Apolipoprotein C-III Research Articles

Polymorphism in the apolipoprotein C3 gene and coronary lesions in patients with CHD

Background and Aims : The aim of our study was to evaluate the distribution of the APOC3 SstI polymorphism and its impact on the character of dyslipidemia and features of coronary lesions in Uzbek patients with unstable angina.Methods: The study included 141 patients with unstable angina pectoris (HC) class IIB (Braunwald E. et al., 1989) with LDL cholesterol> 100 mg / dL. The comparison group consisted of 50 healthy, age-matched, randomly selected individuals without clinical and instrumental signs of coronary artery disease according to the results of an exercise test. Coronary angiography was performed on an Allura CV-20 (Philips, Netherlands). Genotyping of SstI APOC3 gene polymorphism by PCR-RFLP. Alleles lacking a restriction site were designated S1, and alleles containing an SstI site were designated S2.Results: The analysis of the APOC3 SstI polymorphism revealed a significant prevalence of carriers of the S2 allele among patients with UA compared with healthy ethnic Uzbeks. Carriage of the S2 allele was associated with hypertriglyceridemia (> 230 mg / dL) (OR = 2.30, 95% CI: 1.14-4.67; χ2 = 5.485; P = 0.02) and a higher risk of three- and multivessel lesions. (OR = 2.171, 95% CI: 1.0792-4.3680; P = 0.03).Conclusions: Our results indicate that the determination of APOC3 SstI polymorphism may be a useful additional marker in assessing cardiovascular risk and indications for coronary angiography. Background and Aims : The aim of our study was to evaluate the distribution of the APOC3 SstI polymorphism and its impact on the character of dyslipidemia and features of coronary lesions in Uzbek patients with unstable angina. Methods: The study included 141 patients with unstable angina pectoris (HC) class IIB (Braunwald E. et al., 1989) with LDL cholesterol> 100 mg / dL. The comparison group consisted of 50 healthy, age-matched, randomly selected individuals without clinical and instrumental signs of coronary artery disease according to the results of an exercise test. Coronary angiography was performed on an Allura CV-20 (Philips, Netherlands). Genotyping of SstI APOC3 gene polymorphism by PCR-RFLP. Alleles lacking a restriction site were designated S1, and alleles containing an SstI site were designated S2. Results: The analysis of the APOC3 SstI polymorphism revealed a significant prevalence of carriers of the S2 allele among patients with UA compared with healthy ethnic Uzbeks. Carriage of the S2 allele was associated with hypertriglyceridemia (> 230 mg / dL) (OR = 2.30, 95% CI: 1.14-4.67; χ2 = 5.485; P = 0.02) and a higher risk of three- and multivessel lesions. (OR = 2.171, 95% CI: 1.0792-4.3680; P = 0.03). Conclusions: Our results indicate that the determination of APOC3 SstI polymorphism may be a useful additional marker in assessing cardiovascular risk and indications for coronary angiography.

Systematic pan-cancer analysis identifies APOC1 as an immunological biomarker which regulates macrophage polarization and promotes tumor metastasis

Apolipoprotein C1 (APOC1) has been found to play an essential part in proliferation and metastasis of numerous cancers, but related mechanism has not been elucidated, especially its function and role in tumor immunity. Through systematic pan-cancer analysis, we identified that APOC1 was closely associated with the infiltration of various immune cells in multiple cancers. Besides, APOC1 was significantly co-expressed with the immune checkpoints, major histocompatibility complex (MHC) molecules, chemokines and other immune-related genes. Furthermore, single-cell sequencing analysis suggested that the vast majority of APOC1 was expressed in macrophages or tumor-associated macrophages (TAMs). Additionally, the expression of APOC1 was significantly related to the prognosis of different cancers. Since APOC1 was most significantly abnormally expressed in renal cell cancer (RCC), subsequent experiments were carried out in RCC to explore the role of APOC1 in tumor immunity. The expression of APOC1 was significantly elevated in the tumor and serum of RCC patients. Besides, APOC1 was mainly expressed in the macrophage and it was closely related to the immune cell infiltration of RCC. Co-culture with RCC cells could induce the generation of TAMs with M2 phenotype which be blocked by silencing APOC1. The expression of APOC1 was elevated in the M2 or TAMs and APOC1 promoted M2 polarization of macrophages through interacting with CD163 and CD206. Furthermore, macrophages overexpressing APOC1 promoted the metastasis of RCC cells via secreting CCL5. Together, these data indicate that APOC1 is an immunological biomarker which regulates macrophage polarization and promotes tumor metastasis.

Volanesorsen to treat severe hypertriglyceridaemia: Apooled analysis of randomized controlled trials.

