Abstracts of the 40th World Congress of Endourology: WCE 2023

Journal of EndourologyVol. 37, No. S1 AbstractsFree AccessAbstracts of the 40th World Congress of Endourology: WCE 2023Published Online:27 Sep 2023https://doi.org/10.1089/end.2023.36001.abstractsAboutSectionsPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail BASIC SCIENCE POSTER SESSION 1: MISCELLANEOUSBS01‐01 Single Cell Transcriptional Profiles of Benign Prostatic HyperplasiaRei Unno2, Heiko Yang1, Kazumi Taguchi2, Shuzo Hamamoto2, Atsushi Okada2, Takahiro Yasui2, Thomas Chi1, Franklin Huang11Department of Urology, University of California, San Francisco, 2Department of Nephro‐urology, Nagoya City University Graduate School of Medical SciencesPresented By: Rei Unno, MD, PhDIntroduction: Benign prostatic hyperplasia (BPH) affects the majority of aging men and leads to lower urinary tract symptoms. Based on histological characteristics and bulk sequencing data, the pathophysiology and underlying mechanisms of BPH are poorly understood. The aim of this study was to investigate the transcriptional profile of BPH at single cell resolution to improve our understanding of the molecular features of BPH.Methods: Fifteen BPH specimens were collected from patients undergoing holmium laser enucleation of the prostate. Cells from each specimen were isolated, captured, and sequenced using a bead‐based single‐cell RNA sequencing platform (Seq‐well). Transcriptomic analysis of the gene expression matrices was performed. The absence of malignant pathologic diagnoses was independently confirmed.Results: 16,234 cells from 15 BPH specimens were analyzed. By canonical cell type markers, we annotated three major cell types (epithelial, stromal, and immune cells). Using significantly upregulated genes in BPH compared to normal prostates previously derived from a bulk RNA sequencing comparison, bulk sequencing highlighted only the fibroblast populations. After performing a sub‐clustering analysis of the 6249 epithelial cells, we identified four luminal cell subclusters showing similar levels of luminal epithelial markers KLK3, KLK2, and NKX3‐1, as well as one distinct basal and one club cell population. Analysis of the differentially expressed genes among the four luminal subclusters revealed that luminal subcluster 4 was enriched in a specific signature gene set, including ribosomal genes and KLK4, which has been shown to be abundant in BPH, compared to the other subclusters. Gene ontology analysis using this gene set demonstrated that luminal subcluster 4 was associated with pathways such as oxidative phosphorylation and adipogenesis. Analyses of the BPH immune microenvironment showed a larger proportion of pro‐inflammatory cells, such as M1 macrophages, compared to anti‐inflammatory cells within the myeloid cell population.Conclusions: Single cell profiling identified epithelial cells, stromal cells, and immune cells. We confirmed the upregulation of previously derived BPH‐associated genes in the fibroblast population and the enrichment of pro‐inflammatory myeloid cells in the immune microenvironment. Within the epithelial cell population, we identified a luminal epithelial subcluster that may represent a cell state associated with BPH.Funding: NoneBS01‐02 MBD2 Promotes Bladder Fibrosis Via Macrophage‐Myofibroblast TransitionWei Wang1, Lede Lin1, Huiling Chen1, Liang Zhou11Department of Urology, Institute of Urology (Laboratory of Reconstructive Urology), West China Hospital, Sichuan University, Chengdu, Sichuan, P.R. ChinaPresented By: Wei Wang, MDIntroduction: Unresolved inflammation can lead to tissue fibrosis and impaired organ function. Macrophage–myofibroblast transition (MMT) is one newly identified process to generate collagen‐producing myofibroblasts in fibrotic disease. However, the mechanisms underlying MMT remain to be determined. Here, we investigated the potential role of methyl‐CpG binding domain 2 (MBD2)‐mediated MMT in bladder fibrosis with bladder outlet obstruction (BOO) mice.Methods: Male C57BL/6 mice were subjected to a surgical operation for BOO as previously reported. Bladder tissues were harvested for assays of flow cytometry, western blot, histological examinations, immunohistochemistry staining and immunofluorescence. In