Enhancement of rat bladder contraction by artificial sweeteners via increased extracellular Ca2+ influx

Sweet taste receptors play roles in artificial sweetener-induced enhanced urine output in mice

Sweet taste receptors found in oral and extra oral tissues play important roles in the regulation of many physiological functions. Studies have shown that urine volume increases during the lifetime exposure to artificial sweeteners. However, the detailed molecular mechanism and the general effects of different artificial sweeteners exposure on urine volume remain unclear. In this study, we investigated the relationship between urinary excretion and the sweet taste receptor expression in mice after three artificial sweeteners exposure in a higher or lower concentration via animal behavioral studies, western blotting, and real-time quantitative PCR experiment in rodent model. Our results showed that high dose of acesulfame potassium and saccharin can significantly enhance the urine output and there was a positive correlation between K+ and urination volume. The acesulfame potassium administration assay of T1R3 knockout mice showed that artificial sweeteners may affect the urine output directly through the sweet taste signaling pathway. The expression of T1R3 encoding gene can be up-regulated specifically in bladder but not in kidney or other organs we tested. Through our study, the sweet taste receptors, distributing in many tissues as bladder, were indicated to function in the enhanced urine output. Different effects of long-term exposure to the three artificial sweeteners were shown and acesulfame potassium increased urine output even at a very low concentration.

Nutritional Considerations for Bladder Storage Conditions in Adult Females

BACKGROUND

Clinical guidelines developed by urologic, urogynecologic, and gynecologic associations around the globe include recommendations on nutrition-related lifestyle and behavioral change for bladder storage conditions. This study identified and compared clinical guidelines on three urological conditions (interstitial cystitis/bladder pain syndrome (IC/BPS), overactive bladder, and stress urinary incontinence) affecting adult women.

METHODS

A three-step process was employed to identify the guidelines. Next, a quality assessment of the guidelines was conducted employing the Appraisal of Guidelines Research and Evaluation (AGREE II) International tool. (3) Results: Twenty-two clinical guidelines, prepared by seventeen groups spanning four continents, met the inclusion criteria. The AGREE II analyses revealed that most of the guideline development processes complied with best practices. The most extensive nutrition recommendations were for women with IC/BPS. Dietary manipulation for the other two storage LUTS primarily focused on the restriction or limitation of specific beverages and/or optimal fluid intake. (4) Conclusion: Clinical guidelines for IC/BPS, overactive bladder, and stress urinary incontinence include nutrition recommendations; however, the extent of dietary manipulation varied by condition. The need to ensure that clinicians are informing patients of the limitations of the evidence supporting those recommendations emerged. Furthermore, given the need to treat nutrition-related comorbid conditions as a strategy to help mitigate these three urological disorders, the value of referral to a dietitian for medical nutrition therapy is apparent.

Artificially sweetened beverages and urinary incontinence-a secondary analysis of the Women's Health Initiative Observational Study

OBJECTIVE

The aim of this study was to determine if higher artificially sweetened beverage intake is associated with higher prevalence of urinary incontinence symptoms.

METHODS

We conducted a secondary analysis of data from the Women's Health Initiative Observational Study. Our analytic cohort included 80,388 women. Participants who answered questions about beverage consumption and urinary incontinence symptoms at a 3-year follow-up visit were included. Demographic characteristics were compared between three groups of beverage consumers: never to less than one serving per week, one to six servings per week, and greater than or equal to one serving per day. Multivariable logistic regression models were constructed to estimate odds and type of urinary incontinence and adjust for potential confounders.

RESULTS

Most participants (64%) were rare consumers of artificially sweetened beverages, with 13% ( n = 10,494) consuming greater than or equal to 1 serving per day. The unadjusted odds of reporting urinary incontinence were 10% to 12% higher in women consuming one to six servings per week (odds ratio [OR], 1.10; 95% CI, 1.06-1.14) or greater than or equal to one serving per day (OR, 1.12; 95% CI, 1.07-1.18) versus never to less than one serving per week. In multivariable analyses, women consuming greater than or equal to one serving per day (ref: never to <1 serving/wk) had 10% higher odds of reporting mixed urinary incontinence (OR, 1.10; 95% CI, 1.02-1.19). There were no significant differences for stress or urgency urinary incontinence symptoms between groups.

CONCLUSIONS

When compared to never to less than one serving per week, women consuming greater than or equal to one serving per day of artificially sweetened beverages had 10% greater odds of reporting mixed urinary incontinence after adjustments. Amount of artificially sweetened beverage consumption was not associated with stress or urgency urinary incontinence symptoms.

