A better understanding of basic science may help our management of LUTS/LUTD in older persons with nocturnal polyuria and nocturia: ICI-RS 2024.

AIMS: To discuss the role of autocrine/paracrine signaling of urothelial arginine vasopressin (AVP) on mammalian bladder capacities and micturition thresholds, impact of distension on water/urea reabsorption from the bladder, review of the literature to better characterize the central/peripheral effects of AVP, desmopressin (dAVP) toxicity, and urine biomarkers of nocturia. METHODS: This review summarizes discussions during an International Consultation on Incontinence-Research Society 2024 think tank with respect to the role of urothelial AVP in aged individuals with nocturnal polyuria, impact of solute and water reabsorption by the bladder on uninterrupted sleep, central effects of AVP, pharmacological basis of dAVP toxicity, and biomarkers in nocturia/lower urinary tract dysfunction (LUTD) with neurological diseases. RESULTS: Consensus recognized AVP function and pathways in the central nervous system (CNS), pre-proAVP localized using immunohistochemistry in bladder sections from adult/aged noncancerous human punch biopsies and rodent bladder sections is likely to accelerate the systemic uptake of water and urea from the bladder of anesthetized mice instilled with 3H-water and 14C-urea. Mechanisms for charged and uncharged solutes and water transport across the bladder, mechanism of dAVP toxicity, and utility of urine biomarkers in those with neurological diseases/nocturia were determined from literature reviews. CONCLUSION: Pre-proAVP is present in human/rodent bladders and may be involved in water reabsorption from bladder that prevents the sensation of fullness for uninterrupted sleep in healthy adults. The mechanism of action of AVP in the CNS was discussed, as was electrolyte/water transport across the bladder, the basis for dAVP toxicity, and feasibility of urine biomarkers to identify nocturia/LUTD with neurological diseases.

Biological significance of MYC and CEBPD coamplification in urothelial carcinoma: Multilayered genomic, transcriptional and posttranscriptional positive feedback loops enhance oncogenic glycolysis.

BACKGROUND AND PURPOSE: The aim of this study is to decipher the underlying mechanisms of CCAAT/enhancer-binding protein delta (CEBPD)-enhanced glycolysis as well as the biological significance of CEBPD and MYC coamplification in urothelial carcinoma (UC). METHODS: In vitro analyses were conducted to examine the effects of altered CEBPD or MYC expression on UC cells. The in vivo effects of CEBPD overexpression in a high-glucose environment on tumour growth were investigated in xenografted induced diabetic severe combined immunodeficiency/beige mice. Data mining was used to cross-validate the associations between CEBPD and MYC copy number and transcriptional expression, quantitative reverse transcription-polymerase chain reaction, immunohistochemistry, chromogenic in situ hybridization, and in situ hybridization targeting microRNA were performed on 635 UC patient samples and xenograft samples. UC patient survival in relation to diabetes was validated by using the National Health Insurance Research Database. RESULTS: CEBPD and MYC coamplification (29.6%) occurred at a high frequency, MYC expression promoted chromosomal instability, facilitating CEBPD copy number gain and expression. CEBPD promoted glucose uptake and lactate production by upregulating SLC2A1 and HK2, leading to mitochondrial fission, increased extracellular acidification rate and decreased oxygen consumption rate to fuel cell growth. CEBPD upregulated HK2 expression through multiple regulation pathways including MYC stabilization, suppression of FBXW7 transactivation and MYC-independent transcriptional suppression of hsa-miR-429. Clinical and xenografted experiments confirmed the growth advantage of CEBPD in relation to glucose metabolic dysregulation and the significant correlations between the expression of these genes. CONCLUSIONS: We confirmed that CEBPD has an oncogenic role in UC by activating AKT signalling and initiating metabolic reprogramming from mitochondrial oxidative phosphorylation to glycolysis to satisfy glucose addiction. These novel CEBPD- and MYC-centric multilayered positive feedback loops enhance cancer growth that could complement theranostic approaches.

Functional roles for PIEZO1 and PIEZO2 in urothelial mechanotransduction and lower urinary tract interoception.

