Statins are powerful agents for the reduction of low-density lipoprotein cholesterol (LDL-C) and reduction of cardiovascular risk. Newly developed statins with increased potency, such as rosuvastatin (Crestor™) and NK-104 (in earlier clinical development), are capable of achieving marked LDL-C reductions. Cholesterol-lowering agents with mechanisms of action distinct from those of the statins are in active development. These include bile transport inhibitors, such as improved bile acid-absorbing resins and specific inhibitors of the ileal Na+/bile acid cotransporter. There are also specific inhibitors of cholesterol absorption, such as ezetimibe, which may provide cholesterol lowering that is additive to that achieved with statin treatment. Another approach is to reduce cardiovascular risk by modifying atherosclerotic processes within the arterial wall, as represented by the acyl CoA:cholesterol acyltransferase (ACAT) inhibitor avasimibe; ibe; ACAT inhibitors may reduce atherosclerotic lesions by inhibiting macrophage cholesterol storage.
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Daniel E. Forman;
Michael W. Rich;
Karen P. Alexander;
Susan Zieman;
Mathew S. Maurer;
Samer S. Najjar;
Joseph C. Cleveland;
Harlan M. Krumholz;
Nanette Wenger
Here, we report improved solubility and enhanced colonic delivery of reduced bromonoscapine (Red-Br-Nos), a cyclic ether brominated analogue of noscapine, upon encapsulation of its cyclodextrin (CD) complexes in bioresponsive guar gum microspheres (GGM). Phase-solubility analysis suggested that Red-Br-Nos complexed with β-CD and methyl-β-CD in a 1:1 stoichiometry, with a stability constant (Kc) of 2.29 × 103 M-1 and 4.27 × 103 M-1. Fourier transforms infrared spectroscopy indicated entrance of an O-CH2 or OCH3-C6H4-OCH3 moiety of Red-Br-Nos in the β-CD or methyl-β-CD cavity. Furthermore, the cage complex of Red-Br-Nos with β-CD and methyl-β-CD was validated by several spectral techniques. Rotating frame Overhauser enhancement spectroscopy revealed that the Ha proton of the OCH3-C6H4-OCH3 moiety was closer to the H5 proton of β-CD and the H3 proton of the methyl-β-CD cavity. The solubility of Red-Br-Nos in phosphate buffer saline (PBS, pH ∼ 7.4) was improved by ∼10.7-fold and ∼21.2-fold when mixed with β-CD and methyl-β-CD, respectively. This increase in solubility led to a favorable decline in the IC50 by ∼2-fold and ∼3-fold for Red-Br-Nos-β-CD-GGM and Red-Br-Nos-methyl-β-CD-GGM formulations respectively, compared to free Red-Br-Nos-β-CD and Red-Br-Nos-methyl-β-CD in human colon HT-29 cells. GGM-bearing drug complex formulations were found to be highly cytotoxic to the HT-29 cell line and further effective with simultaneous continuous release of Red-Br-Nos from microspheres. This is the first study to showing the preparation of drug-complex loaded GGMS for colon delivery of Red-Br-Nos that warrants preclinical assessment for the effective management of colon cancer.
Amyloids are self-perpetuating protein aggregates causing neurodegenerative diseases in mammals. Prions are transmissible protein isoforms (usually of amyloid nature). Prion features were recently reported for various proteins involved in amyloid and neural inclusion disorders. Heritable yeast prions share molecular properties (and in the case of polyglutamines, amino acid composition) with human disease-related amyloids. Fundamental protein quality control pathways, including chaperones, the ubiquitin proteasome system and autophagy are highly conserved between yeast and human cells. Crucial cellular proteins and conditions influencing amyloids and prions were uncovered in the yeast model. The treatments available for neurodegenerative amyloid-associated diseases are few and their efficiency is limited. Yeast models of amyloid-related neurodegenerative diseases have become powerful tools for high-throughput screening for chemical compounds and FDA-approved drugs that reduce aggregation and toxicity of amyloids. Although some environmental agents have been linked to certain amyloid diseases, the molecular basis of their action remains unclear. Environmental stresses trigger amyloid formation and loss, acting either via influencing intracellular concentrations of the amyloidogenic proteins or via heterologous inducers of prions. Studies of environmental and physiological regulation of yeast prions open new possibilities for pharmacological intervention and/or prophylactic procedures aiming on common cellular systems rather than the properties of specific amyloids.
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Kathleen M. Egan;
L. Burton Nabors;
Zachary J. Thompson;
Carrie M. Rozmeski;
Gabriella A. Anic;
Jeffrey Olson;
Renato V. LaRocca;
Sajeel A. Chowdhary;
Peter A. Forsyth;
Reid C. Thompson
Glioma and meningioma are uncommon tumors of the brain with few known risk factors. Regular use of aspirin has been linked to a lower risk of gastrointestinal and other cancers, though evidence for an association with brain tumors is mixed. We examined the association of aspirin and other analgesics with the risk of glioma and meningioma in a large US case–control study. Cases were persons recently diagnosed with glioma or meningioma and treated at medical centers in the southeastern US. Controls were persons sampled from the same communities as the cases combined with friends and other associates of the cases. Information on past use of analgesics (aspirin, other anti-inflammatory agents, and acetaminophen) was collected in structured interviews. Logistic regression was used to estimate odds ratios (ORs) and 95 % confidence intervals (CIs) for analgesic use adjusted for potential confounders. All associations were considered according to indication for use. A total of 1123 glioma cases, 310 meningioma cases and 1296 controls were included in the analysis. For indications other than headache, glioma cases were less likely than controls to report regular use of aspirin (OR 0.69; CI 0.56, 0.87), in a dose-dependent manner (P trend < 0.001). No significant associations were observed with other analgesics for glioma, or any class of pain reliever for meningioma. Results suggest that regular aspirin use may reduce incidence of glioma.
