The Characteristics and Outcomes of Native Aortic Valve Thrombosis: A Systematic Review.

BACKGROUND: There is a lack of knowledge in the current medical literature about native aortic valve thrombosis. OBJECTIVES: The aim of this systematic review was to summarize the characteristics, presentations, underlying etiologies, and outcomes of native aortic valve thrombosis and to present a meta-analysis of the best available data. METHODS: The authors performed a literature search, identified published cases of patients with native aortic valve thrombosis, and pooled the data in this meta-analysis. The statistical analysis included calculations of the prevalence of the various presentations, underlying etiologies, aortic cusp involvement, as well as choices of diagnostic testing. They calculated the sensitivities of the various diagnostic testing as well as in-hospital mortality event rates and the univariate ORs of the risk factors for poor outcomes. RESULTS: The search strategy and screening process yielded 74 cases of native aortic valve thrombosis, which are included in this meta-analysis. The data revealed that the most common presentation was myocardial infarction in 36%, and the most common underlying etiology was hypercoagulable state in 30%. In-hospital clinical deterioration after presentation including recurrent embolism occurred in ∼38%, and in-hospital mortality rate was ∼20%. CONCLUSIONS: Native aortic valve thrombosis is clinically relevant, especially in patients presenting with embolic events. Awareness about native aortic valve or root thrombosis as well as its underlying etiologies, diagnostic work-up, and management is essential, because this condition can be associated with poor outcomes.

The Electrocardiogram: Still a Useful Tool in the Primary Care Office.

A 12-lead electrocardiogram (ECG) is the most commonly ordered cardiac test. Although data are not robust, guidelines recommend against performing an ECG in patients who are asymptomatic, even if they have a higher risk of developing cardiovascular disease in the long term. Conversely, patients with cardiac symptoms, including chest pain, dyspnea, palpitation, and syncope, should have an ECG performed in the office. Computerized algorithms exist ubiquitously to guide interpretation, but they can be the source of erroneous information. A stepwise approach is given to guide the primary care physician's approach to the systematic interpretation of ECG tracings.

Impact of residual coronary atherosclerosis on transfemoral transcatheter aortic valve replacement.

OBJECTIVES: This study reports on the clinical effects of complete vs incompletely revascularized coronary artery disease on transcatheter aortic valve replacement (TAVR). BACKGROUND: There is a high prevalence of active coronary artery disease (CAD) in patients undergoing TAVR but preemptive revascularization remains controversial. METHODS: Patients were categorized into three cohorts: complete revascularization (CR), incomplete revascularization of a major epicardial artery (IR Major), and incomplete revascularization of a minor epicardial artery only (IR Minor). When feasible, SYNTAX scoring was performed for exploratory analysis. Analyses were performed using Cox proportional hazard models and Kaplan-Meier method. RESULTS: A total of 323 patients with active CAD were included. Adjusted outcomes showed that patients with IR Major had increased incidence of acute myocardial infarction (AMI) or revascularization compared with those in the CR cohort (HR 3.72, P = 0.048). No difference was noted in all-cause mortality or all-cause readmission rates. Exploratory secondary analysis with residual SYNTAX scores showed a significant interaction between disease burden and AMI/revascularization, as well as all-cause readmission. All-cause mortality remained unaffected based on residual SYNTAX scores. CONCLUSIONS: This is a retrospective single-center study reporting on pre-TAVR revascularization outcomes in patients with active CAD. In this analysis, we found that patients undergoing TAVR benefited from achieving complete revascularization to abate future incidence of AMI/revascularization. Despite this finding, all-cause mortality remained unaffected. Future efforts should focus on the role of functional assessment of the coronaries, as well as the long-term effects of complete revascularization in a larger patient cohort.

Sigma-2 receptor agonist derivatives of 1-Cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)propyl]piperazine (PB28) induce cell death via mitochondrial superoxide production and caspase activation in pancreatic cancer.