The mechanisms that link visceral mechanosensation to the perception of internal organ status (i.e., interoception) remain elusive. In response to bladder filling, the urothelium releases ATP, which is hypothesized to stimulate voiding function by communicating the degree of bladder fullness to subjacent tissues, including afferent nerve fibers. To determine if PIEZO channels function as mechanosensors in these events, we generated conditional urothelial Piezo1-, Piezo2-, and dual Piezo1/2-knockout (KO) mice. While functional PIEZO1 channels were expressed in all urothelial cell layers, Piezo1-KO mice had a limited phenotype. Piezo2 expression was limited to a small subset of superficial umbrella cells, yet male Piezo2-KO mice exhibited incontinence (i.e., leakage) when their voiding behavior was monitored during their active dark phase. Dual Piezo1/2-KO mice had the most affected phenotype, characterized by decreased urothelial responses to mechanical stimulation, diminished ATP release, bladder hypoactivity in anesthetized Piezo1/2-KO females but not males, and urinary incontinence in both male and female Piezo1/2-KO mice during their dark phase but not inactive light one. Our studies reveal that the urothelium functions in a sex- and circadian rhythm-dependent manner to link urothelial PIEZO1/2 channel-driven mechanotransduction to normal voiding function and behavior, and in the absence of these signals, bladder dysfunction ensues.

[Pathophysiology of overactive bladder]. / Physiopathologie du syndrome clinique d'hyperactivité vésicale.

INTRODUCTION: The pathophysiology knowledge of the overactive bladder syndrome has evolved considerably over the past 20 years. The objective of this work was, from a review of the literature, to synthesize current knowledge on the pathophysiology of the overactive bladder syndrome. METHOD: A systematic review based on Pubmed, Embase, Google Scholar, was conducted in February 2020 using the keywords "overactive bladder" and "pathophysiology". RESULTS: Four pathophysiological mechanisms involved in the overactive bladder syndrome development can be described. They include the detrusor muscle dysfunction, an urothelial or sub-urothelial origin, a neurological origin and a change in the urinary microbiome. At the same time, it should be noted that all of the pathophysiological mechanisms described above are favored by different clinical conditions such as aging, ischemia, metabolic syndrome, menopause and the dysfunction of other abdominopelvic systems. CONCLUSION: The pathophysiology of the overactive bladder syndrome is complex and includes several mechanisms most often associated.

Carcinoma urotelial del tracto urinario superior: a propósito de un caso y revisión de la literatura / Upper urinary tract urothelial carcinoma: case report and review of the literature

El carcinoma urotelial (CU) del tracto urinario superior es infrecuente y representa solo del 5%-10% de todos los CU. Estas neoplasias crecen a partir del urotelio de los cálices renales hasta el tercio distal del uréter. Se reporta el caso de un paciente masculino de 68 años de edad quien presenta enfermedad actual de 3 meses de evolución caracterizada por dolor lumbar izquierdo, tipo cólico, de leve a moderada intensidad, el cual atenúa parcialmente con el uso de AINES, asociado a hematuria visible total de predominio nocturno. El uroanálisis mostró hematuria macroscópica y la citología urinaria evidenció atipias sugerentes de carcinoma. La TAC abdomino-pélvica contrastada evidenció un defecto de llenado en relación al cáliz inferior de riñón izquierdo y plastrón ganglionar paraaórtico izquierdo. Se practicó nefroureterectomía radical izquierda evidenciando tumor de 3 x 3 x 1 cm en relación a pelvis renal extensiva a cáliz inferior invadiendo parénquima renal. El estudio histopatológico mostró un carcinoma urotelial papilar infiltrativo de alto grado con márgenes sin lesiones y ganglios linfáticos con metástasis. El paciente evoluciona satisfactoriamente durante el período postoperatorio y actualmente recibe terapia adyuvante. A pesar de ser una patología poco frecuente, puede presentarse y el urólogo debe estar en capacidad para poder enfrentarla(AU)

