Lipoprotein profile in men with peripheral vascular disease. Role of intermediate density lipoproteins and apoprotein E phenotypes

Apolipoprotein E in Cardiometabolic and Neurological Health and Diseases

A preponderance of evidence obtained from genetically modified mice and human population studies reveals the association of apolipoprotein E (apoE) deficiency and polymorphisms with pathogenesis of numerous chronic diseases, including atherosclerosis, obesity/diabetes, and Alzheimer’s disease. The human APOE gene is polymorphic with three major alleles, ε2, ε3 and ε4, encoding apoE2, apoE3, and apoE4, respectively. The APOE gene is expressed in many cell types, including hepatocytes, adipocytes, immune cells of the myeloid lineage, vascular smooth muscle cells, and in the brain. ApoE is present in subclasses of plasma lipoproteins, and it mediates the clearance of atherogenic lipoproteins from plasma circulation via its interaction with LDL receptor family proteins and heparan sulfate proteoglycans. Extracellular apoE also interacts with cell surface receptors and confers signaling events for cell regulation, while apoE expressed endogenously in various cell types regulates cell functions via autocrine and paracrine mechanisms. This review article focuses on lipoprotein transport-dependent and -independent mechanisms by which apoE deficiency or polymorphisms contribute to cardiovascular disease, metabolic disease, and neurological disorders.

Undertreatment or Overtreatment With Statins: Where Are We?

Statins, in addition to healthy lifestyle interventions, are the cornerstone of lipid-lowering therapy. Other low-density lipoprotein (LDL)-lowering drugs include ezetimibe, bile acid sequestrants, and PCSK9 inhibitors. As new evidence emerges from new clinical trials, therapeutic goals change, leading to renewed clinical guidelines. Nowadays, LDL goals are getting lower, leading to the "lower is better" paradigm in LDL-cholesterol (LDL-C) management. Several observational studies have shown that LDL-C control in real life is suboptimal in both primary and secondary preventions. It is critical to enhance the adherence to guideline recommendations through shared decision-making between clinicians and patients, with patient engagement in selecting interventions based on individual values, preferences, and associated conditions and comorbidities. This narrative review summarizes the evidence regarding the benefits of lipid-lowering drugs in reducing cardiovascular events, the pleiotropic effect of statins, real-world data on overtreatment and undertreatment of lipid-lowering therapies, and the changing LDL-C in targets in the clinical guidelines of dyslipidemias over the years.

Distinct pro-inflammatory properties of myeloid cell-derived apolipoprotein E2 and E4 in atherosclerosis promotion

Polymorphisms in the apolipoprotein E (apoE) gene are risk factors for chronic inflammatory diseases including atherosclerosis. The gene product apoE is synthesized in many cell types and has both lipid transport–dependent and lipid transport–independent functions. Previous studies have shown that apoE expression in myeloid cells protects against atherogenesis in hypercholesterolemic ApoE^−/− mice. However, the mechanism of this protection is still unclear. Using human APOE gene replacement mice as models, this study showed that apoE2 and apoE4 expressed endogenously in myeloid cells enhanced the inflammatory response via mechanisms independent of plasma lipoprotein transport. The data revealed that apoE2-expressing myeloid cells contained higher intracellular cholesterol levels because of impaired efflux, causing increasing inflammasome activation and myelopoiesis. In contrast, intracellular cholesterol levels were not elevated in apoE4-expressing myeloid cells, and its proinflammatory property was found to be independent of inflammasome signaling and related to enhanced oxidative stress. When ApoE^−/− mice were reconstituted with bone marrow from various human APOE gene replacement mice, effective reduction of atherosclerosis was observed with marrow cells obtained from APOE3 but not APOE2 and APOE4 gene replacement mice. Taken together, these results documented that apoE2 and apoE4 expression in myeloid cells promotes inflammation via distinct mechanisms and promotes atherosclerosis in a plasma lipoprotein transport–independent manner.

Association of apolipoprotein levels with peripheral arterial disease: a meta-analysis of literature studies

AIMS

Lower limb peripheral artery disease (PAD) is a leading cause of atherosclerotic cardiovascular disease (ASCVD). Discordant data are available on the association between apolipoprotein and PAD. We performed a meta-analyses on the association between apolipoprotein (apo)B, apoA-I, and apoB/apoA-I ratio with PAD.

METHODS AND RESULTS

PubMed, Web of Science, Scopus databases were systematically searched. Studies providing data about apoB, apoA-I, apoB/apoA-I ratio in PAD subjects and non-PAD controls were included. Differences between PAD and non-PAD subjects were expressed as mean difference (MD) with pertinent 95% confidence intervals (95%CI). Twenty-two studies were included. Peripheral artery disease subjects showed higher apoB (MD: 12.5 mg/dL, 95%CI: 2.14, 22.87) and lower apoA-I levels (MD: -7.11 mg/dL, 95%CI: -11.94, -2.28) than non-PAD controls. Accordingly, ApoB/ApoA-I ratio resulted higher in PAD subjects than non-PAD controls (MD: 0.11, 95% CI: 0.00, 0.21). Non-HDL-C showed a direct association with the difference in apoB (z-value: 4.72, P < 0.001) and an inverse association with the difference of apoA-I (z-value: -2.43, P = 0.015) between PAD subjects and non-PAD controls. An increasing BMI was associated with an increasing difference in apoA-I values between PAD subjects and non-PAD controls (z-value: 1.98, P = 0.047).

CONCLUSIONS

Our meta-analysis suggests that PAD subjects exhibit increased apoB and reduced apoA-I levels, accompanied by an increased apoB/apoA-I ratio as compared with non-PAD controls.

The relation between VLDL-cholesterol and risk of cardiovascular events in patients with manifest cardiovascular disease

INTRODUCTION

Apolipoprotein B containing lipoproteins are atherogenic. There is evidence that with low plasma low density lipoprotein cholesterol (LDL-C) levels residual vascular risk might be caused by triglyceride rich lipoproteins such as very-low density lipoproteins (VLDL), chylomicrons and their remnants. We investigated the relationship between VLDL-cholesterol (VLDL-C) and recurrent major adverse cardiovascular events (MACE), major adverse limb events (MALE) and all-cause mortality in a cohort of patients with cardiovascular disease.

METHODS

Prospective cohort study in 8057 patients with cardiovascular disease from the UCC-SMART study. The relation between calculated VLDL-C levels and the occurrence of MACE, MALE and all-cause mortality was analyzed with Cox regression models.

RESULTS

Patients mean age was 60 ± 10 years, 74% were male, 4894 (61%) had coronary artery disease, 2445 (30%) stroke, 1425 (18%) peripheral arterial disease and 684 (8%) patients had an abdominal aorta aneurysm at baseline. A total of 1535 MACE, 571 MALE and 1792 deaths were observed during a median follow up of 8.2 years (interquartile range 4.512.2). VLDL-C was not associated with risk of MACE or all-cause mortality. In the highest quartile of VLDL-C the risk was higher for major adverse limb events (MALE) (HR 1.49; 95%CI 1.16-1.93) compared to the lowest quartile, after adjustment for confounders including LDL-C and lipid lowering medication.

CONCLUSION

In patients with clinically manifest cardiovascular disease plasma VLDL-C confers an increased risk for MALE, but not for MACE and all-cause mortality, independent of established risk factors including LDL-C and lipid-lowering medication.

