Relationship Between Low-Density Lipoprotein Cholesterol and Lipoprotein(a) Lowering in Response to PCSK9 Inhibition With Evolocumab

New cardiovascular disease markers in patients with familial hypercholesterolemia carriers of genetic variants

Objectives

Familial hypercholesterolemia (FH) is an autosomal dominant genetic disease characterized by elevated levels of low-density lipoprotein cholesterol (LDLc). The early diagnosis of FH can reduce unfavorable outcomes in this population, but genetic study is not available in all populations. This study aimed to evaluate new cardiovascular plasma markers (GDF-15, CXCL16, FABP3, FABP4, LIGHT, sCD14, ucMGP), as well as Lp(a) levels, in individuals genetically characterized for FH, classified according to treatment with statins.

Methods

Sequencing was performed by next generation sequencing (NGS) for 17 ICs and by the Sanger method for 120 relatives. Lp(a) was measured by turbidimetry and the other cardiovascular markers by the multiplex method for Luminex®. Statistical analyses were performed using the R Platform version 4.2.2 program.

Results

86 individuals carrying FH genetic variants and 51 non-carrier family members were identified. Lp(a) showed higher levels in the group with variants and was correlated to LDLc levels. FABP3 levels were higher in the group carrying variants using statins compared to the group without statins. The non-carrier group using statins showed higher levels of FABP4 compared to the carrier group using statins. The markers GDF-15, CXCL16, LGHT, sCD14 and ucMGP did not show a significant difference between groups, but GDF-15 and sCD14 were correlated to LDLc levels.

Conclusions

Lp(a) and the new markers FABP3 e FABP4 are associated with FH, their levels are modulated by the use of statins, and they could be potential markers to assess the disease when genetic testing is not available.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-024-01537-w.

Novel therapeutic agents for cardiometabolic risk mitigation in heart transplant recipients

Heart transplant (HT) recipients experience high rates of cardiometabolic disease. Novel therapies targeting hyperlipidemia, diabetes, and obesity, including proprotein convertase subtilisin/kexin inhibitors, sodium-glucose cotransporter-2 inhibitors, and glucagon-like peptide-1 agonists, are increasingly used for cardiometabolic risk mitigation in the general population. However, limited data exist to support the use of these agents in patients who have undergone heart transplantation. Herein, we describe the mechanisms of action and emerging evidence supporting the use of novel pharmacologic agents in the post-HT setting for cardiometabolic risk mitigation and review evidence supporting their ability to modulate immune pathways associated with atherogenesis, epicardial adipose tissue, and coronary allograft vasculopathy.

Association between lipoprotein(a) and coronary heart disease risk in type 2 diabetes mellitus and evaluation of statin treatment effects

OBJECTIVE

The aim of this study was to investigate the association between lipoprotein(a) and coronary heart disease risk in type 2 diabetes mellitus patients and evaluate the effectiveness of statin therapy.

METHODS

This retrospective analysis included 120 patients diagnosed with type 2 diabetes mellitus. Of these, 90 patients diagnosed with coronary heart disease via coronary angiography received rosuvastatin treatment for over 6 months. The remaining 30 patients exhibited no coronary heart disease or other diabetic macrovascular complications and had not received any lipid-lowering treatment. Patients with type 2 diabetes mellitus and coronary heart disease were categorized into two groups based on the severity of coronary lesions. Baseline characteristics and blood lipid data were compared among groups. Logistic regression analysis was employed to investigate the association between lipoprotein(a) and coronary heart disease risk in type 2 diabetes mellitus patients. Receiver operating characteristic curves were utilized to evaluate the diagnostic value of lipoprotein(a) for coronary heart disease.

RESULTS

Compared with the control group, lipoprotein(a) levers were higher in both the mild and severe groups. Logistic regression analysis demonstrated that lipoprotein(a) is independently associated with the risk of coronary heart disease in type 2 diabetes mellitus patients. The area under the receiver operating characteristic curve for lipoprotein(a) was 0.729. When lipoprotein(a) was 97.5 mg/L, the diagnosis of coronary heart disease had high sensitivity and specificity. After statin therapy, high-density lipoprotein cholesterol and apolipoprotein A levels increased, while other lipid parameters decreased. However, the lipoprotein(a) level decrease was not statistically significant.

CONCLUSION

Lipoprotein(a) is an independent risk factor for coronary heart disease in type 2 diabetes mellitus patients. Lipid-lowering therapy with statins alone cannot reduce lipoprotein(a) levels.

Impact of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors on Lipoprotein(a): A Meta-Analysis and Meta-Regression of Randomized Controlled Trials

Background

Lipoprotein(a) [Lp(a)] has been independently associated with increased cardiovascular risk.

Objectives

The authors examined the effect of monoclonal antibody proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9is) on plasma Lp(a) levels across multiple trials.

Methods

Studies were retrieved comparing the effect of PCSK9i vs placebo on Lp(a) levels. The primary outcome was percent change in Lp(a) levels. Factors associated with the treatment effect were determined by meta-regression analysis. Subgroup analyses were done to explore potential treatment effect differences.

Results

PCSK9i reduced Lp(a) levels on average of -27% (95% CI: -29.8% to -24.1%, P < 0.001). Factors associated with the treatment effect included mean percent change in low-density lipoprotein cholesterol (P = 0.003, beta coefficient 0.34, 95% CI: 0.11-0.57, tau2 = 94.8, R2 = 11.82) and apolipoprotein B (P < 0.002, beta coefficient 0.4, 95% CI: 0.14-0.64, tau2 = 93.68, R2 = 11.86). Subgroup analyses revealed consistent treatment effect amongst comparators vs placebo: -27.69% (95% CI: -30.85% to -24.54%, P < 0.001), vs ezetimibe: -24.0% (95% CI: -29.95% to -18.01%, P < 0.001), type of PCSK9i, evolocumab: -29.35% (95% CI: -33.56% to -25.14%, P < 0.001) vs alirocumab: -24.50% (95% CI: -27.96% to -21.04%, P < 0.001), and presence of familial hypercholesterolemia: -25.63% (95% CI: -31.96% to -19.30%, P < 0.001 vs no familial hypercholesterolemia: -27.22%; 95% CI: -30.34% to -24.09%, P < 0.001). Varying treatment effects were noted in the duration of treatment (12 weeks or shorter: -32.43% [95% CI: -36.63% to -28.23% vs >12 weeks: -22.31%] [95% CI: -25.13% to -19.49%, P < 0.001]), P interaction < 0.01.

Conclusions

PCSK9is reduce Lp(a) levels by an average of 27%. Mean percent change in low-density lipoprotein cholesterol and apolipoprotein B were associated with treatment effect.

Efficacy and Safety of Bempedoic Acid in Patients with High Cardiovascular Risk: An Update

Statins play a significant role in the prevention of cardiovascular (CV) diseases (CVDs); however, non-adherence with statin treatment or statin intolerance (mainly attributed to muscleassociated side effects) is not uncommon. New agents such as bempedoic acid (BA) can provide more treatment options. BA is administered orally, once daily, at a dose of 180 mg in current clinical practice. It can decrease circulating low-density lipoprotein cholesterol (LDL-C) levels by nearly 30% as monotherapy or by 20% as an add-on to statins. CV outcome studies have shown that BA decreases major adverse CV event risk in patients with established CVD or high CV risk by 13%. When patients with high CV risk were analyzed alone, the risk reduction was 30%. Its side effects include a rise in serum uric acid levels and liver enzyme activity, whereas it does not increase diabetes risk as statins do. BA can be used as adjunctive therapy to statins in patients at high CV risk in whom lipid targets cannot be achieved or as an alternative to statins in patients with statin intolerance.

