Lipoprotein(a): An underestimated inflammatory mastermind

Elevated lipoprotein(a) levels: A crucial determinant of cardiovascular disease risk and target for emerging therapies

Cardiovascular disease (CVD) remains a significant global health challenge despite advancements in prevention and treatment. Elevated Lipoprotein(a) [Lp(a)] levels have emerged as a crucial risk factor for CVD and aortic stenosis, affecting approximately 20 of the global population. Research over the last decade has established Lp(a) as an independent genetic contributor to CVD and aortic stenosis, beginning with Kare Berg's discovery in 1963. This has led to extensive exploration of its molecular structure and pathogenic roles. Despite the unknown physiological function of Lp(a), studies have shed light on its metabolism, genetics, and involvement in atherosclerosis, inflammation, and thrombosis. Epidemiological evidence highlights the link between high Lp(a) levels and increased cardiovascular morbidity and mortality. Newly emerging therapies, including pelacarsen, zerlasiran, olpasiran, muvalaplin, and lepodisiran, show promise in significantly lowering Lp(a) levels, potentially transforming the management of cardiovascular disease. However, further research is essential to assess these novel therapies' long-term efficacy and safety, heralding a new era in cardiovascular disease prevention and treatment and providing hope for at-risk patients.

Lipoprotein(a) and Long-Term Plaque Progression, Low-Density Plaque, and Pericoronary Inflammation

Importance

Lipoprotein(a) (Lp[a]) is a causal risk factor for cardiovascular disease; however, long-term effects on coronary atherosclerotic plaque phenotype, high-risk plaque formation, and pericoronary adipose tissue inflammation remain unknown.

Objective

To investigate the association of Lp(a) levels with long-term coronary artery plaque progression, high-risk plaque, and pericoronary adipose tissue inflammation.

Design, Setting, and Participants

This single-center prospective cohort study included 299 patients with suspected coronary artery disease (CAD) who underwent per-protocol repeated coronary computed tomography angiography (CCTA) imaging with an interscan interval of 10 years. Thirty-two patients were excluded because of coronary artery bypass grafting, resulting in a study population of 267 patients. Data for this study were collected from October 2008 to October 2022 and analyzed from March 2023 to March 2024.

Exposures

The median scan interval was 10.2 years. Lp(a) was measured at follow-up using an isoform-insensitive assay. CCTA scans were analyzed with a previously validated artificial intelligence-based algorithm (atherosclerosis imaging-quantitative computed tomography).

Main Outcome and Measures

The association between Lp(a) and change in percent plaque volumes was investigated in linear mixed-effects models adjusted for clinical risk factors. Secondary outcomes were presence of low-density plaque and presence of increased pericoronary adipose tissue attenuation at baseline and follow-up CCTA imaging.

Results

The 267 included patients had a mean age of 57.1 (SD, 7.3) years and 153 were male (57%). Patients with Lp(a) levels of 125 nmol/L or higher had twice as high percent atheroma volume (6.9% vs 3.0%; P = .01) compared with patients with Lp(a) levels less than 125 nmol/L. Adjusted for other risk factors, every doubling of Lp(a) resulted in an additional 0.32% (95% CI, 0.04-0.60) increment in percent atheroma volume during the 10 years of follow-up. Every doubling of Lp(a) resulted in an odds ratio of 1.23 (95% CI, 1.00-1.51) and 1.21 (95% CI, 1.01-1.45) for the presence of low-density plaque at baseline and follow-up, respectively. Patients with higher Lp(a) levels had increased pericoronary adipose tissue attenuation around both the right circumflex artery and left anterior descending at baseline and follow-up.

Conclusions and Relevance

In this long-term prospective serial CCTA imaging study, higher Lp(a) levels were associated with increased progression of coronary plaque burden and increased presence of low-density noncalcified plaque and pericoronary adipose tissue inflammation. These data suggest an impact of elevated Lp(a) levels on coronary atherogenesis of high-risk, inflammatory, rupture-prone plaques over the long term.

