Adrenergic relaxations in an in situ urinary bladder model evoked by stimulation of sensory pelvic and pudendal nerves in the rat

Urinary bladder dysfunction might be related to disturbances at different levels of the micturition reflex arc. The current study aimed to further develop and evaluate a split bladder model for detecting and analysing relaxatory signalling in the rat urinary bladder. The model allows for discrimination between effects at the efferent and the afferent side of the innervation. In in vivo experiments, the stimulation at a low frequency (1 Hz) of the ipsilateral pelvic nerve tended to evoke relaxation of the split bladder half (contralateral side; -1.0 ± 0.4 mN; n = 5), in contrast to high frequency-evoked contractions. In preparations in which the contralateral pelvic nerve was cut the relaxation occurred at a wider range of frequencies (0.5-2 Hz). In separate experiments, responses to 1 and 2 Hz were studied before and after intravenous injections of propranolol (1 mg/kg IV). The presence of propranolol significantly shifted the relaxations into contractions. Also, electrical stimulation of the ipsilateral pudendal nerve evoked relaxations of similar magnitude as for the pelvic stimulations, which were also affected by propranolol. In control in vitro experiments, substances with β-adrenoceptor agonism, in contrast to a selective α-agonist, evoked relaxations. The current study shows that the split bladder model can be used for in vivo studies of relaxations. In the model, reflex-evoked sympathetic responses caused relaxations at low intensity stimulation. The involvement of β-adrenoceptors is supported by the sensitivity to propranolol and by the in vitro observations.

Effects of Microbeam Irradiation on Rodent Esophageal Smooth Muscle Contraction

BACKGROUND

High-dose-rate radiotherapy has shown promising results with respect to normal tissue preservation. We developed an ex vivo model to study the physiological effects of experimental radiotherapy in the rodent esophageal smooth muscle.

METHODS

We assessed the physiological parameters of the esophageal function in ex vivo preparations of the proximal, middle, and distal segments in the organ bath. High-dose-rate synchrotron irradiation was conducted using both the microbeam irradiation (MBI) technique with peak doses greater than 200 Gy and broadbeam irradiation (BBI) with doses ranging between 3.5-4 Gy.

RESULTS

Neither MBI nor BBI affected the function of the contractile apparatus. While peak latency and maximal force change were not affected in the BBI group, and no changes were seen in the proximal esophagus segments after MBI, a significant increase in peak latency and a decrease in maximal force change was observed in the middle and distal esophageal segments.

CONCLUSION

No severe changes in physiological parameters of esophageal contraction were determined after high-dose-rate radiotherapy in our model, but our results indicate a delayed esophageal function. From the clinical perspective, the observed increase in peak latency and decreased maximal force change may indicate delayed esophageal transit.

Imatinib Mesylate Reduces Voiding Frequency in Female Mice With Acute Cyclophosphamide-Induced Cystitis

Lamina propria interstitial cells that express the tyrosine kinase receptor, platelet-derived growth factor receptor alpha (PDGFRα) may play a role in urinary sensory signaling. Imatinib mesylate, also referred to as imatinib, is a tyrosine kinase inhibitor that can inhibit PDGFRα and has been widely used in urological research. We evaluated the functional effects of imatinib administration (via oral gavage or intravesical infusion) with two different experimental designs (prevention and treatment), in a cyclophosphamide (CYP)-induced cystitis (acute, intermediate, and chronic), male and female rodent model using conscious cystometry and somatic sensitivity testing. Imatinib significantly (0.0001 ≤ p ≤ 0.05) decreased voiding frequency and increased bladder capacity in acute CYP-induced cystitis, by the prevention (females) and treatment (females and males) designs. Imatinib was not effective in preventing or treating intermediate or chronic CYP-induced cystitis in either sex. Interestingly, in the prevention experiments, imatinib administration increased (0.0001 ≤ p ≤ 0.01) voiding frequency and decreased bladder capacity in control mice. However, in the treatment experiments, imatinib administration decreased (0.01 ≤ p ≤ 0.05) voiding frequency and increased bladder capacity in control mice. Bladder function improvements observed with imatinib treatment in acute CYP-induced cystitis mice remained and additionally improved with a second dose of imatinib 24 hours after CYP treatment. Imatinib administration did not affect pelvic somatic sensitivity in female mice with acute CYP-induced cystitis. Our studies suggest that (1) imatinib improves bladder function in mice with acute CYP-induced cystitis with a prevention and treatment design and (2) interstitial cells may be a useful target to improve bladder function in cystitis.