Background--Coronary microvascular dysfunction may contribute to myocardial ischemia during mental stress (MS). However, the role of coronary epicardial and microvascular function in regulating coronary blood flow (CBF) responses during MS remains understudied. We hypothesized that coronary vasomotion during MS is dependent on the coronary microvascular endothelial function and will be reflected in the peripheral microvascular circulation. Methods and Results--In 38 patients aged 59±8 years undergoing coronary angiography, endothelium-dependent and endothelium-independent coronary epicardial and microvascular responses were measured using intracoronary acetylcholine and nitroprusside, respectively, and after MS induced by mental arithmetic testing. Peripheral microvascular tone during MS was measured using peripheral arterial tonometry (Itamar Inc, Caesarea, Israel) as the ratio of digital pulse wave amplitude compared to rest (peripheral arterial tonometry ratio). MS increased the rate-pressure product by 22% (±23%) and constricted epicardial coronary arteries by -5.9% (-10.5%, -2.6%) (median [interquartile range]), P=0.001, without changing CBF. Acetylcholine increased CBF by 38.5% (8.1%, 91.3%), P=0.001, without epicardial coronary diameter change (0.1% [-10.9%, 8.2%], P=not significant). The MS-induced CBF response correlated with endothelium-dependent CBF changes with acetylcholine (r=0.38, P=0.03) but not with the response to nitroprusside. The peripheral arterial tonometry ratio also correlated with the demandadjusted change in CBF during MS (r=-0.60, P=0.004), indicating similarity between the microcirculatory responses to MS in the coronary and peripheral microcirculation. Conclusions--The coronary microvascular response to MS is determined by endothelium-dependent, but not endotheliumindependent, coronary microvascular function. Moreover, the coronary microvascular responses to MS are reflected in the peripheral microvascular circulation.
Objective-Actin cytoskeleton assembly and organization, as a result of focal adhesion (FA) formation during cell adhesion, are dependent on reactive oxygen species and the cellular redox environment. Poldip2 (polymerase δ-interacting protein 2), a novel regulator of NOX4 (NADPH oxidase 4), plays a significant role in reactive oxygen species production and cytoskeletal remodeling. Thus, we hypothesized that endogenous reactive oxygen species derived from Poldip2/NOX4 contribute to redox regulation of actin and cytoskeleton assembly during integrin-mediated cell adhesion. Approach and Results-Using vascular smooth muscle cells, we verified that hydrogen peroxide (H2O2) levels increase during integrin-mediated cell attachment as a result of activation of NOX4. Filamentous actin (F-actin) was oxidized by sulfenylation during cell attachment, with a peak at 3 hours (0.80±0.04 versus 0.08±0.13 arbitrary units at time zero), which was enhanced by overexpression of Poldip2. Depletion of Poldip2 or NOX4 using siRNA, or scavenging of endogenous H2O2 with catalase, inhibited F-actin oxidation by 78±26%, 99±1%, and 98±1%, respectively. To determine the consequence of F-actin oxidation, we examined the binding of F-actin to vinculin, a protein involved in FA complexes that regulates FA maturation. Vinculin binding during cell adhesion as well as migration capacity were inhibited after transfection with actin containing 2 oxidation-resistant point mutations (C272A and C374A). Silencing of Poldip2 or NOX4 also impaired actin-vinculin interaction, which disturbed maturation of FAs and inhibited cell migration. Conclusions-These results suggest that integrin engagement during cell attachment activates Poldip2/Nox4 to oxidize actin, which modulates FA assembly.
Background: Strong evidence supports positive correlation of physical activity with health benefits. Current recommendations by the American Heart Association are a minimum 30 minutes of moderate physical activity 5 days per week. This goal has been equilibrated with 10,000 steps per day.
Hypothesis: Work-related physical activity of cardiovascular (CV) specialists does not meet the currently recommended daily physical activity.
Methods: Eight cardiothoracic (CT) surgeons, 7 general cardiologists, 5 procedural cardiologists, and 8 cardiac anesthesiologists (N = 28) participated in the study. Demographic information on each participant was recorded including age, resting heart rate, body mass index, and medical and social history. Subjects were asked to wear a spring-levered pedometer on their hip for 2 weeks while at work and to record the total number of steps as well as number of hours worked each day.
Results: The average daily steps walked during work were 6540, 6039, 5910, and 5553 for general cardiologists, CT surgeons, procedural cardiologists, and cardiac anesthesiologists, respectively. There were no statistically significant differences in the average number of steps taken per day among the groups. CT surgeons worked 12.4 hours per day compared to 9.3 hours by the cardiac anesthesiologists (P = 0.03).
Conclusions: In this small, single-center study, work-related physical activity of CV specialists did not meet the recommended guidelines. Obtaining the recommended activity level might be a challenge, given their busy work schedule. Therefore, CV specialists must engage in additional, out-of-hours exercise to achieve the recommended daily exercise.