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

Impact of Direct Measurement of Small Dense Low-Density Lipoprotein Cholesterol for Long-Term Secondary Prevention in Patients with Stable Coronary Artery Disease

BACKGROUND

This study investigated whether directly measured small dense low-density lipoprotein cholesterol (D-sdLDL-C) can predict long-term coronary artery disease (CAD) events compared with low-density lipoprotein cholesterol (LDL-C), non-high-density lipoprotein cholesterol (non-HDL-C), apolipoprotein B (apoB), and estimated small dense low-density lipoprotein cholesterol (E-sdLDL-C) determined by the Sampson equation in patients with stable CAD.

METHODS

D-sdLDL-C measured at Showa University between 2010 and 2022, and E-sdLDL-C were evaluated in 790 male and 244 female patients with stable CAD. CAD events, defined as sudden cardiac death, onset of acute coronary syndrome, and/or need for coronary revascularization, were monitored for 12 years. Cutoff lipid levels were determined by receiver operating characteristic curves.

RESULTS

CAD events were observed in 238 male and 67 female patients. The Kaplan-Meier event-free survival curves showed that patients with D-sdLDL-C ≥32.1 mg/dL (0.83 mmol/L) had an increased risk for CAD events (P = 0.007), whereas risk in patients with E-sdLDL-C ≥36.2 mg/dL (0.94 mmol/L) was not increased. In the group with high D-sdLDL-C, the multivariable-adjusted hazard ratio (HR) was 1.47 (95% CI, 1.15-1.89), and it remained significant after adjustment for LDL-C, non-HDL-C, or apoB and in patients treated with statins. HRs for high LDL-C, non-HDL-C, or apoB were not statistically significant after adjustment for high D-sdLDL-C. Higher D-sdLDL-C was associated with enhanced risk of high LDL-C, non-HDL-C, and apoB (HR 1.73; 95% CI, 1.27-2.37).

CONCLUSIONS

Higher D-sdLDL-C can predict long-term recurrence of CAD in stable CAD patients independently of apoB and non-HDL-C. D-sdLDL-C is an independent risk enhancer for secondary CAD prevention, whereas E-sdLDL-C is not. UMIN-CTR Clinical Trial Number: UMIN000027504.

The association of Sort1 expression with LDL subfraction and inflammation in patients with coronary artery disease

BACKGROUND

Controversial effect of sortilin on lipoprotein metabolism in the development of atherosclerosis reveals the need for more extensive research.

OBJECTIVES

The aim of this study was to investigate the association between Sort1 gene expression and lipids, lipoprotein subfractions, and inflammation in CAD.

METHODS

The study population included 162 subjects with CAD and 49 healthy individuals. The Sort1 gene expression level was determined by qRT-PCR using Human Sortilin TaqMan Gene Expression Assays. Lipoprotein subclasses were analysed by the Lipoprint system. Serum levels of apolipoprotein and CRP were measured by autoanalyzer.

RESULTS

Sort1 gene expression and atherogenic subfraction (SdLDL) levels were significantly higher (p < 0.001) while atheroprotective subfraction (LbLDL) was lower in the subjects with CAD (p < 0.050). Also, increased Sort1 gene expression levels were observed in those with higher CRP values.

CONCLUSIONS

Our findings reveal that the high Sort1 gene expression has a prominent linear relationship with both the atherogenic LDL phenotype and proinflammation, thereby might contribute to the occurrence of CAD.

Small Dense Low-Density Lipoprotein Cholesterol Levels in Breakfast Skippers and Staple Foods Skippers

AIMS

Skipping breakfast is known as a cardiovascular disease (CVD) risk. Recently, eating and dietary patterns have been varied in many countries, however, the mechanisms of promoting CVD are still unclear. Our goal was to assess the effects of eating and dietary patterns on CVD risk factors, with a focus on lipid parameters including serum concentration of small dense low-density lipoprotein cholesterol (sdLDL-C).

METHODS

Subjects consisted of 27,997 Japanese men and women, who had medical check-up. Lipid parameters including sdLDL-C levels in breakfast skippers were compared with those in breakfast eaters. Lipid parameters in staple foods skippers were also compared with those in staple foods eaters.

RESULTS

Breakfast skippers had significantly (p＜0.01) higher serum levels of median sdLDL-C than breakfast eaters in both genders (34.7 versus 32.0 mg/dL in men, 25.4 versus 24.9 mg/dL in women, respectively), and the same was true for sdLDL-C/LDL-C ratio (0.276 versus 0.260 in men, 0.218 versus 0.209 in women, respectively). Similarly, staple foods skippers had significantly higher sdLDL-C level than staple foods eaters in both genders (34.1 versus 31.6 mg/dL in men, 25.8 versus 24.7 mg/dL in women), and the same went for sdLDL-C/LDL-C ratio (0.278 versus 0.256 in men, 0.215 versus 0.208 mg/dL in women, respectively).

CONCLUSION

Our data indicate that both skipping breakfast and having meals without staple foods increase serum sdLDL-C concentration and cause unfavorable lipid profiles, and then may promote CVD. These finding provide evidence for the importance of having breakfast and meals with staple foods for preventing CVD.

Association of Lipoprotein Subfractions With Presence and Severity of Coronary Artery Disease in Patients Referred for Coronary Angiography

Lipoprotein subfractions (LS) can be used for better risk stratification in subjects deemed not at high risk for coronary artery disease (CAD). In this study, we evaluated the correlation between LS with CAD presence and severity. This is a prospective case-control study of 157 patients referred for coronary angiography who were not on lipid-lowering therapy and had LS measured by nuclear magnetic resonance spectroscopy. Synergy between PCI with Taxus and Cardiac Surgery (SYNTAX) scores were calculated to estimate CAD severity. Univariate and multivariable regression analysis was performed to determine correlation of LS with CAD presence and severity and acute coronary syndrome (ACS). There was significant association of certain LS (positive for total low-density lipoprotein particle [LDL-P], small LDL-P and apolipoprotein B, negative for large high-density lipoprotein particle [HDL-P] and apolipoprotein A1 [ApoA1]) with the presence of obstructive CAD and CAD severity. Small LDL-P and HDL-P were still predictive for obstructive CAD after adjusting for traditional risk factors, 10-year atherosclerotic cardiovascular disease risk score and in those with low-density lipoprotein cholesterol <100 mg/100 ml. Total LDL-P and ApoA1 were predictive of CAD severity on multivariable analysis. Higher small LDL-P and lower large HDL-P were associated with ACS presence, although only large HDL-P had a significant inverse correlation with ACS on adjusted analysis (odds ratio 0.74 95% confidence interval 0.58, 0.95) In conclusion, in our cohort of patients referred for coronary angiography, total LDL-P, small LDL-P, and apolipoprotein B had significant direct correlation, and large HDL-P and ApoA1 had significant inverse correlation with obstructive CAD and CAD severity.

The LDL-C/Apo B predicts coronary atherosclerotic heart disease in non-diabetic patients without high LDL-C

The apolipoprotein B (Apo B), Apo B/A1 ratio, lipoprotein (a), and low-density lipoprotein cholesterol (LDL-C)/Apo B ratio are associated with coronary artery disease (CAD). However, the association between these parameters and CAD in non-diabetic patients without high LDL-C levels is unclear. Our goal was to assess which parameter was most strongly associated with CAD in non-diabetic patients without high LDL-C levels. This study included 487 non-diabetic patients with LDL-C < 130.0 mg/dL. All the patients underwent coronary computed tomographic angiography. We assessed the significance of each continuous atherogenic biomarker for CAD (incidence of coronary plaque and revascularization) without and after adjustment for standard risk factors. The LDL-C/Apo B ratio and lipoprotein (a) were significant risk factors for the incidence of coronary plaque on multivariate analysis after adjustment for standard risk factors. The LDL-C/Apo B ratio was significant for the incidence of revascularization in multivariate analysis after adjustment for standard risk factors. The degree of coronary calcification and plaque burden according to the tertile of LDL-C/Apo B showed significant differences between the groups. Our data indicate that LDL-C/Apo B ratio is the most predictive parameter for coronary atherosclerosis in non-diabetic patients without high LDL-C levels.

