Niacin: from mechanisms of action to therapeutic uses.

Niacin has broad spectrum lipid modifying and anti-atherosclerotic properties. It is the most effective medication available for raising raise high density lipoprotein (HDL) levels. Despite statin therapy there remains a considerable residual cardiovascular risk attributed to low HDL levels. Currently, statins decrease cardiovascular events and death by about 25-40%. Trials with surrogate endpoints have shown a decrease in endpoints by 60-90% when a combination of statin and niacin has been used. There is a growing interest in niacin in combination therapy to fill the treatment gap by modifying lipid parameters other than low density lipoprotein cholesterol. This review addresses the role of niacin in comprehensive lipid management with an emphasis on its mechanism of action, formulations, side effects, evidence from clinical trials and also focuses on practical issues related to niacin therapy.

Decreased skeletal muscle mitochondrial DNA in patients treated with high-dose simvastatin.

Statins are generally well tolerated, but can cause myopathy and have been associated with mitochondrial abnormalities. The aim of this study was to determine whether muscle mitochondrial DNA (mtDNA) levels are altered during statin therapy. We retrospectively quantified mtDNA in 86 skeletal muscle biopsy specimens collected as part of a previously published clinical trial of high-dose simvastatin or atorvastatin versus placebo.

Specificity of the commonly used enzymatic assay for plasma cholesterol determination.

AIM: To assess the specificity and sensitivity of the commonly used enzymatic colorimetric test for plasma cholesterol determination. METHODS: Interference with an enzymatic method for cholesterol measurement by several non-cholesterol sterols (beta sitosterol, campesterol, stigmasterol, stigmastanol, desmosterol, and lathosterol) was assessed. Some of these compounds are present in plasma at higher than normal concentrations either in rare genetic disorders, such as phytosterolaemia, or after the consumption of phytosterol enriched foods. RESULTS: The non-cholesterol sterols were detected by the assay in a linear manner. There was no competitive interference in the presence of cholesterol. CONCLUSIONS: This crossreactivity may affect the diagnosis and treatment of non-cholesterol dyslipidaemias, including phytosterolaemia and cerebrotendinous xanthomatosis. Similarly, changes in plasma lipid compositions after the consumption of phytosterol enriched foods cannot be specifically determined by this enzymatic assay. Until a more specific enzymatic assay is developed, alternative methods such as gas chromatography should be used to differentiate between cholesterol and non-cholesterol sterols.

Pathophysiology of apolipoprotein E deficiency in mice: relevance to apo E-related disorders in humans.

Apolipoprotein E (apo E) deficiency (or its abnormalities in humans) is associated with a series of pathological conditions including dyslipidemia, atherosclerosis, Alzheimer's disease, and shorter life span. The purpose of this study was to characterize these conditions in apo E-deficient C57BL/6J mice and relate them to human disorders. Deletion of apo E gene in mice is associated with changes in lipoprotein metabolism [plasma total cholesterol (TC) (>+400%), HDL cholesterol (-80%), HDL/TC, and HDL/LDL ratios (-93% and -96%, respectively), esterification rate in apo B-depleted plasma (+100%), plasma triglyceride (+200%), hepatic HMG-CoA reductase activity (-50%), hepatic cholesterol content (+30%)], decreased plasma homocyst(e)ine and glucose levels, and severe atherosclerosis and cutaneous xanthomatosis. Hepatic and lipoprotein lipase activities, hepatic LDL receptor function, and organ antioxidant capacity remain unchanged. Several histological/immunohistological stainings failed to detect potential markers for neurodegenerative disease in the brain of 37-wk-old male apo E-KO mice. Apo E-KO mice may have normal growth and development, but advanced atherosclerosis and xanthomatosis may indirectly reduce their life span. Apo E plays a crucial role in regulation of lipid metabolism and atherogenesis without affecting lipase activities, endogenous antioxidant capacity, or appearance of neurodegenerative markers in 37-wk-old male mice.