Oxygen-Ozone (O2-O3) Therapy in Peripheral Arterial Disease (PAD): A Review Study

The purpose of this study is to review the current knowledge of oxygen-ozone (O₂-O₃) therapy and its effects on peripheral artery disease (PAD) risk factors, symptoms, as well as on PAD patients’ quality of life. From the in vitro studies, it has been concluded that the oxygen-ozone therapy exerts a positive effect on the platelet aggregation, cell remodeling, cytoskeletal elements organization and mitochondria structure. In animal studies, it has been shown that the O₂-O₃ therapy is an effective method in hypertension, and it diminishes the hypoxia state of various tissues. Clinical studies have provided evidence on the oxygen-ozone therapy effectiveness in low perfusion syndromes and hyperglycemia, as well as conditions with oxidative stress and inflammation. The oxygen-ozone therapy promotes faster recovery and enhances healing processes. It appears to be an effective adjunctive therapy in preventing peripheral artery disease complications such as occurrence of cardiovascular event, amputation or other extreme surgical solutions. It has been concluded that the O₂-O₃ therapy improves the quality of life of PAD patients. The oxygen-ozone therapy appears to have no adverse events or side effects. Moreover, it is very cost-effective, as standard treatment costs can be reduced by 25%. Easy clinical protocols allow the implementation of oxygen-ozone therapy into the usual care of PAD patients. Finally, the O₂-O₃ therapy may be meaningful especially for older patients and patients who are not eligible for standard revascularization.

MR-LDP: a two-sample Mendelian randomization for GWAS summary statistics accounting for linkage disequilibrium and horizontal pleiotropy

The proliferation of genome-wide association studies (GWAS) has prompted the use of two-sample Mendelian randomization (MR) with genetic variants as instrumental variables (IVs) for drawing reliable causal relationships between health risk factors and disease outcomes. However, the unique features of GWAS demand that MR methods account for both linkage disequilibrium (LD) and ubiquitously existing horizontal pleiotropy among complex traits, which is the phenomenon wherein a variant affects the outcome through mechanisms other than exclusively through the exposure. Therefore, statistical methods that fail to consider LD and horizontal pleiotropy can lead to biased estimates and false-positive causal relationships. To overcome these limitations, we proposed a probabilistic model for MR analysis in identifying the causal effects between risk factors and disease outcomes using GWAS summary statistics in the presence of LD and to properly account for horizontal pleiotropy among genetic variants (MR-LDP) and develop a computationally efficient algorithm to make the causal inference. We then conducted comprehensive simulation studies to demonstrate the advantages of MR-LDP over the existing methods. Moreover, we used two real exposure-outcome pairs to validate the results from MR-LDP compared with alternative methods, showing that our method is more efficient in using all-instrumental variants in LD. By further applying MR-LDP to lipid traits and body mass index (BMI) as risk factors for complex diseases, we identified multiple pairs of significant causal relationships, including a protective effect of high-density lipoprotein cholesterol on peripheral vascular disease and a positive causal effect of BMI on hemorrhoids.

Current concepts in curative surgery for diabetic forefoot ulcers

Forefoot ulcerations in patients with diabetes are quite common. Underlying mechanical deformities of the foot in combination with neuropathy are the most important risk factors for ulcer development and adequate offloading is the mainstay of management. Most ulcers heal with local wound care, adequate blood supply, and pressure relief. If a foot deformity cannot be accommodated, ulcers will not heal or may recur. In this case, surgical correction of deformity is necessary. This paper reviews the most common procedures supported by medical evidence to heal neuropathic forefoot ulcers.

The role of surgical off-loading to prevent recurrent ulcerations

Foot ulcerations in patients with diabetes are common. Most ulcers heal with conservative treatment, but recurrence is common. The pathway of ulcer development includes neuropathy, deformity, and trauma. The first attempt to avoid recurrence is by the use of shoes and insoles. When shoes and insoles fail, surgical correction of deformity leading to the ulcer can be attempted. This article reviews the most common procedures performed to heal ulcers or avoid recurrence.

Peripheral arterial disease, type 2 diabetes and postprandial lipidaemia: Is there a link?

Peripheral arterial disease, manifested as intermittent claudication or critical ischaemia, or identified by an ankle/brachial index < 0.9, is present in at least one in every four patients with type 2 diabetes mellitus. Several reasons exist for peripheral arterial disease in diabetes. In addition to hyperglycaemia, smoking and hypertension, the dyslipidaemia that accompanies type 2 diabetes and is characterised by increased triglyceride levels and reduced high-density lipoprotein cholesterol concentrations also seems to contribute to this association. Recent years have witnessed an increased interest in postprandial lipidaemia, as a result of various prospective studies showing that non-fasting triglycerides predict the onset of arteriosclerotic cardiovascular disease better than fasting measurements do. Additionally, the use of certain specific postprandial particle markers, such as apolipoprotein B-48, makes it easier and more simple to approach the postprandial phenomenon. Despite this, only a few studies have evaluated the role of postprandial triglycerides in the development of peripheral arterial disease and type 2 diabetes. The purpose of this review is to examine the epidemiology and risk factors of peripheral arterial disease in type 2 diabetes, focusing on the role of postprandial triglycerides and particles.

Dyslipidemia in obesity: mechanisms and potential targets

Obesity has become a major worldwide health problem. In every single country in the world, the incidence of obesity is rising continuously and therefore, the associated morbidity, mortality and both medical and economical costs are expected to increase as well. The majority of these complications are related to co-morbid conditions that include coronary artery disease, hypertension, type 2 diabetes mellitus, respiratory disorders and dyslipidemia. Obesity increases cardiovascular risk through risk factors such as increased fasting plasma triglycerides, high LDL cholesterol, low HDL cholesterol, elevated blood glucose and insulin levels and high blood pressure. Novel lipid dependent, metabolic risk factors associated to obesity are the presence of the small dense LDL phenotype, postprandial hyperlipidemia with accumulation of atherogenic remnants and hepatic overproduction of apoB containing lipoproteins. All these lipid abnormalities are typical features of the metabolic syndrome and may be associated to a pro-inflammatory gradient which in part may originate in the adipose tissue itself and directly affect the endothelium. An important link between obesity, the metabolic syndrome and dyslipidemia, seems to be the development of insulin resistance in peripheral tissues leading to an enhanced hepatic flux of fatty acids from dietary sources, intravascular lipolysis and from adipose tissue resistant to the antilipolytic effects of insulin. The current review will focus on these aspects of lipid metabolism in obesity and potential interventions to treat the obesity related dyslipidemia.

Apolipoprotein E2 accentuates postprandial inflammation and diet-induced obesity to promote hyperinsulinemia in mice

Genetic studies have revealed the association between the ε2 allele of the apolipoprotein E (apoE) gene and greater risk of metabolic diseases. This study compared C57BL/6 mice in which the endogenous mouse gene has been replaced by the human APOE2 or APOE3 gene (APOE2 and APOE3 mice) to identify the mechanism underlying the relationship between ε2 and obesity and diabetes. In comparison with APOE3 mice, the APOE2 mice had elevated fasting plasma lipid and insulin levels and displayed prolonged postprandial hyperlipidemia accompanied by increased granulocyte number and inflammation 2 h after being fed a lipid-rich meal. In comparison with APOE3 mice, the APOE2 mice also showed increased adiposity when maintained on a Western-type, high-fat, high-cholesterol diet. Adipose tissue dysfunction with increased macrophage infiltration, abundant crown-like structures, and inflammation were also observed in adipose tissues of APOE2 mice. The severe adipocyte dysfunction and tissue inflammation corresponded with the robust hyperinsulinemia observed in APOE2 mice after being fed the Western-type diet. Taken together, these data showed that impaired plasma clearance of apoE2-containing, triglyceride-rich lipoproteins promotes lipid redistribution to neutrophils and adipocytes to accentuate inflammation and adiposity, thereby accelerating the development of hyperinsulinemia that will ultimately lead to advanced metabolic diseases.

