Risk factors for lack of statin therapy in patients with diabetes and coronary artery disease

BACKGROUND

Patients with both diabetes and coronary artery disease (CAD) have exceedingly high cardiovascular risk. Nevertheless, little is known about prevalence of statin therapy in this population and reasons why some patients may not be receiving this potentially life-saving treatment.

OBJECTIVE

To investigate prevalence and predictors of statin therapy in patients with combined diabetes and CAD.

METHODS

We conducted a retrospective cohort study of primary care patients with diabetes and CAD followed at 2 academic medical centers between 2000 and 2011. We used multivariable logistic regression to identify patient and provider characteristics associated with (1) statin initiation (any history of statin therapy) and (2) statin persistence (active statin prescription at the study end).

RESULTS

Of 8488 study patients, 7427 (87.5%) ever received statins and 6212 (73.2%) had persistent statin therapy. Younger age (odds ratio [OR], 1.26 per decade), smoking (OR, 1.49) and cardiologist evaluation (OR, 2.26) were associated with statin initiation (P < .0001 for all). Younger age (OR, 1.17), family history of CAD (OR, 1.39), no adverse reactions to statins (OR, 1.40; P < .0001 for all), female sex (OR, 1.22; P = .005), history of smoking (OR, 1.22; P = .003), cardiologist evaluation (OR, 1.23; P = .002), and lower HbA1c (OR, 1.04; P = 0.003) were associated with persistent statin therapy. Only 362 (29.8%) of the 1215 patients without persistent statin therapy had tried at least 2 statins, and 58 (4.8%) tried 3 statins.

CONCLUSIONS

Many patients with combined CAD and diabetes are not treated with statins, although in this very high-risk group, even moderate-intensity statins result in meaningful reductions in cardiovascular events. Higher cardiovascular risk and cardiologist evaluation were associated with higher prevalence of statin therapy.

Inhibition of BET bromodomain attenuates angiotensin II induced abdominal aortic aneurysm in ApoE-/- mice

BACKGROUND

Excessive degradation of extracellular matrix by matrix metalloproteinases (MMP) is the major pathological feature of abdominal aortic aneurysm (AAA). Suppression of extracellular matrix degradation attenuates AAA initiation and progression in preclinical models. In the present study, we wanted to test the effect of JQ1, a small chemical molecule that selectively targets bromodomain and extra-terminal domain (BET), on AngII induced AAA formation in ApoE^-/- mice.

METHODS AND RESULTS

To study the role of BET bromodomain in AAA pathogenesis, male ApoE^-/- mice were infused with angiotensin II (AngII, 1000ng/kg/min) for 21days and cotreated with JQ1 (50mg/kg daily) or vehicle control (DMSO). In the in vitro study, we determined the mRNA expression of MMP genes by qPCR and their activity both by the kit and gelatin zymography assay. BET bromodomain inhibition resulted in decreased abdominal aortic diameter (P<0.05) measured by in vivo vascular ultrasound and ex vivo pathologic assessment of aortas. In pursuit of mechanisms for this effect on AAA, we observed that JQ1 treatment led to a downregulation of metalloproteinase gene expression and enzymatic activity both in vitro and in vivo.

CONCLUSIONS

BET bromodomain inhibition improved AAA pathological sequelae, and this effect might be achieved though suppression of MMP genes expression and their activity.