Lipoprotein lipase and apoE polymorphisms: relationship to hypertriglyceridemia during pregnancy.

Pregnancy is associated with increases in plasma total cholesterol (TC) and triglycerides (TG). Individuals with decreased LPL activity have a mild form of hypertriglyceridemia. Variations in the apolipoprotein E (apoE) gene have been associated with increases in plasma TG in addition to differences in plasma TC, LDL cholesterol (LDL-C), and HDL cholesterol (HDL-C). Because of the overproduction of TG-rich VLDL, normal pregnancy challenges the lipolytic capacity of LPL and the clearance of remnants particles. During pregnancy, LPL and apoE polymorphisms may contribute to hypertriglyceridemia. This study investigated the impact of three LPL polymorphisms and the apoE genotypes on lipid levels during pregnancy. Fasting plasma lipids were measured and analyses of the LPL and apoE polymorphisms were performed in 250 women in the third trimester of pregnancy. S447X carriers had lower TG (P = 0.003), and N291S carriers had lower HDL-C (P < 0.02) and higher fractional esterification rate of HDL (FER(HDL)) (P = 0.007), a measure of HDL particle size, than the noncarriers. The E2 allele was associated with lower TC, LDL-C, and FER(HDL) (P < 0.05) compared to the E3/E3 genotype. These findings support that LPL and apoE polymorphisms play an important role in lipid metabolism in pregnancy. The relationship of these polymorphisms to risk of coronary heart disease in women requires further study.

Advances in experimental dyslipidemia and atherosclerosis.

Among the models of dyslipidemia and atherosclerosis, a number of wild-type, naturally defective, and genetically modified animals (rabbits, mice, pigeons, dogs, pigs, and monkeys) have been characterized. In particular, their similarities to and differences from humans in respect to relevant biochemical, physiologic, and pathologic conditions have been evaluated. Features of atherosclerotic lesions and their specific relationship to plasma lipoprotein particles have been critically reviewed and summarized. All animal models studied have limitations: the most significant advantages and disadvantages of using a specific animal species are outlined here. New insights in lipid metabolism and genetic background with regard to variations in pathogenesis of dyslipidemia-associated atherogenesis have also been reviewed. Evidence suggests that among wild-type species, strains of White Carneau pigeons and Watanabe Heritable Hyperlipidemic and St. Thomas's Hospital rabbits are preferable to the cholesterol-fed wild-type animal species in dyslipidemia and atherosclerosis research. Evidence for the usefulness of both wild-type and transgenic animals in studying the involvement of inflammatory pathways and Chlamydia pneumoniae infection in pathogenesis of atherosclerosis has also been summarized. Transgenic mice and rabbits are excellent tools for studying specific gene-related disorders. However, despite these significant achievements in animal experimentation, there are no suitable animal models for several rare types of fatal dyslipidemia-associated disorders such as phytosterolemia and cerebrotendinous xanthomatosis. An excellent model of diabetic atherosclerosis is unavailable. The question of reversibility of atherosclerosis still remains unanswered. Further work is needed to overcome these deficiencies.

Hepatic cholesterol and bile acid synthesis, low-density lipoprotein receptor function, and plasma and fecal sterol levels in mice: effects of apolipoprotein E deficiency and probucol or phytosterol treatment.