Small Dense Low-Density Lipoprotein Level in Newly Diagnosed Type 2 Diabetes Mellitus Patients With Normal Low-Density Lipoprotein

Background and objective There are three subtypes of low-density lipoprotein (LDL): large buoyant (lb), intermediate, and small dense (sd). Among these LDL subtypes, small dense low-density lipoprotein (sdLDL) has been proven to be an independent risk factor for atherosclerosis. Type 2 diabetes mellitus (T2DM) encompasses several metabolic abnormalities and patients suffering from T2DM without good glycemic control are prone to develop atherosclerosis. Hence, in T2DM, it is recommended to evaluate blood lipids for early detection of hyperlipidemia to identify the risk. A larger percentage of sdLDL in T2DM patients with an optimal or near-optimal LDL level might be a hidden risk factor for atherosclerosis. Hence, we aimed to find the level of sdLDL cholesterol (sdLDL-C) among newly diagnosed T2DM patients with optimal or near-optimal blood lipids and to compare it with age and sex-matched controls. Materials and methods In this study, we enrolled newly diagnosed T2DM patients from the diabetic clinic of a tertiary care hospital. The patients were then tested for blood lipids, namely, total cholesterol, triglyceride, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol (LDL-C), including sdLDL-C. Then, age and sex-matched controls with similar baseline lipid levels to the T2DM group (without sdLDL-C) were recruited. After recruitment, both groups were measured for blood lipids including sdLDL-C in a single day. The level of sdLDL-C between the groups was tested statistically by the Mann-Whitney U test. Results A total of 50 T2DM patients with a median age of 36 years (Q1-Q3: 33.75-41) were included as the study group and 50 age and sex-matched controls with a median age of 34 years (32-37.25; p = 0.09) were recruited. The median fasting glucose was 165 (Q1-Q3: 145-199.25) mg/dL and 90.5 (Q1-Q3: 87.75-95.25) mg/dL (p < 0.0001) in the study and control groups, respectively. The LDL-C was 109.9 (Q1-Q3: 99.4-119.4) mg/dL and 108.5 (Q1-Q3: 87.55-124.1) mg/dL (p = 0.94) in the study and control groups, respectively. The sdLDL-C was 40.11 (Q1-Q3: 36.28-43.58) mg/dL and 24.64 (Q1-Q3: 22-32.49) mg/dL (p < 0.0001) in the study and control groups, respectively. Conclusion Newly diagnosed T2DM patients with blood lipids within an optimum or near-optimum level may have a higher percentage of sdLDL-C when compared with healthy controls. Hence, they may have a higher risk of atherosclerosis and cardiovascular diseases. Clinicians may miss the potential risks if they do not advise the sdLDL-C component of LDL-C while advising for the test for blood lipid.

Atherogenic Lipoproteins for the Statin Residual Cardiovascular Disease Risk

Randomized controlled trials (RCTs) show that decreases in low-density lipoprotein cholesterol (LDL-C) by the use of statins cause a significant reduction in the development of cardiovascular disease (CVD). However, one of our previous studies showed that, among eight RCTs that investigated the effect of statins vs. a placebo on CVD development, 56–79% of patients had residual CVD risk after the trials. In three RCTs that investigated the effect of a high dose vs. a usual dose of statins on CVD development, 78–87% of patients in the high-dose statin arms still had residual CVD risk. The risk of CVD development remains even when statins are used to strongly reduce LDL-C, and this type of risk is now regarded as statin residual CVD risk. Our study shows that elevated triglyceride (TG) levels, reduced high-density lipoprotein cholesterol (HDL-C), and the existence of obesity/insulin resistance and diabetes may be important metabolic factors that determine statin residual CVD risk. Here, we discuss atherogenic lipoproteins that were not investigated in such RCTs, such as lipoprotein (a) (Lp(a)), remnant lipoproteins, malondialdehyde-modified LDL (MDA-LDL), and small-dense LDL (Sd-LDL). Lp(a) is under strong genetic control by apolipoprotein (a), which is an LPA gene locus. Variations in the LPA gene account for 91% of the variability in the plasma concentration of Lp(a). A meta-analysis showed that genetic variations at the LPA locus are associated with CVD events during statin therapy, independent of the extent of LDL lowering, providing support for exploring strategies targeting circulating concentrations of Lp(a) to reduce CVD events in patients receiving statins. Remnant lipoproteins and small-dense LDL are highly associated with high TG levels, low HDL-C, and obesity/insulin resistance. MDA-LDL is a representative form of oxidized LDL and plays important roles in the formation and development of the primary lesions of atherosclerosis. MDA-LDL levels were higher in CVD patients and diabetic patients than in the control subjects. Furthermore, we demonstrated the atherogenic properties of such lipoproteins and their association with CVD as well as therapeutic approaches.

Causal effects of genetically predicted type 2 diabetes mellitus on blood lipid profiles and concentration of particle-size-determined lipoprotein subclasses: A two-sample Mendelian randomization study

Background

Observational studies have shown inconsistent results of the associations between type 2 diabetes mellitus (T2DM) and blood lipid profiles, while there is also a lack of evidence from randomized controlled trials (RCTs) for the causal effects of T2DM on blood lipid profiles and lipoprotein subclasses.

Objectives

Our study aimed at investigating the causal effects of T2DM on blood lipid profiles and concentration of particle-size-determined lipoprotein subclasses by using the two-sample Mendelian randomization (MR) method.

Methods

We obtained genetic variants for T2DM and blood lipid profiles including high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides (TG), and total cholesterol (TC) from international genome-wide association studies (GWASs). Two-sample MR method was applied to explore the potential causal effects of genetically predicted T2DM on blood lipid profiles based on different databases, respectively, and results from each MR analysis were further meta-analyzed to obtain the summary results. The causal effects of genetically predicted T2DM on the concentration of different subclasses of lipoproteins that are determined by particle size were also involved in MR analysis.

Results

Genetically predicted 1-unit higher log odds of T2DM had a significant causal effect on a higher level of TG (estimated β coefficient: 0.03, 95% confidence interval [CI]: 0.00 to 0.06) and lower level of HDL-C (estimated β coefficient: −0.09, 95% CI: −0.11 to −0.06). The causality of T2DM on the level of TC or LDL-C was not found (estimated β coefficient: −0.01, 95% CI: −0.02 to 0.01 for TC and estimated β coefficient: 0.01, 95% CI: −0.01 to 0.02 for LDL-C). For different sizes of lipoprotein particles, 1-unit higher log odds of T2DM was causally associated with higher level of small LDL particles, and lower level of medium HDL particles, large HDL particles, and very large HDL particles.

Conclusion

Evidence from our present study showed causal effects of T2DM on the level of TG, HDL-C, and concentration of different particle sizes of lipoprotein subclasses comprehensively, which might be particularly helpful in illustrating dyslipidemia experienced by patients with T2DM, and further indicate new treatment targets for these patients to prevent subsequent excessive cardiovascular events from a genetic point of view.

Association between small dense LDL levels and hepatic fibrosis in patients with nonalcoholic fatty liver disease

While patients with nonalcoholic fatty liver disease (NAFLD) continue to increase worldwide, few hematological biomarkers are helpful. This study examined the potential of small dense low density lipoprotein (sdLDL) as a noninvasive biomarker for NAFLD and investigated the relevance of liver fibrosis. One hundred seventy two patients were enrolled: 121 NAFLD patients and 51 healthy controls. The lipoprotein profiles of NAFLD patients and controls were analyzed, and transient elastography (Fibroscan®) was performed to evaluate the degree of NAFLD. The liver biopsy results in some NAFLD patients were also analyzed. Age-gender matching was performed among the 172 patients, and a comparison with 46 NAFLD patients with the control group confirmed that the sdLDL (P < .001) is significantly higher in the NAFLD group. A liver fibrosis test performed on 121 NAFLD patients confirmed a positive correlation between the degree of hepatic fibrosis and the sdLDL/LDL ratio (R = 0.215, P = .017). The area under the curve of the sdLDL for the diagnosis of NAFLD was 0.734 (95% CI, 0.631-0.838), and the area under the curve of the sdLDL/LDL ratio was 0.730 (95% CI, 0.621-0.829). The sdLDL and NAFLD activity scores of the 11 NAFLD patients who underwent liver biopsy showed a positive correlation, but it was not statistically significant. The sdLDL was higher in NAFLD patients than in controls and showed a tendency to increase gradually with increasing degree of hepatic steatosis and fibrosis. In particular, the sdLDL/LDL ratio showed a significant correlation with the degree of hepatic fibrosis, and the sdLDL measurement could be useful in NAFLD patients.

