Does sheath size matter: benchtop comparison of flow and pressure across variety of continuous flow endoscopes.

INTRODUCTION: Laser enucleation utilizes purpose-built endoscopes for laser stabilization and continuous flow. No evaluation has been done with respect to flow or intravesical pressure with these scopes. We sought to evaluate the effect different endoscopes and sheath sizes on irrigation outflow and intravesical pressure. METHODS: Using a benchtop model using a silicone bladder model, five outer/inner sheath combinations were assessed: Storz 28/26Fr, Storz 26/26Fr, Wolf 26/24Fr, Wolf 26/22Fr, and Wolf 24/22Fr. A urodynamics pressure transducer was inserted alongside the scope for bladder pressure measurement and outflow from scope to drain was measured using uroflowmetry device. Four 1-minute trials were recorded for each sheath and the steady state flow and pressure was recorded. RESULTS: The Storz 28 F outer sheath and 26 F inner sheath had the highest outflow (12.4 ± 0.5 mL/s, p < 0.01). The Wolf 24 F outer and 22 F inner had the lowest outflow (7.0 ± 0.0 mL/s, p < 0.01). The steady state bladder pressure was the lowest in the Storz 28/26 (1.5 ± 1.7 cm H2O, p < 0.01)) and the greatest in the Storz 26/26 (24.2 ± 1.9 cm H2O, p < 0.01). CONCLUSION: The Storz 28/26 combination had best outflow rate and lowest intravesical pressures in our benchtop study. Flow rates generally decreased with smaller sheath sizes and steady state bladder pressures increased as the difference between the outflow and inflow sheath size narrowed. These findings provide initial parameters that could guide sheath selection in future to optimize visualization and success of voiding trials.

Effects of Platelet-Activating Factor (PAF) on the Mechanical Activities of Lower Urinary Tract and Genital Smooth Muscles.

Since its first discovery as a bioactive phospholipid inducing potent platelet aggregation, platelet-activating factor (PAF) has been shown to be involved in a wide variety of inflammatory and allergic disease states. Many pharmacological studies in the 1980s and 1990s also showed that PAF induces endothelium-dependent vascular relaxation and contraction of various smooth muscles (SMs), including those in the airway, gastrointestinal organs, and uterus. However, since the late 1990s, there have been few reports on the SM contractions induced by PAF. The lower urinary tract (LUT), particularly the urinary bladder (UB) has attracted recent attention in SM pharmacology research because patients with LUT dysfunctions including overactive bladder are increasing as the population ages. In addition, recent clinical studies have implicated the substantial role of PAF in the inflammatory state in LUT because its production increases with smoking and with cancer. However, the effects of PAF on mechanical activities of LUT SMs including UBSM have not been investigated to date. Recently, we found that PAF very strongly increased mechanical activities of UBSM in guinea pigs and mice, and partly elucidated the possible mechanisms underlying these actions of PAF. In this review, we describe the effects of PAF on LUT SMs by introducing our recent findings obtained in isolated UBSMs and discuss the physiological and pathophysiological significance. We also introduce our data showing the effects of PAF on the SM mechanical activities of genital tissues (prostate and vas deferens).

Autologous micrografting improves regeneration of tissue-engineered urinary conduits in vivo.

Urogenital reconstructive malformation surgery is sometimes hampered by lack of tissue for the repair. We have previously shown that autologous micrografting allows for single-staged scaffold cellularization after surgical implantation. Here, a collagen-based scaffold reinforced with biodegradable mesh and a stent was implanted as a bladder conduit in ten full-grown female minipigs. We aimed to assess short-term regenerative outcomes, safety, and feasibility of implanting tubular urinary micrografted scaffolds versus acellular controls. Five scaffolds were embedded with autologous urothelial micrografts harvested perioperatively. After six weeks, all animals were assessed by cystoscopy, CT-urography, and microanatomical assessment of the urinary conduits. The procedure proved technically feasible within the confines of a regular surgical theater, with duration-times comparable to corresponding conventional procedures. No animals experienced postoperative complications, and all implanted conduits were patent at follow-up. Improved tissue regeneration was observed in the micrografted conduits compared with the acellular controls, including increased luminal epithelialization, increased cell proliferation, decreased cell apoptosis, and increased conduit vascularization. We concluded that single-staged on-site construction and implantation of tissue engineered urinary conduits proved feasible and safe, with improved regenerative potentials in micrografted conduits. This study presents a new approach to urinary conduits, and merits further investigations for advancement towards clinical translation.

