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

Relative increase in production ratio of small dense low-density lipoprotein in acute coronary syndrome with high coronary plaque burden: an ex-vivo analysis

The absolute value of small dense low-density lipoprotein (sd-LDL) including small LDL (s-LDL) and very small LDL (vs-LDL) has been shown to be associated with increased incidence of atherosclerosis. However, the impact of short-timeframe increases in sd-LDL on arteriosclerosis has not yet been elucidated. Therefore, we investigated the clinical roles of ex-vivo induced sd-LDL in acute coronary syndrome (ACS) using a novel method. This is a prospective, single-blind, and observational study that screened patients who underwent coronary angiography (CAG) for the treatment of ACS or investigation of heart-failure etiology between June 2020 and April 2022 (n = 247). After excluding patients with known diabetes mellitus and advanced renal disease, the patients were further divided into the ACS (n = 34) and control (non-obstructive coronary artery, n = 34) groups. The proportion of sd-LDL (s-LDL + vs-LDL) in total lipoproteins was observed before and after 2-h incubation at 37 ℃ (to approximate physiologic conditions) using 3% polyacrylamide gel electrophoresis. The coronary plaque burden was quantified upon CAG in the ACS group. There were no significant differences between the ACS and control groups in terms of clinical coronary risk factors. The baseline of large, medium, small, and very small LDL were comparable between the two groups. Following a 2-h incubation period, significant increases were observed in the ratios of s-LDL and vs-LDL in both the ACS and control groups (ACS, p = 0.01*; control, p = 0.01*). Notably, the magnitude of increase in sd-LDL was more pronounced in the ACS group compared to the control group, with s-LDL showing a significant difference (p = 0.03*) and vs-LDL showing a tread toward significance (p = 0.08). In addition, in both groups, there was a decrease in IDL and L-LDL, while M-LDL remained unchanged. The plaque burden index and rate of short-timeframe changes in both s-LDL (p = 0.01*) and vs-LDL (p = 0.04*) before and after incubation were significantly correlated in the ACS group. The enhanced production rate of sd-LDL induced under short-term physiologic culture in an ex-vivo model was greater in patients with ACS than in the control group. The increase in sd-LDL is positively correlated with coronary plaque burden. Short-timeframe changes in sd-LDL may serve as markers for the severity of coronary artery disease.

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.

Role of Small Dense Low-density Lipoprotein Cholesterol in Cardiovascular Events in Patients with Coronary Artery Disease and Type 2 Diabetes Mellitus Receiving Statin Treatment

AIM

There is little information on the relationships of serum small dense low-density lipoprotein cholesterol (sdLDL-C) levels and serum triglyceride (TG) levels with cardiovascular events in patients with coronary artery disease (CAD) and type 2 diabetes mellitus (DM) who are receiving statins. The aim of this study was to evaluate the relationships of serum TG levels and sdLDL-C levels as residual risks for cardiovascular events in patients with CAD and type 2 DM who were being treated with statins.

METHODS

The subjects were divided into four groups based on TG levels and sdLDL-C levels: sdLDL-C of ＜40.0 mg/dL and TG of ＜150 mg/dL, sdLDL-C of ≥ 40.0 mg/dL and TG of ＜150 mg/dL, sdLDL-C of ＜40.0 mg/dL and TG of ≥ 150 mg/dL, and sdLDL-C of ≥ 40.0 mg/dL and TG of ≥ 150 mg/dL. During a median follow-up period of 1419 days, cardiovascular events occurred in 34 patients.

RESULTS

The incidences of cardiovascular events were significantly higher in patients with sdLDL-C of ≥ 40.0 mg/dL and TG of ＜150 mg/dL and in patients with sdLDL-C of ≥ 40.0 mg/dL and TG of ≥ 150 mg/dL, but not in patients with sdLDL-C of ＜40.0 mg/dL and TG of ≥ 150 mg/dL, than in patients with sdLDL-C of ＜40.0 mg/dL and TG of ＜150 mg/dL.

