Effects of lipid lowering therapy on progression of coronary and carotid artery disease

Heparin-Free DALI LDL-Apheresis in Hyperlipidemic Patients: Efficacy, Safety and Biocompatibility

Background and Aim of Study

In routine DALI apheresis - the first technique for direct adsorption of lipoproteins from whole blood - heparin plus citrate (ACD-A) is used as anticoagulation regimen. However, recently several publications have warned of heparin-induced thrombocytopenia as a rare but potentially life-threatening complication of heparin administration (HIT type 2). The aim of the present study was therefore to test the efficacy and biocompatibility of DALI using a heparin-free anticoagulation regimen consisting exclusively of citrate.

Methods

Four symptomatic hypercholesterolemic patients on regular DALI apheresis were switched to the heparin-free protocol for two sessions each. Two of the patients were on oral anticoagulation using phenprocoumon. In the weekly sessions, 1.3 patient blood volumes were processed at a blood flow rate of 60 ml/min using ACD-A at a ratio of 1:20 (v/v) during adsorber priming and the session.

Results

Clinically, all sessions were essentially uneventful. Uncorrected lipoprotein reductions amounted to 65% for LDL-C, 62% for Lp(a), 53% for VLDL-C, 24% for HDL-C, 17% for triglycerides and 19% for fibrinogen. Cell counts remained virtually constant. No signs of hemolysis or clotting could be detected. Thromboplastin time (Quick) was slightly prolonged and partial thromboplastin time (PTT) moderately elevated in all patients. In constrast, whole blood coagulation time acc. to Lee-White and activated clotting times were increased only in orally anticoagulated patients. Biocompatibility in terms of complement, leukocyte and thrombocyte activation was excellent. Bradykinin activation was moderate peaking at 3038 pg/ml in the efferent line. Systemic thrombin-antithrombin complex (TAT) reflected perfect anticoagulation in orally anticoagulated patients and adequate anticoagulation in the patients without phenprocoumon.

Conclusion

In this pilot study, heparin-free DALI apheresis was safe and effective and may thus be performed in LDL-apheresis dependent patients who suffer from heparin intolerance.

Short-term atorvastatin therapy improves arterial stiffness of middle-aged systemic lupus erythematosus patients with pathological pulse wave velocity

Objectives Statins have been proposed as a potential treatment for systemic lupus erythematosus (SLE) due to their immunomodulatory properties, their role restoring endothelial function and preventing atherosclerosis. We evaluate the effect of a short period treatment with a low dose of atorvastatin and its withdrawal on early stage subclinical atherosclerosis. Methods Thirty-seven SLE females received 20 mg/day atorvastatin during eight weeks. At baseline, at the end of treatment and six months after atorvastatin withdrawal, disease activity, subclinical atherosclerosis -assessed by measuring carotid-femoral pulse wave velocity (PWV) - and quantification of circulating endothelial progenitor cells (EPC) - as a surrogate biological marker of subclinical atherosclerosis - were carried out. Results The group of SLE patients with baseline pathological arterial stiffness showed a significant decrease of PWV after atorvastatin therapy (8.43 ± 1.45 m/s vs 7.42 ± 1.06 m/s; p = 0.002) that is maintained six months after treatment finished. Only patients of the middle-aged group showed a nearly significant decrease in the PWV measured along the study (7.16 ± 1.23 m/s vs 6.76 ± 0.82 m/s; p = 0.05). Atorvastatin induced a significant decrease in the circulating EPC percentage (0.65 ± 0.67 vs 0.40 ± 0.31; p = 0.023) as well as a downward trend of disease activity that it is observed by a decrease in SLE disease activity index simultaneously with an increase in C3 complement and significant decrease in serum concentration of vascular endothelial grow factor (VEGF) and sVCAM-1. Conclusions Short-term atorvastatin therapy reduces arterial stiffness of SLE patients with baseline pathological PWV, who are mainly in the group of middle-aged patients. Further studies are needed to determine whether these patients would benefit from statin therapy in preventing cardiovascular events.

Effects of a healthy Nordic diet on cardiovascular risk factors in hypercholesterolaemic subjects: a randomized controlled trial (NORDIET)

OBJECTIVE

the aim of this study was to investigate the effects of a healthy Nordic diet (ND) on cardiovascular risk factors.

DESIGN AND SUBJECTS

in a randomized controlled trial (NORDIET) conducted in Sweden, 88 mildly hypercholesterolaemic subjects were randomly assigned to an ad libitum ND or control diet (subjects' usual Western diet) for 6 weeks. Participants in the ND group were provided with all meals and foods. Primary outcome measurements were low-density lipoprotein (LDL) cholesterol, and secondary outcomes were blood pressure (BP) and insulin sensitivity (fasting insulin and homeostatic model assessment-insulin resistance). The ND was rich in high-fibre plant foods, fruits, berries, vegetables, whole grains, rapeseed oil, nuts, fish and low-fat milk products, but low in salt, added sugars and saturated fats.

