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BackgroundHeparanase is the major enzyme involved in degradation of endothelial heparan sulfates, which is associated with impaired endothelial nitric oxide synthesis. However, the effect of heparan sulfate chain length in relation to endothelial function and nitric oxide availability has never been investigated. We studied the effect of heterozygous mutations in heparan sulfate elongation genes EXT1 and EXT2 on endothelial function in vitro as well as in vivo.Methods and resultFlow-mediated dilation, a marker of nitric oxide bioavailability, was studied in Ext1(+/-) and Ext2(+/-) mice versus controls (n=7 per group), as well as in human subjects with heterozygous loss of function mutations in EXT1 and EXT2 (n=13 hereditary multiple exostoses and n=13 controls). Endothelial function was measured in microvascular endothelial cells under laminar flow with or without siRNA targeting EXT1 or EXT2. Endothelial glycocalyx and maximal arteriolar dilatation were significantly altered in Ext1(+/-) and Ext2(+/-) mice compared to wild-type littermates (glycocalyx: wild-type 0.67±0.1 μm, Ext1(+/-) 0.28±0.1 μm and Ext2(+/-) 0.25±0.1 μm, P

Alexander Sekita,1 Harald Unterweger,1 Sonja Berg,1 Sabine Ohlmeyer,2 Tobias Bäuerle,3 Kang H Zheng,4 Bram F Coolen,5 Aart J Nederveen,6 Claudia Cabella,7 Silvia Rossi,7 Erik SG Stroes,4 Christoph Alexiou,1 Stefan Lyer,1,* Iwona Cicha1,* 1ENT-Department, Section of Experimental Oncology Und Nanomedicine (SEON), Else Kröner-Fresenius-Stiftung-Professorship, Universitätsklinikum Erlangen, Erlangen, Germany; 2Institute of Radiology, Universitätsklinikum Erlangen, Erlangen, Germany; 3Preclinical Imaging Platform Erlangen (PIPE), Universitätsklinikum Erlangen, Erlangen, Germany; 4Department of Vascular Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, the Netherlands; 5Department of Biomedical Engineering and Physics, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, the Netherlands; 6Department of Radiology and Nuclear Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, the Netherlands; 7Bracco Imaging SpA, Centro Ricerche Bracco, Colleretto Giacosa, Turin, Italy*These authors contributed equally to this workCorrespondence: Iwona Cicha, Universitätsklinikum Erlangen, Glückstr, 10a, Erlangen, 91054, Germany, Tel +49 9131 85 43953, Fax +49 9131 85 34828, Email Iwona.Cicha@uk-erlangen.dePurpose: In this study, a detailed characterization of a rabbit model of atherosclerosis was performed to assess the optimal time frame for evaluating plaque vulnerability using superparamagnetic iron oxide nanoparticle (SPION)-enhanced magnetic resonance imaging (MRI).Methods: The progression of atherosclerosis induced by ballooning and a high-cholesterol diet was monitored using angiography, and the resulting plaques were characterized using immunohistochemistry and histology. Morphometric analyses were performed to evaluate plaque size and vulnerability features. The accumulation of SPIONs (novel dextran-coated SPIONDex and ferumoxytol) in atherosclerotic plaques was investigated by histology and MRI and correlated with plaque age and vulnerability. Toxicity of SPIONDex was evaluated in rats.Results: Weak positive correlations were detected between plaque age and intima thickness, and total macrophage load. A strong negative correlation was observed between the minimum fibrous cap thickness and plaque age as well as the mean macrophage load. The accumulation of SPION in the atherosclerotic plaques was detected by MRI 24 h after administration and was subsequently confirmed by Prussian blue staining of histological specimens. Positive correlations between Prussian blue signal in atherosclerotic plaques, plaque age, and macrophage load were detected. Very little iron was observed in the histological sections of the heart and kidney, whereas strong staining of SPIONDex and ferumoxytol was detected in the spleen and liver. In contrast to ferumoxytol, SPIONDex administration in rabbits was well tolerated without inducing hypersensitivity. The maximum tolerated dose in rat model was higher than 100 mg Fe/kg.Conclusion: Older atherosclerotic plaques with vulnerable features in rabbits are a useful tool for investigating iron oxide-based contrast agents for MRI. Based on the experimental data, SPIONDex particles constitute a promising candidate for further clinical translation as a safe formulation that offers the possibility of repeated administration free from the risks associated with other types of magnetic contrast agents.Keywords: atherosclerosis, plaque vulnerability, rabbit model, macrophages, histology, tissue iron, SPION-enhanced MRI