CONCLUSIONS

Under the condition of treatment with statins, patients with CAD and type 2 DM who had sdLDL-C levels of ≥ 40.0 mg/dL had a high risk for cardiovascular events even though serum TG levels were controlled at ＜150 mg/dL.

Serum and genetic markers related to rapid clinical progression of coronary artery disease

INTRODUCTION AND OBJECTIVES

Patients with clinically evident coronary artery disease differ in their rate of progression, which impacts prognosis. We aimed to characterize serum and genetic markers in patients with rapid clinical progression (RCP) of coronary artery disease vs those with long standing stable (LSS) disease.

METHODS

Retrospective study of cases (RCP) and controls (LSS) (1:2). Patients requiring ≥ 2 revascularizations due to atherosclerotic progression in the 10 years after a first angioplasty were considered to be RCP and those without events during the same period after the first angioplasty were considered to have LSS disease. After patient selection, we analyzed serum values, mRNA expression and genetic polymorphisms of inflammatory markers, including interleukin-6, C-reactive protein, and tumor necrosis factor (TNF)-a, and atherogenic markers consisted of proprotein convertase subtilisin/kexin type 9 (PCSK9), low-density lipoprotein receptor, sterol regulatory element binding transcription factor 2, and apolipoprotein-B.

RESULTS

The study included 180 patients (58 RCP and 122 LSS). Demographic characteristics, classic risk factors and the extent of coronary disease were similar in the 2 groups. Patients with RCP showed higher serum levels of interleukin-6 and PCSK9 and higher TNF mRNA expression. Interleukin-6 rs180075C, TNF rs3093664 non-G and PCSK9 rs2483205 T alleles conferred a risk of RCP (P<.05 in all cases). Among patients with RCP, 51.7% had all 3 risk alleles vs 18% of those with LSS (P<.001).

CONCLUSIONS

We suggest the existence of specific phenotypic and genotypic markers associated with RCP of coronary artery disease that could help to individualize the type and intensity of treatment.

Impact of Pemafibrate Therapy on Reducing Small Dense Low-Density-Lipoprotein-Cholesterol Levels in Patients with Hypertriglyceridemia

BACKGROUND

Small dense LDL-cholesterol is a recently discovered cardiovascular risk factor beyond LDL-cholesterol. Pemafibrate is a novel selective peroxisome proliferator-activated receptor-α modulator that reduces triglyceride levels. Given the significant association between triglycerides and small dense LDL-cholesterol levels, pemafibrate may reduce the levels of small dense LDL-cholesterol.

METHODS

Patients with hypertriglyceridemia who started pemafibrate therapy and continued it for >3 months between 2018 and 2022 were included in this retrospective study. The levels of small dense LDL-cholesterol, which was estimated using Sampson's equation, consisting of the LDL-cholesterol and triglyceride levels, were compared between baseline and 3-month follow-up.

RESULTS

A total of 98 patients receiving pemafibrate therapy (median age: 63 years, 69 male) were eligible, including 33 patients (34%) who received concomitant statins. Small dense LDL-cholesterol levels decreased significantly during the course of 3-month pemafibrate therapy from 48.9 (IQR: 35.7, 57.9) mg/dL to 38.8 (IQR: 30.0, 45.1) mg/dL, regardless of the concomitant administration of statins (p < 0.001). The rate of cardiovascular events decreased significantly from the pre-treatment 1-year period to the treatment 1-year period (from 13 to 2 events, from 0.133 to 0.021 events per year, incidence rate ratio: 0.16, 95% confidence interval: 0.14-0.17, p < 0.001).

CONCLUSIONS

Pemafibrate therapy may mitigate the concentrations of small dense LDL-cholesterol autonomously in patients manifesting hypertriglyceridemia within the authentic clinical milieu. The clinical importance of the diminishment in small dense LDL-cholesterol instigated via pemafibrate merits further scrutiny.

Association between Intermediate-Density Lipoprotein Particles and the Progression of Carotid Atherosclerosis: A Community-Based Cohort Study

AIM

Experimental studies report that intermediate-density lipoprotein (IDL), the precursor of low-density lipoprotein, promotes atherosclerotic plaque formation. However, whether IDL is involved in the development of atherosclerosis in humans is still unclear. The aim of this community-based study is to examine the association between IDL particle (IDL-P) concentrations and the 5-year progression of carotid atherosclerosis.

