Recent Updates on the Use of PCSK9 Inhibitors in Patients with Atherosclerotic Cardiovascular Disease

The role of natural products as PCSK9 modulators: A review

A variety of mechanisms and drugs have been shown to attenuate cardiovascular disease (CVD) onset and/or progression. Recent researchers have identified a potential role of proprotein convertase subtilisin/kexin type 9 (PCSK9) in modulating lipid metabolism and reducing plasma low density lipoprotein (LDL) levels. PCSK9 is the central protein in the metabolism of LDL cholesterol (LDL-C) owing to its major function in LDL receptor (LDLR) degradation. Due to the close correlation of cardiovascular disease with lipid levels, many in vivo and in vitro investigations are currently underway studying the physiological role of PCSK9. Furthermore, many studies are actively investigating the mechanisms of various compounds that influence lipid associated-disorders and their associated cardiovascular diseases. PCSK9 inhibitors have been shown to have significant impact in the prevention of emerging cardiovascular diseases. Natural products can effectively be used as PCSK9 inhibitors to control lipid levels through various mechanisms. In this review, we evaluate the role of phytochemicals and natural products in the regulation of PCSK9, and their ability to prevent cardiovascular diseases. Moreover, we describe their mechanisms of action, which have not to date been delineated.

Inclisiran and cardiovascular events: a comprehensive review of efficacy, safety, and future perspectives

PURPOSE OF REVIEW

This review aims to offer an up-to-date evaluation of Inclisiran's (a small interfering RNA treatment) ability to decrease low-density lipoprotein cholesterol (LDL-C), as well as its safety and potential effects on decreasing cardiovascular risk.

RECENT FINDINGS

Inclisiran significantly lowers LDL-C levels, as shown by phase III studies, by inhibiting hepatic synthesis of proprotein convertase subtilisin kexin 9 (PCSK-9), a protein implicated in the degradation of LDL receptors. Inclisiran has the benefit of subcutaneous injection twice a year, which may reduce patient nonadherence when compared with other LDL-C reducing therapies such as statins and ezetimibe, which require daily dosing. When added on top of statins, a greater proportion of patients achieved recommended cholesterol goals. It has also demonstrated a good safety profile with few adverse effects.

SUMMARY

Inclisiran is a promising treatment for lowering LDL-C levels in people at high risk of atherosclerotic cardiovascular disease. It is a practical and well tolerated option for those who struggle to stick to medication regimes because of its twice-yearly dosage schedule and a good safety profile. Although it has been demonstrated to be effective in decreasing LDL-C, further research is needed to determine its impact on reducing cardiovascular events. Nonetheless, Inclisiran is a significant advancement in lipid-lowering medication and could improve patient outcomes.

Sex Differences in Cardiovascular Outcomes and Cholesterol-Lowering Efficacy of PCSK9 Inhibitors: Systematic Review and Meta-Analysis

Background

Guideline-recommended low-density lipoprotein cholesterol (LDL-C) thresholds are often not achieved in women. The proprotein convertase subtilisin/kexin type-9 inhibitor (PCSK9i) monoclonal antibodies can help further reduce LDL-C and major adverse cardiovascular events (MACE) although differences in efficacy by sex and type are less understood.

Objectives

The authors sought to determine if there are differences in the efficacy of LDL-C lowering and reduction in the risk of MACE by sex and type of PCSK9i.

Methods

A comprehensive literature search was done through October 17, 2022, for published trials comparing PCSK9i vs control. Outcomes assessed were LDL-C reduction and incidence of MACE following the use of PCSK9i vs placebo, stratified by sex and type of PCSK9i used.

Results

We identified 16 trials with 54,996 adults, and 15,143 (27.5%) of them were female. PCSK9i significantly reduced MACE compared to placebo in both women (HR: 0.86, 95% CI: 0.74-0.97, P < 0.001) and men (HR: 0.85, 95% CI: 0.79-0.91, P < 0.001) with no significant sex difference (MD -0.01, 95% CI: -0.14 to -0.13, P = 0.930). PCSK9i also significantly reduced LDL-C levels in both sexes at 12 weeks (females: MD -62.57, 95% CI: -70.24 to -54.91, P < 0.001; males: MD -66.19, 95% CI: -72.03 to -60.34, P < 0.001) and 24 weeks (females: MD -47.52, 95% CI: -52.94 to -42.09, P < 0.001; males: MD -54.07, 95% CI: -59.46 to -48.68, P < 0.001). Significant sex difference was seen in the LDL reduction of PCSK9i for both 12 weeks (males vs females: MD -4.55, 95% CI: -7.34 to -1.75, P < 0.01) and 24 weeks (males vs females: MD -7.11, 95% CI: -9.99 to -4.23, P < 0.001).