Patients with severe hypertriglyceridaemia (sHTG) are often refractory to lipid-lowering therapy. Apolipoprotein (Apo) CIII inhibition could be promising to treat subjects with sHTG. The antisense oligonucleotide against APOC3 mRNA volanesorsen was recently introduced to treat sHTG. We performed a systematic review and meta-analysis of RCTs on the efficacy and safety of volanesorsen as compared to placebo treatment in patients with severe HTG. Studies were systematically searched in the PubMed, Web of Science and Scopus databases according to PRISMA guidelines. The last search was performed on 7 February 2022. Four studies showed significant reduction in TG after 3months of treatment with volanesorsen as compared with placebo (MD: -73.9%; 95%CI: -93.5%, -54.2; p < .001 I2 = 89.05%; p < .001); VLDL-C level (MD: -71.0%; 95%CI: -76.6%, -65.4%; p < .001 I2 = 94.1%; p < .001); Apo-B48 level (MD: -69.03%; 95%CI: -98.59.4%, -39.47%; p < .001, I2 = 93.51%; p < .001) and Apo-CIII level (MD: -80.0%; 95%CI: -97.5%, -62.5; p < .001 I2 = 94.1%; p < .001) with an increase in HDL-C level (MD: +45.92%, 95%CI: +37.24%, +54.60%; p < .001 I2 = 94.34%; p < .001) and in LDL-C level (MD: +68.6%, 95%CI: +7.0%, +130.1%; p < .001 I2 = 96.18%; p < .001) without a significant elevation of Apo-B100 level (MD: +4.58%, 95%CI: -5.64%, +14.79%; p=.380 I2 = 95.09%; p < .001) in 139 volanesorsen patients as compared to 100 placebo-treated controls. Most of adverse events were mild and related to local injection site reactions. In patients with severe HTG, volanesorsen is associated with a significant reduction in TG, VLDL-C, Apo-B48 and non-HDL-C and increment of HDL-C as compared to placebo. Documented efficacy is accompanied by an acceptable safety profile.

Recent Updates in Hypertriglyceridemia Management for Cardiovascular Disease Prevention.

Mounting evidence continues to support the causal role of triglyceride-rich lipoproteins (TRL) in the development of atherosclerotic cardiovascular disease (ASCVD). Substantial residual ASCVD risk remains among high-risk patients who have elevated triglycerides despite reduction in low-density lipoprotein cholesterol (LDL-C) with statin therapy. Ongoing research efforts have focused on evaluating triglyceride-lowering therapies among patients with hypertriglyceridemia. The REDUCE-IT trial showed that the addition of icosapent ethyl, a highly purified form of eicosapentaenoic acid (EPA), can reduce vascular events among statin-treated individuals with elevated triglycerides who have either clinical ASCVD or diabetes plus another risk factor. Although additional evidence for EPA has emerged from other trials, conflicting results have been reported by subsequent trials that tested different omega-3 fatty acid formulations. Randomized clinical trials have not demonstrated incremental ASCVD benefit of fibrates on background of statin therapy, but fibrates are used to help prevent pancreatitis in patients with severe hypertriglyceridemia. Selective inhibitors of apolipoprotein C-III (apoC3) and angiopoietin-like protein 3 (ANGPTL3), proteins that are involved in metabolism of TRLs by regulating lipoprotein lipase, have been tested in selected patient populations and showed significant reduction in triglyceride and LDL-C levels. Statin therapy continues to be the cornerstone of pharmacologic reduction of cardiovascular risk. High-dose EPA in the form of icosapent ethyl has been demonstrated to have cardiovascular benefit on top of statins in persons with elevated triglycerides at high ASCVD risk. Ongoing clinical trials are evaluating novel selective therapies such as apoC3 and ANGPTL3 inhibitors.

New, Novel Lipid-Lowering Agents for Reducing Cardiovascular Risk: Beyond Statins.