We compared hepatic cholesterol metabolism in apolipoprotein (apo) E-knockout (KO) mice with their wild-type counterparts. We also investigated the effects of treatment with phytosterols or probucol on the activity of hepatic 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase (cholesterol synthesis), cholesterol 7 alpha-hydroxylase and sterol 27-hydroxylase (bile acid synthesis), and low-density lipoprotein (LDL) receptor function in this animal model of atherogenesis. These findings were then related to treatment-induced changes in plasma, hepatic, and fecal sterol concentrations. Mouse liver membranes have binding sites similar to LDL receptors; the receptor-mediated binding represents 80% of total binding and is LDL concentration-dependent. These binding sites have higher affinity for apo E-containing particles than apo B only-containing particles. Deletion of apo E gene was associated with several-fold increases in plasma cholesterol levels, 1.5-fold increase in hepatic cholesterol concentrations, 50% decrease in HMG-CoA reductase activity, 30% increase in cholesterol 7 alpha-hydroxylase and 25% decrease in LDL receptor function. Treatment of apo E-KO mice with either probucol or phytosterols significantly reduced plasma cholesterol levels. Phytosterols significantly increased the activity of hepatic HMG-CoA reductase, and probucol significantly increased cholesterol 7 alpha-hydroxylase activity. Neither treatment significantly altered hepatic LDL receptor function. Phytosterols, but not probucol, significantly increased fecal sterol excretion and decreased hepatic cholesterol concentrations. Plasma cholesterol lowering effects of phytosterols and probucol are due to different mechanisms: stimulation of cholesterol catabolism via increased bile acid synthesis by probucol and decreased cholesterol absorption by phytosterols. In the absence of apo E, hepatic LDL receptors could not be upregulated and did not contribute to the cholesterol lowering effects of either agent.

Common mutations in the lipoprotein lipase gene (LPL): effects on HDL-cholesterol levels in a Chinese Canadian population.

BACKGROUND: favorable lipid profiles including low total serum cholesterol (TC), TC/HDL-cholesterol (HDL-C) ratio and elevated HDL-C levels have been previously reported in Chinese living in China. More recent data, however, suggests a changing trend toward decreased HDL-C and increased TC and LDL cholesterol (LDL-C) in Chinese populations. Environmental factors likely contribute, in part, to these findings. However, genetic factors contributing to lipoprotein metabolism may also play a role in determining the lipid/lipoprotein phenotype observed in Chinese populations. Lipoprotein lipase (LPL) mutations have been associated with altered HDL-C concentrations in Caucasians but have not yet been studied in a large population of Chinese descent. METHODS: 1577 Chinese Canadians of Cantonese descent were recruited for a cardiovascular risk factor study. The frequency and effect of three LPL gene polymorphisms [Asp9Asn (D9N, n=374), Asn291Ser (N291S, n=321) and Ser447-Ter (S447X, n=403)] on serum HDL-C concentrations was assessed. All the three polymorphisms have been shown to alter HDL-C levels in different Caucasian populations. RESULTS: lower TC, LDL-C, and TG and higher HDL-C were observed in both male and female Chinese Canadian subjects compared to other population samples. The D9N and N291S LPL polymorphisms were identified in 1/374 (0.3%) and 5/321 (1.6%) subjects, respectively. Carrier frequency of the S447X mutation was (102/403) 25.3%. This S447X polymorphism was observed with higher frequency in males with HDL-C levels in the highest tertile compared with those in the lowest HDL-C tertile (carrier frequencies 37.3 vs. 19.4%) (P=0.046). CONCLUSION: in this cohort of Chinese Canadians, the serum lipid profiles were more favorable than what has been reported for Caucasian Canadians. A favorable spectrum of polymorphisms in the LPL gene may mitigate the adverse effects of western lifestyle on plasma lipoproteins in this cohort of Cantonese Canadians.

Surgical management of dyslipidemia: clinical and experimental evidence.

