Modern Approaches to Lower Lipoprotein(a) Concentrations and Consequences for Cardiovascular Diseases

Perspectives on the success of plasma lipidomics in cardiovascular drug discovery and future challenges

INTRODUCTION

Plasma lipidomics has emerged as a powerful tool in cardiovascular drug discovery by providing insights into disease mechanisms, identifying potential biomarkers for diagnosis and prognosis, and discovering novel targets for drug development. Widespread application of plasma lipidomics is hampered by technological limitations and standardization and requires a collaborative approach to maximize its use in cardiovascular drug discovery.

AREAS COVERED

This review provides an overview of the utility of plasma lipidomics in cardiovascular drug discovery and discusses the challenges and future perspectives of this rapidly evolving field. The authors discuss the role of lipidomics in understanding the molecular mechanisms of CVD, identifying novel biomarkers for diagnosis and prognosis, and discovering new therapeutic targets for drug development. Furthermore, they highlight the challenges faced in data analysis, standardization, and integration with other omics approaches and propose future directions for the field.

EXPERT OPINION

Plasma lipidomics holds great promise for improving the diagnosis, treatment, and prevention of CVD. While challenges remain in standardization and technology, ongoing research and collaboration among scientists and clinicians will undoubtedly help overcome these obstacles. As lipidomics evolves, its impact on cardiovascular drug discovery and clinical practice is expected to grow, ultimately benefiting patients and healthcare systems worldwide.

Evinacumab for Pediatric Patients With Homozygous Familial Hypercholesterolemia

BACKGROUND

Homozygous familial hypercholesterolemia (HoFH) is a rare genetic disorder characterized by severely elevated low-density lipoprotein cholesterol (LDL-C) levels due to profoundly defective LDL receptor (LDLR) function. Given that severely elevated LDL-C starts in utero, atherosclerosis often presents during childhood or adolescence, creating a largely unmet need for aggressive LDLR-independent lipid-lowering therapies in young patients with HoFH. Here we present the first evaluation of the efficacy and safety of evinacumab, a novel LDLR-independent lipid-lowering therapy, in pediatric patients with HoFH from parts A and B of a 3-part study.

METHODS

The phase 3, part B, open-label study treated 14 patients 5 to 11 years of age with genetically proven HoFH (true homozygotes and compound heterozygotes) with LDL-C >130 mg/dL, despite optimized lipid-lowering therapy (including LDLR-independent apheresis and lomitapide), with intravenous evinacumab 15 mg/kg every 4 weeks.

RESULTS

Evinacumab treatment rapidly and durably (through week 24) decreased LDL-C with profound reduction in the first week, with a mean (SE) LDL-C reduction of -48.3% (10.4%) from baseline to week 24. ApoB (mean [SE], -41.3% [9.0%]), non-high-density lipoprotein cholesterol (-48.9% [9.8%]), and total cholesterol (-49.1% [8.1%]) were similarly decreased. Treatment-emergent adverse events were reported in 10 (71.4%) patients; however, only 2 (14.3%) reported events that were considered to be treatment-related (nausea and abdominal pain). One serious treatment-emergent adverse event of tonsillitis occurred (n=1), but this was not considered treatment-related.

CONCLUSIONS

Evinacumab constitutes a new treatment for pediatric patients with HoFH and inadequately controlled LDL-C despite optimized lipid-lowering therapy, lowering LDL-C levels by nearly half in these extremely high-risk and difficult-to-treat individuals.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04233918.

Exploring PCSK9 Genetic Impact on Lipoprotein(a) via Dual Approaches: Association and Mendelian Randomization

Previous investigations have suggested an association between the PCSK9 common polymorphism E670G and Lipoprotein(a) (Lp(a)) levels, as well as a link between plasma PCSK9 levels and Lp(a) concentrations. However, the causal relationship between plasma PCSK9 and Lp(a) levels remains uncertain. In this study, we explored the association between PCSK9 E670G polymorphism and Lp(a) levels in 614 healthy Taiwanese individuals. Employing a two-sample Mendelian randomization (MR) analysis using openly accessible PCSK9 and Lp(a) summary statistics from the genome-wide association studies (GWAS) and UK Biobank, we aimed to determine if a causal link exists between plasma PCSK9 levels and Lp(a) concentrations. Our findings reveal that the E670G G allele is independently associated with a decreased likelihood of developing elevated Lp(a) levels. This association persists even after adjusting for common cardiovascular risk factors and irrespective of lipid profile variations. The MR analysis, utilizing six PCSK9 GWAS-associated variants as instrumental variables to predict plasma PCSK9 levels, provides compelling evidence of a causal relationship between plasma PCSK9 levels and Lp(a) concentration. In conclusion, our study not only replicates the association between the PCSK9 E670G polymorphism and Lp(a) levels but also confirms a causative relationship between PCSK9 levels and Lp(a) concentrations through MR analysis.