Imatinib Mesylate Reduces Neurotrophic Factors and pERK and pAKT Expression in Urinary Bladder of Female Mice With Cyclophosphamide-Induced Cystitis

Imatinib mesylate is a tyrosine kinase inhibitor that inhibits platelet-derived growth factor receptor (PDGFR)-α, -β, stem cell factor receptor (c-KIT), and BCR-ABL. PDGFRα is expressed in a subset of interstitial cells in the lamina propria (LP) and detrusor muscle of the urinary bladder. PDGFRα + interstitial cells may contribute to bladder dysfunction conditions such as interstitial cystitis/bladder pain syndrome (IC/BPS) or overactive bladder (OAB). We have previously demonstrated that imatinib prevention via oral gavage or treatment via intravesical infusion improves urinary bladder function in mice with acute (4 hour, h) cyclophosphamide (CYP)-induced cystitis. Here, we investigate potential underlying mechanisms mediating the bladder functional improvement by imatinib using a prevention or treatment experimental design. Using qRT-PCR and ELISAs, we examined inflammatory mediators (NGF, VEGF, BDNF, CCL2, IL-6) previously shown to affect bladder function in CYP-induced cystitis. We also examined the distribution of phosphorylated (p) ERK and pAKT expression in the LP with immunohistochemistry. Imatinib prevention significantly (0.0001 ≤ p ≤ 0.05) reduced expression for all mediators examined except NGF, whereas imatinib treatment was without effect. Imatinib prevention and treatment significantly (0.0001 ≤ p ≤ 0.05) reduced pERK and pAKT expression in the upper LP (U. LP) and deeper LP (D. LP) in female mice with 4 h CYP-induced cystitis. Although we have previously demonstrated that imatinib prevention or treatment improves bladder function in mice with cystitis, the current studies suggest that reductions in inflammatory mediators contribute to prevention benefits of imatinib but not the treatment benefits of imatinib. Differential effects of imatinib prevention or treatment on inflammatory mediators may be influenced by the route and frequency of imatinib administration and may also suggest other mechanisms (e.g., changes in transepithelial resistance of the urothelium) through which imatinib may affect urinary bladder function following CYP-induced cystitis.

Analysis of Clinicopathological Factors Associated with Radiation-Induced Cystitis in Patients with Cervical Cancer

Objective

To analyze the clinicopathological characteristics associated with radiation-induced cystitis (RIC) in patients with cervical cancer treated with chemoradiotherapy (CRT) alone or postoperational (post-op) CRT.

Methods

107 patients with cervical cancer were retrospectively recruited into the study. The surgical status, FIGO staging, total and fractionated doses of radiotherapy (RT), and multiparameters including the dose, volume irradiated to the total bladder, and bladder wall were evaluated for RIC. The criteria on RIC were referred to CTCAE v5.0.

Results

Surgical operation and post-op CRT were delivered in 65 patients and CRT or RT alone in 42 patients. Among those with post-op CRT, 33/34 (97.06%), 22/43 (51.16%), and 10/30 (33.33%) patients were classified as FIGO stage I, II, and III/IV, respectively. The incidence of RIC was 30.84% for the whole group with 87.87% occurred in stage I and II patients. The incidence of CTCAE grade 2 and beyond was significantly higher in patients treated with post-op CRT than those with CRT alone (13.85% vs 2.38%, p = 0.043). Further analyses showed that the CTCAE level of RIC in the post-op CRT group was related to the relatively smaller average bladder volume (p = 0.029), whereas the difference in volume of bladder and bladder wall irradiated to 35.0 Gy or 40.0 Gy was not statistically significant between patients with or without RIC. Conclusion. The combination of surgery and post-op CRT may increase the incidence and severity of radiation-induced cystitis when compared to CRT alone, suggesting that bladder dysfunction associated with surgical procedure might increase the frequency and severity radiation related bladder toxicity. Further study is merited.

Understanding Molecular Mechanisms and Identifying Key Processes in Chronic Radiation Cystitis

Chronic radiation cystitis (CRC) is a consequence of pelvic radiotherapy and affects 5–10% of patients. The pathology of CRC is without curative treatment and is characterized by incontinence, pelvic pain and hematuria, which severely degrades patients’ quality of life. Current management strategies rely primarily on symptomatic measures and have certain limitations. Thanks to a better understanding of the pathophysiology of radiation cystitis, studies targeting key manifestations such as inflammation, neovascularization and cell atrophy have emerged and are promising avenues for future treatment. However, the mechanisms of CRC are still better described in animal models than in human models. Preclinical studies conducted to elucidate the pathophysiology of CRC use distinct models and are most often limited to specific processes, such as fibrosis, vascular damage and inflammation. This review presents a synthesis of experimental studies aimed at improving our understanding of the molecular mechanisms at play and identifying key processes in CRC.

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.

Multicentre International Study for the Prevention with iAluRil of Radio-induced Cystitis (MISTIC): A Randomised Controlled Study

BACKGROUND

Radiation-induced cystitis is a common side effect of radiotherapy (RT) to the pelvic area. Hyaluronic acid (HA) and chondroitin sulfate (CS) are components of the urothelial mucosa and positive results have been obtained for intravesical HA/CS instillations for the treatment of urinary tract infections and bladder pain syndrome. HA/CS may also have a protective effect against RT bladder toxicity.