Coronary artery disease (CAD) is still a major cause of mortality in developed countries, and dyslipidemia is one of its major causes. In an attempt to reduce both mortality and morbidity from CAD, several dietary, pharmacological, and surgical approaches have been used to reduce plasma cholesterol levels. In this brief review, we summarize the evidence for cholesterol-lowering effects and safety of partial ileal bypass (PIB) procedure in both human and animal studies. The results of the Program on the Surgical Control of the Hyperlipidemias (POSCH), which involved a total of 838 subjects with myocardial infarction, are promising. A 5-year follow-up of this study revealed significant reductions of up to 27% in total cholesterol (TC) and up to 42% in low-density lipoprotein (LDL) cholesterol levels along with an increase of up to 8% in high-density lipoprotein (HDL) cholesterol levels as compared to controls. These changes were associated with other benefits such as increased HDL/TC and HDL/LDL ratios, and a significant decrease in apolipoprotein (apo) B100 and increase in apo AI levels. Similar results were also demonstrated by other studies. PIB surgery is one of the most effective methods for reduction of plasma cholesterol levels, particularly in patients with heterozygous familial hypercholesterolemia. This procedure is also applicable to treatment of sitosterolemia, a rare genetic disorder in which the absorption of plant sterols is abnormally high. Although no major complications of this method have been reported, more extensive studies are required to evaluate its long-term effects on renal and hepatic function. Similarly, long-term impact of this procedure on progression/regression of atherosclerotic lesions must be documented. Finally, indications for this procedure should be carefully considered, particularly in view of availability of other treatments of dyslipidemia.

Effective treatment of hyperhomocysteinemia in heart transplant recipients with and without renal failure.

BACKGROUND: Elevated total plasma homocysteine (tHcy) levels have been associated with vascular disease and higher mortality in patients with coronary artery disease. Graft coronary disease is a major cause of mortality in long-term survivors of heart transplantation, and hyperhomocysteinemia may be one of its causes. The objectives of our study were to establish the effectiveness of a 3 stage homocysteine-lowering algorithm in a group of 84 heart transplant (HTx) patients and to evaluate the effect of renal function on the response to homocysteine-lowering therapy. METHODS: Prospective treatment of 84 Htx patients (64 male; mean age, 48 +/- 13 years) with tHcy > 75th percentile consisted of a 3-stage treatment algorithm: Stage 1, folic acid (FA) 2 mg + vitamin (vit) B(12) 500 mcg daily; Stage 2, addition of vit B(6) 100 mg daily; Stage 3, increase FA to 15 mg daily. Serum creatinine (Cr) and tHcy levels were measured before treatment and 21 +/- 19 weeks after each stage of treatment. RESULTS: All 3 stages of treatment significantly lowered mean tHcy from 22.4 +/- 16.3 (mean +/- SD) micromol/liter to 16.3 +/- 6.7 micromol/liter (p < 0.00001), from 17.6 +/- 6.1 micromol/liter to 15.2 +/- 5.3 micromol/liter (p < 0.0001), and from 16.8 +/- 5.2 micromol/liter to 15.6 +/- 5.3 micromol/liter (p < 0.05), respectively. The average reduction from baseline was 38%. Creatinine levels did not change significantly during the study period. Total plasma homocysteine levels decreased below the 75th percentile in 55% of patients, with Cr levels significantly lower in this group of patients (126 +/- 36 micromol/liter vs 182 +/- 65 micromol/liter, p < 0.00001). However, we found no significant relationship between % change in tHcy and baseline Cr. CONCLUSIONS: In a group of 84 heart transplant patients with tHcy levels >75th percentile, treatment with FA and vit B(6) and B(12) according to a 3-stage algorithm resulted in statistically significant declines in mean tHcy levels. Overall, tHcy levels decreased 38%, with target tHcy levels <75th percentile achieved in 55% of the patients. The % change in tHcy was not related to Cr. Further studies are needed to correlate treatment of hyperhomocysteinemia with clinical endpoints, such as the time to development of transplant vasculopathy and long-term survival, and to define the most appropriate targets for therapy.

Risk factors for atherosclerosis in survivors of myocardial infarction and their spouses: comparison to controls without personal and family history of atherosclerosis.

