Robert H. Blackwell

Urothelial cells undergo epithelial-to-mesenchymal transition after exposure to muscle invasive bladder cancer exosomes

Bladder cancer, the fourth most common noncutaneous malignancy in the United States, is characterized by high recurrence rate, with a subset of these cancers progressing to a deadly muscle invasive form of disease. Exosomes are small secreted vesicles that contain proteins, mRNA and miRNA, thus potentially modulating signaling pathways in recipient cells. Epithelial-to-mesenchymal transition (EMT) is a process by which epithelial cells lose their cell polarity and cell–cell adhesion and gain migratory and invasive properties to become mesenchymal stem cells. EMT has been implicated in the initiation of metastasis for cancer progression. We investigated the ability of bladder cancer-shed exosomes to induce EMT in urothelial cells. Exosomes were isolated by ultracentrifugation from T24 or UMUC3 invasive bladder cancer cell conditioned media or from patient urine or bladder barbotage samples. Exosomes were then added to the urothelial cells and EMT was assessed. Urothelial cells treated with bladder cancer exosomes showed an increased expression in several mesenchymal markers, including α-smooth muscle actin, S100A4 and snail, as compared with phosphate-buffered saline (PBS)-treated cells. Moreover, treatment of urothelial cells with bladder cancer exosomes resulted in decreased expression of epithelial markers E-cadherin and β-catenin, as compared with the control, PBS-treated cells. Bladder cancer exosomes also increased the migration and invasion of urothelial cells, and this was blocked by heparin pretreatment. We further showed that exosomes isolated from patient urine and bladder barbotage samples were able to induce the expression of several mesenchymal markers in recipient urothelial cells. In conclusion, the research presented here represents both a new insight into the role of exosomes in transition of bladder cancer into invasive disease, as well as an introduction to a new platform for exosome research in urothelial cells.

Osteopontin—A Master Regulator of Epithelial-Mesenchymal Transition

Osteopontin (OPN) plays an important functional role in both physiologic and pathologic states. OPN is implicated in the progression of fibrosis, cancer, and metastatic disease in several organ systems. The epithelial-mesenchymal transition (EMT), first described in embryology, is increasingly being recognized as a significant contributor to fibrotic phenotypes and tumor progression. Several well-established transcription factors regulate EMT and are conserved across tissue types and organ systems, including TWIST, zinc finger E-box-binding homeobox (ZEB), and SNAIL-family members. Recent literature points to an important relationship between OPN and EMT, implicating OPN as a key regulatory component of EMT programs. In this review, OPN’s interplay with traditional EMT activators, both directly and indirectly, will be discussed. Also, OPN’s ability to restructure the tissue and tumor microenvironment to indirectly modify EMT will be reviewed. Together, these diverse pathways demonstrate that OPN is able to modulate EMT and provide new targets for directing therapeutics.

The Role of Cancer-Derived Exosomes in Tumorigenicity & Epithelial-to-Mesenchymal Transition

Epithelial-to-mesenchymal transition (EMT) is a process by which epithelial cells lose their basement membrane interaction and acquire a more migratory, mesenchymal phenotype. EMT has been implicated in cancer cell progression, as cells transform and increase motility and invasiveness, induce angiogenesis, and metastasize. Exosomes are 30–100 nm membrane-bound vesicles that are formed and excreted by all cell types and released into the extracellular environment. Exosomal contents include DNA, mRNA, miRNA, as well as transmembrane- and membrane-bound proteins derived from their host cell contents. Exosomes are involved in intercellular signaling, both by membrane fusion to recipient cells with deposition of exosomal contents into the cytoplasm and by the binding of recipient cell membrane receptors. Recent work has implicated cancer-derived exosomes as an important mediator of intercellular signaling and EMT, with resultant transformation of cancer cells to a more aggressive phenotype, as well as the tropism of metastatic disease in specific cancer types with the establishment of the pre-metastatic niche.

