Optimal therapy for reduction of lipoprotein(a)

Effect of different types and dosages of statins on plasma lipoprotein(a) levels: A network meta-analysis

BACKGROUND AND AIM

Studies differ with respect to the effects of statins and their on lipoprotein(a)[Lp(a)] levels. The aim of the present study was to resolve these differences by determining the effect of various types and dosages of statins on Lp(a) levels.

METHODS

We searched PubMed, Embase and the Cochrane library for randomized controlled trials (RCTs) investigating the efficacy of statins on plasma Lp(a) levels. Study selection, data extraction and risk of bias assessment were conducted independently by four authors. We conducted pairwise meta-analysis and network meta-analysis (NMA). Consistency models were applied to NMA and the ranking probabilities for each treatment's efficacy were calculated. Node-splitting analysis was used to test inconsistency. This study was registered with PROSPERO, number CRD42020167612.

RESULTS

Twenty RCTs with 23,605 participants were included, involving 11 interventions. Most of the included studies presented some risks of bias, especially risks of performance and detection bias. In the pairwise meta-analysis, pooled results showed a small but statistically significant difference between high-intensity rosuvastatin and placebo on Lp(a) levels (MD = 1.81, 95 % CI [0.43, 3.19], P = 0.01). In the NMA, different types and dosages of statins showed no significant effect on the level of Lp(a), and there was no obvious difference between them. Subgroup analysis based on different populations and treatment durations did not provide any statistically significant findings about different statins on Lp(a) levels. Node-splitting analysis showed that no significant inconsistency existed (P > 0.05).

CONCLUSIONS

Statins have no clinically significant effect on Lp(a) levels, and there is no significant difference in the effect on Lp(a) levels between different types and dosages of statins. Moderate-intensity pitavastatin tended to have the best effect on reducing Lp(a) levels; nevertheless, it was insignificant. Our findings highlight the necessity for further study of the effect of statins on Lp(a) levels in future studies.

Antisense lipoprotein[a] therapy: State-of-the-art and future perspectives

Several lines of evidence now attest that lipoprotein[a] (Lp[a]) is a significant risk factor for many cardiovascular disorders. This enigmatic lipoprotein, composed of a single copy of apolipoprotein B (apoB) and apolipoprotein[a] (apo [a]), expresses peculiar metabolism, virtually independent from lifestyle interventions. Several therapeutic options have hence been proposed for lowering elevated Lp[a] values, with or without concomitant effect on low density lipoprotein (LDL) particles, mostly encompassing statins, ezetimibe, nicotinic acid, lipoprotein apheresis, and anti-PCSK9 monoclonal antibodies. Since all these medical treatments have some technical and clinical drawbacks, a novel strategy is currently being proposed, based on the use of antisense apo[a] and/or apoB inhibitors. Although the role of these agents in hypercholesterolemic patients is now nearby entering clinical practice, the collection of information on Lp[a] is still underway. Preliminary evidence would suggest that apo[a] antisense therapy seems more appropriate in patients with isolated Lp[a] elevations, while apoB antisense therapy is perhaps more advisable in patients with isolated LDL elevations. In patients with concomitant elevations of Lp[a] and LDL, either combining the two apo[a] and apoB antisense therapies (a strategy which has never been tested), or the combination of well-known and relatively inexpensive drugs such as statins with antisense apo[a] inhibitors can be theoretically suggested. The results of an upcoming phase 3 study with antisense apo[a] inhibitors will hopefully provide definitive clues as to whether this approach may become the standard of care in patients with increased Lp[a] concentrations.