Upper urinary tract urothelial carcinoma (UC) is infrequent and represents only 5%-10% of all UCs. These neoplasms grow from the urothelium of renal calyces to the distal third of the ureter. A case of UC of the upper urinary tract is reported in a 68-year-old male patient with a 3-month history of left lumbar mild to moderate pain, which partially mitigates with the use of NSAIDs associated with visible total predominantly nocturnal hematuria. Macroscopic hematuria was evident and urinary cytology reported carcinoma suggestive atypias. Contrasted CT of abdomen and pelvis showed filling defect in relation to lower calyx of the left kidney and left para-aortic ganglion plastron. Radical left nephroureterectomy was performed showing a 3 x 3 x 1 cm tumor in relation to the renal pelvis extending to the lower cavity and invading renal parenchyma. Histopathology showed high grade infiltrative papillary CU with margins without lesions and lymph nodes with metastasis. Patient evolves satisfactorily in the postoperative period and is currently in adjuvant therapy. Although this pathology is rare, it can occur and the urologist must be able to face it(AU)

The urothelium, the urinary microbioma and men LUTS: a systematic review.

INTRODUCTION: The pathophysiology and management of male patients with lower urinary tract symptoms (LUTS) is still a matter of debate. In the past few years, the urothelium and the urinary microbiota represented important areas of research to improve the understanding and management of these patients. Aim of the present review was to summarize the available data on the urothelium and the microbiota related to male LUTS. EVIDENCE ACQUISITION: A National Center for Biotechnology Information (NCBI) PubMed search for relevant articles published between January 2000 and December 2019 was performed using the medical subjects heading "urothelium," "microbioma," "microbiota," "urobioma," "urobiota," "benign prostatic hyperplasia," "benign prostatic enlargement," "lower urinary tract symptoms," "lower urinary tract dysfunction," "men," "male," "overactive bladder," "receptors." Exclusion criteria included: animal studies and studies on muscarinic and adrenergic pathways. EVIDENCE SYNTHESIS: The urothelium has been recently evaluated in humans to evaluate new possible markers and pathways. New possible targets for the treatment of male LUTS include the neural growth factor, the cannabinoid, the vanilloid and the ATP pathways. However, studies in humans are still needed to elucidate the exact role of these pathways in the management of male patients with LUTS. The available evidence on the urinary microbioma in male is poor. Standing to the available, urinary microbioma is evident in healthy urine in males. Moreover, the urinary microbioma varies depending on the method of collection, sexually transmitted disease status, inflammation and urinary symptoms. A possible role of probiotics in the management of LUTS in women has been proposed and may have a role in male patients as well. CONCLUSIONS: The urothelium and the urinary microbiota are still poorly studied in men with LUTS. Most of the evidence and the hypothesis on the relationship between urothelium/urinary microbiota and LUTS comes from animal/in-vitro evidence while clinical trials are lacking. These pathways seem interesting even in LUTS pathogenesis in men but their possible role as a new therapeutic target is still an open debate.

Additive effects of intravenous and intravesical application of vibegron, a ß3-adrenoceptor agonist, on bladder function in rats with bladder overactivity.

To examine the effects of intravenous and intravesical application of vibegron, a new ß3-adrenoceptor (ß3-AR) agonist, on bladder function in rats with oxotremorine methiodide (oxo-M: a nonselective muscarinic receptor agonist)-induced bladder overactivity. Cystometry was performed in conscious female rats with intravesical instillation of oxo-M (200 µM). In oxo-M-treated rats, vehicle or vibegron (1 and 10 mg/kg) was cumulatively applied intravenously at 30-min intervals. In other groups of rats, oxo-M + vehicle or oxo-M + vibegron (10, 100 µM, and 1 mM) was cumulatively instilled intravesically at 60-min intervals followed by intravenous application of vibegron (10 mg/kg). Expression of ß3-ARs in the bladder was also evaluated using immunohistochemical staining. Intravenous application of vibegron (10 mg/kg) significantly increased bladder capacity (1.3 times) and decreased baseline, threshold, and maximal voiding pressure compared with vehicle. Next, intravesical application of vibegron (1 mM) significantly increased threshold pressure and bladder capacity (1.2 times) compared with vehicle. Combined treatments of intravesical (1 mM) and intravenous (10 mg/kg) application of vibegron induced a significantly larger degree of increases in bladder capacity (1.4 times) compared with vehicle. In addition, ß3-ARs were expressed throughout the rat bladder, mainly in the urothelium. These results suggest that vibegron excreted in urine as an unchanged compound can induce the additive inhibitory effects on bladder overactivity possibly through urothelial ß3-AR activation, which inhibits the afferent limb of micturition reflex rather than the efferent function as evidenced by the increases in threshold pressure and bladder capacity without affecting bladder contractile function after intravesical vibegron application.