RESULTS

the ND contained 27%, 52%, 19% and 2% of energy from fat, carbohydrate, protein and alcohol, respectively. In total, 86 of 88 subjects randomly assigned to diet completed the study. Compared with controls, there was a decrease in plasma cholesterol (-16%, P < 0.001), LDL cholesterol (-21%, P < 0.001), high-density lipoprotein (HDL) cholesterol (-5%, P < 0.01), LDL/HDL (-14%, P < 0.01) and apolipoprotein (apo)B/apoA1 (-1%, P < 0.05) in the ND group. The ND reduced insulin (-9%, P = 0.01) and systolic BP by -6.6 ± 13.2 mmHg (-5%, P < 0.05) compared with the control diet. Despite the ad libitum nature of the ND, body weight decreased after 6 weeks in the ND compared with the control group (-4%, P < 0.001). After adjustment for weight change, the significant differences between groups remained for blood lipids, but not for insulin sensitivity or BP. There were no significant differences in diastolic BP or triglyceride or glucose concentrations.

CONCLUSIONS

a healthy ND improves blood lipid profile and insulin sensitivity and lowers blood pressure at clinically relevant levels in hypercholesterolaemic subjects.

Role of colesevelam in managing heterozygous familial hypercholesterolemia in adolescents and children

BACKGROUND

Colesevelam hydrochloride is a synthetic, nonsystemically absorbed polymer that functions as a bile acid sequestrant for the treatment of hypercholesterolemia. Recently, colesevelam was investigated for the treatment of heterozygous familial hypercholesterolemia (HeFH) in the pediatric/adolescent population aged 10-17 years.

OBJECTIVE

The purpose of this article is to review the disease state of HeFH in children and adolescents, review the pharmacologic mechanism of action, kinetics, and safety profile of colesevelam, analyze the results of a recent clinical trial of colesevelam in the pediatric/adolescent HeFH population, and discuss the role of colesevelam as a viable treatment option for HeFH.

METHODS

A literature search using Medline (1966-03 May 2010), PubMed (1950-03 May 2010), Science Direct (1994-03 May 2010), and International Pharmaceutical Abstracts (2004-2010) was performed using the search term colesevelam. English language, original research, and review articles were examined, and citations from these articles were also assessed. The manufacturer's prescribing information and the Food and Drug Administration review of the new drug application for the powder formulation were also examined.

RESULTS

A 32-week trial was performed investigating the efficacy of colesevelam as monotherapy or combination therapy with a stable statin regimen. Upon completion of the trial, significant benefits were found in regard to the treatment of HeFH and the lowering of low-density lipoprotein cholesterol, total cholesterol, and other secondary measures. Safety and tolerability were also examined throughout the duration of the clinical trial, with adverse drug reactions considered mild in severity.

CONCLUSION

Colesevelam has been shown to reduce low-density lipoprotein cholesterol levels significantly in pediatric/adolescent patients with HeFH, while maintaining a mild side effect profile. Although further research would be beneficial for long-term effects in this population, colesevelam should be considered when developing a treatment regimen for HeFH in the pediatric/adolescent population.

Myriocin-mediated up-regulation of hepatocyte apoA-I synthesis is associated with ERK inhibition

Sphingolipids including sphingomyelin have been implicated as potential atherogenic lipids. Studies in apoE (apolipoprotein E)-null mice have revealed that the serine palmitoyltransferase inhibitor myriocin reduces plasma levels of sphingomyelin, ceramide, sphingosine-1-phosphate and glycosphingolipids and that this is associated with potent inhibition of atherosclerosis. Interestingly, hepatic apoA-I (apolipoprotein A-I) synthesis and plasma HDL (high-density lipoprotein)-cholesterol levels were also increased in apoE-null mice treated with myriocin. Since myriocin is a known inhibitor of ERK (extracellular-signal-related kinase) phosphorylation, we assessed the possibility that myriocin may be acting to increase hepatic apoA-I production via this pathway. To address this, HepG2 cells and primary mouse hepatocytes were treated with 200 muM myriocin for up to 48 h. Myriocin increased apoA-I mRNA and protein levels by approx. 3- and 2-fold respectively. Myriocin also increased apoA-I secretion up to 3.5-fold and decreased ERK phosphorylation by approx. 70%. Similar findings were obtained when primary hepatocytes were isolated from apoE-null mice that were treated with myriocin (intraperitoneal injection at a dose of 0.3 mg/kg body weight). Further experiments revealed that the MEK (mitogen-activated protein kinase/ERK kinase) inhibitor PD98059 potently inhibited ERK phosphorylation, as expected, and increased primary hepatocyte apoA-I production by 3-fold. These results indicate that ERK phosphorylation plays a role in regulating hepatic apoA-I expression and suggest that the anti-atherogenic mechanism of action for myriocin may be linked to this pathway.