Parathyroid hormone-PTH1R signaling in cardiovascular disease and homeostasis

Primary hyperparathyroidism (pHPT) afflicts our aging population with an incidence approaching 50 per 100 000 patient-years at a female:male ratio of ~3:1. Decisions surrounding surgical management are currently driven by age, hypercalcemia severity, presence of osteoporosis, renal insufficiency, or hypercalciuria with or without nephrolithiasis. Cardiovascular (CV) disease (CVD) is not systematically considered. This is notable since the parathyroid hormone (PTH) 1 receptor (PTH1R) is biologically active in the vasculature, and adjusted CV mortality risk is increased almost threefold in individuals with pHPT who do not meet contemporary recommendations for surgical cure. We provide an overview of epidemiology, pharmacology, and physiology that highlights the need to: (i) identify biomarkers that establish a healthy 'set point' for CV PTH1R signaling tone; (ii) better understand the pharmacokinetic-pharmacodynamic (PK-PD) relationships of PTH1R ligands in CV homeostasis; and (iii) incorporate CVD risk assessment into the management of hyperparathyroidism.

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

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

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).

Discrimination and net-reclassification of cardiovascular disease risk with Lipoprotein(a) levels: The ATTICA study (2002-2022)

BACKGROUND

Lipoprotein(a) [Lp(a)] is a recognized as risk factor for atherosclerotic cardiovascular disease (ASCVD). However, its influence on clinical risk evaluations remains unclear.

OBJECTIVE

This study aimed to determine whether Lp(a) improves CVD risk prediction among apparently healthy adults from the general population.

METHODS

In 2002, n = 3,042 adults free of CVD, residing in Athens metropolitan area, in Greece, were recruited. A 20-year follow-up was conducted in 2022, comprising n = 2,169 participants, of which n = 1,988 had complete data for CVD incidence.

RESULTS

Lp(a) levels were significantly associated with 20-year ASCVD incidence in the crude model (Hazard Ratio per 1 mg/dL: 1.004, p = 0.048), but not in multi-adjusted models considering demographic, lifestyle, and clinical factors. Adding Lp(a) to the Reynolds Risk Score (RRS) and Framingham Risk Score (FRS) variables resulted in positive Net Reclassification Improvement (NRI) values (0.159 and 0.160 respectively), indicating improved risk classification. Mediation analysis suggested that C-reactive protein, Interleukin-6, and Fibrinogen mediate the relationship between Lp(a) and ASCVD. No significant interaction was observed between Lp(a) and potential moderators.

CONCLUSION

Lp(a) levels can predict 20-year CVD outcomes and improve CVD risk prediction within the general population, possibly via the intricate relationship between Lp(a), systemic inflammation, atherothrombosis.

Consideration and Application of Lipoprotein(a) in the Risk Assessment of Atherosclerotic Cardiovascular Disease Risk in Adults

Lipoprotein(a) (Lp[a]) is an low-density lipoprotein (LDL)-like particle in which apolipoprotein (apo) B is covalently bound to a plasminogen-like molecule called apo(a). A High level of Lp(a) has been demonstrated to be an independent, causal, and prevalent risk factor for atherosclerotic cardiovascular disease (ASCVD), as well as aortic valve disease, through mechanisms that promote atherogenesis, inflammation, and thrombosis. With reliable and accessible assays, Lp(a) level has been established to be associated linearly with the risk for ASCVD. The 2021 Canadian Cardiovascular Society Dyslipidemia Guidelines recommend measuring an Lp(a) level once in a person's lifetime as part of the initial lipid screening. The aim of this review is to provide an update and overview of the utility and application of Lp(a) level in the assessment and treatment of adults at risk for ASCVD, consistent with this guideline recommendation.

Low circulatory levels of total cholesterol, HDL-C and LDL-C are associated with death of patients with sepsis and critical illness: systematic review, meta-analysis, and perspective of observational studies

BACKGROUND

Mechanistic studies have established a biological role of sterol metabolism in infection and immunity with clinical data linking deranged cholesterol metabolism during sepsis with poorer outcomes. In this systematic review we assess the relationship between biomarkers of cholesterol homeostasis and mortality in critical illness.

METHODS

We identified articles by searching a total of seven electronic databases from inception to October 2023. Prospective observational cohort studies included those subjects who had systemic cholesterol (Total Cholesterol (TC), HDL-C or LDL-C) levels assessed on the first day of ICU admission and short-term mortality recorded. Meta-analysis and meta-regression were used to evaluate overall mean differences in serum cholesterol levels between survivors and non-survivors. Study quality was assessed using the Newcastle-Ottawa Scale.