METHODS

Baseline IDL-P concentrations were measured using nuclear magnetic resonance spectroscopy in 927 participants aged 45-74 years with no history of cardiovascular disease (CVD) at baseline. To estimate the association between baseline IDL-P concentrations and 5-year progression of carotid atherosclerosis, indicated by atherosclerotic plaque progression and changes in total plaque area (TPA), multivariable-adjusted regression was employed.

RESULTS

During the 5-year follow-up period, 45.8% of participants developed new plaques. Baseline IDL-P concentrations were significantly associated with the progression of carotid atherosclerosis. Participants in the highest quartile of IDL-P concentrations exhibited 1.36-fold (95% confidence interval [CI]: 1.09-1.68) increased progression of carotid plaque and 1.67-fold (95% CI: 1.04-2.69) higher TPA than those in the lowest quartile. These relationships were independent of baseline concentrations of low-density lipoprotein particles and very-low-density lipoprotein particles and their subclasses.

CONCLUSIONS

Elevated IDL-P concentrations were independently associated with the progression of carotid atherosclerosis, suggesting that IDL-P is a novel risk factor for the development of atherosclerosis.

Effect of Body Mass Index on the Prognostic Value of Atherogenic Index of Plasma in Patients with Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention

(1) Background: The aim of this study was to investigate whether the prognostic value of the atherogenic index of plasma (AIP) for adverse cardiovascular events in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI) varied across different BMI groups. (2) Methods: This study was a retrospective analysis of a prospective registry involving 1725 ACS patients undergoing PCI. The primary endpoint was a composite of all-cause death, non-fatal ischemic stroke, non-fatal spontaneous myocardial infarction (MI), and unplanned repeat revascularization. (3) Results: The study population finally consisted of 526 patients with BMI < 24 kg/m2 (age 62 ± 10 years; male 64.3%), 827 patients with 24 kg/m2 ≤ BMI < 28 kg/m2 (age 60 ± 10 years; male 81.8%), and 372 patients with BMI ≥ 28 kg/m2 (age 57 ± 11 years; male 81.2%). The AIP as a continuous variable increased the risk for the primary endpoint in ACS patients undergoing PCI with BMI < 24 kg/m2 (HR 2.506; 95% CI 1.285-4.885; p = 0.007), while it did not increase the risk in patients with BMI ≥ 24 kg/m2 (hazard ratio [HR]: 1.747; 95% CI 0.921-3.316; p = 0.088 for patients with 24 kg/m2 ≤ BMI < 28 kg/m2; and HR: 2.096; 95% CI 0.835-5.261; p = 0.115 for patients with BMI ≥ 28 kg/m2, respectively). Compared with the lowest AIP tertile, the top AIP tertile was associated with a significantly increased risk of the primary endpoint in BMI < 24 kg/m2 group (HR: 1.772, 95% CI: 1.110 to 2.828, p = 0.016). (4) Conclusions: The AIP was significantly associated with an increased risk of adverse cardiovascular events in ACS patients undergoing PCI with BMI < 24 kg/m2, but not in the patients with BMI ≥ 24 kg/m2.

Low-density lipoprotein cholesterol and risk of hepatocellular carcinoma: a Mendelian randomization and mediation analysis

BACKGROUND

A previous study demonstrated that low-density lipoprotein cholesterol (LDL-C) is associated with hepatocellular carcinoma (HCC); however, the causality between them has not been proven due to conflicting research results and the interference of confounders. This study utilized Mendelian randomization (MR) to investigate the causal relationship between LDL-C and HCC and identify the mediating factors.

METHODS

LDL-C, HCC, and coronary artery disease (CAD) genome-wide association study (GWAS) data were obtained from a public database. To investigate causality, inverse variance weighting (IVW) was the main analysis approach. MR‒Egger, simple mode, weighted median (WM), and weighted mode were employed as supplementary analytic methods. In addition, horizontal pleiotropy and heterogeneity were tested. To evaluate the stability of the MR results, a "leave-one-out" approach was used. Multivariate MR (MVMR) was utilized to correct the confounders that might affect causality, and mediation analysis was used to investigate the potential mediating effects. Finally, we used HCC risk to infer the reverse causality with LDL-C level.

