PCSK9 inhibitors: A new era of lipid lowering therapy

Early administration of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors in patients with acute coronary syndrome: a systematic review and meta-analysis

BACKGROUND

High-intensity statin therapy is currently recommended initial guideline therapy in ACS treatment. However, only a minority of patients are achieving LDL-C attainment goal at 6 months. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are on recommended guideline therapy post-ACS if LDL-C goal attainment is not achieved after high-intensity statin (4-6 weeks) and after the addition of ezetimibe if guideline goal attainment is not achieved after an additional 4-6 weeks. Thus, it has been recommended that PCSK9 inhibitors be considered earlier post-ACS. However, the efficacy of early PCSK9 inhibitors initiation in ACS patients remains uncertain.

METHODS

This systematic review and meta-analysis was conducted following PRISMA guidelines. Randomized controlled trials (RCTs) and observational studies involving ACS patients who received PCSK9 inhibitors within 48 h of hospitalization were included. Common and random effects models were used to evaluate the pooled effect of early PCSK9 inhibitor administration. Nine RCTs and three cohort studies were included.

RESULTS

Early PCSK9 inhibitor administration reduced the incidence of MI, ACS hospitalization, and revascularization at 6-18 months post-ACS. Although there was a drift towards reduced stroke, all-cause mortality, and cardiovascular death, no statistically significant reduction was observed. Additionally, PCSK9 inhibitors significantly enhanced lipid control at 4-12 weeks after index hospitalization.

CONCLUSION

Early PCSK9 inhibitors initiation in ACS patients reduces MACE and improves lipid profiles. While the results propose promising benefits in terms of stroke and mortality, further research with longer follow-up is required for more decisive evidence.

Therapeutic Monoclonal Antibodies for Metabolic Disorders: Major Advancements and Future Perspectives

PURPOSE OF REVIEW

Globally, the prevalence of metabolic disorders is rising. Elevated low-density lipoprotein (LDL) cholesterol is a hallmark of familial hypercholesterolemia, one of the most prevalent hereditary metabolic disorders and another one is Diabetes mellitus (DM) that is more common globally, characterised by hyperglycemia with low insulin-directed glucose by target cells. It is still known that low-density lipoprotein cholesterol (LDL-C) increases the risk of cardiovascular disease (CVD). LDL-C levels are thought to be the main therapeutic objectives.

RECENT FINDINGS

The primary therapy for individuals with elevated cholesterol levels is the use of statins and other lipid lowering drugs like ezetimibe for hypercholesterolemia. Even after taking statin medication to the maximum extent possible, some individuals still have a sizable residual cardiovascular risk. To overcome this proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors-monoclonal antibodies (mAbs) are a novel class of systemic macromolecules that have enhanced LDL-C-lowering efficacy. Along with this other inhibitor are used like Angiopoeitin like 3 inhibitors. Research on both humans and animals has shown that anti-CD3 antibodies can correct autoimmune disorders like diabetes mellitus. Individuals diagnosed with familial hypercholesterolemia (FH) may need additional treatment options beyond statins, especially when facing challenges such as statin tolerance or the inability of even the highest statin doses to reach the desired target cholesterol level. Here is the summary of PCSK9, ANGPTL-3 and CD3 inhibitors and their detailed information. In this review we discuss the details of PCSK9, ANGPTL-3 and CD3 inhibitors and the current therapeutic interventions of using the monoclonal antibodies in case of the metabolic disorder. We further present the present studies and the future prospective of the same.

Chemical constituents from the roots of Cynanchum wilfordii with PCSK9 secretion inhibitory activities

From the Cynanchum wilfordii roots, 32 compounds, including 5 previously undescribed (1, 4-6, 12) and 27 known (2, 3, 7-11, 13-32) compounds, were isolated, and their structures were elucidated using NMR spectroscopic data and MS data aided by ECD calculations or the modified Mosher's reaction. All isolates were tested for their inhibitory effects on proprotein convertase subtilisin/kexin type 9 (PCSK9) secretion. Among the isolates, compound 4, a methyl cholesterol analog, exhibited the most potent effect in reducing PCSK9 secretion, along with PCSK9 downregulation at the mRNA and protein levels via FOXO1/3 upregulation. Moreover, compound 4 attenuated statin-induced PCSK9 expression and enhanced the uptake of DiI-LDL low-density lipoprotein. Thus, compound 4 is suggested to be a potential candidate for controlling cholesterol levels.

Specific circulating miRNAs are associated with plasma lipids in a healthy American cohort

Low-density lipoprotein cholesterol (LDL-c) is both a therapeutic target and a risk factor for cardiovascular disease (CVD). MicroRNA (miRNA) has been shown to regulate cholesterol homeostasis, and miRNA in blood circulation has been linked to hypercholesterolemia. However, few studies to date have associated miRNA with phenotypes like LDL-c in a healthy population. To this end, we analyzed circulating miRNA in relation to LDL-c in a healthy cohort of 353 participants using two separate bioinformatic approaches. The first approach found that miR-15b-5p and miR-16-5p were upregulated in individuals with at-risk levels of LDL-c. The second approach identified two miRNA clusters, one that positively and a second that negatively correlated with LDL-c. Included in the cluster that positively correlated with LDL-c were miR-15b-5p and miR-16-5p, as well as other miRNA from the miR-15/107, miR-30, and let-7 families. Cross-species analyses suggested that several miRNAs that associated with LDL-c are conserved between mice and humans. Finally, we examined the influence of diet on circulating miRNA. Our results robustly linked circulating miRNA with LDL-c, suggesting that miRNA could be used as biomarkers for hypercholesterolemia or targets for developing cholesterol-lowering drugs.NEW & NOTEWORTHY This study explored the association between circulating microRNA (miRNA) and low-density lipoprotein cholesterol (LDL-c) in a healthy population of 353 participants. Two miRNAs, miR-15b-5p and miR-16-5p, were upregulated in individuals with at-risk LDL-c levels. Several miRNA clusters were positively and negatively correlated with LDL-c and are known to target mRNA involved in lipid metabolism. The study also investigated the influence of diet on circulating miRNA, suggesting potential biomarkers for hypercholesterolemia.

PCSK9 and Lipid Metabolism: Genetic Variants, Current Therapies, and Cardiovascular Outcomes

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a crucial role in the modulation of lipid metabolism as a critical negative regulator of hepatic low-density lipoprotein receptor (LDLR) levels and circulating low-density lipoprotein (LDL) clearance. Numerous gain-of-function (GOF) mutations in PCSK9 have been identified as causing familial hypercholesterolemia (FH) by reducing LDLR levels, and loss-of-function (LOF) mutations associated with a hypercholesterolemia phenotype protective against atherosclerosis. PCSK9 represents an example of successful translational research resulting in the identification of PCSK9 as a major drug target for a lipid-lowering therapy. To explore the genetic constitution of PCSK9 and its biologic role, in this review, we summarize the current evidence of clinically significant PCSK9 genetic variants involved in lipid metabolism as well as emphasize the importance of PCSK9 inhibition for the improvement of cardiovascular outcomes by conducting a meta-analysis of the available data on the incidence of cardiovascular disease events.

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.

Towards Optimal Cardiovascular Health: A Comprehensive Review of Preventive Strategies

Heart disease remains a prominent global health concern, with cardiovascular disease (CVD) standing as a leading cause of death worldwide. Preventing heart disease not only decreases the risk of premature death but also mitigates complications like heart attacks, strokes, and arrhythmias, thereby enhancing overall health and quality of life. The economic burden of heart disease treatment highlights the importance of implementing preventive measures, such as lifestyle changes and early interventions, which can alleviate healthcare costs. These strategies, targeting risk factors like hypertension (HTN), diabetes mellitus (DM), dyslipidemia, and obesity, not only prevent heart disease but also reduce the risk of other health issues. Herein, this review covers various preventive measures, including dietary interventions, exercise, controlling HTN, DM, cholesterol, and weight, smoking cessation, and pharmacological interventions. By critically analyzing the guidelines and leveraging robust data alongside variations in recommendations, this review aims to elucidate effective primary prevention strategies for CVD.