FINDINGS

From 6469 studies identified by searches, 24 studies with 2542 participants were included in meta-analysis. Non-survivors had distinctly lower HDL-C at ICU admission -7.06 mg/dL (95% CI -9.21 to -4.91, p < 0.0001) in comparison with survivors. Corresponding differences were also seen less robustly for TC -21.86 mg/dL (95% CI -31.23 to -12.49, p < 0.0001) and LDL-C -8.79 mg/dL (95% CI, -13.74 to -3.83, p = 0.0005).

INTERPRETATION

Systemic cholesterol levels (TC, HDL-C and LDL-C) on admission to critical care are inversely related to mortality. This finding is consistent with the notion that inflammatory and metabolic setpoints are coupled, such that the maladaptive-setpoint changes of cholesterol in critical illness are related to underlying inflammatory processes. We highlight the potential of HDL-biomarkers as early predictors of severity of illness and emphasise that future research should consider the metabolic and functional heterogeneity of HDLs.

FUNDING

EU-ERDF-Welsh Government Ser Cymru programme, BBSRC, and EU-FP7 ClouDx-i project (PG).

Lipoprotein(a) and Long-Term Recurrent Infarction After an Acute Myocardial Infarction

Lipoprotein(a) (Lp[a]) is an emerging risk factor for incident ischemic heart disease. However, its role in risk stratification in in-hospital survivors to an index acute myocardial infarction (AMI) is scarcer, especially for predicting the risk of long-term recurrent AMI. We aimed to assess the relation between Lp(a) and very long-term recurrent AMI after an index episode of AMI. It is a retrospective analysis that included 1,223 consecutive patients with an AMI discharged from October 2000 to June 2003 in a single-teaching center. Lp(a) was assessed during index admission in all cases. The relation between Lp(a) at discharge and total recurrent AMI was evaluated through negative binomial regression. The mean age of the patients was 67.0 ± 12.3 years, 379 (31.0%) were women, and 394 (32.2%) were diabetic. The index event was more frequently non-ST-segment elevation myocardial infarction (66.0%). The median Lp(a) was 28.8 (11.8 to 63.4) mg/100 ml. During a median follow-up of 9.9 (4.6 to 15.5) years, 813 (66.6%) deaths and 1,205 AMI in 532 patients (43.5%) occurred. Lp(a) values were not associated with an increased risk of long-term all-cause mortality (p = 0.934). However, they were positively and nonlinearly associated with an increased risk of total long-term reinfarction (p = 0.016). In the subgroup analysis, there was no evidence of a differential effect for the most prevalent subgroups. In conclusion, after an AMI, elevated Lp(a) values assessed during hospitalization were associated with an increased risk of recurrent reinfarction in the very long term. Further prospective studies are warranted to evaluate their clinical implications.

Lipoprotein(a), Interleukin-6 inhibitors, and atherosclerotic cardiovascular disease: Is there an association?

Background and aims

Lipoprotein(a) [Lp(a)] and interleuking-6 (IL-6), an inflammation biomarker, have been established as distinct targets of the residual atherosclerotic cardiovascular disease (ASCVD) risk. We aimed to investigate the association between them, and the potential clinical implications in ASCVD prevention.

Methods

A literature search was conducted in PubMed until December 31st, 2022, using relevant keywords.

Results

Elevated lipoprotein(a) [Lp(a)] levels constitute the most common inherited lipid disorder associated with ASCVD. Although Lp(a) levels are mostly determined genetically by the LPA gene locus, they may be altered by acute conditions of stress and chronic inflammatory diseases. Considering its resemblance with low-density lipoproteins, Lp(a) is involved in atherosclerosis, but it also exerts oxidative, thrombotic, antifibrinolytic and inflammatory properties. The cardiovascular efficacy of therapies lowering Lp(a) by >90% is currently investigated. On the other hand, interleukin (IL)-1b/IL-6 pathway also plays a pivotal role in atherosclerosis and residual ASCVD risk. IL-6 receptor inhibitors [IL-6(R)i] lower Lp(a) by 16-41%, whereas ongoing trials are investigating their potential anti-atherosclerotic effect. The Lp(a)-lowering effect of IL-6(R)i might be attributed to the inhibition of the IL-6 response elements in the promoter region of the LPA gene.

