Relationship of apolipoprotein(a) isoform size with clearance and production of lipoprotein(a) in a diverse cohort

Lipoprotein(a) [Lp(a)] has two main proteins, apoB100 and apo(a). High levels of Lp(a) confer an increased risk for atherosclerotic cardiovascular disease. Most people have two circulating isoforms of apo(a) differing in their molecular mass, determined by the number of Kringle IV Type 2 repeats. Previous studies report a strong inverse relationship between Lp(a) levels and apo(a) isoform sizes. The roles of Lp(a) production and fractional clearance and how ancestry affects this relationship remain incompletely defined. We therefore examined the relationships of apo(a) size with Lp(a) levels and both apo(a) fractional clearance rates (FCR) and production rates (PR) in 32 individuals not on lipid-lowering treatment. We determined plasma Lp(a) levels and apo(a) isoform sizes, and used the relative expression of the two isoforms to calculate a "weighted isoform size" (wIS). Stable isotope studies were performed, using D3-leucine, to determine the apo(a) FCR and PR. As expected, plasma Lp(a) concentrations were inversely correlated with wIS (R2 = 0.27; P = 0.002). The wIS had a modest positive correlation with apo(a) FCR (R2 = 0.10, P = 0.08), and a negative correlation with apo(a) PR (R2 = 0.11; P = 0.06). The relationship between wIS and PR became significant when we controlled for self-reported race and ethnicity (SRRE) (R2 = 0.24, P = 0.03); controlling for SRRE did not affect the relationship between wIS and FCR. Apo(a) wIS plays a role in both FCR and PR; however, adjusting for SRRE strengthens the correlation between wIS and PR, suggesting an effect of ancestry.

Correction: Personalized glucose forecasting for type 2 diabetes using data assimilation

[This corrects the article DOI: 10.1371/journal.pcbi.1005232.].

Progress and perspectives in plant sterol and plant stanol research

Current evidence indicates that foods with added plant sterols or stanols can lower serum levels of low-density lipoprotein cholesterol. This review summarizes the recent findings and deliberations of 31 experts in the field who participated in a scientific meeting in Winnipeg, Canada, on the health effects of plant sterols and stanols. Participants discussed issues including, but not limited to, the health benefits of plant sterols and stanols beyond cholesterol lowering, the role of plant sterols and stanols as adjuncts to diet and drugs, and the challenges involved in measuring plant sterols and stanols in biological samples. Variations in interindividual responses to plant sterols and stanols, as well as the personalization of lipid-lowering therapies, were addressed. Finally, the clinical aspects and treatment of sitosterolemia were reviewed. Although plant sterols and stanols continue to offer an efficacious and convenient dietary approach to cholesterol management, long-term clinical trials investigating the endpoints of cardiovascular disease are still lacking.

P4608BET-inhibition with Apabetalone in Post-ACS Patients with Diabetes: Design and Baseline Characteristics of the BETonMACE trial

Background

Diabetes (DM) is associated with increased risk of macro/microvascular disease and cognitive decline. Inflammation and vascular calcification may be contributing factors. Bromodomain and extraterminal (BET) proteins coordinate gene transcription and modify the transcriptional response to hyperglycemia, and inflammation. Apabetalone competitively and selectively inhibits binding between BET proteins and acetyl-lysine marks on histone tails: normalizing transcriptional profiles to physiological levels; reducing in vitro alkaline phosphatase (ALP) transcription and in vivo plasma ALP in a dose-dependent manner. Phase 2 trials with apabetalone show improved renal function in the chronic kidney disease (CKD) subgroups. Furthermore, treatment showed a 55% reduction in CVD events with more pronounced benefit among patients with DM, low HDL-cholesterol (HDL-C) and high sensitivity C-reactive protein (hsCRP).

Methods

The double-blind, placebo controlled phase 3 BETonMACE trial is testing the hypothesis that apabetalone 100 mg b.i.d., added to standard care, reduces major adverse cardiovascular events (MACE: CV death, non-fatal myocardial infarction or stroke) in patients with DM, acute coronary syndrome (ACS) within the preceding 7–90 days, low HDL-C (<40 mg/dL in men; <45 mg/dL in women), and estimated glomerular filtration rate (eGFR) >30 mL/min/1.7m2. The trial will continue until at least 250 MACE, providing 80% power to detect a 30% reduction. Secondary endpoints include changes in eGFR in patients with baseline eGFR 30 to <60 mL/min/1.7m2, inflammatory markers, lipids, and ALP. In addition the Montreal Cognition Assessment (MoCA) test was performed in patients ≥70 years of age at baseline and annually.

Results

Enrollment of 2425 patients across 13 countries and 195 centers is now complete. Baseline characteristics [median (IQR)] include LDL-C 65.0 (36) mg/dL, HDL-C 33.0 (7) mg/dL, HbA1c 7.3 (2.3) %, hsCRP 2.8 (4.9) mg/L, mean blood pressure 129/76 mmHg, and CKD in 266 patients (10.8%). Background care was based on guideline recommendations. Diabetes medications include metformin (79%), insulin (36%), sulfonylureas (28%), DPP4 inhibitors (11%), SGLT2 inhibitors (9.7%) and GLP1 receptor agonists (0.3%). The CKD subpopulation vs. total population differed significantly from the whole population with regard to age (71 vs. 62 y. o.), male sex (58% vs. 75%), history of hypertension (46% vs. 88%), history of stroke (1.5% vs. 7.5%), and current smokers (6.1% vs. 13%). In the 70 year and older (n=466, 19%) population 54% (n=243) showed a baseline MoCA score 25 and lower suggesting cognitive impairment.