Compliance to Individualized Recommendations Based on an Evidence-Based Algorithm for Behavioral Management of Lower Urinary Tract Symptoms

PURPOSE

The aim of this study was to evaluate patient compliance to individualized recommendations for self-management of fluid intake, bladder irritants, and timing of fluid consumption.

DESIGN

Single-group, before-after pilot study.

SUBJECTS AND SETTING

The sample comprised 22 patients (17 male and 5 females, mean age 62 years, age range 27-84 years). The study setting was the uroflow clinic at Southmead Hospital, Bristol, UK, a tertiary level referral hospital for complex evaluation and treatment of urological patients.

METHODS

Patients were given a bladder diary to complete after 2 weeks, which was compared with the bladder diary they had originally brought to clinic, to see whether the advice was followed. The bladder diary used required the patient to document the times and volumes of urination over a period of 3 days, magnitude of urinary urgency felt at the time, along with fluid intake timing, amount, and type of beverage. The study was not designed to measure changes in symptoms, but observed changes recorded in the bladder diaries are reported.

RESULTS

All 6 of the 22 participants who were advised to increase the volume of fluid intake complied, with an increased average intake of a mean of 520 mL (range 100-1450 mL). Similarly, one participant advised to reduce fluid intake decreased their fluid intake by 1800 mL per day. Thirteen out of 16 patients (81%) who were advised to remove caffeine, alcohol, or artificial sweeteners from their diet complied, indicated by no bladder irritant being recorded on their bladder diary. Nine out of 12 patients (75%) advised to reduce fluid intake in the evenings complied, decreased fluid intake after 6 PM by an average of 240 mL (range 100-550 mL less).

CONCLUSIONS

A majority of participants given fluid intake advice that is specific to their symptoms and lifestyle complied with recommendations. Simple guidance could usefully be given to patients before they are referred to specialist urological care or undergo urodynamic testing.

Urinary Urgency in Working Women: What Factors Are Associated with Urinary Urgency Progression?

BACKGROUND

Urinary urgency is the primary symptom of overactive bladder (OAB). This study aimed to identify targets for effective intervention to delay progression of urinary urgency.

MATERIAL AND METHODS

Secondary analyses of data from a study conducted with female employees of a large academic medical center were conducted. Women were ≥18 years and nonpregnant at the time of the survey. An online questionnaire obtained demographic information, presence of lower urinary tract symptoms, and toileting behaviors. Bivariate analyses and multivariate logistic regression were applied to explore factors related to different stages of urinary urgency.

RESULTS

Four stages of urinary urgency were constructed: (1) Stage 1: no urinary symptoms (n = 20), (2) Stage 2: continent but urinary urgency reported (n = 19), (3) Stage 3: nonsevere urgency urinary incontinence (UUI) (incontinent but leakage ≤1/day, n = 74); and (4) Stage 4: severe UUI (leakage ≥1/day, n = 26). In multivariate analyses, older women were more likely to be in Stage 3 than in Stage 2 (aOR 1.053, 95% CI 1.012-1.096). Women who lost urine with defecation were more likely to be in Stage 4 than Stage 3 (aOR 3.828, 95% CI 1.921-7.629). Women who habitually strained to empty the bladder faster were more likely to be in Stage 4 than in Stage 3 (aOR 6.588, 95% CI 1.317-32.971).

CONCLUSIONS

Losing urine with defecation and making the bladder empty faster by pushing down should be explored as intervention targets to prevent women from progressing from Stage 3 to Stage 4.

Quality-of-Life Outcomes Following Surface Electromyography Biofeedback as an Adjunct to Pelvic Floor Muscle Training for Urinary Incontinence: A Case Report

Background

A non-invasive treatment for urinary incontinence (UI) is surface electromyography (sEMG) biofeedback with pelvic floor muscle (PFM) training. A lack of consensus and evidence exists on the Quality of Life (QoL) outcomes following sEMG biofeedback using surface electrodes at the perineum compared to the more invasive intravaginal probe. This case report examines QoL using sEMG biofeedback at the perineum with PFM training for UI.

Study Design

Single subject case report.

Case Description

The patient was a 61-year-old woman diagnosed with UI. Her chief complaints were nocturia, urine leakage with urgency, and urine leakage with sneezing and coughing. Physical therapy (PT) treatment focused on behavioral modification, PFM strengthening with and without sEMG biofeedback, and therapeutic exercises with PFM contractions.