Effects on coronary atherosclerosis by targeting low-density lipoprotein cholesterol with statins

A correlation exists between circulating levels of low-density lipoprotein cholesterol (LDL-C) and risk of cardiovascular disease (CVD). Evidence from clinical trials indicates that reducing LDL-C levels can result in beneficial clinical outcomes in patients at risk of CVD and in high-risk patients with clinical symptoms of CVD. Lipid-lowering agents, of which HMG-CoA reductase inhibitors (statins) are the most effective, protect against the vascular changes seen in the development of atherosclerotic plaque formation. Clinical trials assessing the effects of statins on coronary atherosclerosis using quantitative coronary angiography or intravascular ultrasound showed that statins can reduce progression or even cause regression of atherosclerotic plaque. This improvement of vascular structure after statin treatment is correlated with reductions in LDL-C levels. This appears to be the principal mechanism by which statin therapy reduces cardiovascular risk, with emerging evidence for statin-mediated changes in high-density lipoprotein and C-reactive protein levels contributing to modification of the atherosclerotic plaque.

Three-Year Follow-up Results of Angiographic Intervention Trial Using an HMG-CoA Reductase Inhibitor to Evaluate Retardation of Obstructive Multiple Atheroma (ATHEROMA) Study

BACKGROUND

The cardiovascular event rate in Japanese populations is strikingly lower than that in Caucasian populations and it has been postulated that this difference might be because of variations in atherosclerosis progression in patients with coronary artery disease (CAD). However, the rate of angiographically assessed progression and its response to statins has not been well described in Japanese patients.

METHODS AND RESULTS

The angiographic intervention trial using an HMG-CoA reductase inhibitor to evaluate the retardation of obstructive multiple atheroma (ATHEROMA) study was a multicenter, randomized, controlled clinical trial investigating the effects of pravastatin on coronary atherosclerosis in Japanese patients with CAD using quantitative coronary angiography. In total, 361 patients with mild to moderate elevated serum total cholesterol concentrations (195-265 mg/dl) received diet only (n = 179) or diet plus pravastatin 10-20 mg/dl (n = 182). Over 3 years, low-density lipoprotein-cholesterol in the pravastatin group decreased by 19.5% (p < 0.0001). A per-patient analysis showed that minimum lumen diameter increased by 0.034+/-0.17 mm in the pravastatin group, but decreased by 0.006+/-0.16 mm in the diet only group (p = 0.04). The mean difference between the treatment groups was 0.040 mm (95% confidence interval 0.020, 0.070 mm).

CONCLUSION

The ATHEROMA study indicates that pravastatin 10-20 mg/day for 3 years improves hyperlipidemia, then suppresses progression and induces regression of focal coronary atherosclerosis in Japanese CAD patients with elevated serum cholesterol.

A randomized, open-label, comparative study of simvastatin plus diet versus diet alone on angiographic retardation of coronary atherosclerosis in adult Japanese patients: Japanese utilization of simvastatin therapy (JUST) study

BACKGROUND

Cholesterol-lowering therapy reduces the risk of cardiovascular events by slowing the progression or enhancing the regression of coronary atherosclerosis.

OBJECTIVE

This study assessed the effects of simvastatin 10 mg/d on progressive coronary atherosclerosis in Japanese patients with coronary artery disease and mild to moderate hypercholesterolemia.

METHODS

In a 2-year, open-label comparative study, patients with coronary atherosclerotic lesions (> or =50% diameter stenosis) and serum total cholesterol levels > or =200 and < or =280 mg/dL were randomly assigned to 2 groups: 1 group received simvastatin 10 mg/d taken orally with diet (S-D) and the other group was assigned to diet alone (D). Atherosclerotic progression in coronary segments was compared in the 2 groups using quantitative coronary angiography (QCA). QCA measurements were done under blinded conditions. The study's primary end point was the comparison of mean changes in each segment's minimum obstruction diameter (MOD) or mean segment diameter (MSD) between the S-D group and the D group.

RESULTS

A total of 299 patients were randomized, 146 to the S-D group and 153 to the D group. Mean (SD) age was 58.7 (8.0) years and mean (SD) total cholesterol level was 232.6 (21.6) mg/dL at baseline. After 2 years, serum low-density lipoprotein cholesterol levels decreased by 31.9% in the S-D group and by 2.0% in the D group. QCA showed significant stenotic progression in the D group, with reductions in MOD and MSD both by per-segment-based (P < 0.001 and P = 0.004, respectively) and per-patient-based (both P = 0.004) analyses. Although simvastatin treatment suppressed atherosclerotic progression in both per-segment- and per-patient-based analyses, significant reductions were found only in MOD values with per-segment-based analyses (P = 0.034). In a categorical approach, progression was found in significantly fewer segments in the S-D group compared with the D group (MOD, P = 0.014; MSD, P = 0.003), with odds ratios (S-D) group/D group) of 0.571 for MOD and 0.390 for MSD. Significantly fewer patients with angiographic progression were observed in the S-D group (23.3%) compared with the D group (39.4%) with respect to MSD (P = 0.02).