RESULTS

Random effects IVW results were (LDL-C-HCC: odds ratio (OR) = 0.703, 95% confidence interval (CI) = [0.508, 0.973], P = 0.034; CAD-HCC: OR = 0.722, 95% CI = [0.645, 0.808], P = 1.50 × 10^-8; LDL-C-CAD: OR = 2.103, 95% CI = [1.862, 2.376], P = 5.65 × 10^-33), demonstrating a causal link between LDL-C levels and a lower risk of HCC. Through MVMR, after mutual correction, the causal effect of LDL-C and CAD on HCC remained significant (P < 0.05). Through mediation analysis, it was proven that CAD mediated the causative connection between LDL-C and HCC, and the proportion of mediating effect on HCC was 58.52%. Reverse MR showed that HCC could affect LDL-C levels with a negative correlation (OR_IVW = 0.979, 95% CI = [0.961, 0.997], P = 0.025).

CONCLUSION

This MR study confirmed the causal effect between LDL-C levels and HCC risk, with CAD playing a mediating role. It may provide a new view on HCC occurrence and development mechanisms, as well as new metabolic intervention targets for treatment.

The Value of the Apolipoprotein B/Apolipoprotein A1 Ratio in Predicting the Rapid Progression of Non-Culprit Coronary Lesions in Acute Coronary Syndrome in Patients with Diabetes Mellitus after Percutaneous Coronary Intervention

This study aims to assess the predictive value of the apolipoprotein B (ApoB) /apolipoprotein A1 (ApoA1) ratio in acute coronary syndrome (ACS) in patients with diabetes mellitus (DM) for the rapid progression (RP) of non-culprit coronary lesions (NCCLs) after percutaneous coronary intervention (PCI) and observe the effect of the ApoB/ApoA1 ratio on major adverse cardiac events (MACE).A total of 175 patients with DM presenting with ACS who received a PCI and an average 13-month follow-up coronary angiography (CAG) were enrolled from January 2015 to December 2020. According to the CAG, the patients were divided into the RP group and the non-RP group. MACE was defined as a composite of death from cardiac causes, cardiac arrest, myocardial infarction, or rehospitalization from unstable or progressive angina at the end of a 24-month follow-up.The low-density lipoprotein cholesterol (LDL-C), ApoB, ApoB/ApoA1 ratio, and LDL-C/high-density lipoprotein cholesterol (HDL-C) ratio levels at baseline were significantly higher in the RP group than in the non-RP group. The ApoA1 level at baseline in the non-RP group was significantly higher than in the RP group. The predictive significance of the ApoB/ApoA1 ratio (area under the curve (AUC) = 0.712) for the RP of NCCLs was significantly higher than those of ApoA1, ApoB, LDL-C/HDL-C ratio (AUC = 0.628, AUC = 0.640, and AUC = 0.620, respectively). A higher ApoB/ApoA1 ratio and the RP of NCCLs were significantly associated with the occurrence of MACE.The ApoB/ApoA1 ratio was an effective clinical indicator for the RP of NCCLs after PCI in patients with DM presenting with ACS. The high ApoB/ApoA1 ratio and the RP of NCCLs were two risks for MACE.

Novel Biomarkers for Atherosclerotic Disease: Advances in Cardiovascular Risk Assessment

Atherosclerosis is a significant health concern with a growing incidence worldwide. It is directly linked to an increased cardiovascular risk and to major adverse cardiovascular events, such as acute coronary syndromes. In this review, we try to assess the potential diagnostic role of biomarkers in the early identification of patients susceptible to the development of atherosclerosis and other adverse cardiovascular events. We have collected publications concerning already established parameters, such as low-density lipoprotein cholesterol (LDL-C), as well as newer markers, e.g., apolipoprotein B (apoB) and the ratio between apoB and apoA. Additionally, given the inflammatory nature of the development of atherosclerosis, high-sensitivity c-reactive protein (hs-CRP) or interleukin-6 (IL-6) are also discussed. Additionally, newer publications on other emerging components linked to atherosclerosis were considered in the context of patient evaluation. Apart from the already in-use markers (e.g., LDL-C), emerging research highlights the potential of newer molecules in optimizing the diagnosis of atherosclerotic disease in earlier stages. After further studies, they might be fully implemented in the screening protocols.