Lipoprotein(a) the Insurgent: A New Insight into the Structure, Function, Metabolism, Pathogenicity, and Medications Affecting Lipoprotein(a) Molecule

Lipoprotein(a) [Lp(a)], aka "Lp little a", was discovered in the 1960s in the lab of the Norwegian physician Kåre Berg. Since then, we have greatly improved our knowledge of lipids and cardiovascular disease (CVD). Lp(a) is an enigmatic class of lipoprotein that is exclusively formed in the liver and comprises two main components, a single copy of apolipoprotein (apo) B-100 (apo-B100) tethered to a single copy of a protein denoted as apolipoprotein(a) apo(a). Plasma levels of Lp(a) increase soon after birth to a steady concentration within a few months of life. In adults, Lp(a) levels range widely from <2 to 2500 mg/L. Evidence that elevated Lp(a) levels >300 mg/L contribute to CVD is significant. The improvement of isoform-independent assays, together with the insight from epidemiologic studies, meta-analyses, genome-wide association studies, and Mendelian randomization studies, has established Lp(a) as the single most common independent genetically inherited causal risk factor for CVD. This breakthrough elevated Lp(a) from a biomarker of atherosclerotic risk to a target of therapy. With the emergence of promising second-generation antisense therapy, we hope that we can answer the question of whether Lp(a) is ready for prime-time clinic use. In this review, we present an update on the metabolism, pathophysiology, and current/future medical interventions for high levels of Lp(a).

Lipoprotein(a) – Link between Atherogenesis and Thrombosis

Lipoprotein(a) – Lp(a) – is an independent risk factor for cardiovascular disease (CVD). Indeed, individuals with plasma concentrations of Lp(a) > 200 mg/l carry an increased risk of developing CVD. Circulating levels of Lp(a) are remarkably resistant to common lipid lowering therapies, currently available treatment for reduction of Lp(a) is plasma apheresis, which is costly and labour intensive. The Lp(a) molecule is composed of two parts: LDL/apoB-100 core and glycoprotein, apolipoprotein(a) – Apo(a), both of them can interact with components of the coagulation cascade, inflammatory pathways and blood vessel cells (smooth muscle cells and endothelial cells). Therefore, it is very important to determine the molecular pathways by which Lp(a) affect the vascular system in order to design therapeutics for targeting the Lp(a) cellular effects. This paper summarises the cellular effects and molecular mechanisms by which Lp(a) participate in atherogenesis, thrombogenesis, inflammation and development of cardiovascular diseases.

Impact of Lipoprotein (a) Levels on Long-Term Outcomes in Patients With Coronary Artery Disease and Left Ventricular Systolic Dysfunction

BACKGROUND

Serum levels of lipoprotein (a) (Lp(a)) could be a risk factor for adverse events in patients with coronary artery disease (CAD). However, the effect of Lp(a) on long-term outcomes in patients with left ventricular (LV) systolic dysfunction, possibly through the increased likelihood for development of heart failure (HF), remains to be elucidated. This study aimed to determine the prognostic impact of Lp(a) in patients with CAD and LV systolic dysfunction.

METHODS AND RESULTS

A total of 3,508 patients who underwent percutaneous coronary intervention were candidates. We analyzed 369 patients with LV systolic dysfunction (defined as LV ejection fraction <50%). They were assigned to groups according to a median level of Lp(a) (i.e., high Lp(a), ≥21.6 mg/dL, n=185; low Lp(a), <21.6 mg/dL, n=184). The primary outcome was a composite of all-cause death and readmission for acute coronary syndrome and/or HF. The median follow-up period was 5.1 years. Cumulative event-free survival was significantly worse for the group with high Lp(a) than for the group with low Lp(a) (P=0.005). In the multivariable analysis, a high Lp(a) level was an independent predictor of the primary outcomes (hazard ratio, 1.54; 95% confidence interval, 1.09-2.18; P=0.014).

CONCLUSIONS

A high Lp(a) value could be associated with long-term adverse clinical outcomes among patients with CAD and LV systolic dysfunction.

Can Lp(a) Lowering Against Background Statin Therapy Really Reduce Cardiovascular Risk?

PURPOSE OF REVIEW

The association between elevated plasma levels of lipoprotein (a) [Lp(a)] and atherosclerotic cardiovascular disease (ASCVD) has been discussed for many years. Recent genetic findings have confirmed that elevated Lp(a) similar to elevated LDL-cholesterol (LDL-C) might be causally related to premature ASCVD. Lp(a) is relatively refractory to lifestyle interventions. The results of studies with statins and their possible effect on Lp(a) are conflicting. Specific Lp(a) apheresis is used as a treatment against background statin therapy and can decrease Lp(a). The purpose of this review is to discuss whether new drugs which decrease Lp(a) can prevent ASCVD and decrease ASCVD mortality when applied in addition to statins.