CONCLUSION

Two years of treatment with simvastatin 10 mg/d improved patients' lipid profile and retarded coronary atherosclerotic progression in Japanese patients with coronary artery disease and mild to moderate hypercholesterolemia

The cholesteryl ester transfer protein Taq1B gene polymorphism predicts clinical benefit of statin therapy in patients with significant coronary artery disease

BACKGROUND

Cholesteryl ester transfer protein (CETP) regulates plasma lipid distribution. A polymorphism in the CETP gene (Taq1B) is associated with CETP activity, HDL concentration, atherosclerosis progression, and response to statins, and may influence cardiovascular (CV) events. We studied CETP Taq1B genotype, plasma HDL, and clinical events among all patients and patients stratified by statin treatment.

METHODS

Consenting patients (n = 2531) with significant coronary artery disease (> or =1 lesion of > or =70% stenosis) undergoing coronary arteriography were genotyped, grouped by statin prescription at hospital discharge, and prospectively followed-up for the outcomes of all-cause mortality and myocardial infarction.

RESULTS

CETP Taq1B genotype frequencies were: B1B1, 32.9%; B1B2, 50.3%; and B2B2 16.8%. Plasma HDL was reduced for B1B1 patients (33 +/- 12 mg/dL, vs 36 +/- 13 mg/dL and 36 +/- 13 mg/dL for B1B2 and B2B2, respectively, P for trend =.003). Overall, event rates did not differ between genotypes. Event rates were similar among untreated (24.8%) and statin-treated (24.2%) B1 homozygotes (P = NS); statins significantly reduced events for B1B2 subjects (28.0% vs 21.0%, P =.009) and for B2B2 subjects (26.4% vs 17.4%, P =.048). Therapeutic benefit for B2 carriers remained after adjustment for covariates, and regression interaction analysis showed that B2 carriers experienced reduced events (relative risk [RR] 0.62, 95% CI 0.45-0.86), but statins did not benefit those with B1B1 (RR 1.09, 95% CI 0.70-1.7; P for interaction =.02). Findings were similar for the end point of death alone, although a modest benefit was seen in B1B1 patients (RR 0.67, P =.10), in addition to the strong benefit for B1B2 (RR 0.53, P =.001) and B2B2 (RR 0.28, P =.001).

CONCLUSIONS

The CETP Taq1B polymorphism is associated with differential HDL levels but no significant differential in CV risk in the absence of treatment. Importantly, however, CV event reduction by statin therapy is substantially enhanced in the presence of a B2 allele. Our findings suggest, for the first time, the potential of CETP Taq1B genotyping to enable more effective, pharmacogenetically directed therapy.

A decreased expression of angiopoietin-like 3 is protective against atherosclerosis in apoE-deficient mice

KK/Snk mice (previously KK/San) possessing a recessive mutation (hypl) of the angiopoietin-like 3 (Angptl3) gene homozygously exhibit a marked reduction of VLDL due to the decreased Angptl3 expression. Recently, we proposed that Angptl3 is a new class of lipid metabolism modulator regulating VLDL triglyceride (TG) levels through the inhibition of lipoprotein lipase (LPL) activity. In this study, to elucidate the role of Angptl3 in atherogenesis, we investigated the effects of hypl mutation against hyperlipidemia and atherosclerosis in apolipoprotein E knockout (apoEKO) mice. ApoEKO mice with hypl mutation (apoEKO-hypl) exhibited a significant reduction of VLDL TG, VLDL cholesterol, and plasma apoB levels compared with apoEKO mice. Hepatic VLDL TG secretion was comparable between both apoE-deficient mice. Turnover studies revealed that the clearance of both [3H]TG-labeled and 125I-labeled VLDL was significantly enhanced in apoEKO-hypl mice. Postprandial plasma TG levels also decreased in apoEKO-hypl mice. Both LPL and hepatic lipase activities in the postheparin plasma increased significantly in apoEKO-hypl mice, explaining the enhanced lipid metabolism. Furthermore, apoEKO-hypl mice developed 3-fold smaller atherogenic lesions in the aortic sinus compared with apoEKO mice. Taken together, the reduction of Angptl3 expression is protective against hyperlipidemia and atherosclerosis, even in the absence of apoE, owing to the enhanced catabolism and clearance of TG-rich lipoproteins.

Statins: mechanism of action and effects

The beneficial effects of statins are the result of their capacity to reduce cholesterol biosyntesis, mainly in the liver, where they are selectively distributed, as well as to the modulation of lipid metabolism, derived from their effect of inhibition upon HMG-CoA reductase. Statins have antiatherosclerotic effects, that positively correlate with the percent decrease in LDL cholesterol. In addition, they can exert antiatherosclerotic effects independently of their hypolipidemic action. Because the mevalonate metabolism generates a series of isoprenoids vital for different cellular functions, from cholesterol synthesis to the control of cell growth and differentiation, HMG-CoA reductase inhibition has beneficial pleiotropic effects. Consequently, statins reduce significantly the incidence of coronary events, both in primary and secondary prevention, being the most efficient hypolipidemic compounds that have reduced the rate of mortality in coronary patients. Independent of their hypolipidemic properties, statins interfere with events involved in bone formation and impede tumor cell growth.