Conclusions

The use of PCSK9i results in significant LDL-C and MACE reduction in both males and females. While there is no significant sex difference in MACE reduction, LDL-C reduction is greater in males than in females. Our data support the equal use of PCSK9i in all eligible patients, regardless of sex.

PCSK9 Inhibitors Reduce PCSK9 and Early Atherogenic Biomarkers in Stimulated Human Coronary Artery Endothelial Cells

Despite reports on the efficacy of proprotein convertase subtilisin-Kexin type 9 (PCSK9) inhibitors as a potent lipid-lowering agent in various large-scale clinical trials, the anti-atherogenic properties of PCSK9 inhibitors in reducing PCSK9 and atherogenesis biomarkers via the NF-ĸB and eNOS pathway has yet to be established. This study aimed to investigate the effects of PCSK9 inhibitors on PCSK9, targeted early atherogenesis biomarkers, and monocyte binding in stimulated human coronary artery endothelial cells (HCAEC). HCAEC were stimulated with lipopolysaccharides (LPS) and incubated with evolocumab and alirocumab. The protein and gene expression of PCSK9, interleukin-6 (IL-6), E-selectin, intercellular adhesion molecule 1 (ICAM-1), nuclear factor kappa B (NF-ĸB) p65, and endothelial nitric oxide synthase (eNOS) were measured using ELISA and QuantiGene plex, respectively. The binding of U937 monocytes to endothelial cell capacity was measured by the Rose Bengal method. The anti-atherogenic effects of evolocumab and alirocumab were contributed to by the downregulation of PCSK9, early atherogenesis biomarkers, and the significant inhibition of monocyte adhesion to the endothelial cells via the NF-ĸB and eNOS pathways. These suggest the beyond cholesterol-lowering beneficial effects of PCSK9 inhibitors in impeding atherogenesis during the initial phase of atherosclerotic plaque development, hence their potential role in preventing atherosclerosis-related complications.

Berberine: Ins and outs of a nature-made PCSK9 inhibitor

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protein and a critical regulator of low-density lipoprotein-cholesterol (LDL-C) through inducing degradation of the LDL receptor (LDLR) within the hepatocyte lysosome. PCSK9 deficiency significantly improves the survival rate of cardiovascular disease (CVDs) patients. Up to now, various PCSK9 inhibition approaches have been tested. However, the currently available PCSK9 inhibitors' widespread use is limited due to their inconvenient method of administration and high cost. On the other hand, inhibiting PCSK9 with nutraceuticals is safe and affordable. The plant-derived compound berberine has shown anti-PCSK9 activity in several studies. Berberine is an isoquinoline quaternary alkaloid of phyto origin. Berberine treatment boosts the hepatic expression of LDLRs, while decreasing the expression and secretion of the LDLR modulator PCSK9. The current review presents a collection of in vitro and in vivo studies investigating berberine's effects on PCSK9 mRNA expression, protein level, and function.

The PCSK9 discovery, an inactive protease with varied functions in hypercholesterolemia, viral infections, and cancer

In 2003, the sequences of mammalian proprotein convertase subtilisin/kexin type 9 (PCSK9) were reported. Radiolabeling pulse-chase analyses demonstrated that PCSK9 was synthesized as a precursor (proPCSK9) that undergoes autocatalytic cleavage in the endoplasmic reticulum into PCSK9, which is then secreted as an inactive enzyme in complex with its inhibitory prodomain. Its high mRNA expression in liver hepatocytes and its gene localization on chromosome 1p32, a third locus associated with familial hypercholesterolemia, other than LDLR or APOB, led us to identify three patient families expressing the PCSK9 variants S127R or F216L. Although Pcsk9 and Ldlr were downregulated in mice that were fed a cholesterol-rich diet, PCSK9 overexpression led to the degradation of the LDLR. This led to the demonstration that gain-of-function and loss-of-function variations in PCSK9 modulate its bioactivity, whereby PCSK9 binds the LDLR in a nonenzymatic fashion to induce its degradation in endosomes/lysosomes. PCSK9 was also shown to play major roles in targeting other receptors for degradation, thereby regulating various processes, including hypercholesterolemia and associated atherosclerosis, vascular inflammation, viral infections, and immune checkpoint regulation in cancer. Injectable PCSK9 monoclonal antibody or siRNA is currently used in clinics worldwide to treat hypercholesterolemia and could be combined with current therapies in cancer/metastasis. In this review, we present the critical information that led to the discovery of PCSK9 and its implication in LDL-C metabolism. We further analyze the underlying functional mechanism(s) in the regulation of LDL-C, as well as the evolving novel roles of PCSK9 in both health and disease states.