Objective A positive family history of premature coronary artery disease (CAD) is a risk factor for cardiovascular disease (CVD), independent of traditional risk factors. Therefore, currently used risk algorithms poorly predict risk in these individuals. Novel methods are thus needed to assess cardiovascular risk. Pulse-wave velocity (PWV) might be such a method, but it is unknown whether PWV is increased in first-degree relatives of patients with premature CAD. Design Observational case-control study. Setting Academic hospital. Patients Patients with premature CAD and a positive family history of premature CVD (n=50), their first-degree relatives without CVD (n=50) and unrelated controls (n=50). Interventions None. Main Outcome Measures PWV was measured with using an Arteriograph system. Differences in PWV were assessed by a generalised linear model and multinomial logistic regression. Results Patients with premature CAD had a higher PWV compared with first-degree relatives and controls (9.69±2.90 m/s vs 8.15±1.96 m/s and 7.38±1.08 m/s; p<0.05 patients vs all groups). Linear regression showed all groups related to PWV, with patients having the highest PWV and controls the lowest (p<0.0001). Furthermore, PWV was associated with first-degree relatives (OR 1.32, 95% CI 1.02 to 1.72; p<0.05) and premature CAD (OR 1.72, 95% CI 1.32 to 2.24; p<0.05) compared with controls. These findings were independent of blood pressure and other traditional risk factors. Conclusions Patients with premature CAD and their first-degree relatives had higher PWV compared with controls, independent of other risk factors. This holds promise for the future, in which arterial stiffness might play a role in risk prediction within families with premature CAD. [ABSTRACT FROM AUTHOR]

Rationale: Recent clinical and preclinical studies have demonstrated that systemic lupus erythematosus (SLE) is associated with an increased risk for cardiovascular disease (CVD). However, unlike in the general population, little is known regarding the efficacy of atheroprotective interventions in patients with SLE. The current study aims to determine the benefit of lymphocyte inhibition on reducing the atherosclerotic burden in SLE-susceptible LDLr-deficient mice.Methods: Female LDLr(-/-) mice were lethally irradiated and reconstituted with bone marrow from C57Bl/6 mice (LDLr.B6) or the SLE-susceptible B6.Sle1.2.3 mice (LDLr.Sle). At 16 weeks post transplant, mice were treated with atorvastatin (10 mg/kg), mycophenolate mofetil (MMF; 40 mg/kg), or both (MMF-A) for 8 weeks, after which the extent of atherosclerosis and the presence of SLE were assessed.Results: Following 8 weeks of treatment, we observed that atorvastatin-mediated reduction in cholesterol levels attenuated atherogenesis in LDLr.B6 mice but failed to significantly reduce atherosclerotic lesion size in LDLr.Sle mice, in spite of a significant reduction in serum cholesterol levels. Treatment with MMF and MMF-A attenuated atherogenesis in LDLr.B6 and LDLr.Sle mice. In addition, MMF-containing regimens inhibited recruitment of CD4+ T cells to atherosclerotic lesions in LDLr.Sle mice. In these mice, MMF also reduced the proportion of activated splenic T cells, as well as interleukin 10 secretion by T cells. With regard to lupus activity, MMF had no overt effect on anti-double-stranded DNA (dsDNA) antibody titres or kidney function and pathology.Conclusions: The current study demonstrates that reduction of cholesterol levels alone is not atheroprotective in lupus-mediated atherogenesis. This is the first study to demonstrate that MMF reduces the atherosclerotic burden in a model of lupus-accelerated atherosclerosis. Our results suggest that MMF treatment may prove beneficial in preventing CVD in patients with SLE. [ABSTRACT FROM AUTHOR]