Reference interval for serum concentration of small dense low-density lipoprotein cholesterol in the healthy Japanese population

BACKGROUND

Small dense low-density lipoprotein a smaller and denser subfraction among whole low density lipoprotein particles is known to be highly atherogenic. The reference interval (RI) is not strictly defined for serum concentration of sdLDL-cholesterol (sdLDL-C) in Japan. The purpose of this study is to set the reference interval for sdLDL-C in healthy subjects.

METHODS

The population of this cross-sectional study was consisted of 40,862 individuals who had annual health checkups, and healthy subjects were extracted based on exclusion criteria such as medical history, social history, and blood sampling test results. Their serum sdLDL-C values were statistically analyzed and the RIs were set in men, premenopausal women, and postmenopausal women separately.

RESULTS

The mean values of serum sdLDL-C in healthy subjects were 23.9 mg/dL in men, 20.0 mg/dL in premenopausal women and 23.7 mg/dL in postmenopausal women, and the RIs were 12.6-45.3 mg/dL in men, 11.4-35.1 mg/dL in premenopausal women and 14.6-38.6 mg/dL in postmenopausal women. Serum sdLDL-C values were significantly higher in men than in women. Besides, sdLDL-C values were significantly higher in postmenopausal women than in premenopausal women. In both genders, sdLDL-C values tended to increase with age.

CONCLUSION

These results suggest that the RIs for sdLDL-C are recommended as follows: 13-45 mg/dL in men, 11-35 mg/dL in premenopausal women, and 15-39 mg/dL in postmenopausal women, respectively. Aside from these RIs, it is also necessary to define clinical cutoff values graded according to individual risk levels for atherosclerotic cardiovascular diseases.

Small Dense Low-Density Lipoprotein for Risk Prediction of Acute Coronary Syndrome

Background

Elevated Low density Lipoprotein (LDL) levels have been traditionally associated with development of atherosclerotic coronary artery disease (CAD). As LDL-cholesterol levels are not always raised in acute coronary syndrome (ACS) patients, sd-LDL is an emerging risk factor. The purpose of the present study was tri-fold. Firstly, it aimed to investigate the association of sd-LDL as a risk factor in ACS patients. Secondly, it aimed to correlate the presence of sd-LDL with severity of coronary artery disease as determined by coronary angiography. Lastly, it aimed to correlate the presence of sd-LDL with short-term outcomes.

Methods

This was a prospective, hospital-based, cross-sectional, case-control study conducted over a 1-year study duration. Patients above the age of 18 years diagnosed with ACS within 24 h of admission were studied. Blood samples were collected after all patients had undergone coronary angiography and sd-LDL levels were measured.

Results

ACS patients had significantly higher sd-LDL levels than non-ACS patients (16.10 ± 1.42 mg/dL vs. 12.67 ± 0.71 mg/dL, P = 0.036). Males had significantly higher sd-LDL levels than females (16.79 ± 1.55 mg/dl vs. 10.77 ± 2.62 mg/dl, P=0.047). Patients with non-left anterior descending coronary artery (LAD) involvement had significantly higher sd-LDL levels compared to patients with LAD involvement (21.92 ± 3.55 mg/dL vs. 14.03 ± 1.35 mg/dL, P = 0.007).

Conclusion

These results suggest that sd-LDL is a risk factor for the development of ACS in an Indian population.

Association between testosterone and lipid profiles under statin therapy and its clinical impact on the cardiovascular event risk

Statin therapy may decrease the levels of serum steroid hormones, including testosterone and cortisol, accompanied by lowering low-density lipoprotein cholesterol (LDL-C) levels, which remains to be investigated. The aim of this study is to examine the association between steroid hormones and lipids under statin therapy and its clinical impact on the cardiovascular event risk from a viewpoint of steroid hormone metabolism. Using a population dataset extracted from the standard versus intEnsive statin therapy for hyper-cholesteroleMic Patients with diAbetic retinopaTHY (EMPATHY) study, we analyzed the correlation between steroid hormones and lipid profiles at registration and 1 year after registration, comparing between male patients with or without cardiovascular events (CV events) within 4 years (CV events + ; n = 100, and CV events - ; n = 100, respectively) after prognostic score matching. The risk for CV events was evaluated using conditional logistic regression analysis. Testosterone levels were lower in the CV events + group than in the CV events - group at registration (5.2 ± 2.2 vs. 7.6 ± 4.1 ng/mL, p < 0.001). Testosterone levels were lowered to 5.1 ng/mL on average in proportion with LDL-C lowering, and Δtestosterone was correlated with ΔLDL-C during 1 year after registration. Cortisol levels were not correlated with LDL-C levels. In addition, testosterone levels at 1 year after registration were not associated with cardiovascular event risk. In male hypercholesterolemic patients with diabetic retinopathy, testosterone levels were positively correlated with LDL-C levels, which were mildly lowered in proportion with LDL-C lowering under mild statin therapy. This decrease in testosterone levels under statin therapy was not related to the increase in cardiovascular event risk.Clinical trial registration: UMIN 000003486. https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000004199.

Small Dense Low-Density Lipoprotein Cholesterol: A Residual Risk for Rapid Progression of Non-Culprit Coronary Lesion in Patients with Acute Coronary Syndrome

Aim: This study investigated whether the small dense low-density lipoprotein cholesterol (sd-LDL-c) level is associated with the rapid progression (RP) of non-culprit coronary artery lesions and cardiovascular events (CE) after acute coronary syndrome (ACS).

Methods: In 142 consecutive patients with ACS who underwent primary percutaneous coronary intervention for the culprit lesion, the sd-LDL-c level was measured using a direct homogeneous assay on admission for ACS and at the 10-month follow-up coronary angiography. RP was defined as a progression of any pre-existing coronary stenosis and/or stenosis development in the initially normal coronary artery. CEs were defined as cardiac death, myocardial infarction, stroke, or coronary revascularization.

Results: Patients were divided into two groups based on the presence ( n =29) or absence ( n =113) of RP after 10 months. The LDL-c and sd-LDL-c levels at baseline were equivalent in both the groups. However, the sd-LDL-c, triglyceride, remnant lipoprotein cholesterol (RL-c), and apoC3 levels at follow-up were significantly higher in the RP group than in the non-RP group. The optimal threshold values of sd-LDL-c, triglyceride, RL-c, and apoC3 for predicting RP according to receiver operating characteristics analysis were 20.9, 113, 5.5, and 9.7 mg/dL, respectively. Only the sd-LDL-c level (≥ 20.9 mg/dL) was significantly associated with incident CEs at 31±17 months (log-rank: 4.123, p =0.043).

Conclusions: The sd-LDL-c level on treatment was significantly associated with RP of non-culprit lesions, resulting in CEs in ACS patients. On-treatment sd-LDL-c is a residual risk and aggressive reduction of sd-LDL-c might be needed to prevent CEs.

Estimation of the LDL subclasses in ischemic stroke as a risk factor in a Chinese population

Background

Acute ischemic stroke (AIS) is one of the leading causes of mortality and long-term disability worldwide. Our study aims to clarify the role of low-density lipoproteins (LDL) subclasses in the occurrence of AIS and develop a risk xprediction model based on these characteristics to identify high-risk people.

Methods

Five hundred and sixty-six patients with AIS and 197 non-AIS controls were included in this study. Serum lipids and other baseline characteristics including fasting blood glucose (GLU), serum creatinine (Scr), and blood pressure were investigated in relation to occurrence of AIS. The LDL subfractions were classified and measured with the Lipoprint System by a polyacrylamide gel electrophoresis technique.

