Increased ApoB in Small Dense LDL Particles Predicts Premature Coronary Artery Disease

Increased Circulating Levels of PCSK9 and Pro-Atherogenic Lipoprotein Profile in Pregnant Women with Maternal Supraphysiological Hypercholesterolemia

Maternal physiological hypercholesterolemia (MPH) occurs during pregnancy to assure fetal development. Some pregnant women develop maternal supraphysiological hypercholesterolemia (MSPH) characterized by increased levels of low-density lipoprotein (LDL). We aim to determine if proprotein convertase subtilisin/kexin type 9 (PCSK9) levels (a protein that regulate the availability of LDL receptor in the cells surface), as well as the composition and function of LDL, are modulated in MSPH women. This study included 122 pregnant women. Maternal total cholesterol (TC), LDL, triglycerides and PCSK9 increased from first (T1) to third trimester (T3) in MPH women. At T3, maternal TC, LDL, PCSK9 and placental abundances of PCSK9 were significantly higher in MPSH compared to MPH. Circulating PCSK9 levels were correlated with LDL at T3. In MSPH women, the levels of lipid peroxidation and oxidized LDL were significantly higher compared to MPH. LDL isolated from MSPH women presented significantly higher triglycerides and ApoB but lower levels of ApoAI compared to MPH. The formation of conjugated dienes was earlier in LDL from MSPH and in endothelial cells incubated with these LDLs; the levels of reactive oxygen species were significantly higher compared to LDL from MPH. We conclude that increased maternal PCSK9 would contribute to the maternal elevated levels of pro-atherogenic LDL in MSPH, which could eventually be related to maternal vascular dysfunction.

Elevated sdLDL level and LDLR rs688 C>T mutation are independent risk factors for ischemic stroke

PURPOSE

To investigate the level of sdLDL and the frequency of LDLR rs688 polymorphisms, as well as the correspondence between them, and to analyze the risk factors for stroke.

METHODS

Between March 2019 and November 2019, 232 patients diagnosed with stroke and 96 health volunteers were enrolled in Quanzhou First Hospital. Subjects were divided into control group, ischemic stroke group (n=120) and hemorrhagic stroke group (n=112). The level of sdLDL and the genotypes and allele frequencies of LDLR rs688 were compared between groups, the correspondence was analyzed with Spearman method. Risk factors were analyzed with Binary logistic regression.

RESULTS

The level of sdLDL was highest in ischemic group, followed by hemorrhagic stroke group and lowest control group. The differences of genotypes and allele frequencies of LDLR rs688 were significant in ischemic stroke group (p=0.0000 and 0.0000 respectively), while were not significant in hemorrhagic group (p=0.184 and .0137). There was no obvious correlation between the level of sdLDL and LDLR rs688 genotype by Spearman analysis (p=0.116).

CONCLUSION

Elevated sdLDL level and the C>T mutation of LDLR rs688 are independent risk factors for ischemic stroke, while they are not correlative to hemorrhagic stroke. The surveillance and regulatory of sdLDL level, the detection of LDLR rs688 gene polymorphisms may contribute to the prevention of ischemic stroke.

Small Dense Low-Density Lipoprotein Cholesterol and Cardiovascular Risk in Statin-Treated Patients with Coronary Artery Disease

Aim: We investigated the relationship between small dense low-density cholesterol (sdLDL-C) and risk of major adverse cardiovascular events (MACE) in patients treated with high- or low-dose statin therapy.

Methods: This was a prospective case-cohort study within the Randomized Evaluation of Aggressive or Moderate Lipid-Lowering Therapy with Pitavastatin in Coronary Artery Disease (REAL-CAD) study, a randomized trial of high- or low-dose (4 or 1 mg/d pitavastatin, respectively) statin therapy, in patients with stable coronary artery disease (CAD). Serum sdLDL-C was determined using an automated homogenous assay at baseline (randomization after a rule-in period, ＞1 month with 1 mg/d pitavastatin) and 6 months after randomization, in 497 MACE cases, and 1543 participants randomly selected from the REAL-CAD study population.