Targeting the vivid facets of apolipoproteins as a cardiovascular risk factor in rheumatoid arthritis

Mostly, cardiovascular diseases are blamed for casualties in rheumatoid arthritis (RA) patients. Customarily, dyslipidemia is probably the most prevalent underlying cause of untimely demise in people suffering from RA as it hastens the expansion of atherosclerosis. The engagement of inflammatory cytokines like tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6), etc., is crucial in the progression and proliferation of both RA and abnormal lipid parameters. Thus, lipid abnormalities should be monitored frequently in patients with both primary and advanced RA stages. An advanced lipid profile examination, i.e., direct role of apolipoproteins associated with various lipid molecules is a more dependable approach for better understanding of the disease and selecting suitable therapeutic targets. Therefore, studying their apolipoproteins is more relevant than assessing RA patients' altered lipid profile levels. Among the various apolipoprotein classes, Apo A1 and Apo B are primarily being focused. In addition, it also addresses how calculating Apo B:Apo A1 ratio can aid in analyzing the disease's risk. The marketed therapies available to control lipid abnormalities are associated with many other risk factors. Hence, directly targeting Apo A1 and Apo B would provide a better and safer option.

Hypercholesterolemia: a literature review on management using tafolecimab: a novel member of PCSK9 monoclonal antibodies

Background

Cardiovascular diseases (CVD) persist as the leading cause of mortality globally, with atherosclerotic cardiovascular disease (ASCVD), including hypercholesterolaemia, being a significant contributor. Hyperlipidemia management includes various lipid-lowering drugs, including statins, Bempedoic acid, inclisiran, Lomitapide, ANGPTL3 inhibitors, and PCSK9 inhibitors. Statins have traditionally dominated lipid management therapies; however, a subset of patients remains unresponsive or intolerant to this therapy, necessitating novel therapeutic approaches. Tafolecimab, a promising and novel PCSK9 monoclonal antibody, demonstrated significant LDL-C reduction and a favourable safety profile in clinical trials.

Objective

This review aimed to discuss the role and efficacy of Tafolecimab in the management of hypercholesterolaemia.

Methods

The authors searched online databases, including PubMed, Scopus, and Embase, for articles related to talofecimab.

Discussion

The efficacy of Tafolecimab in diverse patient populations, including those with comorbid conditions and various lipid disorders, has been explored. Ongoing trials, such as CREDIT-1, CREDIT-2, and CREDIT-4, have provided valuable insights into Tafolecimab's potential as a lipid-lowering agent. Moreover, the drug's extended dosing interval may enhance patient compliance and reduce treatment costs. It has also been found that Tafolecimab has more affinity for PCSK9 and a longer duration of LDL-C reduction than other monoclonal antibody drugs such as evolocumab. Thus, this review focuses on Tafolecimab, a novel PCSK9 monoclonal antibody, its mechanism of action, clinical trial outcomes, safety profile, and potential role in hypercholesterolaemia management. Despite its assuring potential, the long-term impact of Tafolecimab on cardiovascular outcomes remains to be fully elucidated, necessitating further research. Regulatory authorities like the FDA and EMA should also evaluate Tafolecimab's risks and benefits.

Conclusion

In conclusion, Tafolecimab shows potential as an innovative therapeutic option for hypercholesterolaemia, particularly in patients with specific risk factors, but warrants additional research.

Classical and Novel Lipid-Lowering Therapies for Diabetic Patients with Established Coronary Artery Disease or High Risk of Coronary Artery Disease-A Narrative Clinical Review

Diabetic atherosclerosis is a complex process that is characterized by diffuse and unstable lesions increasing 2-4-fold the risk of adverse cardiovascular (CV) events. Diabetic dyslipidemia has a predominant role in coronary artery disease (CAD) and has been the target of classical and emerging pharmaceutical agents with established or promising CV benefits. The aim of the present narrative review was to summarize the effects of classical and novel lipid-lowering pharmaceutical agents on lipid profile and CV outcomes in diabetic patients with established CAD or high risk of CAD. Statins remain the first-line treatment for all diabetic patients since they considerably ameliorate lipid parameters and non-lipid CV risk factors, leading to reduced CV morbidity and mortality. Complementary to statins, ezetimibe exerts lipid-lowering properties with modest but significant reductions in major adverse cardiovascular events (MACEs) and CV mortality. PCSK9 inhibitors considerably reduce LDL-C levels and lower MACEs in diabetic patients. On the other hand, fibrates may confer a very modest decline in MACE incidence, while the CV impact of omega-3 fatty acids is promising but remains questionable. Bempedoic acid and inclisiran have a potential therapeutic role in the management of diabetic dyslipidemia, but this is still not adequately documented. Given the heightened CV risk among individuals with diabetes, more decisive results would be of great importance in the utility of all these drugs.

Atherosclerotic cardiovascular disease landscape in Singapore

Cardiovascular disease (CVD) is the leading cause of death worldwide, accounting for over one-third of all deaths in Singapore. An analysis of age-standardized mortality rates (ASMR) for CVD in Singapore revealed a deceleration in the initial rapid decline in ASMR. A decrease in smoking prevalence may have contributed to the initial rapid decline in ASMR. Furthermore, other major risk factors, such as diabetes mellitus, hypertension, elevated low-density lipoprotein levels, and obesity, are steadily rising. Singapore's CVD economic burden is estimated to be 8.1 billion USD (11.5 billion SGD). The burden of CVD can only be reduced using individual and population-based approaches. Prevention programs must also be developed based on an understanding of risk trends. Therefore, this article attempts to capture the burden of CVD, trends in risk factor control, preventive care, disparities, and current unmet needs, particularly in atherosclerotic cardiovascular disease management in Singapore.

Inclisiran siRNA technology in the management of dyslipidemia: A narrative review of clinical trials

RNA interference therapies, particularly small interfering RNAs (siRNAs) like Inclisiran, have shown great potential in managing dyslipidemia, a significant risk factor for cardiovascular disease. Inclisiran targets pro-protein convertasesubtilisin/kexin type 9 (PCSK9) mRNA to reduce low-density lipoprotein cholesterol (LDL-C) levels. This review evaluates Inclisiran's efficacy, safety, and clinical applications in managing dyslipidemia. A review of clinical trials evaluating Inclisiran's efficacy and safety in dyslipidemia management was conducted. PubMed, Embase, Google Scholar and Scopus were searched for relevant trials. Inclusion criteria covered clinical trials in English, published within the last six years, involving human subjects. 12 clinical trials were included in this review, demonstrating Inclisiran's consistent efficacy in reducing LDL-C levels across diverse patient populations, even in statin intolerance or resistance cases. The efficacy was observed over various durations, with some trials extending up to 4 years. Inclisiran demonstrated a favourable safety profile, with mild adverse events reported in most trials, suggesting its potential as a well-tolerated treatment option. Inclisiran's consistent efficacy and safety profile make it a promising option for managing dyslipidemia. Future studies should confirm its long-term effects and explore its clinical implications in diverse patient populations and high-risk scenarios.

Treatment of dyslipidemia in acute coronary syndrome

Despite numerous improvements in the management of acute coronary syndrome(ACS), it is a major cause of mortality in India. Lipids play a critical role in pathogenesis of ACS and reduction of lipid parameters plays a pivotal role in secondary prevention. High total cholesterol and high low-density lipoprotein(LDL) are the major lipid abnormalities globally as well as in Indians. Among all the lipid parameters, LDL is the primary target of lipid-lowering therapies across the globe. High-dose statins, ezetimibe, proprotein convertase subtilisin/kexin type 9 inhibitors, and bempedoic acid are recommended therapies for LDL reduction in ACS patients. Statins have pleiotropic effects on the modulation of thrombogenesis, endothelial dysfunction, and myocardial protection. Multiple randomised controlled trials and meta-analyses have shown that the use of high-dose statin has significant benefits in ACS. LDL reduction goal is < 55 mg/dl or at least 50 % reduction from the baseline regardless of age or gender. Non-fasting LDL should be measured soon after the ACS as it varies minimally with food intake. The first line of therapy after ACS is to advise lifestyle modifications, combination therapy including high-dose statin with ezetimibe, and evaluation after 4-6 weeks of the index event. If the goal is not achieved then PCSK 9 inhibitors or Bempedoic acid should be used in combination with statins and ezetimibe to reduce recurrent ischaemic events. Despite the proven effect of these lipid-lowering therapies, undertreatment is still a big hurdle across the globe. Prohibitive costs, adverse effects, medication non-adherence, variation in health practice in different countries, and clinical inertia to prescribe this medication by physicians are the main reasons for the undertreatment.