Debate: "How low should LDL cholesterol be lowered?" Viewpoint: "It doesn't need to be very low"

The importance of low-density lipoprotein (LDL) control in the management of patients at high risk of cardiovascular events is unquestionable. The major statin trials have shown that the benefits of LDL lowering extend throughout the range of risk and the range of serum cholesterol, and have indicated that the protective effects of the intervention are mostly related to the baseline risk. Statin therapy is, for this reason, currently seen as an anti-atherogenic approach for the majority of high risk individuals and possibly all coronary heart disease patients. This debate is not about the value of statin therapy or the importance of LDL reduction, but about the goals to be set once we decide that LDL cholesterol must be reduced. With the National Cholesterol Education Program (NCEP) guidelines representing a solid middle ground, the two viewpoints in this debate try to argue, on one hand, that the LDL goals should be substantially lower than our current standards or, on the other, that a specific on-treatment LDL value may not be the most important goal to pursue. We defend the latter position by presenting the case that the most effective LDL intervention in high risk patients is to achieve a reduction of at least 30%. This strategy complies with the NCEP guidelines, as most of the high risk patients treated with an average dose of an average statin would experience a 30-40% LDL reduction that would put on-treatment LDL levels safely below goal. Our position differs from both the guidelines and the proponents of more aggressive LDL goals in the management of the two extremes of the cholesterol distribution, where our lack of interest in a predefined on-treatment LDL concentration would make us more aggressive than guidelines on low baseline LDL patients and less aggressive than guidelines on high baseline LDL patients.

Functional gamma-secretase inhibitors reduce beta-amyloid peptide levels in brain

Converging lines of evidence implicate the beta-amyloid peptide (Ass) as causative in Alzheimer's disease. We describe a novel class of compounds that reduce A beta production by functionally inhibiting gamma-secretase, the activity responsible for the carboxy-terminal cleavage required for A beta production. These molecules are active in both 293 HEK cells and neuronal cultures, and exert their effect upon A beta production without affecting protein secretion, most notably in the secreted forms of the amyloid precursor protein (APP). Oral administration of one of these compounds, N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester, to mice transgenic for human APP(V717F) reduces brain levels of Ass in a dose-dependent manner within 3 h. These studies represent the first demonstration of a reduction of brain A beta in vivo. Development of such novel functional gamma-secretase inhibitors will enable a clinical examination of the A beta hypothesis that Ass peptide drives the neuropathology observed in Alzheimer's disease.

The aggressive low density lipoprotein lowering controversy

Recent clinical trials have provided unequivocal evidence of major cardiovascular benefits from low density lipoprotein (LDL) lowering with statins. However, the three critical unresolved questions about aggressive LDL lowering are the shape of the curve relating cardiac events to LDL, the best surrogate measurement for assessing therapeutic efficacy and the best target for LDL therapy. The relation between cardiac events and LDL is curvilinear, both epidemiologically and during therapy. The benefit of lipid lowering diminishes progressively and becomes difficult to detect at lower LDL levels without a very large sample size. Assessment of the benefits of lipid lowering is further confounded by differences in the level of pretreatment LDL and by the non-LDL lowering effects of statins. Both epidemiologic studies and large randomized clinical trials have produced conflicting results concerning the best LDL target. Failure to reduce the event rate in patients with pretreatment LDL <125 mg (Cholesterol And Recurrent Events [CARE] trial) alerts us to the risk of extrapolating epidemiologic data to clinical practice, yet subset analysis of some clinical trials suggests the greatest benefit appears in those patients with the lowest on-treatment LDL levels (Scandinavian Simvastatin Survival Study [4S]). This controversy should be resolved in the next few years by several important on-going trials. In the face of seemingly contradictory data from current clinical trials, we can only speculate that very aggressive LDL lowering to <80 mg/dl could be accompanied by a modest therapeutic benefit beyond the current recommendations of the National Cholesterol Education Program. If any benefit is observed, it will have to be balanced against a small potential for increased adverse events.

Treating to target with statins

Large-scale drug intervention trials have proven that cholesterol-lowering therapy reduces the risk of coronary events in a wide range of at-risk patient groups. This has led to a growing consensus that plasma total and low-density lipoprotein cholesterol (LDL-C) should be reduced to target levels that have been shown in population studies to be associated with low rates of coronary heart disease (CHD). Despite this consensus, however, a substantial proportion of patients at high coronary risk still do not receive lipid-lowering therapy. Furthermore, of those patients receiving therapy, many do not achieve the recommended targets. In order to address this problem, several treatment-to-target studies have been conducted to determine whether recommended targets are attainable with the lipid-lowering drugs that are currently available. These studies have confirmed that the statins are able to achieve recommended target levels in the majority of patients at risk. The studies have also demonstrated that most patients achieve a total cholesterol target with atorvastatin.

