Treating dyslipidemia in the high-risk patient

Clinical trials demonstrate that cardiovascular event rates diminish as low-density lipoprotein (LDL)-cholesterol and apolipoprotein B-containing particles are lowered with statin treatment. The relationship between LDL-cholesterol and cardiovascular events seems to be linear, with no lowest threshold. While LDL-cholesterol remains the primary target for coronary heart disease prevention, non-HDL-cholesterol is an important secondary target in patients with mixed dyslipidemia.

CD11c expression in adipose tissue and blood and its role in diet-induced obesity

OBJECTIVE

To examine CD11c, a beta(2)-integrin, on adipose tissue (AT) leukocytes and blood monocytes and its role in diet-induced obesity.

METHODS AND RESULTS

High-fat diet-induced obese C57BL/6 mice, CD11c-deficient mice, and obese humans were studied. CD11c, leukocytes, and chemokines/cytokines were examined in AT and/or blood by flow cytometry, RNase protection assay, quantitative polymerase chain reaction, or enzyme-linked immunosorbent assay. Obese C57BL/6 mice had increased CD11c in AT and blood compared with lean controls. CD11c messenger RNA positively correlated with monocyte chemoattractant protein 1 in human visceral AT. Obese humans with metabolic syndrome had a higher CD11c level on blood monocytes compared with lean humans. Low-fat diet-induced weight loss reduced blood monocyte CD11c in obese mice and humans. Mouse and human monocyte CD11c levels and mouse AT CD11c messenger RNA correlated with insulin resistance. CD11c deficiency in mice did not alter weight gain but decreased inflammation, evidenced by a lower T-cell number and reduced levels of major histocompatibility complex class II, C-C chemokine ligand 2 (CCL5), CCL4, and interferon gamma in AT, and ameliorated insulin resistance and glucose intolerance associated with diet-induced obesity.

CONCLUSIONS

Diet-induced obesity increased CD11c in both AT and blood in mice and humans. CD11c plays an important role in T-cell accumulation and activation in AT, and contributes to insulin resistance associated with obesity.

Rotation detection in light-driven nanorotors

We analyze the rotational dynamics of light driven nanorotors, made of nanotube bundles and gold nanorods aggregates, with nonsymmetric shapes, trapped in optical tweezers. We identify two different regimes depending on dimensions and optical properties of the nanostructures. These correspond to alignment with either the laser propagation axis or the dominant polarization direction, or rotational motions caused by either unbalanced radiation pressure or polarization torque. By analyzing the motion correlations of the trapped nanostructures, we measure with high accuracy both the optical trapping parameters and the rotation frequency induced by the radiation pressure. Our results pave the way to improved all-optical detection, control over rotating nanomachines, and rotation detection in nano-optomechanics.

Cholesterol and coronary events. The current thinking

The clinical benefit of lowering levels of low-density lipoprotein cholesterol (LDL-C) in primary and secondary prevention of coronary heart disease (CHD) is well established, with the statins recognized as the drugs of choice. Updated guidelines from the National Cholesterol Education Program continue to recognize the importance of aggressive LDL-C lowering in patients with established CHD, as well as identifying CHD risk-equivalent patients who require the same aggressive LDL-C reduction in primary prevention. For such patients, optimal LDL-C levels are <100 mg/dL. The issue of whether LDL-C should be lowered substantially below 100 mg/dL in both types of patients remains unresolved but is being addressed by several ongoing end point trials. With existing statins and others expected soon, LDL-C reductions of more than 60% appear possible. The updated guidelines redefine high-density lipoprotein cholesterol (HDL-C) levels <40 mg/dL as a major CHD risk factor in both men and women, and also introduce non-HDL-C as another parameter that predicts CHD risk. Statins effectively reduce the components of non-HDL-C, and some members produce elevations in HDL-C approaching those achieved with fibrates. Accordingly, statin therapy is appropriate for a wide range of dyslipidemic patients.

Sagnac interferometer method for synthesis of fractional polarization vortices

We present a method for producing laser beams of nonuniform polarization where the polarization direction rotates on a trajectory about the beam propagation direction. Our method uses a Sagnac interferometer that incorporates a spatial light modulator to combine beams that possess oppositely charged phase vortices in order to achieve the desired polarization vortex. We demonstrate the utility of our method by producing polarization vortices characterized by a fractional index, and we compare the results with calculations of the expected fields.

Retrospective comparison of the effectiveness of a fenofibrate 145 mg formulation compared with the standard 160 mg tablet

OBJECTIVE

To compare changes in lipid levels (total cholesterol [total-C], low-density lipoprotein cholesterol [LDL-C], triglycerides [TG], and high-density lipoprotein cholesterol [HDL-C]) for patients who switched from standard fenofibrate 160 mg (requiring dosing with food) to fenofibrate 145 mg with no food effect (NFE).

