Human Genetics and the Causal Role of Lipoprotein(a) for Various Diseases

Association between lipoprotein(a), LPA genetic risk score, aortic valve disease, and subsequent major adverse cardiovascular events

AIMS

Cohort studies have demonstrated associations between calcific aortic valve disease (CAVD) and Lp(a). As Lp(a) is almost entirely genetically determined, in this study, we aim to determine whether Lp(a), when predicted from genetic data, is associated with CAVD and major adverse cardiovascular events (MACEs).

METHODS AND RESULTS

Patients undergoing coronary angiography between January 2012 and May 2013 were invited to participate in the study. Of 752 analysable participants, 446 had their Lp(a) measured and 703 had a calculable LPA genetic risk score (GRS). The primary outcomes were the presence of CAVD at baseline and MACE over a 7-year follow-up. The GRS explained 45% of variation in Lp(a). After adjustment for cardiac risk factors and coronary artery disease (CAD), the odds of CAVD increased with increasing Lp(a) [odds ratio (OR) 1.039 per 10-unit increase, 95% confidence interval (CI) 1.022-1.057, P < 0.001] and GRS (OR 1.054 per 10-unit increase, 95% CI 1.024-1.086; P < 0.001). Lipoprotein(a) and the GRS as continuous variables were not associated with subsequent MACEs. A dichotomized GRS (>54) was associated with MACE, but this relationship became non-significant when CAD classification was added into the model (OR 1.333, 95% CI 0.927-1.912; P = 0.12).

CONCLUSION

An LPA GRS can explain 45% of variation in Lp(a) levels, and both Lp(a) and the GRS are associated with CAVD. An elevated GRS is associated with future cardiac events in a secondary risk setting, but, if the CAD status is known, it does not provide additional prognostic information.

Lipoprotein(a) and Lung Function Are Associated in Older Adults: Longitudinal and Cross-Sectional Analyses

While numerous studies have confirmed a causal association between lipoprotein(a) [Lp(a)] and cardiovascular diseases, only a few studies have assessed the relationship between Lp(a) and pulmonary health, with inconsistent findings regarding this topic. This study's aim was to examine whether levels of serum Lp(a) are associated with lung function in a dataset of relatively healthy older adults. We used longitudinal data collected at two time points 7.4 ± 1.5 years apart from 679 participants (52% women, 68 [65-71] years old) from the Berlin Aging Study II (BASE-II). Multiple linear regression models adjusting for covariates were applied to examine the association between Lp(a) and lung function. The forced expiratory volume in one second (FEV1) and the forced vital capacity (FVC) were higher in both men and women with higher Lp(a) levels. However, since this association between lung function parameters and Lp(a) was not supported by Mendelian randomization analyses using recent genome-wide association study data, these relationships should be investigated in future work, as the observed differences are, in part, considerable and potentially clinically relevant.

Lipoprotein (a) and cerebrovascular disease

The role of lipoprotein (a) [Lp(a)] in cerebrovascular disease is a topic of importance. In this narrative review, pertinent studies have been leveraged to comprehensively examine this relationship from diverse perspectives.Lp(a) shares structural traits with low-density lipoprotein cholesterol. Lp(a) is synthesized by hepatocytes, and its plasma levels are genetically determined by the LPA gene, which produces apolipoprotein (a).Numerous epidemiological studies have confirmed the positive correlation between elevated serum Lp(a) levels and the occurrence or recurrence of cerebrovascular events, especially ischemic strokes, in adults. It should be noted that the correlation strength varies among studies and is marginal in Mendelian randomization studies.Regarding pediatric patients, screening is currently limited to those with a relevant medical history. Lp(a) seems to play a significant role in the pathogenesis of arterial ischemic stroke in children because environmental thrombotic and atherogenic factors are generally not present.Phase 3 trials of novel Lp(a) targeting agents, such as pelacarsen and olpasiran, are anticipated to demonstrate their efficacy in reducing the incidence of stroke. Given the richness of the literature, new guidelines regarding Lp(a) screening and management in targeted populations are warranted to provide more effective primary and secondary prevention.

Low Concentration of Lipoprotein(a) is an Independent Predictor of Incident Type 2 Diabetes

The aim of the study was to assess the association between lipoprotein(a) [Lp(a)] concentration and incident type 2 diabetes. A meta-analysis of qualified studies on the relationship of low levels of Lp(a) concentration with incident type 2 diabetes was conducted. PubMed and Cochrane libraries were searched for randomized controlled trials containing data on events. Seven randomized trials with 227178 subjects were included in this analysis. We found an inverse association of the levels of Lp(a) concentration with risk of type 2 diabetes with approximately 37% lower relative risk in the group with the highest concentration compared with group with the lowest concentration. The current available evidence from prospective studies suggests that there is an inverse association between the levels of Lp(a) concentration and risk of type 2 diabetes, with a higher risk of type 2 diabetes at low levels of Lp(a) concentration. Therefore, we believe that the low levels of Lp(a) concentration is an independent predictor of incident type 2 diabetes.

Genetics and Pathophysiological Mechanisms of Lipoprotein(a)-Associated Cardiovascular Risk

Elevated lipoprotein(a) is a genetically transmitted codominant trait that is an independent risk driver for cardiovascular disease. Lipoprotein(a) concentration is heavily influenced by genetic factors, including LPA kringle IV-2 domain size, single-nucleotide polymorphisms, and interleukin-1 genotypes. Apolipoprotein(a) is encoded by the LPA gene and contains 10 subtypes with a variable number of copies of kringle -2, resulting in >40 different apolipoprotein(a) isoform sizes. Genetic loci beyond LPA, such as APOE and APOH, have been shown to impact lipoprotein(a) levels. Lipoprotein(a) concentrations are generally 5% to 10% higher in women than men, and there is up to a 3-fold difference in median lipoprotein(a) concentrations between racial and ethnic populations. Nongenetic factors, including menopause, diet, and renal function, may also impact lipoprotein(a) concentration. Lipoprotein(a) levels are also influenced by inflammation since the LPA promoter contains an interleukin-6 response element; interleukin-6 released during the inflammatory response results in transient increases in plasma lipoprotein(a) levels. Screening can identify elevated lipoprotein(a) levels and facilitate intensive risk factor management. Several investigational, RNA-targeted agents have shown promising lipoprotein(a)-lowering effects in clinical studies, and large-scale lipoprotein(a) testing will be fundamental to identifying eligible patients should these agents become available. Lipoprotein(a) testing requires routine, nonfasting blood draws, making it convenient for patients. Herein, we discuss the genetic determinants of lipoprotein(a) levels, explore the pathophysiological mechanisms underlying the association between lipoprotein(a) and cardiovascular disease, and provide practical guidance for lipoprotein(a) testing.

The Role of Lipoprotein(a) in Peripheral Artery Disease

Lipoprotein(a) is a low-density-lipoprotein-like particle that consists of apolipoprotein(a) bound to apolipoprotein(b). It has emerged as an established causal risk factor for atherosclerotic cardiovascular disease, stroke, and aortic valve stenosis through multifactorial pathogenic mechanisms that include inflammation, atherogenesis, and thrombosis. Despite an estimated 20% of the global population having elevated lipoprotein(a) levels, testing remains underutilized due to poor awareness and a historical lack of effective and safe therapies. Although lipoprotein(a) has a strong association with coronary artery disease and cerebrovascular disease, its relationship with peripheral artery disease is less well established. In this article, we review the epidemiology, biology, and pathogenesis of lipoprotein(a) as it relates to peripheral artery disease. We also discuss emerging treatment options to help mitigate major adverse cardiac and limb events in this population.

High lipoprotein(a): Actionable strategies for risk assessment and mitigation

High levels of lipoprotein(a) [Lp(a)] are causal for atherosclerotic cardiovascular disease (ASCVD). Lp(a) is the most prevalent inherited dyslipidemia and strongest genetic ASCVD risk factor. This risk persists in the presence of at target, guideline-recommended, LDL-C levels and adherence to lifestyle modifications. Epidemiological and genetic evidence supporting its causal role in ASCVD and calcific aortic stenosis continues to accumulate, although various facets regarding Lp(a) biology (genetics, pathophysiology, and expression across race/ethnic groups) are not yet fully understood. The evolving nature of clinical guidelines and consensus statements recommending universal measurements of Lp(a) and the scientific data supporting its role in multiple disease states reinforce the clinical merit to start population screening for Lp(a) now. There is a current gap in the implementation of recommendations for primary and secondary cardiovascular disease (CVD) prevention in those with high Lp(a), in part due to a lack of protocols for management strategies. Importantly, targeted apolipoprotein(a) [apo(a)]-lowering therapies that reduce Lp(a) levels in patients with high Lp(a) are in phase 3 clinical development. This review focuses on the identification and clinical management of patients with high Lp(a). Specifically, we highlight the clinical value of measuring Lp(a) and its use in determining Lp(a)-associated CVD risk by providing actionable guidance, based on scientific knowledge, that can be utilized now to mitigate risk caused by high Lp(a).