vitro, bone marrow‐derived macrophages (BMDM) were isolated from mice by flushing the femur and tibia with DMEM/F12 medium, dispersing the cells and isolating F4/80+ cells via FACS (> 99% purity). Generation of MMT cells from BMDMs was stimulated by TGF‐β1 as described previously.Results: The expression of MBD2 was abnormally increased in the BOO group, accompanied by MMT cell accumulation. Interestingly, we found that MBD2 was highly expressed by macrophages undergoing MMT in sites of bladder fibrosis. In vitro study demonstrated that TGF‐β1 treatment significantly upregulated the expression of collagen‐1, fibronectin, α‐smooth muscle actin and MBD‐2 in macrophages. Furthermore, systemic knockout of MBD2 alleviated bladder fibrosis and pathological damage. MBD2 deficiency significantly attenuated MMT cell infiltration in the bladder following BOO induction.Conclusions: Our findings establish a role for MBD2 in MMT and bladder fibrosis and suggest that MBD2 may be a therapeutic target for BOO with progressive bladder fibrosis.Funding: This study was supported by the National Natural Science Foundation of China (Grant No. 81800667, 82270811), and the Project of Science and Technology Department of Sichuan Province (Grant No. 22NSFSC1447).BS01‐03 Associations Between the Prostatic Microbiome and Prostate Size in BPHAaron Miller2, Alec Sun1, Prajit Khooblall2, Juan Sebastián Rodriquez Alvarez2, Smita De21Case Western Reserve University School of Medicine, 2Cleveland ClinicPresented By: Aaron Miller, PhDIntroduction: Though benign prostatic hyperplasia (BPH) affects an estimated 70% of men between the ages of 60‐69, the etiology is not well understood. Recently, the human urinary tract microbiome has been associated with a variety of urologic diseases, especially those mediated by an inflammatory pathway. Here, we sought to determine associations between age‐independent prostate size and microbiome.Methods: Men over 18 years old undergoing Holmium Laser Enucleation of the Prostate (HoLEP) for BPH were recruited if they had no history of prostate cancer, prostate surgery, or pelvic radiation. Patients were excluded if they had a positive preprocedural urine culture, recent UTI requiring antibiotics, bladder stones, or if they were catheter‐dependent due to obstruction. Prostate tissue samples, catheterized urine, and urethral and specimen container swabs were collected from each patient. All non‐prostate samples were used as contamination controls. Patient data such as age, prostate‐specific antigen (PSA) level, BPH symptoms, and prostate size were recorded. All samples underwent DNA extraction, 16S sequencing, and analysis in R statistical software. After quality control, reads associated with the controls were removed. High‐quality, decontaminated data were assessed for diversity (alpha, beta, taxonomy). The correlation between amplicon sequence variants (ASVs) and patient metrics were quantified through Sparcc correlations, which was designed for count matrix correlations.Results: 20 patients qualified, consented, and were analyzed in this study. Mean age, PSA, and prostate size were 68.6 years, 3.4 ng/mL, and 107.9 g, respectively. After bioinformatic decontamination of samples with the negative controls, diversity analyses identified distinct microbiomes: site‐specific differences between the urine, urethral swab, and prostate microbiomes were greater than inter‐individual variability. Common uropathogens were positively associated with prostate size. These included five ASVs belonging to Enterobacter cloaceae (p = 0.02‐0.03), four Planococcaceae ASVs (p = 0.008‐0.03), and four Acinetobacter (p = 0.014‐0.026). Only one ASV in the Ralstonia genus exhibited a significant association with age (p = 0.015).Conclusions: This study is the first to characterize the prostatic microbiome in BPH and to link prostate size to specific common bacterial uropathogens, while controlling for age and contamination. Further research with a larger sample size and culturomics will provide insight into the mechanisms of how the prostate microbiome contributes to enlarged size.Funding: Endourological Society Summer Student ScholarshipBS01‐04 WITHDRAWNBS01‐05 Toward Ultrasound‐Guided Trans‐Perineal High Intensity Focused