Lipoprotein (a) as a cause of cardiovascular disease: insights from epidemiology, genetics, and biology

Low Molecular Weight Apolipoprotein(a) Phenotype Rather Than Lipoprotein(a) Is Associated With Coronary Atherosclerosis and Myocardial Infarction

Background and Aims

Current evidence suggests that lipoprotein(a) [Lp(a)] level above 50 mg/dL is associated with increased cardiovascular risk. Our study aim was to determine the relationship of apolipoprotein(a) [apo(a)] phenotypes and Lp(a) concentration below and above 50 mg/dL with coronary atherosclerosis severity and myocardial infarction (MI).

Material and Methods

The study population consisted of 540 patients (mean age 54.0 ± 8.8 years, 82% men) who passed through coronary angiography. The number of diseased major coronary arteries assessed atherosclerosis severity. Lipids, glucose, Lp(a) levels and apo(a) phenotypes were determined in all patients. All patients were divided into four groups: with Lp(a) <50 mg/dL [ “normal” Lp(a)] or ≥50 mg/dL [hyperLp(a)], and with low-molecular (LMW) or high-molecular weight (HMW) apo(a) phenotypes.

Results

Baseline clinical and biochemical characteristics were similar between the groups. In groups with LMW apo(a) phenotypes, the odds ratio (OR; 95% confidence interval) of multivessel disease was higher [10.1; 3.1–33.5, p < 0.005 for hyperLp(a) and 2.2; 1.0–4.9, p = 0.056 for normal Lp(a)], but not in the group with HMW apo(a) and hyperLp(a) [1.1; 0.3–3.3, p = 0.92] compared with the reference group with HMW apo(a) and normal Lp(a). Similarly, MI was observed more often in patients with LMW apo(a) phenotype and hyperLp(a) and normal Lp(a) than in groups with HMW apo(a) phenotype.

Conclusion

The LMW apo(a) phenotype is associated with the severity of coronary atherosclerosis and MI even when Lp(a) level is below 50 mg/dL. The combination of Lp(a) level above 50 mg/dL and LMW apo(a) phenotype increases the risk of severe coronary atherosclerosis, regardless of other risk factors.

Genetic Lipid Disorders Associated with Atherosclerotic Cardiovascular Disease: Molecular Basis to Clinical Diagnosis and Epidemiologic Burden

Genetic lipid disorders, ranging from common dyslipidemias such as familial hypercholesterolemia, lipoprotein (a), and familial combined hyperlipidemia to rare disorders including familial chylomicronemia syndrome and inherited hypoalphalipoproteinemias (ie, Tangier and fish eye diseases), affect millions of individuals in the United States and tens of millions around the world and are often undiagnosed in the general population. Clinicians should take into consideration the potential of inherited lipid disorders or syndromes when severe derangements in lipid parameters are observed. Patients' combined genotype and phenotype should be evaluated in conjunction with a host of environmental factors impacting their risk of atherosclerotic cardiovascular disease.

Lipoprotein(a) and Pulmonary Embolism Severity-A Retrospective Data Analysis

Aim

We aimed to investigate a correlation between PE severity and Lp(a) levels.

Methods

We performed a retrospective data analysis from our medical records of PE patients admitted to the University Hospital Graz, Austria. Patients with an Lp(a) reading within a 1-year interval before and after PE diagnosis were included. In accordance with the 2019 ESC guidelines for the diagnosis and management of acute PE, severity assessment was carried out classifying patients into four groups: low risk (LR), intermediate low risk (IML), intermediate high risk (IMH) and high risk (HR). The study period of interest was between January 1, 2002 and August 1, 2020.

Results

We analyzed 811 patients with PE, of whom 323 (40%) had low-risk PE, 343 (42%) had intermediate-low-risk PE, 64 (8%) had intermediate-high-risk PE, and 81 (10%) had high-risk PE, respectively. We did not observe an association between PE severity and Lp(a) concentrations. In detail, median Lp(a) concentrations were 17 mg/dL [25–75th percentile: 10-37] in low-risk PE patients, 16 mg/dL [10–37] in intermediate-low-risk PE patients, 15mg/dL [10–48] in intermediate-high-risk PE patients, and 13mg/dL [10–27] in high-risk PE patients, respectively (Kruskal-Wallis p = 0.658, p for linear trend = 0.358).

Conclusion

The current findings suggest no correlation between PE severity and Lp(a) levels.

Lipoprotein(a) as Part of the Diagnosis of Clinical Familial Hypercholesterolemia

PURPOSE OF REVIEW

Individuals with familial hypercholesterolemia have very high risk of cardiovascular disease due to lifelong elevations in LDL cholesterol. Elevated lipoprotein(a) is a risk factor for cardiovascular diseases such as myocardial infarction and aortic valve stenosis. It has been proposed to include elevated lipoprotein(a) in the diagnosis of clinical familial hypercholesterolemia.

RECENT FINDINGS

Lipoprotein(a) is co-measured in LDL cholesterol, and up to one-quarter of all diagnoses of clinical familial hypercholesterolemia are due to high levels of lipoprotein(a). Further, individuals with both familial hypercholesterolemia and elevated lipoprotein(a) have an extremely high risk of myocardial infarction. We discuss the background for familial hypercholesterolemia and elevated lipoprotein(a) as risk factors for cardiovascular disease and the consequences of the fact that LDL cholesterol measurements/calculations include the cholesterol present in lipoprotein(a). Finally, we discuss the potential of including lipoprotein(a) as part of the diagnosis of familial hypercholesterolemia and in consequence possible treatments.

Impact of lipoprotein(a) level on cardiometabolic disease in the Chinese population: The CHCN-BTH Study

BACKGROUND

The emergence of promising compounds to lower lipoprotein(a) [Lp(a)] has increased the need for a precise characterisation and comparability assessment of Lp(a)-associated cardiometabolic disease risk. This study aimed to evaluate the distribution of Lp(a) levels in a Chinese population and characterise the association with cardiometabolic diseases.

METHODS

We assessed data from individuals from the Cohort Study on Chronic Diseases of the General Community Population in the Beijing-Tianjin-Hebei Region project. All Lp(a) measurements were performed in the same hospital. The cardiometabolic diseases considered were coronary heart disease (CHD), stroke, hypertension and type 2 diabetes (T2DM).

RESULTS

A total of 25343 individuals were included in the study. The median level of Lp(a) was 11.9 mg/dl (IQR 5.9 to 23.7 mg/dl), and higher Lp(a) levels showed a significant concentration-dependent association with CHD risk. Individuals with Lp(a) levels lower than the 25th percentile were at increased risk of hypertension (OR: 1.15, 95% CI: 1.06-1.25) and T2DM (OR: 1.15, 95% CI: 1.03-1.28); however, Lp(a) levels were not significantly associated with stroke. The addition of Lp(a) levels to the prognostic model led to a marginal but significant C-index, integrated discrimination improvement and net reclassification improvement.

CONCLUSIONS

In this large sample size study, we observed that elevated Lp(a) levels were significantly associated with CHD. Furthermore, we found that the lowest Lp(a) levels were also significantly associated with hypertension and T2DM. These results provide evidence for differential approaches to higher levels of Lp(a) in individuals with different cardiometabolic diseases.

Performance comparison of different classification algorithms applied to the diagnosis of familial hypercholesterolemia in paediatric subjects

Familial Hypercholesterolemia (FH) is an inherited disorder of lipid metabolism, characterized by increased low density lipoprotein cholesterol (LDLc) levels. The main purpose of the current work was to explore alternative classification methods to traditional clinical criteria for FH diagnosis, based on several biochemical and biological indicators. Logistic regression (LR), decision tree (DT), random forest (RF) and naive Bayes (NB) algorithms were developed for this purpose, and thresholds were optimized by maximization of Youden index (YI). All models presented similar accuracy (Acc), specificity (Spec) and positive predictive values (PPV). Sensitivity (Sens) and G-mean values were significantly higher in LR and RF models, compared to the DT. When compared to Simon Broome (SB) biochemical criteria for FH diagnosis, all models presented significantly higher Acc, Spec and G-mean values (p < 0.01), and lower negative predictive value (NPV, p < 0.05). Moreover, LR and RF models presented comparable Sens values. Adjustment of the cut-off point by maximizing YI significantly increased Sens values, with no significant loss in Acc. The obtained results suggest such classification algorithms can be a viable alternative to be used as a widespread screening method. An online application has been developed to assess the performance of the LR model in a wider population.

Lipoprotein(a) Levels at Birth and in Early Childhood: The COMPARE Study

BACKGROUND AND OBJECTIVE

High lipoprotein(a) is a genetically determined causal risk factor for cardiovascular disease, and 20% of the adult population has high levels (ie, >42 mg/dL, >88 nmol/L). We investigated whether early life lipoprotein(a) levels measured in cord blood may serve as a proxy for neonatal venous blood levels, whether lipoprotein(a) birth levels (ie, cord or venous) predict levels later in life, and whether early life and parental levels correlate.