Post-translational regulation of the low-density lipoprotein receptor provides new targets for cholesterol regulation

The amount of the low-density lipoprotein receptor (LDLR) on the surface of hepatocytes is the primary determinant of plasma low-density lipoprotein (LDL)-cholesterol level. Although the synthesis and cellular trafficking of the LDLR have been well-documented, there is growing evidence of additional post-translational mechanisms that regulate or fine tune the surface availability of the LDLR, thus modulating its ability to bind and internalise LDL-cholesterol. Proprotein convertase subtilisin/kexin type 9 and the asialoglycoprotein receptor 1 both independently interact with the LDLR and direct it towards the lysosome for degradation. While ubiquitination by the E3 ligase inducible degrader of the LDLR also targets the receptor for lysosomal degradation, ubiquitination of the LDLR by a different E3 ligase, RNF130, redistributes the receptor away from the plasma membrane. The activity of the LDLR is also regulated by proteolysis. Proteolytic cleavage of the transmembrane region of the LDLR by γ-secretase destabilises the receptor, directing it to the lysosome for degradation. Shedding of the extracellular domain of the receptor by membrane-type 1 matrix metalloprotease and cleavage of the receptor in its LDL-binding domain by bone morphogenetic protein-1 reduces the ability of the LDLR to bind and internalise LDL-cholesterol at the cell surface. A better understanding of how the activity of the LDLR is regulated will not only unravel the complex biological mechanisms controlling LDL-cholesterol metabolism but also could help inform the development of alternative pharmacological intervention strategies for the treatment of hypercholesterolaemia.

Long-Term Efficacy and Tolerability of PCSK9 Targeted Therapy: A Review of the Literature

Increased plasma levels of low-density lipoprotein cholesterol (LDL-C) are causally associated with atherosclerotic cardiovascular disease (ASCVD), and statins that lower LDL-C have been the cornerstone of ASCVD prevention for decades. However, guideline-recommended LDL-C targets are not achieved in about 60% of statin users. Proprotein convertase subtilisin/kexin type 9 (PCSK9)-targeted therapy effectively lowers LDL-C levels and has been shown to reduce ASCVD risk. A growing body of scientific and clinical evidence shows that PCSK9-targeted therapy offers an excellent safety and tolerability profile with a low incidence of side effects in the short term. In this review, we present and discuss the current clinical and scientific evidence pertaining to the long-term efficacy and tolerability of PCSK9-targeted therapy.

Targeting systemic inflammation in metabolic disorders. A therapeutic candidate for the prevention of cardiovascular diseases?

Cardiovascular disease (CVD) remains the leading cause of death and disability worldwide. While many factors can contribute to CVD, atherosclerosis is the cardinal underlying pathology, and its development is associated with several metabolic risk factors including dyslipidemia and obesity. Recent studies have definitively demonstrated a link between low-grade systemic inflammation and two relevant metabolic abnormalities: hypercholesterolemia and obesity. Interestingly, both metabolic disorders are also associated with endothelial dysfunction/activation, a proinflammatory and prothrombotic phenotype of the endothelium that involves leukocyte infiltration into the arterial wall, one of the earliest stages of atherogenesis. This article reviews the current literature on the intricate relationship between hypercholesterolemia and obesity and the associated systemic inflammation and endothelial dysfunction, and discusses the effectiveness of present, emerging and in-development pharmacological therapies used to treat these metabolic disorders with a focus on their effects on the associated systemic inflammatory state and cardiovascular risk.

Identification of benzothiazoles as novel PCSK9 inhibitors

Proprotein convertase subtilisin kexin type 9 (PCSK9) is a clinically validated target on the treatment of cardiovascular disease (CVD). PCSK9 can regulate the hepatocyte surface low density lipoprotein receptor (LDLR) level by binding to LDLR and leading to their degradation in the lysosome. The clinical use of two monoclonal antibodies (alirocumab and evolocumab, approved in 2015) and one small interfering RNA (inclisiran, approved in 2020) which can inhibit PCSK9 function proved that they are very effective in lowering low density lipoprotein cholesterol (LDL-C). However, the high treatment costs and parenteral administration of these drugs prohibited widespread use and reduced their long-term advantage. Comparatively, small molecule drugs have many incomparable advantages of macromolecules, such as lower treatment cost, more drug administration options, superior pharmacokinetic properties, less adverse immunogenic responses and better affordable production. In this paper, we identified a series of benzothiazoles small molecule PCSK9 inhibitors through extensive screening. The structure and activity relationship (SAR) was summarized to facilitate further optimization. Moreover, the primary mechanism of action of the most potent compound was also investigated.

Role of proprotein convertase subtilisin/kexin type 9 (PCSK9) in diabetic complications

Cardiovascular disease (CVD) complications have remained a major cause of death among patients with diabetes. Hence, there is a need for effective therapeutics against diabetes-induced CVD complications. Since its discovery, proprotein convertase subtilisin/kexin type 9 (PCSK9) has been reported to be involved in the pathology of various CVDs, with studies showing a positive association between plasma levels of PCSK9, hyperglycemia, and dyslipidemia. PCSK9 regulates lipid homeostasis by interacting with low-density lipoprotein receptors (LDLRs) present in hepatocytes and subsequently induces LDLR degradation via receptor-mediated endocytosis, thereby reducing LDL uptake from circulation. In addition, PCSK9 also induces pro-inflammatory cytokine expression and apoptotic cell death in diabetic-CVD. Furthermore, therapies designed to inhibit PCSK9 effectively reduces diabetic dyslipidemia with clinical studies reporting reduced cardiovascular events in patients with diabetes and no significant adverse effect on glycemic controls. In this review, we discuss the role of PCSK9 in the pathogenesis of diabetes-induced CVD and the potential mechanisms by which PCSK9 inhibition reduces cardiovascular events in diabetic patients.

Immune Homeostasis Maintenance Through Advanced Immune Therapeutics to Target Atherosclerosis

Atherosclerosis remains the leading cause of coronary heart disease (CHD) with enormous health and societal tolls. Traditional drug development approaches have been focused on small molecule-based compounds that aim to lower plasma lipids and reduce systemic inflammation, two primary causes of atherosclerosis. However, despite the widely available lipid-lowering and anti-inflammatory small compounds and biologic agents, CHD prevalence still remains high. Based on recent advances revealing disrupted immune homeostasis during atherosclerosis pathogenesis, novel strategies aimed at rejuvenating immune homeostasis with engineered immune leukocytes are being developed. This chapter aims to assess basic and translational efforts on these emerging strategies for the effective development of atherosclerosis treatment, as well as key challenges in this important translational field.

Genetically instrumented LDL-cholesterol lowering and multiple disease outcomes: A Mendelian randomization phenome-wide association study in the UK Biobank

AIMS

Lipid-lowering medications are widely used to control blood cholesterol levels and manage a range of cardiovascular and lipid disorders. We aimed to explore the possible associations between LDL lowering and multiple disease outcomes or biomarkers.

METHODS

We performed a Mendelian randomization phenome-wide association study (MR-PheWAS) in 337 475 UK Biobank participants to test for associations between four proposed LDL-C-lowering genetic risk scores (PCSK9, HMGCR, NPC1L1 and LDLR) and 1135 disease outcomes, with follow-up MR analyses in 52 serum, urine, imaging and clinical biomarkers. We used inverse-variance weighted MR in the main analyses and complementary MR methods (weighted median, weighted mode, MR-Egger and MR-PRESSO) as sensitivity analyses. We accounted for multiple testing with false discovery rate correction (P < 2.0 × 10-4 for phecodes, P < 1.3 × 10-2 for biomarkers).

RESULTS

We found evidence for an association between genetically instrumented LDL lowering and 10 distinct disease outcomes, suggesting potential causality. All genetic instruments were associated with hyperlipidaemias and cardiovascular diseases in the expected directions. Biomarker analyses supported an effect of LDL-C lowering through PCSK9 on lung function (FEV [beta per 1 mg/dL lower LDL-C -1.49, 95% CI -2.21, -0.78]; FVC [-1.42, 95% CI -2.29, -0.54]) and through HMGCR on hippocampal volume (beta per 1 mg/dL lower LDL-C 6.09, 95% CI 1.74, 10.44).