Advancements in Omics and Breakthrough Gene Therapies: A Glimpse into the Future of Peripheral Artery Disease

Peripheral artery disease (PAD), a highly prevalent global disease, associates with significant morbidity and mortality in affected patients. Despite progress in endovascular and open revascularization techniques for advanced PAD, these interventions grapple with elevated rates of arterial restenosis and vein graft failure attributed to intimal hyperplasia (IH). Novel multiomics technologies, coupled with sophisticated analyses tools recently powered by advances in artificial intelligence, have enabled the study of atherosclerosis and IH with unprecedented single-cell and spatial precision. Numerous studies have pinpointed gene hubs regulating pivotal atherogenic and atheroprotective signaling pathways as potential therapeutic candidates. Leveraging advancements in viral and nonviral gene therapy (GT) platforms, gene editing technologies, and cutting-edge biomaterial reservoirs for delivery uniquely positions us to develop safe, efficient, and targeted GTs for PAD-related diseases. Gene therapies appear particularly fitting for ex vivo genetic engineering of IH-resistant vein grafts. This manuscript highlights currently available state-of-the-art multiomics approaches, explores promising GT-based candidates, and details GT delivery modalities employed by our laboratory and others to thwart mid-term vein graft failure caused by IH, as well as other PAD-related conditions. The potential clinical translation of these targeted GTs holds the promise to revolutionize PAD treatment, thereby enhancing patients' quality of life and life expectancy.

Targeting Lipoprotein(a): Can RNA Therapeutics Provide the Next Step in the Prevention of Cardiovascular Disease?

Numerous genetic and epidemiologic studies have demonstrated an association between elevated levels of lipoprotein(a) (Lp[a]) and cardiovascular disease. As a result, lowering Lp(a) levels is widely recognized as a promising strategy for reducing the risk of new-onset coronary heart disease, stroke, and heart failure. Lp(a) consists of a low-density lipoprotein-like particle with covalently linked apolipoprotein A (apo[a]) and apolipoprotein B-100, which explains its pro-thrombotic, pro-inflammatory, and pro-atherogenic properties. Lp(a) serum concentrations are genetically determined by the apo(a) isoform, with shorter isoforms having a higher rate of particle synthesis. To date, there are no approved pharmacological therapies that effectively reduce Lp(a) levels. Promising treatment approaches targeting apo(a) expression include RNA-based drugs such as pelacarsen, olpasiran, SLN360, and lepodisiran, which are currently in clinical trials. In this comprehensive review, we provide a detailed overview of RNA-based therapeutic approaches and discuss the recent advances and challenges of RNA therapeutics specifically designed to reduce Lp(a) levels and thus the risk of cardiovascular disease.

Closing the gaps in patient management of dyslipidemia: stepping into cardiovascular precision diagnostics with apolipoprotein profiling

In persons with dyslipidemia, a high residual risk of cardiovascular disease remains despite lipid lowering therapy. Current cardiovascular risk prediction mainly focuses on low-density lipoprotein cholesterol (LDL-c) levels, neglecting other contributing risk factors. Moreover, the efficacy of LDL-c lowering by statins resulting in reduced cardiovascular risk is only partially effective. Secondly, from a metrological viewpoint LDL-c falls short as a reliable measurand. Both direct and calculated LDL-c tests produce inaccurate test results at the low end under aggressive lipid lowering therapy. As LDL-c tests underperform both clinically and metrologically, there is an urging need for molecularly defined biomarkers. Over the years, apolipoproteins have emerged as promising biomarkers in the context of cardiovascular disease as they are the functional workhorses in lipid metabolism. Among these, apolipoprotein B (ApoB), present on all atherogenic lipoprotein particles, has demonstrated to clinically outperform LDL-c. Other apolipoproteins, such as Apo(a) - the characteristic apolipoprotein of the emerging risk factor lipoprotein(a) -, and ApoC-III - an inhibitor of triglyceride-rich lipoprotein clearance -, have attracted attention as well. To support personalized medicine, we need to move to molecularly defined risk markers, like the apolipoproteins. Molecularly defined diagnosis and molecularly targeted therapy require molecularly measured biomarkers. This review provides a summary of the scientific validity and (patho)physiological role of nine serum apolipoproteins, Apo(a), ApoB, ApoC-I, ApoC-II, ApoC-III, ApoE and its phenotypes, ApoA-I, ApoA-II, and ApoA-IV, in lipid metabolism, their association with cardiovascular disease, and their potential as cardiovascular risk markers when measured in a multiplex apolipoprotein panel.

Digital droplet PCR versus quantitative PCR for lipoprotein (a) kringle IV type 2 repeat polymorphism genetic characterization

BACKGROUND

Lipoprotein(a) [Lp(a)] level variability, related to atherothrombotic risk increase, is mainly attributed to LPA gene, encoding apolipoprotein(a), with kringle IV type 2 (KIV2) copy number variation (CNV) acting as the primary genetic determinant. Genetic characterization of Lp(a) is in continuous growth; nevertheless, the peculiar structural characteristics of this variant constitute a significant challenge to the development of effective detection methods. The aim of the study was to compare quantitative real-time PCR (qPCR) and digital droplet PCR (ddPCR) in the evaluation of KIV2 repeat polymorphism.

METHODS

We analysed 100 subjects tested for cardiovascular risk in which Lp(a) plasma levels were assessed.

RESULTS

Correlation analysis between CNV values obtained with the two methods was slightly significant (R = 0.413, p = 0.00002), because of the wider data dispersion in qPCR compared with ddPCR. Internal controls C1, C2 and C3 measurements throughout different experimental sessions revealed the superior stability of ddPCR, which was supported by a reduced intra/inter-assay coefficient of variation determined in this method compared to qPCR. A significant inverse correlation between Lp(a) levels and CNV values was confirmed for both techniques, but it was higher when evaluated by ddPCR than qPCR (R = -0.393, p = 0.000053 vs R = -0.220, p = 0.028, respectively). When dividing subjects into two groups according to 500 mg/L Lp(a) cut-off value, a significantly lower number of KIV2 repeats emerged among subjects with greater Lp(a) levels, with stronger evidence in ddPCR than in qPCR (p = 0.000013 and p = 0.001, respectively).

CONCLUSIONS

Data obtained support a better performance of ddPCR in the evaluation of KIV2 repeat polymorphism.

Elevated lipoprotein(a) increases risk of subsequent major adverse cardiovascular events (MACE) and coronary revascularisation in incident ASCVD patients: A cohort study from the UK Biobank

BACKGROUND AND AIMS

Elevated lipoprotein(a) [Lp(a)] is a genetic driver for atherosclerotic cardiovascular disease (ASCVD). We aimed to provide novel insights into the associated risk of elevated versus normal Lp(a) levels on major adverse cardiovascular events (MACE) in an incident ASCVD cohort.

METHODS

This was an observational cohort study of incident ASCVD patients. MACE counts and incidence rates (IRs) per 100-person-years were reported for patients with normal (<65 nmol/L) and elevated (>150 nmol/L) Lp(a) within the first year after incident ASCVD diagnosis and overall follow-up. Cox proportional hazard models quantified the risk of MACE associated with a 100 nmol/L increase in Lp(a).

RESULTS

The study cohort included 32,537 incident ASCVD patients; 5204 with elevated and 22,257 with normal Lp(a). Of those with elevated Lp(a), 41.2% had a subsequent MACE, versus 35.61% with normal Lp(a). Within the first year of follow-up, the IRs of composite MACE and coronary revascularisation were significantly higher (p < 0.001) in patients with elevated versus normal Lp(a) (IR difference 6.79 and 4.66). This trend was also observed in the overall follow-up (median 4.7 years). Using time to first subsequent MACE, a 100 nmol/L increase in Lp(a) was associated with an 8.0% increased risk of composite MACE, and 18.6% increased risk of coronary revascularisation during the overall follow-up period.

