized female rats. Here we use c-Fos and EGR-1 (Zif268) activity mapping of lumbosacral spinal cord to investigate cystometry-induced micturition in awake female and male rats. In females, after cystometry c-Fos neurons in spinal cord segments L5-S2 were concentrated in the sacral parasympathetic nucleus (SPN), dorsal horn laminae II-IV, and dorsal commissural nucleus (SDCom). Comparisons of cystometry and control groups in male and female revealed sex differences. Activity mapping suggested dorsal horn laminae II-IV was activated in females but showed net inhibition in males. However, inhibition in male rats was not detected by EGR-1 activity mapping, which showed low coexpression with c-Fos. A class of catecholamine neurons in SPN and SDCom neurons were also more strongly activated by micturition in females. In both sexes, most c-Fos neurons were identified as excitatory by their absence of Pax2 expression. In conclusion, IEG mapping in awake male and female rats has extended our understanding of the functional molecular anatomy of the LUT-related circuit in spinal cord. Using this approach, we have identified sex differences that were not detected by previous studies in anesthetized rats.

Lower urinary tract dysfunction in common neurological diseases

The lower urinary tract has the main function of urine storage and voiding. The integrity of the lower urinary tract nerve supply is necessary for its proper function. Neurological disorders can lead to lower urinary tract dysfunction (LUTD) and cause lower urinary tract symptoms (LUTS). Common causes of neurogenic LUTS or LUTD include spinal cord injury, multiple sclerosis, Parkinson's disease, cerebrovascular accidents, cauda equina syndrome, diabetes mellitus, and multiple system atrophy. The pathophysiology is categorized according to the nature of the onset of neurological disease. Assessment requires clinical evaluation, laboratory tests, imaging, and urodynamic studies. Impaired voiding is most often managed by clean intermittent self-catheterization if the postvoid residual urine exceeds 100 ml, whereas storage symptoms are most often managed by antimuscarinic medications. Intradetrusor injection of botulinum toxin type A is emerging as an effective treatment for managing refractory neurogenic detrusor overactivity. This review provides an overview of the clinical characteristics, diagnosis, and management of LUTD in patients with central and peripheral common neurological diseases.

Nerve-sparing radical hysterectomy in the precision surgery for cervical cancer

Precision cancer surgery is a system that integrates the accurate evaluation of tumor extension and aggressiveness, precise surgical maneuvers, prognosis evaluation, and prevention of the deterioration of quality of life (QoL). In this regard, nerve-sparing radical hysterectomy has a pivotal role in the personalized treatment of cervical cancer. Various types of radical hysterectomy can be combined with the nerve-sparing procedure. The extent of parametrium and vagina/paracolpium excision and the nerve-sparing procedure are tailored to the tumor status. Advanced magnetic resonance imaging technology will improve the assessment of the local tumor extension. Validated risk factors for perineural invasion might guide selecting treatment for cervical cancer. Type IV Kobayashi (modified Okabayashi) radical hysterectomy combined with the systematic nerve-sparing procedure aims to both maximize the therapeutic effect and minimize the QoL impairment. Regarding the technical aspect, the preservation of vesical nerve fibers is essential. Selective transection of uterine nerve fibers conserves the vesical nerve fibers as an essential piece of the pelvic nervous system comprising the hypogastric nerve, pelvic splanchnic nerves, and inferior hypogastric plexus. This method is anatomically and surgically valid for adequate removal of the parametrial and vagina/paracolpium tissues while preserving the total pelvic nervous system. Local recurrence after nerve-sparing surgery might occur due to perineural invasion or inadequate separation of pelvic nerves cutting through the wrong tissue plane between the pelvic nerves and parametrium/paracolpium. Postoperative management for long-term maintenance of bladder function is as critical as preserving the pelvic nerves.

Probabilistic, spinally-gated control of bladder pressure and autonomous micturition by Barrington's nucleus CRH neurons

Micturition requires precise control of bladder and urethral sphincter via parasympathetic, sympathetic and somatic motoneurons. This involves a spino-bulbospinal control circuit incorporating Barrington’s nucleus in the pons (Barr). Ponto-spinal glutamatergic neurons that express corticotrophin-releasing hormone (CRH) form one of the largest Barr cell populations. Barr^CRH neurons can generate bladder contractions, but it is unknown whether they act as a simple switch or provide a high-fidelity pre-parasympathetic motor drive and whether their activation can actually trigger voids. Combined opto- and chemo-genetic manipulations along with multisite extracellular recordings in urethane anaesthetised CRH^Cre mice show that Barr^CRH neurons provide a probabilistic drive that generates co-ordinated voids or non-voiding contractions depending on the phase of the micturition cycle. CRH itself provides negative feedback regulation of this process. These findings inform a new inferential model of autonomous micturition and emphasise the importance of the state of the spinal gating circuit in the generation of voiding.

A Novel Alternative in the Treatment of Detrusor Overactivity? In Vivo Activity of O-1602, the Newly Synthesized Agonist of GPR55 and GPR18 Cannabinoid Receptors

The aim of the research was to assess the impact of O-1602—novel GPR55 and GPR18 agonist—in the rat model of detrusor overactivity (DO). Additionally, its effect on the level of specific biomarkers was examined. To stimulate DO, 0.75% retinyl acetate (RA) was administered to female rats’ bladders. O-1602, at a single dose of 0.25 mg/kg, was injected intra-arterially during conscious cystometry. Furthermore, heart rate, blood pressure, and urine production were monitored for 24 h, and the impact of O-1602 on the levels of specific biomarkers was evaluated. An exposure of the urothelium to RA changed cystometric parameters and enhanced the biomarker levels. O-1602 did not affect any of the examined cystometric parameters or levels of biomarkers in control rats. However, the O-1602 injection into animals with RA-induced DO ameliorated the symptoms of DO and caused a reversal in the described changes in the concentration of CGRP, OCT₃, BDNF, and NGF to the levels observed in the control, while the values of ERK1/2 and VAChT were significantly lowered compared with the RA-induced DO group, but were still statistically higher than in the control. O-1602 can improve DO, and may serve as a promising novel substance for the pharmacotherapy of bladder diseases.