Objective: Abnormal cellular cholesterol handling in islets may contribute to beta-cell dysfunction in type 2 diabetes. beta-Cell deficiency for the ATP binding cassette transporter A1 (ABCA1), which mediates the efflux of cellular cholesterol, leads to altered intracellular cholesterol homeostasis and impaired insulin secretion in mice. We aimed to assess the impact of ABCA1 dysfunction on glucose homeostasis in humans.Research Design and Methods: In heterozygous carriers of disruptive mutations in ABCA1 and family-based noncarriers of similar age, sex, and BMI, we performed oral glucose tolerance tests (OGTTs) (n = 15 vs. 14) and hyperglycemic clamps (n = 8 vs. 8).Results: HDL cholesterol levels in carriers were less than half those in noncarriers, but LDL cholesterol levels did not differ. Although fasting plasma glucose was similar between groups, glucose curves after an OGTT were mildly higher in carriers than in noncarriers. During hyperglycemic clamps, carriers demonstrated lower first-phase insulin secretion than noncarriers but no difference in insulin sensitivity. The disposition index (a measure of beta-cell function adjusted for insulin sensitivity) of the carriers was significantly reduced in ABCA1 heterozygotes.Conclusions: Carriers of loss-of-function mutations in ABCA1 show impaired insulin secretion without insulin resistance. Our data provide evidence that ABCA1 is important for normal beta-cell function in humans. [ABSTRACT FROM AUTHOR]

Background. The objective of the present study was to assess whether the high-density lipoprotein cholesterol (HDL-c)-increasing effect of nevirapine (NVP), as observed in human immunodeficiency virus type 1 (HIV-1)-infected subjects, at least in part may relate to intrinsic properties of NVP.Methods. At 2, 6, and 12 weeks after birth, complete lipid profiles as well as plasma apolipoproteins levels were assessed in 80 HIV-uninfected newborns, half of whom received NVP and half lamivudine (3TC), respectively. Newborns were randomly selected from a randomized trial in which NVP or 3TC had been administered to HIV-uninfected infants born to HIV-infected mothers to try and prevent HIV-1 transmission from occurring during breast-feeding.Results. After 6 weeks of therapy, the expected physiological decline in HDL-c levels in the newborns was attenuated in infants treated with NVP, compared with levels in those treated with 3TC. Apolipoprotein A-I (apoA-I) levels were higher at all time points in the NVP arm than they were in the 3TC arm (P=.02), reaching peak levels at 6 weeks. The difference in HDL-c was no longer significant at 12 weeks.Conclusions. apoA-I levels and HDL-c were elevated in HIV-1-uninfected newborns receiving NVP, compared with those receiving 3TC. These data support that NVP may indeed have intrinsic apoA-I and HDL-c elevating properties in humans. Copyright © 2007 Infectious Diseases Society of America [ABSTRACT FROM AUTHOR]

Objective: To evaluate the safety and tolerability of prolonged-release nicotinic acid (Niaspan) added to statin therapy in patients at increased cardiovascular risk.Methods: This was a 6-month, prospective, observational, multicentre, open-label evaluation of prolonged-release nicotinic acid (maximum dose 2000 mg/day) in statin-treated patients with cardiovascular disease and/or type 2 diabetes. The primary endpoint was the safety and tolerability of prolonged-release nicotinic acid, with special regard to treatment-related adverse drug reactions (ADRs). Secondary endpoints were changes in lipids and 10-year cardiovascular risk (Prospective Cardiovascular Münster (PROCAM) score).Results: The study population included 1053 patients: 50% had hypertension, diabetes and/or metabolic syndrome (National Cholesterol Education Program/Adult Treatment Panel III criteria) and 80% had cardiovascular disease. Flushing (mostly mild or moderate) occurred in 430 patients (40.8%). Other ADRs