Impact of peripheral arterial disease on functional limitation in congestive heart failure: results from the national health and nutrition examination survey (1999-2004)

Background. Peripheral arterial disease (PAD) often coexists with congestive heart failure (CHF) and can be masked by symptoms of CHF such as functional limitation (FL), a common manifestation for both. Therefore, we sought to estimate the prevalence of PAD and its independent association with FL in CHF. Methods. We conducted a cross-sectional study on National Health and Nutrition Examination Survey (NHANES) data from 1999 to 2004 to quantify weighted prevalence of CHF and PAD. Study cohort consisted of 7513, with ankle brachial index (ABI) measurements at baseline. Independent association of PAD (ABI ≤ 0.9) with FL in CHF was determined with multivariate logistic regression (MVLR). Results. Overall weighted PAD prevalence was 5.2%. CHF was present in 305 participants, and the weighted prevalence of PAD in this subgroup was 19.2%. When compared, participants with CHF and PAD were more likely to be older (P < 0.001), hypertensive (P = 0.005) and hypercholesterolemic (P = 0.013) than participants with CHF alone. MVLR showed that PAD (adjusted OR = 5.15; 95% CI: 2.2, 12.05: P < 0.05) and arthritis (adjusted OR = 2.36; 95% CI: 1.10, 5.06: P < 0.05) were independently associated with FL in CHF. Conclusion. Independent association of PAD with FL suggests the need for reinforced screening for PAD in individuals with CHF.

Diagnosis and management of peripheral artery disease in women

Peripheral artery disease (PAD) is a significant cause of morbidity and mortality in the USA. Not only is it a major cause of functional impairment and limb loss, but it is also strongly associated with an increased risk of myocardial infarction, stroke, and death. Large population studies have demonstrated high rates of PAD in women, but this is not widely recognized by the public or by clinicians. One potential reason for this is that women with PAD are more likely than men to be asymptomatic or have atypical symptoms. In addition, women with PAD experience higher rates of functional decline and may have poorer outcomes after surgical treatment for PAD compared with men. Currently, it is not known if there are sex-specific differences in risk factors for the onset, progression, and surgical outcomes of PAD. This review will focus on the diagnosis and management of PAD in women and examine sex-specific differences in the prevalence, risk factors, presentation, and outcomes of this disease.

Homocysteine is a determinant of ApoA-I and both are associated with ankle brachial index, in an ambulatory elderly population

OBJECTIVE

The ankle brachial index (ABI) is an indicator of lower extremity peripheral arterial disease (PAD) and a predictor of atherothrombosis. ApoA-I and HDL are associated with PAD, in humans. Homocysteine influences the liver expression of ApoA-I and decreases its blood level and HDL in genetic mice models. We aimed therefore to evaluate whether homocysteine and its nutritional determinants, folate and vitamin B12 are associated with ABI by influencing HDL metabolism, in an ambulatory elderly population.

METHODS

667 elderly volunteers from rural Sicily were assessed for ABI, homocysteine and its determinants, lipid markers and other predictors of PAD. HDL size was assessed in 15 sera in upper and lower quartiles of Hcy distribution.

RESULTS

In multivariate analysis, ApoA-I and homocysteine were two predictors of ABI (β-coefficient = 2.86, P<0.004 and β-coefficient = -3.41, P<0.001, respectively). Homocysteine correlated negatively with ApoA-I (R = -0.147, P<0.001) and with HDL-Cholesterol (R = -0.113, P = 0.003). The associations of homocysteine, vitamin B12 and methylmalonic acid with ApoA-I and HDL2a particles and that of homocysteine with increased small size HDL3c suggested mechanisms related with impaired synthesis of ApoA-I and HDL and abnormal maturation of HDL particles.

CONCLUSION

The influence of homocysteine on ApoA-I and HDL metabolism provides new insights on its role on vascular diseases, at a cross-point between atherosclerosis and atherothrombosis.

Influencia de los factores genéticos y ambientales en el metabolismo lipídico y riesgo cardiovascular asociado al gen apoE

The apolipoprotein E (ApoE) plays an important role in lipid metabolism. This apoprotein presents three major isoforms (apoE2, apoE3 and apoE4) that modulate lipid levels. Carriers of the apoE4 allele have higher total and LDL-cholesterol plasma concentration and a greater coronary risk, particularly for myocardial infarction. Nevertheless, not all the people with this allele develop the disease, which suggests that other genetic or environmental factors are necessary for its total expression. In this review, we will analyze the importance of several polymorphisms in the apoE gene promoter region, as well as various environmental factors, including diet, in the association of this gene with lipid metabolism and cardiovascular risk.

Daily supplementation with (n-3) PUFAs, oleic acid, folic acid, and vitamins B-6 and E increases pain-free walking distance and improves risk factors in men with peripheral vascular disease

A number of nutrients are known to be effective in preventing cardiovascular disease (CVD). We investigated the possible effects of a daily intake of low amounts of these nutrients on risk factors and clinical parameters in patients with peripheral vascular disease and intermittent claudication (PVD-IC). Male PVD-IC patients (n = 60) were randomly allocated into 2 groups. The supplement (S) group consumed 500 mL/d of a fortified dairy product containing eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), oleic acid, folic acid, and vitamins A, B-6, D, and E. The control (C) group consumed 500 mL/d of semiskimmed milk with added vitamins A and D. The patients received lifestyle and dietary recommendations, and they were instructed to consume the products in addition to their regular diet. Blood extractions and clinical explorations were performed after 0, 3, 6, 9, and 12 mo. Plasma concentrations of EPA, DHA, oleic acid, folic acid, and vitamins B-6 and E increased after treatment with supplements (P < 0.05). Plasma total cholesterol and ApoB concentrations decreased in the S group, and total homocysteine decreased in those patients with high initial concentrations. Walking distance before the onset of claudication increased in the S group (P < 0.001), and ankle-brachial pressure index values increased (P < 0.05). The inclusion in the everyday diet of certain nutrients known to promote cardiovascular health improved clinical outcomes while reducing a variety of risk factors in men with PVD-IC, providing new evidence of the potential role of nutrition in the reduction of PVD-IC symptoms.

The S447X polymorphism of the lipoprotein lipase gene is associated with lipoprotein lipid and blood pressure levels in Chinese patients with essential hypertension

OBJECTIVE

To investigate the association between the S447X polymorphism of the lipoprotein lipase (LPL) gene and lipoprotein lipid and blood pressure (BP) levels in 904 Chinese subjects with essential hypertension.

METHOD

Five hundred and sixty-three male and 341 female patients (aged 35-69 years) were randomly selected from hypertensive patients diagnosed in the Community-based Comprehensive Studies on Prevention and Control of Hypertension Project in China (CCPACH) and not treated with antihypertensive medications for at least 2 weeks immediately before blood collection.