METHODS

The Compare study is a prospective cohort study of newborns (N = 450) from Copenhagen, Denmark, including blood sampling of parents. Plasma lipoprotein(a) was measured in cord blood (N = 402), neonatal venous blood (N = 356), and at 2 (N = 320) and 15 months follow-up (N = 148) of infants, and in parents (N = 705).

RESULTS

Mean lipoprotein(a) levels were 2.2 (95% CI, 1.9-2.5), 2.4 (2.0-2.7), 4.1 (3.4-4.9), and 14.6 (11.4-17.9) mg/dL in cord, neonatal venous, and 2- and 15-month venous samples, respectively. Lipoprotein(a) levels in cord blood correlated strongly with neonatal venous blood levels (R2 = 0.95, P < 0.001) and neonatal levels correlated moderately with 2- and 15-month levels (R2 = 0.68 and 0.67, both P < 0.001). Birth levels ≥ 90th percentile predicted lipoprotein(a) > 42 mg/dL at 15 months with positive predictive values of 89% and 85% for neonatal venous and cord blood. Neonatal and infant levels correlated weakly with parental levels, most pronounced at 15 months (R2 = 0.22, P < 0.001).

CONCLUSIONS

Lipoprotein(a) levels are low in early life, cord blood may serve as a proxy for neonatal venous blood, and birth levels ≥ 90th percentile can identify newborns at risk of developing high levels.

Effects of Alirocumab on Triglyceride Metabolism: A Fat-Tolerance Test and Nuclear Magnetic Resonance Spectroscopy Study

Background: PCSK9 antibodies strongly reduce LDL cholesterol. The effects of PCSK9 antibodies on triglyceride metabolism are less pronounced. The present study aimed to investigate in detail the effects of alirocumab on triglycerides, triglyceride-rich lipoproteins, and lipase regulators. Methods: A total of 24 patients with an indication for treatment with PCSK9 antibodies were recruited. There were two visits at the study site: the first before initiation of treatment with alirocumab and the second after 10 weeks of treatment. Fat-tolerance tests, nuclear magnetic resonance spectroscopy, and enzyme-linked immunosorbent assays were performed to analyze lipid metabolism. Results: A total of 21 participants underwent the first and second investigation. Among these, two participants only received alirocumab twice and 19 patients completed the trial per protocol. All of them had atherosclerotic vascular disease. There was no significant effect of alirocumab treatment on fasting triglycerides, post-prandial triglycerides, or lipoprotein-lipase regulating proteins. Total, large, and small LDL particle concentrations decreased, while the HDL particle concentration increased (all p < 0.001). Mean total circulating PCSK9 markedly increased in response to alirocumab treatment (p < 0.001). Whereas PCSK9 increased more than three-fold in all 19 compliant patients, it remained unchanged in those two patients with two injections only. Conclusion: Significant effects of alirocumab on triglyceride metabolism were not detectable in the ALIROCKS trial. The total circulating PCSK9 concentration might be a useful biomarker to differentiate non-adherence from non-response to PCSK9 antibodies.

Baseline Low-Density-Lipoprotein Cholesterol Modifies the Risk of All-Cause Death Associated With Elevated Lipoprotein(a) in Coronary Artery Disease Patients

Background: The prognostic value of elevated lipoprotein(a) [Lp(a)] in coronary artery disease (CAD) patients is inconsistent in previous studies, and whether such value changes at different low-density-lipoprotein cholesterol (LDL-C) levels is unclear. Methods and Findings: CAD patients treated with statin therapy from January 2007 to December 2018 in the Guangdong Provincial People's Hospital (NCT04407936) were consecutively enrolled. Individuals were categorized according to the baseline LDL-C at cut-off of 70 and 100 mg/dL. The primary outcome was 5-year all-cause death. Multivariate Cox proportional models and penalized spline analyses were used to evaluate the association between Lp(a) and all-cause mortality. Among 30,908 patients, the mean age was 63.1 ± 10.7 years, and 76.7% were men. A total of 2,383 (7.7%) patients died at 5-year follow-up. Compared with Lp(a) <50 mg/dL, Lp(a) ≥ 50 mg/dL predicted higher all-cause mortality (multivariable adjusted HR = 1.19, 95% CI 1.07-1.31) in the total cohort. However, when analyzed within each LDL-C category, there was no significant association between Lp(a) ≥ 50 mg/dL and higher all-cause mortality unless the baseline LDL-C was ≥ 100 mg/dL (HR = 1.19, 95% CI 1.04-1.36). The results from penalized spline analyses were robust. Conclusions: In statin-treated CAD patients, elevated Lp(a) was associated with increased risks of all-cause death, and such an association was modified by the baseline LDL-C levels. Patients with Lp(a) ≥ 50 mg/dL had higher long-term risks of all-cause death compared with those with Lp(a) <50 mg/dL only when their baseline LDL-C was ≥ 100 mg/dL.

ALDH2, ADCY3 and BCMO1 polymorphisms and lifestyle-induced traits are jointly associated with CAD risk in Chinese Han people

BACKGROUNDS

To investigate associations of genetic and environmental factors with coronary artery disease (CAD), we collected medical reports, lifestyle details, and blood samples of 2113 individuals, and then used the polymerase chain reaction (PCR)-ligase detection reaction (LDR) to genotype the targeted 102 SNPs.

METHODS

We adopted elastic net algorithm to build an association model that considered simultaneously genetic and lifestyle/clinical factors associated with CAD in Chinese Han population.

RESULTS

In this study, we developed an all covariates-based model to explain the risk of CAD, which incorporated 8 lifestyle/clinical factors and a gene-score variable calculated from 3 significant SNPs (rs671, rs6751537 and rs11641677), attaining an area under the curve (AUC) value of 0.71. It was found that, in terms of genetic variants, the AA genotype of rs671 in the additive (adjusted odds ratio (OR) = 2.51, p = 0.008) and recessive (adjusted OR = 2.12, p = 0.021) models, the GG genotype of rs6751537 in the additive (adjusted OR = 3.36, p = 0.001) and recessive (adjusted OR = 3.47, p = 0.001) models were associated with increased risk of CAD, while GG genotype of rs11641677 in additive model (adjusted OR = 0.39, p = 0.044) was associated with decreased risk of CAD. In terms of lifestyle/clinical factors, the history of hypertension (unadjusted OR = 2.37, p < 0.001) and dyslipidemia (unadjusted OR = 1.82, p = 0.007), age (unadjusted OR = 1.07, p < 0.001) and waist circumference (unadjusted OR = 1.02, p = 0.05) would significantly increase the risk of CAD, while height (unadjusted OR = 0.97, p = 0.006) and regular intake of chicken (unadjusted OR = 0.78, p = 0.008) reduced the risk of CAD. A significantinteraction was foundbetween rs671 and dyslipidemia (the relative excess risk due to interaction (RERI) = 3.36, p = 0.05).

CONCLUSION

In this study, we constructed an association model and identified a set of SNPs and lifestyle/clinical risk factors of CAD in Chinese Han population. By considering both genetic and non-genetic risk factors, the built model may provide implications for CAD pathogenesis and clues for screening tool development in Chinese Han population.

Primary Antiphospholipid Syndrome with and Without Acute Myocardial Infarction/Angina: A Cross-Sectional Study

Introduction

Acute myocardial infarct/angina (AMI-A) is a possible complication in primary antiphospholipid syndrome (pAPS) patients. This study compares data obtained from pAPS patients with and without AMI-A.

Methods

This cross-sectional study of 66 (85.2% female) pAPS patients (Sidney criteria). Demographics, clinical data, medication use, and antiphospholipid antibodies were evaluated. Patients were divided into two groups: pAPS with AMI-A and pAPS without AMI-A.

Results

Sixty-six patients with primary APS (six with AMI-A and 60 without AMI-A) were selected. They were similar for demographics, disease duration, and anthropometrics (p > 0.05). Patients with AMI-A compared to those patients without AMI-A had more frequently dyslipidemia (66 vs. 28%, p = 0.05), systemic hypertension (83 vs. 37%, p = 0.02), and increased levels of lipoprotein (a) (116 ± 67 vs. 36 ± 35 mg/dl, p = 0.0002). Interesting, current physical activity (66.7 vs. 23%, p = 0.04) was more seen in the first group when compared to the second one. Patients with AMI-A used more statins (66 vs. 22%, p = 0.017) and acetylsalicylic (100 vs. 28%, p = 0.05). Higher median levels of IgM anticardiolipin antibodies [70 (0–120) vs. 9 (0–120), p = 0.03] were observed in the first group.

Conclusions

pAPS patients and AMI-A have distinct clinical and laboratory spectra from those without AMI-A. It is characterized by dyslipidemia and hypertension, hyper lipoprotein(a), and a lower IgM anticardiolipin frequency.