Summary

The BETonMACE trial is testing the hypothesis that selective BET-inhibition with apabetalone, added to established, evidence-based treatment, reduces MACE in high-risk patients with DM, recent ACS, and low HDL-C. The study will also assess apabetalone's effect on renal function and cognition.

Rationale and design of the Pemafibrate to Reduce Cardiovascular Outcomes by Reducing Triglycerides in Patients with Diabetes (PROMINENT) study

Observational, genetic, and experimental data indicate that triglyceride rich lipoproteins (TRLs) likely participate causally in atherothrombosis. Yet, robust clinical trial evidence that triglyceride (TG) lowering therapy reduces cardiovascular events remains elusive. The selective peroxisome proliferator-activated receptor alpha modulator (SPPARM-α), pemafibrate, will be used to target residual cardiovascular risk remaining after treatment to reduce low-density lipoprotein cholesterol (LDL-C) in individuals with the dyslipidemia of type 2 diabetes mellitus (T2). The PROMINENT study will randomly allocate approximately 10,000 participants with T2D, mild-to-moderate hypertriglyceridemia (TG: 200-499 mg/dl; 2.26-5.64 mmol/l) and low high-density lipoprotein cholesterol levels (HDL-C: ≤40 mg/dl; 1.03 mmol/l) to either pemafibrate (0.2 mg twice daily) or matching placebo with an average expected follow-up period of 3.75 years (total treatment phase 5 years; 24 countries). At study entry, participants must be receiving either moderate-to-high intensity statin therapy or meet specified LDL-C criteria. The study population will be one-third primary and two-thirds secondary prevention (established cardiovascular disease). The primary endpoint is a composite of nonfatal myocardial infarction, nonfatal ischemic stroke, hospitalization for unstable angina requiring urgent coronary revascularization, and cardiovascular death. This event-driven study will complete when 1092 adjudicated primary endpoints have accrued with at least 200 occurring in women. Statistical power is at least 90% to detect an 18% reduction in the primary endpoint. Pre-specified secondary and tertiary endpoints include all-cause mortality, hospitalization for heart failure, new or worsening peripheral artery disease, new or worsening diabetic retinopathy and nephropathy, and change in biomarkers including select lipid and non-lipid biomarkers, inflammatory and glycemic parameters.

Advanced Glycation End Products, Oxidation Products, and Incident Cardiovascular Events in Patients With Type 2 Diabetes

OBJECTIVE

The goal of this study was to determine whether plasma levels of advanced glycation end products (AGE) and oxidation products (OP) predict the incidence of cardiovascular disease (CVD) in type 2 diabetes.

RESEARCH DESIGN AND METHODS

Five specific AGE (methylglyoxal hydroimidazolone, carboxymethyl lysine, carboxyethyl lysine, 3-deoxyglucosone hydroimidazolone, and glyoxal hydroimidazolone) and two OP (2-aminoadipic acid and methionine sulfoxide [MetSO]) were measured at baseline in two intensive glucose-lowering studies: 1) a subcohort of the Veterans Affairs Diabetes Trial (VADT) (n = 445) and 2) a nested case-control subgroup from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study (n = 271).

RESULTS

Increased levels of several AGE and OP were associated with older age, decreased kidney function, previous CVD, and longer diabetes duration, but not with hemoglobin A_1c. In the VADT, increased risk of incident CVD events (n = 107) was associated with lower MetSO after adjusting for age, race/ethnicity, sex, prior CVD event, kidney function, treatment assignment, and diabetes duration (hazard ratio [HR] 0.53; 95% CI 0.28-0.99; P = 0.047). Individuals with both low MetSO and high 3-deoxyglucosone hydroimidazolone concentrations were at highest risk for CVD (HR 1.70; P = 0.01). In the ACCORD study, those with incident CVD events (n = 136) had lower MetSO (by 14%; P = 0.007) and higher glyoxal hydroimidazolone and carboxymethyl lysine (by 18% and 15%, respectively; P = 0.04 for both); however, only the difference in MetSO remained significant after adjustment for prior CVD event (P = 0.002).

CONCLUSIONS

Lower levels of MetSO and higher levels of select AGE are associated with increased incident CVD and may help account for the limited benefit of intensive glucose lowering in type 2 diabetes.

Clinically Feasible Microstructural MRI to Quantify Cervical Spinal Cord Tissue Injury Using DTI, MT, and T2*-Weighted Imaging: Assessment of Normative Data and Reliability

BACKGROUND AND PURPOSE

DTI, magnetization transfer, T2*-weighted imaging, and cross-sectional area can quantify aspects of spinal cord microstructure. However, clinical adoption remains elusive due to complex acquisitions, cumbersome analysis, limited reliability, and wide ranges of normal values. We propose a simple multiparametric protocol with automated analysis and report normative data, analysis of confounding variables, and reliability.

MATERIALS AND METHODS

Forty healthy subjects underwent T2WI, DTI, magnetization transfer, and T2*WI at 3T in <35 minutes using standard hardware and pulse sequences. Cross-sectional area, fractional anisotropy, magnetization transfer ratio, and T2*WI WM/GM signal intensity ratio were calculated. Relationships between MR imaging metrics and age, sex, height, weight, cervical cord length, and rostrocaudal level were analyzed. Test-retest coefficient of variation measured reliability in 24 DTI, 17 magnetization transfer, and 16 T2*WI datasets. DTI with and without cardiac triggering was compared in 10 subjects.

