Phenotypic Characterization of Genetically Lowered Human Lipoprotein(a) Levels

Causal effect of lipoprotein(a) level on chronic kidney disease of European ancestry: a two-sample Mendelian randomization study

INTRODUCTION

Chronic kidney disease is a growing health issue, and the options of prevention and therapy remain limited. Although a number of observational studies have linked higher Lp(a) [lipoprotein(a)] levels to the kidney impairment, the causal relationship remains to be determined. The purpose of this study was to assess the causal association between Lp(a) levels and CKD.

METHODS

We selected eight single-nucleotide polymorphisms (SNPs) significantly associated with Lp(a) levels as instrumental variables. Genome-wide association study (GWAS) from CKDGen consortium yielded the summary data information for CKD. We designed the bidirectional two-sample Mendelian randomization (MR) analyses. The estimates were computed using inverse-variance weighted (IVW), simple median, weighted median, and maximum likelihood. MR-Egger regression was used to detect pleiotropy.

RESULTS

Fixed-effect IVW analysis indicated that genetically predicted Lp(a) levels were associated with CKD significantly (odds ratio, 1.039; 95% CI, 1.009-1.069; p = 0.010). The SNPs showed no pleiotropy according to result of MR-Egger test. Results from sensitivity analyses were consistent. In the inverse MR analysis, random-effect IVW method showed CKD had no causal effect on the elevated Lp(a) (odds ratio, 1.154; 95% CI, 0.845-1.576; p = 0.367).

CONCLUSION

In this bidirectional two-sample MR analysis, the causal deteriorating effects of genetically predicted plasma Lp(a) levels on the risk of CKD were identified. On the contrary, there is no evidence to support a causal effect of CKD on Lp(a) levels.

Bayesian estimation of gene constraint from an evolutionary model with gene features

Measures of selective constraint on genes have been used for many applications, including clinical interpretation of rare coding variants, disease gene discovery and studies of genome evolution. However, widely used metrics are severely underpowered at detecting constraints for the shortest ~25% of genes, potentially causing important pathogenic mutations to be overlooked. Here we developed a framework combining a population genetics model with machine learning on gene features to enable accurate inference of an interpretable constraint metric, shet. Our estimates outperform existing metrics for prioritizing genes important for cell essentiality, human disease and other phenotypes, especially for short genes. Our estimates of selective constraint should have wide utility for characterizing genes relevant to human disease. Finally, our inference framework, GeneBayes, provides a flexible platform that can improve the estimation of many gene-level properties, such as rare variant burden or gene expression differences.

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.

Consensus on lipoprotein(a) of the Spanish Society of Arteriosclerosis. Literature review and recommendations for clinical practice

The irruption of lipoprotein(a) (Lp(a)) in the study of cardiovascular risk factors is perhaps, together with the discovery and use of proprotein convertase subtilisin/kexin type 9 (iPCSK9) inhibitor drugs, the greatest novelty in the field for decades. Lp(a) concentration (especially very high levels) has an undeniable association with certain cardiovascular complications, such as atherosclerotic vascular disease (AVD) and aortic stenosis. However, there are several current limitations to both establishing epidemiological associations and specific pharmacological treatment. Firstly, the measurement of Lp(a) is highly dependent on the test used, mainly because of the characteristics of the molecule. Secondly, Lp(a) concentration is more than 80% genetically determined, so that, unlike other cardiovascular risk factors, it cannot be regulated by lifestyle changes. Finally, although there are many promising clinical trials with specific drugs to reduce Lp(a), currently only iPCSK9 (limited for use because of its cost) significantly reduces Lp(a). However, and in line with other scientific societies, the SEA considers that, with the aim of increasing knowledge about the contribution of Lp(a) to cardiovascular risk, it is relevant to produce a document containing the current status of the subject, recommendations for the control of global cardiovascular risk in people with elevated Lp(a) and recommendations on the therapeutic approach to patients with elevated Lp(a).

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.

Associations between lipoprotein(a), oxidized phospholipids, and extracoronary vascular disease

The roles of lipoprotein(a) [Lp(a)] and related oxidized phospholipids (OxPLs) in the development and progression of coronary disease is known, but their influence on extracoronary vascular disease is not well-established. We sought to evaluate associations between Lp(a), OxPL apolipoprotein B (OxPL-apoB), and apolipoprotein(a) (OxPL-apo(a)) with angiographic extracoronary vascular disease and incident major adverse limb events (MALEs). Four hundred forty-six participants who underwent coronary and/or peripheral angiography were followed up for a median of 3.7 years. Lp(a) and OxPLs were measured before angiography. Elevated Lp(a) was defined as ≥150 nmol/L. Elevated OxPL-apoB and OxPL-apo(a) were defined as greater than or equal to the 75th percentile (OxPL-apoB ≥8.2 nmol/L and OxPL-apo(a) ≥35.8 nmol/L, respectively). Elevated Lp(a) had a stronger association with the presence of extracoronary vascular disease compared to OxPLs and was minimally improved with the addition of OxPLs in multivariable models. Compared to participants with normal Lp(a) and OxPL concentrations, participants with elevated Lp(a) levels were twice as likely to experience a MALE (odds ratio: 2.14, 95% confidence interval: 1.03, 4.44), and the strength of the association as well as the C statistic of 0.82 was largely unchanged with the addition of OxPL-apoB and OxPL-apo(a). Elevated Lp(a) and OxPLs are risk factors for progression and complications of extracoronary vascular disease. However, the addition of OxPLs to Lp(a) does not provide additional information about risk of extracoronary vascular disease. Therefore, Lp(a) alone captures the risk profile of Lp(a), OxPL-apoB, and OxPL-apo(a) in the development and progression of atherosclerotic plaque in peripheral arteries.

Plasminogen missense variants and their involvement in cardiovascular and inflammatory disease

Human plasminogen (PLG), the zymogen of the fibrinolytic protease, plasmin, is a polymorphic protein with two widely distributed codominant alleles, PLG/Asp453 and PLG/Asn453. About 15 other missense or non-synonymous single nucleotide polymorphisms (nsSNPs) of PLG show major, yet different, relative abundances in world populations. Although the existence of these relatively abundant allelic variants is generally acknowledged, they are often overlooked or assumed to be non-pathogenic. In fact, at least half of those major variants are classified as having conflicting pathogenicity, and it is unclear if they contribute to different molecular phenotypes. From those, PLG/K19E and PLG/A601T are examples of two relatively abundant PLG variants that have been associated with PLG deficiencies (PD), but their pathogenic mechanisms are unclear. On the other hand, approximately 50 rare and ultra-rare PLG missense variants have been reported to cause PD as homozygous or compound heterozygous variants, often leading to a debilitating disease known as ligneous conjunctivitis. The true abundance of PD-associated nsSNPs is unknown since they can remain undetected in heterozygous carriers. However, PD variants may also contribute to other diseases. Recently, the ultra-rare autosomal dominant PLG/K311E has been found to be causative of hereditary angioedema (HAE) with normal C1 inhibitor. Two other rare pathogenic PLG missense variants, PLG/R153G and PLG/V709E, appear to affect platelet function and lead to HAE, respectively. Herein, PLG missense variants that are abundant and/or clinically relevant due to association with disease are examined along with their world distribution. Proposed molecular mechanisms are discussed when known or can be reasonably assumed.

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).

Lipoprotein(a), platelet function and cardiovascular disease

Lipoprotein(a) (Lp(a)) is associated with atherothrombosis through several mechanisms, including putative antifibrinolytic properties. However, genetic association studies have not demonstrated an association between high plasma levels of Lp(a) and the risk of venous thromboembolism, and studies in patients with highly elevated Lp(a) levels have shown that Lp(a) lowering does not modify the clotting properties of plasma ex vivo. Lp(a) can interact with several platelet receptors, providing biological plausibility for a pro-aggregatory effect. Observational clinical studies suggest that elevated plasma Lp(a) concentrations are associated with worse long-term outcomes in patients undergoing revascularization. Furthermore, in these patients, those with elevated plasma Lp(a) levels derive more benefit from prolonged dual antiplatelet therapy than those with normal Lp(a) levels. The ASPREE trial in healthy older individuals treated with aspirin showed a reduction in ischaemic events in those who had a single-nucleotide polymorphism in LPA that is associated with elevated Lp(a) levels in plasma, without an increase in bleeding events. In this Review, we re-examine the role of Lp(a) in the regulation of platelet function and suggest areas of research to define further the clinical relevance to cardiovascular disease of the observed associations between Lp(a) and platelet function.