Results

Levels of LDL-3, LDL-4 and LDL-5 subclasses were significantly higher in the AIS group compared to the non-AIS group and lower level of LDL-1 was prevalent in the AIS patients. Consistently, Spearman correlation coefficient demonstrated that sd-demonevels, especially LDL-3 and LDL-4 levels, were significantly positively correlated with AIS. Furthermore, there is a significant positive correlation between small dense LDL (sd-LDL, that is LDL-3 to 7) levels and serum lipids including total cholesterol (TC), Low density lipoprotein cholesterol (LDL-C), and Triglyceride (TG). Increased LDL-3 and LDL-4 as well as decreased LDL-1 and LDL-2 were correlated to the occurrence of AIS, even in the people with normal LDL-C levels. A new prediction model including 12 variables can accurately predict the AIS risk in Chinese patients (AUC = 0.82 ± 0.04).

Conclusions

Levels of LDL subclasses should be considered in addition to serum LDL-C in assessment and management of AIS. A new prediction model based on clinical variables including LDL subtractions can help clinicians identify high of AIS, even in the people with norm.

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.

Evolocumab Effects on Lipoproteins, Measured by High-Performance Liquid Chromatography

AIMS

Profiling of lipoproteins can predict risk of cardiovascular disease; gel permeation high-performance liquid chromatography (HPLC) improves prediction accuracy by providing detailed data for specific lipoprotein subclasses. This study applied HPLC to examine the effects of evolocumab, which effectively treats hyperlipidemia and mixed dyslipidemia, on lipoprotein subclasses, specifically the number and size of lipoprotein particles.

METHODS

This post-hoc analysis used patient blood samples from YUKAWA-2, a phase 3 trial evaluating the efficacy of evolocumab in Japanese adult patients with hyperlipidemia or mixed dyslipidemia and at high risk for cardiovascular disease. We used HPLC to assess observed values and percent change from baseline in cholesterol and triglyceride (TG) concentrations, number of particles in lipoprotein subclasses to week 12, and mean observed values and mean percent change from baseline in variables to weeks 10 and 12. HPLC was also compared with conventional methods in assessing low-density lipoprotein (LDL) cholesterol (LDL-C) values.

RESULTS

Data for all 404 patients were analyzed. Evolocumab significantly decreased cholesterol and TG concentrations, and total particle count, in very low-density lipoprotein (VLDL) and LDL subclasses. Particle size increased slightly in LDL, high-density lipoprotein (HDL), and VLDL, but data varied widely. At very low LDL-C, HPLC measurements were higher than those from conventional methods.

CONCLUSION

This research used HPLC to assess the effects of evolocumab in 20 lipid subclasses. By lowering lipid content and improving the lipid profile, evolocumab may reduce atherogenicity. This reduction is better quantified by HPLC than by conventional methods in the very low LDL-C range.

Correlation between the small dense LDL level and nonalcoholic fatty liver disease: Possibility of a new biomarker

Small dense low-density lipoprotein (sdLDL) is a distinct low-density lipoprotein (LDL) cholesterol subclass that has been reported to be associated with metabolic disease. On the other hand, the relationship between the sdLDL level and the nonalcoholic fatty liver disease (NAFLD) severity is unclear. In this study, the sdLDL level was measured in patients with NAFLD to assess its potential as a biomarker for evaluating NAFLD. One hundred and twenty-six patients diagnosed with NAFLD at a single referral hospital from January 2018 to August 2019 were enrolled. The lipoprotein profile was analyzed from a blood test of NAFLD patients, and transient elastography (TE, Fibroscan) was performed to evaluate the degree of NAFLD. Among the 126 patients, 83 patients that could confirm the lipoprotein profile and TE results were finally enrolled in the study. The controlled attenuation parameter (CAP) value obtained from TE did not show any correlation with the total cholesterol, LDL. But, the sdLDL level showed a significant positive correlation with the CAP value (r = 0.237, P = .031), and the sdLDL/LDL ratio also showed a significant positive correlation with the CAP value (r = 0.235, P = .032). The liver stiffness (LS) measured by TE and the sdLDL level were positively correlated in patients with NAFLD (rho = 0.217, P = .049). The sdLDL/LDL ratio also showed a significant positive correlation with the LS value (rho = 0.228, P = .038). In addition, the fatty liver index also showed a significant positive correlation with the sdLDL/LDL ratio (r = 0.448, P = .000). In this study, the sdLDL level measured by a blood test of NAFLD patients showed a positive correlation with the CAP value and LS, which indicate the degree of hepatic steatosis and fibrosis. These results suggest the possibility of the sdLDL level as a new biomarker of NAFLD, but further studies will be needed to support these results.

Association of small dense low-density lipoprotein with cardiovascular outcome in patients with coronary artery disease and diabetes: a prospective, observational cohort study

Background

Elevation in small dense low-density lipoprotein (sdLDL) is common in patients with diabetes mellitus (DM), which has already been reported to be associated with incidence of coronary artery disease (CAD). The aim of the present study was to investigate the prognostic value of plasma sdLDL level in patients with stable CAD and DM.

Methods

A total of 4148 consecutive patients with stable CAD were prospectively enrolled into the study and followed up for major cardiovascular events (MACEs) up to 8.5 years. Plasma sdLDL level was measured in each patient by a direct method using automated chemistry analyzer. The patients were subsequently divided into four groups by the quartiles of sdLDL and the association of sdLDL level with MACEs in different status of glucose metabolism [DM, Pre-DM, normal glycaemia regulation (NGR)] was evaluated.

Results

A total of 464 MACEs were documented. Both Kaplan–Meier analysis and Cox regression analysis indicated that the patients in quartile 4 but not quartile 2 or 3 of sdLDL level had significantly higher rate of MACEs than that in lowest quartile. When the prognostic value of high sdLDL was assessed in different glucose metabolism status, the results showed that the high sdLDL plus DM was associated with worse outcome after adjustment of confounding risk factors (hazard ratio: 1.83, 95% confident interval: 1.24–2.70, p < 0.05). However, no significant association was observed for high sdLDL plus Pre-DM or NGR.

Conclusions

The present study firstly indicated that elevated levels of plasma sdLDL were associated with increased risk of MACEs among DM patients with proven CAD, suggesting that sdLDL may be useful for CAD risk stratification in DM.

Eicosapentaenoic acid (EPA) has optimal chain length and degree of unsaturation to inhibit oxidation of small dense LDL and membrane cholesterol domains as compared to related fatty acids in vitro

BACKGROUND

Oxidation of small dense low-density lipoprotein (sdLDL) and membranes is causally related to atherosclerosis. The omega-3 fatty acid (FA) eicosapentaenoic acid (EPA, 20:5, ω-3) significantly reduced oxidized LDL in patients with hypertriglyceridemia by unknown mechanisms. We compared EPA effects to related FAs of varying chain length and unsaturation on oxidation of sdLDL and model membranes, and on cholesterol crystal domains. We compared EPA to the FAs: stearic (SA, 18:0), oleic (OA, 18:1, ω-9), linoleic (LA, 18:2, ω-6), alpha-linolenic (ALA, 18:3, ω-3), eicosanoic (EA, 20:0), eicosatrienoic (ETE, 20:3, ω-3), arachidonic (AA, 20:4, ω-6), docosapentaenoic (DPA, 22:5, ω-3), and docosahexaenoic (DHA, 22:6, ω-3).

METHODS

Human sdLDL or model membranes of cholesterol and 1,2-Dilinoleoyl-sn-glycero-3-phosphocholine [18:2(cis)PC or DLPC] were preincubated with FAs followed by copper-induced oxidation. Malondialdehyde (MDA) or lipid hydroperoxides (LOOH) levels measured oxidation; small-angle X-ray diffraction assessed cholesterol domain formation.

RESULTS

After 40 min, EPA reduced MDA levels 70% compared to vehicle (p < 0.001). Lesser inhibition was observed with DHA, DPA, ETE, and ALA (33%, 34%, 32%, and 16%, respectively; all p < 0.001 versus vehicle). Similar relative FA effects were observed in model membranes where EPA more substantially inhibited cholesterol crystal domain formation.

CONCLUSION

We observed relationships between hydrocarbon length and unsaturation with antioxidant activity and membrane cholesterol domain formation. EPA had the most favorable molecular structure, likely contributing to membrane stability, improved lipoprotein clearance, and reduced inflammation.

GENERAL SIGNIFICANCE

Insight is provided into FA hydrocarbon length and unsaturation relationships with antioxidant activity in lipoproteins and membranes, and cholesterol crystal domains formation.