RECENT FINDINGS

Some new LDL-C-lowering drugs such as mipomersen and lomitapide decrease elevated Lp(a) in addition to statins but they have some unpleasant adverse effects. Recently, an antisense oligonucleotide against apo(a), AKCEA-APO(a)Rx, has been shown to selectively decrease Lp(a). The most recent advance in LDL-C lowering are PCSK9 inhibitors. Alirocumab and evolocumab do not only significantly reduce LDL-C on top of maximally tolerated statin therapy and prevent ASCVD events, but also further decrease Lp(a). There is no data to indicate whether mipomersen, lomitapide, or IONIS-APO(a)-LRx decrease ASCVD events and mortality. Conclusive evidence is still lacking as to whether the treatment with PCSK9 inhibitors against background statin therapy actually additionally reduces ASCVD risk due to the lowering of Lp(a) or simply due to lowering LDL-C to levels much lower than high-intensity statin treatment as monotherapy. Ongoing trials will probably provide an answer to these questions.

Dietary natural products as emerging lipoprotein(a)-lowering agents

Elevated plasma lipoprotein(a) (Lp(a)) levels are associated with an increased risk of cardiovascular disease (CVD). Hitherto, niacin has been the drug of choice to reduce elevated Lp(a) levels in hyperlipidemic patients but its efficacy in reducing CVD outcomes has been seriously questioned by recent clinical trials. Additional drugs may reduce to some extent plasma Lp(a) levels but the lack of a specific therapeutic indication for Lp(a)-lowering limits profoundly reduce their use. An attractive therapeutic option is natural products. In several preclinical and clinical studies as well as meta-analyses, natural products, including l-carnitine, coenzyme Q ₁₀ , and xuezhikang were shown to significantly decrease Lp(a) levels in patients with Lp(a) hyperlipoproteinemia. Other natural products, such as pectin, Ginkgo biloba, flaxseed, red wine, resveratrol and curcuminoids can also reduce elevated Lp(a) concentrations but to a lesser degree. In conclusion, aforementioned natural products may represent promising therapeutic agents for Lp(a) lowering.

Rare thrombophilic conditions

Thrombophilia, either acquired or inherited, can be defined as a predisposition to developing thromboembolic complications. Since the discovery of antithrombin deficiency in the 1965, many other conditions have been described so far, which have then allowed to currently detect an inherited or acquired predisposition in approximately 60-70% of patients with thromboembolic disorders. These prothrombotic risk factors mainly include qualitative or quantitative defects of endogenous coagulation factor inhibitors, increased concentration or function of clotting proteins, defects in the fibrinolytic system, impaired platelet function, and hyperhomocysteinemia. In this review article, we aim to provide an overview on epidemiologic, clinic and laboratory aspects of both acquired and inherited rare thrombophilic risk factors, especially including dysfibrinogenemia, heparin cofactor II, thrombomodulin, lipoprotein(a), sticky platelet syndrome, plasminogen activator inhibitor-1 apolipoprotein E, tissue factor pathway inhibitor, paroxysmal nocturnal haemoglobinuria and heparin-induced thrombocytopenia.

Postprandial hyperglycemia and postprandial hypertriglyceridemia in type 2 diabetes

Postprandial glucose level is an independent risk factor for cardiovascular disease that exerts effects greater than glucose levels at fasting state, whereas increase in serum triglyceride level, under both fasting and postprandial conditions, contributes to the development of arteriosclerosis. Insulin resistance is a prevailing cause of abnormalities in postabsorptive excursion of blood glucose and postprandial lipid profile. Excess fat deposition renders a vicious cycle of hyperglycemia and hypertriglyceridemia in the postprandial state, and both of which are contributors to atherosclerotic change of vessels especially in patients with type 2 diabetes mellitus. Several therapeutic approaches for ameliorating each of these abnormalities have been attempted, including various antidiabetic agents or new compounds targeting lipid metabolism.