Electrical stimulation for neuroregeneration in urology: a new therapeutic paradigm

PURPOSE OF REVIEW

The present review highlights regenerative electrical stimulation (RES) as potential future treatment options for patients with nerve injuries leading to urological dysfunction, such as urinary incontinence, voiding dysfunction or erectile dysfunction. Additionally, it will highlight the mechanism of nerve injury and regeneration as well as similarities and differences between RES and current electrical stimulation treatments in urology, functional electrical stimulation (FES) and neuromodulation.

RECENT FINDINGS

It has been demonstrated that RES upregulates brain-derived neurotrophic factor (BDNF) and its receptor to facilitate neuroregeneration, facilitating accurate reinnervation of muscles by motoneurons. Further, RES upregulates growth factors in glial cells. Within the past 2 years, RES of the pudendal nerve upregulated BDNF in Onuf's nucleus, the cell bodies of motoneurons that course through the pudendal nerve and accelerated functional recovery in an animal model of stress urinary incontinence. Additionally, electrical stimulation of the vaginal tissue in an animal model of stress urinary incontinence accelerated functional recovery.

SUMMARY

RES has great potential but future research is needed to expand the potential beneficial effects of RES in the field of urology.

Exercise modulates neuronal activation in the micturition circuit of chronically stressed rats: A multidisciplinary approach to the study of urologic chronic pelvic pain syndrome (MAPP) research network study

BACKGROUND

Rats exposed to water avoidance stress (WAS) show increased urinary frequency, increased somatosensory nociceptive reflex responses, as well as altered brain responses to bladder distension, analogous to similar observations made in patients with urologic chronic pelvic pain syndrome (UCPPS). Exercise has been proposed as a potential treatment option for patients with chronic urinary frequency and urgency. We examined the effects of exercise on urinary voiding parameters and functional brain activation during bladder distension in rats exposed to WAS.

METHODS

Adult, female Wistar Kyoto rats were exposed to 10 days of WAS and thereafter randomized to either voluntary exercise for 3 weeks or sedentary groups. Voiding parameters were assessed at baseline, post-WAS, and weekly for 3 weeks. Thereafter, cerebral blood flow (CBF) mapping was performed during isotonic bladder distension (20 cm H2O) after intravenous bolus injection of [14C]-iodoantipyrine. Regional CBF was quantified in autoradiographs of brain slices and analyzed in 3-D reconstructed brains by statistical parametric mapping. Functional connectivity was examined between regions of the micturition circuit through interregional correlation analysis.

RESULTS

WAS exposure in sedentary animals (WAS/no-EX) increased voiding frequency and decreased urinary volumes per void. Exercise exposure in WAS animals (WAS/EX) resulted in a progressive decline in voiding frequency back to the baseline, as well as increased urinary volumes per void. Within the micturition circuit, WAS/EX compared to WAS/no-EX demonstrated a significantly lower rCBF response to passive bladder distension in Barrington's nucleus that is part of the spinobulbospinal voiding reflex, as well as in the periaqueductal gray (PAG) which modulates this reflex. Greater rCBF was noted in WAS/EX animals broadly across corticolimbic structures, including the cingulate, medial prefrontal cortex (prelimbic, infralimbic areas), insula, amygdala, and hypothalamus, which provide a 'top-down' decision point where micturition could be inhibited or triggered. WAS/EX showed a significantly greater positive brain functional connectivities compared to WAS/no-EX animals within regions of the extended reflex loop (PAG, Barrington's nucleus, intermediodorsal thalamic nucleus, pons), as well as within regions of the corticolimbic decision-making loop of the micturition circuit, with a strikingly negative correlation between these pathways. Urinary frequency was positively correlated with rCBF in the pons, and negatively correlated with rCBF in the cingulate cortex.

CONCLUSION

Our results suggest that chronic voluntary exercise may decrease urinary frequency at two points of control in the micturition circuit. During the urine storage phase, it may diminish the influence of the reflex micturition circuit itself, and/or it may increase corticolimbic control of voiding. Exercise may be an effective adjunct therapeutic intervention for modifying the urinary symptoms in patients with UCPPS.

Identification of a Sacral, Visceral Sensory Transcriptome in Embryonic and Adult Mice

Visceral sensory neurons encode distinct sensations from healthy organs and initiate pain states that are resistant to common analgesics. Transcriptome analysis is transforming our understanding of sensory neuron subtypes but has generally focused on somatic sensory neurons or the total population of neurons in which visceral neurons form the minority. Our aim was to define transcripts specifically expressed by sacral visceral sensory neurons, as a step towards understanding the unique biology of these neurons and potentially leading to identification of new analgesic targets for pelvic visceral pain. Our strategy was to identify genes differentially expressed between sacral dorsal root ganglia (DRG) that include somatic neurons and sacral visceral neurons, and adjacent lumbar DRG that comprise exclusively of somatic sensory neurons. This was performed in adult and E18.5 male and female mice. By developing a method to restrict analyses to nociceptive Trpv1 neurons, a larger group of genes were detected as differentially expressed between spinal levels. We identified many novel genes that had not previously been associated with pelvic visceral sensation or nociception. Limited sex differences were detected across the transcriptome of sensory ganglia, but more were revealed in sacral levels and especially in Trpv1 nociceptive neurons. These data will facilitate development of new tools to modify mature and developing sensory neurons and nociceptive pathways.