Lipoprotein(a) and SARS-CoV-2 infections: Susceptibility to infections, ischemic heart disease and thromboembolic events

BACKGROUND

Comorbidities including ischemic heart disease (IHD) worsen outcomes after SARS-CoV-2 infections. High lipoprotein(a) [Lp(a)] concentrations are a strong risk factor for IHD and possibly for thromboembolic events. We therefore evaluated whether SARS-CoV-2 infections modify the risk of high Lp(a) concentrations for IHD or thromboembolic events during the first 8.5 months follow-up of the pandemic.

METHOD

Cohort study using data from the UK Biobank during the SARS-CoV-2 pandemic. Baseline Lp(a) was compared between SARS-CoV-2 positive patients and the population controls.

RESULTS

SARS-CoV-2 positive patients had Lp(a) concentrations similar to the population controls. The risk for IHD increased with higher Lp(a) concentrations in both, the population controls (n = 435,104) and SARS-CoV-2 positive patients (n = 6937). The causality of the findings was supported by a genetic risk score for Lp(a). A SARS-CoV-2 infection modified the association with a steeper increase in risk for infected patients (interaction p-value = 0.03). Although SARS-CoV-2 positive patients had a five-times higher frequency of thromboembolic events compared to the population controls (1.53% vs. 0.31%), the risk was not influenced by Lp(a).

CONCLUSIONS

SARS-CoV-2 infections enforce the association between high Lp(a) and IHD but the risk for thromboembolic events is not influenced by Lp(a).

Elevated lipoprotein(a) and lipoprotein-associated phospholipase A2 are associated with unfavorable functional outcomes in patients with ischemic stroke

Background

The association of lipoprotein(a) [Lp(a)] and stroke functional outcomes was conflicting. The aim of the study was to clarify whether high Lp(a) is associated with unfavorable functional outcomes in patients with ischemic stroke.

Methods

A total of 9709 individuals from the third China National Stroke Registry cohort were recruited. Plasma level of Lp(a) at admission was measured with enzyme-linked immunosorbent assay. The cut-off was set at the median for Lp(a). Functional outcome was assessed using the modified Rankin scale (mRS) at 3 months and 1 year after ischemic stroke. The association between Lp(a) and functional outcomes was evaluated using a logistic regression model.

Results

The median age was 63.0 years, and 31.1% participants were women. Patients in higher Lp(a) group had higher incidences of unfavorable functional outcomes at 3 months. In logistic regression model, elevated Lp(a) levels were associated with unfavorable functional outcomes at 3 months (Q4 vs. Q1: odds ratio 1.33, 95% confidence interval 1.11–1.61). Subgroup analysis showed that in the lower Lp-PLA₂ group, Lp(a) level was not associated with functional outcomes, but in the higher Lp-PLA₂ group, Lp(a) level was significantly associated with functional outcomes. After grouped by different levels of Lp(a) and Lp-PLA₂, the Lp(a) high/ Lp-PLA₂ high group showed the highest incidence of unfavorable functional outcomes at 3 months and 1 year.

Conclusions

Elevated Lp(a) level is associated with unfavorable functional outcomes in patients with ischemic stroke. The increment in both Lp(a) and Lp-PLA₂ are associated with unfavorable functional outcomes at 3 months and 1 year after ischemic stroke.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02359-w.

Lipoprotein(a) is associated with coronary atheroma progression: analysis from a serial coronary computed tomography angiography study

BACKGROUND

Lipoprotein(a) [Lp(a)] has been closely related to coronary atherosclerosis and might affect perivascular inflammation due to its proinflammatory properties. However, there are limited data about Lp(a) and related perivascular inflammation on coronary atheroma progression. Therefore, this study aimed to investigate the associations between Lp(a) and the perivascular fat attenuation index (FAI) with coronary atheroma progression detected by coronary computed tomography angiography (CCTA).

METHODS

Patients who underwent serial CCTA examinations without a history of revascularization and with available data for Lp(a) within one month before or after baseline and follow-up CCTA imaging scans were considered to be included. CCTA quantitative analyses were performed to obtain the total plaque volume (TPV) and the perivascular FAI. Coronary plaque progression (PP) was defined as a ≥ 10% increase in the change of the TPV at the patient level or the presence of new-onset coronary atheroma lesions. The associations between Lp(a) or the perivascular FAI with PP were examined by multivariate logistic regression.

RESULTS

A total of 116 patients were ultimately enrolled in the present study with a mean CCTA interscan interval of 30.80 ± 13.50 months. Among the 116 patients (mean age: 53.49 ± 10.21 years, males: 83.6%), 32 patients presented PP during the follow-up interval. Lp(a) levels were significantly higher among PP patients than those among non-PP patients at both baseline [15.80 (9.09-33.60) mg/dLvs. 10.50 (4.75-19.71) mg/dL,P = 0.029] and follow-up [20.60 (10.45-34.55) mg/dLvs. 8.77 (5.00-18.78) mg/dL,P = 0.004]. However, there were no differences in the perivascular FAI between PP group and non-PP group at either baseline or follow-up. Multivariate logistic regression analysis showed that elevated baseline Lp(a) level (OR = 1.031, 95% CI: 1.005-1.058,P = 0.019) was an independent risk factor for PP after adjustment for other conventional variables.

CONCLUSIONS

Lp(a) was independently associated with coronary atheroma progression beyond low-density lipoprotein cholesterol and other conventional risk factors. Further studies are warranted to identify the inflammation effect exhibited as the perivascular FAI on coronary atheroma progression.

Lipoprotein (a) and Hypertension

PURPOSE OF REVIEW

To provide an overview of the associations between elevated blood pressure and lipoprotein (a) and possible causal links, as well as data on the prevalence of elevated lipoprotein (a) in a cohort of hypertensive patients.

RECENT FINDINGS

Elevated lipoprotein (a) is now considered to be an independent and causal risk factor for atherosclerotic cardiovascular disease and calcific aortic valve disease. Despite this, there are limited data demonstrating an association between elevated lipoprotein (a) and hypertension. Further, there is limited mechanistic data linking lipoprotein (a) and hypertension through either renal impairment or direct effects on the vasculature. Despite the links between lipoprotein (a) and atherosclerosis, there are limited data demonstrating an association with hypertension. Evidence from our clinic suggests that ~ 30% of the patients in this at-risk, hypertensive cohort had elevated lipoprotein (a) levels and that measurement of lipoprotein (a) maybe useful in risk stratification.

Elevated lipoprotein(a) in mitral and aortic valve calcification and disease: The Copenhagen General Population Study

BACKGROUND AND AIMS

We tested the hypotheses (i) that elevated lipoprotein(a) is causally associated with both mitral and aortic valve calcification and disease, and (ii) that aortic valve calcification mediates the effect of elevated lipoprotein(a) on aortic valve stenosis.

METHODS

From the Copenhagen General Population study, we included 12,006 individuals who underwent cardiac computed tomography to measure mitral and aortic valve calcification and 85,884 to examine risk of heart valve disease. Participants had information on plasma lipoprotein(a) and genetic instruments associated with plasma lipoprotein(a) to investigate potential causality.

RESULTS

At age 70-79 years, 29% and 54% had mitral and aortic valve calcification, respectively. For 10-fold higher lipoprotein(a) levels, multifactorially adjusted odds ratios for mitral and aortic valve calcification were 1.26 (95% confidence interval: 1.13-1.41) and 1.62 (1.48-1.77). For mitral and aortic valve stenosis, corresponding hazard ratios were 0.93 (95%CI:0.40-2.15, 19 events) and 1.54 (1.38-1.71, 1158 events), respectively. For ≤23 versus ≥36 kringle IV type 2 number of repeats, the age and sex adjusted odds ratios for mitral and aortic valve calcification were 1.53 (1.18-1.99) and 2.23 (1.81-2.76). For carriers versus non-carriers of LPA rs10455872, odds ratios for mitral and aortic valve calcification were 1.33 (1.13-1.57) and 1.86 (1.64-2.13). For aortic valve stenosis, 31% (95%CI:16%-76%) of the effect of lipoprotein(a) was mediated through calcification.

CONCLUSIONS

Elevated lipoprotein(a) was genetically and observationally associated with mitral and aortic valve calcification and aortic valve stenosis. Aortic valve calcification mediated 31% of the effect of elevated lipoprotein(a) on aortic valve stenosis.