Bayesian estimation of gene constraint from an evolutionary model with gene features

Measures of selective constraint on genes have been used for many applications including clinical interpretation of rare coding variants, disease gene discovery, and studies of genome evolution. However, widely-used metrics are severely underpowered at detecting constraint for the shortest ∼25% of genes, potentially causing important pathogenic mutations to be overlooked. We developed a framework combining a population genetics model with machine learning on gene features to enable accurate inference of an interpretable constraint metric, shet. Our estimates outperform existing metrics for prioritizing genes important for cell essentiality, human disease, and other phenotypes, especially for short genes. Our new estimates of selective constraint should have wide utility for characterizing genes relevant to human disease. Finally, our inference framework, GeneBayes, provides a flexible platform that can improve estimation of many gene-level properties, such as rare variant burden or gene expression differences.

Association between lipoprotein (a) and risk of heart failure: A systematic review and meta-analysis of Mendelian randomization studies

BACKGROUND

Rising incidence of heart failure (HF) in the Western world despite advanced clinical care necessitate exploration of further preventive tools and strategies. Lipoprotein(a) [Lp(a)], recognized as one of the major cardiovascular risk factors has also been implicated as a risk factor for HF. However, existing evidence remains inconclusive and that has led us to perform this meta-analysis.

METHODS

PubMed/Medline, EMBASE and Scopus were systematically searched for studies evaluating an association of Lp(a) with occurrence of HF from inception-till November 2023. Random effects models and I2 statistics were used for pooled odds ratio (OR) and heterogeneity assessment. We performed leave one out sensitivity analyses by sequentially removing one study at a time and recalculating the pooled effect size.

RESULT

Our search rendered in total 360 studies and after final screening this resulted in 7 Mendelian randomization (MR) design. According to the MR analysis, increasing Lp(a) level were significantly associated with increased risk of HF (OR 1.064, 95 % CI: 1.043-1.086, I2= 97.59 %, P < 0.001). In addition, Leave-one-out sensitivity analysis showed that the effect size did not change substantially by removal of any particular study in MR studies and ORs ranged from 1.051 (when excluding Levin) to a maximum of 1.111 (when excluding Wang or Jiang), hereby confirming the association.

CONCLUSION

We were able to show that by meta-analysis of MR data, increasing lipoprotein (a) levels are associated with an increased risk of HF. Whether this is due to a direct effect on heart muscle contraction or whether this is due to an increased risk of ischemic cardiac disease remains to be elucidated.

Oxidized phospholipids in cardiovascular disease

Prolonged or excessive exposure to oxidized phospholipids (OxPLs) generates chronic inflammation. OxPLs are present in atherosclerotic lesions and can be detected in plasma on apolipoprotein B (apoB)-containing lipoproteins. When initially conceptualized, OxPL-apoB measurement in plasma was expected to reflect the concentration of minimally oxidized LDL, but, surprisingly, it correlated more strongly with plasma lipoprotein(a) (Lp(a)) levels. Indeed, experimental and clinical studies show that Lp(a) particles carry the largest fraction of OxPLs among apoB-containing lipoproteins. Plasma OxPL-apoB levels provide diagnostic information on the presence and extent of atherosclerosis and improve the prognostication of peripheral artery disease and first and recurrent myocardial infarction and stroke. The addition of OxPL-apoB measurements to traditional cardiovascular risk factors improves risk reclassification, particularly in patients in intermediate risk categories, for whom improving decision-making is most impactful. Moreover, plasma OxPL-apoB levels predict cardiovascular events with similar or greater accuracy than plasma Lp(a) levels, probably because this measurement reflects both the genetics of elevated Lp(a) levels and the generalized or localized oxidation that modifies apoB-containing lipoproteins and leads to inflammation. Plasma OxPL-apoB levels are reduced by Lp(a)-lowering therapy with antisense oligonucleotides and by lipoprotein apheresis, niacin therapy and bariatric surgery. In this Review, we discuss the role of role OxPLs in the pathophysiology of atherosclerosis and Lp(a) atherogenicity, and the use of OxPL-apoB measurement for improving prognosis, risk reclassification and therapeutic interventions.

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.

Lipoprotein(a): A Review of Risk Factors, Measurements, and Novel Treatment Modalities

The study of lipoprotein(a) [Lp(a)] has long been a source of interest as a possible independent risk factor for atherosclerotic cardiovascular disease (ASCVD). The results of large sample observational studies, genome-wide association studies, and Mendelian randomization studies have been strong indicators supporting the link between ASCVD and Lp(a) despite early studies, with less sensitive assays, failing to show a connection. The recommendations for the indications and frequency of testing Lp(a) levels vary between US, Canadian, and European organizations due to the uncertain role of Lp(a) in ASCVD. The innovation of recent therapies, such as antisense oligonucleotides and small interfering RNA, designed to specifically target and reduce Lp(a) levels by targeting mRNA translation have once more thrust LP(a) into the spotlight of inquiry. These emerging modalities serve the dual purpose of definitively elucidating the connection between elevated Lp(a) levels and atherosclerotic cardiovascular risk, as well as the possibility of providing clinicians with the tools necessary to manage elevated Lp(a) levels in vulnerable populations. This review seeks to examine the mechanisms of atherogenicity of Lp(a) and explore the most current pharmacologic therapies currently in development.

Recommendations of the Experts of the Polish Cardiac Society (PCS) and the Polish Lipid Association (PoLA) on the diagnosis and management of elevated lipoprotein(a) levels

Lipoprotein(a) [Lp(a)] is made up of a low-density lipoprotein (LDL) particle and a specific apolipoprotein(a). The blood concentration of Lp(a) is approximately 90% genetically determined, and the main genetic factor determining Lp(a) levels is the size of the apo(a) isoform, which is determined by the number of KIV2 domain repeats. The size of the apo(a) isoform is inversely proportional to the blood concentration of Lp(a). Lp(a) is a strong and independent cardiovascular risk factor. Elevated Lp(a) levels ≥ 50 mg/dl (≥ 125 nmol/l) are estimated to occur in more than 1.5 billion people worldwide. However, determination of Lp(a) levels is performed far too rarely, including Poland, where, in fact, it is only since the 2021 guidelines of the Polish Lipid Association (PoLA) and five other scientific societies that Lp(a) measurements have begun to be performed. Determination of Lp(a) concentrations is not easy due to, among other things, the different sizes of the apo(a) isoforms; however, the currently available certified tests make it possible to distinguish between people with low and high cardiovascular risk with a high degree of precision. In 2022, the first guidelines for the management of patients with elevated lipoprotein(a) levels were published by the European Atherosclerosis Society (EAS) and the American Heart Association (AHA). The first Polish guidelines are the result of the work of experts from the two scientific societies and their aim is to provide clear, practical recommendations for the determination and management of elevated Lp(a) levels.

Lipoprotein(a) and calcific aortic valve disease: current evidence and future directions

PURPOSE OF REVIEW

Calcific aortic valve disease (CAVD), the most common cause of aortic stenosis (AS), is characterized by slowly progressive fibrocalcific remodelling of the valve cusps. Once symptomatic, severe AS is associated with poor survival unless surgical or transcatheter valve replacement is performed. Unfortunately, no pharmacological interventions have been demonstrated to alter the natural history of CAVD. Lipoprotein(a) [Lp(a)], a low-density lipoprotein-like particle, has been implicated in the pathophysiology of CAVD.

RECENT FINDINGS

The mechanisms by which Lp(a) results in CAVD are not well understood. However, the oxidized phospholipids carried by Lp(a) are considered a crucial mediator of the disease process. An increasing number of studies demonstrate a causal association between plasma Lp(a) levels and frequency of AS and need for aortic valve replacement, which is independent of inflammation, as measured by plasma C-reactive protein levels. However, not all studies show an association between Lp(a) and increased progression of calcification in individuals with established CAVD.