Ultrasound Treatment of Benign Prostatic Hyperplasia Pre‐Clinical ValidationEhud Willenz4, Gilad Segev1, Yoni Hertzberg2, Alex Volovick2, Shmuel Ben‐Ezra2, Doron Kopelman31Hebrew University, 2NINA Medical, 3Technion, Israel Institute of Technology, 4Shamir Medical CenterPresented By: Ehud Willenz, DVMIntroduction: The trans‐perineal (TP) approach to the prostate for Ultrasound (US) imaging and for focal therapy using High Intensity Focused Ultrasound (HIFU)offers several advantages over alternatives. TP US‐ guided HIFU could become a completely non‐invasive treatment for Benign Prostatic Hyperplasia (BPH), in contrast to the existing minimally invasive ones.We present the results of pre‐clinical studies demonstrating US‐guided HIFU ablation with real‐time tracking of the focal point prior to and during the ablation process.During pre‐clinical phase of the TP US‐guided HIFU ablation system, experimental treatment was suggested to dog owners for dogs diagnosed with prostate cancer. Prior to dog treatment, a safety in‐vivo experiment was performed ina pig model.Methods: NINA Medical's (Nazareth, Israel) HIFU system was used for the ablation. The pre‐clinical safety experiments were approved by local Helsinki committee 14/2020 (Shamir Medical Center) and experimental treatments for dogs were approved by local Helsinki committee MD‐21‐16565‐3 (Hebrew University). Two treatment attempts were applied to two different dogs. Figure depicts the HIFU beam visualization as was observed in‐situ (pig's thigh) in real‐time with schematic drawings of the system location.During sonication, a fused display of the anatomy and HIFU imaging is presented to the physician. (1) schematics of transducer location on the skin, (2) a water balloon coupled to the skin, (3) the skin interface, (4) real‐time visualization of the focal point.Results: Four different lesions were created in pig's thigh during the safety experiment, using various HIFU parameters, under US guidance.During treatment, dogs were under general anesthesia, and the prostate was approached via the abdomen due to the lack of substantial perineum. The prostate capsule, the urethra (catheterized) and the HIFU beam were observed with US, including US imaging of the focal point within the prostate.No skin burns or any damage to the surrounding tissue including the urethra was observed following the treatments.Conclusions: New HIFU imaging technology provides real‐time feedback from the focal point within the body prior to and during ablation, paving the way for TP non‐invasive treatment of BPH.Funding: NINA Medical Ltd.BS01‐06 Analysis of the Top‐Down HoLEP Learning Curve: A Single‐Centre Experience of Two Clinical FellowsHusain Alaradi1, Hazem Elmansy1, Abdulrahman Alkandari1, Moustafa Fathy1, Parsa Nikoufar1, Loay Abbas1, Prashidhi Pathak1, Amr Hodhod1, Walid Shahrour11Northern Ontario School of MedicinePresented By: Sai Vangala, MDIntroduction: Holmium laser enucleation of the prostate (HoLEP) is known to have a steep learning curve. The top‐down technique was introduced to lessen the number of procedures required to master HoLEP. The objective of our study was to present the experiences of two successive clinical fellows with the top‐down HoLEP learning curve and to compare the fellows' performance with their supervisor.Methods: We conducted a prospective study of 40 patients that underwent top‐down HoLEP performed by two successive clinical fellows at our institution from September 2020 to July 2022. Prior to data collection, each fellow observed three top‐down HoLEP procedures and assisted with seven additional cases before independently performing top‐down HoLEP under supervision. We collected data from each fellow's first 20 consecutive top‐down HoLEP procedures. All patients included in the study had a prostate size > 80 g. The learners' cases were grouped according to chronological order (Cases 1‐10 and 11‐20). The primary outcome was defined as the number of cases before the clinical fellow could independently complete all steps of top‐ down HoLEP without any major intraoperative complications. The secondary outcomes included the intraoperative and postoperative outcomes of both groups. The 40 cumulative cases of the clinical fellows were then