Potential of Phage Display Antibody Technology for Cardiovascular Disease Immunotherapy

Cardiovascular disease (CVD) is one of the leading causes of death worldwide. CVD includes coronary artery diseases such as angina, myocardial infarction, and stroke. "Lipid hypothesis" which is also known as the cholesterol hypothesis proposes the linkage of plasma cholesterol level with the risk of developing CVD. Conventional management involves the use of statins to reduce the serum cholesterol levels as means for CVD prevention or treatment. The regulation of serum cholesterol levels can potentially be regulated with biological interventions like monoclonal antibodies. Phage display is a powerful tool for the development of therapeutic antibodies with successes over the recent decade. Although mainly for oncology, the application of monoclonal antibodies as immunotherapeutic agents could potentially be expanded to CVD. This review focuses on the concept of phage display for antibody development and discusses the potential target antigens that could potentially be beneficial for serum cholesterol management.

Structure-activity relationship and biological evaluation of berberine derivatives as PCSK9 down-regulating agents

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protein and its deficiency markedly enhanced the survival rate of patient with cardiovascular diseases (CVDs). Forty berberine (BBR) derivatives were synthesized and evaluated for their activities on down-regulating the transcription of PCSK9 in HepG2 cells, taking BBR as the lead. Structure-activity relationship (SAR) analysis revealed that 2,3-dimethoxy moiety might be beneficial for activity. Among them, 9k displayed the most potent activity with IC₅₀ value of 9.5 ± 0.5 μM, better than that of BBR. Also, it significantly decreased PCSK9 protein level at cellular level, as well as in the liver and serum of mice in vivo. Furthermore, 9k markedly increased LDLR expression and LDL-C clearance via down-regulating PCSK9 protein. The mechanism of action of 9k is targeting HNF1α and/or Sp1 cluster modulation upstream of PCSK9, a different one from BBR. Therefore, 9k might have the potential to be a novel PCSK9 transcriptional inhibitor for the treatment of atherosclerosis, worthy for further investigation.

Serum lipoprotein(a) and risk of periprocedural myocardial injury in patients undergoing percutaneous coronary intervention

Recent studies and guidelines have indicated that lipoprotein(a) [Lp(a)]was an independent risk factor of arteriosclerotic cardiovascular disease (ASCVD). This study aimed to determine the relationship between serum Lp(a) levels and the risk of periprocedural myocardial injury following percutaneous coronary intervention (PCI) in coronary heartdisease (CHD) patients. This study enrolled 528 nonacute myocardial infarction (AMI) coronary heart disease (CHD) patients who successfully underwent PCI. Fasting serum lipids including Lp(a) were tested before PCI. High-sensitivity cardiac troponin I (hs-cTnI) was tested before PCI and 24 h after PCI. Univariate and multivariate logistic regression analyses were used to determine the relationship between preprocedural Lp(a) levels and postprocedural cTnI elevation from 1 × upper limit of normal (ULN) to 70 × ULN. As a continuous variable, multivariate analyses adjusting for conventional covariates and other serum lipids revealed that increased Lp(a) levels were independently associated with the risk of elevated postprocedural cTnI values above 1 × ULN (odds ratio [OR] per log-unit higher: 1.31, 95% confidence interval [CI]: 1.02-1.68, P = 0.033], 5 × ULN (OR: 1.25, 95%CI: 1.02-1.53, P = 0.032), 10 × ULN (OR: 1.48, 95%CI: 1.18-1.86, P = 0.001) and 15 × ULN (OR: 1.28, 95%CI: 1.01-1.61, P = 0.038). As a categorical variable, Lp(a) > 300 mg/L was an independent risk factor of postproceduralc TnI≥1 × ULN (OR 2.17, 95%CI 1.12-4.21, P = 0.022), ≥5 × ULN (OR 1.82, 95%CI 1.12-2.97, P = 0.017) and ≥10 × ULN (OR 2.17, 95%CI 1.33-3.54, P = 0.002). Therefore, it could be concluded that elevated preprocedural Lp(a) levels were associated with the risk of PCI-related myocardial injury in non-AMI CHD patients.