CONCLUSIONS

The association of elevated Lp(a) with increased risk of subsequent MACE and coronary revascularisation highlights a population who may benefit from earlier and more targeted intervention for cardiovascular risk including Lp(a), particularly within the first year after ASCVD diagnosis. Proactive Lp(a) testing as part of routine clinical practice can help identify and better manage these higher-risk individuals.

An LC-MS-based designated comparison method with similar performance to the Lp(a) reference measurement procedure to guide molar Lp(a) standardization

BACKGROUND

The 2022 consensus statement of the European Atherosclerosis Society (EAS) on lipoprotein(a) (Lp(a)) recognizes the role of Lp(a) as a relevant genetically determined risk factor and recommends its measurement at least once in an individual's lifetime. It also strongly urges that Lp(a) test results are expressed as apolipoprotein (a) (apo(a)) amount of substance in molar units and no longer in confounded Lp(a) mass units (mg/dL or mg/L). Therefore, IVD manufacturers should transition to molar units. A prerequisite for this transition is the availability of an Lp(a) Reference Measurement Procedure (RMP) that allows unequivocal molecular detection and quantification of apo(a) in Lp(a). To that end an ISO 17511:2020 compliant LC-MS based and IFCC-endorsed RMP has been established that targets proteotypic peptides of apolipoprotein(a) (apo(a)) in Lp(a). The RMP is laborious and requires highly skilled operators. To guide IVD-manufacturers of immunoassay-based Lp(a) test kits in the transition from mass to molar units, a Designated Comparison Method (DCM) has been developed and evaluated.

METHODS

To assess whether the DCM provides equivalent results compared to the RMP, the procedural designs were compared and the analytical performance of DCM and RMP were first evaluated in a head-to-head comparison. Subsequently, apo(a) was quantified in 153 human clinical serum samples. Both DCM and RMP were calibrated using external native calibrators that produce results traceable to SRM2B. Measurement uncertainty (MU) was checked against predefined allowable MU.

RESULTS

The major difference in the design of the DCM for apo(a) is the use of only one enzymatic digestion step. The analytical performance of the DCM and RMP for apo(a) is highly similar. In a direct method comparison, equivalent results were obtained with a median regression slope 0.997 of and a median bias of - 0.2 nmol/L (- 0.2%); the intermediate imprecision of the test results was within total allowable error (TEa) (CVa of 10.2% at 90 nmol/L).

CONCLUSIONS

The semi-automated, higher throughput, LC-MS-based method for Lp(a) meets the predefined analytical performance specifications and allowable MU and is hence applicable as a higher order Designated Comparison Method, which is ideally suited to guide IVD manufacturers in the transition from Lp(a) mass to molar units.

Genetic study of the causal effect of lipid profiles on insomnia risk: a Mendelian randomization trial

OBJECTIVES

In response to the controversy surrounding observational studies of the association between lipid profiles and the risk of insomnia, the aim of this study was to analyze lipid profiles, including triglycerides (TG), apolipoprotein A-1 (ApoA-1), apolipoprotein B (ApoB) and lipoprotein A (LPA), in a European population to further assess the causal relationship between these lipid types and insomnia.

MATERIALS AND METHODS

This study explores the causal effect of lipid profiles on insomnia based on a genome-wide association study (GWAS)-derived public dataset using two-sample and multivariate Mendelian randomization (MVMR) analysis. The main MR analyses used inverse variance weighting (IVW) odds ratio (OR), and the sensitivity analyses included weighted median (WM) and MR‒Egger.

RESULTS

Both MR and MVMR showed that lowering ApoA-1 and LPA levels had causal effects on the risk of insomnia [MR: per 10 units, ApoA-1: OR: 0.7546, 95% CI: 0.6075-0.9372, P = 0.011; LPA: OR: 0.8392, 95% CI: 0.7202-0.9778, P = 0.025; MVMR: per 10 units, ApoA-1: OR: 0.7600, 95% CI: 0.6362-0.9079, P = 0.002; LPA, OR: 0.903, 95% CI: 0.8283-0.9845, P = 0.021]. There were no causal effects of TG or ApoB on insomnia (all P > 0.05). The MR‒Egger intercept test, funnel plot, and IVW methods all suggested an absence of strong directional pleiotropy, and leave-one-out permutation analysis did not detect any single single-nucleotide polymorphism that had a strong influence on the results.

CONCLUSION

Elevated levels of ApoA-1 and LPA were independently and causally associated with the risk of insomnia, suggesting that elevated ApoA-1 and LPA levels may contribute to a reduced risk of insomnia.

Efficacy of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitor Treatment for Repeated In-stent Restenosis in a Coronary Artery

A 57-year-old woman experienced chest pain. A coronary angiogram revealed middle left anterior descending artery stenosis. Despite receiving adequate anti-hyperlipidemia treatment and undergoing percutaneous coronary intervention (PCI), she experienced angina and required PCI six more times for in-stent restenosis. As she had high lipoprotein (a) [LP-(a)] levels at the seventh PCI procedure, proprotein convertase subtilisin/kexin type 9 inhibitor (PCSK9i) was administered, and a reduction in the LP-(a) and low-density lipoprotein cholesterol (LDL-C) values was observed. She experienced no recurrence of angina for five years with PCSK9i treatment. PCSK9i can reduce not only LDL-C but also LP-(a) levels, resulting in cardiac event risk reduction.

Lipoproteins, Cholesterol, and Atherosclerotic Cardiovascular Disease in East Asians and Europeans

One fifth of the world population live in East Asia comprising Japan, Korea, and China where ischemic heart disease, a major component of atherosclerotic cardiovascular disease (ASCVD), is the second most frequent cause of death. Each of low-density lipoproteins (LDL), remnant lipoproteins, and lipoprotein(a), summarized as non-high-density lipoproteins (non-HDL) or apolipoprotein B (apoB) containing lipoproteins, causes ASCVD. However, a significant proportion of the evidence on lipoproteins and lipoprotein cholesterol with risk of ASCVD came from White people mainly living in Europe and North America and not from people living in East Asia or of East Asian descent. With a unique biological, geohistorical, and social background in this world region, East Asians have distinctive characteristics that might have potential impact on the association of lipoproteins and lipoprotein cholesterol with risk of ASCVD. Considering the movement across national borders in the World, understanding of lipoprotein and lipoprotein cholesterol evidence on ASCVD in East Asia is important for both East Asian and non-East Asian populations wherever they live in the World.In this review, we introduce the biological features of lipoproteins and lipoprotein cholesterol and the evidence for their association with risk of ASCVD in East Asian and European populations. We also provide an overview of guideline recommendations for prevention of ASCVD in these two different world regions. Finally, specific preventive strategies and future perspectives are touched upon.

Developing an SI-traceable Lp(a) reference measurement system: a pilgrimage to selective and accurate apo(a) quantification

In the past decade a remarkable rebirth of serum/plasma lipoprotein(a) (Lp(a)) as an independent risk factor of cardiovascular disease (CVD) occurred. Updated evidence for a causal continuous association in different ethnic groups between Lp(a) concentrations and cardiovascular outcomes has been published in the latest European Atherosclerosis Society (EAS) Lp(a) consensus statement. Interest in measuring Lp(a) at least once in a person's lifetime moreover originates from the development of promising new Lp(a) lowering drugs. Accurate and clinically effective Lp(a) tests are of key importance for the timely detection of high-risk individuals and for future evaluation of the therapeutic effects of Lp(a) lowering medication. To this end, it is necessary to improve the performance and standardization of existing Lp(a) tests, as is also noted in the Lp(a) consensus statement. Consequently, a state-of-the-art internationally endorsed reference measurement system (RMS) must be in place that allows for performance evaluation of Lp(a) field tests in order to certify their validity and accuracy. An ELISA-based RMS from Northwest Lipid Research Laboratory (University of Washington, Seattle, USA) has been available since the 1990s. A next-generation apo(a)/Lp(a) RMS is now being developed by a working group from the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC). The envisioned apo(a) RMS is based on the direct measurement of selected proteotypic fragments generated after proteolytic digestion using quantitative protein mass spectrometry (MS). The choice for an MS-based RMS enables selective measurement of the proteotypic peptides and is by design apo(a) isoform insensitive. Clearly, the equimolar conversion of apo(a) into the surrogate peptide measurands is required to obtain accurate Lp(a) results. The completeness of proteolysis under reaction conditions from the candidate reference measurement procedure (RMP) has been demonstrated for the quantifying apo(a) peptides. Currently, the candidate apo(a) RMP is endorsed by the IFCC and recommendations for suitable secondary reference materials have been made in a recent commutability study paper. Ongoing efforts toward a complete apo(a) RMS that is listed by the Joint Committee on Traceability in Laboratory Medicine (JCTLM) are focused on the peptide-based calibration and the establishment of a network of calibration laboratories running the apo(a) RMS in a harmonized way. Once completed, it will be the holy grail for evaluation and certification of Lp(a) field methods.