Extensive metabolic disorders are present in APC(min) tumorigenesis mice

Wnt signaling plays essential role in mesenchymal stem cell (MSC) differentiation. Activation of Wnt signaling suppresses adipogenesis, but promotes osteogenesis in MSC. Adenomatous polyposis coli (APC) is a negative regulator of β-catenin and Wnt signaling activity. The mutation of APC gene leads to the activation of Wnt signaling and is responsible for tumorigenesis in APC(min) mouse; however, very few studies focused on its metabolic abnormalities. The present study reports a widespread metabolic disorder phenotype in APC(min) mice. The old APC(min) mice have decreased body weight and impaired adipogenesis, but severe hyperlipidemia, which mimic the phenotypes of Familial Adenomatous Polyposis (FAP), an inherited disease also caused by APC gene mutation in human. We found that the expression of lipid metabolism and free fat acids (FA) use genes in the white adipose tissue (WAT) of the APC(min) mice is much lower than those of control. The changed gene expression pattern may lead to the disability of circulatory lipid transportation and storage at WAT. Moreover, the APC(min) mice could not maintain the core body temperature in cold condition. PET-CT determination revealed that the BAT of APC(min) mice has significantly impaired ability to take up (18)FDG from the blood. Morphological studies identified that the brown adipocytes of APC(min) mice were filled with lipid droplets but fewer mitochondria. These results matched with the findings of impaired BAT function in APC(min) mice. Collectively, our study explores a new mechanism that explains abnormal metabolism in APC(min) mice and provides insights into studying the metabolic disorders of FAP patients.

Drivers of the Sex Disparity in Statin Therapy in Patients with Coronary Artery Disease: A Cohort Study

BACKGROUND

Women are less likely to be prescribed statins than men. Existing reports explain only a fraction of this difference. We conducted a study to identify factors that account for sex differences in statin therapy among patients with coronary artery disease (CAD).

METHODS AND RESULTS

We retrospectively studied 24,338 patients with CAD who were followed for at least a year between 2000 and 2011 at two academic medical centers. Women (9,006 / 37% of study patients) were less likely to either have initiated statin therapy (81.9% women vs. 87.7% men) or to have persistent statin therapy at the end of follow-up (67.0% women vs. 71.4% men). Women were older (72.9 vs. 68.4 years), less likely to have ever smoked (49.8% vs. 65.6%), less likely to have been evaluated by a cardiologist (57.5% vs. 64.5%) and more likely to have reported an adverse reaction to a statin (27.1% vs. 21.7%) (p < 0.0001 for all). In multivariable analysis, patients with history of smoking (OR 1.094; p 0.017), younger age (OR 1.013 / year), cardiologist evaluation (OR 1.337) and no reported adverse reactions to statins (OR 1.410) were more likely (p < 0.0001 for all) to have persistent statin therapy. Together, these four factors accounted for 90.4% of the sex disparity in persistent statin therapy.

CONCLUSIONS

Several specific factors appear to underlie divergent statin therapy in women vs. men. Identifying such drivers may facilitate programmatic interventions and stimulate further research to overcome sex differences in applying proven interventions for cardiovascular risk reduction.

Brown Fat and Browning for the Treatment of Obesity and Related Metabolic Disorders

Brown fat is a specialized fat depot that can increase energy expenditure and produce heat. After the recent discovery of the presence of active brown fat in human adults and novel transcription factors controlling brown adipocyte differentiation, the field of the study of brown fat has gained great interest and is rapidly growing. Brown fat expansion and/or activation results in increased energy expenditure and a negative energy balance in mice and limits weight gain. Brown fat is also able to utilize blood glucose and lipid and results in improved glucose metabolism and blood lipid independent of weight loss. Prolonged cold exposure and beta adrenergic agonists can induce browning of white adipose tissue. The inducible brown adipocyte, beige adipocyte evolving by thermogenic activation of white adipose tissue have different origin and molecular signature from classical brown adipocytes but share the characteristics of high mitochondria content, UCP1 expression and thermogenic capacity when activated. Increasing browning may also be an efficient way to increase whole brown fat activity. Recent human studies have shown possibilities that findings in mice can be reproduced in human, making brown fat a good candidate organ to treat obesity and its related disorders.

Differential role of an NF-κB transcriptional response element in endothelial versus intimal cell VCAM-1 expression

RATIONALE

Human and murine Vcam1 promoters contain 2 adjacent nuclear factor-κB (NF-κB)-binding elements. Both are essential for cytokine-induced transcription of transiently transfected promoter-reporter constructs. However, the relevance of these insights to regulation of the endogenous Vcam1 gene and to pathophysiological processes in vivo remained unknown.