Lipoprotein(a) as a Risk Factor for Cardiovascular Diseases: Pathophysiology and Treatment Perspectives

Cardiovascular disease (CVD) is still a leading cause of morbidity and mortality, despite all the progress achieved as regards to both prevention and treatment. Having high levels of lipoprotein(a) [Lp(a)] is a risk factor for cardiovascular disease that operates independently. It can increase the risk of developing cardiovascular disease even when LDL cholesterol (LDL-C) levels are within the recommended range, which is referred to as residual cardiovascular risk. Lp(a) is an LDL-like particle present in human plasma, in which a large plasminogen-like glycoprotein, apolipoprotein(a) [Apo(a)], is covalently bound to Apo B100 via one disulfide bridge. Apo(a) contains one plasminogen-like kringle V structure, a variable number of plasminogen-like kringle IV structures (types 1-10), and one inactive protease region. There is a large inter-individual variation of plasma concentrations of Lp(a), mainly ascribable to genetic variants in the Lp(a) gene: in the general po-pulation, Lp(a) levels can range from <1 mg/dL to >1000 mg/dL. Concentrations also vary between different ethnicities. Lp(a) has been established as one of the risk factors that play an important role in the development of atherosclerotic plaque. Indeed, high concentrations of Lp(a) have been related to a greater risk of ischemic CVD, aortic valve stenosis, and heart failure. The threshold value has been set at 50 mg/dL, but the risk may increase already at levels above 30 mg/dL. Although there is a well-established and strong link between high Lp(a) levels and coronary as well as cerebrovascular disease, the evidence regarding incident peripheral arterial disease and carotid atherosclerosis is not as conclusive. Because lifestyle changes and standard lipid-lowering treatments, such as statins, niacin, and cholesteryl ester transfer protein inhibitors, are not highly effective in reducing Lp(a) levels, there is increased interest in developing new drugs that can address this issue. PCSK9 inhibitors seem to be capable of reducing Lp(a) levels by 25-30%. Mipomersen decreases Lp(a) levels by 25-40%, but its use is burdened with important side effects. At the current time, the most effective and tolerated treatment for patients with a high Lp(a) plasma level is apheresis, while antisense oligonucleotides, small interfering RNAs, and microRNAs, which reduce Lp(a) levels by targeting RNA molecules and regulating gene expression as well as protein production levels, are the most widely explored and promising perspectives. The aim of this review is to provide an update on the current state of the art with regard to Lp(a) pathophysiological mechanisms, focusing on the most effective strategies for lowering Lp(a), including new emerging alternative therapies. The purpose of this manuscript is to improve the management of hyperlipoproteinemia(a) in order to achieve better control of the residual cardiovascular risk, which remains unacceptably high.

Novel Pharmacological Therapies for the Management of Hyperlipoproteinemia(a)

Lipoprotein(a) [Lp(a)] is a well-established risk factor for cardiovascular disease, predisposing to major cardiovascular events, including coronary heart disease, stroke, aortic valve calcification and abdominal aortic aneurysm. Lp(a) is differentiated from other lipoprotein molecules through apolipoprotein(a), which possesses atherogenic and antithrombolytic properties attributed to its structure. Lp(a) levels are mostly genetically predetermined and influenced by the size of LPA gene variants, with smaller isoforms resulting in a greater synthesis rate of apo(a) and, ultimately, elevated Lp(a) levels. As a result, serum Lp(a) levels may highly vary from extremely low to extremely high. Hyperlipoproteinemia(a) is defined as Lp(a) levels > 30 mg/dL in the US and >50 mg/dL in Europe. Because of its association with CVD, Lp(a) levels should be measured at least once a lifetime in adults. The ultimate goal is to identify individuals with increased risk of CVD and intervene accordingly. Traditional pharmacological interventions like niacin, statins, ezetimibe, aspirin, PCSK-9 inhibitors, mipomersen, estrogens and CETP inhibitors have not yet yielded satisfactory results. The mean Lp(a) reduction, if any, is barely 50% for all agents, with statins increasing Lp(a) levels, whereas a reduction of 80-90% appears to be required to achieve a significant decrease in major cardiovascular events. Novel RNA-interfering agents that specifically target hepatocytes are aimed in this direction. Pelacarsen is an antisense oligonucleotide, while olpasiran, LY3819469 and SLN360 are small interfering RNAs, all conjugated with a N-acetylgalactosamine molecule. Their ultimate objective is to genetically silence LPA, reduce apo(a) production and lower serum Lp(a) levels. Evidence thus so far demonstrates that monthly subcutaneous administration of a single dose yields optimal results with persisting substantial reductions in Lp(a) levels, potentially enhancing CVD risk reduction. The Lp(a) reduction achieved with novel RNA agents may exceed 95%. The results of ongoing and future clinical trials are eagerly anticipated, and it is hoped that guidelines for the tailored management of Lp(a) levels with these novel agents may not be far off.