Is Lipoprotein(a) Clinically Actionable with Today's Evidence? The Answer is Yes

PURPOSE OF REVIEW

Lipoprotein(a) is an independent risk factor for cardiovascular disease. We review the ongoing shifts in consensus guidelines for the testing and management of Lp(a) and provide insight into whether current evidence suggests that awareness and testing of Lp(a) is clinically actionable.

RECENT FINDINGS

GWAS and Mendelian randomization studies have established causal links between elevated Lp(a) and forms of CVD, including CAD and calcific aortic valve disease. Testing of Lp(a) identifies patients with similar risk to that of heterozygous FH, enhances risk stratification in patients with borderline/intermediate risk as determined through traditional factors, and facilitates the assessment of inherited CVD risk through cascade screening in patients with known family history of elevated Lp(a). Reductions in Lp(a) through non-targeted therapies including PCSK9 inhibition and lipoprotein apheresis have demonstrated reductions in ASCVD risk that are likely attributable to lowering Lp(a). Targeted therapies to potently lower Lp(a) are in clinical development. Lp(a) is actionable, and can be used to identify high risk patients for primary prevention and their family members through cascade screening, and to guide intensification of therapy in primary and secondary prevention of ASCVD.

Lipoprotein(a): Just an Innocent Bystander in Arterial Hypertension?

Elevated plasma lipoprotein(a) [Lp(a)] is a relatively common and highly heritable trait conferring individuals time-dependent risk of developing atherosclerotic cardiovascular disease (CVD). Following its first description, Lp(a) triggered enormous scientific interest in the late 1980s, subsequently dampened in the mid-1990s by controversial findings of some prospective studies. It was only in the last decade that a large body of evidence has provided strong arguments for a causal and independent association between elevated Lp(a) levels and CVD, causing renewed interest in this lipoprotein as an emerging risk factor with a likely contribution to cardiovascular residual risk. Accordingly, the 2022 consensus statement of the European Atherosclerosis Society has suggested inclusion of Lp(a) measurement in global risk estimation. The development of highly effective Lp(a)-lowering drugs (e.g., antisense oligonucleotides and small interfering RNA, both blocking LPA gene expression) which are still under assessment in phase 3 trials, will provide a unique opportunity to reduce "residual cardiovascular risk" in high-risk populations, including patients with arterial hypertension. The current evidence in support of a specific role of Lp(a) in hypertension is somehow controversial and this narrative review aims to overview the general mechanisms relating Lp(a) to blood pressure regulation and hypertension-related cardiovascular and renal damage.

Effects of mixed nut consumption on LDL cholesterol, lipoprotein(a), and other cardiometabolic risk factors in overweight and obese adults

BACKGROUND AND AIMS

Elevated LDL-C, lipoprotein(a) [Lp(a)], and inflammation are associated with greater risk for atherosclerotic cardiovascular events. Consumption of individual nut types decreases these risk factors but knowledge about the effect of mixed nuts on Lp(a) is limited. The objective of this study was to determine the effects of consuming 42.5 g/day of mixed nuts on LDL-C, Lp(a), and inflammatory markers in individuals with overweight or obesity.

METHODS AND RESULTS

In a 16-week randomized control trial, 29 participants with overweight or obesity (BMI 25-40 kg/m²) consumed either 42.5 g/day of mixed nuts (cashews, almonds, macadamia nuts, Brazil nuts, pecans, pistachios, walnuts, and peanuts) or 69 g/day isocaloric pretzels. Blood samples were collected at baseline, week 8, and week 16 for analysis on total cholesterol (TC), LDL-C, Lp(a), inflammation markers, glucose, insulin, adiponectin and liver function enzymes. No significant differences were seen in TC, LDL-C, HDL-C, Lp(a), or liver function enzymes between the two groups. Participants consuming mixed nuts had significantly lower body fat percentage and diastolic blood pressure, and higher adiponectin (all P ≤ 0.05). C-reactive protein (CRP) and 8-oxo-deoxyguanosis (8-oxodG) showed non-significant decreasing trends and total antioxidant capacity (TAC) had a non-significant increasing trend in the mixed nut group.

CONCLUSION

Consumption of mixed nuts had no evidence of an effect on LDL-C or Lp(a) throughout the intervention. Notably, mixed nut consumption lowered body fat percentage without significant changes in body weight or BMI. Future studies with larger sample sizes investigating the changing trends of CRP, 8-oxodG, and TAC are warranted.

CLINICAL TRIAL REGISTER

NCT03375866.

Considerations for routinely testing for high lipoprotein(a)

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.

Lipoprotein(a) and calcific aortic valve disease initiation and progression: a systematic review and meta-analysis

Although evidence indicates the association of lipoprotein(a) [Lp(a)] with atherosclerosis, the link with calcific aortic valve disease (CAVD) is unclear. This systematic review and meta-analysis explores the connection between Lp(a) and aortic valve calcification and stenosis (AVS). We included all relevant studies, indexed in eight databases, up to February 2023. A total of 44 studies (163 139 subjects) were included, with 16 of them being further meta-analysed. Despite considerable heterogeneity, most studies support the relationship between Lp(a) and CAVD, especially in younger populations, with evidence of early aortic valve micro-calcification in elevated-Lp(a) populations. The quantitative synthesis showed higher Lp(a) levels, by 22.63 nmol/L (95% CI: 9.98-35.27), for patients with AVS, while meta-regressing the data revealed smaller Lp(a) differences for older populations with a higher proportion of females. The meta-analysis of eight studies providing genetic data, revealed that the minor alleles of both rs10455872 and rs3798220 LPA gene loci were associated with higher risk for AVS (pooled odds ratio 1.42; 95% CI: 1.34-1.50 and 1.27; 95% CI: 1.09-1.48, respectively). Importantly, high-Lp(a) individuals displayed not only faster AVS progression, by a mean difference of 0.09 m/s/year (95% CI: 0.09-0.09), but also a higher risk of serious adverse outcomes, including death (pooled hazard ratio 1.39; 95% CI: 1.01-1.90). These summary findings highlight the effect of Lp(a) on CAVD initiation, progression and outcomes, and support the early onset of Lp(a)-related subclinical lesions before clinical evidence.

Lipoprotein (a) and myocardial infarction: impact on long-term mortality

BACKGROUND AND AIMS

Lipoprotein (a) [Lp(a)] is a genetically regulated lipoprotein particle that is an independent risk factor for coronary atherosclerotic heart disease. However, the correlation between Lp(a) and left ventricular ejection fraction (LVEF) in patients with myocardial infarction (MI) has been poorly studied. The present study investigated the correlation between Lp(a) and LVEF, as well as the impact of Lp(a) on long-term mortality in patients with MI.

METHODS

Patients who underwent coronary angiography resulting in MI diagnosis between May 2018 and March 2020 at the First Affiliated Hospital of Anhui Medical University were included in this study. The patients were divided into groups based on the Lp(a) concentration and LVEF (reduced ejection fraction group: < 50%; normal ejection fraction group: ≥ 50%). Then, correlations between the Lp(a) level and LVEF, as well as the impact of Lp(a) on mortality, were assessed.

RESULTS

This study included 436 patients with MI. The Lp(a) level and LVEF were significantly and negatively correlated (r = -0.407, β = -0.349, P < 0.001). The area under the receiver operating characteristic curve (ROC) indicated that an Lp(a) concentration > 455 mg/L was the best predictive value for reduced ejection fraction (AUC: 0.7694, P < 0.0001). The clinical endpoints did not differ based on the Lp(a) concentration. However, all-cause mortality and cardiac mortality differed based on LVEF.