CONCLUSIONS

We found genetic evidence to support both positive and negative effects of LDL-C lowering through all four LDL-C-lowering pathways. Future studies should further explore the effects of LDL-C lowering on lung function and changes in brain volume.

PCSK-9 Inhibitors and Cardiovascular Outcomes: A Systematic Review With Meta-Analysis

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have been approved to treat dyslipidaemia. However, there is a lack of knowledge on the most efficient PCSK9 therapies that target PCSK9 for secondary prevention in subjects at high risk for cardiovascular (CV) events. Thus, this study aimed to assess the efficacy and safety of anti-PCSK9 antibodies in randomized controlled trials (RCTs). A comprehensive review of the available literature was done to identify RCTs that compared the use of PCSK9 inhibitors coupled with placebo or ezetimibe for the secondary prevention of CV events in patients on statin-background therapy. All-cause mortality was the major efficacy endpoint, while severe adverse events were the key safety outcome. A random effects model was used, and data were presented as risk ratio (RR) or risk difference with their corresponding 95% confidence intervals (CI). The heterogeneity of the publications was determined using Cochran's Q test, and publication bias was visually examined using funnel plots. All the chosen studies' quality was assessed using the Critical Appraisal Checklists for Studies created by the Joanna Briggs Institute (JBI). Forty-one studies (76,304 patients: 49,086 on evolocumab, and 27,218 on alirocumab) were included, and their years of publication spanned from 2010 to 2023. Overall, no significant differences were observed in CV and all-cause mortality between PCSK9 inhibitors and controls. However, alirocumab use was linked to a reduced risk of all-cause death compared to control, but not evolocumab. Each of the drugs, evolocumab and alirocumab, significantly reduced the risk of myocardial infarction (MI), coronary revascularization, and ischemic stroke. In comparison to the control therapy, the risk of major detrimental sequelae was significantly reduced by alirocumab therapy in the subgroup analysis of each PCSK9 inhibitor, whereas evolocumab treatment did not demonstrate significant differences (RR = 0.88; 95% CI = 0.72-1.04; evolocumab: RR = 0.99; 95% CI = 0.87-1.11). Both evolocumab and alirocumab are well-tolerated, safe medications that significantly lower low-density lipoprotein (LDL) levels.

Significance of traditional herbal medicine for dyslipidemia

Dyslipidemia is a multifactorial disorder that is a causative factor and risk factor for cardiovascular disease. The incidence of dyslipidemia is expected to increase because of the presence of comorbidities. Although several lipid-lowering drugs have been developed and approved, they are not completely effective and are associated with side effects. Traditional herbal medicine (THM) represents an alternative and complementary approach for managing dyslipidemia because of its low toxicity and beneficial effects, such as anti-inflammatory and antioxidant effects. This review focuses on our current understanding of the antidyslipidemic effect of THMs and discusses the associated regulatory mechanisms. The current findings indicate that THM may lead to the development of novel therapeutic regimens for dyslipidemia.

The STROMICS genome study: deep whole-genome sequencing and analysis of 10K Chinese patients with ischemic stroke reveal complex genetic and phenotypic interplay

Ischemic stroke is a leading cause of global mortality and long-term disability. However, there is a paucity of whole-genome sequencing studies on ischemic stroke, resulting in limited knowledge of the interplay between genomic and phenotypic variations among affected patients. Here, we outline the STROMICS design and present the first whole-genome analysis on ischemic stroke by deeply sequencing and analyzing 10,241 stroke patients from China. We identified 135.59 million variants, > 42% of which were novel. Notable disparities in allele frequency were observed between Chinese and other populations for 89 variants associated with stroke risk and 10 variants linked to response to stroke medications. We investigated the population structure of the participants, generating a map of genetic selection consisting of 31 adaptive signals. The adaption of the MTHFR rs1801133-G allele, which links to genetically evaluated VB9 (folate acid) in southern Chinese patients, suggests a gene-specific folate supplement strategy. Through genome-wide association analysis of 18 stroke-related traits, we discovered 10 novel genetic-phenotypic associations and extensive cross-trait pleiotropy at 6 lipid-trait loci of therapeutic relevance. Additionally, we found that the set of loss-of-function and cysteine-altering variants present in the causal gene NOTCH3 for the autosomal dominant stroke disorder CADASIL displayed a broad neuro-imaging spectrum. These findings deepen our understanding of the relationship between the population and individual genetic layout and clinical phenotype among stroke patients, and provide a foundation for future efforts to utilize human genetic knowledge to investigate mechanisms underlying ischemic stroke outcomes, discover novel therapeutic targets, and advance precision medicine.

Discovery of [5,5'-bibenzo[d][1,3]dioxol]-6-substituted amine derivatives as potent proprotein convertase subtilisin/kexin type 9 inhibitors

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has emerged as a promising therapeutic target for the treatment of hyperlipidemia. In discovery of novel small molecules that interfere PCSK9/LDLR protein-protein interaction (PPI), structural modification was performed based on our previously derived compounds. A series of [5,5'-bibenzo[d][1,3]dioxol]-6-amine analogs were designed and synthesized for the activity evaluation. In the PCSK9/LDLR PPI impairing test, molecules D28 and D29, exhibited remarkable inhibitory potency with IC50 values of 8.30 and 6.70 μM compared with SBC-115337 (17.89 μM), respectively. Molecular docking predicted the binding pattern of compounds D28 and D29 in the LDLR binding site of PCSK9. Hydrophobic interactions play an important role in the binding of aromatic molecular fragments to the pockets in the PCSK9/LDLR binding interface. Further LDLR expression and LDL uptake studies revealed that both D28 and D29 restored LDLR expression on the surface of hepatic HepG2 cells and improved extracellular LDL uptake in the presence of PCSK9. It is significant that molecules D28 and D29 exhibited potential for the treatment of hyperlipidemia in current in vitro investigations. Generally, lead compounds with novel structures were developed in the present study for further design of lipid-lowering molecules by targeting PCSK9/LDLR PPI.

PCSK9 inhibition interrupts the cross-talk between keratinocytes and macrophages and prevents UVB-induced skin damage

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is an enzyme that promotes the degradation of low-density lipoprotein receptors. It is involved in hyperlipidemia as well as other diseases, such as cancer and skin inflammation. However, the detailed mechanism for PCSK9 on ultraviolet B (UVB)-induced skin lesions was not clear. Thus, the role and possible action mechanism of PCSK9 in UVB-induced skin damage in mice were studied here using siRNA and a small molecule inhibitor (SBC110736) against PCSK9. Immunohistochemical staining revealed a significant increase in PCSK9 expression after UVB exposure, indicating the possible role of PCSK9 in UVB damage. Skin damage, increase in epidermal thickness, and keratinocyte hyperproliferation were significantly alleviated after treatment with SBC110736 or siRNA duplexes, compared with that in the UVB model group. Notably, UVB exposure triggered DNA damage in keratinocytes, whereas substantial interferon regulatory factor 3 (IRF3) activation was observed in macrophages. Pharmacologic inhibition of STING or cGAS knockout significantly reduced UVB-induced damage. In the co-culture system, supernatant from UVB-treated keratinocyte induced IRF3 activation in macrophages. This activation was inhibited with SBC110736 and by PCSK9 knockdown. Collectively, our findings reveal that PCSK9 plays a critical role in the crosstalk between damaged keratinocytes and STING activation in macrophages. The interruption of this crosstalk by PCSK9 inhibition may be a potential therapeutic strategy for UVB-induced skin damage.

The Importance of Being Aware of Intrinsic Methods' Limitation in Low-Density Lipoprotein Cholesterol Determination to Correctly Identify Cardiovascular Risk: Is Direct Determination Obtained with the Roche System Systematically Overestimating LDL in Very High-Risk Patients with Triglycerides Concentration of Less than 2.25 mmol/L?

BACKGROUND

low-density lipoprotein cholesterol (LDL-C) is a strong cardiovascular risk factor, but the methods used to correctly determine it are is still questioned. The aim of this study was to compare the direct determination of LDL-C levels, obtained with the Roche cobas c system, with LDL-C values calculated through Sampson's and Friedewald's equations in very high-risk patients with triglycerides concentrations of less than 2.25 mmol/L (<200 mg/dL).

METHODS

in 127 consecutive patients with a recent diagnosis of acute coronary syndrome and triglycerides of less than 2.25 mmol/L, plasma LDL-C was measured directly and calculated with Sampson's and Friedewald's equations before hospital discharge, and the data were compared.

