Statin-Induced Rhabdomyolysis Associated With Transjugular Intrahepatic Portosystemic Shunt Placement.

Rhabdomyolysis is a known rare and potentially lethal complication of statin use. This toxic effect is potentiated by alterations in hepatic physiology in patients with cirrhosis. Transjugular intrahepatic portosystemic shunt placement has the potential to further compound this effect; yet, examples of this have not previously been described in the literature. We present a case of a patient who experienced statin-induced rhabdomyolysis likely as a direct consequence of transjugular intrahepatic portosystemic shunt placement.

Ergonomics in IR.

Ergonomic research in the field of interventional radiology remains limited. Existing literature suggests that operators are at increased risk for work-related musculoskeletal disorders related to the use of lead garments and incomplete knowledge of ergonomic principles. Data from existing surgical literature suggest that musculoskeletal disorders may contribute to physician burnout and female operators are at a higher risk of developing musculoskeletal disorders. This review article aims to summarize the existing ergonomic challenges faced by interventional radiologists, reiterate existing solutions to these challenges, and highlight the need for further ergonomic research in multiple areas, including burnout and gender.

Anatomic and Technical Considerations: Inferior Vena Cava Filter Placement.

Inferior vena cava (IVC) filters play an important role in preventing pulmonary embolism in patients with deep venous thrombosis. When preparing for IVC filter placement, there are several important anatomic and technical considerations. The IVC has complex embryologic origins, and normal variants are relatively common which may necessitate a change in technique or approach. When performing the procedure, the choice in imaging modality for deployment, location of deployment, and route of access must be considered. The pediatric and pregnant populations present unique situations that require special consideration and close examination of indications and contraindications.

In vitro and in vivo preclinical profile of abediterol (LAS100977), an inhaled long-acting ß2-adrenoceptor agonist, compared with indacaterol, olodaterol and vilanterol.

Abediterol is a novel long-acting ß2-adrenoceptor agonist (LABA) currently in development for once-daily combination maintenance therapy of asthma and COPD. This study investigated the preclinical profile of abediterol in terms of affinity, potency, selectivity, duration of action and cardiac effects in comparison to the marketed once-daily LABAs indacaterol, olodaterol and vilanterol. Abediterol was the compound with the highest in vitro potency for dog, guinea pig and human ß2-adrenoceptors. In electrical field stimulated guinea pig trachea, abediterol demonstrated 5-, 44- and 77-fold greater potency than olodaterol, indacaterol and vilanterol, respectively. In anaesthetised guinea pigs, inhaled abediterol was also the most potent compound, with 5-20 times higher bronchoprotective potency than other once-daily LABAs against acetylcholine. The bronchoprotective half-life of abediterol in guinea pigs was 36h compared with 51h for indacaterol, 47h for olodaterol, and 18h for vilanterol. In anaesthetised dogs, abediterol also inhibited acetylcholine-induced bronchoconstriction, with higher potency than olodaterol and vilanterol [ID40 (dose inhibiting bronchoconstriction by 40%) of 0.059µg/kg, 0.180µg/kg and 2.870µg/kg, respectively]. In parallel, effects on heart rate in dogs were also measured. Abediterol showed greater safety index (defined as the ratio of the maximal dose without effect on heart rate and the ID40) than olodaterol and vilanterol (10.5 versus 4.9 and 2.4, respectively). Taken together, these data suggest that abediterol offers potent bronchodilation and a sustained duration of action suited to once-daily dosing, plus a reduced potential for class-related cardiac side effects.

Comparative analysis of state-level concussion legislation and review of current practices in concussion.

