Citations

It has been challenging to produce ex vivo models of the inclusion pathologies that are hallmark pathologies of many neurodegenerative diseases. Using three-dimensional mouse brain slice cultures (BSCs), we have developed a paradigm that rapidly and robustly recapitulates mature neurofibrillary inclusion and Lewy body formation found in Alzheimer’s and Parkinson’s disease, respectively. This was achieved by transducing the BSCs with recombinant adeno-associated viruses (rAAVs) that express α-synuclein or variants of tau. Notably, the tauopathy BSC model enables screening of small molecule therapeutics and tracking of neurodegeneration. More generally, the rAAV BSC “toolkit” enables efficient transduction and transgene expression from neurons, microglia, astrocytes, and oligodendrocytes, alone or in combination, with transgene expression lasting for many months. These rAAV-based BSC models provide a cost-effective and facile alternative to in vivo studies, and in the future can become a widely adopted methodology to explore physiological and pathological mechanisms related to brain function and dysfunction.

AbstractPrimary aneurysmal bone cyst (ABC) is a benign multiloculated cystic lesion of bone that is defined cytogenetically by USP6 gene rearrangements. Rearrangements involving USP6 are promoter swaps, usually generated by fusion of the noncoding upstream exons of different partner genes with exon 1 or 2 of USP6, thus leading to transcriptional upregulation of full‐length USP6 coding sequence. Testing for USP6 rearrangements is used diagnostically to distinguish it from secondary ABC and other giant cell‐rich primary bone tumors. In this report, we present a case of a 16‐year‐old male with a primary ABC of the left distal femur. USP6 break apart fluorescence in situ hybridization was positive for a rearrangement and conventional chromosome analysis identified a reciprocal X;17 translocation. In order to identify the putative USP6 fusion partner, we performed RNA sequencing and uncovered a novel USP9X‐USP6 promoter swap fusion. This result was confirmed by reverse transcription‐polymerase chain reaction (RT‐PCR) and by mate pair sequencing thus showing the utility of these alternative methodologies in identifying novel fusion candidates. Ubiquitin‐specific protease 9X (USP9X), like USP6, encodes a highly conserved substrate‐specific deubiquitylating enzyme. USP9X is highly expressed in a number of tissue types and acts as both an oncogene and tumor suppressor in several human cancers. We conclude that oncogenic activation of USP6 via USP9X promoter exchange represents a novel driver of primary ABC formation.

Tumor recurrence in glioblastoma multiforme (GBM) is often attributed to acquired resistance to the standard chemotherapeutic agent, temozolomide (TMZ). Promoter methylation of the DNA repair gene MGMT (O6-methylguanine–DNA methyltransferase) has been associated with sensitivity to TMZ, whereas increased expression of MGMT has been associated with TMZ resistance. Clinical studies have observed a downward shift in MGMT methylation percentage from primary to recurrent stage tumors; however, the evolutionary processes that drive this shift and more generally the emergence and growth of TMZ-resistant tumor subpopulations are still poorly understood. Here, we develop a mathematical model, parameterized using clinical and experimental data, to investigate the role of MGMT methylation in TMZ resistance during the standard treatment regimen for GBM—surgery, chemotherapy, and radiation. We first found that the observed downward shift in MGMT promoter methylation status between detection and recurrence cannot be explained solely by evolutionary selection. Next, our model suggests that TMZ has an inhibitory effect on maintenance methylation of MGMT after cell division. Finally, incorporating this inhibitory effect, we study the optimal number of TMZ doses per adjuvant cycle for patients with GBM with high and low levels of MGMT methylation at diagnosis.

Abstract Cancer transmission with organ donation has been previously reported with a variety of malignancies and organ transplants. The risk of transmission through organ transplantation from donors with a history of previously treated malignancies has been addressed by guidelines from transplant societies. Herein, we report a case of a patient who developed lung cancer confined to the liver after liver transplantation with no known history of malignancy in the donor. The suspicion of donor origin arose after positron emission tomography-computerized tomography scan showed metastatic lung cancer only involving the transplanted liver without a primary focus. Genetic analysis of the malignant cells confirmed donor origin of the cancer.

Objective To present 6‐month safety and effectiveness data from a multicentre prospective study of aquablation in men with lower urinary tract symptoms (LUTS) attributable to benign prostatic hyperplasia ( BPH ) with prostate volumes between 80 and 150 mL. Methods Between September and December 2017, 101 men with LUTS attributable to BPH were prospectively enrolled at 16 centres in Canada and the USA. Results The mean prostate volume was 107 mL. The mean length of hospital stay after the aquablation procedure was 1.6 days (range: same day to 6 days). The primary safety endpoint (Clavien–Dindo grade 2 or higher or any grade 1 event resulting in persistent disability) at 3 months occurred in 45.5% of men, which met the study design goal of < 65% ( P < 0.001). At 6 months, 22% of the patients had experienced a Clavien–Dindo grade 2, 14% a grade 3 and 5% a grade 4 adverse event. Bleeding complications requiring intervention and/or transfusion were recorded in eight patients prior to discharge and in six patients after discharge. The mean International Prostate Symptom Score improved from 23.2 ± 6.3 at baseline to 6.7 ± 5.1 at 3 months, meeting the study's primary efficacy endpoint goal ( P < 0.001). The maximum urinary flow rate increased from 8.7 to 18.8 mL/s ( P < 0.001) and post‐void residual urine volume decreased from 131 at baseline to 47 at 6 months ( P < 0.0001). At 6 months, prostate‐specific antigen concentration reduced from 7.1 ± 5.9 ng/mL at baseline to 4.0 ± 3.9 ng/mL, a 44% reduction. Conclusions Aquablation is safe and effective in treating men with larger prostates (80–150 mL), without significant increase in procedure or resection time.