occurred in 125 patients (12.5%), most commonly pruritus (2.7%), gastro-intestinal symptoms (3.8%) and nervous system-related complaints (3.8%). Serious ADRs were uncommon (0.6%). All patients recovered completely from these ADRs after treatment discontinuation. In total, 11.1% of the patients discontinued study medication for flushing and 8.4% for other ADRs. There was no evidence of hepatotoxicity or myopathy. New-onset hyperglycaemia was negligible. Overall tolerability of prolonged-release nicotinic acid treatment (n = 734 patients at closeout) was 'very good' in 130 (17.7%), 'good' in 262 (35.7%), and 'acceptable' in 144 (19.6%) patients. High-density lipoprotein (HDL) cholesterol increased by 23%, triglycerides decreased by 15% and LDL-C decreased by 4%.Conclusions: Prolonged-release nicotinic acid was safe and generally well tolerated and effective in combination with statin therapy in patients at high risk of cardiovascular events, with a side-effect profile consistent with previous clinical experience. [ABSTRACT FROM AUTHOR]

Objectives: This study was designed to test the hypothesis that at any low-density lipoprotein cholesterol (LDL-C) level, other lipid parameters such as non-high-density lipoprotein cholesterol (HDL-C) levels, triglyceride (TG) levels, and the total cholesterol (TC)/HDL-C are still associated with an increased coronary heart disease (CHD) risk.Background: Although LDL-C is considered to be the primary target of lipid-lowering therapy, other parameters of the lipoprotein-lipid profile may more closely associated with CHD risk.Methods: In the EPIC (European Prospective Investigation Into Cancer and Nutrition)-Norfolk prospective population study, 21,448 participants without diabetes or CHD between age 45 and 79 years were followed for 11.0 years. A total of 2,086 participants developed CHD during follow-up.Results: Among individuals with low LDL-C levels (<100 mg/dl), after adjustment for age, sex, smoking, systolic blood pressure, waist circumference, physical activity, and hormone replacement therapy (in women), those with non-HDL-C >130 mg/dl had a hazard ratio (HR) for future CHD of 1.84 (95% confidence interval [CI]: 1.12 to 3.04) when compared with those with non-HDL-C levels <130 mg/dl. In a similar model, individuals with TG levels >150 mg/dl had an HR of 1.63 (95% CI: 1.02 to 2.59) when compared with those with TG levels <150 mg/dl, and individuals with a TC/HDL-C ratio >5 had an HR of 2.19 (95% CI: 1.22 to 3.93) when compared with those with a TC/HDL-C ratio <5.Conclusions: In this prospective study, independently of their plasma LDL-C levels, participants with high non-HDL-C levels, high TG levels, or with an elevated TC/HDL-C ratio were at increased CHD risk. CHD risk assessment algorithms as well as lipid targets of lipid-lowering trials may also need to consider other easily available parameters such as non-HDL-C. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to investigate the role of reduced lecithin: cholesterol acyltransferase (LCAT) function on atherogenesis using 3.0-T carotid magnetic resonance imaging (MRI) and B-mode ultrasound. Background: The role of low high-density lipoprotein cholesterol as a causal factor in atherogenesis has recently been questioned. LCAT plays a key role in high-density lipoprotein cholesterol metabolism. Methods: Carotid 3.0-T MRI and B-mode ultrasound measurements were performed in 40 carriers of LCAT gene mutations and 40 controls, matched for age. Patients with cardiovascular disease were excluded. Results: Carriers had 31% lower LCAT activity levels and 38% decreased high-density lipoprotein cholesterol levels (both p < 0.001 vs. controls). Carriers presented with a 10% higher normalized wall index (0.34 ± 0.07 vs. 0.31 ± 0.04, p = 0.002), a 22% higher mean wall area (17.3 ± 8.5 mm(2) vs. 14.2 ± 4.1 mm(2), p = 0.01), and a 22% higher total wall volume (1,039 ± 508 mm(3) vs. 851 ± 247 mm(3), p = 0.01 vs. controls) as measured by MRI. The prevalence (20 vs. 5, p = 0.002) and the total volume (102 mm(3) vs. 3 mm(3)) of atherosclerotic plaque components on MRI relating to lipid-rich tissue or