Muscarinic receptors of the urinary bladder: detrusor, urothelial and prejunctional

Effect of intravenous lidocaine on catheter‑related bladder discomfort, postoperative pain and opioid requirement in complex fusion lumbar spinal surgery: a randomized, double blind, controlled trial

BACKGROUND

Catheter-related bladder discomfort (CRBD) and pain commonly arises postoperatively in patients who undergo intra-operative urinary catheterization. The study aims to demonstrate the effectiveness of intravenous lidocaine to prevent CRBD and postoperative pain in complex lumbar spinal surgery.

METHODS

Eighty male patients, aged 20-79 years, scheduled for elective fusion spine surgery at least two levels were randomly assigned to receive either intravenous lidocaine (1.5 mg/kg followed by 2 mg/kg/h) (Group L) or a parallel volume of normal saline (Group C). The primary outcome was incidence of moderate to severe CRBD in a postanesthetic care unit (PACU) between the two groups. Secondary outcomes included postoperative pain, 24-hour post operative opioid requirement, mild and moderate to severe CRBD at 1, 2, 6 and 24 h postoperatively, patient satisfaction on Global Perceived Effect Scale (GPES), and the adverse effects of lidocaine and surgical complications.

RESULTS

Group L showed a significantly lower incidence of moderate-to-severe CRBD compared to Group C in the PACU (P = 0.002) and at 1 h postoperatively (P = 0.039). Additionally, Group L experienced a significantly lower average pain scores compared to Group C at all time points (P < 0.001, P < 0.001, P = 0.001, P < 0.001 and P < 0.001 at 0, 1, 2, 6 and 24 h, respectively) and demonstrated a significantly reduced postoperative morphine requirement across all time intervals (P < 0.05). Group L also reported significantly higher satisfaction on GPES compared to group C (P < 0.001). No adverse outcome was observed in either group.

CONCLUSION

Intravenous lidocaine administration significantly reduced the incidence of moderate-to-severe CRBD at PACU and at 1 h postoperatively. Additionally, its use in complex spine surgery led to reductions in postoperative pain, opioid requirement, and improved patient satisfaction, without any observed side effects.

Comparison between the Efficacy of Sacral Erector Spina Plane Block and Pudendal Block on Catheter-Related Bladder Discomfort: A Prospective Randomized Study

Objective: Catheter-related bladder discomfort (CRBD) due to indwelling urinary catheterization in patients undergoing transurethral resection of the prostate (TURP) is difficult to tolerate and needs to be treated. This randomized prospective study aimed to compare the efficacy of sacral erector spinae plane block (SESPB) and pudendal nerve block (PNB) in reducing the incidence and score of CRBD. Methods: This study was conducted between November and December 2023. ASA I-III, fifty-four TURP patients were divided into two groups: Group 1 received SESPB (n = 27) and Group 2 received PNB (n = 27) under ultrasound guidance at the end of surgery. The incidence of CRBD, CRBD score, numerical rating scale (NRS) score, use of rescue analgesics, block performance time, first call for analgesics, patient satisfaction, and side effects were recorded for 24 h. Results: The incidence of CRBD was lowest at 33.3% and highest at 48.1% in Group 1 and lowest at 25.9% and highest at 48.1% in Group 2, with no significant difference between the groups at all measurement times. CRBD scores and NRS scores were low and similar between the two groups. Block performance times were 9 ± 1.7 min in SESPB and 20 ± 2.5 min in PNB, and there was a significant difference between the mean times (p < 0.001). Patient satisfaction was adequate and similar in both groups. Conclusions: SESPB demonstrated a similar decreasing effect to PNB on the incidence and scores of CRBD in the first 24 h following TURP operations. The duration of SESPB administration was shorter than PNB.

Giggle incontinence: a scoping review

Giggle incontinence (GI) is poorly described, defined, and understood. It is considered a bladder storage disorder in which laughter causes an uncontrollable episode of urinary incontinence that cannot be stopped until the bladder is completely emptied. It has been confused with stress urinary incontinence and overactive bladder. A thorough analysis of 26 articles on the subject of "giggle incontinence" and associated terms was performed, including all articles since the phrase first appeared. To date, 351 GI cases have been reported. It occurs mainly in women (69.5%) at 5 years of age, with a prevalence ranging from 8.4 to 16.2 years (average age of 12.4 years), and some cases have a family history of the disease (13-16.7%). This review discusses the historical background, current understanding, and challenges related to GI. It primarily affects females after the age of 5 years, causing complete bladder emptying during uncontrollable laughter. The exact cause is unknown, but hypotheses suggest involvement of the central nervous system. Diagnosis relies on clinical history, physical tests, and urine frequency evaluation. Management involves urotherapy techniques, biofeedback, and methylphenidate. Understanding GI will aid in developing more effective management techniques. IMPACT: Highlights limited awareness among healthcare professionals about giggle incontinence as a distinct condition, emphasizing the need for standardized diagnostic criteria and assessment tools. Addresses insufficient understanding of the underlying mechanisms and contributing factors, providing valuable insights for better diagnosis and treatment. Emphasizes the importance of patient education and support, calling for improved resources and counseling. Urges further research and evidence-based guidelines to enhance treatment strategies.

Evaluation of Food Effect on the Pharmacokinetics of Velufenacin, a New Muscarinic Receptor Antagonist, in Healthy Subjects

Velufenacin (DA-8010) is a new muscarinic receptor antagonist under development for the treatment of overactive bladder. This study aimed to evaluate the effect of food on the pharmacokinetics (PK) and safety of velufenacin in healthy subjects. A randomized, open-label, single-dose, 4-sequence, 4-treatment, 4-period crossover study was conducted. Subjects received a single oral dose of velufenacin 2.5 or 5 mg in a fasted or fed (high-fat meal) state in each period with a 7-day washout. PK parameters including maximum plasma concentration (Cmax ) and area under the concentration-time curve from time 0 to the last measurable point were compared between the fed and fasted states. Twenty-seven subjects completed the study. The mean area under the concentration-time curve from time 0 to the last measurable point of the velufenacin 2.5 and 5 mg doses under the fed condition showed a 1.5- and 1.3-fold increase, respectively, compared to the fasted condition. The corresponding values for Cmax were a 2.3- and 2.0-fold increase, respectively. The time to reach Cmax was comparable regardless of the dose or food intake, showing median values of 4.5-5.0 hours. These results suggest a modest increase of velufenacin absorption by food intake. Velufenacin was generally safe and well tolerated at the 2.5 and 5 mg doses regardless of food.

Age-dependent effects of the β3 adrenoceptor agonist CL316,243 on human and rat detrusor muscle strips

Motility of detrusor smooth muscle includes adrenergic relaxation and cholinergic contraction. Since the latter may be deregulated in overactive bladder (OAB) pathophysiology, anticholinergics are the standard therapy but occasionally less tolerated due to side effects such as dry mouth and constipation. β3 adrenoceptor agonists also alleviate OAB symptoms by relaxing the detrusor muscle. Their age dependence, however, is far from understood. To address this issue, we induced contractions with KCl (60 mM) and carbachol (from 10 nM to 100 μM) in the presence of the β3 adrenoceptor agonist CL316,243 (from 0.1 to 10 μM) in both human and rat muscle strips. Our results confirmed that both contractions were attenuated by β3 adrenoceptor activation in both species, but with differing age dependence. In humans, specimens from mid-life subjects showed a significantly more pronounced effect of CL316,243 in attenuating carbachol-induced contractions than those from aged subjects (Cohen's d of maximal attenuation: 1.82 in mid-life versus 0.13 in aged) without altering EC50. Conversely, attenuation of KCl responses by CL316,243 increased during ageing (Spearman correlation coefficient = -0.584, P<0.01). In rats, both KCl- and carbachol-induced contractions were significantly more attenuated by CL316,243 in samples from adolescent as compared to aged samples. Immunohistochemistry in human detrusor sections proved β3 adrenoreceptor abundance to remain unaltered during ageing. In conclusion, our findings suggest differential age-dependent changes in human β3 adrenoceptor-dependent attenuation of detrusor contraction in terms of electromechanical versus pharmacomechanical coupling; they may help understand the differential responsiveness of OAB patients to β3 agents.

