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

Evaluation of measured and calculated small dense low-density lipoprotein in capillary blood and association with the metabolic syndrome

BACKGROUND AND AIMS

Small-dense-low-density-lipoprotein cholesterol (sdLDL-C) is proatherogenic and not commonly measured. The aims were to evaluate capillary blood and its stability for sdLDL-C measurement and measure sdLDL-C in patients with metabolic syndrome (MS).

METHODS

182 patients were studied (49 with MS). sdLDL-C was measured by electrophoresis (LipoPrint®), direct measurement (Roche Diagnostics) and Sampson equation. Intima-media thickness (IMT) and presence of atheroma was evaluated. sdLDL-C was compared in paired venous and capillary blood according to CLSI-EP09c (n = 40). sdLDL-C stability was studied after 24 h at room temperature (RT).

RESULTS

sdLDL-C in capillary blood and venous blood showed agreement with the direct measurement (bias: 4.17 mg/dL, LOA 95 %:-5.66; 13.99) and estimation (bias:8.12 mg/dL, LOA 95 %:-8.59; 24.82). sdLDL-C is stable in capillary blood for 24 h at RT. The electrophoretic method yielded lower (p < 0.05) sdLDL-C than the equation or direct measurement. Patients with MS had (p < 0.05) higher sdLDL-C (%) than patients without MS. Patients with atheroma plaques had higher sdLDL-C (p < 0.05). Estimated sdLDL-C correlated with IMT (r = 0.259, p < 0.001).

CONCLUSIONS

Capillary blood is an alternative to venous blood for sdLDL-C measurement and is stable for 24 h after collection. Estimated and directly measured sdLDL-C associate with the MS being accessible tools for cardiovascular risk assessment.

Small Dense LDL: Scientific Background, Clinical Relevance, and Recent Evidence Still a Risk Even with ‘Normal’ LDL-C Levels

Residual cardiovascular disease event risk, following statin use and low-density lipoprotein cholesterol (LDL-C) reduction, remains an important and common medical conundrum. Identifying patients with significant residual risk, despite statin drug use, is an unmet clinical need. One pathophysiologic disorder that contributes to residual risk is abnormal distribution in lipoprotein size and density, which is referred to as lipoprotein heterogeneity. Differences in low density lipoprotein (LDL) composition and size have been linked to coronary heart disease (CHD) risk and arteriographic disease progression. The clinical relevance has been investigated in numerous trials since the 1950s. Despite this long history, controversy remains regarding the clinical utility of LDL heterogeneity measurement. Recent clinical trial evidence reinforces the relevance of LDL heterogeneity measurement and the impact on CHD risk prediction and outcomes. The determination of LDL subclass distribution improves CHD risk prediction and guides appropriate treatment.

Serum folate modified the association between low-density lipoprotein cholesterol and carotid intima-media thickness in Chinese hypertensive adults

BACKGROUND AND AIMS

While folate is known for its importance in cardiovascular health, it is unknown whether folate status can modify the association between low-density lipoprotein cholesterol (LDL-C) and carotid intima-media thickness (CIMT). We aimed to investigate this question in a Chinese hypertensive population, who are at high-risk of low folate and atherosclerosis.

METHODS AND RESULTS

This report included 14,970 hypertensive adults (mean age 64.5 years; 40.3% male) from the China Stroke Primary Prevention Trial (CSPPT) and analyzed the fasting serum LDL-C and folate, and CIMT data obtained at the last follow-up visit. LDL-C was calculated using the Friedewald equation. Serum folate levels were measured by chemiluminescent immunoassay. CIMT was measured by ultrasound. Non-parametric smoothing plots, multivariate linear regression analysis, subgroup analyses and interaction testing were performed to examine the LDL-C-CIMI relationship and effect modification by folate. Consistent with graphic plots, multivariate linear regression showed that LDL-C levels were independently and positively associated with CIMT (β = 7.69, 95%CI: 5.76-9.62). More importantly, the relationship between LDL-C and CIMT was significantly attenuated with increasing serum folate levels (1st tertile: β = 10.06, 95%CI: 6.67-13.46; 2nd tertile: β = 6.81, 95%CI: 3.55-10.07; 3rd tertile: β = 5.96, 95%CI: 2.55-9.36; P-interaction = 0.045). Subgroup analyses showed the association between LDL-C and CIMT across serum folate tertiles was robust among various strata (all P-interaction >0.05).