CONCLUSIONS

These results suggest that an elevated Lp(a) concentration predicts reduced ejection fraction and that LVEF predicts all-cause mortality and cardiac mortality in patients with MI.

Frequent questions and responses on the 2022 lipoprotein(a) consensus statement of the European Atherosclerosis Society

In 2022, the European Atherosclerosis Society (EAS) published a new consensus statement on lipoprotein(a) [Lp(a)], summarizing current knowledge about its causal association with atherosclerotic cardiovascular disease (ASCVD) and aortic stenosis. One of the novelties of this statement is a new risk calculator showing how Lp(a) influences lifetime risk for ASCVD and that global risk may be underestimated substantially in individuals with high or very high Lp(a) concentration. The statement also provides practical advice on how knowledge about Lp(a) concentration can be used to modulate risk factor management, given that specific and highly effective mRNA-targeted Lp(a)-lowering therapies are still in clinical development. This advice counters the attitude: "Why should I measure Lp(a) if I can't lower it?". Subsequent to publication, questions have arisen relating to how the recommendations of this statement impact everyday clinical practice and ASCVD management. This review addresses 30 of the most frequently asked questions about Lp(a) epidemiology, its contribution to cardiovascular risk, Lp(a) measurement, risk factor management and existing therapeutic options.

Burden of lipoprotein(a) for patients with atherosclerotic cardiovascular disease: A retrospective analysis from the United States

BACKGROUND: Lipoprotein(a) (Lp(a)) is an inherited, independent, and causal risk factor for atherosclerotic cardiovascular disease (ASCVD). OBJECTIVE: To assess the burden of elevated Lp(a) for patients with ASCVD in a real-world setting in the United States. METHODS: This retrospective cohort study assessed US patients with available Lp(a) measurement and established ASCVD using Optum's Clinformatics Data Mart database (2007-2020). Index date was defined as the first diagnosis of an ASCVD event. Patient demographics, medications, health care resource utilization (HCRU), and occurrence of cardiovascular events were assessed for patients with elevated (≥150 nmol/L) vs normal (≥65 nmol/L) Lp(a) levels, within the first year of index date. HCRU was characterized by inpatient hospitalization, inpatient length of stay (LOS), outpatient visits, and emergency department (ED) visits. All comparative analyses of patients with elevated (≥150 nmol/L) vs normal (≥65 nmol/L) Lp(a) levels within the first year of index date were adjusted for age, sex, baseline statin use, and diabetes. RESULTS: 8,372 patients with ASCVD and Lp(a) measurement in nmol/L were included in this study. Patient demographics and baseline clinical characteristics were similar among those with normal and elevated Lp(a). However, the proportion of patients receiving statins and β-blockers at baseline were significantly higher in the elevated vs normal Lp(a) group (54.76% vs 42.91%, P < 0.0001, and 30.92% vs 27.32%, P = 0.0183, respectively). At 1 year of follow-up, the rates per 100 person-years for ASCVD-related inpatient hospitalizations, outpatient hospitalizations, and ED visits were higher among patients with elevated Lp(a) compared with normal Lp(a) (13.33 vs 9.46, 89.08 vs 85.10, and 2.89 vs 2.29, respectively). The mean LOS per ASCVD-related hospitalization was 7.21 days in the elevated and 6.26 days in the normal Lp(a) group (P = 0.3462). During the 1-year post-index follow-up period, 15% of patients in the elevated Lp(a) group required revascularization compared with 10% of patients in the normal Lp(a) group (P = 0.0002). The odds of composite myocardial infarction, ischemic stroke, and revascularization occurrence of events within the first year of index was significantly higher in the elevated Lp(a) group compared with the normal Lp(a) group (1.46; 95% CI = 1.20-1.77; P < 0.05). CONCLUSIONS: HCRU within the first year of ASCVD diagnosis is substantial among patients with ASCVD and elevated Lp(a). Relatively higher rates of inpatient hospitalizations, increased LOS per hospitalization, and requirement of revascularization procedures within the first year of ASCVD index diagnosis were observed in patients with elevated Lp(a) compared with normal Lp(a) levels. Lp(a) testing in routine clinical practice could help in identification of high-risk patients with ASCVD and play an important role in the overall cardiovascular risk management, aiming to reduce the HCRU associated with ASCVD. DISCLOSURES: Ms Fonseca, Dr Laguna, Dr Itani, Dr Rachel Studer, and Dr Ferber are employees of Novartis Pharma AG, Basel, Switzerland. Ms Byrne is an employee of Novartis AG, Dublin, Ireland. Dr Costa-Scharplatz is an employee of Novartis Sweden AB, Stockholm, Sweden. Dr Heo and Ms Dillon are employees of Genesis Research. Genesis Research was commissioned to conduct the study (data extraction and analysis) on behalf of Novartis Pharma AG.

Lipoprotein(a) As a Risk Factor in a Cohort of Hospitalised Cardiovascular Patients: A Retrospective Clinical Routine Data Analysis

INTRODUCTION

Lipoprotein(a) (Lp(a)) is a well-recognised risk factor for ischemic heart disease (IHD) and calcific aortic valve stenosis (AVS).

METHODS

A retrospective observational study of Lp(a) levels (mg/dL) in patients hospitalised for cardiovascular diseases (CVD) in our clinical routine was performed. The Lp(a)-associated risk of hospitalisation for IHD, AVS, and concomitant IHD/AVS versus other non-ischemic CVDs (oCVD group) was assessed by means of logistic regression.

RESULTS

In total of 11,767 adult patients, the association with Lp(a) was strongest in the IHD/AVS group (e^β = 1.010, p < 0.001), followed by the IHD (e^β = 1.008, p < 0.001) and AVS group (e^β = 1.004, p < 0.001). With increasing Lp(a) levels, the risk of IHD hospitalisation was higher compared with oCVD in women across all ages and in men aged ≤75 years. The risk of AVS hospitalisation was higher only in women aged ≤75 years (e^β = 1.010 in age < 60 years, e^β = 1.005 in age 60-75 years, p < 0.05).

CONCLUSIONS

The Lp(a)-associated risk was highest for concomitant IHD/AVS hospitalisations. The differential impact of sex and age was most pronounced in the AVS group with an increased risk only in women aged ≤75 years.

Exploring the role of lipoprotein(a) in cardiovascular diseases and diabetes in Chinese population

A high level of lipoprotein (a) in the plasma has been associated with a variety of cardiovascular diseases and is considered to be an independent predictor of some other diseases. Based on recent studies, the concentration levels of Lp(a) in the Chinese population exhibit a distinctive variation from other populations. In the Chinese population, a high level of Lp(a) indicates a higher incidence of revascularization, platelet aggregation, and thrombogenicity following PCI. Increased risk of atherosclerotic cardiovascular disease (ASCVD) in Chinese population has been linked to higher levels of Lp(a), according to studies. More specifically, it has been found that in Chinese populations, higher levels of Lp(a) were linked to an increased risk of coronary heart disease, severe aortic valve stenosis, deep vein thrombosis in patients with spinal cord injuries, central vein thrombosis in patients receiving hemodialysis, and stroke. Furthermore, new and consistent data retrieved from several clinical trials also suggest that Lp (a) might also play an essential role in some other conditions, including metabolic syndrome, type 2 diabetes and cancers. This review explores the clinical and epidemiological relationships among Lp(a), cardiovascular diseases and diabetes in the Chinese population as well as potential Lp(a) underlying mechanisms in these diseases. However, further research is needed to better understand the role of Lp(a) in cardiovascular diseases and especially diabetes in the Chinese population.

Impact of genetic information on coronary disease risk in Madeira: The GENEMACOR study

INTRODUCTION

Coronary artery disease (CAD), characterized by an atherogenic process in the coronary arteries, is one of the leading causes of death in Madeira. The GENEMACOR (GENEs in MAdeira and CORonary Disease) study sought to investigate the main risk factors - environmental and genetic - and estimate whether a genetic risk score (GRS) improves CAD prediction, discrimination and reclassification.

METHODS

Traditional risk factors and 33 CAD genetic variants were considered in a case-control study with 3139 individuals (1723 patients and 1416 controls). The multivariate analysis assessed the likelihood of CAD. A multiplicative GRS (mGRS) was created, and two models (with and without mGRS) were prepared. Two areas under receiver operating characteristic curve (area under curve (AUC)) were analyzed and compared to discriminate CAD likelihood. Net reclassification improvement (NRI) and integrated discrimination index (IDI) were used to reclassify the population.