Intracellular signaling pathways of muscarinic acetylcholine receptor-mediated detrusor muscle contractions

Acetylcholine plays an essential role in the regulation of detrusor muscle contractions, and antimuscarinics are widely used in the management of overactive bladder syndrome. However, several adverse effects limit their application and patients' compliance. Thus, this study aimed to further analyze the signal transduction of M2 and M3 receptors in the murine urinary bladder to eventually find more specific therapeutic targets. Experiments were performed on adult male wild-type, M2, M3, M2/M3, or Gαq/11 knockout (KO), and pertussis toxin (PTX)-treated mice. Contraction force and RhoA activity were measured in the urinary bladder smooth muscle (UBSM). Our results indicate that carbamoylcholine (CCh)-induced contractions were associated with increased activity of RhoA and were reduced in the presence of the Rho-associated kinase (ROCK) inhibitor Y-27632 in UBSM. CCh-evoked contractile responses and RhoA activation were markedly reduced in detrusor strips lacking either M2 or M3 receptors and abolished in M2/M3 KO mice. Inhibition of Gαi-coupled signaling by PTX treatment shifted the concentration-response curve of CCh to the right and diminished RhoA activation. CCh-induced contractile responses were markedly decreased in Gαq/11 KO mice; however, RhoA activation was unaffected. In conclusion, cholinergic detrusor contraction and RhoA activation are mediated by both M2 and M3 receptors. Furthermore, whereas both Gαi and Gαq/11 proteins mediate UBSM contraction, the activation at the RhoA-ROCK pathway appears to be linked specifically to Gαi. These findings may aid the identification of more specific therapeutic targets for bladder dysfunctions.NEW & NOTEWORTHY Muscarinic acetylcholine receptors are of utmost importance in physiological regulation of micturition and also in the development of voiding disorders. We demonstrate that the RhoA-Rho-associated kinase (ROCK) pathway plays a crucial role in contractions induced by cholinergic stimulation in detrusor muscle. Activation of RhoA is mediated by both M2 and M3 receptors as well as by Gi but not Gq/11 proteins. The Gi-RhoA-ROCK pathway may provide a novel therapeutic target for overactive voiding disorders.

Ageing influences detrusor contractions to prostaglandin, angiotensin, histamine and 5-HT (serotonin), independent to the Rho kinase and extracellular calcium pathways

Ageing is associated with deteriorating urinary bladder function and an increasing prevalence of disorders such as underactive bladder. There are suggestions that G protein-coupled receptor (GPCR) second messenger pathways are altered during ageing, rather than the receptor proteins themselves. The aim of this study was to identify age-related variations in GPCR activation systems in urinary bladder smooth muscle (detrusor). Isolated porcine detrusor strips were mounted in organ baths and contractile responses induced by receptor agonists were assessed and compared between juvenile (6 months) and adult (2 years) animals. The effects of drugs disrupting intracellular calcium signalling were also studied. Adult tissue was far more sensitive to stimulation by 5-hydroxytryptamine (42% greater increase than juvenile), prostaglandin-E2 (26% greater increase), and angiotensin-II (39% greater increase), however less sensitive to histamine. Although nifedipine and Y-27632 impacted the contraction to all agonists, there were no significant differences between juvenile and adult detrusor. Impairment of IP3-mediated calcium release by 2-aminoethyl diphenylborinate had no effect on any contractile activity, except for neurokinin-A which inhibited both juvenile and adult detrusor, and prostaglandin-E2 which inhibited juvenile. Carbachol, histamine, 5-hydroxytryptamine, and angiotensin-II were not affected by the application of 2-aminoethyl diphenylborinate. In conclusion, the contractile responses to all the GPCR agonists involved extracellular calcium influx and calcium sensitisation, but for prostaglandin-E2 the dependence on calcium from intracellular sources was greater in the younger animals.

Darifenacin Self-assembled Liquid Crystal Cubic Nanoparticles: a Sustained Release Approach for an Overnight Control of Overactive Bladder

The current study is regarding the development and characterization of Darifenacin-loaded self-assembled liquid crystal cubic nanoparticles (LCCN). An anhydrous approach was used for the preparation of these cubic nanoparticles using a hydrotropic agent (propylene glycol), with minimal energy input. Upon dispersion in aqueous medium, the system was successfully transformed to cubosomal nanoparticles counterpart as depicted by transmission electron micrographs. A Box-Behnken design was used to optimize formulation variables, namely A: amount of GMO, B: amount of Pluronic F127, C: amount of PG, and D: amount of HPMC. The design has generated 29 formulae which were tested regarding drug content uniformity, dispersibility in water, particle size, zeta potential, polydispersity index, and in vitro release behavior. The numerical optimization algorithms have generated an optimized formula with high desirability ≈ 1. The optimized formula displayed small particle size, good homogeneity, and zeta potential along with controlled in vitro release profile and ex vivo permeation through rabbit intestine. Thus, self-assembled LCCN might offer an alternative anhydrous approach for the preparation of cubosomal nanoparticles with controlled release profile for a possibly better control of overactive bladder syndrome which tremendously affect the overall life quality.

Molecular Influence of Resiniferatoxin on the Urinary Bladder Wall Based on Differential Gene Expression Profiling

Resiniferatoxin (RTX) is a potent capsaicin analog used as a drug for experimental therapy to treat neurogenic disorders associated with enhanced nociceptive transmission, including lower urinary tract symptoms. The present study, for the first time, investigated the transcriptomic profile of control and RTX-treated porcine urinary bladder walls. We applied multistep bioinformatics and discovered 129 differentially expressed genes (DEGs): 54 upregulated and 75 downregulated. Metabolic pathways analysis revealed five significant Kyoto Encyclopedia of Genes and Genomes (KEGG) items ('folate biosynthesis', 'metabolic pathways', 'sulfur relay system', 'sulfur metabolism' and 'serotonergic synapse') that were altered after RTX intravesical administration. A thorough analysis of the detected DEGs indicated that RTX treatment influenced the signaling pathways regulating nerve growth, myelination, axon specification, and elongation. Many of the revealed DEGs are involved in the nerve degeneration process; however, some of them were implicated in the initiation of neuroprotective mechanisms. Interestingly, RTX intravesical installation was followed by changes in the expression of genes involved in synaptic plasticity and neuromodulation, including 5-HT, H2S, glutamate, and GABA transmission. The obtained results suggest that the toxin may exert a therapeutic, antinociceptive effect not only by acting on TRPV1 receptors.

Potential revival of cholinesterase inhibitors as drugs in veterinary medicine

The cholinergic system is involved in the regulation of all organ systems and has acetylcholine (ACh) as almost its only neurotransmitter. Any substance is called cholinergic if it can alter the action of acetylcholine. Cholinesterases (ChEs) are enzymes that enable the hydrolysis of acetylcholine and in this way ensure homeostasis in cholinergic synapses. Cholinesterase inhibitors (ChEi) are a group of indirect-acting cholinergic agonists that influence the activity of the cholinergic system. Several compounds that can inhibit cholinesterases are of importance to veterinary medicine from pharmacological and toxicological perspective. The frequency of their use in veterinary medicine has fluctuated over the years and is now reduced to a minimum. They are mainly used in agriculture as pesticides, and some are rarely used as parasiticides for companion animals and livestock. In recent years, interest in the use of new cholinesterase inhibitors has increased since canine cognitive dysfunction (CCD) became a recognized and extensively studied disease. Similar to Alzheimer's disease (AD) in humans, CCD can be treated with cholinesterase inhibitors that cross the blood-brain barrier. In this review, the mammalian cholinergic system and the drugs that interact with cholinesterases are introduced. Cholinesterase inhibitors that can be used for the treatment of CCD are described in detail.