SUMMARY

Epidemiologic, genetic, and Mendelian randomization studies have collectively suggested that Lp(a) is a causal risk factor for CAVD. Whether Lp(a)-lowering can prevent initiation or slow progression of CAVD remains to be demonstrated.

Association of Renal Function and Statin Therapy with Lipoprotein(a) in Patients with Type 2 Diabetes

AIM

A high level of serum lipoprotein(a) [Lp(a)] is associated with kidney disease development in patients with type 2 diabetes (T2DM). Recent studies have suggested that statins may affect serum levels of Lp(a). However, the statin effect is not well-defined in patients with T2DM with kidney dysfunction. This retrospective study aimed to investigate the relevance of kidney dysfunction and statin therapy to Lp(a) in patients with T2DM.

METHODS

Japanese patients with T2DM (n=149, 96 men and 53 women) were divided into two groups: statin users (n=79) and non-statin users (n=70). Multiple logistic regression analyses were performed with Lp(a) as the objective variable and estimated glomerular filtration rate (eGFR), hemoglobin A1c, age, gender, and body mass index as the explanatory variables.

RESULTS

Lp(a) serum levels were higher in statin users than in non-statin users (P=0.022). Multivariate regression analysis results showed an inverse correlation of eGFR to log Lp(a) in all patients (P=0.009) and in non-statin users (P=0.025), but not in statin users. In a multiple logistic regression analysis for median Lp(a), there was an inverse association between eGFR and Lp(a) level (odds ratio, 0.965; 95% confidence interval, 0.935-0.997; P=0.030) in non-statin users as well as in all participants, but not in statin users.

CONCLUSIONS

The present study suggests that a high Lp(a) level in patients with T2DM, except in statin users, is significantly associated with decreased eGFR, indicating that the increased Lp(a) levels under statin therapy might diminish the relationship between Lp(a) and eGFR.

Mendelian Randomization as a Tool for Cardiovascular Research: A Review

Importance

Mendelian randomization (MR) is a statistical approach that has become increasingly popular in the field of cardiovascular disease research. It offers a way to infer potentially causal relationships between risk factors and outcomes using observational data, which is particularly important in cases where randomized clinical trials are not feasible or ethical. With the growing availability of large genetic data sets, MR has become a powerful and accessible tool for studying the risk factors for cardiovascular disease.

Observations

MR uses genetic variation associated with modifiable exposures or risk factors to mitigate biases that affect traditional observational study designs. The approach uses genetic variants that are randomly assigned at conception as proxies for exposure to a risk factor, mimicking a randomized clinical trial. By comparing the outcomes of individuals with different genetic variants, researchers may draw causal inferences about the effects of specific risk factors on cardiovascular disease, provided assumptions are met that address (1) the association between each genetic variant and risk factor and (2) the association of the genetic variants with confounders and (3) that the association between each genetic variant and the outcome only occurs through the risk factor. Like other observational designs, MR has limitations, which include weak instruments that are not strongly associated with the exposure of interest, linkage disequilibrium where genetic instruments influence the outcome via correlated rather than direct effects, overestimated genetic associations, and selection and survival biases. In addition, many genetic databases and MR studies primarily include populations genetically similar to European reference populations; improved diversity of participants in these databases and studies is critically needed.

Conclusions and Relevance

This review provides an overview of MR methodology, including assumptions, strengths, and limitations. Several important applications of MR in cardiovascular disease research are highlighted, including the identification of drug targets, evaluation of potential cardiovascular risk factors, as well as emerging methodology. Overall, while MR alone can never prove a causal relationship beyond reasonable doubt, MR offers a rigorous approach for investigating possible causal relationships in observational data and has the potential to transform our understanding of the etiology and treatment of cardiovascular disease.

Mendelian randomization for cardiovascular diseases: principles and applications

Large-scale genome-wide association studies conducted over the last decade have uncovered numerous genetic variants associated with cardiometabolic traits and risk factors. These discoveries have enabled the Mendelian randomization (MR) design, which uses genetic variation as a natural experiment to improve causal inferences from observational data. By analogy with the random assignment of treatment in randomized controlled trials, the random segregation of genetic alleles when DNA is transmitted from parents to offspring at gamete formation is expected to reduce confounding in genetic associations. Mendelian randomization analyses make a set of assumptions that must hold for valid results. Provided that the assumptions are well justified for the genetic variants that are employed as instrumental variables, MR studies can inform on whether a putative risk factor likely has a causal effect on the disease or not. Mendelian randomization has been increasingly applied over recent years to predict the efficacy and safety of existing and novel drugs targeting cardiovascular risk factors and to explore the repurposing potential of available drugs. This review article describes the principles of the MR design and some applications in cardiovascular epidemiology.

Association between serum lipoprotein(a) and mildly reduced eGFR: a cross-sectional study

Lipoprotein(a) [Lp(a)] is a risk factor for cardiovascular disease (CVD) and aortic stenosis. However, the data on the relationship between Lp(a) and mildly reduced estimated glomerular filtration rate (eGFR) has been disputed. This study was conducted to assess the relationship between Lp(a) concentrations and mildly reduced eGFR in healthy subjects.This community-based, cross-sectional study enrolled 1,064 volunteers aged ≥ 40 years who lived in Yonghong Community, Zhonglou District, Changzhou, China, between December 2016 and December 2017. A mildly reduced eGFR was defined as eGFR between 60 and 90 mL/min/1.73m2. A standardized questionnaire and biochemical measurements were used to gather information about participants. The serum concentration of Lp(a) was determined using the latex-enhanced immunoturbidimetric test. Of the total study population, 34.8% (n = 370) were men, and the mean age was 66.8 ± 8.5 years. A significant association existed between Lp(a) levels and the risk of mildly reduced eGFR. Individuals with the highest tertile of Lp(a) had higher odds of mildly reduced eGFR after adjusting for various confounders (adjusted odds ratio [OR]: 1.80, 95% confidence interval [CI]: 1.24-2.60, P = 0.0025) compared to those with the lowest tertile of Lp(a). Multivariable logistic regression of studies in which Lp(a) was presented as continuous variables showed consistent results (adjusted OR: 1.23 for 1-SD increment of Ln-Lp(a), 95% CI: 1.05-1.43). Subgroup analyses showed that study characteristics such as age, sex, obesity, diabetes, and hypertension status did not significantly affect the association (P for all interactions > 0.05). These results suggest that higher serum Lp(a) level was an independent risk factor for mildly reduced eGFR.

Predictive value of lipoprotein(a) in coronary artery calcification among asymptomatic cardiovascular disease subjects: A systematic review and meta-analysis

AIMS

Studies have indicated inconsistent results regarding the association between plasma levels of Lipoprotein(a) [Lp(a)] and coronary artery calcification (CAC). We performed a systematic review and meta-analysis to investigate the association between elevated levels of Lp(a) and risk of CAC in populations free of cardiovascular disease (CVD) symptoms.

DATA SYNTHESIS

PubMed, Web of Science, Embase, and Scopus were searched up to July 2022 and the methodological quality was assessed using Newcastle-Ottawa Scale (NOS) scale. Random-effects meta-analysis was used to estimate pooled odds ratio (OR) and 95% confidence interval. Out of 298 studies, data from 8 cross-sectional (n = 18,668) and 4 cohort (n = 15,355) studies were used in meta-analysis. Cohort studies demonstrated a positive significant association between Lp(a) and CAC, so that individuals with Lp(a)≥30-50 exposed to about 60% risk of CAC incidence compared to those with lower Lp(a) concentrations in asymptomatic CVD subjects (OR, 1.58; 95% CI, 1.38-1.80; l2, 0.0%; P, 0.483); Subgroup analysis showed that a cut-off level for Lp(a) measurement could not statistically affect the association, but race significantly affected the relationship between Lp(a) and CAC (OR,1.60; 95% CI, 1.41-1.81). Analyses also revealed that both men and women with higher Lp(a) concentrations are at the same risk for increased CAC.