Functional Implications of Renal Tumor Enucleation Relative to Standard Partial Nephrectomy

OBJECTIVE To compare the surgical precision for optimizing nephron-mass preservation of tumor enucleation (TE) vs standard partial nephrectomy (SPN), with primary focus on functional outcomes. TE is presumed to optimize preservation of parenchymal mass and function but this has not yet been rigorously studied and quantified. MATERIALS AND METHODS Robotic partial nephrectomy patients who had appropriate pre- and postoperative studies for analysis of parenchymal mass preservation specific to the operated kidney were included. Computed tomography or magnetic resonance imaging and estimated glomerular filtration rate were required to be <2 months prior and 4-12 months after surgery. Parenchymal mass preservation and surgical precision were estimated for each technique, with precision defined as actual postoperative parenchymal volume or predicted postoperative parenchymal volume, presuming loss of a 5 mm rim of parenchyma associated with tumor excision and reconstruction. RESULTS Analysis included 57 TE and 53 SPN. Median age, body mass index, and tumor size were comparable. Percent parenchymal mass preserved in the operated kidney with TE was 96% (interquartile range [IQR] = 90-100) vs 89% (IQR = 83-96) for SPN (P = .003). Precision of excision or reconstruction was 101% (IQR = 96-105) for TE vs 94% (IQR = 88-100) for SPN (P < .001). On multivariable analysis, only TE correlated with improved surgical precision (coefficient = 6.7, 95% confidence interval = 1.6-11.8, P = .01). Although preservation of global renal function also favored TE, the differences were marginal (96% vs 93%), and statistical significance was not observed (P = .2). CONCLUSION Our analysis, which specifically focuses on the functional implications of TE, demonstrates that TE maximally spares normal parenchyma compared to SPN. Thus far, functional differences remain marginal and not statistically significant. Clinical significance of these findings in various clinical settings will require further investigation.

Postoperative Atrial Fibrillation Predicts Long-Term Cardiovascular Events after Radical Cystectomy

PURPOSE Postoperative atrial fibrillation after radical cystectomy occurs in 2% to 8% of cases. Recent evidence suggests that transient postoperative atrial fibrillation leads to future cardiovascular events. The long-term cardiovascular implications of postoperative atrial fibrillation in patients undergoing radical cystectomy are largely unknown. MATERIALS AND METHODS The Healthcare Cost and Utilization Project State Inpatient Databases for California and Florida were used to identify patients who underwent radical cystectomy between 2007 and 2010. After excluding patients with a history of atrial fibrillation, coronary artery disease and/or stroke, patients were matched using propensity scoring on age, race, insurance status and preexisting comorbidities. Adjusted Kaplan-Meier time-to-event analysis and Cox proportional hazards models were used to assess the effect of postoperative atrial fibrillation on cardiovascular events (acute myocardial infarction and stroke) during postoperative year 1. RESULTS Radical cystectomy was performed in 4,345 patients who met the study inclusion criteria, of whom 210 (4.8%) had postoperative atrial fibrillation. There was a significantly higher cumulative incidence of cardiovascular events during the first postoperative year in patients in whom postoperative atrial fibrillation developed (24.8% vs 10.9%, adjusted log rank p=0.007). Cox proportional hazards regression demonstrated an increased risk of cardiovascular events in patients with postoperative atrial fibrillation (HR 10, p=0.02). CONCLUSIONS Our results demonstrate that patients undergoing radical cystectomy in whom transient postoperative atrial fibrillation develops are at significantly increased risk for cardiovascular events in the first postoperative year. Physicians should be vigilant in assessing postoperative atrial fibrillation, even when transient, and establish appropriate followup given the increased risk of cardiovascular morbidity.