To explore the hypothesis that an interplay between genetic and environmental factors contributes to the development of coronary atherosclerosis, we compared the prevalence of risk factors for atherosclerosis among survivors of myocardial infarction (MI) and their spouses and apparently healthy men and women (spousal pairs) with no personal and family history of atherosclerosis in three generations. There were no significant differences in life-style and dietary habits between the groups. The daily vegetable and/or fruit intake was generally low and did not differ between the groups. Thirty percent and 25% of men and women did not consume any vegetables or fruits, respectively. All differences found in the male MI survivors and control men were also found between the female groups: MI survivors and their spouses were significantly more obese and had higher systolic and diastolic blood pressure and more pathologic plasma lipid levels compared with control males and females, respectively. Compared with the control men and women, MI survivors and spouses had higher plasma homocysteine (Hcgamma) levels (15.3 +/- 10.5, 11.9 +/- 4.0, 16.9 +/- 5.5, and 14.3 +/- 4.0, micromol/L, respectively, P = .01). The frequency of the homozygous C677T 5,10-methylenetetrahydrofolate reductase (MTHFR) polymorphism in MI survivors was twice that observed in their spouses and controls (12.1%, 4.8%, and 5.8%, respectively), but this difference did not reach statistical significance. A statistically significant association of the MTHFR genotype and Hcgamma concentration (multiple ANOVA) was shown. Neither the frequencies of apolipoprotein E (apoE) alleles nor Asp9Asn mutation of exon 2, Asn29lSer mutation of exon 6, and Ser447Ter of exon 9 of the lipoprotein lipase (LPL) gene varied significantly among the groups. A possible explanation for our findings is that individuals with a genetic predisposition for atherosclerosis and their spouses share a life-style that results in a higher body mass index (BMI) and waist to hip ratio (WHR). On the other hand, individuals with no family history of atherosclerosis, despite an unhealthy life-style similar to that in the affected families (diet and physical activity), had a lower BMI and WHR and more favorable metabolic parameters, including plasma Hcgamma. In conclusion, we have shown that a personal and/or family history of atherosclerosis corresponds to the prevalence and level of risk factors for atherosclerosis. A combination of life-style factors and inherited metabolic abnormalities, including high plasma Hcgamma, are the more likely explanation for our findings.

Coronary artery disease in patients at low risk--apolipoprotein AI as an independent risk factor.

Many risk factors for coronary artery disease (CAD) have been established by large epidemiological studies. However, some patients without the major risk factors still develop disease. Preliminary analysis of individuals referred for angiography, who had no major risk factors associated with CAD, indicated that apolipoprotein-AI (apoAI) was significantly lower in patients with positive angiograms. The hypothesis that apoAI was an independent risk factor for CAD in low risk populations was put forth. One thousand and seventy-five consecutive patients underwent angiography, lipid analysis, and completed a risk factor questionnaire. Individuals with total cholesterol<5.2 mmol/l, high density lipoprotein (HDL)-cholesterol>0.9 mmol/l, systolic blood pressure<140 mmHg and diastolic blood pressure<90 mmHg, no diabetes, and no family history of premature CAD in first degree relatives were selected. Fifty-four patients met these selection criteria, 29 having positive evidence of CAD and 25 with no evidence of disease. Multivariate analysis revealed that, after adjusting for age and gender, serum apoAI level was the only variable predictive of CAD. This effect was independent of HDL cholesterol level and fractional esterification rate of HDL (FER(HDL)). These results point to an important role for apoAI in the atherogenic process, particularly in populations with no major CAD risk factors. Decreased levels of apoAI or LpAI may initiate atherosclerosis in a highly selected group of low risk patients.

Extensive lifestyle management intervention following cardiac rehabilitation: pilot study.