OBJECTIVE

Determine the role of the 5' NF-κB-binding element in expression of the endogenous Vcam1 gene.

METHODS AND RESULTS

Homologous recombination in embryonic stem cells was used to inactivate the 5' NF-κB element in the Vcam1 promoter and alter 3 nucleotides in the 5' untranslated region to allow direct comparison of wild-type versus mutant allele RNA expression and chromatin configuration in heterozygous mice. Systemic treatment with inflammatory cytokines or endotoxin (lipopolysaccharide) induced lower expression of the mutant allele relative to wild-type by endothelial cells in the aorta, heart, and lungs. The mutant allele also showed lower endothelial expression in 2-week atherosclerotic lesions in Vcam1 heterozygous/low-density lipoprotein receptor-deficient mice fed a cholesterol-rich diet. In vivo chromatin immunoprecipitation assays of heart showed diminished lipopolysaccharide-induced association of RNA polymerase 2 and NF-κB p65 with the mutant promoter. In contrast, expression of mutant and wild-type alleles was comparable in intimal cells of wire-injured carotid artery and 4- to 12-week atherosclerotic lesions.

CONCLUSIONS

This study highlights differences between in vivo and in vitro promoter analyses, and reveals a differential role for a NF-κB transcriptional response element in endothelial vascular cell adhesion molecule-1 expression induced by inflammatory cytokines or a cholesterol-rich diet versus intimal cell expression in atherosclerotic lesions and injured arteries.

Effects of statin therapy on coronary artery plaque volume and high-risk plaque morphology in HIV-infected patients with subclinical atherosclerosis: a randomised, double-blind, placebo-controlled trial

BACKGROUND

HIV-infected patients have a high risk of myocardial infarction. We aimed to assess the ability of statin treatment to reduce arterial inflammation and achieve regression of coronary atherosclerosis in this population.

METHODS

In a randomised, double-blind, placebo-controlled trial, 40 HIV-infected participants with subclinical coronary atherosclerosis, evidence of arterial inflammation in the aorta by fluorodeoxyglucose (FDG)-PET, and LDL-cholesterol concentration of less than 3.37 mmol/L (130 mg/dL) were randomly assigned (1:1) to 1 year of treatment with atorvastatin or placebo. Randomisation was by the Massachusetts General Hospital (MGH) Clinical Research Pharmacy with a permuted-block algorithm, stratified by sex with a fixed block size of four. Study codes were available only to the MGH Research Pharmacy and not to study investigators or participants. The prespecified primary endpoint was arterial inflammation as assessed by FDG-PET of the aorta. Additional prespecified endpoints were non-calcified and calcified plaque measures and high risk plaque features assessed with coronary CT angiography and biochemical measures. Analysis was done by intention to treat with all available data and without imputation for missing data. The trial is registered with ClinicalTrials.gov, number NCT00965185.