Artificial urinary bladder model.

Technological advancements in the medical field are often slow and expensive, sometimes due to complexities associated with pre-clinical testing of medical devices and implants. There is therefore a growing need for new test beds that can mimic more closely the in vivo environment of physiological systems. In the present study, a novel bladder model was designed and fabricated with the aim of providing a pre-clinical testing platform for urological stents and catheters. The model is collapsible, has a Young's modulus that is comparable to a biological bladder, and can be actuated on-demand to enable voiding. Moreover, the developed fabrication technique provides versatility to adjust the model's shape, size, and thickness, through a rapid and relatively inexpensive process. When compared to a biological bladder, there is a significant difference in compliance; however, the model exhibits cystometry profiles during priming and voiding that are qualitatively comparable to a biological bladder. The developed bladder model has therefore potential for future usage in urological device testing; however, improvements are required to more closely replicate the architecture and relevant flow metrics of a physiological bladder.

Comparison of Wireless Continuous Axillary and Core Temperature Measurement after Major Surgery.

BACKGROUND: Temperature is considered one of the primary vital signs for detection of complications such as infections. Continuous wireless real-time axillary temperature monitoring is technologically feasible at the general ward, but no clinical validation studies exist. METHODS: This study compared axillary temperature with a urinary bladder thermometer in 40 major abdominal postoperative patients. The primary outcome was changes in axillary temperature registrations. Secondary outcomes were mean bias between the urinary bladder and the axillary temperatures. Intermittent frontal and tympanic temperature recordings were also collected. RESULTS: Forty patients were monitored for 50 min with an average core temperature of 36.8 °C. The mean bias was -1.0 °C (LoA -1.9 to -0) after 5 min, and -0.8 °C (LoA -1.6 to -0.1) after 10 min when comparing the axillary temperature with the urinary bladder temperature. After 20 min, the mean bias was -0.6 °C (LoA -1.3-0.1). During upper arm abduction, the axilla temperature was reduced to -1.6 °C (LoA -2.9 to -0.3) within 1 min. Temporal skin temperature measurement had a resulted in a mean bias of -0.1 °C (LOA -1.1 to -1.0) compared with central temperature. Compared with the mean tympanic temperature, it was -0.1 °C (LoA -0.9 to -1.0) lower than the urinay bladder temperature. CONCLUSIONS: Axillary temperature increased with time, reaching a mean bias of 1 °C between axillary and core temperature within 5 min. Opening the axillary resulted in rapidly lower temperature recordings. These findings may aid in use and designing corrections for continuous axillary temperature monitoring.

Assessing the effects of bladder decellularization protocols on extracellular matrix (ECM) structure, mechanics, and biology.

INTRODUCTION: Acellular matrices have historically been applied as biologic scaffolds in surgery, wound care, and tissue engineering, albeit with inconsistent outcomes. One aspect that varies widely between products is the selection of decellularization protocol, yet few studies assess comparative effectiveness of these protocols in preserving mechanics, and protein content. This study characterizes bladder acellular matrix (BAM) using two different detergent and enzymatic protocols, evaluating effects on nuclei and DNA removal (≥90%), structure, tensile properties, and maintenance of extracellular matrix proteins. METHODS: Porcine bladders were decellularized with 0.5% Sodium Dodecyl Sulfate (SDS) or 0.25% Trypsin-hypotonic-Triton X-100 hypertonic (TT)-based agitation protocols, followed by DNase/RNase agents. Characterization of BAM included decellularization efficacy (DAPI, DNA quantification), structure (histology and scanning electron microscopy), tensile testing (Instron 345C-1 mechanical tester), and protein presence and diversity (mass spectrometry). SDS and TT data was directly compared to the same native bladder using two-tailed paired t-tests. Native, TT, and SDS cohorts for tensile testing were compared using one-way ANOVA; Tukey's post-hoc tests for among group differences. RESULTS: Effective nuclei removal was achieved by SDS- and TT-based protocols. However, target DNA removal was achieved with SDS but not TT. SDS more effectively maintained qualitative tissue architecture compared to TT. The tensile modulus of the TT cohort increased, and stretchability decreased after decellularization in both SDS and TT. UTS was unaffected by either protocol. Higher overall diversity and quantity of core matrisome and matrisome-associated proteins was maintained in the SDS vs TT cohort post-decellularization. CONCLUSION: The results indicated that detergent selection affects multiple aspects of the resultant BAM biologic product. In the selected protocols, SDS was superior to TT efficacy, and maintenance of gross tissue architecture as well as maintenance of ECM proteins. Decellularization increased scaffold resistance to deformation in both cohorts. Future studies applying biologic scaffolds must consider the processing method and agents used to ensure that materials selected are optimized for characteristics that will facilitate effective translational use.

