Apolipoprotein C3 and Necrotic Core Volume Are Correlated but Also Associated With Future Cardiovascular Events

We aimed to clarify the relationship between apolipoprotein C3 (apo-C3) and vascular composition of lesion plaque in stable coronary disease (SCD) before percutaneous coronary intervention (PCI) and to investigate major adverse cardiovascular events (MACEs) within 4 years. Data of 98 consecutive patients with SCD who underwent PCI between November 1, 2012, and March 10, 2015, were analyzed. Laboratory evaluation and virtual histology-intravascular ultrasound (VH-IVUS) examination of culprit lesions were conducted before PCI. Patients were divided according to the median apo-C3 value into low apo-C3 (≤8.5 mg/dL) and high apo-C3 (>8.5 mg/dL) groups. VH-IVUS data indicated that the percentage of necrotic core volume (%NC) was significantly higher in the high apo-C3 group than in the low apo-C3 group. Moreover, the %NC significantly correlated with the apo-C3 level (R=0.2109, P=0.037). Kaplan–Meier curve analysis revealed that freedom from MACEs decreased more in the high apo-C3 group than in the low apo-C3 group and in the high %NC group than in the low %NC group. Multivariate Cox hazards analysis showed that the %NC and high apo-C3 were independent predictors of 4-year MACEs. Apo-C3 may be a useful marker for future MACEs in patients with SCD after PCI and contribute to %NC growth.

CRISPR/Cas9-mediated knockout of APOC3 stabilizes plasma lipids and inhibits atherosclerosis in rabbits

Background High levels of apolipoprotein C3 (APOC3) can lead to hypertriglyceridemia, which increases the risk of cardiovascular disease. We aim to create APOC3-knockout (KO) rabbits and explore the effects of APOC3 deletion on the occurrence and development of atherosclerosis. Methods An sgRNA anchored to exon 2 of APOC3 was designed to edit embryo genomes using the CRISPR/Cas9 system. The founder rabbits were sequenced, and their lipid profile, inflammatory cytokines, and atherosclerotic plaques were analyzed. Results When given a normal chow (NC) diet, all APOC3-KO rabbits had 50% lower triglyceride (TG) levels than those of the matched age control group. Additionally, their plasma lipoprotein lipase increased. When fed a high-fat diet, APOC3 deficiency was observed to be more conducive to the maintenance of plasma TG, total cholesterol, and low-density lipoprotein cholesterol levels, and the inhibition of the inflammatory response and the protection against atherosclerosis in rabbits. Conclusion APOC3 deficiency can delay the formation of atherosclerosis-induced HFD in rabbits, indicating this is a novel therapeutic target to treat atherosclerosis.

PCSK9 Activity Is Potentiated Through HDL Binding

Rationale: Proprotein convertase subtilisin/kexin type 9 (PCSK9) circulates in a free and lipoprotein-bound form, yet the functional consequence of the association between PCSK9 and high-density lipoprotein (HDL) remains unexplored. Objective: This study sought to interrogate the novel relationship between PCSK9 and HDL in humans. Methods and Results: Comparing lipoprotein and apolipoprotein profiles by nuclear magnetic resonance and targeted mass spectrometry measurements with PCSK9 levels in the community-based Bruneck (n=656) study revealed a positive association of plasma PCSK9 with small HDL, alongside a highly significant positive correlation between plasma levels of PCSK9 and apolipoprotein-C3, an inhibitor of lipoprotein lipase. The latter association was replicated in an independent cohort, the SAPHIR study (n=270). Thus, PCSK9-HDL association was determined during the postprandial response in two dietary studies (n=20 participants each, 8 times points). Peak triglyceride levels coincided with an attenuation of the PCSK9-HDL association, a loss of apolipoprotein-C3 from HDL and lower levels of small HDL as measured by nuclear magnetic resonance. Crosslinking mass spectrometry (XLMS) upon isolated HDL identified PCSK9 as a potential HDL-binding partner. PCSK9 association with HDL was confirmed through size-exclusion chromatography and immuno-isolation. Quantitative proteomics upon HDL isolated from patients with coronary artery disease (n=172) returned PCSK9 as a core member of the HDL proteome. Combined interrogation of the HDL proteome and lipidome revealed a distinct cluster of PCSK9, phospholipid transfer protein, clusterin and apolipoprotein-E within the HDL proteome, that was altered by sex and positively correlated with sphingomyelin content. Mechanistically, HDL facilitated PCSK9-mediated low-density lipoprotein receptor degradation and reduced low-density lipoprotein uptake through the modulation of PCSK9 internalisation and multimerisation. Conclusions: This study reports HDL as a binder of PCSK9 and regulator of its function. The combination of -omic technologies revealed postprandial lipaemia as a driver of PCSK9 and apolipoprotein-C3 release from HDL.