CONCLUSIONS

Blood Lp(a) level was significantly associated with CAC incidence in asymptomatic populations with CVD, indicating that measuring Lp(a) may be a useful biomarker for diagnosing subclinical atherosclerosis in individuals at higher risk of CAC score.

PROSPERO REGISTRATION NUMBER

CRD42022350297.

Consensus document on Lipoprotein(a) from the Italian Society for the Study of Atherosclerosis (SISA)

AIMS

In view of the consolidating evidence on the causal role of Lp(a) in cardiovascular disease, the Italian Society for the Study of Atherosclerosis (SISA) has assembled a consensus on Lp(a) genetics and epidemiology, together with recommendations for its measurement and current and emerging therapeutic approaches to reduce its plasma levels. Data on the Italian population are also provided.

DATA SYNTHESIS

Lp(a) is constituted by one apo(a) molecule and a lipoprotein closely resembling to a low-density lipoprotein (LDL). Its similarity with an LDL, together with its ability to carry oxidized phospholipids are considered the two main features making Lp(a) harmful for cardiovascular health. Plasma Lp(a) concentrations vary over about 1000 folds in humans and are genetically determined, thus they are quite stable in any individual. Mendelian Randomization studies have suggested a causal role of Lp(a) in atherosclerotic cardiovascular disease (ASCVD) and aortic valve stenosis and observational studies indicate a linear direct correlation between cardiovascular disease and Lp(a) plasma levels. Lp(a) measurement is strongly recommended once in a patient's lifetime, particularly in FH subjects, but also as part of the initial lipid screening to assess cardiovascular risk. The apo(a) size polymorphism represents a challenge for Lp(a) measurement in plasma, but new strategies are overcoming these difficulties. A reduction of Lp(a) levels can be currently attained only by plasma apheresis and, moderately, with PCSK9 inhibitor treatment.

CONCLUSIONS

Awaiting the approval of selective Lp(a)-lowering drugs, an intensive management of the other risk factors for individuals with elevated Lp(a) levels is strongly recommended.

Established and Emerging Lipid-Lowering Drugs for Primary and Secondary Cardiovascular Prevention

Despite treatment with statins, patients with elevated low-density lipoprotein cholesterol (LDL-C) and triglycerides remain at increased risk for adverse cardiovascular events. Consequently, novel pharmaceutical drugs have been developed to control and modify the composition of blood lipids to ultimately prevent fatal cardiovascular events in patients with dyslipidaemia. This article reviews established and emerging lipid-lowering drugs regarding their mechanism of action, development stage, ongoing clinical trials, side effects, effect on blood lipids and reduction in cardiovascular morbidity and mortality. We conducted a keyword search to identify studies on established and emerging lipid modifying drugs. Results were summarized in a narrative overview. Established pharmaceutical treatment options include the Niemann-Pick-C1 like-1 protein (NPC1L1) inhibitor ezetimibe, the protein convertase subtilisin-kexin type 9 (PCSK9) inhibitors alirocumab and evolocumab, fibrates as peroxisome proliferator receptor alpha (PPAR-α) activators, and the omega-3 fatty acid icosapent ethyl. Statins are recommended as the first-line therapy for primary and secondary cardiovascular prevention in patients with hypercholesterinaemia and hypertriglyceridemia. For secondary prevention in hypercholesterinaemia, second-line options such as statin add-on or statin-intolerant treatments are ezetimibe, alirocumab and evolocumab. For secondary prevention in hypertriglyceridemia, second-line options such as statin add-on or statin-intolerant treatments are icosapent ethyl and fenofibrate. Robust data for these add-on therapeutics in primary cardiovascular prevention remains scarce. Recent biotechnological advances have led to the development of innovative small molecules (bempedoic acid, lomitapide, pemafibrate, docosapentaenoic and eicosapentaenoic acid), antibodies (evinacumab), antisense oligonucleotides (mipomersen, volanesorsen, pelcarsen, olezarsen), small interfering RNA (inclisiran, olpasiran), and gene therapies for patients with dyslipidemia. These molecules specifically target new cellular pathways, such as the adenosine triphosphate-citrate lyase (bempedoic acid), PCSK9 (inclisiran), angiopoietin-like 3 (ANGPTL3: evinacumab), microsomal triglyceride transfer protein (MTP: lomitapide), apolipoprotein B-100 (ApoB-100: mipomersen), apolipoprotein C-III (ApoC-III: volanesorsen, olezarsen), and lipoprotein (a) (Lp(a): pelcarsen, olpasiran). The authors are hopeful that the development of new treatment modalities alongside new therapeutic targets will further reduce patients' risk of adverse cardiovascular events. Apart from statins, data on new drugs' use in primary cardiovascular prevention remain scarce. For their swift adoption into clinical routine, these treatments must demonstrate safety and efficacy as well as cost-effectiveness in randomized cardiovascular outcome trials.

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.

Daring to dream: Targeting lipoprotein(a) as a causal and risk-enhancing factor

Lipoprotein(a) [Lp(a)], a distinct lipoprotein class, has become a major focus for cardiovascular research. This review is written in light of the recent guideline and consensus statements on Lp(a) and focuses on 1) the causal association between Lp(a) and cardiovascular outcomes, 2) the potential mechanisms by which elevated Lp(a) contributes to cardiovascular diseases, 3) the metabolic insights on the production and clearance of Lp(a) and 4) the current and future therapeutic approaches to lower Lp(a) concentrations. The concentrations of Lp(a) are under strict genetic control. There exists a continuous relationship between the Lp(a) concentrations and risk for various endpoints of atherosclerotic cardiovascular disease (ASCVD). One in five people in the Caucasian population is considered to have increased Lp(a) concentrations; the prevalence of elevated Lp(a) is even higher in black populations. This makes Lp(a) a cardiovascular risk factor of major public health relevance. Besides the association between Lp(a) and myocardial infarction, the relationship with aortic valve stenosis has become a major focus of research during the last decade. Genetic studies provided strong support for a causal association between Lp(a) and cardiovascular outcomes: carriers of genetic variants associated with lifelong increased Lp(a) concentration are significantly more frequent in patients with ASCVD. This has triggered the development of drugs that can specifically lower Lp(a) concentrations: mRNA-targeting therapies such as anti-sense oligonucleotide (ASO) therapies and short interfering RNA (siRNA) therapies have opened new avenues to lower Lp(a) concentrations more than 95%. Ongoing Phase II and III clinical trials of these compounds are discussed in this review.

Plasma tissue-type plasminogen activator is associated with lipoprotein(a) and clinical outcomes in hospitalized patients with COVID-19

Background

Patients with COVID-19 have a higher risk of thrombosis and thromboembolism, but the underlying mechanism(s) remain to be fully elucidated. In patients with COVID-19, high lipoprotein(a) (Lp(a)) is positively associated with the risk of ischemic heart disease. Lp(a), composed of an apoB-containing particle and apolipoprotein(a) (apo(a)), inhibits the key fibrinolytic enzyme, tissue-type plasminogen activator (tPA). However, whether the higher Lp(a) associates with lower tPA activity, the longitudinal changes of these parameters in hospitalized patients with COVID-19, and their correlation with clinical outcomes are unknown.

Objectives

To assess if Lp(a) associates with lower tPA activity in COVID-19 patients, and how in COVID-19 populations Lp(a) and tPA change post infection.

Methods

Endogenous tPA enzymatic activity, tPA or Lp(a) concentration were measured in plasma from hospitalized patients with and without COVID-19. The association between plasma tPA and adverse clinical outcomes was assessed.

Results

In hospitalized patients with COVID-19, we found lower tPA enzymatic activity and higher plasma Lp(a) than that in non-COVID-19 controls. During hospitalization, Lp(a) increased and tPA activity decreased, which associates with mortality. Among those who survived, Lp(a) decreased and tPA enzymatic activity increased during recovery. In patients with COVID-19, tPA activity is inversely correlated with tPA concentrations, thus, in another larger COVID-19 cohort, we utilized plasma tPA concentration as a surrogate to inversely reflect tPA activity. The tPA concentration was positively associated with death, disease severity, plasma inflammatory, and prothrombotic markers, and with length of hospitalization among those who were discharged.