The metabolism of lipoprotein (a): an ever-evolving story

Lipoprotein (a) [Lp(a)] is characterized by apolipoprotein (a) [apo(a)] covalently bound to apolipoprotein B 100. It was described in human plasma by Berg et al. in 1963 and the gene encoding apo(a) (LPA) was cloned in 1987 by Lawn and colleagues. Epidemiologic and genetic studies demonstrate that increases in Lp(a) plasma levels increase the risk of atherosclerotic cardiovascular disease. Novel Lp(a) lowering treatments highlight the need to understand the regulation of plasma levels of this atherogenic lipoprotein. Despite years of research, significant uncertainty remains about the assembly, secretion, and clearance of Lp(a). Specifically, there is ongoing controversy about where apo(a) and apoB-100 bind to form Lp(a); which apoB-100 lipoproteins bind to apo(a) to create Lp(a); whether binding of apo(a) is reversible, allowing apo(a) to bind to more than one apoB-100 lipoprotein during its lifespan in the circulation; and how Lp(a) or apo(a) leave the circulation. In this review, we highlight past and recent data from stable isotope studies of Lp(a) metabolism, highlighting the critical metabolic uncertainties that exist. We present kinetic models to describe results of published studies using stable isotopes and suggest what future studies are required to improve our understanding of Lp(a) metabolism.

Lipoprotein(a) in patients with aortic stenosis: Insights from cardiovascular magnetic resonance

Background

Aortic stenosis is the most common age-related valvular pathology. Patients with aortic stenosis and myocardial fibrosis have worse outcome but the underlying mechanism is unclear. Lipoprotein(a) is associated with adverse cardiovascular risk and is elevated in patients with aortic stenosis. Although mechanistic pathways could link Lipoprotein(a) with myocardial fibrosis, whether the two are related has not been previously explored. In this study, we investigated whether elevated Lipoprotein(a) was associated with the presence of myocardial replacement fibrosis.

Methods

A total of 110 patients with mild, moderate and severe aortic stenosis were assessed by late gadolinium enhancement (LGE) cardiovascular magnetic resonance to identify fibrosis. Mann Whitney U tests were used to assess for evidence of an association between Lp(a) and the presence or absence of myocardial fibrosis and aortic stenosis severity and compared to controls. Univariable and multivariable linear regression analysis were undertaken to identify possible predictors of Lp(a).

Results

Thirty-six patients (32.7%) had no LGE enhancement, 38 (34.6%) had midwall enhancement suggestive of midwall fibrosis and 36 (32.7%) patients had subendocardial myocardial fibrosis, typical of infarction. The aortic stenosis patients had higher Lp(a) values than controls, however, there was no significant difference between the Lp(a) level in mild, moderate or severe aortic stenosis. No association was observed between midwall or infarction pattern fibrosis and Lipoprotein(a), in the mild/moderate stenosis (p = 0.91) or severe stenosis patients (p = 0.42).

Conclusion

There is no evidence to suggest that higher Lipoprotein(a) leads to increased myocardial midwall or infarction pattern fibrosis in patients with aortic stenosis.

Comparison of the effects of fibrates versus statins on plasma lipoprotein(a) concentrations: a systematic review and meta-analysis of head-to-head randomized controlled trials

BACKGROUND

Raised plasma lipoprotein(a) (Lp(a)) concentration is an independent and causal risk factor for atherosclerotic cardiovascular disease. Several types of pharmacological approaches are under evaluation for their potential to reduce plasma Lp(a) levels. There is suggestive evidence that statins and fibrates, two frequently employed lipid-lowering drugs, can lower plasma Lp(a). The present study aims to compare the efficacy of fibrates and statins in reducing plasma concentrations of Lp(a) using a meta-analysis of randomized head-to-head trials.

METHODS

Medline and Scopus databases were searched to identify randomized head-to-head comparative trials investigating the efficacy of fibrates versus statins in reducing plasma Lp(a) levels. Meta-analysis was performed using a random-effects model, with inverse variance weighted mean differences (WMDs) and 95% confidence intervals (CIs) as summary statistics. The impact of putative confounders on the estimated effect size was explored using random effects meta-regression.

