Abstracts from the New England Section of the AUA 2021

NE-AUA 2021 Abstracts Scientific Session III: BPH/RECON 24 Describing the Urinary Microbiome in Pre-operative Urine Specimens of Lichen Sclerosus Induced and Non-Lichen Sclerosus Induced Urethral Stricture Disease Amanda Sherman,MD 1 , Travis Sullivan,MS 1 , HarjivanKohli,MD 1 , Eric Burks, MD 2 , Kimberly Rieger-Christ, PhD 1 , Alex Vanni, MD 1 1 Lahey Hospital and Medical Center, Burlington, MA, USA; 2 Boston Medical Center, Boston, MA, USA. Introduction: Lichen sclerosus (LS) is a chronic inflammatory condition that can affect both the penile skin and urethral epithelium in men. Over time, severe impairment of sexual and urinary function can result, from preputial adhesions and phimosis, skin tearing with erections, acquired buried penis, and urethral stricture disease (USD). The pathophysiology of LS USD is poorly understood, with a heterogeneous presentation and disease severity. This study seeks to describe differences in the urinary microbiome of patients with pathologically confirmed LS USD vs. non-LS USD. Materials & Methods: An IRB-approved protocol of men with USD was performed. Pre-operative clean-catch voided urine was collected in 34 men with pathologically confirmed LS USD and non-LS USD. Bacterial genomic DNAwas extracted using the PowerMag Soil DNA Isolation Kit. 16S rRNA gene sequencing was performed using the MiSeq platform for paired-end sequencing. Amplicon sequence variants (ASVs) were generated via dada2 v1.16.0. ASV taxonomy was assigned up to genus level using the SILVAv.138 database. The pathologic evaluation of strictures was based on 5 typical histologic features of LS (Prabhu et al 2013). For the purpose of this study, two groups were formed based on the following LS score: non-LS strictures (LS score 0-1) and LS strictures (LS score 3-5). Results: Sufficient bacterial DNAfor analysis was obtained from 19 patients (10 non-LS USD and 9 LS USD). Significant differences in alpha diversity (within sample variance) and beta diversity (between sample variance) were observed (p<0.05) between the two cohorts. β diversity, as described by observed ASV, showed median ASVs for NLS samples were 25, whereas LS were 57 (p=0.016). β diversity is significantly different between scores 0 and 5 (p<0.05) by PERMANOVAanalysis including Bray-Curtis, andweighted and unweighted UniFrac scores. 2 phyla were noted to be significantly different between status groups, bacteroidota more common in LS (p=0.012) and firmicutes more present in NLS (p=0.037). Overall, alpha and beta diversity of samples is statistically significant between disease status groups, with a trend towards increasing diversity with higher pathologic scores. Conclusions: LS USD exhibits significant alterations in diversity and differential abundance of urine microbiota compared to non-LS USD controls, with a trend of diversity increasing along with pathologic LS score. While further validation in a larger sample is necessary, this finding could be used to guide further investigation into the role of bacteria and the urinary microbiome in LS USD pathogenesis, the severity of presentation, and stricture recurrence. Variable Growth Patterns of Transition vs. Peripheral Zones of Prostate - Implications for BPH Therapy Christina Sharkey, MLA , Xingbo Long, MD, Zongwei Wang, PhD, Ra’adAl- Faouri, MD, Boris Gershman, MD, Leo L. Tsai, MD, PhD, Aria F. Olumi, MD Beth Israel Deaconess Medical Center, Boston, MA, USA Introduction: As men age, the prostate gland continues to grow at around 2.9%per year depending on the initial prostate size. While the variable growth rate of the total prostate gland is recognized, the growth rate patterns of the different prostate zones among adult males remain largely unclear. The continuous prostate growth leads to the development of Benign Prostatic Hyperplasia (BPH) in elderly men. 5-alpha reductase inhibitors (5ARIs) are one of the main medical therapies for BPH and are known to reduce the total prostate size. Here, we evaluated the growth rate patterns of different prostate zones and measured the effect of 5ARI treatment on zonal growth rates. Materials & Methods: Prostate MRI data and clinical information were obtained retrospectively on 160 patients who had a history of BPH or low- grade prostate cancer and underwent at least three prostate MRIs between 2003 and 2018. Prostate volume was measured and calculated for the central gland, peripheral gland, and total prostate. The outcome was analyzed using linear regression. Results: We observed that prostate growth rates vary depending on age, the prostate zone, and 5ARI use. Body mass index (BMI) and Transition zone index (TZI) are associated with the growth rate of the peripheral zone (p=0.027, p<0.001 respectively), but not the central zone growth rate. 5ARI use is significantly associated with the reduction in the central zone growth rate (Regression coefficient [RO]: -0.123 to -0.005; p=0.035), not the peripheral zone. In addition, patients with TZI greater than 60% had the most significant reduction in the central zone growth rate while taking 5ARI (RO: -0.151 to -0.063; p<0.001). Conclusions: The growth pattern of the prostate varies between the central and peripheral zones and is dependent on age and BMI. In addition, reduction of the prostate size as a result of the 5ARI treatment occurs mainly in the central zone. Patients with TZI greater than 60% had the greatest reduction of the central zone growth rate with 5ARI treatment. 23 13