compared to 148 procedures performed by their supervisor in terms of efficiency, outcomes, and complications.Results: There were no significant differences in baseline patient demographics for both clinical fellows. Each learner performed the first 20 cases independently without needing the supervisor to intervene. There were no major intraoperative complications recorded and no statistically significant differences in intraoperative and postoperative outcomes between fellows' cases (Table 1). There was a statistically significant difference between the fellows and their supervisor in terms of operative efficiency and enucleation efficiency (p = 0.000). We did not find a significant difference between the fellows and the supervisor regarding intraoperative complications, major postoperative complications, or postoperative subjective and objective parameters.Conclusions: Top‐down HoLEP shows promising and reproducible results in shortening the HoLEP learning curve. Further comparative and multi‐institutional studies with additional learners are needed to verify our preliminary findings.Funding: NoneBS01‐07 Initial Experience of Smart Phone Based AI Generated Uroflowmetry in Post‐HOLEP PatientsJames Johannes1, Alexis Brown1, Jaylon Hartley11Lehigh Valley Health NetworkPresented By: james johannes, MDIntroduction: Remote medical monitoring and testing is rapidly developing due to medical access challenges and emphasis on value based care. We tested a novel machine learning based smartphone app for following post‐HOLEP patients uroflowmetry and IPSS.Methods: Patients within the first year of HOLEP recovery performed at home uroflowmetry using the Emano Flo app (EF). These results were compared to digital weight sensor uroflowmetry in the office.EF is a smartphone based app using AI to generate a flow curve based on acoustics of a urine stream contacting the toilet bowl water. Prior to voiding into a toilet, the patient opens the app on his phone and presses record. The phone is placed on any surface. After the void is complete, the patient answers standard IPSS questions. Data is accumulated over a 7‐10 day period of voids, aggregated, and reported to the ordering physician.Results: 11 patients underwent both in‐office uroflowmetry/PVR/IPSS and remote EF. 8 patients performed at the 1 month post‐op visit, 3 at 3 months, 1 at 12 months postop. Results are in Table 1. Patients performing the EF averaged 47.4 voids per report. The average voided volume (VV) was lower in the EF patient population, 164.3 vs 204.3. Qmax and Qmean between EF vs In‐Office were almost identical, 23.3 vs 20.7 and 12.0 vs 11.0 respectively. Excluding flows < 125ml, EF VV increased to 215.1, Qmax 24.4, and Qmean 13.1. Similarly, the > 125ml office patients had an average VV 362, Qmax 28.1, and Qmean 16.3. For the 4 patients who had > 125ml voided with both modalities, the average VV EF vs office was 261.1 vs 351, Qmax 25.1 vs 26.9, Qmean 14.4 vs 15.4. One more patient achieved a VV of 125 using the app vs in office.IPSS scores were similar between EF and office, 7.6 total/QOL 0.9, vs 7.9 total/QOL 1.6 and consistent regardless of VV.Conclusions: Using a smartphone based app to perform at home uroflowmetry has many potential applications. In our post‐HOLEP patients, we found the EF results were similar to in office‐based uroflowmetry. Further study is necessary to determine if smartphone based uroflowmetry can supplant in‐ office studies. This has potential impact in reducing patient visits to the office which can help improve access and reduce healthcare costs.Funding: noneBS01‐08 How Mirabegron Affects the Human Ureter: An in Vitro StudyAhmet Gudeloglu1, Meylis Artykov1, Esin Ozcelebi2, Mehmet Yildirim Sara2, Alper Bektas Iskit2, Fazil Tuncay Aki11Department of Urology, Hacettepe University, 2Department of Pharmacology, Hacettepe UniversityPresented By: Ahmet GudelogluIntroduction: In this study, we aimed to investigate the effects of Mirabegron (MRB), a β3‐ adrenergic receptor agonist with current widespread clinical use in the treatment of overactive bladder disease, on isolated healthy human ureter.Methods: The approval of review board of the ethical committee was obtained prior to the study. This prospective study was designed