Sex X Time Interactions in Lp(a) and LDL-C Response to Evolocumab

The aim of this study was to evaluate whether there were significant sex x time interactions in lipoprotein(a) (Lp(a)) and low-density lipoprotein cholesterol (LDL-C) response to treatment with the Proprotein Convertase Subtilisin/Kexin type 9 inhibitor (PCSK9i) Evolocumab, in a real-life clinical setting. For this purpose, we pooled data from 176 outpatients (Men: 93; Women: 83) clinically evaluated at baseline and every six months after starting Evolocumab. Individuals who had been on PCSK9i for less than 30 months and nonadherent patients were excluded from the analysis. Over time, absolute values of Lp(a) plasma concentrations significantly decreased in the entire cohort (p-value < 0.001) and by sex (p-value < 0.001 in men and p-value = 0.002 in and women). However, there were no sex-related significant differences. Absolute plasma concentrations of LDL-C significantly decreased over time in the entire cohort and by sex (p-value < 0.001 always), with greater improvements in men compared to women. The sex x time interaction was statistically significant in LDL-C (all p-values < 0.05), while absolute changes in Lp(a) were not influenced by either sex or time (all p-value > 0.05). Our data partially reinforce the presence of differences in response to treatment to PCSK9i between men and women and are essential to gain a better understanding of the relationship between LDL-C and Lp(a) lowering in response to PCSK9i. Further research will clarify whether these sex-related significant differences translate into a meaningful difference in the long-term risk of ASCVD.

Lipoprotein(a) in patients with breast cancer after chemotherapy: exploring potential strategies for cardioprotection

Developments in neoadjuvant and adjuvant chemotherapy (CHT) have led to an increase in the number of breast cancer survivors. The determination of an appropriate follow-up for these patients is of increasing importance. Deaths due to cardiovascular disease (CVD) are an important part of mortality in patients with breast cancer.This review suggests that chemotherapeutic agents may influence lipoprotein(a) (Lp(a)) concentrations in breast cancer survivors after CHT based on many convincing evidence from epidemiologic and observational researches. Usually, the higher the Lp(a) concentration, the higher the median risk of developing CVD. However, more clinical trial results are needed in the future to provide clear evidence of a possible causal relationship. This review also discuss the existing and emerging therapies for lowering Lp(a) concentrations in the clinical setting. Hormone replacement therapy, statins, proprotein convertase subtilisin/kexin-type 9 (PCSK9) inhibitors, Antisense oligonucleotides, small interfering RNA, etc. may reduce circulating Lp(a) or decrease the incidence of CVD.

Novel Pharmacological Therapies for the Management of Hyperlipoproteinemia(a)

Lipoprotein(a) [Lp(a)] is a well-established risk factor for cardiovascular disease, predisposing to major cardiovascular events, including coronary heart disease, stroke, aortic valve calcification and abdominal aortic aneurysm. Lp(a) is differentiated from other lipoprotein molecules through apolipoprotein(a), which possesses atherogenic and antithrombolytic properties attributed to its structure. Lp(a) levels are mostly genetically predetermined and influenced by the size of LPA gene variants, with smaller isoforms resulting in a greater synthesis rate of apo(a) and, ultimately, elevated Lp(a) levels. As a result, serum Lp(a) levels may highly vary from extremely low to extremely high. Hyperlipoproteinemia(a) is defined as Lp(a) levels > 30 mg/dL in the US and >50 mg/dL in Europe. Because of its association with CVD, Lp(a) levels should be measured at least once a lifetime in adults. The ultimate goal is to identify individuals with increased risk of CVD and intervene accordingly. Traditional pharmacological interventions like niacin, statins, ezetimibe, aspirin, PCSK-9 inhibitors, mipomersen, estrogens and CETP inhibitors have not yet yielded satisfactory results. The mean Lp(a) reduction, if any, is barely 50% for all agents, with statins increasing Lp(a) levels, whereas a reduction of 80-90% appears to be required to achieve a significant decrease in major cardiovascular events. Novel RNA-interfering agents that specifically target hepatocytes are aimed in this direction. Pelacarsen is an antisense oligonucleotide, while olpasiran, LY3819469 and SLN360 are small interfering RNAs, all conjugated with a N-acetylgalactosamine molecule. Their ultimate objective is to genetically silence LPA, reduce apo(a) production and lower serum Lp(a) levels. Evidence thus so far demonstrates that monthly subcutaneous administration of a single dose yields optimal results with persisting substantial reductions in Lp(a) levels, potentially enhancing CVD risk reduction. The Lp(a) reduction achieved with novel RNA agents may exceed 95%. The results of ongoing and future clinical trials are eagerly anticipated, and it is hoped that guidelines for the tailored management of Lp(a) levels with these novel agents may not be far off.

Proprotein Convertase Subtilisin/Kexin Type 9 Inhibition: The Big Step Forward in Lipid Control

The breakthrough discovery of proprotein convertase subtilisin/kexin type 9 (PCSK9) 20 years ago revolutionised the current understanding of cholesterol homeostasis. Genetic studies have shown that gain-of-function mutations in PCSK9 lead to elevated LDL cholesterol and increased risk of atherosclerotic cardiovascular disease, while loss-of-function mutations in PCSK9 result in lifelong low levels of circulating LDL cholesterol and dramatic reduction in atherosclerotic cardiovascular disease. Therapies inhibiting PCSK9 lead to a higher density of LDL receptor on the surface of hepatocytes, resulting in greater ability to clear circulating LDL. Thus far, randomised controlled trials have shown that subcutaneous fully human monoclonal antibodies targeting PCSK9, evolocumab and alirocumab, and PCSK9 silencing with inclisiran result in drastic reductions in LDL cholesterol. Additionally, several novel strategies to target PCSK9 are in development, including oral antibody, gene silencing, DNA base editing and vaccine therapies. This review highlights the efficacy, safety and clinical use of these various approaches in PCSK9 inhibition.

Elevated Lp(a) Levels Correlate with Severe and Multiple Coronary Artery Stenotic Lesions

Backgrounds and Aims

The role of Lipoprotein(a) (Lp(a)) in increasing the risk of cardiovascular diseases is reported in several populations. The aim of this study is to investigate the correlation of high Lp(a) levels with the degree of coronary artery stenosis.

Methods

Two hundred and sixty-eight patients were enrolled for this study. Patients who underwent coronary artery angiography and who had Lp(a) measurements available were included in this study. Binomial logistic regressions were applied to investigate the association between Lp(a) and stenosis in the four major coronary arteries. The effect of LDL and HDL Cholesterol on modulating the association of Lp(a) with coronary artery disease (CAD) was also evaluated. Multinomial regression analysis was applied to assess the association of Lp(a) with the different degrees of stenosis in the four major coronary arteries.

Results

Our analyses showed that Lp(a) is a risk factor for CAD and this risk is significantly apparent in patients with HDL-cholesterol ≥35 mg/dL and in non-obese patients. A large proportion of the study patients with elevated Lp(a) levels had CAD even when exhibiting high HDL serum levels. Increased HDL with low Lp(a) serum levels were the least correlated with stenosis. A significantly higher levels of Lp(a) were found in patients with >50% stenosis in at least two major coronary vessels arguing for pronounced and multiple stenotic lesions. Finally, the derived variant (rs1084651) of the LPA gene was significantly associated with CAD.

