Dense Low-density Lipoprotein Cholesterol Concentration Research Articles

Accuracy of Small Dense Low-density Lipoprotein-cholesterol Concentration Estimated via Sampson's Equation in Healthy Subjects and Patients with Diabetes.

Sampson et al. proposed a method to calculate small dense low-density lipoprotein-cholesterol (sdLDL-C) concentrations using common lipid measurements, but its accuracy remains unresolved. We examined the difference between Sampson's equation and direct measurement in patients with diabetes. sdLDL-C was measured directly by our established homogeneous assay and estimated by Sampson's equation in patients with diabetes (n=1542) and healthy control subjects (n=673). Large-buoyant (lb)LDL-C was estimated using triglycerides and LDL-C, and sdLDL-C was obtained by subtracting lbLDL-C from LDL-C. The effect of fasting/nonfasting state or lipid-lowering drug therapy on sdLDL-C values was also examined in 30 and 43 patients with diabetes, respectively. The coefficient of determination (R 2 ) between calculated sdLDL-C and direct measurement was 0.73 and 0.61 for healthy controls and patients with diabetes, respectively. The R2 between calculated sdLDL-C and nonHDL-C or apolipoprotein B was 0.64 and 0.65, respectively. Calculated sdLDL-C was 4-5 mg/dl or 17%-18% higher than the direct measurement. The lower the plasma lipids, especially sdLDL-C, the greater the dissociation between the two methods. Sampson sdLDL-C was also found to give a positive bias when calculated for the nonfasting samples. Statins and pemafibrate significantly reduced sdLDL-C, but their therapeutic effect was underestimated by 5 mg/dl (24%) via Sampson's equation. The correlation between Sampson's equation and direct measurements of sdLDL-C was reduced in patients with diabetes. Furthermore, the correlations with nonHDL-C and apolipoprotein B were even higher than those with direct sdLDL-C. The accuracy of Sampson's equation decreased with lower sdLDL-C concentrations and was also influenced by diet.

Validation of Estimated Small Dense Low-Density Lipoprotein Cholesterol Concentration in a Japanese General Population.

A high level of directly measured small dense low-density lipoprotein cholesterol (sdLDL-C) is a strong risk factor for atherosclerotic cardiovascular disease. A method for estimating sdLDL-C by using Sampson's equation that includes levels of total cholesterol, high-density lipoprotein cholesterol (HDL-C), non-HDL-C and triglycerides (TG) has recently been proposed. We investigated the validation and exploration of estimated sdLDL-C level. The associations between measured and estimated sdLDL-C levels were investigated in 605 Japanese subjects (men/women: 280/325; mean age: 65±15 years) who received annual health check-ups in the Tanno-Sobetsu Study, a population-based cohort. Estimated sdLDL-C level was highly correlated with measured sdLDL-C level in all subjects (R2=0.701), nondiabetic subjects without any medication (n=254, R2=0.686) and subjects with diabetes mellitus (n=128, R2=0.721). Multivariable regression analysis showed that levels of non-HDL-C, TG and γ-glutamyl transpeptidase (γGTP) were independent predictors of measured sdLDL-C level. In a stratification of the LDL window, all of the subjects with a combination of high non-HDL-C (≥ 170 mg/dL) and high TG (≥ 150 mg/dL) had high levels of measured and estimated sdLDL-C (≥ 35 mg/dL). Furthermore, machine learning-based estimation of sdLDL-C level by artificial intelligence software, Prediction One, was substantially improved by using components of Sampson's equation (R2=0.803) and by using those components with the addition of γGTP and deletion of TC (R2=0.929). sdLDL-C level estimated by Sampson's equation can be used instead of measured sdLDL-C level in general practice. By building multiple machine learning models of artificial intelligence, a more accurate and practical estimation of sdLDL-C level might be possible.

Positive Association Between Small Dense Low-Density Lipoprotein Cholesterol Concentration and Biomarkers of Inflammation, Thrombosis, and Prediabetes in Non-Diabetic Adults.