BACKGROUND: Despite considerable efforts by scientific research, pancreatic cancer is the fourth leading cause of cancer related mortalities. Sigma-2 receptors, which are overexpressed in several tumors, represent promising targets for triggering selective pancreatic cancer cells death. METHODS: We selected five differently structured high-affinity sigma-2 ligands (PB28, PB183, PB221, F281 and PB282) to study how they affect the viability of diverse pancreatic cancer cells (human cell lines BxPC3, AsPC1, Mia PaCa-2, and Panc1 and mouse Panc-02, KCKO and KP-02) and how this is reflected in vivo in a tumor model. RESULTS: Important cytotoxicity was shown by the compounds in the aggressive Panc02 cells, where cytotoxic activity was caspase-3 independent for four of the five compounds. However, both cytotoxicity and caspase-3 activation involved generation of Reactive Oxygen Species (ROS), which could be partially reverted by the lipid antioxidant α-tocopherol, but not by the hydrophilic N-acetylcysteine (NAC) indicating crucial differences in the intracellular sites exposed to oxidative stress induced by sigma-2 receptor ligands. Importantly, all the compounds strongly increased the production of mitochondrial superoxide radicals except for PB282. Despite a poor match between in vitro and the in vivo efficacy, daily treatment of C57BL/6 mice bearing Panc02 tumors resulted in promising effects with PB28 and PB282 which were similar compared to the current standard-of-care chemotherapeutic gemcitabine without showing signs of systemic toxicities. CONCLUSIONS: Overall, this study identified differential sensitivities of pancreatic cancer cells to structurally diverse sigma-2 receptor ligands. Of note, we identified the mitochondrial superoxide pathway as a previously unrecognized sigma-2 receptor-activated process, which encourages further studies on sigma-2 ligand-mediated cancer cell death for the targeted treatment of pancreatic tumors.

A telephone call 1 week after hospitalization can identify risk factors for vascular surgery readmission.

OBJECTIVE: Compared with other populations, patients who undergo vascular surgery have higher 30-day hospital readmission rates of up to 25%. Postdischarge telephone call assessments have demonstrated utility in patients with significant medical comorbidities and traditionally high readmission rates. Therefore, we hypothesized that a 1-week postdischarge telephone call evaluation can identify risk factors for readmission among vascular surgery patients. METHODS: Patients who underwent a vascular surgery procedure during a 1-year period by a single vascular surgeon at one hospital received a postdischarge telephone call questionnaire to review postoperative pain, surgical site, constitutional symptoms, and follow-up arrangement. The primary outcome measure was frequency of postoperative symptoms as collected on the telephone call questionnaire. The secondary outcome measure was 30-day hospital readmission rates. RESULTS: Among 167 patients, 131 (78%) received a telephone call after discharge. Calls identified pain relieved by prescription medication (odds ratio, 6.67; confidence interval, 0.82-53.81; P = .05) and continued dressing application (odds ratio, 9.55; confidence interval, 0.54-166.6; P = .04) as risk factors for 30-day readmission. The 30-day readmission was not statistically different in patients who were successfully and not successfully contacted with a postdischarge telephone call (8% and 17%, respectively; P = .37). CONCLUSIONS: Vascular surgery patients are at higher risk of 30-day readmission than are patients in other surgical subspecialties. For the majority of patients, implementing a 1-week postdischarge telephone call for short-term follow-up evaluation is feasible and can help identify potential risk factors for hospital readmission within 30 days.

Targeted pancreatic cancer therapy with the small molecule drug conjugate SW IV-134.