RESULTS

T2*WI WM/GM showed lower intersubject coefficient of variation (3.5%) compared with magnetization transfer ratio (5.8%), fractional anisotropy (6.0%), and cross-sectional area (12.2%). Linear correction of cross-sectional area with cervical cord length, fractional anisotropy with age, and magnetization transfer ratio with age and height led to decreased coefficients of variation (4.8%, 5.4%, and 10.2%, respectively). Acceptable reliability was achieved for all metrics/levels (test-retest coefficient of variation < 5%), with T2*WI WM/GM comparing favorably with fractional anisotropy and magnetization transfer ratio. DTI with and without cardiac triggering showed no significant differences for fractional anisotropy and test-retest coefficient of variation.

CONCLUSIONS

Reliable multiparametric assessment of spinal cord microstructure is possible by using clinically suitable methods. These results establish normalization procedures and pave the way for clinical studies, with the potential for improving diagnostics, objectively monitoring disease progression, and predicting outcomes in spinal pathologies.

A Novel MRI Biomarker of Spinal Cord White Matter Injury: T2*-Weighted White Matter to Gray Matter Signal Intensity Ratio

BACKGROUND AND PURPOSE

T2*-weighted imaging provides sharp contrast between spinal cord GM and WM, allowing their segmentation and cross-sectional area measurement. Injured WM demonstrates T2*WI hyperintensity but requires normalization for quantitative use. We introduce T2*WI WM/GM signal-intensity ratio and compare it against cross-sectional area, the DTI metric fractional anisotropy, and magnetization transfer ratio in degenerative cervical myelopathy.

MATERIALS AND METHODS

Fifty-eight patients with degenerative cervical myelopathy and 40 healthy subjects underwent 3T MR imaging, covering C1-C7. Metrics were automatically extracted at maximally compressed and uncompressed rostral/caudal levels. Normalized metrics were compared with t tests, area under the curve, and logistic regression. Relationships with clinical measures were analyzed by using Pearson correlation and multiple linear regression.

RESULTS

The maximally compressed level cross-sectional area demonstrated superior differences (P = 1 × 10^-13), diagnostic accuracy (area under the curve = 0.890), and univariate correlation with the modified Japanese Orthopedic Association score (0.66). T2*WI WM/GM showed strong differences (rostral: P = 8 × 10^-7; maximally compressed level: P = 1 × 10^-11; caudal: P = 1 × 10^-4), correlations (modified Japanese Orthopedic Association score; rostral: -0.52; maximally compressed level: -0.59; caudal: -0.36), and diagnostic accuracy (rostral: 0.775; maximally compressed level: 0.860; caudal: 0.721), outperforming fractional anisotropy and magnetization transfer ratio in most comparisons and cross-sectional area at rostral/caudal levels. Rostral T2*WI WM/GM showed the strongest correlations with focal motor (-0.45) and sensory (-0.49) deficits and was the strongest independent predictor of the modified Japanese Orthopedic Association score (P = .01) and diagnosis (P = .02) in multivariate models (R² = 0.59, P = 8 × 10^-13; area under the curve = 0.954, respectively).

CONCLUSIONS

T2*WI WM/GM shows promise as a novel biomarker of WM injury. It detects damage in compressed and uncompressed regions and contributes substantially to multivariate models for diagnosis and correlation with impairment. Our multiparametric approach overcomes limitations of individual measures, having the potential to improve diagnostics, monitor progression, and predict outcomes.

Personalized glucose forecasting for type 2 diabetes using data assimilation

Type 2 diabetes leads to premature death and reduced quality of life for 8% of Americans. Nutrition management is critical to maintaining glycemic control, yet it is difficult to achieve due to the high individual differences in glycemic response to nutrition. Anticipating glycemic impact of different meals can be challenging not only for individuals with diabetes, but also for expert diabetes educators. Personalized computational models that can accurately forecast an impact of a given meal on an individual's blood glucose levels can serve as the engine for a new generation of decision support tools for individuals with diabetes. However, to be useful in practice, these computational engines need to generate accurate forecasts based on limited datasets consistent with typical self-monitoring practices of individuals with type 2 diabetes. This paper uses three forecasting machines: (i) data assimilation, a technique borrowed from atmospheric physics and engineering that uses Bayesian modeling to infuse data with human knowledge represented in a mechanistic model, to generate real-time, personalized, adaptable glucose forecasts; (ii) model averaging of data assimilation output; and (iii) dynamical Gaussian process model regression. The proposed data assimilation machine, the primary focus of the paper, uses a modified dual unscented Kalman filter to estimate states and parameters, personalizing the mechanistic models. Model selection is used to make a personalized model selection for the individual and their measurement characteristics. The data assimilation forecasts are empirically evaluated against actual postprandial glucose measurements captured by individuals with type 2 diabetes, and against predictions generated by experienced diabetes educators after reviewing a set of historical nutritional records and glucose measurements for the same individual. The evaluation suggests that the data assimilation forecasts compare well with specific glucose measurements and match or exceed in accuracy expert forecasts. We conclude by examining ways to present predictions as forecast-derived range quantities and evaluate the comparative advantages of these ranges.