RESULTS

Sixteen head-to-head comparative trials with a total of 1388 subjects met the eligibility criteria and were selected for this meta-analysis. Meta-analysis revealed a significantly greater effect of fibrates versus statins in reducing plasma Lp(a) concentrations (WMD, -2.70 mg/dL; 95% CI, -4.56 to -0.84; P = 0.004). Combination therapy with fibrates and statins had a significantly greater effect compared with statin monotherapy (WMD, -1.60 mg/dL; 95% CI, -2.93 to -0.26; P = 0.019) but not fibrate monotherapy (WMD, -1.76 mg/dL; 95% CI, -5.44 to +1.92; P = 0.349) in reducing plasma Lp(a) concentrations. The impact of fibrates versus statins in reducing plasma Lp(a) concentrations was not found to be significantly associated with treatment duration (P = 0.788).

CONCLUSIONS

Fibrates have a significantly greater effect in reducing plasma Lp(a) concentrations than statins. Addition of fibrates to statins can enhance the Lp(a)-lowering effect of statins.

Evidence-based assessment of lipoprotein(a) as a risk biomarker for cardiovascular diseases - Some answers and still many questions

The present article is aimed at outlining the current state of knowledge regarding the clinical value of lipoprotein(a) (Lp(a)) as a marker of cardiovascular disease (CVD) risk by summarizing the results of recent clinical studies, meta-analyses and systematic reviews. The literature supports the predictive value of Lp(a) on CVD outcomes, although the effect size is modest. Lp(a) would also appear to have an effect on cerebrovascular outcomes, however the effect appears even smaller than that for CVD outcomes. Consideration of apolipoprotein(a) (apo(a)) isoforms and LPA genetics in relation to the simple assessment of Lp(a) concentration may enhance clinical practice in vascular medicine. We also describe recent advances in Lp(a) research (including therapies) and highlight areas where further research is needed such as the measurement of Lp(a) and its involvement in additional pathophysiological processes.

Impact of L-carnitine on plasma lipoprotein(a) concentrations: A systematic review and meta-analysis of randomized controlled trials

We aimed to assess the impact of L-carnitine on plasma Lp(a) concentrations through systematic review and meta-analysis of available RCTs. The literature search included selected databases up to 31^st January 2015. Meta-analysis was performed using fixed-effects or random-effect model according to I² statistic. Effect sizes were expressed as weighted mean difference (WMD) and 95% confidence interval (CI). The meta-analysis showed a significant reduction of Lp(a) levels following L-carnitine supplementation (WMD: −8.82 mg/dL, 95% CI: −10.09, −7.55, p < 0.001). When the studies were categorized according to the route of administration, a significant reduction in plasma Lp(a) concentration was observed with oral (WMD: −9.00 mg/dL, 95% CI: −10.29, −7.72, p < 0.001) but not intravenous L-carnitine (WMD: −2.91 mg/dL, 95% CI: −10.22, 4.41, p = 0.436). The results of the meta-regression analysis showed that the pooled estimate is independent of L-carnitine dose (slope: −0.30; 95% CI: −4.19, 3.59; p = 0.878) and duration of therapy (slope: 0.18; 95% CI: −0.22, 0.59; p = 0.374). In conclusion, the meta-analysis suggests a significant Lp(a) lowering by oral L-carnitine supplementation. Taking into account the limited number of available Lp(a)-targeted drugs, L-carnitine might be an effective alternative to effectively reduce Lp(a). Prospective outcome trials will be required to fully elucidate the clinical value and safety of oral L-carnitine supplementation.