Therapeutic effects of Choreito, a traditional Japanese (Kampo) medicine, on detrusor overactivity induced by acetic acid in rats.

Choreito (CRT), a traditional Japanese (Kampo) medicine, is widely used for the treatment of overactive bladder (OAB) and other lower urinary tract symptoms in Japan. This study aimed to identify the effects and therapeutic mechanism of CRT on the improvement of detrusor overactivity (DO) using an experimental rat model. Forty-five female Sprague-Dawley rats were equally divided into three groups: intravesical saline instillation with normal food (normal group), intravesical acetic acid (AA) instillation with normal food (AA group), and intravesical AA instillation with CRT (AA with CRT group). To induce a decrease in bladder capacity, instillation of 0.2% AA was used based on prior studies. Cystometric investigation was employed to clarify the effects of AA and CRT. Microcirculation was performed using a laser blood flowmeter, and the localization of hypoxia-inducible factor 1α (HIF1α) was assessed by immunohistochemistry. The bladder capacities of the normal, AA, and AA with CRT groups were 1.2 ± 0.3 mL, 0.4 ± 0.1 mL, and 0.8 ± 0.1 mL, respectively. CRT significantly attenuated AA irritation of the urinary bladder and exerted protective effects on basal pressure, micturition pressure, micturition interval, and micturition volume. Furthermore, CRT could prevent the excess blood flow and edematous change under the urothelium induced by intravesical AA instillation. No obvious changes in immunohistochemical HIF1α staining were observed among the groups. CRT attenuated DO induced by intravesical AA instillation in a rat experimental model. CRT might impart therapeutic effects on OAB via the mitigation of urothelial damage and regulation of excess blood flow.

ICI-RS 2019 nocturia think tank: How can experimental science guide us in understanding the pathophysiology of nocturia?

INTRODUCTION: The following is a report on the proceedings of the 2019 International Consultation on Incontinence-Research Society nocturia think tank (NTT). OBJECTIVES: The objectives of the 2019 NTT were as follows: (a) to evaluate the role of urothelium in the pathophysiology of nocturia; (b) to determine whether nocturia is a circadian disorder; (c) to discuss the role of melatonin in nocturia; (d) to consider ambulatory urodynamic monitoring in evaluating patients with nocturia; (e) to explore studies of water handling in human compartments utilizing heavy water; and (f) to explore whether basic science is the key to understanding the treatment options for diminished bladder capacity in patients with nocturia. METHODS: A compendium of discussions of the role of experimental science in understanding the pathophysiology of nocturia is described herein. RESULTS AND CONCLUSIONS: Translational science will play an increasing role in understanding the pathophysiology of nocturia, which may result in improved treatment strategies.

Crosstalk between tubular epithelial cells and glomerular endothelial cells in diabetic kidney disease.