OBJECT: Forty-two states and the District of Columbia have passed legislation based on the Lystedt law of Washington state, enacted in 2009 to protect young athletes who have sustained a concussion. The aim of this study was to note the several similarities and differences among the various laws. METHODS: Concussion legislation was compared for 50 states and the District of Columbia. Evaluation parameters of this study included stipulations of concussion education, criteria for removal from play, requirements for evaluation and return to play after concussion, and individuals required to assess young athletes. Other parameters that were not consistent across states were also noted. RESULTS: Forty-three states and the District of Columbia have passed concussion legislation, and an additional 4 states have pending legislation. All states with existing legislation support concussion education for coaches; however, only 48% require coaches to undergo formal education. Athletes must be educated on concussion in 86% of states and parents in 88.7%. Suspicion of concussion is a criterion for removal from play in 75% of states; signs and symptoms of concussion are criteria for removal from play in 16% of states. The individuals allowed to evaluate and clear an athlete for return to play differ greatly among states. CONCLUSIONS: Injury prevention legislation holds historical precedent, and given the increasing attention to long-term sequelae of repeated head trauma and concussion, concussion legislation has been rapidly passed in 43 states and the District of Columbia. Although the exact stipulations of these laws vary among states, the overall theme is to increase recognition of concussion in young athletes and ensure that they are appropriately cleared for return to play after concussion.

Strategies for asymptomatic carotid artery stenosis.

The treatment of asymptomatic carotid artery stenosis (ACAS) has continued to evolve for the past 3 decades. With rapidly advancing technology, the results of old trials have become obsolete. While there has been little change in the efficacy of carotid endarterectomy, there have been vast improvements in both medical management and carotid angioplasty with stenting. Finding the best therapy for a given patient can therefore be difficult. In this article, the authors review the current literature regarding treatment options for ACAS and the methods available for stratifying patients who would benefit from surgical versus medical treatment.

Biphenyl/diphenyl ether renin inhibitors: filling the S1 pocket of renin via the S3 pocket.

Structure-based design led to the discovery of a novel class of renin inhibitors in which an unprecedented phenyl ring filling the S1 site is attached to the phenyl ring filling the S3 pocket. Optimization for several parameters including potency in the presence of human plasma, selectivity against CYP3A4 inhibition and improved rat oral bioavailability led to the identification of 8d which demonstrated antihypertensive efficacy in a transgenic rat model of human hypertension.

Discovery of VTP-27999, an Alkyl Amine Renin Inhibitor with Potential for Clinical Utility.

Structure guided optimization of a series of nonpeptidic alkyl amine renin inhibitors allowed the rational incorporation of additional polar functionality. Replacement of the cyclohexylmethyl group occupying the S1 pocket with a (R)-(tetrahydropyran-3-yl)methyl group and utilization of a different attachment point led to the identification of clinical candidate 9. This compound demonstrated excellent selectivity over related and unrelated off-targets, >15% oral bioavailability in three species, oral efficacy in a double transgenic rat model of hypertension, and good exposure in humans.

Optimization of orally bioavailable alkyl amine renin inhibitors.

Structure-guided drug design led to new alkylamine renin inhibitors with improved in vitro and in vivo potency. Lead compound 21a, has an IC(50) of 0.83nM for the inhibition of human renin in plasma (PRA). Oral administration of 21a at 10mg/kg resulted in >20h reduction of blood pressure in a double transgenic rat model of hypertension.

Potent, selective and orally bioavailable dihydropyrimidine inhibitors of Rho kinase (ROCK1) as potential therapeutic agents for cardiovascular diseases.

Recent studies using known Rho-associated kinase isoform 1 (ROCK1) inhibitors along with cellular and molecular biology data have revealed a pivotal role of this enzyme in many aspects of cardiovascular function. Here we report a series of ROCK1 inhibitors which were originally derived from a dihydropyrimidinone core 1. Our efforts focused on the optimization of dihydropyrimidine 2, which resulted in the identification of a series of dihydropyrimidines with improved pharmacokinetics and P450 properties.

PPARdelta activation normalizes cardiac substrate metabolism and reduces right ventricular hypertrophy in congestive heart failure.

