Discussion: Potential future pharmacologic approaches

The Ameliorating Effect of Exogenous Melatonin on Urinary Bladder Function in Hyperosmolar Bladder Overactivity and its Influence on the Autonomic Nervous System Activity

This study was designed to investigate the effects of melatonin on the bladder hyperactivity in hyperosmolar-induced overactive bladder (OAB) rats. Additionally, the influence of melatonin on the autonomic nervous system (ANS) using heart rate variability (HRV) analysis was assessed. 40 rats were divided into four groups: I – control (n=12), II – rats with hyperosmolar OAB (n=6), III – rats with melatonin pretreatment and hyperosmolar OAB (n=6) and IV – control with melatonin pretreatment (n=6). In group III and IV melatonin in dose of 100 mg/kg was given. HRV measurements in 10 rats, as follow: control (n=2), control after melatonin treatment (n=2), rats with hyperosmolar OAB without (n=3), and after (n=3) melatonin treatment were conducted. This study demonstrates marked influence of melatonin on urinary bladder activity in hyperosmolar-induced OAB rats. These rats showed significantly reduced the detrusor motor overactivity resulting in the improvement of cystometric parameters after melatonin treatment when compared to the control, as follow: a significant increase of intercontraction interval (70 %) and functional bladder capacity (67 %), as well as a decrease of the basal pressure, detrusor overactivity index and motility index of 96 %, 439 % and 40 %, respectively. ANS activity analysis revealed sympathetic overactivity in OAB rats, and parasympathetic superiority in melatonin treated OAB rats. Melatonin treatment in rats with hyperosmolar OAB (group III) caused significant increase of nuHF parameter (from 51.00 ± 25.29 to 76.97 ± 17.43), as well as a decrease of nuLF parameter (from 49.01 ± 25.26 to 23.03 ± 17.43) and LF/HF ratio (from 1.280 ± 0.980 to 0.350 ± 0.330). In conclusion, melatonin suppresses hyperosmolar OAB, and modulates ANS activity by inhibition of the sympathetic drive. Therefore, melatonin may become a useful agent for OAB management.

Pathophysiology of overactive bladder

Overactive bladder (OAB) is a common disorder that negatively affects the quality of life of our patients and carries a large socioeconomic burden. According to the International Continence Society, it is characterized as urinary urgency, with or without urge incontinence, usually, with frequency and nocturia in the absence of causative infection. The pathophysiology of this disease entity varies between neurogenic, myogenic, or idiopathic factors. This paper provides a review of the contemporary theories behind the pathophysiology of OAB.

Hyperosmolarity alters micturition: a comparison of urinary bladder motor activity in hyperosmolar and cyclophosphamide-induced models of overactive bladder

Hyperosmolar factors induce the neurogenic inflammatory response, leading to bladder overactivity (OAB). The aim of the study was to compare the bladder motor activity in a hyperosmolar and acute cyclophosphamide (CYP)-induced model of OAB. Furthermore, we set our sights on defining the most physiological model of OAB in experimental practice. Forty-two female rats were divided randomly into 5 groups. All animals underwent cystometry with the usage of isotonic saline or saline of increasing concentration. Acute chemical cystitis was induced by CYP to elicit OAB. The following cystometric parameters were analyzed: basal pressure, threshold pressure, micturition voiding pressure, intercontraction interval, compliance, functional bladder capacity, motility index, and detrusor overactivity index. CYP and hypertonic saline solutions induced OAB. Having been compared with CYP OAB, none of the rats infused with hypertonic solution exhibited macroscopic signs of bladder inflammation. The comparison of CYP and hyperosmolar models of OAB revealed that the greatest similarity existed between the 2080 mOsm/L OAB model and the acute CYP-induced model. We postulate that the 2080 mOsm/L model of OAB can be established as being a less invasive and more physiological model when compared with the CYP-induced OAB model. Additionally, it may also be a more reliable experimental tool for evaluating novel therapeutics for OAB as compared with CYP-induced models.

Pelvic organ prolapse quantification in women referred with overactive bladder

INTRODUCTION AND HYPOTHESIS

A study was carried out to investigate the relationship of anterior vaginal wall descent or prolapse to overactive bladder and its potential mechanisms, advancing the management of overactive bladder (OAB).

METHODS

Two hundred twenty-six consecutive women with OAB symptoms were prospectively studied using OAB questionnaire (OAB-q) and pelvic organ prolapse quantification (POP-Q). According to POP-Q staging, they were divided into three groups: stages 0, I, and II. For statistical analysis, a one-way ANOVA was used to test for significant differences with Student-Newman-Keuls post hoc analysis for continuous variables (OAB-q symptom severity, health-related quality of life total scores, and age) and chi-squared test for discrete variable (number of menopausal women).

RESULTS

Twenty-two women (9.73%) did not show any prolapse on examination; 204 (90.26%) had anterior vaginal wall descent or prolapse. The outcome statistics denoted that the difference in OAB-q scores among three groups has statistical significance (P < 0.05). Anterior vaginal wall descent or prolapse may have associations with OAB.

CONCLUSIONS

Anterior vaginal wall descent or prolapse may have associations with OAB and is directly correlated to OAB severity.