Impact of obeticholic acid on the lipoprotein profile in patients with non-alcoholic steatohepatitis

BACKGROUND & AIMS

Obeticholic acid (OCA), a farnesoid X receptor agonist, increases total and low-density lipoprotein cholesterol (LDL-C) in patients with non-alcoholic steatohepatitis. In the present study, we aimed to evaluate the impact of OCA therapy on lipoprotein sub-particles.

METHOD

This study included 196 patients (99 OCA group and 97 placebo group) who were enrolled in the FLINT trial and had samples available for lipid analysis and liver biopsies at enrollment and end-of-treatment (EOT) at 72 weeks. Very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) particles were evaluated at baseline, 12 and 72 weeks after randomization, and 24 weeks following EOT.

RESULTS

Baseline lipoprotein profiles were similar among OCA and placebo groups. OCA did not affect total VLDL particle concentrations, but OCA vs. placebo treatment was associated with decreased large VLDL particle concentration at 12 weeks (baseline-adjusted mean: 6.8 vs. 8.9 nmol/L; p = 0.002), mirrored by an increase in less atherogenic, small VLDL particle concentration (33.9 vs. 28.0 nmol/L; p = 0.02). After 12 weeks, total LDL particle concentration was higher in the OCA group than the placebo group (1,667 vs. 1,329 nmol/L; p <0.0001), characterized by corresponding increases in both less atherogenic, large-buoyant LDL (475 vs. 308 nmol/L; p ≤0.001) and more atherogenic small-dense LDL particles (1,015 vs. 872 nmol/L; p = 0.002). The changes in LDL particle concentrations were similar between treatment groups (OCA and placebo) 24 weeks following EOT due to improvement in the OCA cohort. Compared to placebo, a reduction in total HDL particle concentration, particularly large and medium HDL particles, was noted in the OCA-treated patients, but this resolved after drug discontinuation.

CONCLUSION

OCA therapy is associated with increases in small VLDL particles, large and small LDL particles, and a reduction in HDL particles at 12 weeks. These lipoprotein concentrations reverted to baseline values 24 weeks after drug discontinuation.

LAY SUMMARY

Non-alcoholic steatohepatitis is a chronic liver disease that is associated with an increased risk of developing cirrhosis and cardiovascular disease. Recently, obeticholic acid (OCA), a farnesoid X receptor agonist, improved liver disease but led to an increase in cholesterol. However, the impact of OCA on cholesterol is not well understood. In the present study, we show that OCA therapy is associated with a detrimental increase in lipoprotein levels, which improves after drug discontinuation. ClinicalTrials.gov numbers: NCT01265498.

Non-HDL as a Valid Surrogate Marker of Small Dense LDL in a Young Indian Population

Small dense (sd) LDL is a significant independent risk factor for premature coronary artery disease (CAD). Unfortunately, its estimation is not popular, due to the limited availability of specialized equipment, high cost and time-consuming technique. Non-HDL is a calculated, single index measure of all atherogenic apolipoprotein-B containing lipoproteins. This study aimed at identifying non-HDL as a superior surrogate marker of sdLDL cholesterol in a young Indian population. 161 healthy subjects < 45 years were tested for lipid profile, apolipoproteins A1 and B, and sdLDL particle size. sdLDL particles showed negative correlation with non-HDL (r = - 0.283, p < 0.001), LDL (r = - 0.195, p = 0.013) and apoB/apo A1 (r = - 0.175, p = 0.026), the significance being greatest with non-HDL. ROC showed AUC for non-HDL, LDL and apoB/apo A1 as 0.704, 0.686, and 0.596 respectively. For LDL < 130 mg/dL, sdLDL showed a more significant negative correlation with non-HDL (r = - 0.291, p < 0.001) as compared with apoB/apoA1 (r = - 0.172, p = 0.037). For triglycerides < 200 mg/dL, sdLDL particle size showed higher significant negative correlation with non-HDL (r = - 0.213, p = 0.015) than with LDL (r = - 0.176, p = 0.045) while for triglycerides between 200 and 400 mg/dL, significant negative correlation was observed only with non-HDL (r = - 0.372, p = 0.043). Hence, our study suggested that non-HDL is a superior surrogate marker of sdLDL particle size as compared to LDL and apoB/A1 ratio in a young healthy Indian population and should be used for optimum assessment of dyslipidemias and CAD risk.

Small Dense Low-Density Lipoprotein Cholesterol Predicts Cardiovascular Events in Liver Transplant Recipients

Cardiovascular disease (CVD) is an important cause of morbidity and mortality after liver transplantation (LT). Although LT is associated with dyslipidemia, particularly atherogenic lipoprotein subparticles, the impact of these subparticles on CVD-related events is unknown. Therefore, the aim of the current study was to evaluate the impact of small dense (sdLDL-C) low-density lipoprotein (LDL) cholesterol (LDL-C) on CVD events. Prospectively enrolled patients (N = 130) had detailed lipid profile consisting of traditional lipid parameters and sdLDL-C and were followed for CVD events. The primary endpoint was a CVD composite consisting of myocardial infarction (MI), angina, need for coronary revascularization, and cardiac death. Mean age of the cohort was 58 ± 11 years, and the most common etiology of liver disease (LD) was hepatitis C virus (N = 48) and nonalcoholic steatohepatitis (N = 23). A total of 20 CVD events were noted after median follow-up of 45 months. The baseline traditional profile was similar in patients with and without CVD events. A serum LDL-C cutoff of 100 mg/dL was unable to identify individuals at risk of a CVD event (P = 0.86). In contrast, serum concentration of atherogenic sdLDL-C >25 mg/dL was predictive of CVD events with a hazard ratio of 6.376 (95% confidence interval, 2.65, 15.34; P < 0.001). This relationship was independent of diabetes, hypertension, sex, ethnicity, LD, obesity, and statin use. Conclusion: sdLDL-C independently predicted CVD events whereas LDL-C did not. Thus, sdLDL-C may provide a useful clinical tool in risk stratifying and managing patients after LT.

Elevated Triglycerides to High-Density Lipoprotein Cholesterol (TG/HDL-C) Ratio Predicts Long-Term Mortality in High-Risk Patients

BACKGROUND

Elevated triglycerides to high-density lipoprotein cholesterol (TG/HDL-C) ratio has been utilised as a predictor of outcomes in patients with adverse cardiometabolic risk profiles. In this study, we examined the prognostic value of elevated TG/HDL-C level in an Australian population of patients with high clinical suspicion of coronary artery disease (CAD) presenting for coronary angiography.

METHODS

Follow-up data was collected for 482 patients who underwent coronary angiography in a prospective cohort study. The primary endpoint was all-cause mortality and the secondary endpoint was a major adverse cardiac event (MACE). Patients were stratified into two groups according to their baseline TG/HDL-C ratio, using a TG/HDL-C ratio cut point of 2.5.

RESULTS

The mean follow-up period was 5.1 ± 1.2 years, with 49 all-cause deaths. Coronary artery disease on coronary angiography was more prevalent in patients with TG/HDL-C ratio ≥2.5 (83.6% vs. 69.4%, p = 0.03). On the Kaplan-Meier analysis, patients with TG/HDL-C ratio ≥2.5 had worse long-term prognosis (p = 0.04). On multivariate Cox regression adjusting for established cardiovascular risk factors and CAD on coronary angiography, TG/HDL-C ratio ≥2.5 was an independent predictor of long-term all-cause mortality (hazard ratio [HR] 2.10, 95% confidence interval [CI] 1.04-4.20, p = 0.04). On multivariate logistic regression adjusting for known cardiovascular risk factors and CAD on coronary angiography, TG/HDL-C ratio ≥2.5 was strongly associated with an increased risk of long-term MACE (odds ratio [OR] 2.72, 95% CI 1.42-5.20, p = 0.002).

CONCLUSIONS

Elevated TG/HDL-C ratio is an independent predictor of long-term all-cause mortality and is strongly associated with an increased risk of MACE.

