The Combination of TIM3-Based Checkpoint Blockade and Oncolytic Virotherapy Regresses Established Solid Tumors.

T-cell immunoglobulin and mucin domain 3 (TIM3) is emerging as a potential target for antibody-based checkpoint blockade. However, the efficacy of TIM3 blockade in combination with other treatment modalities, has not been extensively studied. In the current work we combined TIM3 blockade with myxoma virus-based oncolytic virotherapy (OV). Our results demonstrate that myxoma virus's ability to initiate an immense antitumor immune response complements the ability of TIM3 blockade to shift the tumor microenvironment to a more proinflammatory state. As a result, the combination of TIM3 blockade and OV is able to completely eradicate established disease, while neither monotherapy is effective. These data represent the first demonstration that OV can enhance the efficacy of TIM3 blockade and suggest that this treatment may need to be incorporated into more aggressive, combinatorial regimens in order to fulfill its potential as an immunotherapeutic.

Monitoring Therapeutic Responses to Silicified Cancer Cell Immunotherapy Using PET/MRI in a Mouse Model of Disseminated Ovarian Cancer.

Current imaging approaches used to monitor tumor progression can lack the ability to distinguish true progression from pseudoprogression. Simultaneous metabolic 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) positron emission tomography (PET) and magnetic resonance imaging (MRI) offers new opportunities to overcome this challenge by refining tumor identification and monitoring therapeutic responses to cancer immunotherapy. In the current work, spatial and quantitative analysis of tumor burden were performed using simultaneous [18F]FDG-PET/MRI to monitor therapeutic responses to a novel silicified cancer cell immunotherapy in a mouse model of disseminated serous epithelial ovarian cancer. Tumor progression was validated by bioluminescence imaging of luciferase expressing tumor cells, flow cytometric analysis of immune cells in the tumor microenvironment, and histopathology. While PET demonstrated the presence of metabolically active cancer cells through [18F]FDG uptake, MRI confirmed cancer-related accumulation of ascites and tissue anatomy. This approach provides complementary information on disease status without a confounding signal from treatment-induced inflammation. This work provides a possible roadmap to facilitate accurate monitoring of therapeutic responses to cancer immunotherapies.

Decreasing the Susceptibility of Malignant Cells to Infection Does Not Impact the Overall Efficacy of Myxoma Virus-Based Oncolytic Virotherapy.

Oncolytic virotherapy relies on the induction of anti-tumor immune responses to achieve therapeutic efficacy. The factors that influence the induction of these responses, however, are not well understood. To begin to address this lack of knowledge, we asked how decreasing the susceptibility of malignant cells to direct viral infection would impact the induction of immune responses and therapeutic efficacy caused by oncolytic myxoma virus treatment. To accomplish this, we used CRISPR-Cas9 genome editing to remove the essential sulfation enzyme N-deacetylase/N-sulfotransferase-1 from B16/F10 murine melanoma cells. This eliminates the negative cell surface charges associated with glycosaminoglycan sulfation, which reduces a cell's susceptibility to infection with the myxoma virus by ∼3- to 10-fold. With the use of these cells as a model of reduced susceptibility to oncolytic infection, our data demonstrate that 3- to 10-fold reductions in in vivo infection do not hinder the ability of the oncolytic myxoma virus to induce anti-tumor immunity and do not lower the overall efficacy of localized treatment. Additionally, our data show that in mice bearing multiple distinct tumor masses, the choice to treat a less-susceptible tumor mass does not reduce the overall therapeutic impact against either the injected or noninjected lesion. Taken together, these data suggest that minor changes in the susceptibility of malignant cells to direct oncolytic infection do not necessarily influence the overall outcomes of treatment.

Initial dose of oncolytic myxoma virus programs durable antitumor immunity independent of in vivo viral replication.