FINDINGS

The study was done from Nov 13, 2009, to Jan 13, 2014. 19 patients were assigned to atorvastatin and 21 to placebo. 37 (93%) of 40 participants completed the study, with equivalent discontinuation rates in both groups. Baseline characteristics were similar between groups. After 12 months, change in FDG-PET uptake of the most diseased segment of the aorta was not different between atorvastatin and placebo, but technically adequate results comparing longitudinal changes in identical regions could be assessed in only 21 patients (atorvastatin Δ -0.03, 95% CI -0.17 to 0.12, vs placebo Δ -0.06, -0.25 to 0.13; p=0.77). Change in plaque could be assessed in all 37 people completing the study. Atorvastatin reduced non-calcified coronary plaque volume relative to placebo: median change -19.4% (IQR -39.2 to 9.3) versus 20.4% (-7.1 to 94.4; p=0.009, n=37). The number of high-risk plaques was significantly reduced in the atorvastatin group compared with the placebo group: change in number of low attenuation plaques -0.2 (95% CI -0.6 to 0.2) versus 0.4 (0.0, 0.7; p=0.03; n=37); and change in number of positively remodelled plaques -0.2 (-0.4 to 0.1) versus 0.4 (-0.1 to 0.8; p=0.04; n=37). Direct LDL-cholesterol (-1.00 mmol/L, 95% CI -1.38 to 0.61 vs 0.30 mmol/L, 0.04 to 0.55, p<0.0001) and lipoprotein-associated phospholipase A2 (-52.2 ng/mL, 95% CI -70.4 to -34.0, vs -13.3 ng/mL, -32.8 to 6.2; p=0.005; n=37) decreased significantly with atorvastatin relative to placebo. Statin therapy was well tolerated, with a low incidence of clinical adverse events.

INTERPRETATION

No significant effects of statin therapy on arterial inflammation of the aorta were seen as measured by FDG-PET. However, statin therapy reduced non-calcified plaque volume and high-risk coronary plaque features in HIV-infected patients. Further studies should assess whether reduction in high-risk coronary artery disease translates into effective prevention of cardiovascular events in this at-risk population.

FUNDING

National Institutes of Health, Harvard Clinical and Translational Science Center, National Center for Research Resources.

Retinaldehyde dehydrogenase 1 deficiency inhibits PPARγ-mediated bone loss and marrow adiposity

PPARγ, a ligand-activated nuclear receptor, regulates fundamental aspects of bone homeostasis and skeletal remodeling. PPARγ-activating anti-diabetic thiazolidinediones in clinical use promote marrow adiposity, bone loss, and skeletal fractures. As such, delineating novel regulatory pathways that modulate the action of PPARγ, and its obligate heterodimeric partner RXR, may have important implications for our understanding and treatment of disorders of low bone mineral density. We present data here establishing retinaldehyde dehydrogenase 1 (Aldh1a1) and its substrate retinaldehyde (Rald) as novel determinants of PPARγ-RXR actions in the skeleton. When compared to wild type (WT) controls, retinaldehyde dehydrogenase-deficient (Aldh1a1(-/-)) mice were protected against bone loss and marrow adiposity induced by either the thiazolidinedione rosiglitazone or a high fat diet, both of which potently activate the PPARγ-RXR complex. Consistent with these results, Rald, which accumulates in vivo in Aldh1a1(-/-) mice, protects against rosiglitazone-mediated inhibition of osteoblastogenesis in vitro. In addition, Rald potently inhibits in vitro adipogenesis and osteoclastogenesis in WT mesenchymal stem cells (MSCs) and hematopoietic stem cells (HSCs) respectively. Primary Aldh1a1(-/-) HSCs also demonstrate impaired osteoclastogenesis in vitro compared to WT controls. Collectively, these findings identify Rald and retinoid metabolism through Aldh1a1 as important novel modulators of PPARγ-RXR transactivation in the marrow niche.

NF-κB directs dynamic super enhancer formation in inflammation and atherogenesis

Proinflammatory stimuli elicit rapid transcriptional responses via transduced signals to master regulatory transcription factors. To explore the role of chromatin-dependent signal transduction in the atherogenic inflammatory response, we characterized the dynamics, structure, and function of regulatory elements in the activated endothelial cell epigenome. Stimulation with tumor necrosis factor alpha prompted a dramatic and rapid global redistribution of chromatin activators to massive de novo clustered enhancer domains. Inflammatory super enhancers formed by nuclear factor-kappa B accumulate at the expense of immediately decommissioned, basal endothelial super enhancers, despite persistent histone hyperacetylation. Mass action of enhancer factor redistribution causes momentous swings in transcriptional initiation and elongation. A chemical genetic approach reveals a requirement for BET bromodomains in communicating enhancer remodeling to RNA Polymerase II and orchestrating the transition to the inflammatory cell state, demonstrated in activated endothelium and macrophages. BET bromodomain inhibition abrogates super enhancer-mediated inflammatory transcription, atherogenic endothelial responses, and atherosclerosis in vivo.