Statins are the cornerstone of the prevention and treatment of atherosclerotic cardiovascular disease (ASCVD). However, even under optimal statin therapy, a significant residual ASCVD risk remains. Therefore, there has been an unmet clinical need for novel lipid-lowering agents that can target low-density lipoprotein cholesterol (LDL-C) and other atherogenic particles. During the past decade, several drugs have been developed for the treatment of dyslipidemia. Inclisiran, a small interfering RNA that targets proprotein convertase subtilisin/kexin type 9 (PCSK9), shows comparable effects to that of PCSK9 monoclonal antibodies. Bempedoic acid, an ATP citrate lyase inhibitor, is a valuable treatment option for the patients with statin intolerance. Pemafibrate, the first selective peroxisome proliferator-activated receptor alpha modulator, showed a favorable benefit-risk balance in phase 2 trial, but the large clinical phase 3 trial (PROMINENT) was recently stopped for futility based on a late interim analysis. High dose icosapent ethyl, a modified eicosapentaenoic acid preparation, shows cardiovascular benefits. Evinacumab, an angiopoietin-like 3 (ANGPTL3) monoclonal antibody, reduces plasma LDL-C levels in patients with refractory hypercholesterolemia. Novel antisense oligonucleotides targeting apolipoprotein C3 (apoC3), ANGPTL3, and lipoprotein(a) have significantly attenuated the levels of their target molecules with beneficial effects on associated dyslipidemias. Apolipoprotein A1 (apoA1) is considered as a potential treatment to exploit the athero-protective effects of high-density lipoprotein cholesterol (HDL-C), but solid clinical evidence is necessary. In this review, we discuss the mode of action and clinical outcomes of these novel lipid-lowering agents beyond statins.

Biochemical study of lipoprotein lipase enzyme and apo-lipoprotein-C2 in patients with and without type 2 diabetes mellitus

Type two diabetes mellitus (T2DM) is the most common type of diabetes; it is characterized by hyperglycemia in the presence of hyperinsulinemia which is produced from beta cell insulin secretory malfunction and insulin resistance. This study was designed as a case-control study and was constructed to study the effect of type 2 diabetes mellitus on lipoprotein lipase and Apo lipoprotein C2 levels among lipid profiles in type 2 diabetes. The patient's ages ranged from (40-60) years. The serum sample of all groups was collected and used to measure the level of lipoprotein lipase and Apo lipoprotein C2 by using the ELISA method and to measure lipid profile by spectrophotometer technique. All samples were collected from Merjan Medical City at Babylon/ Hilla city. The study revealed that there was a significant decrease in the levels of lipoprotein lipase in patients with type 2 diabetes mellitus compared with the control group ( P &lt; 0.001), also there was a significant increase in the levels of Apo lipoprotein C2 in the patient’s group compared with the control group ( P= 0.02).

Ameliorative effects of high intensity interval training and Lactobacillus rhamnosus GG Protect against tetracycline-induced fatty liver in rats: a gene expression profiling comparative study.

Exercise training and probiotics have been suggested as a treatment for the prevention of chronic liver damage such as non-alcoholic fatty liver disease (NAFLD). Lactobacillus rhamnosus Gorbach‐Goldin (LGG) is one of the most widely used probiotic strains that decreases liver damage. Thus, this study aims to consider the ameliorative effects of high intensity interval training (HIIT) and LGG against tetracycline-induced fatty liver in rats. Eighty male Wistar rats were randomly divided into 8 groups of (n=10 each group): control, LGG, HIIT, LGG+HIIT, NAFLD, NAFLD+LGG, NAFLD+HIIT, and NAFLD+LGG+HIIT. The rats are treated by intraperitoneal injection with 140 mg/kg−1 tetracycline, an antibiotic previously known to induce steatosis. The exercise training groups performed HIIT 5 days/week for 5 weeks. 107 colony-forming units (cfu) of LGG were gavaged for LGG groups 5 days/week for 5 weeks. Probiotic supplementation in combination with interval training significantly decreased tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) mRNA and matrix metalloproteinase-2 (MMP-2) mRNA in the liver (p<0.05), while the levels of lysosomal acid lipase (LIPA) mRNA was significantly increased compared to NAFLD group. Also, compared with NAFLD group, NAFLD+LGG, NAFLD+HIIT and NAFLD+LGG+HIIT groups showed a significant decrease in hepatic monocyte chemoattractant protein-1 (MCP-1). Compared to LGG and LGG+HIIT groups, all NAFLD groups showed a significant decrease in apolipoprotein C3 (apoc3) in liver tissue (p<0.05). The results suggested that interval exercise with LGG supplementation minimizes cell destruction and inflammation in liver tissue due to NAFLD by improving gene expression profiles.

