High-density lipoproteins (HDLs) and their main protein, apolipoprotein A-I (apoA-I), are considered immunomodulators of the vascular wall. However, the precise mechanisms are incompletely understood. Using intravital microscopy, flow cytometry, experimental ex vivo models, and bulk RNA sequencing of cultured macrophages, this study reveals the immunomodulatory capacity of apoA-I, which is validated in representative inflammatory models. Intravital imaging in mice shows specific uptake of intravenously injected, lipid-free apoA-I by dermal perivascular macrophages. Supraphysiological doses of apoA-I alter key cellular pathways, involving mammalian target of rapamycin complex 1 (mTORC1) and interferon regulatory factor 8 (IRF8), in THP-1-derived macrophages. In lipopolysaccharide (LPS)-induced skin inflammation, apoA-I pretreatment dampens the inflammatory response and reduces immune cell trafficking in and out of the skin. Moreover, apoA-I inhibits joint inflammation in a mouse model of rheumatoid arthritis (RA). Overall, apoA-I acts as an integrator of vascular-immune interactions by modulating macrophage function in the vicinity of blood vessels. These findings open avenues for HDL-targeting strategies in a broad spectrum of autoimmune disorders, including RA.

Background: Familial chylomicronemia syndrome (FCS) is a rare genetic disorder characterized by severe hypertriglyceridemia causing recurrent acute pancreatitis (AP). Since FCS is a genetic deficiency in functional lipoprotein lipase, conventional triglyceride-lowering therapies are ineffective in this metabolic disorder. Apolipoprotein C-III (apoC-III) inhibitors, including volanesorsen and olezarsen, have emerged as targeted treatments for FCS. Aim: To compare the efficacy and safety of olezarsen 80 mg every four weeks (Q4W) versus volanesorsen 300 mg weekly (QW) in patients with FCS using an anchored matching-adjusted indirect comparison. Materials & methods: Individual patient data from the Balance trial of olezarsen (n = 45) were weighted to match baseline characteristics reported in the APPROACH trial of volanesorsen (n = 66). Outcomes included percent change in fasting triglycerides (TG) and apoC-III at 26 and 52 weeks, and risks of AP events and adverse events at 52 weeks. Results: At 52 weeks, mean differences in fasting TG and apoC-III were -27.4% (95% CI: -69.4, 14.5) and -21.3% (95% CI: -61.9, 19.3). Relative risks of AP, treatment-emergent adverse events, and serious adverse events were 0.23 (95% CI: 0.01, 5.02), 0.87 (95% CI: 0.66, 1.13) and 0.50 (95% CI: 0.08, 3.26) at week 52. The rate ratio for AP events per patient-year was 0.06 (95% CI: 0.003, 1.41). No comparisons were statistically significant. Conclusion: In this matching-adjusted indirect comparison, no statistically significant differences in outcomes were observed between olezarsen and volanesorsen in patients with FCS. These findings provide important comparative context in a setting where head-to-head evidence is unavailable.

BACKGROUND AND AIMS:Homozygous familial hypercholesterolaemia (HoFH) is a rare genetic disorder caused primarily by variants in both alleles of the gene encoding the low-density lipoprotein receptor (LDLR). This subanalysis of the ELIPSE open-label extension (OLE) study assessed the efficacy of evinacumab, an angiopoietin-like 3 inhibitor, by genotype and LDLR function in patients with HoFH. METHODS:Patients aged ≥12 years with HoFH on stable lipid-lowering therapies received evinacumab 15 mg/kg intravenously every 4 weeks. Patients were grouped according to genotype: bi-allelic monogenic identical variants (true homozygous) or bi-allelic monogenic different LDLR variants (compound heterozygous); and by LDLR function: null/null variants resulting in <15% LDLR activity or negative/negative variants predicted to result in <2% LDLR activity. RESULTS:One hundred and sixteen patients enrolled in the OLE. At baseline, 55 (47.4%) had either identical bi-allelic variants in LDLR (n = 53) or LDLRAP1 (n = 2), and 41 (35.3%) had different bi-allelic LDLR variants. Median (Q1, Q3) LDL-C levels were reduced by -53.8% (-42.6%, -67.0%) and -58.1% (-41.5%, -65.9%) by Week 8 of evinacumab treatment in the identical (LDLR or LDLRAP1) and different (LDLR) bi-allelic variant groups, respectively, and remained low at Week 104 (-50.9% [-34.9%, -60.3%] and -47.3% [-34.8%, -67.5%], respectively). At baseline, 36 (31.0%) patients had null/null LDLR variants, and 19 (16.4%) patients had negative/negative LDLR variants. Evinacumab treatment also resulted in rapid and sustained decreases in median LDL-C levels to Week 104 in these subgroups. CONCLUSIONS:Evinacumab treatment resulted in sustained LDL-C reduction in patients with HoFH irrespective of genotype or LDLR function.