OBJECTIVE

To investigate whether HA and CS protect the urothelium during RT, alleviate lower urinary tract symptoms, and improve quality of life.

DESIGN SETTING AND PARTICIPANTS

This multicentre randomised controlled trial was conducted across seven centres in four countries. Male patients aged ≥18 yr scheduled to undergo primary intensity-modulated radiotherapy for localised prostate cancer were enrolled.

INTERVENTION

Patients were randomised to intravesical HA/CS plus an oral formulation of curcumin, quercetin, HA, and CS (group A) or no treatment (group B).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was absolute changes from baseline to follow-up in urinary domain scores for the Expanded Prostate Cancer Index Composite (EPIC), the International Consultation on Incontinence Questionnaire-Male Lower Urinary Tract Symptoms (ICIQ-MLUTS), and the EuroQol Group EQ-5D-5L questionnaire. Data analysis for efficacy and safety outcomes was performed using an intention-to-treat (ITT) approach; the ITT population was defined as all randomised patients.

RESULTS AND LIMITATIONS

Of 57 patients screened, 49 were enrolled and randomly assigned to either active treatment (group A, n = 25) or the control (group B, n = 24). Three patients in the control group withdrew after randomisation. Changes from baseline to 12 mo were worse in the control group for subtotal scores for urinary symptoms and impact of symptoms on quality of life and for the total score (p =  0.05, p =  0.003, and p =  0.008, respectively). There was a significant time × group interaction in favour of active treatment for the incontinence symptom score (p =  0.011) and bother score (p =  0.017). The absence of a sham procedure and/or placebo is the main limitation.

CONCLUSIONS

Our results suggest that intravesical HA/CS in combination with an oral formulation may reduce urinary symptoms and improve QoL at short-term (1 yr) follow-up.

PATIENT SUMMARY

We investigated whether hyaluronic acid (HA) and chondroitin sulfate (CS) have a protective effect against the bladder toxicity of radiotherapy for prostate cancer. HA/CS used for weekly bladder irrigation for 6 wk and given orally with curcumin and quercetin for 12 wk reduced urinary incontinence symptoms and bother measured at 1-year follow-up. This may hold promise as a preventive treatment if the results are confirmed in further trials.

Can radiation-induced lower urinary tract disease be ameliorated in patients treated for pelvic organ cancer: ICI-RS 2019?

Aims

This article reviews the clinical outcomes and basic science related to negative effects of radiotherapy (RT) on the lower urinary tract (LUT) when used to treat pelvic malignancies.

Methods

The topic was discussed at the 2019 meeting of the International Consultation on Incontinence―Research Society during a “think tank” session and is summarized in the present article.

Results

RT is associated with adverse effects on the LUT, which may occur during treatment or which can develop over decades posttreatment. Here, we summarize the incidence and extent of clinical symptoms associated with several modes of delivery of RT. RT impact on normal tissues including urethra, bladder, and ureters is discussed, and the underlying biology is examined. We discuss innovative in vivo methodologies to mimic RT in the laboratory and their potential use in the elucidation of mechanisms underlying radiation‐associated pathophysiology. Finally, emerging questions that need to be addressed through further research are proposed.

Conclusions

We conclude that RT‐induced negative effects on the LUT represent a significant clinical problem. Although this has been reduced with improved methods of delivery to spare normal tissue, we need to (a) discover better approaches to protect normal tissue and (b) develop effective treatments to reverse radiation damage.

Radiation of the urinary bladder attenuates the development of lipopolysaccharide-induced cystitis

In the present study we assessed how ionizing radiation affects TLR4-stimulated immune activation in lipopolysaccharide (LPS)-induced cystitis. LPS or saline was administered intravesically to female rats followed by urinary bladder irradiation (20 Gy) 24 h later or sham treatment. Presence in the urinary bladder of inflammatory cells (mast cells, CD3+, ionized calcium-binding adapter molecule 1 (Iba-1)+, CD68+, CD40+, CD80+, CD11c + and CD206 + cells) and expression of oxidative stress (8-OHdG), hypoxia (HIF1α) and anti-oxidative responses (NRF2, HO-1, SOD1, SOD2, catalase) were assessed 14 days later with western blot, qPCR and/or immunohistochemistry. LPS stimulation resulted in a decrease of Iba-1 + cells in the urothelium, an increase in mast cells in the submucosa and a decrease in the bladder protein expression of HO-1, while no changes in the bladder expression of 8-OHdG, NRF2, SOD1, SOD2, catalase and HIF1α were observed. Bladder irradiation inhibited the LPS-driven increase in mast cells and the decrease in Iba1 + cells. Combining LPS and radiation increased the expression of 8-OHdG and number of CD3-positive cells in the urothelium and led to a decrease in NRF2α gene expression in the urinary bladder. In conclusion, irradiation may attenuate LPS-induced immune responses in the urinary bladder but potentiates LPS-induced oxidative stress, which as a consequence may have an impact on the urinary bladder immune sensing of pathogens and danger signals.