Aims: Recent studies suggest elevated levels of small dense low-density lipoprotein cholesterol (sdLDL-C) can predict the risk of incident coronary heart disease (CHD), even in individuals considered to be at low risk for cardiovascular disease(CVD) based on their LDL-C levels. This study aims to prospectively investigate the association between sdLDL-C concentration and traditional and nontraditional CHD risk markers to explore the underlying roles of sdLDL-C in atherogenic processes.Methods: Between 2009 and 2011, 594 healthy volunteers aged 35–65 years were recruited as control subjects in a study of work-related risk factors and acute CHD. All participants fasted for 12–14 h, and venous blood samples were collected in the morning to measure serum lipid profiles and other CHD-related markers. A standard oral glucose tolerance test was performed on all participants to assess their subclinical diabetes and prediabetes status.Results: There were significantly positive associations between sdLDL-C concentration and traditional (age, smoking and alcohol drinking habit, blood pressure, body mass index (BMI), serum lipid profiles, and diabetes status) and nontraditional risk factors (complete blood counts, (CBC), fibrinogen, high-sensitivity C-reactive protein, and subclinical diabetes status) for CVD. After adjusting for confounding variables which include age, gender, BMI, hypertension, household income, and smoking and alcohol drinking habits, all atherosclerotic risk markers except D-dimer were significantly and positively associated with sdLDL-C.Conclusions: Our data indicated sdLDL-C is strongly associated with atherosclerotic risk markers, such as inflammation, thrombosis, hematological markers, and prediabetes. This study supports the hypothesis that sdLDL-C is a promising CVD risk biomarker.

Positive association between small dense low-density lipoprotein cholesterol concentration and biomarkers of inflammation, thrombosis, and prediabetes in non-diabetic adults

Positive association between small dense low-density lipoprotein cholesterol concentration and biomarkers of inflammation, thrombosis, and prediabetes in non-diabetic adults

Phytosterols, Phytostanols, and Lipoprotein Metabolism

The efficacy of phytosterols and phytostanols added to foods and food supplements to obtain significant non-pharmacologic serum and low density lipoprotein (LDL) cholesterol reduction is well documented. Irrespective of age, gender, ethnic background, body weight, background diet, or the cause of hypercholesterolemia and, even added to statin treatment, phytosterols and phytostanols at 2 g/day significantly lower LDL cholesterol concentration by 8%–10%. They do not affect the concentrations of high density lipoprotein cholesterol, lipoprotein (a) or serum proprotein convertase subtilisin/kexin type 9. In some studies, phytosterols and phytostanols have modestly reduced serum triglyceride levels especially in subjects with slightly increased baseline concentrations. Phytosterols and phytostanols lower LDL cholesterol by displacing cholesterol from mixed micelles in the small intestine so that cholesterol absorption is partially inhibited. Cholesterol absorption and synthesis have been carefully evaluated during phytosterol and phytostanol supplementation. However, only a few lipoprotein kinetic studies have been performed, and they revealed that LDL apoprotein B-100 transport rate was reduced. LDL particle size was unchanged, but small dense LDL cholesterol concentration was reduced. In subjects with metabolic syndrome and moderate hypertriglyceridemia, phytostanols reduced not only non- high density lipoprotein (HDL) cholesterol concentration but also serum triglycerides by 27%, and reduced the large and medium size very low density lipoprotein particle concentrations. In the few postprandial studies, the postprandial lipoproteins were reduced, but detailed studies with apoprotein B-48 are lacking. In conclusion, more kinetic studies are required to obtain a more complete understanding of the fasting and postprandial lipoprotein metabolism caused by phytosterols and phytostanols. It seems obvious, however, that the most atherogenic lipoprotein particles will be diminished.