Open Versus Robotic Radical Prostatectomy in Obese Men

Objectives: Robotic-assisted radical prostatectomy (RARP) has been shown to reduce blood loss, peri-operative complications and length of stay when compared to open radical prostatectomy (ORP). We sought to determine whether the reported benefits of RARP over ORP translate to obese patients. Patients and Methods: We utilized the 2009-2010 Nationwide Inpatient Sample to identify all obese men with prostate cancer who underwent ORP and RARP. Our primary outcome was the presence of a peri-operative adverse event (i.e. blood transfusion, complication, prolonged length of stay). We fit multivariable logistic regression models to examine whether RARP in obese patients was independently associated with decreased odds of all three outcomes. Results: We identified 9,108 obese patients who underwent radical prostatectomy. On multivariable analysis, the use of RARP in the obese population was not independently associated with decreased odds of developing a peri-operative complication (OR = 0.81, CI: 0.58-1.13, p = 0.209). RARP was, however, associated with decreased odds of blood transfusion (OR = 0.17, CI: 0.10-0.30, p < 0.001) and prolonged length of stay (OR = 0.28, CI: 0.20-0.40, p < 0.001). Conclusion: Our findings suggest that in obese patients, the use of RARP may reduce length of stay and blood transfusions compared to ORP. Both approaches, however, are associated with similar odds of developing a complication.

Rates and Risk Factors for Opioid Dependence and Overdose after Urological Surgery

Purpose: Effective pain management is a critical component of the perioperative process with opioids representing a mainstay of therapy. The opioid epidemic is a growing concern in the United States. The goal of this study was to quantify the risk of opioid dependence or overdose among patients undergoing urological surgery and to identify risk factors of opioid dependence or overdose. Materials and Methods: We retrospectively reviewed data on urological surgery from 2007 to 2011. Data sources included the HCUP (Healthcare Cost and Utilization Project) inpatient, ambulatory surgery and emergency department data sets. Outcomes of postoperative opioid dependence and overdose were identified by previously validated ICD‐9 codes. Multivariable logistic regression adjusted for surgical procedure was performed to identify predictors of opioid dependence or overdose following urological surgery. Results: Overall 675,527 patients underwent urological surgery, of whom 0.09% were diagnosed with opioid dependence or overdose. Patients in whom opioid dependence or overdose developed were younger (median age 51 vs 62 years), carried nonprivate insurance (69.6% vs 66%), underwent an inpatient procedure (81.0% vs 42.4%) and had a longer length of stay (median 3 vs 0 days) and a history of depression (14.4% vs 3.4%) or chronic obstructive pulmonary disease (20.3% vs 8.9%, all p <0.001). On adjusted multivariable analysis these factors remained independent risk factors for opioid dependence or overdose. Conclusions: Postoperative opioid dependence or overdose affects 1 of 1,111 urological surgery patients. Risk factors for opioid dependence or overdose included younger age, inpatient surgery and increasing hospitalization duration, baseline depression, tobacco use and chronic obstructive pulmonary disease as well as insurance provider, including Medicaid, Medicare (age less than 65 years) and noninsured status.

Take the Volume Pledge may result in disparity in access to care.

Background. “Take the Volume Pledge” proposes restricting pancreatectomies to hospitals that perform ≥20 per year. Our purpose was to identify those factors that characterize patients at risk for loss of access to pancreatic cancer care with enforcement of volume standards. Methods. Using the Healthcare Cost and Utilization Project State Inpatient Database from Florida, we identified patients who underwent pancreatectomy for pancreatic malignancy from 2007–2011. American Hospital Association and United States Census Bureau data were linked to patient‐level data. High‐volume hospitals were defined as performing ≥20 pancreatic resections per year. Univariable and multivariable statistics compared patient characteristics and utilization of high‐volume hospitals. Classification and Regression Tree modeling was used to predict patients at risk for losing access to care. Results. Our study included 1,663 patients. Five high‐volume hospitals were identified, and they treated 1,056 (63.5%) patients. Patients residing far from high‐volume hospitals, in areas with the highest population density, non‐Caucasian ethnicity, and greater income had decreased odds of obtaining care at high‐volume hospitals. Using these factors, we developed a Classification and Regression Tree–based predictive tool to identify these patients. Conclusion. Implementation of “Take the Volume Pledge” is an important step toward improving pancreatectomy outcomes; however, policymakers must consider the potential impact on limiting access and possible health disparities that may arise.