Preliminary Experience with Three Alternative Motion Sensors for 0.55 Tesla MR Imaging.

Due to limitations in current motion tracking technologies and increasing interest in alternative sensors for motion tracking both inside and outside the MRI system, in this study we share our preliminary experience with three alternative sensors utilizing diverse technologies and interactions with tissue to monitor motion of the body surface, respiratory-related motion of major organs, and non-respiratory motion of deep-seated organs. These consist of (1) a Pilot-Tone RF transmitter combined with deep learning algorithms for tracking liver motion, (2) a single-channel ultrasound transducer with deep learning for monitoring bladder motion, and (3) a 3D Time-of-Flight camera for observing the motion of the anterior torso surface. Additionally, we demonstrate the capability of these sensors to simultaneously capture motion data outside the MRI environment, which is particularly relevant for procedures like radiation therapy, where motion status could be related to previously characterized cyclical anatomical data. Our findings indicate that the ultrasound sensor can track motion in deep-seated organs (bladder) as well as respiratory-related motion. The Time-of-Flight camera offers ease of interpretation and performs well in detecting surface motion (respiration). The Pilot-Tone demonstrates efficacy in tracking bulk respiratory motion and motion of major organs (liver). Simultaneous use of all three sensors could provide complementary motion information outside the MRI bore, providing potential value for motion tracking during position-sensitive treatments such as radiation therapy.

PTHrP attenuates spontaneous contractions in detrusor smooth muscle of the rat bladder by activating spontaneous transient outward potassium currents.

Parathyroid hormone-related protein (PTHrP) released from detrusor smooth muscle (DSM) cells upon bladder distension attenuates spontaneous phasic contractions (SPCs) in DSM and associated afferent firing to facilitate urine storage. Here, we investigate the mechanisms underlying PTHrP-induced inhibition of SPCs, focusing on large-conductance Ca2+-activated K+ channels (BK channels) that play a central role in stabilizing DSM excitability. Perforated patch-clamp techniques were applied to DSM cells of the rat bladder dispersed using collagenase. Isometric tension changes were recorded from DSM strips, while intracellular Ca2+ dynamics were visualized using Cal520 AM -loaded DSM bundles. DSM cells developed spontaneous transient outward potassium currents (STOCs) arising from the opening of BK channels. PTHrP (10 nM) increased the frequency of STOCs without affecting their amplitude at a holding potential of - 30 mV but not - 40 mV. PTHrP enlarged depolarization-induced, BK-mediated outward currents at membrane potentials positive to + 20 mV in a manner sensitive to iberiotoxin (100 nM), the BK channel blocker. The PTHrP-induced increases in BK currents were also prevented by inhibitors of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) (CPA 10 µM), L-type voltage-dependent Ca2+ channel (LVDCC) (nifedipine 3 µM) or adenylyl cyclase (SQ22536 100 µM). PTHrP had no effect on depolarization-induced LVDCC currents. PTHrP suppressed and slowed SPCs in an iberiotoxin (100 nM)-sensitive manner. PTHrP also reduced the number of Ca2+ spikes during each burst of spontaneous Ca2+ transients. In conclusion, PTHrP accelerates STOCs discharge presumably by facilitating SR Ca2+ release which prematurely terminates Ca2+ transient bursts resulting in the attenuation of SPCs.

Effect of Prewarming on Skin Temperature Changes After Spinal Anesthesia in Transurethral Resection of the Bladder.