The Effect of Cang Salak Tea Diet on Apolipoprotein C3 (ApoC3) Gene Expression on Hyperlipidemic Rats Model

Cardiovascular disease (CVD) is the leading cause of global mortality and disability. Hyperlipidemia is a major risk factor for CVD that can be controlled through medical therapy, appropriate nutrition, and lifestyle. This study aimed to identify the cang salak tea diet’s effect on the ApoC3 gene expression in a hyperlipidemia rat. 18 male Wistar rats were divided equally into three groups. A high-fat-diet-induced two groups of rats, and one group was the control. Once hyperlipidemia had been achieved, one of the two groups was treated with the cang salak tea, and one group was given a standard diet for four weeks. Authenticated rat and liver tissue were collected as a source of RNA isolation. Isolated RNA was used as a reaction template for the relative quantitation qPCR using β-actin as the housekeeping gene. The ApoC3 gene was specifically amplified with a Tm value of 82.73°C, Cq 17-19, and produced a sigmoid curve. The relative expression level of the ApoC3 gene in hyperlipidemia rats fed with the cang salak tea diet was 0.46 times significantly lower than the control (1.17) and P2 (1.32) groups. These results indicate that the cang salak tea has antihyperlipidemic properties to reduce CVD risk.

Interventional hepatic apoC-III knockdown improves atherosclerotic plaque stability and remodeling by triglyceride lowering.

Apolipoprotein C-III (apoC-III) is a critical regulator of triglyceride metabolism and correlates positively with hypertriglyceridemia and cardiovascular disease (CVD). It remains unclear if therapeutic apoC-III lowering reduces CVD risk and if the CVD correlation depends on the lipid-lowering or antiinflammatory properties. We determined the impact of interventional apoC-III lowering on atherogenesis using an apoC-III antisense oligonucleotide (ASO) in 2 hypertriglyceridemic mouse models where the intervention lowers plasma triglycerides and in a third lipid-refractory model. On a high-cholesterol Western diet apoC-III ASO treatment did not alter atherosclerotic lesion size but did attenuate advanced and unstable plaque development in the triglyceride-responsive mouse models. No lesion size or composition improvement was observed with apoC-III ASO in the lipid-refractory mice. To circumvent confounding effects of continuous high-cholesterol feeding, we tested the impact of interventional apoC-III lowering when switching to a cholesterol-poor diet after 12 weeks of Western diet. In this diet switch regimen, apoC-III ASO treatment significantly reduced plasma triglycerides, atherosclerotic lesion progression, and necrotic core area and increased fibrous cap thickness in lipid-responsive mice. Again, apoC-III ASO treatment did not alter triglyceride levels, lesion development, and lesion composition in lipid-refractory mice after the diet switch. Our findings suggest that interventional apoC-III lowering might be an effective strategy to reduce atherosclerosis lesion size and improve plaque stability when lipid lowering is achieved.

Antisense Oligonucleotides and Small Interfering RNA for the Treatment of Dyslipidemias

The burden of atherosclerotic disease worldwide necessitates implementing the treatment of its risk factors. Among them, hypercholesterolemia has a central role. In addition to conventional small organic compounds and the recently introduced monoclonal antibodies, new technologies are arising such as the antisense oligonucleotides and small interfering RNAs (siRNAs) that operate upstream, blocking the mRNA translation of the proteins specifically involved in lipid metabolism. In this review, we briefly explain the mechanisms of action of these molecules and discuss the difficulties related to their in vivo use as therapeutical agents. We go over the oligonucleotides tested in clinical trials that could potentially revolutionize the care of patients by acting on proteins involved in the lipoprotein metabolism and regulation, namely: angiopoietin-like protein 3 (ANGPTL3); lipoprotein a (Lp(a)); apolipoprotein B (Apo B); apolipoprotein C III (Apo C-III); and proprotein convertase subtilisin–kexin type 9 (PCSK9). Finally, the differences between ASOs and siRNAs, their future possible clinical applications, and the role of Inclisiran, a siRNA direct against PCSK9 to reduce LDL-C, were reviewed in detail.

RNA interference-based therapies for the control of atherosclerosis risk factors.

Atherosclerosis, characterized by lipid accumulation and chronic inflammation in the arterial wall, is the leading causes of death worldwide. The purpose of this article is to review the status of RNA interference (RNAi) based therapies in clinical trials for the treatment and prevention of atherosclerosis risk factors. There is a growing interest on using RNAi technology for the control of atherosclerosis risk factors. Current clinical trials utilizing RNAi for atherosclerosis are targeting lipid metabolism regulating genes including proprotein convertase subtilisin/kexin 9, apolipoprotein C-III, lipoprotein (a) and angiopoietin-like protein 3. Currently, three RNAi-based drugs have been approved by U.S. Food and Drug Administration, but there are several therapies in clinical trials at the moment, and potentially entering the market in near future. In addition, recent preclinical studies on regulating vascular inflammation have shown promising results. In recent years, RNAi based technologies and therapies have been intensively developed for the treatment of atherosclerosis risk factors, such as hyperlipidemia and vascular inflammation. Multiple potential therapeutic targets have emerged, and many of the reported clinical trials have already been successful in plasma lipid lowering. The scope of RNAi therapies is well recognized and recent approvals are encouraging for the treatment of cardiovascular and metabolic disorders.