Relationship between carotid artery intima-media thickness and small dense low-density lipoprotein cholesterol concentrations measured by homogenous assay in Japanese subjects

BackgroundSmall dense low-density lipoprotein cholesterol (sdLDL-C) concentrations correlate more strongly with coronary heart disease than other LDL-C and large LDL particle concentrations. We investigated the association between carotid artery intima-media thickness (IMT) and sdLDL-C concentrations in Japanese subjects. MethodsCarotid artery IMT, blood pressure (BP), fasting plasma sdLDL-C, glucose metabolism, lipid, and C-reactive protein concentrations were measured in 97 native Japanese subjects. Carotid artery IMT was assessed by ultrasonography, and sdLDL-C concentrations were measured by a homogenous assay. Pearson's correlation coefficient analyses and multiple regression analyses were used to examine the relationships between carotid artery IMT values, sdLDL-C values, and other clinical variables. ResultsAfter multiple regression analysis, including age, sex, body mass index, systolic BP, diastolic BP, fasting plasma glucose, HbA1c, estimated glomerular filtration rate (eGFR), total-C, high-density lipoprotein (HDL)-C, triglyceride, LDL-C, non-HDL-C, large buoyant LDL-C, and sdLDL-C, carotid artery IMT remained significantly associated with age, systolic BP, diastolic BP, and sdLDL-C, whereas sdLDL-C remained significantly associated with age, total-C, HDL-C, triglycerides, and carotid artery IMT. ConclusionsWhen measured by a homogenous assay, carotid artery IMT may have a closer relationship with sdLDL-C concentrations than other lipid parameters in Japanese subjects. sdLDL-C may be a potentially useful risk marker when assessing carotid artery IMT in Japanese subjects.

Small dense low-density lipoprotein cholesterol concentration and carotid atherosclerosis

Low-density lipoprotein cholesterol (LDL-C) and the small dense LDL (SdLDL) phenotype are both predictors for ischemic heart disease. We examined whether cholesterol of SdLDL (SdLDL-C) is more closely associated with carotid artery intima-media thickness (CA-IMT), a surrogate measure of atherosclerosis, than LDL-C and other lipid parameters. The subjects were 326 consecutive participants including those with dyslipidemia, diabetes mellitus, hypertension, chronic kidney disease, and smokers. SdLDL-C was quantified by a newly developed precipitation method, and CA-IMT by high-resolution B-mode ultrasound. In univariate analysis, CA-IMT was most strongly correlated with SdLDL-C (Spearman's r = 0.441, P < 0.001), followed by apolipoprotein (apo) B, LDL-C, non-high-density lipoprotein cholesterol (Non-HDL-C), and plasma triglycerides (TG). HDL-C and apo A-I correlated inversely with CA-IMT. Non-lipid variables that were associated with CA-IMT were age, sex, presence of diabetes mellitus, presence of hypertension, estimate glomerular filtration rate (eGFR), and C-reactive protein (CRP). Even after adjustment for age, sex, diabetes mellitus, hypertension, smoking, eGFR and CRP, the positive association of CA-IMT with SdLDL-C remained significant, and again stronger than the associations with others lipid parameters. Further analyses revealed that the level of SdLDL-C was elevated in subgroups of the subjects including men, older subjects, smokers, those with higher CRP levels, those with diabetes mellitus, and hypertensive patients. These results indicate that SdLDL-C was the best marker of carotid atherosclerosis among the lipid parameters tested, and suggest that quantitative measurement of SdLDL-C gives useful information in the risk assessment for atherosclerotic disease.

Effects of Increasing Doses of Atorvastatin on the Atherogenic Lipid Subclasses Commonly Associated With Hypertriglyceridemia

