Implications of the COVID19 pandemic on the need and timing of second transurethral bladder tumour resection in high-grade non-muscle invasive bladder cancer.

PURPOSE: Due to the COVID19 pandemic, the EAU has recommended to, if needed, postpone second transurethral resection of bladder tumour (TURBT) after BCG induction in selected patients. We aimed to evaluate the oncological outcomes of postponed TURBT and the potential to replace second TURBT by routine cystoscopy and cytology. METHODS: A single-center, retrospective analysis of patients with TaG3/high grade (HG) or T1HG urothelial bladder cancer was performed. All patients underwent a complete TURBT between 2000 and 2013 with presence of detrusor muscle, full BCG induction and routine cystoscopy and cytology, followed by a second TURBT. Results of the cystoscopy, cytology and pathology reports of the TURBT were analyzed by descriptive characteristics, sensitivity, specificity, negative and positive predictive values, as well as survival analyses. RESULTS: 112 patients were included. Residual tumour was present at second TURBT in 21.4%. Upstaging rate from pTaHG to pT1HG and pT1HG to pT2 was 0% and 2.7%, respectively. pT0 was confirmed in 79% of patients, but in 98% of patients with combined negative cytology and cystoscopy after BCG. With a median follow-up of 109 months, the 3-year OS was 85%, RFS 74% and PFS 89%. Sensitivity, specificity, negative predictive value and positive predictive value of cystoscopy and urinary cytology for the presence of residual tumour were 92%, 97%, 98% and 85%, respectively. CONCLUSION: This study underpins the recommendation of the EAU NMIBC guideline panel that, if needed and in selected patients, second TURBT may be postponed until after BCG induction treatment in pT1HG disease. Also, routine second TURBT can be omitted in pTaHG disease. Data on replacing second TURBT after BCG treatment by routine cystoscopy and cytology appear promising but require further confirmation in prospective studies.

Longitudinal Follow-Up of Urinary Tract Infections and Their Treatment in Mice using Bioluminescence Imaging.

Urinary tract infections (UTI) rank among the most common bacterial infections in humans and are routinely treated with empirical antibiotics. However, due to increasing microbial resistance, the efficacy of the most used antibiotics has declined. To find alternative treatment options, there is a great need for a better understanding of the UTI pathogenesis and the mechanisms that determine UTI susceptibility. In order to investigate this in an animal model, a reproducible, non-invasive assay to study the course of UTI is indispensable. For years, the gold standard for the enumeration of bacterial load has been the determination of Colony Forming Units (CFU) for a particular sample volume. This technique requires post-mortem organ homogenates and serial dilutions, limiting data output and reproducibility. As an alternative, bioluminescence imaging (BLI) is gaining popularity to determine the bacterial load. Labeling pathogens with a lux operon allow for the sensitive detection and quantification in a non-invasive manner, thereby enabling longitudinal follow-up. So far, the adoption of BLI in UTI research remains limited. This manuscript describes the practical implementation of BLI in a mouse urinary tract infection model. Here, a step-by-step guide for culturing bacteria, intravesical instillation and imaging is provided. The in vivo correlation with CFU is examined and a proof-of-concept is provided by comparing the bacterial load of untreated infected animals with antibiotic-treated animals. Furthermore, the advantages, limitations, and considerations specific to the implementation of BLI in an in vivo UTI model are discussed. The implementation of BLI in the UTI research field will greatly facilitate research on the pathogenesis of UTI and the discovery of new ways to prevent and treat UTI.

Transient receptor potential channels in sensory mechanisms of the lower urinary tract.

Disruptions to sensory pathways in the lower urinary tract commonly occur and can give rise to lower urinary tract symptoms (LUTS). The unmet clinical need for treatment of LUTS has stimulated research into the molecular mechanisms that underlie neuronal control of the bladder and transient receptor potential (TRP) channels have emerged as key regulators of the sensory processes that regulate bladder function. TRP channels function as molecular sensors in urothelial cells and afferent nerve fibres and can be considered the origin of bladder sensations. TRP channels in the lower urinary tract contribute to the generation of normal and abnormal bladder sensations through a variety of mechanisms, and have demonstrated potential as targets for the treatment of LUTS in functional disorders of the lower urinary tract.

TRPM3 Is Expressed in Afferent Bladder Neurons and Is Upregulated during Bladder Inflammation.

The cation channel TRPM3 is activated by heat and the neurosteroid pregnenolone sulfate. TRPM3 is expressed on sensory neurons innervating the skin, where together with TRPV1 and TRPA1, it functions as one of three redundant sensors of acute heat. Moreover, functional upregulation of TRPM3 during inflammation contributes to heat hyperalgesia. The role of TRPM3 in sensory neurons innervating internal organs such as the bladder is currently unclear. Here, using retrograde labeling and single-molecule fluorescent RNA in situ hybridization, we demonstrate expression of mRNA encoding TRPM3 in a large subset of dorsal root ganglion (DRG) neurons innervating the mouse bladder, and confirm TRPM3 channel functionality in these neurons using Fura-2-based calcium imaging. After induction of cystitis by injection of cyclophosphamide, we observed a robust increase of the functional responses to agonists of TRPM3, TRPV1, and TRPA1 in bladder-innervating DRG neurons. Cystometry and voided spot analysis in control and cyclophosphamide-treated animals did not reveal differences between wild type and TRPM3-deficient mice, indicating that TRPM3 is not critical for normal voiding. We conclude that TRPM3 is functionally expressed in a large proportion of sensory bladder afferent, but its role in bladder sensation remains to be established.

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

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