New Insights into Mechanisms of Action for Omega-3 Fatty Acids in Atherothrombotic Cardiovascular Disease

PURPOSE OF REVIEW

Treatment of hypercholesterolemia with statins results in significant reductions in cardiovascular risk; however, individuals with well-controlled low-density lipoprotein cholesterol (LDL-C) levels, but persistent high triglycerides (TG), remain at increased risk. Genetic and epidemiologic studies have shown that elevated fasting TG levels are associated with incident cardiovascular events. At effective doses, omega-3 fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), lower TG levels but may have additional atheroprotective properties compared to other TG-lowering therapies such as niacin and fibrates. The purpose of this review is to evaluate mechanisms related to the potential benefits of omega-3 fatty acids in atherothrombotic disease.

RECENT FINDINGS

Large randomized clinical trials are currently under way to test the cardiovascular benefits of omega-3 fatty acids at a pharmacologic dosage (4 g/day). A large randomized trial with a prescription EPA-only formulation was shown to reduce a composite of cardiovascular events by 25% in statin-treated patients with established cardiovascular disease or diabetes and other CV risk factors. EPA and DHA have distinct tissue distributions as well as disparate effects on membrane structure and lipid dynamics, rates of lipid oxidation, and signal transduction pathways. Compared to other TG-lowering therapies, EPA has been found to inhibit cholesterol crystal formation, inflammation, and oxidative modification of atherogenic lipoprotein particles. The anti-inflammatory and endothelial benefits of EPA are enhanced in combination with a statin. Omega-3 fatty acids like EPA only at a pharmacologic dose reduce fasting TG and interfere with mechanisms of atherosclerosis that results in reduced cardiovascular events. Additional mechanistic trials will provide further insights into their role in reducing cardiovascular risk in subjects with well-managed LDL-C but elevated TG levels.

LDL Subclasses in Ischemic Stroke: A Risk Factor?

Introduction

Seven low-density lipoprotein (LDL) subclasses are identified, and smaller LDL particles are associated with an increased risk for cardiovascular events. However, there is limited data about the relationship between the acute ischemic stroke (AIS) subtypes and LDL subclasses. The aim of our study is to investigate the relationship between AIS subtypes and LDL subclasses.

Methods

This study consisted of 110 AIS patients and 60 healthy controls. Stroke patients were classified according to the TOAST classification system as cardioembolic infarct (CI), large artery atherosclerosis (LAA), and lacunar infarct (LI). LDL subclasses were distributed as seven bands (LDL-1 and-2 defined as large, and LDL-3 to-7 defined as small-LDL particle), using the LipoPrintª System. Control group and AIS subtypes were compared in terms of LDL subclasses; p<0.05 was considered statistically significant.

Results

AIS patients had higher LDL-2, LDL-3 and LDL-4 subclasses compared to the control groups, while LDL-1 was similar in two groups. In addition, LDL-2 and LDL-3 subclasses were significantly higher in each AIS subtype when compared to the control group. LDL-4 subclasses were significantly higher in LAA and LI subtypes than in the control group, but there was no relationship for CI subtypes. Smaller subclasses LDL-5 to LDL-7 were undetectable in both AIS patients and controls. Using regression analysis; age, LDL-2, LDL-3 and LDL-4 were found to be independent predictors of AIS development.

Conclusion

Our study showed that examination of LDL subclasses may be important in management of AIS patients. LDL-2, LDL-3, and LDL-4 are independent predictors of AIS development. These findings should be supported by further large studies.

Eicosapentaenoic acid improves endothelial function and nitric oxide bioavailability in a manner that is enhanced in combination with a statin

The endothelium exerts many vasoprotective effects that are largely mediated by release of nitric oxide (NO). Endothelial dysfunction represents an early but reversible step in atherosclerosis and is characterized by a reduction in the bioavailability of NO. Previous studies have shown that eicosapentaenoic acid (EPA), an omega-3 fatty acid (O3FA), and statins individually improve endothelial cell function, but their effects in combination have not been tested. Through a series of in vitro experiments, this study evaluated the effects of a combined treatment of EPA and the active metabolite of atorvastatin (ATM) on endothelial cell function under conditions of oxidative stress. Specifically, the comparative and time-dependent effects of these agents on endothelial dysfunction were examined by measuring the levels of NO and peroxynitrite (ONOO^-) released from human umbilical vein endothelial cells (HUVECs). The data suggest that combined treatment with EPA and ATM is beneficial to endothelial function and was unique to EPA and ATM since similar improvements could not be recapitulated by substituting another O3FA docosahexaenoic acid (DHA) or other TG-lowering agents such as fenofibrate, niacin, or gemfibrozil. Comparable beneficial effects were observed when HUVECs were pretreated with EPA and ATM before exposure to oxidative stress. Interestingly, the kinetics of EPA-based protection of endothelial function in response to oxidation were found to be significantly different than those of DHA. Lastly, the beneficial effects on endothelial function generated by combined treatment of EPA and ATM were reproduced when this study was expanded to an ex vivo model utilizing rat glomerular endothelial cells. Taken together, these findings suggest that a combined treatment of EPA and ATM can inhibit endothelial dysfunction that occurs in response to conditions such as hyperglycemia, oxidative stress, and dyslipidemia.

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.

Correlation between Cholesterol, Triglycerides, Calculated, and Measured Lipoproteins: Whether Calculated Small Density Lipoprotein Fraction Predicts Cardiovascular Risks

Background

Recent literature in lipidology has identified LDL-fractions to be more atherogenic. In this regard, small density LDL-cholesterol (sdLDLc) has been considered to possess more atherogenicity than other LDL-fractions like large buoyant LDL-cholesterol (lbLDLc). Recently, Srisawasdi et al. have developed a method for calculating sdLDLc and lbLDLc based upon a regression equation. Using that in developing world may provide us with a valuable tool for ASCVD risk prediction.

Objective

(1) To correlate directly measured and calculated lipid indices with insulin resistance, UACR, glycated hemoglobin, anthropometric indices, and blood pressure. (2) To evaluate these lipid parameters in subjects with or without metabolic syndrome, nephropathy, and hypertension and among various groups based upon glycated hemoglobin results.

Design

Cross-sectional study. Place and Duration of Study. From Jan 2016 to 15 April 2017.

Subjects and Methods

Finally enrolled subjects (male: 110, female: 122) were evaluated for differences in various lipid parameters, including measured LDL-cholesterol (mLDLc), HDLc and calculated LDL-cholesterol (cLDLc), non-HDLc, sdLDLC, lbLDLC, and their ratio among subjects with or without metabolic syndrome, nephropathy, glycation index, anthropometric indices, and hypertension.

Results

Significant but weak correlation was mainly observed between anthropometric indices, insulin resistance, blood pressure, and nephropathy for non-HDLc, sdLDLc, and sdLDLc/lbLDLc. Generally lipid indices were higher among subjects with metabolic syndrome [{sdLDLc: 0.92 + 0.33 versus 0.70 + 0.29 (p < 0.001)}, {sdLDLc/lbLDLc: 0.55 + 0.51 versus 0.40 + 0.38 (p = 0.010)}, {non-HDLc: 3,63 + 0.60 versus 3.36 + 0.65 (p = 0.002)}]. The fact that the sdLDLc levels provided were insignificant in Kruskall Wallis Test indicated a sharp increase in subjects with HbA1c > 7.0%. Subjects having nephropathy (UACR > 2.4 mg/g) had higher concentration of non-HDLc levels in comparison to sdLDLc [{non-HDLc: 3.68 + 0.59 versus 3.36 + 0.43} (p = 0.007), {sdLDLc: 0.83 + 0.27 versus 0.75 + 0.35 (p = NS)}].

Conclusion

Lipid markers including cLDLc and mLDLc are less associated with traditional ASCVD markers than non-HDLc, sdLDLc, and sdLDLc/lbLDLc in predicting metabolic syndrome, nephropathy, glycation status, and hypertension.