Background: For patients undergoing 2-stage exchange for the treatment of periprosthetic joint infection (PJI) following total knee arthroplasty, the long-term risk of reinfection and mechanical failure and long-term clinical outcomes are not well known. The purpose of our study was to determine the long-term clinical results of 2-stage exchange for PJI following total knee arthroplasty. Methods: We identified 245 knees that had undergone total knee arthroplasty and were subsequently treated with 2-stage exchange due to infection during the period of 1991 to 2006; the cohort had no prior treatment for PJI. Major, or 4 of 6 minor, Musculoskeletal Infection Society (MSIS) diagnostic criteria were fulfilled by 179 (73%) of the knees. The cumulative incidence of reinfection and of aseptic revision, accounting for the competing risk of death, were calculated. Risk factors for reinfection were evaluated using Cox proportional hazards regression. Knee Society Score (KSS) values were calculated. The mean age at spacer insertion was 68 years; 50% of the patients were female. The mean follow-up was 14 years (range, 2 to 25 years) following reimplantation. Results: The cumulative incidence of reinfection was 4% at 1 year, 14% at 5 years, 16% at 10 years, and 17% at 15 years. Factors that were predictive of reinfection included a body mass index of ≥30 kg/m 2 (hazard ratio [HR], 3.1; p < 0.01), previous revision surgery (HR, 2.8; p < 0.01), and a McPherson host grade of C (HR, 2.5; p = 0.04). The cumulative incidence of aseptic revision for loosening was 2% at 5 years, 5% at 10 years, and 7% at 15 years. Femoral (HR, 5.0; p = 0.04) and tibial (HR, 6.7; p < 0.01) bone-grafting at reimplantation were predictive of aseptic failure. The most common complications were wound-healing issues, requiring reoperation in 12 (5%) of the knees. The rate of death at 2 years following reimplantation was 11%. The mean KSS improved from 45 at PJI diagnosis to 76 at 10 years following reimplantation (p < 0.01). Conclusions: Long-term reinfection rates following 2-stage exchange for PJI after total knee arthroplasty were similar to those of shorter-term reports and were maintained out to 15 years. Mechanical failure rates were low if bone loss was addressed at the time of reimplantation. Improvements in clinical outcomes were maintained at long-term follow-up. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Abstract Tumor cells are able to evade cytotoxic therapies through the accumulation of genomic mutations and rapid evolution. In the case of oncolytic virotherapy, understanding the mechanisms by which cancer cells develop resistance to infection and lysis is critical to the development of more effective viral-based platforms. Here, we identify APOBEC3 as an important factor involved in the restriction of vesicular stomatitis virus (VSV). We show that VSV infection of B16 murine melanoma cells upregulated APOBEC3 in an IFNβ-dependent manner, which was responsible for the evolution of virus-resistanT-cell populations and suggested that APOBEC3 expression promoted the acquisition of a virus-resistant phenotype. ShRNA knockdown of APOBEC3 in B16 cells diminished their capacity to develop resistance to VSV infection in vitro, and enhanced the therapeutic effect of VSV in vivo. Similarly, overexpression of human APOBEC3B promoted the acquisition of resistance to oncolytic VSV in murine melanoma and glioblastoma lines, as well as in a human melanoma cell line in vitro and in vivo. Finally, we demonstrate that progeny virus obtained after passage through APOBEC3B overexpressing cells contained more defective interfering particles, thereby indicating that APOBEC3B directly affected the fitness of VSV, an RNA virus that has not previously been identified to be restricted by APOBEC3B. This research identifies APOBEC3 enzymes as key players to target in order to improve the efficacy of oncolytic viruses as well as broader nucleic acid-based therapeutic platforms. Citation Format: Amanda L. Huff, Phonphimon Wongthida, Timothy Kottke, Jill Thompson, Christopher B. Driscoll, Matthew Schuelke, Kevin G. Shim, Reuben S. Harris, Amy Molan, Jose S. Pulido, Peter J. Selby, Kevin J. Harrington, Alan Melcher, Laura Evgin, Richard Vile. APOBEC3 confers resistance to oncolytic VSV therapy [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A133.