Conclusion

Our study highlights the importance of Lp(a) levels as an independent biological marker of severe and multiple coronary artery stenosis.

Inter-Individual Variability in Lipid Response: A Narrative Review

Lipid-lowering guidelines emphasize shared decision-making between clinicians and patients, resulting in patients anticipating the degree of response from diet or drug therapy. Challenging for physicians is understanding the sources of variability complicating their management decisions, which include non-adherence, genetic considerations, additional lipid parameters including lipoprotein (a) levels, and rare systemic responses limiting benefits that result in non-responsiveness to monoclonal antibody injection. In this narrative review, we focus on the variability of low-density lipoprotein cholesterol (LDL-C) response to guideline-directed interventions such as statins, ezetimibe, bile acid sequestrants, fibrates, proprotein/convertase subtilisin-kexin type 9 inhibitors, and LDL-C-lowering diets. We hypothesize that the variability in individual lipid responses is multifactorial. We provide an illustrative model with a check list that can be used to identify factors that may be present in the individual patient.

Low circulating PCSK9 levels in LPL homozygous children with chylomicronemia syndrome in a syrian refugee family in Lebanon

Familial chylomicronemia syndrome is a rare autosomal recessive disorder of lipoprotein metabolism characterized by the presence of chylomicrons in fasting plasma and an important increase in plasma triglycerides (TG) levels that can exceed 22.58 mmol/l. The disease is associated with recurrent episodes of abdominal pain and pancreatitis, eruptive cutaneous xanthomatosis, lipemia retinalis, and hepatosplenomegaly. A consanguineous Syrian family who migrated to Lebanon was referred to our laboratory after perceiving familial chylomicronemia syndrome in two children. The LPL and PCSK9 genes were sequenced and plasma PCSK9 levels were measured. Sanger sequencing of the LPL gene revealed the presence of the p.(Val227Phe) pathogenic variant in exon 5 at the homozygous state in the two affected children, and at the heterozygous state in the other recruited family members. Interestingly, PCSK9 levels in homozygous carriers of the p.(Val227Phe) were ≈50% lower than those in heterozygous carriers of the variant (p-value = 0.13) and ranged between the 5th and the 7.5th percentile of PCSK9 levels in a sample of Lebanese children of approximately the same age group. Moreover, this is the first reported case of individuals carrying simultaneously an LPL pathogenic variant and PCSK9 variants, the L10 and L11 leucine insertion, which can lower and raise low-density lipoprotein cholesterol (LDL-C) levels respectively. TG levels fluctuated concomitantly between the two children, were especially high following the migration from a country to another, and were reduced under a low-fat diet. This case is crucial to raise public awareness on the risks of consanguineous marriages to decrease the emergence of inherited autosomal recessive diseases. It also highlights the importance of the early diagnosis and management of these diseases to prevent serious complications, such as recurrent pancreatitis in the case of familial hyperchylomicronemia.

A method for lipoprotein (a) Isolation from a small volume of plasma with applications for clinical research

High levels of circulating Lipoprotein (a) [Lp(a)] are an independent risk factor for CVD. One of the major limitations to investigating Lp(a) biology is the need for large volumes of plasma (4-10 mL) for its isolation. We developed an isolation technique requiring only 0.4 mL of plasma yielding an enriched Lp(a) fraction suitable for compositional and functional studies. We collected plasma from patients (n = 9) in EDTA presenting to our Center for Preventive Cardiology for CVD risk management and with circulating Lp(a) > 66 mg/dL. 0.4 mL of plasma was added to 90 µL of potassium bromide (1.33 g/mL) and subjected to our two-step density-gradient ultracentrifugation method. The first step separates VLDL and LDL from the Lp(a) and HDL fractions and the second step further separates VLDL from LDL and Lp(a) from HDL. Lp(a) is then dialyzed for up to 24 h in potassium phosphate buffer. We performed cholesterol gel electrophoresis, immunoblotting and LC-MS/MS proteomics on isolated lipoprotein fractions to confirm fraction enrichment. Functional studies including Lp(a)-dependent induction of macrophage gene expression and cholesterol efflux inhibition were performed on isolated Lp(a) to confirm its preserved bioactivity. Lp(a) yields (264 ± 82.3 µg/mL on average) correlated with Lp(a) plasma concentrations (r2 = 0.75; p < 0.01) and represented the relative distribution of circulating apo(a) isoforms. Proteomic analyses confirm lipoprotein fraction separation. Functional integrity was confirmed by the findings that isolated Lp(a) inhibited plasminogen-dependent cholesterol efflux in HEK293T cells expressing ABCA1 and increased expressions of Il1b, Nos2 and Ccl2. We developed a small-volume isolation technique for Lp(a) suited for a range of applications used in biomedical research. The use of this technique circumvents volume-dependent limitations and expands our ability to investigate the mysteries of this deleterious lipoprotein.

Apolipoproteins in vascular biology and atherosclerotic disease

Apolipoproteins are important structural components of plasma lipoproteins that influence vascular biology and atherosclerotic disease pathophysiology by regulating lipoprotein metabolism. Clinically important apolipoproteins related to lipid metabolism and atherogenesis include apolipoprotein B-100, apolipoprotein B-48, apolipoprotein A-I, apolipoprotein C-II, apolipoprotein C-III, apolipoprotein E and apolipoprotein(a). Apolipoprotein B-100 is the major structural component of VLDL, IDL, LDL and lipoprotein(a). Apolipoprotein B-48 is a truncated isoform of apolipoprotein B-100 that forms the backbone of chylomicrons. Apolipoprotein A-I provides the scaffolding for lipidation of HDL and has an important role in reverse cholesterol transport. Apolipoproteins C-II, apolipoprotein C-III and apolipoprotein E are involved in triglyceride-rich lipoprotein metabolism. Apolipoprotein(a) covalently binds to apolipoprotein B-100 to form lipoprotein(a). In this Review, we discuss the mechanisms by which these apolipoproteins regulate lipoprotein metabolism and thereby influence vascular biology and atherosclerotic disease. Advances in the understanding of apolipoprotein biology and their translation into therapeutic agents to reduce the risk of cardiovascular disease are also highlighted.

Value of repeated measurements of lipoprotein (a) to assess cardiovascular risk: a retrospective study

Background: High plasma concentrations of lipoprotein (a) [Lp(a)] are associated with an increased cardiovascular risk. Current guidelines recommend measurement of only a single Lp(a) in an individual's lifetime under specific circumstances to improve cardiovascular risk prediction. Accordingly, the question raised is the number of false positives and negatives missed through only a single measurement.Methods: All Lp(a) measurements between 2004 and March 2021 were retrieved from the laboratory database of the Erasme hospital. Only patients with repeated measurement were included. The first and subsequent Lp(a) measurement were compared. Two different cohorts were studied as a result of a change in Lp(a) determination methodology (n = 2049 and n = 309, respectively). The effects of a third Lp(a) measurement were assessed through binary analyses (n = 678). The 180 mg/dl (430 nmol/L) threshold recommended in the ESC guidelines was assessed first. Analysis was repeated for 100, 70 and 50 mg/dl thresholds of raised Lp(a) levels.Results: A low rate of false negatives (0.8%-1%) and false positives (0.6-0.3%) were revealed with two Lp(a) measurements. There was no difference in regards to the divergent Lp(a) thresholds nor the measurement of Lp(a) on two or three occasions.Conclusion: The present study showed Lp(a) determination to be reproducible. A single measurement is sufficient to assess if a patient exceeds various cut-off values of elevated Lp(a) levels.