Myosin 5a in the Urinary Bladder: Localization, Splice Variant Expression, and Functional Role in Neurotransmission

Dysregulation of neurotransmission is a feature of several prevalent lower urinary tract conditions, but the mechanisms regulating neurotransmitter release in the bladder are not completely understood. The unconventional motor protein, Myosin 5a, transports neurotransmitter-containing synaptic vesicles along actin fibers towards the varicosity membrane, tethering them at the active zone prior to reception of a nerve impulse. Our previous studies indicated that Myosin 5a is expressed and functionally relevant in the peripheral nerves of visceral organs such as the stomach and the corpora cavernosa. However, its potential role in bladder neurotransmission has not previously been investigated. The expression of Myosin 5a was examined by quantitative PCR and restriction analyses in bladders from DBA (dilute-brown-nonagouti) mice which express a Myosin 5a splicing defect and in control mice expressing the wild-type Myosin 5a allele. Functional differences in contractile responses to intramural nerve stimulation were examined by ex vivo isometric tension analysis. Data demonstrated Myosin 5a localized in cholinergic nerve fibers in the bladder and identified several Myosin 5a splice variants in the detrusor. Full-length Myosin 5a transcripts were less abundant and the expression of splice variants was altered in DBA bladders compared to control bladders. Moreover, attenuation of neurally-mediated contractile responses in DBA bladders compared to control bladders indicates that Myosin 5a facilitates excitatory neurotransmission in the bladder. Therefore, the array of Myosin 5a splice variants expressed, and the abundance of each, may be critical parameters for efficient synaptic vesicle transport and neurotransmission in the urinary bladder.

InTrathecal mORphine, traNsversus Abdominis Plane Block, and tramaDOl Infusion for Catheter-Related Bladder Discomfort in Patients Undergoing Robot-Assisted Laparoscopic Prostatectomy (TORNADO): A Pilot Prospective Controlled Study

Catheter-related bladder discomfort (CRBD), affecting surgical patients requiring large catheters, is often intolerable. In this prospective controlled study, we compared the efficacy of three analgesic approaches in the management of CRBD. Here, 33 patients undergoing robot-assisted laparoscopic prostatectomy (RALP) were allocated to the following three groups: intrathecal morphine (IM), transversus abdominis plane block (TAP), and tramadol intravenous infusion (TI). The primary outcome was CRBD assessed at admission in the recovery room (RR) (T0), and 1 h (T1), 12 h (T2), and 24 h (T3) after surgery. The secondary outcomes included the following: Aldrete score; postoperative pain, measured with a numerical rate scale (NRS) at T0, T1, T2, and T3; postoperative opioid consumption; and flatus. The patients of the IM group showed significantly lower CRBD values over time compared to the patients of the TI group (p = 0.006). Similarly, NRS values decreased significantly over time in patients receiving IM compared to patients treated with TI (p < 0.0001). Postoperative nausea and vomiting did not differ among the three groups. Postoperative opioid consumption was significantly lower in the IM group compared to the other two groups. Most patients of the IM group (9 of 11) had flatus on the first postoperative day. In conclusion, IM may prevent CRBD and reduce pain perception and postoperative opioid consumption and expedite bowel function recovery.

Different interventions for preventing postoperative catheter-related bladder discomfort: a systematic review and meta-analysis

OBJECTIVE

Catheter-related bladder discomfort (CRBD) is a common complication of intraoperative urinary catheterization. Various studies have evaluated the efficacy of different interventions in postoperative CRBD. The present review was performed to assess the efficacy of these interventions.

METHODS

PubMed, Embase, and CENTRAL (Cochrane Central Register of Controlled Trials) databases were systematically searched to identify randomized controlled trials (RCTs) investigating the efficacy of different drugs for the prevention of postoperative CRBD. This review evaluated the incidence and severity of CRBD after different interventions at 0, 1, 2, and 6 h postoperatively.

RESULTS

Forty-five studies including 31 different drugs were analyzed. Eleven drugs were investigated in more than two RCTs, of which dexmedetomidine, gabapentin, tolterodine, tramadol, ketamine, nefopam, oxybutynin, pregabalin, and pudendal nerve block (PNB) generally showed significantly higher efficacy than controls postoperatively. Solifenacin only showed significant efficacy compared with the control at 0 h, and intravenous lidocaine only showed significant efficacy compared with the control at 6 h. There were insufficient trials to draw conclusions regarding atropine, butylscopolamine, chlorpheniramine, clonidine, darifenacin, diphenhydramine, glycopyrrolate, intravesical bupivacaine, ketamine-haloperidol, pethidine-haloperidol, ketorolac, lidocaine-prilocaine cream, magnesium, hyoscine n-butyl bromide, oxycodone, paracetamol, parecoxib, trospium, resiniferatoxin, or amikacin. However, all but pethidine-haloperidol and chlorpheniramine showed some efficacy at various time points compared with controls.

CONCLUSION

This review suggests that dexmedetomidine, gabapentin, tolterodine, tramadol, ketamine, nefopam, oxybutynin, pregabalin, and PNB are effective in preventing postoperative CRBD. Considering the efficacy and adverse effects of all drugs, dexmedetomidine and gabapentin were ranked best.

BoNT/A in the Urinary Bladder-More to the Story than Silencing of Cholinergic Nerves

Botulinum neurotoxin (BoNT/A) is an FDA and NICE approved second-line treatment for overactive bladder (OAB) in patients either not responsive or intolerant to anti-cholinergic drugs. BoNT/A acts to weaken muscle contraction by blocking release of the neurotransmitter acetyl choline (ACh) at neuromuscular junctions. However, this biological activity does not easily explain all the observed effects in clinical and non-clinical studies. There are also conflicting reports of expression of the BoNT/A protein receptor, SV2, and intracellular target protein, SNAP-25, in the urothelium and bladder. This review presents the current evidence of BoNT/A's effect on bladder sensation, potential mechanisms by which it might exert these effects and discusses recent advances in understanding the action of BoNT in bladder tissue.

The efficacy of dexmedetomidine for the prevention of catheter-related bladder discomfort: A systematic review and meta-analysis

BACKGROUND

The effective therapy to reduce postoperative catheter-related bladder discomfort (CRBD) remained unknown.

OBJECTIVE

We attempted to manage the systematic review and a meta-analysis to clarify the efficacy of dexmedetomidine (DEX) in potential prevention on CRBD.

METHODS

We performed the meta-analysis on randomized clinical trials (RCTs), and searched the databases from Web of Sciences, Embase and referred Cochrane Library published from October 2016 to September 2020. Data extraction was carefully conducted by 2 authors, respectively. Meta-analysis that was applied synthetically concerns the incidence and severity of CRBD and the treatment effect of DEX on CRBD.

RESULTS

We acquired 5 RCTs with interventions of DEX on CRBD. Meta-analysis showed DEX has significantly reduced the incidence and severity of CRBD compared with control at 0 hour (risk ratios [RR] = 0.40, 95% CI = 0.53-0.29, P < .01), 1 hour (RR = 0.44, 95% CI = 0.34-0.57, P < .01), and 2 hours (RR = 0.43, 95% CI = 0.32-0.58, P < .01) and 6 hours (RR = 0.43, 95% CI = 0.29-0.63, P < .01). DEX was also associated with lower incidence of moderate to severe CRBD at 0, 1, and 6 hours after surgery. There were no significant differences in adverse events other than bradycardia, hypotension, and hypertension.

CONCLUSION

The 5 RCTs showed great effectiveness in reducing the incidence and severity of the early and later postoperative CRBD. Meta-analysis showed that DEX interventions were useful in preventing the early and later postoperative CRBD without significant side effects.