Lipoprotein(a): Pathophysiology, measurement, indication and treatment in cardiovascular disease. A consensus statement from the Nouvelle Société Francophone d'Athérosclérose (NSFA)

Lipoprotein(a) is an apolipoprotein B100-containing low-density lipoprotein-like particle that is rich in cholesterol, and is associated with a second major protein, apolipoprotein(a). Apolipoprotein(a) possesses structural similarity to plasminogen but lacks fibrinolytic activity. As a consequence of its composite structure, lipoprotein(a) may: (1) elicit a prothrombotic/antifibrinolytic action favouring clot stability; and (2) enhance atherosclerosis progression via its propensity for retention in the arterial intima, with deposition of its cholesterol load at sites of plaque formation. Equally, lipoprotein(a) may induce inflammation and calcification in the aortic leaflet valve interstitium, leading to calcific aortic valve stenosis. Experimental, epidemiological and genetic evidence support the contention that elevated concentrations of lipoprotein(a) are causally related to atherothrombotic risk and equally to calcific aortic valve stenosis. The plasma concentration of lipoprotein(a) is principally determined by genetic factors, is not influenced by dietary habits, remains essentially constant over the lifetime of a given individual and is the most powerful variable for prediction of lipoprotein(a)-associated cardiovascular risk. However, major interindividual variations (up to 1000-fold) are characteristic of lipoprotein(a) concentrations. In this context, lipoprotein(a) assays, although currently insufficiently standardized, are of considerable interest, not only in stratifying cardiovascular risk, but equally in the clinical follow-up of patients treated with novel lipid-lowering therapies targeted at lipoprotein(a) (e.g. antiapolipoprotein(a) antisense oligonucleotides and small interfering ribonucleic acids) that markedly reduce circulating lipoprotein(a) concentrations. We recommend that lipoprotein(a) be measured once in subjects at high cardiovascular risk with premature coronary heart disease, in familial hypercholesterolaemia, in those with a family history of coronary heart disease and in those with recurrent coronary heart disease despite lipid-lowering treatment. Because of its clinical relevance, the cost of lipoprotein(a) testing should be covered by social security and health authorities.

Statin therapy and lipoprotein(a) levels: a systematic review and meta-analysis

AIMS 

Lipoprotein(a) [Lp(a)] is a causal and independent risk factor for cardiovascular disease (CVD). People with elevated Lp(a) are often prescribed statins as they also often show elevated low-density lipoprotein cholesterol (LDL-C) levels. While statins are well-established in lowering LDL-C, their effect on Lp(a) remains unclear. We evaluated the effect of statins compared to placebo on Lp(a) and the effects of different types and intensities of statin therapy on Lp(a).

METHODS AND RESULTS 

We conducted a systematic review and meta-analysis of randomized trials with a statin and placebo arm. Medline and EMBASE were searched until August 2019. Quality assessment of studies was done using Cochrane risk-of-bias tool (RoB 2). Mean difference of absolute and percentage changes of Lp(a) in the statin vs. the placebo arms were pooled using a random-effects meta-analysis. We compared effects of different types and intensities of statin therapy using subgroup- and network meta-analyses. Certainty of the evidence was determined using GRADE (Grading of Recommendations, Assessment, Development, and Evaluation). Overall, 39 studies (24 448 participants) were included. Mean differences (95% confidence interval) of absolute and percentage changes in the statin vs. the placebo arms were 1.1 mg/dL (0.5-1.6, P < 0.0001) and 0.1% (-3.6% to 4.0%, P = 0.95), respectively (moderate-certainty evidence). None of the types of statins changed Lp(a) significantly compared to placebo (very low- to high-certainty evidence), as well as intensities of statin therapy (low- to moderate-certainty evidence).

CONCLUSION 

Statin therapy does not lead to clinically important differences in Lp(a) compared to placebo in patients at risk for CVD. Our findings suggest that in these patients, statin therapy will not change Lp(a)-associated CVD risk.

Unravelling lipoprotein metabolism with stable isotopes: tracing the flow

Dysregulated lipoprotein metabolism is a major cause of atherosclerotic cardiovascular disease (ASCVD). Use of stable isotope tracers and compartmental modelling have provided deeper understanding of the mechanisms underlying lipid disorders in patients at high risk of ASCVD, including familial hypercholesterolemia (FH), elevated lipoprotein(a) [Lp(a)] and metabolic syndrome (MetS). In patients with FH, deficiency in low-density lipoprotein (LDL) receptor activity not only impairs the catabolism of LDL, but also induces hepatic overproduction and decreases catabolism of triglyceride-rich lipoproteins (TRLs). Patients with elevated Lp(a) are characterized by increased hepatic secretion of Lp(a) particles. Atherogenic dyslipidemia in MetS patients relates to a combination of overproduction of very-low density lipoprotein-apolipoprotein (apo) B-100, decreased catabolism of apoB-100-containing particles, and increased catabolism of high-density lipoprotein-apoA-I particles, as well as to impaired clearance of TRLs in the postprandial state. Kinetic studies show that weight loss, fish oils, statins and fibrates have complementary modes of action that correct atherogenic dyslipidemia. Defining the kinetic mechanisms of action of proprotein convertase subtilisin/kexin type 9 and angiopoietin-like 3 inhibitors on lipid and lipoprotein mechanism in dyslipidemic subjects will further our understanding of these therapies in decreasing the development of ASCVD. "Everything changes but change itself. Everything flows and nothing remains the same... You cannot step twice into the same river, for other waters and yet others go flowing ever on." Heraclitus (c.535- c. 475 BCE).

Lipoprotein (a) and Cardiovascular Disease: A Missing Link for Premature Atherosclerotic Heart Disease and/or Residual Risk

ABSTRACT

Lipoprotein(a) or lipoprotein "little a" is an under-recognized causal risk factor for cardiovascular (CV) disease (CVD), including coronary atherosclerosis, aortic valvular stenosis, ischemic stroke, heart failure and peripheral arterial disease. Elevated plasma Lp(a) (≥50 mg/dL or ≥100 nmol/L) is commonly encountered in almost 1 in 5 individuals and confers a higher CV risk compared to those with normal Lp(a) levels, although such normal levels have not been generally agreed upon. Elevated Lp(a) is considered a cause of premature and accelerated atherosclerotic CVD. Thus, in patients with a positive family or personal history of premature coronary artery disease (CAD), Lp(a) should be measured. However, elevated Lp(a) may confer increased risk for incident CAD even in the absence of a family history of CAD, and even in those who have guideline-lowered LDL-cholesterol (<70 mg/dl) and continue to have a persisting CV residual risk. Thus, measurement of Lp(a) will have a significant clinical impact on the assessment of atherosclerotic CVD risk, and will assume a more important role in managing patients with CVD with the advent and clinical application of specific Lp(a)-lowering therapies. Conventional therapeutic approaches like lifestyle modification and statin therapy remain ineffective at lowering Lp(a). Newer treatment modalities, such as gene silencing via RNA interference with use of antisense oligonucleotide(s) or small interfering RNA molecules targeting Lp(a) seem very promising. These issues are herein reviewed, accumulated data are scrutinized, meta-analyses and current guidelines are tabulated and Lp(a)-related CVDs and newer therapeutic modalities are pictorially illustrated.

Lipoprotein(a) and subclinical coronary atherosclerosis in asymptomatic individuals

BACKGROUND AND AIMS

There are limited data regarding the association between lipoprotein(a) (Lp[a]) and subclinical coronary atherosclerosis. This study investigated the association between Lp(a) and subclinical coronary atherosclerosis detected by coronary computed tomographic angiography (CCTA) in an asymptomatic population.

METHODS

We retrospectively analyzed 7201 asymptomatic individuals (mean age 54.4 ± 7.9 years; 65.3% men with no prior history of coronary artery disease who voluntarily underwent CCTA as part of a general health examination). The degree and extent of subclinical coronary atherosclerosis were evaluated by CCTA. Study participants were stratified into quartiles according to their Lp(a) levels (<4.3, 4.3-8.9, 9.0-20.1, and ≥20.2 mg/dL).

RESULTS

Of the study participants, any coronary plaque on CCTA was observed in 2557 (35.5%). Specifically, calcified, non-calcified, and mixed plaques were observed in 2411 (33.5%), 363 (5.0%) and 249 (3.5%) participants, respectively. After adjustment for the presence of cardiovascular risk factors, the fourth Lp(a) quartile was significantly associated with any coronary (odds ratio [OR] 1.212; 95% confidence interval [CI] 1.038-1.416), calcified (1.205, 95% CI 1.030-1.410), non-calcified (1.588, 95% CI 1.152-2.189), or mixed (1.674, 95% CI 1.172-2.391) plaque compared with the first Lp(a) quartile. In addition, 442 (6.1%) had significant coronary artery stenosis (≥50% diameter stenosis). The odds ratio for significant stenosis (1.537, 95% CI 1.153-2.048) was higher in the fourth quartile compared with the first quartile.

CONCLUSIONS

In this large cross-sectional study with asymptomatic individuals undergoing CCTA, higher Lp(a) level was associated with subclinical coronary atherosclerosis.

Elevated Lipoprotein(a): Background, Current Insights and Future Potential Therapies

Lipoprotein(a) forms a subfraction of the lipid profile and is characterized by the addition of apolipprotein(a) (apo(a)) to apoB100 derived particles. Its levels are mostly genetically determined inversely related to the number of protein domain (kringle) repeats in apo(a). In epidemiological studies, it shows consistent association with cardiovascular disease (CVD) and most recently with extent of aortic stenosis. Issues with standardizing the measurement of Lp(a) are being resolved and consensus statements favor its measurement in patients at high risk of, or with family histories of CVD events. Major lipid-lowering therapies such as statin, fibrates, and ezetimibe have little effect on Lp(a) levels. Therapies such as niacin or cholesterol ester transfer protein (CETP) inhibitors lower Lp(a) as well as reducing other lipid-related risk factors but have failed to clearly reduce CVD events. Proprotein convertase subtilisin kexin-9 (PCSK9) inhibitors reduce cholesterol and Lp(a) as well as reducing CVD events. New antisense therapies specifically targeting apo(a) and hence Lp(a) have greater and more specific effects and will help clarify the extent to which intervention in Lp(a) levels will reduce CVD events.