Conclusions

Although the effect of IL-6(R)i on Lp(a) levels is inferior to that of available Lp(a)-lowering therapies, the dual effect of the former on both inflammation and apolipoprotein (a) synthesis may prove of equal or even greater significance when it comes ASCVD outcomes. More trials are required to establish IL-6(R)i in ASCVD prevention and elucidate their interplay with Lp(a) as well as its clinical significance.

High levels of lipoprotein(a) in transgenic mice exacerbate atherosclerosis and promote vulnerable plaque features in a sex-specific manner

BACKGROUND AND AIMS

Despite increased clinical interest in lipoprotein(a) (Lp(a)), many questions remain about the molecular mechanisms by which it contributes to atherosclerotic cardiovascular disease. Existing murine transgenic (Tg) Lp(a) models are limited by low plasma levels of Lp(a) and have not consistently shown a pro-atherosclerotic effect of Lp(a).

METHODS

We generated Tg mice expressing both human apolipoprotein(a) (apo(a)) and human apoB-100, with pathogenic levels of plasma Lp(a) (range 87-250 mg/dL). Female and male Lp(a) Tg mice (Tg(LPA+/0;APOB+/0)) and human apoB-100-only controls (Tg(APOB+/0)) (n = 10-13/group) were fed a high-fat, high-cholesterol diet for 12 weeks, with Ldlr knocked down using an antisense oligonucleotide. FPLC was used to characterize plasma lipoprotein profiles. Plaque area and necrotic core size were quantified and immunohistochemical assessment of lesions using a variety of cellular and protein markers was performed.

RESULTS

Male and female Tg(LPA+/0;APOB+/0) and Tg(APOB+/0) mice exhibited proatherogenic lipoprotein profiles with increased cholesterol-rich VLDL and LDL-sized particles and no difference in plasma total cholesterol between genotypes. Complex lesions developed in the aortic sinus of all mice. Plaque area (+22%), necrotic core size (+25%), and calcified area (+65%) were all significantly increased in female Tg(LPA+/0;APOB+/0) mice compared to female Tg(APOB+/0) mice. Immunohistochemistry of lesions demonstrated that apo(a) deposited in a similar pattern as apoB-100 in Tg(LPA+/0;APOB+/0) mice. Furthermore, female Tg(LPA+/0;APOB+/0) mice exhibited less organized collagen deposition as well as 42% higher staining for oxidized phospholipids (OxPL) compared to female Tg(APOB+/0) mice. Tg(LPA+/0;APOB+/0) mice had dramatically higher levels of plasma OxPL-apo(a) and OxPL-apoB compared to Tg(APOB+/0) mice, and female Tg(LPA+/0;APOB+/0) mice had higher plasma levels of the proinflammatory cytokine MCP-1 (+3.1-fold) compared to female Tg(APOB+/0) mice.

CONCLUSIONS

These data suggest a pro-inflammatory phenotype exhibited by female Tg mice expressing Lp(a) that appears to contribute to the development of more severe lesions with greater vulnerable features.

Is there a benefit of aspirin therapy for primary prevention to reduce the risk of atherosclerotic cardiovascular disease in patients with elevated Lipoprotein (a)-A review of the evidence

Aspirin has long been recognized as a beneficial treatment for atherosclerotic cardiovascular disease (ASCVD) due to its antiplatelet effects. However, there is a need to more precisely identify individuals who would benefit from aspirin therapy for primary prevention in order to reduce the risk of ASCVD. Those with elevated lipoprotein (a) [Lp(a)] levels are at increased risk of ASCVD. In this article, we provide an overview of studies that have explored the use of aspirin therapy in individuals with elevated Lp(a). We discuss the potential mechanisms by which aspirin therapy may reduce ASCVD risk, and present a review of the data on the effectiveness of aspirin therapy in reducing ASCVD risk in individuals with elevated Lp(a). The presented evidence suggests that individuals with elevated Lp(a) benefit more from aspirin therapy for reduction of ASCVD events than the general population.