Previously, it was shown that selective deletion of peroxisome proliferator activated receptor delta (PPARdelta) in the heart resulted in a cardiac lipotoxicity, hypertrophy, and heart failure. The aim of the present study was to determine the effects of chronic and selective pharmacological activation of PPARdelta in a model of congestive heart failure. PPARdelta-specific agonist treatment (GW610742X at 30 and 100 mg/kg/day for 6-9 weeks) was initiated immediately postmyocardial infarction (MI) in Sprague-Dawley rats. Magnetic resonance imaging/spectroscopy was used to assess cardiac function and energetics. A 1-(13)C glucose clamp was performed to assess relative cardiac carbohydrate versus fat oxidation. Additionally, cardiac hemodynamics and reverse-transcription polymerase chain reaction gene expression analysis was performed. MI rats had significantly reduced left ventricle (LV) ejection fractions and whole heart phosphocreatine/adenosine triphosphate ratio compared with Sham animals (reduction of 43% and 14%, respectively). However, GW610742X treatment had no effect on either parameter. In contrast, the decrease in relative fat oxidation rate observed in both LV and right ventricle (RV) following MI (decrease of 58% and 54%, respectively) was normalized in a dose-dependent manner following treatment with GW610742X. These metabolic changes were associated with an increase in lipid transport/metabolism target gene expression (eg, CD36, CPT1, UCP3). Although there was no difference between groups in LV weight or infarct size measured upon necropsy, there was a dramatic reduction in RV hypertrophy and lung congestion (decrease of 22-48%, P<0.01) with treatment which was associated with a >7-fold decrease (P<0.05) in aterial natriuretic peptide gene expression in RV. Diuretic effects were not observed with GW610742X. In conclusion, chronic treatment with a selective PPARdelta agonist normalizes cardiac substrate metabolism and reduces RV hypertrophy and pulmonary congestion consistent with improvement in congestive heart failure.

Effects of p38 MAPK Inhibitor on angiotensin II-dependent hypertension, organ damage, and superoxide anion production.

Angiotensin II (Ang II) activates p38 mitogen-activated protein kinase (p38 MAPK) and increases reactive oxygen species (ROS), but the nature of the relationship in vivo is not fully understood. We assess the effect of SB239063AN, a highly selective, orally active, p38 MAPK inhibitor, on Ang II-dependent hypertension, target-organ damage and ROS production. Sprague-Dawley rats and MAPKAP kinase-2 knockout mice were infused with Ang II. Ang II infusion increased the levels of phosphorylated p38 MAPK in the heart and aorta. Production of superoxide anion and expression of NAD(P)H oxidase subunit gp91 in the aorta were increased 4- and 5-fold, respectively. In addition, Ang II infusion led to endothelial dysfunction, progressive and sustained hypertension, and cardiac hypertrophy. Treatment with SB239063AN (800 ppm in the diet) significantly attenuated the levels of phosphorylated p38 MAPK in the heart and aorta, reduced superoxide anion generation by 57% (P < 0.01), markedly suppressed gp91 mRNA expression, prevented endothelial dysfunction, and blunted both the hypertension and cardiac hypertrophy. Ang II-dependent hypertension was also significantly attenuated in MAPKAP kinase-2 knockout mice. The results suggest that Ang II induced hypertension, organ damage, and ROS production are possibly mediated by p38 MAPK and inhibition of p38 MAPK may offer a therapeutic approach for cardiovascular disease.

Discovery of aminofurazan-azabenzimidazoles as inhibitors of Rho-kinase with high kinase selectivity and antihypertensive activity.

The discovery, proposed binding mode, and optimization of a novel class of Rho-kinase inhibitors are presented. Appropriate substitution on the 6-position of the azabenzimidazole core provided subnanomolar enzyme potency in vitro while dramatically improving selectivity over a panel of other kinases. Pharmacokinetic data was obtained for the most potent and selective examples and one (6n) has been shown to lower blood pressure in a rat model of hypertension.

Development of dihydropyridone indazole amides as selective Rho-kinase inhibitors.

Rho kinase (ROCK1) mediates vascular smooth muscle contraction and is a potential target for the treatment of hypertension and related disorders. Indazole amide 3 was identified as a potent and selective ROCK1 inhibitor but possessed poor oral bioavailability. Optimization of this lead resulted in the discovery of a series of dihydropyridones, exemplified by 13, with improved pharmacokinetic parameters relative to the initial lead. Indazole substitution played a critical role in decreasing clearance and improving oral bioavailability.

The peptidic urotensin-II receptor ligand GSK248451 possesses less intrinsic activity than the low-efficacy partial agonists SB-710411 and urantide in native mammalian tissues and recombinant cell systems.