CONCLUSIONS

Among Chinese hypertensive adults, the serum folate levels could modify the association between LDL-C and CIMT. Our findings, if further confirmed, have important clinical implications.

Association of small dense LDL-cholesterol with disease severity, hypertension status and clinical outcome in patients with coronary artery disease

OBJECTIVE

Previous studies have demonstrated that small dense LDL-cholesterol (sdLDL-C) is related to the pathogenesis of coronary artery disease (CAD). However, its prognostic role in hypertensive patients with CAD has been undetermined. The aim of the study was to investigate the association between sdLDL-C with disease severity, hypertensive status and clinical outcome in patients with CAD.

METHODS

A total of 4594 patients with angiography-proven CAD were consecutively enrolled and categorized into subgroups according to blood pressure status. Serum sdLDL-C levels were measured by direct quantitative measurement using automated chemistry analyzers. The severity of coronary artery lesions were determined by Gensini score, Syntax score and the number of lesion vessels. The associations of sdLDL-C with disease severity, hypertensive status and cardiovascular events (CVEs) were evaluated.

RESULTS

Patients with hypertension had higher sdLDL-C levels than ones without (P = 0.010). In hypertensive patients, sdLDL-C was positively associated with the severity of CAD (P < 0.05). In addition, hypertensive patients with poorly controlled hypertension had higher sdLDL-C levels than those with well controlled (P < 0.05). Moreover, 149 CVEs occurred in patients with poorly controlled hypertension and Cox regression analysis indicated that elevated sdLDL-C levels were independently associated with CVEs in hypertensive patients with poorly controlled hypertension (adjusted hazard ratio: 1.673, 95% confidence interval: 1.105-2.535, P = 0.015).

CONCLUSION

The current data, for the first time, showed that serum sdLDL-C levels were correlated with hypertension control, disease severity and worse outcomes in hypertensive patients with CAD, suggesting that paying more attention on sdLDL-C in these patients were warranted.

Small Dense Low-Density Lipoprotein Cholesterol and Carotid Intimal Medial Thickness Progression

AIM

The association between small dense low-density lipoprotein cholesterol (sdLDL-C) levels and carotid intimal medial thickness (cIMT) progression has not been evaluated fully. We assessed specialized lipoproteins, including sdLDL-C, with regard to cIMT progression in a prospective observational study in Japan.

METHODS

Plasma total cholesterol, direct LDL-C, sdLDL-C, LDL-triglycerides (LDL-TG), high-density lipoprotein cholesterol (HDL-C), HDL2-C, HDL3-C, triglycerides, Lp(a), and adiponectin were measured in 2,030 men and women (median age 59 years, free of cardiovascular disease (CVD) and off cholesterol lowering medication). At both baseline and after a five-year follow-up, cIMT was assessed. Univariate, multivariate regression, and least square analyses were performed to examine the relationships between direct LDL-C, sdLDL-C, and other lipoproteins with cIMT progression.

RESULTS

The median cIMT at baseline was 0.63 mm and five-year progression was 0.18 mm. After adjustment for standard CVD risk factors, including age, gender, systolic blood pressure, total cholesterol, HDL-C, smoking, diabetes, and hypertension treatment, only direct LDL-C, sdLDL-C, and the sdLDL-C/LDL-C ratio were associated with cIMT progression. Even in subjects with direct LDL-C ＜100 mg/dL, who were considered at low CVD risk, elevated sdLDL-C were associated with cIMT progression (P for trend=0.009) in a model with established CVD risk factors, although the sdLDL-C/LDL-C ratio did not. Those correlations did not change by including triglycerides as a controlling factor or excluding premenopausal women from the analyzed population.

CONCLUSIONS

Small dense LDL-C has a stronger relationship with cIMT progression than LDL-C does; therefore, measuring sdLDL-C may allow for the formulation of optimal therapy for CVD prevention.