Very low lipoprotein(a) and increased mortality risk after myocardial infarction

BACKGROUND

Inconclusive data exist on risk associated with Lp(a) in patients after myocardial infarction (MI). Aims of the present study were to evaluate the association of Lp(a) level with total mortality and recurrent cardiovascular events.

DESIGN AND METHODS

Single center prospective registry of consecutive patients hospitalized for acute myocardial infarction between June 2017 and June 2020 at a large tertiary cardiac center with available blood samples drawn <24h of admission.

RESULTS

Data from 851 consecutive patients hospitalized for MI were evaluated. During the median follow-up of 19 months (interquartile range 10-27), 58 (6.8%) patients died. Nonlinear modelling revealed a U-shaped association between Lp(a) and total mortality risk. Compared to patients with Lp(a) ranging between 10-30 nmol/L and after multivariate adjustment, total mortality risk was increased both in patients with Lp(a)<7 nmol/L (hazard ratio (HR) 4.08, 95% confidence interval (CI) 1.72-9.68) and Lp(a) ≥125 nmol/L (HR 2.92, 95% CI 1.16-7.37), respectively. Similarly, the risk of combined endpoint of acute coronary syndrome recurrence or cardiovascular mortality was increased both in patients with low (sub-HR 2.60, 95% CI 1.33-5.08) and high (sub-HR 2.10, 95% CI 1.00-4.39) Lp(a). Adjustment for heart failure signs at the time of hospitalization weakened the association with total mortality and recurrent cardiovascular events.

CONCLUSIONS

In the present analysis, both high and low concentrations of Lp(a) were associated with an increased risk of total mortality and recurrent cardiovascular events after MI. The excess of mortality associated with Lp(a) was partially attributable to more prevalent heart failure.

Lipoprotein(a): Knowns, unknowns and uncertainties

Over the last 10 years, there have been advances on several aspects of lipoprotein(a) which are reviewed in the present article. Since the standard immunoassays for measuring lipoprotein(a) are not fully apo(a) isoform-insensitive, the application of an LC-MS/MS method for assaying molar concentrations of lipoprotein(a) has been advocated. Genome wide association, epidemiological, and clinical studies have established high lipoprotein(a) as a causal risk factor for atherosclerotic cardiovascular diseases (ASCVD). However, the relative importance of molar concentration, apo(a) isoform size or variants within the LPA gene is still controversial. Lipoprotein(a)-raising single nucleotide polymorphisms has not been shown to add on value in predicting ASCVD beyond lipoprotein(a) concentrations. Although hyperlipoproteinemia(a) represents an important confounder in the diagnosis of familial hypercholesterolemia (FH), it enhances the risk of ASCVD in these patients. Thus, identification of new cases of hyperlipoproteinemia(a) during cascade testing can increase the identification of high-risk individuals. However, it remains unclear whether FH itself increases lipoprotein(a). The ASCVD risk associated with lipoprotein(a) seems to follow a linear gradient across the distribution, regardless of racial subgroups and other risk factors. The inverse association with the risk of developing type 2 diabetes needs consideration as effective lipoprotein(a) lowering therapies are progressing towards the market. Considering that Mendelian randomization analyses have identified the degree of lipoprotein(a)-lowering that is required to achieve ASCVD benefit, the findings of the ongoing outcome trial with pelacarsen will clarify whether dramatically lowering lipoprotein(a) levels can reduce the risk of ASCVD.

Lipoprotein (a) as a treatment target for cardiovascular disease prevention and related therapeutic strategies: a critical overview

Advances in several fields of cardiovascular (CV) medicine have produced new treatments (e.g. to treat dyslipidaemia) that have proven efficacy in terms of reducing deaths and providing a better quality of life. However, the burden of CV disease (CVD) remains high. Thus, there is a need to search for new treatment targets. Lipoprotein (a) [Lp(a)] has emerged as a potential novel target since there is evidence that it contributes to CVD events. In this narrative review, we present the current evidence of the potential causal relationship between Lp(a) and CVD and discuss the likely magnitude of Lp(a) lowering required to produce a clinical benefit. We also consider current and investigational treatments targeting Lp(a), along with the potential cost of these interventions.

Lipids and Lipoproteins in Health and Disease: Focus on Targeting Atherosclerosis

Despite advances in pharmacotherapy, intervention devices and techniques, residual cardiovascular risks still cause a large burden on public health. Whilst most guidelines encourage achieving target levels of specific lipids and lipoproteins to reduce these risks, increasing evidence has shown that molecular modification of these lipoproteins also has a critical impact on their atherogenicity. Modification of low-density lipoprotein (LDL) by oxidation, glycation, peroxidation, apolipoprotein C-III adhesion, and the small dense subtype largely augment its atherogenicity. Post-translational modification by oxidation, carbamylation, glycation, and imbalance of molecular components can reduce the capacity of high-density lipoprotein (HDL) for reverse cholesterol transport. Elevated levels of triglycerides (TGs), apolipoprotein C-III and lipoprotein(a), and a decreased level of apolipoprotein A-I are closely associated with atherosclerotic cardiovascular disease. Pharmacotherapies aimed at reducing TGs, lipoprotein(a), and apolipoprotein C-III, and enhancing apolipoprotein A-1 are undergoing trials, and promising preliminary results have been reported. In this review, we aim to update the evidence on modifications of major lipid and lipoprotein components, including LDL, HDL, TG, apolipoprotein, and lipoprotein(a). We also discuss examples of translating findings from basic research to potential therapeutic targets for drug development.

Plasma lipoprotein(a) measured in the routine clinical care is associated to atherosclerotic cardiovascular disease during a 14-year follow-up

AIMS

To investigate plasma lipoprotein(a) [Lp(a)] levels measured in routine clinical care and their association with mortality and cardiovascular disease.

METHODS AND RESULTS

This retrospective registry-based observational cohort study includes all individuals with plasma Lp(a) results measured at the Karolinska University Laboratory 2003-17. Outcome data were captured in national outcome registries. Levels of Lp(a) expressed in mass or molar units were examined separately. In adjusted Cox regression models, association between deciles of plasma Lp(a) concentrations, mortality, and cardiovascular outcomes were assessed. A total of 23 398 individuals [52% females, mean (standard deviation) age 55.5 (17.2) years, median Lp(a) levels 17 mg/dL or 19.5 nmol/L] were included. Individuals with an Lp(a) level >90th decile (>90 mg/dL or >180 nmol/L) had hazard ratios (95% confidence interval) of 1.25 (1.05-1.50) for major adverse cardiovascular events (P = 0.013), 1.37 (1.14-1.64) for atherosclerotic cardiovascular disease (P = 0.001), and 1.62 (1.28-2.05) for coronary artery disease (P ≤ 0.001), compared to individuals with Lp(a) ≤50th decile. No association between Lp(a) and mortality, peripheral artery disease, or ischaemic stroke was observed.

CONCLUSION

High Lp(a) levels are associated with adverse cardiovascular disease outcomes also in individuals with Lp(a) measured in routine clinical care. This supports the 2019 ESC/EAS recommendation to measure Lp(a) at least once during lifetime to assess cardiovascular risk and implies the need for intensive preventive therapy in patients with elevated Lp(a).

Lipoprotein(a) Where Do We Stand? From the Physiopathology to Innovative Terapy

A number of epidemiologic studies have demonstrated a strong association between increasing lipoprotein a [Lp(a)] and cardiovascular disease. This correlation was demonstrated independent of other known cardiovascular (CV) risk factors. Screening for Lp(a) in the general population is not recommended, although Lp(a) levels are predominantly genetically determined so a single assessment is needed to identify patients at risk. In 2019 ESC/EAS guidelines recommend Lp(a) measurement at least once a lifetime, fo subjects at very high and high CV risk and those with a family history of premature cardiovascular disease, to reclassify patients with borderline risk. As concerning medications, statins play a key role in lipid lowering therapy, but present poor efficacy on Lp(a) levels. Actually, treatment options for elevated serum levels of Lp(a) are very limited. Apheresis is the most effective and well tolerated treatment in patients with high levels of Lp(a). However, promising new therapies, in particular antisense oligonucleotides have showed to be able to significantly reduce Lp(a) in phase II RCT. This review provides an overview of the biology and epidemiology of Lp(a), with a view to future therapies.

Role of Increased Lipoprotein (a) in Retinal Vein Occlusion: A Systematic Review and Meta-analysis

Background  Increased lipoprotein (a) [Lp(a)] has been associated with enhanced risk of cardiovascular events and more recently with venous thromboembolism. However, there is inconclusive data on the association between enhanced Lp(a) and retinal vein occlusion (RVO). We aimed to assess the role of Lp(a) in RVO.