Conclusion

High Lp(a) concentration provides a possible explanation for low endogenous tPA enzymatic activity, and poor clinical outcomes in patients with COVID-19.

Ancestral diversity in lipoprotein(a) studies helps address evidence gaps

INTRODUCTION

The independent and causal cardiovascular disease risk factor lipoprotein(a) (Lp(a)) is elevated in >1.5 billion individuals worldwide, but studies have prioritised European populations.

METHODS

Here, we examined how ancestrally diverse studies could clarify Lp(a)'s genetic architecture, inform efforts examining application of Lp(a) polygenic risk scores (PRS), enable causal inference and identify unexpected Lp(a) phenotypic effects using data from African (n=25 208), East Asian (n=2895), European (n=362 558), South Asian (n=8192) and Hispanic/Latino (n=8946) populations.

RESULTS

Fourteen genome-wide significant loci with numerous population specific signals of large effect were identified that enabled construction of Lp(a) PRS of moderate (R2=15% in East Asians) to high (R2=50% in Europeans) accuracy. For all populations, PRS showed promise as a 'rule out' for elevated Lp(a) because certainty of assignment to the low-risk threshold was high (88.0%-99.9%) across PRS thresholds (80th-99th percentile). Causal effects of increased Lp(a) with increased glycated haemoglobin were estimated for Europeans (p value =1.4×10-6), although inverse effects in Africans and East Asians suggested the potential for heterogeneous causal effects. Finally, Hispanic/Latinos were the only population in which known associations with coronary atherosclerosis and ischaemic heart disease were identified in external testing of Lp(a) PRS phenotypic effects.

CONCLUSIONS

Our results emphasise the merits of prioritising ancestral diversity when addressing Lp(a) evidence gaps.

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.

Association of statin use and increase in lipoprotein(a): a real-world database research

BACKGROUND

There is an increased concern that statins may have an unintended effect of elevated lipoprotein(a) [Lp(a)]. We conducted a large sample real-world study to test the association.

METHODS

This retrospective cohort study was conducted using data from an integrated SuValue database, which includes 221 hospitals across China covering more than 200,000 of population with longitudinal follow-up to 10 years. Propensity score matching was applied to identify two comparable cohorts with statin users and non-statin users. Detailed follow-up information such as Lp(a) levels were extracted. The hazard ratio was calculated on Lp(a) changes based on the statin usage cohorts. Detailed subgroup and different characteristic cohorts' analyses were also conducted.

RESULTS

After baseline propensity score matching, a total of 42,166 patients were included in a 1:1 matched ratio between statin users and non-statin users. In the case of no difference in low density lipoprotein (LDL-C), Lp(a) was increased significantly with the use of statins (adjusted HR 1.47; 95% confidence interval [CI] 1.43-1.50). Lp(a) increase was observed in various subgroup analyses and different cohorts. The dose intensity of statin was positively associated with the evaluated Lp(a) level.

CONCLUSION

The use of statins was associated with an increased risk of Lp(a) elevation compared with non-statin use counterparts. The clinical relevance of these increases needs to be addressed in surrogate marker trials and/or large, cardiovascular outcomes trials.

Lack of significant associations between single nucleotide polymorphisms in LPAL2-LPA genetic region and all cancer incidence and mortality in Japanese population: The Japan public health center-based prospective study

BACKGROUND

High lipoprotein (a) level is an established cardiovascular risk, but its association with non-cardiovascular diseases, especially cancer, is controversial. Serum lipoprotein (a) levels vary widely by genetic backgrounds and are largely determined by the genetic variations of apolipoprotein (a) gene, LPA. In this study, we investigate the association between SNPs in LPA region and cancer incidence and mortality in Japanese.

METHODS

A genetic cohort study was conducted utilizing the data from 9923 participants in the Japan Public Health Center-based Prospective Study (JPHC Study). Twenty-five SNPs in the LPAL2-LPA region were selected from the genome-wide genotyped data. Cox regression analysis adjusted for the covariates and competing risks of death from other causes, were used to estimate the relative risk (hazard ratios (HR) with 95% confidence intervals (CI)) of overall and site-specific cancer incidence and mortality, for each SNP.

RESULTS

No significant association was found between SNPs in the LPAL2-LPA region and cancer incidence or mortality (overall/site-specific cancer). In men, however, HRs for stomach cancer incidence of 18SNPs were estimated higher than 1.5 (e.g., 2.15 for rs13202636, model free, 95%CI: 1.28-3.62) and those for stomach cancer mortality of 2SNPs (rs9365171, rs1367211) were estimated 2.13 (recessive, 95%CI:1.04-4.37) and 1.61 (additive, 95%CI: 1.00-2.59). Additionally, the minor allele for SNP rs3798220 showed increased death risk from colorectal cancer (CRC) in men (HR: 3.29, 95% CI:1.59 - 6.81) and decreased CRC incidence risk in women (HR: 0.46, 95%CI: 0.22-0.94). Minor allele carrier of any of 4SNPs could have risk of prostate cancer incidence (e.g., rs9365171 dominant, HR: 1.71, 95%CI: 1.06-2.77).

CONCLUSIONS

None of the 25 SNPs in the LPAL2-LPA region was found to be significantly associated with cancer incidence or mortality. Considering the possible association between SNPs in LPAL2-LPA region and colorectal, prostate and stomach cancer incidence or mortality, further analysis using different cohorts is warranted.

Advances and Challenges for GWAS Analysis in Cardiac Diseases: A Focus on Coronary Artery Disease (CAD)

The achievement of genome-wide association studies (GWAS) has rapidly progressed our understanding of the etiology of coronary artery disease (CAD). It unlocks new strategies to strengthen the stalling of CAD drug development. In this review, we highlighted the recent drawbacks, mainly pointing out those involved in identifying causal genes and interpreting the connections between disease pathology and risk variants. We also benchmark the novel insights into the biological mechanism behind the disease primarily based on outcomes of GWAS. Furthermore, we also shed light on the successful discovery of novel treatment targets by introducing various layers of "omics" data and applying systems genetics strategies. Lastly, we discuss in-depth the significance of precision medicine that is helpful to improve through GWAS analysis in cardiovascular research.

Lipoprotein(a), Oxidized Phospholipids, and Coronary Artery Disease Severity and Outcomes

BACKGROUND

Lipoprotein(a) (Lp[a]) and oxidized phospholipids (OxPLs) are each independent risk factors for atherosclerotic cardiovascular disease. The extent to which Lp(a) and OxPLs predict coronary artery disease (CAD) severity and outcomes in a contemporary, statin-treated cohort is not well established.

OBJECTIVES

This study sought to evaluate the relationships between Lp(a) particle concentration and OxPLs associated with apolipoprotein B (OxPL-apoB) or apolipoprotein(a) (OxPL-apo[a]) with angiographic CAD and cardiovascular outcomes.

METHODS

Among 1,098 participants referred for coronary angiography in the CASABLANCA (Catheter Sampled Blood Archive in Cardiovascular Diseases) study, Lp(a), OxPL-apoB, and OxPL-apo(a) were measured. Logistic regression estimated the risk of multivessel coronary stenoses by Lp(a)-related biomarker level. Cox proportional hazards regression estimated the risk of major adverse cardiovascular events (MACEs) (coronary revascularization, nonfatal myocardial infarction, nonfatal stroke, and cardiovascular death) in follow-up.

RESULTS

Median Lp(a) was 26.45 nmol/L (IQR: 11.39-89.49 nmol/L). Lp(a), OxPL-apoB, and OxPL-apo(a) were highly correlated (Spearman R ≥0.91 for all pairwise combinations). Lp(a) and OxPL-apoB were associated with multivessel CAD. Odds of multivessel CAD per doubling of Lp(a), OxPL-apoB, and OxPL-apo(a) were 1.10 (95% CI: 1.03-1.18; P = 0.006), 1.18 (95% CI: 1.03-1.34; P = 0.01), and 1.07 (95% CI: 0.99-1.16; P = 0.07), respectively. All biomarkers were associated with cardiovascular events. HRs for MACE per doubling of Lp(a), OxPL-apoB, and OxPL-apo(a) were 1.08 (95% CI: 1.03-1.14; P = 0.001), 1.15 (95% CI: 1.05-1.26; P = 0.004), and 1.07 (95% CI: 1.01-1.14; P = 0.02), respectively.