Long-term management of the lifestyles of cardiac patients who have completed a cardiac rehabilitation program (CRP), and the risks that may develop for future health problems, have not been extensively reported. The purpose of this pilot study of graduates of CRPs was to: (a) assess lifestyle and risk factor trends, (b) test certain protocols, and (c) identify the challenges and limitations in managing lifestyles and risk factors. A convenience sample of 49 people with ischemic heart disease (IHD) was randomized to a Lifestyle Management Intervention (LMI) group and a Usual Care (UC) group and followed for 6 months. Patients assigned to the LMI group underwent six additional exercise sessions and participated in telephone follow-ups and a counseling session. Patients in the UC group were assessed at baseline and at the end of 6 months. Of the original 49 participants, 17 in the LMI group and 19 in the UC group completed the study. Patients in the LMI group showed significant reductions in total cholesterol and LDL-C from baseline at 6 months. Diastolic blood pressure was decreased significantly in the UC group. The study identified the challenges of lifestyle intervention and found that favorable risk factor modifications are possible for patients who have completed a CRP.

Lipid screening to prevent coronary artery disease: a quantitative evaluation of evolving guidelines.

BACKGROUND: There is strong evidence to support the treatment of abnormal blood lipid levels among people with cardiovascular disease. Primary prevention is problematic because many individuals with lipid abnormalities may never actually develop cardiovascular disease. We evaluated the 1998 Canadian lipid guidelines to determine whether they accurately identify high-risk adults for primary prevention. METHODS: Using data from the Lipid Research Clinics and receiver operating characteristic (ROC) curves, we compared the diagnostic performance of the 1998 lipid guidelines when risk factors for coronary artery disease (CAD) were counted versus calculating risk using Framingham risk equations. We also compared the diagnostic accuracy of the 1998 guidelines with guidelines previously published by the National Cholesterol Education Program in the United States and the 1988 Canadian Consensus Conference on Cholesterol and then used Canadian Heart Health Survey data to forecast lipid screening and treatment rates for the Canadian population. RESULTS: The Framingham risk equations were more accurate than counting risk factors for predicting CAD risk (areas under the ROC curves, 0.83 [standard deviation (SD) 0.02] v. 0.77 [SD 0.03], p < 0.05). Risk counting was a particularly poor method for predicting risk for women. The 1998 Canadian guidelines identified high-risk individuals more accurately than the earlier guidelines, but the increased accuracy was largely due to a lower false-positive rate or a higher true-negative rate (i.e., increased test specificity). Using the 1998 lipid guidelines we estimate that 5.9 million Canadians currently free of cardiovascular disease would be eligible for lipid screening and 322,705 (5.5%) would require therapy. INTERPRETATION: Calculating risk using risk equations is a more accurate method to identify people at high risk for CAD than counting the number of risk factors present, especially for women, and the 1998 Canadian lipid screening guidelines are significantly better at identifying high-risk patients than the 1988 guidelines. Many of our findings were incorporated into the new 2000 guidelines.

Laboratory standardization of a large international clinical trial: the DAIS experience. DAIS Project Group. Diabetes Atherosclerosis Intervention Study.

OBJECTIVE: To implement a quality control program for the standardization and harmonization of lipid and lipoprotein analyses as performed at two core laboratories (St. Paul's Hospital, UBC [Vancouver], and NPHI [Helsinki]) for the Diabetes Atherosclerosis Intervention Study (DAIS). DESIGN AND METHODS: A DAISSOFT computer program was designed to minimize the occurrence of data and sample management errors during the course of the study. Fresh human serum was used for the provision of an accuracy based external quality control program that monitored the analytical performance of lipid testing at these two laboratories. A separate program was designed for monitoring hemoglobin A1c (HbA1c). At the outset of the study, allowable total error goals were established for each analyte. Ongoing performance was monitored using bimonthly blinded challenges of fresh human serum. The two EQA programs routinely monitored the analysis of total cholesterol, calculated LDL-cholesterol, HDL-cholesterol, net triglycerides, apoprotein A-1, apoprotein B, and HbA1c. RESULTS: The EQA precision and accuracy data for the measurement of total cholesterol at the two core laboratories over the last 5 years indicated both laboratories operated with good precision, approximately 1% CV over the time period. The accuracy at both laboratories was similar initially. Part way through the study, the accuracy of the cholesterol method at NHPI tended to drift upward with an operating positive bias (+3%) relative to the Abell Kendall reference method. Triglyceride measurements were the most problematic for the study. By EQA cycle 8, the accuracy of the method at UBC had stabilized and was meeting the accuracy goals of the study. NPHI's method was negatively biased relative to the accuracy base of the DAIS study. In spite of recalibrating their method, NPHI found it difficult to maintain consistent accuracy for the measurement of triglycerides during the study. Both laboratories operated their HDL methods with excellent precision. Accuracy at NHPI was well maintained over the course of the study whereas the accuracy of HDL measurements at UBC was more problematic. There was an inconsistent variation in the accuracy of apoprotein A-1 measurements at both laboratories. In most cases, the bias would be corrected by the time of the next EQA challenge. In the case of apo B, one laboratory was standardized to the CDC while the other laboratory was standardized to IFCC/WHO. The discrepancy between these two accuracy bases was >20%. Recalibration to a common accuracy base rectified the problem. Only minor problems were encountered with the precision and accuracy of the DIAMAT assay for hemoglobin A-1c. The two DAIS core laboratories consistently operated within the 9% total error goals of the study for HbA1c. CONCLUSIONS: Through the use of this program, the two DAIS core laboratories were able to maintain their lipid analyses within the limits of allowable total error that had been established for the study.