Results: High-dose pitavastatin reduced sdLDL-C by 20% than low-dose pitavastatin (p for interaction ＜0.001). Among patients receiving low-dose pitavastatin, baseline sdLDL-C demonstrated higher MACE risk independent of LDL-C (hazard ratio [95% confidence interval], 4th versus 1st quartile, 1.67 [1.04–2.68];p for trend=0.034). High-dose (versus low-dose) pitavastatin reduced MACE risk by 46% in patients in the highest baseline sdLDL-C quartile (＞34.3 mg/dL; 0.54 [0.36–0.81];p=0.003), but increased relative risk by 40% in patients with 1st quartile (≤ 19.5 mg/dL; 1.40 [0.94–2.09];p=0.099) and did not alter risk in those in 2nd and 3rd quartiles (p for interaction=0.002).

Conclusions: These findings associate sdLDL-C and cardiovascular risk, independent of LDL-C, in statin-treated CAD patients. Notably, high-dose statin therapy reduces this risk in those with the highest baseline sdLDL-C.

Hypolipidemic effect of Fragarianilgerrensis Schlecht. medicine compound on hyperlipidemic rats

BACKGROUND

Fragarianilgerrensis Schlecht. medicine compound (FN-MC) is a kind of Chinese herbs' compound consisted of Fragarianilgerrensis Schlecht. and Centella asiatica (L.) Urban. The study was to investigate the hypolipidemia effect of FN-MC in a hypolipidemic rat model.

METHODS

Male SD rats were randomly divided into five groups: normal-fat diet (NFD) group, high-fat diet (HFD) group, FN-MC (2 g/Kg) group, FN-MC (4 g/Kg) group and simvastatin (PDC) group. After FN-MC treatment, body weight, food intake, serum and hepatic biochemistry parameters of rats were measured and the pathological changes of liver and its cells were observed by optical microscope and transmission electron microscopy.

RESULTS

The results showed that FN-MC significantly decreased the levels of serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL-C), apolipoprotein B (ApoB) and hepatic malondialdehyde (MDA), while increased serum high-density lipoprotein (HDL-C), apolipoprotein A1 (ApoA1) and hepatic Superoxide Dismutase (SOD). FN-MC also improved the structure of liver and decreased the lipid drops in the cytoplasm significantly. In addition, FN-MC significantly decreased the weight gain and had no significant effects on food intake.

CONCLUSIONS

The study suggested that FN-MC exhibited strong ability to improve the dyslipidemia and prevent hepatic fatty deposition in rats fed with high-fat diet. Meanwhile, FN-MC exerted anti-obesity and antioxidant properties.

HIGHLIGHTS

Fragarianilgerrensis Schlecht. medicine compound possesses a hypolipidemic effect on hyperlipidemic rat model Fragarianilgerrensis Schlecht. medicine compound administration improves the antioxidant capacity of rats Fragarianilgerrensis Schlecht. medicine compound prevents hepatic fatty deposition.

Small dense low-density lipoprotein cholesterol is a promising biomarker for secondary prevention in older men with stable coronary artery disease

AIM

The study objective was to investigate whether small dense low-density lipoprotein cholesterol (sdLDL-C) is superior to low-density lipoprotein cholesterol (LDL-C) and other biomarkers to predict future cardiovascular events (CE) in secondary prevention.

METHODS

sdLDL-C measured by a homogeneous assay, remnant lipoprotein cholesterol, LDL particle diameter and other biomarkers were compared in 345 men aged ≥65 years with stable coronary artery disease. Baseline LDL-C was 100.5 ± 30.1 mg/dL. CE including cardiovascular death, onset of acute coronary syndrome, need for arterial revascularization, hospitalization for heart failure, surgery procedure for cardiovascular disease and hospitalization for stroke were monitored for 5 years.

RESULTS

CE occurred in 96 patients during the study period. LDL-C, sdLDL-C non-high-density lipoprotein cholesterol, apolipoprotein B, remnant lipoprotein cholesterol, glucose, glycated hemoglobin and brain natriuretic peptide were significantly higher; LDL particle diameter and apolipoprotein A-1 were significantly lower in patients with than in those without CE. Age-adjusted Cox regression analysis showed that sdLDL-C per 10 mg/dL, but not LDL-C, was significantly associated with CE (HR 1.206, 95% CI 1.006-1.446). A significant association of sdLDL-C and incident CE was observed in statin users (HR 1.252, 95% CI 1.017-1.540), diabetes patients (HR 1.219, 95% CI 1.018-1.460), patients without diabetes (HR 1.257, 95% CI 1.019-1.551) and patients with hypertriglyceridemia (HR 1. 376, 95% CI 1.070-1.770).