The effect of amino acids on the bladder cycle: a concise review

The human bladder maintains a cycle of filling, storing, and micturating throughout an individual's lifespan. The cycle relies on the ability of the bladder to expand without increasing the intravesical pressure, which is only possible with the controlled relaxation of well-complaint muscles and the congruously organized construction of the bladder wall. A competent bladder outlet, which functions in a synchronous fashion with the bladder, is also necessary for this cycle to be completed successfully without deterioration. In this paper, we aimed to review the contemporary physiological findings on bladder physiology and examine the effects of amino acids on clinical conditions affecting the bladder, with special emphasis on the available therapeutic evidence and possible future roles of the amino acids in the treatment of the bladder-related disorders.

The effectiveness of parasympathomimetics for treating underactive bladder: A systematic review and meta-analysis

AIMS

Biological rationale suggests that parasympathomimetics (cholinergic receptor stimulating agents) could be beneficial for patients with underactive bladder. However, no systematic review with meta-analysis addressing potential benefits or adverse effects exists. The aim of this review was to assess the effectiveness, both benefits and harms, of using parasympathomimetics for the treatment of underactive bladder.

METHODS

The protocol was registered in PROSPERO, and searches undertaken in PubMed, Embase, and CENTRAL, including randomized and non-randomized controlled trials of patients with underactive bladder, comparing parasympathomimetic to placebo, no treatment, or other pharmaceuticals. Risk ratios, odds ratios, and mean differences were calculated.

RESULTS

Twelve trials with 3024 participants were included. There was a significant difference between parasympathomimetics and comparators (favoring parasympathomimetics) in the number of patients with urinary retention (risk ratio 0.55, 95% confidence interval [CI] 0.3-0.98, p = 0.04, low quality of evidence). There was no difference in mean postvoid volume overall (MD -41.4 ml, 95% CI -92.0 to 9.1, p = 0.11, low quality of evidence). There was a significant difference at up to 1 week post-intervention, favoring parasympathomimetics (MD -77.5 ml, 95% CI -90.9 to -64.1, p < 0.001, low quality of evidence), but no difference at 1 month post-intervention. There was no difference in adverse events (odds ratio 1.19, 95% CI 0.62-2.28, p = 0.6, moderate quality of evidence).

CONCLUSIONS

The evidence supporting the use of parasympathomimetics is of low quality, with relatively short follow-up durations. Overall, it is not possible to draw clear evidence-based conclusions from the current literature, presenting the use of parasympathomimetics for treating underactive bladder as a key area that requires future well-controlled clinical trials.

Antimuscarinic use among older adults with dementia and overactive bladder: a Medicare beneficiaries study

OBJECTIVES

This study examined the incidence and predictors of antimuscarinic medication use including non-selective antimuscarinics among older adults with dementia and overactive bladder (OAB).

METHODS

The study used a new-user cohort design involving older adults (≥65 years) with dementia and OAB based on 2013-2015 Medicare data. Antimuscarinics included non-selective (oxybutynin, tolterodine, trospium, fesoterodine) and selective (solifenacin, darifenacin) medications. Descriptive statistics and multivariable logistic regression models were used to determine the incidence and predictors of new antimuscarinic use including non-selective antimuscarinics, respectively.

RESULTS

Of the 3.38 million Medicare beneficiaries with dementia, over one million (1.05) had OAB (31.03%). Of those, 287,612 (27.39%) were reported as prevalent antimuscarinics users. After applying continuous eligibility criteria, 21,848 (10.34%) incident antimuscarinic users were identified (77.6% non-selective; 22.4% selective). Most frequently reported antimuscarinics were oxybutynin (56.3%) and solifenacin (21.4%). Multivariable analysis revealed that patients ≥75 years, of black race, and those with schizophrenia, epilepsy, delirium, and Elixhauser's score were less likely to initiate antimuscarinics. Women, those with abnormal involuntary movements, bipolar disorder, gastroesophageal reflux disease, insomnia, irritable bowel syndrome, muscle spasm/low back pain, neuropathic pain, benign prostatic hyperplasia, falls/fractures, myasthenia gravis, narrow-angle glaucoma, Parkinson's disease, syncope, urinary tract infection and vulvovaginitis were more likely to initiate antimuscarinics. Further, patients with muscle spasms/low back pain, benign prostatic hyperplasia and those taking higher level anticholinergics had lower odds of receiving non-selective antimuscarinics, whereas white patients, black patients and those with schizophrenia and delirium were more likely to receive them.

CONCLUSIONS

Nearly one-third of dementia patients had OAB and over one-fourth of them used antimuscarinics. Majority of the incident users were prescribed non-selective antimuscarinics with several demographic and clinical factors contributing to their use. Given the high prevalence of OAB among dementia patients, there is a need to optimize their antimuscarinic use, considering their vulnerability for anticholinergic adverse effects.

Purinergic signalling in the urinary bladder - When function becomes dysfunction

Knowledge of the participation of ATP and related purines in urinary tract physiology has been established over the last five decades through the work of many independent groups, inspired by, and building on the pioneering studies of Professor Geoffrey Burnstock and his coworkers. As part of a series of reviews in this tribute edition, the present article summarises our current understanding of purines and purinergic signalling in modulating and regulating urinary tract function. Purinergic mechanisms underlying the origin of bladder pain; sensations of bladder filling and urinary tract motility; and regulation of detrusor smooth muscle contraction are described, encompassing the relevant history of discovery and consolidation of knowledge as methodologies and pharmacological tools have developed. We consider normal physiology, including development and ageing and then move to pathophysiology, discussing the causal and consequential contribution of purinergic signalling mechanism and their constituent components (receptors, signal transduction, effector molecules) to bladder dysfunction.

The inhibitory effect of trimetazidine on detrusor contractility - a potential repositioning of trimetazidine for the treatment of overactive bladder

OBJECTIVES

This study aimed to identify the effect of trimetazidine (TMZ), an antianginal drug, on detrusor smooth muscle (DSM) contractility and its possible mechanisms of action.

METHODS

We performed in-vitro contractility studies on isolated mouse DSM strips and investigated the effect of TMZ on Ca2+ levels in fura-2-loaded A7r5 cells.

KEY FINDINGS

TMZ (300 or 1000 µM) inhibited carbachol (CCh)- and KCl-induced contractions and produced a concentration-dependent (10-1000 µM) relaxation in KCl-precontracted DSM strips. TMZ-induced relaxation was markedly decreased by BaCl2, an inward-rectifying K+ channel blocker, but was not altered by preincubation with tetraethylammonium, glibenclamide, 4-aminopyridine, propranolol, L-NAME or methylene blue. TMZ (300 or 1000 µM) reduced both the CaCl2-induced contraction of depolarized DSM strips under Ca2+-free conditions and the CCh-induced contraction of DSM strips preincubated with nifedipine in Ca2+-containing Krebs solution. Furthermore, TMZ (1000 µM) significantly decreased the Ca2+ levels in fura-2-loaded A7r5 cells.

CONCLUSIONS

TMZ decreased DSM contractility and caused a concentration-dependent relaxation of the tissue possibly through its actions on Ca2+ transients and K+ channels. Our results provide preclinical evidence that TMZ would be a potential candidate to treat disorders related to the overactivity of the bladder.

Comparative risk of adverse outcomes associated with nonselective and selective antimuscarinic medications in older adults with dementia and overactive bladder

OBJECTIVE

The differential muscarinic receptor selectivity could cause selective antimuscarinics to offer advantages over nonselective agents with respect to adverse effects. The objective was to examine the comparative risk of falls/fractures and all-cause hospitalizations among older adults with dementia and overactive bladder (OAB) using nonselective and selective antimuscarinics METHODS/DESIGN: A retrospective cohort study design was conducted among older patients with dementia and OAB using incident antimuscarinics. The primary exposure was classified as nonselective (oxybutynin, tolterodine, trospium, and fesoterodine) and selective (solifenacin and darifenacin). Cox proportional-hazards regression using inverse probability of treatment weighting (IPTW) evaluated the risk of falls/fractures and all-cause hospitalizations within 6 months of nonselective and selective antimuscarinic use.