Methods  We performed a systematic review and meta-analysis of the studies addressing the role of Lp(a) in RVO. A systematic literature search was performed to identify all published papers reporting Lp(a) levels. Main outcome measures consisted of Lp(a) levels in patients with (cases) or without (controls) RVO.

Results  We included 13 studies for a total of 1,040 cases and 16,648 controls. Lp(a) levels above normal limits were associated with RVO (OR 2.38, 95% CI 1.7–3.34) and patients with RVO had higher Lp(a) levels than controls (weighted mean difference: 13.4 mg/dL, 95% CI 8.2–18.6).

Conclusion  Increased Lp(a) levels associate with RVO and should be included among diagnostic and prognostic indexes for this unusual-site vein thrombosis. Therapeutic interventions aimed to lower Lp(a) should be tested in RVO patients.

Lipoprotein(a) and Cardiovascular Disease

BACKGROUND

High lipoprotein(a) concentrations present in 10%-20% of the population have long been linked to increased risk of ischemic cardiovascular disease. It is unclear whether high concentrations represent an unmet medical need. Lipoprotein(a) is currently not a target for treatment to prevent cardiovascular disease.

CONTENT

The present review summarizes evidence of causality for high lipoprotein(a) concentrations gained from large genetic epidemiologic studies and discusses measurements of lipoprotein(a) and future treatment options for high values found in an estimated >1 billion individuals worldwide.

SUMMARY

Evidence from mechanistic, observational, and genetic studies support a causal role of lipoprotein(a) in the development of cardiovascular disease, including coronary heart disease and peripheral arterial disease, as well as aortic valve stenosis, and likely also ischemic stroke. Effect sizes are most pronounced for myocardial infarction, peripheral arterial disease, and aortic valve stenosis where high lipoprotein(a) concentrations predict 2- to 3-fold increases in risk. Lipoprotein(a) measurements should be performed using well-validated assays with traceability to a recognized calibrator to ensure common cut-offs for high concentrations and risk assessment. Randomized cardiovascular outcome trials are needed to provide final evidence of causality and to assess the potential clinical benefit of novel, potent lipoprotein(a) lowering therapies.

Lipoprotein(a)

Lipoprotein(a) [Lp(a)] is an atherogenic lipoprotein with a strong genetic regulation. Up to 90% of the concentrations are explained by a single gene, the LPA gene. The concentrations show a several-hundred-fold interindividual variability ranging from less than 0.1 mg/dL to more than 300 mg/dL. Lp(a) plasma concentrations above 30 mg/dL and even more above 50 mg/dL are associated with an increased risk for cardiovascular disease including myocardial infarction, stroke, aortic valve stenosis, heart failure, peripheral arterial disease, and all-cause mortality. Since concentrations above 50 mg/dL are observed in roughly 20% of the Caucasian population and in an even higher frequency in African-American and Asian-Indian ethnicities, it can be assumed that Lp(a) is one of the most important genetically determined risk factors for cardiovascular disease.Carriers of genetic variants that are associated with high Lp(a) concentrations have a markedly increased risk for cardiovascular events. Studies that used these genetic variants as a genetic instrument to support a causal role for Lp(a) as a cardiovascular risk factor are called Mendelian randomization studies. The principle of this type of studies has been introduced and tested for the first time ever with Lp(a) and its genetic determinants.There are currently no approved pharmacologic therapies that specifically target Lp(a) concentrations. However, some therapies that target primarily LDL cholesterol have also an influence on Lp(a) concentrations. These are mainly PCSK9 inhibitors that lower LDL cholesterol by 60% and Lp(a) by 25-30%. Furthermore, lipoprotein apheresis lowers both, Lp(a) and LDL cholesterol, by about 60-70%. Some sophisticated study designs and statistical analyses provided support that lowering Lp(a) by these therapies also lowers cardiovascular events on top of the effect caused by lowering LDL cholesterol, although this was not the main target of the therapy. Currently, new therapies targeting RNA such as antisense oligonucleotides (ASO) or small interfering RNA (siRNA) against apolipoprotein(a), the main protein of the Lp(a) particle, are under examination and lower Lp(a) concentrations up to 90%. Since these therapies specifically lower Lp(a) concentrations without influencing other lipoproteins, they will serve the last piece of the puzzle whether a decrease of Lp(a) results also in a decrease of cardiovascular events.

Association of lipoprotein(a) with intrinsic and on-clopidogrel platelet reactivity

Lipoprotein(a) [Lp(a)] is an independent, genetically determined, and causal risk factor for cardiovascular disease. Laboratory data have suggested an interaction of Lp(a) with platelet function, potentially caused by its interaction with platelet receptors. So far, the potential association of Lp(a) with platelet activation and reactivity has not been proven in larger clinical cohorts. This study analyzed intrinsic platelet reactivity before loading with clopidogrel 600 mg and on-treatment platelet reactivity tested 24 h following loading in patients undergoing elective coronary angiography. Platelet reactivity was tested by optical aggregometry following stimulation with collagen or adenosine diphosphate as well as by flow cytometry. Lp(a) levels were directly measured in all patients from fresh samples. The present analysis included 1912 patients. Lp(a) levels ranged between 0 and 332 mg/dl. There was a significant association of rising levels of Lp(a) with a higher prevalence of a history of ischemic heart disease (p < 0.001) and more extensive coronary artery disease (p = 0.001). Results for intrinsic (p = 0.80) and on-clopidogrel platelet reactivity (p = 0.81) did not differ between quartiles of Lp(a) levels. Flow cytometry analyses of expression of different platelet surface proteins (CD41, CD62P or PAC-1) confirmed these findings. Correlation analyses of levels of Lp(a) with any of the tested platelet activation markers did not show any correlation. The present data do not support the hypothesis of an interaction of Lp(a) with platelet reactivity.

The Role of Antisense Therapies Targeting Lipoprotein(a)

ABSTRACT

Atherosclerotic cardiovascular disease (ASCVD) continues to be the leading cause of preventable death in the United States. Elevated low-density lipoprotein cholesterol (LDL-C) is well known to result in cardiovascular disease. Mainstay therapy for reducing LDL-C and ASCVD risk is statin therapy. Despite achieving desired LDL-C levels with lipid-lowering therapy, cardiovascular residual risk often persists. Elevated lipoprotein(a) [Lp(a)] levels have been highlighted as an inherent independent predictor of ASCVD, and decreasing Lp(a) levels may result in a significant reduction in the residual risk in high-risk patients. To date, there are no approved medications to lower Lp(a) levels. Nicotinic acid, proprotein convertase subtilisin/kexin 9 inhibitors, and antisense oligonucleotide have demonstrated modest to potent Lp(a) reduction. Spotlight has been placed on antisense oligonucleotides and their role in Lp(a) lowering. APO(a)LRx is in the frontline for selectively decreasing Lp(a) concentrations and ongoing research may prove that this medication may lower Lp(a)-mediated residual risk, translating into cardiovascular benefit.

Lipoprotein(a) is associated with large artery atherosclerosis stroke aetiology and stroke recurrence among patients below the age of 60 years: results from the BIOSIGNAL study

AIMS

Lipoprotein(a) [Lp(a)] is a recognized causal risk factor for atherosclerotic cardiovascular disease but its role for acute ischaemic stroke (AIS) is controversial. In this study, we evaluated the association of Lp(a) with large artery atherosclerosis (LAA) stroke and risk of recurrent cerebrovascular events in AIS patients.

METHODS AND RESULTS

For this analysis of the prospective, observational, multicentre BIOSIGNAL cohort study we measured Lp(a) levels in plasma samples of 1733 primarily Caucasian (98.6%) AIS patients, collected within 24 h after symptom onset. Primary outcomes were LAA stroke aetiology and recurrent cerebrovascular events (ischaemic stroke or transient ischaemic attack) within 1 year. We showed that Lp(a) levels are independently associated with LAA stroke aetiology [adjusted odds ratio 1.48, 95% confidence interval (CI) 1.14-1.90, per unit log10Lp(a) increase] and identified age as a potent effect modifier (Pinteraction =0.031) of this association. The adjusted odds ratio for LAA stroke in patients aged <60 years was 3.64 (95% CI 1.76-7.52) per unit log10Lp(a) increase and 4.04 (95% CI 1.73-9.43) using the established cut-off ≥100 nmol/l. For 152 recurrent cerebrovascular events, we did not find a significant association in the whole cohort. However, Lp(a) levels ≥100 nmol/l were associated with an increased risk for recurrent events among patients who were either <60 years [adjusted hazard ratio (HR) 2.40, 95% CI 1.05-5.47], had evident LAA stroke aetiology (adjusted HR 2.18, 95% CI 1.08-4.40), or had no known atrial fibrillation (adjusted HR 1.60, 95% CI 1.03-2.48).

CONCLUSION

Elevated Lp(a) was independently associated with LAA stroke aetiology and risk of recurrent cerebrovascular events among primarily Caucasian individuals aged <60 years or with evident arteriosclerotic disease.