Exploratory analysis of the effect of mirabegron on urodynamic sensation parameters and urethral pressure variations

INTRODUCTION AND HYPOTHESIS

Urethral instability (URI) has in the past been defined by the International Continence Society (ICS), but was excluded from ICS terminology and definitions shortly after because of a lack of consensus about the clinical importance of this phenomenon. Recently, interest in URI and its possible role in overactive bladder (OAB) increased again. In the last decade, a beta 3 adrenoreceptor agonist (mirabegron) was approved for the treatment of OAB. The effect of mirabegron on urethral pressure during filling cystometry is unknown. The aim of this study was to assess the influence of mirabegron on urethral pressure variations during urodynamic investigation and the association of symptoms and voiding diary data before and during treatment.

METHODS

This prospective study included 51 consecutive adult female patients, referred with OAB. Patients were evaluated using a voiding diary, two validated questionnaires and two urodynamic investigations, one before and one after 6 weeks of treatment with mirabegron. URI was defined as an urethral pressure drop exceeding 30 cmH₂O during filling cystometry.

RESULTS

The prevalence of URI was 31% at initial urodynamic investigation, and 19% at second investigation. URI is more common than DO with 18% prevalence at initial evaluation. Treatment with mirabegron resulted in significant changes in symptoms and urodynamic sensory markers in patients with URI.

CONCLUSION

Urethral pressure variations are significantly reduced by treatment with mirabegron in patients with URI. URI seems to have a predictive value in treatment choices for OAB. Future research should elucidate this.

Nerve transfer for restoration of lower motor neuron-lesioned bladder and urethra function: establishment of a canine model and interim pilot study results

OBJECTIVE

Previous patient surveys have shown that patients with spinal cord or cauda equina injuries prioritize recovery of bladder function. The authors sought to determine if nerve transfer after long-term decentralization restores bladder and sphincter function in canines.

METHODS

Twenty-four female canines were included in this study. Transection of sacral roots and hypogastric nerves (S Dec) was performed in 6 animals, and 7 animals underwent this procedure with additional transection of the L7 dorsal roots (L7d+S Dec). Twelve months later, 3 L7d+S Dec animals underwent obturator-to-pelvic nerve and sciatic-to-pudendal nerve transfers (L7d+S Dec+Reinn). Eleven animals served as controls. Squat-and-void behaviors were tracked before and after decentralization, after reinnervation, and following awake bladder-filling procedures. Bladders were cystoscopically injected with Fluoro-Gold 3 weeks before euthanasia. Immediately before euthanasia, transferred nerves were stimulated to evaluate motor function. Dorsal root ganglia were assessed for retrogradely labeled neurons.

RESULTS

Transection of only sacral roots failed to reduce squat-and-void postures; L7 dorsal root transection was necessary for significant reduction. Three L7d+S Dec animals showing loss of squat-and-void postures post-decentralization were chosen for reinnervation and recovered these postures 4-6 months after reinnervation. Each showed obturator nerve stimulation-induced bladder contractions and sciatic nerve stimulation-induced anal sphincter contractions immediately prior to euthanasia. One showed sciatic nerve stimulation-induced external urethral sphincter contractions and voluntarily voided twice following nonanesthetized bladder filling. Reinnervation was confirmed by increased labeled cells in L2 and the L4-6 dorsal root ganglia (source of obturator nerve in canines) of L7d+S Dec+Reinn animals, compared with controls.

CONCLUSIONS

New neuronal pathways created by nerve transfer can restore bladder sensation and motor function in lower motor neuron-lesioned canines even 12 months after decentralization.

Contribution of Cav1.2 Ca2+ channels and store-operated Ca2+ entry to pig urethral smooth muscle contraction

Urethral smooth muscle (USM) generates tone to prevent urine leakage from the bladder during filling. USM tone has been thought to be a voltage-dependent process, relying on Ca²⁺ influx via voltage-dependent Ca²⁺ channels in USM cells, modulated by the activation of Ca²⁺-activated Cl^- channels encoded by Ano1. However, recent findings in the mouse have suggested that USM tone is voltage independent, relying on Ca²⁺ influx through Orai channels via store-operated Ca²⁺ entry (SOCE). We explored if this pathway also occurred in the pig using isometric tension recordings of USM tone. Pig USM strips generated myogenic tone, which was nearly abolished by the Ca_v1.2 channel antagonist nifedipine and the ATP-dependent K⁺ channel agonist pinacidil. Pig USM tone was reduced by the Orai channel blocker GSK-7975A. Electrical field stimulation (EFS) led to phentolamine-sensitive contractions of USM strips. Contractions of pig USM were also induced by phenylephrine. Phenylephrine-evoked and EFS-evoked contractions of pig USM were reduced by ~50-75% by nifedipine and ~30% by GSK-7975A. Inhibition of Ano1 channels had no effect on tone or EFS-evoked contractions of pig USM. In conclusion, unlike the mouse, pig USM exhibited voltage-dependent tone and agonist/EFS-evoked contractions. Whereas SOCE plays a role in generating tone and agonist/neural-evoked contractions in both species, this dominates in the mouse. Tone and agonist/EFS-evoked contractions of pig USM are the result of Ca²⁺ influx primarily through Ca_v1.2 channels, and no evidence was found supporting a role of Ano1 channels in modulating these mechanisms.

[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.

HCN as a Mediator of Urinary Homeostasis: Age-Associated Changes in Expression and Function in Adrenergic Detrusor Relaxation

The Hyperpolarization activated, cyclic nucleotide gated (HCN) channel is a candidate mediator of neuroendocrine influence over detrusor tonus during filling. In other tissues, HCN loss with aging is linked to declines in rhythmicity and function. We hypothesized that HCN has an age-sensitive expression profile and functional role in adrenergic bladder relaxation. HCN was examined in bladders from young (2-6 months) and old (18-24 months) C57BL/6 female mice, using qRT-PCR, RNAScope, and Western blots. Isometric tension studies were conducted using bladder strips from young wild-type (YWT), old wild-type (OWT), and young HCN1 knock-out (YKO) female mice to test the role HCN in effects of β-adrenergic stimulation. Hcn1 is the dominant HCN isoform RNA in the mouse bladder wall, and is diminished with age. Location of Hcn RNA within the mouse bladder wall is isoform-specific, with HCN1 limited to the detrusor layer. Passively-tensioned YWT bladder strips are relaxed by isoproterenol in the presence of HCN function, where OWT strips are relaxed only in the presence of HCN blockade. HCN has an age-specific expression and function in adrenergic detrusor relaxation in mouse bladder strips.