CONCLUSIONS

sdLDL-C was the most effective predictor of residual risk of future CE in stable coronary artery disease patients using statins and in high-risk coronary artery disease patients with diabetes or hypertriglyceridemia. Geriatr Gerontol Int 2018; 18: 965-972.

Interplay between proteins and metabolic syndrome-A review

Metabolic syndrome is characterized by hypertension; hyperglycemia; hypertriglyceridemia; reduced high-density lipoprotein cholesterol levels and abdominal obesity. Abundant data suggest that, compared with other people, patients meeting these diagnostic criteria have a greater risk of having substantial clinical consequences, the two most prominent of which are the development of diabetes mellitus and coronary heart disease. The metabolic syndrome is a health issue of epidemic proportions. Its prevalence in the world continues to increase, hand in hand with that of obesity. Protein, on the other hand, is the foundation of cell-building, especially in muscle tissue. The body needs protein to build not only muscle cells, but the cells of major organs, skin and red blood cells. For people with metabolic syndrome, one of the other functions of protein is to slow down the absorption of carbohydrates. When proteins are consumed with carbohydrates, it takes longer for the digestive system to break down that meal. This means that the sugar created from those carbohydrates is released at a slower rate, preventing spikes in both blood sugar and insulin. As the understanding of the metabolic syndrome evolves, it is likely that more comprehensive therapeutic options will become available.

Hypolipidaemic Effects of Gymnema sylvestre on High Fat Diet Induced Dyslipidaemia in Wistar Rats

INTRODUCTION

Hyperlipidaemia is a well known risk factor for cardiovascular diseases. Lifestyle modification can be the initial step to reduce cholesterol levels. There are various drugs which are used to control dyslipidaemia. Treatment of lipid abnormalities is a lifelong battle. Moreover, the safety and effectiveness of long term lipid lowering treatment are questionable. Gymnema Sylvestre (GS) is a well known herb with various medicinal properties.

AIM

To explore the hypolipidaemic activity of GS leaves extract.

MATERIALS AND METHODS

Adult healthy female wistar rats, 30 in number, divided into five groups, weighing 150- 200 g were used. Dyslipidaemia was induced in rats by feeding them on high fat diet for four weeks. For the next four weeks GS extract was used as test drug while Atorvastatin was used as standard drug. Blood sample was collected for estimation of lipid profile on day 0, week 4 and week 8. Data was recorded as mean±SEM (Standard error of mean). Paired t-test and one way Analysis of Variance (ANOVA) followed by Dunnett's post hoc test was used for comparison. A p-value <0.05 was considered statistically significant. SPSS Statistics 20 (IBM software) was used for the analysis.

RESULTS

Feeding rats with high fat diet for four weeks led to obesity and dyslipidaemia in rats. GS at both the doses (100mg/kg and 200mg/kg) significantly improved the lipid profile. Total Cholesterol (TC), Triglycerides (TG), Very Low Density Lipoprotein (VLDL) and Low Density Lipoprotein (LDL) values reduced significantly while that of High Density Lipoprotein (HDL) increased significantly. GS 200 mg/kg was found more effective than GS 100 mg/kg. GS improved the value of lipid profile significantly but the effect was found inferior to Atorvastatin.

CONCLUSION

From the present study it can be concluded that GS possess an effective hypolipidaemic effect. Hence it can be included as an add on therapy in dyslipidaemia after further confirmatory studies.

The Application of a Modified d-ROMs Test for Measurement of Oxidative Stress and Oxidized High-Density Lipoprotein