Pancreatic adenocarcinoma is highly resistant to conventional therapeutics and has been shown to evade apoptosis by deregulation of the X-linked and cellular inhibitors of apoptosis proteins (XIAP and cIAP). Second mitochondria-derived activator of caspases (Smac) induces and amplifies cell death by reversing the anti-apoptotic activity of IAPs. Thus, Smac-derived peptide analogues (peptidomimetics) have been developed and shown to represent promising cancer therapeutics. Sigma-2 receptors are overexpressed in many proliferating tumor cells including pancreatic cancer. Selected ligands to this receptor are rapidly internalized by cancer cells. These characteristics have made the sigma-2 receptor an attractive target for drug delivery because selective delivery to cancer cells has the potential to increase therapeutic efficacy while minimizing toxicity to normal tissues. Here, we describe the initial characterization of SW IV-134, a chemically linked drug conjugate between the sigma-2 ligand SW43 and the Smac mimetic SW IV-52 as a novel treatment option for pancreatic adenocarcinoma. The tumor killing characteristics of our dual-domain therapeutic SW IV-134 was far greater than either component in isolation or in an equimolar mix and suggests enhanced cellular delivery when chemically linked to the sigma-2 ligand. One of the key findings was that SW IV-134 retained target selectivity of the Smac cargo with the involvement of the NF-κB/TNFα signaling pathway. Importantly, SW IV-134 slowed tumor growth and improved survival in murine models of pancreatic cancer. Our data support further study of this novel therapeutic and this drug delivery strategy because it may eventually benefit patients with pancreatic cancer.

A phase I study of IMP321 and gemcitabine as the front-line therapy in patients with advanced pancreatic adenocarcinoma.

PURPOSE: This phase I study was conducted to determine the safety profile and maximum tolerated dose (MTD) of IMP321, a soluble lymphocyte activation gene-3 (LAG-3) Ig fusion protein and MHC Class II agonist, combined with gemcitabine in patients with advanced pancreatic adenocarcinoma. PATIENTS AND METHODS: Patients with advanced pancreatic adenocarcinoma were treated with gemcitabine (1,000 mg/m(2))(level 1), gemcitabine (1,000 mg/m(2)) plus IMP 321 at 0.5 mg (level 2) and 2.0 mg (level 3), respectively. Safety, toxicity, and immunological markers at baseline and post treatment were assessed. RESULTS: A total of 18 patients were enrolled to the study, and 17 were evaluable for toxicity. None of the 6 patients who received 0.5 mg IMP321 experienced IMP321-related adverse events. Of the 5 patients who received IMP321 at the 2 mg dose level, 1 experienced rash, 1 reported hot flashes and 2 had mild pain at the injection sites. No severe adverse events previously attributed to IMP321 were observed. No significant differences were observed when comparing pre- and post-treatment levels of monocytes (CD11b+CD14+), conventional dendritic cells (CD11c+) or T cell subsets (CD4, CD8). CONCLUSIONS: IMP321 in combination with gemcitabine is a well-tolerated regimen. IMP321 did not result in any severe adverse events. No incremental activity observed for the additional IMP 321 to gemcitabine at the dose levels evaluated, likely due to sub-optimal dosing. Immunological markers suggested that higher dose levels of IMP321 are needed for future clinical studies.

Therapeutic targeting of pancreatic cancer utilizing sigma-2 ligands.

One major barrier in the development of pancreas cancer therapeutics is the selective delivery of the drugs to their cellular targets. We have previously developed several sigma-2 ligands and reported the discovery of a component of the receptor for these ligands. Several sigma-2 ligands have been shown to trigger apoptosis in pancreas cancer cells. More importantly, sigma-2 ligands are internalized rapidly by the cancer cells and are capable of delivering other small-molecule therapeutics. Here we review sigma-2 ligands and conjugates as a potential novel therapy suitable for investigation in patients with pancreatic cancer.

Lysosomal membrane permeabilization is an early event in Sigma-2 receptor ligand mediated cell death in pancreatic cancer.