Pharmacotherapy of hypercholesterolaemia: statins in clinical practice.

The objective of this article is to evaluate the roles of the lipid-lowering class of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) in reducing cardiovascular events and to review their mechanism of action based on in vitro and in vivo studies. The clinical outcome of 15 major clinical trials has been critically reviewed and summarised; all showed a high degree of efficacy and safety. Statins, either in active or prodrug forms, are potent inhibitors of HMG-CoA reductase, have good absorption rate and their bioavailability depends on their lipophobicity and concomitant use with meals. Abdominal discomfort is the most commonly reported adverse effect. Although the incidence is low, myopathy with or without rhabdomyolysis may be considered a serious adverse effect of statins. A combination of a statin with gemfibrozil seems to increase the risk of this adverse event, particularly in patients with renal impairment. Combination therapy with several other agents, frequently administered to cardiovascular patients, has also been reviewed. Statin therapy is considered highly cost effective in secondary prevention, but it is less cost effective in primary prevention. This factor may underline the rationale for developing other safe and effective agents with an improved cost effectiveness profile. The pleiotropic non-lipid lowering effects of statins may include their anti-oxidant and antithrombotic potential as well as restoration of endothelial function. Statins may also be beneficial in the treatment of osteoporosis. Fewer studies have investigated statins' effects on the quality of lipoprotein particles, the activities of cholesteryl ester transfer protein and lecithin:cholesterol acyltransferase as well as their possible synergistic effects with n-3 fatty acids, anti-oxidants and aspirin in reducing cardiovascular events.

Advances in understanding of the role of lecithin cholesterol acyltransferase (LCAT) in cholesterol transport.

We review the structure and function of lecithin cholesterol acyl transferase (LCAT), the advances in the studies of molecular genetics of LCAT and its deficiency states as well as the developments in assessment of LCAT activity particularly the concept of measurement of fractional esterification rate of plasma cholesterol in the absence of apoB lipoproteins (FER(HDL)) as an indication of atherogenic risk. We discuss LCAT reaction from two points of view: one that is consistent with the general belief in LCAT antiatherogenic potential and another, namely, a proposed concept of potentially opposing roles of LCAT in normal and dyslipidemic plasmas. While other plasma lipoproteins can (in addition to HDL) provide unesterified cholesterol (UC) for LCAT reaction, HDL may play an unique role in trafficking of newly formed cholesteryl esters (CE) rather than as a primary acceptor of cellular cholesterol. Thus, the plasma HDL, specifically the larger (HDL2b) particles, direct the efflux of most of (LCAT produced) CE to its specific catabolic sites rather than to potentially atherogenic VLDLs and back to LDLs.