Outcomes

At four weeks from baseline, the patient's PFM strength increased from 2/5 to 4/5 based on the Modified Laycock Scale. Her PFM endurance contraction improved from two seconds to ten seconds. The International Continence Impact Questionnaire - Urinary Incontinence Short Form (ICIQ-UI SF) score decreased from 6 to 0, the Incontinence Impact Questionnaire - Short Form (IIQ-7) score decreased from 14.3 to 0, and the 3 Incontinence Questions (3IQ) responses did not change.

Discussion

The outcomes from this case report demonstrate a brief course of PT treatment consisting of perineal sEMG biofeedback in conjunction with PFM training demonstrated clinically meaningful improvements in incontinence-related QoL, in addition to improvements in motor function in a woman with mixed UI and nocturia.

Lifestyle interventions for the treatment of urinary incontinence in adults

BACKGROUND

Low cost, non-invasive alterations in lifestyle are frequently recommended by healthcare professionals or those presenting with incontinence. However, such recommendations are rarely based on good evidence.

OBJECTIVES

The objective of the review was to determine the effectiveness of specific lifestyle interventions (i.e. weight loss; dietary changes; fluid intake; reduction in caffeinated, carbonated and alcoholic drinks; avoidance of constipation; stopping smoking; and physical activity) in the management of adult urinary incontinence.

SEARCH METHODS

We searched the Cochrane Incontinence Group Specialised Register, which contains trials identified from the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and MEDLINE in process, and handsearching of journals and conference proceedings (searched 3 July 2013), and the reference lists of relevant articles. We incorporated the results of these searches fully in the review. We undertook an updated search of the Specialised Register, which now includes searches of ClinicalTrials.gov and WHO ICTRP, on 27 October 2014; potentially eligible studies from this search are currently awaiting classification.

SELECTION CRITERIA

Randomised and quasi-randomised studies of community-based lifestyle interventions compared with no treatment, other conservative therapies, or pharmacological interventions for the treatment of urinary incontinence in adults.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. We collected information on adverse effects from the trials. Data were combined in a meta-analysis when appropriate. We assessed the quality of the evidence using the GRADE approach.

MAIN RESULTS

We included 11 trials in the review, involving a total of 5974 participants.Four trials involving 4701 women compared weight loss programmes with a control intervention. Low quality evidence from one trial suggested that more women following weight loss programmes reported improvement in symptoms of incontinence at six months (163/214 (76%) versus 49/90 (54%), risk ratio (RR) 1.40, 95% confidence interval (CI) 1.14 to 1.71), and this effect was sustained at 18 months (N = 291, 75% versus 62%, RR not estimable, reported P value 0.02). No data were available for self-reported cure and quality of life. One of the weight loss trials involving 1296 women reported very low quality evidence for a reduction in weekly urinary incontinence a mean of 2.8 years after following a lifestyle weight loss intervention that had been compared with a pharmacological weight loss intervention.Three trials involving 181 women and 11 men compared change in fluid intake with no change. Limited, very low quality evidence suggested that symptom-specific quality of life scores improved when fluid intake was reduced, although some people reported headaches, constipation or thirst. A further three trials involving 160 women and nine men compared reduction in caffeinated drinks with no change, and one trial involving 42 women compared a soy-rich diet with soy-free diet. However, it was not possible to reach any conclusions about the effects of these changes, due to methodological limitations, that resulted in very low quality evidence.Adverse effects appeared relatively uncommon for all interventions studied.All included studies had a high or unclear risk of bias across all bias parameters, but most notably for allocation concealment. The main factors for our downgrading of the evidence were risk of bias, indirect evidence (less than 12 months of follow-up; and not all participants having confirmed urinary incontinence at baseline in some studies), and imprecise results with wide confidence intervals.Other interventions such as reduction in consumption of sweetened fizzy or diet drinks; reduction in alcohol consumption; avoiding constipation; smoking cessation; restricting strenuous physical forces; or reducing high levels of, or increasing low levels of, physical activity, could not be assessed in this review, as no evidence from randomized controlled trials or quasi-randomised trials was available.

AUTHORS' CONCLUSIONS

Evidence for the effect of weight loss on urinary incontinence is building and should be a research priority. Generally, there was insufficient evidence to inform practice reliably about whether lifestyle interventions are helpful in the treatment of urinary incontinence.