RESULTS

The study cohort consisted of 13,896 (76.9%) nonselective and 4,179 (23.1%) selective antimuscarinic incident users. The unadjusted falls/fractures rate was 27.14% (3,772) for nonselective and 24.55% (1,026) for selective users (p-value< 0.01). The unadjusted all-cause hospitalizations rate was 24.14% (3,354) for nonselective and 21.58% (902) for selective users (p-value <0.01). The IPTW models did not find a significant difference in the risk of falls/fractures (Hazard Ratio [HR] 1.03; 95% Confidence Interval [CI] 0.99-1.07) and risk of all-cause hospitalizations (HR 1.04; 95% CI 0.99-1.08) between nonselective and selective antimuscarinics. Several sensitivity analyses corroborated the main findings.

CONCLUSIONS

The study did not find a differential risk of falls/fractures and all-cause hospitalizations in older adults with dementia and OAB using nonselective and selective antimuscarinics. More research is needed to understand the role of pharmacodynamics and pharmacokinetics in the safety profile of antimuscarinics in dementia.

Overcoming Obstacles to Targeting Muscarinic Receptor Signaling in Colorectal Cancer

Despite great advances in our understanding of the pathobiology of colorectal cancer and the genetic and environmental factors that mitigate its onset and progression, a paucity of effective treatments persists. The five-year survival for advanced, stage IV disease remains substantially less than 20%. This review examines a relatively untapped reservoir of potential therapies to target muscarinic receptor expression, activation, and signaling in colorectal cancer. Most colorectal cancers overexpress M₃ muscarinic receptors (M₃R), and both in vitro and in vivo studies have shown that activating these receptors stimulates cellular programs that result in colon cancer growth, survival, and spread. In vivo studies using mouse models of intestinal neoplasia have shown that using either genetic or pharmacological approaches to block M₃R expression and activation, respectively, attenuates the development and progression of colon cancer. Moreover, both in vitro and in vivo studies have shown that blocking the activity of matrix metalloproteinases (MMPs) that are induced selectively by M₃R activation, i.e., MMP1 and MMP7, also impedes colon cancer growth and progression. Nonetheless, the widespread expression of muscarinic receptors and MMPs and their importance for many cellular functions raises important concerns about off-target effects and the safety of employing similar strategies in humans. As we highlight in this review, highly selective approaches can overcome these obstacles and permit clinicians to exploit the reliance of colon cancer cells on muscarinic receptors and their downstream signal transduction pathways for therapeutic purposes.

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.

Risk of Mortality Associated with Non-selective Antimuscarinic medications in Older Adults with Dementia: a Retrospective Study

BACKGROUND

Selective antimuscarinics may offer a favorable safety profile over non-selective antimuscarinics for the management of overactive bladder (OAB) in patients with dementia.

OBJECTIVE

To test the hypothesis that non-selective antimuscarinics are associated with increased risk of mortality compared to selective antimuscarinics in older adults with dementia and OAB.

DESIGN

Propensity score-matched retrospective new-user cohort design among Medicare beneficiaries in community settings.

PATIENTS

Older adults with dementia and OAB with incident antimuscarinic use.

MAIN MEASURES

The primary exposure was antimuscarinic medications classified as non-selective (oxybutynin, tolterodine, trospium, fesoterodine) and selective (solifenacin, darifenacin) agents. All-cause mortality within 180 days of incident antimuscarinic use formed the outcome measure. New users of non-selective and selective antimuscarinics were matched on propensity scores using the Greedy 5 → 1 matching technique. Cox proportional-hazards model stratified on matched pairs was used to evaluate the risk of mortality associated with the use of non-selective versus selective antimuscarinics in the sample.

KEY RESULTS

The study identified 16,955 (77.6%) non-selective antimuscarinic users and 4893 (22.4%) selective antimuscarinic users. Propensity score matching yielded 4862 patients in each group. The unadjusted mortality rate at 180 days was 2.6% (126) for non-selective and 1.6% (78) for selective antimuscarinic users in the matched cohort (p value < 0.01). The Cox model stratified on matched pairs found 50% higher risk of 180-day mortality with non-selective antimuscarinics as compared to selective ones (hazard ratio (HR) 1.50; 95% confidence interval (CI) 1.04-2.16). The study findings remained consistent across multiple sensitivity analyses.

CONCLUSIONS

Use of non-selective antimuscarinics was associated with a 50% increase in mortality risk among older adults with dementia and OAB. Given the safety concerns regarding non-selective antimuscarinic agents, there is a significant need to optimize their use in the management of OAB for older patients with dementia.

Antispasmodic effect of hydroalcoholic and flavonoids extracts of Dracocephalum kotschyi on rabbit bladder

Introduction: Dracocephalum kotschyi extract has antispasmodic activities on smooth muscle including ileum, uterus and trachea. The objective of this research was to investigate antispasmodic activity of hydroalcoholic and flavonoids extracts of D. kotschyi on rabbit bladder contractions. Methods: Rabbits were euthanized by carbon dioxide asphyxiation and the whole bladder was dissected out and immersed in the Tyrode’s solution. Longitudinal bladder strips were mounted vertically in an organ bath at 37°C and gassed continuously with O2 . Bladder strips were contracted with acetylcholine (ACh), KCl, or electrical field stimulation (EFS). Isotonic tension of the tissue was recorded before and after addition of hydroalcoholic or flavonoids rich extracts of D. kotschyi. Nifedipine and propantheline were used as standard drugs. Results: Standard drug propantheline, prevented bladder phasic contraction induced by ACh (1µM) without affecting KCl response. On the other hand, cumulative addition of nifedipine attenuated the tonic contractions induced by KCl (20mM) on bladder smooth muscle. Hydroalcoholic and flavonoids extracts of D. kotschyiat concentration ranges of 10-320 µg/ mL in a concentration dependent way inhibited bladder tonic contraction induced by KCl (n=6). Both extracts also in a concentration-dependent manner relaxed EFS and ACh-induced contractions (range, 20–1280 µg/mL) of bladder smooth muscle in vitro. Complete inhibition was achieved with the highest used concentrations of the extracts. The inhibitory effect of the extract was reversible following washing the tissues with fresh Tyrode’s solution. Conclusion: This study clearly demonstrated that D. kotschyi extracts were able to prevent contractions induced by ACh, KCl or EFS in isolated rabbit bladder. This means that people consuming this medicinal plant may face urinary retention which could be a problem for patients with prostate hypertrophy. On the other hand, this plant might be useful in patients with urinary incontinence. However, its usefulness must be assessed in the controlled clinical trials.

NK2 receptor-mediated detrusor muscle contraction involves Gq/11-dependent activation of voltage-dependent Ca2+ channels and the RhoA-Rho kinase pathway

Tachykinins (TKs) are involved in both the physiological regulation of urinary bladder functions and development of overactive bladder syndrome. The aim of the present study was to investigate the signal transduction pathways of TKs in the detrusor muscle to provide potential pharmacological targets for the treatment of bladder dysfunctions related to enhanced TK production. Contraction force, intracellular Ca²⁺ concentration, and RhoA activity were measured in the mouse urinary bladder smooth muscle (UBSM). TKs and the NK2 receptor (NK2R)-specific agonist [β-Ala⁸]-NKA(4-10) evoked contraction, which was inhibited by the NKR2 antagonist MEN10376. In Gα_q/11-deficient mice, [β-Ala⁸]-NKA(4-10)-induced contraction and the intracellular Ca²⁺ concentration increase were abolished. Although G_q/11 proteins are linked principally to phospholipase Cβ and inositol trisphosphate-mediated Ca²⁺ release from intracellular stores, we found that phospholipase Cβ inhibition and sarcoplasmic reticulum Ca²⁺ depletion failed to have any effect on contraction induced by [β-Ala⁸]-NKA(4-10). In contrast, lack of extracellular Ca²⁺ or blockade of voltage-dependent Ca²⁺ channels (VDCCs) suppressed contraction. Furthermore, [β-Ala⁸]-NKA(4-10) increased RhoA activity in the UBSM in a G_q/11-dependent manner and inhibition of Rho kinase with Y-27632 decreased contraction force, whereas the combination of Y-27632 with either VDCC blockade or depletion of extracellular Ca²⁺ resulted in complete inhibition of [β-Ala⁸]-NKA(4-10)-induced contractions. In summary, our results indicate that NK2Rs are linked exclusively to G_q/11 proteins in the UBSM and that the intracellular signaling involves the simultaneous activation of VDCC and the RhoA-Rho kinase pathway. These findings may help to identify potential therapeutic targets of bladder dysfunctions related to upregulation of TKs.