Lipid changes during basal insulin peglispro, insulin glargine, or NPH treatment in six IMAGINE trials

Basal insulin peglispro (BIL) is a novel basal insulin with hepato-preferential action resulting from reduced peripheral effects. This report provides an integrated summary of lipid changes at 26 weeks with BIL and comparator insulins (glargine, NPH) from phase III studies in type 1 diabetes (T1D), insulin-naïve patients with type 2 diabetes (T2D), patients with T2D on basal insulin only and patients with T2D on basal-bolus therapy. BIL treatment had little effect on HDL cholesterol and LDL cholesterol in all patients. The effect of both BIL and glargine treatment on triglycerides (TG) depended on whether patients had been previously treated with insulin. When BIL replaced conventional insulin glargine or NPH treatments, increases in TG levels were observed. When BIL or comparator insulins were given for 26 weeks to insulin-naïve patients with T2D, TG levels were unchanged from baseline with BIL but decreased with either glargine or NPH. The decreased peripheral action of BIL may reduce suppression of lipolysis in peripheral adipose tissue resulting in increased free fatty acid delivery to the liver and, hence, increased hepatic TG synthesis and secretion.

Targeted Proteomics Identifies Paraoxonase/Arylesterase 1 (PON1) and Apolipoprotein Cs as Potential Risk Factors for Hypoalphalipoproteinemia in Diabetic Subjects Treated with Fenofibrate and Rosiglitazone

Low levels of high-density lipoprotein cholesterol (HDL-C) and high triglyceride levels contribute to the excess rate of cardiovascular events seen in subjects with type 2 diabetes. Fenofibrate treatment partially reverses dyslipidemia in these subjects. However, a paradoxical marked reduction in HDL-C and HDL's major protein, apolipoprotein A-I, is a complication of fenofibrate in combination with rosiglitazone, an insulin-sensitizing agent. Risk factors for this condition, termed hypoalphalipoproteinemia, have yet to be identified. Using a case-control study design with subjects enrolled in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial, we tested the hypothesis that alterations in HDL's protein cargo predispose diabetic subjects to fenofibrate/rosiglitazone-induced hypoalphalipoproteinemia. HDL was isolated from blood obtained from controls (no decreases or increase in HDL-C while receiving fenofibrate/rosiglitazone therapy) and cases (developed hypoalphalipoproteinemia after fenofibrate/rosiglitazone treatment) participating in the ACCORD study before they began fenofibrate/rosiglitazone treatment. HDL proteins were quantified by targeted parallel reaction monitoring (PRM) and selected reaction monitoring (SRM) with isotope dilution. This approach demonstrated marked increases in the relative concentrations of paraoxonase/arylesterase 1 (PON1), apolipoprotein C-II (APOC2), apolipoprotein C-I, and apolipoprotein H in the HDL of subjects who developed hypoalphalipoproteinemia. The case and control subjects did not differ significantly in baseline HDL-C levels or other traditional lipid risk factors. We used orthogonal biochemical techniques to confirm increased levels of PON1 and APOC2. Our observations suggest that an imbalance in HDL proteins predisposes diabetic subjects to develop hypoalphalipoproteinemia on fenofibrate/rosiglitazone therapy.

Adult outcomes of three newborns with a combined weight of 1100 grams

OBJECTIVE

To present the short- and long-term (20 years) growth and developmental outcomes of four micropremies (birth weight of less than 500 grams).

METHOD

Retrospective review of medical records and prospective assessment/interview with patients and their families.

RESULTS

One infant was lost at long-term follow-up. The other three showed a quite satisfactory health status and life style in early adulthood.

CONCLUSIONS

Despite extreme low birth weight (less than 500 grams) normal outcomes are possible. In the case of micropremies, gestational age appears to be of greater importance than birth weight as well as female gender in the decision-making process regarding initiation of resuscitation.

Abstract 628: Hepatic Insulin Signaling Regulates ApoA-I Gene Expression Through the Type I Deiodinase

People with low levels of high density lipoprotein cholesterol (HDLC) and apolipoprotein A-I (ApoA-I) have a higher risk of cardiovascular disease. Low levels of HDLC are common in individuals who are insulin resistant (IR), e.g., with metabolic syndrome and type 2 diabetes mellitus (T2DM). Despite the high prevalence of these two disorders, very little work has been reported regarding the molecular pathways linking insulin signaling or action and the levels of either HDLC or ApoA-1. We reported previously that liver specific insulin receptor (InsR) knockout mice (LIRKO) have markedly reduced plasma HDLC levels that increase after restoration of hepatic Akt signaling. In the present study, we created acute LIRKO mice by injecting an albumin-Cre adenovirus (Ad) into InsR floxed mice and observed marked reductions in HDLC, the expression of ApoA-I, and the expression of the gene coding Type1 iodothyronine deiodinase1, a selenoenzyme expressed highly in the liver that converts thyroxine to 3,5,3’-triiodothyronine (T3) or reverse T3. Deiodinase 1 knockout mice also had significantly reduced hepatic ApoA-I mRNA levels. Overexpression of Dio1 in LIRKO restored HDLC and significantly increased the expression of ApoA-I mRNA. In vitro studies showed that the expression of ApoA-I was significantly reduced after knockdown of either InsR or Dio1 expression in HepG2 cells. Moreover, overexpression of Dio1 restored ApoA-I promoter activity that had been decreased by knockdown of InsR. Deletion analysis of ApoAI promoter regions showed that insulin signaling regulated ApoA-I expression by acting on a region which does not contain any thyroid response elements. Pulse-chase experiments in HepG2 cells showed that deficiency of insulin signaling resulted in decreased synthesis and secretion of ApoAI. Our results indicates that defective hepatic insulin signaling results in reduced expression of Dio1 which, in turn, leads to reduced expression of ApoA-I and decreased synthesis and secretion of ApoA-I from hepatocytes. We believe our studies have defined a novel pathway from insulin signaling to ApoA-I synthesis that may lead to new approaches for increasing HDL levels in people with defective insulin signaling.