Lipoproteins in chronic kidney disease: from bench to bedside

Chronic kidney disease (CKD) is associated with high cardiovascular risk. CKD patients exhibit a specific lipoprotein pattern termed 'uraemic dyslipidaemia', which is characterized by rather normal low-density lipoprotein cholesterol, low high-density lipoprotein cholesterol, and high triglyceride plasma levels. All three lipoprotein classes are involved in the pathogenesis of CKD-associated cardiovascular diseases (CVDs). Uraemia leads to several modifications of the structure of lipoproteins such as changes of the proteome and the lipidome, post-translational protein modifications (e.g. carbamylation) and accumulation of small-molecular substances within the lipoprotein moieties, which affect their functionality. Lipoproteins from CKD patients interfere with lipid transport and promote inflammation, oxidative stress, endothelial dysfunction as well as other features of atherogenesis, thus contributing to the development of CKD-associated CVD. While, lipid-modifying therapies play an important role in the management of CKD patients, their efficacy is modulated by kidney function. Novel therapeutic agents to prevent the adverse remodelling of lipoproteins in CKD and to improve their functional properties are highly desirable and partially under development.

Genetics of Lipoprotein(a): Cardiovascular Disease and Future Therapy

PURPOSE OF REVIEW

Lipoprotein(a) levels are determined 80-90% by genetics and differ by up to 1000-fold between individuals. This review discusses the most recent literature on lipoprotein(a) as a risk factor for cardiovascular disease, as well as future lipoprotein(a)lowering therapies.

RECENT FINDINGS

Over the past few decades, numerous studies have observed that high lipoprotein(a) levels are associated observationally and causally through human genetics with increased risk of cardiovascular disease. Also, the development of safe and effective therapies to lower lipoprotein(a) is ongoing, most importantly using antisense oligonucleotides to prevent production of lipoprotein(a). Finally, both observational and genetic studies have estimated the extent to which lowering of lipoprotein(a) is needed to obtain a clinically meaningful reduction in the risk of cardiovascular disease. Lipoprotein(a) is a causal risk factor for cardiovascular disease; however, currently no approved safe and effective therapy is available to lower lipoprotein(a) levels. That said, promising randomized studies using antisense oligonucleotides show up to 80% reductions in lipoprotein(a), reductions that hopefully will result in lowering the risk of cardiovascular disease as presently tested in the ongoing HORIZON phase 3 trial.

Lipoprotein (a): Recent Updates on a Unique Lipoprotein

PURPOSE OF REVIEW

Genetic, epidemiological, and translational data indicate that Lipoprotein (a) [Lp(a)] is likely in the causal pathway for atherosclerotic cardiovascular diseases as well as calcification of the aortic valves.

RECENT FINDINGS

Lp(a) is structurally similar to low-density lipoprotein, but in addition to apolipoprotein B-100, it has a glycoprotein apolipoprotein(a) [apo(a)], which is attached to the apolipoprotein B-100. Several distinctive properties of Lp(a) can be attributed to the presence of apo(a). This review discusses the current state of literature on pathophysiological and clinical aspects of Lp(a). After five decades of research, the understanding of Lp(a) structure, biochemistry, and pathophysiology of its cardiovascular manifestations still remains less than fully understood. Universally, Lp(a) elevation may be the most predominant monogenetic lipid disorder with approximate prevalence of Lp(a)>50 mg/dL among estimated >1.4 billion people. This makes a compelling rationale for diagnosing and managing Lp(a)-mediated risk. In addition to discussing various cardiovascular phenotypes of Lp(a) and associated morbidity, we also outline current and emerging therapies aimed at identifying a definitive treatment for elevated Lp(a) levels.

Lipoprotein(a) levels and atherosclerotic plaque characteristics in the carotid artery: The Plaque at RISK (PARISK) study

BACKGROUND AND AIMS

Lipoprotein(a) is an independent risk factor for cardiovascular disease and recurrent ischemic stroke. Lipoprotein(a) levels are known to be associated with carotid artery stenosis, but the relation of lipoprotein(a) levels to carotid atherosclerotic plaque composition and morphology is less known. We hypothesize that higher lipoprotein(a) levels and lipoprotein(a)-related SNPs are associated with a more vulnerable carotid plaque and that this effect is sex-specific.

METHODS

In 182 patients of the Plaque At RISK study we determined lipoprotein(a) concentrations, apo(a) KIV-2 repeats and LPA SNPs. Imaging characteristics of carotid atherosclerosis were determined by MDCTA (n = 161) and/or MRI (n = 171). Regressions analyses were used to investigate sex-stratified associations between lipoprotein(a) levels, apo(a) KIV-2 repeats, and LPA SNPs and imaging characteristics.

RESULTS

Lipoprotein(a) was associated with presence of lipid-rich necrotic core (LRNC) (aOR = 1.07, 95% CI: 1.00; 1.15), thin-or-ruptured fibrous cap (TRFC) (aOR = 1.07, 95% CI: 1.01; 1.14), and degree of stenosis (β = 0.44, 95% CI: 0.00; 0.88). In women, lipoprotein(a) was associated with presence of intraplaque hemorrhage (IPH) (aOR = 1.25, 95% CI: 1.06; 1.61). In men, lipoprotein(a) was associated with degree of stenosis (β = 0.58, 95% CI: 0.04; 1.12). Rs10455872 was significantly associated with increased calcification volume (β = 1.07, 95% CI: 0.25; 1.89) and absence of plaque ulceration (aOR = 0.25, 95% CI: 0.04; 0.93). T3888P was associated with absence of LRNC (aOR = 0.36, 95% CI: 0.16; 0.78) and smaller maximum vessel wall area (β = -10.24, 95%CI: -19.03; -1.44).

CONCLUSIONS

In patients with symptomatic carotid artery stenosis, increased lipoprotein(a) levels were associated with degree of stenosis, and IPH, LRNC, and TRFC, known as vulnerable plaque characteristics, in the carotid artery. T3888P was associated with lower LRNC prevalence and smaller maximum vessel wall area. Further research in larger study populations is needed to confirm these results.

The lipid paradox in neuroprogressive disorders: Causes and consequences

Chronic systemic inflammation is associated with an increased risk of cardiovascular disease in an environment of low low-density lipoprotein (LDL) and low total cholesterol and with the pathophysiology of neuroprogressive disorders. The causes and consequences of this lipid paradox are explored. Circulating activated neutrophils can release inflammatory molecules such as myeloperoxidase and the pro-inflammatory cytokines interleukin-1 beta, interleukin-6 and tumour necrosis factor-alpha. Since activated neutrophils are associated with atherosclerosis and cardiovascular disease and with major depressive disorder, bipolar disorder and schizophrenia, it seems reasonable to hypothesise that the inflammatory molecules released by them may act as mediators of the link between systemic inflammation and the development of atherosclerosis in neuroprogressive disorders. This hypothesis is tested by considering the association at a molecular level of systemic inflammation with increased LDL oxidation; increased small dense LDL levels; increased lipoprotein (a) concentration; secretory phospholipase A₂ activation; cytosolic phospholipase A₂ activation; increased platelet activation; decreased apolipoprotein A1 levels and function; decreased paroxonase-1 activity; hyperhomocysteinaemia; and metabolic endotoxaemia. These molecular mechanisms suggest potential therapeutic targets.

The impact of race and ethnicity on lipoprotein(a) levels and cardiovascular risk

PURPOSE OF REVIEW

Lipoprotein(a) [Lp(a)] is a plasma circulating apoB100 (apoB) containing lipoprotein. It has a unique glycoprotein bound to the apoB100, apolipoprotein(a) [apo(a)]. The majority of the population expresses two apo(a) isoforms, when bound to apoB100 they create two circulating Lp(a) particles. Lp(a) levels are genetically determined and epidemiological studies have established elevated levels of Lp(a) to be a causal risk factor of cardiovascular disease (CVD). Lp(a) levels differ across racial groups and Blacks of Sub-Saharan decent have higher levels when compared to white. In comparison to white populations, studies in minorities are less represented in the published literature. Additionally, there is a lack of standardization in the commercial assays used to measured Lp(a) levels, and hence it is difficult to assess risk based on individual Lp(a) levels, but risk seems to occur in the upper percentiles of the population.

RECENT FINDINGS

A recent study using data from the UK biobank highlights the racial differences in Lp(a) levels and the increase risk in CVD amongst all races.

SUMMARY

This review will highlight Lp(a) biology and physiology with a focus on available data from racially diverse cohorts. There is a need to perform studies in diverse populations to understand if they are at higher risk than whites are.

Effectiveness of proprotein convertase subtilisin/kexin-9 monoclonal antibody treatment on plasma lipoprotein(a) concentrations in patients with elevated lipoprotein(a) attending a clinic

BACKGROUND

Lipoprotein(a) (Lp[a]) is a causal risk factor for atherosclerotic cardiovascular disease (ASCVD). Proprotein convertase subtilisin/kexin-9 monoclonal antibodies (PCSK9mAbs) can lower Lp(a) levels in clinical trials, but their effects in patients with elevated Lp(a) in clinical practice remain unclear.