RESULTS

After multivariate adjustment for age, body mass index (BMI), smoking status, alcohol intake and serum glucose, the X447 allele was significantly associated with low triglyceride, log triglyceride : high-density lipoprotein (HDL)-cholesterol ratio and high HDL-cholesterol levels compared with the S447S genotype, but not with BP levels in the whole study population. However, upon stratification for dyslipidemic status, the X447 allele was associated with higher systolic blood pressure (SBP) (P < 0.05) and pulse pressure (PP) (P < 0.05) compared with the S447S genotype after multivariate adjustment in dyslipidemic subjects, but not in those without dyslipidemia. A statistically significant interaction between the LPL S447X polymorphism and dyslipidemic status was observed for SBP and PP levels, suggesting that dyslipidemic status might modify the effect of the LPL S447X polymorphism on BP levels.

CONCLUSIONS

Our findings suggest that a high concentration of triglyceride and/or low concentration of HDL-cholesterol are associated with high SBP and PP in hypertensive patients with the X447 allele of the LPL gene.

[Paraoxonase 1 gene 192 polymorphism, physical activity and lipoprotein in women]

BACKGROUND AND OBJECTIVE

Regular physical activity is associated with an increase in high-density lipoprotein cholesterol (HDL-C), whose antioxidant and protective effect for coronary artery disease is well known. Paraoxonase-1 (PON1) is an enzyme related with the antioxidant activity of HDL. The PON1 gene has several genetic polymorphisms; one of them locates in codon 192, whose alleles Q and R are associated with low and high PON1-activity, respectively. The objective of this study was to determine whether physical activity has different effects on the lipid profile in women depending on the PON1-192 genotype.

PATIENTS AND METHOD

Six hundred and fifty-one women from a cross-sectional risk-factor study were included in this retrospective cohort study. We analyzed anthropometrical characteristics, serum lipids and lipoproteins, blood pressure, PON1-192 genotypes and menopause. We used the Minnesota Leisure Time Physical Activity Questionnaire to assess the daily physical activity in the previous year.

RESULTS

Women included in the study were classified into three categories by tertiles of daily physical activity. Although no differences in the lipidic parameters were found, we observed an increasing trend in HDL-C concentration and a decreasing trend in log-triglyceride-to-HDL-cholesterol ratio with increasing physical activity in RR homozygous women. In subgroup analyses, we observed that the association of high physical activity and increased HDL-C concentration or decreased log-triglyceride-to-HDL-cholesterol ratio were exclusive for RR homozygous non-menopausal women.

CONCLUSIONS

The results of this study suggest that PON1-192 polymorphism could modulate the effect of physical activity on HDL-C concentration and on triglyceride-rich lipoprotein catabolism in non-menopausal women.

The case for early detection and integrated intervention in patients with peripheral arterial disease and intermittent claudication

Peripheral arterial disease (PAD) is defined as atherosclerotic disease of the aorta and arteries of the lower extremities. The most frequent manifestations of ischemia occur in the lower extremity arteries, with intermittent claudication as the most common symptom. Intermittent claudication, which is characterized by temporary pain brought on by muscle exertion, is usually experienced in the calf muscles and typically subsides with rest. The atherosclerotic nature of PAD/intermittent claudication makes it an important predictor of risk for cardio- and cerebrovascular disease, as well as limb loss. Thus, active screening and early diagnosis of PAD/intermittent claudication, in addition to aggressive management that incorporates risk factor modification, exercise therapy, platelet inhibition and other appropriate pharmacotherapy, and potential lifestyle changes, play important roles in overall patient management. Pharmacotherapy with cilostazol has been shown to improve maximal and pain-free walking distances. Uncontrolled and severely debilitating intermittent claudication may require revascularization.

Apolipoprotein E polymorphism and atherosclerosis

The relationship between apolipoprotein (apo) E and vascular disease has been the subject of a considerable amount of research. However, this relationship is far from clearly defined. This deficiency appears to be due to a multitude of factors. Among these are differences in ethnicity, age (and possibly gender), diagnostic criteria, and environmental factors (eg, diet and smoking) that have contributed to the contradictory findings. Several diseases and their treatment may also influence this relationship. There are also documented interactions between apo E genotypes and other genes or vascular risk factors. One possible clinically relevant application of identifying the apo E genotype could be to assess the response to a particular drug treatment. It may also be that apo E polymorphism will become a good predictor of vascular death (eg, from myocardial infarction or stroke) rather than an indicator of the risk of developing vascular disease but without an acute ischemic event. More research is required to define the place of apo E genotyping in the management of vascular disease in its various forms. Whatever the future brings, the evaluation of apo E genotypes will need to be rapid, cheap, and technically undemanding before this investigation becomes widely available and clinically relevant.

Serum apolipoprotein AI levels in atherosclerotic and diabetic patients

OBJECTIVE

To evaluate the association between Apolipoprotein AI (ApoAI), Apolipoprotein B100 (ApoB) and the presence of lower limb atherosclerotic occlusive disease.

MATERIALS AND METHODS

Serum lipids, lipoprotein fractions, ApoAI, ApoB and Lp(a) were measured in 52 patients (28 diabetics and 24 non-diabetics) with lower limb occlusive disease. They were evaluated according to patients' glucose and compared with those in 75 healthy controls.

RESULTS

There was a significant decrease in HDL-cholesterol and ApoAI serum levels (p = 0.000001) and an increase in Lp(a) (p = 0.000001) in patients as compared to controls. No difference was observed in total cholesterol, non HDL-cholesterol or triglycerides. Multiple regression analysis revealed a significant association between low ApoAI (or HDL) levels and the disease as well as between high Lp(a) levels and the disease. ApoAI (p = 0.0003), HDL-cholesterol (p = 0.00005) and total cholesterol (p = 0.01) levels were significantly lower in diabetic patients compared to non-diabetic patients. Lp(a) levels did not correlate with fasting glucose concentration. Multiple regression analysis revealed a significant association between low ApoAI (or HDL) levels and diabetes.

CONCLUSION

Decreased ApoAI appears to be a main component of the dyslipidaemic serum profile observed in patients with atherosclerotic occlusive disease of the lower extremities. Increased Lp(a) levels is an independent risk factor. Decreased HDL-cholesterol is also involved in the dyslipidaemic profile.

Femoral artery wall thickness and stiffness in evaluation of peripheral vascular disease in type 2 diabetes mellitus

Stiffening and thickening of arterial wall are two important components of atherosclerosis. The purpose of this study was to evaluate the effects of femoral artery wall stiffness on clinical manifestation of peripheral vascular disease (PVD) in type 2 diabetes mellitus. The subjects were 315 patients with type 2 diabetes. Presence of intermittent claudication and/or leg pain at rest and reduced ankle-brachial blood pressure index (ABI<0.9) were used as a subjective and an objective index of PVD, respectively. Femoral artery intima-media thickness (FA-IMT) and stiffness parameter beta (FA-stiffness beta) were measured by ultrasound methods. Symptomatic patients (N=58) showed greater values for both FA-IMT and FA-stiffness beta than those without symptom (N=257). Similarly, patients with reduced ABI (N=56) had greater FA-IMT and FA-stiffness beta than those without (N=259). However, correlation between FA-IMT and FA-stiffness beta was not impressive, especially in the symptomatic patients. To evaluate the effect of FA-stiffness beta on PVD symptoms, the subjects were divided into three subgroups according to FA-IMT, and then FA-stiffness beta was compared between those with and without PVD symptoms in each subgroup. The symptomatic patients had greater FA-stiffness beta values than the asymptomatic subjects in all the three subgroups. Multiple logistic regression analysis indicated that the presence of PVD symptoms was associated more closely with increased FA-stiffness beta than with increased FA-IMT, whereas reduced ABI was associated more closely with FA-IMT than with FA-stiffness beta. These data suggest that stiffening of arterial wall has a significant impact on PVD manifestations, particularly on the leg symptoms, in patients with type 2 diabetes.