Genetic dissection of retinoid esterification and accumulation in the liver and adipose tissue

Approximately 80-90% of all retinoids in the body are stored as retinyl esters (REs) in the liver. Adipose tissue also contributes significantly to RE storage. The present studies, employing genetic and nutritional interventions, explored factors that are responsible for regulating RE accumulation in the liver and adipose tissue and how these influence levels of retinoic acid (RA) and RA-responsive gene expression. Our data establish that acyl-CoA:retinol acyltransferase (ARAT) activity is not involved in RE synthesis in the liver, even when mice are nutritionally stressed by feeding a 25-fold excess retinol diet or upon ablation of cellular retinol-binding protein type I (CRBPI), which is proposed to limit retinol availability to ARATs. Unlike the liver, where lecithin:retinol acyltransferase (LRAT) is responsible for all RE synthesis, this is not true for adipose tissue where Lrat-deficient mice display significantly elevated RE concentrations. However, when CrbpI is also absent, RE levels resemble wild-type levels, suggesting a role for CrbpI in RE accumulation in adipose tissue. Although expression of several RA-responsive genes is elevated in Lrat-deficient liver, employing a sensitive liquid chromatography tandem mass spectrometry protocol and contrary to what has been assumed for many years, we did not detect elevated concentrations of all-trans-RA. The elevated RA-responsive gene expression was associated with elevated hepatic triglyceride levels and decreased expression of Pparδ and its downstream Pdk4 target, suggesting a role for RA in these processes in vivo.

Statins in cardiometabolic disease: what makes pitavastatin different?

The term cardiometabolic disease encompasses a range of lifestyle-related conditions, including Metabolic syndrome (MetS) and type 2 diabetes (T2D), that are characterized by different combinations of cardiovascular (CV) risk factors, including dyslipidemia, abdominal obesity, hypertension, hyperglycemia/insulin resistance, and vascular inflammation. These risk factors individually and interdependently increase the risk of CV and cerebrovascular events, and represent one of the biggest health challenges worldwide today. CV diseases account for almost 50% of all deaths in Europe and around 30% of all deaths worldwide. Furthermore, the risk of CV death is increased twofold to fourfold in people with T2D. Whilst the clinical management of CV disease has improved in Western Europe, the pandemic of obesity and T2D reduces the impact of these gains. This, together with the growing, aging population, means the number of CV deaths is predicted to increase from 17.1 million worldwide in 2004 to 23.6 million in 2030. The recommended treatment for MetS is lifestyle change followed by treatment for the individual risk factors. Numerous studies have shown that lowering low-density lipoprotein-cholesterol (LDL-C) levels using statins can significantly reduce CV risk in people with and without T2D or MetS. However, the risk of major vascular events in those attaining the maximum levels of LDL-C-reduction is only reduced by around one-third, which leaves substantial residual risk. Recent studies suggest that low high-density lipoprotein-cholesterol (HDL-C) (<1 .0 mmol/l; 40 mg/dl) and high triglyceride levels (≥1.7 mmol/l; 150 mg/dl) are independent risk factors for CV disease and that the relationship between HDL-C and CV risk persists even when on-treatment LDL-C levels are low (<1.7 mmol/l; 70 mg/dl). European guidelines highlight the importance of reducing residual risk by targeting these risk factors in addition to LDL-C. This is particularly important in patients with T2D and MetS because obesity and high levels of glycated hemoglobin are directly related to low levels of HDL-C and high triglyceride. Although most statins have a similar low-density lipoprotein-lowering efficacy, differences in chemical structure and pharmacokinetic profile can lead to variations in pleiotropic effects (for example, high-density lipoprotein-elevating efficacy), adverse event profiles, and drug-drug interactions. The choice of statin should therefore depend on the needs of the individual patient. The following reviews will discuss the potential benefits of pitavastatin versus other statins in the treatment of patients with dyslipidemia and MetS or T2D, focusing on its effects on HDL-C quantity and quality, its potential impact on atherosclerosis and CV risk, and its metabolic characteristics that reduce the risk of drug interactions. Recent controversies surrounding the potentially diabetogenic effects of statins will also be discussed.

Abstract 329: Mechanism by Which Anacetrapib Lowers Plasma Lipoprotein (a) Concentration

Objective: Anacetrapib, a CETP inhibitor, was previously shown to decrease plasma lipoprotein (a) [Lp(a)] levels by 35-40% in subjects also taking a statin. Thus, anacetrapib is an efficacious Lp(a)-lowering agent. The goal of this study was to define the mechanism by which anacetrapib lowers plasma Lp(a) levels.