Eicosapentaenoic Acid Inhibits Oxidation of ApoB-containing Lipoprotein Particles of Different Size In Vitro When Administered Alone or in Combination With Atorvastatin Active Metabolite Compared With Other Triglyceride-lowering Agents

Eicosapentaenoic acid (EPA) is a triglyceride-lowering agent that reduces circulating levels of the apolipoprotein B (apoB)-containing lipoprotein particles small dense low-density lipoprotein (sdLDL), very–low-density lipoprotein (VLDL), and oxidized low-density lipoprotein (LDL). These benefits may result from the direct antioxidant effects of EPA. To investigate this potential mechanism, these particles were isolated from human plasma, preincubated with EPA in the absence or presence of atorvastatin (active) metabolite, and subjected to copper-initiated oxidation. Lipid oxidation was measured as a function of thiobarbituric acid reactive substances formation. EPA inhibited sdLDL (IC₅₀ ∼2.0 μM) and LDL oxidation (IC₅₀ ∼2.5 μM) in a dose-dependent manner. Greater antioxidant potency was observed for EPA in VLDL. EPA inhibition was enhanced when combined with atorvastatin metabolite at low equimolar concentrations. Other triglyceride-lowering agents (fenofibrate, niacin, and gemfibrozil) and vitamin E did not significantly affect sdLDL, LDL, or VLDL oxidation compared with vehicle-treated controls. Docosahexaenoic acid was also found to inhibit oxidation in these particles but over a shorter time period than EPA. These data support recent clinical findings and suggest that EPA has direct antioxidant benefits in various apoB-containing subfractions that are more pronounced than those of other triglyceride-lowering agents and docosahexaenoic acid.

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.

Anti-arthritogenic and cardioprotective action of hesperidin and daidzein in collagen-induced rheumatoid arthritis

Atherosclerosis has been linked to chronic inflammatory processes. Changes in the levels of lipoproteins, especially low-density lipoprotein or its variants, as well as inflammatory markers are risk factors for the atherosclerosis. In the present study, an experimental model of rheumatoid arthritis was developed by administrating collagen suspension intradermally in the tail region of Wistar albino rats. At the same time, a suspension of hesperidin (50 mg/kg body weight) and daidzein (20 mg/kg body weight) was orally administrated. The compounds were given in the morning and evening for 21 days. Levels of inflammatory markers in the homogenate of knee joints of experimental rats as well as plasma lipoproteins were investigated. The administration of hesperidin and daidzein caused significant (p < 0.001) decrease in articular elastase activity, TNF-α, and malondialdehyde levels. Further, arthritis scoring and histological findings supported the anti-inflammatory actions of the test compounds. Interestingly, the test compounds also lowered the plasma low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, and triglyceride but increased the level of high-density lipoprotein cholesterol. The test compounds thus ameliorated the risk factors of atherosclerosis. Furthermore, antioxidant roles of hesperidin as well as daidzein were evident from decrease in free radical load demonstrated as increase in total antioxidant level in plasma of arthritic animals treated with hesperidin and daidzein. In a separate in vitro experiment, enhanced free radical scavenging activity of hesperidin was demonstrated against 2,2-diphenyl-1-picrylhydrazyl and 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid. The anti-inflammatory, hypolipidemic, and antioxidant actions of the naturally occurring test compounds, particularly hesperidin, seem to be quite effective against rheumatoid arthritis and atherosclerosis. Thus, their consumption may be helpful in prevention or at least delaying the onset of these diseases in susceptible individuals.

Advanced Atherogenic Index for the Assessment of Consolidated Lipid Risk in Premature Coronary Artery Disease Patients in India

Introduction:

The high prevalence, severity, and prematurity of coronary artery disease (CAD) in the Indian population cannot be completely explained by the conventional lipid parameters and the existing lipid indices.

Aims and Objectives:

To calculate newly defined advanced atherogenic index (AAI) in premature CAD patients and compare it between cases and controls and Correlate its values with the existing indices.

Material and Methods:

One hundred and twenty premature CAD patients and an equal number of age and sex matched healthy individuals were included in this study. Lipid profile and nonconventional lipid parameters like oxidized Low density lipoprotein (OX LDL), small dense LDL (SD LDL), lipoprotein (a) apolipoprotein B (Apo B), and apolipoprotein A1 (Apo A1) were estimated and their values were used to define AAI and existing lipid indices like AI, lipid tetrad index (LTI) and lipid pentad index (LPI).

Results:

The mean age of cases and controls was 37.29 + 4.50 and 36.13 + 3.53 years, respectively. The value of AAI was highly significant in cases (3461.22 ± 45.20) as compared to controls (305.84 ± 21.80). AAI has shown better statistical significance and correlation (P < 0.0001, r = 0.737) as compared to the earlier indices such as AI (P < 0.01, r = 0.52), LTI (P < 0.001, r = 0.677) and LPI (P < 0.001, r = 0.622) in premature CAD. Kolmogorov D statistic and cumulative distribution function plot has shown that AAI can discriminate cases and controls more accurately as compared to the earlier indices.

Conclusion:

Statistically AAI appears to be a better marker of consolidated lipid risk in premature CAD patients as compared to the earlier indices.

Mimosa pudica L., a High-Value Medicinal Plant as a Source of Bioactives for Pharmaceuticals

Mimosa pudica Linn. (Family: Mimosaceae) is used as an ornamental plant due to its thigmonastic and nyctinastic movements. M. pudica is also used to avoid or cure several disorders like cancer, diabetes, hepatitis, obesity, and urinary infections. M. pudica is famous for its anticancer alkaloid, mimosine, along with several valuable secondary metabolites like tannins, steroids, flavonoids, triterpenes, and glycosylflavones. A wide array of pharmacological properties like antioxidant, antibacterial, antifungal, anti-inflammatory, hepatoprotective, antinociceptive, anticonvulsant, antidepressant, antidiarrheal, hypolipidemic activities, diuretic, antiparasitic, antimalarial, and hypoglycemic have been attributed to different parts of M. pudica. Glucuronoxylan polysaccharide extruded from seeds of M. pudica is used for drug release formulations due to its high swelling index. This review covers a thorough examination of functional bioactives as well as pharmacological and phytomedicinal attributes of the plant with the purpose of exploring its pharmaceutical and nutraceutical potentials.

Dietary cholesterol and cardiovascular disease: a systematic review and meta-analysis

BACKGROUND

Dietary cholesterol has been suggested to increase the risk of cardiovascular disease (CVD), which has led to US recommendations to reduce cholesterol intake.

OBJECTIVE

The authors examine the effects of dietary cholesterol on CVD risk in healthy adults by using systematic review and meta-analysis.

DESIGN

MEDLINE, Cochrane Central, and Commonwealth Agricultural Bureau Abstracts databases were searched through December 2013 for prospective studies that quantified dietary cholesterol. Investigators independently screened citations and verified extracted data on study and participant characteristics, outcomes, and quality. Random-effect models meta-analysis was used when at least 3 studies reported the same CVD outcome.

RESULTS

Forty studies (17 cohorts in 19 publications with 361,923 subjects and 19 trials in 21 publications with 632 subjects) published between 1979 and 2013 were eligible for review. Dietary cholesterol was not statistically significantly associated with any coronary artery disease (4 cohorts; no summary RR), ischemic stroke (4 cohorts; summary RR: 1.13; 95% CI: 0.99, 1.28), or hemorrhagic stroke (3 cohorts; summary RR: 1.09; 95% CI: 0.79, 1.50). Dietary cholesterol statistically significantly increased both serum total cholesterol (17 trials; net change: 11.2 mg/dL; 95% CI: 6.4, 15.9) and low-density lipoprotein (LDL) cholesterol (14 trials; net change: 6.7 mg/dL; 95% CI: 1.7, 11.7 mg/dL). Increases in LDL cholesterol were no longer statistically significant when intervention doses exceeded 900 mg/d. Dietary cholesterol also statistically significantly increased serum high-density lipoprotein cholesterol (13 trials; net change: 3.2 mg/dL; 95% CI: 0.9, 9.7 mg/dL) and the LDL to high-density lipoprotein ratio (5 trials; net change: 0.2; 95% CI: 0.0, 0.3). Dietary cholesterol did not statistically significantly change serum triglycerides or very-low-density lipoprotein concentrations.

CONCLUSION

Reviewed studies were heterogeneous and lacked the methodologic rigor to draw any conclusions regarding the effects of dietary cholesterol on CVD risk. Carefully adjusted and well-conducted cohort studies would be useful to identify the relative effects of dietary cholesterol on CVD risk.