calcification were also higher in carriers than in controls. All differences retained significance after adjustment for age, sex, blood pressure, low-density lipoprotein cholesterol, body mass index, smoking, and family history of cardiovascular disease. Common carotid intima-media thickness measured with ultrasound was increased in carriers by 12.5% (0.72 ± 0.33 mm vs. 0.64 ± 0.15 mm, p = 0.14). Conclusions: Carriers of LCAT gene mutations exhibit increased carotid atherosclerosis, indicating an increased risk of cardiovascular disease. The present findings imply that increasing LCAT activity may be an attractive target in cardiovascular prevention strategies. [ABSTRACT FROM AUTHOR]

Purpose of Review: Lipoprotein (a) [Lp(a)] is a likely causal risk factor for atherosclerotic cardiovascular disease (ASCVD) and aortic valve disease, confirmed by Mendelian randomization. With reliable assays, it has been established that Lp(a) is linearly associated with ASCVD. Current low-density lipoprotein cholesterol (LDL-C) lowering therapies do not or minimally lower Lp(a). This review focuses on the clinical importance and therapeutic consequences of Lp(a) measurement., Recent Findings: Development of RNA-based Lp(a) lowering therapeutics has positioned Lp(a) as one of the principal residual risk factors to target in the battle against lipid-driven ASCVD risk. Pelacarsen, which is a liver-specific antisense oligonucleotide, has shown Lp(a) reductions up to 90% and its phase 3 trial is currently underway. Olpasiran is a small interfering RNA targeting LPA messenger RNA, which is being investigated in phase 2 and has already shown dose-dependent Lp(a) reductions up to 90%., Summary: Lp(a) should be measured in every patient at least once to identify patients with very high Lp(a) levels. These patients could benefit from Lp(a) lowering therapies when approved. In the meantime, therapy in high Lp(a) patients should focus on further reducing LDL-C and other ASCVD risk factors., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Peripheral ischemia caused by peripheral artery disease is associated with systemic inflammation, which may aggravate underlying comorbidities such as atherosclerosis and heart failure. However, the mechanisms of increased inflammation and inflammatory cell production in patients with peripheral artery disease remain poorly understood., Methods: We used peripheral blood collected from patients with peripheral artery disease and performed hind limb ischemia (HI) in Apoe -/- mice fed a Western diet and C57BL/6J mice with a standard laboratory diet. Bulk and single-cell RNA sequencing analysis, whole-mount microscopy, and flow cytometry were performed to analyze hematopoietic stem and progenitor cell (HSPC) proliferation, differentiation, and relocation., Results: We observed augmented numbers of leukocytes in the blood of patients with peripheral artery disease and Apoe -/- mice with HI. RNA sequencing and whole-mount imaging of the bone marrow revealed HSPC migration into the vascular niche from the osteoblastic niche and their exaggerated proliferation and differentiation. Single-cell RNA sequencing demonstrated alterations in the genes responsible for inflammation, myeloid cell mobilization, and HSPC differentiation after HI. Heightened inflammation in Apoe -/- mice after HI aggravated atherosclerosis. Surprisingly, bone marrow HSPCs expressed higher amounts of the receptors for IL (interleukin)-1 and IL-3 after HI. Concomitantly, the promoters of Il1r1 and Il3rb had augmented H3K4me3 and H3K27ac marks after HI. Genetic and pharmacological inhibition of these receptors resulted in suppressed HSPC proliferation, reduced leukocyte production, and ameliorated atherosclerosis., Conclusions: Our findings demonstrate increased inflammation, HSPC abundance in the vascular niches of the bone marrow, and elevated IL-3Rb and IL-1R1 (IL-1 receptor 1) expression in HSPC following HI. Furthermore, the IL-3Rb and IL-1R1 signaling plays a pivotal role in HSPC proliferation, leukocyte abundance, and atherosclerosis aggravation after HI., Competing Interests: Disclosures None.