Methods: 39 moderately hyperlipidemic volunteers were enrolled in a fixed-sequence study, in which 75% were on atorvastatin 20mg/day, plus placebo for four weeks (period 1), and then atorvastatin plus anacetrapib (100 mg/day) for 8 weeks (period 2). The other 25% of the subjects received double placebo for four weeks, and then placebo plus anacetrapib for 8 weeks. Turnover studies using D3-leucine were performed at the end of each period. The present analysis utilized samples from a subset of subjects (n=12) who had plasma Lp(a) levels greater than 10 nM at the end of period 1 and had a greater than 10% reduction in Lp(a) by the end of period 2. The fractional synthetic rate (FSR:equal to fractional catabolic rate at steady state) of mature Lp(a), isolated from a D:1.019-1.21 g/ml density interval, was determined from the enrichment of a leucine-containing peptide specific to apo(a). The production rate (PR) of mature Lp(a) was calculated from the FSR and the Lp(a) pool size. To date, we have calculated the FSR and PR in 4 participants.

Results: Baseline Lp(a) mean levels were 45.7 ± 6.3nM in the entire group and 56.5 ± 33.6nM in the 12 qualifying subjects. Anacetrapib lowered Lp(a) by 43 ± 22% in the 12 subjects and 21 ±12% in the 4 subjects with turnover data. In these 4 subjects, the reduction in mature Lp(a) was associated with a 24% reduction in FSR and a 41% reduction in PR. Lp(a) kinetics analyses of the remaining 8 subjects are in progress.

Conclusion: These preliminary results suggest that anacetrapib decreases Lp(a) levels by significantly decreasing the production of mature Lp(a). Additional analyses are planned to determine if the reduced production of Lp(a) results from decreased entry of Lp(a) into plasma or reduced conversion of a precursor form to the mature Lp(a).

Abstract 25: Inhibition of VLDL Assembly by Apolipoprotein B Antisense Oligonucleotides Stimulates Autophagy

In order to investigate the effects of reduced VLDL secretion on hepatic lipid metabolism, we examined the effects of knockdown of either apolipoproteinB (apoB) or microsomal triglyceride transfer protein (MTP) using antisense oligonucleotides (ASO) for 6 weeks in apobec-1 knockout mice that only synthesize apoB100. Despite a similar decrease VLDL secretion in mice treated with apoB ASO as compared with MTP ASO, there was an increase in liver triglyceride (TG) content only in the MTP ASO-treated mice. There were no differences in either fatty acid (FA) uptake or secretion, or lipid synthesis from de novo lipogenesis, between the two groups to explain the difference in liver TG mass. In primary hepatocytes isolated from mice treated with apoB ASO, FA oxidation measured after a 16 hr steady state label with 14 C oleic acid showed a 3 fold increase in FA oxidation versus cells from control ASO-treated mice. A labeled time course study showed that the increase in FA oxidation was delayed, indicating compartmentalization of lipid in the apoB ASO-treated hepatocytes. Electron microsopy (EM) showed swollen endoplasmic reticulum (ER) and increased autophagosomes in the apoB ASO hepatocytes. The latter was confirmed by an increase in immunofluoresent staining for the autophagy marker LC3b. The LC3b protein was perinuclear suggesting that it was present on mature autophagolysosomes. Treatment with lysosomal inhibitors showed that the accumulation of LC3b was not due to a defect in autophagic flux in these hepatocytes. Autophagosomes in the EMs contained large double membrane structures suggestive of ER. In primary hepatocytes from apoB ASO-treated mice, labeling with ER Tracker showed abnormal aggregates of ER. In addition, immunofluorescent staining studies showed that these abnormal ER aggregates, as represented by calnexin staining, co-localized with the LC3b protein. We propose that autophagy of lipid-filled ER, with subsequent lipolysis of TG in the autophagolysosome and later oxidation of released FA, prevent hepatic steatosis in mice treated with apoB ASO.

Preparedness of the CTSA's structural and scientific assets to support the mission of the National Center for Advancing Translational Sciences (NCATS)

The formation of the National Center for Advancing Translational Sciences (NCATS) brings new promise for moving basic science discoveries to clinical practice, ultimately improving the health of the nation. The Clinical and Translational Science Award (CTSA) sites, now housed with NCATS, are organized and prepared to support in this endeavor. The CTSAs provide a foundation for capitalizing on such promise through provision of a disease-agnostic infrastructure devoted to clinical and translational (C&T) science, maintenance of training programs designed for C&T investigators of the future, by incentivizing institutional reorganization and by cultivating institutional support.

The ACCORD-Lipid study: implications for treatment of dyslipidemia in Type 2 diabetes mellitus

Patients with Type 2 diabetes mellitus (T2DM) are at high risk of developing cardiovascular disease (CVD). Treatment of diabetic dyslipidemia, comprised mainly of hypertriglyceridemia, and low HDL-C, with either statin or fibrate monotherapy, is moderately effective at reversing the abnormal lipid levels, but does not completely reverse the risk of CVD. Combination therapy with a statin and fibrate more effectively treats diabetic dyslipidemia; however, neither the impact on CVD risk nor the safety profile of statin-fibrate combined treatment had been tested in a large randomized trial. The Action to Control Cardiovascular Risk in Diabetes (ACCORD)-Lipid trial tested the hypothesis that combination therapy with a fibrate and statin would more effectively prevent major CVD events in a high-risk population of patients with T2DM compared with statin monotherapy. In ACCORD-Lipid, over 5000 patients were treated with fenofibrate plus simvastatin versus simvastatin alone. Although combination therapy did not significantly reduce CVD event rates in the ACCORD-Lipid cohort as a whole, a predefined subgroup of participants with the combination of significant hypertriglyceridemia and low HDL-C experienced a 31% lower event rate with combination therapy. Post hoc analyses conducted in similar subsets in previous fibrate monotherapy trials were concordant with these findings in ACCORD-Lipid. Combination therapy was well tolerated and safe, with no detectable increase in myopathy. The implications of the ACCORD-Lipid findings for the treatment of dyslipidemia in patients with T2DM are discussed.

