Heterogeneous properties of intermediate- and low-density lipoprotein subpopulations

A combined observational and Mendelian randomization investigation reveals NMR-measured analytes to be risk factors of major cardiovascular diseases

Dyslipidaemias is the leading risk factor of several major cardiovascular diseases (CVDs), but there is still a lack of sufficient evidence supporting a causal role of lipoprotein subspecies in CVDs. In this study, we comprehensively investigated several lipoproteins and their subspecies, as well as other metabolites, in relation to coronary heart disease (CHD), heart failure (HF) and ischemic stroke (IS) longitudinally and by Mendelian randomization (MR) leveraging NMR-measured metabolomic data from 118,012 UK Biobank participants. We found that 123, 110 and 36 analytes were longitudinally associated with myocardial infarction, HF and IS (FDR < 0.05), respectively, and 25 of those were associated with all three outcomes. MR analysis suggested that genetically predicted levels of 70, 58 and 7 analytes were associated with CHD, HF and IS (FDR < 0.05), respectively. Two analytes, ApoB/ApoA1 and M-HDL-C were associated with all three CVD outcomes in the MR analyses, and the results for M-HDL-C were concordant in both observational and MR analyses. Our results implied that the apoB/apoA1 ratio and cholesterol in medium size HDL were particularly of importance to understand the shared pathophysiology of CHD, HF and IS and thus should be further investigated for the prevention of all three CVDs.

Atherogenic Index of Plasma (AIP) a Tool to Assess Changes in Cardiovascular Disease Risk Post Laparoscopic Sleeve Gastrectomy

Predictive indices like the atherogenic index of plasma (AIP) have been developed to estimate the risk of cardiovascular disease (CVD). Metabolic surgery is the most effective treatment for a rapid improvement of morbid obesity and its comorbidities such as type 2 diabetes (T2D) and CVD. A decreased reoccurrence of CVD after metabolic surgery has been reported by several studies. However, studies utilizing predictive indices for CVD risk in CVD-free morbid-obese patients who undertook laparoscopic sleeve gastrectomy (LSG) are lacking. Here, we use AIP as a tool to evaluate the improvement in CVD risk post-LSG in morbid-obese people who had no history of CVD. Method. We compared baseline, 6- and 12-month post-LSG score of AIP, vascular age, circulating biochemical markers related to CVD in two groups of BMI and age-matched morbid-obese participants with and without T2D. Results. At baseline, people with T2D had significantly higher AIP both, with morbid obesity (0.23 ± 0.06, p < 0.001) and normal weight (0.022 ± 0.05, p < 0.001) compared to their BMI-matched without T2D group. People with morbid obesity had low AIP (-0.083 ± 0.06). Vascular age was significantly higher in people with morbid obesity and T2D (65.8 ± 3.7year, p < 0.0001) compared to morbid obesity (37.9 ± 2.6 year). After one year, AIP was significantly reduced compared to baseline score in people with morbid obesity with/without T2D, respectively (-0.135 ± 0.07, p = 0.003; and -0.36 ± 0.04, p = 0.0002). Conclusion. Our data illuminates AIP as a reliable predictive index for CVD risk in morbid-obese people who had no history of CVD. Moreover, AIP accurately distinguishes between morbid obesity with T2D and morbid obesity and showed a rapid and significant reduction in CVD risk after LSG in people who had no history of CVD. This is a ClinicalTrials.gov registered trial (Reference NCT03038373).

A Low-Molecular-Weight Phenotype of Apolipoprotein(a) as a Factor Provoking Accumulation of Cholesterol by THP-1 Monocyte-Like Cells

Increased concentration of lipoprotein(a) is a risk factor of coronary heart disease. lipoprotein(a) consists of LDL-like and highly polymorphic apolipoprotein(a). Here we studied the effect of lipoprotein(a)-containing sera with different apolipoprotein(a) phenotypes on lipid accumulation by THP-1 monocyte-like cells. Cholesterol concentration in lysates of THP-1 cells was significantly higher after their incubation with lipoprotein(a)-containing serum samples with low-molecular-weight phenotype of apolipoprotein(a) in comparison with samples with a high-molecular-weight apolipoprotein(a) phenotype irrespective of initial cholesterol level as well as serum concentrations of apoB-100, oxidized LDL, and circulating immune complexes. The presence of the most atherogenic small dense LDL subfractions in examined sera in addition to a low-molecular-weight apolipoprotein(a) phenotype resulted in significant elevation of cholesterol accumulation by THP-1 cells. The data obtained explain greater atherogenicity of lipoprotein(a) with low-molecular-weight apolipoprotein(a) phenotype.

Bergamot Reduces Plasma Lipids, Atherogenic Small Dense LDL, and Subclinical Atherosclerosis in Subjects with Moderate Hypercholesterolemia: A 6 Months Prospective Study

Background: Some patients experience statin-induced side effects or prefer nutraceutical approaches for the treatment of dyslipidemia. This has led to a search for alternative therapeutic approaches for dyslipidemia management. In recent studies Citrus bergamia (known as Bergamot) juice was able to reduce serum levels of lipids. Such benefit may be attributed to high amounts of flavonoids contained in Bergamot fruit juice (neoeriocitrin, neohesperidin, naringin). The aim of the present study was to fully investigate the effects of a Bergamot extract on cardio-metabolic parameters, including plasma lipids, atherogenic lipoproteins and subclinical atherosclerosis.