The increased cardiovascular risk associated with hypertriglyceridemia is thought to be due in part to high levels of triglyceride (TG)-rich lipoproteins and small dense low-density lipoprotein (LDL). In this post hoc analysis, effects of increasing doses of atorvastatin (10, 20, 40, and 80 mg) on atherogenic lipid subclasses commonly associated with hypertriglyceridemia were evaluated in 191 men and women who were candidates for lipid-lowering therapy and had baseline TG levels >200 mg/dl (2.3 mmol/L). After 8 weeks of treatment, in addition to significantly decreasing LDL cholesterol and TG levels, atorvastatin significantly increased LDL peak particle diameter (p <0.01) and significantly decreased the concentration of small LDL subclasses IIIa and IIIb (p <0.0001) from baseline at all doses. These effects were more pronounced with higher compared with lower doses of atorvastatin. Each dose of atorvastatin also significantly lowered levels of very LDL, intermediate-density lipoprotein (p <0.0001), and small very LDL subclass 3 (p <0.0001). Greater decreases were achieved by those patients receiving higher doses of atorvastatin (20, 40, and 80 mg). The increase in LDL size correlated with the decrease in TG levels, but not with the decrease in LDL cholesterol levels. However, the decrease in small dense LDL cholesterol concentrations correlated significantly with TG and LDL cholesterol decreases. In conclusion, atorvastatin significantly lowered levels of TG-rich remnant lipoproteins and favorably changed LDL particle size in patients with hypertriglyceridemia. These effects may explain the benefits of statin therapy in high-risk patients with hypertriglyceridemia even when levels of LDL cholesterol are at goal.

Elevated Small Dense Low-density Lipoprotein Cholesterol Concentration as a Promising Risk Marker for Severe Stable Coronary Heart Disease, Independently of Adiponectin and C-reactive Protein

Elevated Small Dense Low-density Lipoprotein Cholesterol Concentration as a Promising Risk Marker for Severe Stable Coronary Heart Disease, Independently of Adiponectin and C-reactive Protein

Significance of small dense low-density lipoprotein-cholesterol concentrations in relation to the severity of coronary heart diseases

We have investigated the clinical significance of small dense low-density lipoprotein-cholesterol (sd-LDL-C) concentrations in coronary heart disease (CHD). We measured the LDL size by gradient gel electrophoresis and quantified sd-LDL-C concentrations by a newly developed rapid assay using heparin–magnesium precipitation in 225 consecutive CHD patients without any lipid-lowering medication and 142 healthy middle-aged subjects as controls. The LDL size was markedly smaller and sd-LDL-C levels were significantly higher in CHD patients than in controls of both sexes, whereas LDL-C levels were comparable between CHD and controls. The LDL-C levels were significantly higher in a subpopulation of 84 patients with acute coronary syndrome than in other patients groups, while LDL size and high-density lipoprotein-cholesterol (HDL-C) were not found to vary among the patients. The sd-LDL-C increased as the number of diseased vessels or Gensini atherosclerosis score increased. Among the 123 stable CHD patients, multiple logistic regression analysis revealed that sd-LDL-C levels were significantly associated with the clinically severe cases requiring coronary revascularization independently of LDL-C, HDL-C and apolipoprotein B. The sd-LDL mass plays a more important role in the progression of CHD than the LDL size, and the sd-LDL-C concentration serves as a powerful surrogate marker for the prevention of CHD.

CRP—Marker or Maker of Cardiovascular Disease?

C-reactive protein (CRP) has emerged as an interesting novel and potentially clinically useful marker for increased cardiovascular risk.1,2 This is an attractive concept because atherosclerosis is a disease characterized by chronic arterial inflammation3,4 and suggests the possibility that subclinical states of atherosclerosis can be identified by an increase in circulating markers of inflammation before acute events occur. Based on data obtained primarily from in vitro studies it has also been proposed that CRP in itself is actively contributing to disease progression and that it should be considered as true risk factor and consequently as a target for intervention. However, in the present issue of Arteriosclerosis, Thrombosis, and Vascular Biology , two independent reports demonstrate that transgenic overexpression of CRP does not affect the development of atherosclerosis in mice, suggesting that this is not the case. See pages 1635 and 1641 The association between moderately elevated CRP levels and an increased risk for development of cardiovascular disease is well established. Although the increase in risk may have been overestimated in initial studies, recent meta-analysis comprising >7000 patients with coronary events shows that subjects with CRP in the upper tertile have a 50% increased risk for development of acute cardiovascular events.2 There are several possible explanations for this association (Figure). (1) The inflammatory process in arterial tissue affected by atherosclerosis results in release of cytokines into the circulation that subsequently activates expression of CRP in the liver. Plasma CRP levels would then reflect the severity of atherosclerosis and, as a consequence, the risk for development of clinical events. If CRP in addition …