High sdLDL Cholesterol can be Used to Reclassify Individuals with Low Cardiovascular Risk for Early Intervention: Findings from the Chinese Multi-Provincial Cohort Study

Aim: A high-risk strategy has been implemented for lipid-lowering therapy in the primary prevention of cardiovascular disease. However, atherosclerosis and cardiovascular events are common among individuals with low cardiovascular risk. This study aimed to determine whether the small dense low-density lipoprotein cholesterol (sdLDLC) level can predict carotid atherosclerosis progression and identify high-risk individuals.

Methods: Baseline sdLDLC and low-density lipoprotein cholesterol (LDLC) were measured in 808 particip ants from the Chinese Multi-provincial Cohort Study, aged 45–74 years. Adjusted relative risk was calculated using a modified Poisson regression model to assess the relationship between sdLDLC and 5-year atherosclerosis progression, as indicated by the progression, incidence, and multi-territorial extent of carotid plaque.

Results: The 5-year atherosclerosis progression increased significantly with increased sdLDLC. Baseline sdLDLC was significantly associated with the short-term risk of plaque progression after multivariable adjustment, even in participants with low LDLC or a 10-year estimated cardiovascular risk. sdLDLC predicted plaque progression (relative risk 2.05; 95% confidence interval 1.43–2.93) in participants with LDLC < 130 mg/dL. Furthermore, participants with the highest sdLDLC but intermediate or low cardiovascular risk (accounting for 16% of the cohort) had double the risk of plaque progression, which was comparable to those with the same sdLDLC and high cardiovascular risk, relative to those with the lowest sdLDLC levels and low cardiovascular risk.

Conclusions: sdLDLC is independently associated with the progression of carotid atherosclerosis, which may provide a basis for clinicians to reclassify individuals believed to be at low cardiovascular risk into the high-risk category, and those with high sdLDLC may benefit from more aggressive cholesterol-lowering treatment.

Small, dense LDL: an update

PURPOSE OF REVIEW

In this review, we summarize the latest findings on small, dense LDL (sdLDL) atherogenic particles, including their associations with other biomarkers.

RECENT FINDINGS

Increased sdLDL levels have been reported not only in different metabolic disorders such as diabetes, obesity and metabolic syndrome, but also in patients with rheumatoid and psoriatic arthritis as well as hypothyroidism. A wide range of lipid-lowering, as well as other drug classes, including novel antidiabetic agents and nutraceuticals, exert favourable effects on these atherogenic particles. The 'gold standard' methodology for the assessment of sdLDL has not been established yet. However, the association between sdLDL and several biomarkers could facilitate their assessment.

SUMMARY

Estimation of sdLDL in daily clinical practice may help with the identification of patients at high cardiovascular risk and further contribute in directing specific interventions to prevent and/or decrease such risk.

Low-density lipoprotein-associated variables and the severity of coronary artery disease: an untreated Chinese cohort study

BACKGROUND AND AIMS

Elevated low-density lipoprotein cholesterol (LDL-C) is causal risk for coronary artery disease (CAD) and LDL-associated variables including LDL-C, apolipoprotein B (apoB), non-high-density lipoprotein cholesterol (non-HDL-C), lipoprotein a [Lp(a)], small dense LDL (sd-LDL), and oxidized LDL (ox-LDL) have been widely used for predicting the risk of CAD. This study was aimed to compare the values of six LDL-related variables for predicting the severity of CAD using untreated patients undergoing coronary angiography (CAG).

METHODS

A group of 1977 individuals were consecutively enrolled and divided into CAD (n = 1151) and non-CAD groups (n = 826) according to the results of CAG. LDL-C, apoB, non-HDL-C, Lp(a), sd-LDL and ox-LDL were measured, respectively. The numbers of stenotic arteries and Gensini Scores (GS) were used to calculate the severity of CAD and the associations of six variables with the severity of CAD and predicting value of these parameters were simultaneously examined.

RESULTS

CAD patients had significantly higher concentrations of LDL-related variables than non-CAD ones (all p < 0.05). Importantly, all variables rose with the increase in the severity of CAD. The predicting value of CAD manifested as sd-LDL > ox-LDL > apoB > non-HDL-C > LDL-C > Lp(a) [area under curve (AUC): sd-LDL 0.641; ox-LDL 0.640; apoB 0.611; non-HDL-C 0.587; LDL-C 0.583; Lp(a) 0.554; respectively]. In multivariate logistic analysis, all variables showed as independent risk factors for the severity of CAD [odds ratio (OR): ox-LDL > sd-LDL > apoB > non-HDL-C > LDL-C > Lp(a)].