Modern Approaches to Lower Lipoprotein(a) Concentrations and Consequences for Cardiovascular Diseases

Lipoprotein(a) (Lp(a)) is a low density lipoprotein particle that is associated with poor cardiovascular prognosis due to pro-atherogenic, pro-thrombotic, pro-inflammatory and pro-oxidative properties. Traditional lipid-lowering therapy does not provide a sufficient Lp(a) reduction. For PCSK9 inhibitors a small reduction of Lp(a) levels could be shown, which was associated with a reduction in cardiovascular events, independently of the effect on LDL cholesterol. Another option is inclisiran, for which no outcome data are available yet. Lipoprotein apheresis acutely and in the long run decreases Lp(a) levels and effectively improves cardiovascular prognosis in high-risk patients who cannot be satisfactorily treated with drugs. New drugs inhibiting the synthesis of apolipoprotein(a) (an antisense oligonucleotide (Pelacarsen) and two siRNA drugs) are studied. Unlike LDL-cholesterol, for Lp(a) no target value has been defined up to now. This overview presents data of modern capabilities of cardiovascular risk reduction by lowering Lp(a) level.

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

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

Efficacy evaluation of PCSK9 monoclonal antibody (Evolocumab) in combination with Rosuvastatin and Ezetimibe on cholesterol levels in patients with coronary heart disease (CHD): A retrospective analysis from a single center in China

BACKGROUND AND PURPOSE

Proprotein convertase subtilisin-kexin type 9(PCSK9) monoclonal antibody (Mab; Evolocumab) has been reported to inhibit low-density lipoprotein cholesterol (LDL-C) and Lipoprotein(a) [LP(a)] in coronary heart diseases (CHD) patients in America, Europe and Japan. However, little is known about the effect of Evolocumab in Chinese population. This retrospective study in Chinese CHD patients compared the efficacy without or with Evolocumab therapy added to the conventional treatment with a statin (Rosuvastatin) and a gut cholesterol absorption inhibitor (Ezetimibe).

METHODS

CHD patients from our hospital were divided into three therapeutic groups, A) the statin monotherapy group (10 mg Rosuvastatin every night); B) the statin/cholesterol absorption inhibitor group (10 mg Rosuvastatin and 10 mg Ezetimibe daily); and C) the triple therapy with PCSK9 Mab group (10 mg Rosuvastatin daily, 10 mg Ezetimibe daily, and 140 mg Evolocumab once 2 weeks). The plasma lipid data were collected at 0, 4, 12, and 24 Week(s). The Graphpad Prism 7 program was used to perform all the statistical analysis.

RESULTS

Out of 103 patients 91 were eligible for further evaluation with 31 in group A, 31 in group B, and 29 in group C. The plasma LDL-C levels were reduced only by 33.82% in the Rosuvastatin monotherapy group, 52.13% in the Rosuvastatin/Ezetimibe group, and 73.59% in the Evolocumab/Rosuvastatin/Ezetimibe group (P < 0.0001) at 24 weeks compared to the prior therapy levels. Neither the statin therapy alone (5.95%; P = 0.6), nor the double therapy (5.27%; P = 0.7) affected LP(a) levels. In contrast, addition of Evolocumab to the double therapy significantly decreased LP(a) level by 37.2% (P < 0.0001).

CONCLUSION

Addition of Evolocumab to the standard double therapy in Chinese CHD patients improved the efficacy in LDL-C reduction when compared to Rosuvastatin alone or in Rosuvastatin/Ezetimibe double therapy. Furthermore, the addition of Evolocumab lowered LP(a) level in Chinese CHD patients.

The size of apolipoprotein (a) is an independent determinant of the reduction in lipoprotein (a) induced by PCSK9 inhibitors

AIMS

Lipoprotein (a) [Lp(a)] is a lipoprotein species causatively associated with atherosclerosis. Unlike statins, PCSK9 inhibitors (PCSK9i) reduce Lp(a), but this reduction is highly variable. Levels of Lp(a) are chiefly governed by the size of its signature protein, apolipoprotein (a) [apo(a)]. Whether this parameter determines some of the reduction in Lp(a) induced by PCSK9i remains unknown. We aimed to investigate if the Lp(a) lowering efficacy of PCSK9i is modulated by the size of apo(a), which is genetically determined by the variable number of KIV domains present on that protein.

METHODS AND RESULTS

The levels of Lp(a) and the size of apo(a) were assessed in plasma samples from 268 patients before and after treatment with PCSK9i. Patients were recruited at the Outpatient Lipid Clinic of the Charité Hospital (Berlin) between 2015 and 2020. They were hypercholesterolemic at very high CVD risk with LDL-cholesterol levels above therapeutic targets despite maximally tolerated lipid-lowering therapy. Patients received either Alirocumab (75 or 150 mg) or Evolocumab (140 mg) every 2 weeks. Apo(a), apoB100, and apoE concentrations as well as apoE major isoforms were determined by liquid chromatography high-resolution mass spectrometry. Apo(a) isoforms sizes were determined by Western Blot. PCSK9i sharply reduced LDL-cholesterol (-57%), apoB100 (-47%) and Lp(a) (-36%). There was a positive correlation between the size of apo(a) and the relative reduction in Lp(a) induced by PCSK9i (r = 0.363, p = 0.0001). The strength of this association remained unaltered after adjustment for baseline Lp(a) levels and all other potential confounding factors. In patients with two detectable apo(a) isoforms, there was also a positive correlation between the size of apo(a) and the reduction in Lp(a), separately for the smaller (r = 0.350, p = 0.0001) and larger (r = 0.324, p = 0.0003) isoforms. The relative contribution of the larger isoform to the total concentration of apo(a) was reduced from 29% to 15% (p < 0.0001).

CONCLUSIONS

The size of apo(a) is an independent determinant of the response to PCSK9i. Each additional kringle domain is associated with a 3% additional reduction in Lp(a). This explains in part the variable efficacy of PCSK9i and allows to identify patients who will benefit most from these therapies in terms of Lp(a) lowering.

TRANSLATIONAL PERSPECTIVE

Unlike statins, PCSK9 inhibitors reduce the circulating levels of the highly atherogenic Lipoprotein (a). The underlying mechanism remains a matter of considerable debate. The size of apo(a), the signature protein of Lp(a), is extremely variable (300 to more than 800 kDa) and depends on its number of kringle domains. We now show that each increase in apo(a) size by one kringle domain is associated with a 3% additional reduction in Lp(a) following PCSK9i treatment and that apo(a) size polymorphism is an independent predictor of the reduction in Lp(a) induced by these drugs. In an era of personalized medicine, this allows to identify patients who will benefit most from PCSK9i in terms of Lp(a) lowering.

PCSK9 Antibody-based Treatment Strategies for Patients With Statin Intolerance

BACKGROUND

Statin intolerance refers to the inability of a patient to tolerate statin therapy, presenting muscle aches, pains, weakness and muscle inflammation. Thus, numerous patients are not treated with suitable statin-based therapy or take only very low doses. As a result, the desired decrease in low-density lipoprotein cholesterol (LDL-C) is not achieved, resulting in patients at a high risk for cardiovascular events, requiring an alternative lipid-lowering treatment. Common treatments manage to reduce the LDL-C level by up to 20%. Recently, new alternative treatment options have been proved to lower the LDL-C level by up to 70%. These treatment strategies are based on human monoclonal antibodies against protein convertase subtilisin/kexin 9 (PCSK9).