Preventing, stopping, or reversing coronary artery disease--triglyceride-rich lipoproteins and associated lipoprotein and metabolic abnormalities: the need for recognition and treatment

A substantial number of treated patients with or at high risk for coronary artery disease continue to have fatal and nonfatal coronary artery events in spite of significant reduction of elevated levels of low-density lipoprotein cholesterol. Other lipoprotein abnormalities besides an elevated level of low-density lipoprotein cholesterol contribute to risk of coronary artery disease and coronary artery events, and the predominant abnormalities that appear to explain much of this continued risk are an elevated serum triglyceride level and a low level of high-density lipoprotein cholesterol. Most patients with coronary artery disease have a mixed dyslipidemia with hypertriglyceridemia, which is associated and metabolically intertwined with other atherogenic risk factors, including the presence of triglyceride-rich lipoprotein remnants, low levels of high-density lipoprotein cholesterol, small, dense, low-density lipoprotein particles, postprandial hyperlipidemia, and a prothrombotic state. Aggressive treatment of these patients needs to focus on these other lipoprotein abnormalities as much as on low-density lipoprotein cholesterol. Combination drug therapy will usually be required. Reliable assessment of risk of coronary artery disease from lipoprotein measurements and response to therapy requires inclusion of all atherogenic lipoproteins in laboratory measurements and treatment protocols. At present this may be best accomplished by use of non-high-density lipoprotein cholesterol (total cholesterol minus high-density lipoprotein cholesterol) calculated from standard laboratory lipoprotein values. Ultimately, a more comprehensive assessment of coronary artery disease risk and appropriate therapy may include measurement of lipoprotein subclass distribution including determination of low-density lipoprotein particle concentration and sizes of the various lipoprotein particles.

Complete atherosclerosis regression after human ApoE gene transfer in ApoE-deficient/nude mice

The apolipoprotein E (apoE)-deficient mouse is a relevant animal model of human atherosclerosis. Although the prevention of atherosclerosis development has been documented after somatic gene transfer into animal models, regression of lesions remains to be demonstrated. Thus, we used this genetically defined mouse model nn the nude background to show atherosclerosis regression. ApoE-deficient nude mice were infected with 5 x 10(8) or 10(9) plaque-forming units of a first-generation adenovirus encoding human apoE cDNA. The secretion of human apoE resulted in a rapid decrease of total cholesterol, which normalized the hypercholesterolemic phenotype within 14 days (from 600+/-100 to <100 microg/mL). Transgene expression was observed during a period of >4 months, with a normalization of cholesterol and triglyceride levels during 5 months. At that time, we successfully reinjected the recombinant adenovirus and observed the appearance of the human protein as well as the correction of lipoprotein phenotype. In mice killed 6 months-after the first infection, we observed a dose-dependent regression of fatty streak lesions in the aorta. We showed sustained expression of a transgene with a first-generation adenoviral vector and a correction of dyslipoproteinemia phenotype leading to lesion regression. These data demonstrate that somatic gene transfer can induce plaque regression.

DALI apheresis in hyperlipidemic patients: biocompatibility, efficacy, and selectivity of direct adsorption of lipoproteins from whole blood

Recently, the first apheresis technique for direct adsorption of low-density lipoprotein (LDL) and lipoprotein(a) [Lp(a)] from whole blood (DALI) was developed that does not require a prior plasma separation. That markedly simplifies the extracorporeal circuit. The aim of the present study was to test the acute biocompatibility, efficacy, and selectivity of DALI apheresis. In a prospective clinical study, 6 hypercholesterolemic patients suffering from angiographically proven atherosclerosis were treated 4 times each by DALI. 1.3 patient blood volumes were treated per session at blood flow rates of 60-80 ml/min using 750 or 1,000 ml of polyacrylate/polyacrylamide adsorber gel. The anticoagulation consisted of an initial heparin bolus followed by a citrate infusion. The sessions were clinically essentially uneventful. Mean corrected reductions of lipoproteins amounted to 65% for LDL-cholesterol, 54% for Lp(a), 28% for triglycerides, 1% for HDL-cholesterol, and 8% for fibrinogen. The selectivity of lipoprotein removal was high. Cell counts remained virtually unchanged and no signs of hemolysis or clotting were detected. Cell activation parameters elastase, beta-thromboglobulin, interleukin-1beta, and IL-6 showed no significant increase. Complement activation was negligible. There was significant, but clinically asymptomatic, bradykinin activation in the adsorber with mean maxima of 12,000 pg/ml in the efferent line at 1,000 ml of treated blood volume. In conclusion, DALI proved to be safe, selective, and efficient for the adsorption of LDL-C and Lp(a), which simplifies substantially the extracorporeal therapy in hypercholesterolemic patients.

