Simulated vaginal delivery causes transients vaginal smooth muscle hypersensitivity and urethral sphincter dysfunction.

BACKGROUND: Although pelvic floor dysfunction (PFD) has a multifactorial etiology, pregnancy and childbirth are considered crucial events predisposing to urinary incontinence as well as pelvic organ prolapse, which are highly prevalent. Rats are the most frequently used animal model and pudendal nerve crush (PNC) and vaginal distension (VD) are often used to mimic vaginal delivery. OBJECTIVE: To document the time course of events after simulated vaginal delivery (SVD) on the urethral sphincter and the vaginal smooth muscle layer. MATERIALS AND METHODS: Virgin female Sprague-Dawley rats were subjected to SVD (PNC + VD) or sham surgery and evaluated at 7, 14, 21, and 42 days after the injury. Urethral function was determined in vivo by microultrasound during cystometry and vaginal smooth muscle layer was harvested for in vitro pharmacologic investigation by isometric tension recording. Furthermore, vaginal and urethral samples were investigated by immunohistochemistry and real-time quantitative polymerase chain reaction. RESULTS: Microultrasound showed no bursting of the urethral sphincter in the SVD group at 7 days with a functional recovery starting at 14 days, and normal bursting at 21 and 42 days. Vaginal smooth muscle showed higher sensitivity to carbachol at 14 and 21 days after injury; however, at 42 days, its sensitivity decreased when compared with sham. CONCLUSION: SVD induces urethral dysfunction and a shift in vaginal smooth muscle contractile responses to carbachol.

Ectopic leiomyoma as a late complication of laparoscopic hysterectomy with power morcellation: a case report and review of the literature.

Introduction: Electromechanical power morcellation is a widely used technique to extract uterine fibroids during laparoscopic hysterectomy. Although the complication rate of morcellators is low, ectopic leiomyoma can appear several years after their use.Patients and methods: We present a case of an ectopic leiomyoma and a literature review of power morcellation-induced complications and ectopic leiomyoma.Results: A 49-year-old female presented with epigastric pain 12 years after laparoscopic subtotal hysterectomy with morcellation of the specimen. Radiological examinations revealed an epigastric mass of 45 mm that was laparoscopically removed. Histological examination confirmed the diagnosis of an ectopic leiomyoma. Complications of power morcellation are rarely reported and include perioperative injuries to bowel, vascular and urinary tract, spreading of ectopic leiomyoma and occult malignancy.Conclusions: Ectopic leiomyoma are a late and rare complication of a laparoscopic hysterectomy with power morcellation of the uterus.

Functional and molecular characterisation of the bilateral pelvic nerve crush injury rat model for neurogenic detrusor underactivity.

OBJECTIVES: To create a rat model for neurogenic detrusor underactivity (DU) by bilateral pelvic nerve crush injury (BPNI) and to study temporal changes in detrusor contractility and morphology. MATERIALS AND METHODS: Male Sprague-Dawley rats were subjected to BPNI or sham surgery and evaluated at 1, 3 and 9 weeks after surgery. Bladder function was determined in vivo by awake cystometry, micturition pattern analysis, and 24-h urine collection. Bladders were harvested for in vitro pharmacological investigation by isometric tension recording. Bladders and major pelvic ganglia were investigated by quantitative reverse transcription-polymerase chain reaction and histochemistry. RESULTS: Overflow incontinence was observed at 1 week after BPNI. At 3 and 9 weeks after BPNI, rats showed a bladder phenotype characteristic for DU with increased post-void residual urine volumes, reduced voiding efficiencies, and lower maximum pressures. In isolated bladder strips, contractile responses to KCl, carbachol, and α,ß-methylene adenosine 5'-triphosphate (α,ß-mATP) were preserved. On the other hand, neural-induced contractility was reduced after BPNI, in line with reduced expression of protein gene product 9.5 and choline acetyltransferase in the major pelvic ganglion at 1 week after BPNI. The bladder-to-body weight ratio and detrusor thickness increased after BPNI, indicating detrusor hypertrophy to compensate for the reduced neural input. CONCLUSIONS: BPNI induces a rat model for neurogenic DU. In this model, the detrusor maintains its contractility but denervation of the detrusor was observed.

Characterization of voiding function and structural bladder changes in a rat model of neurogenic underactive bladder disease.

OBJECTIVES: To create an animal model for neurogenic underactive bladder disease (UAB) and identify markers to describe secondary myogenic changes in the bladder wall. MATERIALS AND METHODS: Male rats underwent either bilateral pelvic nerve injury or sham surgery. Four weeks after surgery functional evaluation was performed and tissue was harvested. Functional evaluation consisted of analysis of voiding pattern, 24-h urine collection in a metabolic cage, in vivo cystometry and in-vitro contractile function assessment. PCR and immunohistochemical localization of different smooth muscle cell and extracellular matrix markers was performed on bladder strips. RESULTS: After pelvic nerve injury, dry bladder weight increased and voiding contractions were absent, resulting in overflow incontinence. In-vitro contractile response to carbachol was decreased. This was paired with an upregulation of synthetic smooth muscle cell (SMC) markers mRNA expression such as retinol binding protein 1 (RBP1), myosin 10 (MYH10) and osteopontin (OPN), and a downregulation of contractile SMC marker smoothelin (SMTL). The SMTL/OPN mRNA ratio was 50 times higher in sham bladders compared to PNI bladders. CONCLUSIONS: The loss of in-vivo and in-vitro contractile function following pelvic nerve transection is characterized by a switch from a contractile to synthetic SMC phenotype, which is best characterized by the ratio SMTL/OPN mRNA expression. Modulating this phenotypical switch is a potential target for the development of UAB therapy. We suggest for the first time a set of markers that may be useful to evaluate therapeutic strategies on improvements in bladder wall structure.