Methods: Eighty subjects (42 men and 38 women, mean age: 55 ± 13 years) with moderate hypercholesterolemia [e.g., with plasma LDL-cholesterol concentrations between 160 and 190 mg/dl (between 4.1 and 4.9 mmol/l)] were included. A Bergamot-derived extract (Bergavit R^®) was given at a fixed dose daily (150 mg of flavonoids, with 16% of neoeriocitrin, 47% of neohesperidin and 37% of naringin) for 6 months. Lipoprotein subfractions were assessed by gel electrophoresis. With this methodology low density lipoprotein (LDL) subclasses are distributed as seven bands (LDL-1 and -2 as large LDL, and LDL-3 to -7 as atherogenic small, dense LDL). Subclinical atherosclerosis was assessed by carotid intima-media thickness (cIMT) using B-mode ultrasound.

Results: After 6 months, Bergavit R^® reduced total cholesterol (from 6.6 ± 0.4 to 5.8 ± 1.1 mmol/l, p < 0.0001), triglycerides (from 1.8 ± 0.6 to 1.5 ± 0.9 mmol/l, p = 0.0020), and LDL-cholesterol (from 4.6 ± 0.2 to 3.7 ± 1.0 mmol/l, p < 0.0001), while HDL- cholesterol increased (from 1.3 ± 0.2 to 1.4 ± 0.4 mmol/l, p < 0.0007). In addition, a significant increase in LDL-1 (from 41.2 ± 0.2 to 49.6 ± 0.2%, p < 0.0001) was accompanied by decreased small, dense LDL-3, -4, and 5 particles (from 14.5 ± 0.1 to 9.0 ± 0.1% p < 0.0001; 3.2 ± 0.1 to 1.5 ± 0.1% p = 0.0053; 0.3 ± 0.0% to 0.1 ± 0.0% p = 0.0133, respectively). cIMT also decreased from 1.2 ± 0.4 to 0.9 ± 0.1 mm (p < 0.0001).

Conclusion: This is the first study investigating the effects of Bergamot flavonoids supplementation on cardio-metabolic risk in dyslipidemic subjects. Bergavit R^® (Bergamot juice extract) supplementation significantly reduced plasma lipids and improved the lipoprotein profile. cIMT was also reduced significantly over a relatively short time frame of 6 months.

Small-dense LDL/large-buoyant LDL ratio associates with the metabolic syndrome

OBJECTIVE

Heterogeneous particles of intermediate-density lipoprotein (IDL) and low-density lipoprotein (LDL) vary in atherogenesis. We investigated the association between the metabolic syndrome (MetS) score and lipoprotein subclasses.

DESIGN AND METHODS

A total of 260 outpatients were scored into six groups, based on their number of MetS components. Lipoprotein subclass determined by polyacrylamide tube gel electrophoresis separates IDL particles into three midbands (MID-A to C) and LDL into larger-buoyant (LDL1 and LDL2) and small-dense LDL (LDL3 to LDL6).

RESULTS

Mean concentrations of VLDL, MIDC, LDL2, and LDL3 to LDL6 positively correlated with increasing MetS score, but those of MIDA, LDL1 and HDL-C inversely correlated. LDL2 and LDL3 to LDL6 increased while MIDA and LDL1 decreased with increasing visceral fat, HOMA-IR, and triglycerides, with a reverse pattern for HDL-C. MIDB and MIDC were unchanged. By logistic regression, LDL1 and LDL3 to LDL6 significantly associates with the MetS score (odds ratio=0.957 and 1.077, respectively). The ratio of (LDL3 to LDL6)/LDL1 in the presence of HDL-C, showed the strongest association with MetS.

CONCLUSIONS

Respective subpopulations of IDL and LDL particles can vary in their ability to identify MetS. Because of the most strongly associated with MetS, (LDL3 to LDL6)/LDL1 ratio is proposed as an excellent marker for evaluating lipid metabolic status in patient with MetS.

Relation of plasma PCSK9 levels to lipoprotein subfractions in patients with stable coronary artery disease

Background

Plasma PCSK9 levels was positively associated with low-density lipoprotein (LDL) cholesterol (LDL-C) and atherosclerosis, while PCSK9 may also be implicated in the metabolism of lipoprotein subfractions. The study was to examine the association of plasma PCSK9 with lipoprotein subfractions in patients with stable coronary artery disease (CAD).

Methods

A total of 281 consecutive, stable CAD patients who were not treated with lipid-lowering drugs were enrolled. The baseline clinical characteristics were collected, the plasma PCSK9 levels were determined using ELISA, and the LDL and high-density lipoprotein (HDL) subfractions were analyzed by Lipoprint System. The association of plasma PCSK9 levels with the lipoprotein subfractions was investigated.

Results

In the overall population, plasma PCSK9 levels were positively associated with the concentration of LDL-C, intermediate LDL-C, small LDL-C, and LDL score, while negatively correlated with mean LDL particle size. PCSK9 levels were positively associated with the concentration of HDL-C, intermediate HDL-C and small HDL-C. Multivariable regression analysis revealed that the plasma PCSK9 levels were significantly and independently associated with the concentration of intermediate LDL-C (β = 0.152, p = 0.013), small LDL-C (β = 0.179, p = 0.004), LDL score (β = 0.121, p = 0.043), and mean LDL particle size (β = -0.130, p = 0.035), while not HDL subfractions. Interestingly, when investigated in male and female patients separately, these relationships were only found in male but not in female, and the small HDL-C exhibited an association with PCSK9 levels in male patients (β = 0.149, p = 0.045).

Conclusions

PCSK9 levels were independently associated with the changes of lipoprotein subfractions, suggesting a potential interaction between PCSK9 and lipoprotein subfractions in CAD.