Looking at Lp(a) and Related Cardiovascular Risk: from Scientific Evidence and Clinical Practice

Effects of proprotein convertase subtilisin-kexin type 9 inhibitors on inflammatory and hemostatic parameters in post myocardial infarction patients

Despite progress in treatment, elevated levels of low-density lipoprotein cholesterol (LDL-C) and lipoprotein (a) (Lp(a)), represent a significant part of the residual risk. Both are associated with inflammation and the coagulation fibrinolytic system. The purpose of our research was to evaluate the effect of proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) on lipid parameters and indicators of inflammation, coagulation and fibrinolysis. We included 100 post myocardial infarction (MI) patients with insufficiently controlled LDL-C values despite the maximum dose of statin, and highly elevated Lp(a). Patients received alirocumab or evolocumab (150 mg sc or 140 mg sc every two weeks, respectively), or placebo for 6 months. In patients receiving PCSK9i, a significant decrease in total cholesterol (TC), LDL-C, triglycerides (TG) and Lp(a), and an increase in high density lipoprotein cholesterol (p < 0.001 for all) was found. Before treatment, the concentrations of TC, LDL-C and TG correlated with the concentrations of thrombin activatable fibrinolysis inhibitor (r = 0.41, p < 0.001; r = 0.353, p < 0.001; r = 0.311, p = 0.003, respectively), and plasminogen activator inhibitor-1 (r = 0.302, p = 0.007; r = 0.218, p = 0.049; r = 0.278; p = 0.013, respectively). The concentrations of TC and LDL-C correlated with overall fibrinolytic potential (r = -0.220, p = 0.034; r = -0.207, p = 0.047, respectively). The concentration of TG was related to the concentration of interleukin 6 (r = 0.290, p = 0.004) and interleukin 8 (r = 0.332, p = 0.001). No correlations between Lp(a) and inflammatory or hemostatic variables were found. No associations were found after treatment. Our results show that inflammatory cytokines and fibrinolytic parameters are related to LDL-C and not Lp(a) in post-MI patients before and with neither of them following PCSK9i treatment. The trial registration number: NCT04613167, Date of registration: November 3, 2020.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Lipoprotein(a): Cardiovascular Disease, Aortic Stenosis and New Therapeutic Option

Atherosclerosis is a chronic and progressive inflammatory process beginning early in life with late clinical manifestation. This slow pathological trend underlines the importance to early identify high-risk patients and to treat intensively risk factors to prevent the onset and/or the progression of atherosclerotic lesions. In addition to the common Cardiovascular (CV) risk factors, new markers able to increase the risk of CV disease have been identified. Among them, high levels of Lipoprotein(a)-Lp(a)-lead to very high risk of future CV diseases; this relationship has been well demonstrated in epidemiological, mendelian randomization and genome-wide association studies as well as in meta-analyses. Recently, new aspects have been identified, such as its association with aortic stenosis. Although till recent years it has been considered an unmodifiable risk factor, specific drugs have been developed with a strong efficacy in reducing the circulating levels of Lp(a) and their capacity to reduce subsequent CV events is under testing in ongoing trials. In this paper we will review all these aspects: from the synthesis, clearance and measurement of Lp(a), through the findings that examine its association with CV diseases and aortic stenosis to the new therapeutic options that will be available in the next years.

Non-Lipid Effects of PCSK9 Monoclonal Antibodies on Vessel Wall

Elevated low density lipoprotein (LDL) cholesterol and lipoprotein(a) (Lp(a)) levels have an important role in the development and progression of atherosclerosis, followed by cardiovascular events. Besides statins and other lipid-modifying drugs, PCSK9 monoclonal antibodies are known to reduce hyperlipidemia. PCSK9 monoclonal antibodies decrease LDL cholesterol levels through inducing the upregulation of the LDL receptors and moderately decrease Lp(a) levels. In addition, PCSK9 monoclonal antibodies have shown non-lipid effects. PCSK9 monoclonal antibodies reduce platelet aggregation and activation, and increase platelet responsiveness to acetylsalicylic acid. Evolocumab as well as alirocumab decrease an incidence of venous thromboembolism, which is associated with the decrease of Lp(a) values. Besides interweaving in haemostasis, PCSK9 monoclonal antibodies play an important role in reducing the inflammation and improving the endothelial function. The aim of this review is to present the mechanisms of PCSK9 monoclonal antibodies on the aforementioned risk factors.