Significance of traditional herbal medicine for dyslipidemia

Dyslipidemia is a multifactorial disorder that is a causative factor and risk factor for cardiovascular disease. The incidence of dyslipidemia is expected to increase because of the presence of comorbidities. Although several lipid-lowering drugs have been developed and approved, they are not completely effective and are associated with side effects. Traditional herbal medicine (THM) represents an alternative and complementary approach for managing dyslipidemia because of its low toxicity and beneficial effects, such as anti-inflammatory and antioxidant effects. This review focuses on our current understanding of the antidyslipidemic effect of THMs and discusses the associated regulatory mechanisms. The current findings indicate that THM may lead to the development of novel therapeutic regimens for dyslipidemia.

Lipoprotein(a): a Case for Universal Screening in Youth

PURPOSE OF REVIEW

Lipoprotein(a) has emerged as a strong independent risk factor for cardiovascular disease. Targeted screening recommendations for Lp(a) measurement exist for adults and youth known to be at high-risk. However, Lp(a) measurements are not included in universal screening guidelines in the US; hence, most families in the US with high Lp(a) levels who are at risk of future atherosclerotic heart disease, stroke, or aortic stenosis are not recognized. Lp(a) measurement included as part of routine universal lipid screening in youth would identify those children at risk of ASCVD and enable family cascade screening with identification and early intervention for affected family members.

RECENT FINDINGS

Lp(a) levels can be reliably measured in children as young as two years of age. Lp(a) levels are genetically determined. The Lp(a) gene is inherited in a co-dominant fashion. Serum Lp(a) attains adult levels by two years of age and is stable for the lifetime of the individual. Novel therapies that aim to specifically target Lp(a) are in the pipeline, including nucleic acid-based molecules such as antisense oligonucleotides and siRNAs. Inclusion of a single Lp(a) measurement performed as part of routine universal lipid screening in youth (ages 9-11; or at ages 17-21) is feasible and cost effective. Lp(a) screening would identify youth at-risk of ASCVD and enable family cascade screening with identification and early intervention for affected family members.

Current Management and Future Perspectives in the Treatment of Lp(a) with a Focus on the Prevention of Cardiovascular Diseases

Lipoprotein(a) [Lp(a)] is a lipid molecule with atherogenic, inflammatory, thrombotic, and antifibrinolytic effects, whose concentrations are predominantly genetically determined. The association between Lp(a) and cardiovascular diseases (CVDs) has been well-established in numerous studies, and the ability to measure Lp(a) levels is widely available in the community. As such, there has been increasing interest in Lp(a) as a therapeutic target for the prevention of CVD. The impact of the currently available lipid-modifying agents on Lp(a) is modest and heterogeneous, except for the monoclonal antibody proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i), which demonstrated a significant reduction in Lp(a) levels. However, the absolute reduction in Lp(a) to significantly decrease CVD outcomes has not been definitely established, and the magnitude of the effect of PCSK9i seems insufficient to directly reduce the Lp(a)-related CVD risk. Therefore, emerging therapies are being developed that specifically aim to lower Lp(a) levels and the risk of CVD, including RNA interference (RNAi) agents, which have the capacity for temporary and reversible downregulation of gene expression. This review article aims to summarize the effects of Lp(a) on CVD and to evaluate the available evidence on established and emerging therapies targeting Lp(a) levels, focusing on the potential reduction of CVD risk attributable to Lp(a) concentrations.