Study on neuropathological mechanisms of primary monosymptomatic nocturnal enuresis in children using cerebral resting-state functional magnetic resonance imaging

Primary monosymptomatic nocturnal enuresis (PMNE) is a heterogeneous disorder, which remains a difficult condition to manage due to lack of knowledge on the underlying pathophysiological mechanisms. Here we investigated the underlying neuropathological mechanisms of PMNE with functional MRI (fMRI), combining the amplitude of low frequency fluctuation (ALFF), regional homogeneity (ReHo), and seed-based functional connectivity (seed-based FC) analyses. Compared to the control group, PMNE group showed decreased ALFF value in the left medial orbital superior frontal gyrus (Frontal_Med_Orb_L), and increased ReHo value in the left superior occipital gyrus (Occipital_Sup_L). With left thalamus as the seed, PMNE group showed significantly decreased functional connectivity to the left medial superior frontal gyrus (Frontal_Sup_Medial_L). We conclude that these abnormal brain activities are probably important neuropathological mechanisms of PMNE in children. Furthermore, this study facilitated the understanding of underlying pathogenesis of PMNE and may provide an objective basis for the effective treatment.

Propriospinal Neurons of L3-L4 Segments Involved in Control of the Rat External Urethral Sphincter

Coordination of activity of external urethral sphincter (EUS) striated muscle and bladder (BL) smooth muscle is essential for efficient voiding. In this study we examined the morphological and electrophysiological properties of neurons in the L3/L4 spinal cord (SC) that are likely to have an important role in EUS-BL coordination in rats. EUS-related SC neurons were identified by retrograde transsynaptic tracing following injection of pseudorabies virus (PRV) co-expressing fluorescent markers into the EUS of P18-P20 male rats. Tracing revealed not only EUS motoneurons in L6/S1 but also interneurons in lamina X of the L6/S1 and L3/L4 SC. Physiological properties of fluorescently labeled neurons were assessed during whole-cell recordings in SC slices followed by reconstruction of biocytin-filled neurons. Reconstructions of neuronal processes from transverse or longitudinal slices showed that some L3/L4 neurons have axons projecting toward and into the ventro-medial funiculus (VMf) where axons extended caudally. Other neurons had axons projecting within laminae X and VII. Dendrites of L3/L4 neurons were distributed within laminae X and VII. The majority of L3/L4 neurons exhibited tonic firing in response to depolarizing currents. In transverse slices focal electrical stimulation (FES) in the VMf or in laminae X and VII elicited antidromic axonal spikes and/or excitatory synaptic responses in L3/L4 neurons; while in longitudinal slices FES elicited excitatory synaptic inputs from sites up to 400 μm along the central canal. Inhibitory inputs were rarely observed. These data suggest that L3/L4 EUS-related circuitry consists of at least two neuronal populations: segmental interneurons and propriospinal neurons projecting to L6/S1.

Remote Analgesic Effects Of Conventional Transcutaneous Electrical Nerve Stimulation: A Scientific And Clinical Review With A Focus On Chronic Pain

BACKGROUND

Transcutaneous electrical nerve stimulation (TENS) is a safe, noninvasive treatment for chronic pain that can be self-administered. Conventional TENS involves stimulation of peripheral sensory nerves at a strong, non-painful level. Following the original gate-control theory of pain, stimulation is typically near the target pain. As another option, remote stimulation may also be effective and offers potential advantages.

OBJECTIVE

This narrative review examines mechanisms underlying the remote analgesic effects of conventional TENS and appraises the clinical evidence.

METHODS

A literature search for English-language articles was performed on PubMed. Keywords included terms related to the location of TENS . Citations from primary references and textbooks were examined for additional articles.

RESULTS

Over 30 studies reported remote analgesic effects of conventional TENS. The evidence included studies using animal models of pain, experimental pain in humans, and clinical studies in subjects with chronic pain. Three types of remote analgesia were identified: at the contralateral homologous site, at sites distant from stimulation but innervated by overlapping spinal segments, and at unrelated extrasegmental sites.

CONCLUSION

There is scientific and clinical evidence that conventional TENS has remote analgesic effects. This may occur through modulation of pain processing at the level of the dorsal horn, in brainstem centers mediating descending inhibition, and within the pain matrix. A broadening of perspectives on how conventional TENS produces analgesia may encourage researchers, clinicians, and medical-device manufacturers to develop novel ways of using this safe, cost-effective neuromodulation technique for chronic pain.

Role of p38 MAP kinase signaling pathways in storage and voiding dysfunction in mice with spinal cord injury

AIM

To investigate the role of p38 MAP kinase in lower urinary tract dysfunction in mice with spinal cord injury (SCI).

METHODS

Cystometry and external urethral sphincter-electromyography were performed under an awake condition in 4-week SCI female mice. Two weeks after SCI, a catheter connected to an osmotic pump filled with a p38 mitogen-activated protein kinase (MAPK) inhibitor or artificial cerebrospinal fluid (CSF) was implanted into the intrathecal space of L6-S1 spinal cord for continuous intrathecal instillation at infusion rate of 0.51 μL/h for 2 weeks before the urodynamic study. L6 dorsal root ganglia were then removed from CSF and p38 MAPK inhibitor-treated SCI mice as well as from CSF-treated normal (spinal intact) mice to evaluate the levels of transient receptor potential cation channel subfamily V member 1 (TRPV1), tumor necrosis factor-α (TNF-α), and inducible nitric oxide synthase (iNOS) transcripts by real-time polymerase chain reaction.