Aim: To compare LDL-C concentrations using the Friedewald formula, the Martin-Hopkins formula, a direct assay and polyacrylamide gradient gel electrophoresis (PGGE) to the reference standard density gradient ultracentrifugation in patients with Familial Dysbetalipoproteinemia (FD) patients. We also compared non-HDL-cholesterol concentrations by two methods., Methods: For this study data from 28 patients with genetically confirmed FD from the placebo arm of the EVOLVE-FD trial were used. Four different methods for determining LDL-C were compared with ultracentrifugation. Non-HDL-C was measured with standard assays and compared to ultracentrifugation. Correlation coefficients and Bland-Altman plots were used to compare the methods., Results: Mean age of the 28 FD patients was 62 ± 9 years, 43 % were female and 93 % had an ɛ2ɛ2 genotype. LDL-C determined by Friedewald (R 2 = 0.62, p <0.01), Martin-Hopkins (R 2 = 0.50, p = 0.01) and the direct assay (R 2 = 0.41, p = 0.03) correlated with density gradient ultracentrifugation. However, Bland-Altman plots showed considerable over- or underestimation by the four methods compared to ultracentrifugation. Non-HDL-C showed good correlation and agreement., Conclusion: In patients with FD, all four methods investigated over- or underestimated LDL-C concentrations compared with ultracentrifugation. In contrast, standard non-HDL-C assays performed well, emphasizing the use of non-HDL-C in patients with FD., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: BEH declares no conflicts of interest. CK declares no conflicts of interest. JRvL has received a research grant by Amryt. Ad-board speaker fees have been paid to institution of ES by: Amgen, Sanofi, Esperion, Novo-Nordisk, Akcea/Ionis, Regeneron. NR declares no conflict of interest. MM declares no conflicts of interest LvZ declares no conflicts of interest. DMB declares no conflict of interest. ADM declares no conflict of interest. FV declares no conflict of interest., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)

Importance: Lipoprotein(a) (Lp[a]) is an important risk factor for atherothrombotic cardiovascular disease and aortic stenosis, for which there are no treatments approved by regulatory authorities., Objectives: To assess adverse events and tolerability of a short interfering RNA (siRNA) designed to reduce hepatic production of apolipoprotein(a) and to assess associated changes in plasma concentrations of Lp(a) at different doses., Design, Setting, and Participants: A single ascending dose study of SLN360, an siRNA targeting apolipoprotein(a) synthesis conducted at 5 clinical research unit sites located in the US, United Kingdom, and Australia. The study enrolled adults with Lp(a) plasma concentrations of 150 nmol/L or greater at screening and no known clinically overt cardiovascular disease. Participants were enrolled between November 18, 2020, and July 21, 2021, with last follow-up on December 29, 2021., Interventions: Participants were randomized to receive placebo (n = 8) or single doses of SLN360 at 30 mg (n = 6), 100 mg (n = 6), 300 mg (n = 6), or 600 mg (n = 6), administered subcutaneously., Main Outcomes and Measures: The primary outcome was evaluation of safety and tolerability. Secondary outcomes included change in plasma concentrations of Lp(a) to a maximum follow-up of 150 days., Results: Among 32 participants who were randomized and received the study intervention (mean age, 50 [SD, 13.5] years; 17 women [53%]), 32 (100%) completed the trial. One participant experienced 2 serious adverse event episodes: admission to the hospital for headache following SARS-CoV-2 vaccination and later for complications of cholecystitis, both of which were judged to be unrelated to study drug. Median baseline Lp(a) concentrations were as follows: placebo, 238 (IQR, 203-308) nmol/L; 30-mg SLN360, 171 (IQR, 142-219) nmol/L; 100-mg SLN360, 217 (IQR, 202-274) nmol/L; 300-mg SLN360, 285 (IQR, 195-338) nmol/L; and 600-mg SLN360, 231 (IQR, 179-276) nmol/L. Maximal median changes in Lp(a) were -20 (IQR, -61 to 3) nmol/L, -89 (IQR, -119 to -61) nmol/L, -185 (IQR, -226 to -163) nmol/L, -268 (IQR, -292 to -189) nmol/L, and -227 (IQR, -270 to -174) nmol/L, with maximal median percentage changes of -10% (IQR, -16% to 1%), -46% (IQR, -64% to -40%), -86% (IQR, -92% to -82%), -96% (IQR, -98% to -89%), and -98% (IQR, -98% to -97%), for the placebo group and the 30-mg, 100-mg, 300-mg, and 600-mg SLN360 groups, respectively. The duration of Lp(a) lowering was dose dependent, persisting for at least 150 days after administration., Conclusions and Relevance: In this phase 1 study of 32 participants with elevated Lp(a) levels and no known cardiovascular disease, the siRNA SLN360 was well tolerated, and a dose-dependent lowering of plasma Lp(a) concentrations was observed. The findings support further study to determine the safety and efficacy of this siRNA., Trial Registration: ClinicalTrials.gov Identifier: NCT04606602; EudraCT Identifier: 2020-002471-35.