Serum Lp(a) lipoprotein levels in patients with atherosclerotic occlusive disease of the lower extremities

OBJECTIVE

To evaluate the association between Lp(a) lipoprotein levels, other serum lipids and the presence of lower limb atherosclerotic occlusive disease.

MATERIALS AND METHODS

Angiographic findings in 36 patients were related to serum Lp(a). Total cholesterol, triglycerides, LDL-cholesterol, HDL-cholesterol and Lp(a) levels were compared with those of 73 age- and sex-matched healthy controls.

RESULTS

Atheromatous lesions were localised in the femoropopliteal ( approximately 60%) and aortoiliac ( approximately 40%) segments. The number of stenosed arteries was > or =2 and the range of stenosis severity was between 40% and 100%. There was a significant increase in serum Lp(a) (p= 0.000001) and a decrease in serum HDL (p= 0.000009) levels in patients compared to controls. No difference was observed in total cholesterol, LDL-cholesterol or triglyceride. However, the ratio of total cholesterol/HDL-cholesterol was significantly higher (p= 0.005) in patients.

CONCLUSION

A dyslipidaemic serum profile, characterised by increased Lp(a) levels and decreased HDL-cholesterol levels, is associated with atherosclerotic occlusive disease of the lower extremities.

Relationship of abdominal adiposity and dyslipemic status in women with a common mutation in the lipoprotein lipase gene. The REGICOR investigators

Abdominal obesity constitutes an important risk factor for cardiovascular disease. Hypertriglyceridemia and low high-density lipoprotein (HDL) cholesterol concentration constitute the major lipid alterations observed in obesity. A common variant of the lipoprotein lipase (LPL) gene, the HindIII polymorphism, has been found to be associated with changes in triglyceride and HDL-cholesterol levels. We have investigated the impact of the LPL HindIII polymorphism on the relationship between abdominal adiposity and lipoprotein concentrations in 156 randomly selected women in a cross-sectional study conducted in the province of Gerona, in the northeast of Spain. The waist-to-hip ratio was used as an estimate of regional fat distribution. Serum lipid and lipoprotein measurements as well as lipoprotein lipase-HindIII genotypes were determined. Percentile 50 of waist-to-hip ratio (WHR) (0.81) was used as a cutoff to define low or high WHR groups, which significantly differed in blood pressure and lipid trait concentrations. Serum triglyceride concentrations and mean log triglyceride-to-HDL-cholesterol ratio were significantly higher in H+ homozygous women compared with H- carriers. Whereas no statistically-significant differences were observed in HDL-cholesterol concentration and log triglyceride-to-HDL-cholesterol ratio of H- carriers between WHR groups, H+ homozygous women showed significant differences in these lipid traits. It is noteworthy that high-WHR H- carrier women showed a mean HDL-cholesterol value similar to those of both genotypes in the low WHR group. A statistically significant interaction between WHR and genotype was observed for HDL-cholesterol concentration (P=0. 027) and log triglyceride-to-HDL-cholesterol ratio (P=0.040). These results stress the compensating effects that weight loss may have on women with adverse genetic factors. From a complementary viewpoint, the presence of the H- allele seems to confer a protective lipid profile, even when an adverse anthropometric factor such as abdominal adiposity is present.

Effect of physical activity on lipid levels in a population-based sample of men with and without the Arg192 variant of the human paraoxonase gene

The prevalence of cardiovascular risk factors in Gerona, Spain, is high for the low myocardial infarction incidence and mortality rates in the province. Physical activity is a protective factor against coronary heart disease. We investigated whether the genetic variants Q and R of the paraoxonase Gln-Arg 192 polymorphism were involved in different responses of lipids to physical activity. Serum triglycerides, HDL-cholesterol concentrations, and the paraoxonase Gln-Arg 192 polymorphism were determined in 262 men randomly selected from a representative population sample in a cross-sectional study conducted in Gerona, Spain. The Minnesota Leisure Time Physical Activity Questionnaire was used to assess energy expenditure in leisure time physical activity. No differences were found in lipid levels among tertiles of physical activity distribution in subjects with the QQ genotype. However, R carriers showed a significant decreasing trend in triglyceride levels and in log-triglyceride-to-HDL-cholesterol ratio and a significant increasing trend in HDL-cholesterol concentration with the amount of physical activity. R carriers included in the low tertile of physical activity distribution had HDL-cholesterol levels significantly lower than those of QQ homozygous men in the same physical activity category (1.04 mmol/L vs. 1.22 mmol/L, P = 0.024). R carriers of the higher tertile of physical activity distribution showed the most favorable lipid profile in this genetic group. A statistically-significant interaction between paraoxonase genotypes and physical activity was observed for log triglycerides (P = 0.018), HDL-cholesterol concentration (P = 0.017), and log triglyceride-to-HDL-cholesterol ratio (P = 0.008). The beneficial association of the amount of physical activity and lipid traits found in men with the R allele suggests that this population subgroup needs to be physically active to achieve a favorable lipoprotein phenotype similar to that observed in QQ homozygous men.

Compliance to multiple interventions in a high risk population

PURPOSE

Assess compliance with study medications and examine reasons for noncompliance. Individuals with peripheral arterial disease present the clinician with a unique combination of symptoms and therapeutic needs; the treatment of this population has not been adequately studied.

METHODS

The Arterial Disease Multiple Intervention Trial was a randomized double-blind placebo-controlled trial that randomized 468 participants to a combination of antioxidants, niacin and warfarin or matching placebos. Men and women (mean age 65 yrs) with peripheral arterial disease and low-density lipoprotein (LDL) < 190 mg/dl were enrolled and followed for one year. Compliance to the study medications was measured by pill count for each medication. An overall measure of compliance was determined by combining pill counts from all study visits.

RESULTS

Mean overall pill counts ranged from 88 to 94% in the eight treatment groups. No statistically significant differences were found in mean pill counts over time or between active and placebo groups. History of coronary artery disease and number of follow-up visits were associated with higher overall pill counts while low compliance during screening was associated with lower counts during follow-up. Participants with an overall mean pill count < 80% had more adverse events compared to those with a higher count. Side effects were reported as the reason for missing pills significantly more often in the active versus placebo niacin group.

CONCLUSIONS

Individuals with peripheral arterial disease were able to comply with the complex drug regimen. The ability of this drug combination to reduce cardiovascular events and improve quality of life warrants study.

Apolipoprotein E and atherosclerosis: insight from animal and human studies

Major advances have been made in our understanding of the role of apolipoprotein E (apoE) in the onset and development of atherosclerosis. Increasing evidence from both animal and human studies suggests that apoE is able to protect against atherosclerosis by: a) promoting efficient uptake of triglyceride-rich lipoproteins from the circulation; b) maintaining normal macrophage lipid homeostasis; c) playing a role in cellular cholesterol efflux and reverse cholesterol transport; d) acting as an antioxidant; e) inhibiting platelet aggregation; and f) modulating immune function. In humans, apoE is polymorphic, and this genetic variation has a strong effect on its antiatherogenic characteristics. Thus, compared to the epsilon3 allele, the epsilon4 allele promotes atherosclerosis, whereas the epsilon2 allele is either pro- or anti-atherogenic, depending on the influence of both environmental and genetic factors. ApoE and its gene are prime targets for therapeutic intervention aimed at preventing or treating atherosclerotic vascular disease.