RESULTS

In p38 MAPK inhibitor-treated SCI mice, nonvoiding contractions during bladder filling, bladder capacity, and post-void residual volume were significantly reduced while micturition pressure and voiding efficiency were significantly increased in comparison to these measurements in CSF-treated SCI mice. The expression of TRPV1, TNF-α, and iNOS messenger RNA was increased in SCI mice compared with expression in spinal intact mice and significantly decreased after p38 MAPK inhibitor treatment.

CONCLUSIONS

The p38 MAPK signaling pathway in bladder sensory neurons or in the spinal cord plays an important role in storage and voiding problems such as detrusor overactivity and inefficient voiding after SCI.

Recommendations for evaluation of bladder and bowel function in pre-clinical spinal cord injury research

Objective: In order to encourage the inclusion of bladder and bowel outcome measures in preclinical spinal cord injury (SCI) research, this paper identifies and categorizes 1) fundamental, 2) recommended, 3) supplemental and 4) exploratory sets of outcome measures for pre-clinical assessment of bladder and bowel function with broad applicability to animal models of SCI.Methods: Drawing upon the collective research experience of autonomic physiologists and informed in consultation with clinical experts, a critical assessment of currently available bladder and bowel outcome measures (histological, biochemical, in vivo functional, ex vivo physiological and electrophysiological tests) was made to identify the strengths, deficiencies and ease of inclusion for future studies of experimental SCI.Results: Based upon pre-established criteria generated by the Neurogenic Bladder and Bowel Working Group that included history of use in experimental settings, citations in the literature by multiple independent groups, ease of general use, reproducibility and sensitivity to change, three fundamental measures each for bladder and bowel assessments were identified. Briefly defined, these assessments centered upon tissue morphology, voiding efficiency/volume and smooth muscle-mediated pressure studies. Additional assessment measures were categorized as recommended, supplemental or exploratory based upon the balance between technical requirements and potential mechanistic insights to be gained by the study.Conclusion: Several fundamental assessments share reasonable levels of technical and material investment, including some that could assess bladder and bowel function non-invasively and simultaneously. Such measures used more inclusively across SCI studies would advance progress in this high priority area. When complemented with a few additional investigator-selected study-relevant supplemental measures, they are highly recommended for research programs investigating the efficacy of therapeutic interventions in preclinical animal models of SCI that have a bladder and/or bowel focus.

Expression and distribution of PIEZO1 in the mouse urinary tract

The proper function of the organs that make up the urinary tract (kidneys, ureters, bladder, and urethra) depends on their ability to sense and respond to mechanical forces, including shear stress and wall tension. However, we have limited understanding of the mechanosensors that function in these organs and the tissue sites in which these molecules are expressed. Possible candidates include stretch-activated PIEZO channels (PIEZO1 and PIEZO2), which have been implicated in mechanically regulated body functions including touch sensation, proprioception, lung inflation, and blood pressure regulation. Using reporter mice expressing a COOH-terminal fusion of Piezo1 with the sequence for the tandem-dimer Tomato gene, we found that PIEZO1 is expressed in the kidneys, ureters, bladder, and urethra as well as organs in close proximity, including the prostate, seminal vesicles and ducts, ejaculatory ducts, and the vagina. We further found that PIEZO1 expression is not limited to one cell type; it is observed in the endothelial and parietal cells of the renal corpuscle, the basolateral surfaces of many of the epithelial cells that line the urinary tract, the interstitial cells of the bladder and ureters, and populations of smooth and striated muscle cells. We propose that in the urinary tract, PIEZO1 likely functions as a mechanosensor that triggers responses to wall tension.

Intermittent restraint stress induces circadian misalignment in the mouse bladder, leading to nocturia

Intermittent stress disrupts the circadian rhythm in clock genes such as Per2 only in peripheral organs without any effect on the central circadian clock in the suprachiasmatic nucleus. Here, the effect of restraint stress (RS) on circadian bladder function was investigated based on urination behavior and gene expression rhythms. Furthermore, PF670462 (PF), a Per2 phosphorylation enzyme inhibitor, was administered to investigate the effects on circadian bladder re-alignment after RS. Two-hour RS during the light (sleep) phase was applied to mice (RS mice) for 5 days. The following parameters were then examined: urination behaviors; clock gene expression rhythms and urinary sensory-related molecules such as piezo type mechanosensitive ion channel component 1 (Piezo1), transient receptor potential cation channel subfamily V member 4 (TRPV4), and Connexin26 (Cx26) in the bladder mucosa; Per2 expression in the excised bladder of Per2^luciferase knock-in mice (Per2::luc); in vivo Per2 expression rhythms in the bladder of Per2::luc mice. Control mice did not show altered urination behavior in the light phase, whereas RS mice exhibited a higher voiding frequency and lower bladder capacity. In the bladder mucosa, RS mice also showed abrogated or misaligned Piezo1, TRPV4, Connexin26, and clock gene expression. The rhythmic expression of Per2 was also altered in RS mice both in excised- and in vivo bladder, compared with control mice. After PF administration, voiding frequency was reduced and bladder capacity was increased during the light phase in RS mice; the in vivo Per2 expression rhythm was also fully restored. Therefore, RS can alter circadian gene expression in the bladder during the light phase and might cause nocturia via changes in circadian bladder function due the dysregulation of clock genes. Amending the circadian rhythm therapeutically could be applied for nocturia.