CONCLUSIONS

In patients undergoing coronary angiography, Lp(a) and OxPL-apoB are associated with multivessel CAD. Lp(a), OxPL-apoB, and OxPL-apo(a) are associated with incident cardiovascular events. (Catheter Sampled Blood Archive in Cardiovascular Diseases [CASABLANCA]; NCT00842868).

Thrombophilia screening in the routine clinical care of children with arterial ischemic stroke

BACKGROUND

Current guidelines recommend thrombophilia evaluation in childhood arterial ischemic stroke, but the impact of screening on management is unknown. The objective of the current study is to report the incidence of thrombophilia identified as part of routine clinical care in the context of available literature reports, and to describe the impact of a diagnosis of thrombophilia on patient management.

METHODS

We conducted a single-institution retrospective chart review for all children with arterial ischemic stroke occurring between January 1, 2009 and January 1, 2021. We collected thrombophilia screening results, stroke etiology, and management. We also reviewed the literature of thrombophilia testing in childhood arterial ischemic stroke published prior to June 30, 2022. Meta-analysis methods were used to assess prevalence rates.

RESULTS

Among children with thrombophilia testing performed, 5% (six of 122 patients) were factor V Leiden heterozygous, 1% (one of 102 patients) were prothrombin gene mutation heterozygous, 1% (one of 122) had protein S deficiency, 20% (23/116 patients) had elevated lipoprotein(a), 3% (three of 110 patients) had elevated homocysteine levels, and 9% (10/112) had elevated antiphospholipid antibodies, only two of whom had persistently elevated levels. There was no change in stroke therapy due to these results. Literature review revealed a wide range of prevalence for most thrombophilia traits, with high cross-study heterogeneity in most cases.

CONCLUSIONS

The rates of thrombophilia in our cohort were consistent with that expected in the general population. The identification of thrombophilia did not alter stroke care. However, some of the results were actionable, prompting evaluation for lipid disorders and patient-specific counseling on cardiovascular risk and risk for venous thrombosis.

Pharmacotherapy in familial hypercholesterolemia - Current state and emerging paradigms

Familial hypercholesterolemia is a highly prevalent but underdiagnosed disease marked by increased risk of cardiovascular morbidity and mortality. Aggressive reduction of LDL-cholesterol is a hallmark of cardiovascular risk mitigation in familial hypercholesterolemia. More recently, we have witnessed an expanded repertoire of pharmacologic agents that directly target LDL-cholesterol and/or reduce heart disease burden. In this state-of-the-art review, we explore the development, clinical efficacy and limitations of existing and potential future therapeutics in familial hypercholesterolemia.

Multiancestry Genome-Wide Association Study of Aortic Stenosis Identifies Multiple Novel Loci in the Million Veteran Program

BACKGROUND

Calcific aortic stenosis (CAS) is the most common valvular heart disease in older adults and has no effective preventive therapies. Genome-wide association studies (GWAS) can identify genes influencing disease and may help prioritize therapeutic targets for CAS.

METHODS

We performed a GWAS and gene association study of 14 451 patients with CAS and 398 544 controls in the Million Veteran Program. Replication was performed in the Million Veteran Program, Penn Medicine Biobank, Mass General Brigham Biobank, BioVU, and BioMe, totaling 12 889 cases and 348 094 controls. Causal genes were prioritized from genome-wide significant variants using polygenic priority score gene localization, expression quantitative trait locus colocalization, and nearest gene methods. CAS genetic architecture was compared with that of atherosclerotic cardiovascular disease. Causal inference for cardiometabolic biomarkers in CAS was performed using Mendelian randomization and genome-wide significant loci were characterized further through phenome-wide association study.

RESULTS

We identified 23 genome-wide significant lead variants in our GWAS representing 17 unique genomic regions. Of the 23 lead variants, 14 were significant in replication, representing 11 unique genomic regions. Five replicated genomic regions were previously known risk loci for CAS (PALMD, TEX41, IL6, LPA, FADS) and 6 were novel (CEP85L, FTO, SLMAP, CELSR2, MECOM, CDAN1). Two novel lead variants were associated in non-White individuals (P<0.05): rs12740374 (CELSR2) in Black and Hispanic individuals and rs1522387 (SLMAP) in Black individuals. Of the 14 replicated lead variants, only 2 (rs10455872 [LPA], rs12740374 [CELSR2]) were also significant in atherosclerotic cardiovascular disease GWAS. In Mendelian randomization, lipoprotein(a) and low-density lipoprotein cholesterol were both associated with CAS, but the association between low-density lipoprotein cholesterol and CAS was attenuated when adjusting for lipoprotein(a). Phenome-wide association study highlighted varying degrees of pleiotropy, including between CAS and obesity at the FTO locus. However, the FTO locus remained associated with CAS after adjusting for body mass index and maintained a significant independent effect on CAS in mediation analysis.

CONCLUSIONS

We performed a multiancestry GWAS in CAS and identified 6 novel genomic regions in the disease. Secondary analyses highlighted the roles of lipid metabolism, inflammation, cellular senescence, and adiposity in the pathobiology of CAS and clarified the shared and differential genetic architectures of CAS with atherosclerotic cardiovascular diseases.

Impact of Lipoprotein(a) on Macrovascular Complications of Diabetes in a Multiethnic Population in the French Amazon

BACKGROUND AND AIMS

In French Guiana, the prevalence of diabetes is around 10%, and cardio and neurovascular pathologies are the first medical cause of early mortality. Lipoprotein(a) (Lp(a)) is described in the literature as a risk factor independent of other cardiovascular risk factors, but there are important interindividual differences, especially according to ethnicity. The objective of this study was to investigate the association of Lp(a) and macrovascular complications in a multiethnic population of patients with diabetes in the French Amazon.

MATERIALS AND METHODS

Since May 2019, 1243 patients were screened 806 of whom had Lp(a) determination. We compared the prevalence of macrovascular complications in three groups according to Lp(a) concentration: between 0 and 75 mg/mL, between 76 and 300 mg/mL, and >300 mg/mL.

RESULTS

712 patients in the study had type 2 diabetes (88.34% of the sample). A history of hypertension was significantly associated with greater Lp(a) levels. Lp(a) concentration was greater among Creole ethnic groups. No association was found between Lp(a) levels and macrovascular complications in the Lp(a) > 300 mg/mL group.

CONCLUSIONS

These results do not replicate findings in mostly Caucasian populations suggesting that the Lp(a) threshold for, or the link with, cardiovascular risk may be different given the predominantly African origin of the French Guianese population. Further studies should study genetic polymorphisms in our population.

Rare Variants in Genes of the Cholesterol Pathway Are Present in 60% of Patients with Acute Myocardial Infarction

Acute myocardial infarction (AMI) is a pandemic in which conventional risk factors are inadequate to detect who is at risk early in the asymptomatic stage. Although gene variants in genes related to cholesterol, which may increase the risk of AMI, have been identified, no studies have systematically screened the genes involved in this pathway. In this study, we included 105 patients diagnosed with AMI with an elevation of the ST segment (STEMI) and treated with primary percutaneous coronary intervention (PPCI). Using next-generation sequencing, we examined the presence of rare variants in 40 genes proposed to be involved in lipid metabolism and we found that 60% of AMI patients had a rare variant in the genes involved in the cholesterol pathway. Our data show the importance of considering the wide scope of the cholesterol pathway in order to assess the genetic risk related to AMI.