In recent years, although the development of clinical therapy for diabetic kidney disease (DKD) has made great progress, the progression of DKD still cannot be controlled. Therefore, further study of the pathogenesis of DKD and improvements in DKD treatment are crucial for prognosis. Traditional studies have shown that podocyte injury plays an important role in this process. Recently, it has been found that glomerulotubular balance and tubuloglomerular feedback (TGF) may be involved in the progression of DKD. Glomerulotubular balance is the specific gravity absorption of the glomerular ultrafiltrate by the proximal tubules, which absorbs only 65% to 70% of the ultrafiltrate. This ensures that the urine volume will not change much regardless of whether the glomerular filtration rate (GFR) increases or decreases. TGF is one of the significant mechanisms of renal blood flow and self-regulation of GFR, but how they participate in the development of DKD in the pathological state and the specific mechanism is not clear. Injury to tubular epithelial cells (TECs) is the key link in DKD. Additionally, injury to glomerular endothelial cells (GECs) plays a key role in the early occurrence and development of DKD. However, TECs and GECs are close to each other in anatomical position and can crosstalk with each other, which may affect the development of DKD. Therefore, the purpose of this review was to summarize the current knowledge on the crosstalk between TECs and GECs in the pathogenesis of DKD and to highlight specific clinical and potential therapeutic strategies.

Pathophysiological Mechanisms of Nocturia and Nocturnal Polyuria: The Contribution of Cellular Function, the Urinary Bladder Urothelium, and Circadian Rhythm.

Alterations to arginine vasopressin (AVP) secretion, the urinary bladder urothelium (UT) and other components of the bladder, and the water homeostasis biosystem may be relevant to the pathophysiology of nocturia and nocturnal polyuria (NP). AVP is the primary hormone involved in water homeostasis. Disruption to the physiological release of AVP or its target effects may relate to several urinary disturbances. Circadian dysregulation and the effects of aging, for example, the development of oxidative stress and mitochondrial dysfunction, may play a role in nocturia voiding symptoms. The urinary bladder UT not only acts as a highly efficient barrier that is maintained during the filling and voiding of the urinary bladder, but is also capable of sensory and transducer function through a network of functional receptors and ion channels that enable reciprocal communication between UT cells and neighboring elements of the bladder mucosa and wall. Functional components of the UT (eg, claudins and receptors or ion channels) play important roles in AVP-mediated water homeostasis. These components and functions involved in water homeostasis, as well as kidney function, may be affected by the aging process, including age-related mitochondrial dysfunction. The characteristics of NP are discussed and the association between NP and circadian rhythm is examined in light of reports that suggest that nocturia should be considered as a type of circadian dysfunction. Many possible pathologic mechanisms that underlie nocturia and NP have been identified. Future studies may provide further insight into pathophysiology with the hope of identifying new treatment modalities.

Nicotine-induced hypoxia in rat urothelium deteriorates bladder storage functions.

AIMS: To measure the effects of nicotine on lower urinary tract symptoms (LUTS), bladder blood flow, and the urothelial markers hypoxia-inducible factor 1α (HIF1α), uroplakin III (UPIII), and aquaporin 3 (AQP3). METHODS: Ten-week-old female Sprague Dawley rats were subcutaneously injected with 2 mg/kg nicotine (n = 17) or vehicle (control, n = 18) twice daily for 13 days. Some nicotine-treated rats (n = 10) were injected daily with 1 mg/kg tadalafil for the last 6 days of nicotine treatment. One day before cystometry, the bladders of some nicotine-treated and control rats were instilled with 0.08% acetic acid. Urinary frequency and volume were measured 1 day after treatment. Blood flow in the bladder neck was measured, and the urothelia were immunochemically assayed for HIF1α, UPIII, and AQP3. RESULTS: Following acetic acid treatment, both voiding interval and micturition volume of the nicotine-treated rats were significantly lower than controls. Nicotine-treated rats had lower blood flow than controls, and the urothelial expression of HIF1α was higher than controls. Simultaneously, the expressions of UPIII and AQP3 were decreased. Tadalafil treatment increased bladder blood flow, and nicotine-treated rats had increased voiding interval and micturition volume. Further, the expression of HIF1α decreased, and both UPIII and AQP3 levels increased. CONCLUSIONS: Nicotine-treated rats stimulated by intravesicular acetic acid instillation exhibited deterioration of bladder storage functions. Changes in tissue markers in the nicotine-treated rats were consistent with hypoxia and loss of urothelial function. Restoration of blood flow reversed the nicotine effects. Nicotine may induce LUTS through reduced bladder blood flow and urothelial hypoxia.