Time-Dependent Changes of Urethral Function in Diabetes Mellitus: A Review

This article reviewed the current knowledge on time-course manifestation of diabetic urethral dysfunction (DUD), and explored an early intervention target to prevent the contribution of DUD to the progression of diabetes-induced impairment of the lower urinary tract (LUT). In the literature search through PubMed, key words used included “diabetes mellitus,” “diabetic urethral dysfunction,” and “diabetic urethropathy.” Polyuria and hyperglycemia induced by diabetes mellitus (DM) can cause the time-dependent changes in functional and morphological manifestations of DUD. In the early stage, it promotes urethral dysfunction characterized by increased urethral pressure during micturition. However, the detrusor muscle of the bladder tries to compensate for inducing complete voiding by increasing the duration and amplitude of bladder contractions. As the disease progresses, it can induce an impairment of coordinated micturition due to dyssynergic activity of external urethra sphincter, leading to detrusor-sphincter dyssynergia. The impairment of relaxation mechanisms of urethral smooth muscles (USMs) may additionally be attributable to decreased responsiveness to nitric oxide, as well as increased USM responsiveness to α₁-adrenergic receptor stimulation. In the late stage, diabetic neuropathy may play an important role in inducing LUT dysfunction, showing that the decompensation of the bladder and urethra, which can cause the decrease of voiding efficiency and the reduced thickness of the urothelium and the atrophy of striated muscle bundles, possibly leading to the vicious cycle of the LUT dysfunction. Further studies to increase our understandings of the functional and molecular mechanisms of DUD are warranted to explore potential targets for therapeutic intervention of DM-induced LUT dysfunction.

Adherence and effectiveness of a single instruction of pelvic floor exercises: a randomized clinical trial

INTRODUCTION AND HYPOTHESIS

In Brazil there are limited knowledge and education about preventative exercises for pelvic floor muscles (PFMs). We hypothesised that a single pelvic floor muscle exercise (PFME) session immediately postpartum would be effective in preventing urinary incontinence (UI) in a 3-month postpartum period with good adherence rates.

METHODS

Two hundred two women were approached for this randomised controlled trial and randomly assigned to two groups: the control group and experimental group. The intervention comprised a visual assessment of PFM contraction, a single PFME instruction session supervised by a physical therapist, and an educational approach through distribution of brochures about home-based PFME exercises (without supervision). Involuntary urinary loss and quality of life (QoL) were evaluated using the International Consultation on Incontinence Questionnaire Short Form (main outcome). Sociodemographic and clinical information was collected. Adherence and barriers were assessed via telephone/mobile phone surveys (secondary outcomes).

RESULTS

The adherence rate was 85.1%; only 37% of the women reported having some knowledge about PFME prior to participating in this study. The main barriers to PFME mentioned were forgetfulness (61.2%), lack of time (52.2%), and the need to take care of the baby (56.7%). One instruction session on postnatal PFME delivered in the immediate postpartum period was ineffective for improving urinary symptoms such as frequency of leakage (p = 0.821), amount of leakage (p = 0.746), and influence of leakage on QoL (p = 0.823). In addition, there was no difference in QoL 3 months post-partum (p = 0.872).

CONCLUSIONS

Although the proposed intervention did not prevent UI symptoms, the adherence rate to PFME was high.

Simultaneous Measurement of Neuronal Activity in the Pontine Micturition Center and Cystometry in Freely Moving Mice

Understanding the complex neural mechanisms controlling urinary bladder activity is an extremely important topic in both neuroscience and urology. Simultaneously recording of the bladder activity and neural activity in related brain regions will largely advance this field. However, such recording approach has long been restricted to anesthetized animals, whose bladder function and urodynamic properties are largely affected by anesthetics. In our recent report, we found that it is feasible to record bladder pressure (cystometry) and the related cortical neuron activity simultaneously in freely moving mice. Here, we aimed to demonstrate the use of this combined method in freely moving mice for recording the activity of the pontine micturition center (PMC), a more difficultly approachable small region deeply located in the brainstem and a more popularly studied hub for controlling bladder function. Interestingly, we found that the duration of urination events linearly correlated to the time course of neuronal activity in the PMC. We observed that the activities of PMC neurons highly correlated with spike-like increases in bladder pressure, reflecting bladder contractions. We also found that anesthesia evoked prominent changes in the dynamics of the Ca²⁺ signals in the PMC during the bladder contraction and even induced the dripping overflow incontinence due to suppression of the neural activity in the PMC. In addition, we described in details both the system for cystometry in freely moving mice and the protocols for how to perform this combined method. Therefore, this work provides a powerful approach that enables the simultaneous measurement of neuronal activity of the PMC or any other brain sites and bladder function in freely behaving mice. This approach offers a promising possibility to examine the neural mechanisms underlying neurogenic bladder dysfunction.

Traumatic Brain Injury-related voiding dysfunction in mice is caused by damage to rostral pathways, altering inputs to the reflex pathways

Brain degeneration, including that caused by traumatic brain injury (TBI) often leads to severe bladder dysfunction, including incontinence and lower urinary tract symptoms; with the causes remaining unknown. Male C57BL/6J mice underwent repetitive moderate brain injury (rmdTBI) or sham injury, then mice received either cis P-tau monoclonal antibody (cis mAb), which prevents brain degeneration in TBI mice, or control (IgG). Void spot assays revealed age-dependent incontinence in IgG controls 8 months after injury, while cis mAb treated or sham mice showed no dysfunction. No obvious bladder pathology occurred in any group. Urodynamic cystometry in conscious mice revealed overactive bladder, reduced maximal voiding pressures and incontinence in IgG control, but not sham or cis mAb treated mice. Hyperphosphorylated tau deposition and neural tangle-like pathology occurred in cortical and hippocampal regions only of IgG control mice accompanied with post-traumatic neuroinflammation and was not seen in midbrain and hindbrain regions associated with bladder filling and voiding reflex arcs. In this model of brain degeneration bladder dysfunction results from rostral, and not hindbrain damage, indicating that rostral brain inputs are required for normal bladder functioning. Detailed analysis of the functioning of neural circuits controlling bladder function in TBI should lead to insights into how brain degeneration leads to bladder dysfunction, as well as novel strategies to treat these disorders.

Motor cortical neuromodulation of pelvic floor muscle tone: Potential implications for the treatment of urologic conditions

AIMS

In the human brain, supplementary motor area (SMA) is involved in the control of pelvic floor muscles (PFMs). SMA dysfunction has been implicated in several disorders involving PFMs, including urinary incontinence and urologic pain. Here, we aimed to provide a proof-of-concept study to demonstrate the feasibility of modulating resting PFM activity (tone) as well as SMA activity with noninvasive stimulation of SMA.