BACKGROUND: Oncolytic therapy uses live-replicating viruses to improve the immunological status of treated tumors. Critically, while these viruses are known to self-amplify in vivo, clinical oncolytic therapies still appear to display a strong dose dependence and the mechanisms mediating this dose dependence are not well understood. METHODS: To explore this apparent contradiction, we investigated how the initial dose of oncolytic myxoma virus affected the subsequent ability of treatment to alter the immunological status of tumors as well as synergize with programmed cell death protein 1 (PD1) blockade. RESULTS: Our results indicate that, due to viral self-amplification in vivo, the overall load of myxoma virus rapidly normalizes within treated tumors despite up to 3-log differences in inoculating dose. Because of this, therapeutic efficacy in the absence of checkpoint blockade is largely dose independent. Despite this rapid normalization, however, treatment with high or low doses of myxoma virus induces distinct immunological changes within treated tumors. Critically, these changes appear to be durably programmed based on the initial oncolytic dose with low-dose treatment failing to induce immunological improvements despite rapidly achieving equivalent viral burdens. Finally, due to the distinct immunological profiles induced by high and low myxoma virus doses, oncolytic efficacy resulting from combination with PD1 blockade therapy displays a strong dose dependence. CONCLUSIONS: Taken together, these data suggest that the ability of oncolytic myxoma virus to immunologically reprogram treated tumors is dependent on initial viral dose. Additionally, this work could provide a possible mechanistic explanation for clinical results observed with other oncolytic viruses.

Reduced cellular binding affinity has profoundly different impacts on the spread of distinct poxviruses.

Poxviruses are large enveloped viruses that replicate exclusively in the cytoplasm. Like all viruses, their replication cycle begins with virion adsorption to the cell surface. Unlike most other viral families, however, no unique poxviral receptor has ever been identified. In the absence of a unique receptor, poxviruses are instead thought to adhere to the cell surface primarily through electrostatic interactions between the positively charged viral envelope proteins and the negatively charged sulfate groups on cellular glycosaminoglycans (GAGs). While these negatively charged GAGs are an integral part of all eukaryotic membranes, their specific expression and sulfation patterns differ between cell types. Critically, while poxviral binding has been extensively studied using virally centered genetic strategies, the impact of cell-intrinsic changes to GAG charge has never been examined. Here we show that loss of heparin sulfation, accomplished by deleting the enzyme N-Deacetylase and N-Sulfotransferase-1 (NDST1) which is essential for GAG sulfation, significantly reduces the binding affinity of both vaccinia and myxoma viruses to the cell surface. Strikingly, however, while this lowered binding affinity inhibits the subsequent spread of myxoma virus, it actually enhances the overall spread of vaccinia by generating more diffuse regions of infection. These data indicate that cell-intrinsic GAG sulfation plays a major role in poxviral infection, however, this role varies significantly between different members of the poxviridae.

Successful implantation of a Micra leadless pacemaker via collateral femoral vein and inferior vena cava filter.

This case details the successful implementation of a leadless pacemaker device in a patient with multiple venous occlusions and an IVC filter. As the incidence of IVC filters increases in patients with dysrhythmias, further investigations are required to determine the risk and safety of leadless pacemaker placement in this population.

Increased risk of mortality after lower extremity bypass in individuals with acute kidney injury in the Vascular Quality Initiative.

OBJECTIVE: The development of acute kidney injury (AKI) and its effect on prognosis after lower extremity bypass (LEB) surgery have not been well described. We determined risk factors associated with AKI in patients undergoing infrainguinal LEB surgery and whether individuals with AKI are at increased risk for cardiovascular events and mortality. METHODS: Data for 12,907 operations entered in the Vascular Quality Initiative (VQI) registry from January 2012 through April 2015 were retrospectively reviewed. Procedures performed on patients not on dialysis before the surgery with perioperative assessments of renal function were eligible for the study. AKI was defined as a postoperative increase in serum creatinine ≥0.5 mg/dL or new dialysis requirement. Logistic regression was performed to determine the effect of AKI on the risk of in-hospital cardiovascular events, including myocardial infarction, stroke, congestive heart failure, or arrhythmias, and mortality. Cox proportional hazards regression was performed to determine the risk of long-term mortality (median follow-up of 11.5 months). RESULTS: AKI developed after 507 (4%) of the 12,907 operations performed in 11,859 patients. After adjustment for demographic, clinical, and perioperative variables, AKI was associated with an increased risk of in-hospital cardiovascular events (odds ratio, 2.50; 95% confidence interval [CI], 1.91-3.28) and in-hospital mortality (odds ratio, 6.96; 95% CI, 3.94-12.31). Risk of mortality persisted over the course of follow-up (hazard ratio, 1.98; 95% CI, 1.58-2.47). CONCLUSIONS: AKI after LEB is associated with an increased risk of cardiovascular events and all-cause mortality. Further study should evaluate whether preoperative interventions before LEB can be effectively applied for at-risk patients to reduce the incidence of AKI and its associated morbidity and mortality.