Comparative effectiveness of interventions for managing postoperative catheter-related bladder discomfort: a systematic review and network meta-analysis

BACKGROUND

Although many drugs or interventions have been studied to manage catheter-related bladder discomfort (CRBD), their comparative effectiveness is unknown. We attempted to assess the comparative effectiveness of the strategies to manage CRBD in patients undergoing urologic surgery including amikacin, solifenacin, darifenacin, butylscopolamine, dexmedetomidine, gabapentin, glycopyrrolate, ketamine, oxybutynin, resiniferatoxin, tolterodine, tramadol, caudal block, dorsal penile nerve block, lidocaine-prilocaine cream.

METHODS

We performed an arm-based network meta-analysis including 29 trials with 2841 participants. Goodness of model fit was evaluated by deviance information criteria (DIC). The incidence of CRBD at 0, 1, and 6 h after surgery and the incidence of moderate to severe CRBD at 0, 1, and 6 h after surgery were compared.

RESULTS

Random effect model was selected according to DIC. Most of the drugs significantly decreased the incidence of CRBD except amikacin, tramadol at 0 and 1 h after surgery. Dexmedetomidine, solifenacin, caudal block, dorsal penile nerve block, resiniferatoxin, and gabapentin 1200 mg p.o. significantly decreased the incidence of CRBD at 6 h after surgery (gabapentin 1200: Odds ratio [OR] 0.02; SUCRA 95.6). Dexmedetomidine and tolterodine significantly decreased the incidence of moderate to severe CRBD at 0, 1, and 6 h after surgery (tolterodine at 6 h: OR 0.05; SUCRA 73.7).

CONCLUSIONS

Gabapentin was ranked best regarding the overall incidence of CRBD, while tolterodine was ranked best in reducing the severity of CRBD. However, a firm conclusion cannot be made from our analysis due to small-study number and heterogeneity regarding study setting and outcome measurement.

Histamine modulation of urinary bladder urothelium, lamina propria and detrusor contractile activity via H1 and H2 receptors

The mechanisms underlying bladder contractile disorders such as overactive bladder are not fully understood, and there is limited understanding of the receptor systems modulating spontaneous bladder contractions. We investigated the potential for histamine to have a role in mediating contractility of the urothelium with lamina propria (U&LP) or detrusor via the H1-H4 histamine receptor subtypes. Isolated strips of porcine U&LP or detrusor smooth muscle were mounted in gassed Krebs-bicarbonate solution and responses to histamine obtained in the absence and presence of selective receptor antagonists. The presence of histamine increases the frequency of U&LP spontaneous phasic contractions and baseline tensions. In response to histamine, H1-antagonists pyrilamine, fexofenadine and cyproheptadine were effective at inhibiting contractile responses. Cimetidine (H2-antagonist) enhanced increases in baseline tension in response histamine, whereas amthamine (H2-agonist) induced relaxation. Although thioperamide (H3/H4-antagonist) increased baseline tension responses to histamine, selective H1/H2-receptor antagonism revealed no influence of these receptors. In detrusor preparations, pyrilamine, fexofenadine and cyproheptadine were effective at inhibiting baseline tension increases in response to histamine. Our findings provide evidence that histamine produces contractile responses both in the U&LP and detrusor via the H1-receptor, and this response is significantly inhibited by activation of the H2-receptor in the U&LP but not the detrusor.

Tramadol for the treatment of catheter-related bladder discomfort: a randomized controlled trial

Background

Intra-operative urinary catheterization frequently causes postoperative catheter related bladder discomfort (CRBD) during recovery. We conducted this study to evaluate the efficacy of tramadol, which with muscarinic receptor antagonist property, as a treatment for CRBD.

Methods

Ninety patients who underwent elective gynecological surgery and complained of CRBD in the (PACU) were randomized into three groups of 30 each. Group A received normal saline, group B 1 mg/kg tramadol, and group C 1.5 mg/kg tramadol. The medication was administered from the Murphy’s dropper with a slow drip, and the severity of CRBD (none, mild, moderate, and severe) and postoperative pain were assessed after 0, 0.5, 1, 2 and 6 h.

Results

The severity of CRBD was reduced in group C compared with that in groups A and B at 1 h, and in groups C and B compared with that in group A at 2 h. The incidence of CRBD was reduced in group C compared with that in groups A and B at 2 h, and in group C compared with that in group A at 6 h. The visual analog scale (VAS) was reduced in group C compared with that in groups A and B at all time intervals. No differences in adverse effects were observed.

Conclusions

Tramadol 1.5 mg/kg was more effective than tramadol 1 mg/kg in treating CRBD and reducing postoperative pain, without significant side effects.

Trial registration

ChiCTR1800016390. Registered on 30 May 2018.

Highly specific detection of muscarinic M3 receptor, G protein interaction and intracellular trafficking in human detrusor using Proximity Ligation Assay (PLA)

PURPOSE

Muscarinic acetylcholine receptors (mAChRs) regulate a number of important physiological functions. Alteration of mAChR expression or function has been associated in the etiology of several pathologies including functional bladder disorders (e.g bladder pain syndrome/interstitial cystitis - BPS/IC). In a previous study we found specific mAChR expression patterns associated with BPS/IC, while correlation between protein and gene expression was lacking. Posttranslational regulatory mechanisms, e.g. altered intracellular receptor trafficking, could explain those differences. In addition, alternative G protein (GP) coupling could add to the pathophysiology via modulation of muscarinic signaling. In our proof-of-principle study, we addressed these questions in situ. We established PLA in combination with confocal laserscanning microscopy (CLSM) and 3D object reconstruction for highly specific detection and analysis of muscarinic 3 receptors (M3), G protein (GP) coupling and intracellular trafficking in human detrusor samples.

MATERIAL AND METHODS

Paraffin sections of formalin-fixed bladder tissue (FFPE) of BPS/IC patients receiving transurethral biopsy were examined by Cy3-PLA for M3 expression, coupling of M3 to GPs (G_αq/11, G_αs, G_αi) and interaction of M3 with endocytic regulator proteins. Membranes were labeled with wheat germ agglutinin-Alexa Fluor^®488, nuclei were stained with DAPI. Object density and co-localization were analyzed in 3D-reconstruction of high resolution confocal z-stacks.

RESULTS

Confocal image stack processing resulted in well demarcated objects. Calculated receptor densities correlated significantly with existing confocal expression data, while significantly improved specificity of M3 detection by PLA was verified using bladder tissue samples from transgenic mice. 50-60% of the M3 receptor complexes were plasma membrane associated in human bladder detrusor. Application of PLA for M3 and GPs allowed visualization of M3-GP interactions and revealed individual GP-subtype coupling patterns. Detection of M3 interactions with endocytic trafficking proteins by PLA resulted in object sizes correlating with well-documented vesicle sizes of the endocytosis pathway.