Importance: Lipid management typically focuses on levels of low-density lipoprotein cholesterol (LDL-C) and, to a lesser extent, triglycerides (TG). However, animal models and genetic studies suggest that the atherogenic particle subpopulations (LDL and very-low-density lipoprotein [VLDL]) are both important and that the number of particles is more predictive of cardiac events than their lipid content., Objective: To determine whether common measures of cholesterol concentration, TG concentration, or their ratio are associated with cardiovascular risk beyond the number of apolipoprotein B (apoB)-containing lipoproteins., Design, Setting, and Participants: This prospective cohort analysis included individuals from the population-based UK Biobank and from 2 large international clinical trials, FOURIER and IMPROVE-IT. The median (IQR) follow-up was 11.1 (10.4-11.8) years in UK Biobank and 2.5 (2.0-4.7) years in the clinical trials. Two populations were studied in this analysis: 389 529 individuals in the primary prevention group who were not taking lipid-lowering therapy and 40 430 patients with established atherosclerosis who were receiving statin treatment., Exposures: ApoB, non-high-density lipoprotein cholesterol (HDL-C), LDL-C, and TG., Main Outcome and Measures: The primary study outcome was incident myocardial infarction (MI)., Results: Of the 389 529 individuals in the primary prevention group, 224 097 (58%) were female, and the median (IQR) age was 56.0 (49.5-62.5) years. Of the 40 430 patients with established atherosclerosis, 9647 (24%) were female, and the median (IQR) age was 63 (56.2-69.0) years. In the primary prevention cohort, apoB, non-HDL-C, and TG each individually were associated with incident MI. However, when assessed together, only apoB was associated (adjusted hazard ratio [aHR] per 1 SD, 1.27; 95% CI, 1.15-1.40; P < .001). Similarly, only apoB was associated with MI in the secondary prevention cohort. Adjusting for apoB, there was no association between the ratio of TG to LDL-C (a surrogate for the ratio of TG-rich lipoproteins to LDL) and risk of MI, implying that for a given concentration of apoB-containing lipoproteins, the relative proportions of particle subpopulations may no longer be a predictor of risk., Conclusions and Relevance: In this cohort study, risk of MI was best captured by the number of apoB-containing lipoproteins, independent from lipid content (cholesterol or TG) or type of lipoprotein (LDL or TG-rich). This suggests that apoB may be the primary driver of atherosclerosis and that lowering the concentration of all apoB-containing lipoproteins should be the focus of therapeutic strategies.