Elevated Lipoprotein(a) Levels and Atrial Fibrillation: A Systematic Review

Objective

The role of lipoprotein(a) (Lp[a]) as a possibly causal risk factor for atherosclerotic cardiovascular disease has been well established. However, the clinical evidence regarding the association between Lp(a) levels and atrial fibrillation (AF) remains limited and inconsistent. This study aimed to analyze the association between elevated Lp(a) levels or single-nucleotide polymorphisms (SNPs) related to high levels of Lp(a) and AF.

Methods

This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A literature search was performed to identify studies that evaluated the association between Lp(a) levels or SNPs related to high levels of Lp(a) and AF. Observational studies with a cross-sectional, case-control, or cohort design were included in this systematic review, without limitations according to language, country, or publication type.

Results

Eleven observational studies including 1,246,817 patients were eligible for this systematic review. Two cross-sectional studies, 5 prospective/retrospective cohort studies, and 4 Mendelian randomization studies were analyzed. Two cross-sectional studies that compared Lp(a) levels between patients with and without AF showed conflicting results. Cohort studies that evaluated the incidence of AF according to Lp(a) levels showed different results: no association (3 studies), a positive association (1 study), and an inverse relationship (1 study). Finally, Mendelian randomization studies also showed heterogeneous results (positive association: 2 studies; inverse association: 1 study; no association: 1 study).

Conclusion

Although there could be an association between Lp(a) levels and AF, the results of the studies published to date are contradictory and not yet definitive. Therefore, further research should clarify this issue.

Improved arterial inflammation with high dose omega-3 fatty acids in patients with elevated lipoprotein(a): Selective effect of eicosapentaenoic acid?

Elevated lipoprotein(a) [Lp(a)] is a causal risk factor for atherosclerotic cardiovascular disease. However, there are no approved and effective treatments for lowering Lp(a) and the associated cardiovascular risks. Omega-3 fatty acids (ω-3FAs), primarily eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have both triglyceride-lowering and anti-inflammatory properties. This pilot study investigated the effect of high dose ω-3FAs (3.6 g/day) on arterial inflammation in 12 patients with elevated Lp(a) (> 0.5 g/L) and stable coronary artery disease (CAD) receiving cholesterol-lowering treatment. Arterial inflammation was determined using 18F-fluorodexoyglucose positron emission tomography/computed tomography before and after 12-weeks intervention. ω-3FAs significantly lowered plasma concentrations of triglycerides (-17%, p < 0.01), Lp(a) (-5%, p < 0.01) as well as aortic maximum standardized uptake value (SUVmax) (-4%, p < 0.05). The reduction in SUVmax was significantly inversely associated with average on-treatment EPA (r = -0.750, p < 0.01), but not DHA and triglyceride, concentrations. In conclusion, high dose ω-3FAs decrease arterial inflammation in patients with elevated Lp(a) and stable CAD, which may involve a direct arterial effect of EPA.

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.

The Concentration of PCSK9-Lp(a) Complexes and the Level of Blood Monocytes in Males with Coronary Atherosclerosis

In this study we analyzed the concentration of lipoprotein(a) (Lp(a)), PCSK9-Lp(a) complexes and the circulating monocyte subsets in coronary atherosclerosis. For this study, 257 patients with coronary atherosclerosis and 68 patients without stenotic atherosclerosis in the coronary, carotid and lower extremity arteries (control group) were enrolled. The monocyte subpopulations (classical CD14++CD16-, intermediate CD14++CD16+ and non-classical CD14+CD16++) were analyzed by direct immunofluorescence and flow cytometry. The Lp(a) and PCSK9-Lp(a) complexes in the serum were detected by ELISA. The concentration of Lp(a) was higher in the coronary atherosclerosis group compared with the controls (23.0 (9.1; 73.3) mg/dL versus 10.7 (4.7; 25.0) mg/dL, p < 0.05). No correlations between the level of Lp(a) and the concentration of the PCSK9-Lp(a) complexes, nor between the level of Lp(a) or PCSK9 and the total number of monocytes, were observed in either group. A slight positive correlation between the concentration of PCSK9-Lp(a) complexes and the absolute level of monocytes was obtained (r = 0.20, p = 0.002) in the patients with atherosclerosis due to the intermediate monocyte subsets (r = 0.33, p = 0.04). According to regression analysis, both the PCSK9-Lp(a) complexes concentration and BMI were related to the absolute number of blood monocytes in patients with atherosclerosis. Further studies are required to determine the pathogenetic contribution of PCSK9-Lp(a) complexes to the development of atherosclerosis.