Association with carotid plaque parameters detected on contrast-enhanced ultrasound and coronary artery plaque progression in non-culprit lesions: A retrospective study

AIM

To investigate the correlation between carotid plaque parameters detected on contrast-enhanced ultrasound(CEUS) and the plaque progression in non-culprit coronary lesions (NCCLs) after percutaneous coronary intervention (PCI).

METHODS

In this retrospective cross-sectional study, we analyzed 173 patients who underwent PCI. Patients were stratified into two groups (progression and non-progression groups) by comparing the coronary angiography (CAG) results at baseline and follow-up. The correlation between carotid plaque parameters and plaque progression in NCCLs was analyzed by multivariate logistic regression analysis. A logistic regression model was established to predict NCCLs progression.

RESULTS

Overall, 55 of 173 patients exhibited NCCLs progression (31.79%). Univariate comparisons showed that plaque thickness, plaque length, and IPN score were significantly higher in the progressive group than in the non-progressive group (P < 0.01). Multivariate logistic regression analysis revealed that carotid plaque length (OR = 3.418, 95% CI =1.101-10.610) and IPN score (OR = 7.395, 95% CI =3.154-17.342) were strongly associated with plaque progression in NCCLs. After adjusting for confounders, the history of previous PCI, plaque length, and IPN score were independent predictors of the NCCLs progression (P < 0.05). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the logistic regression model in predicting the NCCLs progression were 62.50%, 90.53%, 81.12%, 76.92%, and 82.69%, respectively, and the area under the receiver operating characteristic (ROC) curve was 0.882 (95% CI: 0.826-0.939).

CONCLUSIONS

Carotid plaque length and IPN score were strongly correlated with plaque progression in NCCLs. Combining the history of previous PCI can reasonably predict the NCCLs progression.

Impact of triglyceride-rich lipoproteins on early in-stent neoatherosclerosis formation in patients undergoing statin treatment

BACKGROUND

Neoatherosclerosis (NA), which refers to neointimal atherosclerosis within a stent, is considered one of the underlying causes of late-phase stent failure following a newer generation drug-eluting stent (DES) placement procedure. Even contemporary guideline-directed medical therapy may be insufficient to prevent NA.

OBJECTIVE

This study aimed to investigate how intricately lipid markers are associated with NA formation in the early phase of treatment with well-maintained low-density lipoprotein cholesterol (LDL-C) levels.

METHODS

We enrolled 114 consecutive patients undergoing statin treatment and percutaneous coronary intervention (PCI) with current-generation DES for coronary artery disease. At a median 12 months after PCI, optical coherence tomography (OCT) was performed. Various lipid markers, including LDL-C, triglyceride (TG), triglyceride-rich lipoprotein cholesterol (TRL-C), non-high-density lipoprotein cholesterol (non-HDL-C), malondialdehyde-modified LDL (MDA-LDL), and several apolipoproteins, were also evaluated.

RESULTS

NA was observed in 17 (14.9%) patients. The LDL-C level was equivalent in patients with or without NA (77.2 vs. 69.8 mg/dL; p=0.15). However, the levels of TG, apolipoprotein C3 (apoC3), TRL-C, non-HDL-C, and apolipoprotein B (apoB), and MDA-LDL were significantly higher in the patients with NA. Furthermore, multivariate logistic regression adjusting for HbA1c and stent duration revealed apoC3, TRL-C, non-HDL-C, apoB, and MDA-LDL levels as risk factors for NA. However, when apoB was included as a covariate, other factors became nonsignificant.

CONCLUSIONS

Abnormal triglyceride-rich lipoprotein metabolism and high atherogenic apoB-containing lipoprotein particle numbers are associated with the formation of NA in patients undergoing statin treatment at a median 12 months post-PCI.