RESULTS

All traditional risk factors were strong and independent predictors of CAD, with smoking being the most significant (OR 3.25; p<0.0001). LPA rs3798220 showed a higher CAD likelihood (odds ratio 1.45; p<0.0001). Individuals in the fourth mGRS quartile had an increased CAD probability of 136% (p<0.0001). A traditional risk factor-based model estimated an AUC of 0.73, rising to 0.75 after mGRS inclusion (p<0.0001), revealing a better fit. Continuous NRI better reclassified 28.1% of the population, and categorical NRI mainly improved the reclassification of the intermediate risk group.

CONCLUSIONS

CAD likelihood was influenced by traditional risk factors and genetic variants. Incorporating GRS into the traditional model improved CAD predictive capacity, discrimination and reclassification. These approaches may provide helpful diagnostic and therapeutic advances, especially in the intermediate risk group.

Targeted proteomics using stable isotope labeled protein fragments enables precise and robust determination of total apolipoprotein(a) in human plasma

Lipoprotein(a), also known as Lp(a), is an LDL-like particle composed of apolipoprotein(a) (apo(a)) bound covalently to apolipoprotein B100. Plasma concentrations of Lp(a) are highly heritable and vary widely between individuals. Elevated plasma concentration of Lp(a) is considered as an independent, causal risk factor of cardiovascular disease (CVD). Targeted mass spectrometry (LC-SRM/MS) combined with stable isotope-labeled recombinant proteins provides robust and precise quantification of proteins in the blood, making LC-SRM/MS assays appealing for monitoring plasma proteins for clinical implications. This study presents a novel quantitative approach, based on proteotypic peptides, to determine the absolute concentration of apo(a) from two microliters of plasma and qualified according to guideline requirements for targeted proteomics assays. After optimization, assay parameters such as linearity, lower limits of quantification (LLOQ), intra-assay variability (CV: 4.7%) and inter-assay repeatability (CV: 7.8%) were determined and the LC-SRM/MS results were benchmarked against a commercially available immunoassay. In summary, the measurements of an apo(a) single copy specific peptide and a kringle 4 specific peptide allow for the determination of molar concentration and relative size of apo(a) in individuals.

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.

Association of lipoprotein(a) with all-cause and cause-specific mortality: A prospective cohort study

BACKGROUND

A growing number of studies have demonstrated a causal association between lipoprotein(a) [Lp(a)] and atherosclerotic cardiovascular diseases (ASCVDs), but its association with all-cause and cause-specific mortality remains unclear. Therefore, this study aimed to explore the association of Lp(a) with all-cause and cause-specific mortality.

METHODS

This prospective cohort study included 8,525 participants from the third National Health and Nutrition Examination Survey. Lp(a) was considered an exposure variable, all-cause and cause-specific mortality were used as outcome variables, and all participants were followed from the interview date until death or December 31, 2015. COX proportional hazards regression models, stratified analysis, sensitivity analysis, restricted cubic spline plots and Kaplan-Meier survival curves were used to analyze the association of Lp(a) with all-cause and cause-specific mortality.

RESULTS

After adjusting for traditional cardiovascular risk factors, Lp(a) remained strongly associated with all-cause and CVDs-related mortality (P for trend = 0.007 and < 0.001). Subgroup analyses showed that higher Lp(a) remained associated with higher risk of all-cause mortality in those > 60 years of age, with a BMI < 30 kg/m², and without diabetes, whereas the association between Lp(a) and CVDs-related mortality remained stable in participants ≤ 60 years of age, male, with a BMI < 30 kg/m², with hypertension, without diabetes, or without CVDs (P < 0.05). In sensitivity analyses, we found that the association of Lp(a) with all-cause and CVDs-related mortality remained robust after excluding individuals who died within one year of follow-up (P for trend = 0.041 and 0.002).

CONCLUSIONS

Lp(a) was associated with the risk of all-cause and CVDs-related mortality.

Consensus and guidelines on lipoprotein(a) - seeing the forest through the trees

PURPOSE OF THE REVIEW

Over the past decade, lipoprotein(a) [Lp(a)] made it to several consensus and guideline documents. This review aims to summarize the literature which underlies the various recommendations and compares recent European and North American consensus and guideline documents of the recent 3-4 years.

RECENT FINDINGS

Multiple large epidemiological and genetic studies have provided strong evidence for a causal association between Lp(a) concentrations and atherosclerotic cardiovascular disease (ASCVD) and aortic valve stenosis. There is a dose-dependent linear relationship between Lp(a) and ASCVD risk advocating to consider Lp(a) on a continuous scale rather than using thresholds. The best way to implement this in the clinic is by individualizing the Lp(a)-related risk using tools such as the 'Lp(a) risk calculator' ( http://www.lpaclinicalguidance.com ) that takes into account the Lp(a) level in the context of an individual's traditional risk factors and global risk for ASCVD. There is growing agreement across the guidelines regarding the clinical utility of measuring Lp(a) and more recent expert groups advocate for a general screening approach applied to all adults. As long as the cardiovascular outcomes trials for specific Lp(a)-lowering drugs are in progress, the current management of patients with high Lp(a) should focus on the comprehensive management of all other modifiable ASCVD risk factors which can be therapeutically addressed as per guideline recommendations.

SUMMARY

Since the contribution of high Lp(a) concentrations to global ASCVD risk has been underestimated in the past, a clear recommendation to measure Lp(a) at least once in a person's lifetime is imperative. Recent expert consensus recommendations provide clinicians with direction on how to manage the excess risk associated with elevated Lp(a) concentration by comprehensive and individualized management of modifiable ASCVD risk factors while awaiting the results of clinical trials of Lp(a) targeted therapies.

Lipoprotein(a) predicts recurrent cardiovascular events in patients with prior cardiovascular events post-PCI: five-year findings from a large single center cohort study

Background

It is well established that lipoprotein(a)[Lp(a)] play a vital role in atherosclerosis. Whether Lp(a) can predict recurrence of cardiovascular events (CVEs) in prior CVEs patients is still unclear. We aim to investigate its association with subsequent long-term adverse events in this high-risk population.

Methods

A total of 4,469 patients with prior CVEs history after PCI were consecutively enrolled and categorized according Lp(a) values of < 10 (low), 10 to 30 (medium), and ≥ 30 mg/dL (high). The primary endpoint was MACCE, a composite of all-cause death, myocardial infarction, stroke and unplanned revascularization.

Results

During an average of 5.0 years of follow-up, 1,078 (24.1%) and 206 (4.6%) patients experienced MACCE and all-cause death with 134 (3.0%) of whom from cardiac death. The incidence of MACCE, all-cause death and cardiac death were significantly higher in the high Lp(a) group (p < 0.05). After adjustment of confounding factors, high Lp(a) level remained an independent risk factor for MACCE (adjusted HR 1.240, 95%CI 1.065–1.443, p = 0.006), all-cause death (adjusted HR 1.445, 95%CI 1.023–2.042, p = 0.037) and cardiac death (adjusted HR 1.724, 95%CI 1.108–2.681, p = 0.016). This correlation remained significant when treated as a natural logarithm-transformed continuous variable. This finding is relatively consistent across subgroups and confirmed again in two sensitivity analyses.

Conclusions

Our present study confirmed that Lp(a) was an independent predictor for recurrent CVEs in patients with established CVEs, illustrating that Lp(a) level might be a valuable biomarker for risk stratification and prognostic assessment in this high-risk population.

Lipoprotein(a) levels in children with suspected familial hypercholesterolaemia: a cross-sectional study

AIMS

Familial hypercholesterolaemia (FH) predisposes children to the early initiation of atherosclerosis and is preferably diagnosed by DNA analysis. Yet, in many children with a clinical presentation of FH, no mutation is found. Adult data show that high levels of lipoprotein(a) [Lp(a)] may underlie a clinical presentation of FH, as the cholesterol content of Lp(a) is included in conventional LDL cholesterol measurements. As this is limited to adult data, Lp(a) levels in children with and without (clinical) FH were evaluated.