MATERIALS AND METHODS

Herein, we review the efficiency of anti-PCSK9 in treatment of hypercholesterolemic patients with statin intolerance. We focused on the use of PCSK9 inhibitors in statin-intolerant patients and we estimated the clinical results concerning the reduction of the mean LDL-C concentration and the side effects that were observed.

RESULTS

In the majority of cases, treatment strategy based on PCSK9 was successful and achieved the end-points.

CONCLUSION

PCSK9 inhibition can be considered as a treatment of option for lipid-lowering in statin-intolerant patients.

The association of lipoprotein(a) and intraplaque neovascularization in patients with carotid stenosis: a retrospective study

Background

Lipoprotein(a) is genetically determined and increasingly recognized as a major risk factor for arteriosclerotic cardiovascular disease. We examined whether plasma lipoprotein(a) concentrations were associated with intraplaque neovascularization (IPN) grade in patients with carotid stenosis and in terms of increasing plaque susceptibility to haemorrhage and rupture.

Methods

We included 85 patients diagnosed with carotid stenosis as confirmed using carotid ultrasound who were treated at Guangdong General Hospital. Baseline data, including demographics, comorbid conditions and carotid ultrasonography, were recorded. The IPN grade was determined using contrast-enhanced ultrasound through the movement of the microbubbles. Univariate and multivariate binary logistic regression analyses were used to evaluate the association between lipoprotein(a) and IPN grade, with stepwise adjustment for covariates including age, sex, comorbid conditions and statin therapy (model 1), total cholesterol, triglyceride, low-density lipoprotein cholesterol calculated by Friedwald's formula, high-density lipoprotein cholesterol, apolipoprotein A and apolipoprotein B (model 2), maximum plaque thickness and total carotid maximum plaque thickness, degree of carotid stenosis and internal carotid artery (ICA) occlusion (model 3).

Results

Lipoprotein(a) was a significant predictor of higher IPN grade in binary logistic regression before adjusting for other risk factors (odds ratio [OR] 1.238, 95% confidence interval [CI] (1.020, 1.503), P = 0.031). After adjusting for other risk factors, lipoprotein(a) still remained statistically significant in predicting IPN grade in all model. (Model 1: OR 1.333, 95% CI 1.074, 1.655, P = 0.009; Model 2: OR 1.321, 95% CI 1.059, 1.648, P = 0.014; Model 3: OR 1.305, 95% CI 1.045, 1.628, P = 0.019). Lp(a) ≥ 300 mg/L is also significantly related to IPN compare to < 300 mg/L (OR 2.828, 95% CI 1.055, 7.580, P = 0.039) as well as in model 1, while in model 2 and model 3 there are not significant difference.

Conclusions

Plasma lipoprotein(a) concentrations were found to be independently associated with higher IPN grade in patients with carotid stenosis. Lowering plasma lipoprotein(a) levels may result in plaque stabilization by avoiding IPN formation.

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

BACKGROUND

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

ANGPLT3 in cardio-metabolic disorders

Dyslipidemia is associated with numerous health problems that include the combination of insulin resistance, hypertension and obesity, which is always grouped together asmetabolic syndrome. Given that metabolic syndrome leads to a high mortality and poses serious risks to human health worldwide, it is vital to explore the mechanisms whereby dyslipidemia modulates the risk and the severity of cardio-metabolic disorders. Recently, a specific secretory protein family, named angiopoietin-like protein (ANGPTL), is considered as one of the significant biomarkers which facilitate the development of angiogenesis. Among the eight proteins of ANGPTL family, ANGPTL3 has been demonstrated as an essential modulator of lipid catabolism within circulation by inhibiting the activity of lipoprotein lipase (LPL) and endothelial lipase (EL). Consistent with these notions, mice with ANGPTL3 gene-deficiency presented reduced circulating levels of low density lipoprotein cholesterol (LDL-C) and lower risk of atherosclerosis. On the other hand, participants carrying homozygous loss-of function (LOF) mutation in ANGPTL3 gene also displayed lower circulating LDL-C levels and atherosclerotic risk. In the current review, we summarized the recent understanding of ANGPTL3 in controlling the risk and the development of dyslipidemia and its related cardio-metabolic disorders. Moreover, we also provided the perspectives which potentially suggested that ANGPTL3 could be considered as a promising target in treating metabolic syndrome.

Current Evidence and Future Directions of PCSK9 Inhibition

Recent scientific and therapeutic advances in proprotein convertase subtilisin kexin type 9 (PCSK9) inhibition have opened a chapter in the management of hypercholesterolemia, especially in patients who are inadequately controlled on or intolerant to statins. The two PCSK9 monoclonal antibodies, evolocumab and alirocumab, reduce LDL cholesterol by 60% and improve cardiovascular outcomes when taken in addition to statin therapy. More recently, inclisiran, a silencing RNA (siRNA) that inhibits translation of PCSK9 mRNA, demonstrated LDL cholesterol reduction by 45-50% with the advantage of dramatically reduced dose frequency. Other modes of PCSK9 inhibition include small molecule antagonists, vaccines, CRISPR gene editing, and antagonism at various steps of translation, and post-translational processing.

Effect of one-anastomosis gastric bypass on cardiovascular risk factors in patients with vitamin D deficiency and morbid obesity: A secondary analysis

BACKGROUND AND AIMS

Bariatric patients often suffer from vitamin D (VD) deficiency, and both, morbid obesity and VD deficiency, are related to an adverse effect on cardiovascular disease (CVD) risk. Therefore, we assessed the change of known CVD risk factors and its associations during the first 12 months following one-anastomosis gastric bypass (OAGB).

METHODS AND RESULTS

In this secondary analysis, CVD risk factors, medical history and anthropometric data were assessed in fifty VD deficient (25-hydroxy-vitamin D (25(OH)D) <75 nmol/l) patients, recruited for a randomized controlled trial of VD supplementation. Based on previous results regarding bone-mass loss and the association between VD and CVD risk, the study population was divided into patients with 25(OH)D ≥50 nmol/l (adequate VD group; AVD) and into those <50 nmol/l (inadequate VD group; IVD) at 6 and 12 months (T6/12) postoperatively. In the whole cohort, substantial remission rates for hypertension (38%), diabetes (30%), and dyslipidaemia (41%) and a significant reduction in CVD risk factors were observed at T12. Changes of insulin resistance markers were associated with changes of total body fat mass (TBF%), 25(OH)D, and ferritin. Moreover, significant differences in insulin resistance markers between AVD and IVD became evident at T12.

CONCLUSION

These findings show that OAGB leads to a significant reduction in CVD risk factors and amelioration of insulin resistance markers, which might be connected to reduced TBF%, change in 25(OH)D and ferritin levels, as an indicator for subclinical inflammation, and an adequate VD status. REGISTERED AT CLINICALTRIALS.GOV: (Identifier: NCT02092376) and EudraCT (Identifier: 2013-003546-16).