VLDL receptor gene therapy for reducing atherogenic lipoproteins

Over the past 40 years, there has been considerable research into the management and treatment of atherogenic lipid disorders. Although the majority of treatments and management strategies for cardiovascular disease (CVD) center around targeting low-density lipoprotein cholesterol (LDL-C), there is mounting evidence for the residual CVD risk attributed to high triglyceride (TG) and lipoprotein(a) (Lp(a)) levels despite the presence of lowered LDL-C levels. Among the biological mechanisms for clearing TG-rich lipoproteins, the VLDL receptor (VLDLR) plays a key role in the trafficking and metabolism of lipoprotein particles in multiple tissues, but it is not ordinarily expressed in the liver. Since VLDLR is capable of binding and internalizing apoE-containing TG-rich lipoproteins as well as Lp(a), hepatic VLDLR expression has the potential for promoting clearance of these atherogenic particles from the circulation and managing the residual CVD risk not addressed by current lipid lowering therapies. This review provides an overview of VLDLR function and the potential for developing a genetic medicine based on liver-targeted VLDLR gene expression.

Impact of anti-oestrogen therapy on lipoprotein(a) in postmenopausal women: a systematic review and meta-analysis of double-blind placebo-controlled clinical studies

PURPOSE

The potential mechanisms of endocrine therapy for thrombosis remain currently unclear, and more studies are warranted for further investigation and elucidation. However, high plasma concentration of lipoprotein(a) (Lp(a)) is a recognized prothrombotic factor. The aim of our study was to systematically evaluate the effect of different anti-oestrogen therapy on plasma Lp(a) level in postmenopausal women.

METHODS

A systematic literature search was conducted in multiple electronic databases to identify the randomized, double-blind, placebo-controlled clinical studies on this topic. Effect size for changes in Lp(a) was expressed as mean difference (MD) and 95% confidence intervals (CI).

RESULTS

Data were pooled from 10 clinical trials comprising 24 treatment arms, which included 2049 women (1128 women in the active-treated arms and 921 women in the control arms). Meta-analysis of data suggested that anti-oestrogen therapy in women significantly reduced Lp(a) [MD = -5.92% (95%CI: -9.05%,-2.8%)].

CONCLUSIONS

This observation is of both clinical and pathophysiological relevance, also in view that the identification of molecular determinants and cellular pathways implicated in Lp(a) synthesis and metabolism is still of concern as a critical issue in lipidology and CV prevention.

Lipoprotein (a) in familial hypercholesterolaemia

PURPOSE OF REVIEW

The role of lipoprotein (a) in atherogenesis has been the subject of argument for many years. Evidence that it is raised in familial hypercholesterolaemia has been disputed not least because a mechanism related to low density lipoprotein (LDL) receptor mediated catabolism has been lacking. Whether lipoprotein (a) increases the already raised atherosclerotic cardiovascular disease (ASCVD) risk in familial hypercholesterolaemia is also more dubious than is often stated. We review the evidence in an attempt to provide greater clarity.

RECENT FINDINGS

Lipoprotein (a) levels are raised as a consequence of inheriting familial hypercholesterolaemia. The mechanism for this is likely to involve increased hepatic production, probably mediated by PCSK9 augmented by apolipoprotein E. The extent to which raised lipoprotein (a) contributes to the increased ASCVD risk in familial hypercholesterolaemia remains controversial.Unlike, for example, statins which are effective across the whole spectrum of LDL concentrations, drugs in development to specifically lower lipoprotein (a) are likely to be most effective in people with the highest levels of lipoprotein (a). People with familial hypercholesterolaemia may therefore be in the vanguard of those in whom theses agents should be exhibited.

SUMMARY

Inheritance of familial hypercholesterolaemia undoubtedly increases the likelihood that lipoprotein (a) will be raised. However, in familial hypercholesterolaemia when ASCVD incidence is already greatly increased due to high LDL cholesterol, whether lipoprotein (a) contributes further to this risk cogently needs to be tested with drugs designed to specifically lower lipoprotein (a).

Pre-clinical Toxicological Assessment of A Novel siRNA, SLN360, Targeting Elevated Lipoprotein (a) in Cardiovascular Disease