[Mechanisms of kidney damage].

The results of recent studies on the mechanisms of kidney damage are presented in the review of literature. The role of the immune system in the occurrence, development and outcome of damage to the epithelium of the renal tubules, as well as molecular, genetic and metabolic changes which determine the extent and consequences of renal trauma are described in details. The mechanisms of restoration of the renal parenchyma and the development of fibrosis following the cessation of injury are given.

Urinary K+ promotes irritative voiding symptoms and pain in the face of urothelial barrier dysfunction.

The internal surface of the bladder is lined by the urothelium, a stratified epithelium that forms an impermeable barrier to water and urine constituents. Abnormalities in the urothelial barrier have been described in certain forms of cystitis and were hypothesized to contribute to irritative voiding symptoms and pain by allowing the permeation of urinary K+ into suburothelial tissues, which then alters afferent signaling and smooth muscle function. Here, we examined the mechanisms underlying organ hyperactivity and pain in a model of cystitis caused by adenoviral-mediated expression of claudin-2 (Cldn2), a tight junction protein that forms paracellular pores and increases urothelial permeability. We found that in the presence of a leaky urothelium, intravesical K+ sensitizes bladder afferents and enhances their response to distension. Notably, dietary K+ restriction, a maneuver that reduces urinary K+, prevented the development of pelvic allodynia and inflammation seen in rats expressing Cldn2. Most importantly, intravesical K+ causes and is required to maintain bladder hyperactivity in rats with increased urothelial permeability. Our study demonstrates that in the face of a leaky urothelium, urinary K+ is the main determinant of afferent hyperexcitability, organ hyperactivity and pain. These findings support the notion that voiding symptoms and pain seen in forms of cystitis that coexist with urothelial barrier dysfunction could be alleviated by cutting urinary K+ levels.

Transperitoneal radical nephroureterectomy is associated with worse disease progression than retroperitoneal radical nephroureterectomy in patients with upper urinary tract urothelial carcinoma.

This study aimed to compare the oncologic outcomes between retroperitoneal radical nephroureterectomy (rRNU) and transperitoneal radical nephroureterectomy (tRNU) for the treatment of patients with upper urinary tract urothelial carcinoma (UTUC). Medical records of 743 eligible patients who underwent rRNU or tRNU between 1995 and 2015 were reviewed retrospectively. Progression-free survival (PFS), cancer-specific survival (CSS), and overall survival (OS) were compared according to the surgical approach using the Kaplan-Meier method. Predictors of PFS, CSS, and OS were analyzed with a multivariable Cox regression model. Overall, 620 (83.4%) and 123 (16.6%) patients were treated with rRNU and tRNU, respectively. Five-year CSS and OS rates were equivalent between rRNU and tRNU groups, but 5-year PFS was lower in the tRNU group than the rRNU group (P = 0.005). When patients were stratified by pathological T stage, PFS was significantly different between the two groups in favor of the rRNU group for both organ-confined disease (pTis/pTa/pT1/T2) (P = 0.022) and locally advanced disease (pT3/pT4) (P = 0.039). However, no significant differences in CSS or OS was observed when comparing the two surgical types in patients with organ-confined disease (P = 0.336 and P = 0.851) or patients with locally advanced disease (P = 0.499 and P = 0.278). tRNU was a significant predictor of PFS (hazard ratio = 1.54; P = 0.023), but not CSS or OS. Our findings indicate that the rRNU approach resulted in better PFS than the tRNU approach in patients with UTUC.

A Comprehensive Review of Overactive Bladder Pathophysiology: On the Way to Tailored Treatment.