BACKGROUND: Sigma-2 receptor ligands have been studied for treatment of pancreatic cancer because they are preferentially internalized by proliferating cells and induce apoptosis. This mechanism of apoptosis is poorly understood, with varying reports of caspase-3 dependence. We evaluated multiple sigma-2 receptor ligands in this study, each shown to decrease tumor burden in preclinical models of human pancreatic cancer. RESULTS: Fluorescently labeled sigma-2 receptor ligands of two classes (derivatives of SW43 and PB282) localize to cell membrane components in Bxpc3 and Aspc1 pancreatic cancer cells and accumulate in lysosomes. We found that interactions in the lysosome are critical for cell death following sigma-2 ligand treatment because selective inhibition of a protective lysosomal membrane glycoprotein, LAMP1, with shRNA greatly reduced the viability of cells following treatment. Sigma-2 ligands induced lysosomal membrane permeabilization (LMP) and protease translocation triggering downstream effectors of apoptosis. Subsequently, cellular oxidative stress was greatly increased following treatment with SW43, and the hydrophilic antioxidant N-acetylcysteine (NAC) gave greater protection against this than a lipophilic antioxidant, α-tocopherol (α-toco). Conversely, PB282-mediated cytotoxicity relied less on cellular oxidation, even though α-toco did provide protection from this ligand. In addition, we found that caspase-3 induction was not as significantly inhibited by cathepsin inhibitors as by antioxidants. Both NAC and α-toco protected against caspase-3 induction following PB282 treatment, while only NAC offered protection following SW43 treatment. The caspase-3 inhibitor DEVD-FMK offered significant protection from PB282, but not SW43. CONCLUSIONS: Sigma-2 ligand SW43 commits pancreatic cancer cells to death by a caspase-independent process involving LMP and oxidative stress which is protected from by NAC. PB282 however undergoes a caspase-dependent death following LMP protected by DEVD-FMK and α-toco, which is also known to stabilize the mitochondrial membrane during apoptotic stimuli. These differences in mechanism are likely dependent on the structural class of the compounds versus the inherent sigma-2 binding affinity. As resistance of pancreatic cancers to specific apoptotic stimuli from chemotherapy is better appreciated, and patient-tailored treatments become more available, ligands with high sigma-2 receptor affinity should be chosen based on sensitivities to apoptotic pathways.

Use of multifunctional sigma-2 receptor ligand conjugates to trigger cancer-selective cell death signaling.

One major challenge in the development of cancer therapeutics is the selective delivery of the drugs to their cellular targets. In the case of pancreatic cancer, the σ-2 receptor is a unique target that triggers apoptosis upon activation. We have previously developed a series of chemical compounds with high affinity for the σ-2 receptor and showed rapid internalization of the ligands. One particular specific ligand of the σ-2 receptor, SV119, binds to pancreatic cancer cells and induces target cell death in vitro and in vivo. In this study, we characterized the ability of SV119 to selectively deliver other death-inducing cargos to augment the cytotoxic properties of SV119 itself. When conjugated to SV119, small molecules that are known to interfere with intracellular prosurvival pathways retained their ability to induce cell death, the efficiency of which was enhanced by the combinatorial effect of SV119 delivered with its small molecule cargo. Our findings define a simple platform technology to increase the tumor-selective delivery of small molecule therapeutics via σ-2 ligands, permitting chemotherapeutic synergy that can optimize efficacy and patient benefit.

A single-institution review of 157 patients presenting with benign and malignant tumors of the ampulla of Vater: management and outcomes.

BACKGROUND: Although benign ampullary tumors are removed endoscopically, due to their potential to progress to malignant disease, the favored treatment for adenocarcinoma is pancreaticoduodenectomy. We reviewed our institution's experience in order to identify which patients were at highest risk of disease progression following surgical resection, as well as evaluate whether localized T1 tumors are best treated by pancreaticoduodenectomy. METHODS: We retrospectively reviewed 157 patients who presented with an ampullary mass, from 2001 to 2010, and identified 51 with benign adenoma and 106 with adenocarcinoma. RESULTS: Patients with malignant tumors most often presented with larger tumors and jaundice, which alone was predictive of survival (OR = 67). Forty-five percent of patients with pathologically confirmed T1 tumors had positive lymph nodes and median survival was modest at 60 months. Lymph node involvement was predictive of recurrence and decreased survival. CONCLUSION: Patients with malignant tumors often present with jaundice and larger tumors. These findings should warrant suspicion for cancer and expedited preoperative workup. Based on our finding that nearly half the patients with T1 tumors had positive lymph nodes, we recommend pancreaticoduodenectomy for any patient with biopsy proven adenocarcinoma who is a suitable candidate for surgery.

Fluorescent derivatives of σ receptor ligand 1-cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)propyl]piperazine (PB28) as a tool for uptake and cellular localization studies in pancreatic tumor cells.