Rationale and design of the Arterial Disease Multiple Intervention Trial (ADMIT) pilot study

The primary objectives of the pilot study were to: (1) evaluate the feasibility of recruiting patients with peripheral arterial disease (PAD); (2) measure the efficacy and safety of high-density lipoprotein (HDL)-raising treatment, low-density lipoprotein (LDL)-lowering therapy, antioxidant therapy, antithrombotic therapy, and their combinations; and (3) assess adherence to a complex multiple drug regimen. Secondary objectives included measurement of the effect of the interventions on prespecified biochemical markers, maintenance of therapy masking (in particular with niacin), and measurement of the intervention's impact on functional status and on quality of life. To date, no secondary prevention trial has been conducted specifically among patients with PAD. Intermittent claudication affects about 0.5% to 1.0% of persons aged >35 years. There is a striking increase in incidence of PAD with age, particularly among those aged >50 years in both sexes, although men are twice as likely as women to develop PAD. The Arterial Disease Multiple Intervention Trial was a double-blind randomized pilot trial of 468 participants with documented PAD. A 2 x 2 x 2 factorial design was used to evaluate the effect of 3 interventions. The pilot incorporated several major novel design features: first, the use of a simple noninvasive method (measurement of ankle brachial index) to identify a population with either symptomatic or asymptomatic PAD; and second, a lipid modifying strategy to increase HDL with nicotinic acid in the intervention group while lowering LDL levels equally with an hydroxymethylglutaryl-coenzyme A reductase inhibitor as needed in the intervention and control group. Two other arms, the antioxidant arm (consisting of beta-carotene and vitamins E and C) and the antithrombotic arm (using warfarin) were also added. Adherence to therapy was measured by pill count, and success in treatment was measured by the proportion of values in target range for HDL, LDL, and the international normalized ratio.

The severity of coronary atherosclerosis in type 2 diabetes mellitus is related to the number of circulating triglyceride-rich lipoprotein particles

The presence or absence of coronary artery disease (CAD) in diabetic patients has been related to the level of circulating plasma lipoproteins. This study examines whether there is a relationship between the actual severity of CAD and the plasma concentration of major classes of plasma lipoproteins (HDL, LDL, triglyceride-rich lipoproteins (TRL), and their Sf 12 to 60 and Sf 60 to 400 subfractions), particularly the numbers of lipoprotein particles, in men and women with type 2 diabetes. 174 diabetic patients (136 men, 38 women) who underwent angiography were studied. Nine specific coronary segments were scored. The population was divided into tertiles according to the angiographic severity of their coronary disease: mild CAD: coronary score 1 to 10; moderate CAD: coronary score 11 to 13; or severe CAD: coronary score 14 to 22. The main findings were that the numbers of particles (as reflected by the apoB levels) of the TRL were greater in those with moderate and severe disease than in those with mild disease (P = .001). There was a significant correlation between the coronary score and the apoB in TRL (P = .006). There were parallel but nonsignificant changes in triglyceride levels. ApoA-I was lower in patients with moderate and severe disease (P = .01). These differences were more striking in women than they were in men. There were no differences in plasma, LDL, or HDL cholesterol or in LDL apoB or Lp(a). Multiple linear regression analysis, when adjusted for sex, age, and BMI, showed that three lipid variables (TRL apoB, LDL cholesterol, and plasma apoA-I) significantly and independently predicted the coronary score. This study demonstrates that in type 2 diabetes, the severity of angiographically evaluated CAD is positively related to the numbers of TRL particles in the plasma. This relationship is stronger in women than in men, and it is independent of HDL and LDL.

Interaction of family history of atherosclerosis with atherogenic lipid traits in men with non-coronary atherosclerosis

Family history of atherosclerosis has been recognised as an nonmodifiable cardiovascular risk factor. Lipid levels, together with hypertension and diabetes, appear to have an inheritable component. The aim of the study was to ascertain whether lipoprotein abnormalities of 169 adult patients with non-coronary atherosclerosis were associated with a family history of atherosclerosis. Besides intermediate density lipopoprotein composition and Lp(a) levels, we focused on apo(a) and apo E phenotypes, LDL cholesterol/apo B ratio, VLDL triglyceride/HDL cholesterol ratio, and environmental factors. We found that patients with a family history of atherosclerosis had a higher prevalence of VLDL triglyceride/HDL cholesterol ratio above 1.8 (51.3% vs 34.7%) than patients without. Similarly, there was a significant inverse correlation between both considered ratios (r = -0.24, p < 0.05). The odds ratio of the presence of both abnormal ratios (4.60, 95% CI, 1.41-15.00) and low molecular weight apo(a) isoforms (3.30, 95% CI, 1.05-10.30 and family history of atherosclerosis was independent of smoking and hypertension. Apo(a) isoform size seems to be more important than Lp(a) concentrations in the family history of atherosclerosis risk determination. Subsequent analysis showed that patients with a family history of atherosclerosis had a greater-than-fourfold increased risk of having one or both abnormal ratios reflecting metabolic disturbances which probably constitute a combined trait. Family history of atherosclerosis may constitute a specific lipoprotein-related marker of atherosclerosis. Such a marker often precedes the onset of overt disease and may contribute to identifying patients with an atherogenic lipoprotein profile even in the absence of classical lipid risk factors.

APO E polymorphism in Spanish and Moroccan populations

Apolipoprotein E (apoE) gene polymorphism was analyzed by polymerase chain reaction in one Moroccan and six Spanish populations, a total of 660 individuals. No significant differences were observed between samples, and the mean relative frequencies (with 95% confidence intervals) found were 0.104 (0.069-0.139) for the epsilon4 allele, 0.855 (0.813-0.897) for epsilon3 and 0.041 (0.015-0.067) for epsilon2. Frequencies of the epsilon4 allele were low in comparison to Northern European populations, but similar to those reported for other South-European populations. The presence of a rare mutation, E2 Christchurch, in one Basque individual was confirmed by sequence analysis.

Arterial Damage, Triglycerides, Apolipoprotein, and Lp-(a) Values in PVD Patients

The aim of the study was to provide a detailed apolipoproteic profile in stage II peripheral vascular disease (PVD) patients and to ascertain whether lower ankle/ arm pressure index (API) values were associated with a worse profile.

Apolipoproteins of 83 stage II PVD patients (average age 64.7 ± 9.3 years) were selected and compared with those of a group of 44 normal control subjects, similar in terms of age, sex, and smoking and eating habits. Neither PVD patients nor controls had ever received lipid-lowering agents or defined dietary treatment. A diagnosis of PVD was confirmed by an API of <0.85. Arteriopathic patients were also split into two groups, depending on their API values, similar in terms of age, sex and smoking habits: API values of one group (n = 38) were ≥0.6, those of the other group (n = 45) were <0.6. The following biohumoral parameters were considered: fasting glycemia, total cholesterol, triglycerides (TGs); high-density lipoprotein cholesterol (HDL-C); low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C), total cholesterol (TC)/HDL-C (TC/ HDL-C), Apoproteins (Apos) AI, AII, B, CII, CIII, and E; and lipoprotein a [Lp(a)].

HDL-C and Apo AI were lower ( p < 0.01), while TC/ HDL-C ratios, Apo B, and Apo CII were higher ( p < 0.01) in PVD patients compared with controls. The comparison between the two PVD groups with different API values showed higher blood TG and VLDL-C values for the patients with lower API values (p < 0.05), indicating a relationship between hypertriglyceridemia and greater arterial damage. Key Words: Peripheral arterial occlusive disease-Triglyceride-Lipoprotein a.