Several peptidic urotensin-II (UT) receptor antagonists exert 'paradoxical' agonist activity in recombinant cell- and tissue-based bioassay systems, likely the result of differential urotensin-II receptor (UT receptor) signal transduction/coupling efficiency between assays. The present study has examined this phenomenon in mammalian arteries and recombinant UT-HEK (human embryonic kidney) cells.BacMam-mediated recombinant UT receptor upregulation in HEK cells augmented agonist activity for all four peptidic UT ligands studied. The nominal rank order of relative intrinsic efficacy was U-II>urantide ([Pen(5)-DTrp(7)-Orn(8)]hU-II(4-11))>SB-710411 (Cpa-c[DCys-Pal-DTrp-Lys-Val-Cys]-Cpa-amide)>>GSK248451 (Cin-c[DCys-Pal-DTrp-Orn-Val-Cys]-His-amide) (the relative coupling efficiency of recombinant HEK cells was cat>human>>rat UT receptor). The present study further demonstrated that the use of high signal transduction/coupling efficiency isolated blood vessel assays (primate>cat arteries) is required in order to characterize UT receptor antagonism thoroughly. This cannot be attained simply by using the rat isolated aorta, an artery with low signal transduction/coupling efficiency in which low-efficacy agonists appear to function as antagonists. In contrast to the 'low-efficacy agonists' urantide and SB-710411, GSK248451 functioned as a potent UT receptor antagonist in all native isolated tissues studied (UT receptor selectivity was confirmed in the rat aorta). Further, GSK248451 exhibited an extremely low level of relative intrinsic activity in recombinant HEK cells (4-5-fold less than seen with urantide). Since GSK248451 (1 mg kg(-1), i.v.) blocked the systemic pressor actions of exogenous U-II in the anaesthetized cat, it represents a suitable peptidic tool antagonist for delineating the role of U-II in the aetiology of mammalian cardiometabolic diseases.

Phosphorylation of BLM, dissociation from topoisomerase IIIalpha, and colocalization with gamma-H2AX after topoisomerase I-induced replication damage.

Topoisomerase I-associated DNA single-strand breaks selectively trapped by camptothecins are lethal after being converted to double-strand breaks by replication fork collisions. BLM (Bloom's syndrome protein), a RecQ DNA helicase, and topoisomerase IIIalpha (Top3alpha) appear essential for the resolution of stalled replication forks (Holliday junctions). We investigated the involvement of BLM in the signaling response to Top1-mediated replication DNA damage. In BLM-complemented cells, BLM colocalized with promyelocytic leukemia protein (PML) nuclear bodies and Top3alpha. Fibroblasts without BLM showed an increased sensitivity to camptothecin, enhanced formation of Top1-DNA complexes, and delayed histone H2AX phosphorylation (gamma-H2AX). Camptothecin also induced nuclear relocalization of BLM, Top3alpha, and PML protein and replication-dependent phosphorylation of BLM on threonine 99 (T99p-BLM). T99p-BLM was also observed following replication stress induced by hydroxyurea. Ataxia telangiectasia mutated (ATM) protein and AT- and Rad9-related protein kinases, but not DNA-dependent protein kinase, appeared to play a redundant role in phosphorylating BLM. Following camptothecin treatment, T99p-BLM colocalized with gamma-H2AX but not with Top3alpha or PML. Thus, BLM appears to dissociate from Top3alpha and PML following its phosphorylation and facilitates H2AX phosphorylation in response to replication double-strand breaks induced by Top1. A defect in gamma-H2AX signaling in response to unrepaired replication-mediated double-strand breaks might, at least in part, explain the camptothecin-sensitivity of BLM-deficient cells.

Synthetic LXR agonists increase LDL in CETP species.

Liver X receptor (LXR) nuclear receptors regulate the expression of genes involved in whole body cholesterol trafficking, including absorption, excretion, catabolism, and cellular efflux, and possess both anti-inflammatory and antidiabetic actions. Accordingly, LXR is considered an appealing drug target for multiple indications. Synthetic LXR agonists demonstrated inhibition of atherosclerosis progression in murine genetic models; however, these and other studies indicated that their major undesired side effect is an increase of plasma and hepatic triglycerides. A significant impediment to extrapolating results with LXR agonists from mouse to humans is the absence in mice of cholesteryl ester transfer protein, a known LXR target gene, and the upregulation in mice but not humans of cholesterol 7alpha-hydroxylase. To better predict the human response to LXR agonism, two synthetic LXR agonists were examined in hamsters and cynomolgus monkeys. In contrast to previously published results in mice, neither LXR agonist increased HDL-cholesterol in hamsters, and similar results were obtained in cynomolgus monkeys. Importantly, in both species, LXR agonists increased LDL-cholesterol, an unfavorable effect not apparent from earlier murine studies. These results reveal additional problems associated with current synthetic LXR agonists and emphasize the importance of profiling compounds in preclinical species with a more human-like LXR response and lipoprotein metabolism.