Small dense LDL cholesterol measured by homogeneous assay in Japanese healthy controls, metabolic syndrome and diabetes patients with or without a fatty liver

BACKGROUND

Serum small dense LDL-cholesterol (sdLDL-C) levels in healthy controls and the cases with diabetes (T2DM) and metabolic syndrome (MetS) with or without a fatty liver in a large, typical Japanese population was determined.

METHODS

The plasma lipids and lipoproteins, including sdLDL-C by homogeneous assay, were determined in controls, MetS and T2DM patients (n=5255). The cases with MetS and preliminary MetS (pre-MetS) as well as T2DM and preliminary T2DM (pre-DM) were selected based on the Japanese criteria for MetS and T2DM. Fatty liver was diagnosed using the ultrasonography.

RESULTS

The 75th percentile values for sdLDL-C were 27.5mg/dl for men and 23.3mg/dl for women and increased with age. The concentrations of sdLDL-C and sdLDL-C/LDL-C were significantly higher in pre-MetS and pre-T2DM patients than healthy controls as well as in MetS and T2DM patients. Significantly higher sdLDL-C was found in cases with a fatty liver than without a fatty liver in all five groups.

CONCLUSIONS

Significantly elevated sdLDL-C levels were found in pre-MetS, MetS and pre-T2DM, T2DM patients compared to the healthy controls. Fatty liver significantly enhanced serum sdLDL-C levels and the multiple regression analyses ascertained that fatty liver was an independent determinant for sdLDL-C.

Association of serum triglyceride-to-HDL cholesterol ratio with carotid artery intima-media thickness, insulin resistance and nonalcoholic fatty liver disease in children and adolescents

BACKGROUND AND AIMS

The triglyceride (TG)/high-density lipoprotein-cholesterol (HDL-C) ratio has been reported as a useful marker of atherogenic lipid abnormalities, insulin resistance, and cardiovascular disease. We evaluated in a large sample of children and adolescents the association of TG/HDL-C ratio with early signs of morphological vascular changes and cardiometabolic risk factors including nonalcoholic fatty liver disease (NAFLD).

METHODS AND RESULTS

The study population, including 548 children (aged 6-16 years), of whom 157 were normal-weight, 118 overweight, and 273 obese, had anthropometric, laboratory, liver and carotid ultrasonography (carotid artery intima-media thickness-cIMT) data collected. Subjects were stratified into tertiles of TG/HDL-C. There was a progressive increase in body mass index (BMI), BMI-SD score (SDS), waist circumference, blood pressure (BP), liver enzymes, glucose, insulin, homeostasis model assessment of insulin resistance, high-sensitivity C-reactive protein (hsCRP), and cIMT values across TG/HDL-C tertiles. The odds ratios for central obesity, insulin resistance, high hsCRP, NAFLD, metabolic syndrome, and elevated cIMT increased significantly with the increasing tertile of TG/HDL-C ratio, after adjustment for age, gender, pubertal status, and BMI-SDS. In a stepwise multivariate logistic regression analysis, increased cIMT was associated with high TG/HDL-C ratio [OR, 1.81 (95% CI, 1.08-3.04); P < 0.05], elevated BP [5.13 (95% CI, 1.03-15.08); P < 0.05], insulin resistance [2.16 (95% CI, 1.30-3.39); P < 0.01], and NAFLD [2.70 (95% CI, 1.62-4.56); P < 0.01].

CONCLUSION

TG/HDL-C ratio may help identify children and adolescents at high risk for structural vascular changes and metabolic derangement.

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.

Atorvastatin active metabolite inhibits oxidative modification of small dense low-density lipoprotein

We tested the hypothesis that atorvastatin active metabolite (ATM), on the basis of its distinct structural features and potent antioxidant activity, preferentially inhibits lipid oxidation in human small dense low-density lipoprotein (sdLDL) and other small lipid vesicles. LDL, sdLDL, and various subfractions were isolated from human plasma by sequential ultracentrifugation, treated with ATM, atorvastatin, pravastatin, rosuvastatin, or simvastatin and were subjected to copper-induced oxidation. Lipid oxidation was measured spectrophotometrically as a function of thiobarbituric acid reactive substances formation. Similar analyses were performed in reconstituted lipid vesicles enriched in polyunsaturated fatty acids and prepared at various sizes. ATM was found to inhibit sdLDL oxidation in a dose-dependent manner. The antioxidant effects of ATM in sdLDL were 1.5 and 4.7 times greater (P < 0.001) than those observed in large buoyant LDL and very low-density lipoprotein subfractions, respectively. ATM had similar dose- and size-dependent effects in reconstituted lipid vesicles. None of these effects were reproduced by atorvastatin (parent) or any of the other statins examined in this study. These data suggest that ATM interacts with sdLDL in a specific manner that also confers preferential resistance to oxidative stress. Such interactions may reduce sdLDL atherogenicity and improve clinical outcomes in patients with cardiovascular disease.

The potential of Cystatin C and small dense LDL as biomarkers of coronary artery disease risk in a young Indian population

Coronary artery disease (CAD) affects Indians 5-6 years earlier than in the west, is diffuse and malignant, and poses a heavy burden on India's developing economy. Traditional risk factors have failed to explain this high incidence of premature CAD and hence this study investigated the association of two novel risk biomarkers, cystatin C and small dense LDL (sdLDL) with the presence and severity of CAD. Cystatin C and sdLDL were estimated in 204 CAD patients ≤45 years of age and compared with 161 age-matched healthy controls. The traditional lipid profile parameters, i.e., cholesterol, LDL, HDL, triglycerides, apolipoproteins A1 and B, and Lp(a) were also measured in both groups. Cystatin C was significantly raised and mean LDL particle size significantly reduced in CAD patients as compared to controls. 62.7 % of CAD patients showed pattern B while 37.3 % patients showed pattern A. Of the traditional lipid tests, only HDL and apolipoprotein A1 showed a significant decrease in the CAD group. sdLDL was significantly associated with the severity of CAD, while cystatin C was not. Both cystatin C and sdLDL emerged as independent risk factors, however, of the two, sdLDL was a more sensitive predictor of CAD events. Cystatin C and mean LDL particle size are significantly and independently associated with the presence of CAD events in patients ≤45 years with normal kidney function. Hence, these novel risk biomarkers can be useful tools in reducing the morbidity and mortality associated with CAD in the productive Indian workforce.

Association between high-normal levels of alanine aminotransferase and risk factors for atherogenesis

BACKGROUND & AIMS

Liver disease has been associated with cardiovascular disorders, but little is known about the relationship between serum levels of alanine aminotransferase (ALT) and markers of atherogenesis. We investigated the relationship between low-normal and high-normal levels of ALT and an extended panel of cardiovascular risk factors among individuals with no known diseases in a primary care setting.

METHODS

We performed a retrospective analysis of data collected from 6442 asymptomatic patients at wellness visits to a primary care setting in central Virginia from 2010 through 2011. Serum levels of ALT were compared with levels of lipids and lipoproteins, as well as metabolic, inflammatory, and coagulation-related factors associated with risk for cardiovascular disease.

RESULTS

Serum levels of ALT were higher than 40 IU/L in 12% of subjects, and in the high-normal range (19-40 IU/L in women and 31-40 IU/L in men) in 25% of subjects. ALT level was associated with the apolipoprotein B level, concentration and particle size of very-low-density lipoproteins, concentration of low-density lipoprotein (LDL) particles (LDL-P), and percentages of small dense LDL (sdLDL) and sdLDL-cholesterol (sdLDL-C) (P < .0001 for all). A high-normal level of ALT was associated with higher levels of LDL-C, LDL-P, sdLDL-C, and sdLDL particles (P < .001 for all). These effects were independent of age, body mass index, and hyperinsulinemia. Increasing levels of ALT and fasting hyperinsulinemia (>12 μU/mL) synergized with increasing levels of triglycerides, very-low-density lipoprotein particles, LDL-P, sdLDL-C, and percentage of sdLDL-C. Levels of APOA1, high-density lipoprotein-cholesterol, and high-density lipoprotein-class 2 were associated inversely with serum level of ALT (P < .0001 for all).

CONCLUSIONS

In an analysis of asymptomatic individuals, increased serum levels of ALT (even high-normal levels) are associated with markers of cardiovascular disease.