Interrelationship of triglyceride-rich lipoproteins, serum lipoprotein (a) concentration and apolipoprotein(a) size

At present, the biochemical mechanisms underlying lipoprotein(a) (Lp(a)) metabolism are not fully understood. We analysed sera from 202 patients with atherosclerotic disease and 109 healthy subjects as a control group to investigate the possible relationship between triglyceride-rich lipoproteins (TRL) and serum lipoprotein(a) levels. To assess the influence of apolipoprotein (apo) (a) isoforms on the Lp(a)-TRL association, the apo(a) phenotypes of 177 patients and 95 controls were included in the analysis. Patients with atherosclerotic disease showed triglyceride levels almost within the normal range. There was no significant correlation between serum Lp(a) levels and triglyceride concentrations, or between Lp(a) and TRL levels in either group. When a subset of subjects from each group with serum triglycerides above 1.7 mmol l-1 was considered, a significant negative correlation between lipid concentration of very low density lipoproteins (VLDL) and serum Lp(a) levels was found only in patients. Control subjects with triglyceride levels under or over 1.7 mmol l-1 showed similar median Lp(a) levels (0.06 gl-1), in contrast to atherosclerotic patients, in whom median Lp(a) concentration was higher in the subset with serum triglycerides under 1.7 mmol l-1 than in those with triglyceride concentration above this value (0.16 vs. 0.13 gl-1). When patients with triglyceride concentrations above 1.7 mmol l-1 were classified into quartiles according to VLDL lipid concentration, subjects with the highest quartiles showed the lowest Lp(a) median levels. Despite the dependence of the Lp(a) concentration on apo(a) size isoforms, we found no effect of apo(a) genetic polymorphism on triglyceride levels or on TRL concentrations. We conclude that the variation in TRL metabolism may constitute a source of variation in serum Lp(a) concentrations that is independent of the genetically determined apo(a) molecule size.

Apolipoprotein E polymorphism influence on lipids, apolipoproteins and Lp(a) in a Spanish population underexpressing apo E4

The apolipoprotein E (apo E) polymorphism in a Spanish working population of Tenerife (Canary Islands, Spain) was analyzed. The distribution of apo E alleles (epsilon 3, 0.850; epsilon 2, 0.075; epsilon 4, 0.075) and phenotypes (E3/3, 72.6%; E3/4, 13%; E3/2, 11.5%; E4/4, 0.8%; E2/2, 1.5%; E4/2, 0.5%) was significantly different from those of a combined Caucasian population owing to a lower frequency of apo E4. We have also investigated the effect of apo E polymorphism on serum levels of cholesterol, LDL-cholesterol, HDL-cholesterol, Lp(a) and apolipoproteins A-I, B and E. The average effect of E4 (in whole sample and men only, respectively) was to raise serum levels of total cholesterol (by 4.1 mg/dl and 8.3 mg/dl), LDL-cholesterol (by 6.5 mg/dl and 9 mg/dl), and apo B (5.3 mg/dl and 4.5 mg/dl). The average effect of E2 was to lower serum levels of total cholesterol (by 14.8 mg/dl mg/dl and 8.3 mg/dl), LDL-cholesterol (by 20.2 mg/dl and 15.5 mg/dl) and apo B (11.5 mg/dl and 6.5 mg/dl), and to raise apo E (1.14 mg/dl and 3.4 mg/dl and 3.4 mg/dl). We found significantly higher serum triglyceride levels in individuals carrying E4, but no differences were found in serum HDL-cholesterol, apo A-I or Lp(a) by alleles. Data confirm previous reports about an underexpression of apo E4 in societies living in Southern Europe, and its repercussion in a more beneficial lipid profile and relatively low cardiovascular mortality rate in the Mediterranean region.

Secondary prevention of coronary heart disease in patients with extracoronary atherosclerosis: a need for accuracy of low density lipoprotein determination

According to the new guidelines of the National Cholesterol Education Program (NCEP) for secondary prevention in adults with evidence of coronary heart disease or other clinical atherosclerotic disease, lipoprotein analysis is required and classification is based on low density lipoprotein (LDL) cholesterol. The aim of the present study was to analyze the reliability of calculated LDL cholesterol by the Friedewald formula compared with measured LDL cholesterol after separation by ultracentrifugation in 202 male patients with extracoronary atherosclerosis (100 patients with ischemic cerebrovascular disease and 102 patients with peripheral vascular disease) and in 117 health control subjects. Calculated LDL cholesterol coincided with measured LDL cholesterol, with less than 10% error, in 118 patients (58.4%) with extracoronary atherosclerosis and in 87 controls (74.4%). Calculated LDL cholesterol was overestimated, with an error of 10% or more compared with measured LDL cholesterol, in 34.6% of patients and 22.2% of controls, and underestimated in 6.9% and 3.4% respectively. Despite a good correlation between calculated and measured LDL cholesterol, the intraclass correlation coefficients demonstrate a poor concordance between calculated and measured LDL cholesterol, both in patients and controls. The authors underline the need for caution in assessing the reliability of calculated LDL cholesterol.

Prevalence and association of atherosclerosis at three different arterial sites in patients with type III hyperlipoproteinemia

We have examined the prevalence of clinically significant atherosclerosis in 78 patients with type III hyperlipoproteinemia (HLP) and homozygosity for apolipoprotein (apo) E2. Forty-six of these individuals (59%) had no atherosclerosis, 32 patients (41%) had atherosclerosis, i.e., atherosclerosis of the extracranial carotid arteries (CAA), coronary arteries (CAD) or/and peripheral arteries of the legs (PVD), either singly or in combination. No association could be shown with respect to the co-prevalence of atherosclerotic lesions at these different arterial sites, except for the high predictive value (pv = 0.88, P = 0.006) of CAA for the presence of PVD. Hence, documentation of atherosclerosis under clinical aspects at one of these exposed arterial territories does not allow a reliable prediction of generalised atherosclerosis or local atherosclerosis at other sites of the arterial tree in individuals with this familial lipoprotein disorder. Therefore, assessment of the extent of clinically significant atherosclerosis in type III HLP patients should include careful and thorough examination of the extracranial carotid arteries, the coronary arteries, and the peripheral arteries of the legs.

Effect of fluvastatin on intermediate density lipoprotein (remnants) and other lipoprotein levels in hypercholesterolemia

The accelerated atherosclerosis in diseases associated with elevated remnant lipoprotein levels has directed interest toward the response of this lipoprotein species to lipid-lowering treatment. The effect of fluvastatin--a synthetic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor--was compared with that of placebo on parameters of remnant metabolism in 57 patients with moderate hypercholesterolemia, but not heterozygous familial hypercholesterolemia, type III hyperlipidemia, or endogenous hypertriglyceridemia. Fluvastatin therapy resulted in decreases versus baseline in plasma total cholesterol, low density lipoprotein cholesterol (LDL-C) and LDL apolipoprotein (apo) B levels of 18%, 20%, and 18%, respectively (p < 0.01). Plasma parameters related to remnant metabolism were also significantly decreased: intermediate density lipoprotein by 43% and apo E by 22% (p < 0.01). The percent decrease in plasma intermediate density lipoprotein cholesterol level was twice that of LDL-C and 50% greater than the decrease seen in very low density lipoprotein cholesterol (VLDL-C), which was decreased by 28%. Total triglycerides were reduced by 11% and VLDL apo B by 24%, whereas high density lipoprotein cholesterol (HDL-C) rose significantly by 8%, HDL2-C by 24%, and HDL3-C by 3%. There were no increases in apo A-I levels compared with placebo nor any significant change in plasma lipoprotein(a) levels. The composition of LDL and VLDL particles did not appear to be altered by therapy, as assessed by the LDL-C:LDL-B, VLDL-C:VLDL-B, or triglyceride:VLDL-B ratios.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparative study of two hormone replacement therapy regimens on safety and efficacy variables

OBJECTIVE

To assess the effect of tibolone on endometrial safety, plasma estradiol concentrations, lipid metabolism and climacteric symptoms in comparison to sequential conjugated equine estrogens and medroxyprogesterone acetate in postmenopausal women.