Urotensin-II: a novel systemic hypertensive factor in the cat.

Urotensin-II, a potent mammalian vasoconstrictor, may play a role in the etiology of essential hypertension. However, a species suitable for assessing such a role, one where a "classical" systemic hypertensive response (increase in mean blood pressure and systemic vascular resistance) is observed following bolus i.v. urotensin-II administration, has yet to be identified. The present study demonstrates that the cat may represent such a species since urotensin-II potently (pEC(50)s 9.68+/-0.24-8.73+/-0.08) and efficaciously (E(max) 73+/-15%-205+/-21% KCl) constricts all feline isolated arteries studied (aortae, renal, femoral, carotid, and mesenteric conduit/resistance). Accordingly, exogenous urotensin-II (1 nmol/kg, i.v.) effectively doubles both mean blood pressure (from 99+/-14 to 183+/-15 mmHg) and systemic vascular resistance (from 0.36+/-0.12 to 0.86+/-0.20 mmHg/ml/min) in the anaesthetized cat (without altering heart rate or stroke volume). Thus, in view of these profound contractile effects, the cat could be suitable for determining the effects of urotensin-II receptor antagonism on cardiovascular homeostasis in both normal and diseased states.

p38 mitogen-activated protein kinase inhibitors for the treatment of chronic cardiovascular disease.

p38 Mitogen-activated protein kinase (MAPK) has been implicated in cardiovascular disease and is activated by various factors, including neurohormones (e.g., catecholamines, angiotensin II and endothelin), hypoxia and wall stress. Activation of p38 MAPK can cause cardiac hypertrophy, negative inotropy and endothelial dysfunction. All of these conditions lead to chronic cardiovascular disease, which is becoming an ever growing burden on society. p38 MAPK inhibition may therefore be an interesting therapeutic approach to the treatment of various cardiovascular diseases. However, in vitro and in vivo results are conflicting and caution must be applied in the translation of bench results to the clinic.

Deletion of the UT receptor gene results in the selective loss of urotensin-II contractile activity in aortae isolated from UT receptor knockout mice.

1 Urotensin-II (U-II) is among the most potent mammalian vasoconstrictors identified and may play a role in the aetiology of essential hypertension. Currently, only one mouse U-II receptor (UT) gene has been cloned. It is postulated that this protein is solely responsible for mediating U-II-induced vasoconstriction. 2 This hypothesis has been investigated in the present study, which assessed basal haemodynamics and vascular reactivity to hU-II in wild-type (UT((+/+))) and UT receptor knockout (UT((-/-))) mice. 3 Basal left ventricular end-diastolic and end-systolic volumes/pressures, stroke volumes, mean arterial blood pressures, heart rates, cardiac outputs and ejection fractions in UT((+/+)) mice and in UT((-/-)) mice were similar. 4 Relative to UT((+/+)) mouse isolated thoracic aorta, where hU-II was a potent spasmogen (pEC(50)=8.26+/-0.08) that evoked relatively little vasoconstriction (17+/-2% 60 mM KCl), vessels isolated from UT((-/-)) mice did not respond to hU-II. However, in contrast, the superior mesenteric artery isolated from both the genotypes did not contract in the presence of hU-II. Reactivity to unrelated vasoconstrictors (phenylephrine, endothelin-1, KCl) and endothelium-dependent/independent vasodilator agents (carbachol, sodium nitroprusside) was similar in the aorta and superior mesenteric arteries isolated from both the genotypes. 5 The present study is the first to directly link hU-II-induced vasoconstriction with the UT receptor. Deletion of the UT receptor gene results in loss of hU-II contractile action with no 'nonspecific' alterations in vascular reactivity. However, as might be predicted based on the limited contractile efficacy recorded in vitro, the contribution that hU-II and its receptor make to basal systemic haemodynamics appears to be negligible in this species.