Background. Underutilization of marginal-quality kidneys for transplantation produced ideas of expediting kidney placement for populations with decreased opportunities of receiving transplants. Such policies can be less efficacious for specific individuals and should be scrutinized until the decision-making for accepting marginal-quality organs, which has relied on experiential judgment, is better understood at the individual level. There exist rigorous tools promoting personalized decisions with useful and objective information. Methods. This article introduces a decision-tree methodology that analyzes a patient’s dilemma: to accept a kidney offer now or reject it. The methodology calculates the survival benefit of accepting a kidney given a certain quality now and the survival benefit of rejecting it. Survival benefit calculation accounts for patients’ and donors’ characteristics and transplant centers’ and organ procurement organizations’ performances and incorporates patients’ perceived transplant and dialysis utilities. Valuations of rejecting an offer are contingent on future opportunities and subject to uncertainty in the timing of successive kidney offers and their quality and donor characteristics. Results. The decision tree was applied to a realistic patient profile as a demonstration. The tool was tested on 1000 deceased-donor kidney offers in 2016. Evaluating up to 1 year of future offers, the tool attains 61% accuracy, with transplant utility of 1.0 and dialysis utility of 0.5. The accuracy reveals potential bias in kidney offer acceptance/rejection at transplant centers. Conclusions. The decision-tree tool presented could aid personalized transplant decision-making in the future by providing patients with calculated, individualized survival benefits between accepting and rejecting a kidney offer.

Aims Concurrent hip and spine pathologies can alter the biomechanics of spinopelvic mobility in primary total hip arthroplasty (THA). This study examines how differences in pelvic orientation of patients with spine fusions can increase the risk of dislocation risk after THA. Patients and Methods We identified 84 patients (97 THAs) between 1998 and 2015 who had undergone spinal fusion prior to primary THA. Patients were stratified into three groups depending on the length of lumbar fusion and whether or not the sacrum was involved. Mean age was 71 years (40 to 87) and 54 patients (56%) were female. The mean body mass index (BMI) was 30 kg/m2 (19 to 45). Mean follow-up was six years (2 to 17). Patients were 1:2 matched to patients with primary THAs without spine fusion. Hazard ratios (HR) were calculated. Results Dislocation in the fusion group was 5.2% at one year versus 1.7% in controls but this did not reach statistical significance (HR 1.9; p = 0.33). Compared with controls, there was no significant difference in rate of dislocation in patients without a sacral fusion. When the sacrum was involved, the rate of dislocation was significantly higher than in controls (HR 4.5; p = 0.03), with a trend to more dislocations in longer lumbosacral fusions. Patient demographics and surgical characteristics of THA (i.e. surgical approach and femoral head diameter) did not significantly impact risk of dislocation (p > 0.05). Significant radiological differences were measured in mean anterior pelvic tilt between the one-level lumbar fusion group (22°), the multiple-level fusion group (27°), and the sacral fusion group (32°; p < 0.01). Ten-year survival was 93% in the fusion group and 95% in controls (HR 1.2; p = 0.8). Conclusion Lumbosacral spinal fusions prior to THA increase the risk of dislocation within the first six months. Fusions involving the sacrum with multiple levels of lumbar involvement notably increased the risk of postoperative dislocation compared with a control group and other lumbar fusions. Surgeons should take care with component positioning and may consider higher stability implants in this high-risk cohort.

Introduction: Cerebral small-vessel disease (SVD) is associated with increased stroke risk and poor stroke outcomes. We aimed to evaluate if chronic SVD burden is associated with poor recruitment of collaterals in large-vessel occlusive stroke. Methods: Consecutive patients with MCA±ICA occlusion presenting within 6 hours after stroke symptoms onset from 2012- 2016 were included. Primary outcome was collateral flow, which was assessed on baseline CT-angiogram (poor ≤50% filling, good >50% filling). Markers of chronic SVD on brain MRI were rated for the presence of WMH (Fazekas scale 2-3), enlarged perivascular spaces (EPVS), chronic lacunae, and any cerebral microbleeds (CMB) using the STRIVE criteria. Severity of SVD was quantified by adding the presence of each SVD feature to a maximum score of 4. Multivariable logistic regression models were performed to evaluate the relationships between SVD and poor collaterals. Results: Of the 100 patients, the mean age was 65±16, median NIHSS was 15, and 68% had SVD. Poor collaterals were observed in 46%, and those with SVD were more likely to have poor collaterals (aOR 1.9; 95%CI 1.1-3.2) than patients without SVD. Of the SVD types, poor collaterals were associated with WMH (aOR 2.9 per Fazekas increment; 95%CI 1.6-5.3) but not EPVS (aOR 1.3; 0.4-4.0), lacunae (aOR 2.1; 0.6-7.1), or CMB (aOR 2.1; 0.6-7.8). Having a greater number of different SVD markers was associated with a higher odds of poor collaterals (crude trend p<.001; adjusted p=.056). There was a dose-dependent relationship between WMH burden and poor collaterals: adjusted odds of poor collaterals were 1.5, 3.0, and 9.7 across Fazekas scores of 1-3 (trends P=.015, Table). No patient with SVD score of 4 had good collaterals. Conclusions: Chronic cerebral small-vessel disease is associated with poor recruitment of collaterals in large-vessel occlusive stroke. A prospective study to elucidate the mechanism of how SVD may impair the recruitment of collaterals is ongoing.