Current perspectives on statins

Statins (HMG-CoA reductase inhibitors) are used widely for the treatment of hypercholesterolemia. They inhibit HMG-CoA reductase competitively, reduce LDL levels more than other cholesterol-lowering drugs, and lower triglyceride levels in hypertriglyceridemic patients. Statins are well tolerated and have an excellent safety record. Clinical trials in patients with and without coronary heart disease and with and without high cholesterol have demonstrated consistently that statins reduce the relative risk of major coronary events by approximately 30% and produce a greater absolute benefit in patients with higher baseline risk. Proposed mechanisms include favorable effects on plasma lipoproteins, endothelial function, plaque architecture and stability, thrombosis, and inflammation. Mechanisms independent of LDL lowering may play an important role in the clinical benefits conferred by these drugs and may ultimately broaden their indication from lipid-lowering to antiatherogenic agents.

Role of lipid-lowering pharmacotherapy in children

For patients with coronary artery disease and healthy middle-aged or older individuals with elevated cholesterol levels, treatment with cholesterol-lowering drugs reduces morbidity and sometimes mortality. Treatment reverses established atherosclerotic lesions within a relatively short period of time, suggesting that starting cholesterol-lowering drugs in adulthood is adequate for most people at risk. Children with genetic lipid disorders, including familial hypercholesterolaemia and familial combined hyperlipidaemia, may be candidates for earlier therapy. A complete assessment of risk factors should be undertaken to determine which children are at highest risk. Treatment should start with diet, because diet is an important independent protective factor for disease. The bile acid sequestrants (resins) are the only drugs approved for children and may reduce low density lipoprotein (LDL)-cholesterol levels by 15 to 20% at best. Long term tolerability is good, but many children will not take the resins because they find them unpalatable. Tablet formulations have higher acceptability. Some children require supplementation with fat soluble vitamins or folate. Although hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have not been tested in long term studies in children, safety records are excellent in adults. Short term studies show that HMG-CoA reductase inhibitors reduce LDL-cholesterol levels similarly in children and in adults. Thus, the drugs may be used in low dosages to treat some adolescents with exceptional risk of disease.

Mechanism of action of niacin on lipoprotein metabolism

It is generally accepted that the increased concentrations of apolipoprotein (apo) B containing very low-density lipoproteins (VLDL) and low-density lipoproteins (LDL), and decreased levels of apo AI containing high-density lipoproteins (HDL) are correlated to atherosclerotic cardiovascular disease. Current evidence indicates that the post-translational apo-B degradative processes regulate the hepatic assembly and secretion of VLDL and the subsequent generation of LDL particles. The availability of triglycerides (TG) for the addition to apo B during intracellular processing appears to play a central role in targeting apo B for either intracellular degradation or assembly and secretion as VLDL particles. Based on the availability of TG, the liver secretes either dense TG-poor VLDL2 or large TG-rich VLDL1 particles, and these particles serve as precursors for the formation of more buoyant or small, dense LDL particles by lipid transfer protein- and hepatic lipase-mediated processes. HDLs are a heterogenous class of lipoproteins, and apo AI (the major protein of HDL) participates in reverse cholesterol transport, a process by which excess cholesterol is eliminated. Recent studies indicate that HDL particles containing only apo A-I (LPA-I) are more effective in reverse cholesterol transport and more anti-atherogenic than HDL particles containing both apo A-I and apo A-II (LPA-I + A-II).

Low density lipoprotein hemoperfusion by direct adsorption of lipoproteins from whole blood (DALI apheresis): clinical experience from a single center

The elimination of low density lipoprotein (LDL) and lipoprotein (a) (Lp[a]) by conventional LDL apheresis techniques can only be achieved in a cell-free medium and thus requires the initial separation of plasma from the blood cells. The present paper describes the first LDL hemoperfusion system which is able to adsorb LDL and Lp(a) directly from whole blood. This simplifies the procedure substantially. The adsorber consists of polyacrylate ligands linked to a modified polyacrylamide matrix. These negatively charged polyacrylate ligands interact with the positively charged apoprotein B moiety of LDL and Lp(a), which results in selective adsorption of these lipoproteins onto the column. Three hypercholesterolemic patients suffering from overt atherosclerotic complications were treated weekly by direct adsorption of lipoproteins (DALI) (n = 20 sessions each). All patients were on the highest tolerated dose of cholesterol synthesis enzyme (CSE) inhibitors. About 1.3 patient blood volumes were treated per session. The anticoagulation was performed with acid citrate dextrose (ACD-A). The following acute reductions were achieved: LDL: 66%; Lp(a): 63%; and triglycerides: 29%. High density lipoprotein (HDL) (-13%) and fibrinogen (-16%) were not substantially reduced. The sessions were essentially uneventful. Due to a low ACD-A infusion rate, no hypocalcemic episodes were registered. One patient on enalapril was treated without complications when this angiotensin converting enzyme (ACE) inhibitor was withdrawn 2 days prior to apheresis. In summary, in our hands, DALI apheresis proved to be a simple, safe, and efficient method of lipid apheresis in hypercholesterolemic patients refractory to conservative lipid lowering therapy.