METHODS

The analyses were performed using an electronic medical records dataset from 1 January 2003 to 31 July 2005. Patients were eligible for the analysis if they had a diagnosis of hypertension, dyslipidaemia or diabetes mellitus, were written a prescription for standard fenofibrate 160 mg during the period 1 May 2004 to 30 April 2005, and were written a subsequent prescription for fenofibrate 145 mg NFE at least 60 days after first receiving the 160 mg dose. The outcomes measured were lipid levels: total-C, LDL-C, HDL-C and TG.

RESULTS

491 patients who switched from standard fenofibrate 160 mg to fenofibrate 145 mg NFE met all of the inclusion criteria. Patients who changed therapy to fenofibrate 145 mg NFE from standard fenofibrate 160 mg showed a beneficial response in lipid levels. Statistically significant patient-specific changes in lipid levels were observed for the change from baseline to standard fenofibrate 160 mg for three lipid levels (total-C, HDL-C and TG). Statistically significant changes were observed for the switch to fenofibrate 145 mg NFE for three lipid levels (total-C, LDL-C and TG).

CONCLUSIONS

More patients treated in an outpatient clinical practice had better lipid results when prescribed fenofibrate 145 mg NFE than those prescribed standard fenofibrate 160 mg, suggesting that a less restrictive dosing regimen improves lipid outcomes.

Expert perspective: reducing cardiovascular risk in metabolic syndrome and type 2 diabetes mellitus beyond low-density lipoprotein cholesterol lowering

Even with optimal statin therapy, many patients with type 2 diabetes mellitus or metabolic syndrome fail to achieve all lipid targets and remain at high risk of cardiovascular events. Add-on lipid-modifying therapy that is effective in improving the triglyceride and high-density lipoprotein (HDL) cholesterol abnormalities characteristic of these conditions is a recommended approach to reduce this risk. Fibrates or niacin is a logical option, supported by clinical studies showing improved lipid control in combination with a statin. Of the fibrates, fenofibrate may offer microvascular benefits in type 2 diabetes--as demonstrated by the Diabetes Atherosclerosis Intervention Study (DAIS) and the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study--as well as a low risk of myopathy when combined with statins compared with gemfibrozil. Although there is good evidence that both agents favorably affect clinical outcome, we need to evaluate their impact against a baseline of statin therapy. We await data from ongoing large-scale studies to evaluate the efficacy and safety of these combinations and to determine the most appropriate option for reducing residual cardiovascular risk in this important patient population.

Comparison of the effects of maximal dose atorvastatin and rosuvastatin therapy on cholesterol synthesis and absorption markers

We measured plasma markers of cholesterol synthesis (lathosterol) and absorption (campesterol, sitosterol, and cholestanol) in order to compare the effects of maximal doses of rosuvastatin with atorvastatin and investigate the basis for the significant individual variation in lipid lowering response to statin therapy. Measurements were performed in participants (n = 135) at baseline and after 6 weeks on either rosuvastatin (40 mg/day) or atorvastatin (80 mg/day) therapy. Plasma sterols were measured using gas-liquid chromatography. Rosuvastatin and atorvastatin significantly (P < 0.001) altered plasma total cholesterol (C) levels by -40%, and the ratios of lathosterol/C by -64% and -68%, and campesterol/C by +52% and +72%, respectively, with significant differences (P < 0.001) between the treatment groups for the latter parameter. When using absolute values of these markers, subjects with the greatest reductions in both synthesis (lathosterol) and absorption (campesterol) had significantly greater reductions in total C than subjects in whom the converse was true (-46% versus -34%, P = 0.001), with similar effects for LDL-C. Rosuvastatin and atorvastatin decreased markers of cholesterol synthesis and increased markers of fractional cholesterol absorption, with rosuvastatin having significantly less effect on the latter parameter than atorvastatin. In addition, alterations in absolute values of plasma sterols correlated with the cholesterol lowering response.

Effects of intensive atorvastatin and rosuvastatin treatment on apolipoprotein B-48 and remnant lipoprotein cholesterol levels

Atorvastatin and rosuvastatin at maximal doses are both highly effective in lowering low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) levels. Rosuvastatin has been shown to be more effective than atorvastatin in lowering LDL-C, small dense LDL-C and in raising high-density lipoprotein (HDL) and its subclasses. Intestinal lipoproteins containing apolipoprotein (apo) B-48 are also thought to be atherogenic particles. Our purpose in this study was to compare the effects of daily oral doses of atorvastatin 80 mg/day and rosuvastatin 40 mg/day over a 6-week period on serum apo B-48 (a marker of intestinal lipoproteins) and remnant lipoprotein cholesterol (RemL-C) levels (a marker of partially metabolized lipoproteins of both intestinal and liver origin), using novel direct assays in 270 hyperlipidemic men and women. Both atorvastatin and rosuvastatin caused significant (p<0.0001) and similar median decreases in TG (-33.0%, -27.6%), RemL-C (-58.7%, -61.5%), and apoB-48 (-37.5%, -32.1%) as compared to baseline. Our findings utilizing a specific immunoassay and a fairly large number of subjects extend prior studies indicating that statins significantly lower apolipoprotein B containing lipoproteins of both intestinal and liver origin.