PCSK9 in Myocardial Infarction and Cardioprotection: Importance of Lipid Metabolism and Inflammation

Extensive evidence from epidemiologic, genetic, and clinical intervention studies has indisputably shown that elevated low-density lipoprotein cholesterol (LDL-C) concentrations play a central role in the pathophysiology of atherosclerotic cardiovascular disease. Apart from LDL-C, also triglycerides independently modulate cardiovascular risk. Reduction of proprotein convertase subtilisin/kexin type 9 (PCSK9) has emerged as a therapeutic target for reducing plasma LDL-C, but it is also associated with a reduction in triglyceride levels potentially through modulation of the expression of free fatty acid transporters. Preclinical data indicate that PCSK9 is up-regulated in the ischaemic heart and decreasing PCSK9 expression impacts on infarct size, post infarct inflammation and remodeling as well as cardiac dysfunction following ischaemia/reperfusion. Clinical data support that notion in that PCSK9 inhibition is associated with reductions in the incidence of myocardial infarction, stroke, and coronary revascularization and an improvement of endothelial function in subjects with increased cardiovascular risk. The aim of the current review is to summarize the current knowledge on the importance of free fatty acid metabolism on myocardial ischaemia/reperfusion injury and to provide an update on recent evidence on the role of hyperlipidemia and PCSK9 in myocardial infarction and cardioprotection.

Comprehensive Investigation of Circulating Biomarkers and Their Causal Role in Atherosclerosis-Related Risk Factors and Clinical Events

BACKGROUND

Circulating biomarkers have been previously associated with atherosclerosis-related risk factors, but the nature of these associations is incompletely understood.

METHODS

We performed multivariable-adjusted regressions and 2-sample Mendelian randomization analyses to assess observational and causal associations of 27 circulating biomarkers with 7 cardiovascular traits in up to 451 933 participants of the UK Biobank.

RESULTS

After multiple-testing correction (alpha=1.3×10^-4), we found a total of 15, 9, 21, 22, 26, 24, and 26 biomarkers strongly associated with coronary artery disease, ischemic stroke, atrial fibrillation, type 2 diabetes, systolic blood pressure, body mass index, and waist-to-hip ratio; respectively. The Mendelian randomization analyses confirmed strong evidence of previously suggested causal associations for several glucose- and lipid-related biomarkers with type 2 diabetes and coronary artery disease. Particularly interesting findings included a protective role of IGF-1 (insulin-like growth factor 1) in systolic blood pressure, and the strong causal association of lipoprotein(a) in coronary artery disease development (β, -0.13; per SD change in exposure and outcome and odds ratio, 1.28; P=2.6×10^-4 and P=7.4×10^-35, respectively). In addition, our results indicated a causal role of increased ALT (alanine aminotransferase) in the development of type 2 diabetes and hypertension (odds ratio, 1.59 and β, 0.06, per SD change in exposure and outcome; P=4.8×10^-11 and P=6.0×10^-5). Our results suggest that it is unlikely that CRP (C-reactive protein) and vitamin D play causal roles of any meaningful magnitude in development of cardiometabolic disease.

CONCLUSIONS

We confirmed and extended known associations and reported several novel causal associations providing important insights about the cause of these diseases, which can help accelerate new prevention strategies.

Proprotein convertase subtilisin/kexin type 9 inhibition in cardiovascular disease: current status and future perspectives

Proprotein convertase subtilisin/kexin type 9 (PCSK9) targets the degradation of low-density lipoprotein (LDL) receptors; it has been proved that its inhibition improves cardiovascular outcomes in patients with established atherosclerotic cardiovascular disease (ASCVD). Herein, we review the current status of PCSK9 inhibitors in clinical practice and the future scope of PCSK9 inhibition. The results of two recent large clinical trials reveal that two PCSK9 monoclonal antibodies evolocumab and alirocumab reduce the risk of a cardiovascular event on top of background statin therapy in patients with stable ASCVD and those with recent acute coronary syndrome, respectively. However, there are several ongoing concerns regarding the efficacy in reducing mortality, cost-effectiveness, and long-term safety of extremely low LDL cholesterol levels with PCSK9 inhibition. The results of ongoing cardiovascular outcomes trials with PCSK9 monoclonal antibodies for primary prevention and with small interfering RNA to PCSK9 for secondary prevention may help to shape the use of this new therapeutic class.

Lipoprotein(a) and Atherosclerotic Cardiovascular Disease: Current Understanding and Future Perspectives

PURPOSE

To review current knowledge of elevated lipoprotein(a) [Lp(a)] levels in relation to atherosclerotic cardiovascular disease (ASCVD) and discuss their potential use as biomarkers and therapeutic approaches in clinical practice.

METHODS

We summarized the current understanding and recent advances in the structure, metabolism, atherogenic mechanisms, standardized laboratory measurement, recommended screening populations, and prognostic value of Lp(a), with a special focus on the current potential treatment approaches for hyperlipoprotein(a)emia in patients with ASCVD.

RESULTS

Lp(a) is composed of LDL-like particle and characteristic apolipoprotein(a) [apo(a)] connected by a disulfide bond. Substantial evidence shows that elevated plasma Lp(a) level is a heritable, independent, and possibly causal risk factor for ASCVD through its proatherogenic, proinflammatory, and potentially prothrombotic properties. Current guidelines recommend Lp(a) measurement for patients with an intermediate-high risk of ASCVD, familial hypercholesterolemia, a family history of early ASCVD or elevated Lp(a), and progressive ASCVD despite receiving optimal therapy. Traditional Lp(a)-lowering approaches such as niacin, PCSK9 inhibitors, mipomersen, lomitapide, and lipoprotein apheresis were associated with a non-specific and limited reduction of Lp(a), intolerable side effects, invasive procedure, and high expense. The phase 2 randomized controlled trial of antisense oligonucleotide against the apo(a) encoding gene LPA mRNA showed that IONIS-APO(a)-L_RX could specifically reduce the level of Lp(a) by 90% with good tolerance, which may become a promising candidate for the prevention and treatment of ASCVD in the future.

CONCLUSIONS

It is reasonable to measure Lp(a) levels to reclassify ASCVD risk and manage individuals with elevated Lp(a) to further reduce the residual risk of ASCVD, especially with IONIS-APO(a)-L_RX.

PCSK9 Inhibition with alirocumab increases the catabolism of lipoprotein(a) particles in statin-treated patients with elevated lipoprotein(a)

BACKGROUND

Lipoprotein(a) (Lp(a)) is a low-density lipoprotein (LDL) particle containing apolipoprotein(a) (apo(a)) covalently linked to apolipoprotein B-100 (apoB). Statin-treated patients with elevated Lp(a) have an increased risk of atherosclerotic cardiovascular disease (ASCVD). Recent trials show that proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition decreases Lp(a) and cardiovascular events, particularly in high risk patients with elevated Lp(a). We investigated the kinetic mechanism whereby alirocumab, a PCSK9 inhibitor, lowers Lp(a) in statin-treated patients with high Lp(a) and ASCVD.

METHODS

The effects of 12-week alirocumab treatment (150 mg every 2 weeks) on apo(a) kinetics were studied in 21 patients with elevated Lp(a) concentration (>0.5 g/L). Apo(a) fractional catabolic rate (FCR) and production rate (PR) were determined using intravenous D3-leucine administration, mass spectrometry and compartmental modelling. All patients were on long-term statin treatment.