LPA disruption with AAV-CRISPR potently lowers plasma apo(a) in transgenic mouse model: A proof-of-concept study

Lipoprotein(a) (Lp(a)) represents a unique subclass of circulating lipoprotein particles and consists of an apolipoprotein(a) (apo(a)) molecule covalently bound to apolipoprotein B-100. The metabolism of Lp(a) particles is distinct from that of low-density lipoprotein (LDL) cholesterol, and currently approved lipid-lowering drugs do not provide substantial reductions in Lp(a), a causal risk factor for cardiovascular disease. Somatic genome editing has the potential to be a one-time therapy for individuals with extremely high Lp(a). We generated an LPA transgenic mouse model expressing apo(a) of physiologically relevant size. Adeno-associated virus (AAV) vector delivery of CRISPR-Cas9 was used to disrupt the LPA transgene in the liver. AAV-CRISPR nearly completely eliminated apo(a) from the circulation within a week. We performed genome-wide off-target assays to determine the specificity of CRISPR-Cas9 editing within the context of the human genome. Interestingly, we identified intrachromosomal rearrangements within the LPA cDNA in the transgenic mice as well as in the LPA gene in HEK293T cells, due to the repetitive sequences within LPA itself and neighboring pseudogenes. This proof-of-concept study establishes the feasibility of using CRISPR-Cas9 to disrupt LPA in vivo, and highlights the importance of examining the diverse consequences of CRISPR cutting within repetitive loci and in the genome globally.

Circulating lipoprotein(a) levels and health outcomes: Phenome-wide Mendelian randomization and disease-trajectory analyses

BACKGROUND

Lipoprotein(a) [Lp(a)] is a risk factor for atherosclerotic and valvular diseases, but its possible role in other diseases has not yet been established. We conducted phenome-wide Mendelian randomization and disease-trajectory analyses to assess any associations of circulating Lp(a) levels with a broad range of diseases.

METHODS

A weighted polygenic risk score was constructed using independent genetic variants in the LPA gene and with an established effect on Lp(a) levels. The PheWAS analysis included 1081 phenotype outcomes ascertained among 385,917 White participants of the UK Biobank. Novel findings were investigated in MR analysis using data from the FinnGen consortium. Disease-trajectory and comorbidity analyses were further conducted to explore the sequential patterns of multiple morbidities related to high circulating Lp(a) levels.

RESULTS

PheWAS revealed statistically significant associations of higher circulating Lp(a) levels with increased risk of a large number of circulatory system diseases (including various cardiac diseases, peripheral vascular disease, hypertension, and valvular and cerebrovascular diseases) as well as some endocrine/metabolic diseases (including hyperlipidemia, hypercholesterolemia, disorders of lipoid metabolism, and type 2 diabetes), genitourinary system diseases (renal failure), and hematologic diseases (including different types of anemia). Two-sample MR analysis supported the association between Lp(a) and risk of anemia, showed a suggestive association with type 2 diabetes, but found no association with renal failure. Disease-trajectory and comorbidity analyses identified 3 major sequential patterns of multiple morbidities, mainly in the cardiovascular, metabolic, and mental disorders, related to high circulating Lp(a) levels.

CONCLUSIONS

Genetically predicted higher circulating Lp(a) levels were associated with increased risk of many circulatory system diseases and anemia. Additionally, this study identified three major sequential patterns of multiple morbidities related to high Lp(a).

Hyperlipoproteinemia(a) and Severe Coronary Artery Lesion Types

Diffuse atherosclerosis and calcification of the coronary arteries (CA) create serious difficulties for coronary artery bypass grafting (CABG). The aim of this study was to compare demographic indicators, lipids, and clinical results one year after CABG in patients with different phenotypes of coronary artery (CA) disease. In total, 390 patients hospitalized for elective CABG were included in a single-center prospective study. Demographic data, lipids (total, low-density lipoprotein and high-density lipoprotein cholesterol, and triglycerides), and lipoprotein(a) (Lp(a)) concentrations were analyzed for all patients. Major adverse cardiovascular events (MACE) included myocardial infarction, stroke, percutaneous coronary intervention, and death from cardiac causes within one year after surgery. No significant outcome differences were found between the groups with diffuse vs. segmental lesions, nor the groups with and without calcinosis for all studied parameters except for Lp(a). Median Lp(a) concentrations were higher in the group of patients with diffuse compared to segmental lesions (28 vs. 16 mg/dL, p = 0.023) and in the group with calcinosis compared to the group without it (35 vs. 19 mg/dL, p = 0.046). Lp(a) ≥ 30 mg/dL was associated with the presence of diffuse lesions (OR = 2.18 (95% CI 1.34–3.54), p = 0.002), calcinosis (2.15 (1.15–4.02), p = 0.02), and its combination (4.30 (1.81–10.19), p = 0.0009), irrespective of other risk factors. The risk of MACE within one year after CABG was higher for patients with combined diffuse and calcified lesions vs. patients with a segmental lesion without calcinosis (relative risk = 2.38 (1.13–5.01), p = 0.02). Conclusion: Diffuse atherosclerosis and coronary calcinosis are associated with elevated Lp(a) levels, independent of other risk factors. The risk of MACE in the first year after surgery is significantly higher in patients with diffuse atherosclerosis and coronary calcinosis, which should be considered when prescribing postoperative treatment for such patients.

Lp(a), oxidized phospholipids and oxidation-specific epitopes are increased in subjects with keloid formation

BACKGROUND

Keloid formation following trauma or surgery is common among darkly pigmented individuals. Since lipoprotein(a) [Lp(a)] has been postulated to have a putative role in wound healing, and also mediates atherosclerotic cardiovascular disease, it was assessed whether Lp(a), its associated oxidized phospholipids and other oxidation-specific biomarkers were associated with keloid formation.

METHODS

This case-control study included darkly pigmented individuals of African ancestry, 100 with keloid scarring and 100 non-keloid controls. The lipid panel, hsCRP, Lp(a), oxidized phospholipids on apolipoprotein B-100 (OxPL-apoB), IgG and IgM apoB-immune complexes and IgG and IgM autoantibodies to a malondialdehyde mimotope (MDA-mimotope) were measured. Immunohistochemistry of keloid specimens was performed for both Lp(a) and OxPL staining.

RESULTS

Cases and controls were well matched for age, sex and lipid profile. Mean Lp(a) (57.8 vs. 44.2 mg/dL; P = 0.01, OxPL-apoB 17.4 vs. 15.7 nmol/L; P = 0.009) and IgG and IgM apoB-immune complexes and IgG and IgM MDA-mimotope levels were significantly higher in keloid cases. Keloid tissue stained strongly for OxPL.

CONCLUSION

Darkly pigmented individuals of African ancestry with keloids have higher plasma levels of Lp(a), OxPL-apoB and oxidation-specific epitopes. The commonality of excessive wound healing in keloids and chronic complications from coronary revascularization suggests avenues of investigation to define a common mechanism driven by Lp(a) and the innate response to oxidized lipids.

Review of recent clinical trials and their impact on the treatment of hypercholesterolemia

PURPOSE OF REVIEW

Cardiovascular disease is the leading cause of death in the United States with incidence expected to increase in the coming decades. Recent years have produced a variety of new and novel therapeutics aimed at reducing the global burden of cardiovascular disease. This review highlights these recent advancements.

RECENT FINDINGS

In addition to more rigorous therapeutic thresholds for traditional LDL lowering agents such as statins, recent studies have developed new pathways of lipid lowering for both typical cardiovascular disease and complex, genetic lipid disorders. This includes inhibition of the cholesterol synthesis enzyme ATP citrate lyase with bempedoic acid, prevention of PCSK9 mRNA translation with inclisiran, inhibition of the lipoprotein lipase inhibitor angiopoetin like 3 protein with evinacumab and the use of anti-sense oligonucleotides to lower lipoprotein(a) levels. Icosapent ethyl, while remaining a topic of debate and controversy, demonstrates efficacy in cardiovascular risk reduction when all available data are examined. Lastly fibrate therapy continues to produce negative results in terms of cardiovascular disease reduction.

SUMMARY

Recent years have yielded breadth and depth to cardiovascular treatments. This expanded armamentarium will allow for more effective and more consistent treatment and prevention of cardiovascular disease.