Intravesical Activation of the Cation Channel TRPV4 Improves Bladder Function in a Rat Model for Detrusor Underactivity.

BACKGROUND: Improvement of bladder emptying by modulating afferent nerve activity is an attractive therapeutic strategy for detrusor underactivity. Transient receptor potential vanilloid 4 (TRPV4) is a sensory ion channel in urothelial cells that contribute to the detection of bladder filling. OBJECTIVE: To investigate the potential benefit of intravesical TRPV4 agonists in a pelvic nerve injury rat model for detrusor underactivity. DESIGN, SETTING, AND PARTICIPANTS: Female wild-type and Trpv4 knockout rats underwent sham surgery or bilateral pelvic nerve injury (bPNI). Four weeks later, rats underwent cystometry with infusion of the TRPV4 agonist GSK1016790A. Bladders were harvested for in vitro pharmacological studies, quantitative reverse polymerase chain reaction and immunohistochemistry. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Data are expressed as median ± interquartile range. Statistical comparisons were made using the Mann-Witney U test and Wilcoxon signed rank test as appropriate. RESULTS AND LIMITATIONS: Rats with bPNI showed a phenotype characteristic of detrusor underactivity with lower-amplitude voiding contractions, decreased voiding frequency, and increased postvoid residual. Intravesical application of GSK1016790A increased voiding frequency and reduced postvoid residual in wild-type, but not Trpv4-/-, rats. In isolated bladder strips, GSK1016790A did not induce relevant contractions, indicating that the observed improvements in bladder function are the result of increased afferent signalling through TRPV4 activation, rather than a local effect on the detrusor. The altered urinary phenotype of Trpv4-/- mice was not apparent in the Trpv4-/- rat model, suggesting species-related functional variations. Our results are limited to the preclinical setting in rodents. CONCLUSIONS: Intravesical activation of TRPV4 improves bladder dysfunction after bPNI by increasing afferent signalling. PATIENT SUMMARY: We demonstrate that the sensory protein transient receptor potential vanilloid 4 (TRPV4) can be targeted to improve bladder function in animals that have iatrogenic injury to the nerves innervating the bladder. Further research is required to determine whether these results can be translated to patients with an underactive bladder.

Addressing challenges in underactive bladder: recommendations and insights from the Congress on Underactive Bladder (CURE-UAB).

Underactive bladder (UAB) is an expanding troublesome health issue, exerting a major influence on the health and independence of older people with a disproportionally low level of attention received. The 2nd International Congress on Underactive Bladder (CURE-UAB 2) convened in Denver, CO on December 3 and 4, 2015, and comprised of top clinicians, scientists, and other stakeholders to address the challenges in UAB. A series of workshops aimed to define UAB and its phenotype, define detrusor underactivity (DU) and create a subtyping of DU, evaluate existing animal models for DU, and lastly to establish research priorities for UAB.

Adipose-derived Stem Cells Counteract Urethral Stricture Formation in Rats.

BACKGROUND: A medical treatment for urethral stricture (US) is not yet available. OBJECTIVE: To evaluate if local injection of human adipose tissue-derived stem cells (hADSC) prevents urethral fibrosis in a rat model of US. DESIGN, SETTING, AND PARTICIPANTS: Male rats were divided into three groups: sham, US, and hADSC (n=12 each). Sham rats received a vehicle injection in the urethral wall. US and hADSCs were incised and injected with the fibrosis-inducer transforming growth factor-ß1 in the urethral wall. INTERVENTION: One day later, hADSCs were injected in the urethral wall of hADSC rats whereas sham and US rats were injected with the vehicle. After 4 wk, the rats underwent cystometries and tissues were then harvested for functional and molecular analyses. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Cystometry, microultrasound, histochemistry, organ bath studies, reverse transcription polymerase chain reaction, and western blot. RESULTS AND LIMITATIONS: US rats exhibited 49-51% shorter micturition intervals, 35-51% smaller micturition volumes and bladder capacity, 33-62% higher threshold pressures and flow pressures, and 35-37% lower bladder filling compliance compared with hADSC-treated rats and sham rats (p<0.05). By ultrasound, US rats had hyperechogenic and thick urethral walls with narrowed lumen compared with sham rats, whereas hADSC rats displayed less extensive urethral changes. Isolated detrusor from US rats exhibited 34-55% smaller contractions than detrusor from sham rats (p<0.05). Corresponding values were 11-35% for isolated detrusors from hADSC rats. Collagen and elastin protein expression were increased in the penile urethras of US rats compared with sham and hADSC groups (p<0.05). Endothelial and inducible nitric oxide synthase expressions were higher (p<0.05) in the hADSC group. Compared with US rats, hADSC rats demonstrated decreased expression of several fibrosis-related genes. Administration of hADSCs was performed at an early stage of US development, which we consider a limitation of the study. CONCLUSIONS: Local injection of hADSCs prevents stricture formation and urodynamic complications in a new rat model for US. PATIENT SUMMARY: Stem cell therapy is effective for preventing urethral stricture in an experimental setting.