sdLDL-C Levels Research Articles

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.

Serum concentration of small dense low-density lipoprotein-cholesterol during oral glucose tolerance test and oral fat tolerance test

BackgroundSmall dense low-density lipoprotein (sdLDL) is well known as an atherogenic lipoprotein. We developed a new assay to measure serum concentration of sdLDL-cholesterol (sdLDLC). Using this assay, we reported a unique circadian rhythm of sdLDLC. We determined whether a glucose intake and/or a fat intake affects on serum sdLDLC concentration and determined the modulators of serum sdLDLC concentration. MethodsTen healthy volunteers were recruited to perform both a 75 g oral glucose tolerance test (OGTT) and an oral fat tolerance test (OFTT) to determine the effects of glucose and fat ingestion separately. Blood was measured for sdLDLC concentration and other valuables. ResultsSerum concentrations of total cholesterol, LDLC, remnant-like particles-cholesterol (RLPC), and apolipoprotein B significantly decreased during OGTT (p<0.05). SdLDLC also decreased and was a minimum at 2 h after glucose ingestion and increased to the baseline by 3 h. The sdLDLC decrease was seen while serum insulin level was high. The change of sdLDLC during OGTT had greater inverse correlationship with that of serum insulin level (r=−0.74, p<0.01) than that of plasma glucose level (r=−0.69, p=0.04). After fat ingestion, triglyceride and RLPC increased remarkably (p<0.01) but sdLDLC, LDLC, apolipoprotein B, and insulin did not change significantly. ConclusionsSerum concentration of sdLDLC was not affected by a fat intake but by a glucose intake. The change of sdLDLC was associated by that of serum insulin level, suggesting that insulin can be one of the key modulator of serum sdLDLC level as well as LDL metabolism.

The effect of orlistat and fenofibrate, alone or in combination, on small dense LDL and lipoprotein-associated phospholipase A 2 in obese patients with metabolic syndrome

Background Increased concentration of small dense LDL cholesterol (sdLDL-C) and activity of lipoprotein-associated phospholipase A2 (Lp-PLA 2) are considered as emerging cardiovascular risk factors and are commonly encountered in subjects with metabolic syndrome (MetS). Objective The primary endpoint of this study was the effect of orlistat and fenofibrate, alone or in combination, on Lp-PLA 2 activity and LDL phenotype in overweight and obese patients (body mass index > 28 kg/m 2) with MetS. Methods Patients ( n = 89) were prescribed a low-fat low-calorie diet and were randomly allocated to receive orlistat 120 mg three times daily (O group), micronized fenofibrate 200 mg/day (F group) or both (OF group) for 6 months. Results Significant reductions of sdLDL-C levels were observed in all treatment groups. Groups F and OF experienced a greater reduction in sdLDL-C levels ( p < 0.05) together with a greater increase in LDL particle diameter ( p < 0.05) compared with group O. Total plasma Lp-PLA 2 activity significantly decreased in all treatment groups. The reduction of Lp-PLA 2 was more pronounced with OF administration compared with each monotherapy ( p < 0.05). Conclusion Orlistat and fenofibrate exhibited favorable effects on Lp-PLA 2 activity and LDL phenotype in overweight and obese patients with MetS. Importantly, combination treatment had a more favorable effect on these risk factors.

The hypertriglyceridemic waist phenotype is a predictor of elevated levels of small, dense LDL cholesterol

The hypertriglyceridemic waist (HTGW) phenotype (hypertriglyceridemia and increased waist circumference) has been proposed as an inexpensive tool to monitor individuals with the atherogenic metabolic triad, hyperinsulinemia, hyperapobetalipoproteinemia, and increased levels of small, dense LDL (sdLDL) particles. We assessed the association of the HTGW phenotype with the metabolic syndrome (MetSyn) and the atherogenic metabolic triad in inhabitants (n = 260) of northwestern Greece attending the Outpatient Lipid Clinic of the University Hospital of Ioannina. The LDL subfractions were assessed using the Lipoprint LDL System. HTGW (+) individuals had a more adverse lipid and lipoprotein profile compared with HTGW (-) individuals. Moreover, HTGW (+) subjects had elevated levels of sdLDL-C, as well as decreased mean and peak LDL particle size compared with HTGW (-) subjects. To our knowledge, this is the first report documenting the sdLDL-C abnormality in HTGW (+) subjects. Among men (n = 105), 52.3% of the MetSyn (+) individuals and 66.7% of the HTGW (+) individuals had the metabolic triad. Among women (n = 155), the corresponding percentages were 42.3% and 50.0%. Only 22.2% and 10.6% of the MetSyn (-) subjects (men and women, respectively) and 19.6% and 15.2% of the HTGW (-) subjects (men and women, respectively) had the atherogenic metabolic triad. In conclusion, the HTGW (+) phenotype is associated with a hostile lipid profile that includes higher levels of sdLDL-C and decreased LDL particle size. The HTGW phenotype, compared with the MetSyn criteria, can provide an easy and inexpensive tool to monitor patients characterized by an adverse lipid and lipoprotein profile.