Lipids, Apolipoproteins, Statins, and Intracerebral Hemorrhage: A Mendelian Randomization Study.

To investigate the causal role of lipid or apolipoprotein traits in intracerebral hemorrhage (ICH) and determine the effect of lipid-lowering interventions on the disease. Two-sample Mendelian randomization (MR) analyses were conducted to evaluate the associations of high-density lipoprotein cholesterol, low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), apolipoprotein (Apo)B and ApoA1 levels with risks for ICH, and those of LDL-C- (HMGCR, PCSK9, and NPC1L1) and TG-lowering targets (LPL and APOC3) with ICH. Increased levels of ApoB was associated with a decreased risk of overall ICH (OR 0.623, 95% CI 0.413-0.940; p=0.024) and lobar ICH (OR 0.579, 95% CI 0.342-0.979; p=0.042). The inverse relationship remained stable in multivariable MR. In addition, elevated TGs showed a causal effect on lobar ICH in multivariable MR (OR 1.600, 95% CI 1.009-2.537; p=0.046). The LDL-C-reducing genetic variation alleles at or near the HMGCR gene (mimicking the effect of statins) were predicted to increase the overall and deep ICH risk. Additionally, genetic variation at or near the APOC3 gene suggested that genetically reducing the activity of APOC3 (mimicking antisense anti-apoC3 agents) was predicted to decrease lobar ICH. Genetically predicted elevated ApoB may have a protective effect on overall ICH and lobar ICH, whereas elevated TG was associated with a higher risk of lobar ICH conditional on LDL-C and ApoB. MR analysis supports the conclusion that statins may increase the risk of overall and deep ICH independent of their lipid-lowering effect. More specific lipid-lowering targets may end up being the future. ANN NEUROL 2022;92:390-399.

Effect of olezarsen targeting APOC-III on lipoprotein size and particle number measured by NMR in patients with hypertriglyceridemia

Olezarsen is a hepatocyte-targeted, GalNAc-modified antisense oligonucleotide that decreases plasma levels of apolipoprotein C-III (apoC-III) and triglyceride-rich lipoproteins (TRLs). To define the effect of olezarsen on NMR-derived lipoprotein particle size and concentration. Patients (n=114) with or at risk for atherosclerotic cardiovascular disease and fasting triglycerides ≥200 and <500 mg/dL received olezarsen (10 or 50 mg every 4 weeks, 15 mg every 2 weeks, or 10 mg every week) or saline placebo subcutaneously for 6-12 months. NMR LipoProfile® analysis was performed in frozen EDTA plasma samples collected at baseline and at the primary analysis timepoint (PAT) at 6 months. A dose-dependent relationship was generally noted with increasing cumulative doses of olezarsen in TRL particle (TRLP), LDL particle (LDL-P) and HDL (HDL-P) particle concentrations. In the 50 mg every 4 weeks dose, compared to placebo, olezarsen resulted in a significant reduction in total TRL-P (51%, P<0.0001) with largest reductions in large-size (68%, P<0.0001) and medium-size (63%, P<0.0001) TRL-P. Total LDL-P concentration was not changed, but large LDL-P increased by 186% (p=0.0034), and small LDL-P decreased by 39% (p=0.0713). Total HDL-P concentration increased by 15% (P=0.0006), driven primarily by a 32% increase in small HDL subspecies (diameters <8.3 nm) (P=0.0008). Olezarsen results in favorable changes in lipoprotein concentration and particle size, primarily manifested by reduction in TRLs, remodeling to larger LDL particles, and increase in small HDL-P. These findings suggest that apoC-III inhibition improves the overall atherogenic risk profile.

The Regulation of Triacylglycerol Metabolism and Lipoprotein Lipase Activity.

Triacylglycerol (TG) metabolism is tightly regulated to maintain a pool of TG within circulating lipoproteins that can be hydrolyzed in a tissue-specific manner by lipoprotein lipase (LPL) to enable the delivery of fatty acids to adipose or oxidative tissues as needed. Elevated serum TG concentrations, which result from a deficiency of LPL activity or, more commonly, an imbalance in the regulation of tissue-specific LPL activities, have been associated with an increased risk of atherosclerotic cardiovascular disease through multiple studies. Among the most critical LPL regulators are the angiopoietin-like (ANGPTL) proteins ANGPTL3, ANGPTL4, and ANGPTL8, and a number of different apolipoproteins including apolipoprotein A5 (ApoA5), apolipoprotein C2 (ApoC2), and apolipoprotein C3 (ApoC3). These ANGPTLs and apolipoproteins work together to orchestrate LPL activity and therefore play pivotal roles in TG partitioning, hydrolysis, and utilization. This review summarizes the mechanisms of action, epidemiological findings, and genetic data most relevant to these ANGPTLs and apolipoproteins. The interplay between these important regulators of TG metabolism in both fasted and fed states is highlighted with a holistic view toward understanding key concepts and interactions. Strategies for developing safe and effective therapeutics to reduce circulating TG by selectively targeting these ANGPTLs and apolipoproteins are also discussed.