METHODS AND RESULTS

Children were eligible if they visited the paediatric lipid clinic (1989-2020) and if Lp(a) measurement and DNA analysis were performed. In total, 2721 children (mean age: 10.3 years) were included and divided into four groups: 1931 children with definite FH (mutation detected), 290 unaffected siblings/normolipidaemic controls (mutation excluded), 108 children with probable FH (clinical presentation, mutation not detected), and 392 children with probable non-FH (no clinical presentation, mutation not excluded). In children with probable FH, 32% were found to have high Lp(a) [geometric mean (95% confidence interval) of 15.9 (12.3-20.6) mg/dL] compared with 10 and 10% [geometric means (95% confidence interval) of 11.5 (10.9-12.1) mg/dL and 9.8 (8.4-11.3) mg/dL] in children with definite FH (P = 0.017) and unaffected siblings (P = 0.002), respectively.

CONCLUSION

Lp(a) was significantly higher and more frequently elevated in children with probable FH compared with children with definite FH and unaffected siblings, suggesting that high Lp(a) may underlie the clinical presentation of FH when no FH-causing mutation is found. Performing both DNA analysis and measuring Lp(a) in all children suspected of FH is recommended to assess possible LDL cholesterol overestimation related to increased Lp(a).

Lipoprotein(a) and residual vascular risk in statin-treated patients with first acute ischemic stroke: A prospective cohort study

OBJECTIVES

Statins either barely affect or increase lipoprotein(a) [Lp(a)] levels. This study aimed to explore the factors correlated to the change of Lp(a) levels as well as the relationship between Lp(a) and the recurrent vascular events in statin-treated patients with first acute ischemic stroke (AIS).

METHODS

Patients who were admitted to the hospital with first AIS from October 2018 to September 2020 were eligible for inclusion. Correlation between the change of Lp(a) levels and potential influencing factors was assessed by linear regression analysis. Cox proportional regression models were used to estimate the association between Lp(a) and recurrent vascular events including AIS, transient ischemic attack, myocardial infarction and coronary revascularization.

RESULTS

In total, 303 patients, 69.6% males with mean age 64.26 ± 11.38 years, completed the follow-up. During the follow-up period, Lp(a) levels increased in 50.5% of statin-treated patients and the mean percent change of Lp(a) levels were 14.48% (95% CI 6.35-22.61%). Creatinine (β = 0.152, 95% CI 0.125-0.791, P = 0.007) and aspartate aminotransferase (AST) (β = 0.160, 95% CI 0.175-0.949, P = 0.005) were positively associated with the percent change of Lp(a) levels. During a median follow-up of 26 months, 66 (21.8%) patients had a recurrent vascular event. The median time period between AIS onset and vascular events recurrence was 9.5 months (IQR 2.0-16.3 months). The on-statin Lp(a) level ≥70 mg/dL (HR 2.539, 95% CI 1.076-5.990, P = 0.033) and the change of Lp(a) levels (HR 1.003, 95% CI 1.000-1.005, P = 0.033) were associated with the recurrent vascular events in statin-treated patients with first AIS. Furthermore, the on-statin Lp(a) levels ≥70 mg/dL (HR 3.612, 95% CI 1.018-12.815, P = 0.047) increased the risk of recurrent vascular events in patients with low-density lipoprotein cholesterol (LDL-C) levels < 1.8 mmol/L.

CONCLUSIONS

Lp(a) levels increased in half of statin-treated patients with first AIS. Creatinine and AST were positively associated with the percent change of Lp(a) levels. Lp(a) is a determinant of residual vascular risk and the change of Lp(a) is positively associated with the risk of recurrent vascular events in these patients.

Oxidized phospholipids and lipoprotein-associated phospholipase A2 (Lp-PLA2 ) in atherosclerotic cardiovascular disease: An update

Inflammation and oxidative stress conditions lead to a variety of oxidative modifications of lipoprotein phospholipids implicated in the occurrence and development of atherosclerotic lesions. Lipoprotein-associated phospholipase A2 (Lp-PLA₂ ) is established as an independent risk biomarker of atherosclerosis-related cardiovascular disease (ASCVD) and mediates vascular inflammation through the regulation of lipid metabolism in the blood and in atherosclerotic lesions. Lp-PLA₂ is associated with low- and high-density lipoproteins and Lipoprotein (a) in human plasma and specifically hydrolyzes oxidized phospholipids involved in oxidative stress modification. Several oxidized phospholipids (OxPLs) subspecies can be detoxified through enzymatic degradation by Lp-PLA₂ activation, forming lysophospholipids and oxidized non-esterified fatty acids (OxNEFAs). Lysophospholipids promote the expression of adhesion molecules, stimulate cytokines production (TNF-α, IL-6), and attract macrophages to the arterial intima. The present review article discusses new data on the functional roles of OxPLs and Lp-PLA₂ associated with lipoproteins.

Single-cell transcriptomics reveal cellular diversity of aortic valve and the immunomodulation by PPARγ during hyperlipidemia

Valvular inflammation triggered by hyperlipidemia has been considered as an important initial process of aortic valve disease; however, cellular and molecular evidence remains unclear. Here, we assess the relationship between plasma lipids and valvular inflammation, and identify association of low-density lipoprotein with increased valvular lipid and macrophage accumulation. Single-cell RNA sequencing analysis reveals the cellular heterogeneity of leukocytes, valvular interstitial cells, and valvular endothelial cells, and their phenotypic changes during hyperlipidemia leading to recruitment of monocyte-derived MHC-II^hi macrophages. Interestingly, we find activated PPARγ pathway in Cd36⁺ valvular endothelial cells increased in hyperlipidemic mice, and the conservation of PPARγ activation in non-calcified human aortic valves. While the PPARγ inhibition promotes inflammation, PPARγ activation using pioglitazone reduces valvular inflammation in hyperlipidemic mice. These results show that low-density lipoprotein is the main lipoprotein accumulated in the aortic valve during hyperlipidemia, leading to early-stage aortic valve disease, and PPARγ activation protects the aortic valve against inflammation.

Identifying the mechanisms underlying the early inflammatory phase of aortic valve disease is crucial for disease prevention. Here the authors perform single-cell RNA sequencing to show the immunomodulatory role of PPARγ in valvular endothelial cells during hyperlipidemia.

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.

Elevated lipoprotein(a) as a predictor for coronary events in older men

Elevated circulating lipoprotein (a) [Lp(a)] is associated with an increased risk of first and recurrent cardiovascular events; however, the effect of baseline Lp(a) levels on long-term outcomes in an elderly population is not well understood. The current single-center prospective study evaluated the association of Lp(a) levels with incident acute coronary syndrome to identify populations at risk of future events. Lp(a) concentration was assessed in 755 individuals (mean age of 71.9 years) within the community and followed for up to 8 years (median time to event, 4.5 years; interquartile range, 2.5–6.5 years). Participants with clinically relevant high levels of Lp(a) (>50 mg/dl) had an increased absolute incidence rate of ASC of 2.00 (95% CI, 1.0041) over 8 years (P = 0.04). Moreover, Kaplan-Meier cumulative event analyses demonstrated the risk of ASC increased when compared with patients with low (<30 mg/dl) and elevated (30–50 mg/dl) levels of Lp(a) over 8 years (Gray’s test; P = 0.16). Within analyses adjusted for age and BMI, the hazard ratio was 2.04 (95% CI, 1.0–4.2; P = 0.05) in the high versus low Lp(a) groups. Overall, this study adds support for recent guidelines recommending a one-time measurement of Lp(a) levels in cardiovascular risk assessment to identify subpopulations at risk and underscores the potential utility of this marker even among older individuals at a time when potent Lp(a)-lowering agents are undergoing evaluation for clinical use.

Elevated Lp(a) and course of COVID-19: Is there a relationship?

Background

Lipoprotein (a)–Lp(a) has proinflammatory, prothrombotic and proatherogenic properties and may theoretically influence the course of COVID-19.

Objectives

The aim of the study was to explore whether patients hospitalized due to COVID-19 with Lp(a) ≥30mg/dl may develop a worse course of the disease, increased incidence of thromboembolic complications, intubation and ICU hospitalization or death.

Patients and methods

A retrospective analysis was performed of 124 patients hospitalized due to COVID-19 in the Department of Internal Diseases and Clinical Pharmacology between 29 November 2020 and 15 April 2021. The only exclusion criterion was age≥80 years. Patients were divided into two groups: 1. COVID-19 patients with Lp(a) <30mg/dl regarded as not elevated n = 80; 2. COVID-19 patients with Lp(a) ≥30 regarded as elevated n = 44.