CRISPR/Cas9-Mediated Knockout of APOC3 Stabilizes Plasma Lipids and Inhibits Atherosclerosis in Rabbits

Background: High levels of apolipoprotein C3 (APOC3) can lead to hypertriglyceridemia, which increases the risk of cardiovascular disease. We aim to create APOC3 knockout (KO) rabbits and explore the effects of APOC3 deletion on the occurrence and development of atherosclerosis.Methods: A sgRNA anchored to exon 2 of APOC3 was designed to edit embryos using the CRISPR/Cas9 system. The founder rabbits were sequenced, and their lipid profile, inflammatory cytokines and atherosclerotic plaques were analyzed.Results: When given a normal chow (NC) diet, all APOC3 KO rabbits had low plasma TG level, which was two times lower than that of the matched age control group. Additionally, their plasma lipoprotein lipase (LPL) increased. When fed a high-fat diet (HFD), it was observed that APOC3 deficiency was more conducive to the maintenance of plasma TG, total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels in rabbits, the inhibition of inflammatory response and the protection of atherosclerosis in rabbits.Conclusion: APOC3 KO rabbit models can be obtained with the CRISPR/Cas9 system to combat the formation of HFD-induced atherosclerosis, indicating a novel therapeutic target to treat atherosclerosis.

Polymorphism in Genes Apolipoprotein C3 (APOC3) and Fatty Acid-Binding Proteins (FABP2) in Nondiabetic Dyslipidemics: A Tertiary Care Hospital-Based Pilot Study

Context Dyslipidemia is a multifactorial disease in which lipoproteins play an important role as one of the early markers for coronary heart disease (CHD). Mixed dyslipidemia is common in people with diabetes mellitus, but nondiabetic dyslipidemics (NDD) remain unidentified for the risk of developing dyslipidemia and eventually CHD. Objectives This pilot study attempts to analyze the genetic basis of lipid metabolism alterations, emphasizing the association between fatty acid-binding protein-2 (FABP2-Ala54Thr) and apolipoprotein-C3 (APOC3-rs5128) genetic polymorphism, as a risk for developing dyslipidemia and CHD in NDD. Methods and Design Total 90 subjects—30 DD, 30 NDD, and 30 apparently healthy subjects representing Central India—were included. Biochemical analysis and DNA genotyping were done by polymerase chain reaction restriction fragment length polymorphism. Statistical Analysis The biochemical parameters were reported as means ± standard deviation. One-way analysis of variance test was used to compare biochemical parameters of three groups. Chi-squared test was done to compare genotype distributions. The strength of association was assessed by odds ratios (ORs) with 95% confidence intervals (CIs). All statistical analysis was done using SPSS-PC software and Graph Pad. Results In NDD, maximum polymorphism was observed followed by DD and least polymorphism was observed in controls. There was a significant association of APOC3 G allele with occurrence of hypertriglyceridemia (p < 0.05); however, no such association was found for FABP2 A allele (p > 0.05). Logistic regression analysis revealed APOC3 polymorphism to be significantly associated with dyslipidemia (OR = 2.6667, 95% CI = 1.0510–6.7663, p = 0.0341); no such association was found for FABP2 polymorphism (OR = 0.4643, 95% CI = 0.1641–1.3136, p = 0.1347). The triglyceride and cholesterol values in individuals with homozygous genotype indicate that genetic study is comparable to the biochemical findings in carriers of polymorphic allele than noncarriers, especially in NDD patients. Conclusions Pilot study indicates that the presence of APOC3 gene polymorphism is associated with pro-atherogenic dyslipidemia in nondiabetic patients and may raise risk of CHD. This information could be used for preventive strategies in NDD group that may otherwise go unnoticed.

A lipid lover’s guide to novel therapeutics for lipid and cardiovascular risk reduction

Lipids and lipoproteins are the target of many novel therapeutics and are an area with great potential for the prevention and treatment of cardiovascular disease (CVD). Reduction of low-density lipoprotein cholesterol has been the mainstay of reducing the burden of CVD, however, several other atherogenic particles have more recently come into the spotlight as potential avenues for primary and/or secondary prevention of CVD. These include triglycerides, high sensitivity C-reactive protein, apolipoprotein A, apolipoprotein C3 and lipoprotein(a). In this review, we showcase novel therapeutics to target lipid and cardiovascular risk reduction that are either in development or that have recently been approved for use. We discuss the mechanisms of action, data from clinical trials and expected effects of each therapy based on the current body of literature.