208-OR: Posttranslational Truncation of Apolipoproteins C1 and C2 and Plasma Lipids in Multiethnic Study of Atherosclerosis (MESA)

Apolipoproteins (apo) C1 and C2 are small interchangeable molecules that regulate lipoprotein metabolism. ApoC1 inhibits lipoprotein lipase (LPL) and stimulates reverse cholesterol transport while apoC2 activates LPL. Both exist as full-size native and minor truncated proteoforms; however, whether distribution of these apoC1 and C2 proteoforms may influence plasma lipids is largely unknown. Baseline plasma from 5,791 MESA participants was tested for truncated to native apoC1 and apoC2 ratios (apoC1’/C1; apoC2’/C2) . Total apoC1 and C2 concentrations were measured in a subset of 3,851 participants. Plasma lipids were measured for up to 6 times over 15 years. In adjusted models (Table) , higher apoC1’/C1 was associated with lower triglycerides (TG) and higher total (TC) and LDL cholesterol both at baseline and follow-up, and higher HDL at follow-up. Higher apoC2’/C2 was associated with lower TG and higher LDL at baseline, and higher baseline and follow-up TC and HDL. In contrast, the associations of total apoC1 and apoC2 concentrations with TG and HDL were largely in opposite directions of their proteoform ratios. For example, plasma TG were inversely associated with apoC1 and apoC2 truncation but positively associated with total apoC1 and apoC2 concentrations. Our data indicate a possible role of posttranslational apoC1 and apoC2 modification in regulating lipid metabolism. Disclosure J.Koska: None. J.Furtado: Research Support; Eli Lilly and Company, Pfizer Inc. S.Sinari: None. R.Mcclelland: None. D.Billheimer: None. P.Reaven: Research Support; AstraZeneca, Dexcom, Inc. Funding National Institutes of Health (R01-HL138969

349-OR: ADA President's Select Abstract: Circulating Level of DNA Methylation Near CPT1A and Long-Term Changes in Triglycerides in Response to Diet Interventions: The POUNDS Lost Trial

Background: Epigenome-wide association studies identified DNA methylation (DNAm) at several CpG sites of the carnitine palmitoyltransferase-1A (CPT1A) gene to be associated with triglycerides (TG) . However, little is known about whether the pre-treatment DNAm level at CPT1A is associated with changes in TG in response to weight-loss diet interventions. Methods: We included 673 white participants with overweight or obesity, who were randomly assigned to 1 of 4 diets varying in macronutrients components. Blood DNAm levels were profiled by a high-resolution methyl-capture sequencing at baseline. We defined the regional DNAm at CPT1A as the average methylation level over CpGs within 500 bp of the 3 TG-related DNAm sites (cg00574958, cg09737197, and cg17058475) , which were closely located. Two-year changes in TG were calculated. Linear regression models were used to examine the associations between baseline DNAm at CPT1A and 2-year changes in TG. Results: Higher regional DNAm level at CPT1A was associated with lower TG at baseline (β=-2.21, SE=1.01, p=0.029) . We found that dietary fat intake significantly modified the association between baseline DNAm at CPT1A and 2-year changes in TG, independent of concurrent weight-loss (p-int=0.018) . In the low-fat diet group, a higher regional DNAm level was associated with a greater reduction in TG at 2 years, after adjustment for age, sex, baseline body mass index, use of lipid-lowering medication, baseline TG level, and concurrent weight-loss (p=0.01) , whereas no such association was observed in the high-fat diet group (p=0.64) . A similar interaction pattern was also found between dietary fat and baseline DNAm at CPT1A on 2-year changes of TG in very-low-density lipoprotein without apolipoprotein C-III (p-int=0.01) . Conclusion: Our data indicate that participants with a higher regional DNAm level at CPT1A benefited more in long-term improvement in TG when assigned a low-fat weight-loss diet. Disclosure X.Li: None. X.Shao: None. Q.Xue: None. E.Grundberg: None. G.Bray: None. F.Sacks: None. L.Qi: None. Funding The study was supported by grants from the National Heart, Lung, and Blood Institute (HL071981, HL034594, HL126024) , the National Institute of Diabetes and Digestive and Kidney Diseases (DK115679, DK091718, DK100383) , the Fogarty International Center (TW010790) , and Tulane Research Centers of Excellence Awards. Xiang Li was the recipient of the American Heart Association Predoctoral Fellowship Award (19PRE34380036) .