Lowering LDL cholesterol: questions from recent meta-analyses and subset analyses of clinical trial DataIssues from the Interdisciplinary Council on Reducing the Risk for Coronary Heart Disease, ninth Council meeting

The benefit of cholesterol-lowering therapy in the prevention of coronary heart disease (CHD) is well established. The secondary prevention Scandinavian Simvastatin Survival Study (4S) and the primary prevention West of Scotland Coronary Prevention Study (WOSCOPS) demonstrated that lipid lowering with a statin can dramatically and cost-effectively reduce CHD morbidity and mortality with no increase in noncardiovascular mortality. The Cholesterol and Recurrent Events (CARE) trial extended benefit to CHD patients without high cholesterol. Post hoc analyses of data from these large trials are contributing to speculation, driven by subset analyses and meta-analyses, about whether cholesterol intervention should be target based, as current guidelines recommend. Whereas CARE data support the importance of baseline LDL cholesterol (LDL-C), with greatest clinical event risk reduction in the upper part of the LDL-C range in the trial, 4S found no difference in outcome according to baseline LDL-C in a quartile analysis, and WOSCOPS found no linear relation between decrease in LDL-C and decrease in relative risk for CHD. Furthermore, WOSCOPS showed no additional clinical benefit with LDL-C lowering beyond approximately 24%. Questions raised by such analyses require answers from prospective, hypothesis-based data, and at present there is no compelling argument for moving away from LDL-C targets. The hypothesis-based findings of 4S, CARE, and WOSCOPS support current clinical guidelines, and lowering LDL-C may reduce risk more substantially than might have been predicted.

Low-density lipoproteins and risk for coronary artery disease

Based on the established relation between low-density lipoprotein (LDL) cholesterol and coronary artery disease (CAD), the treatment guidelines of the US National Cholesterol Education Program (NCEP) focus on LDL cholesterol reduction for primary and secondary prevention of CAD events. Abundant clinical trial evidence supports the importance of LDL cholesterol-lowering in decreasing CAD risk, both in angiographic trials, which measure CAD progression, and in trials with morbidity and mortality endpoints. The LDL cholesterol targets in the guidelines remain important treatment goals, and ongoing trials should answer questions of whether further reduction in LDL cholesterol will provide much additional benefit. Even in trials of statin therapy, in which substantial reductions of LDL cholesterol have been obtained, statins decrease (by 23-37%) but do not entirely eliminate events, suggesting that lipid parameters besides LDL cholesterol, such as high-density lipoprotein (HDL) cholesterol, triglyceride, lipoprotein(a), and LDL particle size and susceptibility to oxidation, as well as other risk factors, influence CAD risk. Unfortunately, at present, the majority of high-risk patients are not receiving either diet or drug therapy. Systematic screening to identify high-risk patients and methodical follow-up to implement diet, lifestyle modification, and drug therapy to lower LDL cholesterol, as provided for in the NCEP guidelines, should lead to significant benefits in the prevention of CAD events.

Clinical trial endpoints: angiograms, events, and plaque instability

Clinical trials provide evidence on methods for risk assessment of coronary artery disease and on interventions used to decrease risk. Plaque rupture, which leads to either progression of coronary artery disease or myocardial infarction, is the critical biologic event in the pathophysiology of atherothrombosis that leads to morbidity and mortality. Trials with endpoints of myocardial infarction and death provide direct information on the effect of intervention on morbidity and mortality, but these trials require extremely large sample sizes and long duration. To obtain clinical information more quickly and with fewer patients, investigators have conducted trials using surrogate endpoints that examine the effect of treatment on the underlying disease process through measures of atherosclerotic lesion progression and/or regression and new lesion development. Coronary angiography studies have consistently shown that lipid-modifying therapy decreases coronary artery disease progression. The correlation between rate of progression of coronary artery disease and clinical coronary events such as myocardial infarction and coronary death may be explained by the relation of both to the biologic process of plaque rupture and thrombosis.

Lipoprotein classes and coronary disease regression

Lowering LDL cholesterol (LDL-C) levels to reduce or prevent coronary artery disease (CAD) progression and cardiac events in hypercholesterolemic subjects is now widely accepted. The clinical benefit of lowering LDL-C has recently been extended to individuals with normal or mildly elevated LDL-C. Recent analyses of large primary and secondary CAD prevention trials, however, clearly demonstrated that reducing LDL-C levels does not entirely account for the coronary event reduction associated with lipid-lowering therapy. Growing and compelling evidence is emerging on the role of triglyceride-rich lipoproteins (VLDL and IDL), high density lipoproteins (HDL), and small, dense LDL, as well as non lipid risk factors, in the regression or stabilization of atherosclerotic plaques of mild/moderate severity, which are associated with clinical cardiac events. Enzymes involved in the tight metabolic interrelationship between triglyceride-rich lipoproteins, small, dense LDL and HDL levels may represent potential therapeutic targets for CAD prevention by favourably altering lipoprotein composition and physical properties in addition to the current therapeutic focus on lipoprotein levels.