RESULTS

median LDL values obtained with the Friedenwald and Sampson equations and with direct determination were 2.31 (IQR 1.59-3.21), 2.36 (IQR 1.66-3.26) and 2.64 (IQR 1.97-3.65) mmol/L, respectively. Direct measurements were higher by 0.35 and 0.40 mmol/L when compared to the levels calculated with Sampson's or Friedewald's equations, respectively (p < 0.01). The correlation between the two equations was almost perfect (rho 0.997) but decreased when the directly determined data were compared to those calculated with Sampson's equation (rho 0.954) or Friedewald's method (rho 0.939).

CONCLUSION

direct determination generated higher values of LDL-C concentration through a probable systematic overestimation.

Calculated LDL-cholesterol: comparability of the extended Martin/Hopkins, Sampson/NIH, Friedewald and four other equations in South African patients

AIMS

The reference method for low-density lipoprotein-cholesterol (LDL-C) is ultracentrifugation. However, this is unsuitable for routine use and therefore direct LDL-C assays and predictive equations are used. In this study, we compared the Friedewald, extended Martin/Hopkins, Sampson/NIH and four other equations to a direct assay.

METHODS

We analysed 44 194 lipid profiles from a mixed South African population. The LDL-C predictive equations were compared with direct LDL-C assay and analysed using non-parametric statistics and error grid analysis.

RESULTS

Both the extended Martin/Hopkins and Sampson/NIH equations displayed the best correlation with direct LDL-C in terms of desirable bias and total allowable error. The direct LDL-C assay classified 13.9% of patients in the low LDL-C (1.0-1.8 mmol/L) category, in comparison to the extended Martin/Hopkins equation (13.4%), the Sampson equation (14.6%) and the Friedewald equation (16.0%). The Sampson/NIH was least biased in the low LDL-C category (<1.8 mmol/L) and produced the least overall clinically relevant errors compared with the extended Martin/Hopkins and Friedewald equations in the low-LDL-C category.

CONCLUSIONS

Our findings suggest only a marginal difference between the extended Martin/Hopkins equation and the Sampson/NIH equation with the use of the Beckman Coulter DxC800 analyser in this population. The results favour the implementation of the Sampson/NIH equation when the Beckman Coulter DxC analyser is used, but the extended Martin/Hopkins may also be safely implemented. Both of these equations performed significantly better than the Friedewald equation. We recommend that patients be monitored using one of these methods and that each laboratory perform its own validation of either equation to ensure continuation and accuracy, and to prevent between-method variation.

Pharmacotherapeutics for dyslipidemia management

ABSTRACT

Effective management of dyslipidemia is of paramount importance to prevent cardiovascular (CV) complications. Using current clinical practice guidelines is recommended to correct lipid levels and prevent further pathologic processes. This article presents an overview of treatment options for patients with dyslipidemia and CV disease, with a special focus on the following drug classes: HMG-CoA reductase inhibitors (also called statins), cholesterol absorption inhibitors (ezetimibe), bile acid sequestrants, fibrates, icosapent ethyl, and PCSK9 inhibitors.

Improved cytosine base editors generated from TadA variants

Cytosine base editors (CBEs) enable programmable genomic C·G-to-T·A transition mutations and typically comprise a modified CRISPR-Cas enzyme, a naturally occurring cytidine deaminase, and an inhibitor of uracil repair. Previous studies have shown that CBEs utilizing naturally occurring cytidine deaminases may cause unguided, genome-wide cytosine deamination. While improved CBEs that decrease stochastic genome-wide off-targets have subsequently been reported, these editors can suffer from suboptimal on-target performance. Here, we report the generation and characterization of CBEs that use engineered variants of TadA (CBE-T) that enable high on-target C·G to T·A across a sequence-diverse set of genomic loci, demonstrate robust activity in primary cells and cause no detectable elevation in genome-wide mutation. Additionally, we report cytosine and adenine base editors (CABEs) catalyzing both A-to-I and C-to-U editing (CABE-Ts). Together with ABEs, CBE-Ts and CABE-Ts enable the programmable installation of all transition mutations using laboratory-evolved TadA variants with improved properties relative to previously reported CBEs.

Real-World Outcomes of Proprotein Convertase Subtilisin Kexin-9 Inhibitor Use

ABSTRACT

Although the proprotein convertase subtilisin kexin-9 inhibitors (PCSK9i) were shown to significantly lower low-density lipoprotein and reduce atherosclerotic cardiovascular disease events in clinical trials, there is a dearth of use data on these agents in real-world settings. This study compares PCSK9i use in a population of real-world patients with atherosclerotic cardiovascular disease or familial hypercholesterolemia. This was a matched cohort study of adult patients who were dispensed a PCSK9i along with adult patients who did not receive a PCSK9i. PCSK9i patients were matched on a propensity to have received a PCSK9i score up to 1:10 to non-PCSK9i patients. The primary outcomes were changes in cholesterol levels. Secondary outcomes included a composite outcome of all-cause mortality, major cardiovascular events, and ischemic strokes along with health care utilization during follow-up. Adjusted conditional, multivariate Cox proportional hazards, and negative binomial modeling were performed. Ninety-one PCSK9i patients were matched to 840 non-PCSK9i patients. Seventy-one percent of PCSK9i patients either discontinued or switched PCSK9i therapy. PCSK9i patients had greater median reductions in low-density lipoprotein (-73.0 mg/dL vs. -30.0 mg/dL) and total (-77.0 vs. -31.0) cholesterol (both P < 0.001). No adjusted between-group differences in the composite outcome or individual components of the composite outcome were identified (all P > 0.05). PCSK9i patients had a lower rate of medical office visits during follow-up (adjusted incidence rate ratio = 0.61, P = 0.019). These findings support the effectiveness of PCSK9i therapy in real-world settings but suggest that use may be limited by PCSK9i adverse reactions and patient cost barriers.

The clinical effects of inclisiran, a first-in-class LDL-C lowering siRNA therapy, on the LDL-C levels in Chinese patients with hypercholesterolemia

BACKGROUND

Inclisiran is a novel siRNA therapy that inhibits the synthesis of proprotein convertase subtilisin-kexin type 9 (PCSK9) by targeting the PCSK9 mRNA, consequently, decreases low-density lipoprotein cholesterol (LDL-C).

OBJECTIVE

To assess the safety, PK and LDL-C lowering effects of inclisiran in the Chinese patients with elevated LDL-C despite treatment with maximally tolerated LDL-C lowering therapies.

METHODS

Forty Chinese patients with hypercholesterolemia (LDL-C ≥100 mg/dL) who were on maximally tolerated statin were randomized to receive a single dose of either inclisiran sodium 100 or 300mg s.c. injection (each for 15 patients) or placebo (10 patients). Safety, pharmacokinetics and pharmacodynamics (i.e., PCSK9 and LDL-C levels) were evaluated for up to 90 days after the s.c. injection of study drug.

RESULTS

Following single subcutaneous injections inclisiran sodium at 100 mg or 300 mg, inclisiran has a relative short elimination half-life (T1/2, 6.5 hours). Both plasma PCSK9 and serum LDL-C decreased rapidly and consistently, with the maximal reduction between Day 30 and Day 60; then the decreases of PCSK9 and LDL-C were generally maintained up to 56.4% and 49.6% of 100 mg, 74.9% and 58.3% of 300 mg, respectively, at day 90. All adverse events were mild or moderate in severity, and no discontinuations due to adverse events. There were no serious adverse events being reported.

CONCLUSIONS

Inclisiran was generally safe and well tolerated. Single dose of both Inclisiran 100 and 300 mg significantly reduced PCSK9 and LDL-C levels in Chinese patients up to Day 90. The greatest reductions were observed with the 300 mg regimen of Inclisiran.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04774003.