CONCLUSIONS

All of LDL-related variables could be useful marker for predicting the severity of CAD but sd-LDL and ox-LDL appeared to litter better. Further study may be needed to validate our results.

Lipid and lipoprotein abnormalities in acute lymphoblastic leukemia survivors

Survivors of acute lymphoblastic leukemia (ALL), the most common cancer in children, are at increased risk of developing late cardiometabolic conditions. However, the mechanisms are not fully understood. This study aimed to characterize the plasma lipid profile, Apo distribution, and lipoprotein composition of 80 childhood ALL survivors compared with 22 healthy controls. Our results show that, despite their young age, 50% of the ALL survivors displayed dyslipidemia, characterized by increased plasma triglyceride (TG) and LDL-cholesterol, as well as decreased HDL-cholesterol. ALL survivors exhibited lower plasma Apo A-I and higher Apo B-100 and C-II levels, along with elevated Apo C-II/C-III and B-100/A-I ratios. VLDL fractions of dyslipidemic ALL survivors contained more TG, free cholesterol, and phospholipid moieties, but less protein. Differences in Apo content were found between ALL survivors and controls for all lipoprotein fractions except HDL₃ HDL₂, especially, showed reduced Apo A-I and raised Apo A-II, leading to a depressed Apo A-I/A-II ratio. Analysis of VLDL-Apo Cs disclosed a trend for higher Apo C-III₁ content in dyslipidemic ALL survivors. In conclusion, this thorough investigation demonstrates a high prevalence of dyslipidemia in ALL survivors, while highlighting significant abnormalities in their plasma lipid profile and lipoprotein composition. Special attention must, therefore, be paid to these subjects given the atherosclerotic potency of lipid and lipoprotein disorders.

Nanoparticle uptake by macrophages in vulnerable plaques for atherosclerosis diagnosis

The composition of atherosclerotic (AS) plaques is crucial concerning rupture, thrombosis and clinical events. Two plaque types are distinguished: stable and vulnerable plaques. Vulnerable plaques are rich in inflammatory cells, mostly only M1 macrophages, and are highly susceptible to rupture. These plaques represent a high risk particularly with the standard invasive diagnosis by coronary angiography. So far there are no non-invasive low-risk clinical approaches available to detect and distinguish AS plaque types in vivo. The perspective review introduces a whole work-flow for a novel approach for non-invasive detection and classification of AS plaques using the diffusion reflection method with gold nanoparticle loaded macrophages in combination with flow and image cytometric analysis for quality assurance. Classical biophotonic methods for AS diagnosis are summarized. Phenotyping of monocytes and macrophages are discussed for specific subset labelling by nanomaterials, as well as existing studies and first experimental proofs of concept for the novel approach are shown. In vitro and in vivo detection of NP loaded macrophages (MΦ). Different ways of MΦ labelling include (1) in vitro labelling in suspension (whole blood or buffy coat) or (2) labelling of short-term MΦ cultures with re-injection of MΦ-NP into the animal to detect migration of the cells in the plaques and (3) in vivo injection of NP into the organism.

Correlation between small dense low-density lipoprotein cholesterol and carotid artery intima-media thickness in a healthy Chinese population

BACKGROUND

Small dense low-density lipoprotein cholesterol (sdLDL-C) concentration was useful in the assessment of the presence of cardiovascular diseases (CVD) and its severity. We examined whether SdLDL-C is more closely associated with carotid artery intima-media thickness (CA-IMT), a surrogate measure of atherosclerosis, than LDL-C and traditional CVD risk factors in Chinese healthy subjects.

METHODS

We measured CA-IMT, blood pressure (BP), sdLDL-C, glucose metabolism and lipid in 183 native Chinese healthy subjects. CA-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 CA-IMT values and other clinical variables.