PURPOSE: Monitoring of peripheral skin temperature changes is an objective and rapid method to evaluate the success of neuraxial block after spinal anesthesia. The aim of this study is to investigate the effect of prewarming on peripheral temperature changes after the administration of spinal anesthesia. DESIGN: Randomized, prospective, single-blind study. METHODS: In this study, patients scheduled for transurethral resection of the bladder surgery under spinal anesthesia were divided into two groups: those with active prewarming and those without active prewarming. The groups were compared in core and skin temperature changes after administration of spinal anesthesia, length of stay in the postanesthesia care unit, shivering score, and the thermal comfort scale. FINDINGS: A statistically significant difference was found between the groups on time for a 1 °C increase in ankle and toe skin temperatures (P < .001). There was a statistically significant difference between the groups in core temperature measurements (P < .001). When thermal comfort was compared between the groups, a statistically significant difference was found (P < .001). Patients' shivering score (P = .704), and length of stay in the postanesthesia care unit (P = .059) between the groups were similar. CONCLUSIONS: Skin temperature changes in the prewarming group were lower, and this group had a lower rate of increase than the nonprewarming group. Therefore, skin temperature changes in the lower extremity can be used to determine the success of spinal anesthesia in patients who are prewarmed, with the awareness of these differences.

Vagal afferent responses to cystometry in rat models of urinary bladder irritation: c-fos immunohistochemistry study.

PURPOSE: Although recent literature provides increasing evidence concerning urinary bladder innervation by vagal afferents, the functional aspects and the conditions at which these afferents are recruited are still unclear. METHODS: In the present study, the neuronal responses of nodose ganglion following cystometry, under different models of rat's urinary bladder irritation, cyclophosphamide (CYP), cyclophosphamide with cervical vagotomy (Vx), chronic HCl, and acute HCl, were investigated using c-fos immunohistochemistry. RESULTS: The c-fos expression in the nodose ganglion, following cystometry, was increased significantly in the CYP and chronic-HCl groups compared to the intact, Vx, and acute-HCl groups. In addition, the acute-HCl group showed a significant increase compared to intact animals. Following cervical vagotomy, the expression in the Vx group decreased significantly compared to the CYP group, but was significantly higher than that in the intact group. CONCLUSION: The results of this study demonstrate the innervation of the vagus afferents to the urinary bladder. This innervation is activated under urinary bladder irritation conditions, which may indicate a possible role of the vagus nerve during urinary bladder pathology.

H2O2 enhances the spontaneous phasic contractions of isolated human-bladder strips via activation of TRPA1 channels on sensory nerves and the release of substance P and PGE2.

Several studies have indicated that reactive oxygen species (ROS) can lead to detrusor overactivity (DO), but the underlying mechanisms are not known. Hydrogen dioxide (H2O2) is used commonly to investigate the effects of ROS. In present study, we investigated the effects of H2O2 on phasic spontaneous bladder contractions (SBCs) of isolated human-bladder strips (iHBSs) and the underlying mechanisms. Samples of bladder tissue were obtained from 26 patients undergoing cystectomy owing to bladder cancer. SBCs of iHBSs were recorded in organ-bath experiments. H2O2 (1µM-10mM) concentration-dependently increased the SBCs of iHBSs. These enhancing effects could be mimicked by an agonist of transient receptor potential (TRP)A1 channels (allyl isothiocyanate) and blocked with an antagonist of TRPA1 channels (HC030031; 10 µM). H2O2 induced enhancing effects also could be attenuated by desensitizing sensory afferents with capsaicin (10 µM), blocking nerve firing with TTX (1 µM), blocking neurokinin effects with NK2 receptor antagonist (SR48968, 10 µM), and blocking PGE2 synthesis with indomethacin (10 µM), respectively. Our study: (i) suggests activation of TRPA1 channels on bladder sensory afferents, and then release of substance P or PGE2 from sensory nerve terminals, contribute to the H2O2-induced enhancing effects on SBCs of iHBSs; (ii) provides insights for the mechanisms underlying ROS leading to DO; (iii) indicates that targeting TRPA1 channels might be the promising strategy against overactive bladder in conditions associated with excessive production of ROS.

[Analysis of surgical complications of reconstructive plastic surgery according to the ClavienDindo classification].