Lipoprotein(a): Its relevance to the pediatric population

Lipoprotein(a) (Lp(a)) is a highly atherogenic and heterogeneous lipoprotein that is inherited in an autosomal codominant trait. A unique aspect of this lipoprotein is that it is fully expressed by the first or second year of life in children, a pattern that is distinctly different from other lipoproteins, which typically only reach adult levels after adolescence. Despite decades of research, Lp(a) metabolism is still poorly understood but what is abundantly clear is that it is an independent risk factor for atherosclerotic cardiovascular disease (ASCVD). The Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents does not recommend measuring Lp(a) levels as part of routine screening except in youth with an ischemic or hemorrhagic stroke or youth with a parental history of ASCVD not explained by classical risk factors. One of the reasons that both the pediatric and adult guidelines fail to include this lipoprotein as part of routine lipid screening is the absence of data to show that lowering Lp(a) will reduce current or future ASCVD risk independently of low-density lipoprotein cholesterol (LDL-C) lowering. The cholesterol carried by Lp(a) is included in the low-density lipoprotein cholesterol measurement, but a separate test is used to measure the lipoprotein mass and/or cholesterol carried only by Lp(a). Because levels seem to be largely under genetic control, studies of lifestyle modification have been inconclusive although one study in obese children showed a decrease in the Lp(a) level comparable with the favorable effect on other lipids. The most compelling data regarding the importance of Lp(a) in the pediatric population are the increased risk associated with arterial ischemic stroke, a risk that is comparable with that associated with antiphospholipid antibodies or protein C deficiency. Although no specific pharmaceutical treatments are recommended to lower Lp(a) levels in youth, it is vitally important to educate youth and their parents about the excessive risk associated with this lipoprotein and the need to avoid the acquisition of other lifestyle-related risk factors such as smoking, excess weight, and physical inactivity to preserve more ideal cardiovascular health in adulthood.

Elevated oxidative stress among coronary artery disease patients on statin therapy: A cross sectional study

BACKGROUND

Statins are a major group of drugs that reduces LDL-C levels, which are proven to have other beneficial effects such as preventing coronary events. The objective of this study was to evaluate oxidative stress and select novel coronary artery disease risk factors among coronary artery disease patients on statins.

METHODS

In this observational, cross-sectional study, we compared total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, apolipoprotein B, lipoprotein (a), homocysteine, reduced glutathione, glutathione peroxidase, superoxide dismutase, ascorbic acid, malondialdehyde and oxidized LDL among male coronary artery disease patients on statin therapy (group 2, n = 151) with sex-matched, diabetic patients (group 3, n = 80) as well as healthy controls (group 1, n = 84).

RESULTS

Total cholesterol, triglycerides, HDL-cholesterol and LDL-cholesterol were significantly lower among subjects of group 2 compared to other two groups. The novel risk factors studied did not differ significantly between groups, except for a higher homocysteine level among group 2 subjects compared to the other two groups. Elevated oxidative stress, indicated by lower reduced glutathione, glutathione peroxidase, and ascorbic acid as well as higher malondialdehyde and oxidized LDL was observed among group 2 subjects. Triglycerides, HDL-cholesterol, ascorbic acid and malondialdehyde were found to be independent predictors for coronary artery disease among this study population.

CONCLUSIONS

Though coronary artery disease subjects had healthy lipid profile, oxidative stress, a recognized risk factor for coronary events, was still elevated among this patient group. Novel risk factors were not found to be major predictors for coronary artery disease among the study subjects.

IL-6 blockade by monoclonal antibodies inhibits apolipoprotein (a) expression and lipoprotein (a) synthesis in humans

Lipoprotein (a) [Lp(a)] is a highly atherogenic lipid particle. Although earlier reports suggested that Lp(a) levels are mostly determined by genetic factors, several recent studies have revealed that Lp(a) induction is also caused by chronic inflammation. Therefore, we aimed to examine whether cytokine blockade by monoclonal antibodies may inhibit Lp(a) metabolism. We found that interleukin 6 (IL-6) blockade by tocilizumab (TCZ) reduced Lp(a) while TNF-α-inhibition by adalimumab in humans had no effect. The specificity of IL-6 in regulating Lp(a) was further demonstrated by serological measurements of human subjects (n = 1,153) revealing that Lp(a) levels are increased in individuals with elevated serum IL-6. Transcriptomic analysis of human liver biopsies (n = 57) revealed typical IL-6 response genes being correlated with the LPA gene expression in vivo. On a molecular level, we found that TCZ inhibited IL-6-induced LPA mRNA and protein expression in human hepatocytes. Furthermore, examination of IL-6-responsive signal transducer and activator of transcription 3 binding sites within the LPA promoter by reporter gene assays, promoter deletion experiments, and electrophoretic mobility shift assay analysis showed that the Lp(a)-lowering effect of TCZ is specifically mediated via a responsive element at -46 to -40. Therefore, IL-6 blockade might be a potential therapeutic option to treat elevated Lp(a) serum concentrations in humans and might be a noninvasive alternative to lipid apheresis in the future.