Femtonewton force sensing with optically trapped nanotubes

We extract the distribution of both center-of-mass and angular fluctuations from three-dimensional tracking of optically trapped nanotubes. We measure the optical force and torque constants from autocorrelation and cross-correlation of the tracking signals. This allows us to isolate the angular Brownian motion. We demonstrate that nanotubes enable nanometer spatial and femtonewton force resolution in photonic force microscopy, the smallest to date. This has wide implications in nanotechnology, biotechnology, nanofluidics, and material science.

Review of the evidence for the clinical utility of lipoprotein-associated phospholipase A2 as a cardiovascular risk marker

A substantial body of peer-reviewed studies has been published validating the role of inflammation in atherogenesis and supporting lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) as a cardiovascular risk marker independent of and additive to traditional risk factors. As with elevated high-sensitivity C-reactive protein, an elevated Lp-PLA(2) level approximately doubles the risk for primary and secondary cardiovascular events. Interestingly, when both inflammatory markers are increased together, they provide an even greater predictive capability to help identify very-high-risk individuals who would benefit most from aggressive lipid-lowering therapy. High levels of Lp-PLA(2) are present in inflamed, rupture-prone plaques, and it appears that Lp-PLA(2) is released from these plaques into the circulation. Over 25 prospective epidemiologic studies have demonstrated the association of elevated Lp-PLA(2) levels with future coronary events and stroke-11 of 12 prospective studies have shown a statistically significant association between elevated Lp-PLA(2) and primary coronary or cardiovascular events, 12 of 13 have shown a statistically significant association with recurrent coronary or cardiovascular events, and 6 studies have shown a positive association with stroke. Lp-PLA(2) should be viewed today as an important cardiovascular risk marker whose utility is as an adjunct to the major risk factors to adjust absolute risk status and thereby modify low-density lipoprotein cholesterol goals. The low biologic fluctuation and high vascular specificity of Lp-PLA(2) makes it possible to use a single measurement in clinical decision making, and it also permits clinicians to follow the Lp-PLA(2) marker serially. Ultimately, Lp-PLA(2) may also be classified as a risk factor, but this should not detract from its utility today as a risk marker.

Consensus panel recommendation for incorporating lipoprotein-associated phospholipase A2 testing into cardiovascular disease risk assessment guidelines

A consensus panel was formed to review the rapidly emerging literature on the vascular-specific inflammatory marker lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) and to update recommendations for the appropriate use of this novel biomarker in clinical practice. The recommendations of the panel build on guidelines of the Adult Treatment Panel III (ATP III) and the American Heart Association/Centers for Disease Control (AHA/CDC) for cardiovascular risk assessment. Consistent with the ATP III guideline recommendations for the use of inflammatory markers, Lp-PLA(2) is recommended as an adjunct to traditional risk assessment in patients at moderate and high 10-year risk. A simplified framework for traditional Framingham risk factor assessment is proposed. As a highly specific biomarker for vascular inflammation, elevated Lp-PLA(2) levels should prompt consideration of increasing the cardiovascular risk category from moderate to high or high to very high risk, respectively. Because intensification of lifestyle changes and low-density lipoprotein (LDL) cholesterol lowering is beneficial in high-risk patients, regardless of baseline LDL cholesterol levels, consideration should be given to lowering the LDL cholesterol target by 30 mg/dL (1 mg/dL = 0.02586 mmol/L) in patients with high levels of Lp-PLA(2). Lp-PLA(2) is recommended as a diagnostic test for vascular inflammation to better identify patients at high or very high risk who will benefit from intensification of lipid-modifying therapies. However, at this time Lp-PLA(2) cannot be recommended as a target of therapy.

Effects of maximal doses of atorvastatin versus rosuvastatin on small dense low-density lipoprotein cholesterol levels

Maximal doses of atorvastatin and rosuvastatin are highly effective in lowering low-density lipoprotein (LDL) cholesterol and triglyceride levels; however, rosuvastatin has been shown to be significantly more effective than atorvastatin in lowering LDL cholesterol and in increasing high-density lipoprotein (HDL) and its subclasses. Our purpose in this post hoc subanalysis of an open-label study was to compare the effects of daily oral doses of rosuvastatin 40 mg with atorvastatin 80 mg over a 6-week period on direct LDL cholesterol and small dense LDL (sdLDL) cholesterol in 271 hyperlipidemic men and women versus baseline values. Rosuvastatin was significantly (p<0.01) more effective than atorvastatin in decreasing sdLDL cholesterol (-53% vs -46%), direct LDL cholesterol (-52% vs -50%), total cholesterol/HDL cholesterol ratio (-46% vs -39%), and non-HDL cholesterol (-51% vs -48%), The magnitude of these differences was modest, and the 2 statins caused similar decreases in triglyceride levels (-24% and -26%). In conclusion, our data indicate that the 2 statins, given at their maximal doses, significantly and beneficially alter the entire spectrum of lipoprotein particles, but that rosuvastatin is significantly more effective than atorvastatin in lowering direct LDL cholesterol and sdLDL cholesterol.