Assessment of Associations Between Serum Lipoprotein (a) Levels and Atherosclerotic Vascular Diseases in Hungarian Patients With Familial Hypercholesterolemia Using Data Mining and Machine Learning

Background and aims: Premature mortality due to atherosclerotic vascular disease is very high in Hungary in comparison with international prevalence rates, though the estimated prevalence of familial hypercholesterolemia (FH) is in line with the data of other European countries. Previous studies have shown that high lipoprotein(a)- Lp(a) levels are associated with an increased risk of atherosclerotic vascular diseases in patients with FH. We aimed to assess the associations of serum Lp(a) levels and such vascular diseases in FH using data mining methods and machine learning techniques in the Northern Great Plain region of Hungary.

Methods: Medical records of 590,500 patients were included in our study. Based on the data from previously diagnosed FH patients using the Dutch Lipid Clinic Network scores (≥7 was evaluated as probable or definite FH), we trained machine learning models to identify FH patients.

Results: We identified 459 patients with FH and 221 of them had data available on Lp(a). Patients with FH had significantly higher Lp(a) levels compared to non-FH subjects [236 (92.5; 698.5) vs. 167 (80.2; 431.5) mg/L, p < .01]. Also 35.3% of FH patients had Lp(a) levels >500 mg/L. Atherosclerotic complications were significantly more frequent in FH patients compared to patients without FH (46.6 vs. 13.9%). However, contrary to several other previous studies, we could not find significant associations between serum Lp(a) levels and atherosclerotic vascular diseases in the studied Hungarian FH patient group.

Conclusion: The extremely high burden of vascular disease is mainly explained by the unhealthy lifestyle of our patients (i.e., high prevalence of smoking, unhealthy diet and physical inactivity resulting in obesity and hypertension). The lack of associations between serum Lp(a) levels and atherosclerotic vascular diseases in Hungarian FH patients may be due to the high prevalence of these risk factors, that mask the deleterious effect of Lp(a).

Lipoprotein(a) and aortic valve stenosis: A casual or causal association?

AIMS

This review aims to provide an update of available methods for imaging calcification activity and potential therapeutic options.

DATA SYNTHESIS

Aortic valve calcification represents the most common heart valve condition requiring treatment among adults in Western societies. No medical therapies are proven to be effective in treating symptoms or reducing disease progression. Therefore, surgical or transcatheter aortic valve replacement remains the only available treatment option. Elevated circulating concentrations of lipoprotein(a) is strongly associated with degenerative aortic stenosis. This relationship was first observed in prospective observational studies, and the causal relationship was confirmed in genetic studies.

CONCLUSIONS

New therapeutic targets have been identified and new imaging techniques could be used to test the effectiveness of new agents and further clarify the pathophysiology of AVS. No therapy that specifically lowers Lp (a) levels has been approved for clinical use.

Lipoprotein(a)—The Crossroads of Atherosclerosis, Atherothrombosis and Inflammation

Increased lipoprotein(a) (Lp(a)) levels are an independent predictor of coronary artery disease (CAD), degenerative aortic stenosis (DAS), and heart failure independent of CAD and DAS. Lp(a) levels are genetically determinated in an autosomal dominant mode, with great intra- and inter-ethnic diversity. Most variations in Lp(a) levels arise from genetic variations of the gene that encodes the apolipoprotein(a) component of Lp(a), the LPA gene. LPA is located on the long arm of chromosome 6, within region 6q2.6–2.7. Lp(a) levels increase cardiovascular risk through several unrelated mechanisms. Lp(a) quantitatively carries all of the atherogenic risk of low-density lipoprotein cholesterol, although it is even more prone to oxidation and penetration through endothelia to promote the production of foam cells. The thrombogenic properties of Lp(a) result from the homology between apolipoprotein(a) and plasminogen, which compete for the same binding sites on endothelial cells to inhibit fibrinolysis and promote intravascular thrombosis. LPA has up to 70% homology with the human plasminogen gene. Oxidized phospholipids promote differentiation of pro-inflammatory macrophages that secrete pro-inflammatory cytokines (e. g., interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor-α). The aim of this review is to define which of these mechanisms of Lp(a) is predominant in different groups of patients.

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.

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.

Dyslipidemia Management in 2020: An Update on Diagnosis and Therapeutic Perspectives

Cardiovascular diseases are the leading cause of death in the modern world and dyslipidemia is one of the major risk factors. The current therapeutic strategies for cardiovascular diseases involve the management of risk factors, especially dyslipidemia and hypertension. Recently, the updated guidelines of dyslipidemia management were presented, and the newest data were included in terms of diagnosis, imaging, and treatment. In this targeted literature review, the researchers presented the most recent evidence on dyslipidemia management by including the current therapeutic goals for it. In addition, the novel diagnostic tools based on theranostics are shown. Finally, the future perspectives on treatment based on novel drug delivery systems and their potential to be used in clinical trials were also analyzed. It should be noted that dyslipidemia management can be achieved by the strict lifestyle change, i.e., by adopting a healthy life, and choosing the most suitable medication. This review can help medical professionals as well as specialists of other sciences to update their knowledge on dyslipidemia management, which can lead to better therapeutic outcomes and newer drug developments.