CONCLUSION

PLA enabled highly specific detection of M3 receptor expression, demonstration of M3/GP differential coupling and intracellular M3 trafficking in human detrusor smooth muscle cells. This new approach minimized background fluorescence and antibody cross-reactions resulting from single antibody application, and enhanced specificity due to the use of two primary antibodies. Use of subcellular markers allowed visualization of subcellular receptor location. PLA/CLSM allows analyses of muscarinic "receptor - G protein - promiscuity" and intracellular trafficking even in bladder paraffin sections and may give new insights into the etiology and pathology of BPS/IC.

Muscarinic receptors 2 and 5 regulate bitter response of urethral brush cells via negative feedback

We have recently identified a cholinergic chemosensory cell in the urethral epithelium, urethral brush cell (UBC), that, upon stimulation with bitter or bacterial substances, initiates a reflex detrusor activation. Here, we elucidated cholinergic mechanisms that modulate UBC responsiveness. We analyzed muscarinic acetylcholine receptor (M1-5 mAChR) expression by using RT-PCR in UBCs, recorded [Ca²⁺]_i responses to a bitter stimulus in isolated UBCs of wild-type and mAChR-deficient mice, and performed cystometry in all involved strains. The bitter response of UBCs was enhanced by global cholinergic and selective M2 inhibition, diminished by positive allosteric modulation of M5, and unaffected by M1, M3, and M4 mAChR inhibitors. This effect was not observed in M2 and M5 mAChR-deficient mice. In cystometry, M5 mAChR-deficient mice demonstrated signs of detrusor overactivity. In conclusion, M2 and M5 mAChRs attenuate the bitter response of UBC via a cholinergic negative autocrine feedback mechanism. Cystometry suggests that dysfunction, particularly of the M5 receptor, may lead to such symptoms as bladder overactivity.-Deckmann, K., Rafiq, A., Erdmann, C., Illig, C., Durschnabel, M., Wess, J., Weidner, W., Bschleipfer, T., Kummer, W. Muscarinic receptors 2 and 5 regulate bitter response of urethral brush cells via negative feedback.

Adaptive changes of telocytes in the urinary bladder of patients affected by neurogenic detrusor overactivity

Urinary bladder activity involves central and autonomic nervous systems and bladder wall. Studies on the pathogenesis of voiding disorders such as the neurogenic detrusor overactivity (NDO) due to suprasacral spinal cord lesions have emphasized the importance of an abnormal handling of the afferent signals from urothelium and lamina propria (LP). In the LP (and detrusor), three types of telocytes (TC) are present and form a 3D-network. TC are stromal cells able to form the scaffold that contains and organizes the connective components, to serve as guide for tissue (re)-modelling, to produce trophic and/or regulatory molecules, to share privileged contacts with the immune cells. Specimens of full thickness bladder wall from NDO patients were collected with the aim to investigate possible changes of the three TC types using histology, immunohistochemistry and transmission electron microscopy. The results show that NDO causes several morphological TC changes without cell loss or network interruption. With the exception of those underlying the urothelium, all the TC display signs of activation (increase in Caveolin1 and caveolae, αSMA and thin filaments, Calreticulin and amount of cisternae of the rough endoplasmic reticulum, CD34, euchromatic nuclei and large nucleoli). In all the specimens, a cell infiltrate, mainly consisting in plasma cells located in the vicinity or taking contacts with the TC, is present. In conclusion, our findings show that NDO causes significant changes of all the TC. Notably, these changes can be interpreted as TC adaptability to the pathological condition likely preserving each of their peculiar functions.

Sevoflurane vs. propofol in post-operative catheter-related bladder discomfort: a prospective randomized study

BACKGROUND

Post-operative catheter-related bladder discomfort (CRBD) causes increased emergence agitation. Muscarinic receptor activation is a major mechanism in CRBD development. Experimental studies showed that sevoflurane has anti-muscarinic effects whereas propofol does not. Our hypothesis was that sevoflurane anaesthesia would reduce the incidence of CRBD following bladder surgery.

METHODS

In total, 82 patients undergoing transurethral bladder tumour excision (TURBT) were assigned randomly to two groups according to the maintenance anaesthetic agent received: sevoflurane (n = 41) or propofol (n = 41). The incidence of CRBD was evaluated at 0, 1, 6 and 24 h post-operatively. The number of patients treated with a rescue medication (tramadol) for CRBD was noted.

RESULTS

The incidence of CRBD at post-operative 1 h was lower in the sevoflurane group than that in the propofol group (59% vs. 85%; P = 0.007). The differences in CRBD were 27% and 22% at 0 and 6 h post-operatively (P = 0.008 and 0.047, respectively). CRBD occurred in 27 (66%) patients in the sevoflurane group vs. 38 (93%) in the propofol group from 0 to 24 h post-operatively (P = 0.005). The number of patients treated with tramadol was lower in the sevoflurane group (13 [22%] vs. 22 [54%]; P = 0.044).

CONCLUSION

Sevoflurane, as a maintenance in general anaesthesia, decreased the incidence of early post-operative CRBD and tramadol requirements in patients undergoing TURBT, compared with propofol.

Changes of Bladder M1,3 Muscarinic Receptor Expression in Rats Fed with Short-Term/Long-Term High-Fat Diets

OBJECTIVES

To investigate the effect of high-fat diet (HFD) on bladder M_1,3 muscarinic receptor expression and contractile function in the rat.

METHODS

Eight-week-old male rats were divided into two groups including one with HFD for 8 weeks (short-term) and the other for 24 weeks (long-term). Each group was compared to age-matched rats fed with normal chow as controls. The body weight, food intake amount and blood biochemistry were monitored. Bladder muscle contractile responses to acetylcholine (0.1-10 μM), bethanechol (10 μM) and KCl (50 mM) were studied in an organ bath set-up. Bladder M₁ and M₃ muscarinic receptor protein expressions were measured by Western blotting analysis.

RESULTS

Increase in body weight as well as blood triglyceride, cholesterol and sugar levels compared to controls were noted in both 8- and 24-week HFD rats. Eating appetite change with increased food and water intakes was noted in the HFD rats. Significantly decreased bladder contractile responses to acetylcholine and bethanechol were shown in both HFD groups. On the other hand, decreased bladder contractile response to KCl was demonstrated in the 24-week group but not the 8-week group. The expressions of bladder M₁ and M₃ muscarinic receptor proteins were significantly and progressively decreased by HFD feeding from 8 to 24 weeks.

CONCLUSIONS

High-fat diet induces obesity and polyphagia in rats. Short-term and long-term HFD feeding decrease rat bladder M₁ and M₃ receptor expressions as well as contractile responses to the agonistic stimulation. In addition, bladder muscle dysfunction develops after long-term HFD feeding.

The Functional Haplotypes of CHRM3 Modulate mRNA Expression and Associate with Bladder Cancer among a Chinese Han Population in Kaohsiung City

Bladder cancer is one of the major cancer types and both environmental factors and genetic background play important roles in its pathology. Kaohsiung is a high industrialized city in Taiwan, and here we focused on this region to evaluate the genetic effects on bladder cancer. Muscarinic acetylcholine receptor M3 (CHRM3) was reported as a key receptor in different cancer types. CHRM3 is located at 1q42-43 which was reported to associate with bladder cancer. Our study attempted to delineate whether genetic variants of CHRM3 contribute to bladder cancer in Chinese Han population in south Taiwan. Five selected SNPs (rs2165870, rs10802789, rs685550, rs7520974, and rs3738435) were genotyped for 30 bladder cancer patients and 60 control individuals and genetic association studies were performed. Five haplotypes (GTTAT, ATTGT, GCTAC, ACTAC, and ACCAC) were found significantly associated with low CHRM3 mRNA level and contributed to increased susceptibility of bladder cancer in Kaohsiung city after rigid 10000 consecutive permutation tests. To our knowledge, this is the first genetic association study that reveals the genetic contribution of CHRM3 gene in bladder cancer etiology.