Purinergic signalling in the urinary tract in health and disease

Purinergic signalling is involved in a number of physiological and pathophysiological activities in the lower urinary tract. In the bladder of laboratory animals there is parasympathetic excitatory cotransmission with the purinergic and cholinergic components being approximately equal, acting via P2X1 and muscarinic receptors, respectively. Purinergic mechanosensory transduction occurs where ATP, released from urothelial cells during distension of bladder and ureter, acts on P2X3 and P2X2/3 receptors on suburothelial sensory nerves to initiate the voiding reflex, via low threshold fibres, and nociception, via high threshold fibres. In human bladder the purinergic component of parasympathetic cotransmission is less than 3 %, but in pathological conditions, such as interstitial cystitis, obstructed and neuropathic bladder, the purinergic component is increased to 40 %. Other pathological conditions of the bladder have been shown to involve purinoceptor-mediated activities, including multiple sclerosis, ischaemia, diabetes, cancer and bacterial infections. In the ureter, P2X7 receptors have been implicated in inflammation and fibrosis. Purinergic therapeutic strategies are being explored that hopefully will be developed and bring benefit and relief to many patients with urinary tract disorders.

Intake of caffeinated, carbonated, or citrus beverage types and development of lower urinary tract symptoms in men and women

Evidence to substantiate recommendations for restriction of caffeinated or acidic beverages as self-management for lower urinary tract symptoms (LUTS) is limited. We examined longitudinal and acute associations between beverage intake and LUTS in the Boston Area Community Health (BACH) cohort (n = 4,144) between 2002 and 2010. Multivariable models tested associations between baseline intakes and progression of LUTS at 5-year follow-up, between follow-up intakes and International Prostate Symptom Scores at follow-up, and between 5-year intake changes and LUTS progression. Greater coffee or total caffeine intake at baseline increased the odds of LUTS progression in men (coffee: >2 cups/day vs. none, odds ratio = 2.09, 95% confidence interval: 1.29, 3.40, P-trend = 0.01; caffeine: P-trend < 0.001), particularly storage symptoms. Women who increased coffee intake by at least 2 servings/day during follow-up (compared with categories of decreased or unchanged intakes) had 64% higher odds of progression of urgency (P = 0.003). Women with recently increased soda intake, particularly caffeinated diet soda, had higher symptom scores, urgency, and LUTS progression. Citrus juice intake was associated with 50% lower odds of LUTS progression in men (P = 0.02). Findings support recommendations to limit caffeinated beverage intake for LUTS, and in men, they suggest benefits of citrus juice consumption. Further clinical research is warranted, particularly of the precise role of sodas containing artificial sweeteners in bladder sensations and urological function.

Expression and distribution of the sweet taste receptor isoforms T1R2 and T1R3 in human and rat bladders

PURPOSE

Artificial sweeteners augment bladder contraction. We hypothesized that artificial sweeteners activate sweet taste receptors in the bladder. Thus, we investigated the expression of sweet taste receptors in human and rat bladders.

MATERIALS AND METHODS

Sections of human and rat bladders were cut from paraffin blocks and stained by immunohistochemistry for the expression of T1R2/3 sweet taste receptors. Bladder homogenates were subjected to sodium dodecyl sulfate-polyacrylamide electrophoresis, followed by immunoblotting for T1R2/3 receptor expression. Rat bladder strips with and without urothelium were suspended in organ baths. The contractile response to 10 Hz electrical field stimulation was determined in the absence and presence of saccharin (Sigma-Aldrich®) (10(-8) to 10(-3) M). Responses to KCl in the absence and presence of saccharin, and saccharin plus zinc were also determined.

RESULTS

T1R2/3 sweet taste receptors were expressed in human and rat bladder urothelium. Immunostaining was evident in the plasma membrane of the 3 urothelial cell types, particularly umbrella cells. Immunoblotting revealed bands at expected molecular weights in human and rat bladder homogenates. Saccharin augmented rat bladder smooth muscle contraction due to electrical field stimulation only when urothelium was present in the bladder strip. Zinc blocked the enhancing effect of saccharin on responses to KCl.

CONCLUSIONS

T1R2/3 sweet taste receptors are expressed in human and rat bladder urothelium. Activation of these receptors by artificial sweeteners may result in augmented bladder contraction.