207-OR: ADA Presidents' Select Abstract: Apolipoprotein C-III Proteoforms and Their Relationships with Plasma Lipids and Cardiovascular Events in Multiethnic Study of Atherosclerosis (MESA)

Apolipoprotein C-III (apoC-III) exists in four major proteoforms - unglycosylated form (C-III0a) , and glycosylated forms with zero (C-III0b) , one (C-III1, most abundant) or two (C-III2) sialic acids - which modify lipoprotein metabolism. The relation of these proteoforms with plasma lipids and cardiovascular disease (CVD) risk in a general population is unknown. Total apoC-III concentrations and apoC-III proteoforms were measured in baseline plasma of 5,787 MESA participants. Plasma lipids and CVD risk were assessed over 15 years. Proteoform percentages correlated modestly with total apoC-III (r2&amp;lt;0.10) . ApoC-III0b decreased and C-III2 increased with age (by 11% per 5 yrs) . Compared to non-Hispanic whites, African Americans had lower (35%) total apoC-III and C-III0b and higher C-III2 (88%) , and Chinese Americans and Hispanics had higher C-III0a (88%; 40%) . Females had higher total apoC-III, C-III1 and C-III0b (23%; 31%; 30%) , and lower C-III0a and C-III2 (17%; 28%) . Total apoC-III, C-III0b, C-III1 and C-III2 were higher in diabetes. Prospectively, in models that included baseline characteristics, lipid-lowering medications and total apoC-III, higher C-III2 to C-III1 ratio (C-III2/III1) was associated with lower triglycerides (22%) and higher HDL (19%) . After adjustment for baseline characteristics (including lipids) and total apoC-III, higher C-III0b to C-III1 ratio was associated with reduced risk of CVD (n=629 events, HR= 0.89) and coronary heart disease (n=426, HR=0.86) . In contrast, despite links with better lipids, higher C-III2/III1 was associated with increased risk of CVD (HR=1.09) . No CVD events were related to total apoC-III. Our data indicate differences in clinical and demographic determinants of total apoC-III concentrations and apoC-III proteoforms and highlight the importance of apoC-III proteoform distribution in predicting future lipid concentrations and CVD risk. Disclosure J.Koska: None. S.Sinari: None. Y.Hu: None. J.Furtado: Research Support; Eli Lilly and Company, Pfizer Inc. D.Billheimer: None. D.Nedelkov: None. R.Mcclelland: None. P.Reaven: Research Support; AstraZeneca, Dexcom, Inc. Funding National Institutes of Health (R01-HL138969)

Prolonged Fasting Alters the Size, Function, and Glycoproteomic Profile of HDL Particles

ObjectivesTo investigate the effects of a single 36-hour fast on HDL glycoproteomic composition on isolated HDL particles. MethodsWe obtained plasma from a previous study where 20 healthy subjects, age 20–40, fasted for 36 hours. HDL was isolated using density-based ultracentrifugation steps, followed by size-exclusion chromatography. Glycoproteomic was analyzed using a targeted LC-MS/MS method, and lipoprotein particle size distribution analysis using nuclear magnetic resonance (NMR) spectroscopy. ResultsHDL-associated apolipoprotein A-IV (ApoA-IV) content was significantly reduced (8918.39 +/– 3823.39 normalized ion counts vs 3690.82 +/– 2147.29 normalized ion count, p adjusted < 0.0001), suggesting a reduction in intestinally-derived HDL after a 36-hour fast. HDL associated apolipoprotein C-III (ApoC-III) di-sialylated glycopeptides decreased in HDL following a 36-hour fast compared to an overnight 12-hour fast (0.1680 +/– 0.0342 normalized ion counts vs 0.1315 +/– 0.0373 normalized ion counts, p adjusted = 0.041). Additionally, particle size distribution analysis showed an increase in abundance of calibrated large HDL of size 9.6–13nm (3.42 +/– 2.218 μmol/L vs 3.885 +/– 2.134 μmol/L, p adjusted = 0.011) and a decrease in abundance of medium HDL of size 8.1–9.5nm (6.88 +/– 1.86 μmol/L vs 5.82 +/– 2.048 μmol/L, p adjusted = 0.019) after a 36-hour fast. There were no significant changes in LDL particle size (21.115 +/– nm s 21.205 +/– 0.458 nm, p adjusted = 0.655) but there was a significant increase in overall calibrated LDL particle concentration (1138.05 +/– 357.94 μmol/L vs 1262.3 +/– 313.33 μmol/L, p adjusted = 0.011) and calibrated small LDL particle concentration (454.85 +/– 187.76 μmol/L vs 598.8 +/– 190.84 μmol/L, p adjusted = 0.025). ConclusionsOur findings indicate that prolonged fasting alters lipoprotein profiles by affecting the proportions of large and small HDL and LDL particles, as well as altering the protein composition of HDL particles, specifically by reducing the abundance of ApoA-IV, which suggests a reduction in the contribution of intestinally-derived HDL particles to the circulating HDL pool. Future studies are needed to determine the long-term effects of multiple bouts of prolonged fasting. Funding SourcesUniversity of California Davis, National Institute on Aging.