Prognostic Implication of Small Dense LDL-Cholesterol Levels following Acute Coronary Syndrome

Background and Objectives: Small dense LDL cholesterol is a strong risk factor for atherosclerosis. However, few studies have investigated the impacts of this specific lipid profile on the incident risk of adverse cardiovascular events in patients with acute coronary syndrome. Materials and Methods: Patients with acute coronary syndrome, who underwent revascularization, were included and followed for 2 years. The levels of small dense LDL cholesterol were measured at index discharge (day 0) in the setting of newly administered therapies for secondary prevention, including aspirin and statins, during the index hospitalization. The prognostic impact of small dense LDL-cholesterol levels on the risk of a primary composite endpoint, including cardiac death, non-fatal myocardial infarction, unstable angina pectoris, stroke, and heart failure, was investigated. Results: In total, 46 patients (median 75 (59, 83) years old, 63% men) were included. Median small dense LDL cholesterol was 19.4 (13.5, 23.8) mg/dL at index discharge. All patients initiated statin treatment before the index discharge, with a median LDL-cholesterol level of 77 (64, 109) mg/dL. Small dense LDL-cholesterol level was independently associated with an incremental risk for the primary endpoint (p < 0.05 by adjusting for several potential risk factors, including LDL cholesterol) with a cutoff of 32.6 mg/dL. Conclusions: Small dense LDL-cholesterol level was a significant risk factor for cardiovascular events following presentations of acute coronary syndrome.

Estimation of Small Dense LDL-Cholesterol Levels in Patients with Acute Coronary Syndrome

Small dense LDL-cholesterol is an established risk factor for atherosclerosis, but it is not routinely measured in clinical practice, and its measurement has not yet been reimbursed. The Sampson equation that uses triglyceride and LDL-cholesterol levels has very recently been proposed to estimate small dense LDL-cholesterol levels. We validated its accuracy in patients with acute coronary syndrome.Serum samples were obtained on admission from hospitalized patients with acute coronary syndrome before heparinization. Small dense LDL-cholesterol levels were measured directly and were also estimated from triglyceride and LDL-cholesterol levels using the Sampson equation. The correlation between the Sampson's equation and direct measurement was investigated.A total of 55 patients were enrolled. The median age was 75 (65, 84) years old, and 35 (64%) were men. There was a moderate correlation between the two methods (r = 0.76, P < 0.001). A lower level of small dense LDL-cholesterol was independently associated with a greater overestimation of the Sampson equation.The Sampson equation is useful for estimating small dense LDL-cholesterol levels in patients with acute coronary syndrome. However, the estimated value may be overestimated in patients with low lipid profiles.

Low-density lipoprotein particles in atherosclerosis

Among the diseases causing human death, cardiovascular disease (CVD) remains number one according to the World Health Organization report in 2021. It is known that atherosclerosis is the pathological basis of CVD. Low-density lipoprotein (LDL) plays a pivotal role in the initiation and progression of atherosclerotic CVD (ASCVD). LDL cholesterol (LDL-C) is the traditional biological marker of LDL. However, large numbers of patients who have achieved the recommended LDL-C goals still have ASCVD risk. In multiple prospective studies, LDL particle (LDL-P) is reported to be more accurate in predicting CVD risk than LDL-C. LDL-Ps differ in size, density and chemical composition. Numerous clinical studies have proved that the atherogenic mechanisms of LDL-Ps are determined not only by LDL number and size but also by LDL modifications. Of note, small dense LDL (sdLDL) particles possess stronger atherogenic ability compared with large and intermediate LDL subfractions. Besides, oxidized LDL (ox-LDL) is another risk factor in atherosclerosis. Among the traditional lipid-lowering drugs, statins induce dramatic reductions in LDL-C and LDL-P to a lesser extend. Recently, proprotein convertase subtilsin/kexin type 9 inhibitors (PCSK9i) have been demonstrated to be effective in lowering the levels of LDL-C, LDL-P, as well as CVD events. In this article, we will make a short review of LDL metabolism, discuss the discordance between LDL-C and LDL-P, outline the atherogenic mechanisms of action of LDL by focusing on sdLDL and ox-LDL, summarize the methods used for measurement of LDL subclasses, and conclude the advances in LDL-lowering therapies using statins and PCSK9i.