Evidence and Uncertainties on Lipoprotein(a) as a Marker of Cardiovascular Health Risk in Children and Adolescents

Lipoprotein(a) (Lp(a)) is made up of apoprotein(a) (apo(a)) and an LDL-like particle. The LPA gene encodes apo(a) and thus determines the characteristics and amount of apo(a) and Lp(a). The proportion of Lp(a) in each individual is genetically determined and is only minimally modifiable by the environment or diet. Lp(a) has important pro-atherosclerotic and pro-inflammatory effects. It has been hypothesized that Lp(a) also has pro-coagulant and antifibrinolytic actions. For these reasons, high Lp(a) values are an important independent risk factor for cardiovascular disease and calcific aortic valve stenosis. Numerous studies have been performed in adults about the pathophysiology and epidemiology of Lp(a) and research is under way for the development of drugs capable of reducing Lp(a) plasma values. Much less information is available regarding Lp(a) in children and adolescents. The present article reviews the evidence on this topic. The review addresses the issues of Lp(a) changes during growth, the correlation between Lp(a) values in children and those in their parents, and between Lp(a) levels in children, and the presence of cardiovascular disease in the family. Gaining information on these points is particularly important for deciding whether Lp(a) assay may be useful for defining the cardiovascular risk in children, in order to plan a prevention program early.

High lipoprotein(a) levels and mitral valve disease: A systematic review

AIMS

The role of lipoprotein(a) [Lp(a)] as a possibly causal risk factor for atherosclerotic artery disease and aortic valve stenosis has been well established. However, the information available on the association between Lp(a) levels and mitral valve disease is limited and controversial. The main objective of the present study was to assess the association between Lp(a) levels and mitral valve disease.

DATA SYNTHESIS

This systematic review was performed according to PRISMA guidelines (PROSPERO CRD42022379044). A literature search was performed to detect studies that evaluated the association between Lp(a) levels or single-nucleotide polymorphisms (SNPs) related to high levels of Lp(a) and mitral valve disease, including mitral valve calcification and valve dysfunction. Eight studies including 1,011,520 individuals were considered eligible for this research. The studies that evaluated the association between Lp(a) levels and prevalent mitral valve calcification found predominantly positive results. Similar findings were reported in two studies that evaluated the SNPs related to high levels of Lp(a). Only two studies evaluated the association of Lp(a) and mitral valve dysfunction, showing contradictory results.

CONCLUSIONS

This research showed disparate results regarding the association between Lp(a) levels and mitral valve disease. The association between Lp(a) levels and mitral valve calcification seems more robust and is in line with the findings already demonstrated in aortic valve disease. New studies should be developed to clarify this topic.

Lipoprotein(a) and inflammation- pathophysiological links and clinical implications for cardiovascular disease

The role of lipoprotein(a) (Lp[a]) as a significant and possibly causal cardiovascular disease (CVD) risk factor has been well established. Many studies, mostly experimental, have supported inflammation as a mediator of Lp(a)-induced increase in CVD risk. Lp(a), mainly through oxidized phospholipids bound to its apolipoprotein(a) part, leads to monocyte activation and endothelial dysfunction. The relationship between Lp(a) and inflammation is bidirectional as Lp(a) levels, besides being associated with inflammatory properties, are regulated by inflammatory stimuli or anti-inflammatory treatment. Reduction of Lp(a) concentration, especially by potent siRNA agents, contributes to partial reversion of the Lp(a) related inflammatory profile. This review aims to present the current pathophysiological and clinical evidence of the relationship between Lp(a) and inflammation.

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.