CONTEXT: Current literature suggests that several pathophysiological factors and mechanisms might be responsible for the nonspecific symptom complex of overactive bladder (OAB). OBJECTIVE: To provide a comprehensive analysis of the potential pathophysiology underlying detrusor overactivity (DO) and OAB. EVIDENCE ACQUISITION: A PubMed-based literature search was conducted in April 2018, to identify randomised controlled trials, prospective and retrospective series, animal model studies, and reviews. EVIDENCE SYNTHESIS: OAB is a nonspecific storage symptom complex with poorly defined pathophysiology. OAB was historically thought to be caused by DO, which was either "myogenic" (urgency initiated from autonomous contraction of the detrusor muscle) or "neurogenic" (urgency signalled from the central nervous system, which initiates a detrusor contraction). Patients with OAB are often found to not have objective evidence of DO on urodynamic studies; therefore, alternative mechanisms for the development of OAB have been postulated. Increasing evidence on the role of urothelium/suburothelium and bladder afferent signalling arose in the early 2000s, emphasising an afferent "urotheliogenic" hypothesis, namely, that urgency is initiated from the urothelium/suburothelium. The urethra has also recently been regarded as a possible afferent origin of OAB-the "urethrogenic" hypothesis. Several other pathophysiological factors have been implicated, including metabolic syndrome, affective disorders, sex hormone deficiency, urinary microbiota, gastrointestinal functional disorders, and subclinical autonomic nervous system dysfunctions. These various possible mechanisms should be considered as contributing to diagnostic and treatment algorithms. CONCLUSIONS: There is a temptation to label OAB as "idiopathic" without obvious causation, given the poorly understood nature of its pathophysiology. OAB should be seen as a complex, multifactorial symptom syndrome, resulting from multiple potential pathophysiological mechanisms. Identification of the underlying causes on an individual basis may lead to the definition of OAB phenotypes, paving the way for personalised medical care. PATIENT SUMMARY: Overactive bladder (OAB) is a storage symptom syndrome with multiple possible causes. Identification of the mechanisms causing a patient to experience OAB symptoms may help tailor treatment to individual patients and improve outcomes.

Single onabotulinumtoxinA 200U dose improved clinical symptoms but not urothelial dysfunction in neurogenic detrusor overactivity due to spinal cord injury.

OBJECTIVE: To evaluate the changes in urothelial dysfunction protein expressions in bladder after onabotulinumtoxin injection and correlate that with clinical outcomes in spinal cord injury (SCI) patients. METHODS: Twenty-six patients with neurogenic detrusor overactivity (NDO) and urinary incontinence due to suprasacral SCI were treated with onabotulinumtoxinA 200U detrusor injection. Urodynamic studies and bladder biopsies were obtained at baseline, 3, and 6 months after treatment. Biopsy tissues were investigated for E-cadherin, zonula occludens-1 (ZO-1), mast cell activity, and urothelial cell apoptosis, sensory protein expression including purinergic receptor P2X3, endothelial NOS, inducible NOS, ß3-adrenoceptors, and muscarinic receptors M2 and M3. Differences in functional protein expression between controls and SCI patients and between successful and failed treatment groups were analyzed. RESULTS: SCI patients had significantly lower E-cadherin, higher mast cell activity, increased apoptosis, decreased M3 and eNOS expressions than the controls at baseline. Of the 26 patients, 17 (65%) showed improvement in bladder capacity by >50% at 3 months; however, improvement declined by 6 months after treatment. The urothelial expression of E-cadherin and ZO-1 increased at 3 months but had declined at 6 months. The urothelial sensory protein expression did not change significantly after treatment. M3 receptor density was significantly decreased in SCI patients at baseline and patients with treatment success 3 months after injection (p = 0.01). CONCLUSION: A single injection of onabotulinumtoxinA 200U improved clinical symptoms but did not significantly alter urothelial sensory protein expression. The results imply that a single 200U onabotulinumtoxinA dose might not be adequate for urothelial dysfunction in NDO. IRB: TCGH 098-53.

Stress-induced autonomic dysregulation of mitochondrial function in the rat urothelium.