INTRODUCTION: The systematization of surgical complications has long been a serious problem since different types of surgical procedures have specific complications, in addition to general consequences. Created in 1992 and improved in 2004, the Clavien-Dindo classification was successfully validated in surgical centers in different countries and recognized as an important tool for the qualitative assessment of surgical complications. AIM: To improve reconstructive procedures by systematizing complications based on the ClavienDindo classification. MATERIALS AND METHODS: The results of substitution ileocystoplasty in 95 patients with contracted bladder due to tuberculosis and other diseases are presented. In 50 (52.6%) cases, the length of the bowel segment was 30-35 cm (group 1, main), while in 45 patients (47.4%) a segment of 45-60 cm was chosen (group 2, control). RESULTS: Early complications of grade II developed in 11 (22.0%) patients in the group 1 and in 13 (28.9%) in group 2, while grade III in 5 (10.0%) and 6 (13.3%) cases, respectively. Complications of IIIb grade were seen among patients of the main group in 9 (18.0%) cases compared to 12 (26.7%) in the control group. Severe complications of IVa and IVb grades were documented with the same frequency in both groups, in one case each. Complications of V grade (death) were recorded only in the group 2. Late complications were registered in 63 out of 94 patients. In group 1, there were 26 complications (16 somatic and 10 surgical), while in group 2, a total of 37 complications (24 somatic and 13 surgical) were seen, which indicates a significant higher rate in the control group (p<0.05). In group 1, transurethral resection of urethral-enteric anastomosis and ureteral reimplantation were performed less frequently than in group 2, while transurethral resection of the prostate was done with the same frequency. At the same time, percutaneous nephrostomy was required more often in the group 1 (6% vs. 4.5% in the group 2). After intestinal cystoplasty with a shortened fragment of the ileum, the voiding volume was significantly lower but corresponded to the physiological value (more than 150 ml). In this group, there was sufficient capacity of neobladder with a minimum amount of residual urine, effective emptying, satisfactory urinary continence, and low intraluminal pressure, which contributes to the protection of kidneys from reservoir-ureteral-pelvic reflux. The serum chloride level after surgery was 106.2+/-0.4 in the group 1 compared to 109.7+/-0.3 in the group 2, while base excess was -0.93+/-0.3 and -3.4+/-0.65, respectively (p<0.05). CONCLUSION: Early serious postoperative complications according to Clavien-Dindo were registered with approximately the same frequency in both groups, while late complications developed significantly more often in the group 2. The urodynamic parameters of a neobladder formed from ileum segment of 30-35 cm are satisfactory. In addition, a decrease in the length of the intestinal segment prevents the development of hyperchloremic metabolic acidosis.

In Vivo Luminal Measurement of Distension-evoked Urothelial ATP Release in Rodents.

ATP, released from the urothelium in response to bladder distension, is thought to play a significant sensory role in the control of micturition. Therefore, accurate measurement of urothelial ATP release in a physiological setting is an important first step in studying the mechanisms that control purinergic signaling in the urinary bladder. Existing techniques to study mechanically evoked urothelial ATP release utilize cultured cells plated on flexible supports or bladder tissue pinned into Ussing chambers; however, each of these techniques does not fully emulate conditions in the intact bladder. Therefore, an experimental setup was developed to directly measure ATP concentrations in the lumen of the rodent urinary bladder. In this setup, the bladders of anesthetized rodents are perfused through catheters in both the dome of the bladder and via the external urethral orifice. Pressure in the bladder is increased by capping the urethral catheter while perfusing sterile fluid into the bladder through the dome. Measurement of intravesical pressure is achieved using a pressure transducer attached to the bladder dome catheter, akin to the setup used for cystometry. Once the desired pressure is reached, the urethral catheter's cap is removed, and fluid collected for ATP quantification by luciferin-luciferase assay. Through this experimental setup, the mechanisms controlling both mechanical and chemical stimulation of urothelial ATP release can be interrogated by including various agonists or antagonists into the perfusate or by comparing results between wildtype and genetically modified animals.

Closed-loop sacral neuromodulation for bladder function using dorsal root ganglia sensory feedback in an anesthetized feline model.

