Urine Biopsy as Dynamic Biomarker to Enhance Clinical Staging of Bladder Cancer in Radical Cystectomy Candidates.

PURPOSE: There is significant interest in identifying complete responders to neoadjuvant chemotherapy (NAC) before radical cystectomy (RC) to potentially avoid removal of a pathologically benign bladder. However, clinical restaging after NAC is highly inaccurate. The objective of this study was to develop a next-generation sequencing-based molecular assay using urine to enhance clinical staging of patients with bladder cancer. METHODS: Urine samples from 20 and 44 patients with bladder cancer undergoing RC were prospectively collected for retrospective analysis for molecular correlate analysis from two clinical trials, respectively. The first cohort was used to benchmark the assay, and the second was used to determine the performance characteristics of the test as it correlates to responder status as measured by pathologic examination. RESULTS: First, to benchmark the assay, known mutations identified in the tissue (MT) of patients from the Accelerated Methotrexate, Vinblastine, Doxorubicin, Cisplatin trial (ClinicalTrials.gov identifier: NCT01611662, n = 16) and a cohort from University of California-San Francisco (n = 4) were cross referenced against mutation profiles from urine (MU). We then determined the correlation between MU persistence and residual disease in pre-RC urine samples from a second prospective clinical trial (The pT0 trial; ClinicalTrials.gov identifier: NCT02968732). Residual MU status correlated strongly with residual disease status (pT0 trial; n = 44; P = .0092) when MU from urine supernatant and urine pellet were assessed separately and analyzed in tandem. The sensitivity, specificity, PPV, and NPV were 91%, 50%, 86%, and 63% respectively, with an overall accuracy of 82% for this second cohort. CONCLUSION: MU are representative of MT and thus can be used to enhance clinical staging of urothelial carcinoma. Urine biopsy may be used as a reliable tool that can be further developed to identify complete response to NAC in anticipation of safe RC avoidance.

Atypical Causes of Gastroparesis: Prevalence, Gastric Emptying, and Clinical Features.

BACKGROUND: Gastroparesis is commonly attributed to idiopathic or diabetic causes. GOALS: We aimed to describe atypical causes of gastroparesis and examine the clinical features and severity of delayed gastric emptying compared with idiopathic and diabetic causes. STUDY: Between 2018 and 2021, gastroparesis patients being evaluated at our tertiary care center completed a 4-hour gastric emptying scintigraphy and questionnaires assessing for gastrointestinal disorders, including patient assessment of upper gastrointestinal symptoms. Patients were divided into groups relating to gastroparesis cause: diabetic, postsurgical (PSGp), connective tissue (CTGp), neurological and idiopathic. RESULTS: Two hundred fifty-six patients with delayed emptying on gastric emptying scintigraphy completed the questionnaires. Gastroparesis causes included 149 (58.2%) idiopathic, 60 (23.4%) diabetic, 29 (11.3%) postsurgical, 13 (5.1%) connective tissue, and 5 (2.0%) neurological. In each group, most patients were female and White. Gastric retention at 4 hours was significantly greater in patients with diabetic (39.3±25.7% P <0.001), postsurgical (41.3±24.0% P =0.002), and connective tissue gastroparesis (37.8±20.0% P =0.049) compared with patients with idiopathic gastroparesis (25.5±17.6%). In PSGp, diabetic and idiopathic causes, the main symptoms were early satiety and postprandial fullness, whereas in CTGp, bloating and abdominal distension were the predominant symptoms. Vomiting severity was significantly greater in patients with diabetes compared with idiopathic gastroparesis (2.9±1.9 vs. 2.1±1.8 P =0.006). CONCLUSIONS: Atypical causes contributed to gastroparesis in 47 of 256 (18.4%) patients with delayed gastric emptying. Gastric emptying was significantly more delayed in PSGp and CTGp patients. PSGp patients mainly experienced stomach fullness and early satiety, whereas CTGp patients had predominantly bloating and distension.

TonB-dependent heme iron acquisition in the tsetse fly symbiont Sodalis glossinidius.

Sodalis glossinidius is an intra- and extracellular symbiont of the tsetse fly (Glossina sp.), which feeds exclusively on vertebrate blood. S. glossinidius resides in a wide variety of tsetse tissues and may encounter environments that differ dramatically in iron content. The Sodalis chromosome encodes a putative TonB-dependent outer membrane heme transporter (HemR) and a putative periplasmic/inner membrane ABC heme permease system (HemTUV). Because these gene products mediate iron acquisition processes by other enteric bacteria, we characterized their regulation and physiological role in the Sodalis/tsetse system. Our results show that the hemR and tonB genes are expressed by S. glossinidius in the tsetse fly. Furthermore, transcription of hemR in Sodalis is repressed in a high-iron environment by the iron-responsive transcriptional regulator Fur. Expression of the S. glossinidius hemR and hemTUV genes in an Escherichia coli strain unable to use heme as an iron source stimulated growth in the presence of heme or hemoglobin as the sole iron source. This stimulation was dependent on the presence of either the E. coli or Sodalis tonB gene. Sodalis tonB and hemR mutant strains were defective in their ability to colonize the gut of tsetse flies that lacked endogenous symbionts, while wild-type S. glossinidius proliferated in this same environment. Finally, we show that the Sodalis HemR protein is localized to the bacterial membrane and appears to bind hemin. Collectively, this study provides strong evidence that TonB-dependent, HemR-mediated iron acquisition is important for the maintenance of symbiont homeostasis in the tsetse fly, and it provides evidence for the expression of bacterial high-affinity iron acquisition genes in insect symbionts.