as series of in vitro tissue experiments. Graft kidney's ureteral tissues of living donors who underwent surgery at our center between December 2020 and June 2021 were preferred. Informed consent was obtained from all patients. Ureters were transected harvested at the level of just above iliac crossing. Tissue transfer took place in the sealed flask containing pre‐gassed Krebs solution. Ureters were eventually detubularized and stripes were suspended in organ baths. The tissue activity was recorded after stripes were left to rest until spontaneous contractions were observed. Consequently, tissue responses were recorded by adding increasing concentrations of Mirabegron. The myogenic activity was recorded via electro‐mechanical transducer set‐up and AcqKnowledge® 4.2 (BIOPAC Systems, Inc.) software. Data analysis was performed with software SPSS 24.0 (IBM Corp., Chicago, USA) and GraphPad Prism 6 (GraphPad, La Jolla, CA, USA).Results: The total of 24 tissue strips from 16 ureters were prepared and studied. Of these, only 15 strips exhibited spontaneous or inducible activity. The effect of Mirabegron was examined in tissues with spontaneous activity. The data of strips without detectable activity was excluded from the study. It was determined that MRB lowered the frequency of spontaneous ureteric contraction in the concentration‐ dependent manner (Figure 1; A sample trace visualizing the effect of MRB in cumulative concentration on isolated ureteral strips. Molar concentrations are depicted in means of logarithmic value). The decrease in frequency was statistically significant in presence of MRB at 10‐6.5 ‐ 10‐4.5 M (Figure 2; Response values were proportioned with baseline contraction. All data in graphs is presented as arithmetic mean ± standard error of the mean. a p < 0.05, b p < 0.005). Also, the decrease in spontaneous contraction frequency in terms of percentage change was statistically significant at 10‐8 ‐ 10‐4.5 M. The MRB lowered the spontaneous ureteric contractile force in a dose‐dependent manner compared to the baseline contractile force. The decrease in amplitudes was statistically significant at 10‐7 ‐ 10‐4.5 M concentrations.Conclusions: The Mirabegron shows suppressive properties on the human ureter activity in vitro. This effect could be achieved in the dose‐dependent fashion in isolated tissue strips showing spontaneous activity.Funding: This study was financially supported by the Scientific Research Unit of Hacettepe University, Turkey.BS01‐09 Randall's Plaque‐Associated Macrophages Receive Chemokine Signaling from the Loop of HenleHeiko Yang1, Hanbing Song1, Thomas Chi1, Marshall Stoller1, Franklin Huang1, Sunita Ho11UCSFPresented By: Heiko Yang, MD, PhDIntroduction: We recently identified an embryonically derived tissue resident subpopulation of macrophages associated with Randall's plaques. These macrophages typically reside in the renal cortex in normal kidneys, so how they arrive at the papillary tip in stone formers is unclear. The objective of this study was to use our single nuclear RNA sequencing dataset to identify which cells at the papillary tip may be responsible for chemokine signaling to these macrophages.Methods: Randall's plaque and renal papillary tissues were collected from adult patients undergoing stone surgery. Randall's plaque tissue was obtained from endoscopic biopsies while whole renal papilla tissue were obtained from fresh nephrectomy specimens. Single nuclear RNA sequencing was performed using the 10X Genomics platform and Illumina NovaSeq S4. Additional tissue was saved for immunohistologic staining. Analysis was conducted using R Studio and Seurat. Intercellular molecular interactions were predicted using CellphoneDB.Results: CXCR4‐mediated chemokine signaling was found originating from epithelial cells in the loop of Henle. This interaction was highly specific to RP‐associated macrophages and was not predicted to originate from other epithelial or stromal cell types. Adhesion interactions via P‐selectin and E‐selectin were notably absent between vascular endothelial cells and RP‐associated macrophages, reinforcing a non‐hematologic origin.Conclusions: Epithelial cells at the loop of Henle may be responsible for attracting RP‐associated macrophages