METHODS

We studied six patients (3 women + 3 men) with Urologic Chronic Pelvic Pain Syndrome. Repetitive transcranial magnetic stimulation (rTMS) was applied to SMA immediately after voiding. We tested two rTMS protocols: high-frequency (HF-rTMS) which is generally excitatory, and low-frequency (LF-rTMS) which is generally inhibitory. PFM activity was measured during rTMS using electromyography. Brain activity was measured immediately before and after rTMS using functional magnetic resonance imaging.

RESULTS

The rTMS protocols had significantly different effects on resting activity in PFMs (P = 0.03): HF-rTMS decreased and LF-rTMS increased pelvic floor tone. SMA activity showed a clear trend ( P = 0.06) toward the expected differential changes: HF-rTMS increased and LF-rTMS decreased SMA activity.

CONCLUSIONS

We interpret the differential effects of rTMS at the brain and muscle level as novel support for an important inhibitory influence of SMA activity on pelvic floor tone after voiding. This preliminary study provides a framework for designing future studies to determine if neuromodulation of SMA could augment therapy for chronic urologic conditions.

Anti-Nogo-A Antibodies As a Potential Causal Therapy for Lower Urinary Tract Dysfunction after Spinal Cord Injury

Loss of bladder control is common after spinal cord injury (SCI) and no causal therapies are available. Here we investigated whether function-blocking antibodies against the nerve-fiber growth inhibitory protein Nogo-A applied to rats with severe SCI could prevent development of neurogenic lower urinary tract dysfunction. Bladder function of rats with SCI was repeatedly assessed by urodynamic examination in fully awake animals. Four weeks after SCI, detrusor sphincter dyssynergia had developed in all untreated or control antibody-infused animals. In contrast, 2 weeks of intrathecal anti-Nogo-A antibody treatment led to significantly reduced aberrant maximum detrusor pressure during voiding and a reduction of the abnormal EMG high-frequency activity in the external urethral sphincter. Anatomically, we found higher densities of fibers originating from the pontine micturition center in the lumbosacral gray matter in the anti-Nogo-A antibody-treated animals, as well as a reduced number of inhibitory interneurons in lamina X. These results suggest that anti-Nogo-A therapy could also have positive effects on bladder function clinically.SIGNIFICANCE STATEMENT After spinal cord injury, loss of bladder control is common. Detrusor sphincter dyssynergia is a potentially life-threatening consequence. Currently, only symptomatic treatment options are available. First causal treatment options are urgently needed in humans. In this work, we show that function-blocking antibodies against the nerve-fiber growth inhibitory protein Nogo-A applied to rats with severe spinal cord injury could prevent development of neurogenic lower urinary tract dysfunction, in particular detrusor sphincter dyssynergia. Anti-Nogo-A therapy has entered phase II clinical trial in humans and might therefore soon be the first causal treatment option for neurogenic lower urinary tract dysfunction.

Bladder overactivity and afferent hyperexcitability induced by prostate-to-bladder cross-sensitization in rats with prostatic inflammation

KEY POINTS

There is clinical evidence showing that prostatic inflammation contributes to overactive bladder symptoms in male patients; however, little is known about the underlying mechanisms In this study, we investigated the mechanism that prostatic inflammation causes detrusor overactivity by using a rat model of chemically induced prostatic inflammation. We observed a significant number of dorsal root ganglion neurons with dichotomized afferents innervating both prostate and bladder. We also found that prostatic inflammation induces bladder overactivity and urothelial NGF overexpression in the bladder, both dependent on activation of the pelvic nerve, as well as changes in ion channel expression and hyperexcitability of bladder afferent neurons. These results indicate that the prostate-to-bladder cross-sensitization through primary afferent pathways in the pelvic nerve, which contain dichotomized afferents, could be an important mechanism contributing to bladder overactivity and afferent hyperexcitability induced by prostatic inflammation.

ABSTRACT

Prostatic inflammation is reportedly an important factor inducing lower urinary tract symptoms (LUTS) including urinary frequency, urgency and incontinence in patients with benign prostatic hyperplasia (BPH). However, the underlying mechanisms inducing bladder dysfunction after prostatic inflammation are not well clarified. We therefore investigated the effects of prostatic inflammation on bladder activity and afferent function using a rat model of non-bacterial prostatic inflammation. We demonstrated that bladder overactivity, evident as decreased voided volume and shorter intercontraction intervals in cystometry, was observed in rats with prostatic inflammation versus controls. Tissue inflammation, evident as increased myeloperoxidase activity, and IL-1α, IL-1β, and IL-6 levels inside the prostate, but not in the bladder, following intraprostatic formalin injection induced an increase in NGF expression in the bladder urothelium, which depended on activation of the pelvic nerve. A significant proportion (18-19%) of dorsal root ganglion neurons were double labelled by dye tracers injected into either bladder or prostate. In rats with prostatic inflammation, TRPV1, TRPA1 and P2X2 increased, and Kv1.4, a potassium channel α-subunit that can form A-type potassium (K_A ) channels, decreased at mRNA levels in bladder afferent and double-labelled neurons vs. non-labelled neurons, and slow K_A current density decreased in association with hyperexcitability of these neurons. Collectively, non-bacterial inflammation localized in the prostate induces bladder overactivity and enhances bladder afferent function. Thus, prostate-to-bladder afferent cross-sensitization through primary afferents in the pelvic nerve, which contain dichotomized afferents, could underlie storage LUTS in symptomatic BPH with prostatic inflammation.