Reactive oxygen species (ROS) are involved in the initiation and progression of atherosclerosis. ROS-derived hydroperoxides, as an indicator of ROS production, have been measured by using the diacron reactive oxygen metabolites (d-ROMs) test, which requires iron-containing transferrin in the reaction mixture. In this study we developed a modified d-ROMs test, termed the Fe-ROMs test, where iron ions were exogenously added to the reaction mixture. This modification is expected to exclude the assay variation that comes from different blood iron levels in individuals. In addition, this Fe-ROMs test was helpful for determining the class of plasma lipoproteins that are hydroperoxidized. Low-density lipoprotein/very low-density lipoprotein (LDL/VLDL) and high-density lipoprotein (HDL) were purified by use of an LDL/VLDL purification kit and the dextran sulfate-Mg²⁺ precipitation method, respectively; their hydroperoxide contents were assessed by performing the Fe-ROMs test. The majority of the hydroperoxides were detected only in the HDL fraction, not in the LDL/VLDL. Further detailed analysis of HDLs by size-exclusion high-performance liquid chromatography revealed that the hydroperoxide-containing molecules were small-sized HDLs. Because HDL was shown to be the principal vehicle for the plasma hydroperoxides, this Fe-ROMs test is a beneficial method for the assessment of oxidized-HDL levels. Indeed, Fe-ROMs levels were strongly associated with the levels of oxidized HDL, which were determined by performing the malondialdehyde-modified HDL enzyme immunoassay. In conclusion, the Fe-ROMs test using plasma itself or the HDL fraction after dextran sulfate-Mg²⁺ precipitation is useful to assess the functionality of HDL, because the oxidation of HDL impairs its antiatherogenic capacity.

Fenofibrate/simvastatin fixed-dose combination in the treatment of mixed dyslipidemia: safety, efficacy, and place in therapy

Lipids disorder is the principal cause of atherosclerosis and may present with several forms, according to blood lipoprotein prevalence. One of the most common forms is combined dyslipidemia, characterized by high levels of triglycerides and low level of high-density lipoprotein. Single lipid-lowering drugs may have very selective effect on lipoproteins; hence, the need to use multiple therapy against dyslipidemia. However, the risk of toxicity is a concerning issue. In this review, the effect and safety of an approved combination therapy with simvastatin plus fenofibrate are described, with an analysis of pros and cons resulting from randomized multicenter trials, meta-analyses, animal models, and case reports as well.

Method for estimating high sdLDL-C by measuring triglyceride and apolipoprotein B levels

Background

We previously developed an assay to directly measure small dense (sd) low-density lipoprotein cholesterol (LDL-C) levels, which is not widely used in general clinical practice. Therefore, we propose a simpler method, “LDL window,” that uses conventional methods for estimating high sdLDL-C levels.

Methods

We analyzed our previous studies (2006–2008) on healthy subjects and patients with type 2 diabetes and coronary artery disease (CAD). The sdLDL-C level was measured using the precipitation method, and LDL size was determined using gradient gel electrophoresis. The “LDL window” comprises the estimation of LDL particle number and size. We adopted apolipoprotein B (apoB) for the estimation of the LDL particle number and used 110 mg/dL as the cutoff value for hyper-apoB. Triglycerides (TGs) are a powerful inverse determinant of LDL particle size. Therefore, we adopted TG for the estimation of the LDL particle size and used 150 mg/dL as the cutoff value for hyper-TG. Subjects were stratified into the following four subgroups: normal, hyper-TG, hyper-apoB, and hyper-TG/-apoB. Non-high-density lipoprotein cholesterol (non-HDL-C) is a surrogate marker for apoB; therefore, the “alternative LDL window” comprised non-HDL-C (cutoff, 170 mg/dL) and TG.

Results

The top quartile (Q4) of sdLDL-C (>31 mg/dL) doubled in patients with diabetes and CAD. The hyper-TG/-apoB group in the “LDL window” represented >90% Q4 and <4% Q1 and Q2, irrespective of the subjects. The sdLDL-C levels in the hyper-TG/-apoB group were 50% higher in patients with diabetes and CAD than those in controls. Similar results were obtained using the “alternative LDL window.”

Conclusions

Our proposed “LDL window” may help identify patients at high risk of CAD independent of LDL-C.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-017-0417-6) contains supplementary material, which is available to authorized users.

Causal Role of Alcohol Consumption in an Improved Lipid Profile: The Atherosclerosis Risk in Communities (ARIC) Study

INTRODUCTION

Health benefits of low-to-moderate alcohol consumption may operate through an improved lipid profile. A Mendelian randomization (MR) approach was used to examine whether alcohol consumption causally affects lipid levels.

METHODS

This analysis involved 10,893 European Americans (EA) from the Atherosclerosis Risk in Communities (ARIC) study. Common and rare variants in alcohol dehydrogenase and acetaldehyde dehydrogenase genes were evaluated for MR assumptions. Five variants, residing in the ADH1B, ADH1C, and ADH4 genes, were selected as genetic instruments and were combined into an unweighted genetic score. Triglycerides (TG), total cholesterol, high-density lipoprotein cholesterol (HDL-c) and its subfractions (HDL2-c and HDL3-c), low-density lipoprotein cholesterol (LDL-c), small dense LDL-c (sdLDL-c), apolipoprotein B (apoB), and lipoprotein (a) (Lp(a)) levels were analyzed.