Role of fibrates in cardiovascular disease prevention, the ACCORD-Lipid perspective

PURPOSE OF REVIEW

To examine the results of the Action to Control Cardiovascular Risk in Diabetes (ACCORD)-Lipid trial, particularly the subgroup analyses. It is important, when a study fails to meet its overall primary endpoint, to ensure that interpretation of the results include analyses of subgroups that might benefit from the treatment tested. The goal of this review, therefore, is to provide insight and advice to physicians and healthcare workers treating patients similar to those enrolled in ACCORD.

RECENT FINDINGS

The recently published results of ACCORD-Lipid trial will be presented upon the background of previous trials that have tested the ability of fibrates to lower cardiovascular risk.

SUMMARY

Although ACCORD-Lipid trial did not provide support for the general addition of fenofibrate to statin-treated patients with type 2 diabetes mellitus (T2DM), it added significantly to the results from fibrate monotherapy trials indicative of benefit from such treatment in subgroups of patients who present with significant dyslipidemia. In particular, ACCORD-Lipid trial, in our view, supports the addition of fenofibrate to statin therapy in patients with T2DM and optimal low-density lipoprotein cholesterol levels but persistent, significant hypertriglyceridemia (>200 mg/dl) and low high-density lipoprotein cholesterol levels (<35-40 mg/dl).

Lipoprotein(a) as a cardiovascular risk factor: current status

AIMS

The aims of the study were, first, to critically evaluate lipoprotein(a) [Lp(a)] as a cardiovascular risk factor and, second, to advise on screening for elevated plasma Lp(a), on desirable levels, and on therapeutic strategies.

METHODS AND RESULTS

The robust and specific association between elevated Lp(a) levels and increased cardiovascular disease (CVD)/coronary heart disease (CHD) risk, together with recent genetic findings, indicates that elevated Lp(a), like elevated LDL-cholesterol, is causally related to premature CVD/CHD. The association is continuous without a threshold or dependence on LDL- or non-HDL-cholesterol levels. Mechanistically, elevated Lp(a) levels may either induce a prothrombotic/anti-fibrinolytic effect as apolipoprotein(a) resembles both plasminogen and plasmin but has no fibrinolytic activity, or may accelerate atherosclerosis because, like LDL, the Lp(a) particle is cholesterol-rich, or both. We advise that Lp(a) be measured once, using an isoform-insensitive assay, in subjects at intermediate or high CVD/CHD risk with premature CVD, familial hypercholesterolaemia, a family history of premature CVD and/or elevated Lp(a), recurrent CVD despite statin treatment, ≥3% 10-year risk of fatal CVD according to European guidelines, and/or ≥10% 10-year risk of fatal + non-fatal CHD according to US guidelines. As a secondary priority after LDL-cholesterol reduction, we recommend a desirable level for Lp(a) <80th percentile (less than ∼50 mg/dL). Treatment should primarily be niacin 1-3 g/day, as a meta-analysis of randomized, controlled intervention trials demonstrates reduced CVD by niacin treatment. In extreme cases, LDL-apheresis is efficacious in removing Lp(a).

CONCLUSION

We recommend screening for elevated Lp(a) in those at intermediate or high CVD/CHD risk, a desirable level <50 mg/dL as a function of global cardiovascular risk, and use of niacin for Lp(a) and CVD/CHD risk reduction.

Development of apolipoprotein B antisense molecules as a therapy for hyperlipidemia

As new studies demonstrate that lower levels of low-density lipoprotein cholesterol (LDL-C) reduce cardiovascular disease, and as goals for LDL-C in high-risk individuals are reduced further and further, reaching those goals becomes more difficult for a significant percentage of the population. New therapeutic approaches to lower LDL-C would, therefore, be advantageous, particularly in those who are most likely to suffer cardiovascular disease-associated morbidity and mortality. Mouse and human genetic models suggest that decreasing hepatic apolipoprotein B (apoB) production may be a therapeutic approach for the treatment of dyslipidemia. Because antisense oligonucleotides naturally distribute to the liver and can specifically inhibit synthesis of proteins from their messenger RNAs, antisense oligonucleotides represent a potential approach for decreasing the biosynthesis of apoB, and thereby, the production of both very low density lipoprotein (VLDL) and LDL. Newly developed apoB antisense approaches have produced results in animal models and humans, providing proof of concept regarding reductions in LDL-C concentrations. Surprisingly, despite prior experience with inhibitors of microsomal triglyceride transfer protein, which also inhibits the secretion of VLDL, apoB antisense-mediated reduction in VLDL secretion does not appear to cause marked steatosis. The mechanisms whereby two different approaches for inhibiting apoB and triglyceride secretion have different effects on hepatic triglycerides are currently being examined.