RESULTS

Alirocumab significantly decreased plasma concentrations of total cholesterol (-39%), LDL-cholesterol (-67%), apoB (-56%), apo(a) (-25%) and Lp(a) (-22%) (P< 0.001 for all). Alirocumab also significantly lowered plasma apo(a) pool size (-26%, P <0.001) and increased the FCR of apo(a) (+28%, P< 0.001), but did not alter apo(a) PR, which remained significantly higher relative to a reference group of patients on statins with normal Lp(a) (P< 0.001).

CONCLUSIONS

In statin-treated patients, alirocumab lowers elevated plasma Lp(a) concentrations by accelerating the catabolism of Lp(a) particles. This may be consequent on marked upregulation of hepatic receptors (principally for LDL) and/or reduced competition between Lp(a) and LDL particles for these receptors; the mechanism could contribute to the benefit of PCSK9 inhibition with alirocumab on cardiovascular outcomes.

Low-Density Lipoprotein Cholesterol Level cannot be too Low: Considerations from Clinical Trials, Human Genetics, and Biology

LDL cholesterol is by far the best established "causal" cardiovascular risk. It is distributed normally, and the mean value ranges around 100~120 mg/dl. In terms of preventive cardiology, we now know very well that the lower the LDL cholesterol, the better. Clinical usefulness of aggressive LDL-lowering therapies using statin, ezetimibe, and proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitors have been shown in primary and in secondary prevention settings. Additionally, the idea, based on recent randomized controlled trials (RCT), that the lower LDL cholesterol the better appears to be true for LDL as low as ~ 30 mg/dl. According to those data, recent guidelines in Europe and in Japan suggest the lowering of LDL cholesterol level ＜70 mg/dl for high-risk patients. However, the attainment rates of such "strict" goals seem to be quite low, probably because most cardiologists still have a sense of anxiety of "low" LDL cholesterol level. But "low" indicates no more than "lower" than the "average" range, which is not always implying the optimal range. Additionally, Mendelian randomization studies focusing on individuals exhibiting "low" LDL cholesterol suggest that "normal" LDL cholesterol levels might be too much for us. Moreover, LDL cholesterol levels of other primates are substantially lower than those in humans. In this review article, based on a series of evidence from clinical trials, human genetics, and biology, we provide the idea that we need to rethink what is the optimal range of LDL cholesterol level, instead of "normal" or "average" range.

Unusual responses to PCSK9 inhibitors in a clinical cohort utilizing a structured follow-up protocol

Objective

To characterize unusual responses to PCSK9 inhibitor (PCSK9i) therapy in a real-world setting, given their extremely low prevalence in clinical trials.

Methods

A retrospective study of patients seen in a structured academic PCSK9i clinic who had LDL-C measurements before and after initiation of PCSK9i (up to 12 months). Unusual response was defined as: (1) no response: no changes in LDL-C level at all time points; (2) delayed response: <30% LDL-C reduction by the third dose, but achieving this threshold at a later time; (3) reduced response: <30% LDL-C reduction at all time points; and (4) lost response: ≥30% LDL-C reduction by the third dose, but displaying <30% reduction at a later time.

Results

Of the 411 patients meeting inclusion criteria, 54 were initially classified as unusual responders. After excluding those not adherent to prescribed interventions, 31 patients (7.5%) were classified as true unusual responders. These included: 2 with no response, 12 with delayed response, 3 with reduced response, 6 with delayed or reduced response, 4 with lost response, and 4 with delayed and lost response. Response to PCSK9i therapy at all time points revealed higher on-treatment LDL-C values (94–100 vs. 47–51 ​mg/dL, p ​< ​0.001) and lower degree of percent reduction in LDL-C (23.3–34% vs. 61.1–64.5%, p ​< ​0.001) in the unusual versus usual responders. Lipoprotein (a) (Lp[a]) values were consistently higher in the unusual responders (81–92.5 vs. 28.5–52 ​mg/dL, p ​< ​0.01). Fold change in post-versus pre-treatment PCSK9 plasma results was similar between the two cohorts (p ​> ​0.05), suggesting that unusual responses were not due to insufficient plasma PCSK9 blockade. Multiple logistic regression analysis identified clinical FH (OR 2.9, 95% CI 1.27-7.24) and no ezetimibe therapy (OR 0.334, 95% CI 0.150-0.728) as factors related to true unusual response.

Conclusions

Unusual responses to PCSK9i in a clinical cohort are more common than reported in clinical trials. Of the suspected unusual responders, nearly half were the result of adherence issues, and thus careful medication reconciliation should be the first step in diagnosing an unusual response.

Lipoprotein removal mechanisms and aging: implications for the cardiovascular health of the elderly

PURPOSE OF REVIEW

The speed of removal from the plasma of apolipoprotein B-containing lipoproteins, for example, chylomicrons, VLDL and LDL is determinant of the plasma concentration of these lipoproteins, is influenced by genetic features and ambient factors, and has implications in atherogenesis. As aging increases the clinical complications of atherosclerosis, it is important to appraise the status of the removal mechanisms in elderly individuals.

RECENT FINDINGS

Removal of triglyceride-rich lipoproteins remnants is delayed but the triglyceride breakdown is unchanged in elderly individuals. The discovery of PCSK9, enzyme that degrades LDL receptors, and the recent observation that PCSK9 is elevated in the elderly raises another hypothesis to account for the increased LDL-cholesterol levels in the elderly. The removal of cholesterol from cells by HDL, the first step of cholesterol reverse transport is also less efficient in the elderly, which may compromise the body cholesterol homeostasis.

SUMMARY

Aging determines reduction of the efficiency of lipoprotein plasma removal mechanisms, which is implicated in increased incidence of cardia complications. Moreover, aging is frequently accompanied by physical activity reduction, weight gain, and metabolic disturbances that can further decrease the efficacy of the removal mechanisms. This knowledge is important for promoting cardiovascular health in the elderly and prolonging survival.

Research progress on alternative non-classical mechanisms of PCSK9 in atherosclerosis in patients with and without diabetes

The proprotein convertase subtilisin/kexin type 9 (PCSK9) acts via a canonical pathway to regulate circulating low-density lipoprotein-cholesterol (LDL-C) via degradation of the LDL receptor (LDLR) on the liver cell surface. Published research has shown that PCSK9 is involved in atherosclerosis via a variety of non-classical mechanisms that involve lysosomal, inflammatory, apoptotic, mitochondrial, and immune pathways. In this review paper, we summarized these additional mechanisms and described how anti-PCSK9 therapy exerts effects through these mechanisms. These additional pathways further illustrate the regulatory role of PCSK9 in atherosclerosis and offer an in-depth interpretation of how the PCSK9 inhibitor exerts effects on the treatment of atherosclerosis.

Relationship Between Low-Density Lipoprotein Cholesterol and Lipoprotein(a) Lowering in Response to PCSK9 Inhibition With Evolocumab

Background

Beyond their potent LDL (low‐density lipoprotein) cholesterol (LDL‐C)–lowering efficacy (50–60%), PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitors also reduce Lp(a) (lipoprotein[a]) levels by 25% to 30%, suggesting a 2:1 response ratio. We aimed to characterize the relationship between LDL‐C and Lp(a) lowering by evolocumab, a PCSK9 inhibitor, in a large clinical trial population and to determine the prevalence of concordant/discordant LDL‐C and Lp(a) responses to PCSK9 inhibition.