Diabetes and cardiovascular disease in older adults: current status and future directions

The prevalence of diabetes increases with age, driven in part by an absolute increase in incidence among adults aged 65 years and older. Individuals with diabetes are at higher risk for cardiovascular disease, and age strongly predicts cardiovascular complications. Inflammation and oxidative stress appear to play some role in the mechanisms underlying aging, diabetes, cardiovascular disease, and other complications of diabetes. However, the mechanisms underlying the age-associated increase in risk for diabetes and diabetes-related cardiovascular disease remain poorly understood. Moreover, because of the heterogeneity of the older population, a lack of understanding of the biology of aging, and inadequate study of the effects of treatments on traditional complications and geriatric conditions associated with diabetes, no consensus exists on the optimal interventions for older diabetic adults. The Association of Specialty Professors, along with the National Institute on Aging, the National Institute of Diabetes and Digestive and Kidney Diseases, the National Heart, Lung, and Blood Institute, and the American Diabetes Association, held a workshop, summarized in this Perspective, to discuss current knowledge regarding diabetes and cardiovascular disease in older adults, identify gaps, and propose questions to guide future research.

Reductions in systolic blood pressure with liraglutide in patients with type 2 diabetes: insights from a patient-level pooled analysis of six randomized clinical trials

AIMS

To quantify the effect of liraglutide on systolic blood pressure (SBP) and pulse in patients with type 2 diabetes (T2D), and assess the influence of covariates on observed SBP reductions.

METHODS

A patient-level pooled analysis of six phase 3, randomized trials was conducted.

RESULTS

The analysis included 2792 randomized patients. In the intention-to-treat population (n=2783), mean [±SE] SBP reductions from baseline with liraglutide 1.2 mg (2.7 [0.8] mmHg) and 1.8 mg (2.9 [0.7] mmHg) once daily were significantly greater than with placebo (0.5 [0.9] mmHg; P=0.0029 and P=0.0004, respectively) after 26 weeks, and were evident after 2 weeks. Liraglutide was also associated with significantly greater SBP reductions than glimepiride and, at a dose of 1.8 mg, insulin glargine and rosiglitazone. SBP reductions with liraglutide weakly correlated with weight loss (Pearson's correlation coefficient: 0.08-0.12; P≤0.0148). No dependence of these reductions on concomitant antihypertensive medications was detected (P=0.1304). Liraglutide 1.2 and 1.8 mg were associated with mean increases in pulse of 3 beats per minute (bpm), versus a 1 bpm increase with placebo (P<0.0001 for each dose versus placebo).

CONCLUSIONS

Liraglutide reduces SBP in patients with T2D, including those receiving concomitant antihypertensive medication.

Residual macrovascular risk in 2013: what have we learned?