Biological control of ticks

Ticks have numerous natural enemies, but only a few species have been evaluated as tick biocontrol agents (BCAs). Some laboratory results suggest that several bacteria are pathogenic to ticks, but their mode of action and their potential value as biocontrol agents remain to be determined. The most promising entomopathogenic fungi appear to be Metarhizium anisopliae and Beauveria bassiana, strains of which are already commercially available for the control of some pests. Development of effective formulations is critical for tick management. Entomopathogenic nematodes that are pathogenic to ticks can potentially control ticks, but improved formulations and selection of novel nematode strains are needed. Parasitoid wasps of the genus Ixodiphagus do not typically control ticks under natural conditions, but inundative releases show potential value. Most predators of ticks are generalists, with a limited potential for tick management (one possible exception is oxpeckers in Africa). Biological control is likely to play a substantial role in future IPM programmes for ticks because of the diversity of taxa that show high potential as tick BCAs. Considerable research is required to select appropriate strains, develop them as BCAs, establish their effectiveness, and devise production strategies to bring them to practical use.

Dyslipidemia in pediatric renal disease: epidemiology, pathophysiology, and management

Dyslipidemia increases the risk of cardiovascular events among individuals with renal disease, and there is a growing body of evidence that it hastens the progression of renal disease itself. Children with nephrotic syndrome or renal transplants have easily recognized hyperlipidemia. Among those with chronic renal insufficiency or end-stage renal disease, detection of dyslipidemia requires more careful analysis and knowledge of normal pediatric ranges. Disordered lipoprotein metabolism results from complex interactions among many factors, including the primary disease process, use of medications such as corticosteroids, the presence of malnutrition or obesity, and diet. The systematic treatment of dyslipidemia in children with chronic renal disease is controversial because conclusive data regarding the risks and benefits are lacking. Hepatic 3-methylglutaryl coenzyme A reductase inhibitors (statins), fibrates, plant stanols, bile acid-binding resins, and dietary manipulation are options for individualized treatment. Prospective investigations are required to guide clinical management.

Biologic studies of chimeras of highly and moderately virulent molecular clones of simian immunodeficiency virus SIVsmPBj suggest a critical role for envelope in acute AIDS virus pathogenesis

Previous studies identified three molecular clones of the acutely pathogenic SIVsmPBj strain that varied in terms of relative in vivo pathogenicity. One clone, SIVsmPBj6.6, reproducibly induced a rapidly fatal disease in pigtailed macaques. In contrast, a highly related clone (SIVsmPBj6.9) was only minimally pathogenic in macaques. PBj6.6 and PBj6.9 shared a tyrosine substitution at position 17 in the Nef protein that is a major determinant of virulence but differed at one residue in Vpx (C89R), three residues within the envelope (D119G, R871G, G872R), and a single residue in Nef (F252L). SIVsmPBj6.9 was less efficient in inducing proliferation of resting macaque peripheral blood mononuclear cells in vitro than SIVsmPBj6.6 and exhibited a marked reduction in infectivity relative to SIVsmPBj6.6. Chimeric viruses for each of these variable residues were constructed, and their biologic properties were compared to those of the parental strains. Differences in Vpx and Nef did not alter the basic biologic phenotype of the chimeras. However, the D119G substitution in the envelope of SIVsmPBj6.9 was associated with a marked reduction in the infectivity of this virus relative to SIVsmPBj6.6. An associated processing defect in gp160 of SIVsmPBj6.9 and chimeras expressing the D119G substitution suggests that a reduction in virion envelope incorporation is the mechanistic basis for reduced virion infectivity. In vivo studies revealed that substitution of the PBj6.9 amino acid into PBj6.6 (D119) abrogated the pathogenicity of this previously pathogenic virus. Introduction of the PBj6.9 G119, however, did not confer full virulence to the parental PBj6.9 virus, implicating one or all of the other four substitutions in the virulence of SIVsmPBj6.6.

Long-term cholesterol-lowering effects of psyllium as an adjunct to diet therapy in the treatment of hypercholesterolemia

BACKGROUND

Hypercholesterolemia is a major risk factor for coronary heart disease and nutrition management is the initial therapeutic approach.

OBJECTIVE

This multicenter study evaluated the long-term effectiveness of psyllium husk fiber as an adjunct to diet in the treatment of persons with primary hypercholesterolemia.

DESIGN

Men and women with hypercholesterolemia were recruited. After following an American Heart Association Step I diet for 8 wk (dietary adaptation phase), eligible subjects with serum LDL-cholesterol concentrations between 3.36 and 4.91 mmol/L were randomly assigned to receive either 5.1 g psyllium or a cellulose placebo twice daily for 26 wk while continuing diet therapy.

RESULTS

Serum total and LDL-cholesterol concentrations were 4.7% and 6.7% lower in the psyllium group than in the placebo group after 24-26 wk (P < 0.001). Other outcome measures did not differ significantly between groups.

CONCLUSIONS

Treatment with 5.1 g psyllium twice daily produces significant net reductions in serum total and LDL-cholesterol concentrations in men and women with primary hypercholesterolemia. Psyllium therapy is an effective adjunct to diet therapy and may provide an alternative to drug therapy for some patients.

A review of metabolic and cardiovascular effects of oral antidiabetic agents: beyond glucose-level lowering

It has become evident that cardiovascular disease is the major cause of morbidity and mortality in type 2 diabetes mellitus. This raises the possibility that glucose lowering agents with other nonglucose-lowering effects, might have added benefits. In this review, we focus on the metabolic and cardiovascular effects of oral antidiabetic agents that go beyond glucose-level lowering. Such effects include lipid modifying actions, antithrombotic and profibrinolytic activities, and direct action at the level of the vessel wall to improve endothelial function or prevent smooth muscle hyperplasia. These additional activities, particularly those seen with the newer oral antidiabetic agents, hold the promise of reducing cardiovascular complications beyond that achievable by glucose lowering alone.