Results

A total of 124 COVID-19 patients were included in the study (66 men and 58 women) with a mean age of 62.8±11 years. COVID-19 patients with elevated Lp(a) level had significantly longer hospitalization time (11 vs. 9.5 days; p = 0.0362), more extensive radiological changes in CT scan (35 vs. 30%; p = 0.0301) and higher oxygen demand on admission (8 vs. 5L/min; p = 0.0428). Elevated Lp(a) was also associated with significantly higher OR for High Flow Nasal Oxygen Therapy (HFNOT) OR = 3.5 95%CI(1.2;8.9), p = 0.0140, Intubation and ICU OR = 4.1 95%CI(1.1;15.2) p = 0.0423, Death OR = 2.8 95%CI(0.9;8.5), p = 0.0409.

Conclusions

Elevated Lp(a) might be one of the factors which contribute to a more severe course of COVID-19; however, further studies including larger groups of patients are needed.

Considerations for routinely testing for high Lp(a)

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.

Lipoprotein(a) measurement issues: Are we making a mountain out of a molehill?

Lipoprotein(a) [Lp(a)] became besides LDL cholesterol one of the most attractive targets for intervention in cardiovascular disease. Strong genetic evidence supports the causal association between high Lp(a) concentrations and cardiovascular outcomes. Since specific Lp(a)-lowering therapies are under clinical investigation, the interest in measuring Lp(a) has markedly increased. However, the special structure of the lead protein component of Lp(a), named apolipoprotein(a), creates difficulties for an accurate measurement of Lp(a). A highly homologous repetitive structure, called kringle IV repeat with up to more the 40 repeats, causes a highly polymorphic protein. Antibodies raised against apolipoprotein(a) are mostly directed against the repetitive structure of this protein, which complicates the measurement of Lp(a) in molar terms. Both measurements in mass (mg/dL) and molar terms (nmol/L) are described and a conversion from one into the another unit is only approximately possible. Working groups for standardization of Lp(a) measurements are going to prepare widely available and improved reference materials, which will be a major step for the measurement of Lp(a). This review discusses many aspects of the difficulties in measuring Lp(a). It tries to distinguish between academic and practical concerns and warns to make a mountain out of a molehill, which does no longer allow to see the patient behind that mountain by simply staring at the laboratory issues. On the other hand, the calibration of some assays raises major concerns, which are anything else but a molehill. This should be kept in mind and we should start measuring Lp(a) with the aim of a better risk stratification for the patient and to identify those patients who might be in urgent need for a specific Lp(a)-lowering therapy as soon as it becomes available.

Familial Hypercholesterolemia and Elevated Lipoprotein(a): Cascade Testing and Other Implications for Contextual Models of Care

Elevated lipoprotein(a) [Lp(a)], a predominantly genetic disorder, is a causal risk factor for atherosclerotic cardiovascular disease (ASCVD) and calcific aortic valvular disease, particularly in patients with familial hypercholesterolemia (FH), a Tier I genomic condition. The combination from birth of the cumulative exposure to elevated plasma concentrations of both Lp(a) and low-density lipoprotein is particularly detrimental and explains the enhanced morbidity and mortality risk observed in patients with both conditions. An excellent opportunity to identify at-risk patients with hyper-Lp(a) at increased risk of ASCVD is to test for hyper-Lp(a) during cascade testing for FH. With probands having FH and hyper-Lp(a), the yield of detection of hyper-Lp(a) is 1 individual for every 2.1-2.4 relatives tested, whereas the yield of detection of both conditions is 1 individual for every 3-3.4 relatives tested. In this article, we discuss the incorporation of assessment of Lp(a) in the cascade testing in FH as a feasible and crucial part of models of care for FH. We also propose a simple management tool to help physicians identify and manage elevated Lp(a) in FH, with implications for the care of Lp(a) beyond FH, noting that the clinical use of RNA therapeutics for specifically targeting the overproduction of Lp(a) in at risk patients is still under investigation.

Clinical investigation of lipoprotein (a) levels in type 2 diabetics for cariovascular diseases prediction and prognosis

OBJECTIVES

We aimed to evaluate the levels of serum lipoprotein a, LP (a), in Jordanian patients with type 2 diabetes mellitus (DM); and to examine its relation to glycemic control, metabolic syndrome (MS) and duration of DM. The LP (a) is considered one of the independent risk factors for coronary artery disease (CAD) in the general population.

METHODS

Fasting blood samples were drawn from 51 diabetic patients with type 2 DM and 31 non-diabetic age and sex control subjects. Serum LP (a) was measured along with other parameters, including triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c) and glycosylated haemoglobin (HbA_1c). Correlation analyses were performed between LP (a) and the various variables measured.

RESULTS

LP (a) measurement showed a skewed distribution towards the lower levels in both groups. Mean LP (a) levels showed a statistically insignificant difference between the two groups. No correlations of LP (a) were observed with age, sex or body mass index (BMI). No correlations of LP (a) with LDL-c, HDL-c, TG, TC, MS, DM duration or HbA_1c were observed. The LP (a) serum levels were significantly higher in type 2 diabetic patients with retinopathy.

CONCLUSIONS

LP (a) serum levels are not increased in type 2 diabetic patients; so, LP (a) may not be a reliable marker for early therapeutic interventions in DM patients, even in high-risk for thrombosis groups.

Segmental duplications and their variation in a complete human genome

Despite their importance in disease and evolution, highly identical segmental duplications (SDs) are among the last regions of the human reference genome (GRCh38) to be fully sequenced. Using a complete telomere-to-telomere human genome (T2T-CHM13), we present a comprehensive view of human SD organization. SDs account for nearly one-third of the additional sequence, increasing the genome-wide estimate from 5.4 to 7.0% [218 million base pairs (Mbp)]. An analysis of 268 human genomes shows that 91% of the previously unresolved T2T-CHM13 SD sequence (68.3 Mbp) better represents human copy number variation. Comparing long-read assemblies from human (n = 12) and nonhuman primate (n = 5) genomes, we systematically reconstruct the evolution and structural haplotype diversity of biomedically relevant and duplicated genes. This analysis reveals patterns of structural heterozygosity and evolutionary differences in SD organization between humans and other primates.

Cis-epistasis at the LPA locus and risk of cardiovascular diseases

AIMS

Coronary artery disease (CAD) has a strong genetic predisposition. However, despite substantial discoveries made by genome-wide association studies (GWAS), a large proportion of heritability awaits identification. Non-additive genetic effects might be responsible for part of the unaccounted genetic variance. Here, we attempted a proof-of-concept study to identify non-additive genetic effects, namely epistatic interactions, associated with CAD.

METHODS AND RESULTS

We tested for epistatic interactions in 10 CAD case-control studies and UK Biobank with focus on 8068 SNPs at 56 loci with known associations with CAD risk. We identified a SNP pair located in cis at the LPA locus, rs1800769 and rs9458001, to be jointly associated with risk for CAD [odds ratio (OR) = 1.37, P = 1.07 × 10-11], peripheral arterial disease (OR = 1.22, P = 2.32 × 10-4), aortic stenosis (OR = 1.47, P = 6.95 × 10-7), hepatic lipoprotein(a) (Lp(a)) transcript levels (beta = 0.39, P = 1.41 × 10-8), and Lp(a) serum levels (beta = 0.58, P = 8.7 × 10-32), while individual SNPs displayed no association. Further exploration of the LPA locus revealed a strong dependency of these associations on a rare variant, rs140570886, that was previously associated with Lp(a) levels. We confirmed increased CAD risk for heterozygous (relative OR = 1.46, P = 9.97 × 10-32) and individuals homozygous for the minor allele (relative OR = 1.77, P = 0.09) of rs140570886. Using forward model selection, we also show that epistatic interactions between rs140570886, rs9458001, and rs1800769 modulate the effects of the rs140570886 risk allele.

CONCLUSIONS

These results demonstrate the feasibility of a large-scale knowledge-based epistasis scan and provide rare evidence of an epistatic interaction in a complex human disease. We were directed to a variant (rs140570886) influencing risk through additive genetic as well as epistatic effects. In summary, this study provides deeper insights into the genetic architecture of a locus important for cardiovascular diseases.