New therapies targeting apoB metabolism for high-risk patients with inherited dyslipidaemias: what can the clinician expect?

Apolipoprotein B (apoB) has a key role in the assembly and secretion of very low-density lipoprotein (VLDL) from the liver. Plasma apoB concentration affects the number of circulating atherogenic particles, and serves as an independent predictor of the risk of atherosclerotic cardiovascular disease. While statins are the most potent apoB-lowering agents currently prescribed, their efficacy in achieving therapeutic targets for low-density lipoprotein cholesterol (LDL-C) in high-risk patients, such as those with familial hypercholesterolaemia (FH), is limited. Resistance and intolerance to statins also occurs in a significant number of patients, necessitating new types of lipid-lowering therapies. Monoclonal antibodies against proprotein convertase subtilisin/kexin type 9 (PCSK9; AMG 145 and REGN727), a sequence-specific antisense oligonucleotide against apoB mRNA (mipomersen) and a synthetic inhibitor of microsomal triglyceride transfer protein (MTTP; lomitapide) have been tested in phase III clinical trials, particularly in patients with FH. The trials demonstrated the efficacy of these agents in lowering apoB, LDL-C, non-high-density lipoprotein cholesterol and lipoprotein(a) by 32-55 %, 37-66 %, 38-61 % and 22-50 % (AMG 145), 21-68 %, 29-72 %, 16-60 % and 8-36 % (REGN727), 16-71 %, 15-71 %, 12-66 % and 23-49 % (mipomersen) and 24-55 %, 25-51 %, 27-50 % and 15-19 % (lomitapide), respectively. Monoclonal antibodies against PCSK9 have an excellent safety profile and may be indicated not only in heterozygous FH, but also in statin-intolerant patients and those with other inherited dyslipidemias, such as familial combined hyperlipidaemia and familial elevation in Lp(a). Mipomersen and lomitapide increase hepatic fat content and are at present indicated for treating adult patients with homozygous FH alone.

Plasma lipoprotein(a) levels in patients with slow coronary flow

Introduction

Slow coronary flow (SCF) is a microvascular disorder characterized by delayed opacification of coronary vessels with normal coronary angiogram. It may be due to endothelial dysfunction and diffuse atherosclerosis. Lipoprotein(a) [Lp(a)] is related to cardiovascular events. Plasma Lp(a) levels have not been studied previously in SCF patients.

Aim

We investigated plasma Lp(a) and fibrinogen levels, and their relation to coronary flow rate in patients with SCF.

Material and methods

This cross-sectional study included 50 patients with SCF and 30 age- and sex-matched controls who had normal coronary arteries and normal flow. Coronary flow rates of patients and controls were counted with the thrombolysis in myocardial infarction (TIMI) frame count. Plasma Lp(a) and fibrinogen levels were measured in SCF patients and controls, with routine biochemical tests.

Results

There were no significant differences between the two groups with respect to plasma Lp(a) (21 mg/dl vs. 14 mg/dl, p = 0.11) and fibrinogen (278 mg/dl vs. 291 mg/dl, p = 0.48) levels. The TIMI frame count was not correlated with plasma Lp(a) (r = 0.13, p = 0.25) or fibrinogen (r = –0.14, p = 0.28) levels.

Conclusions

Our results show that there is no significant association between SCF and Lp(a) and fibrinogen levels.

Lipoprotein(a): a promising marker for residual cardiovascular risk assessment

Atherosclerotic cardiovascular diseases (CVD) are still the leading cause of morbidity and mortality worldwide, although optimal medical therapy has been prescribed for primary and secondary preventions. Residual cardiovascular risk for some population groups is still considerably high although target low density lipoprotein-cholesterol (LDL-C) level has been achieved. During the past few decades, compelling pieces of evidence from clinical trials and meta-analyses consistently illustrate that lipoprotein(a) (Lp(a)) is a significant risk factor for atherosclerosis and CVD due to its proatherogenic and prothrombotic features. However, the lack of effective medication for Lp(a) reduction significantly hampers randomized, prospective, and controlled trials conducting. Based on previous findings, for patients with LDL-C in normal range, Lp(a) may be a useful marker for identifying and evaluating the residual cardiovascular risk, and aggressively lowering LDL-C level than current guidelines' recommendation may be reasonable for patients with particularly high Lp(a) level.