Emerging Therapies for the Treatment of Atherosclerotic Cardiovascular Disease: From Bench to Bedside

Primarily a consequence of sedentary lifestyle, atherosclerosis has already reached pandemic proportions, and with every year the burden of it is only increasing. As low-density lipoprotein cholesterol (LDL-C) represents a crucial factor in atherosclerosis formation and progression, stringent lipid-lowering therapy could conceivably be the key to preventing the unfavorable outcomes that arise as a consequence of atherosclerosis. The use of statins in lipid-lowering is often burdened by adverse events or is insufficient to prevent cardiovascular events as a monotherapy. Therefore, in the present review, the authors aimed to discuss the underlying mechanisms of dyslipidemia and associated atherosclerotic cardiovascular disease (ASCVD) and preclinical and clinical trials of novel therapeutic approaches to its treatment, some of which are still in the early stages of development. Apart from novel therapies, a novel change in perspective is needed. Specifically, the critical objective in the future management of ASCVD is to embrace emerging evidence in the field of atherosclerosis, because clinicians are often burden by common practice and personal experience, both of which have so far been shown to be futile in the setting of atherosclerosis.

Hepatic Alarmins and Mitochondrial Dysfunction under Residual Hyperlipidemic Stress Lead to Irreversible NAFLD

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) includes a range of progressive disorders generated by excess lipid accumulation in the liver leading to hepatic steatosis and eventually fibrosis. We aimed to identify by high performance mass spectrometry-based proteomics the main signaling pathways and liver proteome changes induced by hypercholesterolemia in a rabbit atherosclerotic model that induced high accumulation of lipids in the liver.

METHODS

The effect of combined lipid-lowering drugs (statins and anti-PCSK9 monoclonal antibody) were used after the interruption of the hypercholesterolemic diet to identify also the potential mediators, such as alarmins, responsible for the irreversible NAFLD build up under the hyperlipidemic sustained stress.

RESULTS

Proteomic analysis revealed a number of proteins whose abundance was altered. They were components of metabolic pathways including fatty-acid degradation, glycolysis/gluconeogenesis, and nonalcoholic fatty liver disease. Mitochondrial dysfunction indicated alteration at the mitochondrial respiratory chain level and down-regulation of NADH: ubiquinone oxidoreductase. The expression of a majority of cytochromes (P4502E1, b5, and c) were up-regulated by lipid-lowering treatment. Long-term hyperlipidemic stress, even with a low-fat diet and lipid-lowering treatment, was accompanied by alarmin release (annexins, galectins, HSPs, HMGB1, S100 proteins, calreticulin, and fibronectin) that generated local inflammation and induced liver steatosis and aggressive fibrosis (by high abundance of galectin 3, fibronectin, and calreticulin).

CONCLUSIONS

The novel findings of this study were related to the residual effects of hyperlipidemic stress with consistent, combined lipid-lowering treatment with statin and inhibitor of PCSK9.

Atherogenesis in Apoe-/- and Ldlr-/- Mice with a Genetically Resistant Background

Apoe-deficient (Apoe^-/-) and Ldlr-deficient (Ldlr^-/-) mice are two common animal models of hypercholesterolemia and atherosclerosis. The two models differ in lipid and glucose metabolism and other mechanisms involved in atherogenesis. Here we examined atherosclerotic lesion formation in the two models with an atherosclerosis-resistant C3H/HeJ (C3H) background. 3-month-old C3H-Ldlr^-/- and C3H-Apoe^-/- mice developed minimal atherosclerotic lesions in the aortic root when fed a chow diet. After 12 weeks on a Western diet, C3H-Ldlr^-/- mice developed 3-fold larger lesions than C3H-Apoe^-/- mice in the aortic root (127,386 ± 13,439 vs. 41,542 ± 5075 μm²/section; p = 0.00028), but neither knockout formed any lesion in the carotid artery. After being ligated near its bifurcation, the common carotid artery developed intimal lesions in both knockouts 4 weeks after ligation, significantly larger in C3H-Ldlr^-/- than C3H-Apoe^-/- mice (68,721 ± 2706 vs. 47,472 ± 8146 μm²/section; p = 0.028). Compared to C3H-Apoe^-/- mice, C3H-Ldlr^-/- mice showed a 50% reduction in plasma MCP-1 levels, similar levels of malondialdehyde, an oxidative stress biomarker, on both chow and Western diets, but higher small dense LDL levels on the Western diet. These results suggest a more significant role for small dense LDL than inflammation and oxidative stress in the different susceptibility of the mouse models to atherosclerosis.

Endocrine Regulation of Microvascular Receptor-Mediated Transcytosis and Its Therapeutic Opportunities: Insights by PCSK9-Mediated Regulation

Currently, many neurological disorders lack effective treatment options due to biological barriers that effectively separate the central nervous system (CNS) from the periphery. CNS homeostasis is maintained by a highly selective exchange of molecules, with tightly controlled ligand-specific transport systems at the blood-brain barrier (BBB) playing a key role. Exploiting or modifying these endogenous transport systems could provide a valuable tool for targeting insufficient drug delivery into the CNS or pathological changes in the microvasculature. However, little is known about how BBB transcytosis is continuously regulated to respond to temporal or chronic changes in the environment. The aim of this mini-review is to draw attention to the sensitivity of the BBB to circulating molecules derived from peripheral tissues, which may indicate a fundamental endocrine-operating regulatory system of receptor-mediated transcytosis at the BBB. We present our thoughts in the context of the recent observation that low-density lipoprotein receptor-related protein 1 (LRP1)-mediated clearance of brain amyloid-β (Aβ) across the BBB is negatively regulated by peripheral proprotein convertase subtilisin/kexin type 9 (PCSK9). We hope that our conclusions will inspire future investigations of the BBB as dynamic communication interface between the CNS and periphery, whose peripheral regulatory mechanisms could be easily exploited for therapeutic purposes.

Medical Management of Dyslipidemia for Secondary Stroke Prevention: Narrative Review

Dyslipidemia is a major risk factor for stroke, following hypertension, diabetes, and smoking, and is an important risk factor for the prevention and treatment of coronary artery disease and peripheral vascular disease, including stroke. Recent guidelines recommend considering low-density lipoprotein cholesterol (LDL-C)-lowering therapies, such as statins (preferably), ezetimibe, or proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors to prevent the occurrence or recurrence of stroke, adhering to the "lower is better" approach. In this review, we examined the evidence supporting lipid-lowering medications like statins, ezetimibe, and PCSK9 inhibitors for secondary stroke prevention and dyslipidemia management in different stroke subtypes. Stroke guidelines advocate for administering the maximum tolerable dose of statins as the primary treatment and as soon as possible despite the potential for new-onset diabetes mellitus and possible muscle and liver toxicity due to their demonstrated benefits in secondary prevention of cardiovascular diseases and mortality reduction. When statin use is insufficient for LDL lowering, ezetimibe and PCSK9 inhibitors are recommended as complementary therapies. It is essential to establish lipid-lowering therapy goals based on the stroke subtype and the presence of comorbidities.

Inclisiran—A Revolutionary Addition to a Cholesterol-Lowering Therapy

Hypercholesterolemia plays a crucial role in the development of atherosclerosis, but it remains an undertreated and underdiagnosed disease. Taking into consideration the high prevalence of lipid disorders, long duration of the asymptomatic course of the disease, life-threatening complications resulting from inaccurate therapy, and stringent treatment goals concerning LDL cholesterol level in the prevention of cardiovascular events, novel lipid-lowering therapies have been introduced in the last few years. In this article, a drug belonging to the group of small interfering RNA (siRNA) called inclisiran is described. It is a novel molecule that increases the number of LDL receptors (LDLRs) on the surface of hepatic cells by preventing the formation of proprotein convertase subtilisin/kexin type 9 (PCSK9) responsible for the degradation of LDLRs. With great potential for lowering plasma LDL cholesterol level, high liver specificity, comfortable dosing regimen, and good tolerance without significant adverse effects, it could play an important part in future hypolipemic therapies.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) in the central nervous system

The gene encoding proprotein convertase subtilisin/kexin type 9 (PCSK9) and its protein product have been widely studied for their role in cholesterol and lipid metabolism. PCSK9 increases the rate of metabolic degradation of low-density lipoprotein receptors, preventing the diffusion of low-density lipoprotein (LDL) from plasma into cells and contributes to high lipoprotein-bound cholesterol levels in the plasma. While most research has focused on the regulation and disease relevance of PCSK9 to the cardiovascular system and lipid metabolism, there is a growing body of evidence that PCSK9 plays a crucial role in pathogenic processes in other organ systems, including the central nervous system. PCSK9's impact on the brain is not yet fully understood, though several recent studies have sought to illuminate its impact on various neurodegenerative and psychiatric disorders, as well as its connection with ischemic stroke. Cerebral PCSK9 expression is low but is highly upregulated during disease states. Among others, PCSK9 is known to play a role in neurogenesis, neural cell differentiation, central LDL receptor metabolism, neural cell apoptosis, neuroinflammation, Alzheimer's Disease, Alcohol Use Disorder, and stroke. The PCSK9 gene contains several polymorphisms, including both gain-of-function and loss-of-function mutations which profoundly impact normal PCSK9 signaling and cholesterol metabolism. Gain-of-function mutations lead to persistent hypercholesterolemia and poor health outcomes, while loss-of-function mutations generally lead to hypocholesterolemia and may serve as a protective factor against diseases of the liver, cardiovascular system, and central nervous system. Recent genomic studies have sought to identify the end-organ effects of such mutations and continue to identify evidence of a much broader role for PCSK9 in extrahepatic organ systems. Despite this, there remain large gaps in our understanding of PCSK9, its regulation, and its effects on disease risk outside the liver. This review, which incorporates data from a wide range of scientific disciplines and experimental paradigms, is intended to describe PCSK9's role in the central nervous system as it relates to cerebral disease and neuropsychiatric disorders, and to examine the clinical potential of PCSK9 inhibitors and genetic variation in the PCSK9 gene on disease outcomes, including neurological and neuropsychiatric disease.