to the papillary tip. While the role of these macrophages in biomineralization is still being investigated, these results support the hypothesis that the loop of Henle is the functional location of Randall's plaque pathology.Funding: California Urology Foundation (HY), Program in Biomineralization Studies (SH)BS01‐10 Development of a Realistic Mouse Model of UrosepsisDirk Lange1, Roman Herout1, Sreeparna Vappala2, Sarah Hanstock1, Igor Moskalev3, Ben Chew1, Jayachandran Kizhakkedathu2, Dirk Lange11The Stone Centra at Vancouver General Hospital, Department of Urologic Sciences, University of British Columbia, 2Department of Pathology and Laboratory Medicine and Centre for Blood Research, The University of British Columbia, 3Vancouver Prostate Centre, Department of Urologic Sciences, University of British ColumbiaPresented By: Dirk Lange, PhDIntroduction: Murine models of sepsis, such as the cecal ligation and puncture (CLP) model, are typically polymicrobial and associated with a high mortality within hours after the specific intervention. To date, nomodels exist that follow the natural course of development from initial infection to sepsis, meaning that current models are not suitable to test the effiacy of interventions to prevent development to sepsis. To address this shortcoming, we developed a high‐throughput, murine model that mimics a slow‐paced, monomicrobial sepsis originating from the urinary tract.Methods: Twelve (12)‐week‐old male C57Bl/6 mice (n = 23) underwent percutaneous insertion of a 4mm catheter piece into the urinary bladder. The following day mice were divided into three groups differing in the number of bacteria introduced into the bladder of animals:group 1 ‐ 50 μl of a 1x10^8 CFU/ml solution (n = 10), group 2 ‐ 50 μl of a 1x10^7 CFU/ml solution (n = 10), and group 3 (sham mice) ‐ 50 μl of sterile saline (n = 3). On day 4 mice were sacrificed. The number of bacteria in urine, colonizing bladder catheters, adherent to/invaded into the bladder tissue as well as a set of (32) sepsis‐associated pro‐/anti‐inflammatory cytokines and chemokines were analyzed.Results: All 23 mice survived the postinterventional period. Mean weight loss was 11% in group 1, 9% in group 2 and 2% in the control group. Mean urine CFU counts were highest in group 1 and all sham mice had negative urine cultures. All infected mice had high catheter‐adhered bacterial counts. 18/20 infected mice had CFU counts in homogenized splenic tissue indicating septicemia. Cell‐free DNA and D‐Dimer was highest in group 1 and lowest in the control group. Serum levels of G‐CSF were significantly increased in group 1 when compared to controls. Serum levels of IL‐6, TNF‐a, IFN‐? and IL‐1ß were all elevated (1.5 to 30‐fold) compared to control mice.Conclusions: We present a monomicrobial murine model of urosepsis that follows the natural progression to sepsis from an initial urinary tract infection originating from an indwelling catheter. This model does not lead to rapid deterioration and death and can therefore be used as a model to test the efficacy of novel interventional strategies to prevent sepsis development.Funding: Roman Herout was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 447437311.BS01‐11 Composition and Structure of a Cystine Bladder StoneAmy Gosling1, Roanne Causey1, Chandra Shekhar Biyani2, Robert Simpson3, Ben Holley3, Antonia Borissova3, Andrew Scott31School of Medicine, Worsley Building, University of Leeds, 2Urology Department, St James's University Hospital, 3School of Chemical and Process Engineering, University of LeedsPresented By: Amy GoslingIntroduction: Cystinuria is an autosomal recessive condition resulting in the supersaturation of cystine in the urine and subsequent crystallisation. Despite only accounting for 2% of all urolithiasis, the 5‐year recurrence rate for cystine stones is high at approximately 83%. The current understanding of the growth mechanisms of urinary stones is limited. Characterisation of urinary stones is essential to improve understanding of the formation of urolithiasis, allowing for the identification of major and trace components and morphological features and structure. The existing standard analysis technique is Fourier‐transform infrared spectroscopy (FT‐IR), however, a wider range of characterisation techniques is advisable for a thorough understanding of stone composition and growth. These results will be used to suggest a protocol for stone analysis.Methods: Three intact stones were removed from an 80‐year‐old male, undergoing treatment for prostate cancer. The stones were removed by an open cystolithotomy because of the size. There was no positive family history of cystinuria. The three ovoid stones (two ∼6 cm, one ∼3 cm in length) were superficially similar. One stone was cut in half to reveal the internal structure. The surface of the stone was imaged using stereo and reflected light microscopy. Higher‐resolution imaging and elemental information were performed using scanning electron microscopy (SEM). Crystalline phases were identified by X‐ray diffraction (XRD). Results were compared with FT‐IR spectra. A 30‐micrometre thin section of the smaller stone was produced to enable polarised transmitted light microscopy.Results: Light microscopy visualised a central core of large crystals surrounded by concentric growth rings emanating from the centre of the stone (Fig.). XRD revealed a single, crystalline phase, cystine. SEM imaging and elemental analysis (EDX) showed hexagonal crystals (cystine) together with amorphous, spherical calcium phosphate particles (∼5 μm) clustered near the core and in concentric rings within the stone. FT‐IR spectra were consistent with cystine and calcium phosphate.Conclusions: We have demonstrated that a wide range of characterisation techniques is necessary to clearly understand the structure and composition of cystine stones. Protocols for the analysis of urinary tract stones should combine multiple methods of characterisation to aid in the understanding of stone formation.Funding: NilBS01‐12 When Does Pyelovenous Backflow Occur? the Effect of Raised Intrarenal Pressures on an Ex Vivo Animal ModelAnne Hong1, Justin Du Plessis1, Greg Jack1, Cliodhna Browne1, Damien Bolton11Austin HealthPresented By: Anne Hong, MDIntroduction: Elevated intrarenal pressures (IRPs) are common during ureteroscopies and may have implications for post operative complications. However, little is known about the microscopic processes that transpire during pathogenesis complications. We aimed to document the histological changes observed in renal units subjected to elevated IRPs and postulate the possible mechanisms of infectious complications.Methods: 21 ex vivo porcine kidney models were used. Each ureter was cannulated with a 10Fr dual lumen ureteric catheter (Boston Scientific, Massachusetts, United States) with the proximal end at the pelviureteric junction. The distal end of the ureter was secured to form a leak‐proof seal around the ureteric catheter. A 0.014” pressure sensing wire (Comet II Pressure Guidewire®, Boston Scientific, Massachusetts, United States) was inserted through one lumen and with the sensor positioned in the renal pelvis for IRP measurement. Undiluted India ink stain (Royal Talens, Apeldoorn, Netherlands) was irrigated through the second lumen. Each renal unit was subjected to India ink Irrigation at target IRPs of 5mmHg (control), 30mmHg, 60mmHg, 90mmHg, 120mmHg 150mmHg and 200mmHg. 3 renal units subjected to each target IRP. After irrigation, each renal unit was processed by a uropathologist with haematoxylin and eosin, and examined under low and high power magnification.Results: India ink stain was observed in the collecting ducts at 5mmHg. Signs of pressure as represented by collecting duct dilatation was first observed at 60mmHg (Figure A). Stain was consistently observed in the distal convoluted tubules at ≥60mmHg, all renal units showed renal cortex involvement. At ≥90mmHg, stain was observed in venous structures (Figure B). At 200mmHg, stain was observed in supportive tissue, peritubular capillaries and glomerular capillaries.Conclusions: Demonstration of vascular involvement is required to account for septic complications. This occurred at IRP of ≥90mmHg in ex vivo porcine models.Funding: The authors did not receive any funding for this researchBS01‐13 Transcriptomic Workflow for Microbiome Profiling of the Genitourinary TractJose Agudelo1, Sromona Mukherjee1, Mangesh Suryavanshi1, Ava Adler1, Thien