Cardiovascular disease poses a major challenge for the 21st century, exacerbated by the pandemics of obesity, metabolic syndrome and type 2 diabetes. While best standards of care, including high-dose statins, can ameliorate the risk of vascular complications, patients remain at high risk of cardiovascular events. The Residual Risk Reduction Initiative (R3i) has previously highlighted atherogenic dyslipidaemia, defined as the imbalance between proatherogenic triglyceride-rich apolipoprotein B-containing-lipoproteins and antiatherogenic apolipoprotein A-I-lipoproteins (as in high-density lipoprotein, HDL), as an important modifiable contributor to lipid-related residual cardiovascular risk, especially in insulin-resistant conditions. As part of its mission to improve awareness and clinical management of atherogenic dyslipidaemia, the R3i has identified three key priorities for action: i) to improve recognition of atherogenic dyslipidaemia in patients at high cardiometabolic risk with or without diabetes; ii) to improve implementation and adherence to guideline-based therapies; and iii) to improve therapeutic strategies for managing atherogenic dyslipidaemia. The R3i believes that monitoring of non-HDL cholesterol provides a simple, practical tool for treatment decisions regarding the management of lipid-related residual cardiovascular risk. Addition of a fibrate, niacin (North and South America), omega-3 fatty acids or ezetimibe are all options for combination with a statin to further reduce non-HDL cholesterol, although lacking in hard evidence for cardiovascular outcome benefits. Several emerging treatments may offer promise. These include the next generation peroxisome proliferator-activated receptorα agonists, cholesteryl ester transfer protein inhibitors and monoclonal antibody therapy targeting proprotein convertase subtilisin/kexin type 9. However, long-term outcomes and safety data are clearly needed. In conclusion, the R3i believes that ongoing trials with these novel treatments may help to define the optimal management of atherogenic dyslipidaemia to reduce the clinical and socioeconomic burden of residual cardiovascular risk.

A diurnal serum lipid integrates hepatic lipogenesis and peripheral fatty acid use

Food intake increases the activity of hepatic de novo lipogenesis, which mediates the conversion of glucose to fats for storage or utilization. In mice, this program follows a circadian rhythm that peaks with nocturnal feeding^1,2 and is repressed by Rev-erbα/β and an HDAC3-containing complex^3–5 during the day. The transcriptional activators controlling rhythmic lipid synthesis in the dark cycle remain poorly defined. Disturbances in hepatic lipogenesis are also associated with systemic metabolic phenotypes^6–8, suggesting that lipogenesis in the liver communicates with peripheral tissues to control energy substrate homeostasis. Here we identify a PPARδ-dependent de novo lipogenic pathway in the liver that modulates fat utilization by muscle via a circulating lipid. The nuclear receptor PPARδ controls diurnal expression of lipogenic genes in the dark/feeding cycle. Liver-specific PPARδ activation increases, while hepatocyte-Ppard deletion reduces, muscle fatty acid (FA) uptake. Unbiased metabolite profiling identifies PC(18:0/18:1), or 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC), as a serum lipid regulated by diurnal hepatic PPARδ activity. PC(18:0/18:1) reduces postprandial lipid levels and increases FA utilization through muscle PPARα. High fat feeding diminishes rhythmic production of PC(18:0/18:1), whereas PC(18:0/18:1) administration in db/db mice improves metabolic homeostasis. These findings reveal an integrated regulatory circuit coupling lipid synthesis in the liver to energy utilization in muscle by coordinating the activity of two closely related nuclear receptors. These data implicate alterations in diurnal hepatic PPARδ-PC(18:0/18:1) signaling in metabolic disorders including obesity.

Deficiency of retinaldehyde dehydrogenase 1 induces BMP2 and increases bone mass in vivo

The effects of retinoids, the structural derivatives of vitamin A (retinol), on post-natal peak bone density acquisition and skeletal remodeling are complex and compartment specific. Emerging data indicates that retinoids, such as all trans retinoic acid (ATRA) and its precursor all trans retinaldehyde (Rald), exhibit distinct and divergent transcriptional effects in metabolism. Despite these observations, the role of enzymes that control retinoid metabolism in bone remains undefined. In this study, we examined the skeletal phenotype of mice deficient in retinaldehyde dehydrogenase 1 (Aldh1a1), the enzyme responsible for converting Rald to ATRA in adult animals. Bone densitometry and micro-computed tomography (µCT) demonstrated that Aldh1a1-deficient (Aldh1a1^−/−) female mice had higher trabecular and cortical bone mass compared to age and sex-matched control C57Bl/6 wild type (WT) mice at multiple time points. Histomorphometry confirmed increased cortical bone thickness and demonstrated significantly higher bone marrow adiposity in Aldh1a1^−/− mice. In serum assays, Aldh1a1^−/− mice also had higher serum IGF-1 levels. In vitro, primary Aldh1a1^−/− mesenchymal stem cells (MSCs) expressed significantly higher levels of bone morphogenetic protein 2 (BMP2) and demonstrated enhanced osteoblastogenesis and adipogenesis versus WT MSCs. BMP2 was also expressed at higher levels in the femurs and tibias of Aldh1a1^−/− mice with accompanying induction of BMP2-regulated responses, including expression of Runx2 and alkaline phosphatase, and Smad phosphorylation. In vitro, Rald, which accumulates in Aldh1a1^−/− mice, potently induced BMP2 in WT MSCs in a retinoic acid receptor (RAR)-dependent manner, suggesting that Rald is involved in the BMP2 increases seen in Aldh1a1 deficiency in vivo. Collectively, these data implicate Aldh1a1 as a novel determinant of cortical bone density and marrow adiposity in the skeleton in vivo through modulation of BMP signaling.