RESULTS

The sdLDL-C level was significantly higher in males than in females (p <0.05) and there was an age effect on sdLDL-C (p <0.05). When the effects of age, gender and other traditional CVD risk factors were adjusted using multiple regression analysis. CA-IMT remained significantly associated with sdLDL-C(β = 0.437, p <0.001).

CONCLUSIONS

There are gender and age differences in sdLDL-C levels among a healthy Chinese population. Moreover, we found adjusted traditional CVD risk factors such as higher age, male sex, and other traditional CVD risk factors, the association between CA-IMT and SdLDL-C remained significant. sdLDL-C is may be a useful predictor in the assessment of CA-IMT in Chinese population.

Circulating non-HDL-C levels were more relevant to atherogenic lipoprotein subfractions compared with LDL-C in patients with stable coronary artery disease

BACKGROUND

Conflicting results have been yielded as to whether low-density lipoprotein (LDL) cholesterol (LDL-C) or non-high-density lipoprotein (HDL) cholesterol (non-HDL-C) is a better marker of coronary artery disease (CAD) risk. Recently, plasma LDL and HDL subfractions have been suggested to be more accurately reflecting the lipoproteins' atherogenicity.

OBJECTIVE

We sought to compare the relationship between LDL-C or non-HDL-C and lipoprotein subfractions.

METHODS

We conducted a cross-sectional study in 351 consecutive stable CAD patients without lipid-lowering therapy. The LDL and HDL separations were performed using the Lipoprint System. The LDL-C levels were measured directly, and the non-HDL-C levels were calculated.

RESULTS

The cholesterol concentrations of LDL (large, medium, and small) and HDL (small) particles were increased (all P < .001) by non-HDL-C or LDL-C quartiles, whereas the mean LDL particle size and cholesterol concentrations of HDL (large) were decreased (both P < .001) by non-HDL-C quartiles. In age- and gender-adjusted analysis, the cholesterol in small LDL was much strongly related to non-HDL-C than to LDL-C (r = 0.539 vs 0.397, both P < .001). Meanwhile, the mean LDL particle size was more closely associated with non-HDL-C than LDL-C (r = -0.336 vs r = -0.136, both P < .05). Significantly, the cholesterol in large HDL was negatively correlated with non-HDL-C (r = -0223, P < .001) but not with LDL-C. These correlations were further confirmed by the fully adjusted multivariable linear regression analysis.

CONCLUSIONS

Non-HDL-C, in comparison to LDL-C, was more relevant to atherogenic lipoprotein subfractions in patients with stable CAD, supporting that it may be better in assessing cardiovascular risk.

High Fiber Caribbean Diets with Low-Intermediate GI Improve Glycemic Control, Cardiovascular and Inflammatory Indicators in Overweight Persons with Type 2 Diabetes: A Randomized Control Study

This study focused on the effect of consumption of indigenous Caribbean foods with low and intermediate glycemic index (GI) high fiber contents on glycated haemoglobin (A1c), insulin, fasting blood glucose, homocysteine (tHCY), high sensitivity C-reactive protein (hs-CRP), HOMA-IR and lipoprotein profile levels in overweight persons with type 2 diabetes. The methodology followed a randomized controlled parallel design, which compared two dietary treatment modalities in adult Jamaicans who were overweight and diagnosed with type 2 diabetes (mean age 42.5 ± 2.0 years, 55% females, mean A1c 9.30 ± 0.56%) over six months. The intervention group (n=32) underlined the consumption of low-intermediate-GI foods, whereas the control group (n = 33) were not so advised and consumed a high-GI diet. Attempts were made to ensure that both groups were isocaloric with 45-50% of energy from carbohydrates. Consumption of low-intermediate GI foods resulted in significant reductions (p<0.005) in A1C compared to participants who consumed high GI foods (-0.84 ± 0.26 vs. -0.35 ± 0.04%), hs-CRP (-0.52 ± 0.17 vs. -0.17 ± 0.31 mg/dL) and tHCY (-1.32 ± 0.39 vs. -0.59 ± 0.38 µmol/L). Insulin sensitivity, HDL-C and triglycerides significantly improved in participants who consumed the low-intermediate-GI diet. The data strengthen the metabolic benefits of meal plans that emphasize the consumption of low and intermediate GI high fiber foods, particularly, indigenous Caribbean complex starchy foods.