Overactive bladder patients suffer from a frequent, uncontrollable urge to urinate, which can lead to a poor quality of life. We aim to improve open-loop sacral neuromodulation therapy by developing a conditional stimulation paradigm using neural recordings from dorsal root ganglia (DRG) as sensory feedback. Experiments were performed in 5 anesthetized felines. We implemented a Kalman filter-based algorithm to estimate the bladder pressure in real-time using sacral-level DRG neural recordings and initiated sacral root electrical stimulation when the algorithm detected an increase in bladder pressure. Closed-loop neuromodulation was performed during continuous cystometry and compared to bladder fills with continuous and no stimulation. Overall, closed-loop stimulation increased bladder capacity by 13.8% over no stimulation (p < 0.001) and reduced stimulation time versus continuous stimulation by 57.7%. High-confidence bladder single units had a reduced sensitivity during stimulation, with lower linear trendline fits and higher pressure thresholds for firing observed during stimulation trials. This study demonstrates the utility of decoding bladder pressure from neural activity for closed-loop control of sacral neuromodulation. An underlying mechanism for sacral neuromodulation may be a reduction in bladder sensory neuron activity during stimulation. Real-time validation during behavioral studies is necessary prior to clinical translation of closed-loop sacral neuromodulation.

Urinary Exosomal Long Noncoding RNA TERC as a Noninvasive Diagnostic and Prognostic Biomarker for Bladder Urothelial Carcinoma.

PURPOSE: Bladder cancer is one of the most common urological malignancies worldwide, and approximately 90% of bladder cancer cases are histologically typed as bladder urothelial carcinoma (BLCA). Exosomes are 30 to 200 nm extracellular vesicles that transport microRNAs, long noncoding RNAs (lncRNAs), mRNAs, circular RNAs, and proteins across tissues and through circulation. Urinary exosomes may contain genetic information from tumor cells. Herein, we explored the clinical significance of urinary exosomal lncRNA telomerase RNA component (TERC) levels to provide an urgently needed diagnostic and prognostic biomarker for BLCA. MATERIALS AND METHODS: In this study, we used RNA-sequencing of samples from four BLCA patients and three healthy controls to identify that TERC was differentially expressed in urinary exosomes. We then used quantitative PCR in different types of clinical samples to validate the biomarker and analyzed results using receiver operating characteristic curves. RESULTS: We found that TERC was significantly upregulated in urinary exosomes from BLCA patients compared with those from healthy controls (P < 0.0001). Urinary exosomal TERC showed higher sensitivity (78.65%) and accuracy (77.78%) than existing indicators including nuclear matrix protein-22 and urine cytometry. Using the cut-off value 4.302, the area under the curve for urinary exosomal TERC was 0.836 (95% confidence interval: 0.768-0.891, P < 0.0001). Furthermore, this noninvasive assay could distinguish low-grade and high-grade tumors (P = 0.0153). CONCLUSIONS: TERC is enriched in urinary exosomes from BLCA patients. Urinary exosomal TERC could become a diagnostic and prognostic biomarker for BLCA that allows clinicians to realize noninvasive detection of BLCA.

[Pilot study of the manifestations of synchrony of the anatomical-metabolic and functional state of the brain, kidneys and bladder].

im. The results of clinical observations and scientific studies of recent years indicate that abstinence from urination before the introduction of radiopharmaceuticals for PET / CT procedures is accompanied by a significantly lower flow of it into the bladder than after preliminary urination. PURPOSE OF THE STUDY: Comparative analysis of PET/CT metabolism of 18F-fluorodeoxyglucose at the level of the cingulate gyrus of the brain, different regions of the kidney parenchyma and in the bladder wall in individuals without nephrourological history, depending on the phase of the functional state of the bladder. MATERIALS AND METHODS: The results of PET/CT of the whole body of 30 patients of the radiological center of the Tyumen Regional Oncological Dispensary, including 16 men and 14 women (median age 52.5 (38; 63) years), were analyzed, distributed randomly in three equal study groups: after urination, in the intermictory period and immediately after the appearance of the first urge to urinate. RESULTS: Signs of synchrony were revealed in the anatomical and metabolic activity of the cortical vegetative centers, certain regions of the renal parenchyma and the wall of the bladder in the process of urination, the movement of urine along the urinary tract, the stage of its accumulation in the bladder and preparation for urination. CONCLUSION: The data obtained allow us to assume that the analyzed regions are equivalent areas of the general regulatory system that provides physiological processes in the organs of the urinary system. However, this fact requires further research and clarification.