AIMS

To investigate the effectiveness and safety of PCSK9mAbs in lowering plasma Lp(a) in patients with elevated Lp(a) concentrations in a lipid clinic.

METHODS

This was an open-label study of 53 adult patients with elevated Lp(a) concentration (≥0.5 g/L). Clinical, biochemical, and safety data were collected before and on treatment with evolocumab or alirocumab over a mean period of 11 months.

RESULTS

Treatment with a PCSK9mAb resulted in a significant reduction of 0.29 g/L (-22%) in plasma Lp(a) concentration (p<.001). There were also significant reductions in low-density lipoprotein-cholesterol (LDL-C) (-53%), remnant-cholesterol (-12%) and apolipoprotein B (-43%) concentrations. The change in Lp(a) concentration was significantly different from a comparable group of 35 patients with elevated Lp(a) who were not treated with a PCSK9mAb (-22% vs. -2%, p<.001). The reduction in Lp(a) concentration was not associated with the corresponding changes in LDL-C, remnant-cholesterol, and apolipoprotein B (p>.05 in all). 7.5% and 47% of the patients attained a target concentration of Lp(a) <0.5 g/L and LDL-C <1.8 mmol/L, respectively. PCSK9mAbs were well tolerated, the common adverse effects being pharyngitis (9.4%), nasal congestion (7.6%), myalgia (9.4%), diarrhoea (7.6%), arthralgia (9.4%) and injection site reactions (11%).

CONCLUSION

PCSK9mAbs can effectively and safely lower plasma Lp(a) concentrations in patients with elevated Lp(a) in clinical practice; the impact of the fall in Lp(a) on ASCVD outcomes requires further investigation.

Low lipoprotein(a) levels and risk of disease in a large, contemporary, general population study

AIMS

With the current focus on lipoprotein(a) as a likely causal risk factor for cardiovascular disease and new drugs potentially on the market to lower lipoprotein(a) levels, the safety of lowering lipoprotein(a) to low levels becomes increasingly important. We tested whether low levels of lipoprotein(a) and corresponding LPA genotypes associate with major disease groups including cancers and infectious disease.

METHODS AND RESULTS

We included 109 440 individuals from the Copenhagen General Population Study. For main World Health Organization International Classification of Diseases 10th edition chapter diseases, the only concordant association of low levels of lipoprotein(a) plasma levels and corresponding LPA genotypes with risk of disease was with low risk of diseases of the circulatory system. Furthermore, no concordant association of low levels of lipoprotein(a) plasma levels and corresponding LPA genotypes with the risk of any cancer (i.e. cancer subtypes combined) or infectious disease was seen. The hazard ratio for the risk of any cancer was 1.06 [95% confidence interval (CI): 0.97-1.15] for the first vs. the fourth quartile of lipoprotein(a), 1.02 (0.97-1.07) for the fourth vs. the first quartile of KIV-2 number of repeats, and 1.01 (0.96-1.07) for rs10455872 non-carriers vs. carriers. The corresponding hazard ratios for the risk of hospitalization for infection were 1.05 (95% CI: 0.99-1.10), 1.02 (0.98-1.07), and 0.97 (0.93-1.03), respectively.

CONCLUSION

In a large, contemporary, general population cohort, apart from the well-established association with cardiovascular disease, low levels of lipoprotein(a) and corresponding LPA genotypes did not concordantly associate with any major disease groups including cancers and infections. There is no safety signal from our results to indicate that low levels of lipoprotein(a) are harmful.

Quantifying atherogenic lipoproteins for lipid-lowering strategies: consensus-based recommendations from EAS and EFLM

The joint consensus panel of the European Atherosclerosis Society (EAS) and the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) recently addressed present and future challenges in the laboratory diagnostics of atherogenic lipoproteins. Total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDLC), LDL cholesterol (LDLC), and calculated non-HDLC (=total - HDLC) constitute the primary lipid panel for estimating risk of atherosclerotic cardiovascular disease (ASCVD) and can be measured in the nonfasting state. LDLC is the primary target of lipid-lowering therapies. For on-treatment follow-up, LDLC shall be measured or calculated by the same method to attenuate errors in treatment decisions due to marked between-method variations. Lipoprotein(a) [Lp(a)]-cholesterol is part of measured or calculated LDLC and should be estimated at least once in all patients at risk of ASCVD, especially in those whose LDLC declines poorly upon statin treatment. Residual risk of ASCVD even under optimal LDL-lowering treatment should be also assessed by non-HDLC or apolipoprotein B (apoB), especially in patients with mild-to-moderate hypertriglyceridemia (2-10 mmol/L). Non-HDLC includes the assessment of remnant lipoprotein cholesterol and shall be reported in all standard lipid panels. Additional apoB measurement can detect elevated LDL particle (LDLP) numbers often unidentified on the basis of LDLC alone. Reference intervals of lipids, lipoproteins, and apolipoproteins are reported for European men and women aged 20-100 years. However, laboratories shall flag abnormal lipid values with reference to therapeutic decision thresholds.

Lipoprotein(a) lowering by alirocumab reduces the total burden of cardiovascular events independent of low-density lipoprotein cholesterol lowering: ODYSSEY OUTCOMES trial

Aims

Lipoprotein(a) concentration is associated with first cardiovascular events in clinical trials. It is unknown if this relationship holds for total (first and subsequent) events. In the ODYSSEY OUTCOMES trial in patients with recent acute coronary syndrome (ACS), the proprotein convertase subtilisin/kexin type 9 inhibitor alirocumab reduced lipoprotein(a), low-density lipoprotein cholesterol (LDL-C), and cardiovascular events compared with placebo. This post hoc analysis determined whether baseline levels and alirocumab-induced changes in lipoprotein(a) and LDL-C [corrected for lipoprotein(a) cholesterol] independently predicted total cardiovascular events.

Methods and results

Cardiovascular events included cardiovascular death, non-fatal myocardial infarction, stroke, hospitalization for unstable angina or heart failure, ischaemia-driven coronary revascularization, peripheral artery disease events, and venous thromboembolism. Proportional hazards models estimated relationships between baseline lipoprotein(a) and total cardiovascular events in the placebo group, effects of alirocumab treatment on total cardiovascular events by baseline lipoprotein(a), and relationships between lipoprotein(a) reduction with alirocumab and subsequent risk of total cardiovascular events. Baseline lipoprotein(a) predicted total cardiovascular events with placebo, while higher baseline lipoprotein(a) levels were associated with greater reduction in total cardiovascular events with alirocumab (hazard ratio P  _trend = 0.045). Alirocumab-induced reductions in lipoprotein(a) (median −5.0 [−13.6, 0] mg/dL) and corrected LDL-C (median −51.3 [−67.1, −34.0] mg/dL) independently predicted lower risk of total cardiovascular events. Each 5-mg/dL reduction in lipoprotein(a) predicted a 2.5% relative reduction in cardiovascular events.

Conclusion

Baseline lipoprotein(a) predicted the risk of total cardiovascular events and risk reduction by alirocumab. Lipoprotein(a) lowering contributed independently to cardiovascular event reduction, supporting the concept of lipoprotein(a) as a treatment target after ACS.

Low-density lipoproteins cause atherosclerotic cardiovascular disease: pathophysiological, genetic, and therapeutic insights: a consensus statement from the European Atherosclerosis Society Consensus Panel

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Correlations between lipoprotein(a) gene polymorphisms and calcific aortic valve disease and coronary heart disease in Han Chinese

Objective

To investigate the relationship between lipoprotein(a) gene (LPA) polymorphisms and calcific aortic valve disease (CAVD) and coronary heart disease (CHD) in Han Chinese.

Methods

A total of 148 patients were recruited (n = 71 with CAVD and n = 77 with CHD) based on a diagnosis achieved using color Doppler echocardiography, coronary angiography, or computed tomography angiography. Seventy-one control individuals without CAVD or CHD were also recruited. Biomarkers including levels of lipoprotein(a) [Lp(a)], low-density lipoprotein and high-density lipoprotein cholesterol, apolipoprotein A1, and apolipoprotein B were tested. LPA polymorphisms rs10455872, rs6415084, rs3798221, and rs7770628 were analyzed using SNaPshot SNP.

Results

Lp(a) levels were significantly higher in CAVD and CHD groups compared with controls. There was no significant difference in the allelic frequency distribution of rs3798221, rs7770628, or rs6415084 between CHD, CAVD, and control groups. Linear regression showed that rs3798221, rs7770628, and rs6415084 were associated with increased Lp(a) concentrations. Two CAVD patients among the 219 participants carried AG minor alleles at rs10455872, while the remainder carried AA minor alleles.

Conclusion

rs3798221, rs6415084, and rs7770628 polymorphisms within LPA are associated with higher Lp(a) plasma levels, which correlate with increased CAVD and CHD risks.