A Systematic Review of the Randomized Controlled Trials of Gemcabene and Its Therapeutic Uses

Statins are the most widely used drugs for reducing lipid and cholesterol levels in the blood. However, statins have shown some adverse effects and less acceptance among patients; hence, new drugs have been promoted in the market. Furthermore, gemcabenes were discovered in 1995 and are now in phase II and III clinical trials. Gemcabene acts by inhibiting incorporation of 14C-acetate into hepatocytes and stops the mechanism of fatty acids and cholesterol synthesis. In this review the six randomized controlled trials (RCTs) were scrutinized from the two databases by using keywords "Gemcabene" AND "Randomized Controlled Trial." The trials were mainly on animal models, and two studies were found to be associated with human subjects. The study concluded that gemcabene was effective as an anti-inflammatory agent and reduced lipid levels and the progression of fibrosis. Hence, further controlled trials are needed to determine its efficacy and safety in human subjects, along with the identification of adverse effects.

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.

Cholesterol-Related lncRNAs as Response Predictors of Atorvastatin Treatment in Chilean Hypercholesterolemic Patients: A Pilot Study

Statins are currently the treatment of choice for hypercholesterolemia. However, wide interindividual variability has been observed in the response to treatment. Recent studies have reported the role of lncRNAs in the metabolism of lipids; nevertheless, there are few studies to date that show their role in the response to treatment with statins. Thus, the aim of this study was to assess the levels of expression of three lncRNAs (RP1-13D10.2; MANTIS; lncHR1) associated with genes involved in cholesterol homeostasis in leukocyte cells of hypercholesterolemic patients after treatment with atorvastatin and compare them with levels in subjects with normal cholesterol levels. A secondary aim was to assess the levels of expression in monocytic THP-1 cells differentiated to macrophages. The study included 20 subjects with normal cholesterol (NC) levels and 20 individuals with hypercholesterolemia (HC). The HC patients were treated with atorvastatin (20 mg/day/4 weeks). THP-1 cells were differentiated to macrophages with PMA and treated with different doses of atorvastatin for 24 h. Expression of lncRNAs was determined by RT-qPCR. The lncRNAs RP1-13D10.2 (p < 0.0001), MANTIS (p = 0.0013) and lncHR1 (p < 0.0001) presented increased expression in HC subjects compared with NC subjects. Furthermore, atorvastatin had a negative regulatory effect on the expression of lncHR1 (p < 0.0001) in HC subjects after treatment. In vitro, all the lncRNAs showed significant differences in expression after atorvastatin treatment. Our findings show that the lncRNAs tested present differential expression in HC patients and play a role in the variability reported in the response to atorvastatin treatment. Further research is needed to clarify the biological impact of these lncRNAs on cholesterol homeostasis and treatment with statins.

Development of Novel siRNA Therapeutics: A Review with a Focus on Inclisiran for the Treatment of Hypercholesterolemia

Over the past two decades, it was discovered that introducing synthetic small interfering RNAs (siRNAs) into the cytoplasm facilitates effective gene-targeted silencing. This compromises gene expression and regulation by repressing transcription or stimulating sequence-specific RNA degradation. Substantial investments in developing RNA therapeutics for disease prevention and treatment have been made. We discuss the application to proprotein convertase subtilisin/kexin type 9 (PCSK9), which binds to and degrades the low-density lipoprotein cholesterol (LDL-C) receptor, interrupting the process of LDL-C uptake into hepatocytes. PCSK9 loss-of-function modifications show significant clinical importance by causing dominant hypocholesterolemia and lessening the risk of cardiovascular disease (CVD). Monoclonal antibodies and small interfering RNA (siRNA) drugs targeting PCSK9 are a significant new option for managing lipid disorders and improving CVD outcomes. In general, monoclonal antibodies are restricted to binding with cell surface receptors or circulating proteins. Similarly, overcoming the intracellular and extracellular defenses that prevent exogenous RNA from entering cells must be achieved for the clinical application of siRNAs. N-acetylgalactosamine (GalNAc) conjugates are a simple solution to the siRNA delivery problem that is especially suitable for treating a broad spectrum of diseases involving liver-expressed genes. Inclisiran is a GalNAc-conjugated siRNA molecule that inhibits the translation of PCSK9. The administration is only required every 3 to 6 months, which is a significant improvement over monoclonal antibodies for PCSK9. This review provides an overview of siRNA therapeutics with a focus on detailed profiles of inclisiran, mainly its delivery strategies. We discuss the mechanisms of action, its status in clinical trials, and its prospects.

Current Insights on Dyslipidaemia Management for Prevention of Atherosclerotic Cardiovascular Disease: A Malaysian Perspective

Dyslipidaemia is highly prevalent in the Malaysian population and is one of the main risk factors for atherosclerotic cardiovascular disease (ASCVD). Low-density lipoprotein cholesterol (LDL-C) is recognised as the primary target of lipid-lowering therapy to reduce the disease burden of ASCVD. Framingham General CV Risk Score has been validated in the Malaysian population for CV risk assessment. The Clinical Practice Guidelines (CPG) on the management of dyslipidaemia were last updated in 2017. Since its publication, several newer randomised clinical trials have been conducted with their results published in research articles and compared in meta-analysis. This underscores a need to update the previous guidelines to ensure good quality care and treatment for the patients. This review summarises the benefits of achieving LDL-C levels lower than the currently recommended target of < 1.8mmol/L without any safety concerns. In most high and very high-risk individuals, statins are the first line of therapy for dyslipidaemia management. However, certain high-risk individuals are not able to achieve the LDL-C goal as recommended in the guideline even with high-intensity statin therapy. In such individuals, lower LDL-C levels can be achieved by combining the statins with non-statin agents such as ezetimibe and PCSK9 inhibitors. Emerging non-statin lipid-lowering therapies and challenges in dyslipidaemia management are discussed in this article. The review also summarises the recent updates on local and international guidelines for dyslipidaemia management.

Low density lipoprotein receptor endocytosis in cardiovascular disease and the factors affecting LDL levels

Cardiovascular disease (CVD) is the one of major global health issues with approximately 30% of the mortality reported in the mid-income population. Low-density lipoprotein (LDL) plays a crucial role in development of CVD. High LDL along with others forms a plaque and blocks arteries, resulting in CVD. The present chapter deals with the mechanism of receptor-mediated endocytosis of LDL and its management by drugs such as statins and PCSK9 inhibitors along with dietary supplementation for health improvements.