BET bromodomains mediate transcriptional pause release in heart failure

Heart failure (HF) is driven by the interplay between regulatory transcription factors and dynamic alterations in chromatin structure. Pathologic gene transactivation in HF is associated with recruitment of histone acetyl-transferases and local chromatin hyperacetylation. We therefore assessed the role of acetyl-lysine reader proteins, or bromodomains, in HF. Using a chemical genetic approach, we establish a central role for BET family bromodomain proteins in gene control during HF pathogenesis. BET inhibition potently suppresses cardiomyocyte hypertrophy in vitro and pathologic cardiac remodeling in vivo. Integrative transcriptional and epigenomic analyses reveal that BET proteins function mechanistically as pause-release factors critical to expression of genes that are central to HF pathogenesis and relevant to the pathobiology of failing human hearts. This study implicates epigenetic readers as essential effectors of transcriptional pause release during HF pathogenesis and identifies BET coactivator proteins as therapeutic targets in the heart.

Endothelial lipase is a critical determinant of high-density lipoprotein-stimulated sphingosine 1-phosphate-dependent signaling in vascular endothelium

OBJECTIVE

In addition to an extensively characterized role of high-density lipoprotein (HDL) in reverse cholesterol transport, bioactive lipids bound to HDL can also exert diverse vascular effects. Despite this, integration of HDL action in the vasculature with pathways that metabolize HDL and release bioactive lipids has been much less explored. The effects of HDL on endothelial cells are mediated in part by HDL-associated sphingosine 1-phosphate (S1P), which binds to S1P1 receptors and promotes activation of endothelial NO synthase (eNOS) and the kinase Akt. In these studies, we characterized the role of endothelial lipase (EL) in the control of endothelial signaling and biology, including those mediated by HDL-associated S1P.

APPROACH AND RESULTS

HDL-induced angiogenesis in aortic rings from EL-deficient (EL(-/-)) mice was markedly decreased compared with wild-type controls. In cultured endothelial cells, small interfering RNA-mediated knockdown of EL abrogated HDL-promoted endothelial cell migration and tube formation. Small interfering RNA-mediated EL knockdown also attenuated HDL-induced phosphorylation of eNOS(1179) and Akt(473). S1P stimulation restored HDL-induced endothelial migration and Akt/eNOS phosphorylation that had been blocked by small interfering RNA-mediated EL knockdown. HDL-induced endothelial cell migration and Akt/eNOS phosphorylation were completely inhibited by the S1P1 antagonist W146 but not by the S1P3 antagonist CAY10444.

CONCLUSIONS

EL is a critical determinant of the effects of HDL on S1P-mediated vascular responses and acts on HDL to promote activation of S1P1, leading to Akt/eNOS phosphorylation and subsequent endothelial migration and angiogenesis. The role of EL in HDL-associated S1P effects provides new insights into EL action, the responses seen through EL and HDL interaction, and S1P signaling.