SLN360 is a liver-targeted N-acetyl galactosamine (GalNAc)-conjugated small interfering RNA (siRNA) with a promising profile for addressing lipoprotein (a)-related cardiovascular risk. Here, we describe the findings from key preclinical safety studies. In vitro, SLN360 specifically reduced LPA expression in primary human hepatocytes with no relevant off-target effects. In rats, 10 mg/kg subcutaneous SLN360 was distributed specifically to the liver and kidney (peak 126 or 246 mg/g tissue at 6 h, respectively), with <1% of peak liver levels observed in all other tested organs. In vitro, no genotoxicity and no effect on human Ether-a-go-go Related Gene currents or proinflammatory cytokine production was observed, whereas in vivo, no SLN360-specific antibodies were detected in rabbit serum. In rat and nonhuman primate 29-day toxicology studies, SLN360 was well tolerated at all doses. In both species, known GalNAc-conjugated siRNA-induced microscopic changes were observed in the kidney and liver, with small increases in alanine aminotransferase and alkaline phosphatase observed in the high dose rats. Findings were in line with previously described siRNA-GalNAc platform-related effects and all observations were reversible and considered nonadverse. In cynomolgus monkeys, liver LPA messenger RNA and serum lipoprotein (a) were significantly reduced at day 30 and after an 8-week recovery period. No dose-related changes in safety assessment endpoints were noted. No SLN360-induced cytokine production, complement activation, or micronucleus formation was observed in vivo. The toxicological profile of SLN360 presented here is restricted to known GalNAc siRNA effects and no other toxicity associated with SLN360 has been noted. The preclinical profile of SLN360 confirmed suitability for entry into clinical studies.

Ten things to know about ten cardiovascular disease risk factors - 2022

The American Society for Preventive Cardiology (ASPC) "Ten things to know about ten cardiovascular disease risk factors - 2022" is a summary document regarding cardiovascular disease (CVD) risk factors. This 2022 update provides summary tables of ten things to know about 10 CVD risk factors and builds upon the foundation of prior annual versions of "Ten things to know about ten cardiovascular disease risk factors" published since 2020. This 2022 version provides the perspective of ASPC members and includes updated sentinel references (i.e., applicable guidelines and select reviews) for each CVD risk factor section. The ten CVD risk factors include unhealthful dietary intake, physical inactivity, dyslipidemia, pre-diabetes/diabetes, high blood pressure, obesity, considerations of select populations (older age, race/ethnicity, and sex differences), thrombosis (with smoking as a potential contributor to thrombosis), kidney dysfunction and genetics/familial hypercholesterolemia. Other CVD risk factors may be relevant, beyond the CVD risk factors discussed here. However, it is the intent of the ASPC "Ten things to know about ten cardiovascular disease risk factors - 2022" to provide a tabular overview of things to know about ten of the most common CVD risk factors applicable to preventive cardiology and provide ready access to applicable guidelines and sentinel reviews.

Value of repeated measurements of lipoprotein (a) to assess cardiovascular risk: a retrospective study

Background: High plasma concentrations of lipoprotein (a) [Lp(a)] are associated with an increased cardiovascular risk. Current guidelines recommend measurement of only a single Lp(a) in an individual's lifetime under specific circumstances to improve cardiovascular risk prediction. Accordingly, the question raised is the number of false positives and negatives missed through only a single measurement.Methods: All Lp(a) measurements between 2004 and March 2021 were retrieved from the laboratory database of the Erasme hospital. Only patients with repeated measurement were included. The first and subsequent Lp(a) measurement were compared. Two different cohorts were studied as a result of a change in Lp(a) determination methodology (n = 2049 and n = 309, respectively). The effects of a third Lp(a) measurement were assessed through binary analyses (n = 678). The 180 mg/dl (430 nmol/L) threshold recommended in the ESC guidelines was assessed first. Analysis was repeated for 100, 70 and 50 mg/dl thresholds of raised Lp(a) levels.Results: A low rate of false negatives (0.8%-1%) and false positives (0.6-0.3%) were revealed with two Lp(a) measurements. There was no difference in regards to the divergent Lp(a) thresholds nor the measurement of Lp(a) on two or three occasions.Conclusion: The present study showed Lp(a) determination to be reproducible. A single measurement is sufficient to assess if a patient exceeds various cut-off values of elevated Lp(a) levels.

The Clinical Importance of Differentiating Monogenic Familial Hypercholesterolemia from Polygenic Hypercholesterolemia

PURPOSE OF REVIEW

The current review discusses the importance and significance of differentiating monogenic familial hypercholesterolemia (FH) from polygenic hypercholesterolemia for clinical purpose.

RECENT FINDINGS

Consistent scientific evidence have demonstrated that, compared to polygenic hypercholesterolemia, monogenic FH patients are at significantly higher risk for premature coronary heart disease (CHD). This is despite both disease entities having a comparable low-density-lipoprotein cholesterol (LDLC) level. Monogenic FH also has poorer therapeutic response compared to its polygenic counterpart. However, there are no current available clinical management guidelines that stratify hypercholesterolemia patients based on genotype. Monogenic FH patients are at higher risk for CHD with poorer therapeutic response. Thus, genotype testing should be performed when available. There is also an urgency to develop genotype-based clinical guideline that stratify patients on genotype and not only based on traditionally known cardiovascular risk factors.