Regeneration of muscular wall of the bladder using a ureter matrix graft as a scaffold.

We investigated a method for bladder augmentation in rats using a decellularized ureter graft. We used 16 rats divided into two groups of eight. After partial cystectomy, the bladders in group 1 were grafted with a 1 cm2 patch of human decellularized ureter. Rats in group 2 were untreated controls. Biopsies of the graft were taken at 1, 3 and 9 months postoperatively for histological investigation. Total removal of cells and preservation of extracellular matrix (ECM) was confirmed in the decellularized ureter. Histological examination after 1 month revealed few cells at the border of the graft. Three months after the operation, the graft was infiltrated by vessels and smooth muscle and the mucosal lining was complete. All bladder wall components resembled native bladder wall by 9 months after implantation. CD34, CD31, α-smooth muscle actin, S100, cytokeratin AE1/AE3 and vimentin were detected 9 months after the operation. We demonstrated the potential of decellularized biocompatible ureteric grafts for use as a natural collagen scaffold for bladder repair in rats.

Lower urinary tract electrical sensory assessment: a systematic review and meta-analysis.

OBJECTIVES: To summarize the current literature on lower urinary tract electrical sensory assessment (LUTESA), with regard to current perception thresholds (CPTs) and sensory evoked potentials (SEPs), and to discuss the applied methods in terms of technical aspects, confounding factors, and potential for lower urinary tract (LUT) diagnostics. METHODS: The review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Medline (PubMed), Embase and Scopus were searched on 13 October 2020. Meta-analyses were performed and methodological qualities of the included studies were defined by assessing risk of bias (RoB) as well as confounding. RESULTS: After screening 9925 articles, 80 studies (five randomized controlled trials [RCTs] and 75 non-RCTs) were included, comprising a total of 3732 patients and 692 healthy subjects (HS). Of these studies, 61 investigated CPTs exclusively and 19 reported on SEPs, with or without corresponding CPTs. The recording of LUTCPTs and SEPs was shown to represent a safe and reliable assessment of LUT afferent nerve function in HS and patients. LUTESA demonstrated significant differences in LUT sensitivity between HS and neurological patients, as well as after interventions such as pelvic surgery or drug treatments. Pooled analyses showed that several stimulation variables (e.g. stimulation frequency, location) as well as patient characteristics might affect the main outcome measures of LUTESA (CPTs, SEP latencies, peak-to-peak amplitudes, responder rate). RoB and confounding was high in most studies. CONCLUSIONS: Preliminary data show that CPT and SEP recordings are valuable tools to more objectively assess LUT afferent nerve function. LUTESA complements already established diagnostics such as urodynamics, allowing a more comprehensive patient evaluation. The high RoB and confounding rate was related to inconsistency and inaccuracy in reporting rather than the technique itself. LUTESA standardization and well-designed RCTs are crucial to implement LUTESA as a clinical assessment tool.

The Significance of Biomechanics and Scaffold Structure for Bladder Tissue Engineering.

Current approaches for bladder reconstruction surgery are associated with many morbidities. Tissue engineering is considered an ideal approach to create constructs capable of restoring the function of the bladder wall. However, many constructs to date have failed to create a sufficient improvement in bladder capacity due to insufficient neobladder compliance. This review evaluates the biomechanical properties of the bladder wall and how the current reconstructive materials aim to meet this need. To date, limited data from mechanical testing and tissue anisotropy make it challenging to reach a consensus on the native properties of the bladder wall. Many of the materials whose mechanical properties have been quantified do not fall within the range of mechanical properties measured for native bladder wall tissue. Many promising new materials have yet to be mechanically quantified, which makes it difficult to ascertain their likely effectiveness. The impact of scaffold structures and the long-term effect of implanting these materials on their inherent mechanical properties are areas yet to be widely investigated that could provide important insight into the likely longevity of the neobladder construct. In conclusion, there are many opportunities for further investigation into novel materials for bladder reconstruction. Currently, the field would benefit from a consensus on the target values of key mechanical parameters for bladder wall scaffolds.