A healthy bladder: a consensus statement

A panel of experts in urology, urogynecology, nursing, and behavioral therapy convened in 2010 to discuss the importance of a healthy bladder on overall health. They determined that a consensus statement was necessary to raise awareness among the general public, healthcare providers, payors, and policymakers, with the goals of minimizing the impact of poor bladder health and stimulating primary prevention of bladder conditions. In this statement, 'healthy' bladder function is described, as well as internal and external factors that influence bladder health. It is suggested that primary prevention strategies should be aimed at providing education regarding normal lower urinary tract structures and functioning to the public, including patients and healthcare providers. This education may promote the achievement of optimal bladder health by increasing healthy bladder habits and behaviors, awareness of risk factors, healthcare seeking, and clinician engagement and reducing stigma and other barriers to treatment. Promoting optimal bladder health may reduce the personal, societal and economic impact of bladder conditions, including anxiety and depression and costs associated with conditions or diseases and their treatment. While adopting healthy bladder habits and behaviors and behaviors may improve or maintain bladder health, it is important to recognize that certain symptoms may indicate the presence of conditions that require medical attention; many bladder conditions are treatable with a range of options for most bladder conditions. Lastly, the authors propose clinical directives based on persuasive and convergent research to improve and maintain bladder health. The authors hope that this statement will lead to promotion and achievement of optimal bladder health, which may improve overall health and help minimize the effects of bladder conditions on the public, healthcare professionals, educators, employers, and payors. The advisors are in consensus regarding the recommendations for improving and maintaining bladder health presented herein.

Modification of rat detrusor muscle contraction by ascorbic acid and citric acid involving enhanced neurotransmitter release and Ca2+ influx

AIMS

Consumption of carbonated soft drinks is independently associated with the development of overactive bladder (OR 1.41, 95% Cl 1.02-1.95). We have shown previously that artificial sweeteners, present in carbonated soft drinks, enhanced detrusor muscle contraction. Other constituents of soft drinks are preservatives and antioxidants, we evaluated the effects of two of these, ascorbic acid and citric acid, on the contractile response of isolated rat bladder muscle strips.

METHODS

Detrusor muscle strips were suspended in a perfusion organ bath. We determined the effect of ascorbic acid and citric acid on the contractile responses to electrical field stimulation (EFS) in the absence and presence of atropine, carbachol, alpha, beta methylene ATP, potassium and calcium.

RESULTS

Ascorbic acid and citric acid (10(-7) M to 10(-3) M) enhanced the contractile response to 10 Hz EFS compared to control (P < 0.01). The frequency and amplitude of spontaneous bladder contractions were enhanced in the presence of ascorbic acid and citric acid by 14%, 21%, 21%, and 11% respectively. Ascorbic acid 10(-4) M significantly increased the atropine resistant response to EFS 5 Hz by 37% (P < 0.01) and inhibited contraction in response to carbachol 10(-4) M by 24%, (P < 0.05). Both ascorbic acid 10(-4) M and citric acid 10(-5) M significantly enhanced maximum contractile responses to alpha, beta methylene ATP, KCI and calcium compared to control.

CONCLUSIONS

Ascorbic acid and citric acid augmented bladder muscle contraction possibly by enhanced Ca(2+) influx. Presynaptic neurotransmitter release was enhanced by ascorbic acid. Carbonated beverages containing preservatives may aggravate symptoms of OAB.

Practical aspects of lifestyle modifications and behavioural interventions in the treatment of overactive bladder and urgency urinary incontinence

Behavioural interventions are effective treatments for overactive bladder (OAB) and urgency urinary incontinence (UUI). They are in part aimed at improving symptoms with patient education on healthy bladder habits and lifestyle modifications, including the establishment of normal voiding intervals, elimination of bladder irritants from the diet, management of fluid intake, weight control, management of bowel regularity and smoking cessation. Behavioural interventions also include specific training techniques aimed at re-establishing normal voiding intervals and continence. Training techniques include bladder training, which includes a progressive voiding schedule together with relaxation and distraction for urgency suppression, and multicomponent behavioural training, which, in conjunction with pelvic floor muscle (PFM) exercises, includes PFM contraction to control urgency and increase the interval between voids. Guidelines for the conservative treatment of OAB and UUI have been published by several organisations and the physiological basis and evidence for the effectiveness of behavioural interventions, including lifestyle modifications, in the treatment of OAB and UUI have been described. However, many primary care clinicians may have a limited awareness of the evidence supporting the often straight-forward treatment recommendations and guidance for incorporating behavioural interventions into busy primary care practices, because most of this information has appeared in the specialty literature. The purpose of this review is to provide an overview of behavioural interventions for OAB and UUI that can be incorporated with minimal time and effort into the treatment armamentarium of all clinicians that care for patients with bladder problems. Practical supporting materials that will facilitate the use of these interventions in the clinic are included; these can be used to help patients understand lifestyle choices and voiding behaviours that may improve function in patients experiencing OAB symptoms and/or UUI as well as promote healthy bladder behaviours and perhaps even prevent future bladder problems. Interventions for stress urinary incontinence are beyond the scope of this review.