Excessive Visit-to-Visit Small and Dense Low-Density Lipoproteins Elevate Cerebral Small Vessel Disease Progression Risk in the Elderly

Objective

Small and dense low-density lipoprotein (sdLDL) elevation may be among the most sensitive early biomarkers for nascent cardiovascular disease. This study, therefore, investigated the association between visit-to-visit changes in sdLDL and cerebral small vessel disease (CSVD) progression in older individuals, and the influence of Apolipoprotein E (APOE) genotype on this association.

Methods

Between April 2007 and July 2009, 1,143 participants ≥60 years old were recruited from the Shandong region of China, and sdLDL was measured at baseline and at each follow-up visit. White matter hyperintensities (WMHs), lacunes, microbleeds, and enlarged perivascular spaces (EPVSs) were assessed by magnetic resonance imaging. The APOE genotype was determined and participants were stratified as ε4-positive or ε4-negative.

Results

During an average follow-up of 86.0 months, 225 participants (19.7%) developed WMH progression, 193 (16.9%) lacune progression, 170 (14.9%) microbleed progression, and 185 (16.2%) EPVS progression. Compared with patients in the first (lowest) tertile of visit-to-visit mean sdLDL, those in the second and third tertiles demonstrated significantly greater risks of WMH progression (53.5 and 105.3% higher), lacune progression (53.3 and 60.8%), microbleed progression (47.2 and 127.6%), and EPVS progression (54.0 and 135.0%) after adjustment for confounders (all adjusted P values for trends <0.001). Compared with patients in the first tertile of visit-to-visit sdLDL SD, those in the second and third tertiles also demonstrated significantly greater risks of WMH progression (49.9% and 143.6%), lacune progression (75.3 and 178.0%), microbleed progression (12.7 and 64.7%), and EPVS progression (41.7 and 114.6%) after adjustment (all P < 0.001). There were significant and positive visit-to-visit mean sdLDL × visit-to-visit sdLDL SD, visit-to-visit mean sdLD×ε4-positive, visit-to-visit sdLDL SD×ε4-positive, and visit-to-visit mean sdLDL×visit-to-visit sdLDL SD×ε4-positive interactions influencing CSVD progression after confounder adjustment (all P < 0.05).

Conclusion

Large and variable visit-to-visit changes in sdLDL are independent predictors of aggressive CSVD progression, and this association is strongly influenced by APOE ε4 allele genotype.

Atherosclerosis Development and Progression: The Role of Atherogenic Small, Dense LDL

Atherosclerosis is responsible for large cardiovascular mortality in many countries globally. It has been shown over the last decades that the reduction of atherosclerotic progression is a critical factor for preventing future cardiovascular events. Low-density lipoproteins (LDL) have been successfully targeted, and their reduction is one of the key preventing measures in patients with atherosclerotic disease. LDL particles are pivotal for the formation and progression of atherosclerotic plaques; yet, they are quite heterogeneous, and smaller, denser LDL species are the most atherogenic. These particles have greater arterial entry and retention, higher susceptibility to oxidation, as well as reduced affinity for the LDL receptor. Increased proportion of small, dense LDL particles is an integral part of the atherogenic lipoprotein phenotype, the most common form of dyslipidemia associated with insulin resistance. Recent data suggest that both genetic and epigenetic factors might induce expression of this specific lipid pattern. In addition, a typical finding of increased small, dense LDL particles was confirmed in different categories of patients with elevated cardiovascular risk. Small, dense LDL is an independent risk factor for cardiovascular diseases, which emphasizes the clinical importance of both the quality and the quantity of LDL. An effective management of atherosclerotic disease should take into account the presence of small, dense LDL in order to prevent cardiovascular complications.