METHODS

In a randomised, open-label, 6-cycle, group-comparative study, the effects on the aforementioned parameters were studied with tibolone 2.5 mg/day (N = 13) continuously, and with conjugated equine estrogens 0.625 mg/day continuously, combined with medroxyprogesterone acetate 5 mg/day (N = 11) (CEE/MPA) sequentially, during 12 days of each 28-day cycle. Within-group statistical analysis was performed with Student's t-test for paired samples, whereas between-group statistics were performed using the Student's t-test for independent groups.

RESULTS

Cytological evaluation revealed no endometrial stimulation in either group. In the tibolone group, there were no effects on estradiol levels, whereas in the CEE/MPA group, an increase in total and non-SHBG-bound estradiol plasma levels was reported. In the tibolone group, there were significant decreases in plasma total cholesterol, triglycerides, HDL-cholesterol and VLDL-cholesterol, whereas no significant changes in LDL-cholesterol and IDL-cholesterol were reported. In the CEE/MPA group there were significant decreases in plasma total cholesterol, HDL-cholesterol and LDL-cholesterol, whereas there were no significant changes in triglycerides, IDL-cholesterol and VLDL-cholesterol. Climacteric symptoms, particularly vasomotor episodes, decreased similarly in both groups.

CONCLUSIONS

Both tibolone and CEE/MPA were safe with respect to effects on the endometrium and both treatments induced changes in the plasma profiles of certain lipid and lipoprotein parameters. However, the overall clinical implications of these changes are unknown. Finally, both regimens were equally effective in the treatment of climacteric symptoms.

Comparative study of risk factors in patients undergoing coronary or femoropopliteal artery bypass grafting

OBJECTIVE

To compare risk factors in two populations of patients with advanced atheroma requiring coronary or femoropopliteal artery bypass grafting to try to account for the different localisations of vascular disease.

DESIGN

Cross sectional epidemiological study.

SETTING

Cardiovascular surgery department of a university hospital.

SUBJECTS

464 men (mean age 59.25 (SD 8.57) years) undergoing coronary artery bypass grafting; 74 men (mean age 56.28 (13.3) years) undergoing femoropopliteal artery bypass grafting; and 204 control men (mean age 45.07 (6.59) years) who had been recruited in a preventive medicine department.

INTERVENTIONS

Blood samples were drawn 24 hours before surgery.

METHODS

Lipid and lipoprotein concentrations were measured for each patient and with adjustment for age were compared by analysis of covariance. The main risk factors (smoking, arterial hypertension, obesity, and diabetes) were determined by a standardised history, and the chi 2 test was used to compare the results in the two patient groups. Pairwise comparisons between the three populations were performed by logistic discriminant analysis.

RESULTS

Both patient groups showed a significant rise in triglyceride concentration and in the ratio of total cholesterol to high density lipoprotein cholesterol (R1) and a drop in apolipoprotein AI and high density lipoprotein cholesterol concentrations. Disturbances were greater in patients undergoing coronary artery bypass grafting than in those undergoing femoropopliteal artery bypass grafting for the R1 ratio, apolipoprotein B concentration, and the ratio of apolipoprotein AI to apolipoprotein B (R2). A higher proportion of smokers was found in the femoropopliteal bypass group than in the coronary bypass group, whereas were often obese. Logistic discriminant analysis with adjustment for age and with the coronary bypass as the reference group selected three factors: smoking, the R2 ratio, and obesity.

CONCLUSION

Disturbances in lipid and apoprotein concentrations varied with respect to bypass site. Other risk factors played a part in accelerating the atherogenic process, especially smoking in patients undergoing femoropopliteal artery bypass grafting and, to a lesser degree, obesity in patients undergoing coronary artery bypass grafting.

Apolipoproteins C-II and C-III in peripheral arterial disease

Apolipoprotein (apo) C-II and apo C-III serum concentrations were investigated in 119 normotriglyceridemic male subjects with peripheral arterial disease (PAD) or coronary heart disease (CHD) or without clinical manifestations of atherosclerotic disease. All subjects included in the study had similar blood levels of total cholesterol (< 400 mg/dL). High-density lipoproteins cholesterol (HDL-C) subfractions and apo A-I serum levels were significantly lower in CHD patients, as were apo A-I/apo B and HDL-cholesterol/total cholesterol ratios. Apo C-II and apo C-III showed similar serum concentrations in all three groups of subjects, but apo C-II/apo C-III ratio was significantly lower in PAD patients as compared with that in CHD patients and control subjects. This study confirms that PAD may be associated with a particular lipoprotein derangement that primarily involves very low-density lipoprotein catabolism.

The prevention of cardiovascular disease. Emphasis on secondary prevention

Atherosclerosis is a progressive disease affecting all major arteries. Clinical evidence of atherosclerosis increases the risk of subsequent morbid and mortal events fivefold to sevenfold over the next 5 to 10 years. The same risk factors contribute to the initial development of CVD events as to their recurrence. Both coronary and noncoronary events, such as stroke or PAD, reflect the severity of the underlying atherosclerotic process and strongly predict future excess CVD morbidity and mortality. Short-term and long-term survival depends on modifying the risk factors that contribute to CVD events. Although absolute proof of benefit for secondary prevention does not exist for all risk factors, the data from primary prevention trials and the secondary prevention trials that have been done argue strongly for aggressive intervention. Benefit has been demonstrated for smoking cessation, cholesterol reduction, and blood pressure control. Selected patients may benefit from additional medical, procedural, or surgical interventions to prolong life, such as beta-blocking agents, aspirin, or carotid endarterectomy. Many secondary prevention measures are a cost-effective way to reduce the substantial morbidity and mortality due to CVD. Contrary to primary prevention, even modest treatment effects from secondary prevention efforts can benefit large numbers of patients. Finally, secondary prevention may be more successful because patients with clinical evidence of CVD may be more highly motivated than their healthy counterparts to make and maintain lifestyle changes.

Genetic heterogeneity of apolipoprotein E and its influence on plasma lipid and lipoprotein levels

Apolipoprotein E (apoE) is one of the major protein constituents of chylomicron and very-low-density lipoprotein (VLDL) remnants and plays a central role as a ligand in the receptor-mediated uptake of these particles by the liver. Including the most common variant, apoE3, 30 apoE variants have been characterized. At present, 14 apoE variants have been found to be associated with familial dysbetalipoproteinemia, a genetic lipid disorder characterized by elevated plasma cholesterol and triglyceride levels and an increased risk for atherosclerosis. Seven apoE variants were found to be associated with other forms of hyperlipoproteinemia. This report presents an overview of all currently known apoE variants and their effects on lipoprotein metabolism.