Methods and Results

Data were analyzed from 4 randomized, 12‐week, multicenter, phase 3 evolocumab trials. Patients with familial hypercholesterolemia, nonfamilial hypercholesterolemia, or statin intolerance participated in the trials. The main measure was the degree of concordance or discordance of LDL‐C and Lp(a) in response to PCSK9 inhibition; concordant response was defined as LDL‐C reduction >35% and Lp(a) reduction >10%. The study cohort comprised 895 patients (438 female; median age: 59.0 years [interquartile range: 51–66 years]). Baseline mean level of LDL‐C was 133.6 mg/dL (SE: 1.7) and median Lp(a) level was 46.4 mg/dL (interquartile range: 18.4–82.4 mg/dL). A discordant response was observed in 165 (19.7%) patients. With these cutoffs, the prevalence of discordance was higher when considering baseline Lp(a) concentrations >30 mg/dL (26.5%) or >50 mg/dL (28.6%).

Conclusions

We demonstrate high prevalence of discordance in LDL‐C and Lp(a) reduction in response to evolocumab, particularly when considering higher baseline Lp(a) concentrations, indicating the possibility of alternative pathways beyond LDLR (LDL receptor)–mediated clearance involved in Lp(a) reduction by evolocumab.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifiers: NCT01763827, NCT01763866, NCT01763905, NCT01763918.

See Editorial by Nestel

New Perspectives on Atherogenic Dyslipidaemia and Cardiovascular Disease

Over the past few decades, atherogenic dyslipidaemia has become one of the most common phenotypic presentations of lipid abnormalities, being strongly and unequivocally associated with an increased risk of cardiovascular (CV) disease. Despite the excellent results achieved from statin and non-statin management of LDL cholesterol and CV events prevention, there still remains a significant residual risk, associated with the prevalence of non-LDL cholesterol lipid patterns characterised by elevated triglyceride levels, low HDL cholesterol, a preponderance of small and dense LDL particles, accumulation of remnant lipoproteins and postprandial hyperlipidaemia. These qualitative and quantitative lipid modifications are largely associated with insulin resistance, type 2 diabetes and obesity, the prevalence of which has grown to epidemic proportions throughout the world. In this review, we analyse the pathophysiology of this particular dyslipidaemia, its relationship with the development of atherosclerotic CV disease and, finally, briefly describe the therapeutic approaches, including changes in lifestyle and current pharmacological interventions to manage these lipid alterations aimed at preventing CV events.

Proprotein convertase subtilisin/kexin type 9 inhibitors and lipoprotein(a)-mediated risk of atherosclerotic cardiovascular disease: more than meets the eye?

PURPOSE OF REVIEW

Evidence continues to mount for elevated lipoprotein(a) [Lp(a)] as a prevalent, independent, and causal risk factor for atherosclerotic cardiovascular disease. However, the effects of existing lipid-lowering therapies on Lp(a) are comparatively modest and are not specific to Lp(a). Consequently, evidence that Lp(a)-lowering confers a cardiovascular benefit is lacking. Large-scale cardiovascular outcome trials (CVOTs) of inhibitory mAbs targeting proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) may address this issue.

RECENT FINDINGS

Although the ability of PCSK9i to lower Lp(a) by 15-30% is now clear, the mechanisms involved continue to be debated, with in-vitro and in-vivo studies showing effects on Lp(a) clearance (through the LDL receptor or other receptors) and Lp(a)/apolipoprotein(a) biosynthesis in hepatocytes. The FOURIER CVOT showed that patients with higher baseline levels of Lp(a) derived greater benefit from evolocumab and those with the lowest combined achieved Lp(a) and LDL-cholesterol (LDL-C) had the lowest event rate. Meta-analysis of ten phase 3 trials of alirocumab came to qualitatively similar conclusions concerning achieved Lp(a) levels, although an effect independent of LDL-C lowering could not be demonstrated.

SUMMARY

Although it is not possible to conclude that PCSK9i specifically lower Lp(a)-attributable risk, patients with elevated Lp(a) could derive incremental benefit from PCSK9i therapy.

Lipoprotein(a) Removal Still a Mystery

See Article by Shapiro et al

Future role of proprotein convertase subtilisin/kexin type 9 inhibitors in preventive cardiology

PURPOSE OF REVIEW

The use of therapeutic monoclonal antibodies to target proprotein convertase subtilisin/kexin type 9 (PCSK9) represents a novel approach to the management of hypercholesteremia and prevention of atherosclerotic cardiovascular disease. We review the most recent literature relevant to PCSK9 inhibition with emphasis on how recent results and ongoing trials have and will continue to shape the use of this new therapeutic class in preventive cardiology.

RECENT FINDINGS

PCSK9 inhibitors reduce plasma lipoprotein(a) concentrations but a mechanistic understanding remains elusive. Evaluation of evolocumab for use in patients without prior myocardial infarction or stroke is underway (NCT03872401). Concerns regarding the cost-effectiveness of PCSK9 inhibitors have continued to thwart access to these drugs, though innovative models of care delivery and price reductions have improved this situation. Inclisiran, a small interfering ribonucleic acid (siRNA), reduces translation of PCSK9 and demonstrates more durable reductions in low-density lipoprotein-cholesterol (LDL-C). It is currently evaluated in the context of a phase III cardiovascular outcome trial in patients with established vascular disease (NCT03705234).

SUMMARY

The current scope of PCSK9 inhibitor therapy in preventive cardiology is limited to patients with familial hypercholesterolemia and/or established atherosclerotic cardiovascular disease. Future cardiovascular outcome trial results with PCSK9 blocking antibodies in primary prevention and with siRNA to PCSK9 in secondary prevention, improved understanding of the drivers of lipoprotein(a) reduction with PCSK9 inhibition, and cost-effectiveness will determine the future role of this therapeutic class.

Low Density Lipoprotein (LDL) Cholesterol as a Causal Role for Atherosclerotic Disease: Potential Role of PCSK9 Inhibitors

Proprotein convertase subtilisin/kexin type 9 (PCSK9)-related discoveries of the turn of the century have translated into substantial novelty in dyslipidemia treatment in the last 5 years. With chronic preventable atherosclerotic cardiovascular diseases (ASCVD) representing an epidemic of morbidity and mortality worldwide, low-density lipoprotein cholesterol (LDL-c) reduction represents a public health priority. By overcoming two major statin-related issues, namely intolerance and ineffectiveness, PCSK9 inhibitors have offered a safe and effective option in selected clinical settings where LDL-c reduction is required. Herein, we recapitulate recent findings, clinical applications, and ASCVD prevention potential of PCSK9 inhibition, with focus on anti-PCSK9 monoclonal antibodies, evolocumab and alirocumab.

The PCSK9 revolution: Current status, controversies, and future directions

Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) has revolutionized our understanding of cholesterol homeostasis and added to our arsenal against atherosclerotic cardiovascular disease (ASCVD). In a span of approximately 15 years, PCSK9 has morphed from an esoteric and rare cause of familial hypercholesterolemia (FH) into the most efficient cholesterol-lowering target ever known, with the completion of two large scale cardiovascular outcome trials showing positive results. Current Food and Drug Administration (FDA) approved modalities to inhibit PCSK9 are in the form of monoclonal antibodies which display an unparalleled degree of low-density lipoprotein cholesterol (LDL-C) lowering and expand upon the notion that lower LDL-C is better for ASCVD risk reduction. However, the accelerated pace of discovery and therapeutic development has left large gaps in our knowledge regarding the physiology and function of PCSK9. The aim of this review is to provide context to the discovery, history, treatment and current status of PCSK9 and its therapeutic inhibitors and highlight areas of controversy and future directions.