Increased cardiovascular risk associated with hyperlipoproteinemia (a) and the challenges of current and future therapeutic possibilities

Population, genetic, and clinical studies demonstrated a causative and continuous, from other plasma lipoproteins independent relationship between elevated plasma lipoprotein (a) [Lp(a)] concentration and the development of cardiovascular disease (CVD), mainly those related to athe-rosclerotic CVD, and calcific aortic stenosis. Currently, a strong international consensus is still lacking regarding the single value which would be commonly used to define hyperlipoproteinemia (a). Its prevalence in the general population is estimated to be in the range of 10%–35% in accordance with the most commonly used threshold levels (>30 or >50 mg/dL). Since elevated Lp(a) can be of special importance in patients with some genetic disorders, as well as in individuals with otherwise controlled major risk factors, the identification and establishment of the proper therapeutic interventions that would lower Lp(a) levels and lead to CVD risk reduction could be very important. The majority of the classical lipid-lowering agents (statins, ezetimibe, and fibrates), as well as nutraceuticals (CoQ10 and garlic), appear to have no significant effect on its plasma levels, whereas for the drugs with the demonstrated Lp(a)-lowering effects (aspirin, niacin, and estrogens), their clinical efficacy in reducing cardiovascular (CV) events has not been unequivocally proven yet. Both Lp(a) apheresis and proprotein convertase subtilisin/kexin type 9 inhibitors can reduce the plasma Lp(a) by approximately 20%–30% on average, in parallel with much larger reduction of low-density lipoprotein cholesterol (up to 70%), what puts us in a difficulty to conclude about the true contribution of lowered Lp(a) to the reduction of CV events. The most recent advancement in the field is the introduction of the novel apolipoprotein (a) [apo(a)] antisense oligonucleotide therapy targeting apo(a), which has already proven itself as being very effective in decreasing plasma Lp(a) (by even >90%), but should be further tested in clinical trials. The aim of this review was to present some of the most important accessible scientific data, as well as dilemmas related to the currently and potentially in the near future more widely available therapeutic options for the management of hyperlipoproteinemia (a).

Lipoprotein(a) concentration, genetic variants, apo(a) isoform size, and cellular cholesterol efflux in patients with elevated Lp(a) and coronary heart disease submitted or not to lipoprotein apheresis: An Italian case-control multicenter study on Lp(a)

BACKGROUND

Coronary artery disease (CAD) risk is greater with higher plasma lipoprotein(a)[Lp(a)] concentrations or smaller apoisoform size and putatively with increased cellular cholesterol loading capacity (CLC). The relationship between Lp(a) and CLC is not known. Information on Lp(a) polymorphisms in Italian patients is lacking.

OBJECTIVE

The objective of this study was to determine relationships between Lp(a) and CLC, the impact of lipoprotein apheresis (LA), and describe the genetic profile of Lp(a).

METHODS

We conducted a multicenter, observational study in Italian patients with hyperLp(a) and premature CAD with (n = 18)/without (n = 16) LA in which blood samples were analyzed for Lp(a) parameter and CLC. Genetic profiling of LPA was conducted in patient receiving LA.

RESULTS

Mean macrophage CLC of the pre-LA serum was significantly higher than that of normolipidemic controls (19.7 ± 0.9 μg/mg vs 16.01 ± 0.98 μg/mg of protein, respectively). After LA, serum macrophage CLC was markedly lower relative to preapheresis (16.1 ± 0.8 μg/mg protein; P = .003) and comparable with CLC of the normolipidemic serum. LA did not significantly affect average apo(a) isoform size distribution. No anthropometric or lipid parameters studied were related to serum CLC, but there was a relationship between CLC and the Lp(a) plasma concentration (P = .035). DNA analysis revealed a range of common genetic variants. Two rare, new variants were identified: LPA exon 21, c.3269C>G, p.Pro1090Arg, and rs41259144 p.Arg990Gln, c.2969G>A CONCLUSIONS: LA reduces serum Lp(a) and also reduces macrophage CLC. Novel genetic variants of the LPA gene were identified, and geographic variations were noted. The complexity of these polymorphisms means that genetic assessment is not a predictor of CAD risk in hyperLp(a).