Sinus of Valsalva Fistula to the Right Ventricle along with Coronary Artery Fistula to the Pulmonary Artery in a Young Native American Female.

Sinus of Valsalva aneurysm is a rare condition and associated with a high rate of mortality if rupture occurs. The aneurysms are rarely diagnosed until rupture occurs. This case describes a young Native American female whose only symptom was intermittent chest pain prior to the detection of the aneurysm along with a small ventricular septal defect. The patient was also found to have a coexisting coronary artery fistula, and it is rare phenomenon to have these coexisting anomalies. The anomalies were demonstrated on both cardiac computed tomography and coronary angiography. The patient underwent surgical closure of both anomalies, which is the recommended treatment to avoid future complications.

AP-7 into the nucleus accumbens disrupts acquisition but does not affect consolidation in a passive avoidance task.

The effect of the blockade of N-methyl-D-aspartic acid (NMDA)-type glutamatergic receptors in the nucleus accumbens septi (Acc) during different phases of a passive avoidance task (step-through paradigm, two chambers) of learning was studied in male rats which had been bilaterally cannulated into the Acc. Animals were trained with a punishment procedure (3 s shock of 1 mA) to avoid one of the chambers. The rats received either saline or (+/-)2-amino-7-phosphonoheptanoic acid (AP-7) solution (1 microg/1 microl) 10 min before training (pretraining schedule) or immediately after the shock (posttraining schedule). In the test phase, the animals were placed back into the white chamber after 1 and 8 days later. In this moment, rats stayed there for 1 min, after which the time elapsed between the removal of the door to the introduction into the dark chamber of the head (Latency 1) and body (Latency 2) and fecal boli expelled were recorded. In the pretraining injection schedule, the drug treatment significantly reduced Latency 2 (P<.05) and fecal boli (P<0.01) on Day 1, and all parameters on Day 8 (P<.05). The posttraining injection schedule did not modify behavior. We conclude that a preshock NMDA-glutamatergic blockade of the Acc leads to cognitive disturbances during acquisition and a decrease in anxiety levels, but that the consolidation of a learned task is not affected by postshock administration.

Effects of selective NMDA and non-NMDA blockade in the nucleus accumbens on the plus-maze test.

Effect of blocking N-methyl-D-aspartic acid (NMDA) and non-NMDA-glutamatergic receptors on performance in the plus-maze was studied in male rats bilaterally cannulated into the nucleus accumbens (Acc). Rats were divided into seven groups that received either 1 microl injections of saline, (+/-)2-amino-7-phosphonoheptanoic acid (AP-7, 0.2, 0.5, or 1 microg) or 2,3 dioxo-6-nitro-1,2,3,4,tetrahydrobenzo-(f)quinoxaline-7-sulphonamide disodium (NBQX, 0.2, 0.5, or 1 microg) 15 min before testing. Time spent in open arm, time per entry, end arrivals, open, closed, and total arm entries, relationship between open-, closed-, and total arm entries, rearing, face-, head-, and body grooming, and number of fecal boli were recorded. Time spent in the open arm increased under AP-7 (0.5 and 1 microg; P<.01) and NBQX (1 microg; P<.05) treatment, whereas time per entry was increased only with AP-7 (1 microg; P<.05). Open arm entries were increased by the intermediate doses of AP-7 (0.5 microg; P<.01) and NBQX (0.5 microg; P<.05); end arrivals were increased by the intermediate dose of AP-7 (0.5 microg/1 microl, P<.05). The frequency of rearing, grooming, and closed arm entries was not affected by the treatment. We conclude that NMDA and non-NMDA-glutamatergic blockade in the Acc lead to a behavioral disinhibition of cortical influences with the median doses, but that at higher doses the blockers have an anxiolytic-like effect.