Fluorescent derivatives of σ(2) high affinity ligand 1-cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)propyl]piperazine 1 (PB28) were synthesized. NBD or dansyl fluorescent tags were connected through a 5- or 6-atom linker in two diverse positions of 1 structure. Good σ(2) affinities were obtained when the fluorescent tag was linked to 5-methoxytetralin nucleus replacing the methyl function. NBD-bearing compound 16 displayed high σ(2) affinity (K(i) = 10.8 nM) and optimal fluorescent properties. Its uptake in pancreatic tumor cells was evaluated by flow cytometry, showing that it partially occurs through endocytosis. In proliferating cells, the uptake was higher supporting that σ(2) receptors are markers of cell proliferation and that the higher the proliferation is, the stronger the antiproliferative effect of σ(2) agonists is. Colocalization of 16 with subcellular organelles was studied by confocal microscopy: the greatest was in endoplasmic reticulum and lysosomes. Fluorescent σ(2) ligands show their potential in clarifying the mechanisms of action of σ(2) receptors.

The novel sigma-2 receptor ligand SW43 stabilizes pancreas cancer progression in combination with gemcitabine.

BACKGROUND: Sigma-2 receptors are over-expressed in proliferating cancer cells, making an attractive target for the targeted treatment of pancreatic cancer. In this study, we investigated the role of the novel sigma-2 receptor ligand SW43 to induce apoptosis and augment standard chemotherapy. RESULTS: The binding affinity for sigma-2 ligands is high in pancreas cancer, and they induce apoptosis with a rank order of SV119 < SW43 < SRM in vitro. Combining these compounds with gemcitabine further increased apoptosis and decreased viability. Our in vivo model showed that sigma-2 ligand treatment decreased tumor volume to the same extent as gemcitabine. However, SW43 combination treatment with gemcitabine was superior to the other compounds and resulted in stabilization of tumor volume during treatment, with minimal toxicities. CONCLUSIONS: This study shows that the sigma-2 ligand SW43 has the greatest capacity to augment gemcitabine in a pre-clinical model of pancreas cancer and has provided us with the rationale to move this compound forward with clinical investigations for patients with pancreatic cancer.

Elucidating the role of Trp105 in the KPC-2 ß-lactamase.

The molecular basis of resistance to ß-lactams and ß-lactam-ß-lactamase inhibitor combinations in the KPC family of class A enzymes is of extreme importance to the future design of effective ß-lactam therapy. Recent crystal structures of KPC-2 and other class A ß-lactamases suggest that Ambler position Trp105 may be of importance in binding ß-lactam compounds. Based on this notion, we explored the role of residue Trp105 in KPC-2 by conducting site-saturation mutagenesis at this position. Escherichia coli DH10B cells expressing the Trp105Phe, -Tyr, -Asn, and -His KPC-2 variants possessed minimal inhibitory concentrations (MICs) similar to E. coli cells expressing wild type (WT) KPC-2. Interestingly, most of the variants showed increased MICs to ampicillin-clavulanic acid but not to ampicillin-sulbactam or piperacillin-tazobactam. To explain the biochemical basis of this behavior, four variants (Trp105Phe, -Asn, -Leu, and -Val) were studied in detail. Consistent with the MIC data, the Trp105Phe ß-lactamase displayed improved catalytic efficiencies, k(cat)/K(m), toward piperacillin, cephalothin, and nitrocefin, but slightly decreased k(cat)/K(m) toward cefotaxime and imipenem when compared to WT ß-lactamase. The Trp105Asn variant exhibited increased K(m)s for all substrates. In contrast, the Trp105Leu and -Val substituted enzymes demonstrated notably decreased catalytic efficiencies (k(cat)/K(m)) for all substrates. With respect to clavulanic acid, the K(i)s and partition ratios were increased for the Trp105Phe, -Asn, and -Val variants. We conclude that interactions between Trp105 of KPC-2 and the ß-lactam are essential for hydrolysis of substrates. Taken together, kinetic and molecular modeling studies define the role of Trp105 in ß-lactam and ß-lactamase inhibitor discrimination.