Apolipoprotein C-III is linked to the insulin resistance and beta-cell dysfunction that are present in rheumatoid arthritis

BackgroundInsulin resistance and beta-cell dysfunction are manifestations of rheumatoid arthritis (RA). Apolipoprotein C-III (ApoC3) has been associated with such insulin resistance and beta-cell dysfunction in the general population. Our purpose was to study whether ApoC3 is also related to the insulin resistance and beta-cell dysfunction that are present in patients with RA.MethodsThree hundred thirty-eight non-diabetic patients with RA who had a glycemia lower than 110 mg/dl were recruited. Insulin, C-peptide, and ApoC3 were assessed. Insulin resistance and beta-cell function were calculated using the Homeostasis Model Assessment (HOMA2) indices. A multivariable regression analysis was performed to study the relationship of ApoC3 with those molecules and indices adjusting for classic factors associated with insulin resistance that included glucocorticoids.ResultsApoC3 was related to significant higher levels of circulating insulin (beta coef. 0.37 [95%CI 0.01–0.73] µU/ml, p = 0.044) and C-peptide (beta coef. 0.13 [95%CI 0.05–0.22] ng/ml, p = 0.003), and higher insulin resistance —HOMA2-IR— (beta coef. 0.05 [95%CI 0.00–0.09], p = 0.041) and beta-cell dysfunction —HOMA2-%B— (beta coef. 2.94 [95%CI 0.07–5.80], p = 0.044) indices. This was found after a fully multivariable analysis that included, among others, prednisone intake and the classic factors associated with carbohydrate metabolism such as triglycerides, waist circumference, and obesity.ConclusionApoC3, insulin resistance, and beta-cell dysfunction are independently associated in patients RA.

Complex association of apolipoprotein E-containing HDL with coronary artery disease burden in cardiovascular disease.

BackgroundAlthough traditional lipid parameters and coronary imaging techniques are valuable for cardiovascular disease (CVD) risk prediction, better diagnostic tests are still needed.MethodsIn a prospective, observational study, 795 individuals had extensive cardiometabolic profiling, including emerging biomarkers, such as apolipoprotein E–containing HDL-cholesterol (ApoE-HDL-C). Coronary artery calcium (CAC) score was assessed in the entire cohort, and quantitative coronary computed tomography angiography (CCTA) characterization of total burden, noncalcified burden (NCB), and fibrous plaque burden (FB) was performed in a subcohort (n = 300) of patients stratified by concentration of ApoE-HDL-C. Total and HDL-containing apolipoprotein C-III (ApoC-III) were also measured.ResultsMost patients had a clinical diagnosis of coronary artery disease (CAD) (n = 80.4% of 795), with mean age of 59 years, a majority being male (57%), and about half on statin treatment. The low ApoE-HDL-C group had more severe stenosis (11% vs. 2%, overall P < 0.001), with higher CAC as compared with high ApoE-HDL-C. On quantitative CCTA, the high ApoE-HDL-C group had lower NCB (β = –0.24, P = 0.0001), which tended to be significant in a fully adjusted model (β = –0.32, P = 0.001) and altered by ApoC-III in HDL levels. Low ApoE-HDL-C was significantly associated with LDL particle number (β = 0.31; P = 0.0001). Finally, when stratified by FB, ApoC-III in HDL showed a more robust predictive value of CAD over ApoE-HDL-C (AUC: 0.705, P = 0.0001) in a fully adjusted model.ConclusionApoE-containing HDL-C showed a significant association with early coronary plaque characteristics and is affected by the presence of ApoC-III, indicating that low ApoE-HDL-C and high ApoC-III may be important markers of CVD severity.Trial RegistrationClinicalTrials.gov: NCT01621594.FundingThis work was supported by the NHLBI at the NIH Intramural Research Program.