Lipoprotein(a) [Lp(a)] has risen to the level of an accepted cardiovascular disease risk factor, but final proof of causality awaits a randomized trial of Lp(a) lowering. Inhibiting apolipoprotein(a) production in the hepatocyte with ribonucleic acid therapeutics has emerged as an elegant and effective solution to reduce plasma Lp(a) levels. Phase 2 clinical trials have shown that the antisense oligonucleotide pelacarsen reduced mean Lp(a) levels by 80%, allowing 98% of subjects to reach on-treatment levels of <125 nmol/l (∼50 mg/dl). The phase 3 Lp(a)HORIZON (Assessing the Impact of Lipoprotein(a) Lowering With TQJ230 on Major Cardiovascular Events in Patients With CVD) outcomes trial is currently enrolling approximately 7,680 patients with history of myocardial infarction, ischemic stroke, and symptomatic peripheral arterial disease and controlled low-density lipoprotein cholesterol to pelacarsen versus placebo. The co-primary endpoints are major adverse cardiovascular events in subjects with Lp(a) >70 mg/dl and >90 mg/dl, in which either of the two being positive will lead to a successful trial. Additional ribonucleic acid-targeted therapies to lower Lp(a) are in preclinical and clinical development. The testing of the Lp(a) hypothesis will provide proof whether Lp(a)-mediated risk can be abolished by potent Lp(a) lowering., Competing Interests: Funding Support and Author Disclosures Dr.Tsimikas has received research support from the Fondation Leducq and partial support from National Institutes of Health grants HL136275, HL106579, HL108735, HL136098, HL128550, and HL135737. Dr. Tsimikas is an employee of the University of California-San Diego and of Ionis Pharmaceuticals; is a co-inventor and receives royalties from patents owned by the University of California San Diego on diagnostic and therapeutic applications; and is a co-founder and has an equity interest in Oxitope and its affiliates (“Oxitope”) as well as in Kleanthi Diagnostics (“Kleanthi”) (although these relationships have been identified for conflict-of-interest management based on the overall scope of the project and its potential benefit to Oxitope and Kleanthi, the research findings included in this particular publication may not necessarily relate to the interests of Oxitope and Kleanthi; the terms of this arrangement have been reviewed and approved by the University of California San Diego in accordance with its conflict-of-interest policies). Dr. Moriarty has served as an advisor, consultant, and received research support from Regeneron, Sanofi, Amgen, Esperion, Kaneka, Amarin, Stage II Innovations/Renew, Novartis, Ionis, Akcea, FH Foundation, GB Life Sciences, Aegerion, Gemphire, and Pfizer. Dr. Stroes has received fees paid to his institution from Amgen, Akcea, Athera, Sanofi-Regeneron, Esperion, Novo Nordisk, Lily, and Novartis., (Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Familial hypercholesterolemia is characterised by high low-density lipoprotein-cholesterol levels and is caused by a pathogenic variant in LDLR , APOB or PCSK9 . We investigated which proportion of suspected familial hypercholesterolemia patients was genetically confirmed, and whether this has changed over the past 20 years in The Netherlands., Methods: Targeted next-generation sequencing of 27 genes involved in lipid metabolism was performed in patients with low-density lipoprotein-cholesterol levels greater than 5 mmol/L who were referred to our centre between May 2016 and July 2018. The proportion of patients carrying likely pathogenic or pathogenic variants in LDLR , APOB or PCSK9, or the minor familial hypercholesterolemia genes LDLRAP1, ABCG5, ABCG8, LIPA and APOE were investigated. This was compared with the yield of Sanger sequencing between 1999 and 2016., Results: A total of 227 out of the 1528 referred patients (14.9%) were heterozygous carriers of a pathogenic variant in LDLR (80.2%), APOB (14.5%) or PCSK9 (5.3%). More than 50% of patients with a Dutch Lipid Clinic Network score of 'probable' or 'definite' familial hypercholesterolemia were familial hypercholesterolemia mutation-positive; 4.8% of the familial hypercholesterolemia mutation-negative patients carried a variant in one of the minor familial hypercholesterolemia genes. The mutation detection rate has decreased over the past two decades, especially in younger patients in which it dropped from 45% in 1999 to 30% in 2018., Conclusions: A rare pathogenic variant in LDLR , APOB or PCSK9 was identified in 14.9% of suspected familial hypercholesterolemia patients and this rate has decreased in the past two decades. Stringent use of clinical criteria algorithms is warranted to increase this yield. Variants in the minor familial hypercholesterolemia genes provide a possible explanation for the familial hypercholesterolemia phenotype in a minority of patients.