Substrate selectivity and a novel role in inhibitor discrimination by residue 237 in the KPC-2 beta-lactamase.

Beta-lactamase-mediated antibiotic resistance continues to challenge the contemporary treatment of serious bacterial infections. The KPC-2 beta-lactamase, a rapidly emerging gram-negative resistance determinant, hydrolyzes all commercially available beta-lactams, including carbapenems and beta-lactamase inhibitors; the amino acid sequence requirements responsible for this versatility are not yet known. To explore the bases of beta-lactamase activity, we conducted site saturation mutagenesis at Ambler position 237. Only the T237S variant of the KPC-2 beta-lactamase expressed in Escherichia coli DH10B maintained MICs equivalent to those of the wild type (WT) against all of the beta-lactams tested, including carbapenems. In contrast, the T237A variant produced in E. coli DH10B exhibited elevated MICs for only ampicillin, piperacillin, and the beta-lactam-beta-lactamase inhibitor combinations. Residue 237 also plays a novel role in inhibitor discrimination, as 11 of 19 variants exhibit a clavulanate-resistant, sulfone-susceptible phenotype. We further showed that the T237S variant displayed substrate kinetics similar to those of the WT KPC-2 enzyme. Consistent with susceptibility testing, the T237A variant demonstrated a lower k(cat)/K(m) for imipenem, cephalothin, and cefotaxime; interestingly, the most dramatic reduction was with cefotaxime. The decreases in catalytic efficiency were driven by both elevated K(m) values and decreased k(cat) values compared to those of the WT enzyme. Moreover, the T237A variant manifested increased K(i)s for clavulanic acid, sulbactam, and tazobactam, while the T237S variant displayed K(i)s similar to those of the WT. To explain these findings, a molecular model of T237A was constructed and this model suggested that (i) the hydroxyl side chain of T237 plays an important role in defining the substrate profile of the KPC-2 beta-lactamase and (ii) hydrogen bonding between the hydroxyl side chain of T237 and the sp(2)-hybridized carboxylate of imipenem may not readily occur in the T237A variant. This stringent requirement for selected cephalosporinase and carbapenemase activity and the important role of T237 in inhibitor discrimination in KPC-2 are central considerations in the future design of beta-lactam antibiotics and inhibitors.

Loss of p53, rather than beta-catenin overexpression, induces survivin-mediated resistance to apoptosis in an esophageal cancer cell line.

OBJECTIVE: Survivin, an important inhibitor of apoptosis, is overexpressed in esophageal cancer and negatively affects survival. The complex regulation of survivin transcription involves enhancement by beta-catenin and repression by p53. The purpose of this study is to test whether inhibition of beta-catenin or overexpression of p53 can decrease survivin expression and render esophageal cancer cells more susceptible to apoptosis. METHODS: Studies were performed in normal human esophageal epithelial cells and the human esophageal cancer cell line TE7. Levels of beta-catenin, survivin, and p53 were measured by Western blot. Apoptosis was induced after treatment with camptothecin and measured by release of caspase 3 and morphologic criteria. The roles of survivin and beta-catenin in preventing apoptosis were tested by their silencing with specific small interfering RNA molecules. The effect of p53 overexpression on survivin promoter activity was measured using a survivin promoter-luciferase reporter construct and by real-time polymerase chain reaction measurement of survivin mRNA levels. RESULTS: Both beta-catenin and survivin are overexpressed in TE7 cells, whereas p53 expression is negligible. TE7 cells demonstrate resistance to camptothecin-induced apoptosis (P < .01). This effect is significantly reduced by inhibition of survivin, but not of beta-catenin (P < .01). Overexpression of p53 in TE7 cells reduces survivin transcription and mRNA levels (P < .01), without reducing survivin protein levels. CONCLUSION: Survivin plays a critical role in TE7 cell resistance to camptothecin-induced apoptosis. This effect is not dependent on beta-catenin expression. Overexpression of p53 decreases survivin transcription but does not decrease levels of survivin protein, suggesting posttranscriptional control of survivin expression.