A New Look at Novel Cardiovascular Risk Biomarkers: The Role of Atherogenic Lipoproteins and Innovative Antidiabetic Therapies

The presence of residual cardiovascular disease (CVD) risk is a current dilemma in clinical practice; indeed, despite optimal management and treatment, a considerable proportion of patients still undergo major CV events. Novel lipoprotein biomarkers are suggested as possible targets for improving the outcomes of patients at higher risk for CVD, and their impact on major CV events and mortality have previously been investigated. Innovative antidiabetic therapies have recently shown a significant reduction in atherogenic lipoproteins, beyond their effects on glucose parameters; it has also been suggested that such anti-atherogenic effect may represent a valuable mechanistic explanation for the cardiovascular benefit of, at least, some of the novel antidiabetic agents, such as glucagon-like peptide-1 receptor agonists. This emphasizes the need for further research in the field in order to clearly assess the effects of innovative treatments on different novel biomarkers, including atherogenic lipoproteins, such as small dense low-density lipoprotein (LDL), lipoprotein(a) (Lp(a)) and dysfunctional high-density lipoprotein (HDL). The current article discusses the clinical importance of novel lipid biomarkers for better management of patients in order to overcome residual cardiovascular risk.

Atherogenic Index of Plasma and Coronary Artery Disease in the Adult Population: A Meta-Analysis

Background: The atherogenic index of plasma (AIP), which is the logarithm of the ratio between the triglyceride and high-density lipoprotein cholesterol (TG/HDL-C) concentrations in molar units, is correlated with the burden of atherosclerosis. This study aimed to evaluate the association between the AIP and coronary artery disease (CAD) in the adult population by performing a meta-analysis. Methods: Observational studies relevant for this meta-analysis were identified by searching the PubMed, Embase, and Web of Science databases. Only studies using multivariate analysis were considered. A random-effects model, which incorporates potential intra-study heterogeneity, was applied to combine the results. Results: Ten observational studies were included. In studies with the AIP analyzed as a continuous variable, a higher AIP was associated with a higher odds of CAD (adjusted risk ratio [RR] per 1-standard deviation [SD] increment of AIP: 2.10, 95% confidence interval [CI]: 1.51-2.93, P < 0.001, I² = 90%). Further analysis of studies with the AIP analyzed as a categorical variable showed a higher odds of CAD (adjusted RR: 2.35, 95% CI: 1.88-2.93, P < 0.001, I² = 37%) in the participants with the highest versus the lowest AIP value. Subgroup analyses demonstrated consistent results in asymptomatic and symptomatic populations as well as in male and female participants (all between-group P values > 0.05). Discussion: Current evidence, mostly from cross-sectional studies, suggests that a higher AIP value may be independently associated with CAD in the adult population.

Triglyceride and Small Dense LDL-Cholesterol in Patients with Acute Coronary Syndrome

BACKGROUND

Small dense LDL-cholesterol is an established risk factor for atherosclerosis but is not routinely measured in daily practice. The association between small dense LDL-cholesterol and triglyceride, which in turn is routinely measured, in patients with acute coronary syndrome remains unknown.

METHODS

Consecutive patients with acute coronary syndrome who were admitted to our institute were prospectively included, and serum samples were obtained on admission. The association between small dense LDL-cholesterol and triglyceride was investigated.

RESULTS

Among 55 patients (median 71 years old, 64% men), median (interquartile range) small dense LDL-cholesterol was 23.6 (17.0, 36.0) and triglyceride was 101 (60, 134) mg/dL. Triglyceride level correlated with small dense LDL-cholesterol (r = 0.67, p < 0.001) and was an independent determinant of small dense LDL-cholesterol together with body mass index (p = 0.010 and p = 0.008, respectively). Those with high triglyceride and high body mass index had a 3-fold level of small dense LDL-cholesterol compared with those with low triglyceride and low body mass index (45.8 [35.0, 54.0] mg/dL versus 15.0 [11.6, 23.7] mg/dL, p = 0.001).

CONCLUSIONS

Triglyceride level was a major determinant of small dense LDL-cholesterol in patients with acute coronary syndrome. Triglyceride level might be a useful and practical biomarker for risk stratification for patients with acute coronary syndrome together with body mass index.