RESULTS

Alcohol consumption significantly increased HDL2-c and reduced TG, total cholesterol, LDL-c, sdLDL-c, and apoB levels. For each of these lipids a non-linear trend was observed. Compared to the first quartile of alcohol consumption, the third quartile had a 12.3% lower level of TG (p < 0.001), a 7.71 mg/dL lower level of total cholesterol (p = 0.007), a 10.3% higher level of HDL2-c (p = 0.007), a 6.87 mg/dL lower level of LDL-c (p = 0.012), a 7.4% lower level of sdLDL-c (p = 0.037), and a 3.5% lower level of apoB (p = 0.058, poverall = 0.022).

CONCLUSIONS

This study supports the causal role of regular low-to-moderate alcohol consumption in increasing HDL2-c, reducing TG, total cholesterol, and LDL-c, and provides evidence for the novel finding that low-to-moderate consumption of alcohol reduces apoB and sdLDL-c levels among EA. However, given the nonlinearity of the effect of alcohol consumption, even within the range of low-to-moderate drinking, increased consumption does not always result in a larger benefit.

Lipids and lipid management in diabetes

Cardiovascular disease is more prevalent in type 1 and type 2 diabetes, and continues to be the leading cause of death among adults with diabetes. Although atherosclerotic vascular disease has a multi-factorial etiology, disorders of lipid metabolism play a central role. The coexistence of diabetes with other risk factors, in particular with dyslipidemia, further increases cardiovascular disease risk. A characteristic pattern, termed diabetic dyslipidemia, consists of increased levels of triglycerides, low levels of high density lipoprotein cholesterol, and postprandial lipemia, and is mostly seen in patients with type 2 diabetes or metabolic syndrome. This review summarizes the trends in the prevalence of lipid disorders in diabetes, advances in the mechanisms contributing to diabetic dyslipidemia, and current evidence regarding appropriate therapeutic recommendations.

Elevated small dense low-density lipoprotein cholesterol as a predictor for future cardiovascular events in patients with stable coronary artery disease

AIM

The aim of the present study was to investigate how small dense low-density lipoprotein cholesterol (sdLDL-C) compared with LDL-C affect the long-term prognosis in patients with stable coronary artery disease (CAD).

METHODS

sdLDL-C measured by heparin magnesium precipitation and LDL particle size measured by non-denatured gradient-gel electrophoresis were compared in 190 consecutive CAD patients who underwent coronary arteriography between 2003 and 2004 who did or did not develop cardiovascular events during a seven-year follow-up period. Cardiovascular events were death caused by cardiovascular diseases(CVDs), onset of acute coronary syndrome, need for coronary and peripheral arterial revascularization, hospitalization for heart failure, surgical procedure for any CVDs, and/or hospitalization for stroke.

RESULTS

First-time cardiovascular events were observed in 72 patients. Those who experienced cardiovascular events were older and had higher prevalence rates of hypertension and diabetes; significantly higher Gensini coronary atherosclerotic scores; significantly higher levels of sdLDL-C, sdLDL-C/LDL-C, and LDL-C/high-density lipoprotein cholesterol (HDL-C) ratios; and greater glycated hemoglobin(Hb)A1c and brain natriuretic peptide (BNP) levels. They also had significantly smaller LDL particle sizes, HDL-C, apolipoprotein A-1, and estimated glomerular filtration rate (GFR) compared with patients without cardiovascular events. Conversely, LDL-C, non-HDL-C, apolipoprotein B, remnantlike particle cholesterol, and high-sensitivity C-reactive protein (hs-CRP) levels were similar between the two groups. A Kaplan-Meyer event-free survival curve demonstrated that patients with sdLDL-C≥35 mg/dL (median level) had significantly poorer prognosis compared with those with lower sdLDL-C levels, while patients with LDL-C ≥100 mg/dL had a non-significantly lower survival rate.

CONCLUSION

These results confirm that sdLDL-C is a very promising biomarker to predict future cardiovascular events in the secondary prevention of stable CAD.