AIM: Chronic stress exacerbates the symptoms of most pain disorders including interstitial cystitis/bladder pain syndrome (IC/BPS). Abnormalities in urothelial cells (UTC) occur in this debilitating bladder condition. The sequence of events that might link stress (presumably through increased sympathetic nervous system-SNS activity) to urothelial dysfunction are unknown. Since autonomic dysregulation, mitochondrial dysfunction, and oxidative stress all occur in chronic pain, we investigated whether chronic psychological stress initiated a cascade linking these three dysfunctions. METHODS: Adult female Wistar Kyoto rats were exposed to 10 days of water avoidance stress (WAS). Bladders were then harvested for Western blot and single cell imaging in UTC cultures. RESULTS: UTC from WAS rats exhibited depolarized mitochondria membrane potential (Ψm ∼30% more depolarized compared to control), activated AMPK and altered UT mitochondria bioenergetics. Expression of the fusion protein mitofusion-2 (MFN-2) was upregulated in the mucosa, suggesting mitochondrial structural changes consistent with altered cellular metabolism. Intracellular calcium levels were elevated in cultured WAS UTC, consistent with impaired cellular function. Stimulation of cultured UTC with alpha-adrenergic (α-AR) receptor agonists increased reactive oxidative species (ROS) production, suggesting a direct action of SNS activity on UTC. Treatment of rats with guanethidine to block SNS activity prevented most of WAS-induced changes. CONCLUSIONS: Chronic stress results in persistent sympathetically mediated effects that alter UTC mitochondrial function. This may impact the urothelial barrier and signaling, which contributes to bladder dysfunction and pain. This is the first demonstration, to our knowledge, of a potential autonomic mechanism directly linking stress to mitochondrial dysfunction.

Polyploid Superficial Cells that Maintain the Urothelial Barrier Are Produced via Incomplete Cytokinesis and Endoreplication.

The urothelium is an epithelia barrier lined by a luminal layer of binucleated, octoploid, superficial cells. Superficial cells are critical for production and transport of uroplakins, a family of proteins that assemble into a waterproof crystalline plaque that helps protect against infection and toxic substances. Adult urothelium is nearly quiescent, but rapidly regenerates in response to injury. Yet the mechanism by which binucleated, polyploid, superficial cells are produced remains unclear. Here, we show that superficial cells are likely to be derived from a population of binucleated intermediate cells, which are produced from mononucleated intermediate cells via incomplete cytokinesis. We show that binucleated intermediate and superficial cells increase DNA content via endoreplication, passing through S phase without entering mitosis. The urothelium can be permanently damaged by repetitive or chronic injury or disease. Identification of the mechanism by which superficial cells are produced may be important for developing strategies for urothelial repair.

What is the exact working mechanism of botulinum toxin A and sacral nerve stimulation in the treatment of overactive bladder/detrusor overactivity? ICI-RS 2017.

AIMS: Botulinum toxin A (BTX-A) and sacral nerve stimulation (SNS) are established treatments for overactive bladder (OAB) and are standard of care in refractory cases in international guidelines. Despite long term use over decades their "exact" working mechanisms are not entirely clear. At the ICI-RS meeting in Bristol in 2017 a think tank was convened to address the question. METHODS: The think tank conducted a literature review and an expert consensus meeting focusing on current mechanisms and what could be learned from clinical experience and objective urodynamic data. RESULTS: BTX-A results suggests effects on both filling and voiding parts of the micturition cycle. The salient data in this regard is presented as well as additional studies related to the urothelium and evidence for central effects. Urodynamics have consistently shown increases in bladder capacity, compliance, and reductions in detrusor pressures during filling, however post void residuals also increase in a dose-dependent fashion. During SNS activation of somatic afferents inhibits bladder sensory pathways and reflex bladder hyperactivity. Evidence in cats suggest the inhibition of bladder activity occurs primarily in the CNS by inhibition of the ascending or descending pathways of the spinobulbospinal micturition reflex. Urodynamics have suggested improvement in bladder capacity and reduction in detrusor pressures during filling with little observed effects on voiding parameters. CONCLUSIONS: The working mechanism of BTX-A and SNS is complex. The exact mechanisms are still unknown, although considerable progress has been made in our understanding. Further research proposals are suggested to help further elucidate these mechanisms.