Abstract 181: BET Bromodomain Inhibition Suppresses Endothelial Inflammation and Atherosclerosis

Introduction

The BET bromodomain-containing family of proteins (BRD2, BRD3, BRD4) are epigenetic readers that coactivate transcription. Recent evidence indicates that BETs promote carcinogenesis and inflammation in sepsis, while BET bromodomain inhibitors are promising anti-cancer therapies. However, the role of chromatin remodeling in atherosclerosis in general and through BETs in particular remains unknown.

Hypothesis

We hypothesized that BET bromodomain-containing proteins coactivate proinflammatory responses in the vasculature with functional effects that promote atherogenesis.

Methods and Results

BET bromodomain inhibition, achieved with the highly selective, small-molecule inhibitor JQ1 significantly reduced early atherosclerosis (12 weeks) in cholesterol-fed, LDL receptor-null mice. In pursuing mechanisms for this effect, we identified BET protein expression in mouse and human endothelial cells (ECs) as well as endothelium from human atherosclerotic plaque. Treating human umbilical vein endothelial cells (HUVECs) with either JQ1 or siRNA to BRD2 or BRD4 potently suppresses TNFα-induced expression of adhesion molecules (SELE, VCAM1) and chemokines (CCL2, CXCL8). In chromatin immunoprecipation studies, TNFα stimulation of ECs recruited BETs to adhesion molecule and chemokine promoters coincident with RNA polymerase II and cyclin T1 localization, without altering NF-κB recruitment. In functional studies, JQ1 suppressed 1) monocyte adhesion to TNFα-activated HUVECs, 2) leukocyte rolling on cremaster post-capillary venules (intravital microscopy); 3) leukocyte transmigration (parallel-plate flow chamber); and 4) monocyte recruitment in thioglycolate-induced peritonitis in vivo .

Conclusions

BET bromodomain-containing proteins are novel determinants of pro-inflammatory transcription in the endothelium. Targeting chromatin by BET bromodomain inhibition may be a therapeutic strategy to limit atherosclerosis and other disorders involving endothelial inflammation.

Discontinuation of statins in routine care settings: a cohort study

BACKGROUND

Systematic data on discontinuation of statins in routine practice of medicine are limited.

OBJECTIVE

To investigate the reasons for statin discontinuation and the role of statin-related events (clinical events or symptoms believed to have been caused by statins) in routine care settings.

DESIGN

A retrospective cohort study.

SETTING

Practices affiliated with Brigham and Women's Hospital and Massachusetts General Hospital in Boston.

PATIENTS

Adults who received a statin prescription between 1 January 2000 and 31 December 2008.

MEASUREMENTS

Information on reasons for statin discontinuations was obtained from a combination of structured electronic medical record entries and analysis of electronic provider notes by validated software.

RESULTS

Statins were discontinued at least temporarily for 57 292 of 107 835 patients. Statin-related events were documented for 18 778 (17.4%) patients. Of these, 11 124 had statins discontinued at least temporarily; 6579 were rechallenged with a statin over the subsequent 12 months. Most patients who were rechallenged (92.2%) were still taking a statin 12 months after the statin-related event. Among the 2721 patients who were rechallenged with the same statin to which they had a statin-related event, 1295 were receiving the same statin 12 months later, and 996 of them were receiving the same or a higher dose.

LIMITATIONS

Statin discontinuations and statin-related events were assessed in practices affiliated with 2 academic medical centers. Utilization of secondary data could have led to missing or misinterpreted data. Natural-language-processing tools used to compensate for the low (30%) proportion of reasons for statin discontinuation documented in structured electronic medical record fields are not perfectly accurate.

CONCLUSION

Statin-related events are commonly reported and often lead to statin discontinuation. However, most patients who are rechallenged can tolerate statins long-term. This suggests that many of the statin-related events may have other causes, are tolerable, or may be specific to individual statins rather than the entire drug class.

PRIMARY FUNDING SOURCE

National Library of Medicine, Diabetes Action Research and Education Foundation, and Chinese National Key Program of Clinical Science.