Small dense LDL cholesterol and coronary heart disease: results from the Framingham Offspring Study

OBJECTIVE

We sought to establish reference values for a new direct assay for small dense LDL cholesterol (sdLDL-C) and to measure sdLDL-C concentrations in patients with established coronary heart disease (CHD) vs controls.

METHODS

Direct LDL-C and sdLDL-C were measured in samples from 3188 male and female participants of the Framingham Offspring Study, including 173 men and 74 women with CHD.

RESULTS

Postmenopausal status and male sex were associated with higher sdLDL-C concentrations (P < 0.0001). Cholesterol-lowering medication use was more frequent (P < 0.0001) in CHD patients than in controls (46.8% vs 11.4% in men; 35.1% vs 8.8% in women). In men, mean LDL-C was lower in CHD than in controls (3.22 vs 3.51 mmol/L, P < 0.0001), whereas mean sdLDL-C concentrations were similar (0.83 vs 0.84 mmol/L, P = 0.609). In women, mean LDL-C was similar in CHD and controls (3.53 vs 3.46 mmol/L, P = 0.543), but mean sdLDL-C was higher (0.83 vs 0.68 mmol/L, P = 0.0015). The mean percentage of LDL-C as sdLDL-C was higher in both men and women with CHD than controls (P < 0.01). Increased LDL-C and sdLDL-C were found in 10.4% and 22.0% of men and in 24.3% and 27.8% of women with CHD, respectively.

CONCLUSIONS

Despite 4-fold greater cholesterol-lowering therapy use, CHD patients had mean LDL-C concentrations above the LDL-C goal of <2.6 mmol/L (<100 mg/dL). Although women with CHD had higher sdLDL-C concentrations than controls, this difference was not seen in men. These findings may explain some of the high residual risk of future CHD events in CHD patients.

Endocrine and metabolic effects of consuming beverages sweetened with fructose, glucose, sucrose, or high-fructose corn syrup

Our laboratory has investigated 2 hypotheses regarding the effects of fructose consumption: 1) the endocrine effects of fructose consumption favor a positive energy balance, and 2) fructose consumption promotes the development of an atherogenic lipid profile. In previous short- and long-term studies, we showed that consumption of fructose-sweetened beverages with 3 meals results in lower 24-h plasma concentrations of glucose, insulin, and leptin in humans than does consumption of glucose-sweetened beverages. We have also tested whether prolonged consumption of high-fructose diets leads to increased caloric intake or decreased energy expenditure, thereby contributing to weight gain and obesity. Results from a study conducted in rhesus monkeys produced equivocal results. Carefully controlled and adequately powered long-term studies are needed to address these hypotheses. In both short- and long-term studies, we showed that consumption of fructose-sweetened beverages substantially increases postprandial triacylglycerol concentrations compared with glucose-sweetened beverages. In the long-term studies, apolipoprotein B concentrations were also increased in subjects consuming fructose, but not in those consuming glucose. Data from a short-term study comparing consumption of beverages sweetened with fructose, glucose, high-fructose corn syrup, and sucrose suggest that high-fructose corn syrup and sucrose increase postprandial triacylglycerol to an extent comparable with that induced by 100% fructose alone. Increased consumption of fructose-sweetened beverages along with increased prevalence of obesity, metabolic syndrome, and type 2 diabetes underscore the importance of investigating the metabolic consequences of fructose consumption in carefully controlled experiments.

Cholesterol Profile Measurement by Vertical Auto Profile Method

Vertical auto profile (VAP) method is a direct single test for measuring comprehensive lipoprotein cholesterol profile. It is based on a well-established method of ultracentrifugation that uses vertical rotor and single density gradient spin. VAP provides cholesterol concentrations of total lipoprotein, high-density lipoprotein (HDL), low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL), lipoprotein(a) (Lp(a)), intermediate-density lipoprotein (IDL), HDL subclasses (HDL2 and HDL3), LDL subclasses (LDL1, LDL2, LDL3, and LDL4), VLDL subclasses (VLDL1, VLDL2, and VLDL3), and LDL maximum time, which is directly proportional to LDL size. Because VAP measures additional lipoprotein classes, such as Lp(a), IDL, and subclasses of HDL, LDL, and VLDL, it can identify patients at high risk for coronary heart disease who cannot be identified using the standard lipid panel. In addition, the VAP method is compliant with the National Cholesterol Education Program's Adult Treatment Panel III guidelines.