AIMS:Both plasma levels of remnant cholesterol and low-density lipoprotein (LDL) cholesterol levels are independent risk factors for atherosclerotic cardiovascular disease. However, only remnant cholesterol has consistently been associated with systemic inflammation. In this study, we aimed to assess the extent to which inflammation mediates the effect of remnant and LDL cholesterol on (non)fatal major adverse cardiovascular events (MACE), comprising of coronary artery disease and ischaemic stroke. METHODS AND RESULTS:This prospective study included 16,445 participants without prior atherosclerotic cardiovascular disease from the EPIC-Norfolk study, with a mean age of 58.8 ± 9.1 years, of which 9,357 (56.9%) were women. Every 1 mmol/L higher remnant cholesterol was associated with 29.5% higher high-sensitivity C-reactive protein (hsCRP) levels [95% Confidence Interval (CI): 22.1, 37.4, P < 0.001], whereas LDL cholesterol was not significantly associated with hsCRP levels in the fully adjusted model. Additionally, each 1 mmol/L higher remnant cholesterol was associated with a hazard ratio (HR) of 1.31 (95% CI: 1.14, 1.50, P < 0.001) for MACE, compared with an HR of 1.21 (95% CI: 1.13, 1.31, P < 0.001) for LDL cholesterol. Mediation analysis showed that hsCRP mediated 5.9% (95% CI: 1.2, 10.6%, P < 0.001) of the effect of remnant cholesterol on MACE, whereas hsCRP did not mediate the effect of LDL cholesterol. CONCLUSION:Plasma remnant cholesterol levels are independently associated with systemic inflammation and cardiovascular events. Inflammation, as measured with hsCRP, contributed minorly to the association between remnant cholesterol and MACE. This underscores the need to address both remnant cholesterol and systemic inflammation separately in the clinical management of cardiovascular disease. LAY SUMMARY:This study finds that systemic inflammation does not influence the effect remnant cholesterol has on cardiovascular disease risk, suggesting the importance of addressing both remnant cholesterol and inflammation to manage cardiovascular health.

BACKGROUND:Hypertriglyceridemia is an established risk factor for cardiovascular disease and acute pancreatitis with postprandial elevations as an important contributor. Olezarsen, an investigational antisense oligonucleotide targeting plasma apolipoprotein C-III (apoC-III), markedly reduces fasting triglyceride levels, though its effect on postprandial triglyceride levels remains to be established. DESIGN:In a double-blind, placebo-controlled trial, 28 patients with fasting triglycerides ≥4 mmol/L received either 2 doses 80mg olezarsen (19 patients) or placebo (9 patients) every 4 weeks.Triglyceride levels were measured in the fasting state and postprandially both at baseline and 7 weeks into treatment. Postprandial triglyceride levels were assessed by calculating the area under the curve (AUC). RESULTS:The mean (±SD) age was 58.6±9.4 years, 82.1% (23) were male and the median [IQR] baseline fasting triglyceride levels were 5.9 [4.5, 9.2] mmol/L. At 7 weeks of olezarsen treatment led to a placebo adjusted triglyceride reduction of 59.3% (-77.3 to -41.2%, p<0.0001). The mean (95% CI) postprandial placebo-adjusted triglyceride AUC was reduced by 50.1% (-68.3 to -31.8%, p<0.0001). Mean (95% CI) incremental AUC (iAUC) was reduced by 30.3% (-56.2 to -4.3%, p=0.026) in the olezarsen versus baseline group; the placebo-adjusted iAUC remained unchanged. The proportion of patients reaching any triglyceride levels ≥10 mmol/L, indicative of increased risk estimation of acute pancreatitis, decreased from 47% to 5% after olezarsen treatment, a 96.6% (p<0.0001) reduction. CONCLUSION:Olezarsen significantly reduces both fasting and postprandial triglyceride levels, these findings highlight olezarsen as a promising intervention to managing hypertriglyceridemia and reducing the risk of hypertriglyceridemia induced acute pancreatitis.

Low-density lipoprotein cholesterol (LDL-C) is the pre-eminent target for the prevention and treatment of atherosclerotic cardiovascular disease (ASCVD). Despite the expansive evidence supporting therapeutic reductions in LDL-C with statin therapy, many high-risk patients do not achieve guideline-recommended treatment targets resulting in avoidable cardiovascular events and higher healthcare expenditures. Underutilization of effective LDL-C lowering is exacerbated by low adherence to statin therapy even among patients following an acute coronary event. Adjunctive therapies such as ezetimibe and PCSK9 monoclonal antibodies remain underutilized, and polypharmacy regimens used for the treatment of cardiovascular disease further increase challenges for patients. Although cardiovascular outcomes data are lacking, inclisiran, a small-interfering RNA (siRNA) targeting PCSK9 mRNA, is available for clinical use. Novel implementation approaches offer the opportunity for more durable or even potentially permanent solutions for lipoprotein-associated cardiovascular disease risk. As an adjunct to statins, these novel approaches may offer more durable approaches for the prevention of ASCVD events. In this review, we discuss the challenges of current LDL-C lowering therapies, achieving LDL-C targets and the necessity of novel approaches.

Inflammation is an important driver of disease in the context of atherosclerosis, and several landmark trials have shown that targeting inflammatory pathways can reduce cardiovascular event rates. However, the high cost and potentially serious adverse effects of anti-inflammatory therapies necessitate more precise patient selection. Traditional biomarkers of inflammation, such as high-sensitivity C-reactive protein, show an association with cardiovascular risk on a population level but do not have specificity for local plaque inflammation. Nowadays, advancements in non-invasive imaging of the vasculature enable direct assessment of vascular inflammation. Positron emission tomography (PET) tracers such as 18F-fluorodeoxyglucose enable detection of metabolic activity of inflammatory cells but are limited by low specificity and myocardial spillover effects. 18F-sodium fluoride is a tracer that identifies active micro-calcification in plaques, indicating vulnerable plaques. Gallium-68 DOTATATE targets pro-inflammatory macrophages by binding to somatostatin receptors, which enhances specificity for plaque inflammation. Coronary computed tomography angiography (CCTA) provides high-resolution images of coronary arteries, identifying high-risk plaque features. Measuring pericoronary adipose tissue attenuation on CCTA represents a novel marker of vascular inflammation. This review examines both established and emerging methods for assessing atherosclerosis-related inflammation, emphasizing the role of advanced imaging in refining risk stratification and guiding personalized therapies. Integrating these imaging modalities with measurements of systemic and molecular biomarkers could shift atherosclerotic cardiovascular disease management towards a more personalized approach.