Sympathetic afferents in the hypogastric nerve facilitate nociceptive bladder activity in cats

This study in α-chloralose-anesthetized cats revealed a role of hypogastric nerve afferent axons in nociceptive bladder activity induced by bladder irritation using 0.25% acetic acid (AA). In cats with intact hypogastric and pelvic nerves, AA irritation significantly ( P < 0.05) reduced bladder capacity to 45.0 ± 5.7% of the control capacity measured during a saline cystometrogram (CMG). In cats with the hypogastric nerves transected bilaterally, AA irritation also significantly ( P < 0.05) reduced bladder capacity, but the change was significantly smaller (capacity reduced to 71.5 ± 10.6% of saline control, P < 0.05) than that in cats with an intact hypogastric nerve. However, application of hypogastric nerve stimulation (HGNS: 20 Hz, 0.2 ms pulse width) to the central end of the transected nerves at an intensity (16 V) strong enough to activate C-fiber afferent axons facilitated the effect of AA irritation and further ( P < 0.05) reduced bladder capacity to 48.4 ± 7.4% of the saline control. This facilitation by HGNS was effective only at selected frequencies (1, 20, and 30 Hz) when the stimulation intensity was above the threshold for activating C-fibers. Tramadol (an analgesic agent) at 3 mg/kg iv completely blocked the nociceptive bladder activity and eliminated the facilitation by HGNS. HGNS did not alter non-nociceptive bladder activity induced by saline distention of the bladder. These results indicate that sympathetic afferents in the hypogastric nerve play an important role in the facilitation of the nociceptive bladder activity induced by bladder irritation that activates the silent C-fibers in the pelvic nerve.

Nociceptin/Orphanin FQ and Urinary Bladder

Following identification as the endogenous ligand for the NOP receptor, nociceptin/orphanin FQ (N/OFQ) has been shown to control several biological functions including the micturition reflex. N/OFQ elicits a robust inhibitory effect on rat micturition by reducing the excitability of the afferent fibers. After intravesical administration N/OFQ increases urodynamic bladder capacity and volume threshold in overactive bladder patients but not in normal subjects. Moreover daily treatment with intravesical N/OFQ for 10 days significantly reduced urine leakage episodes. Different chemical modifications were combined into the N/OFQ sequence to generate Rec 0438 (aka UFP-112), a peptide NOP full agonist with high potency and selectivity and long-lasting duration of action. Rec 0438 mimicked the robust inhibitory effects of N/OFQ on rat micturition reflex; its action is solely due to NOP receptor stimulation, does not show tolerance liability after 2 weeks of treatment, and can be elicited by intravesical administration. Collectively the evidence summarized and discussed in this chapter strongly suggests that NOP agonists are promising innovative drugs to treat overactive bladder.

Neural Sensing of Organ Volume

Many internal organs change volume periodically. For example, the stomach accommodates ingested food and drink, the bladder stores urine, the heart fills with blood, and the lungs expand with every breath. Specialized peripheral sensory neurons function as mechanoreceptors that detect tissue stretch to infer changes in organ volume and then relay this information to the brain. Central neural circuits process this information and evoke perceptions (satiety, nausea), control physiology (breathing, heart rate), and impact behavior (feeding, micturition). Yet, basic questions remain about how neurons sense organ distension and whether common sensory motifs are involved across organs. Here, we review candidate mechanosensory receptors, cell types, and neural circuits, focusing on the stomach, bladder, and airways. Understanding mechanisms of organ stretch sensation may provide new ways to treat autonomic dysfunction.

Brain activation during the voiding phase of micturition in healthy adults: A meta-analysis of neuroimaging studies

Several studies have used a variety of neuroimaging techniques to measure brain activity during the voiding phase of micturition. However, there is a lack of consensus on which regions of the brain are activated during voiding. The aim of this meta-analysis is to identify the brain regions that are consistently activated during voiding in healthy adults across different studies. We searched the literature for neuroimaging studies that reported brain co-ordinates that were activated during voiding. We excluded studies that reported co-ordinates only for bladder filling, during pelvic floor contraction only, and studies that focused on abnormal bladder states such as the neurogenic bladder. We used the activation-likelihood estimation (ALE) approach to create a statistical map of the brain and identify the brain co-ordinates that were activated across different studies. We identified nine studies that reported brain activation during the task of voiding in 91 healthy subjects. Together, these studies reported 117 foci for ALE analysis. Our ALE map yielded six clusters of activation in the pons, cerebellum, insula, anterior cingulate cortex (ACC), thalamus, and the inferior frontal gyrus. Regions of the brain involved in executive control (frontal cortex), interoception (ACC, insula), motor control (cerebellum, thalamus), and brainstem (pons) are involved in micturition. This analysis provides insight into the supraspinal control of voiding in healthy adults and provides a framework to understand dysfunctional voiding. Clin. Anat., 2018. © 2018 Wiley Periodicals, Inc.

Involvement of TRPM4 in detrusor overactivity following spinal cord transection in mice

Transient receptor potential cation channel subfamily M member 4 (TRPM4) has been shown to play a key role in detrusor contractility under physiological conditions. In this study, we investigated the potential role of TRPM4 in detrusor overactivity following spinal cord transection (SCT) in mice. TRPM4 expression and function were evaluated in bladder tissue with or without the mucosa from spinal intact (SI) and SCT female mice (T8-T9 vertebra; 1-28 days post SCT) using PCR, western blot, immunohistochemistry, and muscle strip contractility techniques. TRPM4 was expressed in the urothelium (UT) and detrusor smooth muscle (DSM) and was upregulated after SCT. Expression levels peaked 3-7 days post SCT in both the UT and DSM. Pharmacological block of TRPM4 with the antagonist, 9-Phenanthrol (30 μM) greatly reduced spontaneous phasic activity that developed after SCT, regardless of the presence or absence of the mucosa. Detrusor overactivity following spinal cord injury leads to incontinence and/or renal impairment and represents a major health problem for which current treatments are not satisfactory. Augmented TRPM4 expression in the bladder after chronic SCT supports the hypothesis that TRPM4 channels play a role in DSM overactivity following SCT. Inhibition of TRPM4 may be beneficial for improving detrusor overactivity in SCI.