Effects of glycopyrrolate premedication on preventing postoperative catheter-related bladder discomfort in patients receiving ureteroscopic removal of ureter stone

Background

Glycopyrrolate given as reversing agents of muscle relaxants has been reported to be effective in reducing postoperative catheter-related bladder discomfort (CRBD). However, it remains unclear whether glycopyrrolate as premedication is also effective. This study aims to investigate the effectiveness of glycopyrrolate as premedication on preventing CRBD in the post-anesthesia care unit (PACU).

Methods

Eighty-three patients who received elective ureteroscopic removal of ureteral stone were randomly assigned to the control (n = 43) or the glycopyrrolate group (n = 40). The glycopyrrolate group was treated with glycopyrrolate 0.3 mg as premedication while the control group received 0.9% saline 1.5 ml. The incidence and severity of CRBD and pain score using numerical rating scale (NRS) were measured in the PACU.

Results

The incidence of CRBD (26 of 40 patients vs. 41 of 43 patients, relative risk [RR] = 0.68, 95% Confidence interval [CI] = 0.53–0.86, P = 0.001) and the moderate to severe CRBD incidence (6 of 40 patients vs. 20 of 43 patients, RR = 0.32, 95% CI = 0.14–0.72, P = 0.002) were lower in the glycopyrrolate group than in the control group. Also, postoperative pain NRS score was found to be lower in the glycopyrrolate group (median = 1 [Q1 = 0, Q3 = 2]) compared to the control group (3 [1, 5], median difference = 1.00, 95% CI = 0.00–2.00, P = 0.002).

Conclusions

The use of glycopyrrolate 0.3 mg as premedication in patients receiving ureteroscopic removal of ureteral stone reduced the incidence and severity of CRBD, and decreased postoperative pain in the PACU.

Influence of urothelial or suburothelial cholinergic receptors on bladder reflexes in chronic spinal cord injured cats

The effects of intravesical administration of a muscarinic receptor agonist (oxotremorine-M, OXO-M) and antagonist (atropine methyl nitrate, AMN) and of a nicotinic receptor agonist (nicotine) and antagonist (hexamethonium, C₆) on reflex bladder activity were investigated in conscious female chronic spinal cord injured (SCI) cats using cystometry. OXO-M (50μM) decreased bladder capacity (BC) for triggering micturition contractions, increased maximal micturition pressure (MMP), increased frequency and area under the curve of pre-micturition contractions (PMC-AUC). Nicotine (250μM) decreased BC, increased MMP, but did not alter PMC-AUC. The effects of OXO-M on BC and PMC-AUC were suppressed by intravesical administration of AMN (50-100μM), and the effects of nicotine were blocked by hexamethonium (1mM). Antagonists infused intravesically alone did not alter reflex bladder activity. However, AMN (0.2mg/kg, subcutaneously) decreased PMC-AUC. 8-OH-DPAT (0.5mg/kg, s.c.), a 5-HT_1A receptor agonist, suppressed the OXO-M-induced decrease in BC but not the enhancement of PMC-AUC. These results indicate that activation of cholinergic receptors located near the lumenal surface of the bladder modulates two types of reflex bladder activity (i.e., micturition and pre-micturition contractions). The effects may be mediated by activation of receptors on suburothelial afferent nerves or receptors on urothelial cells which release transmitters that can in turn alter afferent excitability. The selective action of nicotine on BC, while OXO-M affects both BC and PMC-AUC, suggests that micturition reflexes and PMCs are activated by different populations of afferent nerves. The selective suppression of the OXO-M effect on BC by 8-OH-DPAT without altering the effect on PMCs supports this hypothesis. The failure of intravesical administration of either AMN or hexamethonium alone to alter bladder activity indicates that cholinergic receptors located near the lumenal surface do not tonically regulate bladder reflex mechanisms in the SCI cat.

Anatomy and physiology of the lower urinary tract

Functions of the lower urinary tract to store and periodically eliminate urine are regulated by a complex neural control system in the brain, spinal cord, and peripheral autonomic ganglia that coordinates the activity of smooth and striated muscles of the bladder and urethral outlet. Neural control of micturition is organized as a hierarchic system in which spinal storage mechanisms are in turn regulated by circuitry in the rostral brainstem that initiates reflex voiding. Input from the forebrain triggers voluntary voiding by modulating the brainstem circuitry. Many neural circuits controlling the lower urinary tract exhibit switch-like patterns of activity that turn on and off in an all-or-none manner. The major component of the micturition switching circuit is a spinobulbospinal parasympathetic reflex pathway that has essential connections in the periaqueductal gray and pontine micturition center. A computer model of this circuit that mimics the switching functions of the bladder and urethra at the onset of micturition is described. Micturition occurs involuntarily during the early postnatal period, after which it is regulated voluntarily. Diseases or injuries of the nervous system in adults cause re-emergence of involuntary micturition, leading to urinary incontinence. The mechanisms underlying these pathologic changes are discussed.

The Inhibitory Mechanism of Gentamicin on Electrical Field Stimulation Response in Rat Bladder Smooth Muscle

To see the inhibitory mechanism of gentamicin in response to electrical field stimulation (EFS) using the rat bladder smooth muscle, atropine or guanethidine was treated but had no effect. Methylsergide, a non-selective 5-HT1, 5-HT2 receptor antagonist was also treated but had on effect. Kinase inhibitors, such as chelerythrine (PKC inhibitor), ML-9 (MLCK inhibitor), or Y27632 (rho kinase inhibitor) were pretreated before gentamicin treatment, but did not have effect. For U73122, a phospholipase C (PLC) inhibitor however, the inhibitory effect to gentamicin was significantly attenuated in all frequencies given by the EFS. Therefore gentamicin induced inhibitory effect on EFS response in rat bladder smooth muscle was not mediated by the activation of adrenergic, cholinergic, or serotonergic receptor. The inhibition of gentamicin might be mediated through the PLC dependent pathway, but not through the PKC, MLCK or rho kinase dependent pathway.

Role of Nicotinic Acetylcholine Receptor α3 and α7 Subunits in Detrusor Overactivity Induced by Partial Bladder Outlet Obstruction in Rats

Purpose:

To investigate the role of α3 and α7 nicotinic acetylcholine receptor subunits (nAChRs) in the bladder, using a rat model with detrusor overactivity induced by partial bladder outlet obstruction (BOO).

Methods:

Forty Sprague-Dawley rats were used: 10 were sham-operated (control group) and 30 were observed for 3 weeks after partial BOO. BOO-induced rats were further divided into 3 groups: Two groups of 10 rats each received intravesicular infusions with hexamethonium (HM group; n=10) or methyllycaconitine (MLC group; n=10), which are antagonists for α3 and α7 nAChRs, respectively. The remaining BOO-induced rats received only saline infusion (BOO group; n=10). Based on the contraction interval measurements using cystometrogram, the contraction pressure and nonvoiding bladder contractions were compared between the control and the three BOO-induced groups. Immunofluorescent staining and Western blotting were used to analyze α3 and α7 nAChRs levels.

Results:

The contraction interval of the MLC group was higher than that of the BOO group (P<0.05). Nonvoiding bladder contraction almost disappeared in the HM and MLC groups. Contraction pressure increased in the BOO group (P<0.05) compared with the control group and decreased in the HM and MLC groups compared with the BOO group (P<0.05). Immunofluorescence staining showed that the α3 nAChR signals increased in the urothelium, and the α7 nAChR signals increased in the urothelium and detrusor muscle of the BOO group compared with the control group. Western blot analysis showed that both α3 and α7 nAChR levels increased in the BOO group (P<0.05).

Conclusions:

Alpha3 and α7 nAChRs are associated with detrusor overactivity induced by BOO. Furthermore, nAChR antagonists could help in clinically improving detrusor overactivity.