Diabetic dyslipidemia

Type 2 diabetes mellitus is associated with a markedly increased risk of cardiovascular disease. A complex dyslipidemia, which is an integral part of the underlying insulin resistance in this group, is a key to this increased risk. Increased secretion of VLDL from the liver is a central feature of dyslipidemia and is linked significantly to the low HDL and abnormal LDL that are also present. A number of physiologic and pharmacologic approaches are available and should be used aggressively to treat diabetic dyslipidemia.

n-3 fatty acids and the metabolic syndrome

The metabolic syndrome is defined as the coexistence of 3 or more components, some of which indicate alterations in glucose and lipid metabolism. The prevalence of the metabolic syndrome is rapidly increasing in relation to obesity, and it is considered to be an important predictor of cardiovascular disease. Increased intakes or supplements of n-3 marine fatty acids may improve defects in insulin signaling and prevent alterations in glucose homeostasis and the further development of type 2 diabetes. This is largely mediated through a reduction in fatty acid accumulation in muscle and liver. n-3 Polyunsaturated fatty acids (n-3 PUFAs) reduce plasma triacylglycerols and improve the lipoprotein profile by decreasing the fraction of atherogenic small, dense LDL. However, n-3 PUFAs do not lower LDL cholesterol. These effects are likely mediated through the activity of transcription factors relating to expression of genes involved in lipid oxidation and synthesis. Other pleiotrophic effects of n-3 PUFAs may contribute to decreasing the burden of the metabolic syndrome, such as modulating inflammation, platelet activation, endothelial function, and blood pressure. Although studies comparing the effect of both major n-3 PUFAs are limited, docosahexaenoic acid appears at least as efficient as eicosapentaenoic acid in correcting several risk factors. The use of n-3 PUFAs should be considered in more global strategies including changes in lifestyle, such as adhering to a healthy Mediterranean type of diet and practicing regular physical exercise.

Prevalence of Hyperlipidemia and Its Risk Factors for the Middle-Aged and Elderly in the Guangxi Hei Yi Zhuang and Han Populations

BACKGROUND

Han is the largest and Zhuang is the second largest among the 56 nationalities in China. Geographically and linguistically, Zhuang can be classified into 43 ethnic subgroups, among which Hei Yi (which means "black worship" and "black dressing") Zhuang is the most conservative group, according to its unique culture and customs. Little is known about the lipid profiles and corresponding risk factors of hyperlipidemia in this population. Therefore, the aim of this study was to compare the effects of demographic characteristics, health-related behaviors, and lifestyle factors on the prevalence of hyperlipidemia for the middle-aged and elderly in the Guangxi Hei Yi Zhuang and Han populations.

METHODS

A sample of 657 people of Hei Yi Zhuang aged 40 years and over was randomly selected from 7 villages in Napo County, Guangxi, China. Information on demographic characteristics, health-related behaviors, and lifestyle factors was collected by questionnaire. Blood pressure, height, weight, waist circumference, and serum lipid and apolipoprotein (apo) levels were measured, and body mass index (BMI) was calculated as a measure of weight relative to height. The results were compared with those in 520 people of Han living in the same region.

RESULTS

The prevalence of hyperlipidemia in the Hei Yi Zhuang was significantly lower than that in the Han (36.2% vs 42.3%; p < .05). The levels of total cholesterol, triglyceride, low-density lipoprotein cholesterol, and apo B in Hei Yi Zhuang were also significantly lower than those in the Han (p < .05 to .001), but the levels of high-density lipoprotein cholesterol and the ratio of apo A-I to apo B in the Hei Yi Zhuang were significantly higher than those in the Han (p < .01 and < .001, respectively). There were no significant differences in apo A-I levels between the two ethnic groups (p > .05). The prevalence of hyperlipidemia was positively correlated with BMI and blood pressure in the Hei Yi Zhuang. Hyperlipidemia was positively associated with age, BMI, and blood pressure and negatively associated with gender (female higher) in the Han.

CONCLUSIONS

In the present study of the middle-aged and elderly population, the Hei Yi Zhuang have a more favorable lipid profile and a lower prevalence of hyperlipidemia than do the Han, and there is also a significant difference in the risk factors for hyperlipidemia between the two ethnic groups, which might result from the effects of different demographic characteristics, health-related behaviors, and lifestyle factors.