Investigating the potential impact of PCSK9-inhibitors on mood disorders using eQTL-based Mendelian randomization

Prescription of PCSK9-inhibitors has increased in recent years but not much is known about its off-target effects. PCSK9-expression is evident in non-hepatic tissues, notably the brain, and genetic variation in the PCSK9 locus has recently been shown to be associated with mood disorder-related traits. We investigated whether PCSK9 inhibition, proxied by a genetic reduction in expression of PCSK9 mRNA, might have a causal adverse effect on mood disorder-related traits. We used genetic variants in the PCSK9 locus associated with reduced PCSK9 expression (eQTLs) in the European population from GTEx v8 and examined the effect on PCSK9 protein levels and three mood disorder-related traits (major depressive disorder, mood instability, and neuroticism), using summary statistics from the largest European ancestry genome-wide association studies. We conducted summary-based Mendelian randomization analyses to estimate the causal effects, and attempted replication using data from eQTLGen, Brain-eMETA, and the CAGE consortium. We found that genetically reduced PCSK9 gene-expression levels were significantly associated with reduced PCSK9 protein levels but not with increased risk of mood disorder-related traits. Further investigation of nearby genes demonstrated that reduced USP24 gene-expression levels was significantly associated with increased risk of mood instability (p-value range = 5.2x10-5-0.03), and neuroticism score (p-value range = 2.9x10-5-0.02), but not with PCSK9 protein levels. Our results suggest that genetic variation in this region acts on mood disorders through a PCSK9-independent pathway, and therefore PCSK9-inhibitors are unlikely to have an adverse impact on mood disorder-related traits.

Diaporisoindole B Reduces Lipid Accumulation in THP-1 Macrophage Cells via MAPKs and PPARγ-LXRα Pathways and Promotes the Reverse Cholesterol Transport by Upregulating SR-B1 and LDLR in HepG2 Cells

Diaporisoindole B (DPB), an isoprenylisoindole alkaloid isolated from the mangrove endophytic fungus Diaporthe sp. SYSU-HQ3, has been proved to have a good anti-inflammatory activity in macrophage cells. In this study, we found that DPB was able to reduce lipid accumulation in THP-1 macrophage-derived foam cells. DPB could inhibit the lipid influx-related gene CD36 and increase the expression of lipid efflux-related genes ATP binding cassette transporter A1 (ABCA1), ATP binding cassette transporter G1 (ABCG1), and scavenger receptor B1 (SR-B1). Moreover, DPB elevated low-density lipoprotein receptor (LDLR) protein expression in HepG2 cells, which can increase the transport of LDL. Meanwhile, DPB could downregulate the expression levels of proteins related to cholesterol and fatty acid synthesis. Further study showed that DPB could activate peroxisome proliferator-activated receptor gamma (PPARγ) and inhibit mitogen-activated protein kinase (MAPK) phosphorylation. Taken together, our findings demonstrated that DPB could reduce lipid accumulation in THP-1 macrophage cells by reducing the intake of lipids and promoting the efflux of lipids and also could promote the reverse cholesterol transport (RCT) mechanism by upregulating SR-B1 and LDLR in HepG2 cells.

Recent Update on the Development of PCSK9 Inhibitors for Hypercholesterolemia Treatment

The proprotein convertase subtilisin/kexin-type 9 (PCSK9) binds to low-density lipoprotein receptors (LDLR), thereby trafficking them to lysosomes upon endocytosis and enhancing intracellular degradation to prevent their recycling. As a result, the levels of circulating LDL cholesterol (LDL-C) increase, which is a prominent risk factor for developing atherosclerotic cardiovascular diseases (ASCVD). Thus, PCSK9 has become a promising therapeutic target that offers a fertile testing ground for new drug modalities to regulate plasma LDL-C levels to prevent ASCVD. In this review, we have discussed the role of PCSK9 in lipid metabolism and briefly summarized the current clinical status of modalities targeting PCSK9. In particular, a detailed overview of peptide-based PCSK9 inhibitors is presented, which emphasizes their structural features and design, therapeutic effects on patients, and preclinical cardiovascular disease (CVD) models, along with PCSK9 modulation mechanisms. As a promising alternative to monoclonal antibodies (mAbs) for managing LDL-C, anti-PCSK9 peptides are emerging as a prospective next generation therapy.

Accuracy and Clinical Impact of Estimating Low-Density Lipoprotein-Cholesterol at High and Low Levels by Different Equations

New more effective lipid-lowering therapies have made it important to accurately determine Low-density lipoprotein-cholesterol (LDL-C) at both high and low levels. LDL-C was measured by the β-quantification reference method (BQ) (N = 40,346) and compared to Friedewald (F-LDL-C), Martin (M-LDL-C), extended Martin (eM-LDL-C) and Sampson (S-LDL-C) equations by regression analysis, error-grid analysis, and concordance with the BQ method for classification into different LDL-C treatment intervals. For triglycerides (TG) < 175 mg/dL, the four LDL-C equations yielded similarly accurate results, but for TG between 175 and 800 mg/dL, the S-LDL-C equation when compared to the BQ method had a lower mean absolute difference (mg/dL) (MAD = 10.66) than F-LDL-C (MAD = 13.09), M-LDL-C (MAD = 13.16) or eM-LDL-C (MAD = 12.70) equations. By error-grid analysis, the S-LDL-C equation for TG > 400 mg/dL not only had the least analytical errors but also the lowest frequency of clinically relevant errors at the low (<70 mg/dL) and high (>190 mg/dL) LDL-C cut-points (S-LDL-C: 13.5%, F-LDL-C: 23.0%, M-LDL-C: 20.5%) and eM-LDL-C: 20.0%) equations. The S-LDL-C equation also had the best overall concordance to the BQ reference method for classifying patients into different LDL-C treatment intervals. The S-LDL-C equation is both more analytically accurate than alternative equations and results in less clinically relevant errors at high and low LDL-C levels.

Bempedoic acid and its role in contemporary management of hyperlipidemia in atherosclerosis

Atherosclerotic heart disease is the leading cause of mortality and morbidity in the USA. Low density lipoprotein (LDL) has been the target for many hypolipidemic agents to modify atherosclerotic risk. Bempedoic acid is a novel hypolipidemic drug that inhibits the enzymatic activity of ATP citrate lyase in the cholesterol synthesis pathway. CLEAR Harmony, CLEAR Wisdom, CLEAR Tranquillity and CLEAR Serenity have shown safety and efficacy associated with long term administration of this drug. Studies have shown effectiveness in reducing LDL-C in both statin intolerant patients and in patients on maximally tolerated doses of statin. The fixed drug combination of bempedoic acid and ezetimibe in a recent phase III showed significant reduction in LDL compared with placebo, which might be a promising future for LDL reduction among statin intolerant patients. Bempedoic acid also reduced inflammatory markers like hs-CRP. Given these results, bempedoic acid alone and in combination with ezetimibe received the USA FDA approval for adults with heterozygous familial hypercholesterolaemia or established atherosclerotic cardiovascular disease. We present a comprehensive review exploring the underlying mechanism, pre-clinical studies, and clinical trials of bempedoic acid and discuss the potential future role of the drug in treating hyperlipidaemia.

Amino Acid Conjugates of 2-Mercaptobenzimidazole Ameliorates High-Fat Diet-Induced Hyperlipidemia in Rats via Attenuation of HMGCR, APOB, and PCSK9

PURPOSE

This study was designed to explore the antihyperlipidemic effects of amino acid derivatives of 2-mercaptobenzimidazole (4J and 4K) in high-fat diet (HFD)-fed rats.

METHODS

Male Sprague-Dawley rats were divided into nine groups which received either standard diet or HFD for 28 days. Blood samples were taken on 27th day from HFD-fed rats to ensure hyperlipidemia. HFD-induced hyperlipidemic rats later received daily dosing of either vehicle or simvastatin (SIM; 20 mg/kg) or 4J/4K compounds (10, 20, and 30 mg/kg) for 12 consecutive days. On 40th day, animals were sacrificed, and blood samples were collected for the determination of serum lipid profile and liver function parameters. Liver samples were harvested for histopathological, antioxidant, and qPCR analyses. Molecular docking of tested compounds with HMGCR was also performed to assess the binding affinities.

RESULTS

4J and 4K dose dependently decreased serum total cholesterol, triglycerides, low-density lipoprotein, very low-density lipoproteins, alanine transaminase (ALT), and aspartate aminotransferase (AST) levels while significantly alleviated high-density lipoproteins. However, SIM failed to reduce AST and ALT levels. Moreover, tested compounds displayed antioxidant effects by inducing superoxide dismutase and glutathione levels. Histopathology data also displayed protective effects of 4J and 4K against HFD-induced fatty changes and hepatic damage. In addition, 4J and 4K downregulated transcript levels of HMGCR, APOB, PCSK9, and VCAM1, and molecular docking analysis also supported the experimental data.

CONCLUSION

It is conceivable from this study that 4J and 4K exert their antihyperlipidemic effects by modulating multiple targets regulating lipid levels.