Vascular Access versus the Effect of Statins on Inflammation and Fibrinolysis in Renal Dialysis Patients

Purpose

The aim of this work was to assess the effect of statin therapy on inflammatory and fibrinolytic/endothelial (dys)function markers in end-stage renal disease (ESRD) patients under hemodialysis (HD), according to the type of vascular access.

Methods

This transversal study includes 191 ESRD patients under regular HD, divided into four groups according to vascular access and statin therapy: 87 patients with arteriovenous fistula (AVF) and no statins (AVF-NS), 61 with AVF and statins (AVF-S), 27 with central venous dialysis catheter (CVC) and no statins (CVC-NS) and 16 with CVC and statins (CVC-S). The basic lipid profile and fibrinolytic/endothelial cell function markers were assessed.

Results

Patients with CVC presented significantly higher levels of D-dimers compared with AVF groups. CVC-NS patients also presented the highest IL-6 values, which were significantly higher than those presented by CVC-S patients. AVF-S patients presented significantly higher t-PA and PAI-1 values and lower adiponectin levels compared with AVF-NS.

Conclusions

Our results demonstrate that patients with CVC, particularly those not under statin therapy, present a higher production and turnover of fibrin. We also found that statin therapy decreases inflammation in CVC patients but is associated with a reduction of adiponectin and increased endothelial function marker levels in AVF patients.

Lipoprotein(a): Cellular Effects and Molecular Mechanisms

Lipoprotein(a) (Lp(a)) is an independent risk factor for the development of cardiovascular disease (CVD). Indeed, individuals with plasma concentrations >20 mg/dL carry a 2-fold increased risk of developing CVD, accounting for ~25% of the population. Circulating levels of Lp(a) are remarkably resistant to common lipid lowering therapies, and there are currently no robust treatments available for reduction of Lp(a) apart from plasma apheresis, which is costly and labour intensive. The Lp(a) molecule is composed of two parts, an LDL/apoB-100 core and a unique glycoprotein, apolipoprotein(a) (apo(a)), both of which can interact with components of the coagulation cascade, inflammatory pathways, and cells of the blood vessel wall (smooth muscle cells (SMC) and endothelial cells (EC)). Therefore, it is of key importance to determine the molecular pathways by which Lp(a) exerts its influence on the vascular system in order to design therapeutics to target its cellular effects. This paper will summarise the role of Lp(a) in modulating cell behaviour in all aspects of the vascular system including platelets, monocytes, SMC, and EC.

Nicotinic acid inhibits hepatic APOA gene expression: studies in humans and in transgenic mice

Elevated plasma lipoprotein(a) (LPA) levels are recognized as an independent risk factor for cardiovascular diseases. Our knowledge on LPA metabolism is incomplete, which makes it difficult to develop LPA-lowering medications. Nicotinic acid (NA) is the main drug recommended for the treatment of patients with increased plasma LPA concentrations. The mechanism of NA in lowering LPA is virtually unknown. To study this mechanism, we treated transgenic (tg) APOA mice with NA and measured plasma APOA and hepatic mRNA levels. In addition, mouse and human primary hepatocytes were incubated with NA, and the expression of APOA was followed. Feeding 1% NA reduced plasma APOA and hepatic expression of APOA in tg-APOA mice. Experiments with cultured human and mouse primary hepatocytes in addition to reporter assays performed in HepG2 cells revealed that NA suppresses APOA transcription. The region between -1446 and -857 of the human APOA promoter harboring several cAMP response element binding sites conferred the negative effect of NA. In accordance, cAMP stimulated APOA transcription, and NA reduced hepatic cAMP levels. It is suggested that cAMP signaling might be involved in reducing APOA transcription, which leads to the lowering of plasma LPA.