Causal associations between disorders of lipoprotein metabolism and ten cardiovascular diseases

Disorders of lipoprotein metabolism have been linked with an increased risk of cardiovascular diseases (CVDs) but the causal association is unclear. In this study, we investigated the causal association between disorders of lipoprotein metabolism and CVDs using two-sample Mendelian randomization (MR). The exposure was obtained from Finn genome-wide association studies (14,010 cases, 197,259 controls), and the corresponding CVDs were extracted from the largest published genome-wide association studies. A random-effects inverse-variance weighted method was used for the main analyses with a complementary analysis using the weighted median and MR-Egger approaches. Multiple sensitivity analyses were performed to assess horizontal pleiotropy. The MR analysis indicated positive associations of disorders of lipoprotein metabolism with coronary artery disease (odds ratio [OR] 1.670, 95% confidence interval [CI] 1.373–2.031; p < 0.001), aortic aneurysm (OR 1.394, 95% CI 1.199–1.619; p < 0.001), heart failure (OR 1.20, 95% CI 1.115–1.294; p < 0.001), hypertension (OR 1.011, 95% CI 1.006–1.091; p < 0.001), old myocardial infarction (OR 1.004, 95% CI 1.002–1.007; p = 0.001), and stroke (OR 1.002, 95% CI 1.001–1.003; p = 0.002). There is a suggestive causal relationship between disorders of lipoprotein metabolism and atrial fibrillation (OR 1.047, 95% CI 1.006–1.091; p = 0.026) and acute myocardial infarction (OR 1.003, 95% CI 1.001–1.005; p = 0.012). There was limited evidence of a causal association between disorders of lipoprotein metabolism and peripheral vascular disease and venous thromboembolism. Our findings indicate a significant causal association between disorders of lipoprotein metabolism and many CVDs, including coronary artery disease, aortic aneurysm, heart failure, hypertension, old myocardial infarction, and stroke. These associations may be useful for development of treatment strategies that regulate lipoprotein metabolism in patients with CVD.

Lipoprotein(a) in atherosclerotic cardiovascular disease and aortic stenosis: a European Atherosclerosis Society consensus statement

This 2022 European Atherosclerosis Society lipoprotein(a) [Lp(a)] consensus statement updates evidence for the role of Lp(a) in atherosclerotic cardiovascular disease (ASCVD) and aortic valve stenosis, provides clinical guidance for testing and treating elevated Lp(a) levels, and considers its inclusion in global risk estimation. Epidemiologic and genetic studies involving hundreds of thousands of individuals strongly support a causal and continuous association between Lp(a) concentration and cardiovascular outcomes in different ethnicities; elevated Lp(a) is a risk factor even at very low levels of low-density lipoprotein cholesterol. High Lp(a) is associated with both microcalcification and macrocalcification of the aortic valve. Current findings do not support Lp(a) as a risk factor for venous thrombotic events and impaired fibrinolysis. Very low Lp(a) levels may associate with increased risk of diabetes mellitus meriting further study. Lp(a) has pro-inflammatory and pro-atherosclerotic properties, which may partly relate to the oxidized phospholipids carried by Lp(a). This panel recommends testing Lp(a) concentration at least once in adults; cascade testing has potential value in familial hypercholesterolaemia, or with family or personal history of (very) high Lp(a) or premature ASCVD. Without specific Lp(a)-lowering therapies, early intensive risk factor management is recommended, targeted according to global cardiovascular risk and Lp(a) level. Lipoprotein apheresis is an option for very high Lp(a) with progressive cardiovascular disease despite optimal management of risk factors. In conclusion, this statement reinforces evidence for Lp(a) as a causal risk factor for cardiovascular outcomes. Trials of specific Lp(a)-lowering treatments are critical to confirm clinical benefit for cardiovascular disease and aortic valve stenosis.

Serum lipoprotein(a) and 3-year outcomes in patients undergoing percutaneous coronary intervention

BACKGROUND AND AIMS

We aimed at addressing the association between serum lipoprotein (a) levels and clinical outcomes of consecutive patients undergoing PCI.

METHODS

We used consecutive patients undergoing PCI at the Heart Center University of Freiburg, Bad Krozingen in Germany between January 2005 and November 2013. A total of 6679 patients [men (n = 5391) and women (n = 1288)] mean aged 67.5 (± 11.1) years were assessed at baseline and prospectively followed for 3 years. Lp(a) measurement were performed at hospital admission as a routine laboratory parameter.

RESULTS

Approximately 30% of PCI patients show an elevated Lp(a) value of more than 50mg/dL. In total, 736 Patients died during the follow-up, thereof 189 (11.3%) in the first quartile, 186 (10.7%) in the second quartile, 183 (11.5%) in the third quartile and 178 (10.7%) in the last quartile (p value 0.843 from LogRank test). The MACE rate showed consistent results with 409 (24.4%), 385 (22.1%), 395 (24.7%) and 419 (25.3%) in the different respective quartiles (p value 0.125 from LogRank test).

CONCLUSION

In this large non-selected cohort of patients undergoing PCI followed by moderate intensity statin therapy, higher Lp(a) levels were not associated with worse clinical outcomes during a follow-up of 3 years.

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).

Risk factors profile of young and older patients with myocardial infarction

Myocardial infarction (MI) among young adults (<45 years) represents a considerable proportion of the total heart attack incidents. The underlying pathophysiologic characteristics, atherosclerotic plaque features, and risk factors profile differ between young and older patients with MI. This review article discusses the main differences between the younger and elderly MI patients as well as the different pathogenic mechanisms underlying the development of MI in the younger. Young patients with MI often have eccentric atherosclerotic plaques with inflammatory features but fewer lesions, and are more likely to be smokers, obese, and have poor lifestyle, such as inactivity and alcohol intake. Compared to older MI patients, younger are more likely to be men, have familial-combined hyperlipidaemia and increased levels of lipoprotein-a. In addition, MI in younger patients may be related to use of cannabis, cocaine use, and androgenic anabolic steroids. Genomic differences especially in the pathways of coagulation and lipid metabolism have also been identified between young and older patients with MI. Better understanding of the risk factors and the anatomic and pathophysiologic processes in young adults can improve MI prevention and treatment strategies in this patient group. Awareness could help identify young subjects at increased risk and guide primary prevention strategies. Additional studies focusing on gene pathways related to lipid metabolism, inflammation, and coagulation are needed.

Lipoprotein(a) in systemic lupus erythematosus is associated with history of proteinuria and reduced renal function

OBJECTIVE

Proteinuria is the clinical expression of lupus nephritis and despite recent advances in the therapeutic armamentarium for lupus nephritis, morbidity and mortality rates remain high. Therefore, the identification of factors that predict lupus nephritis is paramount in preventing damage accrual and disease progression. Lipoprotein (a) (Lp[a]) is a primarily genetically inherited plasma lipoprotein with pro-thrombotic and pro-atherosclerotic effects. Elevated Lp(a) has been observed at early stages of renal impairment in the general population and is associated with the development of chronic kidney disease. However, little is known about renal implications of Lp(a) in SLE. Thus, we evaluated Lp(a) and atherosclerotic events, thrombotic events, renal disease, and disease activity in patients with SLE.

METHODS

SLE patients fulfilling the revised American College of Rheumatology (ACR) or SLICC classification criteria with a measurement of Lp(a) were included in the analysis. A cutoff of 125 nmol/L was chosen based on expert opinion. Chi-square test was used to compare the differences between patient characteristics and Lp(a) levels. Logistic regression or linear regression were used, where appropriate, to assess the association between Lp(a) values and the measured outcomes.

RESULTS

Lp(a) levels from 562 patients were analyzed. There was an association between elevated Lp(a) and a history of proteinuria (OR 1.58, p-value = 0.02). This association remained significant following adjustment for age, sex, race, low C3, and elevated anti-dsDNA (OR = 1.55, p-value = 0.04). There was also an association with eGFR < 60 (p = 0.02). Patients with elevated Lp(a) had higher physician global activity (p = 0.01) and erythrocyte sediment rate (p = 0.03).

CONCLUSION

Elevated Lp(a) was associated with proteinuria, independent of known factors associated with lupus proteinuria, as well as reduced eGFR and physician global activity. Our findings highlight the potential role of Lp(a) as a noninvasive biomarker for early renal disease in SLE.

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.