Lipoprotein(a) in the Korean Pediatric Population Visiting Local Clinics and Hospitals

In this paper we investigate serum lipoprotein(a), an independent risk factor for cardiovascular disease in the Korean pediatric population. Visiting local clinics and hospitals, 600 lipoprotein(a) tests were performed on 416 Korean children and adolescents (124 boys and 292 girls), with a median age of 11.1 years (interquartile range, IQR, 9.8–13.9). The median lipoprotein(a) level was 21.5 nmol/L (IQR, 8.2–51.7). Among the 416 patients, the 90th percentile value of the initial lipoprotein(a) measurement was 107.8 nmol/L. The proportion of patients with lipoprotein(a) ≥ 100 nmol/L was 11.3%. The lipoprotein(a) level and the proportion of patients with lipoprotein(a) ≥ 100 nmol/L were not significantly different among sex, or age group. Among the 416 patients, 122 (29.3%, 21 boys and 101 girls) underwent at least two follow-up lipoprotein(a) measurements. The median follow-up period was 6.7 months (IQR, 5.5–11.8). The median lipoprotein(a) level across the 122 patients was 25 nmol/L (IQR 10.0–72.0). Among those patients, seven (5.7%) experienced an increase in serum lipoprotein(a) to ≥100 nmol/L during follow-up measurements. Further studies are needed in the Korean pediatric population in order to clarify the clinical significance of this change long-term.

Gene Expression Profiling of Markers of Inflammation, Angiogenesis, Coagulation and Fibrinolysis in Patients with Coronary Artery Disease with Very High Lipoprotein(a) Levels Treated with PCSK9 Inhibitors

Besides lipids, inflammation, angiogenesis, coagulation and fibrinolysis play very important roles in coronary artery disease (CAD). We measured gene expression of the inflammatory markers interleukin (IL)-1β (IL1B) and interferon (IFN)-γ (IFNG), vascular endothelial growth factor-A (VEGF-A) (VEGFA), and coagulation and fibrinolysis markers tissue factor (TF) (F3) and plasminogen activator inhibitor-1 (PAI-1) (SERPINE) in healthy controls and CAD patients with high lipoprotein(a) (Lp(a)). The aim of our study was to identify, first, if there is a difference in these markers between controls and patients; secondly, if these markers are associated with lipids; and third, what the influence of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors is on these markers. We included 124 subjects, 27 controls and 97 patients with CAD (30 in placebo and 67 in the PCSK9 group). Blood samples were collected for lipid and gene measurement. The results showed higher expression of IL1B (p < 0.0001), VEGFA (p < 0.0001), and F3 (p = 0.018) in controls in comparison with patients. Significant correlations were observed between IL1B and lipids. Treatment with PCSK9 inhibitors increased VEGFA (p < 0.0001) and F3 (p = 0.001), and decreased SERPINE (p = 0.043). The results of our study underpin the importance of IL-1β, VEGF-A and TF in CAD as well as the effect of PCSK9 treatment on these markers.

Non-genetic influences on lipoprotein(a) concentrations

An elevated level of lipoprotein(a) [Lp(a)] is a genetically regulated, independent, causal risk factor for cardiovascular disease. However, the extensive variability in Lp(a) levels between individuals and population groups cannot be fully explained by genetic factors, emphasizing a potential role for non-genetic factors. In this review, we provide an overview of current evidence on non-genetic factors influencing Lp(a) levels with a particular focus on diet, physical activity, hormones and certain pathological conditions. Findings from randomized controlled clinical trials show that diets lower in saturated fats modestly influence Lp(a) levels and often in the opposing direction to LDL cholesterol. Results from studies on physical activity/exercise have been inconsistent, ranging from no to minimal or moderate change in Lp(a) levels, potentially modulated by age and the type, intensity, and duration of exercise modality. Hormone replacement therapy (HRT) in postmenopausal women lowers Lp(a) levels with oral being more effective than transdermal estradiol; the type of HRT, dose of estrogen and addition of progestogen do not modify the Lp(a)-lowering effect of HRT. Kidney diseases result in marked elevations in Lp(a) levels, albeit dependent on disease stages, dialysis modalities and apolipoprotein(a) phenotypes. In contrast, Lp(a) levels are reduced in liver diseases in parallel with the disease progression, although population studies have yielded conflicting results on the associations between Lp(a) levels and nonalcoholic fatty liver disease. Overall, current evidence supports a role for diet, hormones and related conditions, and liver and kidney diseases in modifying Lp(a) levels.