Functional Comparison of Renal Tumor Enucleation Versus Standard Partial Nephrectomy

BACKGROUND Tumor enucleation (TE) optimizes parenchymal preservation and could yield better function than standard partial nephrectomy (SPN), although data on this are conflicting. OBJECTIVE To compare functional outcomes for TE and SPN strategies. DESIGN, SETTING, AND PARTICIPANTS Patients managed with partial nephrectomy (PN) with necessary data for analysis of preservation of ipsilateral parenchymal mass (IPM) and global glomerular filtration rate (GFR) from two centers were included. All studies were required <2 mo before and 3-12 mo after surgery. Patients with a solitary kidney or multifocal tumors were excluded. INTERVENTION Partial nephrectomy. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Vascularized IPM was estimated from contrast-enhanced CT scans preoperatively and postoperatively. Serum creatinine-based estimates of global GFR were also obtained in the same timeframes. Univariable and multivariable linear regression evaluated factors associated with new-baseline global GFR. RESULTS/LIMITATIONS Analysis included 71 TE and 373 SPN cases. The median preoperative global GFR was comparable for TE and SPN (75 vs 78ml/min/1.73m2; p=0.6). The median tumor size was 3.0cm for TE and 3.3cm for SPN (p=0.03). The median RENAL score was 7 in both cohorts. For TE, warm ischemia and zero ischemia were used in 51% and 49% of cases, respectively. For SPN, warm ischemia and cold ischemia were used in 72% and 28% of patients, respectively. Capsular closure was performed in 46% of TE and 100% of SPN cases (p<0.001). Positive margins were found in 8.5% of TE and 4.8% of SPN patients (p=0.2). The median vascularized IPM preserved was 95% (interquartile range [IQR] 91-100%) for TE and 84% (IQR 76-92%) for SPN (p<0.001). The median global GFR preserved was 101%(IQR 93-111%) and 89% (IQR 81-96%) for TE and SPN, respectively (p<0.001). On multivariable analysis, resection strategy, preoperative GFR, and vascularized IPM preserved were all significantly associated (p<0.001) with new-baseline global GFR. Limitations include the retrospective design and the lack of resection outcome data. CONCLUSIONS Our analysis suggests that TE has potential for maximum IPM preservation compared to SPN and may provide optimized functional recovery. Further investigation will be required to evaluate the clinical significance of these findings. PATIENT SUMMARY Tumor enucleation for kidney cancer involves dissection along the tumor capsule and optimally preserves normal kidney tissue, which may lead to better functional recovery. The importance of this approach in various clinical settings will require further investigation.

Incidence of Adverse Contrast Reaction Following Nonintravenous Urinary Tract Imaging

Adverse reactions (ARs) to intravenous (IV) radiographic contrast range from mild urticaria to life-threatening anaphylaxis. Intraluminal contrast dye is routinely used in the urinary tract with a minimal perceived risk of AR. We used the Healthcare Cost and Utilization Project State Inpatient Databases for California and Florida from 2007 to 2011 to identify patients who received urinary tract contrast dye for retrograde pyelography, percutaneous pyelography, retrograde/other cystogram, and ileal conduitogram. After excluding patients who had received IV contrast for other radiologic studies, ARs to contrast were identified by a composite end point of diagnoses not present on admission including shock, anaphylaxis, iatrogenic hypotension, urticaria, angioedema, laryngospasm, laryngeal edema, and/or a new diagnosis of contrast reaction. Overall, 76 174 patients were included who had undergone non-IV urinary tract imaging, 367 (0.48%) of whom developed an AR. On multivariate analysis, receipt of contrast in the lower urinary tract (odds ratio [OR]: 1.8; p=0.04) or upper urinary tract by retrograde pyelography (OR: 1.6; p=0.04) or antegrade pyelography (OR: 2.0; p=0.007) increased the risk of AR compared with control patients. The use of contrast dye in the urinary tract is associated with a low, but present risk of AR. PATIENT SUMMARY We looked at patients who underwent a urologic procedure using radiographic contrast media in the urinary tract. Although adverse reactions (ARs) may occur with the use of contrast media in the urinary tract, these reactions are experienced by a minority of patients (approximately 1 in 200). In addition, we found that an allergy to intravenous contrast does not increase a patients risk of an AR to contrast within the urinary tract.