Diabetic vasculopathy: macro and microvascular injury

PURPOSE OF REVIEW

Diabetes is a common and prevalent medical condition as it affects many lives around the globe. Specifically, type-2 Diabetes (T2D) is characterized by chronic systemic inflammation alongside hyperglycemia and insulin resistance in the body, which can result in atherosclerotic legion formation in the arteries and thus progression of related conditions called diabetic vasculopathies. T2D patients are especially at risk for vascular injury; adjunct in many of these patients heir cholesterol and triglyceride levels reach dangerously high levels and accumulate in the lumen of their vascular system.

RECENT FINDINGS

Microvascular and macrovascular vasculopathies as complications of diabetes can accentuate the onset of organ illnesses, thus it is imperative that research efforts help identify more effective methods for prevention and diagnosis of early vascular injuries. Current research into vasculopathy identification/treatment will aid in the amelioration of diabetes-related symptoms and thus reduce the large number of deaths that this disease accounts annually.

SUMMARY

This review aims to showcase the evolution and effects of diabetic vasculopathy from development to clinical disease as macrovascular and microvascular complications with a concerted reference to sex-specific disease progression as well.

Meta-Analysis of Dyslipidemia Management for the Prevention of Ischemic Stroke Recurrence in China

Background: The benefit of blood cholesterol reduction for secondary prevention of ischemic stroke remains undetermined in Chinese patients. The purpose of this meta-analysis was to determine whether lipid-lowering agents including statins, fibrates, nicotinic acid, and ezetimibe reduced the risk of recurrent stroke in ischemic stroke patients in China and whether such findings could inform treatment decisions for blood lipid-lowering treatment in China. Methods: The English electronic databases PubMed, EMBASE, Cochrane Library and Chinese databases CNKI, Sino-Med, Wan Fang, and VIP were searched for studies published between January 1990 and April 2020. This meta-analysis included published data from trials that randomly assigned patients to groups treated with either blood lipid-lowering regimens or placebo. Effect comparisons were made using fixed effects model in meta-analysis and linear and spline regression were performed to identify the relative risk of stroke recurrence. The primary outcome was the reduction of total ischemic stroke events, and relative risk values were obtained using a risk prediction equation developed from the control groups of the included trials. Results: Five studies including 4,999 individuals with available data met the inclusion criteria. Relative to the control groups, the pooled estimated odds ratio (OR) for recurrent stroke among those who received lipid-lowering therapy was 0.79 (95% confidence interval [CI]: 0.63-1.00). A 50% or greater reduction in low-density lipoprotein cholesterol (LDL-C) significantly reduced the risk of ischemic stroke recurrence (OR: 0.15 [95% CI: 0.11-0.20]). The overall beneficial effect of statin therapy was confirmed to prevent ischemic stroke with an OR of 0.51 (95% CI: 0.36-0.72). Conclusions: Effective lipid-lowering therapy could decrease the blood LDL-C level, which had a protective effect against stroke recurrence. These results support the use of predicted baseline cerebrovascular disease risk equations to inform decisions regarding blood lipid-lowering treatment in ischemic stroke patients in China.

PCSK9 Inhibition: New Treatment Options and Perspectives to Lower Atherogenic Lipoprotein Particles and Cardiovascular Risk

PURPOSE OF REVIEW

To summarize latest clinical studies and to put them into perspectives for clinical relevant subgroups and new therapeutic options.

RECENT FINDINGS

Have investigated PCSK9 inhibitors in patients with very high cardiovascular risk and insufficient LDL cholesterol lowering under current maximal tolerated lipid-lowering therapy, patients with statin intolerance, or genetic forms of familiar hypercholesterolemia, and patients on LDL apheresis. Purpose of recent cardiovascular endpoint trials has proven cardiovascular benefit of this new approach. PCSK9 inhibition with fully humanized antibodies has proven to be effective, safe, and well-tolerated in reducing cardiovascular risk by LDL cholesterol lowering. Therefore, research interests are to elucidate additional roles and effects of PCSK9 modulation on inflammation and cellular processes of the atherosclerotic plaque and to develop alternative therapeutic strategies addressing PCSK9 as a proven and therefore promising drug target.